Journal of Dentistry - Articles in Press

Acidogenic potential of soy and bovine milk beverages - Accepted Manuscript

2012-05-21

Abstract: Soy beverages are water extracts of whole soybeans and are often promoted as a healthy alternative to bovine milk. Little analysis has been carried out to determine the effects of soy beverages on oral health, especially their potential acidogenicity.Objectives: The aim of this study was to determine the potential acidogenicity of a range of soy and bovine milk beverages.Methods: In vitro acid production by Streptococcus mutans was measured in soy and milk beverages at a constant pH of 6.5 or 5.5, as was the fall in pH over a ten min period. The acid buffering capacity and calcium and phosphate concentrations (total and soluble) of the beverages were also determined.Results: The rate of acid production by S. mutans in the milk beverages was five to six times lower at pH 6.5 than in the soy beverages and three to five times lower at pH 5.5. Whilst the pH fall in the presence of S. mutans over ten min was negligible in the milk beverages there was a significant decrease in pH in the soy beverages. This was also reflected in the lower buffering capacity of the soy beverages. The levels of soluble calcium in the soy beverages were lower than those in the milk beverages although total calcium contents were similar.Conclusions: Soy beverages have a higher potential acidogenicity than bovine milk beverages.

Morphology and bacterial colonization of tooth/ceramic restoration interface after different cement excess removal techniques - Accepted Manuscript

2012-05-21

Abstract: Objectives: To evaluate the influence of different protocols for resin cement removal during cementation on biofilm formation.Methods: Twenty-eight ceramic blocks, which were injected under pressure, were placed over enamel blocks obtained from freshly extracted bovine incisors. The ceramic blocks were cemented to the enamel blocks using a dual-cured resin cement and the excess resin was removed according to the experimental group: TS: Teflon spatula; BR: brush; BR+: brush and polishing; SB+: scalpel blade and polishing. After autoclaving, the samples were colonized by incubation in a sucrose broth suspension standardized with Streptococcus mutans in microaerophilic stove. Specimens were quantitatively analyzed for bacterial adherence at the adhesive interface using confocal laser scanning microscopy and counting the colony forming units, and qualitatively analyzed using SEM. The roughness (Ra/Rz/RSm) was also analyzed. Data were analyzed by 1-way ANOVA and Tukey's test (5%).Results: The roughness values ranged from 0.96 to 1.69μm for Ra (p>0.05), from 11.59 to 22.80μm for Rz (p=0.02<0.05) and from 293.2 to 534.3μm for RSm (p=0.00). Bacterial adhesion varied between 1974000 and 2814000 CFU/ml (p=0.00). Biofilm mean thickness ranged from 0.477 and 0.556μm (p>0.05), while the biovolume values were between 0.388 and 0.547μm3/μm2 (p=0.04). Lower values for roughness, bacterial adhesion, biofilm thickness and biovolume were found with BR, while TS presented the highest values for most of the parameters. SEM images confirmed the quantitative values.Conclusions: The restoration margin morphology and interface roughness affects bacterial accumulation. The brush technique promoted less bacterial colonization at the adhesive interface than did the other removal methods.

Surface characterization of dental Y-TZP ceramic after air abrasion treatment - Uncorrected Proof

Lubica Hallmann, Peter Ulmer, Eric Reusser, Christoph H.F. Hämmerle — 2012-05-17

Abstract: Objective: The aim of this study was to characterize the surface of Y-TZP after abrasion with various airborne particles.Methods: The Y-TZP blanks were cut into 44 discs and sintered according to the manufacturer's instructions. The specimens were treated as follows: (a) control specimens, (b) abraded with 50μm alumina, (c) abraded with 110μm alumina, (d) abraded with 30μm silica-coated alumina, (e) abraded with 110μm silica-coated alumina, (f) abraded with 110μm alumina followed by 110μm silica-coated alumina particles. Airborne abrasion was performed at a pressure of 2.5bar for 15s/cm2. The Y-TZP was characterized using X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and X-ray diffraction analysis (XRD).Results: Surface morphology of Y-TZP ceramic was changed after the airborne abrasion process compared to the control specimens. The grain boundaries disappeared and part of the airborne particles are embedded and/or rested on the ceramic surfaces. The elemental composition of the Y-TZP surface after the airborne abrasion process depended on the type and size of these particles. The concentration of Si resulted higher after the airborne abrasion process with 110μm alumina followed by 110μm silica-coated alumina particles in comparison to the specimens abraded with 110μm silica-coated alumina particles. The ratio of elements normalized by yttrium for these specimens was: [Zr]/[Y]/[Al]/[Si]=15.2/1.0/26.0/73.6, respectively.Conclusion: The change of grain topography occurred during each impact process. Silica nano-particles covered not only loosely the abraded ceramic surface after abrasion process, but the release of kinetic energy in form of thermal energy resulted in melting of the ceramic surface and in the formation of zirconium silicate.

Development of a patient-based questionnaire about emotional and social issues related to eating with dentures - Uncorrected Proof

S.A.M. Kelly, R.M. Hyland, J.S. Ellis, J.M. Thomason, P.J. Moynihan — 2012-05-14

Abstract: Objectives: In order to fully assess the impact of prosthetic rehabilitation and to formulate appropriate dietary advice, in-depth information about patients’ experiences of eating with dentures is needed. The objective of this study was to develop and validate a questionnaire that accurately reflected the real concerns of patients with dental prostheses about the aspects of their life related to eating, using detailed information derived from qualitative interviews with patients.Methods: Themes around factors related to eating with dentures were derived from interviews with patients (n=66) with either implant-supported mandibular over-dentures or conventional dentures. The themes were used to design a self-completed questionnaire with questions scored on a visual analogue scale and additionally questions answered using free text. The content and face validity of the questionnaire was tested on a different group of patients (n=10) with implant-supported mandibular over-dentures (‘implant-supported’) or conventional dentures. Test–retest reliability analysis was conducted on a further group of 30 patients (n=15 implant-supported; n=15 conventional dentures).Results: A questionnaire has been developed with 33 questions scored on a visual analogue scale and 31 open questions designed to collect further information as free text. Themes identified were around social, emotional and practical issues about eating. The instrument has good internal reliability with a Cronbach alpha values of 0.86–0.95 and good test–retest reliability with intra-class correlation coefficients 0.87–0.92 across the domains.Conclusions: A patient-based instrument has been developed to measure emotional and social issues related to eating with dentures (ESIRE questionnaire). The questionnaire will be a useful tool in future trials of prosthetic rehabilitation.

Biofilm formation of Candida albicans on implant overdenture materials and its removal - Uncorrected Proof

2012-05-14

Abstract: Objectives: The purposes of this study were to clarify the surface characteristics of various implant overdenture materials and the capabilities of Candida albicans adherence and biofilm formation on these surfaces, and to investigate the role of salivary mucin in biofilm formation.Methods: Seven commonly used implant and restorative materials were assessed. The surface roughness averages of all materials were limited to 0.07–0.10μm. Contact angles and salivary mucin absorption were measured. After 90-min initial adhesion and 2-day biofilm formation, the amounts of C. albicans were determined by counting colony-forming units and the morphological characteristics were observed by scanning electron microscopy (SEM). The effects of saliva coating and the influences of material surface property on initial adhesion, biofilm formation and its removability were analysed by univariate two-way analysis of variance and multiple linear regression analysis.Results: Surface contact angle of materials, the index of hydrophobicity, was found to be correlated positively with initial adhesion and biofilm formation of C. albicans. A negative correlation between mucin absorption and removability of Candida biofilm indicates that mucin plays an important role in biofilm formation and its rigidity. SEM observation also revealed fewer Candida cells on saliva-coated Ti than on saliva-coated hydroxyapatite or acrylic resin.Conclusions: The materials with different hydrophobic property and compositions display diverse manners of salivary mucin absorption, initial adhesion and biofilm formation. The hydrophobic materials encourage enhanced initial adhesion, subsequently resulting in the active biofilm formation. Mucin has decisive effects on Candida immobilization and biofilm development on the materials.Clinical significance: Surface hydrophilic property and composition of materials and salivary proteins, especially mucin, affect the process of Candida biofilm formation and influence the amount and rigidity of formed biofilm. The present data may be applied as a reference for selecting materials in implant overdenture treatment from a microbiological point of view.

Impregnation with antimicrobials challenge bonding properties and water sorption behaviour of an acrylic liner - Uncorrected Proof

Nesreen Salim, Julian D. Satterthwaite, Riina Rautemaa, Nick Silikas — 2012-05-14

Abstract: Objectives: To investigate the effect of impregnation of poly(ethyl methacrylate) and tetrahydro-furfuryl methacrylate (PEM/THFM) polymeric delivery system with chlorhexidine or fluconazole on its shear bond strength (SBS) and water sorption.Methods: For SBS testing, 16 PEM/THFM discs impregnated with chlorhexidine (CHX), pure fluconazole (FLUp) or fluconazole from capsules (FLUc) and 16 drug-free control discs were prepared and bonded to heat-cured acrylic blocks. All discs were allowed to set for 24h at room temperature.After setting, half the discs (n=8) were tested immediately (Group 1). The other half was further incubated in water for 28 days at 37°C before testing (Group 2). To evaluate water uptake, five PEM/THFM discs impregnated with CHX, FLUp or FLUc and five drug-free control discs were prepared and incubated in water. Mass changes were measured up to six months.Results: The mean SBS for control, FLUp, CHX and FLUc discs were 4.01, 3.85, 3.29 and 2.26MPa, respectively for Group 1. Group 2 showed significantly lower SBS (P≤0.05). All failures were adhesive.The percentage mass change due to water sorption ranged significantly from 12% for control to 27% for FLUc (P≤0.05). A strong negative correlation between the extent of water absorption and the SBS was detected (R=0.94, P=0.05).Significance: Impregnation with antimicrobials presents a challenge to the physical and mechanical properties of a polymer. However, despite increased water uptake SBS remained acceptable for a temporary lining material and comparable to drug-free long-term lining materials. Moreover, the enhanced water uptake could contribute to improved leaching.

Degree of conversion of two-step etch-and-rinse adhesives: In situ micro-Raman analysis - Uncorrected Proof

2012-05-14

Abstract: Objectives: DC of three commercial two-step etch-and-rinse adhesives across the dentine–adhesive interface was investigated using micro-Raman spectroscopy. The hypothesis tested was that no difference in DC would exist among the adhesives tested.Methods: Adper Scotchbond 1XT (3M ESPE), Prime&Bond NT (Dentsply DeTrey), and Ambar (FGM) were applied on human dentine disks (n=9). Composite increments of 2mm were then applied on the adhesive surface. Raman spectra were collected along the dentine–adhesive interface. The relative intensities of the peaks associated with the mineral (PO43− at 960cm−1) and the adhesive (CC at 1640cm−1; phenyl CC at 1610cm−1) were used to identify the adhesive within the hybrid layer and calculate its DC.Results: Adper Scotchbond 1XT and Ambar showed similar DC (79±7% and 77±7%, respectively), while a lower DC was found for Prime&Bond NT (70±7%; p<0.05).Conclusions: The hypothesis tested was rejected because differences were found among the adhesives tested. The difference in DC among the three adhesive systems can be attributed to different monomer compositions and solvents. Further studies are needed to correlate DC with other mechanical properties of these adhesives.Clinical significance: Insufficient polymerization of an adhesive can result in a weak hybrid layer, and the presence of unreacted monomers may result in degradation of the polymeric network, decreasing the strength and longevity of the bond. In the present study, Adper Scotchbond 1XT and Ambar performed significantly better than Prime&Bond NT.

One year effect of chlorhexidine on bonding of fibre-reinforced composite root canal post to dentine - Uncorrected Proof

2012-05-14

Abstract: Objectives: Chlorhexidine preserves the long-term bonding between composite restorations and coronal dentine. Our aim was to evaluate the long-term effect of chlorhexidine on attachment of fibre-reinforced composite (FRC) root canal posts to root canals. We hypothesized that chlorhexidine would not negatively affect the bond strength in aged specimens.Methods: Root canals of 40 human extracted third molars were prepared for post cementation with each post systems’ own burs. Four commercially available FRC posts (Glassix, D.T. Light-Post, Unicore, everStickPOST) were cemented with three different cements (Duo-link, PermaFlo DC, RelyX Unicem). After etching, except with self-adhesive RelyX Unicem, the post spaces were irrigated either with 2% chlorhexidine (Consepsis) or physiological saline for 60s. The roots (n=5 per group) were cut into 2mm thick dentine discs. The discs were stored in artificial saliva for one year. The bond strength was measured with the push-out method, and the failure mode was evaluated with a stereomicroscope.Results: Unicore with PermaFlo DC and everStickPOST with RelyX Unicem demonstrated significantly higher bond strength values both with and without chlorhexidine. After one year of storage chlorhexidine application improved the bond strength with D.T. Light-Post/Duo-link. With other posts and cements chlorhexidine application did not affect the bond strength.Conclusion: 2% chlorhexidine did not negatively affect the long-term bond strength of any material tested.Clinical significance: Irrigation of root canals with chlorhexidine, as indicated to prevent root canal infection during post placement, does not interfere with post bond strength when FRC posts are used.

Corrigendum to “Association between periodontitis and systemic bone mineral density in Japanese community-dwelling postmenopausal women” [J. Dent. 40 (2012) 304–311] - Uncorrected Proof

Osamu Takahashi, Akihiro Yoshihara, Kazutoshi Nakamura, Hideo Miyazaki — 2012-05-10

The authors regret However, we regret to inform you that we have found a misquotation in our report.

Niobium pentoxide as a novel filler for dental adhesive resin - Uncorrected Proof

2012-05-07

Abstract: Objectives: The purpose of this study was to develop an adhesive resin with incorporation of niobium pentoxide and evaluate its properties.Methods: Niobium pentoxide was characterised by X-ray diffraction, surface area, particle size, micro-Raman, scanning electron microscopy and the effectiveness of silanisation process by Fourier Transform Infrared (FTIR). An experimental adhesive resin was formulated with 0, 5, 10 and 20wt% Nb2O5. The formulated adhesive resins were evaluated based on microhardness, degree of conversion, radiopacity and interface (resin/dentine) characterisation by micro-Raman.Results: The particles used in this study presented a monoclinic crystalline phase with typical chemical groups and micrometre mean size. Microhardness and radiopacity increased with higher amounts of Nb2O5, and the particles were able to penetrate into the hybrid layers.Conclusions: Therefore, Nb2O5 may be an alternative for polymer-based biomaterials.Clinical significance: Niobium pentoxide could be used to produce adhesive resins with enhanced properties.

Assessment of perceptibility and acceptability of colour difference of denture teeth - Corrected Proof

2012-05-03

Abstract: Objectives: To assess the colour difference values that represent the perceptibility and acceptability thresholds of denture teeth.Methods: Eighteen interchangeable right upper central incisors denture teeth were selected to have colour difference values from representative left upper central incisor denture tooth in a range of 0.4–11.4 ΔE* units measured with a spectrophotometer (CM 2600d, Minolta Konica, Japan). These teeth were placed in an artificial dental arch in a phantom head. Under controlled conditions, a total of 80 observers divided into 4 groups (technicians, nurses, dentists and researchers) were asked to report the perceptibility and acceptability of each of the colour difference values. The findings was then analysed using logistic regression for determining the perceptible and acceptable thresholds of dental colour differences.Results: The determined colour difference values at which 50% of all observers could detect a colour difference (50:50 probability) was 1.9 ΔE* units with a 95% confidence interval and ranged from 1.7 ΔE* units to 2.1 ΔE* units. The determined colour difference value at which 50% of all observes preferred to replace the tooth because of unacceptable colour difference (50:50 probability) was 4.2 with a 95% confidence interval that ranged from 3.9 ΔE* units to 4.7 ΔE* units.Conclusions: Within the limitation of this study, the following conclusions were made:Clinical significance: When shade matching artificial denture teeth to natural teeth, 50:50 perceptibility (1.9 ΔE* units) and acceptability (4.2 ΔE* units) thresholds are used to compare colour difference values.The technicians group displayed lower perceptibility and acceptability limits than other observers.

Can a soda-lime glass be used to demonstrate how patterns of strength dependence are influenced by pre-cementation and resin-cementation variables? - Uncorrected Proof

Paul Hooi, Owen Addison, Garry J.P. Fleming — 2012-05-03

Abstract: Objectives: To determine how the variability in biaxial flexure strength of a soda-lime glass analogue for a PLV and DBC material was influenced by precementation operative variables and following resin-cement coating.Methods: The flexural modulus of a transparent soda-lime glass was determined by longitudinally sectioning into rectangular bar-shaped specimens and the flexural moduli of three resin-based materials (Venus Flow, Rely-X Veneer and Clearfil Majesty Posterior) was also determined. Discshaped soda-lime glass specimens (n=240) were divided into ten groups and were alumina particle air abraded, hydrofluoric (HF) acid-etched and resin-cement coated prior to biaxial flexure strength testing. Sample sets were profilometrically evaluated to determine the surface texture. One-way analyses of variance (ANOVA) and post hoc all paired Tukey tests were performed at a significance level of P<0.05. The mean biaxial flexure strengths were plotted against resin-coating thickness and a regression analysis enabled estimation of the ‘actual’ magnitude of strengthening.Results: The mean three-point flexural modulus of the soda-lime glass was 40.0 (1.0)GPa and the Venus Flow, Rely-X Veneer and Clearfil Majesty Posterior were 3.0 (0.2)GPa, 6.0 (0.2)GPa and 14.8 (1.6)GPa, respectively. At a theoretical ‘zero’ resin-coating thickness an increase in biaxial flexure strength of 20.1% (63.2MPa), 30.8% (68.8MPa) and 36.3% (71.7MPa), respectively was evident compared with the control (52.6 (5.5)MPa).Conclusions: Disc-shaped specimens cut from round stock facilitated rapid fabrication of discs with uniform surface condition and demonstrated strength dependence was influenced by precementation parameters and resin-cementation variables.

Inhibition of erosive dissolution by sodium fluoride: Evidence for a dose–response - Corrected Proof

A.J. White, S.B. Jones, M.E. Barbour, D.R. Churchley, L.H. Gracia, G.D. Rees — 2012-04-30

Abstract: Objectives: The aim of this study was to investigate the protective effects of sodium fluoride solutions and commercial mouthrinses on hydroxyapatite (HA) dissolution in citric acid in vitro, with and without a salivary pellicle.Methods: A rapid-throughput HA solubility-reduction model was employed in which HA dissolution was quantified using ion chromatography. Two HA substrates were selected, a high-resolution powder and 80μm diameter beads, and studied in the presence and absence of a salivary pellicle (pooled human saliva, 2h). Immediately prior to acid exposure, substrates were exposed to one of a number of pre-treatments that included aqueous fluoride (F−) solutions and commercially available mouthrinses with F− concentrations of 0–450μg/g (as NaF). Dissolution reduction was calculated relative to a deionised water negative control.Results: For aqueous solutions and mouthrinses, a fluoride dose–response was observed with a plateau around 100μg/g F− for both HA substrates, with or without pellicle. Concentrations as low as 10μg/g F− significantly reduced HA dissolution. The HA substrate had little impact on the fluoride dose–response, and the fluoride was equally effective in the presence of a pellicle as in its absence.Conclusions: Fluoride significantly reduced HA dissolution at concentrations of 10μg/g and higher. A fluoride dose–response was seen at low concentrations. This study illustrates the use of a powerful rapid-throughput HA solubility-reduction model for investigating HA dissolution in citric acid in the presence of dissolution inhibitors.Clinical significance: A single exposure to fluoride solutions with fluoride concentrations and exposure time representative of brushing or rinsing with mainstream oral care products was shown to significantly inhibit HA dissolution under conditions relevant to dental erosion. A similar efficacy was observed in the presence and absence of salivary pellicle.

Optical properties of enamel and translucent composites by diffuse reflectance measurements - Corrected Proof

Rong Li, Xiao Ma, Shanshan Liang, Yue Sa, Tao Jiang, Yining Wang — 2012-04-30

Abstract: Objectives: The aim of this study was to evaluate the optical properties of natural enamel and translucent composites by diffuse reflectance measurements and Kubelka–Munk's theory.Methods: Twenty natural enamel slabs and 80 composite replicas using four brands of translucent composites (Gradia Direct, Venus™, Brilliant New line and Beautiful II; n=20) were evaluated at thicknesses of 1.0mm. The spectral distributions of enamel and composites were measured by means of a reflectance spectrophotometer. Optical constants including scattering coefficient (S), absorption coefficient (K), light reflectivity (RI) and infinite optical thickness (X∞) were calculated from the spectral reflectance data using Kubelka's equations. Paired t-tests were performed to evaluate the differences of optical constants (S, K, RI and X∞) between natural enamel and composites.Results: The optical constants S and K decreased with increasing wavelength, while RI and X∞ increased with increasing wavelength within the visible spectrum. The values of enamel were in the range of the optical constants of these composites within the visible spectrum. However, there were significant differences of optical constants (S, K, RI and X∞) between enamel and translucent composites (p<0.05).Conclusions: The optical constants of translucent composites were not completely consistent with that of natural enamel. In addition, the optical properties of these translucent composites varied with the brands of the composites.

Effects of common beverage colourants on colour stability of dental composite resins: The utility of a thermocycling stain challenge model in vitro - Corrected Proof

Yan-Fang Ren, Lin Feng, Diana Serban, Hans S. Malmstrom — 2012-04-30

Abstract: Objectives: To study the colour stability of dental composite resins using a thermocycling stain challenge model accounting for the complex effects of oral environment and tooth brushing.Methods: Composite resin discs were made from Filtek Supreme Ultra (FiltekSU), TPH3 and Renamel, and subjected to thermocycling challenges in warm coffee (55°C/pH 5.2) and a cold tea and fruit juice mixtures (5°C/pH 3.6) for a total of 1000 cycles with 30seconds dwell time in each solution per cycle. Colour was assessed in the CIELAB colour space using a Crystaleye dental spectrophotometer before and after thermocycling, and after brushing vigorously for 3min. The thermocycling stain challenge was repeated for a second 1000 cycles and the discs were brushed again. Colour changes were compared among the 3 groups using Kruskal–Wallis test.Results: All 3 groups showed statistically significant colour changes after stain challenge, with ΔE* as 5.74 for FiltekSU, 3.21 for TPH3 and 2.52 for Renamel. Colour change was more significant in FiltekSU than in TPH3 and Renamel (p<0.05). After brushing, colour recovered mostly to its original CIELAB values in TPH3 and Renamel but less so in FiltekSU. The second round of thermocycling stain challenge resulted in colour changes in FiltekSU that largely could not be removed by vigorous brushing.Conclusions: Colour stability of FiltekSU is inferior to that of TPH3 and Renamel. The thermocycling stain challenge model can potentially differentiate surface staining that can be removed by brushing from true discolouration of the material that is refractory to oral hygiene procedures.

A study to determine the added value of 740 screening panoramic radiographs compared to intraoral radiography in the management of adult (>18 years) dentate patients in a primary care setting - Corrected Proof

Michael N. Rushton, Vivian E. Rushton — 2012-04-30

Abstract: Objectives: To measure the added value of panoramic radiography in new dentate patients attending for routine treatment.Methods: Thirty-seven general dental practitioners using panoramic radiographs routinely were recruited. Twenty dentate patients were identified prospectively by each participating dentist if they were new to the practice, attending for an examination and requesting any treatment deemed necessary. A panoramic radiograph was taken with appropriate intraoral radiographs in line with national guidelines. Each dentist completed a radiological report for the panoramic radiograph only and these 20 reports were forwarded to the researchers along with the 20 panoramic radiographs, their accompanying bitewing and periapical radiographs and twenty completed clinical assessment sheets.Results: 740 panoramic, 1418 bitewing and 325 periapical radiographs were assessed by the researchers. Only 32 panoramic films provided any additional diagnostic value when compared to intraoral films when guidelines had been observed resulting from the poor technical and processing quality of the accompanying intraoral films. Assessment of the number of caries and periapical lesions and the degree of periodontal bone loss from the intraoral films provided a greater diagnostic yield at the p<0.001 level of significance. The research found that dentists underestimated the number of caries lesions present and level of periodontal bone loss when compared to the researchers but overestimated the presence of periapical pathology, at the level of significance at p<0.001.Conclusions: The study found that there was no support for the use of panoramic radiographs in routine screening as there was no net diagnostic benefit to the patient.

Internal adaptation, marginal accuracy and microleakage of a pressable versus a machinable ceramic laminate veneers - Corrected Proof

Moustafa Nabil Aboushelib, Waleed AbdelMeguid Elmahy, Mohammed Hamed Ghazy — 2012-04-30

Abstract: Objectives: The aim of this study was to evaluate the internal adaptation and marginal properties of ceramic laminate veneers fabricated using pressable and machinable CAD/CAM techniques.Materials and methods: 40 ceramic laminate veneers were fabricated by either milling ceramic blocks using a CAD/CAM system (group 1 n=20) or press-on veneering using lost wax technique (group 2 n=20). The veneers were acid etched using hydrofluoric acid, silanated, and cemented on their corresponding prepared teeth. All specimens were stored under water (37°C) for 60days, then received thermocycling (15,000 cycles between 5 and 55°C and dwell time of 90s) followed by cyclic loading (100,000 cycles between 50 and 100N) before immersion in basic fuchsine dye for 24h. Half of the specimens in each group were sectioned in labio-lingual direction and the rest were horizontally sectioned using precision cutting machine (n=10). Dye penetration, internal cement film thickness, and vertical and horizontal marginal gaps at the incisal and cervical regions were measured (α=0.05).Results: Pressable ceramic veneers demonstrated significantly lower (F=8.916, P<0.005) vertical and horizontal marginal gaps at the cervical and incisal margins and lower cement film thickness (F=50.921, P<0.001) compared to machinable ceramic veneers. The inferior marginal properties of machinable ceramic veneers were associated with significantly higher microleakage values.Conclusions: Pressable ceramic laminate veneers produced higher marginal adaptation, homogenous and thinner cement film thickness, and improved resistance to microleakage compared to machinable ceramic veneers.Clinical significance: The manufacturing process influences internal and marginal fit of ceramic veneers. Therefore, dentist and laboratory technicians should choose a manufacturing process with careful consideration.

Amalgam or composite resin? Factors influencing the choice of restorative material - Uncorrected Proof

M.B. Correa, M.A. Peres, K.G. Peres, B.L. Horta, A.D. Barros, F.F. Demarco — 2012-04-30

Abstract: Objectives: This study aimed to investigate the patient and tooth factors associated with selection of restorative material in direct posterior restorations in young adults from a population-based birth cohort.Methods: A representative sample (n=720) of all 5914 births occurring in Pelotas in 1982 were prospectively investigated, and posterior restorations were assessed in 2006, when the patients were 24 years old. Tooth-related variables (individual level) included restorative material (amalgam or composite), type of tooth, size of cavity, and estimated time in mouth. Data regarding demographic and socio-economic characteristics, oral health, and service utilization patterns during the life course were also assessed (contextual level).Results: Logistic Regression Multilevel models showed that individuals who have accessed dental services by private insurance by age 15 [odds ratio (OR)=1.66 (0.93–2.95)] and who had a higher dental caries index at age 15 (high DMFT tertile) [OR 2.89 (1.59–5.27)] presented more amalgam restorations in the posterior teeth. From tooth-level variables, the frequency of amalgams decreases with increasing number of surfaces enrolled in the cavity preparation (p<0.001) and was almost 5 times greater in molars than in premolars.Conclusions: The present findings suggest that variables related to type of dental service, dental caries (higher DMFT index), and cavity characteristics (tooth type, size) determine the choice of dentists for restorative materials. Other individual characteristics such as demographic and socioeconomic status have not influenced this choice.Clinical significance: This is the first population-based study that assesses the determinant factors for the choice of dentists for composite or amalgam in posterior direct restorations, showing that, independently of socioeconomic and demographic characteristics, type of payment of dental services and clinical factors are associated with this choice.

White and pink—Emulating nature and beyond - Uncorrected Proof

Ronald E. Goldstein, Rade D. Paravina — 2012-04-26

Certainly one of the most difficult aesthetic problems occur when either the gingival papilla or the alveolar ridge has receded or been lost due to a number of causes. To begin with, the gingival papilla in its ideal form helps to define the size and shape of the teeth. Failure to recreate a missing papilla can drastically alter the tooth contour and thus the entire smile can suffer.

Development of polarization dental imaging modality and evaluation of its clinical feasibility - Uncorrected Proof

Eunji Kim, Taeyoon Son, Yoon Lee, Byungjo Jung — 2012-04-26

Abstract: Objectives: In the evaluation of tooth colour, the specular reflection caused by roughness or saliva on the tooth surface may cause artefacts in image analysis. In this study, a polarization dental imaging modality (PDIM) was developed to obtain cross-polarized images and, therefore, to address the problem of specular reflection. Its clinical validity was evaluated by performing 3 studies of shade tab selection for implant, plaque distribution detection, and evaluation of tooth whitening.Methods: In vivo human tooth and shade guide colour images were obtained, and the minimum colour difference between them was calculated for the best colour matching shade tab selection. A dental plaque disclosing agent was used to differentiate plaque regions on teeth, and plaque distribution was detected by applying the K-means algorithm. In vivo human teeth were treated with a commercial tooth whitening gel, and tooth whitening was quantitatively evaluated using the PDIM images.Results: The PDIM produced repeatable glare-free tooth colour images by effectively removing the specular reflection from the tooth surface. The cross-polarized tooth images were successfully utilized for shade guide selection, plaque detection, and tooth whitening by minimizing artefacts in the quantitative image analysis. The PDIM could simultaneously provide both qualitative and quantitative assessment of the tooth condition in clinical diagnosis.Conclusions: The clinical feasibility of the PDIM was successfully verified in 3 clinical studies by showing its clinical efficacy as a new imaging modality.

Ageing of silorane-based and methacrylate-based composite resins: Effects on translucency - Corrected Proof

2012-04-26

Abstract: Objectives: Verify if media and time of storage affect the translucency of a silorane-based composite (Filtek P90) compared to two methacrylate-based composites (Z350 and ROK), and compare two methods of translucency evaluation.Methods: Specimens were divided into two groups (n=7) according to the storage media (deionized water or red wine). With a spectrophotometer (SP60) in reflectance mode, the CIE L*a*b* parameters and opacity percentage readings were conducted at baseline, 24h, 30 days, and 180 days. Data were analyzed using two-way repeated measures ANOVA and Tukey (p<0.05). Pearson correlation measured the relationship between translucency parameter and opacity percentage.Results: When stored in water, P90 showed an increase, whereas Z350 decreased in translucency. ROK did not exhibit any tendency over time. When stored in wine, the translucency of all materials decreased. A negative relationship was found between translucency parameter and opacity percentage. When stored in water, the a* values for P90 decreased, whereas Z350 and ROK showed values increasing over time. When stored in wine, the L* parameter tended to decrease over time, an effect that was less intense for P90. Moreover, the b* parameter for P90 decreased, whereas methacrylate-based composites increased over time.Conclusions: P90 was more stable in red wine than the other materials and became more translucent in water whether metacrilate-based materials became more opaque. Both media as well as storage time affected the translucency of the materials tested. Translucency could be measured with both methods tested.Clinical significance: Silorane-based composites seemed to be more stable than methacrylate-based composites in red wine and became more translucent over time in water, which was different than methacrylate-based composites. More studies are needed to clarify silorane-based composites performance.

Assessment of laminate technique using glass ionomer and resin composite for restoration of root filled teeth - Corrected Proof

N.A. Taha, J.E. Palamara, H.H. Messer — 2012-04-23

Abstract: Objective: To evaluate the open laminate technique using glass ionomer cements (GIC) in association with a low shrink composite for restoring root filled premolars.Methods: Extensive MOD cavities plus endodontic access and root filling were performed in intact extracted maxillary premolars. Three restoration types were evaluated: (1) resin composite alone; (2) resin-modified GIC (RM-GIC) open laminate plus resin composite; (3) conventional GIC open laminate plus resin composite (n=8 for all groups and tests). Three tests were conducted to assess restorations: (A) inward cusp deflection during light curing, using DCDTs; (B) fracture strength using a ramped oblique load at 45° to the long axis in a servohydraulic testing machine in comparison with intact and unrestored teeth; (C) proximal marginal leakage using methylene blue dye and the effect of thermocycling. Data were analysed using 1-way ANOVA for cuspal deflection and fracture strength and Fisher's exact test for leakage.Results: Laminate restorations resulted in significantly less cuspal deflection compared with resin composite (4.2±1.2μm for RM-GIC and 5.1±2.3μm for conventional GIC vs. 12.2±2.6μm for composite, P<0.001). Fracture strength was not significantly different among all groups. Failure with all restorations was predominantly adhesive at the tooth-restoration interface. The two laminate groups showed significantly better marginal seal than composite alone, but sealing ability of conventional GIC deteriorated after thermocycling.Conclusions: Laminate restoration of root filled teeth had beneficial effects in terms of reducing cuspal deflection and marginal seal, with acceptable fracture strength.

Measuring patient-based outcomes: Is treatment satisfaction associated with oral health-related quality of life? - Corrected Proof

Pierre-Luc Michaud, Pierre de Grandmont, Jocelyne S. Feine, Elham Emami — 2012-04-23

Abstract: Objectives: To evaluate the level of association between patients’ denture satisfaction and oral health-related quality of life (OHRQoL) in edentate patients, and to identify the determinants of satisfaction that best predict OHRQoL. The effects of time and treatment type were also assessed.Methods: Data from 255 edentate elders who participated in a randomised clinical trial were used. OHRQoL ratings were gathered using the Oral Health Impact Profile (OHIP-20) questionnaire. The McGill Denture Satisfaction Instrument was used to assess satisfaction with treatment (mandibular conventional denture or implant overdenture). Outcomes were measured prior to treatment, then 6 and 12 months after delivery of the new prostheses. Simple linear and multiple linear regression analyses were performed to statistically analyse the relationship.Results: When the combined effect of all factors was assessed, only two variables of denture satisfaction ratings were significantly associated with OHRQoL: chewing ability (P=.005) and oral condition (P=.002). These two variables explained 46.4% of the variance in the OHIP change scores. This association varied with time, but the variables of importance remained the same. Type of treatment, gender, age and other socio-demographic variables were not significantly associated with improvement in OHRQoL once their effects were combined with denture satisfaction ratings.Conclusions: Within the limitations of this study, a highly positive association exists between oral health-related quality of life and denture satisfaction. Chewing ability and oral condition are the determinants of denture satisfaction best associated with OHRQoL, predicting 46.4% of its improvement following a treatment.

Effect of fluoride sustained slow-releasing device on fluoride, phosphate and calcium levels in plaque biofilms over time measured using ion chromatography - Corrected Proof

Hani Abudiak, Colin Robinson, Monty S. Duggal, Simon Strafford, K. Jack Toumba — 2012-04-23

Abstract: Objectives: To determine whether there are any differences in fluoride (F), calcium (Ca) or phosphate (PO4) concentrations in natural plaque biofilms between the upper right and left quadrants using a fluoride sustained slow-releasing device (FSSRD) placed in the upper right quadrant after 7 and 21 days. To report and validate a new methodology in measuring very low concentrations of F in dental plaque and saliva using ion chromatography.Methods: Twenty-one participants were divided into two groups with 11 participants in group one and 10 in group two. Each participant had a FSSRD attached to the upper right second permanent molar and two plaque generating devices (PGDs) attached to the upper right and left first permanent molars. The PGDs were recovered after 7 days in group one and 21 days in group two.Results: At both 7 and 21 days (right, left), F (1.081±1.517ppm, 0.736±0.840ppm) and (0.459±0.888ppm, 0.203±0.139ppm), PO4 (1053±533ppm, 654±246ppm) and (865±1099ppm, 474±304ppm) and Ca (136±132ppm, 74±36ppm) and (130±109ppm, 77±24ppm), were higher in the quadrant containing the FSSRD but not significantly so (p>0.05). Fluoride and PO4 fell in both quadrants between 7 and 21 days, though not significantly.Conclusions: Intriguingly while not statistically significant, 21 day plaque contained less fluoride than those investigated after 7 days. While the data was not statistically significant, it seems possible that F, Ca and PO4 accumulated around the device to a limited extent but were washed away fairly quickly and distributed around the oral cavity.Clinical importance: The FSSRD was found to reduce dmfs/DMFS by 76% and raise salivary F levels by ∼10 folds. This device is very helpful in reducing dental decay where compliance is impaired such as in patients with special needs. This study further investigates the anti-cariogenic effect of this device.

Swallowing threshold parameters of subjects with shortened dental arches - Corrected Proof

C.M. Kreulen, D.J. Witter, F.A. Tekamp, A.P. Slagter, N.H.J. Creugers — 2012-04-23

Abstract: Objectives: To quantify swallowing threshold parameters of subjects with a moderate shortened dental arch dentition (SDA: missing molar teeth, but premolar teeth in occluding position and uninterrupted anterior regions) compared to subjects with a complete dental arch dentition (CDA).Methods: Fourteen females with SDA (3–4 occlusal premolar units) and 14 females with CDA were instructed to chew silicone test ‘food’ (cubic particles with a total volume of 3cm3). They spit it out the moment they felt the urge to swallow and the pulverized particles were collected. Swallowing threshold parameters were number of chewing cycles, time until ‘swallowing’, and median particle size of the pulverized particles as determined by sieving the food. Chewing tests were performed twice and outcomes were averaged.Results: The number of chewing cycles until ‘swallowing’ of subjects with SDA was approximately 1.7 times (p<0.005) that of the controls and this took approximately 1.6 times more time (p<0.01). The median particle size until ‘swallowing’ did not differ significantly between the groups, but demonstrated large individual differences. Regression analyses indicated that the ratio of median particle size until ‘swallowing’ of SDA and CDA becomes progressively unfavourable for SDA with increasing numbers of chewing cycles.Conclusions: Subjects with SDA pulverized test ‘food’ particles to sizes comparable to subjects with CDA, but chewed longer with more chewing cycles until ‘swallowing’. Higher numbers of chewing cycles were associated with increasing difference between SDA and CDA regarding the median particle size until ‘swallowing’.Clinical significance: Compared to subjects with CDA, subjects with moderate SDA pulverize test food particles to comparable size by chewing longer before “swallowing”. Therefore, overloading the digestive system by swallowing courser food particles is unlikely in SDA. Consequently, replacement of absent molars just to optimize chewing function is not advised.

The effects of light on bleaching and tooth sensitivity during in-office vital bleaching: A systematic review and meta-analysis - Corrected Proof

Li-Bang He, Mei-Ying Shao, Ke Tan, Xin Xu, Ji-Yao Li — 2012-04-23

Abstract: Objective: To evaluate the influence of light on bleaching efficacy and tooth sensitivity during in-office vital bleaching.Data sources: We performed a literature search using Medline, EMBASE and Cochrane Central up to September 2011.Study selection: All randomised controlled trials (RCTs) or quasi-RCTs comparing the light-activated bleaching system with non-activation bleaching system were included. Reports without clinical data concerning bleaching efficacy or tooth sensitivity were excluded.Results: Eleven studies were included in the meta-analysis. A light-activated system produced better immediate bleaching effects than a non-light system when lower concentrations of hydrogen peroxide (15–20% HP) were used (mean difference [MD], −1.78; 95% confidence interval [CI]: [−2.30, −1.26]; P<0.00001). When high concentrations of HP (25–35%) were employed, there was no difference in the immediate bleaching effect (MD, −0.39; 95% CI: [−1.15, 0.37]; P=0.32) or short-term bleaching effect (MD, 0.25; 95% CI: [−0.47, 0.96]; P=0.50) between the light-activated system and the non-light system. However, the light-activated system produced a higher percentage of tooth sensitivity (odds ratio [OR], 3.53; 95% CI: [1.37, 9.10]; P=0.009) than the non-light system during in-office bleaching.Conclusions: Light increases the risk of tooth sensitivity during in-office bleaching, and light may not improve the bleaching effect when high concentrations of HP (25–35%) are employed. Therefore, dentists should use the light-activated system with great caution or avoid its use altogether. Further rigorous studies are, however, needed to explore the advantages of this light-activated system when lower concentrations of HP (15–20%) are used.

Applicability of CIELAB/CIEDE2000 formula in visual color assessments of metal ceramic restorations - Accepted Manuscript

BT. Xu, B. Zhang, Y. Kang, YN. Wang, Q. Li — 2012-04-23

Abstract: Objectives: To investigate the applicability of color-difference formula (CIELAB or CIEDE2000) in visual color assessments of metal-ceramic specimens in small color-difference ranges.Methods: Metal-ceramic specimens using mixture of gradient ratio porcelain powders were fabricated to create a color pool. Color differences of specimen pairs were calculated using the CIELAB (ΔE*ab) and CIEDE2000 (ΔE00). A questionnaire, composed of 1 target and 3 enactment specimens, was designed. For formula-determination, the enactment specimen with the minimum ΔE to the target specimen was registered as FS. For visual-assessment, twenty participants were asked to finish the questionnaire by choosing the most color-matched enactment specimen to the target. The percentage of the FS been selected (PFS) was calculated, which was used to represent the consistence of formula-determination and visual-assessment. Binomial Tests were used to compare the differences between PFS values and 33% (the randomized probability of the FS been selected was one out of three, approximate 33%). Regression analysis was used to determine the correlation between ΔE*ab and ΔE00 values.Results: A linear regression equation was drawn as ΔE00=-0.049+0.619×ΔE*ab. There were no significant differences between PFS values and 33% within the range of ΔE*ab<2.0, whereas PFS values were significantly higher than 33% when ΔE*ab>2.0 (P<0.001). There was a tendency of selecting the enactment specimens with lower L* values and higher b* or C′ values, within the range of 1.0<ΔE*ab<2.0.Conclusions: CIE color-difference formulas were not applicable for visual color assessments of metal-ceramic specimens within the color-difference range of ΔE*ab<2.0.

The antifungal properties of chlorhexidine digluconate and cetylpyrinidinium chloride on oral Candida - Corrected Proof

A.R. Fathilah, W.H. Himratul-Aznita, A.R.N. Fatheen, K.R. Suriani — 2012-04-20

Abstract: Introduction: C. tropicalis and C. krusei have emerged as virulent species causing oral infections. Both have developed resistance to commonly prescribed azole antifungal agents.Objective: The study aimed to determine the effect of mouth rinses containing chlorhexidine digluconate (CHX), cetylpyridinium chloride (CPC) and their combination (CHX–CPC) on the growth of these strains.Methods: The minimal inhibition concentrations (MIC) of the mouth rinses were determined. The growth curves of the strains produced under the mouth rinse-treated and untreated conditions, as well as alterations to the morphology of the growth colonies and cells following the treatments were compared and analysed.Results: The MICs of CPC compared to CHX mouth rinses were found to be lower for both Candida sp. In the mixed formulation, CPC doubled the inhibitory effect of CHX towards both Candida sp., while CHX quadrupled the activity of CPC towards C. tropicalis. The growth colonies also appeared coarse, wrinkled and dried.Conclusion: The profound effects shown may suggest the fungicidal activities of the mouth rinses incorporated with CHX, CPC or their combination on both C. tropicalis and C. krusei. Gargling using mouth rinses with such fungicidal activity would enhance a rapid reduction in the candidal population of patients with fungal infection.

Hereditary dentine diseases resulting from mutations in DSPP gene - Corrected Proof

Izabela Maciejewska, Ewa Chomik — 2012-04-20

Abstract: Objectives: This review groups the newest results of molecular analyses of DSPP gene for patients diagnosed either with dentinogenesis imperfecta type II/III or dentine dysplasia and tries to link the phenotypes with specific mutations in the DSPP gene.Data: The review includes biochemical data introducing a specificity of DSPP protein which justifies it as a critical factor for dentine mineralization and maturation. The majority of the review analyzes mutations in the DSPP gene which result in phenotypes of dentinogenesis imperfecta types II or/and III or dentine dysplasia.Sources: An electronic search was conducted in the databases of Pub Med and supplemented by manual study of relevant references.Study selection: 52 out of 108 references were finally selected for the review based on the novelty and/or originality of data.Conclusion: Hereditary dentine disorders dentinogenesis imperfecta type II/III and dentine dysplasia are currently proposed to be one disease with distinct clinical manifestations reflecting various mutations in the same DSPP gene. For years both disorders were linked exclusively to mutations in the DSP code but a growing number of papers describe mutations which manifest a similar phenotype but are localized in the strongly repetitive sequence of the 3′ terminus of the DSPP which codes DPP protein. Our search suggests that the localization of mutation in the sequence of the DSPP gene might result in a different phenotype due to the diverse cellular fate of the mutated protein. Thus comprehensive research on the cellular fate and processing of both normal and mutated DSPP is still required.

Shear bond strength of porcelain laminate veneers to enamel, dentine and enamel–dentine complex bonded with different adhesive luting systems - Uncorrected Proof

Elif Öztürk, Şükran Bolay, Reinhard Hickel, Nicoleta Ilie — 2012-04-20

Abstract: Objectives: The aim of this study was to evaluate the shear bond strength of porcelain laminate veneers to 3 different surfaces by means of enamel, dentine, and enamel–dentine complex.Methods: One hundred thirty-five extracted human maxillary central teeth were used, and the teeth were randomly divided into 9 groups (n=15). The teeth were prepared with 3 different levels for bonding surfaces of enamel (E), dentine (D), and enamel–dentine complex (E–D). Porcelain discs (IPS e.max Press, Ivoclar Vivadent) of 2mm in thickness and 4mm in diameter were luted to the tooth surfaces by using 2 light-curing (RelyX Veneer [RV], 3M ESPE; Variolink Veneer [VV], Ivoclar Vivadent) and a dual-curing (Variolink II [V2], Ivoclar Vivadent) adhesive systems according to the manufacturers’ instructions. Shear bond strength test was performed in a universal testing machine at 0.5mm/min until bonding failure. Failure modes were determined under a stereomicroscope, and fracture surfaces were evaluated with a scanning electron microscope. The data were statistically analysed (SPSS 17.0) (p=0.05).Results: Group RV-D exhibited the lowest bond strength value (5.42±6.6MPa). There was statistically no difference among RV-D, V2-D (13.78±8.8MPa) and VV-D (13.84±6.2MPa) groups (p>0.05). Group VV-E exhibited the highest bond strength value (24.76±8.8MPa).Conclusions: The type of tooth structure affected the shear bond strength of the porcelain laminate veneers to the 3 different types of tooth structures (enamel, dentine, and enamel–dentine complex).Clinical significance: When dentine exposure is necessary during preparation, enough sound enamel must be protected as much as possible to maintain a good bonding; to obtain maximum bond strength, preparation margins should be on sound enamel.

The influence of long term water immersion on shear bond strength of amalgam repaired by resin composite and mediated by adhesives or resin modified glass ionomers - Corrected Proof

R. Pilo, J. Nissan, H. Shafir, G. Shapira, E. Alter, T. Brosh — 2012-04-16

Abstract: Objective: To assess the shear bond strength between amalgam and resin composite mediated by either multipurpose adhesive systems or RMGI when subjected to long term immersion in saline.Methods: Part I: Cylindrical specimens (6mm×6mm) composed of equal parts of sandblasted set amalgam (Oralloy) and composite (Z-100), with a thin layer of either Scotchbond Multipurpose, All Bond 2, Amalgam Bond Plus, High Q Bond Plus or Vitrebond in between were fabricated (n=100×5). Each group was divided into 3 subgroups, immersed in saline at 37°C for either 48h, 3 or 6months, followed by thermocycling (5000; 5/55°C) and shear bond strength testing (SBS). Part II: Identical specimens were fabricated with intermediary of either Ketac Cem, Fuji Lining LC, Rely X Luting, Fuji Plus or Meron Plus (n=100×5). Immersion periods, followed by thermocycling and SBS testing as in Part I.Two representative specimens from each subgroup were sectioned and inspected under SEM.Results: The two classes of intermediary agents yielded SBS which differed mainly in the 6months incubation period. While multipurpose adhesives provided SBS values of ∼9–10MPa RMGI provided higher SBS of ∼16MPa. All Bond 2 and Amalgam Bond Plus exhibited deterioration of SBS during the 6month period as well as Rely X Luting. Gap sizes between 0.5 and 3μm exist between all intermediaries and the amalgam; on the other hand all intermediaries exhibit gap-free interfaces between the adhesives/RMGI and the composite.Conclusions: Vitrebond in particular and RMGIs in general can serve as an excellent coupler of resin composite to amalgam, providing a durable bond.

Assessment of early attrition using an ordinary flatbed scanner - Corrected Proof

Arie van’t Spijker, Cees M. Kreulen, Ewald M. Bronkhorst, Nico H.J. Creugers — 2012-04-16

Abstract: The aim of this study was to assess a two-dimensional method to monitor occlusal tooth wear quantitatively using a commercially available ordinary flatbed scanner.Materials and methods: A flatbed scanner, measuring software and gypsum casts were used. In Part I, two observers (A and B) independently traced scans of marked wear facets of ten sets of casts in two sessions (test and retest). In Part II, three other sets of casts were duplicated and two observers (C and D) marked wear facets and traced the scanned images independently. Intra- and inter-observer agreement was determined comparing measured values (mm2) in paired T-tests. Duplicate measurement errors (DME) were calculated.Results: In Part I the test and retest values (10 casts, 218 teeth) of observer A and B did not differ significantly (A: p=0.289; B: p=0.666); correlation coefficients were 0.998 (A) and 0.999 (B). “Tracing wear facets” showed a DME of 0.30mm2 for observer A and 0.15mm2 for observer B. In Part II, assessment of 70 teeth resulted in correlation coefficients of 0.994 for observer C and 0.997 for observer D; no differences between test and retest values were found for C (p=0.061), although D differed significantly (p=0.000). The DME for “marking and tracing wear facets” was 0.39mm2 (C) and 0.27mm2 (D). DME for inter-observer agreement were 0.45mm2 (test) and 0.42mm2 (re-test).Conclusion and clinical relevance: We conclude that marking and tracing of occlusal wear facets to assess occlusal tooth wear quantitatively can be done accurately and reproducibly.

An in situ study investigating dentine tubule occlusion of dentifrices following acid challenge - Corrected Proof

2012-04-06

Abstract: Objectives: To investigate the dentine occlusion and acid resistance of dentifrices developed to treat dentine hypersensitivity.Methods: This was a single centre, single blind, randomised, split mouth, four treatments, two period crossover, in situ study in healthy subjects. Subjects wore buccal intra-oral appliances each fitted with four dentine samples over four consecutive days with one study product applied per appliance; 8% strontium acetate in silica base, 1040ppm sodium fluoride (Sensodyne® Rapid Relief), 8% arginine, calcium carbonate, 1450ppm sodium monofluorophosphate (Colgate Sensitive Pro-Relief®), 1450ppm sodium fluoride (control paste) and water. On days 3 and 4, two agitated grapefruit juice challenges (ex vivo) occurred for 1min. At the end of each treatment day 1 dentine sample was removed from each appliance for scanning electron microscopy (SEM). The extent of tubule occlusion was measured using an examiner-based visual scoring index (three trained examiners).Results: In total, 28 subjects ((12 males and 16 females with a mean age of 34.7 years (SD 8.41 years)) completed the study. On day 2, both test dentifrices demonstrated significantly better dentine tubule occlusion than water (p<0.0001) and control paste (8% strontium p=0.0003 and 8% arginine p=0.0019). After 3 and 4 days of twice daily brushing with acid challenges on days 3 and 4 the strontium-based dentifrice demonstrated significantly better dentine occlusion than all other treatments (p<0.0001).Conclusions: Strontium acetate and arginine-based dentifrice result in statistically significant dentine tubular occlusion compared to controls, but the arginine-based dentifrice is more susceptible to acid challenge.Clinical significance: Erosive beverages are an important aetiology in DH by exposing dentine tubules. Their consumption has increased significantly over the past decade in the UK. This 4-day in situ study investigated the properties of commercially available dentifrices designed to occlude dentine tubules and their resistance to an agitated acid challenge.

Quantification of residual dentine thickness following crown preparation - Corrected Proof

Graham R. Davis, Rabab A. Tayeb, Kevin G. Seymour, George P. Cherukara — 2012-04-05

Abstract: Objectives: Pulpal response to tooth preparation is a major concern in fixed prosthodontics. Research has suggested that 2mm or more of remaining dentine is critical in protecting the pulp following tooth preparation. However, clinicians have no means of knowing dentine thickness either before or after preparation and therefore lack feedback about this important aspect of preparation quality. The aim of this project was to develop a method for measuring local dentine thickness following tooth preparation for metal ceramic crowns, in vitro, which could be used as a tool to evaluate preparation technique and instrumentation.Methods: Microtomography (XMT or micro-CT) scans were taken of extracted teeth before and after crown preparation. Local dentine thickness was defined for every voxel within the 3D tooth image as the sum of distances from that voxel to the pulp and to the anatomical surface. The method also allows the thickness of material removed to be quantified. Three-dimensional colour-coded maps of dentine thickness were generated, and the distributions of dentine thickness throughout the teeth were analysed. This was tested by a single operator on sixteen extracted upper central incisors.Results: This method enabled clear visualisation and analysis of residual dentine thickness. In the trial, it revealed consistent over-prepared regions along the labial proximal line angles which, in a clinical case, could affect subsequent tooth and restoration longevity. All but one of the prepared teeth had regions with a residual dentine thickness of less than 1.5mm, in 6 it was less than 1.0mm and in 3 of these it was less than 0.5mm.Conclusion: Although ex vivo, this method can be used as a research tool to look for patterns of over- or under-preparation, leading to possible modification of technique, instrumentation and, or crown design.Clinical significance: It is not currently possible for clinicians to know the thickness of residual dentine following crown preparation, a key factor in long term outcome. The described method of quantifying and visualising this thickness allows preparation techniques and instrumentation to be evaluated in vitro, leading to prospective improvements in clinical procedures.

Degree of conversion and microhardness of TPO-containing resin-based composites cured by polywave and monowave LED units - Corrected Proof

Ario Santini, Vesna Miletic, Michael D. Swift, Mark Bradley — 2012-04-05

Abstract: Objectives: To determine the degree of conversion (DC) and Knoop microhardness (KHN) of resin-based composites (RBCs) containing trimethylbenzoyl-diphenylphosphine oxide (TPO) cured by polywave or monowave LED light-curing units (LCUs).Methods: Three groups (each n=5) of Tetric EvoCeram (Ivoclar Vivadent), Vit-l-escence (Ultradent) and Herculite XRV Ultra (Kerr) were prepared in Teflon moulds (5mm in diameter and 2mm thick) and cured with polywave Bluephase® G2 (Ivoclar Vivadent), polywave Valo (Ultradent) or monowave Bluephase® (Ivoclar Vivadent; control) resulting in 9 groups. DC and KHN were determined using micro-Raman spectroscopy and Knoop microhardness, respectively. High-performance liquid chromatography and nuclear magnetic resonance spectroscopy were used to confirm the presence or absence of TPO in the three uncured materials. Data were statistically analysed using two-way and one-way ANOVA and DC and KHN were correlated using Pearson's correlation (α=0.05).Results: TPO was confirmed in Tetric EvoCeram and Vit-l-escence but not in Herculite XRV Ultra. All three LCUs produced comparable KHN for Tetric EvoCeram and Herculite XRV Ultra (p>0.05). Both polywave LCUs resulted in significantly higher KHN for Vit-l-escence and higher DC in Tetric EvoCeram and Vit-l-escence than the monowave Bluephase® (p<0.05). Conversely, Bluephase® showed higher DC than the two polywave LCUs in Herculite XRV Ultra (p<0.05). Pearson's correlation coefficient was r=0.818.Conclusions: Polywave LED LCUs improved monomer to polymer conversion and KHN in the two TPO-containing RBCs, but not in Herculite XRV Ultra. DC and KHN were linearly correlated in all three RBCs. Vit-l-escence showed the highest DC and KHN of the three materials tested.Clinical significance: The use of polywave LEDs significantly improves both the DC and KHN of materials which contain TPO. This should be taken into account when curing bleached shades of RBCs even if the manufacturers do not indicate the presence of TPO in their materials.

Silver compounds used in dentistry for caries management: A review - Corrected Proof

J.J.-Y. Peng, M.G. Botelho, J.P. Matinlinna — 2012-04-05

Abstract: Objective: Silver compounds have been used for their medical properties for centuries and in dentistry for more than a century. The aim of this review is to examine the evidence supporting the therapeutic use of silver in dentistry and the outcomes from the clinical trials, as well as mode of action and biocompatibility.Data sources: Literature was searched using the PubMed database between the year 1966 and 2011, with principle key terms such as “Silver Nitrate”, “Silver Fluoride”, “Silver Diammine Fluoride”, “Silver compounds” and “Dental caries”. Hand searching was performed for relevant papers cited in the indices back to the year 1905.Results: In vitro, in vivo and clinical evidence have demonstrated that silver compounds are viable agents for preventing and arresting caries both in the primary and permanent dentition; however they are associated with adverse tooth discolouration and some reports that pulp irritation may occur. Further research has investigated its effectiveness as a dentine desensitiser, root canal disinfectant and even in silver impregnated restorative materials. The mode of action of silver compounds on carious tooth tissues is thought to include inhibition of the demineralization process, as well as an anti-bacterial effect by interference of bacterial cell membranes, cytoplasmic enzymes and inhibition of bacterial DNA replication.Conclusion: Silver compounds have been shown to be an effective anti-caries agent; however, there is an incomplete understanding of how silver compounds prevent caries. Further research is required to help identify its most efficacious use and limitations.

Hydroxyapatite effect on photopolymerization of self-etching adhesives with different aggressiveness - Corrected Proof

Ying Zhang, Yong Wang — 2012-03-23

Abstract: Objective: To understand the correlation of the acidic monomer/hydroxyapatite (HAp) reaction with the photopolymerization behaviour of self-etching adhesives with different aggressiveness.Methods: Two commercial self-etching adhesives the strong Adper Prompt L-Pop (APLP, pH∼0.8) and the mild Adper Easy Bond (AEB, pH∼2.5) were used. HAp powders were incorporated into both adhesives to acquire solutions with concentrations of 0, 1, 3, 5, 7wt%. The attenuated total reflectance Fourier transform infrared (ATR/FT-IR) technique was employed to collect the in situ spectra during light-curing, from which the degree of conversion (DC) and polymerization rate (PR) were calculated. The pH of each tested solution was also measured.Results: Without HAp incorporation, the DC and PR of the strong APLP (7.8% and 0.12%/s, respectively) were much lower than those of the mild AEB (85.5% and 5.7%/s, respectively). The DC and PR of APLP displayed an apparent increasing trend with the HAp content. For example, the DC increased from 7.8% to 58.4% and the PR increased from 0.12 to 3.8%/s when the HAp content increased from 0 to 7wt%. In contrast, the DC and PR of AEB were much less affected by the HAp content. The observations were correlated well with the spectral and pH changes, which indicated that APLP underwent a higher extent of chemical reaction with HAp than AEB.Conclusions: The results disclosed the important role of the acidic monomer/HAp chemical reaction in improving the photopolymerization of the strong (low-pH) self-etching adhesives such as APLP. The phenomenon of polymerization improvement strongly depended on the adhesive aggressiveness.

Adjunctive azithromycin in the treatment of aggressive periodontitis: Microbiological findings of a 12-month randomized clinical trial - Corrected Proof

2012-03-22

Abstract: Objectives: To compare the subgingival microbiological outcomes of azithromycin or placebo as adjuncts to scaling and root planing (SRP) in the treatment of aggressive periodontitis (AgP), and to secondarily evaluate the microbiological effect of supragingival scaling in AgP patients.Methods: Twenty-four AgP subjects 13–26years of age received a 15-day programme of supragingival scaling (SC) and were then randomly assigned to SRP with systemic azithromycin or placebo. Subgingival samples were taken with sterile paper points at baseline, 15days after SC, and at 3, 6 and 12months following SRP. Microbiological analysis was performed by the checkerboard DNA–DNA hybridization.Results: Changes in bacterial levels from baseline to 15days after SC were similar in the 2 groups. When subjects were analysed as a single group, significant reductions after SC were observed for Actinomyces gerencseriae, Capnocytophaga ochracea, and Treponema denticola. During the 12-month follow-up, levels of most of the bacteria decreased in both groups in a similar pattern. For instance, Actinomyces israelli, Veillonella parvula, Streptococcus gordonii, C. ochracea, Eikenella corrodens, Eubacterium nodatum, Fusobacterium periodonticum and Fusobacterium nucleatum ssp. polymorphum decreased significantly within the groups.Conclusions: Azithromycin was ineffective in lowering the subgingival levels of important putative periodontal pathogens in young AgP subjects compared to placebo.Clinical significance: Scaling and root planing with adjunctive systemic azithromycin provides little additional benefit compared to placebo in reductions of major subgingival periodontal pathogens.

Two-year bond strengths of “all-in-one” adhesives to dentine - Corrected Proof

2012-03-19

Abstract: Objectives: To test the long-term in vitro bonding performance of “all-in-one” self-etch adhesives to dentine.Methods: Adper Prompt (3M ESPE), Bond Force (Tokuyama), Brush & Bond (Parkell), iBond Self Etch (Heraeus Kulzer), OptiBond All-In-One (Kerr), and Xeno IV (Dentsply Caulk) were tested. The two-step self-etch adhesive Clearfil SE Bond (Kuraray) served as the control. Extracted human teeth were assigned to groups after creation of smear layer on occlusal dentine. Adhesives were applied according to manufacturers’ instructions, and resin composite (Filtek Z250, 3M ESPE) build-ups were placed. The bonded specimens were sectioned into beams after 24h of storage in water. Microtensile bond strengths (μTBS) was determined at baseline, and following one and two years of water storage using an EZ-Test device (Shimadzu). Representative specimens were examined under field emission scanning electron microscope. Fracture mode was recorded. The data were analyzed using linear mixed effects and least square means analyses. The significance level was set at 0.01 for the pairwise comparisons and at 0.05 for the overall model effects.Results: The mean μTBS decreased significantly over time for Adper Prompt, iBond Self Etch, and OptiBond All-In-One. After two years of water ageing, Bond Force, Brush & Bond, OptiBond All-In-One, and Xeno IV had mean μTBS values not statistically different from Clearfil SE Bond.Conclusions: After two years of water ageing, Clearfil SE Bond outperformed two of six all-in-one adhesives. That indicates that the composition of the adhesives rather than their application approach is accountable for their performance.Clinical significance: Despite the data available suggesting that most all-in-one adhesives are severely affected by hydrolytic degradation, results of the present in vitro study suggest that some may perform as well as the clinically proven Clearfil SE Bond in the longer term.

Effects of two in-office bleaching agents with different pH values on enamel surface structure and colour: An in situ vs. in vitro study - Corrected Proof

Yue Sa, Dongping Chen, Yi Liu, Weiye Wen, Meng Xu, Tao Jiang, Yining Wang — 2012-02-29

Abstract: Objectives: To investigate in situ and in vitro effects of acidic and neutral in-office bleaching agents on human enamel in terms of chemical structure and tooth colour.Methods: Ninety enamel slabs were obtained from premolars. Then specimens were randomly distributed into six groups (n=15) and the human saliva (HS) in volunteers’ oral cavities was used to simulate in situ condition: group Beyond+distilled water (DW); group Opalescence Boost (O-Boost)+DW; group control+DW; group Beyond+HS; group O-Boost+HS and group control+HS. Twice in-office bleaching treatments were performed with a one-week interval and the total bleaching time was 90min. ATR-IR spectroscopy, Raman spectroscopy and colour measurement were performed before the bleaching treatment and after one week post-treatment, respectively. Then ATR-IR and Raman spectroscopies were analysed and the carbonate: mineral (C:M) ratio, Raman absolute intensity (RAI), Raman relative intensity (RRI) and laser-induced fluorescence intensity (FI) were calculated for evaluation.Results: C:M ratio and percentage RRI showed significantly decrease in group Beyond+DW (p<0.001, p<0.001) while little variation was observed in the other groups (p>0.05, p>0.05). Percentage FI and ΔE revealed statistical difference in all bleached groups (p<0.001, p<0.001) while no statistical difference in control groups (p>0.05, p>0.05).Conclusion: Acidic and neutral in-office bleaching agents had the same whitening efficiency in situ and in vitro. Acidic agents could induce demineralisation of human enamel in vitro and the presence of natural human saliva could minimise this adverse effect.

Patients’ perspective on dental aesthetics in a South-eastern European community - Corrected Proof

2012-02-06

Abstract: Objectives: To assess the importance attributed to dental aesthetics by subjects from a Romanian community. In addition, the role played by dental colour, the group-distributions based on the self-evaluation of dental colour and the previous experience regarding whitening treatments are analysed.Methods: A multiple-choice questionnaire was administered to 540 patients in dental offices in Cluj-Napoca, Romania; the subjects were also asked to self-evaluate their dental shade, using a set of images as a comparison. Answers to the questionnaires were statistically analysed using Microsoft Excel and SPSS 13.00 (Pearson's chi-square test, Fisher's exact test, Kendall's tau b).Results: From the participants, 17.96% were motivated by aesthetic reasons to ask for treatment; most of the patients evaluated their smile as “acceptable” (38.51%) or “having some defects” (29.44%) and were self-included in groups of medium and dark shades (33.7% and 33.89%, respectively). Whilst 22.40% of the subjects considered the dental colour as being the most evident defect of their dentition, 39.07% indicated a self-perception of “an abnormal dental shade”. A strong correlation between darker self-assessed tooth colour-groups and the self-perception of an abnormal tooth colour was found (Chi square p≪0.001, Kendall's tau-c=0.44, with p≪0.001). Previous whitening treatments were reported by 8.88% of the subjects.Conclusions: Among patients who wanted to improve one of their oral functions, the majority requested changes in aesthetics. Dental shade is one of the aspects recognized as problematic by the participants, but nonetheless the percentage of patients who had previously benefited by whitening treatments was moderate.

Opalescence of bleached teeth - Corrected Proof

Max Schmeling, Hamilton Pires Maia, Luiz Narciso Baratieri — 2012-02-03

Abstract: Objectives: To evaluate the influence of tooth bleaching on the opalescence properties of enamel.Methods: Colour of 38 specimens was determined by colorimetric analysis before and after bleaching in the reflectance and transmittance modes. The results were described as CIELab colour coordinates. The Opalescent Parameter (OP) was calculated as the difference in yellow–blue colour coordinate (CIE Δb*) and red–green colour coordinate (CIE Δa*) between the reflected and transmitted colours.Results: Mean OP value of the specimens was 18.9 (±1.6) before bleaching and 16.1 (±1.0) after bleaching.Conclusions: Bleaching decreases the OP of the specimens (p>0.001). OP decrease was correlated with differences in b* colour coordinate in the transmittance mode.

Evaluation of self shade matching ability of dental students using visual and instrumental means - Corrected Proof

Samar AlSaleh, Manal Labban, Morouj AlHariri, Esam Tashkandi — 2012-01-27

Abstract: Objectives: The purpose of this study was to evaluate the ability of dental students to match the shade of their own teeth.Methods: Fifty female dental students in the College of Dentistry at King Saud University, who had not received any formal dental training in colour science or shade matching procedures, were screened for colour deficiencies and selected to participate in the study. Each subject and three clinicians selected independently the closest match for the subjects’ own right or left sound maxillary central incisors under controlled viewing conditions, using VITA classical shade guide (VITA Zahnfabrik GmbH, Bad Säckingen, Germany). Each examined central incisor and the 16 samples of VITA classical shade guide were measured with the VITA Easy Shade (VES) spectrophotometer to determine the CIELAB colour parameters. The colour differences (ΔE) between each examined tooth and the 16 samples of the shade guide were calculated. The minimum ΔE values were compared to ΔE values of the shade obtained by VES, subjects and clinicians.Results: The results showed a significant difference in the accuracy of shade selection between the instrumental and visual means. ΔE value of shade selected by clinicians was significantly lower than those selected by the subjects.Conclusions: It was concluded that, spectrophotometric shade analysis was more accurate compared to human shade assessment.Clinical significance: A reliable self-perception of the subjects’ own tooth colour, may aid in the shade matching procedures. It might lead to increased patients’ satisfaction at the finalization of the restorative procedures.

Intrinsic and extrinsic discolouration of dimethacrylate and silorane based composites - Corrected Proof

Çağatay Barutcigil, Mehmet Yıldız — 2012-01-06

Abstract: Objective: The purpose of this study was to evaluate the intrinsic and extrinsic colour change of dimethacrylate and silorane-based composites.Materials and methods: Five contemporary composites were included within the study (Filtek LS Low Shrink Posterior Restorative [SIL], Filtek SupremeXT [SPR], Filtek Z250 [Z25], Filtek P60 [P60], and Admira [ADM]). Twenty-five specimens (8-mm diameter, 1.5-mm thickness) were prepared for each composite. After baseline colour measurements were taken, specimens were immersed in 4 staining solutions (red wine, coffee, cola, and tea) or distilled water (n=5). After a 24-h and 1-month immersion, the colour values of each specimen were remeasured and the colour change values () were calculated. Statistical analyses were evaluated by one-way ANOVA and Tukey HSD test.Results: Amongst the solutions, red wine had the highest value in all the composite restoratives. After the final measurement, ADM exhibited the lowest discolouration, whereas SPR exhibited the highest colour change. Additionally, the colour change for SIL after 1 month in distilled water was higher than the clinically accepted cut-off of 3.3. This change was correlated with an increasing L value according to the multiple regression analysis.Conclusion: All of the restorative materials used in this study were susceptible to staining by commonly consumed beverages drinks, especially red wine and coffee; however, in water, only SIL became whiter with time.

Clinical fitting of CAD/CAM zirconia single crowns generated from digital intraoral impressions based on active wavefront sampling - Uncorrected Proof

Roberto Scotti, Paolo Cardelli, Paolo Baldissara, Carlo Monaco — 2011-10-17

Abstract: Objectives: The aim of this clinical trial was to test the accuracy of single all-ceramic zirconia crowns resulting from digital intraoral impressions with active wavefront sampling technology by measuring the marginal and internal fits of the crowns.Materials and methods: Thirty-seven teeth (24 anterior and 13 posterior) in fifteen patients were restored with single zirconia-ceramic crowns (Lava/Lava Ceram; 3M ESPE) generated from a digital intraoral scanner (Lava Chairside Oral Scanner; 3M ESPE). Before definitive insertion, silicone replicas were produced for all 37 crowns. The sample was cut in four sections; each section was evaluated in four points: marginal gap, mid-axial wall, axio-occlusal edge and centro-occlusal. A total of 592 measurements (148 for each evaluation point) was examined using stereomicroscopy with a magnification of 50×. The Mann–Whitney U test was used to evaluate whether there were differences between anterior and posterior values (alpha=0.05).Results: The mean values for each point were: 48.65μm (SD 29.45μm) for the marginal gap, 112.25μm (SD 55.54μm) at the mid-axial wall, 137.81μm (SD 71.31μm) at the axio-occlusal edge of the abutments, and 157.25μm (SD 75.51μm) at the centro-occlusal location. No statistical differences were found between the anterior and posterior group for each point (p-values: P1=0.39; P2=0.38; P3=0.07; P4=0.30).Conclusions: The marginal and internal fitting values obtained were within literature agreed as clinically acceptable for both anterior and posterior teeth.Clinical relevance: Single crown restorations obtained using digital intraoral impressions based on active wavefront sampling technology presented enough accuracy to be used as an alternative to the conventional impression techniques.