The Journal of Adhesive Dentistry, 05/2015

Purpose: To meta-analyze the literature on the clinical performance of Class V restorations to assess the factors that influence retention, marginal integrity, and marginal discoloration of cervical lesions restored with composite resins, glass-ionomer-cement-based materials [glass-ionomer cement (GIC) and resin-modified glass ionomers (RMGICs)], and polyacid-modified resin composites (PMRC). Materials and Methods: The English literature was searched (MEDLINE and SCOPUS) for prospective clinical trials on cervical restorations with an observation period of at least 18 months. The studies had to report about retention, marginal discoloration, marginal integrity, and marginal caries and include a description of the operative technique (beveling of enamel, roughening of dentin, type of isolation). Eighty-one studies involving 185 experiments for 47 adhesives matched the inclusion criteria. The statistical analysis was carried out by using the following linear mixed model: log (−log (Y /100)) = β + α log(T ) + error with β = log(λ), where β is a summary measure of the non-linear deterioration occurring in each experiment, including a random study effect. Results: On average, 12.3% of the cervical restorations were lost, 27.9% exhibited marginal discoloration, and 34.6% exhibited deterioration of marginal integrity after 5 years. The calculation of the clinical index was 17.4% of failures after 5 years and 32.3% after 8 years. A higher variability was found for retention loss and marginal discoloration. Hardly any secondary caries lesions were detected, even in the experiments with a follow-up time longer than 8 years. Restorations placed using rubber-dam in teeth whose dentin was roughened showed a statistically significantly higher retention rate than those placed in teeth with unprepared dentin or without rubber-dam (p 0.05). However, enamel beveling had no influence on any of the examined variables. Significant differences were found between pairs of adhesive systems and also between pairs of classes of adhesive systems. One-step self-etching had a significantly worse clinically index than two-step self-etching and three-step etch-and-rinse (p = 0.026 and p = 0.002, respectively). Conclusion: The clinical performance is significantly influenced by the type of adhesive system and/or the adhesive class to which the system belongs. Whether the dentin/enamel is roughened or not and whether rubberdam isolation is used or not also significantly influenced the clinical performance. Composite resin restorations placed with two-step self-etching and three-step etch-and-rinse adhesive systems should be preferred over onestep self-etching adhesive systems, GIC-based materials, and PMRCs. Keywords: cervical restorations, Class V, adhesives, composite restorations, abfraction lesions, clinical trials

Purpose: To evaluate the one-year clinical performance of composite restorations in noncarious cervical lesions placed in smoking and non-smokers using a multimode adhesive system with two adhesive strategies. Materials and Methods: Among the selected cervical lesions, four experimental groups were formed based on the patients' smoking habit and bonding strategies with a multimode adhesive system (n = 38): G1: etchand- rinse in non-smokers; G2: selective enamel etching in non-smokers; G3: etch-and-rinse in smokers; G4: selective enamel etching in smokers. The restorations were paired, ie, each patient received at least two restorations. A nanofilled resin composite was applied and light cured incrementally in all groups by one operator. Two calibrated examiners evaluated the restorations at baseline, 6 and 12 months after placement. The modified USPHS criteria were used for evaluation. Data were analyzed using the chi-square (for associations between groups) and McNemar tests. Results: No statistically significant difference was found between groups for the criteria of retention, marginal discoloration, color match, marginal integrity, or sensitivity after 6 and 12 months. The assessments over time showed a statistically significant difference only for marginal discoloration at 12 months for groups 1, 3, and 4 when compared to baseline (p = 0.031). There were no statistical differences for any criteria evaluated among smokers and non-smokers, except for color match, where a difference was found after the baseline evaluation. Regarding the adhesive strategy, etch-and-rinse resulted in a clinical performance similar to that of selective enamel etching over 12 months. Conclusion: Neither cigarette smoking habit nor adhesive strategy influenced the clinical performance of resin composite cervical restorations over the first year. Keywords: resin composite, clinical trial, dentin bonding system, multimode adhesive system, universal adhesive system, enamel bonding, enamel etching, phosphoric acid, smoking habit, cigarette, tobacco, NCCL

Purpose: The purpose of this study was twofold: 1) to characterize the zirconia (Y-TZP) surfaces through scanning electronic microscopy associated with energy-dispersive spectroscopy and atomic force microscopy after the deposition of a thin organosilicon film by nonthermal plasma (NTP) treatment, and 2) to determine the zirconia surface hydrophilicity, before and after aging, through surface energy analysis. Materials and Methods: Surfaces of 16 zirconia disks (10 x 3 mm) were treated for 30 min each with hexamethyldisiloxane and argon plasmas, followed by oxygen plasma. Disks were analyzed before NTP treatment, immediately after NTP treatment, and after aging for 7, 15, and 30 days. The surface energy of the Y-TZP disks was measured with a goniometer. Quantitative data were submitted to statistical analysis using ANOVA and Tukey's test (p 0.05). Results: Immediately after NTP treatment, the surface energy of the zirconia disks was significantly higher than at any other tested period (p 0.001), and the water contact angle on the zirconia disks was reduced to 0 degrees. Similar surface energy results were obtained before NTP treatment and after 15 or 30 days of aging (p > 0.05; Tukey's test). Energy-dispersive spectroscopy results revealed the presence of carbon, oxygen, and silicon on the surface after NTP treatment. Conclusion: NTP treatment was useful for treating the zirconia surface for cementation procedures, as it produced a high level of hydrophilicity on the zirconia surface. However, this high level of hydrophilicity did not persist after aging. Keywords: Y-TZP, contact angle, nonthermal plasma, surface energy, surface topography, microstructure

Purpose: To evaluate the influence of different surface treatments on roughness and bond strength of composite repairs. Materials and Methods: 120 truncated conical specimens were prepared with composite Grandio SO (VOCO) and submitted to 5000 thermal cycles. Specimens were divided into 12 groups (n = 10) regarding the surface treatments: negative control (NC), without treatment; medium-grit diamond bur (MGD); coarse-grit diamond bur (CGD); conventional carbide bur (ConC); crosscut carbide bur (CutC); chemical vapor deposition diamond bur (CVD); sandblasting with aluminum oxide (AlO); Er:YAG laser 200 mJ/10 Hz (Er200); Er:YAG laser 60 mJ/10 Hz (Er50); Nd:YAG laser 120 mJ/15 Hz (Nd120); Nd:YAG laser 60 mJ/ 15Hz (Nd60); air abrasion with 110-μm silica modified aluminum oxide (Rocatec Plus-3M) (SIL). After the surface treatments, the surface roughness (Ra) was measured using a profilometer, and then the adhesive system Admira Bond (VOCO) was applied. Another truncated conical restoration was built up with the same composite over the bonded area of each specimen. In order to evaluate the cohesive strength, double-cone specimens were made and considered as a control group (CoheC). The specimens were submitted to tensile bond strength testing and the obtained data (MPa) were evaluated by one-way ANOVA, Tukey's and correlation tests. Results: ANOVA showed significant differences among experimental groups for roughness and adhesive strength (p 0.00). The roughness values (Ra) were: NC (0.21 ± 0.19)c; ConC (0.30 ± 0.08)c; CutC (0.50 ± 0.22)cd; CVD (0.74 ± 0.14)bd; MGD (0.89 ± 0.39)ab; Er50 (0.89 ± 0.14)ab; AlO (0.90 ± 0.07)ab; Nd60 (0.94 ± 0.33ab; SIL (0.98 ± 0.07)ab; Nd120 (1.10 ± 0.19)a; CGD (1.10 ± 0.32)a; Er200 (1.12 ± 0.21)a. The results of the tensile bond strength test in MPa were: CGD (11.58 ± 3.03)a; MGD (12.66 ± 3.82)ab; NC (13.51 ± 3.95ab; Nd120 (14.11 ± 5.95)ab; ConC (14.73 ± 6.12)ab; Er200 (15.51 ± 1.45)abc; CVD (15.61 ± 5.00abc; Er50 (16.44 ± 2.75) abc; CutC (16.79 ± 2.98)abc; Nd60 (17.72 ± 2.45)abcd; AlO (18.33 ± 3.19)bcd; SIL (21.13 ± 4.48cd; CoheC (23.50 ± 5.81)d. The groups followed by the same letters were not statistically significantly different (Tukey's test). No correlation was found between bond strength and roughness (r = 0.007). Conclusion: Air abrasion with silica coating (Rocatec) was the only method which resulted in significantly higher bond strength in relation to the negative control group. The increase in laser energy produced a rougher surface, but reduced the bond strength. Keywords: composite resin, composite repair, roughness, bond strength

Purpose: To evaluate the microtensile bond strength (μTBS) of a bulk-fill low-stress resin-based composite to dentin from gingival walls of Class II MOD cavities. Materials and Methods: Class II MOD cavities were prepared in 44 human molars with the distal and mesial proximal boxes 4 and 6 mm deep, respectively. Eight experimental groups (n = 11) were obtained by a factorial design including 1. "composite" in two levels: a bulk-fill low-stress composite (SureFil SDR Flow, Dentsply Caulk) and a conventional composite (Filtek Z350 XT, 3M ESPE); 2. "filling technique" in two levels: bulk-fill (Bf) and incremental (In); and 3. "depth" in two levels: 4 mm and 6 mm in order to create different polymerization conditions. Twenty-four hours after placement of restorations, teeth were sectioned into beams with a cross-sectional bonded area of approximately 1 mm2. Bonded beams obtained from the gingival walls of the proximal boxes were tested in tension at a crosshead speed of 1 mm/min. Data were submitted to a 3-way ANOVA followed by a post-hoc Tukey's test (p 0.05). Results: ANOVA failed to identify significant differences for the triple and double interaction between factors. However, significant differences were observed for the factors "composite" and "filling technique" (p 0.05). SDR presented significantly higher μTBS values for bulk and incremental filling techniques (p 0.05), and the incremental filling technique presented significantly higher μTBS values for both composites (p 0.05). Conclusion: It can be concluded that the bulk-fill flowable composite SDR may improve the bond strength to the gingival walls of Class II MOD cavities. Keywords: tensile strength, bulk-fill composite, filling technique

Purpose: To investigate the clinical behavior of two different resin-based restorative systems in Class II cavities in a controlled prospective split-mouth study over 10 years. Materials and Methods: Thirty patients received 68 resin composite restorations (Solobond M + Grandio: n = 36; Syntac + Tetric Ceram: n = 32) by one dentist in a private practice. 35% of cavities revealed no enamel at the bottom of the proximal box, 48% of cavities provided 0.5 mm of remaining proximal enamel. Restorations were examined according to modified USPHS criteria at baseline, after 6 months, and 1, 2, 4, 6, 8, and 10 years. Results: Twenty-nine out of 30 patients attended the 10-year recall. The overall success rate of all restorations was 96.9%. One Grandio restoration suffered marginal fracture with exposed dentin and one Tetric Ceram restoration failed due to cusp fracture. After 10 years, Grandio showed higher surface roughness (p = 0.03) and less color match (p = 0.024; Mann-Whitney U-test). Molar restorations performed worse than premolar fillings regarding marginal integrity (4 and 10 years), filling integrity (4, 8, and 10 years), and tooth integrity (4, 8, and 10 years). The main reasons for degradation of resin composites were chipping and cracks in molar restorations after 8 years. Beyond the 4-year recall, marginal staining increased (43% bravo for stained margins at four years, 52% at 8 years, and 71% at 10 years). Tooth integrity deteriorated significantly due to more enamel cracks and chipping over time (9% at baseline and 89% after 10 years (p0.05). Conclusions: Direct resin composite restorations performed satisfactorily over 10 years of clinical service. Keywords: resin composites, nanofillers, clinical trial, marginal integrity, etch and rinse