The Journal of Adhesive Dentistry, 01/2018

Purpose: This study systematically reviewed the literature to compare the bonding ability of dental adhesives applied to sound dentin (SoD) vs caries-affected dentin (CAD). Materials and Methods: Three international databases (Medline/PubMed, Scopus, and Web of Science) were searched. Eligible studies which evaluated the bond strength to both SoD and CAD were included. Random effects meta-analyses were conducted to calculate pooled mean difference between substrates, separately for etch-and-rinse and self-etch adhesives. Subgroup analyses were carried out to explore heterogeneity considering the methods used for removal of infected carious dentin. A comparison between etch-and-rinse and self-etch adhesives restricted to CAD was also performed. Statistical heterogeneity was considered using the I2 test. The risk of bias of all included studies was assessed. Results: In total, 2260 articles were found, 65 were selected for full-text reading, and 40 studies were included. The meta-analyses favored SoD over CAD for both etch-and-rinse (effect size: -10.04; 95% confidence interval [CI]: -11.94, -8.14; I2 = 95%) and self-etch adhesives (effect size: -6.76; 95% CI: -8.23, -5.30; I2 = 89%). In the subgroup analyses, SoD was favored irrespective of the method used for caries removal (effect size ≤ -4.86; I2 ≥ 28%): excavation (manual or with burs), grinding with abrasive papers, combination of more than one method, and when the method was not mentioned. The meta-analysis restricted to CAD favored etch-and-rinse over self-etch adhesives (effect size: 3.13; 95% CI: 1.82, 4.44; I2 = 72%). Most included studies were judged as having an unclear risk of bias. Conclusion: Bonding to SoD yields better results compared to CAD. Etch-and-rinse adhesives performed better than self-etch adhesives when applied to CAD. Keywords: adhesion, caries detection, dental tissues, etch-and-rinse adhesives, resin-based restoratives, self-etch adhesives

Purpose: The objective of this systematic review was to assess the impact of endodontic post insertion on the clinical performance of endodontically treated teeth (ETT). Materials and Methods: A specific PICO question was developed and a Medline search was performed in January 2017 using relevant terms in order to identify studies comparing the success/survival of dental restorations using endodontic posts or no posts. Additionally, the electronic databases "Opengrey", "BBO", "LILAC" and "IBECS" were assessed and a hand search of cross references from original articles and reviews was performed. The methodological quality of the included studies was assessed independently by three referees using (1) the critical appraisal skills program (CASP) and (2) Cochrane checklist (version 5.1.0). Results: A total of 14 studies were included, among them 11 randomized controlled trials (RCT), two prospective clinical trials, and one retrospective clinical trial. The overall quality of the studies was good according to the CASP. However, the Cochrane rating showed that in seven studies, the risk of bias was high in > 40% of the items, indicating a relevant level of methodological flaws. Three studies showed a low risk of bias in > 80% of the items. The majority (10 out of 14) of the clinical studies included failed to show a positive effect of post placement. A post effect is possible when no cavity wall is present. Conclusion: There is no unequivocal clinical evidence to support or reject the use of posts even for no-wall cavities, either for direct or indirect restorations. Keywords: post, dowel, screw, core, post-retained, no-post, post-free, endocrown, buildup, post-and-core

Purpose: To determine whether the frequency of microleakage at the margin of the tooth-restoration interface in primary molars restored with high-viscosity glass-ionomer cement (HVGIC) differs from that of primary molars restored with amalgam. Materials and Methods: The HVGIC restorations were performed according to the ART method. A total of 19 naturally exfoliated primary molars (10 amalgam and 9 ART/HVGIC) with clinically assessed intact restorations fulfilled the inclusion criteria. SEM analyses using replicas were performed to assess the microgap presence and size of the tooth-restoration interface The depth of a microgap was measured from histological sections after infiltration of 50% (w/v) AgNO3 solution. Independent variables were restorative material, age of restoration, and number of tooth surfaces. Data analyses included Fisher's Exact version of the chi-squared test, independent t-test and one-way ANOVA. Results: More ART/HVGIC than amalgam-restored teeth were gap free (p = 0.14). The mean gap size for teeth with a gap between amalgam (322.0 µm) and ART/HVGIC (201.0 µm) restorations did not differ statistically significantly. AgNO3 infiltration was not influenced by restorative material or age of restoration. Infiltration in multiple-surface was higher than in single-surface restorations (p = 0.02). Conclusion: The occurrence of marginal microleakage in primary molars restored by ART/HVGIC is no different from that observed in primary molars restored with amalgam. Microleakage was deeper in multiple-surface than in single-surface restorations. Despite the presence of microleakage, restoration functionality up to exfoliation is secured, reinforcing the importance of biofilm removal and behavioral education of patients. Keywords: dental caries, primary teeth, amalgam restorations, atraumatic restorative treatment, marginal microleakage, microgap, silver nitrate infiltration, scanning electron microscopy

Purpose: To evaluate the influence of different aging techniques on zirconia-composite microtensile bond strength using different surface treatments over a 5-year follow-up period. Materials and Methods: Zirconia disks received three surface treatments: airborne-particle abrasion with 50-μm aluminum oxide particles, selective infiltration etching (SIE), or fusion sputtering (FS). The specimens were bonded to pre-aged composite disks using a composite cement containing phosphate monomers (Panavia F2.0). Bonded specimens were sectioned into microbars (1 x 1 x 6 mm) using a precision cutting machine, and all microbars received thermocycling (15,000 cycles between 5°C and 55°C). Initial microtensile bond strength was evaluated, and the test was repeated after storage in the following media for five years (artificial saliva, 20% ethanol, 5% NaOH, 4% acetic acid, and 5% phosphoric acid). The test was repeated every 12 months for 5 years. Scanning electron microscopic images were used to analyze the zirconia-composite interface. A repeated measures ANOVA and Bonferroni post-hoc tests were used to analyze the data (n = 20, α = 0.05). Results: Significantly higher microtensile bond strength was observed for SIE compared to fusion sputtering and airborne particle abrasion. Five years of artificial aging resulted in significant reduction of zirconia-composite bond strength for all tested specimens. Zirconia-composite bond strength was more sensitive to storage in sodium hydroxide and phosphoric acid, while it was least affected when stored under saliva. These changes were related to the mechanism of ultra-structural interaction between surface treatment and adhesive, as deterioration of the hybrid layer (composite-infiltrated ceramic) was responsible for bond degeneration. Conclusion: Zirconia-composite bond strength was influenced by 5 years of artificial aging. Keywords: yttria-stabilized zirconia ceramic, microtensile bond strength, surface treatment, resin cements, durability, aging, storage media

Purpose: To determine the irradiance delivered by visible-light curing (VLC) units and obtain information about the exposure times and the maintenance protocols used by dentists. Materials and Methods: The irradiance (mW/cm2) delivered by 526 VLCs from 302 dental offices from the Rhine-Main area, Germany, was measured using an integrating sphere (IS) and a MARC patient simulator (M-PS); additional information was gathered using a survey. Results: Irradiance was measured from 117 standard quartz-tungsten-halogen (QTH), 5 high-power QTH, 2 LED 1st-generation, 333 LED 2nd-generation, 61 LED 3rd-generation, and 8 plasma-arc curing (PAC) units. Depending on the measurement method, 8% (IS) or 11% (M-PS) of the VLCs delivered 400 mW/cm2. Depending on the VLC, the shortest exposure times required to deliver a radiant exposure of 16 J/cm2 ranged from 7 to 294 s. The number of exposure cycles used by dentists when light curing a restoration ranged from 1 to 14. The shortest total exposure time used by dentists on a restoration was 5 s, the maximum was 200 s, and the median was 20 s. Of the 526 VLCs, 41% had intact, undamaged light tips. Only half of the dental offices checked the irradiance from their VLCs regularly, 97% disinfected the VLC, and 86% used eye protection. Conclusion: Approximately 10% of the VLCs delivered 400 mW/cm2 and 14% of the dental offices used no form of eye protection. To achieve sufficient light curing of RBC restorations, more awareness about the VLCs used in the dental office is required. Keywords: visible light curing units, irradiance, exposure time, survey, dental restorations, maintenance

Purpose: To investigate the effect of Ca(OH)2 concentration on pH neutralization, degree of conversion (DC%), and bonding performance of experimental self-etch adhesives (SEAs). Materials and Methods: Four different concentrations of Ca(OH)2 (0 wt%, 1 wt%, 2 wt%, and 4 wt%) were added to the bond of an experimental two-step SEA consisting of primer (10-MDP [30 wt%], TEG-DMA [30 wt%], ethanol [35 wt%], water [5 wt%], camphorquinone [0.5 wt%], and tertiary amine [0.5 wt%]) and bond (bis-GMA [50 wt%], TEG-DMA [30 wt%], HEMA [20 wt%], camphorquinone [0.5 wt%], and tertiary amine [0.5 wt%]) to form four groups: E0, E1, E2 and E4. pH neutralization was evaluated until it reached equilibrium, and DC% within the hybrid layer was analyzed by micro-Raman spectroscopy. Human molars were wet ground until the occlusal dentin was exposed, SEAs were applied, and composite buildups were constructed. After storage in distilled water at 37°C for 24 h, the teeth were cut into composite-dentin beams. Microtensile bond strength (µTBS) was evaluated after 24 h of water storage at 37°C. Nanoleakage was evaluated by SEM. Data were analyzed using ANOVA and Tukey's HSD test (a = 0.05). Results: All the SEAs reached pH equilibrium after thirteen days, with E1 and E4 presenting the highest pH (p 0.05). E0 and E1 presented lower DC% than did E2 and E4 (p 0.05). All the SEAs showed statistically similar mTBS and nanoleakage (p > 0.05). Conclusion: The incorporation of Ca(OH)2 endowed the SEAs with pH-neutralization ability and improved their DC%, without interfering with the bond strength to dentin or nanoleakage extent. Keywords: self-etch adhesives, pH neutralization, calcium hydroxide, degree of conversion, bond strength, nanoleakage

Purpose: To investigate the influence of application time and etching mode of universal adhesives on enamel adhesion. Materials and Methods: Five universal adhesives, Adhese Universal, Bondmer Lightless, Clearfil Universal Bond Quick, G-Premio Bond, and Scotchbond Universal, were used. Bovine incisors were prepared and divided into four groups of ten teeth each. SBS, Ra, and SFE were determined after the following procedures: 1. self-etch mode with immediate air blowing after application (IA); 2. self-etch mode with prolonged application time (PA); 3. etch-and-rinse mode with IA; 4. etch-and-rinse mode with PA. After 24-h water storage, the bonded assemblies were subjected to shear bond strength (SBS) tests. For surface roughness (Ra) and surface free energy (SFE) measurements, the adhesives were simply applied to the enamel and rinsed with acetone and water before the measurements were carried out. Results: Significantly higher SBS and Ra values were obtained with etch-and-rinse mode than with self-etch mode regardless of the application time or type of adhesive. Although most adhesives showed decreased SFE values with increased application time in self-etch mode, SFE values in etch-and-rinse mode were dependent on the adhesive type and application time. Conclusions: Etching mode, application time, and type of adhesive significantly influenced the SBS, Ra, and SFE values. Keywords: universal adhesive, etching mode, application time, enamel bond efficacy