Batu Can Yaman

Microleakage of repaired class V silorane and nano-hybrid composite restorations after preparation with erbium:yttrium–aluminum–garnet laser and diamond bur

The aim of this in vitro study was to compare the microleakage of repaired class V resin composite restorations prepared either by Er:YAG laser or a diamond bur. Ninety-six intact human molar teeth were randomly distributed into eight groups. In the first four groups, class V cavities (3 × 3 × 3 mm) prepared on the buccal and lingual surfaces of the teeth using an erbium:yttrium-aluminum-garnet laser (VersaWave, HOYA ConBio, Japan). Similar class V cavities were prepared in the second four groups using a diamond bur (S-Class, Komet, UK). Teeth in groups 1, 2, and 5, 6 were restored with a nano-ceramic composite (Ceram.X duo, DENTSPLY), whereas a silorane material (Filtek Silorane, 3M ESPE) was used to restore cavities in groups 3, 4, and 7, 8. Two different adhesive systems (XP Bond, DENTSPLY, and Silorane System Adhesive, 3M ESPE) were also used. All specimens were aged for 7 days. New cavities (3 × 3 × 3 mm) were prepared adjacent to the old restorations with Er:YAG laser (groups I–IV) or diamond bur (groups V–VIII). Different repair materials were then applied to the new cavities using the previous two restorative materials and two adhesive systems. All teeth were subjected to thermocycling (5,000 cycles between 5 and 55°C) and axial loadcycling (30 N, 1 Hz, 2,000 cycles). Specimens were immersed in 50% w/w silver nitrate solution. Teeth were sectioned longitudinally in buccolingual direction. Stereomicroscope (Nikon SMZ 800) and SEM (JEOL JSM 5600) were used to evaluate the microleakage that existed at the interface between the old restorations and the repair materials. Data were analyzed statistically with one-way ANOVA and Tukey tests (p < 0.05). Even though no statistically significant differences were found between any of the groups, the cavities repaired with different restoratives showed slight microleakage, especially those prepared by Er:YAG laser (p > 0.05). No microleakage scores were obtained in the groups repaired with Filtek Silorane/Filtek Silorane and Ceram.X/Ceram.X. All the substances tested can be used as repair materials for immediate repair after Er:YAG laser and diamond bur. All substances tested in this study can be used as immediate repair materials after cavity preparations with Er:YAG laser or diamond bur.

Clinical comparison of a flowable composite and fissure sealant: A 24-month split-mouth, randomized, and controlled study

OBJECTIVES The aim of this clinical study was to evaluate the retention rate and caries-prevention effect of a flowable composite compared to a conventional resin-based sealant in a young population over a 24-month period. METHODS Thirty-four patients, ranging in age from 16 to 22 years, diagnosed with at least 2 non-cavitated pit-and-fissure caries in the first and second molars were selected for this randomized split-mouth design trial. A total of 220 sealants, were placed in 117 upper molars and 103 lower molars. The teeth were sealed with a flowable resin composite (Tetric Evo Flow) or a sealant material (Helioseal F). Each restoration was independently evaluated in terms of retention and the presence of caries at baseline and at 1, 6, 12, and 24 months. Data were analyzed using non-parametric Mann-Whitney U and Friedman 1-way ANOVA tests at p<0.05. RESULTS Tetric Evo Flow showed complete retention with 100%, 95.5%, 93.8%, and 88.5% at 1, 6, 12, and 24-month evaluations, respectively, while Helioseal F retention rates were 98.1%, 95.5%, 94.8%, and 85.4%, respectively, for the same evaluation periods. At the 24-month recall, 4 (4.2%) total losses were observed in subjects treated with Tetric Evo Flow and 2 total losses (2.1%) for Helioseal F, respectively. No significant differences were observed between the materials in retention rates or caries incidence for each evaluation period (p>0.05). CONCLUSION Placement of flowable composite as fissure sealants in the younger population seems to be as effective as conventional fluoride containing fissure sealants for the prevention of fissure caries. CLINICAL RELEVANCE The use of a flowable composite as a fissure sealant material, in conjunction with a total-etch, single bottle adhesive, yielded better retention than did the conventional fluoride containing resin-based fissure sealant over a 24-month period in young patients.

Effect of the erbium:yttrium-aluminum-garnet laser or diamond bur cavity preparation on the marginal microleakage of class V cavities restored with different adhesives and composite systems.

The aim of this in vitro study was to compare the microleakage of Er:YAG laser and diamond bur on different bonding systems in class V restorations. Class V cavities were prepared with Er:YAG laser or diamond bur on 80 intact human molars. Teeth were randomly distributed into ten groups and cavities were restored with CeramX duo (DENTSPLY) or Filtek Silorane (3M/ESPE) using different bonding materials (One Coat 7.0 (Coltène), XP Bond (DENTSPLY), Clearfil Protect Bond (Kuraray), AdperSE (3M/ESPE), and Silorane System Adhesive (3M/ESPE). All specimens were subjected to thermocycling and load cycling. After being immersed in silver nitrate dye, the specimens were sectioned. Microleakage was evaluated by stereomicroscope and SEM. Data were statistically analyzed by one-way ANOVA, Kruskal-Wallis, and Mann–Whitney tests. Statistically differences were found between groups (p > 0.05) and cavities prepared with the Er:YAG laser showed higher microleakage than diamond bur. The microleakage of different bonding systems was influenced by the choice of diamond bur or Er:YAG laser for class V composite cavity preparation.

The effects of halogen and light-emitting diode light curing on the depth of cure and surface microhardness of composite resins

Aim: Light-emitting diode light curing units (LED LCUs) have become more popular than halogen LCUs in routine dental restorative treatment. The aim of the study was to compare the effects of two conventional halogen (Hilux Plus and VIP) and two LED (Elipar FreeLight 2 and Smart Lite) light curing units on the depth of cure and the microhardness of various esthetic restorative materials. Materials and Methods: The curing depth and microhardness of a compomer (Dyract Extra), a resin-modified glass ionomer (Vitremer), a packable composite (Sculpt It), an ormocer (Admira), a hybrid composite (Tetric Ceram), two microhybrid composites (Miris and Clearfil Photo Posterior) and, a nanofil composite (Filtek Supreme) were determined using a scraping method and a hardness tester. A total of 320 samples were prepared using the eight different materials (n = 10 samples for each subgroup). The scraping test was based on ISO 4049:2000. Vickers microhardness testing was carried out using hardness tester (Zwick 3212). Data were analyzed using one-way analysis of variance (ANOVA), Bonferroni and the Kolmogorov–Smirnov tests. Results: Best microhardness results were obtained with the LED light curing units and Tetric EvoCeram and Filtek Supreme achieved the highest hardness values. The nanofil composite, Filtek Supreme, showed the best curing depth results in all the tested light curing systems. Conclusions: The LEDs were found to be more successful than the halogen units with respect to both curing depth and microhardness properties.

Effect of thermomechanical aging on bond strength and interface morphology of glass fiber and zirconia posts bonded with a self-etch adhesive and a self-adhesive resin cement to natural teeth

STATEMENT OF PROBLEM Information regarding the effect of thermomechanical aging (TMA) on the bond strength of luting cements to root canal dentin and endodontic posts is limited. PURPOSE The purpose of this study was to investigate the effect of TMA on the bond strength of fiber and zirconia posts bonded to root canal dentin with 2 different resin cements with microtensile and scanning electron microscopic evaluation. MATERIAL AND METHODS Eighty extracted single-rooted human premolars were endodontically treated and restored with either a glass fiber post (FP) or a zirconia post (ZP) with 2 commercially available resin luting cements. The teeth were divided into 2 main groups. In the first group, posts (n=40) were bonded with a self-etch adhesive cement (SEAC). In the second group (n=40), posts were bonded using a self-adhesive cement (SAC). During the first aging phase, all specimens in each group were stored in distilled water for 30 days at 37°C. During the second phase, half of the specimens in each group were subjected to the TMA. The test groups were as follows: FP/SEAC, FP/SEAC+TMA, ZP/SEAC, ZP/SEAC+TMA, FP/SAC, FP/SAC+TMA, ZP/SAC, and ZP/SAC+TMA. The bond strength was measured with a microtensile test. Data were analyzed by 3-way analysis of variance and the Tukey honest significant different test (α=.05). RESULTS FP/SEAC at 30 days was higher than in the other groups. However, bond strength values were significantly reduced in this group after TMA (P<.001). CONCLUSIONS Bond strength values and physical properties of SEAC with higher filler content were more affected by the TMA than those of SALC. According to scanning electron microscopic observation, TMA also affected the micromorphologic interface between the posts and the resin cements as well as between the resin cements and the root canal dentin.

ADHESIVE SYSTEM AFFECTS REPAIR BOND STRENGTH OF RESIN COMPOSITE

Purpose: This study evaluated the effects of different adhesive systems on repair bond strength of aged resin composites. Materials and Methods: Ninety composite discs were built and half of them were subjected to thermal aging. Aged and non-aged specimens were repaired with resin composite using three different adhesive systems; a two-step self-etch adhesive, a two-step total-etch adhesive and a one-step self-etch adhesive; then they were subjected to shear forces. Data were analyzed statistically. Results: Adhesive type and aging significantly affected the repair bond strengths (p<0.0001). No statistical difference was found in aged composite groups repaired with two-step self- etch or two-step total-etch adhesive. One-step self-etch adhesive showed lower bond strength values in aged composite repair (p<0.0001). Conclusion: In the repair of aged resin composite, two-step self-etch and two-step total-etch adhesives exhibited higher shear bond strength values than that of one-step self-etch adhesive.