Muhammet Kerim Ayar

Evaluation of resin-enamel interface micromorphology in respect of different Er,Cr:YSGG laser parameters

Abstract Background and objective: Enamel irradiation with an erbium,chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser has been reported to cause micromorphological alterations within resin-enamel interfaces and subsurface enamel. The present study was conducted to evaluate the effects of different output power/pulse repetition rate parameter combinations of Er,Cr:YSGG laser on the micromorphology of resin-enamel interfaces and subsurface enamel. Materials and methods: Thirty-five bovine incisors were used in the present study. Er,Cr:YSGG laser was used on enamel with different output power/pulse repetition rate parameter combinations as follows: 6 W/20 Hz, 6 W/35 Hz, 6 W/50 Hz, 3 W/20 Hz, 3 W/35 Hz, 3 W/50 Hz. Following adhesive and composite procedures, specimens were sectioned and either acid-etched with 37% phosphoric acid for 1 min or immersed in 55% nitric acid for 12 h. Then the resin-enamel interfaces were investigated by scanning electron microscopy (SEM). Results: Micromorphological findings by SEM revealed that when enamel surfaces were irradiated with all 6-W groups and 3 W/20 Hz-combinations, large resin structures indicating subsurface microcracks were generally evident within interfaces and subsurface enamel. However, when irradiated with 3 W/35 Hz and 3 W/50 Hz-combinations, the observed resin-enamel interfaces were similar to those of the acid-etched only group. Conclusion: Deploying Er,Cr:YSGG laser with lower power and high pulse repetition rate combinations may reduce damage to resin-enamel interfaces and subsurface enamel. However, assessment of the relationship between these findings and bond strength requires further study.

The effect of a new calcium‐based agent, Pro‐Argin, on the microhardness of bleached enamel surface

BACKGROUND This study investigated the effects of Pro-Argin application on the microhardness of bleached enamel and compared them with those of acidulated phosphate fluoride (APF) and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) applications. METHODS Forty blocks (4 × 4 × 4 mm) were prepared from the facial surfaces of 10 sound bovine incisors. The enamel surfaces were bleached with 35% hydrogen peroxide three times at 5-day intervals. The specimens were divided into five treatment regimen groups (n = 8 each): Group 1, bleaching/no surface treatment (control); Group 2, bleaching/Pro-Argin toothpaste treatment; Group 3, bleaching/Pro-Argin treatment; Group 4, bleaching/APF treatment; and Group 5, bleaching/CPP-ACP treatment. During bleaching treatments, specimens were stored in artificial saliva. Vickers microhardness measurements were performed at baseline and after treatment in all groups. Statistical analyses were performed using the paired t-test, one-way analysis of variance, and post hoc least significant difference tests. RESULTS After bleaching, hardness values of enamel surfaces increased significantly in the treatment groups versus the control group (p < 0.05). However, no significant difference was found among treatment groups (p > 0.05). CONCLUSIONS Through bleaching treatment, Pro-Argin application may have a positive effect on enamel surface hardness, equivalent to that of CPP-ACP or APF.

Effect of simplified ethanol-wet bonding on dentin bonding durability of etchand-rinse adhesives

This in vitro study evaluated the effects of simplified ethanol-wet bonding technique on dentin bonding durability of two etchand-rinse adhesives to bovine dentin. Sixteen freshly extracted bovine incisors were divided into four groups according to bonding technique (water-wet or ethanol-wet bonding) and adhesive (Single Bond 2 or Prime & Bond NT). After etching and rinsing, dentin surfaces were left either water-moist or immersed in ethanol. Following adhesive application and composite build-up, bonded teeth were sectioned into sticks for microtensile bond strength (µTBS) testing conducted after 24-h and 12-month water storage. There were no significant differences in bond strength among the groups at 24 h. At 12 months, the bond strengths of adhesives to dentin were significantly decreased (p<0.05). Simplified ethanol-wet bonding did not improve the resin-dentin bonding durability of tested etch-and-rinse adhesives.

Effects of Er,Cr:YSGG laser parameters on dentin bond strength and interface morphology.

Previous studies have shown the effects of Er,Cr:YSGG laser irradiation on the dentin bond strength; but there are few reports that show the significance of the irradiation with different laser parameters on dentin bond strength and interface morphology. This in‐vitro study attempted to evaluate the microtensile bond strength (μTBS) and interface morphology of resin‐dentin interfaces, either followed by treatment with Er,Cr:YSGG laser irradiation with different parameters or not. The flattened dentin samples of 35 bovine teeth were embedded into acrylic blocks and randomly divided into seven groups according to surface treatments using Er,Cr:YSGG lasers with different parameters: 3 W/20 Hz, 3 W/35 Hz, 3 W/50 Hz, 1.5 W/20 Hz, 1.5 W/35 Hz, 1.5 W/50 Hz, or no laser treatment (n = 5). Composite buildups were done over bonded surfaces and stored in water (24 hours at 37°C). Specimens were sectioned into sticks that were subjected to μTBS testing and observed under FE‐SEM. Control groups (27.70 ± 7.0) showed statistically higher values than laser‐irradiated groups. There were no significant differences among laser groups. Despite that, increasing the pulse frequency yielded slightly higher bond strength. Depending on laser settings, Er,Cr:YSGG laser irradiation caused interfacial gaps and resin tags with wings morphology. With the parameters used in this study, Er,Cr:YSGG laser irradiation promoted morphological changes within resin‐dentin interfaces and negatively influenced the bond strength of adhesive systems. Microsc. Res. Tech. 78:1104–1111, 2015.

Status of self-etch adhesives for bonding to pulp chamber dentin

Purpose: Present study investigated microtensile bond strengths (μTBS) of four one-step self-etch dental adhesive systems, two two-step self-etch adhesive systems and one three-step etch-and-rinse adhesive system to pulp chamber dentin. Materials and Methods: The μTBS of seven current adhesives, including one three-step etch-and-rinse (Optibond FL, Kerr, USA), two two-step self-etch (Clearfil SE Bond, Kuraray, Japan; AdheSE, Ivoclar, Liechtenstein) and four one-step self-etch adhesives (Clearfil S3 Bond, Kuraray, Japan; Optibond all-in-one, Kerr, USA; iBond, Heraeus Kulzer, Germany; L-POP, 3M ESPE, Germany) were determined. Adhesives were applied to pulp chamber dentin according to their respective manufacturer′s instructions, then μTBS tests were performed. Results: μTBS varied from 29.99 ± 7.82 to 38.15 ± 10.38 MPa. Highest μTBS mean was obtained with Optibond FL and lowest iBond, Heraeus Kulzer, Germany. There were no significant differences among all adhesives. Conclusion: Bonding effectiveness of one-step self-etch adhesive systems to pulp chamber dentin was comparable to two-step self-etch and three-step etch-and-rinse adhesive systems.

Reminder about long-term clinical trials as a gold standard for the bonding effectiveness of adhesive resins

Clinical trials are considered as a gold standard for assessing bonding effectiveness of adhesive materials. However, clinical trials with long evaluation periods (5 years or more) are necessary to discriminate significant differences within the clinical performances of current improved adhesive materials. The present short communication discusses this issue and possible alternatives.

Bond durability of contemporary adhesive systems to pulp chamber dentin

Abstract Objective: The purpose of this study was to evaluate long-term bond strengths of dentin adhesive systems, which include one-step self-etch adhesive systems (Optibond All-in-one, Kerr; Adper Prompt L-POP, 3 M ESPE), a three-step etch-and-rinse adhesive (Optibond FL, Kerr) and two-step self-etch adhesive (AdheSE Bond, Ivoclar), applied to pulp chamber dentin surfaces after 12-month water storage by using microtensile bond strength (µTBS) test. Materials and methods: Dentin adhesive systems were applied to unprepared pulp chamber dentin surfaces according to manufacturer’s directions, respectively (n = 5). After applying adhesive systems, composite buildups were done incrementally. Bond strengths to pulp chamber dentin surfaces were determined using µTBS test after water storage for 24 h and 12 month. Kruskal–Wallis analysis and Mann–Whitney U-test for pairwise comparisons were used to determine statistical differences in µTBS between the groups at a significance level of 5%. Results: There were no significant differences in µTBS between storage periods for tested adhesives regardless adhesive class. Conclusion: Bond durability of tested adhesive systems, including one-bottle self-etch adhesives with pulp chamber dentin surfaces, may be considered stable after 12-month water storage. Therefore, one-step self-etch, also called “user-friendly” adhesives may perform and traditional three-step etch-and-rinse adhesives in the long-term when used for bonding to pulp chamber dentin surfaces.

Repair of aged bulk-fill composite with posterior composite: Effect of different surface treatments

OBJECTIVE In the present study, the ability of posterior resin composite to repair aged bulk-fill resin composite and vice versa were assessed by shear bond strength testing. MATERIALS AND METHODS Resin composite substrates were aged and surfaces were abraded with abrasive papers, then bulk-fill substrates were repaired with posterior resin composite and vice versa using different surface treatments (no surface treatment [control]; etching with 37% phosphoric acid [H3 PO4 ] for 20 seconds; etching with 10% hydrofluoric acid [HF] for 20 seconds; etching with 37% H3 PO4 for 20 seconds + adhesive application; etching with 10% HF for 20 seconds + adhesive application; adhesive application only). Shear bond strengths (SBS) were then measured and surface roughness values (Ra) were determined. Cohesive strengths of nonaged resin composites were measured and used as reference groups. Resin composite surfaces after acid etching were evaluated by SEM. Data were analyzed using ANOVA and Fishers LSD tests (P < .05). RESULTS ANOVA showed that resin composite repair type did not affect SBS significantly (P = .850), while it showed that surface treatments significantly affected the SBS (P = .000). Only a combination of etching with 10% HF for 20 seconds with resin adhesive application provided similar SBS values with those of the positive control. CONCLUSIONS It was concluded that the aged bulk-fill resin composite would be effectively repaired with conventional posterior resin composite or vice versa if proper repair protocol was deployed. CLINICAL SIGNIFICANCE The combination of 10% HF etching and adhesive application would provide efficient repair strength when the aged bulk fill resin composite is repaired with conventional posterior resin composite or vice versa.

Bonding performance of universal adhesives to er,cr:YSGG laser‐irradiated enamel

Universal adhesives have been recently introduced for use as self‐etch or etch‐and‐rinse adhesives depending on the dental substrate and clinical condition. However, their bonding effectiveness to laser‐irradiated enamel is still not well‐known. Thus, the aim of this study was to compare the shear bond strength (SBS) of universal adhesives (Single Bond Universal; Nova Compo‐B Plus) applied to Er,Cr:YSGG laser‐irradiated enamel with SBS of the same adhesives applied in self‐etch and acid‐etching modes, respectively. Crown segments of sixty bovine incisors were embedded into standardized acrylic blocks. Flattened enamel surfaces were prepared. Specimens were divided into six groups according to universal adhesives and application modes randomly (n = 10), as follows: Single Bond Universal/acid‐etching mode; Nova Compo‐B Plus/acid‐etching mode; Single Bond Universal/self‐etching mode; Nova Compo‐B Plus/self‐etching mode; and Single Bond Universal/Er,Cr:YSGG Laser‐etching mode; Nova Compo‐B Plus/Er,Cr:YSGG Laser‐etching mode. After surface treatments, universal adhesives were applied onto surfaces. SBS was determined after storage in water for 24 h using a universal testing machine with a crosshead speed of 0.5 mm min−1. Failure modes were evaluated using a stereomicroscope. Data was analyzed using two‐way of analyses of variances (ANOVA) (p = 0.05). Two‐way ANOVA revealed that adhesive had no effect on SBS (p = 0.88), but application mode significantly influenced SBS (p = 0.00). Acid‐etching significantly increased SBS, whereas there are no significant differences between self‐etch mode and laser‐etching for both adhesives. The bond strength of universal adhesives may depend on application mode. Acid etching may significantly increase bond strength, while laser etching may provide similar bond strength when compared to self‐etch mode.

Nanoleakage within adhesive-dentin interfaces made with simplified ethanol-wet bonding

Abstract Objective: The aim of the present study was to evaluate the effects of the simplified ethanol-wet bonding technique and conventional water-wet bonding technique on short term nanoleakage within hybrid layers made with two different etch-and-rinse adhesives (Single Bond 2 and Prime & Bond NT). Materials and methods: Flat dentin surfaces from bovine incisors were prepared and finished with wet 600-grit abrasive papers, then divided into groups to be bonded with one of the adhesives. After etching and rinsing, dentin surfaces were either moistened with water (water-wet bonding technique) or moistened with absolute ethanol for 1 min (ethanol-wet bonding technique). Then, adhesives were applied, and composite buildups were done. Bonded teeth samples were sectioned into resin–dentin samples by means of a low speed diamond saw under water cooling. Specimens were immersed into a 50% (w/v) solution of silver ammoniacal nitrate for 18 h and exposed to photodeveloping solution for 6 h. The amount of silver nitrate uptake within the adhesive layer, or hybrid layer, was measured with energy dispersive spectroscopy (EDS) in different regions (n = 30). Results: Simplified ethanol-wet bonding significantly reduced nanoleakage within resin–dentin interfaces made with Single Bond 2 and Prime & Bond NT, but improvement at the nanoleakage of Single Bond 2 was only significant. Conclusion: Simplified ethanol-wet bonding may improve quality of hybrid layers made with commercially available simplified etch-and-rinse adhesives. But benefits of ethanol-wet bonding may depend on product.