OBJECTIVES: This study examined the effects of additional acid etching on the dentin bond strength of one-step self-etch adhesives with different compositions and pH. The effect of ethanol wetting on etched dentin bond strength of self-etch adhesives was also evaluated. MATERIALS AND METHODS: Forty-two human permanent molars were classified into 21 groups according to the adhesive types (Clearfil SE Bond [SE, control]; G-aenial Bond [GB]; Xeno V [XV]; Beauti Bond [BB]; Adper Easy Bond [AE]; Single Bond Universal [SU]; All Bond Universal [AU]), and the dentin conditioning methods. Composite resins were placed on the dentin surfaces, and the teeth were sectioned. The microtensile bond strength was measured, and the failure mode of the fractured specimens was examined. The data were analyzed statistically using two-way ANOVA and Duncan's post hoc test. RESULTS: In GB, XV and SE (pH < or = 2), the bond strength was decreased significantly when the dentin was etched (p < 0.05). In BB, AE and SU (pH 2.4 - 2.7), additional etching did not affect the bond strength (p > 0.05). In AU (pH = 3.2), additional etching increased the bond strength significantly (p < 0.05). When adhesives were applied to the acid etched dentin with ethanol-wet bonding, the bond strength was significantly higher than that of the no ethanol-wet bonding groups, and the incidence of cohesive failure was increased. CONCLUSIONS: The effect of additional acid etching on the dentin bond strength was influenced by the pH of one-step self-etch adhesives. Ethanol wetting on etched dentin could create a stronger bonding performance of one-step self-etch adhesives for acid etched dentin.
Adhesives* ; Composite Resins ; Dentin* ; Ethanol ; Humans ; Hydrogen-Ion Concentration ; Incidence ; Molar ; Tooth

OBJECTIVES: This study evaluated the effects of the resin thickness on the microhardness and optical properties of bulk-fill resin composites. METHODS: Four bulk-fill (Venus Bulk Fill, Heraeus Kulzer; SDR, Dentsply Caulk; Tetric N-Ceram Bulk Fill, Ivoclar vivadent; SonicFill, Kerr) and two regular resin composites (Charisma flow, Heraeus Kulzer; Tetric N-Ceram, Ivoclar vivadent) were used. Sixty acrylic cylindrical molds were prepared for each thickness (2, 3 and 4 mm). The molds were divided into six groups for resin composites. The microhardness was measured on the top and bottom surfaces, and the colors were measured using Commission Internationale d'Eclairage (CIE) L*a*b* system. Color differences according to the thickness and translucency parameters and the correlations between the microhardness and translucency parameter were analyzed. The microhardness and color differences were analyzed by ANOVA and Scheffe's post hoc test, and a student t-test, respectively. The level of significance was set to alpha = 0.05. RESULTS: The microhardness decreased with increasing resin thickness. The bulk-fill resin composites showed a bottom/top hardness ratio of almost 80% or more in 4 mm thick specimens. The highest translucency parameter was observed in Venus Bulk Fill. All resin composites used in this study except for Venus Bulk Fill showed linear correlations between the microhardness and translucency parameter according to the thickness. CONCLUSIONS: Within the limitations of this study, the bulk-fill resin composites used in this study can be placed and cured properly in the 4 mm bulk.
Fungi ; Hardness ; Humans ; Venus

OBJECTIVES: This study evaluated the effects of the resin thickness on the microhardness and optical properties of bulk-fill resin composites. METHODS: Four bulk-fill (Venus Bulk Fill, Heraeus Kulzer; SDR, Dentsply Caulk; Tetric N-Ceram Bulk Fill, Ivoclar vivadent; SonicFill, Kerr) and two regular resin composites (Charisma flow, Heraeus Kulzer; Tetric N-Ceram, Ivoclar vivadent) were used. Sixty acrylic cylindrical molds were prepared for each thickness (2, 3 and 4 mm). The molds were divided into six groups for resin composites. The microhardness was measured on the top and bottom surfaces, and the colors were measured using Commission Internationale d'Eclairage (CIE) L*a*b* system. Color differences according to the thickness and translucency parameters and the correlations between the microhardness and translucency parameter were analyzed. The microhardness and color differences were analyzed by ANOVA and Scheffe's post hoc test, and a student t-test, respectively. The level of significance was set to alpha = 0.05. RESULTS: The microhardness decreased with increasing resin thickness. The bulk-fill resin composites showed a bottom/top hardness ratio of almost 80% or more in 4 mm thick specimens. The highest translucency parameter was observed in Venus Bulk Fill. All resin composites used in this study except for Venus Bulk Fill showed linear correlations between the microhardness and translucency parameter according to the thickness. CONCLUSIONS: Within the limitations of this study, the bulk-fill resin composites used in this study can be placed and cured properly in the 4 mm bulk.
Fungi ; Hardness ; Humans ; Venus

OBJECTIVES: This study examined the influence of the resin thickness on the polymerization of silorane- and methacrylate-based composites. MATERIALS AND METHODS: One silorane-based (Filtek P90, 3M ESPE) and two methacrylate-based (Filtek Z250 and Z350, 3M ESPE) composite resins were used. The number of photons were detected using a photodiode detector at the different thicknesses (thickness, 1, 2 and 3 mm) specimens. The microhardness of the top and bottom surfaces was measured (n = 15) using a Vickers hardness with 200 gf load and 15 sec dwell time conditions. The degree of conversion (DC) of the specimens was determined using Fourier transform infrared spectroscopy (FTIR). Scratched powder of each top and bottom surface of the specimen dissolved in ethanol for transmission FTIR spectroscopy. The refractive index was measured using a Abbe-type refractometer. To measure the polymerization shrinkage, a linometer was used. The results were analyzed using two-way ANOVA and Tukey's test at p < 0.05 level. RESULTS: The silorane-based resin composite showed the lowest filler content and light attenuation among the specimens. P90 showed the highest values in the DC and the lowest microhardness at all depth. In the polymerization shrinkage, P90 showed a significantly lower shrinkage than the rest two resin products (p < 0.05). P90 showed a significantly lower refractive index than the remaining two resin products (p < 0.05). CONCLUSIONS: DC, microhardness, polymerization rate and refractive index linearly decreased as specimen thickness linearly increased. P90 showed much less polymerization shrinkage compared to other specimens. P90, even though achieved the highest DC, showed the lowest microhardness and refractive index.
Composite Resins ; Ethanol ; Hardness ; Photons ; Polymerization* ; Polymers* ; Refractometry ; Spectroscopy, Fourier Transform Infrared ; Spectrum Analysis

PURPOSE: The aim of this study was to evaluate the effects of additional acid etching and curing mechanism (light-curing or self-curing) of a composite resin on the dentin bond strength and compatibility of one-step self-etching adhesives. MATERIALS AND METHODS: Sixteen human permanent molars were randomly divided into eight groups according to the adhesives used (All-Bond Universal: ABU, Clearfil S3 Bond: CS3), additional acid etching (additional acid etching performed: EO, no additional acid etching performed: EX), and composite resins (Filtek Z-250: Z250, Clearfil FII New Bond: CFNB). Group 1: ABU-EO-Z250, Group 2: ABU-EO-CFNB, Group 3: ABU-EX-Z250, Group 4: ABU-EX-CFNB, Group 5: CS3-EO-Z250, Group 6: CS3-EO-CFNB, Group 7: CS3-EX-Z250, Group 8: CS3-EX-CFNB. After bonding procedures, composite resins were built up on dentin surfaces. After 24-hour water storage, the teeth were sectioned to make 10 specimens for each group. The microtensile bond strength test was performed using a microtensile testing machine. The failure mode of the fractured specimens was examined by means of an optical microscope at x20 magnification. The data was analyzed using a one-way ANOVA and Scheffe's post-hoc test (alpha=.05). RESULTS: Additional etching groups showed significantly higher values than the no additional etching group when using All-Bond Universal. The light-cured composite resin groups showed significantly higher values than the self-cured composite resin groups in the Clearfil S3 Bond. CONCLUSION: The additional acid etching is beneficial for the dentin bond strength when using low acidic one-step self-etch adhesives, and low acidic one-step self-etch adhesives are compatible with self-cured composite resin. The acidity of the one-step self-etch adhesives is an influencing factor in terms of the dentin bonding strength and incompatibility with a self-cured composite resin.
Adhesives ; Collodion ; Composite Resins ; Dental Cements ; Dentin* ; Dentin-Bonding Agents ; Humans ; Molar ; Resin Cements ; Tooth ; Water

OBJECTIVES: This study compared the cyclic fatigue resistance of nickel-titanium (NiTi) files obtained in a conventional test using a simulated canal with a newly developed method that allows the application of constant fatigue load conditions. MATERIALS AND METHODS: ProFile and K3 files of #25/.06, #30/.06, and #40/.04 were selected. Two types of testing devices were built to test their fatigue performance. The first (conventional) device prescribed curvature inside a simulated canal (C-test), the second new device exerted a constant load (L-test) whilst allowing any resulting curvature. Ten new instruments of each size and brand were tested with each device. The files were rotated until fracture and the number of cycles to failure (NCF) was determined. The NCF were subjected to one-way ANOVA and Duncan's post-hoc test for each method. Spearman's rank correlation coefficient was computed to examine any association between methods. RESULTS: Spearman's rank correlation coefficient (rho = -0.905) showed a significant negative correlation between methods. Groups with significant difference after the L-test divided into 4 clusters, whilst the C-test gave just 2 clusters. From the L-test, considering the negative correlation of NCF, K3 gave a significantly lower fatigue resistance than ProFile as in the C-test. K3 #30/.06 showed a lower fatigue resistance than K3 #25/.06, which was not found by the C-test. Variation in fatigue test methodology resulted in different cyclic fatigue resistance rankings for various NiTi files. CONCLUSIONS: The new methodology standardized the load during fatigue testing, allowing determination fatigue behavior under constant load conditions.
Androsterone ; Fatigue

OBJECTIVES: The purpose of this study was to evaluate the effect of various application methods of one-step self-etch adhesives to microtensile resin-dentin bond strength. MATERIALS AND METHODS: Thirty-six extracted human molars were used. The teeth were assigned randomly to twelve groups (n = 15), according to the three different adhesive systems (Clearfil Tri-S Bond, Adper Prompt L-Pop, G-Bond) and application methods. The adhesive systems were applied on the dentin as follows: 1) The single coating, 2) The double coating, 3) Manual agitation, 4) Ultrasonic agitation. Following the adhesive application, light-cure composite resin was constructed. The restored teeth were stored in distilled water at room temperature for 24 hours, and prepared 15 specimens per groups. Then microtensile bond strength was measured and the failure mode was examined. RESULTS: Manual agitation and ultrasonic agitation of adhesive significantly increased the microtensile bond strength than single coating and double coating did. Double coating of adhesive significantly increased the microtensile bond strength than single coating did and there was no significant difference between the manual agitation and ultrasonic agitation group. There was significant difference in microtensile bonding strength among all adhesives and Clearfil Tri-S Bond showed the highest bond strength. CONCLUSIONS: In one-step self-etching adhesives, there was significant difference according to application methods and type of adhesives. No matter of the material, the manual or ultrasonic agitation of the adhesive showed significantly higher microtensile bond strength.
Adhesives ; Dentin ; Dihydroergotamine ; Humans ; Molar ; Resin Cements ; Tooth ; Ultrasonics ; Water

This case report compared the effectiveness of resin infiltration technique (Icon, DMG) with microabrasion (Opalustre, Ultradent Products, Inc.) in management of white spot lesions. It demonstrates that although neither microabrasion nor resin infiltration technique can remove white spot lesions completely, resin infiltration technique seems to be more effective than microabrasion. Therefore resin infiltration technique can be chosen preferentially for management of white spot lesions and caution should be taken for case selection.
Dental Caries ; European Continental Ancestry Group ; Humans

OBJECTIVES: To determine the effect of the spectral output of single and dual-peak light emitting diode (LED) curing lights on the microhardness and color stability of commercial resin composites formulated with camphorquinone and alternative photoinitiators in combination. MATERIALS AND METHODS: Three light-polymerized resin composites (Z100 (3M ESPE), Tetric Ceram (Ivoclar Vivadent) and Aelite LS Posterior (Bisco)) with different photoinitiator systems were used. The resin composites were packed into a Teflon mold (8 mm diameter and 2 mm thickness) on a cover glass. After packing the composites, they were light cured with single-peak and dual-peak LEDs. The Knoop microhardness (KHN) and color difference (DeltaE) for 30 days were measured. The data was analyzed statistically using a student's t-test (p < 0.05). RESULTS: All resin composites showed improved microhardness when a third-generation dual-peak LED light was used. The color stability was also higher for all resin composites with dual-peak LEDs. However, there was a significant difference only for Aelite LS Posterior. CONCLUSIONS: The dual-peak LEDs have a beneficial effect on the microhardness and color stability of resin composites formulated with a combination of camphorquinone and alternative photoinitiators.
Camphor ; Composite Resins ; Enzyme Multiplied Immunoassay Technique ; Fungi ; Glass ; Light ; Polytetrafluoroethylene

The purpose of this study was to evaluate the effect of Er,Cr:YSGG laser irradiation with hypersensitivity mode on microtensile bond strength of composite resin. Twenty extracted permanent molars were randomly assigned to six groups, according to the irradiation of Er,Cr:YSGG laser, adhesive system (Optibond FL or Clearfil SE bond) and application time of etchant (15 sec or 20 sec). Then composite resin was build up on each conditioned surface. The restored teeth were stored in distilled water at room temperature for 24 h and twelve specimens for each group were prepared. All specimens were subjected to microtensile bond strength and the fracture modes were evaluated. Also, the prepared dentin surface and laser irradiated dentin surface were examined under SEM. The results were as follows: 1. The microtensile bond strength of laser irradiated group was lower than that of no laser irradiated group. 2. Regardless of laser irradiation, the microtensile bond strength of Optibond FL was higher than that of Clearfil SE bond. And the microtensile bond strength of 20 sec etching group was higher than that of 15 sec etching group when using Optibond FL. 3. The SEM image of laser irradiated dentin surface showed prominent peritubular dentin, opened dentinal tubules and no smear layer.
Adhesives ; Dentin ; Hypersensitivity ; Molar ; Resin Cements ; Smear Layer ; Tooth ; Water