Mustafa Ulker

Silorane‐Based Composite: Depth of Cure, Surface Hardness, Degree of Conversion, and Cervical Microleakage in Class II Cavities

OBJECTIVE The purpose of this study was to determine the depth of cure, degree of conversion (DC), hardness, and cervical sealing ability of silorane-based composite (Filtek Silorane [FS; 3M, Seefeld, Germany]) and to compare with methacrylate-based composites (MBCs = Filtek Supreme XT [FSXT] and Filtek P60 [FP60]). MATERIALS AND METHODS The DC and hardness of every material were evaluated after 1, 7, and 30 days. The depth of cure was determined using the ISO 4049:2000 standard. Microleakage was evaluated by measuring dye penetration across the gingival wall in cross-sectioned specimens. RESULTS FS showed lower depth of cure than FSXT and FP60. The DC of FS was significantly lower when compared to FP60 and FSXT. FS exhibited lower hardness than both FSXT and FP60 after 1 day of storage. The hardness of FS remained unchanged during the storage period. FS showed reduced microleakage scores compared to FSXT and showed similar microleakage scores compared to FP60. CONCLUSIONS In conclusion, the DC and cure depth of FS are lower than those of MBCs. However, FS revealed stable hardness in water that is comparable to MBCs. The sealing ability of FS is similar or even better than that of MBCs.

Microleakage under metallic and ceramic brackets bonded with orthodontic self-etching primer systems.

OBJECTIVE To compare the in vitro microleakage of orthodontic brackets (metal and ceramic) between enamel-adhesive and adhesive-bracket interfaces at the occlusal and gingival sides produced by self-etching primer system with that of conventional acid etching and bonding. MATERIALS AND METHOD Sixty freshly extracted human mandibular premolar teeth were used in this study. The teeth were separated into four groups of 15 teeth each and received the following treatments: Group 1, 37% phosphoric acid gel + Transbond XT liquid primer + stainless steel bracket; Group 2, Transbond Plus Self-Etching Primer (TSEP) + stainless steel bracket; Group 3, 37% phosphoric acid gel + Transbond XT liquid primer + ceramic bracket; Group 4, TSEP + ceramic bracket. After curing, specimens were further sealed with nail varnish, stained with 0.5% basic fuchsine for 24 hours, sectioned and examined under a stereomicroscope, and scored for microleakage for the enamel-adhesive and bracket-adhesive interfaces from both occlusal and gingival margins. Statistical analyses were performed using Kruskal-Wallis and Mann-Whitney U tests. RESULTS The gingival sides in all groups exhibited higher microleakage scores compared with those observed in occlusal sides for both adhesive interfaces. Enamel-adhesive interfaces exhibited more microleakage than did the adhesive-bracket interfaces. Brackets bonded with self-etching primer system showed significantly higher microleakage at the enamel-adhesive interface of the gingival side. CONCLUSIONS TSEP causes more microleakage between enamel-adhesive interfaces, which may lead to lower bond strength and/or white-spot lesions.

Bond Strength of Amorphous Calcium Phosphate–Containing Orthodontic Composite Used as a Lingual Retainer Adhesive

OBJECTIVE To evaluate the shear bond strength and fracture mode difference between amorphous calcium phosphate (ACP)-containing adhesive and conventional resin-based composite material used as an orthodontic lingual retainer adhesive. MATERIALS AND METHODS Forty crowns of extracted lower human incisors were mounted in acrylic resin, leaving the buccal surface of the crowns parallel to the base of the molds. The teeth were randomly divided into two groups: experimental and control, containing 20 teeth each. Conventional lingual retainer composite (Transbond-LR, 3M-Unitek) and ACP-containing orthodontic adhesive (Aegis-Ortho) were applied to the teeth surface by packing the material into the cylindrical plastic matrices with a 2.34-mm internal diameter and a 3-mm height (Ultradent) to simulate the lingual retainer bonding. For shear bond testing, the specimens were mounted in a universal testing machine, and an apparatus (Ultradent) attached to a compression load cell was applied to each specimen until failure occurred. The shear bond data were analyzed using Students t-test. Fracture modes were analyzed by chi(2) test. RESULTS The statistical test showed that the bond strengths of group 1 (control Transbond-LR, mean: 24.77 +/- 9.25 MPa) and group 2 (ACP-containing adhesive, mean: 8.49 +/- 2.53 MPa) were significantly different from each other. In general, a greater percentage of the fractures were adhesive at the tooth-composite interface (60% in group 1 and 55% in group 2), and no statistically significant difference was found between groups. CONCLUSION The ACP-containing Aegis-Ortho adhesive resulted in a significant decrease in bond strength to the etched enamel surface.

The effect of luting cement thicknesses on the push-out bond strength of the fiber posts

Abstract Objective. The aim of this study was to evaluate the effect of luting cement thicknesses on the push-out bond strength of the fiber posts. Materials and methods. Sixty human maxillary canine teeth were endodontically treated. Post spaces were prepared and root specimens randomly divided into three groups: Group 1: etch-and-rinse (Variolink II/Exite DSC), Group 2: self-etch (Panavia F2.0/ED primer) and Group 3: self-adhesive (Clearfil SA Cement). Then each group was divided into four sub-groups according to the cement thickness, as follows: Sub-group 1: 0.35 mm, Sub-group 2: 0.25 mm, Sub-group 3: 0.15 mm, and Sub-group 4: 0.05 mm. Three slices of 1 mm thickness were obtained from each root specimen (n = 15). Push-out tests were performed and data was analyzed with two-way ANOVA and Tukey tests. Results. The etch-and-rinse system (Variolink II) had a significantly higher bond strength compared with the other systems ( p < 0.05). The thickest cement group (0.35 mm) had a significantly lower bond strength compared with the 0.15 and 0.05 mm groups in the etch-and-rinse and self-adhesive groups (p < 0.05). In the self-etch group, the cement thicknesses did not significantly affect the bond strength (p > 0.05). Conclusions. The etch-and-rinse system offered better bonding to root dentine than the self-adhesive and self-etch systems. The increases in cement thickness significantly reduced the bond strength of fiber posts to root dentine for both the etch-and-rinse and self-adhesive systems.

Different lingual retainer composites and the microleakage between enamel-composite and wire-composite interfaces.

OBJECTIVE To assess microleakage of enamel-composite and wire-composite interfaces when retainer wires were bonded with two orthodontic and a flowable composites. MATERIALS AND METHODS Forty-five freshly extracted human mandibular canine teeth were used in this study. Teeth were separated into three groups of 15 teeth each. Round stainless-steel wire of 0.36-in. diameter in three groups was bonded to enamel by Transbond XT (3M Unitek), Transbond LR (3M Unitek), and Venus Flow (Heraeus Kulzer) composites. Specimens were further sealed with nail varnish, stained with 0.5% basic fuchsine for 24 hours, sectioned and examined under a stereomicroscope, and scored for microleakage for the enamel-composite and wire-composite interfaces from mesial and distal margins. Statistical analysis was performed by Kruskal-Wallis and Mann-Whitney U-tests. RESULTS Little or no microleakage was determined at the mesial and distal sides for three composites in two different interfaces, and these findings were not statistically significant (P > .05). No statistically significant differences were observed among all composite groups for the microleakage with either of the interfaces. Venus Flow in the enamel-composite interface and Transbond LR in the wire-composite interface exhibited no microleakage. CONCLUSION The presence of wire in the mesial portion of the lingual retainer did not increase the microleakage at the enamel-composite and wire-composite interfaces in all groups. The microleakage results in this study support the use of all these composites in routine orthodontic practice.

Conversion degree, microhardness, microleakage and fluoride release of different fissure sealants

The purpose of this study was to determine the degree of conversion (DC), microhardness, microleakage and fluoride release of a nano-filled resin based fissure sealant (Grandio Seal, GS) and compare it with an un-filled resin based fissure sealant (Clinpro, CL) and a glass-ionomer based fissure sealant (Fuji Triage, FT). Disk shaped specimens were prepared from tested fissure sealants to determine the DC, Vicker hardness (VHN) and fluoride release (FR). The DC and VHN of each material was evaluated after 24 h. The cumulative fluoride concentrations were evaluated at 1 h, 6 h, 12 h, 1, 7, 15 and 30 days. For microleakage evaluation, fissure sealants were applied to the etched and dried enamel surfaces of sound third molar teeth according to the manufacturers instructions (n=10). After the thermocycling and mechanical loading procedures, microleakage assessments were carried out. Data were analyzed using one-way ANOVA followed by a post hoc Tukey test, the Kruskal Wallis and Mann-Whitney U test (p<0.05). Results revealed differences regarding DC between all groups: FT (89%) > GS (55.02%) > CL (%51.10) (p<0.05). The VHN values were significantly different among all groups in the following order: GS > FT > CL (p<0.05). FT exhibited significantly higher microleakage scores compared to the CL and GS sealants (p<0.05). The FR of FT was significantly greater than CL and GS (p<0.05). Nano-filled resin based sealant can be used as an alternative to other fissure sealant materials because of its superior hardness results and feasible sealing ability.

Microleakage under ceramic and metallic brackets bonded with resin-modified glass ionomer

OBJECTIVE To test the null hypothesis that there is no significant difference between the microleakage of adhesive interferences at the occlusal and gingival margins of both ceramic and metallic brackets bonded with light-cured resin-modified glass ionomer and a conventional adhesive. MATERIALS AND METHODS Sixty freshly extracted human maxillary premolar teeth were randomly divided into four groups of 15 teeth each. Metal and ceramic brackets were bonded to groups 1 and 2 with resin-modified glass ionomer adhesive (RMGIA). Metal and ceramic brackets were bonded to group 3 and group 4 with a conventional adhesive (CA) system. A dye-penetration method was used for microleakage evaluation. Microleakage from the occlusal and gingival margins was determined by a stereomicroscope for the enamel-adhesive and bracket-adhesive interfaces. Statistical analysis was performed using the Kruskal-Wallis test and the Mann-Whitney U-test with a Bonferroni correction. RESULTS The gingival side of all groups exhibited higher microleakage scores compared with the occlusal side for both adhesive interfaces. All bracket and adhesive combinations displayed statistically significant differences in microleakage between the enamel-adhesive and adhesive-bracket interfaces at the occlusal and gingival sides of the brackets (P < .001). When the adhesive systems were compared, the RMGIA showed more microleakage than the CA between the different interfaces. CONCLUSIONS The hypothesis is rejected. RMGIA results in more microleakage between enamel-adhesive interfaces.

Microleakage under orthodontic brackets using high-intensity curing lights

OBJECTIVE To compare the microleakage of the enamel-adhesive-bracket complex at the occlusal and gingival margins of brackets bonded with high-intensity light curing lights and conventional halogen lights. MATERIALS AND METHODS Forty-five freshly extracted human maxillary premolar teeth were randomly separated into three groups of 15 teeth each. Stainless steel brackets were bonded in all groups according to the manufacturers recommendations. Specimens (15 per group) were cured for 40 seconds with a conventional halogen light, 20 seconds with light-emitting diode (LED), and 6 seconds with plasma arc curing light (PAC). After curing, the specimens were further sealed with nail varnish, stained with 0.5% basic-fuchsine for 24 hours, sectioned and examined under a stereomicroscope, and scored for microleakage for the enamel-adhesive and bracket-adhesive interfaces from both the occlusal and gingival margins. Statistical analyses were performed using Kruskal-Wallis and Mann-Whitney U-tests with a Bonferroni correction. RESULTS The type of light curing unit did not significantly affect the amount of microleakage at the gingival or occlusal margins of investigated interfaces (P >.05). The gingival sides in the LED and PAC groups exhibited higher microleakage scores compared with those observed on occlusal sides for the enamel-adhesive and adhesive-bracket interfaces. The halogen light source showed similar microleakage at the gingival and occlusal sides between both adhesive interfaces. CONCLUSIONS High-intensity curing units did not cause more microleakage than conventional halogen lights. This supports the use of all these curing units in routine orthodontic practice.

Bond strengths of an antibacterial monomer-containing adhesive system applied with and without acid etching for lingual retainer bonding

The aim of this study was to test the null hypothesis that there is no significant difference in bond strength and failure site location of composite bonded to etched and unetched enamel with an antibacterial monomer-containing adhesive and a conventional lingual retainer adhesive system. The crowns of 60 extracted lower human incisors were mounted in acrylic resin leaving the lingual surface of the crowns parallel to the base of the moulds. The teeth were randomly divided into three equal groups: two experimental and a control. Conventional lingual retainer composite (Transbond LR) and antibacterial monomer-containing adhesive (Clearfil Protect Bond), with or without prior etching, were applied to the lingual surface of the teeth by packing the material into cylindrical plastic matrices (Ultradent) with an internal diameter of 2.34 mm and a height of 3 mm to simulate lingual retainer bonding. The shear bond data were analysed using analysis of variance and Tukeys tests. Fracture modes were analysed by chi-square test. Statistical analysis showed that the bond strengths of the control (Transbond LR, mean: 24.77 +/- 9.25 MPa) and Clearfil Protect Bond with etching, (mean: 20.24 +/- 8.5 MPa) were significantly higher than Clearfil Protect Bond without etching, (mean: 12.56 +/- 6.93 MPa). In general, a greater percentage of the fractures were adhesive, at the tooth-composite interface (60-65 per cent). No statistically significant difference was found among the groups. The hypothesis is thus rejected. Within the limits of this in vitro model, antibacterial monomer-containing self-etch adhesive with acid etching did not significantly affect shear bond strength when compared with the control. However, the same adhesive used without acid etching resulted in a significant decrease in bond strength.

The effects of three different desensitizing agents on the shear bond strength of composite resin bonding agents

The aim of this study was to evaluate the effects of three desensitizing agents on the shear bond strengths of four different bonding agents used to bond composite resin to dentin. A total of 160 extracted human molars were sectioned parallel to the occlusal plane under water cooling, polished and randomly divided into 4 groups of 40. Each group was treated with a different desensitizing agent (Tooth Mousse, Ultra-EZ, Cervitec Plus), except for an untreated control group. Each group was then randomly subdivided into 4 groups of 10, and a different dentin bonding agent (XP Bond, AdheSE, Adper Prompt L-pop, GBond) was applied to each group in order to bond the specimens to a resin composite (Gradia Direct) built up using a plastic apparatus. A Universal Testing Machine was used to measure the shear bond strength of each specimen. Statistical analysis was performed using one-way ANOVA and Tukeys tests. With the exception of the Control/AdheSE and Ultra-EZ/XP Bond groups, no statistically significant differences were found in the shear bond strength values of the groups tested. These findings suggest that the use of different desensitizing agents does not affect the shear bond strength of various adhesive systems used to bond resin composite to dentin.