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    Effect of 1% chlorhexidine gel on the bonding strength to dentin
    (Elsevier Taiwan, 2010) Dalli, Mehmet; Ercan, Ertugrul; Zorba, Yahya Orcun; Ince, Bayram; Sahbaz, Cafer; Bahsi, Emrullah; Colak, Hakan
    Background/purpose: The purpose of this in vitro study was to evaluate the effect of 1% chlorhexidine (CHX) gel on dentin bond strengths of posterior composite resin applied with two different adhesive systems. Material and methods: In total, 75 extracted, caries-free human molars were used. The occlusal surface of each tooth was ground to create a flat dentin surface. Then, each tooth was mounted in acrylic. The dentin specimens were randomly assigned to five groups of 15 specimens each. In Group 1, Prime Et Bond NT (PBNT) was applied; in Group 2, a 1% CHX gel + etching for 15 s + PBNT were applied; in Group 3, etching + 1% CHX gel + PBNT were applied; in Group 4, Clearfil S-3 Bond was applied; and in Group 5, 1% CHX gel + Clearfil S-3 Bond were applied. A dentine bonding system was applied to dentin surfaces, and composite cylinders were built up using a special device and then light-polymerized. Specimens were mounted and sheared using an Instron universal testing machine at a cross-head speed of 0.5 mm/min. Results: The results were recorded in megapascals. The sheared specimens were examined under a light microscope, and the type of failure (adhesive, cohesive or mixed) was recorded. Data were compared by one-way analysis of variance and Tukey's honestly significant difference tests. Means were 16.4 +/- 4.1 MPa in Group 1, 16.2 +/- 3.9 MPa in Group 2, 13.0 +/- 4.5 MPa in Group 3, 11.9 +/- 2.7 MPa in Group 4, and 11.5 +/- 2.7 MPa in Group 5. The use of 1% CHX gel before acid etching was significantly higher than after etching on the shear bond strength of PBNT (P < 0.05), but did not differ significantly from PBNT alone (P > 0.05). Conclusion: Within the limitations of the present in vitro study, it was concluded that 1% CHX gel application did not adversely affect the shear bond strengths of dentin-bonding agents.
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    Effect of Different Cavity Disinfectants on Shear Bond Strength of Composite Resin to Dentin
    (Quintessence Publishing Co Inc, 2009) Ercan, Ertugrul; Erdemir, Ali; Zorba, Yahya Orcun; Eldeniz, Ayce Unverdi; Dalli, Mehmat; Ince, Bayram; Kalaycioglu, Baris
    Purpose: The aim of this study was to evaluate the effect of different cavity disinfectants on dentin bond strengths of composite resin applied with two different adhesive systems. Materials and Methods: One hundred mandibular third molars were sectioned parallel to the occlusal surface to expose midcoronal dentin. The dentin surfaces were polished with waterproof-polishing papers The specimens were randomly divided into 5 groups of 20 each. In group 1, the specimens were not treated with any cavity disinfectants and served as control. From groups 2 to 5. dentin surfaces were treated with the following cavity disinfectants, respectively; 2% chlorhexidine solution, 2.5% NaOCl, 1% chlorhexidine gel, 3% H2O2. The specimens were then randomly divided into 2 subgroups including ten teeth each to evaluate the effect of different bonding systems Dentin bonding systems were applied to the dentin surfaces and the composite buildups were created After the specimens were stored in an incubator for 24 h. the shear bond strength was measured at a crosshead speed of 1 mm/min. The bond strength data were analyzed with one way analysis of variance and Tukey-HSD tests. Results: There was no significant difference between chlorhexidine gel and control groups regardless of the type of the bonding agent (p > 0.05). On the other hand, pretreatment with NaOCl, H2O2 or chlorhexidine solutions had a negative effect on the shear bond strength of self-etching bonding systems Conclusion: The findings of this study suggest that when NaOCl, H2O2 or chlorhexidine solution Eire used as a cavity disinfectant, an etch-and-rinse bonding system should be preferred
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    Effect of different light sources in combination with a light-transmitting post on the degree of conversion of resin composite at different depths of simulated root canals
    (Wiley-Blackwell, 2011) Zorba, Yahya Orcun; Erdemir, Ali; Ahmetoglu, Fuat; Yoldas, Oguz
    Aim: ;The aim of this study was to evaluate the degree of conversion (DC) of composite resin at different depths of simulated immature root canals using light-transmitting plastic post (LTPP) and three different light sources. Methodology: ;Composite resin was packed into 60 black plastic cylinders 12 mm in length with 4 mm internal diameters to simulate immature root canals. LTPPs were inserted into half of the simulated canals and the other half acted as controls. Both the simulated canals with LTPPs and the controls were divided into three groups of 10, and each group was cured using either a quartz-tungsten-halogen (QTH), light-emitting diode (LED), or plasma arc (PAC) curing unit. Specimens were sectioned in three horizontally 24 h after curing to represent cervical, middle, and apical levels. DC for each section of composite resin was measured using a Fourier transform infrared spectrophotometer, and data were analyzed using three-way anova and Tukey tests. Results: ;At the cervical level, no significant differences were found between specimens cured using different light sources or between specimens with and without LTPPs (P > 0.05). However, DC was significantly higher in specimens with LTPPs than in those without LTPPs at both the middle and apical levels (P < 0.05). The mean DC of all specimens with LTPPs was significantly higher than that of specimens without LTPPs (P < 0.05). PAC unit showed lower DC than QTH and LED units at both the middle and apical levels; however, the differences were not statistically significant (P > 0.05). Conclusions: ;The results of this study suggest that the use of a LTPP increased the DC of composite resin at the middle and apical levels of simulated immature root canals, but that DC was independent of type of light source.
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    Effects of Different Chlorhexidine Formulations on Shear Bond Strengths of Orthodontic Brackets
    (E H Angle Education Research Foundation, Inc, 2009) Çatalbaş, Bülent; Ercan, Ertuğrul; Erdemir, Ali; Gelgör, İbrahim Erhan; Zorba, Yahya Orcun
    Objective: To test the hypothesis that the application of different chlorhexidine formulations to the etched enamel will not affect shear bond strength (SBS). Materials and Methods: Forty-four freshly extracted human premolars; were collected and stored in distilled water. The teeth were etched with 37% phosphoric and were rinsed and dried. The teeth then were divided into four equal groups. While Group 1 served as a control, Groups 2 to 4 were treated before bonding with a chlorhexidine formulation that included solution (2%), gel (1%), and mouthwash (0.2%). Orthodontic brackets were bonded with Transbond XT (3M Unitek, Monrovia, Calif). Bond strength results were evaluated with the use of one-way analysis of variance (ANOVA) (P < .05) and post hoc tests. Modes of failures were verified by means of scanning electron microscopy. Results: Although no statistically significant difference was observed between Groups 1 and 4 (P > .05), both were statistically superior to Groups 2 and 3 (P < .05). In this in vitro study, the observed measures for Groups 2 and 3 (14.5-10.6 MPa) were lower than those for Groups 1 and 4 (27.3-24.9 MPa), but these values were much higher than those required for clinical use (6-8 MPa). Conclusion: The hypothesis is rejected. The application of chlorhexidine mouth rinse before bonding had no significant effect on the SBS value, and the application of chlorhexidine solution and gel significantly decreased SBS. (Angle Orthod. 2009;79:312-316.)
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    Evaluation of the clinical success of class I cavities prepared by an Er:YAG laser-2-year follow-up study
    (Elsevier Taiwan, 2008) Ercan, Ertugrul; Dulgerfil, Coruh Turksel; Nalcaci, Adil; Dalli, Mehmet; Zorba, Yahya Orcun; Ince, Bayram
    The aim of this study was to evaluate the success of class I occlusal restorations prepared by an Er:YAG laser after 24 months. Sixty-five teeth of 30 patients were included in the study, and an Er:YAG laser emitting at a wavelength of 2.94 mu m was used for the class I cavity preparations with not more than 113 of the mesiodistal width of the occlusal surfaces of each tooth. All cavities were restored with a light-cured composite resin, following a single bond application. After the baseline examination, restorations were reevaluated by the same experienced clinician after 24 months, using modified Ryge criteria. After 2 years, 53 restorations were reviewed in 26 patients. None of the teeth showed signs of secondary caries. Except for 2 teeth subjected to endodontic treatment due to pulpal inflammation, all other restorations were present, and the teeth were vital. Slight marginal discoloration was observed in 5 restorations, having a beta score. With its satisfactory acceptance by patients, class I cavity preparation with an Er:YAG laser would be a useful alternative for other conventional methods, especially for teeth which are to be restored with composite resins. (J Dent Sci, 3(4) : 193-198, 2008)