Effect of different gutta-percha solvents on the microtensile bond strength of various adhesive systems to pulp chamber dentin.

OBJECTIVES: The aim of this study was to evaluate the effect of different endodontic solvents on the microtensile bond strength (µTBS) of various adhesives to pulp chamber dentin. MATERIAL AND METHODS: A total of 120 human third molars were selected. Canals were prepared with the ProTaper Universal system and obturated. The access cavities were then restored with resin composite. After 1 week, a retreatment procedure was applied as follows: control, no solvent was applied to the pulp chamber and experimental groups, three different solvents (chloroform, eucalyptol, and orange oil) were applied to the pulp chamber for 2 min. The canal filling was removed and calcium hydroxide (Ca[OH]2) was placed into the canals. After 7 days, the Ca(OH)2 was removed from the canals and the canals were re-obturated. Teeth were then divided into three subgroups according to the adhesive used. The samples were restored with a nanohybrid resin composite using three different adhesives: Clearfil SE Bond (CSE), Adper Easy One (AEO), and Single Bond 2 (SB2). The samples were aged with thermocycling. Teeth were sectioned, and a total of 20 dentin sticks were obtained for each subgroup. µTBS testing was then performed. The debonded surfaces were evaluated using scanning electron microscopy (SEM) analysis. Data were analyzed using two-way ANOVA and Tukey's post hoc tests. RESULTS: Chloroform showed statistically lower mean µTBS values (14 ± 7.2 MPa) than control group did (19.2 ± 6.1 MPa) (p < 0.05). Orange oil (18.1 ± 6.3 MPa) and eucalyptol (16.9 ± 6.8 MPa) did not reduce the mean µTBS statistically (p > 0.05). Chloroform showed significantly lower bond strength for all adhesives (p < 0.05). Whereas orange oil did not reduce the mean µTBS values of all adhesive systems significantly (p > 0.05), eucalyptol reduced the µTBS values of all the groups, but the results were only statistically significant for SB2 (p < 0.05). CSE showed statistically higher bond strength (20.4 ± 6.8 MPa) than AEO (14.6 ± 5.3 MPa) and SB2 (16.3 ± 7.2 MPa) did (p < 0.05). There were no statistical differences between AEO and SB2 (p > 0.05). According to the SEM analysis of the debonded surfaces, adhesive failures were the most common type in all the groups, followed by mixed failures. CONCLUSIONS: While chloroform reduced the mean bond strength of the adhesive resins, orange oil did not affect the bond strength of the adhesives. The effect of eucalyptol on bond strength depended on the type of adhesive system. CLINICAL RELEVANCE: This study shows that endodontic solvents could affect the microtensile bond strength of adhesives to pulp chamber dentin.

The bond strength of highly filled flowable composites placed in two different configuration factors.

OBJECTIVE: The aim of this study was to evaluate the microtensile bond strength (µTBS) of different flowable composite resins placed in different configuration factors (C-factors) into Class I cavities. MATERIALS AND METHODS: Fifty freshly extracted human molars were divided into 10 groups. Five different composite resins; a universal flowable composite (AeliteFlo, BISCO), two highly filled flowable composites (GrandioSO Flow, VOCO; GrandioSO Heavy Flow, VOCO), a bulk-fill flowable composite (smart dentin replacement [SDR], Dentsply), and a conventional paste-like composite (Filtek Supreme XT, 3M ESPE) were placed into Class I cavities (4 mm deep) with 1 mm or 2 mm layers. Restored teeth were sectioned vertically with a slow-speed diamond saw (Isomet 1000, Buehler) and four micro-specimens (1 mm × 1 mm) were obtained from each tooth (n = 20). Specimens were subjected to µTBS test. Data were recorded and statistically analyzed with two-way analysis of variance and Tukey's post-hoc test. Fractured surfaces were examined using a scanning electron microscope. RESULTS: The µTBS in SDR-1 mm were higher than other groups, where Filtek Supreme XT-2 mm and GrandioSO Flow-2 mm were lower. No significant differences were found between C-factors for any composite resin (P > 0.05). CONCLUSION: Bulk-fill flowable composite provided more satisfactory µTBS than others. Different C-factors did not affect mean µTBS of the materials tested.

Microshear bond strength of preheated silorane- and methacrylate-based composite resins to dentin.

The aim of this study was to investigate the effect of preheating on microshear bond strength (MSBS) of silorane and methacrylate-based composite resins to human dentin. The teeth were randomly divided into three main groups: (1) composite resins were heated upto 68 °C; (2) cooled to 4 °C; and (3) control [room temperature (RT)]. Each group was then randomly subdivided into four subgroups according to adhesive system used [Solobond M (Voco), All Bond SE (Bisco), Clearfil SE Bond (CSE) (Kuraray), Silorane adhesive system (SAS) (3M ESPE)]. Resin composite cylinders were formed (0.9 mm diameter × 0.7 mm length) and MSBS of each specimen was tested. The preheated groups exhibited the highest MSBS (p < 0.001) and the groups cooled to 4 °C exhibited the lowest MSBS (p < 0.001). The CSE showed higher MSBS than the other adhesives (p < 0.001). This study concludes that preheating of composite resins may be an alternative way to increase the MSBS of composites on dentin.

The bond strength of adhesive resins to AH plus contaminated dentin cleaned by various gutta-percha solvents.

The optimal bonding of adhesives to dentin requires the sealer to be completely removed from dentinal walls. The aim of this study was to investigate the effect of different cleaning procedures using gutta-percha solvents on bond strength of adhesive resins to AH Plus contaminated dentin (APCD). The pulp chamber dentin surfaces were contaminated with AH Plus and cleaned with five different techniques (dry cotton, chloroform, orange oil, eucalyptol, and ethanol). Then, Clearfil SE Bond (CSE) (Kuraray), and Tetric N Bond (TNB) (Ivoclar Vivadent) were applied and filled with a composite resin. The serial sticks (1 × 1 mm) were obtained and tested for microtensile bond strength. Scanning electron microscopy (SEM) was used for analysis of debonded surfaces. Ethanol exhibited the highest bond strength to APCD followed by dry cotton. There was no statistically significant difference between ethanol and dry cotton (p > 0.05). Eucalyptol showed the lowest bond strength to APCD and statistically significant differences (p < 0.05) in comparison with other groups. APCD reduced the bond strength of all adhesive resins. Dry cotton, ethanol, and chloroform were the most suitable techniques when used with CSE together, whereas ethanol was best with TNB.

Use of cone-beam computed tomography to evaluate root and canal morphology of mandibular first and second molars in Turkish individuals

Objective: The aim of this study was to investigate the root and canal morphology of mandibular first and second molars in a Turkish population by using cone beam computed tomography (CBCT). Study design: CBCT images of mandibular first (n = 823) and second molar (n = 925) teeth from 605 Turkish patients were analyzed. The root canal configurations were classified according to the method of Vertucci. Results: The majority of mandibular molars (95.8% of first molars, 85.4% of second molars) had two separate roots; however, three roots were identified in 2.06% of first molars and 3.45% of second molars. C-shaped canals occurred 0.85% of first molars and 4.1% of second molars. Three canals were found in 79.9% of first molars and 72.8% of second molars. Most distal roots had a simple type I configuration, whereas mesial roots had more complex canal systems, with more than one canal. The most common root morphology of first and second molars is the two rooted morphology with three canals. Both the mesial and distal roots showed wide variations in canal anatomy with type IV and type I canal configuration predominating in the mesial and distal roots, respectively. Conclusion: Vertucci type I and IV canal configurations were the most prevalent in the distal and mesial roots, respectively, of both the mandibular first and second permanent molar teeth (AU)

Use of cone-beam computed tomography to evaluate root and canal morphology of mandibular first and second molars in Turkish individuals.

OBJECTIVE: The aim of this study was to investigate the root and canal morphology of mandibular first and second molars in a Turkish population by using cone beam computed tomography (CBCT). STUDY DESIGN: CBCT images of mandibular first (n = 823) and second molar (n = 925) teeth from 605 Turkish patients were analyzed. The root canal configurations were classified according to the method of Vertucci. RESULTS: The majority of mandibular molars (95.8% of first molars, 85.4% of second molars) had two separate roots; however, three roots were identified in 2.06% of first molars and 3.45% of second molars. C-shaped canals occurred 0.85% of first molars and 4.1% of second molars. Three canals were found in 79.9% of first molars and 72.8% of second molars. Most distal roots had a simple type I configuration, whereas mesial roots had more complex canal systems, with more than one canal. The most common root morphology of first and second molars is the two rooted morphology with three canals. Both the mesial and distal roots showed wide variations in canal anatomy with type IV and type I canal configuration predominating in the mesial and distal roots, respectively. CONCLUSION: Vertucci type I and IV canal configurations were the most prevalent in the distal and mesial roots, respectively, of both the mandibular first and second permanent molar teeth.

Frequency and distribution of early tooth loss and endodontic treatment needs of permanent first molars in a Turkish pediatric population.

OBJECTIVES: The objective of this study is to evaluate the frequency and distribution of early tooth loss and endodontic treatment needs of permanent first molars in a Turkish pediatric population. MATERIALS AND METHODS: A total of 7,895 panoramic radiographs taken for routine dental examination at the Department of Oral Maxillofacial Radiology between 2008 and 2012 years were investigated. Two independent specialists evaluated early tooth loss and endodontic treatment needs of permanent first molars using panoramic radiography and patient anamnesis forms. The teeth were classified according to the following data: (a) Missing teeth, (b) teeth requiring extraction, (c) endodontically treated teeth (ETT), (d) teeth requiring endodontic therapy. The data also classified according to four factors: Age group (6-12 and 13-16), gender (boy and girl), jaw (mandible and maxilla) and side (right and left). A Chi-square test was used for statistical analyses. RESULTS: A total of 19,488 and 12,092 teeth were evaluated in the child group and adolescent group respectively. All data were higher in adolescents than children (P < 0.001). For gender factor, only ETT was higher in girls than it was in boys (P < 0.001). For the jaw factor, all data were higher (P < 0.001) in mandible than in the maxilla. For the side factor, no statistical difference existed between right and left. CONCLUSIONS: Early tooth loss and endodontic treatment needs of permanent first molars showed variability according to age groups and jaws. When the results were compared according to the side and gender factors, no statistical difference was found (P > 0.05) except with the data of ETT in gender groups.