Influence of Thermal and Mechanical Load Cycling on Fracture Resistance of Premolars Filled with Calcium Silicate Sealer

The aim of this study was to evaluate the aging effect of thermomechanical cyclic load on fracture resistance of lower premolars obturated with AH Plus and BioRoot RCS root canal sealers. Forty-eight single-rooted premolars teeth were instrumented with REVO-S files up to SU/0.06 taper. The teeth were randomly assigned into 2 main groups (n = 24) according to the selected two root canal sealers (AH Plus or BioRoot RCS). All teeth were obturated using matching gutta-percha. Each main group were further divided into 3 subgroups (A, B and C) (n = 8). Group A acted as the negative control group (non-Thermomechanical aging). Whereas Group B and C were subjected first to thermal variations in a thermal cycling machine (7500 and 15,000 thermal cycles), then two different dynamic loading periods namely 3 × 105 and 6 × 105 in a masticatory simulator with a nominal load of 5 kg at 1.2 Hz which simulate approximately 1 ½ and 3 years of clinical function respectively. The roots were decoronated and fracture resistance were measured using a universal testing machine. After thermal-mechanical aging, BioRoot RCS showed significantly higher fracture resistance (p p < 0.05). It could be concluded that thermomechanical aging had a significant impact on the outcome of the fracture resistance of AH Plus and BioRoot RCS

Influence of long -term thermal cycling and masticatory loading simulation on bond strength of roots filled with epoxy resin and calcium silicate based sealers

Abstract Background The aim of this study was to evaluate the effect of thermal and mechanical cyclic aging using a mastication simulator on push-out bond strength of mandibular premolars obturated with AH Plus and BioRoot RCS root canal sealers. Methods With REVO-S files up to SU/0.06 taper, 48 single-rooted premolar teeth were instrumented. The teeth were randomly divided into two main groups (n = 24) based on the two root canal sealers used (AH Plus and BioRoot RCS). All teeth were obturated with h matched-taper single-cone. Each main group was then subdivided into three subgroups (A, B, and C) (n = 8). Group A served as the negative control group (no-thermocycling aging). While groups B and C were subjected to thermal changes in a thermocycler machine (15,000 and 30,000 thermal cycles, respectively), followed by two different dynamic loading periods, 3 × 105 and 6 × 105 in a masticatory simulator with a nominal load of 5 kg at 1.2 Hz which represent roughly 1½ and 3 years of clinical function respectively. 2 mm slice at 3 levels, apical, middle, and coronal, to obtain 3 sections were prepared and subjected to push-out test using a universal testing machine. Statistical analysis was performed using analysis of variance (ANOVA) followed by a Tukey post hoc comparisons test and an independent T-test. A significance level of 5% was used. Results After thermal–mechanical cyclic aging, the two root canal sealers showed a significantly decreased in push-out bond strength (p < 0.05), however, AH Plus had significantly higher bond strength values than BioRoot RCS after cycling aging. Conclusions It could be concluded that thermal–mechanical cyclic aging had a significant impact on the outcome of the dislodgment resistance of AH Plus and BioRoot RCS

Clinical pairing revisited: a study at the University of Malaya, Malaysia

This study is part of ongoing educational research conducted by the Department of Conservative Dentistry, University of Malaya, Malaysia, to evaluate the perception of clinical pairing. A thirteen-question survey was distributed to 148 dental students after they had experienced four-handed dentistry. The objectives were to identify the advantages, disadvantages, and the acceptance of the implementation of clinical pairing from the students' point of view. The responses from the open-ended questions were categorized into six main themes (areas of interest): quality-related (Q), patient-related (PT), partner-related (P), lecturer-related (T), infection control (IC), and learning environment (L). Data analysis was done using SPSS version 18. Results indicated that the students perceived they possessed enough knowledge regarding clinical pairing. However, it was found that they still preferred to work independently as compared to working in pairs. The benefits of clinical pairing may not be viewed in the same vein by both dental students and teachers. The quality-related theme was perceived by students as the main advantage of clinical pairing, whilst the partner-related theme was perceived otherwise. The study also revealed that students may have some preconceived notions about pairing that may have impaired their acceptance. As a consequence, some reluctance was seen in their responses

Clinical pairing revisited: a study at the University of Malaya, Malaysia

This study is part of ongoing educational research conducted by the Department of Conservative Dentistry, University of Malaya, Malaysia, to evaluate the perception of clinical pairing. A thirteen-question survey was distributed to 148 dental students after they had experienced four-handed dentistry. The objectives were to identify the advantages, disadvantages, and the acceptance of the implementation of clinical pairing from the students' point of view. The responses from the open-ended questions were categorized into six main themes (areas of interest): quality-related (Q), patient-related (PT), partner-related (P), lecturer-related (T), infection control (IC), and learning environment (L). Data analysis was done using SPSS version 18. Results indicated that the students perceived they possessed enough knowledge regarding clinical pairing. However, it was found that they still preferred to work independently as compared to working in pairs. The benefits of clinical pairing may not be viewed in the same vein by both dental students and teachers. The quality-related theme was perceived by students as the main advantage of clinical pairing, whilst the partner-related theme was perceived otherwise. The study also revealed that students may have some preconceived notions about pairing that may have impaired their acceptance. As a consequence, some reluctance was seen in their responses

Clinical pairing revisited: a study at the University of Malaya, Malaysia

This study is part of ongoing educational research conducted by the Department of Conservative Dentistry, University of Malaya, Malaysia, to evaluate the perception of clinical pairing. A thirteen-question survey was distributed to 148 dental students after they had experienced four-handed dentistry. The objectives were to identify the advantages, disadvantages, and the acceptance of the implementation of clinical pairing from the students' point of view. The responses from the open-ended questions were categorized into six main themes (areas of interest): quality-related (Q), patient-related (PT), partner-related (P), lecturer-related (T), infection control (IC), and learning environment (L). Data analysis was done using SPSS version 18. Results indicated that the students perceived they possessed enough knowledge regarding clinical pairing. However, it was found that they still preferred to work independently as compared to working in pairs. The benefits of clinical pairing may not be viewed in the same vein by both dental students and teachers. The quality-related theme was perceived by students as the main advantage of clinical pairing, whilst the partner-related theme was perceived otherwise. The study also revealed that students may have some preconceived notions about pairing that may have impaired their acceptance. As a consequence, some reluctance was seen in their responses