One-year clinical evaluation of bulk-fill composite resin restorations plasticized by preheating and ultrasonics: A randomized clinical trial.

Introduction: Bulk-fill composite restorations displayed substantial annual failure related to imperfect marginal adaptation. Although preheated composites improved, marginal adaptation demonstrated early loss of plasticity. A new technique of ultrasonics plasticization was used for fabricating restorations. Aim: The aim of this study was to assess the clinical behavior of bulk-fill composite resin restorations plasticized by preheating and ultrasonics. Methodology: Randomized split-mouth double-blinded clinical trial was designed. Bulk-fill composite resin (Tetric N-Ceram Bulk Fill Ivoclar Vivadent products, Delhi) was used to fill 56 cavities. In 28 restorations, composite resin was plasticized by preheating in composite warmer (Delta Co., India) and remaining were plasticized with modified ultrasonic-retreatment tip-RT No 2 (Cricdental, India). Clinical follow-up assessments were done at 6 and 12 months using Ryge's criteria. Mann-Whitney U-test was used for statistical analysis with P < 0.05 and effect size of 0.61. Results: Hundred percent clinical success with ultrasonic plasticized group and 95.2% success with preheated composite resin group were observed without statistical significance. Conclusion: The ultrasonics plasticization of composite resin demonstrated comparable results with that of preheated composite resin after 6- and 12-month recall. Use of vibration energy utilizing the thixotropic effect might have resulted in better clinical performance.

Comparative evaluation of the effect of adhesive restorative composite resins on the reinforcement of peri-cervical dentin: An in vitro study.

Background: Peri-cervical dentin (PCD) and its reinforcement play a crucial role in the fracture resistance of root canal-treated teeth. Aims: The aim of this study was to compare the fracture resistance of dual-cure, nano-hybrid, and short-fiber reinforced composite resins restored PCD with conventional hybrid composite (CHC) resin restored endodontically treated mandibular premolars. Settings and Design: Academic, in vitro study. Materials and Methods: The prepared mandibular premolar samples were randomly divided into five groups of 10 each. In Group 1, teeth were left intact. The remaining 40 teeth were endodontically treated and obturated as follows: In Group 2, teeth were obturated with gutta-percha till cementoenamel junction and restored with CHC. Teeth in Groups 3, 4, and 5 were obturated to a depth of 5 mm from the cervical line and restored with dual-cure, nano-hybrid, and short-fiber reinforced composite resins, respectively. Fracture resistance was tested using a universal testing machine. Statistical Analysis Used: One-way analysis of variance and post hoc Tukey's test. Results: Short-fiber reinforced composite resin showed a significantly higher mean fracture resistance value compared with other experimental groups. The mean fracture resistance values were obtained as Group 1 > Group 5 > Group 4 > Group 3 > Group 2. Conclusions: Reinforcement with short-fiber reinforced composite showed significantly higher fracture resistance compared with nano-hybrid and dual-cure composite resins.

Comparative evaluation of efficacy of three single file retreatment systems for removal of gutta percha and assessment of root canal transportation - An In Vitro study.

Background: In comparison to multiple file systems, recent advancements in single file retreatment systems had reduced the working time and ease of operation for clinicians. Aim: To compare the efficacy of retreatment systems compared with hand instrumentation, by evaluating their removal efficacy, time required for retreatment and assessment of canal transportation. Methods and Material: Forty premolars were instrumented using ProTaper Gold gold files. Post instrumentation, scan was taken, obturated using warm vertical compaction technique, and stored in artificial saliva for three months and randomly divided into four groups for retreatment. Hand instrumentation (Hi), Neoniti (Nn), Mtwo R (Mt), WaveOne Gold (Wg). Post retreatment, scan was taken. Teeth were sectioned longitudinally and photographed under the stereomicroscope. Retreatment time was recorded, and canal transportation was calculated. Statistical Analysis: The results were analyzed using one-way analysis of variance (ANOVA) followed by Tukey's post hoc test at 95% confidence level. Results: The retreatment time was significantly longer in the Hi group. Within the test groups, a significantly longer time has been taken by Wg (p < 0.05) compared to Mt and Nn. There was no difference in the canal transportation between the single file systems at 3 mm, 6 mm and 9 mm from the apex, there was statistically significant higher transportation for the Hi group at 9 mm from the apex (p < 0.05). Conclusions: All techniques were effective in removal of filling material with minimal canal transportation. Wg system was shown to increased time compared to Nn and Mt systems. Hi group was slowest with maximum canal transportation at 9 mm from the apex.

Comparative evaluation of chlorhexidine, grape seed extract, riboflavin/chitosan modification on microtensile bond strength of composite resin to dentin after polymerase chain reaction thermocycling: An in vitro study.

AIM: The purpose of this study was to evaluate the influence of chlorhexidine (CHX), grape seed extract (GSE), riboflavin/chitosan modification on microtensile bond strength (µTBS) of composite resin to dentin after polymerase chain reaction (PCR) thermocycling. MATERIALS AND METHODS: Forty extracted human molars were used and a flat surface was then prepared by removing the occlusal one-third. The teeth were randomly assigned into four groups - Group I in which self-etch adhesive (Adper Easy One) was applied and Groups II, III, IV were pretreated with 2% CHX, 6.5% GSE, and 1% riboflavin/chitosan, respectively, before the application of self-etch adhesive. Composite build-ups were constructed, and PCR thermocycling (5000 cycles) was performed. The µTBS was evaluated using the universal testing machine. Data were analyzed using one-way analysis of variance and Tukey's test. RESULTS: The mean µTBS values for Group I (control), Group II (CHX), Group III (GSE), and Group IV (riboflavin/chitosan modification) were 30.81, 43.15, 38.79, and 35.07 MPa, respectively. CONCLUSION: Pretreatment with CHX and GSE leads to a significant increase in µTBS of composite resin to dentin.

A comparative evaluation of the increase in root canal surface area and canal transportation in curved root canals by three rotary systems: A cone-beam computed tomographic study.

AIM: The aim of this study was to measure the increase in root canal surface area and canal transportation after biomechanical preparation at 1, 3, and 5 mm short of the apex with three different rotary systems in both continuous rotary and reciprocating rotary motions. MATERIALS AND METHODS: Sixty freshly extracted human mandibular molars with mesial root canal curvatures between 20° and 30° were included in the study. Teeth were randomly distributed into three groups (n = 20). Biomechanical preparations were done in all the mesial canals. In Group 1, instrumentation was done with ProTaper universal rotary files, Group 2, with K3XF rotary files, and Group 3, with LSX rotary files. Each group was further subdivided into subgroups A and B (n = 10) where instrumentation was done by continuous rotary and reciprocating rotary techniques, respectively. Increase in root canal surface area and canal transportation was measured using the preoperative and postoperative cone-beam computed tomography scans. STATISTICAL ANALYSIS: The data were analyzed by one-way ANOVA followed by Tukey pairwise multiple comparison tests. RESULTS: Increase in root canal surface area was significantly more (P < 0.05) in ProTaper and K3XF groups when compared to LSX group. Canal transportation was significantly more (P < 0.05) in ProTaper group when compared to K3XF and LSX groups. There was no significant difference (P > 0.05) in increase of root canal surface area and canal transportation between continuous rotary and reciprocating rotary techniques for ProTaper Universal, K3XF and LSX groups. CONCLUSION: LSX rotary system showed minimal increase of root canal surface area and minimal canal transportation when compared to ProTaper and K3XF rotary systems.

Evaluation of the Quality of Obturation with Obtura at Different Sizes of Apical Preparation Through Microleakage Testing.

INTRODUCTION: Obturation of the root canal system is required to prevent recontamination of the root canal after cleaning and shaping procedures and to seal the root canal completely, both the apical and coronal avenues of potential leakage and to maintain the disinfected status. AIM: The aim of this study was to determine the microleakage by dye leakage method at 1mm, 3mm and 5mm short of the apex with different sizes of apical preparation, obturated by Obtura. MATERIALS AND METHODS: Sixty freshly extracted human single rooted teeth were randomly distributed into six equal groups. Group I (control group) was obturated by lateral compaction technique. Group II to VI were experimental groups (apical preparations done upto ISO sizes 20, 30, 40, 50 and 60 respectively), obturated by Obtura technique. After storing the samples at 100% humidity for seven days and one day in 2% methylene blue, the roots of the teeth were sectioned at 3mm short of the apex. They were observed under stereomicroscope at 20X magnification and the images were analysed for microleakage using the scoring criteria. The data obtained were analysed by One-way ANOVA followed by Tukey pair-wise multiple comparison test and p ≤ 0.05 was considered as the level of significance. RESULTS: The lowest mean microleakage score was seen in Group VI (0) and the highest mean leakage score was seen in Group II (1.5). There was statistically significant difference between Group II and Group V (p = 0.044), Group II and Group VI (p = 0.013). There was no significant difference between all the other groups (p> 0.05). CONCLUSION: Comparison of microleakage between different groups from ISO sizes 20-60 recommends a minimum apical preparation of ISO size 30.

A novel approach for restoration of hemisectioned mandibular second molar with modified tunnel restoration: a case report.

Hemisection refers to sectioning of a mandibular molar into two halves followed by removal of the diseased root and its coronal portion. Hemisection of a mandibular molar may be a suitable treatment option when the decay is restricted to one root and the other root is healthy. The retained root is endodontically treated and the furcation area is made self-cleansable. Retained tooth structure is restored as premolar which helps to reduce the masticatory load. Hemisection of mandibular molar was often referred to as premolarization. Studies showed that the remaining coronal structure influenced the fracture resistance of endodontically treated maxillary first premolars. Clinical experience showed the viability of tunnel restoration as an alternative to class II conventional cavity preparation in initial proximal lesion. This article discusses a case that presents the novel technique involved in restoration of the remaining hemisected tooth using modified tunnel restoration.