Proximal contact tightness of direct Class II composite resin restorations with various matrix systems: A systematic review.

Background: Restoring an ideal proximal contact in direct Class II composite resin restorations is challenging due to polymerization shrinkage, absence of condensability of composite materials, thickness of matrix bands, and the use of various separation techniques, retainers, and bands. Aims: The aim of this study was to evaluate the proximal contact tightness that is achieved by various matrix systems used to restore a direct Class II cavity with composite resin restoration. Methods: A systematic review was carried out according to the PRISMA 2020 statement guidelines. The online search for the articles was done in electronic databases of MEDLINE/PubMed, Cochrane, and Google Scholar. The articles comparing different matrix systems for restoration were selected. Out of 146 articles, a total of 6 articles met the selection criteria and were included. The QUIN risk-of-bias (RoB) tool was used for assessing the study quality. The data extracted from full text articles selected for inclusion, using a standardized software (Office Excel 2013 Software, Microsoft Corporation, Redmond, WA, USA). Results and Conclusion: Combination of sectional matrices and separation rings resulted in tighter proximal contact compared to other matrix systems.

A three-dimensional finite element analysis of stress distribution in maxillary central incisor with a horizontal mid root fracture after various management protocols.

Context: The incidence of root fractures is about 1.2%-7% in permanent teeth and horizontal mid root fractures are most common in maxillary anteriors. Aims: This study aims to evaluate the stress distribution in a maxillary central incisor with mid root fracture after various management protocols using three-dimensional finite element (FE) analysis. Materials and Methods: Four three dimensional FE models were constructed: Model 1-Normal tooth, Model 2-tooth with horizontal mid root fracture, Model 3-tooth with horizontal mid root fracture, coronal fragment filled with Biodentine, and access cavity sealed with composite resin cement and apical fragment left untreated and Model 4-tooth with horizontal mid root fracture restored with intraradicular fiber post as a splint and access cavity sealed with composite resin cement. The properties of materials were assigned and a force of 100 N was applied at 45° angle to the longitudinal axis of the tooth onto the palatal surface incisal to the cingulum. Statistical Analysis: Von-Mises stress along the length of the root analyzed and compared. Results: The maximum stress distribution was observed at the palatal end of the coronal radicular fragment in both without treatment and with biodentine treatment. The stress distribution was concentrated more at the junction of the splinted area in the intraradicular fiber post splinted model. Conclusions: The model with intraradicular fiber post as a splint exhibited more stress concentration at the splinted area due to bending forces. These stresses may adversely affect the healing around the fracture site and affect the longevity.

Comparative evaluation of apical bacterial extrusion following root canal instrumentation using different endodontic file systems: An in vitro study.

AIM: This study aims to evaluate the amount of apical extrusion of bacteria during root canal instrumentation using K3XF, Protaper Gold, Edge taper platinum, and Hyflex CM Rotary systems. MATERIALS AND METHODS: Sixty freshly extracted maxillary incisors teeth collected in saline. Access cavity prepared and canals were made free of bacterial and pulp. The teeth were mounted on the bacteria collecting apparatus. Root canals were contaminated with the Fusobacterium Nucleatum (ATCC25586) and dried at 37°C for 24 h. In Group 1 (Control group): No instrumentation was done and biomechanical preparation done in all other groups with Group 2: Hand K-files, Group 3: Protaper gold, Group 4: K3XF, Group 5: Edge taper platinum, and Group 6: Hyflex CM rotary file systems. Then, the extrude was collected, and it is incubated in Mueller-Hinton agar for 24 h and the number of colony forming units were counted and statistical comparison was done using Kruskal-Wallis test and Mann-Whitney U test. RESULTS: Hand K-files extruded more bacteria when compared to other four rotary systems, K3XF file system extruded least number of bacteria. CONCLUSION: All instrumentation techniques extruded intracanal bacteria apically. However, engine-driven nickel-titanium instruments extruded less bacteria than the manual technique. The K3XF rotary file system comparatively extruded less bacteria than other rotary file systems.

Evaluation and comparison of sealing ability of three different obturation techniques - Lateral condensation, Obtura II, and GuttaFlow: An in vitro study.

AIM: To evaluate and compare the sealing ability between the conventional cold lateral condensation technique and two different obturating techniques - Obtura II and GuttaFlow under a stereomicroscope at 40× magnification. MATERIALS AND METHODS: Sixty single-rooted teeth were selected and the canals were shaped with ProTaper rotary files. Irrigation was performed with 5% sodium hypochlorite and 17% EDTA. The teeth were then separated into three groups depending on the type of obturation technique. Group A (n = 20) - obturated using the Lateral condensation technique and AHplus sealer, Group B (n = 20) - obturated with Obtura II injection-molded thermoplasticized technique and AHplus sealer, and Group C (n = 20) obturated using GuttaFlow. After storing the teeth in 100% humidity for seven days at 37°C, the roots of the teeth were sectioned at five levels. The sections were then observed under a stereomicroscope at 40 × magnification and the images were analyzed for area of voids (AV) and frequency of voids. STATISTICAL ANALYSIS USED: The data was statistically analyzed using the SPSS version 17 software. The 95% confidence intervals (CI) were calculated. One-way analysis of variance with post-hoc test and non-parametric Mann-Whitney U test was carried out, to compare the means. RESULTS: The lowest mean of AV was recorded in the Obtura II group, 1.0% (95% CI = 0.5 - 1.5). This was statistically and significantly different from the GuttaFlow group, 3.0% (95% CI = 2.1 - 3.9). There was no significant difference between the Obtura II group and the lateral condensation group, 1.6% (95% CI= 1.0 - 2.2) with regard to the area of voids, but there was a statistically significant difference between the Lateral condensation and GuttaFlow groups. The GuttaFlow group showed the maximum number of voids, 56% (95% CI = 48 - 64), which was significantly higher than those in the lateral condensation, 26% (95% CI= 19 - 34), and Obtura II, 15% (95% CI= 10 - 21) groups. CONCLUSION: The Obtura II technique utilizing the injection-molded thermoplasticized gutta-percha had better adaptability to the canal walls when compared to the GuttaFlow obturation and lateral condensation techniques.