Antibacterial Effect of Silver Nanoparticle Gel as an Intracanal Medicament in Combination with Other Medicaments against Enterococcus faecalis: An In vitro Study.

BACKGROUND: Bacteria and their by-products are responsible for various pulpal and periapical infections which can be classified as biofilm-mediated infections. Recently, nanoparticles have been introduced to decrease the bacterial load in endodontic infections. AIM AND OBJECTIVES: The aim of the study was to compare and evaluate the antibacterial effect of silver nanoparticles alone and combination of silver nanoparticles with calcium hydroxide and chlorhexidine against Enterococcus faecalis. MATERIALS AND METHODS: A pure culture of E. faecalis was used as the test microorganism. After 24 h of incubation the bacterial colonies were isolated and suspended in 5 ml of infusion broth followed by incubation at 37°C for 4 h. 0.5 McFarland of the bacterial suspension was prepared and then cultured on Mueller-Hinton agar culture medium with the help of a sterile swab. In each culture plate, five wells were created with a sterile pipette for placement of the samples. RESULTS: Statistically significant difference in the antibacterial effect of the combination of silver nanocure gel with various medicaments was observed when compared to the effect of silver nanocure gel alone. Silver nanocure gel in combination with calcium hydroxide (Group B) was more efficacious as compared to silver nanocure gel alone (Group A) (P < 0.001). Antibacterial activity of silver nanocure gel in combination with chlorhexidine (Group C) was also significantly higher than silver nanocure gel alone (P < 0.001). CONCLUSION: The present study is an in vitro study, in which we concluded that the combination of all the intracanal medicaments is the best among for elimination of E. faecalis biofilm from the root canal. The above findings need to be tested in vivo also.

Evaluation of the Flexural Strength of Submicron Hybrid Composite using Different Fabrication Methods: An in vitro Study.

AIM: The aim of this study is to perform three-point bend test on submicron hybrid composite fabricated with direct and indirect veneer technique. MATERIALS AND METHODS: A total of 20 maxillary anterior teeth were selected, and labial reduction of 0.5 to 0.75 mm with a chamfered finish line for veneer preparation was done. Teeth were divided into two groups depending on fabrication technique being used: group I-veneers fabricated with light and group II-veneers fabricated with light and heat (PHOTOPOL). Specimens were tested under universal testing machine (UTM) where load was applied at a crosshead speed of 1 mm/min with a pointer of 1 mm diameter. Data were statistically analyzed. RESULTS: The results showed highly significant difference between the two groups with the mean value of group I (246.7 ± 2.285 N) and group II (531.1 ± 4.411 N). CONCLUSION: The curing mechanism involving light and heat increases the fracture resistance of the veneers. CLINICAL SIGNIFICANCE: Within the limitations of this study, the results led to the conclusion that the association of common composites with a simple postcure heat treatment may be an alternative for current indirect composite systems, although more studies are needed to assess other properties of the composites for this application.

Quantitative Assessment of apically Extruded Bacteria using different Instrumentation Techniques and Preparation Taper.

BACKGROUND: Cleaning and shaping of the pulp canal is one of the most important steps of endodontic therapy. Serious complications occur by the apical extrusion of bacteria during the instrumentation procedures. Both crown-down (CD) and full-length linear motion (FM) techniques are routinely used as a component of taper rotary instrument procedures for achievement of thorough cleaning and shaping of the pulp canal space. Hence, we aimed for this study to assess the change in the amount of apically extruded bacteria using CD and FM instrumentation techniques produced by differences in taper between the instruments used during biomechanical preparation of root canals. MATERIALS AND METHODS: The present study included assessments of 132 extracted maxillary central incisor teeth. To achieve a uniform teeth length of 21 mm, the height of the tooth crown was reduced for preserving the coronal portion of teeth. A modified glass vial model was constructed for the estimation of amount of bacterial extrusion through the apical region. For filling of each pulp canal specimen, 20 mL of Enterococcus faecalis suspension was used followed by the use of a number 10 K-file for carrying the bacteria down the lengths of pulp canals. All the contaminated teeth specimens were divided into six study groups with groups I to III containing specimens prepared in the CD manner, while groups IV to VI contained specimens prepared in the FM manner. Six teeth were taken as negative control with three specimens with each technique, and another six specimens were taken as positive controls. Cultivable bacterial counts were determined by evaluating 100 mL saline solution from each vial followed by its inoculation on blood agar. All the colony-forming unit (CFU) values were log-transformed (base 10), and the results were analyzed by Statistical Package for the Social Sciences software. RESULTS: A significantly lower quantity of CFU values was observed during CD instrumentation procedures with 0.02 files in comparison with all other study groups. However, while comparing both the instrumentation procedures when different taper files, other than 0.02 taper, were used for biomechanical preparation of root canal, nonsignificant results were obtained. CONCLUSION: With 0.02 taper preparations, significantly less amount of extrusion of bacteria is associated when done with CD technique. CLINICAL SIGNIFICANCE: No change in the amount of apical extrusion of bacteria will be seen by changing the type of instrumentation procedures. Amount of bacteria extruded can be minimized using 0.02 taper. Key words: Bacteria, Instrumentation, Taper.

Retrospective Assessment of Healing Outcome of Endodontic Treatment for Mandibular Molars with C-shaped Root Canal.

INTRODUCTION: A thorough knowledge of the anatomic morphology of the root canal system is necessary for the long-term success of the root canal therapy. The occurrence of C-shaped root canal configuration is one such variation. Achievement of favorable prognosis after commencing root canal therapy in such teeth is one of the challenges imposed on the endodontist. Hence, we evaluated the healing occurring after endodontic therapy in patients with C-shaped root canals in mandibular molars. MATERIALS AND METHODS: The present study was conducted in the Department of Conservative Dentistry of the institution and included assessment of all the patients who underwent root canal treatment of the mandibular first and second molars. Endodontic therapy was performed in all the cases by experienced endodontist. Final postoperative radiographs were taken. Recording of the data of the personal and clinical details of a total of 250 patients was done. All the clinical and radiographic details of the patients, such as tooth location in the jaw, presence or absence of C-shaped canals, status of the pulp tissue, presence or absence of the fractures, and other details of the patients were recorded. Radiographic and clinical examination of the tooth of the patients was done during the baseline visit and further during the follow-up visits. The presence of C-shaped root canals was confirmed using the radiographs. Periapical index (PI) scoring system was used. Categories defined for enlisting the healing after the root canal treatment with the assessment of the PI score. All the results were analyzed by Statistical Package for the Social Sciences software. RESULTS: Vital pulp tissue was encountered in majority of the cases. C-shaped root canal configuration was observed in 40% of the cases included in the present study. After completion of the endodontic therapy, complete crown placement was done in only 22% of the cases. In cases of vital teeth with C-shaped root canals configuration, most of the teeth showed complete healing. Significant results were obtained while comparing the complete coverage crown parameter in relation to the healing process in teeth with C-shaped root canals. CONCLUSION: In the present study, no significant effect of the C-shaped root canal configuration was found on the healing rate of the endodontic therapy in mandibular molars. CLINICAL SIGNIFICANCE: Meticulous endodontic therapy with special techniques should be done while preparing teeth with C-shaped root canals.