Measure and compare the Degree of Root Canal Transportation and Canal-centering ability of Twisted, ProTaper, and Conventional Stainless Steel K Files using Spiral Computed Tomography: An in vitro Study.

AIM: The aim of this study was to compare canal transportation and centering ability of Twisted files (TF) and ProTaper (PT) files with conventional stainless steel (SS) K files. MATERIALS AND METHODS: Thirty mandibular premolar teeth with root curvature of 25 to 35° were selected. The samples were randomly divided into three groups of 10 each according to the type of files used for instrumentation. Group I was instrumented using TF, group II with PT files according to the manufacturer's recommendations, and group III with samples prepared with pre-curved SS K files using a step-back technique. After preparation, the samples were assessed using spiral computed tomography. Three sections were recorded at coronal, middle, and apical levels. Amount of transportation was assessed comparing with preinstrumentation images. Centering ability was calculated using Gambill's formula. The three groups were statistically compared using Student's t-test. RESULTS: Twisted files showed the least canal transportation and the best centering ability followed by PT file system. Stainless steel K files showed the highest transportation and least centering ability. CONCLUSION: Twisted files showed the least amount of transportation and better centering compared with the other file systems. CLINICAL SIGNIFICANCE: The study gives information of TF, a recently introduced rotary system (2008) with regard to its efficacy in preparing curved root canals. This study has shown that the centering ratio of rotary nickel titanium was better than that of SS files.

Comparative Evaluation of Effect of Nano-hydroxyapatite and 8% Arginine Containing Toothpastes in Managing Dentin Hypersensitivity: Double Blind Randomized Clinical Trial.

PURPOSE: This double blind randomized clinical trial was conducted with the purpose of evaluating the effects of Nano-hydroxyapatite toothpaste as compared to 8% Arginine containing toothpaste in the management of Dentin hypersensitivity (DH). METHOD AND MATERIALS: Patients (30 in each group) suffering from DH and eliciting a VAS score higher than 2 in air blast and tactile test were randomly allocated (block randomization) into either a group 1 (arginine toothpaste) or group 2 (nHA toothpaste). The primary outcome evaluated was the reduction of DH as measured by the electrical stimulus reading on the digital pulp tester. Current required for eliciting a VAS score of 2 was recorded before application of dentifrice. 1 cm of toothpaste was then expressed on the tooth surface for two minutes in each group and rinsed off. The electrical stimulus required to elicit a VAS score of 2 was recorded after 5 minutes, 1 week and 4 weeks. RESULTS: The desensitizing paste containing arginine provided a statistically significant reduction in DH and so did the paste containing nHA. Mean increase in amperage value (reduction in DH) was higher for nHA based than the arginine containing dentifrice. This difference was not statistically significant showing that both toothpastes are equally effective. CONCLUSIONS: The findings of the present study encourage the use of Nano-hydroxyapatite and arginine containing dentifrice as an effective desensitizing agent providing relief from symptoms 5 minutes after application and after 1 and 4 weeks.

Evaluation of the effect of different food media on the marginal integrity of class v compomer, conventional and resin-modified glass-ionomer restorations: an in vitro study.

BACKGROUND: Cervical lesions of anterior and posterior teeth are a common finding in routine dental practice. They are of much concern to the patient, if present in esthetically sensitive regions. Adhesive tooth-colored restorative materials are generally recommended for treating such lesions. The aim of the present study was to evaluate and compare the effect of various food media (lime juice, tea, coffee, and Coca-Cola) on the marginal integrity of Class V compomer (Dyract(®)), conventional glass-ionomer (Fuji II) and resin-modified glass-ionomer (Fuji II LC improved) restorations along their cemental and enamel margins with saline as control media. MATERIALS AND METHODS: After restoration of prepared Class V cavities in human premolars with the three different materials (n = 8), they were immersed in the test media for 7 days and then stained with methylene blue dye. Buccolingual sections were prepared and examined under stereomicroscope and scores (0-2) were given. RESULTS: Data were analyzed statistically using one-way analysis of variance in SPSS version 16.0. P < 0.05 were considered statistically significant. CONCLUSIONS: Among the three tested materials Compomer (Dyract(®)) showed more marginal integrity than the other two. Micro leakage values of Fuji II and Fuji II LC improved were statistically significant in acidic media (lime juice and Coca-Cola) compared to saline. Enamel margins showed more marginal adaptation than cemental margins.