Effect of Nano-Pulsed Cold Laser (NPCL) Light on Calcium and Phosphate Loss from Dental Enamel During In-office Bleaching with High Concentrated Hydrogen Peroxide Using Atomic Absorption Spectophotometer

To assess calcium and phosphate loss from enamel using 37.5% hydrogen peroxide (HP) gel with additional application of light emitting diode (LED), Diode laser and Nano-Pulsed Cold laser (NPCL) light sources compared to that of 37.5% HP alone using atomic absorption spectrophotometer (AAS). Methods: Twenty teeth were sectioned to obtain mesiobuccal, distobuccal, mesiopalatal and distopalatal specimens. The specimens were randomly assigned to four equal groups. 37.5% HP of 1mm thickness was applied to the enamel surface of each specimen. Each group received three cycles of bleaching of 8 minute’s duration. Group II, III & IV received additional application of LED, Diode laser & cold laser light respectively. Results: Data was analyzed by means of descriptive statistics. Group III showed the maximum loss of ions while Group IV showed the least loss and the differences were statistically significant (P < .05). Conclusion: Teeth treated with 37.5% hydrogen peroxide with application of Nano-Pulsed Cold Laser (NPCL) light presented with significantly minimal calcium and phosphate loss

Evaluation of Centering Ability of Four Thermally Treated Nickel Titanium Rotary Files For Root Canal Preparation In Moderately Curved Root Canals: An Invitro Cone Beam Computed Tomography Assessment

ackground: The ability of an endodontic rotary file to stay centered in the curved root canal system is one of the most important aspects of shaping of root canal as it influences the outcome of the subsequent phases of irrigation, disinfection, obturation and overall success of root canal treatment. Objectives: The purpose of this study was to evaluate root canal centering ability of four thermally treated rotary nickel titanium (NiTi) instrument systems (ProTaper NEXT, ProTaper Gold, Dia-X Files and Neoendo Flex Files) on extracted human teeth. Methods:Forty eight separate mesial root canals from extracted mature mandibular first molars identified with having apical curvature angles of 20°–35° were selected. A cone beam computed tomography (CBCT) was performed and canals were randomly divided into 4 groups of 12 teeth each. Group 1: ProTaper Gold (PTG) rotary files, Group 2: ProTaper NEXT (PTN) rotary files, Group 3: Dia-X (D-X) Rotary Files and Group 4: Neoendo Flex (NE) rotary Files. Root canal instrumentation was performed with all the four NiTi rotary files. Post instrumentation CBCT was performed. Root canal centering ratios were assessed by a standardized technique for individual groups at 9, 6 and 3mm levels of root canals. Results: ProTaper Gold files and Dia-X files resulted in significantly better canal centering ability than the Neoendo files and ProTaper NEXT files. (P<0.05). Conclusion: ProTaper Gold files and Dia-X files exhibited better centering ability than Neoendo files and ProTaper NEXT files at all levels of the root canal.

Ultrasonic Activation of a Bioceramic Sealer and Its Dentinal Tubule Penetration: An In Vitro Study

Background: The root canal sealers form an important component of the three dimensional obturation of the root canals. Moreover, the penetration of the sealers into the dentinal tubules is a desirable phenomenon for their adequate sealing and antibacterial action. The aim of this study was to evaluate the effects of ultrasonic activation on the intratubular penetration of bioceramic root canal sealer. Methods: Eighty extracted human mandibular premolars were divided into 2 groups (n =40) according to the sealer activation method used to obturate the root canals instrumented with F3 Pro-Taper instruments .The canals were obturated using Protaper F3 guttapercha cones. Previously, the bio ceramic sealer was labeled with rhodamine B dye to allow analysis under a confocal microscope. The two groups were: UA (ultrasonically activated) and NA (no activation; control). All samples were sectioned at 3 and 8 mm from the apex. The percentages of dentinal sealer penetration segments of canal were analyzed. Results: Students T test was performed for the statistical analysis and we found that there was a significant increase in tubular penetration for the ultrasonic activation group.Conclusion: Use of ultrasonic activation of a bioceramic sealer promoted greater dentinal sealer penetration.