An Environmental Scanning Electron Microscopy Evaluation on Comparison of Three Different Bleaching Agents using the Laser Activated in-Office Bleaching at Different Wavelengths.

BACKGROUND: Shade of the teeth is of specific significance to the patient because of social and psychological concern and hence plays vital role as primary care. Bleaching is a noninvasive, relatively inexpensive, conservative, and low-maintenance method to change a smile dramatically. AIM: To study the effect of application of three bleaching agents at different wavelengths of laser on the enamel surface of teeth using an environmental scanning electron microscopy (ESEM). MATERIALS AND METHODS: One hundred and twenty freshly extracted, noncarious intact maxillary central incisors were collected and stored in moist conditions in plastic containers. Using a randomized stratified design, the samples were divided into 12 groups (n = 10). The bleaching agent was mixed according to the manufacturer's instructions and applied on the enamel surface of the teeth followed by laser activation. The ultrastructural effects of the bleaching agent on the enamel were determined with an ESEM. Samples were assessed both before and after bleaching on the basis of the degree of surface damage. Because the observation by ESEM was designed to be qualitative, no statistical analysis was performed. RESULTS: JW power bleaching agent and Opalescence Xtra boost showed minimum surface alteration when compared to Polaoffice. Furthermore, the groups treated with diode 810 nm showed less surface damage while neodymium-doped yttrium aluminum garnet 1064 nm more surface alterations than the groups treated with diodes. CONCLUSION: From this current study, it can be concluded that the diode laser of 810 nm with JW power bleaching showed minimum surface alterations.

Shaping Ability of Two-shape and ProTaper Gold Files by using Cone-beam Computed Tomography.

AIM: T-Wire and rotating motion of two-shape (2S), M-wire and rotating motion of ProTaper Gold (PG) are the recent innovations of Nickle Titanium (NiTi) rotary file system by means of thermal treatment. Therefore, a study was planned to assess the shaping ability of 2 Shape and ProTaper Gold using cone beam computed tomography (CBCT) Materials and methods: Thirty freshly extracted mandibular first molars were selected, and Pre-instrumentation CBCT imaging was performed to attain mesial and distal dentin wall measurements followed by chemo-mechanical preparation using the following NiTi files: 2S and ProTaper Gold. Post instrumentation CBCT imaging was performed for evaluation of the volume of removed dentin, apical transportation, and centering ratio. Statistical analysis was confirmed by a suitable analysis test with significance set at 0.05r. RESULTS: In terms of the total volume of removed dentin, apical transportation, and centering ratio there was a significant difference noted between the tow-shape and ProTaper Gold. 2Shape performed better in all aspects compared to ProTaper Gold. CONCLUSION: Two-shape (2S) maintained better original canal anatomy and volume of removed dentin was also less during chemo-mechanical preparation when compared to ProTaper Gold. CLINICAL SIGNIFICANCE: Two-shape (2S) system when used clinically in patients may perform better and produce less canal transportation and canal preparation will be more centered as compared to the ProTaper Gold system.