COMPARING THE EFFECT OF LASER BLEACHING WITH HOME BLEACHING ON PAAN STAINED TEETH USING DIGITAL SPECTROPHOTOMETER

Introduction: The demand for tooth whitening has increased dramatically with the resulting development of new tooth whitening products and procedures. As it is a common scenario that the dentists come across paan stained teeth very regularly in dental practice, the need for this study is to compare if laser bleaching or three day home bleaching is effective for paan stained and give better treatment options for patients. Aim: To compare the effect of laser bleaching on paan stained tooth with home bleaching tooth using digital spectrophotometer Methodology: 20 extracted teeth were preserved in a solution of normal saline with 1% thymol crystals. The teeth were immersed in staining solution containing paan extracts for a period of two week. The specimens were evaluated for pre shades using VitaEasyShade. The stained specimens for paan respectively were divided randomly into 2 groups one for laser bleaching and other for home bleaching. POLA OFFICE + was applied on tooth and activated using the diode laser as per the manufacturer’s instructions for group 1. The bleaching was carried out with Philips Zoom Nitewhite for group 2. The second colour measurement of the specimens was made using VitaEasyShade. Conclusion: The results showed that laser bleaching was effective when compared to three day home bleach in paan stained teeth using digital spectrophotometer.

Effect of Three Wavelengths of Diode Laser on the Efficacy of Bleaching of Stained Teeth

Objectives: Light irradiation and heat have been used to accelerate the process of tooth bleaching. This study aimed to assess the efficacy of conventional bleaching compared to laser-bleaching using three different wavelengths of diode lasers. Materials and Methods: In this in-vitro experimental study, 40 extracted human central incisors were immersed in a coloring solution made of tea, coffee, and cola for 21 days. The L*, a*, and b* color parameters were measured before and after the immersion using spectrophotometry. The teeth were then randomly divided into four groups (n=10) as follows: group 1: 810-nm diode laser + Biolase Laser White 20, group 2: 940-nm diode laser + Biolase Laser White 20, group 3: 980-nm diode laser + Biolase Laser White 20, and group 4: conventional bleaching with Opalescence Boost without laser irradiation. One-way analysis of variance (ANOVA) was used to assess the effect of laser type and bleaching technique on color parameters. Results: The 940-nm (∆E=28.5896) and 810-nm laser groups (∆E=21.2382) showed the highest and the lowest bleaching efficacy, respectively; however, the groups were not significantly different in terms of bleaching efficacy (P>0.05). Conclusion: Laser-bleaching with 810-, 940- and 980-nm wavelengths of diode laser has an efficacy similar to that of conventional bleaching but in a shorter period. No difference was noted between different laser wavelengths in terms of bleaching efficacy.

Comparative Study on the Effects of Laser Bleaching and Conventional Bleaching on the Physical Properties of Indigo Kapok/Cotton Denim Fabrics

Kapok is a hollow fiber with a 90% hollow degree. Compared with cotton fiber, kapok fiber has excellent performances, such as good hygroscopicity, and a good warmth retention property. In this work, desized indigo kapok/cotton denim fabrics were bleached in different ways: Laser, cellulose enzyme, sodium hypochlorite, potassium permanganate and hydrogen peroxide. After bleaching, the K/S values, tensile strength, air permeability, thickness, color fastness to rubbing and the crease recovery angle of denim fabrics were measured through the spectrophotometer, tensile strength tester, air permeability tester, thickness tester, rubbing fastness tester and fabric crease elasticity tester, respectively. The surfaces of fabrics and fibers were observed by scanning electron microscopy (SEM). Results show that the kapok/cotton fabrics were color-faded after five kinds of bleaching, the K/S values of denim with laser bleaching was declined dramatically, while there was a little change in the permeability. The tensile strength and the weight of the fabrics were decreased, and cloth which was bleached with potassium permanganate was most affected. The color fastness to rubbing and the crease recovery angle of denim fabrics with laser treatment is most suitable for industrial production. In general, laser bleaching is the better way to fade the kapok/cotton denim fabrics. Meanwhile, after five kinds of bleaching, the physical properties of kapok/cotton denim fabrics were similar to those of cotton denim fabric, which indicates that kapok/cotton denim fabric is suitable for the existing industrial bleaching technology.

Using Confocal Laser Scanning Microscopy to Study an Ambers, a New Approach

Currently, in the scientific literature, there is no a sole opinion on mechanisms governing phenomenon of blue amber. In specimens sampled in Dominican Republic it is caused by presence of perylene; whereas, specimens sampled in northern Spain this has not been confirmed. We have obtained specimens from a third, earlier not studied, source of blue amber in the Far East of Russia that was described in 2015. This sample was investigated with a laser confocal microscopy and a laser bleaching studies. We found fluorescence pattern that is typical for perylene and bleaching showed rapid diffusion that is consistent with the perylene hypothesis. Moreover we demonstrate that confocal laser scanning microscopy could be successfully used for rapid search of the organisms in the dark part of the amber samples.

Effect of Er: YAG Laser on Microtensile Bond Strength of Bleached Dentin to Composite

Introduction: In non-vital tooth bleaching, dentin is in direct contact with the bleaching agent, 1 to 3-week delay is needed to eliminate free radicals from tooth structure. The present study aimed to evaluate the effect of irradiation of Er: YAG laser on immediate microtensile bond strength of bleached dentin to composite. Methods: Sixty sounds human teeth were collected and randomly divided into 4 groups (n=15): no bleaching (NB), opalescence endo hydrogen peroxide (HP) gel bleaching, sodium perborate (SP) bleaching and laser bleaching with heydent gel (LB). The groups were divided into 3 subgroups (n=5): no surface treatment, Er: YAG laser irradiation and 10% sodium ascorbate (SA). All samples were restored and underwent microtensile bond strength testing. Statistical analysis was carried out using one-way and two-way ANOVA. Results: Bond strength in NB-SA group had a significant difference with the NB group (P<0.05) while no significant difference was noted between NB and NB-Er groups (P=0.55). Application of SA and Er: YAG laser after bleaching with SP did not enhance the bond strength (P=0.07). Conclusion: Application of SA and Er: YAG laser after HP gel bleaching significantly enhanced the bond strength. Application of Er: YAG laser after internal bleaching with HP gel could enhance the bond strength.

Evaluation of biochemical changes in dental tissues after different office bleaching methods

The color of the teeth is an important topic for many people and can be influenced by intrinsic and extrinsic stains. There is an increasing demand for whitening of the teeth year by year. The most popular way of whitening is “bleaching,” which is the result of the breakdown of pigments located in the enamel and/or the dentin, caused by reactive oxygen species (ROS) released from bleaching agents. These bleaching agents could increase matrix metalloproteinase (MMP)-mediated collagen degradation in dentin. The aim of this study was to compare biochemical changes and oxidative stress levels of the human premolar dentin–pulp complex after three different bleaching methods containing hydrogen peroxide (H2O2) bleaching agents. Individuals, whose first four premolars were extracted for orthodontic purposes, included into the study. Group 1—Laser: bleaching gel containing 46% H2O2 (LaserWhite20 whitening gel, Biolase Technology Inc., San Clemente, CA, USA) and a diode laser activation (Ezlase 940 nm system). Group 2: 35% H2O2 containing whitening gel (Whiteness HP Maxx, FGM) and halogen light source activation (Optilux 501, Kerr, Orange, CA, USA). Group 3: 35% H2O2 containing whitening gel (Whiteness HP Maxx, FGM). Group 4—Control: No whitening treatment. According to the test results, there were no significant differences among groups in the values of cathepsin B and MMP proteolytic activities ( p > 0.05). The total ROS values released from the dentin tissue were higher than those obtained from the pulp tissue ( p < 0.05). There were significant differences among the bleaching groups in the ROS values released from the dentin tissue.