In-Office Bleaching Techniques: Laboratory Investigation of the Effect on Color Change and EnamelMicromorphology

Abstract

Objectives: This study was conducted to evaluate and compare the effect of different in-office bleaching techniques on color change and enamel surface micromorphology. Materials and Methods:Three different bleaching agents(one light-activated and two chemical-activated) were selected for this study. Sixty sound human permanent maxillary central incisors were selected andfixedin cylinder plastic mold (2 cm width and 1cm height) fabricated with using selfpolymerized acrylic resin.Teeth were assigned into two groups according to the test conductedon, color test group (n=30), and themicro-morphology test group(n=30). Each group was further classified into three subgroups(n=10) according to the bleaching material used. The subgroups of each bleaching material were tested for enamel color change assessment usingaspectrophotometer and for surface micromorphology assessment by a non-contact optical profilometer before and after bleaching application. Data for each test wastabulated and statistically analyzed. Results: Regarding color change analysis,all tested bleaching materials were effective on tooth color whitening,there was statistical significant differenceinthe mean value of all tested groups (P=0.011). With higher mean values recorded for Zoom group followed by Dash and Boost groups. Regarding the results of surface micromorphology, all the tested bleaching materials showed no statistical significant difference in enamel surface roughness after bleaching(P=0.591). Conclusions: All thetestedin-officebleaching systemswere effectivelywhiten teeth, with light-activated systemexhibited higher whitening potential than chemical-activatedbleaching systems, with insignificant changein enamel micromorphology. In-Office Bleaching Techniques: Laboratory Investigation of the Effect on Color Change and EnamelMicromorphology Mansoura Journal of Dentistry 2021;8(29):17-21. 18 Muazaz Fawzi Hamed have found alterations in surface morphology, calcium loss and changes in chemical composition of enamel. 18-20 Thus, this study was performed to evaluate the effect of three different in-office bleaching systems on color change and enamel micromorphology. Aim of Study This study was intended to evaluate and compare the effect of different in-office bleaching techniques on the color change and enamel surface micromorphology. Null hypothesis This study was conducted to testthe null hypothesis that, the tested in-office bleaching techniquesneither differ in its bleaching efficacy nor in changingthe enamel micromorphology. I. Materials and Methods Three different types of commercially available in-office teeth bleaching materials which are; one light-activated bleaching agent (Zoom) and two chemical-activated agents (Opalescence X-tra Boost, Dash)were used in this study. A total number of 60 human permanent incisors extracted due to periodontal diseases were obtained from Outpatient Clinic, Oral Surgery Department, Faculty of Dentistry at Mansoura University. All collected teeth were examined to be free from any cracks ,defects, and caries. Theywere cleaned from any calculus deposits and attached periodontal tissues using ultrasonic scaler (Guilin Woodpecker, Guangxi, China) and thoroughly washed under running water. Specimen preparation Each tooth was transversely sectioned at the cementoenamel junction by means of a diamond instrument (Isomet, Buehler, USA) and the root was discarded. For easy holding and to prevent any possible contamination during application of bleaching agents, each tooth was fixed in polyvinyl chloride (PVC) mounting cylinder plastic mold of 2 cm width and 1cm height, utilizing self-polymerized acrylic resin (Acrostone, Egypt). The blocks were numbered for each group by correction pen (water proof, china)(Figure2). Study design The 60 prepared specimens were divided into two groups corresponding to the test conducted on, color change test group (n=30), and the micro-morphology test group(n=30). Each group was further divided into three subgroups(n=10)according to the bleaching material used (Figure 3). Bleaching techniques  Zoom (Light-activated bleaching agent) Zoom gel was applied on the labial surface of each tooth by supplied brush in a layer thickness of 1-2 mm according to manufactures instructionsfor 3 cycles,each of them was15 minutes. The gel was activated by using Philips Zoom speed light device that was applied for15 minutes to the teethfor each cycles.  Dash (Chemical-activated bleaching agent) The dash chemical accelerator was applied on the labial surface of each tooth followed by the dash bleaching gel. The bleaching gel was applied in a layer of thickness 1-2 mm according to manufactures instructions and remained on the teeth for15 minutes for the three sessions for each tooth.  Opalescence X-tra Boost (Chemical-activated bleaching agent) Opalescence X-tra boostbleaching gel wasexpresseddirectly onto the labial surface ofeach tooth ; in a layer thickness of approximately 1-2 mm; according to manufactures instructions. Before using, syringes were joined together, dry material was introducedfrom its syringe into the syringe comprising the hydrogen peroxide, the produced mixing bleachingmaterial then expressed back and forth from one syringe to another25 times to be completely mixed. After mixing, syringes were detached and the mixture was expressed directly onto the labial surface of the teeth.Bleaching gel was remained on the teeth for15 minutes of three sessions for each tooth.