Colorimeter and Scanning Electron Microscopy Analysis of Teeth Submitted to Internal Bleaching (original) (raw)
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Materials Letters, 2015
Nowadays, there are a number of methods very effectives for the dental bleaching, which are typically strong oxidizing agents, as the hydrogen peroxide, applied directly to the tooth surface. After bleaching, several research studies have been carried out to evaluate the efficacy of bleaching agents on teeth, there being a great controversy concerning the techniques used and their pre-treatment requirements derived, which could alter the final results. In fact, there is a strong necessity to develop different approach to determine the real consequences of bleaching treatment by using an unchangeable and entire tooth. Herein, to evaluate the effects of 38% (p/v) hydrogen peroxide treatment onto morphological, chemical and structural features in the human enamel and dentin, environmental scanning electron microscopy, electron probe micro analyzer and X-ray diffraction techniques have been used. Although such effects have been widely investigated with several techniques, including XRD and SEM, the novelty of this study lies on the techniques and methodology used to characterize the human teeth after bleaching treatment. This approach allows carrying out the analyses without any previous pretreatment, such as powdering, dried or metal sputtering, and its study in the same tooth piece before and after bleaching, which avoids the possible intrinsic differences derived from the use of different pieces. The obtained results display that neither the structural nor the chemical features of both enamel and dentin are altered after bleaching treatment. However, the morphology of the enamel is notably altered, appearing pronounced pores which could affect to the possible bacterial colonization. These findings put an end to the controversies on the different obtained results in the literature of the bleaching effects in the enamel and set standards for future studies.
Evaluation of the bleached human enamel by Scanning Electron Microscopy
Journal of Applied Oral Science, 2005
Since bleaching has become a popular procedure, the effect of peroxides on dental hard tissues is of great interest in research. Purpose: The aim of this in vitro study was to perform a qualitative analysis of the human enamel after the application of in-office bleaching agents, using Scanning Electron Microscopy (SEM). Materials and Methods: Twenty intact human third molars extracted for orthodontic reasons were randomly divided into four groups (n=5) treated as follows: G1- storage in artificial saliva (control group); G2- four 30-minute applications of 35% carbamide peroxide (total exposure: 2h); G3- four 2-hour exposures to 35% carbamide peroxide (total exposure: 8h); G4- two applications of 35% hydrogen peroxide, which was light-activated with halogen lamp at 700mW/cm² during 7min and remained in contact with enamel for 20min (total exposure: 40min). All bleaching treatments adopted in this study followed the application protocols advised by manufacturers. Evaluation of groups ...
Mechanisms for Low-Light Therapy IX, 2014
Dental bleaching is a frequently requested procedure in clinical dental practice. The literature is contradictory regarding the effects of bleaching agents on both morphology and demineralization of enamel after bleaching. The aim of this study was to analyze by SEM the effect of 35% neutral hydrogen peroxide cured by green LED. Buccal surfaces of 15 pre-molars were sectioned and marked with a central groove to allow experimental and control groups on the same specimen. For SEM, 75 electron micrographs were evaluated by tree observers at 43X, 220X and 1000X. Quantitative analysis for the determination of the surface elemental composition of the samples through X-ray microanalysis by SEM was also performed. The protocol tested neither showed significant changes in mineral composition of the samples nor to dental enamel structure when compared to controls. SEM analysis allowed inferring that there were marked morphological differences between the enamel samples highlighting the need for the use of the same tooth in comparative morphological studies. The tested protocol did not cause morphological damage the enamel surface when compared to their respective controls.
European journal of dentistry, 2011
This clinical study evaluated the effects of a highly concentrated home-bleaching agent on the surface morphology of aesthetically restored teeth. Specimens of human enamel and micro-hybrid composite resin were randomly adhered to the buccal side of right premolar and molar teeth of ten volunteers, who underwent a routine home-bleaching procedure with 16% carbamide peroxide on the upper jaw for 8 days. The mandibular unbleached specimens served as paired controls (n=10). Ultra-structural assessment of the sample was carried out by scanning electron microscopy, and the resulting images were blindly evaluated for topographical alterations. The differences between groups were calculated with the Mann-Whitney test adjusted at the 95% confidence interval. The bleached enamel presented significantly more morphological changes than the control group. The aspect of resin composite exposed to the whitening substance was statistically similar to that observed in the corresponding control grou...
Romanian journal of morphology and embryology = Revue roumaine de morphologie et embryologie, 2009
In this paper we present the results of an experiment with a commercial gel containing carbamide peroxide (CP) 15% (Opalescence 15% PF), aimed to assess the effects of this bleaching agent on the enamel surface of extracted human teeth, by using scanning electron microscopy (SEM). Opalescence 15% PF was applied on two quadrants of twelve extracted permanent, decay-free, human teeth, for 3 hours or 8 hours; for four teeth the application was performed once, while for eight teeth the treatment was repeated daily for 14 days (in order to simulate the usual clinical protocol of at-home bleaching). One quadrant of each tooth was used for control and the remaining quadrant was etched for 40 seconds with a gel containing 37% phosphoric acid. No differences concerning the micromorphology of tooth surface were observed by SEM, on the samples treated with Opalescence 15% PF once, for 3 or 8 hours, when compared to the control. Various, mainly minor changes occurred in samples treated with Opa...
Internal bleaching of teeth: an analysis of 255 teeth
Australian Dental Journal, 2009
Studies about bleaching have not analysed factors that affect the outcome. This aim of this study was to analyse the outcome of, and the factors associated with bleaching. Internal bleaching was done on 255 teeth in 203 patients. Colour was assessed pre-operatively, postoperatively and at recalls. The cause and type of discolouration, number of applications, bleaching outcome, and colour stability were assessed. The most common teeth were upper central (69 per cent) and lateral (20.4 per cent) incisors. Trauma was the most common cause (58.8 per cent), followed by previous dental treatment (23.9 per cent), pulp necrosis (13.7 per cent) and pulp canal calcification (3.6 per cent). Dark yellow and black teeth required more applications of bleach than light yellow and grey teeth. Colour modification was "good" (87.1 per cent) or "acceptable" (12.9 per cent). Teeth restored with glass ionomer cement/composite resin had good colour stability, but this was less predictable with other restorations. No teeth had external invasive resorption. Bleaching endodontically treated teeth was very predictable, especially for grey or light yellow discolourations. Glass ionomer cement/composite restorations were effective at preventing further discolouration. Patient age and tooth type did not affect treatment outcome and no cases of external invasive resorption were observed.
The degree of tooth colour change after using different concentrations of carbamide peroxide
Scripta Medica
Background: Depending on the cause of discoloration, bleaching materials and other factors, vital dental bleaching techniques may be professional (in-office dental bleaching), at-home night-guard bleaching and combined. The main objective of this study was to determine, in vitro, tooth colour change using external dental bleaching techniques with 16% and 30% carbamide peroxide gel and to investigate the effect of concentration of carbamide peroxide gel on the bleaching success. Method: This study included 20 extracted intact human teeth. Teeth were divided into two groups of ten each: the first group was bleached with 16% and the second group with 30% carbamide peroxide gel. The procedure was repeated three times for each tooth. The existing colour on each tooth was recorded using VITA classical shade guide A1-D4 before treatment, after each session and after bleaching was completed. Results: A significant difference (p < 0.01) was found between the first and the second bleaching treatment, for both concentrations (Exact binomial test). A significant difference (p <0.05) was also present between the second and the third treatment, while no statistically significant difference was found between the first and the third bleaching treatment, for both concentrations. There was no statistically significant difference between groups based on degree of tooth shade (χ2 test). Conclusion: The teeth bleaching technique with 16% carbamide peroxide gel and the teeth bleaching technique with 30% carbamide peroxide gel have shown the same efficiency in changing the tooth colour.
An Overview of Extrinsic Tooth Bleaching and its Impact on Oral Restorative Materials
World Journal of Dentistry
Aim: The aim was focused on compiling a comprehensive overview of the extrinsic tooth bleaching and its mechanisms including in vitro and in vivo measurement methods and analyzing factors affecting the efficacy of the bleaching process on restorative materials and tooth structures. Background: The importance of tooth bleaching for patients has notably gained importance and been accompanied by a dramatic increase in the number of relevant products and procedures over the past two decades, with a concomitant rise in publications on this topic. Literatures have put forth that the mechanisms of tooth bleaching by peroxide agents occur by the diffusion of peroxide through the enamel to cause oxidation, and hence, lightening of colored species, particularly, within the dentinal regions. Results: An electronic search was conducted across Ovid Medline, complemented by a manual search across individual databases, such as Cochrane, Web of Science databases, and Google Scholar for the purpose of literature analysis on the mentioned topic. The studies were reviewed and compared. This article summarizes the current scientific and clinical opinions through a brief review with regards to the preferred way of bleaching and its impact on restorative materials. There are controversies in terms of performing tooth bleaching. Regarding extrinsic tooth bleaching, certain literature have pointed out that the in-office method is being followed by a high number of dental practitioners, whereas it should be practiced based on selection of the right cases. Conclusion: Based on previous findings, it is concluded that at-home bleaching technique appears to be the safest technique currently available, which is rapid, easy, and cheap. However, the correct selection of the cases is mandatory. The in-office method provides good outcomes, while it may be insufficient for correcting extreme discoloration. It should be considered that time and concentration are two crucial parameters that have a great influence on the successful bleaching process. These techniques are not entirely free from hazards, and therefore, using these agents under appropriate supervision and consultation with dental professionals is highly essential. Clinical significance: In-office tooth bleaching is a great method for providing rapid tooth bleaching, while it is not as