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PubMed1992

Application of the environmental SEM in human dentin bleached with hydrogen peroxide in vitro.

The environmental SEM (E-SEM) can be used unfixed biological samples under a low vacuum and wet condition. In this study, the fractured dentin of unfixed human teeth was treated with a 30% hydrogen peroxide solution (H2O2) for the examination of tooth-bleaching prior to the E-SEM and a conventional SEM. The peritubular matrix (PM) always showed a few cracks along the long axis of a dentinal tubule, and the ends of fine fibrils rose to the smoothly changed surface of the intertubular matrix (IM). The E-SEM with non-fixation and the conventional SEM following fixation indicated that the hydrogen peroxide solution easily permeated the PM and dissolved the non-fibrillar substance including the cracks of the PM by the constriction. In the IM, the solution may partially dissolve the organic parts within mineralized fibrils as well as non-fibrillar substance between the fibrils, although these remnants might precipitate again there.

Adolescent↗
PubMed1999

The eleventh hour or where are our orthodontic limits? Case report.

It is illustrated in a patient with periodontal attachment loss up to the apical root third that a combined periodontal/orthodontic approach may be beneficial even in seemingly hopeless cases. The problems of orthodontic limits and the positive effects of guided tissue regeneration are discussed.

Combined Modality Therapy↗
PubMed2006

Effects of hydrogen peroxide (H2O2) on alkaline phosphatase activity and matrix mineralization of odontoblast and osteoblast cell lines.

Hydrogen peroxide (H(2)O(2)), an oxidizing agent, has been widely used as a disinfectant. Recently, because of its reactive properties, H(2)O(2) has also been used as a tooth bleaching agent in dental care. This is a cause for concern because of adverse biological effects on the soft and hard tissues of the oral environment. To investigate the influence of H(2)O(2) on odontoblasts, the cells producing dentin in the pulp, we assessed cellular viability, generation of reactive oxygen species (ROS), alkaline phosphatase (ALP) activity, and nodule formation of an odontoblastic cell line (MDPC-23) after treatment with H(2)O(2), and compared those with the effects on preosteoblastic MC3T3-E1 cells. Cytotoxic effects of H(2)O(2) began to appear at 0.3 mmol/L in both MDPC-23 and MC3T3-E1 cells. At that concentration, the accumulation of intracellular ROS was confirmed by a fluorescent probe, DCFH-DA. Although more ROS were detected in MDPC-23, the increasing pattern and rate are similar between the two cells. When the cells were treated with H(2)O(2) at concentrations below 0.3 mmol/L, MDPC-23 displayed a significant increase in ALP activity and mineralized bone matrix, while MC3T3-E1 cells showed adverse effects of H(2)O(2). It is known that ROS are generally harmful by-products of aerobic life and represent the primary cause of aging and numerous diseases. These data, however, suggest that ROS can induce in vitro cell differentiation, and that they play a more complex role in cell physiology than simply causing oxidative damage.

Alkaline Phosphatase↗
PubMed1996

Demineralization effects of 10 percent carbamide peroxide.

OBJECTIVES: The purpose of this in vitro study was to measure the amount of calcium lost from enamel exposed to a 10% carbamide peroxide solution. METHODS: Nine teeth (3 incisors, 2 premolars, 4 molars) were sectioned to serve as paired test and control specimens. Each tooth half was coated with wax, leaving a uniform 3 mm x 4 mm window of exposed enamel. Test specimens were placed in culture tubes with 1.00 ml of deionized water and 0.02 ml of 10% carbamide peroxide for 6 h; controls were exposed to water alone. Calcium concentrations in the solutions were measured using a Perkin-Elmer 5100 atomic absorption spectrophotometer. RESULTS: Teeth exposed to carbamide peroxide lost an average of 1.06 micrograms/mm2 of calcium. This amount of loss was significantly greater than controls (p < 0.001), according to ANOVA. For comparison, teeth were exposed to a cola beverage for 2.5 min, the time equivalent of drinking a 16 oz. beverage. The amount of calcium lost from these teeth was also about 1 microgram/mm2. CONCLUSIONS: Teeth exposed to 10% carbamide peroxide lost calcium. However, the amount of loss was small, and may not be clinically significant.

Analysis of Variance↗
PubMed1987

A conservative postorthodontic treatment of enamel stains.

The purpose of this presentation is to describe a method used to remove or improve superficial stains in the enamel including mild decalcification present before and after orthodontic therapy. This procedure is only successful in the treatment of stains involving the outer enamel surface and is not effective for treating generalized pigmentation of the enamel and/or dentin. A step-by-step approach for the removal of the superficial enamel stains is presented.

Color↗
PubMed2004

In vitro evaluation of a novel 6% hydrogen peroxide tooth whitening product.

OBJECTIVES: The aims of this study were to evaluate the in vitro tooth whitening effects of a novel 6% hydrogen peroxide containing tooth whitener Xtra White (XW) on extrinsic stain and intrinsic tooth colour and the effects on enamel and dentine microhardness. In addition, to determine the levels of peroxide found in tooth pulp chambers after treatment with XW in vitro. METHODS: Extrinsic stain changes were determined by measuring colour changes of tea stained hydroxyapatite discs after treatment with water, placebo gel, XW or Colgate Simply White (CSW). Intrinsic tooth colour changes were determined by treating extracted human teeth in vitro with a placebo gel, XW or CSW for a simulated two weeks use and measuring colour differences with a chroma meter. Teeth treated with placebo gel and XW were cross-sectioned and the subsurface enamel and dentine was polished and the microhardness determined. The peroxide concentration found in extracted tooth pulp chambers was determined spectrophotometrically. RESULTS: XW gave significantly more extrinsic stain removal (p<0.0001) and an increase in tooth whiteness (p<0.05) than a placebo gel, but was not significantly different to CSW. There were no significant differences in subsurface enamel and dentine microhardness values for the placebo and XW treated teeth. The mean concentration of peroxide found in the tooth pulp chambers was 0.44 mM, which is over 3000 times below the concentration reported to cause pulpal enzyme damage. CONCLUSIONS: XW has been shown to be an effective tooth whitening product in vitro with support for its safety on subsurface enamel and dentine together with its safety on tooth pulp tissue.

Color↗
PubMed2004

Clinical evaluation of a novel whitening gel, containing 6% hydrogen peroxide and a standard fluoride toothpaste.

OBJECTIVES: The aim of this study was to determine the effect on tooth colour (after 1 and 2 weeks use) of a self-applied tooth-whitening gel containing 6% hydrogen peroxide using a novel applicator, compared to a standard fluoride toothpaste. METHODS: A 2-week, examiner-blind, stratified, parallel design clinical trial was conducted. Efficacy was measured by comparing the Vita shade scores recorded at baseline and after 1 and 2 weeks of product application. To qualify for the study, subjects were required to have at least one upper incisor/canine tooth measuring Vita shade A3 or darker. All upper incisors/canines of qualifying subjects were evaluated for change in Vita shade irrespective of their level of whiteness at baseline, allowing for the whitening gel to be tested on the full range of Vita tooth shades. One hundred and seventeen subjects were divided into two groups, balanced according to their darkest tooth shade. One group followed a 2-week, twice-daily regimen of brushing with toothpaste followed by the application of the hydrogen peroxide whitening gel. The other group brushed twice daily with toothpaste for 2 weeks. RESULTS: Subjects using the whitening gel showed a statistically significant improvement, (p<0.05) in mean tooth shade score of 0.75 and 1.02 units after 1 and 2 weeks, compared to baseline. These improvements from baseline were significantly greater than those observed for the toothpaste only group (0.14 and 0.35 units change after 1 and 2 weeks). CONCLUSIONS: The self-applied tooth-whitening gel containing 6% hydrogen peroxide has been shown to significantly improve the whiteness of teeth after 1 and 2 weeks of product use, compared to the baseline and the toothpaste only group.

Adolescent↗
PubMed2004

Clinical evaluation of the stain removing ability of a whitening dentifrice and stain controlling system.

OBJECTIVES: This study aimed to evaluate the stain removing/controlling properties of a whitening dentifrice and a stain controlling system, in a parallel group, multiple use study. METHODS: Subjects (63), were stratified according to baseline stain scores and randomly allocated to a group, A (standard dentifrice), B (whitening/stain removing dentifrice) or C (whitening/stain removing dentifrice, tooth polish, tooth polisher and whitening/stain removing mouthwash). At each attendance, extrinsic stain was scored blind by a trained and calibrated examiner using the Shaw and Murray Stain Index, under constant lighting conditions. In addition, whiteness was measured using a colorimeter. RESULTS: The toothpaste regimens were well balanced at baseline (p=0.811). At 4 weeks, Regimens B and C had significantly less stain than A (p<0.05). Lower stain values were maintained/reduced for regimens B and C by week 6, with changes from baseline significantly greater than for Regimen A. When lightness was assessed by colorimeter, Regimen C was also found to be significantly whiter than Regimen A (p<0.05). CONCLUSIONS: It was concluded that both whitening regimens had a significant effect on reducing tooth staining and improving whiteness over the 6 week time period.

Adult↗
PubMed2005

Comparison of quantitative light-induced fluorescence (QLF) and digital imaging applied for the detection and quantification of staining and stain removal on teeth.

OBJECTIVES: This study compares the use of QLF with digital imaging in the detection and quantification of the development and removal of stain on teeth. METHODS: Two experimental phases, tooth staining and tooth whitening, conducted in vitro on labial 12 mm(2) enamel windows made on ten extracted bovine teeth, developed stains in 6-min cycles (2 min in each solution) using artificial saliva, chlorhexidine and tea solutions and removed them using sodium perborate monohydrate in 2-min cycle monitored at the end of each cycle with QLF (Inspektor Research Systems, NL) and digital photography (Fuji, Japan). The stain values were quantified as DeltaQ derived from QLF and DeltaE from digital imaging. This was observed by the two methods correlated with Pearson correlation coefficient (r). Regression equations (R(2)) were also obtained. RESULTS: For both staining and stain removal there was a statistically significant (p<0.01) reverse correlation between DeltaQ values for QLF (r=-0.924, R(2)=85.4%) and DeltaE values for digital imaging (r=-0.994, R(2)=98.8%), respectively. CONCLUSION: QLF showed a high correlation with digital imaging as a technique for detecting and monitoring tooth stains and tooth whitening in vitro. The potential for QLF with further development as a tool for monitoring staining and whitening of teeth may be possible in vivo in addition to the diagnostic ability for caries detection.

Animals↗
PubMed2000

The chemical stain removal properties of 'whitening' toothpaste products: studies in vitro.

BACKGROUND: A considerable number of toothpastes are available as tooth whitening products. Most appear to contain ingredients that might remove extrinsic stains rather than change natural tooth colour. Extrinsic stain removal could be achieved by physical or chemical means. AIM: The purpose of this study was to measure the chemical stain removal properties of a range of whitening toothpaste products and experimental formulations using a standardised method in vitro. MATERIALS AND METHOD: 5 separate studies were conducted involving a total of 39 agents of which 28 were whitening products, 7 were experimental formulations, 2 were oxidising mouthrinses used as positive controls, 1 was a popular fluoride toothpaste product as a benchmark control, and 1 was water as the negative control. The formulations and controls varied in each study. The stain model was saliva/chlorhexidine/tea stain developed on optically clear acrylic to an optical density of at least 2.0. Groups of stained specimens were exposed to standard slurries or solutions of each test agent for 1 minute periods up to 5 minutes. Optical density readings were taken at each 1 minute time point. Analyses were based on per cent stain remaining after 5 minutes and time to 75% stain remaining. RESULTS: 3 toothpaste products achieved 100% stain removal by 5 minutes; 2 of these in 3 out of 4 studies in which they were used. 4 experimental formulations also achieved 100% stain removal. In general agents with high total stain removal also had short times to 75% stain remaining. The majority of agents tested had low total chemical stain removal and prolonged times to 75% stain remaining. A few agents were little different from water and several similar in effect to the conventional fluoride toothpaste. This method in vitro tests agents under the best case scenario conditions for chemical stain removal. CONCLUSION: Only a small number of the whitening toothpaste products have good chemical stain removal potential; the majority are unlikely to achieve their claimed benefits through chemical stain removal. There is clearly a need for further data on the actual effects of such products using both methods in vitro and particularly in vivo or in situ.

Acrylic Resins↗
PubMed2001

The use of QLF to quantify in vitro whitening in a product testing model.

BACKGROUND: Professional and consumer interest in whitening products continues to increase against a background of both increased oral health awareness and demand for cosmetic procedures. In the current legal climate, few dentists are providing 'in-office' whitening treatments, and thus many patients turn to home-use products. The most common of these are the whitening toothpastes. Researchers are keen to quantify the effectiveness of such products through clinically relevant trials. AIM: Previous studies examining whitening products have employed a variety of stained substrates to monitor stain removal. This study aimed to quantify the removal of stain from human enamel using a new device, quantitative light-induced fluorescence (QLF). The experimental design follows that of a product-testing model. MATERIALS AND METHODS: A total of 11 previously extracted molar teeth were coated with transparent nail varnish leaving an exposed window of enamel. The sound, exposed enamel was subject to a staining regime of human saliva, chlorhexidine and tea. Each of the eleven teeth was subjected to serial exposures of a positive control (Bocasan), a negative control (water) and a test product (Yotuel toothpaste). Following each two-minute exposure QLF images of the teeth were taken (a total of 5 applications). Following completion of one test solution, the teeth were cleaned, re-stained and the procedure repeated with the next solution. QLF images were stored on a PC and analysed by a blinded single examiner. The deltaQ value at 5% threshold was reported. ANOVA and paired t-tests were used to analyse the data. RESULTS: The study confirmed the ability of QLF to longitudinally quantify stain reduction from human enamel. The reliability of the technique in relation to positive and negative test controls was proven. The positive control had a significantly (alpha = 0.05) higher stain removal efficacy than water (p = 0.023) and Yotuel (p = 0.046). Yotuel was more effective than water (p = 0.023). CONCLUSION: The research community, the practicing clinician and the consumer all require sound product evaluation data. The use of human enamel specimens may offer more relevant clinical data. QLF has been designed as an in vivo device. Further development of the technique should permit in vivo clinical whitening trials.

Analysis of Variance↗