Tooth Color Change Research Articles

Tooth colour: a review of the literature.

To review current knowledge with respect to tooth colour and its measurement. 'Medline' database for the period 1966 to the present day and 'ISI Web of Science' database for the period 1974 to the present day were searched electronically with key words tooth, teeth, colour and color. The colour and appearance of teeth is a complex phenomenon, with many factors such as lighting conditions, translucency, opacity, light scattering, gloss and the human eye and brain influencing the overall perception of tooth colour. The measurement of tooth colour is possible via a number of methods including visual assessment with shade guides, spectrophotometry, colourimetry and computer analysis of digital images. These methods have successfully been used to measure longitudinal tooth colour changes when the dentition has undergone tooth whitening procedures.

Tooth bleaching--a critical review of the biological aspects.

Present tooth-bleaching techniques are based upon hydrogen peroxide as the active agent. It is applied directly, or produced in a chemical reaction from sodium perborate or carbamide peroxide. More than 90% immediate success has been reported for intracoronal bleaching of non-vital teeth, and in the period of 1-8 years' observation time, from 10 to 40% of the initially successfully treated teeth needed re-treatment. Cervical root resorption is a possible consequence of internal bleaching and is more frequently observed in teeth treated with the thermo-catalytic procedure. When the external tooth-bleaching technique is used, the first subjective change in tooth color may be observed after 2-4 nights of tooth bleaching, and more than 90% satisfactory results have been reported. Tooth sensitivity is a common side-effect of external tooth bleaching observed in 15%-78% of the patients, but clinical studies addressing the risk of other adverse effects are lacking. Direct contact with hydrogen peroxide induced genotoxic effects in bacteria and cultured cells, whereas the effect was reduced or abolished in the presence of metabolizing enzymes. Several tumor-promoting studies, including the hamster cheek pouch model, indicated that hydrogen peroxide might act as a promoter. Multiple exposures of hydrogen peroxide have resulted in localized effects on the gastric mucosa, decreased food consumption, reduced weight gain, and blood chemistry changes in mice and rats. Our risk assessment revealed that a sufficient safety level was not reached in certain clinical situations of external tooth bleaching, such as bleaching one tooth arch with 35% carbamide peroxide, using several applications per day of 22% carbamide peroxide, and bleaching both arches simultaneously with 22% carbamide peroxide. The recommendation is to avoid using concentrations higher than 10% carbamide peroxide when one performs external bleaching. We advocate a selective use of external tooth bleaching based on high ethical standards and professional judgment.

Objective measurement of dental color for age estimation by spectroradiometry

Age-related changes in tooth color have been described previously, however, the use of dental color for age estimation in forensic odontology has been limited due to the difficulty of measuring color objectively. This study presents an objective method for determining dental color to estimate the age of an individual. Dentine color in 250 teeth from patients ranging in age from 10 to 89 years was determined by spectroradiometry. Color measurements were performed as suggested in the CIE 1931 (International Commission on Illumination). Chromaticity coordinates ( x, y, z), luminance ( Y), whiteness index (WIC, Z%, WIC) and yellowness index (YI) were obtained. Correlations between these colorimetric variables and aging were established by linear regression analyses. All the variables fit the mathematical model with correlation coefficients ranging from 0.53 to 0.75. This method of color measurement produced an expected associated error of calibration averaging 13.7 years about the mean estimated values, at a 70% level of confidence. Two different multiple regression models for dental age estimation were tested, and variables that made the greatest contributions to age calculation were identified. To determine the effect of postmortem interval on tooth color and its influence in age estimation, 37 teeth obtained from human skeletal remains buried during an interval ranging from 21 to 37 years were also studied. In this material, the correlation between age and dental color measured by spectroradiometry was weaker than in fresh extracted teeth. It is concluded that determination of dentine color by spectroradiometry is a potentially useful objective method to estimate age in forensic studies in combination with other methods.

The Effect of a 10% Carbamide Peroxide Home Bleaching System on the Gingival Health

Esthetics plays an important role in dentistry today. Because of an increased emphasis on beauty and health, cosmetic dentistry has been the thrust to the forefront of many practices. Many health products are used for bleaching teeth, but all side effects are not known. Tooth sensitivity and gingival irritation are the most common side effects, but they are typically mild and transient in nature. The aim of this investigation was to evaluate objectively the effect of 10% carbamide peroxide gel (Opalescence Utradent Inc, USA) on gingival health by measuring changes in Bleeding Index, Plaque Index, and Gingival Index. Eighteen subjects, 11 female and 7 male, age range 15-30 years (mean 24 years), were selected for the study as a convenient sample. Their teeth had either fluorosis, dental stains, smoking, or tetracycline staining. The Opalescence system was used as office monitored, at-home bleaching for three weeks. There was a statistically significant reduction in bleeding on probing (1% - 37%, p < or = 0.003), Plaque Index (4% - 50%, p < or = 0.000), and Gingival Index (2.5% - 34%, p < or = 0.002). Only two subjects reported tooth hypersensitivity, and none of the subjects complained about gingival irritation. There was a positive change in tooth color as far as staining was concerned. Further research including randomized controlled, double blind clinical trials is needed to confirm these findings and to examine other factors related to bleaching of teeth.

The effects of polishing and bleaching on the colour of discoloured teeth in vivo

Bleaching is an effective method for restoring the colour of discoloured vital teeth. Power bleaching, in particular, in which a bleaching solution containing 35% hydrogen peroxide is activated by a strong light source using a plasma arc, makes it possible to bleach teeth effectively in a short time. The purpose of this study was to determine how polishing or power bleaching the tooth surface affects tooth colour. The subjects selected were patients who had slightly discoloured teeth. The colour of precisely identified sites on six anterior teeth was measured before treatment, after polishing and after bleaching, to ascertain changes in colour. The measurements revealed that tooth colour changes slightly after polishing, but it shows a much greater change after bleaching, and that the post‐bleaching change in tooth colour was caused both by elevation of lightness and reduction of yellowness. They also revealed that the colour difference between pre‐treatment and post‐bleaching does not depend on the type of tooth. These results suggested that power bleaching is an effective technique for improving slightly discoloured vital teeth, regardless of the type of tooth.

The effects of polishing and bleaching on the colour of discoloured teeth in vivo.

Bleaching is an effective method for restoring the colour of discoloured vital teeth. Power bleaching, in particular, in which a bleaching solution containing 35% hydrogen peroxide is activated by a strong light source using a plasma arc, makes it possible to bleach teeth effectively in a short time. The purpose of this study was to determine how polishing or power bleaching the tooth surface affects tooth colour. The subjects selected were patients who had slightly discoloured teeth. The colour of precisely identified sites on six anterior teeth was measured before treatment, after polishing and after bleaching, to ascertain changes in colour. The measurements revealed that tooth colour changes slightly after polishing, but it shows a much greater change after bleaching, and that the post-bleaching change in tooth colour was caused both by elevation of lightness and reduction of yellowness. They also revealed that the colour difference between pre-treatment and post-bleaching does not depend on the type of tooth. These results suggested that power bleaching is an effective technique for improving slightly discoloured vital teeth, regardless of the type of tooth.

Precision of in vivo colorimetric assessments of teeth

Purpose. The repeatability of an intraoral positioning device for a tristimulus photoelectric colorimeter was assessed with the left maxillary central incisors of seven subjects. Material and Methods. Intraclass correlation coefficients and repeatability color differences were determined from repeated color measurements made by the same examiner on 3 separate days. Interexaminer repeatability was tested by comparing CIELAB measurements of the same tooth made by two different examiner combinations, both using the positioning device. Results. High intraclass correlation coefficients were demonstrated for intraexaminer and interexaminer repeatability. Repeatability color differences were 0.34 ▵E units for intraexaminer assessments, whereas interexaminer repeatability color differences were 0.13 and 0.61 ▵E units for the two examiner pairs. Conclusion. It was concluded that a colorimeter, equipped with a custom positioning jig, had acceptable precision for intraoral measurement of longitudinal changes in tooth color. (J Prosthet Dent 1997;77:464-70.)

Assessing Tooth Color Change After Repeated Bleaching: In Vitro with a 10 Percent Carbamide Peroxide Gel

The aim of this study was to obtain information about tooth color changes in 25 extracted human incisors resulting from repeated bleaching with a 10 percent carbamide peroxide gel. Using a colorimeter, the author recorded color changes in the L*a*b* color space after each bleaching period. The observed tooth color change was found to be dependent on the bleaching time, the specific bleached section and the initial color. The most significant total tooth color change was observed in the incisal section of the crown, followed by the middle and the cervical sections.

Evaluating Tooth Color Change from Carbamide Peroxide Gel

A double-blind experiment assessed the efficacy, longevity and safety of a tooth whitener in young adults. Significant color changes occurred after active treatment but were substantially reversed after one week. No permanent changes were found in either pulpal or gingival health.

Comparison of Enamel Microabrasion Techniques: Prema Compound versus a 12‐Fluted Finishing Bur

This clinical study was done to compare the effectiveness of microabrasion with Prema Compound versus a high speed 12-fluted bur with water spray in removing incisor hypomineralized defects. Twenty-one patients had two incisors with enamel surface defects. It was randomly decided to use Prema Compound on one of the incisors and a 12-fluted bur on the contralateral incisor. One operator did all the procedures, but the tooth's color changes were rated by three observers who rated color photographs pre- and postoperatively, and one of the three rated each patient's teeth in person. The data revealed that there was no significant difference between Prema Compound and the 12-fluted bur in removing incisor hypomineralized defects. Both microabrasion techniques significantly improved the tooth's color, but the Prema method took over 9 minutes longer. The 12-fluted bur caused no clinically identifiable marks on the enamel surface. Both techniques were very reliable in removing the brown hypomineralized enamel defects, but were far less reliable in removing the white mineralization defects. The 12-fluted bur appeared to be an easier and equally effective alternative to Prema Compound for mineralization defects in incisors.

Duration of Tooth Color Change After Bleaching

Tooth color change was monitored after a single, in-office bleaching technique using a colorimeter. Twenty young adults participated in the double-blind study at The Ohio State University College of Dentistry. Half of the participants had their maxillary anterior teeth bleached and half were controls. By one month, the large initial color change was considerably reversed and only noticed by one subject. After six months, the effect of bleaching was small, but still measurable.