Rilevamento del colore e classificazione delle discromie dentali

Objectives

To consider methods for assessing tooth color and to describe the classification of dental discolorations.

Materials and methods

The author describes the color characteristics of dental tissues and the methods of color evaluation (subjective or objective by means of a spectrophotometer). The intrinsic and extrinsic tooth discolorations and their etiologies are examined.

Results and conclusions

Intrinsic discolorations may be pre-eruttive, if formed during the development of tissues that make up the tooth, or post-eruptive, if formed after the eruption of teeth. The extrinsic discolorations or pigments are the most common and thus are the reasons where patient asks for a bleaching treatment more frequently. In fact, they cannot be discolored, but cleaned. They are most easily removed with professional procedures and with a good compliance of the patient at home.     

Chemical plaque control and extrinsic tooth discoloration

Abstract The etiology of extrinsic tooth discolorations due to chemical, plaque-preventive agents is not fully understood. However, information from experimental investigations point to at least 3 possible mechanisms. (A) Non-enzymatic browning reactions (Maillard reactions). (B) Formation of pigmented metal (Fe, Sn)-sulfides. (C) Reaction products of food and beverage constituents and chemical, plaque-preventive compounds. Available evidence indicates that browning (A) and formation of pigmented metal sulfides (B) are the most likely causes of these discolorations while dietary factors (C) may play a modifying role.     

Characterization of saliva proteins from 'stainers' and 'non-stainers' adsorbed to hydroxyapatite

Stainers and non-stainers were selected on the basis of their individual tendency to develop extrinsic tooth discolorations from a chlorhexidine mouth rinse. Saliva proteins adsorbed to hydroxyapatite in vitro and in vivo pellicle from the participants were analyzed by gel filtration and ion-exchange chromatography. Two distinct anionic components were isolated. The elution patterns from stainers and non-stainers were identical. Amino acid analyses of the main peaks demonstrated a prevalence of serine, glycine, and glutamic acid.     

Auger electron spectroscopy of iron in dental pellicle from stainers and non-stainers

Stainers and non-stainers were selected on the basis of their individual tendency to develop extrinsic tooth discolorations from a chlorhexidine mouth rinse. Pellicle was allowed to form in vivo on dental enamel slabs in both stainers and non-stainers. The slabs were then exposed to chlorhexidine 0.2% and a neutral iron salt solution extraorally either once or until a brownish discoloration appeared from the stainers. The pellicle was examined for its content and distribution of iron by Auger electron spectroscopy (AES). Pellicle from stainers showed higher concentrations of iron than pellicle from non-stainers.     

Evaluation of extrinsic tooth discoloration.

Extrinsic brown tooth discolorations are frequently detected in connection with antibacterial agents used for chemical plaque control. The present investigation confirmed the staining ability of an antibacterial quarternary ammonium salt, benzethoniumchloride, used as a 2% additive to a dentifrice. A weak chelator did not alter the discoloration tendency. Extrinsic discoloration was evaluated both by direct inspection, from color photographs and by using a microphotometric technique. The discoloration tendency was well demonstrated by all three techniques. Evaluation from the color photographs, however, may be preferable in epidemiological surveys while the microphotometric technique may possess certain advantages in detailed experimental discoloration studies.     

Dental Discoloration: An Overview

Abstract: Often the first evidence of variation from normal in human dentition is an observable difference in the color of the teeth. During the past decade, the demand for conservative esthetic dentistry has grown dramatically. Tooth discoloration is a frequent dental finding, associated with clinical and esthetic problems. It differs in etiology, appearance, composition, location, severity, and firmness in adherence to the tooth surface. Basically, there are two types of tooth discolorations: those caused by extrinsic factors and those caused by intrinsic congenital or systemic influence. The intensity of stains may be worsened if there are enamel defects. Tooth discoloration presents two major challenges to the dental team. The first challenge is to ascertain the cause of the stain; the second is its management.     

Tooth whitening today

BACKGROUND: Methods to improve the esthetics of the dentition by tooth whitening are of interest to dentists, their patients and the public. In the past 20 years, research on bleaching and other methods of removing tooth discolorations has dramatically increased. Dentist-supervised and over-the-counter products now are available to solve a variety of tooth discoloration problems without restorative intervention. The indications for appropriate use of tooth-whitening methods and products are dependent on correct diagnosis of the discoloration. OVERVIEW: Tooth-whitening methods include the use of peroxide bleaching agents to remove internal discolorations or abrasive products to remove external stains. Peroxide bleaching procedures are completed by the dentist in single or multiple appointments, or by the patient over a period of weeks to months using custom trays loaded with a bleaching agent. Both methods are safe and effective when supervised by the dentist. Microabrasion is indicated for the removal of isolated discolorations that often are associated with fluorosis. Whitening toothpastes remove surface stains only through the polishing effect of the abrasives they contain. CONCLUSIONS AND PRACTICE IMPLICATIONS: Tooth whitening is a form of dental treatment and should be completed as part of a comprehensive treatment plan developed by a dentist after an oral examination. When used appropriately, tooth-whitening methods are safe and effective.     

The etch-bleach-seal technique for managing stained enamel defects in young permanent incisors

Hypomineralized enamel defects frequently are manifest as a mottled-white appearance and can be associated with variable degrees of discrete yellow-brown intrinsic staining. Numerous treatment approaches have been proposed, ranging from bleaching to enamel reduction to restorative techniques. Bleaching of hypomineralized enamel lesions, using 1 to 2 applications (10 to 15 minutes each) of 5% sodium hypochlorite, has been applied clinically. Treatment using this approach has proven successful in removing yellow-brown discolorations from lesions in young permanent teeth. Young permanent incisors with yellow-brown intrinsic discolorations can often be treated by a simple and conservative bleaching protocol using sodium hypochlorite.     

Disturbances in oral and dental structures in patients with pediatric lymphoma after chemotherapy: a preliminary report

OBJECTIVE: The purpose of this study was to evaluate the effects of chemotherapy on oral and dental structures and craniofacial growth in 30 survivors of childhood lymphoma. STUDY DESIGN: Eruption status, root malformations, premature apexification, agenesis, crown anomalies, soft tissue abnormalities, gingival and periodontal status, enamel defects and discolorations, and craniofacial growth status of the subjects were documented and compared with findings in 20 healthy children who served as controls. RESULTS: Statistically significant (P < .05) differences between the study and control groups were found for plaque index, enamel hypoplasias, discolorations, and agenesis. CONCLUSIONS: The results of the study suggest that antineoplastic therapy and/or childhood cancer can result in a higher prevalence of various malformations in teeth. Children treated in the early years of their lives displayed the most severe dental defects, suggesting that immature teeth are at a greater risk of developmental disturbances than fully developed teeth.     

Correlation between clinical scoring of secondary caries at crown margins and histologically assessed extent of the lesions

PURPOSE: The aim of this study was to propose a new clinical diagnostic rating index for secondary caries lesions at crown margins and to correlate this index with histologic evaluations. MATERIALS AND METHODS: Based on criteria for the evaluation of root caries, a modification of secondary caries lesions at the crown margin (SC index) was applied; the lesion characteristics were described as SCO to SC4. A total of 16 crowned teeth exhibiting secondary caries were randomly selected. The teeth were rated and grouped according to their clinical SC grades (SC1 to SC4). After embedding in Technovit, the teeth were serially sectioned and histologic caries scores were given for each section. RESULTS: Fifty-two percent of the prepared margins were in cementum/dentin. Crown margins with no caries lesions were mainly found in teeth clinically rated as SC1 and exhibiting localized discolorations, whereas deep lesions were found histologically at teeth rated SC4. The nonparametric test according to Spearman's rank correlation coefficient (rho) confirmed a highly significant correlation between the clinical SC index and the histologic evaluation (rho = 0.87, 95% confidence interval = 0.67 to 0.96, P < 0.01). SC1 discolorations overestimate caries lesions, whereas SC2 and SC4 lesions are well correlated to the percentage of histologically evaluated caries extension into all sections of a tooth. Lesions rated SC3 demonstrated a high variability of caries penetration into the dentin. CONCLUSION: The depth of discolorations and circular lesions is clinically not well predictable. Clinical diagnosis for localized superficial caries and deep caries lesions at the crown margin correlated well with the histologic caries rating.     

Corrosion Susceptibility of Lingual Wire Extensions in Removable Appliances An in Vitro Study

MATERIAL AND METHODS: The corrosion resistance of ten different round orthodontic wires as plastic-encased extensions was evaluated in vitro. Following the production of defined test samples with free as well as with acrylic-embedded wire segments, ten samples of each product were subjected to gap provocation by deflecting the free-running wire ends with an electric drive, while 10 samples remained provocation-free. The tests were run under standardized conditions (7 days, 37 degrees C, pH 2.3, 0.1 mol NaCl/CH3CHOHCOOH), and the findings were analyzed by stereo light microscopy and scanning electron microscopy. RESULTS: The following alterations were observed on the wire surfaces: a) crevice corrosion with substantial linear surface erosion and opaque discolorations, b) localized pitting corrosion, and c) mild surface erosion with translucent discolorations. The reactions of the test samples were similar in both those that were subjected to addition mechanical loading in the electrolyte and those that were not. Cr-Ni steels were susceptible to corrosion, whereas Co-Cr alloys as well as low-nickel manganese steels had only slight visible alterations, if any, in the embedded wire sections. CONCLUSIONS: Clinically occurring discolorations in the acrylic can be attributed to corrosion processes on the embedded wire extensions. These processes can be simulated and observed in vitro. During the processing of acrylic materials now customary in the orthodontic laboratory, crevices are inevitably formed between the wire and the acrylic, furthering the corrosion process. Our results suggest that, being more resistant to crevice corrosion, Co-Cr alloys or low-nickel steels can be considered as alternatives.     

Extrinsic tooth discolouration in 11-16 year-old Nigerian children.

This study was done to ascertain the prevalence and aetiology of extrinsic stains among 11-16 year-old school children in Surulere, which is one of the Local Government Areas (LGAs) in Lagos, Nigeria. 600 school children were randomly selected from 6 schools, 3 primary and 3 secondary, in the LGA. About 100 children were examined from each age category of 11 to 16 years for extrinsic stains, and information on their dietary and oral habits was obtained. A 64.0% prevalence of extrinsic stains was found among the study population (boys =64.5%, girls = 63.4%). The colour of the extrinsic stains ranged from yellow, brown, green, orange, black to red and were mainly due to poor oral hygiene. The extrinsic stains were derived mainly from food consumption and the action of chromogenic bacteria. The high level of extrinsic stains seen in this study is also a reflection of the low utilisation of dental services and subsequently of professional oral prophylaxis among the subjects as 91.5% had never visited a dentist and 94.8% had never had a professional oral prophylaxis. The prevalence of stains seen in the study population is higher than would be expected in adolescents who should be rather self-conscious at that age, the older adolescents even having a significantly higher prevalence of stains than younger adolescents (p < 0.05). No statistical difference in extrinsic stains prevalence was found among the sexes (p = 0.7) or among social classes (p> 0.05). The establishment of a school oral health care programme in the Local Government Area is advocated, as this may be the only source of oral care for these children. Dental health education and promotion services should be the main thrust of such services, which may be in form of fixed or mobile dental clinics.     

Dental discolorations and side effects with iron and placebo tablets.

In a randomized double-blind cross-over study, 19 young women received iron tablets (Neo-Fer) containing 0.20 g ferrous fumarate (60 mg Fe++), and placebo tablets, twice daily during two periods of 8 weeks each. Development of discolorations on fillings and tooth surfaces was studied by careful clinical examination, and by paired comparison of color transparencies taken before and after each period of treatment. Any tendency of this oral iron preparation to cause dental discolorations could not be detected in the present group of women with good oral hygiene. Seven participants reported gastrointestinal discomfort, two of them only when receiving placebo tablets.     

The effect of an alexidine mouthwash on dental plaque and gingivitis.

The alexidine mouthrinse used in this study (CP-101) is effective in reducing plaque. There was a reduction in gingivitis after 6-months use but not at a statistically significant level. An extrinsic brown stain occurred at a significant level on the teeth of participants using the active mouthrinse. Blood and urine laboratory results indicated that alexidine can be safely used over a 6-month period.     

Migration of metallic ions from screwposts into dentin and surrounding tissues.

Previous investigations have shown htat corrosion and other electrochemical processes occure when different alloys or metals are found together in the same mouth. In the present report, when teeth were restored using non-noble metallic posts, the metals diffused out to surrounding hard and soft connective tissues. The material consisted of extracted teeth with screw posts and surrounding discolored connective tissues. The screwposts had been cemented to the teeth 3--10 years earlier. The distribution of metal ions was determined by means of energy-dispersive X-ray microanalysis. Copper and zinc were found in both hard and soft tissues. Relatively high concentrations of copper ions were identified in areas of the teeth with blue-green discolorations. Zinc ions were detected in the dentin; they most probably originated from the screwposts and the cement, but zinc is also found in normal human dentin. Copper, zinc, silver and iron were found in the dark discolorations of the gingiva adjacent to the extracted teeth.     

Migration of metallic ions from screwposts into dentin and surrounding tissues

ABSTRACT – Previous investigations have shown that corrosion and other electrochemical processes occur when different alloys or metals are found together in the same mouth. In the present report, when teeth were restored using non-noble metallic posts, the metals diffused out to surrounding hard and soft connective tissues. The material consisted of extracted teeth with screwposts and surrounding discolored connective tissues. The screwposts had been cemented to the teeth 3–10 years earlier. The distribution of metal ions was determined by means of energy-dispersive X-ray microanalysis. Copper and zinc were found in both hard and soft tissues. Relatively high concentrations of copper ions were identified in areas of the teeth with blue-green discolorations. Zinc ions were detected in the dentin; they most probably originated from the screwposts and the cement, but zinc is also found in normal human dendn. Copper, zinc, silver and iron were found in the dark discolorations of the gingiva adjacent to the extracted teeth.     

Dental and Oral Discolorations Associated with Minocycline and Other Tetracycline Analogs

Abstract: It has been well acknowledged in recent literature that minocycline, a semisynthetic tetracycline derivative, causes discolorations in adult teeth and various other collagenous tissues. This article presents the most common patterns of minocycline staining in addition to comparing the staining patterns of other tetracycline analogs in the permanent dentition. It also reviews the literature's most prominent theories describing the process of minocycline discoloration, and evaluates their plausibility. It is a goal of this article to make dental practitioners aware of the possible effects of minocycline therapy and to highlight useful ways to treat or prevent these discolorations. Currently, conventional treatments include vital and nonvital bleaching, veneers, or crowns, depending on the severity of the discoloration. The literature shows that possible preventive efforts revolve around cessation of the drug or the use of large doses of vitamin C or other antioxidants in conjunction with minocycline therapy to prevent the formation of the pigment responsible for the staining.     

Exposure parameters in sens-a-ray direct digital radiography and their effects on diagnostic accuracy of carious lesions

We studied the effects of tube potentials and exposures on the accuracy of carious diagnosis using Sens-A-Ray direct digital radiography with two types of CCD detectors, one without and one with a scintillator layer. Our second objective was to determine the optimum exposure factors. Radiographs of 75 extracted premolars with and without clinically observed discolorations or cavities were obtained at exposure settings of 70 kVp and 90 kVp. The observers diagnosed dental caries in radiographs exposed with the two types of detectors. The results were analyzed with Receiver Operating Curve (ROC) technique. The averaged areas under the ROC curves were plotted as functions of exposure to obtain Diagnostic Accuracy (DA) curves. No statistically significant difference was found in diagnostic accuracy for the two tube potentials. However, there was a statistically significant difference in diagnostic accuracy for the two lesion types, discolorations and cavities. There was also a significant effect on diagnostic accuracy related to exposure: the exposure providing the optimum diagnostic accuracy corresponds to a gray level of about 31 when SVGA graphics are employed, i.e., in the middle of the available range. To acquire optimum radiographs for diagnosing carious lesions with the Sens-A-Ray system, the operator must select the appropriate exposure parameters.     

Dental and oral discolorations associated with minocycline and other tetracycline analogs.

It has been well acknowledged in recent literature that minocycline, a semisynthetic tetracycline derivative, causes discolorations in adult teeth and various other collagenous tissues. This article presents the most common patterns of minocycline staining in addition to comparing the staining patterns of other tetracycline analogs in the permanent dentition. It also reviews the literature's most prominent theories describing the process of minocycline discoloration, and evaluates their plausibility. It is a goal of this article to make dental practitioners aware of the possible effects of minocycline therapy and to highlight useful ways to treat or prevent these discolorations. Currently, conventional treatments include vital and nonvital bleaching, veneers, or crowns, depending on the severity of the discoloration. The literature shows that possible preventive efforts revolve around cessation of the drug or the use of large doses of vitamin C or other antioxidants in conjunction with minocycline therapy to prevent the formation of the pigment responsible for the staining. CLINICAL SIGNIFICANCE: Minocycline and other tetracycline analogs are well known for causing discoloration of developing teeth in children. However, practitioners must be aware of the tooth staining potential of minocycline in adult populations as well. Studies suggest that the concomitant use of vitamin C may help prevent adult-onset pigmentation caused by minocycline.     

Long-term effects of chemotherapy on orodental structures in children with non-Hodgkin's lymphoma

The aim of this study was to investigate the late effects of treatment for childhood non-Hodgkin's lymphomas (NHL) on oral health and dental development. Thirty-six long-term survivors that had been treated with chemotherapy of childhood NHL were included in this study and 36 volunteers with similar age and sex distribution served as controls. Both groups underwent a complete orodental examination for decayed, missing and filled teeth and surfaces, gingival and periodontal health according to the Loe-Silness Gingival Index and Sillnes-Loe Plaque Index, enamel defects and discolorations, root malformations, eruption status, agenesis, premature apexifications and microdontia. The severity of these disturbances related to age at the time of NHL diagnosis were also evaluated by creating two groups as < 5 yr and > 5 yr. Although none of the parameters altered with age, patients had significantly higher plaque index, more enamel discolorations and root malformations than did the controls. The results show that long-term survivors of NHL patients exhibit some orodental disturbances that may be attributed to the chemotherapy regimens.