[Risk analysis Erosive Tooth Wear (ETW): checklist for a quick assessment of the risk factors for ETW in the dental practice]. / Risikoanalyse Erosive Tooth Wear (ETW): Checkliste zur schnellen Bewertung der Risikofaktoren für ETW in der Zahnarztpraxis.

Erosive Tooth Wear (ETW) is the loss of tooth structure without bacterial involvement. As the resulting loss of tooth structure is irreversible, an early evaluation of the multifactorial etiology, accurate diagnosis and regular follow-up are essential. The ETW is dynamic and its progression should be continuously monitored. A risk analysis table was developed to systematically record risk factors for ETW (Fig. 2). This allows ETW management to be integrated more efficiently into clinical practice and the progression to be documented over the years. If ETW is assumed, the risk analysis should be performed and updated at least every two years. In the assessment, risk-promoting and risk-inhibiting factors are marked, added together and compared. If the negative factors pre-dominate, measures should be taken to minimize the risk for ETW. The main purpose of the risk analysis is therefore to evaluate the individual etiology, coun-teract negative factors, promote positive factors and prevent progression.

Differences in susceptibility of deciduous and permanent teeth to erosion exist, albeit depending on protocol design and method of assessment.

Controversial results showing that deciduous teeth are more susceptible to erosion than permanent teeth might be related to study designs. We investigated how different conditions (pH: 3.0, 4.0, 5.0; acid agitation: gentle or vigorous; acid exposure times: 1-5 min) affect the susceptibility of both teeth to erosion. Enamel specimens (90 deciduous, 90 permanent) were distributed into groups (n = 15 permanent, n = 15 deciduous) according to acid pH (pH 5, 4 or 3) and agitation (gentle or vigorous) during erosive challenge. Both milder (less incubation time, gentle agitation, and higher pH) and more severe (longer incubation times, vigorous shaking, and lower pH) conditions were used. Demineralization was measured by relative surface microhardness (rSMH) and calcium released to the acid. Demineralization increased gradually for both teeth with increasing incubation time, agitation (gentle or vigorous), and with decreasing acid pH. The differences between deciduous and permanent teeth depended on the protocol design and assessment method. Under milder conditions, demineralization was better detectable with rSMH. Under more severe conditions, differences were more perceptible with calcium analyses. Differences exist in the susceptibility to erosion between deciduous and permanent teeth, but they are only distinguishable when the appropriate assessment method is used for the specific erosive condition.

Methods of assessment of early dentine erosion: a review.

Dentine erosion is an increasingly recognised problem, especially in aging population, and various methods have been utilised for its assessment. This narrative review was planned to summarise the methods for the assessment of the early stages of dentine erosion. Relevant original articles published in the English language from 2013 to 2017 were reviewed. Laboratory techniques and methods with in vivo potential were separately studied. It is evident that the assessment of early dentine erosion is complex and requires a combination of methods. For clinical evaluation, chemical analysis and optical methods show great potential but are in need of more validation.

Assessment of oxidative stress in saliva of children with dental erosion.

OBJECTIVE: To evaluate oxidative stress in saliva of children with dental erosion as compared to children with no erosion. METHODS: One single examiner, trained and prepared to make diagnosis of dental erosion according to the Basic Erosive Wear Examination index, selected 40 children aged 4 to 6 years, who attended a pediatric dentistry prevention clinic. Two groups were formed - one comprising children with dental erosion (n=22), and another with no dental erosion (n=18). The quantity of dental biofilm was verified using the Simplified Index of Oral Hygiene, and unstimulated saliva was collected for biochemical analyses. The following were assessed in saliva: flow rate, buffering capacity, pH, and total protein concentration. Malondialdehyde levels were also verified to determine oxidative stress and total antioxidant status. RESULTS: The quantity of biofilm was smaller in children with mean dental erosion±standard deviation (0.76±0.25), as compared to those with no dental erosion (1.18±0.28). There was no statistical difference in saliva parameters of oxidative stress in children with dental erosion. CONCLUSION: The activity of oxidative stress in saliva did not influence dental erosion process when in its early stages.

Assessment of oxidative stress in saliva of children with dental erosion / Avaliação do estresse oxidativo da saliva de crianças com erosão dentária

ABSTRACT Objective To evaluate oxidative stress in saliva of children with dental erosion as compared to children with no erosion. Methods One single examiner, trained and prepared to make diagnosis of dental erosion according to the Basic Erosive Wear Examination index, selected 40 children aged 4 to 6 years, who attended a pediatric dentistry prevention clinic. Two groups were formed - one comprising children with dental erosion (n=22), and another with no dental erosion (n=18). The quantity of dental biofilm was verified using the Simplified Index of Oral Hygiene, and unstimulated saliva was collected for biochemical analyses. The following were assessed in saliva: flow rate, buffering capacity, pH, and total protein concentration. Malondialdehyde levels were also verified to determine oxidative stress and total antioxidant status. Results The quantity of biofilm was smaller in children with mean dental erosion±standard deviation (0.76±0.25), as compared to those with no dental erosion (1.18±0.28). There was no statistical difference in saliva parameters of oxidative stress in children with dental erosion. Conclusion The activity of oxidative stress in saliva did not influence dental erosion process when in its early stages.

RESUMO Objetivo Avaliar o estresse oxidativo da saliva de crianças que possuíam erosão dentária, comparadas àquelas que não apresentavam esta situação. Métodos Um único examinador, treinado e calibrado para o diagnóstico de erosão dentária, segundo o índice de Basic Erosive Wear Examination, selecionou 40 crianças de 4 a 6 anos de idade que frequentavam uma clínica de prevenção de odontopediatria. Dois grupos foram formados - um com aquelas que apresentavam erosão (n=22) e outro sem erosão (n=18). A quantidade do biofilme dental foi obtida utilizando o Índice de Higiene Oral Simplificado, tendo sido feita a coleta de saliva não estimulada para as análises bioquímicas. O fluxo salivar, a capacidade tampão da saliva, o pH salivar e a proteína total da saliva foram avaliados. Também foi verificado o valor do malondialdeído para determinação do estresse oxidativo e o total antioxidante. Resultados A quantidade de biofilme foi menor nas crianças, com erosão dentária média±desvio padrão (0,76±0,25) comparadas àquelas sem erosão dentária (1,18±0,28). Não houve diferença estatística nos parâmetros salivares de estresse oxidativo em crianças com erosão dentária. Conclusão A ação do estresse oxidativo na saliva não influenciou na erosão dentária, quando ainda nos estágios iniciais.

Risk Assessment for Tooth Wear.

Tooth wear has an increasing prevalence in the UK population. The aetiology is commonly multifactorial, and the aetiopathology is through a combination of erosion, attrition, abrasion and abfraction. Erosion is associated with intrinsic or extrinsic acids, and therefore subjects with reflux disease and eating disorders are at increased risk. Fruit juice, fruits and carbonated drink consumption, frequency of consumption and specific habits are also risk factors. Attrition is more prevalent in bruxists. Other habits need to be considered when defining the risk of tooth wear. Abrasion is usually associated with toothbrushing and toothpastes, especially in an already acidic environment. Patients with extensive lesions that affect dentin may be at higher risk, as well as those presenting with unstained lesions. Monitoring of the progress of tooth wear is recommended to identify those with active tooth wear. Indices for tooth wear are a helpful aid.

Avaliação in situ do potencial da solução de AmF/NaF/SnCl2, associada ou não ao laser de CO2, em prevenir a erosão em esmalte dental bovino / In situ assessment of the potential of AmF/NaF/SnCl2 solution, associated or not to CO2 laser irradiation, on preventing dental enamel erosion

Apesar de vários estudos terem demonstrado resultados promissores do uso da solução de AmF/NaF/SnCl2 no controle da erosão do esmalte dental, não existem relatos da sua associação com a irradiação do substrato com o laser de CO2, de comprimento de onda de 9,6 ?m. Desta forma, o presente estudo teve como objetivo avaliar o potencial da solução de AmF/NaF/SnCl2, associada ou não ao laser de CO2 (4,5 J/cm2, 20 Hz, 20 ?s), em controlar a erosão em esmalte dental bovino. Treze voluntários participaram desse estudo in situ, de delineamento cruzado, em 02 fases (04 dias cada), onde 04 tratamentos foram testados utilizando réplicas (n = 13): GC - nenhum tratamento (controle negativo); GF - solução de AmF/NaF/SnCl2 (controle positivo); GL - irradiação com laser de CO2 (9,6 ?m); GLF - laser de CO2 associado à solução de AmF/NaF/SnCl2. Os voluntários usaram dispositivos intra-bucais removíveis contendo 08 amostras de esmalte bovino. Na primeira fase, 07 voluntários utilizaram dispositivos intra-bucais contendo amostras dos grupos GC e GL, e outros 06 voluntários utilizaram dispositivos contendo amostras dos grupos GF e GLF. Na segunda fase, os voluntários foram cruzados, permitindo que todos os grupos experimentais fossem avaliados no meio bucal dos 13 voluntários da pesquisa. Os dispositivos intra-bucais foram removidos da boca para ciclagem erosiva ex-situ em ácido cítrico 0,65%, pH 3,6, durante 4 minutos, 2x/dia, em horários pré-determinados. As amostras foram avaliadas em perfilômetro óptico de não-contato (n = 13) para análise da perda de tecido mineral após o desafio erosivo, e um ensaio de ultramicrodureza transversal (n = 13) foi realizado com o objetivo de determinar a profundidade da área de desmineralização abaixo da superfície do esmalte erodido. A análise morfológica foi realizada utilizando microscopia eletrônica de varredura (MEV) (n = 3).

Os dados foram analisados estatisticamente por meio do modelo ANOVA 2 fatores para medidas repetidas, com subsequente comparação entre os diferentes tratamentos (? = 0,05). A ciclagem ácida realizada no presente estudo provocou perda de esmalte significativamente maior (p < 0,001) nos grupos GC (4,8 ± 1,4A ?m) e GL (4,4 ± 2,0A ?m). Não houve diferença estatística entre a perda de superfície nos grupos GF (1,9 ± 0,9B ?m) e GLF (1,7 ± 0,9B ?m). Os resultados de ultramicrodureza transversal mostraram que as amostras tratadas com a solução fluoretada (grupo GF) apresentaram uma zona parcialmente desmineralizada com média de dureza semelhante às amostras do grupo que não recebeu qualquer tipo de tratamento (grupo GC), com ambos os grupos apresentando média de dureza significativamente maior que os grupos que foram irradiados com o laser de CO2 (GL e GLF) (p < 0,001). As micrografias mostraram que as características morfológicas superficiais do esmalte nos grupos irradiados com laser de CO2 apresentaram-se semelhantes nos grupos GL e GLF, verificando-se a presença de áreas sugestivas de derretimento, resolidificação, microporos e microtrincas, sem evidências de precipitados fluoretados no grupo GFL. Uma camada amorfa pôde ser observada nas superfícies de esmalte tratadas apenas com a solução fluoretada contendo estanho. Pode-se concluir que o uso do enxaguatório bucal fluoretado contendo estanho (500 ppm F-, 800 ppm Sn2+, pH = 4,5) mostrou potencial de prevenção da erosão de esmalte dental. A irradiação do esmalte dental com o laser associado à solução fluoretada mostrou-se eficaz, mas seu efeito não foi sinérgico. O laser de CO2 (9,6 ?m), nos parâmetros utilizados, não foi capaz de prevenir a erosão em esmalte causada por ácido cítrico.

Although several studies have shown promising results using the AmF/NaF/SnCl2 solution in preventing the erosion of dental enamel, there are no reports of their association with the irradiation of the substrate with the CO2 laser, working at 9.6 ?m. Thus, this study aimed to evaluate the potential of AmF/NaF/SnCl2 solution, associated or not to CO2 laser irradiation (4.5 J/cm2, 20 Hz, 20 ?s), to prevent erosion on dental enamel. Thirteen volunteers participated in this 2-phase (4 days each), crossover study, where 04 treatments were tested using replicas (n = 13): GC - no treatment (negative control); GF - AmF/NaF/SnCl2 solution (positive control); GL - CO2 laser irradiation (9.6 ?m); GLF - CO2 laser irradiation associated with AmF/NaF/SnCl2 solution. The volunteers wore removable intra-buccal appliances containing eight bovine enamel samples. In the first phase, seven volunteers used intra-oral appliances containing samples of groups GC and GL and 6 volunteers, appliances containing samples of groups GF and GLF. In the second phase volunteers were crossed over, allowing all experimental groups were evaluated in the buccal environment of the 13 volunteers. Intra-buccal appliances were removed from the mouth and were exposed to a daily ex-situ erosive cycling (0.65% citric acid, pH 3.6, for 4 minutes, 2x/day) at pre-determined times. Samples were evaluated for surface loss using an optical non-contact profilometer (n = 13) for analysis of loss of mineral after the erosive challenge and a cross-sectional nanohardness test (n = 13) was carried out in order to determine the depth of demineralized area below the erosive lesion. Morphological analysis was carried out using scanning electron microscopy (SEM) (n = 3).

Avaliação in situ do potencial da solução de AmF/NaF/SnCl2, associada ou não ao laser de CO2, em prevenir a erosão em esmalte dental bovino / In situ assessment of the potential of AmF/NaF/SnCl2 solution, associated or not to CO2 laser irradiation, on preventing dental enamel erosion

Apesar de vários estudos terem demonstrado resultados promissores do uso da solução de AmF/NaF/SnCl2 no controle da erosão do esmalte dental, não existem relatos da sua associação com a irradiação do substrato com o laser de CO2, de comprimento de onda de 9,6 ?m. Desta forma, o presente estudo teve como objetivo avaliar o potencial da solução de AmF/NaF/SnCl2, associada ou não ao laser de CO2 (4,5 J/cm2, 20 Hz, 20 ?s), em controlar a erosão em esmalte dental bovino. Treze voluntários participaram desse estudo in situ, de delineamento cruzado, em 02 fases (04 dias cada), onde 04 tratamentos foram testados utilizando réplicas (n = 13): GC - nenhum tratamento (controle negativo); GF - solução de AmF/NaF/SnCl2 (controle positivo); GL - irradiação com laser de CO2 (9,6 ?m); GLF - laser de CO2 associado à solução de AmF/NaF/SnCl2. Os voluntários usaram dispositivos intra-bucais removíveis contendo 08 amostras de esmalte bovino. Na primeira fase, 07 voluntários utilizaram dispositivos intra-bucais contendo amostras dos grupos GC e GL, e outros 06 voluntários utilizaram dispositivos contendo amostras dos grupos GF e GLF. Na segunda fase, os voluntários foram cruzados, permitindo que todos os grupos experimentais fossem avaliados no meio bucal dos 13 voluntários da pesquisa. Os dispositivos intra-bucais foram removidos da boca para ciclagem erosiva ex-situ em ácido cítrico 0,65%, pH 3,6, durante 4 minutos, 2x/dia, em horários pré-determinados. As amostras foram avaliadas em perfilômetro óptico de não-contato (n = 13) para análise da perda de tecido mineral após o desafio erosivo, e um ensaio de ultramicrodureza transversal (n = 13) foi realizado com o objetivo de determinar a profundidade da área de desmineralização abaixo da superfície do esmalte erodido. A análise morfológica foi realizada utilizando microscopia eletrônica de varredura (MEV) (n = 3). Os dados foram analisados estatisticamente por meio do modelo ANOVA 2 fatores para medidas repetidas, com subsequente comparação entre os diferentes tratamentos (? = 0,05). A ciclagem ácida realizada no presente estudo provocou perda de esmalte significativamente maior (p < 0,001) nos grupos GC (4,8 ± 1,4A ?m) e GL (4,4 ± 2,0A ?m). Não houve diferença estatística entre a perda de superfície nos grupos GF (1,9 ± 0,9B ?m) e GLF (1,7 ± 0,9B ?m). Os resultados de ultramicrodureza transversal mostraram que as amostras tratadas com a solução fluoretada (grupo GF) apresentaram uma zona parcialmente desmineralizada com média de dureza semelhante às amostras do grupo que não recebeu qualquer tipo de tratamento (grupo GC), com ambos os grupos apresentando média de dureza significativamente maior que os grupos que foram irradiados com o laser de CO2 (GL e GLF) (p < 0,001). As micrografias mostraram que as características morfológicas superficiais do esmalte nos grupos irradiados com laser de CO2 apresentaram-se semelhantes nos grupos GL e GLF, verificando-se a presença de áreas sugestivas de derretimento, resolidificação, microporos e microtrincas, sem evidências de precipitados fluoretados no grupo GFL. Uma camada amorfa pôde ser observada nas superfícies de esmalte tratadas apenas com a solução fluoretada contendo estanho. Pode-se concluir que o uso do enxaguatório bucal fluoretado contendo estanho (500 ppm F-, 800 ppm Sn2+, pH = 4,5) mostrou potencial de prevenção da erosão de esmalte dental. A irradiação do esmalte dental com o laser associado à solução fluoretada mostrou-se eficaz, mas seu efeito não foi sinérgico. O laser de CO2 (9,6 ?m), nos parâmetros utilizados, não foi capaz de prevenir a erosão em esmalte causada por ácido cítrico.

Although several studies have shown promising results using the AmF/NaF/SnCl2 solution in preventing the erosion of dental enamel, there are no reports of their association with the irradiation of the substrate with the CO2 laser, working at 9.6 ?m. Thus, this study aimed to evaluate the potential of AmF/NaF/SnCl2 solution, associated or not to CO2 laser irradiation (4.5 J/cm2, 20 Hz, 20 ?s), to prevent erosion on dental enamel. Thirteen volunteers participated in this 2-phase (4 days each), crossover study, where 04 treatments were tested using replicas (n = 13): GC - no treatment (negative control); GF - AmF/NaF/SnCl2 solution (positive control); GL - CO2 laser irradiation (9.6 ?m); GLF - CO2 laser irradiation associated with AmF/NaF/SnCl2 solution. The volunteers wore removable intra-buccal appliances containing eight bovine enamel samples. In the first phase, seven volunteers used intra-oral appliances containing samples of groups GC and GL and 6 volunteers, appliances containing samples of groups GF and GLF. In the second phase volunteers were crossed over, allowing all experimental groups were evaluated in the buccal environment of the 13 volunteers. Intra-buccal appliances were removed from the mouth and were exposed to a daily ex-situ erosive cycling (0.65% citric acid, pH 3.6, for 4 minutes, 2x/day) at pre-determined times. Samples were evaluated for surface loss using an optical non-contact profilometer (n = 13) for analysis of loss of mineral after the erosive challenge and a cross-sectional nanohardness test (n = 13) was carried out in order to determine the depth of demineralized area below the erosive lesion. Morphological analysis was carried out using scanning electron microscopy (SEM) (n = 3).

Methods for assessment of dental erosion.

Various assessment techniques have been applied to evaluate the loss of dental hard tissue and the surface-softened zone in enamel induced by erosive challenges. In this chapter, the most frequently adopted techniques for analyzing the erosively altered dental hard tissues are reviewed, such as profilometry, measuring microscope techniques, microradiography, scanning electron microscopy, atom force microscopy, nano- and microhardness tests and iodide permeability test. Moreover, methods for chemical analysis of minerals dissolved from dental hard tissue are discussed. It becomes evident that the complex nature of erosive mineral loss and dissolution might not be comprehended by a single technique, but needs application of different approaches for full understanding.

Effects of enamel abrasion, salivary pellicle, and measurement angle on the optical assessment of dental erosion.

The present study assessed the effects of abrasion, salivary proteins, and measurement angle on the quantification of early dental erosion by the analysis of reflection intensities from enamel. Enamel from 184 caries-free human molars was used for in vitro erosion in citric acid (pH 3.6). Abrasion of the eroded enamel resulted in a 6% to 14% increase in the specular reflection intensity compared to only eroded enamel, and the reflection increase depended on the erosion degree. Nevertheless, monitoring of early erosion by reflection analysis was possible even in the abraded eroded teeth. The presence of the salivary pellicle induced up to 22% higher reflection intensities due to the smoothing of the eroded enamel by the adhered proteins. However, this measurement artifact could be significantly minimized (p<0.05) by removing the pellicle layer with 3% NaOCl solution. Change of the measurement angles from 45 to 60 deg did not improve the sensitivity of the analysis at late erosion stages. The applicability of the method for monitoring the remineralization of eroded enamel remained unclear in a demineralization/remineralization cycling model of early dental erosion in vitro.

Oral diagnosis and treatment planning: part 4. Non-carious tooth surface loss and assessment of risk.

Non-carious tooth surface loss or tooth wear is becoming an increasingly significant factor affecting the long-term health of the dentition. The adverse effects of tooth wear are becoming increasingly apparent both in young persons and, as more people retain their teeth, into old age. This situation challenges the preventive and restorative skills of dental practitioners.

Attrition and erosion: assessment and diagnosis.

The management of patients with extensively worn and badly broken down dentitions presents a difficult challenge in dental practice and restorative treatments are often complex, time consuming and costly to implement, so careful case selection and treatment planning is essential. Ultimately the success of any restorative intervention is very dependent on the stability of the oral environment and the status of the remaining tooth structure. Prior to the commencement of any restorative treatment an understanding of the importance of the disease process, the risk factors in the mouth, and the intrinsic and extrinsic factors which affect the oral balance is critical. While there is a growing range of materials and techniques available for cost effective and conservative management of these cases, failure to take a systematic approach to assessment and stabilization may result in early restorative failure, rapid recurrence of the problems and a repeat restoration cycle. Therefore successful management of these patients must include an appropriate mix of preventive and restorative strategies.

The problem with an epidemiological index for dental erosion.

This article reviews and discusses the difficulties posed by the application of epidemiological indices for the measurement of dental erosion. It covers several aspects of index design.

[Assessment of tooth wear depending on Smith and Knight index]. / Evaluarea leziunilor dentare necariogene în functie de indicii Smith si Knight.

UNLABELLED: For the clinical diagnosis of tooth wear Smith and Knight have been suggested the index with the same name, the criteria for the quantification of the hard tissue loss being the size of the area affected and the depth of the defect. The aim of this study was to assess tooth wear depending on Smith and Knight index, on a group of 614 patients. MATERIAL AND METHOD: The criteria for the selection of the patients were the age more than 18 years old and the Smith and Knight index >0. RESULTS: The biggest proportion of tooth wear (47.3%) presented the value 2 of the Smith and Knight index. Most of the tooth wear with Smith and Knight index 3 (54.4%) are abrasions, 71.4% of the tooth wear with Smith and Knight index 1 are attritions, and 20.3% of the tooth wear with Smith and Knight index 3 are erosions. High alcohol consumption is associated with deep tooth wear, exposing dentine (value 2 and 3 of the Smith and Knight index). Currently, various indices are used, making the comparison of the results of prevalence studies difficult.

Assessment and management of dental erosion.

Studies have shown a growing trend toward increasing prevalence of dental erosion, associated with the declining prevalence of caries disease in industrialized countries. Erosion is an irreversible chemical process that results in tooth substance loss and leaves teeth susceptible to damage as a result of wear over the course of an individual's lifetime. Therefore, early diagnosis and adequate prevention are essential to minimize the risk of tooth erosion. Clinical appearance is the most important sign to be used to diagnose erosion. The Basic Erosive Wear Examination (BEWE) is a simple method to fulfill this task. The determination of a variety of risk and protective factors (patient-dependent and nutrition-dependent factors) as well as their interplay are necessary to initiate preventive measures tailored to the individual. When tooth loss caused by erosive wear reaches a certain level, oral rehabilitation becomes necessary.

The evolution of tooth wear indices.

Tooth wear--attrition, erosion and abrasion-is perceived internationally as an ever-increasing problem. Clinical and epidemiological studies, however, are difficult to interpret and compare due to differences in terminology and the large number of indices that have been developed for diagnosing, grading and monitoring dental hard tissue loss. These indices have been designed to identify increasing severity and are usually numerical. Some record lesions on an aetiological basis (e.g. erosion indices), others record lesions irrespective of aetiology (tooth wear indices); none have universal acceptance, complicating the evaluation of the true increase in prevalence reported. This article considers the ideal requirements for an erosion index. It reviews the literature to consider how current indices have evolved and discusses if these indices meet the clinical and research needs of the dental profession.

Methods for assessment of dental erosion.

Various assessment techniques have been applied to evaluate the loss of dental hard tissue and the surface-softened zone in enamel induced by erosive challenges. In this chapter, the most frequently adopted techniques for analyzing the erosively altered dental hard tissues are reviewed, such as profilometry, microradiography, scanning electron microscopy, atom force microscopy, nano- and microhardness tests and iodide permeability test. Moreover, methods for chemical analysis of minerals dissolved from dental hard tissue are discussed. It becomes evident that the complex nature of erosive mineral loss and dissolution might not be comprehended by a single technique, but needs application of different approaches for full understanding.

An assessment of stress analyses in the theory of abfraction.

Wedged-shaped lesions at the cemento-enamel junction of teeth have been attributed primarily to biomechanical loading forces that cause flexure and failure of enamel and dentin. This theory, termed abfraction, remains controversial. This review examined studies on mechanical properties of enamel and dentin and studies on bite forces and mastication as background information. Abfraction is based principally on a few early finite element analysis and photoelastic models showing stress concentration at the dental cervical area without actually showing enamel and dentin fracture. However, a review of more recent dental stress analyses has been contradictory. Particularly, analyses of the periodontal ligament and alveolar bone, not modeled in previous studies, have shown that those structures may dissipate occlusal loading forces from the cervical areas. In addition, some models may not fully represent intricate dental anatomy and complex occlusal function. Therefore, the key basis of the abfraction theory may be flawed.

The diagnostic accuracy and reproducibility of school dental screening using an index of treatment need.

OBJECTIVE: To test the use of an index in school screening programmes by assessing its accuracy in determining treatment need, and its reproducibility. BASIC RESEARCH DESIGN: Diagnostic accuracy was measured against a gold standard, inter-examiner and intra-examiner variation was measured by comparing the results of two examiners for the same subjects. Setting A large inner city primary school in Birmingham. PARTICIPANTS: 570 primary school children. OUTCOME MEASURES: Diagnostic accuracy was measured by sensitivity and specificity values. Reproducibility was measured by using kappa scores. RESULTS: The mean sensitivity for positive screening result was 81% and mean specificity for negative screening result was 97%. The kappa score for inter-examiner variation was 0.7 with agreement on decision to refer in 91% of cases. Intra-examiner variation was 11% for both examiners. CONCLUSION: The use of the index was shown to be both accurate and reproducible and is advocated for use in school dental screening programmes.