Search

Regressive dental changes appear to be suitable for age assessment in living adults. In 2012, Olze et al. showed that several criteria presented by Gustafson for extracted teeth can also be applied to orthopantomograms. The objective of this study was to test the applicability and reliability of this method in a Chinese population. For this purpose, 1300 orthopantomograms of 650 female and 650 male Chinese aged between 15 and 40 years were evaluated. The characteristics of secondary dentin formation, periodontal recession, attrition, and cementum apposition were reviewed in all the mandibular premolars. The sample was split into a training and test dataset. Based on the training set, the correlation of the individual characteristics with chronological age was studied with a stepwise multiple regression analysis, in which individual characteristics formed the independent variable. According to the results, the R values amounted to 0.80 to 0.83; the standard error of estimate was 4.29 to 4.75 years. By analyzing the test dataset, the accuracy of the present study, Olze's and Timme's formulas were determined by the difference between the estimated dental age (DA) and chronological age (CA). Taking both mean differences and mean absolute differences into account, the Chinese age estimation formula did not always perform better compared with Olze's and Timme's formulas for both males and females. It was concluded that this method can be used in Chinese individuals for age assessment. However, the applicability of the method is limited by the quality of the X-ray images, and the method should only be applied by experienced forensic odontologists.

In recent years, the importance of dental erosion – the demineralisation of teeth without the involvement of bacteria – has increased. It has been shown that erosion always involves abrasion.

Statement of Problem: A valid system for assessing and classifying functional occlusion has not been established. The prevalence of anterior protected articulation is not known., Purpose: The purpose of this study was to quantify the prevalence of various functional occlusal contact patterns, including anterior protected articulation, among dental students., Material and Methods: Occlusal contacts were examined during lateral excursions from the maximal intercuspal position to the canine-to-canine position in 100 young adults. A combination of 3 common clinical methods was used: a visual examination, articulating paper, and feedback from the participants., Results: Data from 3 classification systems were analyzed: (1) Occlusal contacts on the working side only – canine protected articulation was present in 25% of laterotrusions; anterior protected articulation was present in 18.5% of laterotrusions. Group function was present in 56% of laterotrusions. Other schemes were present in 0.5% of laterotrusions. (2) Contacts on both the working and the nonworking side. (3) Contacts on the working and nonworking side during both right and left laterotrusion. Nonworking side contacts were present in 33% of the participants. Nonworking side interference was present in 1 participant., Conclusions: The prevalence of anterior protected articulation found in this study was high enough to allow anterior protected articulation to be considered one of the fundamental working side occlusal contact patterns. More studies will be necessary to confirm this finding., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

The Basic Erosive Wear Examination (BEWE) is a practical index for screening tooth wear, using a 4-point ordinal scale (0-3). The highest score is recorded in each sextant and a total score (or BEWE sextant cumulative) is calculated per subject. This study aims to investigate if the BEWE sextant cumulative score compares to one comprising a percentage score from all tooth surfaces and as a highest BEWE per subject. The aim is to assess the validity of this score. A total of 350 subjects were recruited from hospital and general practice in south-east England. Buccal, occlusal and lingual/palatal BEWE scores were collected and percentages calculated based on scores 1, 1 and above, 2 and above and 3. BEWE sextant cumulative scores and highest BEWE scores were also recorded per subject. Spearman's correlation coefficients (p values) assessed the relationship between BEWE sextant cumulative scores, BEWE percentages and BEWE highest score per subject. The BEWE sextant cumulative score correlates significantly to a BEWE score taken as a percentage score from all tooth surfaces (Spearman's r > 0.5, p < 0.001) and especially to BEWE surface scores of 1 and above and 2 and above (r > 0.8, p < 0.001) and as a highest surface score per subject (r > 0.8, p < 0.001). BEWE sextant score provides a representation of tooth wear on all tooth surfaces. This study validates a tooth wear index, which provides clinicians with risk indicators of a patient's level of tooth wear and may help to guide clinical management.

Aim: The aim of this study was to assess the prevalence of tooth wear in young adults in Poland., Methods: A total of 1,886 persons aged 18 years, selected on a basis of multistage sampling, were examined within the Nationwide Dental Health Monitoring Programme. Previously calibrated dentists measured tooth wear using the BEWE-scoring system (Basic Erosive Wear Examination)., Results: Out of 1,886 young adults, 42.2% presented the signs of dental erosion. Considered the severity of erosion, it was graded as 1, 2 and 3 in 28.9%, 11.9% and 1.5% of 18-year-olds, respectively., Conclusions: Results of clinical assessment of dental erosion in 18-year-old young adults revealed that erosive tooth wear is an important problem in this age group. Of them, 13.4% had signs of advanced tooth wear which may lead to serious clinical problems in the future.

Objective: The aim of the study was to determine the prevalence and awareness of particular types of oral parafunctions in young healthy students and any association with temporomandibular disorders (TMD)., Material and Methods: The study was performed in a randomly selected group of 303 healthy students (mean age 18.8 years) from the vocational technical school in Wrocław, Poland, who underwent a routine clinical examination and functional analysis of the mouth. On taking the history all subjects were asked about their awareness of various forms of parafunctional activity in their mouth., Results: Almost all subjects revealed various oral parafunctions such as: bruxism, nail and pen biting, chewing gum, and biting the mucosa of lip or cheek. These habits were present singly or as double, triple or even fourfold coincidences in a single person. The most frequent oral parafunctions were habitual gum chewing and bruxism. Subjects were very seldom aware of the last parafunction. TMDs were more prevalent in the presence of bruxism than in other oral parafunctions., Conclusions: The studied students revealed various types of oral parafunctions, however most of them were not aware of clenching and grinding their teeth.

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.

The present-day terminology and definitions of tooth wear are not unambiguous. For diagnosing tooth wear, however, it is essential that they are unambiguous. In this article a proposal is presented for a tooth wear evaluation system with simplified definitions. This system consists ofa number of modules and can be used for various aspects of the diagnostic procedure. It can be used for the quantification of tooth wear, both for periodic screening and for the monitoring of tooth wear in individual patients. The scoring of occlusal/incisal tooth wear as well as of non-occlusal/non-incisal tooth wear is possible. The evaluative system is also suitable for determining which type of tooth wear, such as attrition, abrasion and erosion, is most likely to have caused any observed loss of hard tooth tissue.

Objective: Controversy exists concerning the etiological factors behind degenerative changes in the temporomandibular joints (TMJs). Tooth attrition, occlusal support, food consistency, ageing, gender and genetics are some possible causative factors that have been discussed in the literature. The aim of this study was to examine contemporary human skull material for possible relations between degenerative form and surface changes in the TMJs in relation to occlusal support., Material and Methods: The material consisted of 259 human skulls from 170 males and 89 females, with an age range of 18-100 years., Results: Dental status was in general poor, and 22% of skulls were edentulous. Form and surface changes of both the condyles and the temporal components were more common in the present material compared to that in most previous studies. In males, irrespective of age, only weak and clinically insignificant correlations could be found between degenerative TMJ changes and occlusal support. In women, however, the correlations between these variables were in general much stronger, especially at higher ages., Conclusions: The present findings do not lend support to the hypothesis that loss of occlusal support is a causative factor for degenerative changes in the TMJs in male subjects. In women, such a correlation was obvious in the present sample, at least at higher ages. It can be speculated that hormonal factors play a role in the sex difference found.

The reliability of a newly developed tooth wear grading system was assessed both clinically and on dental casts by two observers using 20 participants. The reliability of clinical occlusal/incisal tooth wear grading was fair-to-good to excellent, while that of most of the clinical nonocclusal/nonincisal grades was at least fair-to-good. Dental cast assessment frequently yielded poor reliabilities, especially for nonocclusal/nonincisal surfaces. Hence, occlusal/incisal wear could be graded more reliably than nonocclusal/nonincisal wear, while the clinical assessment of tooth wear was more reliable than the grading of dental casts.

A modified wear index, in which the wear of enamel and dentine are recorded separately, is described. The index was applied to estimating the prevalence and extent of tooth wear in a single convenience sample of 18- to 30-year-old students attending a university in London. The subjects were examined under good lighting in a dental chair away from a dental school. A total of 707 females and 303 males were recruited with a mean age of 21.9 years (standard deviation = 0.1, range = 18-30) and examined by 3 trained and calibrated examiners. Intra-examiner intra-class correlation coefficients showed a range of 0.44-0.88. The unweighted kappa scores were above 0.88 for enamel and dentine. The presence of enamel wear was common to all subjects, but 6.1% of the participants had more than one third of the tooth surface affected. Dentine was exposed on 5.3% of all surfaces, with the largest proportion accounting for less than 10% of the tooth surface (grade 1). The proportion of subjects with at least 1 surface with dentine exposed was 76.9% of the total population. The males had significantly more wear in dentine than the females (p = 0.001). The inter-examiner intra-class correlation coefficients for enamel and dentine were 0.87 and 0.92, respectively. The reproducibility of the index was comparable to other analyses and provides an opportunity to assess the prevalence of enamel wear in large population-based studies., (2009 S. Karger AG, Basel.)

Purpose: The aim of this study was to quantitatively measure tooth and ceramic wear over a 2-year period using a novel superimposition technique. Three ceramic systems--experimental hot-pressed ceramic (EC), Procera AllCeram (PA), and metal-ceramic--were used., Materials and Methods: A total of 90 posterior crowns in 48 patients were randomized into 3 groups, and impressions were made at baseline and at 6-month intervals for 2 years. Clinical images were taken after using a dye to highlight surface changes. The impressions were digitized and modeled as superimposable 3-dimensional colored surface images. The depth of wear at the occlusal contact areas was quantitatively measured at 6, 12, 18, and 24 months., Results: The quantitative evaluation showed more wear in Procera AllCeram at the occlusal contact areas, whereas the experimental and metal-ceramic systems showed less wear. There was a significant difference in the amount of enamel worn between all types of restorations (P < .05). There was a statistically significant difference (P < .05) in the mean depth of wear between all systems., Conclusions: The metal-ceramic and experimental systems showed less change, indicating improved wear resistance compared with Procera AllCeram. In addition, enamel opposing metal-ceramic and experimental crowns showed less wear compared to enamel opposed by Procera AIICeram crowns.

The problem of erosive tooth wear appears increasingly to be encountered by clinicians and researchers. An adequate way of defining and recording erosive tooth wear is essential in order to assess the extent of this clinical phenomenon, both on an individual level and in the population, and for the adequate provision of preventive and therapeutic measures. Well-established erosion indices have been used in most of these studies, although in many cases modifications have been made to suit the different research aims. This use of different indices is one reason why it still cannot be claimed that there is enough current knowledge on this clinical phenomenon. This article summarises the proceedings of a workshop to discuss the topic of dental erosion indices. The result of the workshop is the proposal for a new scoring system (Basic Erosive Wear Examination, BEWE) designed for use both within the research field and for dental clinicians, with the aims of standardising assessment of erosion for international comparisons, raising awareness and providing guidelines for treatment of erosive tooth wear in dental practice.

In principle, there is agreement about the clinical diagnostic criteria for dental erosion, basically defined as cupping and grooving of the occlusal/incisal surfaces, shallow defects on smooth surfaces located coronal from the enamel-cementum junction with an intact cervical enamel rim and restorations rising above the adjacent tooth surface. This lesion characteristic was established from clinical experience and from observations in a small group of subjects with known exposure to acids rather than from systematic research. Their prevalence is higher in risk groups for dental erosion compared to subjects not particularly exposed to acids, but analytical epidemiological studies on random or cluster samples often fail to find a relation between occurrence or severity of lesions and any aetiological factor. Besides other aspects, this finding might be due to lack of validity with respect to diagnostic criteria. In particular, cupping and grooving might be an effect of abrasion as well as of erosion and their value for the specific diagnosis of erosion must be doubted. Knowledge about the validity of current diagnostic criteria of different forms of tooth wear is incomplete, therefore further research is needed.

Within the context of preventing non-communicable diseases, the World Health Report (2002) and the WHO Global Oral Health Program (2003) put forward a new strategy of disease prevention and health promotion. Greater emphasis is placed on developing global policies in oral health promotion and oral disease prevention. The Decayed, Missing, Filled Teeth (DMFT) index does not meet new challenges in the field of oral health. Dental erosion seems to be a growing problem, and in some countries, an increase in erosion of teeth is associated with an increase in the consumption of beverages containing acids. Therefore, within a revision of the WHO Oral Health Surveys Basic Methods, new oral disease patterns, e.g. dental erosion, have to be taken into account. Within the last 20 years, many studies on dental erosion have been carried out and published. There has been a rapid growth in the number of indexes quantifying dental erosion process in different age groups. However, these indexes are not comparable. This article discusses quality criteria which an index intended for assessing tooth erosion should possess.

Quantifying tooth wear in general and erosion in particular mostly is made by distinguishing between lesions restricted to enamel and lesions reaching the underlying dentine. Various scores for grading have been used, but in all systems, higher scores are given in cases of exposed dentine, thus, indicating a more severe stage of the condition. Clinical diagnosis of exposed dentine is made by assessing changes in colour or optical properties of the hard tissues. This paper aims to review the literature and discuss critically problems arising form this approach. It appears that classifying the severity of erosion by the area or depth of exposed dentine is difficult and poorly reproducible, and taking into account the variation of enamel thickness, the amount of tissue lost often is not related simply to the area of exposed dentine. There has still been very little longitudinal investigation of the significance of exposed dentine as a prognostic indicator. Further work and discussion is needed to reevaluate the explanative power of current grading procedures.

A new scoring system, the Basic Erosive Wear Examination (BEWE), has been designed to provide a simple tool for use in general practice and to allow comparison to other more discriminative indices. The most severely affected surface in each sextant is recorded with a four level score and the cumulative score classified and matched to risk levels which guide the management of the condition. The BEWE allows re-analysis and integration of results from existing studies and, in time, should initiate a consensus within the scientific community and so avoid continued proliferation of indices. Finally, this process should lead to the development of an internationally accepted, standardised and validated index. The BEWE further aims to increase the awareness of tooth erosion amongst clinicians and general dental practitioners and to provide a guide as to its management.

Anthropologists have for many years considered human tooth wear a normal physiological phenomenon where teeth, although worn, remain functional throughout life. Wear was considered pathological only if pulpal exposure or premature tooth loss occurred. In addition, adaptive changes to the stomatognathic system in response to wear have been reported including continual eruption, the widening of the masticatory cycle, remodelling of the temporomandibular joint and the shortening of the dental arches from tooth migration. Comparative studies of many different species have also documented these physiological processes supporting the idea of perpetual change over time. In particular, differential wear between enamel and dentine was considered a physiological process relating to the evolution of the form and function of teeth. Although evidence of attrition and abrasion has been known to exist among hunter-gatherer populations for many thousands of years, the prevalence of erosion in such early populations seems insignificant. In particular, non-carious cervical lesions to date have not been observed within these populations and therefore should be viewed as 'modern-day' pathology. Extrapolating this anthropological perspective to the clinical setting has merits, particularly in the prevention of pre-mature unnecessary treatment.

Purpose: One of the barriers to restoring an edentulous space may be the supraeruption of an unopposed tooth to occupy some or all of the space needed for prosthetic replacement. The aim of this study was to determine the extent and type of supraeruption associated with unopposed posterior teeth and to investigate the relationship between these and oral and patient factors., Materials and Methods: Diagnostic casts of 100 patients with an unopposed posterior tooth and of 100 control patients were scanned and analyzed to record the extent of supraeruption, together with other clinical parameters. The type of eruption present was defined for each subject as Periodontal Growth, Active Eruption, or Relative Wear. Generalized Linear Models were developed to examine associations between the extent and type of supraeruption and patient or dental factors. The extent of supraeruption for an individual was modeled to show association between the degree of supraeruption and clinical parameters. Three models were produced to show associations between each type of supraeruption and clinical parameters., Results: The mean supraeruption for subjects was 1.68 mm (SD 0.79, range 0 to 3.99 mm) and for controls, 0.24 mm (SD 0.39, range 0 to 1.46 mm). The extent of supraeruption was statistically greater in maxillary unopposed teeth than in mandibular unopposed teeth. Supraeruption was found in 92% of subjects' unopposed teeth., Conclusions: A Generalized Linear Model could be produced to demonstrate that the clinical parameters associated with supraeruption are periodontal growth, attachment loss, and the lingual movement of the tooth distal to the extraction site. Three types of supraeruption, which may be present singly, or in combination, can be identified. Active eruption has an association with attachment loss. Periodontal growth has an inverse association with attachment loss, is more prevalent in younger patients, in the maxilla, in premolars, and in females. Relative wear has an association with increasing age and is more prevalent in unopposed mandibular teeth.

Objectives: The purpose of this study was to investigate the prevalence of signs and symptoms of temporomandibular disorders in Nigerian patients with and without occlusal tooth wear, and to relate the signs and symptoms with the severity of occlusal tooth wear., Methods: One hundred and fifty patients with occlusal tooth wear, and 100 control subjects participated in this study (mean age 40.8 +/- 12.2 years, range 18-65 years). Exclusion criteria included patients and subjects with more than one missing opposing pair of premolars or molars, restorations covering the entire incisal edge, canine cusps and occlusal surfaces of premolars and molars. The severity of occlusal wear was assessed using the tooth wear index (TWI) designed by Smith and Knight (1984). Chi-square test was used to compare the differences in signs and symptoms of TMD. P < 0.05 was defined as significant., Results: Although more females reported pain than males the difference was not statistically significant (p = 0.05). Except for impaired range of movement, tooth wear patients and controls differ significantly with respect to the variables; pain report, pain on palpation, TMJ sound and deviation on opening (p < 0.001). Patients with mean occlusal TWI score of > or =3 differ significantly from those with TWI score < or =2 with respect to pain on palpation and TMJ sound (p < 0.001)., Conclusions: Posterior occlusal wear (mean TWI scores of 3 or 4) was significantly associated with pain on palpation and TMJ sound. Hence there may be a clinically relevant risk of TMD among Nigerian patients with occlusal tooth wear.

Statement of Problem: Bruxism is purported to be a risk factor for temporomandibular disorder (TMD) pain, but the association requires clarification., Purpose: The purpose of this study was to investigate the relation between anterior tooth wear as an indicator for bruxism and the presence of TMD pain., Material and Methods: Study subjects included 646 participants (age range 35 to 44 years) of a national oral health survey in Germany. Anterior tooth wear was registered for each anterior tooth with a 4-point scale (none, mild, moderate, and severe wear). Temporomandibular disorder was defined as self-reported pain in the face, jaw muscles, and/or temporomandibular joint (TMJ) during the last month, according to either the German version of the Research Diagnostic Criteria for Temporomandibular Disorders or the response to a question about pain in the masticatory muscles or the TMJ according to the Helkimo-Index. A multiple logistic regression analysis, controlling for the effects of age and gender, investigated the linear relationship between increased tooth wear and the risk of TMD pain., Results: After adjusting for age and gender, an odds ratio of 1.11 (95% confidence interval: 0.7-1.8) indicated that the risk of TMD pain increased an estimated 11% per unit increase of tooth wear. There was no statistically significant or clinically relevant relationship between a linear increase of tooth wear and risk of TMD pain., Conclusion: Anterior tooth wear was not associated with self-reported TMD pain in 35- to 44-year-old subjects. Using anterior tooth wear as an indicator for long-term bruxing behavior, a clinically relevant dose-response relationship between this type of bruxism and TMD pain does not appear to exist.

ADHD is a neuropsychological disorder, affecting attention, impulsiveness and activeness. The study included 36 children with ADHD, 47 without, and two silent observers. A dental form, SNAP-IV and ADHDT symptom checklists were used. Statistically significant differences were observed in hospitalization histories, oral habits, tongue characteristics, and facial biotype. Differences in orofacial characteristics and behavior between the groups were confirmed.

Literature data describe the impact of certain factors on oral health. Very well known is habitual chewing of different plant products, including tobacco, which depending on the geographical area and the substances used, have various names. It has been estimated that approximately 200 million residents of the West Pacific Rim and South-East Asia indulge in betel chewing. Betel is composed of a leaf of the betel pepper, lime, tobacco and the nut of the areca palm. This study aimed to assess the degree of abrasive changes in residents of the Korunalaya Leprosy Care Center. The examinations were carried out on 85 patients (45 females and 40 males), aged 35-95 years, at the local dental surgery. Patients had their teeth assessed and they were further interviewed as to the duration of their habit with regard to their sex and age (35-44; 45-64 and > or = 65 years). The abrasive changes were evaluated using Gerasimov's 7-degree scale. Interview data indicate that 71.76% of the patients were habitual betel chewers. Among female patients, third-degree abrasion was the most frequent change while among males--fifth degree (53.3% and 45.0%, respectively). The abrasive changes, increasing with age, can be attributed to the duration of betel chewing. It is worth noticing that a vegetarian diet can be a contributing factor to abrasion as most of the food consumed by Hindus are plants.

It is the aim of this study to determine the pattern and degree of tooth wear in the elderly population in the South East Local Government Area in Ibadan. The study was carried out on 690 elderly individuals who were 65 years old and above, living in various wards in South East Local Government Area, in Ibadan. A multistage sampling technique was used to select elderly individuals for the study. Two interviewers, 2-record clerks and 2 examiners were trained for the study and the examiners were calibrated. The index of Eccles J.D was used to determine the severity of tooth wear. The results highlight the high prevalence of tooth wear, mainly attrition in the elderly in this local government area. Six hundred and forty (92.8%) of the elderly had tooth wear. Of these 58.59% were males and 41.41% females. Attrition was observed in 618 (89.6%) elderly individuals. The mandible exhibited a higher prevalence of tooth wear than the maxilla and was statistically significant. Severe tooth wear was observed in only 5.74% of the teeth whilst moderate and mild tooth wear were observed in 26.91% and 30.88% respectively. Unlike the Western European countries, attrition being the most common type of tooth wear in these elderly individuals suggests that the aetiological factors responsible for tooth wear are different. Common habits such as crushing of bones and chewing of sticks for routine oral hygiene care could be contributing factors to tooth wear in this environment.

Statement of Problem: The etiology of noncarious cervical lesions is not well understood. An understanding of the etiology helps the clinician determine appropriate treatment and management strategies. Purpose This study evaluated the relationship between noncarious cervical lesions and occlusal (or incisal) wear., Material and Methods: Casts (n = 299) made from dental students were articulated in a semi-adjustable articulator and evaluated. Data included the presence and contour of noncarious cervical lesions (NCLs) and the presence, location, and severity of any occlusal/incisal wear facets. Also included were Angle's classification, occlusal guidance patterns, midline, presence of tori, tooth restoration, reverse articulation (crossbite), open occlusal relationship, and posterior excursive contacts where present. Following a calibration procedure, 2 evaluators made independent observations on the casts. The first evaluator recorded for each tooth in each subject: presence and severity of NCLs, presence and extent of occlusal/proximal restorations, and presence of reverse articulation and open occlusal relationship. Following the first evaluation red rope wax was placed at the cervical margins of each tooth for the purpose of blinding the second evaluator from NCL observations. The second evaluator recorded severity and location of occlusal/incisal wear, presence or absence of posterior excursive contacts, Angle's classification, occlusal guidance pattern, any midline discrepancy, and presence or absence of tori. The Spearman correlation coefficient and chi 2 tests were used to analyze the data (alpha=.05)., Results: There was no relationship between noncarious cervical lesions and occlusal/incisal wear. There was also no correlation between NCLs and other parameters examined., Conclusions: Under the conditions of this study, noncarious cervical lesions are not related to occlusal wear.

An Index of Oral Health (OHX) was developed by Burke and Wilson in the mid 90s. Use of the index involves assessing patient comfort and satisfaction in addition to the assessment of caries, periodontal disease, toothwear, mucosa, occlusion and dentures, where appropriate. On completion of this structured examination, the clinician arrives at an overall oral health index (OHX) for the patient, which is expressed as a fraction of the maximum achievable score. The index was modified by Denplan UK by amending the calculations to produce the Oral Health Score (OHS). The Reproducibility of the OHX and OHS was tested at Birmingham Dental Hospital and School during 2001 and 2002 and was found to be satisfactory. The dentists' opinions on the OHX and OHS were assessed by means of questionnaires. Most of the dentists felt that both were easy to use.

Overview: The authors propose updated and revised nomenclature, definitions and classification for tooth surface lesions. Their objective is standardization, clarity and clinical utility for the dental practitioner. The article presents a schema of the pathodynamic mechanisms in the formation of tooth surface lesions--three basic physical and chemical mechanisms, their interactions and their dental manifestations., Conclusions and Clinical Implications: The use of precise definitions will assist the practitioner in determining the etiology of various tooth surface lesions. Understanding the pathodynamic mechanisms and their many possible interactions, as set forth in the schema, will enable the practitioner to make an accurate differential diagnosis and to provide effective prevention and treatment. It also will assist dentists in communicating more effectively with their colleagues as well as with their patients. In addition, the schema helps identify areas in which future research is indicated.

Purpose: The aim of this study was to verify the hypothesis that shortened dental arches constitute a risk to occlusal stability., Materials and Methods: Using cluster samples, 725 subjects with shortened dental arches comprising intact anterior regions and zero to eight occluding pairs of posterior teeth and 125 subjects with complete dental arches were selected. Subjects with shortened dental arches were classified into eight categories according to arch length and symmetry. Parameters for occlusal stability were interdental spacing, occlusal tooth wear, occlusal contact of incisors in intercuspal position, and vertical and horizontal overlap. Additionally, tooth mobility and overeruption of unopposed teeth were assessed. Influence of independent variables (dental arch category, age, gender, and residence) on the parameters for occlusal stability was assessed by one-way ANOVA and Tukey's multiple range tests., Results: Extreme shortened dental arches (zero to two pairs of occluding premolars) had significantly more interdental spacing, occlusal contact of incisors, and vertical overlap compared to complete dental arches. Occlusal wear and prevalence of mobile teeth were highest in these categories. The category with three to four occluding premolars had significantly more interdental spacing and, for the older age group, more anterior teeth in occlusal contact compared to complete dental arches. Age was consistently associated with increased changes in occlusal integrity., Conclusion: Signs of increased risk to occlusal stability seemed to occur in extreme shortened dental arches, whereas no such evidence was found for intermediate categories of shortened dental arches.

Objective: To establish the prevalence and severity of tooth wear among Nigerians and to compare the pattern and aetiology with findings of earlier studies in Western populations., Design: Clinical examinations for tooth wear using the tooth wear index (TWI)., Setting: The Federal Republic of Nigeria., Participants: Patients attending the Dental Hospital, Obafemi Awolowo University Teaching Hospital's Complex Ile-Ife., Outcome Measures: Attrition, abrasion and erosion., Results: Of the 126 patients with tooth wear 81 had attrition, 20 had abrasion, 9 had erosion and 16 had attrition and abrasion combined. A total of 15,480 tooth surfaces were examined. 2,229 (14.4%) surfaces had tooth wear out of which 1,007 (6.5%) were pathologically worn down. The frequency of tooth wear increased with the age of patients. Most of the pathologically worn surfaces were just one point above maximum acceptable value., Conclusions: The aetiological factors associated with tooth wear are not different from those encountered in Western cultures but the pattern of wear differs. Pathological tooth wear presents as an age related phenomenon and is probably more severe in Nigerians.

Background: The distribution of lesions from dental erosion due to intrinsic acid regurgitation and vomiting may be different from patterns of dental erosion due to extrinsic acids. To date studies have failed to validate this assumption. This study described the sites and nature of lesions from dental erosion in cases of intrinsic acid regurgitation, and compared them with the distribution of lesions occurring in age and sex matched controls, whose lesions are due to extrinsic acids., Methods: The University of Queensland tooth wear clinic patients were screened to select 30 cases, 21 self-identified bulimics and nine medically diagnosed chronic gastric acid regurgitators, and 30 controls. Epoxy resin models of the subjects' dentition were examined under stereoscopic light microscope at magnification 16 to 40. The patterns and sites of tooth wear were recorded for teeth representative of 20 tooth sites in every subject., Results: While the incisal edges of maxillary and mandibular anterior teeth of acid regurgitators were more frequently affected by erosion, incisal attrition was more common on controls' teeth. Cervical lesions were more commonly found in association with incisal attrition in the controls, and in association with incisal erosion in the cases. In 10 per cent of sites in case subjects, cervical lesions associated with incisal erosion were found on the lingual aspects of their mandibular incisors, canines and premolars. These lesions were almost exclusive to the case subjects., Conclusions: These results validate that lingual cervical lesions associated with incisal erosion on the mandibular anterior teeth are strong discriminators between tooth wear in patients with bulimia nervosa or chronic gastro-oesophageal reflux and those whose dental erosion is due to extrinsic acids.

This part of the series is devoted to tooth surface loss (TSL) not caused by caries or trauma. The management of this form of generalised TSL is included in this series because knowledge of occlusion is needed for both the diagnosis and, when indicated, treatment. There are, however, many other factors involved in the management of generalised TSL other than those associated with 'occlusion'. These will also be discussed.

Acid demineralization of teeth causes occlusal erosion and attrition and associated non-carious cervical lesions at sites relatively unprotected by saliva. Associations of occlusal pathology and cervical lesions were looked for in 450 patients with toothwear, and 174 subjects with cervical lesions were identified. Associations of occlusal attrition, or erosion, or no wear, with cervical lesions at 72 buccal and lingual sites were recorded from epoxy resin replicas of the subjects' dentitions (3241 teeth). Criteria used to discriminate occlusal erosion from attrition; and shallow from grooved and wedge-shaped cervical lesions were delineated by scanning electron microscopy (SEM). In the absence of occlusal pathology, cervical lesions were very rare (<1%). In the presence of occlusal pathology, cervical lesions were present in 27.71% of buccal sites as opposed to 2.61% of lingual sites. The commonest site of cervical lesions was the facial of maxillary incisors (36% of sites). The least common site was the lingual aspect of mandibular molars (1.7% of sites). These differences may reflect the normal protective role of serous saliva and salivary pellicle in a site-specific manner, on the lingual surfaces of mandibular teeth particularly, and do not support abfraction as the prime aetiology of cervical lesions.

Patients requiring extensive restorative care frequently exhibit significant loss of tooth structure. Specific clinical findings in an extremely worn dentition may vary widely and are often confusing. Severe wear can result from a mechanical cause, a chemical cause, or a combination of causes. The location of the wear, the accompanying symptoms and signs, and information gained from the patient interview are essential components in determining the etiology. A diagnostic decision tree facilitates a systematic analysis and diagnosis of dental wear., (Copyright 2001 by The American College of Prosthodontists.)

The chewing cycle is a functional movement, closely related to occlusion, the neuromuscular system and the central nervous system. Although actual chewing paths are complicated and vary from individual to individual, there are two typical patterns. One is more vertical in nature and is similar to a chopping movement. The other is a more lateral type that is similar to a grinding movement. The purpose of this study was to evaluate the effects of chewing patterns on occlusal wear. Fifteen subjects exhibiting a chopping-chewing pattern and 15 subjects exhibiting a grinding-chewing pattern were selected using a jaw tracking device. The occlusal wear values, obtained by both ordinal and Woda's arbitrary scales, and frequencies of non-working facets were calculated for each group. The occlusal wear values in all teeth and in each segment, obtained by the use of the ordinal scale did not vary significantly between the chopping and the grinding type group. However, the occlusal wear values of the grinding type group in all teeth and in posterior teeth segments, obtained by the use of Woda's arbitrary scale, were significantly greater than those of the chopping type group. Frequencies of non-working facets in posterior teeth showed no significant differences between the groups.

The purpose of this study was to investigate the pattern of toothwear in the permanent teeth of 12-18-year-old Nigerian students. The study group comprised 176 individuals (67 males and 109 females) who had no carious cavity, restoration or fracture on any of their permanent teeth. Within the group, 86% had tooth surface loss that was limited to enamel and dentine. No statistically significant differences were observed between the sexes. The most commonly affected tooth was the lower first molar, while the occlusal surface was the most frequently involved. One student had toothwear with a predominantly erosive component as a result of frequent ingestion of low pH drinks, while another displayed toothbrush abrasion. Of those with toothwear, two (13.4%) had parafunctional activities. The cause of toothwear in 73.2% of the study population could not be ascertained. Some of it may be connected with the coarse, abrasive diets that many of the students admitted to consuming on a regular basis.

Purpose: This study evaluated the wear area of human enamel opposing 2 conventional and 2 low-fusing dental porcelains, as well as abrasive wear, attrition, surface hardness, and fracture toughness for the 4 porcelain substrates., Materials and Methods: Two low-fusing and 2 conventional metal-ceramic porcelains were used to form 15-mm-diameter disks (n = 10), which were fired according to manufacturer's recommendations. Enamel cusps (n = 40) were formed from extracted third molars. All ceramic and enamel specimens were finished to a 1000-grit silicon carbide surface. The Oregon Health Sciences University (Portland, OR) oral wear simulator was used to deliver a 20-N load from the cusps to the ceramic substrates through a food-like slurry. The sliding action of the cusps over an 8-mm linear path produced abrasive wear. A static 70-N load was applied at the end of the path to create attrition. This sequence was repeated at 1.0 Hz for 50,000 cycles. Ceramic wear was measured with a profilometer (+/-2 micrometers), and enamel wear was evaluated using optical scanning methods. After wear testing, the hardness and fracture toughness of the ceramic surfaces were determined, and scanning electron photomicrographs were made using representative ceramic and enamel specimens from each group. Enamel wear areas, abrasion and attrition depths, hardness, and fracture toughness values were subjected to analysis of variance and Tukey-Kramer post hoc tests to determine significant differences., Results: Enamel wear was not significantly different for low-fusing and conventional porcelains (p =.29). The wear of conventional and low-fusing ceramic substrates was also not significantly different (p =.79). However, depth of porcelain wear caused by attrition was in general significantly greater than abrasive wear (p =.0004). Although no significant differences were found in the measured porcelain hardness values (p =.08), 1 conventional porcelain exhibited fracture toughness significantly greater than 1 low-fusing porcelain (p <.01)., Conclusions: No differences in wear patterns were noted among low-fusing compared with conventional metal-ceramic porcelains, but static loading resulted in significantly greater attrition compared with the observed sliding abrasive wear. J Prosthodont 2001;10:8-15., (Copyright 2001 by The American College of Prosthodontists)

Purpose: The objective of this study was to determine the severity, distribution, and correlates of tooth wear in a sample of Mexican-American and European-American adults drawn from a community-based longitudinal aging study on oral health., Materials and Methods: The maxillary teeth of 71 subjects enrolled in a longitudinal aging study were assessed using a previously introduced five-point (0 to 4) ordinal scoring system in which each tooth is given a score describing the severity of wear. The tooth wear scores were compared with data concerning demographic factors, functional/parafunctional habits, soft drink consumption, and bite force measurements to determine specific correlates of tooth wear., Results: The mean wear score for all teeth was 1.50 on the five-point scale. There was a significant difference between the mean wear score of anterior teeth (1.85) and posterior teeth (1.17). Bivariate analyses detected a moderate degree of correlation between maxillary tooth wear and age and bite force. Maxillary tooth wear was significantly greater in males and in subjects with reported teeth clenching/grinding. Multivariate analyses revealed that age, gender, bite force, self-reported teeth clenching/grinding, and number of daily meals/snacks had significant correlations with maxillary tooth wear., Conclusion: The overall severity of maxillary tooth wear in this sample of Mexican-American and European-American adults was low, with anterior teeth having a greater degree of wear than posterior teeth. Age, gender, bite force, teeth clenching/grinding, and number of daily meals/snacks are potential factors that may have contributed to tooth wear in the study sample.

Objectives: To establish whether partial recording can be used for the measurement and reporting of tooth wear data in samples of adult populations, whilst maintaining the usefulness of the index., Methods: Using whole mouth coronal tooth wear data from a large random population sample of 1200 dentate older adults in England, several different partial recording systems were investigated to establish which teeth would maintain a high level of sensitivity for the most economic use of codes and index teeth. Tooth wear data were recorded on a surface-by-surface basis on all teeth in the sample using the tooth wear index., Results: Five different partial mouth recording systems were assessed, including half-mouth scoring, assessment of just upper or just lower anterior teeth, assessment of all anterior teeth and use of six index teeth. The 12 anterior teeth were the ones most often affected by moderate or severe wear, and when all 12 teeth were used as the index teeth few wear cases were missed, and all the most extensive and severe cases of coronal wear were classified as having some wear. A limited index of only six anterior teeth (three uppers and three lowers) was almost as sensitive, but allowed less flexibility when reporting the extent of coronal wear. Other systems for partial recording were less sensitive., Conclusions: Partial recording using six or 12 anterior teeth is appropriate for measuring and reporting tooth wear data in large population surveys.

Statement of Problem: Confusion about the relationship of occlusion to temporomandibular disorders (TMD) persists., Purpose: This study attempted to identify occlusal and attrition factors plus age that would characterize asymptomatic normal female subjects., Methods and Material: A total of 124 female patients with intracapsular TMD were compared with 47 asymptomatic female controls for associations to 9 occlusal factors, 3 attrition severity measures, and age using classification tree, multiple stepwise logistic regression, and univariate analyses. Models were tested for accuracy (sensitivity and specificity) and total contribution to the variance., Results: The classification tree model had 4 terminal nodes that used only anterior attrition and age. "Normals" were mainly characterized by low attrition levels, whereas patients had higher attrition and tended to be younger. The tree model was only moderately useful (sensitivity 63%, specificity 94%) in predicting normals. The logistic regression model incorporated unilateral posterior crossbite and mediotrusive attrition severity in addition to the 2 factors in the tree, but was slightly less accurate than the tree (sensitivity 51%, specificity 90%). When only occlusal factors were considered in the analysis, normals were additionally characterized by a lack of anterior open bite, smaller overjet, and smaller RCP-ICP slides. The log likelihood accounted for was similar for both the tree (pseudo R(2) = 29.38%; mean deviance = 0.95) and the multiple logistic regression (Cox Snell R(2) = 30.3%, mean deviance = 0.84) models., Conclusion: The occlusal and attrition factors studied were only moderately useful in differentiating normals from TMD patients.

Tooth wear rarely occurs as a result of one factor alone. Non-carious loss of tooth tissue can be subdivided into attrition, demastication, abrasion, fractionation, and erosion. Clinically, the tooth tissue loss may result from any combination of these types of wear. The first essential principle in the management of tooth wear is, as far as possible, to remove the cause. Secondly, restoration may be indicated.

An overview of tooth wear, i.e. of non-carious destructive processes affecting the teeth including abrasion, demastication, attrition, abfraction, resorption and erosion is presented. The nomenclature and classification of dental erosion commonly used in the dental literature are summarized. They are based on etiology (extrinsic, intrinsic, idiopathic), on clinical severity (Classes I to III), on pathogenetic activity (manifest, latent) or on localization (perimolysis). Interactions between erosion and abrasion, demastication, attrition, and abfraction as well as caries and low salivary flow rate are highlighted.