Evaluation of tooth wear and associated risk factors: A matched case-Control study.

AIM: The aim of this case-control study was to compare the associated risk factors between adults with tooth wear (TW) and age- and sex-matched controls without TW. METHODS: Fifty participants with TW and 50 age- and sex-matched controls participated in this study. A questionnaire was prepared to assess oral healthcare and consumption of erosive food and drinks. All participants completed the diet analysis forms. Saliva characteristics were evaluated with GC Saliva-Check BUFFER test. Examiners measured the TW of case patients, using the TW index. Data were statistically analyzed using Chi-square and Mann-Whitney U-tests (P < 0.05). RESULTS: Individuals in the case group brush their teeth more often (P < 0.05). The difference in erosive food consumption between the case and control groups was significant (P < 0.05). There was no erosive effect of acidic food when consumed as a main meal or a snack (P > 0.05). Although there was no difference between stimulated saliva flow rate and buffering capacity between groups, the difference between the resting saliva flow rates and pH values was significant (P < 0.05). Although some wear was seen on buccal/labial surfaces of teeth, cervical and occlusal/incisal surfaces were scored higher. No TW was observed on palatal/lingual surfaces. The cervical surfaces of mandibular premolars and incisal surfaces of anterior teeth were most affected. CONCLUSION: Of the factors investigated, TW in the case group was correlated with consumption of acidic foods, lower salivary flow rate, and pH.

The Prevalence of Tooth Wear in the Dutch Adult Population.

This study aimed to assess the prevalence of tooth wear in different age groups of the Dutch adult population and to determine this tooth wear distribution by gender, socioeconomic class, and type of teeth. Results were compared with the outcomes of a previous study in a comparable population. As part of a comprehensive investigation of the oral health of the general Dutch adult population in 2013, tooth wear was assessed among 1,125 subjects in the city of 's-Hertogenbosch. The data collected were subjected to stratified analysis by 5 age groups (25-34, 35-44, 45-54, 55-64, and 65-74 years), gender, socioeconomic class, and type of teeth. Tooth wear was assessed using a 5-point ordinal occlusal/incisal grading scale. The number of teeth affected was higher in older age groups. Men showed more tooth wear than women, and subjects with low socioeconomic status (low SES) showed on average higher scores than those with high SES. Tooth wear prevalence found in this study was higher in all age groups than in the previous study. The present study found prevalences of 13% for mild tooth wear and 80% for moderate tooth wear, leading to the conclusion that these are common conditions in the Dutch adult population. Severe tooth wear (prevalence 6%) may however be characterized as rare. A tendency was found for there to be more tooth wear in older age groups, in men as compared with women, in persons with lower SES, and in the present survey as compared with the previous one.

Tooth wear in aging people: an investigation of the prevalence and the influential factors of incisal/occlusal tooth wear in northwest China.

BACKGROUND: The aim of this study was to estimate the prevalence of tooth wear in the aging population of northwest China and to investigate the factors associated with such tooth wear. METHODS: Cross-sectional analytic clinical and questionnaire study was performed in 704 participants who had a mean age of 46.5 ± 0.2 SD and of which 367(52.13%) were males and 337(47.87%) female. These participants were invited when they attended the hospital which located in northwest China for routine oral examination. RESULTS: In the maxilla of the examined patients, the rate of tooth wear varied from 85.51% for molar group, 89.77% for premolar group, 100.0% for canine group to 87.22% for incisor group. In the mandible, the rates were 86.36%, 88.92%, 100.0% and 91.19% for the four groups respectively. Moreover, both the incisor and canine groups of these patients showed median scores of 3, the premolar group showed a median score of 1, and the molar group had a median score of 2. Additionally, multiple factors were considered to contribute to these patterns of tooth wear, especially the habitual consumption of a hard or sour diet (P < 0.05,odds ratio 1.21, 95% confidence intervals 1.04-1.49). CONCLUSIONS: Tooth wear is a common disease in which the anterior teeth exhibit greater wear than posterior teeth. The data support an association between tooth wear and dietary patterns.

Meta-analysis of the prevalence of tooth wear in primary dentition.

AIM: To conduct a meta-analysis of all the studies published in literature over the past three decades on the prevalence of dental erosion in preschool children. MATERIALS AND METHODS: The Pubmed data base revealed only one systematic review on the prevalence of tooth wear in children up to 5 years old. The search included works published from January 1982 to September 2012, using the following combinations of keywords: 1) "dental erosion" AND "children"; 2) "dental erosion in primary dentition"; 3) "dental" AND "attrition" AND "prevalence". The inclusion criteria for papers on tooth wear were the deciduous dentition observed only on the palatal and buccal sides with the distinction of erosion, attrition and abrasion. We took into consideration only randomized control trials. We excluded articles not written in English, case reports, historical and forensic studies, in vitro and in vivo studies. In case of doubt and/or when an abstract was not available, the full text copy of the article was examined. The first search on Pubmed revealed 29 articles, the same found in the study of Kreulen [2010], however we selected only multicentric studies focused on children of age below 5 years old, in which only the primary dentition (D) and only anterior teeth (incisors) were considered. RESULTS: Both forest plot and scatter plot showed the prevalence of dental erosion in primary dentition, and that older children had a more severe dental erosion. CONCLUSION: Dental erosion should be considered a paediatric dentistry pathological entity as well as dental caries, and it can be related to more severe systemic diseases such as Gastroesophageal reflux disease. In addition, taking care of these little patients is important because they might suffer persentiveness, and also pulpal pathology caused by the typical structure of deciduous teeth, where the pulp cavity is wide and close to the dentine and the enamel.

[Optimization of treatment of wedge-shaped tooth defects with hyperesthesia].

Development of tooth wedge-shaped defect leads to a gradual loss of hard tissue and is characterized by pain. Most often patients complain of pain and aesthetic defect that adversely affects the emotional status and quality of life. Search for adequate means and methods of treatment providing increased resistance of dental hard tissues and reducing hyperesthesia is challenging for dentists. Wedge-shaped defect and hyperesthesia as concomitant symptom was found in the city of Ufa in the 5.65 and 63.0% of dental patients, respectively. Analysis of the questionnaires revealed a relationship between the sociological parameters (gender, age, profession) and the patient's quality of life. Improvement of all clinical manifestations was observed in the result of complex treatment.

Epidemiology, aetiology and prevention of tooth wear.

Tooth wear is a commonly reported finding globally; however, many patients are unaware of having tooth wear. Identifying early signs of erosion, abrasion or attrition and determining the risk factors contributing to a patient's tooth wear may help to prevent further loss of enamel and dentine in the future. Appropriate prevention should be instigated, or appropriate referral made to other health professionals, when conditions such as gastroesophageal reflux or eating disorders are suspected. This paper presents the epidemiology and aetiological factors for tooth wear, as well as identifying the common clinical presentations of tooth wear. Patient perspectives on tooth wear and preventive techniques that can be utilised are also discussed.

Alliance of oral hygiene practices and abrasion among urban and rural residents of Central India.

OBJECTIVES: To attain alliance between the oral hygiene practices with prevalence of tooth abrasion among urban and rural adult population of Central India. To plan dental care services in inaccessible areas and to suggest appropriate remedial measures to prevent this avertable and self-inflicted injury of teeth in this cross-sectional study. MATERIALS AND METHODS: A sum of 1045 adult residents both from Urban (529) and rural (516) parts of Bhopal district (Central India) was selected on a random basis. The multistage sampling technique was adopted to ascertain the sample size. In urban area the study population consisted of 240 males, 289 females and 201 males and 315 females in rural area respectively. All residents above 18 years of age from the Bhopal district were included in cross-sectional study. Assessment form comprises of questionnaire and general information on oral hygiene practices, dietary habits and medical history. Abrasion was assessed using diagnostic criteria recommended by Smith and Knight (modified). Chi- square test was used to test associations between categorical variables at 5% level of significance. Regression analysis attempted to define for risk factors causing abrasion. Literature on the prevalence of abrasion is very sparse, so attempt is made to correlate the etiological factors and recommend to prevent tooth wear. RESULTS: Investigation of this cross-sectional study was aggregate of 1045 residences. Result shows high prevalence of abrasion 70.2%. Higher prevalence concomitant with diffident habits related to oral hygiene maintenance was recorded more among rural (76.9%) when compared to urban dwellers (63.7%). Presence of abrasion verifies statistical significance in relation to age, rural urban difference and variations in habit of oral hygiene care. Stated in the present study, avertable and self-inflicted is tooth abrasion, recurrently resulted by the reprehensible brushing method and common use of indigenous material for the maintenance of oral hygiene. CONCLUSION: Shows significant liaisons with the presence of abrasions in relation to Urban and rural dwelling, age, material used and mode of brushing and duration of brushing. Indigenous and course material causes high amount of enamel wear and with the advancement in age abrasion tend to increase. Prevalence of abrasion does not show any gender predilection. Cultural believes, lifestyle and transition reflects in deviating presence of abrasion in populations.

Systematic review of the prevalence of tooth wear in children and adolescents.

Data on the prevalence of tooth wear among children and adolescents are inconsistent. Given the impact of extensive tooth wear for over a lifetime, evidence on the extent is required. The aim was to systematically review the literature on the prevalence of tooth wear in children and adolescents. A PubMed literature search (1980-2008) used the keywords 'tooth' AND 'wear'; 'dental' AND 'attrition' AND 'prevalence'; 'dental' AND 'wear' AND 'prevalence'; 'erosion AND prevalence' AND 'abrasion AND prevalence'. Following exclusion criteria, 29 papers were reviewed using established review methods. There was a total of 45,186 subjects (smallest study 80 and largest study 17,047 subjects) examined from thirteen multiple random clusters, eight multiple convenience clusters and eight convenience clusters. Nine different tooth wear indices were used, but the common denominator among studies was dentin exposure as an indicator of severe wear. Forest plots indicated substantial heterogeneity of the included studies. Prevalence of wear involving dentin ranged from 0 to 82% for deciduous teeth in children up to 7 years; regression analysis showed age and wear to be significantly related. Most of the studies in the permanent dentition showed low dentin exposure, a few reported high prevalence (range 0-54%); age and wear were not related (regression analysis). The results of this systematic review indicate that the prevalence of tooth wear leading to dentin exposure in deciduous teeth increases with age. Increase in wear of permanent teeth with age in adolescents up to 18 years old was not substantiated.

Anterior tooth wear and retention type until 5 years after orthodontic treatment.

OBJECTIVES: To study occlusal wear of anterior teeth in orthodontic patients retained with different retainers until 5 years post-treatment, and to investigate whether type of retention influences occlusal wear. MATERIAL AND METHODS: Orthodontic patients (n=222), aged 15 years maximally at the start of treatment, were followed until 5 years post-treatment. In the maxilla, a retainer bonded on all six teeth or a removable retainer was used; in the mandible, a lingual retainer was bonded on all anterior teeth or on canines only. Dental casts were analyzed before treatment (T(0)), after treatment (T(1)), and 5 years post-treatment (T(5)). Incisal and canine wear were scored by applying a grading scale. Intercanine width, overjet, and overbite were measured with an electronic caliper. Statistics used were: Paired samples t-test for differences over time; Pearson correlation coefficients for associations between wear and retention type; and backward linear regression for influence of retention type on wear. RESULTS: There was an increase in wear during all time periods and for all teeth. From T(0) to T(5) an increase in maxillary intercanine width and maxillary retention had an effect on changes in canine wear. Incisal wear was associated with an increase in upper intercanine width (T(1)-T(5)). For both arches, an increase in maxillary intercanine width during treatment was associated with less progression of canine and incisal wear, but the explained variance was low, 13.4% and 19.3%, respectively. CONCLUSIONS: Retention type and, occasionally, an increase in intercanine width influence anterior teeth wear post-treatment. However, the clinical significance and impact of the examined retention methods on occlusal wear are small.

Oral findings in adults with osteogenesis imperfecta.

This paper describes oral findings in an adult population with osteogenesis imperfecta (OI) in Norway (n=94). All participants underwent a structured interview and an oral examination. Panoramic radiographs were analyzed. The findings were compared with data from other Nordic epidemiological studies. Seventeen individuals (19%) had clinical signs of dentinogenesis imperfecta (DI). Persons with OI had twice as many missing teeth as the general population, and the number of endodontically treated teeth was higher than in the general population. All persons in the study had an acceptable state of tooth tissue loss. Almost all (97%) of the participants in the study group visited a dentist or a dental hygienist regularly. The results of the study indicated a low prevalence of clinical DI compared with previous reported studies. Oral health was not as good in the population with OI when compared with the general population, although daily oral health habits were good and dental visits were regular.

The prevalence of cervical tooth wear in patients with bruxism and other causes of wear.

PURPOSE: The aim of this study was to investigate the prevalence of cervical wear lesions in three groups of patients: bruxists, combined tooth wear, and controls. The hypothesis was that those subjects presenting with bruxism were more likely to develop cervical wear lesions. MATERIALS AND METHODS: Of 119 subjects, 31 were bruxists with a mean age 48.7 years [standard deviation (SD): 11.6]; 22 had combined wear, aged 43.5 years (14.2); and 66 controls aged 44.9 years (17.0). The clinical appearance of the tooth wear was used to recruit subjects to the bruxist and combined tooth wear groups. Control subjects were randomly selected from those attending for routine dental examination at two general dental practices. A tooth wear index (TWI) was used by two trained examiners to record the severity of wear in each group. RESULTS: There was a statistically significant difference between the controls and both the bruxist and combined tooth wear groups for wear on all surfaces (p < or = 0.001). There was no significant difference between the bruxist and the combined tooth wear group for wear on any surface. There was a statistically significant difference between the control group and both the bruxist and the combined tooth wear group for the severity of cervical wear (p < or = 0.005), but no difference between the bruxist and combined tooth wear groups. There was also no statistical difference in the number of cervical lesions between the groups. CONCLUSIONS: In this study, the likely cause of cervical tooth wear was multifactorial.

Irregular tooth wear and longevity in captive wild ruminants: a pilot survey of necropsy reports.

Tooth wear is often suggested as an important factor limiting the life span of free-ranging wildlife. Given the frequent occurrence of poor dental health in captive animals reported in the literature, one would expect tooth health to be a limiting factor in captivity as well. Additionally, it could be assumed that brachydont (browsing) animals are more susceptible to dental health problems than are hypsodont (grazing) animals, given current indications for systematic increased tooth wear in some browsing species. A pilot survey of necropsy reports of adult captive wild ruminants (n = 294, 12 species) in one facility was performed in order to test these hypotheses and to calculate the incidence of irregular tooth wear. The overall incidence of irregular tooth wear was 20%, with a very high proportion of reports that did not mention the teeth at all. In contrast to this study's hypotheses, animals with irregular tooth wear were older than animals that died from other causes, indicating that reaching above-average age was a prerequisite for the development of reported abnormalities in this data set. A grazing species (blackbuck, Antilope cervicapra) was most affected, whereas two browsing species were not affected. Affected species had been regularly fed on sandy soil, whereas browsers had received feeds from racks, indicating that husbandry practices are most important for dental health. There was a high proportion of reported serous fat atrophy in animals with irregular tooth wear, indicating the clinical relevance of the problem. On average, adult individuals of the species investigated reached 41% of the maximum reported life span. Although this number appears low, the lack of comparative data from other facilities does not allow for conclusions on the adequacy of the husbandry practices used.

Signs and symptoms of temporomandibular disorders in Nigerian adult patients with and without occlusal tooth wear.

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.

The prevalence of deciduous tooth wear in six-year-old children and its relationship with potential explanatory factors.

PURPOSE: To evaluate the prevalence and aetiological factors involved with wear of deciduous teeth. MATERIALS AND METHODS: A convenience sample of 356 children (aged 6 years old) was selected at Bauru, SP (Brazil). Clinical examinations were carried out by 1 examiner (Kappa = 0.87), using the Tooth Wear Index (G0-G4). A questionnaire addressing the aetiological factors of tooth wear was applied to parents. RESULTS: Wear on the incisors was diagnosed in 34.8% of children (91.1% G1 and 6.4% G2); 78.1% presented wear in canines (64.7% G1 and 33.1% G2); and 40.7% in molars (89.6% G1 and 9.0% G2). No significant correlation was observed between gastro-oesophageal reflux, toothbrushing habits, or consumption of citrus fruits/soft drinks and the presence of tooth wear for all groups of teeth. The wear showed correlation with the presence of bruxism for canines and with the habit of holding drinks in the mouth before swallowing for incisors (Chi-square test, p < 0.05). CONCLUSIONS: The findings indicate that the wear of incisors could be considered physiological for this age. Further longitudinal studies should be conducted in order to measure the wear in canines and molars in the period close to their replacement by permanent teeth.

The prevalence of dentine hypersensitivity among adult patients attending a Nigerian teaching hospital.

PURPOSE: The purpose of this study was to determine the prevalence of dentine hypersensitivity and to examine some associated factors such as initiating stimuli among adult patients attendingthe Dental Clinic of the Obafemi Awolowo University Teaching Hospital, Ile-Ife, Nigeria. MATERIALS AND METHODS: All consecutive adult patients that presented at the oral diagnosis unit over a period of 13 months, from March 2003 to March 2004, were included in the study. Relevant history, such as nature of the pain, initiating stimulus, frequency of episode, interference with eating, drinking and toothbrushing were taken. Evidence of tooth surface loss was noted. Dentine hypersensitivity was confirmed clinically by the use of air blast from the air-water jet and scratching suspected surfaces with a dental probe. RESULTS: Of the 2165 patients examined, 29 were diagnosed as having dentine hypersensitivity, giving a prevalence figure of 1.34%. The commonest teeth affected were the molars and the commonest initiating factor was cold water. Occlusal surfaces were most affected, followed by cervical surfaces. A male predominance was observed. CONCLUSION: A lower prevalence figure was found in the present study in comparison to earlier reported studies. The prevalence of dentine hypersensitivity is slightly lower in females, with female to male ratio of 1 to 1.42. Dentine hypersensitivity resulted in more severe disturbance when drinking water than when eating or brushing.

Comparative analysis between hard- and soft-filament toothbrushes related to plaque removal and gingival abrasion.

OBJECTIVE: The aim of this split-mouth, examiner-blind study was to compare the dental plaque removal and incidence of gingival abrasion associated with the use of hard- and soft-filament toothbrushes. METHODOLOGY: The test group consisted of 20 non-dental students, mean age 25 years. After a three-day period of plaque accumulation following the use of a disclosing solution, the Quigley-Hein Plaque Index was recorded, while the presence of gingival abrasion was measured from photographs. Pairs of quadrants 1-3 and 2-4 were allocated to supervised brushing with hard- or soft-filament toothbrushes for 30 seconds, limited to the buccal aspects of the teeth. Plaque levels and gingival abrasion were again assessed. Initial and final values of the plaque index and the mean number of abrasions were compared with the Friedman and Wilcoxon tests (p < or = 0.05). RESULTS: Plaque indices were reduced significantly from a baseline of 4.12 in both groups to 1.21 after the use of hard-filament toothbrushes, and to 1.67 after the use of soft-filament toothbrushes. The use of hard-filament toothbrushes resulted in a significantly higher mean number of lesions when compared to the soft-filament toothbrushes; 11.6 and 7.9, respectively (p = 0.018). CONCLUSION: Hard-filament toothbrushes remove more plaque than soft filament brushes, but also cause a higher number of gingival abrasions.

Tooth abrasion in workers exposed to noise in the Montenegrin textile industry.

A cross-sectional study was performed on 225 textile workers from a wool production company in Montenegro to test the hypothesis of a relationship between exposure to intense industrial noise and tooth abrasion. The group exposed to intense noise (104 dB (A) Leq) consisted of 111 weavers (82 males and 29 females), while the control group (81 dB (A) Leq) consisted of 114 blue-collar workers (32 males and 82 females) in preparation departments. A specialist in dental prosthetics clinically examined all the subjects and additionally analyzed tooth statuses on hard plaster models. Gender, age, socioeconomic status and tooth brushing habits of workers were controlled as confounding factors. Significantly high adjusted odds ratios for tooth abrasion of 3.74 (95% CI = 1.42-7.85; p < 0.01) were found among female workers exposed to intense noise in comparison with the control group. The analysis of the subclass of male workers with severe tooth abrasion (grades III-IV) revealed significantly high adjusted odds ratios for tooth abrasion of 5.48 (95% CI = 1.76-14.50; p < 0.01) among the noise exposed group compared to the control group. This study suggests that extremely high levels of occupational noise might be related to tooth abrasion in exposed textile workers.

Tooth surface loss in adult subjects attending a university dental clinic in Trinidad.

OBJECTIVES: To determine the prevalence of tooth surface loss (TSL) in a sample of subjects attending a university dental clinic in Trinidad and to investigate the relationship to tooth brushing, medical history, parafunction and dietary habits. DESIGN: Tooth surface loss was measured clinically by the index used in the 1998 UK, Adult Dental Health Survey. SETTING: Trinidad, West Indies. PARTICIPANTS: Convenience sample of adult subjects attending The University of the West Indies Dental School Polyclinic, Mount Hope. METHODS: A questionnaire was administered and tooth surface loss measured clinically. MAIN OUTCOME MEASURES: mild, moderate and severe tooth surface loss. RESULTS: 155 subjects were examined (mean age 40.6 years) of whom 72% had some degree of TSL with the majority (52%), exhibiting mild, 16% with moderate and 4% with severe TSL. There were associations found between TSL and age (OR=3.14), reflux (OR=1.37), parafunction (OR=1.06), weekly consumption of citrus fruits (OR=1.31) and soft drinks (OR=1.78), daily consumption of alcohol (OR=1.40) and a vegetarian diet (OR=2.79). CONCLUSIONS: Tooth surface loss in this Trinidadian population group appears to be common. Data supports an association between TSL and age, reflux parafunction and certain dietary patterns.

Non-carious tooth conditions in children in the UK, 2003.

BACKGROUND: The 2003 Children's Dental Health Survey is the fourth of the 10-yearly surveys of children's oral health. AIM: To report the prevalence of three non-carious tooth conditions in children in the UK. METHOD: A representative sample of children five, eight, 12 and 15 years of age were examined by calibrated examiners in schools across the UK. The dental examination included accidental damage to incisors, tooth surface loss (TSL) and enamel opacities (age 12 only). A postal questionnaire sought parental and child views on marks on teeth which could not be removed by brushing. RESULTS: The proportion of children sustaining accidental damage to permanent incisors decreased to 11% of 12 and 13% of 15-year-olds, but the majority of accidental damage remained untreated. TSL was found on 53% of five-year-olds and on approximately a third of 12 and 15-year-olds. There was a statistically significant change for TSL on permanent teeth at age 15 where 27% upper incisors had TSL palatally in 1993 compared to 33% in 2003. Thirty-four per cent of 12-year-old children had enamel opacities on one or more of their teeth compared with 36% in 1993. CONCLUSIONS: Tooth surface loss remains a common finding in children in the UK. A large proportion of accidental damage to teeth remains untreated.

Prevalence and side preference for tooth grinding in twins.

BACKGROUND: Estimates of the prevalence of tooth grinding in children range considerably, reflecting different methods of recording. The main aims of this study were to determine the prevalence of tooth grinding in monozygotic (MZ) and dizygotic (DZ) twin pairs by assessing wear faceting on the primary canines, and to compare the faceting on the right and left to determine whether children have a side preference for grinding. METHODS: The sample consisted of 116 MZ twin pairs and 124 dizygous DZ twin pairs, all participants in an ongoing study of dento-facial development at the dental schools in Adelaide and Melbourne. Evidence of wear faceting on primary maxillary and mandibular canine tips was recorded from dental casts, and the side with the larger wear facet recorded. Types of occlusal relationship, handedness, zygosity and gender were also recorded, and associations between variables analysed statistically. RESULTS: Canine tip wear facets were found in 100 per cent of the sample, and grinding was lateralized in 59 per cent of children. MZ twin pairs showed a higher discordance for grinding side preference than DZ twin pairs (33.8 per cent compared with 16.8 per cent), providing evidence of a mirror-imaging effect for grinding side preference. There was no strong evidence that individuals had the same preference for grinding side and handedness, although right-handers (RH) showed a preference for a grinding side more often than non-right-handers (NRH) (63.6 per cent compared with 51.2 per cent), consistent with previous findings that RHs display more cerebral lateralization than NRHs. CONCLUSIONS: Tooth grinding appears to be a universal phenomenon in children and is commonly expressed more on one side than the other. The significantly higher discordance for grinding side preference in MZ twin pairs compared with DZ twin pairs may reflect a mirror-imaging effect in the former. However, at present we have no evidence to suggest that handedness and preferred tooth grinding side are associated.