Abstract
Background: The prevalence and severity of tooth wear and dental erosion is rising in children and there is no consensus about an index to be employed. Aim: To assess the reliability of an epidemiological scoring system dental wear index (DWI) to measure tooth wear and dental erosive wear. Design: An epidemiological cross-sectional survey was conducted to evaluate and compare tooth wear and dental erosion using the dental wear index and erosion wear index (EWI). The study was conducted with randomised samples of 2,371 children aged between 4 years and 12 years selected from the State of São Paulo, Brazil. Records were used for calculating tooth wear and dental erosion; the incisal edge and canine cusp were excluded. Results: As the schoolchildren’s ages increased the severity of primary tooth wear increased in canines (P = 0.0001, OR = 0.34) and molars (P = 0.0001, OR = 2.47) and erosion wear increased in incisal/occlusal (P = 0.0001, OR = 5.18) and molars (P = 0.0001, OR = 2.47). There was an increased prevalence of wear in the permanent teeth of older schoolchildren, particularly on the incisal/occlusal surfaces (P = 0.0001, OR = 7.03). Conclusion: The prevalence of tooth wear and dental erosion increased as age increased in children. The epidemiological scoring system Dental Wear Index is able to measure both tooth wear and dental erosive wear. This index should be used to monitor the progression of non-carious lesions and to evaluate the levels of disease in the population.
Key words: Tooth wear, tooth erosion, epidemiology, prevalence, cross-sectional studies
INTRODUCTION
Tooth wear has a multifactorial aetiology and is a result of the concurrent action of different mechanisms and factors on the teeth in the oral environment. Dental erosive wear is a mechanism of tooth wear and can be defined as the loss of dental hard tissue owing to the chemical influence of extrinsic and intrinsic acids without bacterial involvement1. Although tooth wear and erosion are not synonymous, difficulty arises when attempting to distinguish acid-eroded teeth from teeth that have become worn as a result of attrition (direct contact tooth-to-tooth wear) and abrasion. There is still no consensus in the literature if epidemiological studies should evaluate only one type of tooth wear or evaluate tooth wear without ranking them according to aetiology.
The prevalence and severity of tooth wear in children and adolescents have been described previously2., 3., 4., 5., 6., 7. and results have shown considerable variation in the level of severity (from 3% to 53% of under 18-year-olds)6., 7., 8.. Epidemiological studies point to a trend towards increasing prevalence of tooth wear between different age cohorts4., 9..
When comparing data from different studies, the challenge is to agree upon the outcome of the conditions as most studies use different clinical tooth wear indices to code wear on the surfaces of teeth10. The purpose of a tooth wear index is to classify and record the severity tooth wear, or type of tooth wear, as dental erosion and study the incidence of their occurrence. Some indices measure tooth wear on every surface of every tooth11, whereas others focus on index surfaces or teeth12. There are a myriad of indices which vary in type of assessment, scale, choice of teeth and others parameters, resulting in non-comparability13. One area of consensus is the recognition of dentine exposure as an indicator for substantial loss of tooth tissue. The exposure of dentine in permanent teeth at a young age is a dramatic finding6.
In epidemiological surveys, the decayed, missing, filled teeth (DMFT)14 index was proposed for detection of dental caries. This index adopts letters and numbers to separate the primary and permanent teeth and is used for different age groups ranging from children to older persons. It has been accepted not only by academics, but also in broad epidemiological surveys all over the world.
For tooth wear and erosive wear, there is no worldwide index to apply in epidemiological surveys.
The Dental Wear Index (DWI)4 has therefore been designed to provide a simple scoring system that can be used with the diagnostic criteria of all existing indices, with the aim of transferring their results to record the most severely affected surface and using the cumulative score to guide management of the condition.
There is no consensus about whether to adopt incisal or occlusal surfaces for evaluating dental wear because of the possibility that the subject may have physiological and/or pathological wear in relation to age15.
Thus, the aim of this study was to assess the reliability of the DWI in measuring tooth wear and dental erosive wear.
MATERIAL AND METHODS
This article describes the results of a cross-sectional observational study stratified cluster sample design. The study was conducted with randomised samples of 2,371 children aged between 4 years and 12 years selected from the State of São Paulo, Brazil.
Ethical considerations
This research was approved by the Institutional Review Board of Bauru School of Dentistry, University of São Paulo (Proc. 072/2008, 112/2008 and 116/2009) and conducted in full accordance with the World Medical Association Declaration of Helsinki. For ethical reasons, written permission from children’s parents was obtained before starting the clinical examinations. The parents and children were provided with information on the study, in addition to details of the aim of procedures and expected use of the data, in order to obtain positive consent to participate in this study.
Sample structure
In the sample calculation, an estimated wear prevalence of around 30% of the base population and error of ± 5% (based on information in Sales-Peres et al.4) and a mean 26% of tooth wear for a gap error of ± 0.6 (P < 0.05) were adopted.
Three cities were geographically divided into five regions to compile the sample. The sample was randomly selected using a two-stage stratified cluster sampling approach. The first stage was the random selection of 15 schools in the five regions. The second stage was the random selection of classrooms within the schools. The inclusion criteria were: children aged 4–6 years or 7–10 years or 12 years, enrolled in the schools selected and studying in the classroom selected, and parental consent. Exclusion criteria were the children or the parents not authorising participation in the epidemiological survey. Two schools from the same city had an insufficient sample. Thus, 17 schools were involved in this study to obtain the sample.
The sample comprised 2,371 students. The sample size was stratified by age: 4–6-year-old (n = 655), 7–10-year-olds (n = 1,160) and 12-year-olds (n = 556). The 7–10-year-old age group had more subjects because in this group, primary and permanent teeth are present simultaneously.
Process calibration
Training and calibration exercises for all examiners took place over a 6-month period before the main survey and involved training on cast models, photographs and subjects. The calibration process comprised three steps: (1) examiners’ were trained to learn the index; (2) kappa calculation to analyse agreement and to create matrices; (3) some examiners performed new examinations and a gold standard for examiners was established to evaluate accuracy.
Four examiners performed theoretical and practical activities with discussions on diagnosis criteria of tooth wear [DWI and erosion wear index (EWI)]. For each 10 children evaluated, one child was re-examined to calculate the kappa; thus at the end of survey 10% of the sample was re-examined16. As rule of thumb values of kappa from 0.40 to 0.59 are considered moderate, 0.60 to 0.79 substantial and 0.80 outstanding16. The kappa values need to be at least 0.6 and most often higher than 0.7, before claiming a good level of agreement.
Examination methodology
Examinations were carried out in schoolrooms by trained examiners under standardised conditions, with the children in sitting position. The teeth were dried using equipment with an air syringe and were examined with a disposable mouth mirror and Community Periodontal Index probe (‘ball point’) under natural lighting. All cross-infection control measures were adopted and clinical equipment used in accordance with the World Health Organisation (WHO) guidelines for epidemiological studies14.
An assessment of DWI and EWI were made according to diagnostic criteria proposed by Sales Peres et al. (2008)4. The DWI evaluates all teeth, divided into three surfaces (buccal, incisal/occlusal and lingual surfaces). The surfaces were scored as ‘a’ or ‘0’ (normal), ‘b’ or ‘1’ (enamel involvement), ‘c’ or ‘2’ (exposed dentine), ‘d’ or ‘3’ (secondary dentine or pulp exposure), ‘e’ or ‘4’ (restored owing tooth wear) and ‘–’ or ‘9’ (could not be assessed) for primary and permanent teeth, respectively. Buccal/facial, incisal/occlusal, and lingual/palatine surfaces were examined and recorded on a specific form. The DWI was developed using to the DMFT to increase the intra- and inter-examiner reproducibility and accuracy4. In contrast, the EWI adopts the same codes and criteria for tooth loss and excludes the incisal edge of the 12 anterior teeth15.
Statistical analysis
Descriptive statistics was performed. Univariate analyses using the chi-square test (χ2) were performed to test the influence of independent variables (ages or gender) on dependent variables (dental wear in primary or permanent teeth). Tooth wear or erosive wear data were dichotomised between genders or ages (for primary teeth the ages were divided into 4–6-year-olds and 7–10-year-olds, and permanent teeth were divided into 7–8-year-olds and 9–12-year-olds). A t-test for dependent sample was used to evaluate differences between DWI and EWI (tooth wear in primary or permanent teeth). All statistical analyses were performed using the Statistical program statistica 7.0 (Statsoft, Inc. Tulsa, OK, USA) at 5% significance level.
RESULTS
For dental wear, intra-examiner reliability showed a range of kappa values of 0.84 and inter-examiner values above 0.80. These values reflect substantial agreement in the kappa statistic.
The group consisted of 2,371 children, of whom 46.5% were males and 53.5% females. Of these, 1,041 (51.7% of the total of children examined) had at least one tooth showing signs of tooth wear. The proportion of schoolchildren with enamel wear was 57% in permanent teeth. The 4–9-year-old children had more tooth wear with exposure of dentine (64%) and the 10–12-year-old children showed exposure of more enamel.
The prevalence and severity of dental wear (DWI) was higher in males than in females, mainly on the incisal/occlusal surface (P = 0.000) and on the primary canines (P = 0.034) and molars (P = 0.001) (Table 1). The prevalence and severity of dental erosion (EWI) was higher on the buccal/facial surface (P = 0.033), occlusal surface (P = 0.002) and primary molars (P = 0.001) in males (Table 2).
Table 1.
Univariate analysis of dental wear using the dental wear index (DWI) according to genders distributing into primary and permanent teeth
| DWI | Group | Univariate analyses | |||
|---|---|---|---|---|---|
| Male | Female | Odds ratio | 95% CI | P | |
| Primary teeth | |||||
| Buccal/facial | |||||
| Enamel | 79 | 104 | 0.3575 | 0.15–0.87 | 0.0338 |
| Dentine | 17 | 8 | |||
| Incisal/occlusal | |||||
| Enamel | 222 | 317 | 0.6898 | 0.56–0.85 | 0.0005* |
| Dentine | 602 | 593 | |||
| Lingual/palatal | |||||
| Enamel | 61 | 55 | 0.8873 | 0.42–1.88 | 0.9039 |
| Dentine | 20 | 16 | |||
| Incisors | |||||
| Enamel | 239 | 267 | 0.7621 | 0.57–1.02 | 0.0830 |
| Dentine | 148 | 126 | |||
| Canines | |||||
| Enamel | 242 | 292 | 0.7944 | 0.64–0.98 | 0.0340* |
| Dentine | 555 | 532 | |||
| Molars | |||||
| Enamel | 424 | 539 | 0.7199 | 0.59–0.87 | 0.0010* |
| Dentine | 377 | 345 | |||
| Permanent Teeth | |||||
| Buccal/facial | |||||
| Enamel | 30 | 52 | – | – | – |
| Dentine | 4 | 0 | |||
| Incisal/occlusal | |||||
| Enamel | 421 | 481 | 1.0563 | 0.63–1.76 | 0.9352 |
| Dentine | 29 | 35 | |||
| Lingual/palatal | |||||
| Enamel | 23 | 27 | 0.4259 | – | 0.9195 |
| Dentine | 1 | 1 | |||
| Incisors | |||||
| Enamel | 372 | 295 | 7.8814 | 2.71–22.90 | 0.0001* |
| Dentine | 4 | 25 | |||
| Canines | |||||
| Enamel | 65 | 116 | 0.8405 | 0.40–1.76 | 0.7887 |
| Dentine | 14 | 21 | |||
| Premolars | |||||
| Enamel | 61 | 94 | 0.6596 | 0.16–2.73 | 0.8357 |
| Dentine | 4 | 4 | |||
| Molars | |||||
| Enamel | 372 | 445 | 1.6719 | 0.50–5.60 | 0.5819 |
| Dentine | 4 | 8 | |||
Significant difference was detected between the genders for the dental tissues (P < 0.05).
Table 2.
Univariate analysis of erosive wear using the erosion wear index (EWI) according to genders distributing into primary and permanent teeth
| EWI | Group | Univariate analyses | |||
|---|---|---|---|---|---|
| Male | Female | Odds ratio | 95% CI | P | |
| Primary teeth | |||||
| Buccal/Facial | |||||
| Enamel | 79 | 104 | 0.3575 | 0.15–0.87 | 0.0338* |
| Dentine | 17 | 8 | |||
| Incisal/occlusal | |||||
| Enamel | 429 | 543 | 0.7200 | 0.60–0.87 | 0.0022* |
| Dentine | 372 | 339 | |||
| Lingual/palatal | |||||
| Enamel | 61 | 55 | 0.8873 | 0.42–1.88 | 0.9039 |
| Dentine | 20 | 16 | |||
| Incisors | |||||
| Enamel | 33 | 27 | 2.4444 | 0.74–8.01 | 0.2253 |
| Dentine | 5 | 10 | |||
| Canines | |||||
| Enamel | 66 | 55 | 0.6316 | 0.27–1.47 | 0.3885 |
| Dentine | 19 | 10 | |||
| Molars | |||||
| Enamel | 424 | 539 | 0.7199 | 0.59–0.87 | 0.0010* |
| Dentine | 377 | 345 | |||
| Permanent Teeth | |||||
| Buccal/facial | |||||
| Enamel | 30 | 52 | – | – | – |
| Dentine | 4 | 0 | |||
| Incisal/occlusal | |||||
| Enamel | 377 | 448 | 1.5428 | 0.56–4.21 | 0.5441 |
| Dentine | 6 | 11 | |||
| Lingual/palatal | |||||
| Enamel | 23 | 27 | 0.8519 | – | 0.5405 |
| Dentine | 1 | 1 | |||
| Incisors | |||||
| Enamel | 26 | 32 | 0.2031 | 0.02–1.93 | 0.2963 |
| Dentine | 4 | 1 | |||
| Canines | |||||
| Enamel | 1 | 2 | 0.0000 | – | 1.0000 |
| Dentine | 1 | 0 | |||
| Premolars | |||||
| Enamel | 61 | 94 | 0.6489 | 0.16–2.69 | 0.8186 |
| Dentine | 4 | 4 | |||
| Molars | |||||
| Enamel | 372 | 448 | 1.6607 | 0.49–5.56 | 0.5897 |
| Dentine | 4 | 8 | |||
Significant difference was detected between the genders for the dental tissues (P < 0.05).
There was significant difference in the primary teeth on the lingual/palatal surfaces (P = 0.025; OR = 1.94; 95% CI = 0.74–5.10), canines (P = 0.0001; OR = 0.34; 95% CI = 0.27–0.44) and molars (P = 0.001; OR = 2.47; 95% CI = 2.01–3.05) for DWI regarding age group. In permanent teeth this difference only was found in the incisal/occlusal surfaces (P = 0.0001; OR = 7.03; 95% CI = 3.43–17.45) (Table 3). For EWI, differences were found in occlusal surfaces (P = 0.001; OR = 5.18; 95%CI = 4–12–6.51) and molars (P = 0.0001; OR = 2.47; 95% CI = 2.01–3.05) (Table 4). There were no significant difference for surfaces and groups of teeth in the permanent teeth (P > 0.05). However, the results showed a tendency for erosive wear to occur in occlusal surfaces (P = 0.058) (Table 4).
Table 3.
Univariate analysis of dental wear using the dental wear index (DWI) according to ages distributing into primary and permanent teeth
| DWI | Group | Univariate analyses | |||
|---|---|---|---|---|---|
| 4–6 | 7–10 | Odds ratio | 95% CI | P | |
| Primary teeth | |||||
| Buccal/facial | |||||
| Enamel | 55 | 104 | 0.8462 | 0.36–2.00 | 0.8716 |
| Dentine | 10 | 16 | |||
| Incisal/occlusal | |||||
| Enamel | 211 | 309 | 1.1438 | 0.93–0.1.41 | 0.2328 |
| Dentine | 440 | 737 | |||
| Lingual/palatal | |||||
| Enamel | 33 | 85 | 1.9412 | 0.74–5.10 | 0.02519 |
| Dentine | 6 | 30 | |||
| Incisors | |||||
| Enamel | 393 | 138 | 1.0822 | 0.78–1.50 | 0.6977 |
| Dentine | 200 | 76 | |||
| Canines | |||||
| Enamel | 243 | 302 | 0.3448 | 0.27–0.44 | 0.0001* |
| Dentine | 399 | 671 | |||
| Molars | |||||
| Enamel | 438 | 493 | 2.4746 | 2.01–3.05 | 0.0001* |
| Dentine | 191 | 532 | |||
| 7–8 | 9–12 | ||||
| Permanent teeth | |||||
| Buccal/facial | |||||
| Enamel | 29 | 54 | 1.6111 | – | 0.8968 |
| Dentine | 1 | 3 | |||
| Incisal/occlusal | |||||
| Enamel | 280 | 828 | 7.0338 | 3.43–17.45 | 0.0001* |
| Dentine | 2 | 83 | |||
| Lingual/palatal | |||||
| Enamel | 11 | 40 | 0.2750 | – | 0.9352 |
| Dentine | 1 | 1 | |||
| Incisors | |||||
| Enamel | 77 | 564 | 6.6897 | 0.91–49.14 | 0.0545 |
| Dentine | 1 | 49 | |||
| Canines | |||||
| Enamel | 3 | 309 | 0.5049 | 0.05–4.95 | 0.9082 |
| Dentine | 1 | 52 | |||
| Premolars | |||||
| Enamel | 5 | 179 | 0.2235 | 0.02–2.14 | 0.6649 |
| Dentine | 1 | 8 | |||
| Molars | |||||
| Enamel | 264 | 580 | 4.5517 | 0.58–35.74 | 0.2102 |
| Dentine | 1 | 10 | |||
Significant difference was detected between the ages for the dental tissues (P < 0.05).
Table 4.
Univariate analysis of erosive wear using the erosion wear index (EWI) according to ages distributing into primary and permanent teeth
| EWI | Group | Univariate analyses | |||
|---|---|---|---|---|---|
| 4–6 | 7–10 | Odds ratio | 95% CI | P | |
| Primary teeth | |||||
| Buccal/facial | |||||
| Enamel | 55 | 104 | 0.8462 | 0.36–2.00 | 0.8716 |
| Dentine | 10 | 16 | |||
| Occlusal | |||||
| Enamel | 438 | 238 | 5.1802 | 4.12–6.51 | 0.0001* |
| Dentine | 189 | 532 | |||
| Lingual/palatal | |||||
| Enamel | 33 | 85 | 1.9412 | 0.74–5.10 | 0.02519 |
| Dentine | 6 | 30 | |||
| Incisors | |||||
| Enamel | 51 | 13 | 3.4327 | 1.05–11.21 | 0.0746 |
| Dentine | 8 | 7 | |||
| Canines | |||||
| Enamel | 56 | 70 | 2.6286 | 1.05–6.57 | 0.0560 |
| Dentine | 7 | 23 | |||
| Molars | |||||
| Enamel | 438 | 493 | 2.4746 | 2.01–3.05 | 0.0001* |
| Dentine | 191 | 532 | |||
| 7–8 | 9–12 | ||||
| Permanent teeth | |||||
| Buccal/Facial | |||||
| Enamel | 29 | 54 | 1.6111 | – | 0.8968 |
| Dentine | 1 | 3 | |||
| Occlusal | |||||
| Enamel | 260 | 607 | 6.8534 | 0.90–51.95 | 0.0588 |
| Dentine | 1 | 16 | |||
| Lingual/palatal | |||||
| Enamel | 11 | 40 | 0.2750 | – | 0.9352 |
| Dentine | 1 | 1 | |||
| Incisors | |||||
| Enamel | 10 | 382 | 1.0995 | 0.14–8.80 | 0.6729 |
| Dentine | 1 | 42 | |||
| Canines | |||||
| Enamel | 0 | 182 | – | – | – |
| Dentine | 1 | 34 | |||
| Premolars | |||||
| Enamel | 5 | 179 | 0.2235 | 0.02–2.14 | 0.6649 |
| Dentine | 1 | 8 | |||
| Molars | |||||
| Enamel | 264 | 580 | 4.5517 | 0.58–35.74 | 0.2102 |
| Dentine | 1 | 10 | |||
Significant difference was detected between the ages for the dental tissues (P < 0.05).
A total number of 974 (40.99%) children were found to have wear-free permanent teeth.
When the DWI was adopted to evaluate dental erosion, the incisal surfaces were excluded to minimise the estimate of this wear. The prevalence and severity of surfaces and types of teeth showed significant differences between the two indices only for canines (P = 0.000) in primary and permanent dentition. The teeth most affected were the canines and molars in primary teeth and occlusal surfaces in permanent teeth.
DISCUSSION
Tooth wear is a progressive phenomenon that affects the dentition throughout life. It has been recognised that tooth wear is a clinical problem that is becoming increasingly important in the population17., 18.. Epidemiological studies have reported an increasing prevalence of tooth wear and general dental practitioners see a greater number of patients seeking treatment with worn dentition18.
The training and calibration exercise are crucial steps in cross-sectional epidemiological surveys, and a kappa test calculated on a tooth-by-tooth basis is an appropriate measurement to test agreement among examiners as regards tooth wear. By comparison of the matrices, the indices allow one to identify the criteria that the examiners found more difficult to learn, whereas the kappa test result does not provide this information.
A systematic review of tooth wear in children and adolescents has indicated that the prevalence of tooth wear leading to the exposure of dentine in deciduous teeth increases with age, while the wear of permanent teeth in adolescents does not correlate with age6. The results of the present study revealed a similar increase with age in primary teeth, reinforcing this finding. Analyses performed among the age groups showed that prevalence and severity increased up to the age of 8 years but showed some reduction in children between the ages of 9 to 10 years old, as a result of tooth exfoliation.
In this study, in permanent teeth, the depth most involved was enamel and in primary teeth it extended into dentine. According to Kreulen et al.6, the combination of the time of exposure and resistance of teeth to wear seems to be dependent on age.
The exposure of dentine may be attributed to different aetiological factors11. The assumption that wear on the surfaces of teeth is exclusively caused by erosion can be erroneous given that toothbrush abrasion can affect the buccal surfaces; however, this is unlikely to happen in teeth that are not affected by erosion19.
Different factors, such as age, gender, malocclusion and bruxism, may be associated with tooth wear. Among children, age was associated with increase in tooth wear as well as male gender. When the two indices, DWI and EWI, were evaluated, statistical analysis showed that according to the DWI index, the primary teeth most affected by tooth wear were canines and molars (P < 0.05). However, according to EWI a significant difference was found in molars (P < 0.05). No significant differences between dental wear and erosive wear were found in the permanent teeth (P > 0.05).
Males had more tooth wear in primary molars and in permanent incisors and more erosive wear in primary molars than did females. A significantly higher proportion of males had exposed dentine compared with females, supporting previous results6., 15.. This could result from males having higher biting forces than females20 and different dietary patterns, and possible non-dietary use of teeth21.
When age was dichotomised (4–6-year-olds and 7–10-year-olds) there were differences between indices in primary occlusal surface (DWI P > 0.05; EWI P < 0.05) and canines (DWI P < 0.05; EWI P = 0.0560). Canines showed a significant difference for age by tooth wear but no difference by erosive wear.
Increase in wear of permanent teeth with age in children up to 18 years old was not substantiated6. The results did not show significant differences in permanent teeth for either analysis (DWI and EWI) in genders or ages. However, it is possible that the permanent dentition did not have sufficient period of exposure to present any wear.
As hypothesised, and in agreement with results of other studies3., 7., a significantly higher prevalence of tooth wear (DWI) was found in males than in females. However, if we evaluate only tooth erosion no difference is found (P > 0.05). Both genders were exposed to several acid products and these could reduce the differences between the genders. Another factor may be bruxism. Bruxism is a destructive habit that may result in tooth wear, which consists of non-functional clenching or grinding of the teeth. Although research on bruxism is extensive, its aetiology remains debatable22.
A recent study reported that a higher prevalence of tooth wear is associated with younger age, male gender, class II malocclusion and the absence of open bite in children17. Class II malocclusion was investigated in two studies using the DWI to identify tooth wear patterns in adolescents. The authors concluded that tooth wear in the malocclusion subjects should not be considered pathological but rather the consequence of different interocclusal arrangements23., 24.. Bruxism has consistently been implicated in the aetiology of tooth wear, and malocclusion has not. Class II shows only different tooth-wear patterns when compared with normal occlusion. Nevertheless, these two factors were not investigated in this study.
The combination of the time of exposure and the resistance of teeth to wear seems to be dependent on age. The DWI is able to present the specific tooth wear in different types of teeth (incisors, canines, pre-molars and molars) and surfaces (buccal/facial, incisal/occlusal, palatine/lingual). If the researcher needs to analyse only erosive wear, he/she can exclude the incisal edge of the 12 anterior teeth.
The first specific factor influencing the prevalence of dental wear in these young age groups cannot be identified; neither can the role of the consumption of acid products in the development of severe wear be defined on the basis of the results of the present study. Considering that children are at risk of suffering tooth structure loss, early diagnosis and appropriate prevention measures can avoid the complicated restorative treatment in the future25.
Another point to infer is the differentiation between what is pathological and what is physiological wear, considering the concept of pathological levels of tooth wear, but in absence of consensus differentiation is subjective. As tooth wear is a progressive phenomenon that affects the dentition throughout life, a lifelong approach to management should be undertaken rather than short-term intervention treatment measures26.
All indices for clinical diagnosis or epidemiological surveys of tooth wear or erosive wear attempt to perform visual assessment of the prevalence and severity of dental wear. Both DWI and EWI are indices that present good reproducibility (kappa > 0.84) and accuracy (sensitivity and specificity). The sensitivity measures the proportion of positives (sick people) that are correctly identified and specificity measures the proportion of negatives that are correctly identified. A specific test has few false positives whereas sensitivity detects a high proportion of true cases and thus reduces the number of false negatives. According to Milosevic27, the indices to diagnose exposed dentine were found to be difficult although highly specific.
The reproducibility between the examiners in this present study indicated fair to perfect concordance. The accuracy of visual diagnosis was found to be good, so the validity of currently used indices is not fully established. Primary and permanent teeth could be assessed simultaneously because of the way in which the records were made (letters and numbers).
The DWI could be a useful instrument for broad epidemiological surveys and is designed to be a simple and transferable scoring system. It covers all types of tooth wear, thus facilitating the evaluation in epidemiological studies, and this index could also be adopted for different kinds of tooth wear according to aetiological factors and the following severity. Thus, efforts should be made to validate it as an international index for the indication of dental wear.
CONCLUSIONS
To conclude, in this study of Brazilian children, tooth wear increases with age, and males had more tooth wear in primary teeth than did females. However, in permanent teeth, no significant difference could be observed between the two genders. Therefore, children should be monitored in the initial stages of tooth wear in order to maintain the tooth surface and prevent the dentine from becoming exposed.
The epidemiological scoring system DWI is able to measure tooth wear and dental erosive wear. This index offers enough sensitivity to be used for monitoring the progression of lesions throughout their course and for differentiation between different levels of severity and types of defect.
Acknowledgements
The authors acknowledge the valuable collaboration of all directors, teachers and schoolchildren involved in this investigation.
Conflict of interest
None declared.
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