INTRODUCTION

The perception of beauty is an individual preference that may be influenced by training, cultural and ethnic factors.1–3 Although perception of malocclusion is influenced by aesthetic norms in the society, it is also related to individual psychological factors and norms for dental attractiveness. While dental spacing, especially median diastema, is significantly disapproved in Caucasian cultures,45 it is believed to be a desirable sign of beauty in many African cultures, although there is no published report to support this belief.

The lay person's negative opinion on dental deviations has been demonstrated in several studies.6–9 Shaw et al6 showed that individuals with facial deviations were often subjected to teasing, nicknaming, and social discrimination. In Tanzania, however, it is not uncommon to see people of various ages and varying levels of socioeconomic background smiling, untroubled by very serious occlusal irregularities from the professional point of view.

Generally, decisions concerning orthodontic treatment are made in childhood, and desire for treatment is usually influenced by parental attitudes and values. Peers and parents are the groups usually involved in the initiation of the individual's dissatisfaction with her/his teeth leading to orthodontic treatment demand, with peer group influences being more significant.10 Concern of appearance is a basic motivational factor in seeking orthodontic treatment,1112 although other factors including peer group, social class, sex, and ethnicity have been reported.1013 On the other hand, parents have a major role to play and, therefore, knowledge about their perception of malocclusion is relevant.

The purpose of the study was to investigate and compare the opinions of Tanzanian children and those of their parents on dental attractiveness.

SUBJECTS AND METHODS

Methods

Two separate prestructured questionnaires in a common, locally well-understood and spoken language (Swahili) were given to the children and their parents. Children and their parents completed the questionnaire separately, and the questionnaire for the children was given in their classrooms at their respective schools. Children completed the questionnaire in the presence of one of the investigators (E. A. Mugonzibwa), and they were instructed to ask for clarification whenever they could not understand anything in the questionnaire. Although the instructions were attached to the questionnaire, the investigator repeated the instructions to the pupils just before they completed the questionnaire. The questionnaire for the parents was sent home through their children with an introduction letter in Swahili explaining the purpose of the study and giving instructions for filling-in the questionnaire. The letter also requested that wherever possible, mothers should respond to the questionnaire. If it was not possible for the mother or female guardian to respond to the questionnaire, then the father or male guardian was suggested as an alternative.

For both questionnaires, the first part referred to the demographic characteristics of the respondents. The second part pertained to the respondents' perception of malocclusion and consisted of questions related to 18 intraoral frontal photographs (Figure 1) in response to which they had to give an opinion on the dental attractiveness of the occlusion seen on the photograph. The photographs represented various types of occlusion traits, with the first 10 intraoral photographs representing grade 1–10 of the esthetic component (AC) of the index of orthodontic treatment need (IOTN). The photographs were taken from the archives of slides from orthodontic patients. The AC of the IOTN rates the person's dental attractiveness on a 10-point scale, as illustrated by intraoral photographs.14 Eight intraoral photographs were added to represent malocclusions that are often seen in Tanzania. There were three questions for each photograph (18 × 3 = 54 items), which are listed in Table 1. The first two questions assessed the respondents' perception on the attractiveness of the 18 intraoral photographs. The third question determined the gender preference of the respondents for the occlusion presented on the photographs. A clinical examination of the children was conducted by an investigator (E. A. Mugonzibwa), but the findings are reported elsewhere.15

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TABLE 1. Questions on Dental Attractiveness and Gender Preference and their 5-point Scale Alternatives

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Data processing and analyses were carried out using the statistical package SPSS.16 Paired t-test, and Pearson's and Spearman's correlation coefficients were used to study the influences of the opinion. The fist two questions for the 18 intraoral photographs (18 photographs × 2 questions = 36 items) were subjected to principal component analyses. Frequencies and means for various variables were obtained. Correlations between various variables including factors were calculated.

RESULTS

Demographic characteristics of the respondents are presented in Table 2. About one fifth of the mothers had received primary education or below. Most parents had received secondary education.

TABLE 2. Demographic Characteristics of the Respondents

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A principal component analysis (PCA) was done on the total sample of 386 children, and four factors were generated for the children's opinion on the 18 intraoral photographs that could be clearly interpreted.16 The 36 items (18 photographs × 2 questions) in each sample were reduced to four factors: (1) photographs showing normal occlusion; (2) photographs showing some varying degree of spacing with overbite ≤2 mm or open bite; (3) photographs showing some varying degree of spacing with overbite >2 mm; and (4) photographs showing severe deviations. Also, for the four factors, the sample of 286 parents and their children gave high reliabilities (Crohnbach's alpha ranging from 0.68 to 0.89) for both children and parents as shown in Table 3.

TABLE 3. Description of the Four Factors for the Opinion of the Children and Parents on 18 Intra-oral Photographs

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Table 4 shows the mean scores for the respondents' opinion on the 18 intraoral frontal photographs for the two questions. Both children and parents considered photographs showing severe deviations, including crowding (factor 4), as unattractive. The respondents generally liked the photographs of dentitions showing normal occlusion (factor 1), whereas the means for the opinion on the photographs showing spacing with overbite ≤2 mm or open bite (factor 2) and spacing with overbite >2 mm (factor 3) fell in the middle of the scale, with a tendency toward unattractiveness. For the question, ‘would you be happy if the arrangement of your teeth was like in this photograph,’ the answers were comparable. Whenever there was a significant difference between the opinions of children and parents, children had a larger mean score (ie, less attractive), except for the photographs showing severe deviations, including crowding. The parents' educational status was not correlated with the opinions of both children and parents on the dental attractiveness of the 18 intraoral frontal photographs. However, the opinion was significantly correlated with children's age (P = .02) and sex (P < .0005), with older girls tending to dislike photographs showing severe deviations the most.

TABLE 4. The Mean and Standard Deviation for the Children's and Parents' Opinion on the 18 Intra-oral Frontal Photographs

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Figure 2 shows the respondents' ranking of the first 10 intraoral photographs according to the their answers for the two questions concerning attractiveness. The conventional categories of the AC of the IOTN are given in the middle bar. Only those categories that were ranked differently from the conventional ones by either parents or children are shown by an arrow. Parents' and children's Spearman's rank correlations were r = 0.88 (P < .001) and r = 0.90 (P < .0001), respectively. The collective parents and children's Spearman's rank correlation was r = 0.80 (P < .005). For only two photographs, the ranking by parents or children caused a change of category for treatment need. Photographs 5 and 9 for the children and 7 and 9 for the parents were interchanged between categories of treatment need according to the AC of the IOTN.

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Figures 3 and 4 show the parents' and children's gender preference for the occlusion traits in the 18 intraoral frontal photographs (question 3). Proportions of the respondents who made a gender preference for the photographs varied. About a quarter of the parents and children made a gender preference for photographs 1, 2, 3, 4, 12, 13, 14, and 15 with dentitions showing good occlusion. About 23% of the children and 36% of the parents preferred photographs 4 and 14 with a maxillary central diastema in common for a girl compared with 7%–9% and 5%–6% for a boy, respectively. However, 23%–27% of the children and 33% of the parents did not prefer the same photographs for any sex. Generally, children preferred photographs showing some spacing or central diastema for a girl, whereas parents preferred them for a girl or for both sexes. Respondents ranging from about 10% to 90% of the parents and 23% to 77% of the children had no gender preference for the photographs.

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DISCUSSION

The social background of the respondents was not asked in detail, but Tanzanian public schools generally have children from a wide range of social background. Although the sample is not representative of the whole Tanzanian population for the studied groups of respondents, it gives an overview of the opinion of children and parents on dental attractiveness in the Tanzanian community. The response rate to the questionnaire for the children was excellent, 100%, and most of the returned questionnaires (96.5%) could be used in the data analyses.

The parents' response rate to the questionnaire was acceptable, 73%. The posting of the questionnaires to the parents through their children, the length of the questionnaire, and the voluntary basis of participation may have influenced the response rate of the parents to the questionnaire. In such circumstances, the inactive, busy, and introvert individuals are unlikely to respond. Also, the response to the questionnaire was not anonymous, which might have hindered some respondents from giving detailed information.

This study indicated that both parents and children perceived photographs with severe deviations as the most unattractive. However, the parents scored significantly higher means than the children for the photographs showing severe deviations, indicating that they recognized the definite need for orthodontic treatment more clearly than did their children. The finding supports the role parents may have in shaping the orthodontic norms in the Tanzanian society. Generally, the results are parallel to previous studies using photographs showing severe deviations, including crowding.5817 The respondents perceived photographs 1 and 2 that represented photographs 1 and 2 on the AC scale of the IOTN and showed good occlusion as the most attractive, suggesting that the public seems to agree that the professionally determined normal occlusion is esthetically most pleasing.18–22 In Tanzania, most of the parents' decisions about orthodontic treatment are not based on the advice of dental professionals because there is no organized orthodontic health care program. Although the society as a whole is less exposed to an orthodontic treatment environment, parents seem to have their own subjective judgment as to the contribution of the collective esthetic attributes of the teeth toward attractiveness.

Spacing with or without excessive overbite or open bite fell in the middle of the scale with only a tendency toward unattractiveness. Africans are believed to consider spacing as attractive, but this was not confirmed by our study. On the other hand, prevalence of spacing in this society ranges from 24% to 56%.23–26 Therefore, spacing may be accepted as a society norm because of its high prevalence. With globalization, through television, films, newspapers, and magazines, providing daily reinforcement for global facial stereotypes,2728 people may have a common basis for dental esthetic judgment, regardless of their nationality, age, sex, occupation, or geographical distance.29–31 Because this study was carried out in the urban population, this could have influenced our findings.

In the present study, the ranking of the intraoral photographs by parents and children did not exactly match with the conventional AC scale. Some photographs were interchanged between the borderline and a great need for treatment categories, indicating a difference of opinion between Tanzanian respondents and people in societies at the time when the AC scale of the IOTN was developed with regard to the particular occlusion attractiveness.

Most parents and children made gender preferences for photographs showing normal occlusion. But as soon as the malocclusion was more severe, the proportion of parents and children making no gender preference increased. Photographs showing spacing or central diastema were most preferred for a girl by children, whereas parents preferred them for a girl or for both sexes. Although these findings tend to support the preexisting belief that in African societies central diastema is considered as a sign of beauty, it did not come out strongly. Further research on this issue in the Tanzanian cultural community, involving both urban and rural samples, would be interesting.

CONCLUSIONS

The results indicate that severe deviations, including space deficiency irregularities, were perceived by parents and children as the most unattractive compared with other occlusal anomalies, including open bite, suggesting that from the their point of view, grades 8–10 of the AC scale of the IOTN could be given the first priority when considering an orthodontic treatment policy in Tanzania. Because the societal perception of malocclusion, on which orthodontic treatment standards are based, in the country may vary, more comparative studies should be done to assess the perception of malocclusion in different regions.