INTRODUCTION

The desire to improve dentofacial esthetics was the main motivation commonly expressed by orthodontic patients.1–4 This was most evident especially in adults who seek orthognathic surgery.56 Previous studies on the perception of malocclusion found that adults were generally more aware of the arrangement of anterior occlusal traits than buccal segments. The anterior occlusal traits of major concern among adults were anterior crowding, rotations, and overjet.78 Men were generally more satisfied with their dental appearance and less likely to perceive a need for orthodontic treatment to correct their malocclusions than women.9 Stenvik et al10 found that dissatisfaction with dental appearance and desire for treatment decreased with increasing age. Older men did not view having straight teeth to be important when compared with women. The availability of orthodontic services has been shown to affect self-satisfaction of dental appearance and the desire for treatment in young adults.11

Studies on orthodontic treatment need in adults found that up to a third had a moderate to high need for orthodontic treatment.410 A study on US male army recruits using the Treatment Priority Index found that 76.9% of the sample would benefit from treatment, with 16.3% having malocclusions that were severe or handicapping. Recruits with severe handicapping malocclusions were more likely to perceive a need for treatment.12 Bergstrom et al13 found that young adults with minor occlusal irregularities expressed the importance of straight teeth, but adults from urban areas were less tolerable toward malocclusion than those from rural areas. However, there was no difference in the desire for treatment between adults from both areas.

Occlusal indices have been commonly used to objectively assess orthodontic treatment need.14–16 The Index of Orthodontic Treatment Need (IOTN) was developed to identify individuals who would benefit from orthodontic treatment.17 It comprises a dental health component (DHC) and an esthetic component (EC). DHC measures the worst occlusal trait that is potentially damaging to dental tissues. It has 5 grades ranging from 1 (no need for treatment) to 5 (very great need). The qualifier of the component in each grade indicates the occlusal trait that is measured. The EC measures the degree of dental attractiveness ranging from grade 1 (very attractive) to 10 (very unattractive) as an indication for treatment to improve the dental appearance. The IOTN has been shown to be valid and reliable.1819

The fact that malocclusion is not a disease and a patient's decision to undergo orthodontic treatment is elective and influenced by patient and care provider factors.20 Therefore, there is a need to assess the prevailing orthodontic treatment need and demand balance within a community. It is important to determine the extent of this inequity so that high–treatment need individuals who missed the opportunity for treatment at an earlier age can be identified and advised accordingly. Thus, the assessment of treatment need in orthodontically untreated adults could serve as a retrospective indicator of treatment need inequity.

The aims of this study were to determine the level of objective and subjective orthodontic treatment need in orthodontically untreated Asian adult males and their self-perception of dental attractiveness.

MATERIALS AND METHODS

A sample of medically fit male army recruits (n = 339, age 17–22 years) with no history of orthodontic treatment, serial extraction, or craniofacial anomalies participated in this research on a voluntary basis with informed consent. The ethnic distribution of the sample was Chinese (n = 258), Malay (n = 60), and Indian (n = 21). Impressions were taken from all participants for study model fabrication. The participants were asked to rank their own dental attractiveness according to the EC scale of the IOTN. Questionnaires were used to determine the perceived benefits of orthodontic treatment by the participants and their desire for orthodontic treatment in future. All questionnaires were checked for completeness and collected by one investigator at the same session as impression taking. Objective treatment need was assessed by a single examiner who was trained in the use of the IOTN. Study model analysis was performed in accordance to the following protocol:

• Incompetent lips were assumed when an overjet of 3.5– 6.0 mm was present.

• A discrepancy of greater than two mm between retruded contact point and intercuspal position was assumed when crossbites were present and a DHC grade 4c was awarded.

• Masticatory and speech problems were assumed to be present when reverse overjet was present.

Study models with retained primary teeth and no clinical evidence of permanent successors were scored as grade 4 or 5h. Duplicate determination was performed six weeks after the initial scoring on 30 randomly selected study models.

RESULTS

Dental health component

The distribution of DHC grades and qualifiers of the total sample is shown in Table 1. Dental crossbites and displacements were the most commonly encountered occlusal traits in the sample. Figure 1 shows the distribution of DHC scores, with 50.1% of the sample with a definite need for orthodontic treatment (grades 4 and 5), 29.2% with borderline need (grade 3), and 20.7% not requiring treatment (grade 2).

TABLE 1.  Distribution of DHC Scores and Qualifiers of Sample, n = 339^a

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Esthetic component

The distribution of objective EC scores is shown in Figure 2. Dental attractiveness with EC grade 3 had the highest percentage. Definite treatment to improve dental esthetics was found in 29.2% of the sample (EC grades 8, 9, and 10). Borderline need for treatment was found in 28.1% (EC grades 5, 6, and 7), whereas 42.7% did not need treatment to improve the dental appearance.

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Treatment need among ethnic groups

The Malay ethnic group had the highest proportion with definite treatment need based on both DHC (grades 4 and 5) and EC (grades 8–10) when compared with Chinese and Indian groups as shown in Table 2. However, the difference in the level of objective treatment need among the ethnic groups was nonsignificant (P > .05). A higher proportion of subjects had definite objective treatment need based on dental health rather than on dental esthetic reasons within each ethnic group.

TABLE 2.  Distribution of Objective DHC (%) and EC (%) Scores Among Ethnic Groups^a

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Perceived esthetics and desire for and perceived benefits of orthodontic treatment

Only 18.9% of the total sample perceived themselves to have good dental appearance, whereas 36.6% perceived otherwise, and 44.5% were indecisive as shown in Table 3. Slightly more than two-thirds did not consider the need for treatment, whereas only 8.8% thought that they would need treatment. The majority perceived the benefits of orthodontic treatment to be related to the improvement of dental esthetics (76.7%) rather than masticatory and speech function (33.9%).

TABLE 3.  Perceived Dental Esthetics and Treatment Need; Perceived Benefits of Treatment

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Objective vs subjective EC assessment

Table 4 shows the distribution of objective and subjective EC scores. The adult males tend to score themselves on the lower end of the EC scale as compared with objective assessment. There was no correlation between objective and subjective EC scores (P > .05).

TABLE 4.  Objective vs Subjective EC Scores^a*

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DISCUSSION

The results indicated that half the total sample had malocclusions that would require definite orthodontic treatment for dental health reasons (DHC grades 4 and 5). The level of definite objective treatment need in Asian male army recruits was lower as compared with US army recruits.12 However, this comparison could only serve as a guide because a different index was used in that study. Dental crossbites accounted for a high proportion of the Asian males with a definite need for treatment. However, this figure might be slightly elevated as a result of the application of study model protocol for DHC assessment, which assumed all crossbites to be associated with more than two mm of functional shift of the mandible. Almost half of each ethnic subsample had definite treatment need based on dental health reasons. Definite treatment need for esthetic impairment accounted not more than one-third of each ethnic group. There was no significant difference in the level of treatment need among the ethnic groups, although Malay subsample had the greatest proportion of adults with definite treatment need (Table 2).

Twenty-six of the subjects (7.7%) had malocclusions with DHC grades 4a and 5a, which meant that they had overjet greater than six mm. Some of these adults could have been potential candidates for functional therapy in their growing years. Studies on incisor trauma reported that males were more prone than females, and the risk increased with increasing age up to a plateau at about 24 years of age.2122 As such, these individuals could be predisposed to a higher risk of incisor trauma during combat military training. The use of mouth guards during peacetime military training would be appropriate. A small percentage of adults (1.8%) with definite treatment need had reverse overjet of one mm or more (DHC 4m and 5m). It could be inferred that some of these adults would require surgical-orthodontic management to address their treatment need.

Subjects with DHC grade 4h or 5h were assumed to have missing teeth. However, there was a possibility that some of these adults might have impacted permanent successors. This meant that some of the subjects with DHC grade 4h or 5h could have been in the DHC 5i category instead. This could only be confirmed from radiographs that were not within the ethical scope of the study. Nevertheless, subjects with 4h, 5h, and 5i category would still be in the high– treatment need category. A very small percentage had DHC grade 4t (1.2%), which implied that there was a potential for caries and periodontal problems to develop in future at those sites with tipped and partially impacted permanent teeth.

Twenty-nine percentage of the sample had malocclusions (objective EC scores 8–10) that needed treatment from an esthetic viewpoint (Figure 2). This finding revealed that the justification for orthodontic treatment in these adults based on esthetic reason was less warranted than dental health reasons. This disparity could be attributed to the fact that subjects with posterior buccal or lingual crossbites had acceptable dental esthetics. There was no significant correlation (r = 0.027, P > .05) between subjective and objective EC scores (Table 4). Thus, the subjects perceived dental esthetics differently from that of the principle investigator. A high proportion of the adult males (92.3%) ranked themselves in the highly attractive end of the EC scale of grade 4 or less. However, this was not reflected in the questionnaire responses, with only 18.9% perceived themselves to have “a nice looking set of teeth” (Table 3). Perhaps, the subjects were indifferent to the appearance of their dentition as reported in the literature that men generally did not express much dental esthetic concern.9 Recent studies have shown that self-satisfaction with one's own dental appearance and cost of treatment were the two major factors that discouraged individuals from seeking treatment despite the definite need.2324 Only 8.8% of the study sample expressed a need for orthodontic treatment.

Although the results of this study could not be directly applied to the community at large, it did provide sufficient information to justify the need for future studies on orthodontic treatment need in adults to be conducted within the population. The high level of definite objective treatment need based on dental health issues despite the readily available orthodontic care within the community from which the sample was derived warrants further assessment and evaluation of the provision and utilization of orthodontic care in the community.

CONCLUSIONS

A high level of definite objective orthodontic treatment need was found in young Asian adult males. This need was not matched by a similar level of demand for treatment. Dental crossbite was the most common occlusal trait that had contributed to the moderately high level of orthodontic treatment need. There was no difference in the level of orthodontic treatment need among the ethnic groups. There was no significant correlation between objective and subjective assessment of treatment need based on dental esthetics. Objective assessment showed that the justification for orthodontic treatment based on dental health reasons was more evident than esthetic impairment. Future population studies on orthodontic treatment need in adults for both genders are highly recommended.