Original Articles
Frequency of Bolton tooth-size discrepancies among orthodontic patients

https://doi.org/10.1016/S0889-5406(96)70083-5Get rights and content

Abstract

The purpose of this study was to determine the percentage of orthodontic patients who present with an interarch tooth-size discrepancy likely to affect treatment planning or results. The Bolton tooth-size discrepancies of 157 patients accepted for treatment in an orthodontic residency program were evaluated for the frequency and the magnitude of deviation from Bolton's mean. Discrepancies outside of 2 SD were considered as potentially significant with regard to treatment planning and treatment results. Although the mean of the sample was nearly identical to that of Bolton's, the range and standard deviation varied considerably with a large percentage of the orthodontic patients having discrepancies outside of Bolton's 2 SD. With such a high frequency of significant discrepancies it would seem prudent to routinely perform a tooth-size analysis and incorporate the findings into orthodontic treatment planning. (Am J Orthod Dentofac Orthop 1996;110:24-7.)

Section snippets

Materials and methods

The data for this study were obtained from records taken at the Ft. Meade Residency Program, where a Bolton tooth-size analysis is performed routinely on all patients accepted into the program. Only records of those patients with permanent dentitions were considered for evaluation to eliminate errors that may be incorporated from the prediction of sizes of unerupted teeth. Those with any significant attrition or those missing any permanent teeth other than second or third molars were not

Results

The mean overall “12” ratio for the orthodontic patients was found to be 91.4 (Table I), with a standard deviation of 2.57. The values ranged from a low of 82.8 to a high of 99.4, and the median was 91.3. The standard error of the mean was 0.21 and the coefficient of variation was 2.81%. Of the 157 cases, 21 (13.4%) had overall “12” ratios outside of 2 SD from Bolton's mean (Fig. 1).

. Fort Meade orthodontic cases. Overall “12” ratio: 91.3 = Bolton's mean. 89.4 to 91.2 and 91.4 to 93.2 are within

Discussion

Although the means of the orthodontic patients in this study and those of the Bolton study are nearly identical, the ranges and standard deviations of the orthodontic patients are significantly larger. Similar findings were found by Crosby and Alexander in evaluating orthodontic patients in a civilian practice.7 If those cases with ratios greater than 2 SD away from Bolton's means truly represent a significant discrepancy, then a large percentage of orthodontic patients present with relative

Conclusions

These findings suggest that a large number of patients presenting for orthodontic treatment possess a Bolton tooth-size discrepancy that may influence treatment goals and results. This study found 30.6% of orthodontic patients to have a significant anterior tooth-size discrepancy compared with the 22.9% found by Crosby and Alexander.7 Perhaps the difference may be explained by the patient selection process in a military residency program versus a private practice. Because of limited resources,

References (8)

There are more references available in the full text version of this article.

Cited by (0)

View full text