American Journal of Orthodontics and Dentofacial Orthopedics
Original ArticlesFrequency of Bolton tooth-size discrepancies among orthodontic patients
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).
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,
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