Frequency of Bolton tooth-size discrepancies among orthodontic patients

doi:10.1016/S0889-5406(96)70083-5

American Journal of Orthodontics and Dentofacial Orthopedics

Volume 110, Issue 1, July 1996, Pages 24-27

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

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Geometric analysis of tooth size among different malocclusion groups in a Hispanic population
2023, American Journal of Orthodontics and Dentofacial Orthopedics
Tooth size ratio is important for optimal dentofacial esthetics, occlusal interdigitation, and postorthodontic treatment stability. Tooth geometry influences tooth size ratio; therefore, tooth size normative data may not be practical across diverse ethnic groups. This study aimed to determine whether there are significant differences in 3-dimensional tooth size among patients in the Hispanic population with Angle Class I, II, and III malocclusions.
The data were collected using intraoral scanned orthodontic study models representing Hispanic orthodontic patients with Angle Class I, II, and III malocclusions. The scanned models were digitized and transferred to a geometric morphometric system. Tooth sizes were determined, quantified, and visualized using contemporary geometric morphometric computational tools.
Tooth size was determined for all teeth and showed a significant difference in 4 out of 28 teeth: Maxillary right first molar, mandibular left second molar, mandibular right first molar and mandibular right second molar. This significant difference was noted among females and affected different malocclusion groups.
Tooth size discrepancy in the Hispanic population varies among malocclusion groups, and the variation is determined by the participant’s gender.
Digital evaluation of Bolton's tooth size discrepancies among different malocclusions categories of Egyptian adolescent orthodontic population: A retrospective study
2022, International Orthodontics
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However, the current results are consistent, in part, with those of Oktay and Ulukaya [16], who observed no significant difference among malocclusion groups in anterior ratio of a Turkish sample, but significant differences for overall ratio that was the highest in the class III group. In disagreement with the present study, other studies reported contradictory results of no noteworthy difference of mean ratios among different malocclusion groups of Portuguese [13], American [27], Italian [42], Sudanese [35], Moroccan [44], Saudi [41], Yemeni [40], and Jordanian [36] samples. Moreover, Basaran et al. [34] and Uysal et al. [23], reported no considerable differences for both ratios in other Turkish samples.
This retrospective investigation aimed to compare Bolton's ratios among different malocclusion groups of Egyptian adolescent orthodontic patients with original Bolton's standards.
Pre-treatment dental casts of 588 Egyptian subjects, 290 males and 298 females with mean age 16.7 ± 2.2 years, were randomly selected and classified into 220 class I (108 males and 112 females), 230 class II (112 males and 118 females), and 138 class III (68 males and 70 females) groups. Mesiodistal widths from first molar to first molar were measured on 3-dimensionally scanned models via software and ratios were calculated. Two-way analysis of variance compared ratios as a function of skeletal classification and gender. Additionally, percentages of significant discrepancy outside 2 standard deviations (SDs) were calculated.
The anterior mean ratio for the total sample were higher (79.4 ± 4.7) and overall mean ratio was lower (90.1 ± 5) than Bolton's standards. The differences between the obtained and standard values were statistically significant (P < 0.001). However, there were no significant differences in either anterior ratio (P = 0.637) or overall ratio (P = 295) regarding gender. Class I cases showed the highest mean anterior ratio of 80 ± 5.7 whereas class II and class III cases had the lowest ratio of 78.5 ± 4.6 and 78.7 ± 3.5, respectively. Concerning overall ratio, class III subjects had the highest ratio of 91.8 ± 2.6 with no substantial distinction from class II cases (90.2 ± 4.7) but was significantly different from class I cases that demonstrated the lowest ratio (89.7 ± 5, P = 0.020). High percentages of patients displayed clinically significant tooth size discrepancies (TSD), exceeding either above or below 2SD of Bolton's values, which were more marked in the anterior ratio. These were 25.2% and 7.4% for anterior ratio and 3.4% and 15.4% for overall ratio.
Tooth size ratios of Egyptian orthodontic patients are generally different than the original Bolton's standards. Patients with class I and class III malocclusions had greater anterior and overall ratios than those with class II malocclusions with no considerable gender differences in either ratio.
Segmental orthognathic surgery for Bolton discrepancy correction
2018, Oral and Maxillofacial Surgery Cases
Citation Excerpt :
Also suggested that genioplasty can be performed when necessary [15,22]. By associating different mandibular movements in a single surgery, it is possible to achieve optimization of surgical time since you have proper planning, experience and professional judgment [24,25]. Mentoplasty and mandibular recoiling conducted in the same surgical session of mandibular constriction and teeth extraction, in this case proved to be fully applicable and favorable as well as patients' satisfaction, even though post-operative recovery was required to be more careful [25].
In association with orthodontic treatment, orthognathic surgery can solve different types of malocclusion amongst dentofacial deformities. Bolton analysis is frequently used to measure the mesiodistal relationship between maxillary and mandibular teeth. When Bolton discrepancy is caused by excessive anteroinferior dental volume, it can be corrected in different ways: selective interproximal dental stripping, changes in buccolingual or mesiodistal angulation of anterior teeth, mandibular incisor extraction or by creating space in the upper jaw between laterals and canines. In more severe Bolton discrepancy cases, however, such corrective maneuvers may not be sufficient to achieve adequate occlusion, turning surgery a suitable treatment choice. The main purpose of this paper is to report a case of a segmental orthognatic surgery to correct Bolton Discrepancy. Mandibular incisor extraction (41) associated with mandibular osteotomy to arch constriction was planned to consequently achieve adequate occlusion and facial harmony. Mandibular fragments were mobilized followed by bilateral sagittal split osteotomy. Constriction was conducted accordingly with bone removed from symphysis and segments were fixed with titanium plates and screws (system 2.0). Dental and skeletal transversal pre-existing discrepancy was corrected suggesting that a meticulous surgical planning associated with adequate dental and skeletal mensuration are mandatory to diagnose and treat Bolton discrepancy. Patients' follow-up showed suitable maxillo-mandibular relationship as well as occlusion stability.
Controversies in Orthognathic Surgery
2017, Oral and Maxillofacial Surgery Clinics of North America
Authors’ response
2017, American Journal of Orthodontics and Dentofacial Orthopedics
Tooth-Size Discrepancies in Patients Requiring Mandibular Advancement Surgery
2016, Journal of Oral and Maxillofacial Surgery
Citation Excerpt :
These patients have a larger mandibular tooth mass with or without a smaller maxillary tooth mass. Freeman et al7 studied a sample of 157 patients who presented for treatment at an orthodontic residency program at Fort Meade, Maryland. Ninety-seven of 157 patients (61.7%) had an anterior ratio greater than the Bolton norm of 77.2.
Numerous studies have shown that tooth size is an important key to ideal occlusion. Bolton (Angle Orthod 28:13, 1958; 48:504, 1962) described a constant ratio between the widths of the upper and lower teeth that must be present to achieve an optimal occlusion. The purpose of this study was to determine the incidence of Bolton discrepancies in patients with Class II malocclusion scheduled for mandibular advancement surgery.
This study included 126 patients (40 male, 86 female) with Class II malocclusion who had at least a mandibular advancement as part of their surgical treatment. The mesiodistal widths of the 6 anterior maxillary and mandibular teeth were measured on preoperative models using a caliper. The measurements were used to compute the anterior Bolton ratio.
Seventy-three of 126 patients (57.9%) were found to have an anterior Bolton ratio greater than the Bolton norm, indicating too much lower tooth mass compared with the upper mass or too little upper tooth mass compared with the lower mass.
Tooth-size discrepancies are common in patients requiring mandibular advancement surgery. This can make it difficult to advance the mandible into a solid Class I relation at the time of surgery. Bolton discrepancies should be considered when planning treatment with presurgical orthodontics. In addition, if necessary, the width of the lower incisors should be decreased or a space distal to the maxillary lateral incisors should be created to allow the establishment of a solid Class I canine occlusion at the time of surgery.

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Original ArticlesFrequency of Bolton tooth-size discrepancies among orthodontic patients