Applicability of Bolton's tooth size ratios to a Japanese orthodontic population

Endo, Toshiya; Shundo, Isao; Abe, Ryota; Ishida, Katsuyuki; Yoshino, Sugako; Shimooka, Shohachi

doi:10.1007/s10266-007-0066-8

Cited by 35 publications

(40 citation statements)

References 16 publications

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“…9,12 The amount of SD from the Bolton mean of any measured ratio and the millimetric amount of maxillary and mandibular corrections are used as indicators of clinically significant tooth-size discrepancy. Several studies defined the ratios outside 2 SDs from the Bolton mean as values indicating clinically significant tooth-size discrepancies, [6][7][8]10,11,[13][14][15] while some other studies defined the ratios outside 1 SD from Bolton mean 11,16 because Bolton 3 suggested that a value greater than 1 SD from his mean indicated a possible treatment need. From a clinical perspective, the actual amount of discrepancy expressed in millimeters provides more useful information on the correction for clinically significant tooth-size discrepancy than the ratio in percentage terms.…”

Section: Introductionmentioning

confidence: 99%

Thresholds for Clinically Significant Tooth-Size Discrepancy

Endo

Uchikura²,

Ishida

et al. 2009

The Angle Orthodontist

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Objective: To determine an appropriate threshold for clinically significant tooth-size discrepancy using both a Bolton standard deviation (SD) definition and a millimetric definition. Materials and Methods: Mesiodistal tooth widths were measured in 250 pretreatment dental casts of patients with Class I, Class II, and Class III malocclusions. The anterior and overall ratios and the required amount of maxillary and mandibular corrections were calculated. The casts were divided into small, normal, and large groups according to the anterior and overall ratios categorized by the Bolton SD definition, and into small, normal, and large groups according to the required amount of maxillary and mandibular corrections expressed in millimeters. Results: The small and large anterior ratio groups which fell under the category of the 2 SD threshold did not always need maxillary or mandibular corrections greater than 2 mm, while the small and large overall ratio groups always needed maxillary and mandibular corrections greater than 2 mm. The small and large maxillary correction groups in the 2 mm threshold category did not always have anterior or overall ratios greater than 2 SDs from the Bolton mean. However, the small and large mandibular correction groups always had anterior ratios greater than 2 SDs and did not always have overall ratios greater than 2 SDs. Conclusions: The tooth-size discrepancies could be better expressed in terms of both percentage and actual amount of millimeters required for correction. The ratios outside 2 SDs from the Bolton mean and the discrepancies requiring more than 2 mm of maxillary and/or mandibular corrections are recommendable as the appropriate thresholds for clinical significance. (Angle Orthod. 2009; 79:740-746.)

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Section: Introductionmentioning

confidence: 99%

Thresholds for Clinically Significant Tooth-Size Discrepancy

Endo

Uchikura²,

Ishida

et al. 2009

The Angle Orthodontist

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“…Similarly, other studies did not report differences in both anterior and overall ratios comparing different populations with Bolton standards 10 . On the other hand, contrasting results were reported by Endo et al 7 (2007), who found anterior and overall ratios from a Japanese population greater than those from Bolton's American population.…”

Section: Discussionmentioning

confidence: 68%

“…The Japanese-Brazilian group showed significantly greater anterior and overall ratios than Bolton standards. Other studies also reported significantly greater anterior ratio 8,7,13,24 and overall ratio 6,13,25 than Bolton standards for different populations.…”

Section: Discussionmentioning

confidence: 82%

“…Despite its importance in the clinical setting to guide the orthodontist in cases with extreme tooth size discrepancies, Bolton's ratios have limitations, since the population and sex proportions of his sample were not specified, which implies potential selection bias 6 . There is evidence in the literature pointing towards ethnic differences in tooth size ratios [6][7][8] . It is reported that people with African ethnic backgrounds have larger teeth than do Japanese and Caucasians 9 .…”

Section: XXmentioning

confidence: 99%

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Applicability of bolton’s tooth size ratios among mediterranean, japanese and japanese-brazilian populations

et al. 2017

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Objective: The aim of this study was to determine if Bolton's tooth size ratios can be applied to Mediterranean, Japanese and Japanese-Brazilian populations. Materials and methods: The sample comprised 90 pairs of dental casts of untreated individuals with normal occlusion, divided into 3 groups according to ethnical characteristics: White (30 Mediterranean descendant subjects, with a mean age of 13.64 years), Japanese (30 subjects with Japanese ancestry, with a mean age of 15.63 years) and Japanese-Brazilian (30 Japanese-Brazilian subjects, with a mean age of 13.96 years). A digital caliper was used to measure the maxillary and mandibular mesiodistal widths from first molar to first molar on each dental cast. The anterior and overall tooth size ratios were calculated. T test was applied for comparisons between Bolton standards and the ethnical groups for anterior and overall ratios. Results: Only the Japanese-Brazilian group showed significantly greater ratios than Bolton standards. Conclusion: It was concluded that Bolton's ratios are not applicable to the Japanese-Brazilian population. Therefore, it is suggested that Bolton's ratios may not be suitable for different populations.

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“…The posterior ratio and overall ratio are also used. Although each of these ratios has been studied extensively for a range of different racial [7][8][9][10] and malocclusion groups, [11][12][13][14][15][16] it is not clear whether their clinical application in these studies was appropriate. To clarify this issue, Tonn specifically analyzed the ratio of the upper and lower premolars.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive intermaxillary tooth width proportion of Bangkok residents

Manopatanakul

Watanawirun

2011

Braz. oral res.

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Proper occlusion depends on the correct width ratio between upper and lower teeth, known as Bolton's ratio. In fact, this ratio can be calculated for each pair of teeth from the central incisor to the first permanent molar. This set of ratios, known as comprehensive cumulative percentage ratios (CPRs), can be used not only to determine which tooth or teeth have a tooth width discrepancy, but can also enable the partial graphical analysis of tooth width discrepancy when there is agenesis of certain permanent teeth. Although CPRs have been calculated for Caucasians, tooth width is known to vary depending on racial origin. Therefore, a test of differences between racial groups should be carried out. If these ratios of the Caucasians and Bangkokians are significantly different, the ratio of the Bangkokians is recommended. The objective of this study was to measure tooth size disproportion for Thai patients and to calculate a corresponding set of CPRs. Thirty-seven pairs of dental models were made from a group of Bangkok residents with normal occlusion. Mesiodistal tooth width was measured for each model. The intra-and inter-examiner measurement errors were ascertained as insignificant (p > 0.05). CPRs were then calculated and compared to those derived from other studies. Ten of thirteen CPRs were significantly different from corresponding values derived from Caucasians. We conclude that tooth width ratios vary between different racial groups, and therefore that these should be calculated specifically for each patient racial group.

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Applicability of Bolton's tooth size ratios to a Japanese orthodontic population

Cited by 35 publications

References 16 publications

Thresholds for Clinically Significant Tooth-Size Discrepancy

Thresholds for Clinically Significant Tooth-Size Discrepancy

Applicability of bolton’s tooth size ratios among mediterranean, japanese and japanese-brazilian populations

Comprehensive intermaxillary tooth width proportion of Bangkok residents

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