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BACKGROUND: The Bolton analysis is one of the commonly used tooth size analysis or diagnostic tools in deriving a treatment plan for orthodontic patients. Many studies have indicated and concluded that normal measurements for one group should not be considered normal for other ethnic groups. The aims and objectives of this study were to investigate the applicability of Bolton's ratios in the orthodontic population of Malaysian main ethnics, Malay, Chinese, and Indians. Comparisons were made in terms of size and distribution of tooth size discrepancy in the Malaysian orthodontic population and the findings were converted in terms of millimeters. METHODS: Hundred fifty pre-orthodontic study casts comprised of 52 Malay, 54 Chinese, and 44 Indian patients were selected. Digital calipers (Fowler Pro-Max) linked to Hamilton Tooth Arch Software were used to measure the tooth width and ratios. Statistical analysis was carried out to test for gender differences (independent t-test), to identify the effects of malocclusion and ethnic groups (Two-way ANOVA), and to compare the means of the current study with Bolton's standards (one sample t-test). RESULTS: This study showed that there was no significant difference between the genders of the sample of each ethnicity. There was no correlation found between ethnic groups and malocclusion classes. There was a significant difference when comparing Bolton values with the Malay sample for both ratios. It was found that more Malay subjects presented with maxillary excess contrary to Chinese and Indians who presented more maxillary deficiency for the anterior and overall ratio. CONCLUSION: There was a significant difference found between the TSD of the three major ethnicities in Malaysia. The Bolton standards can be applied to Malaysian Chinese and Indians but not to Malays orthodontic populations for both anterior and overall ratios. Subsequently, a specific standard should be used for the Malays orthodontic population. It was found that more Malay subjects presented with maxillary excess contrary to Chinese and Indians who presented more maxillary deficiency for the anterior and overall ratio.

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BACKGROUND/PURPOSE: Tooth size discrepancy is one of the causative factors of malocclusion. This study aimed to establish the TDS among various malocclusion classes and normal occlusion subjects in a Southern Saudi population. MATERIALS AND METHODS: The study casts of orthodontic patients from Southern Saudi Arabia (mean age: 19.6 years ± 2.45; n = 120) were randomly selected and grouped into eight equal classes based on Angle's classification and gender. An additional 30 study casts, devoid of malocclusion, having excellent intercuspation and class I occlusion, were grouped into two controls (n = 15) based on gender. The study casts were three-dimensional scanned to measure mesiodistal widths of all the teeth. The calculated anterior ratios (AR) and overall ratio (OR) were statistically analyzed with analysis of variance and t-tests. RESULTS: There were no significant differences in "OR" and "AR" between the genders (P > 0.05) and among the malocclusion and control subgroups (P > 0.05). The mean "OR" (92.01 ± 0.18) and "AR" (78.60 ± 0.27) of the malocclusion group were significantly higher than that of Bolton's ratios (P > 0.05). The "AR" of the control group was significantly higher than Bolton's standards (P = 0.048). However, "OR" was no different (P = 0.105). Malocclusion patients displayed a discrepancy (±2 standard deviation) in "AR" of 22.5% and 'OR' of 6.7% from Bolton's mean (BM). Similarly, the control group displayed a discrepancy in "AR" of 20% and "OR" of 10% from BM. CONCLUSION: The mean "OR" and "AR" of the Southern Saudi population showed no sexual dimorphism and no significant difference among various malocclusion and control subgroups. The "AR" of the malocclusion and control subgroups did not comply with Bolton's standards.

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OBJECTIVES: To establish the overall and anterior Bolton ratio among a sample of Qatari population and to investigate whether there is a difference between males and females, as well as to compare the result obtained by Bolton. MATERIALS AND METHODS: The current study consisted of 100 orthodontic study participants (50 males and 50 females) with different malocclusions and age ranging between 15 and 20 years. An electronic digital caliper was used to measure the mesiodistal tooth width of all maxillary and mandibular permanent teeth except second and third molars. The Student's t-test was used to compare tooth-size ratios between males and females and between the results of the present study and Bolton's result. RESULTS: The anterior and overall ratio in Qatari individuals were 78.6 ± 3.4 and 91.8 ± 3.1, respectively. The tooth size ratios were slightly greater in males than that in females, however, the differences were not statistically significant (P > 0.05). There were no significant differences in the overall ratio between Qatari individuals and Bolton's results (P > 0.05), whereas statistical significant differences were observed in anterior ratio (P = 0.007). CONCLUSIONS: Within the limitation of the limitations of the present study, definite conclusion was difficult to establish. Thus, a further study with a large sample in each malocclusion group is required.

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BACKGROUND: The study of the mesiodistal size, the morphology of teeth and dental arch may play an important role in clinical dentistry, as well as other sciences such as Forensic Dentistry and Anthropology. AIMS: The aims of the present study were to establish tooth-size ratio in Sudanese sample with Class I normal occlusion, to compare the tooth-size ratio between the present study and Bolton's study and between genders. MATERIALS AND METHODS: The sample consisted of dental casts of 60 subjects (30 males and 30 females). Bolton formula was used to compute the overall and anterior ratio. The correlation coefficient between the anterior ratio and overall ratio was tested, and Student's t-test was used to compare tooth-size ratios between males and females, and between the present study and Bolton's result. RESULTS: The results of the overall and anterior ratio was relatively similar to the mean values reported by Bolton, and there were no statistically significant differences between the mean values of the anterior ratio and the overall ratio between males and females. The correlation coefficient was (r = 0.79). CONCLUSIONS: The result obtained was similar to the Caucasian race. However, the reality indicates that the Sudanese population consisted of different racial groups; therefore, the firm conclusion is difficult to draw. Since this sample is not representative for the Sudanese population, hence, a further study with a large sample collected from the different parts of the Sudan is required.

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BACKGROUND: For proper intercuspation, the teeth must be proportional in size. If teeth are mismatched, with unusually large teeth in one arch compared to the other, then an ideal occlusion cannot be attained. This study has been done to determine the prevalence of tooth size discrepancies among orthodontic patients in general and also between different malocclusion groups, sex, and to analyze the change in the degree of severity in Bolton discrepancy before and after the hypothetical premolar extraction. METHODS: The study was carried out on randomly collected 100 pre-treatment dental casts. Tooth size analyses were performed on these pre-treatment models and Mesio distal tooth size ratios were measured as described by Bolton before and after various patterns of hypothetical extraction. RESULT: The results were statistically evaluated using ANOVA and paired samples t-test. 5 out of 100 patients are seen with severe Bolton discrepancy with Bolton values (BV) ranging above and below 2 standard deviation. Statistically insignificant difference is seen between males and females and also between various groups of malocclusion. The difference between the pre-treatment and post extraction BV was found statistically significant for the first premolar extraction and insignificant for others. CONCLUSION: The results of this study indicate a new point of view to the question of which teeth to extract when evaluated for tooth size aspect only.

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UNLABELLED: Regards and Tribute: Late Dr Narender Hasija was a mentor and visionary in the light of knowledge and experience. We pay our regards with deepest gratitude to the departed soul to rest in peace. Bolton's ratios help in estimating overbite, overjet relationships, the effects of contemplated extractions on posterior occlusion, incisor relationships and identification of occlusal misfit produced by tooth size discrepancies. AIM: To determine any difference in tooth size discrepancy in anterior as well as overall ratio in different malocclusions and comparison with Bolton's study. MATERIALS AND METHODS: After measuring the teeth on all 100 patients, Bolton's analysis was performed. Results were compared with Bolton's means and standard deviations. The results were also subjected to statistical analysis. Results show that the mean and standard deviations of ideal occlusion cases are comparable with those Bolton but, when the mean and standard deviation of malocclusion groups are compared with those of Bolton, the values of standard deviation are higher, though the mean is comparable. How to cite this article: Hasija N, Bala M, Goyal V. Estimation of Tooth Size Discrepancies among Different Malocclusion Groups. Int J Clin Pediatr Dent 2014;7(2):82-85.

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OBJECTIVE: To determine the prevalence of tooth size discrepancy (TSD) in a representative orthodontics population, to explore how many millimeters of TSD is clinically significant and to determine the ability of simple visual inspection to detect such a discrepancy. MATERIALS AND METHODS: The sample comprised 150 pretreatment study casts with fully erupted and complete permanent dentitions from first molar to first molar, which were selected randomly from records of the orthodontic patients. The mesiodistal diameters of the teeth were measured at contact points using digital calipers and the Bolton's analysis was carried out on them. Simple visual estimation of Bolton discrepancy was also performed. RESULTS: In the sample group, 24% of the patients had anterior tooth width ratios and 8% had total arch ratios greater than ±2 standard deviation (SD) from Bolton's means. For the anterior analysis, correction greater than ±2 mm was required for 24% of patients in the upper arch or 14% in the lower arch. For the total arch analysis, correction greater than ±2 mm was required for 36% of patients in the upper arch or 32% in the lower arch. CONCLUSION: Bolton's analysis should be routinely performed in all orthodontic patients and the findings should be included in orthodontic treatment planning. 2 mm of the required tooth size correction is an appropriate threshold for clinical significance. Visual estimation of TSD has low sensitivity and specificity. Careful measurement is more frequently required in clinical practice than visual estimation would suggest.

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The presence of proportionate teeth size in either arch is a must to obtain an ideal occlusion with good alignment, ideal overjet, ideal overbite and Class I molar relationship. The above facts made us think and to know if this proportion between maxillary and mandibular teeth existed in artificial teeth also? Hence, a survey is undertaken to study the tooth size relation in commercially available artificial teeth. From the results of the present study it was concluded that the anterior and the overall ratios are slightly varied when compared to the standard Bolton's ratios. On comparison the difference between the study ratios and the standard Bolton's ratios were not statistically significant.

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Maxillary and mandibular anterior dental arches often have the problems of occlusal relation and esthetics by malformations of teeth, congenital missing, et al. Though the clinician usually use the anterior ratio to overcome this problems, he has the limitation of a direct application this ratio to the prediction of anterior occlusal relationship by the change of anterior ratio as dental arch form, intercanine width, segment depth and arch perimeter. So this study examine maxillary and mandibular anterior dental arch forms by least square method using Korean normal occlusion models(man : 20 casts, woman : 20 casts). Maxillary and mandibular anterior dental arches of Korean normal occlusion models are curve fitted to polynomial function, beta function, hyperbolic cosine function in order. And this accuracy of curve fitting is constant regardless of man/woman and maxilla/mandible. The relationships between intercanine width, segment depth, and arch perimeter based on this curve fitted dental arch form are acquired. This relationships will give the prediction of anterior dental arch form and the information of more accurate anterior ratio according to intercanine width.

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