|Year : 2013 | Volume
| Issue : 3 | Page : 110-113
Bolton's intermaxillary tooth size ratios among school going children in Punjab population
Ritu Jindal, Eera Bunger
Department of Pedodontics and Preventive Dentistry, National Dental College and Hospital, Derabassi, Punjab, India
|Date of Submission||16-Jan-2013|
|Date of Acceptance||12-Apr-2013|
|Date of Web Publication||12-Dec-2013|
House No: 279, Urban Estate Phase II, Jalandhar, Punjab
Source of Support: None, Conflict of Interest: None
Background: Incidence of tooth size discrepancy varies between different racial and ethnic groups. Values of tooth size ratios for Punjab population were found to be different when compared to Bolton's Caucasian population.
Materials and Methods: The study sample consisted of study casts of 300 subjects (150 males; 150 females) with an age range of 12-14 years of Punjab population. Alginate Impressions of both arches were taken and dental casts were made. Mesiodistal dimension of each tooth was measured with the help of Digital Vernier Caliper. Further, mean anterior ratio (AR) and overall ratio (OR) was calculated.
Results: AR was 80.87% for males and 78.77% for females. OR was 93.93% in males and 91.58% in females. Statistically significant difference was found between tooth size ratios of Punjab and Caucasian population. Males had larger tooth size ratios as compared to females.
Conclusion: These results suggest that tooth size relationships are population specific. Values specific to specific population should be derived.
Keywords: Bolton ratio, Punjab population, tooth size ratios
|How to cite this article:|
Jindal R, Bunger E. Bolton's intermaxillary tooth size ratios among school going children in Punjab population. Indian J Oral Sci 2013;4:110-3
|How to cite this URL:|
Jindal R, Bunger E. Bolton's intermaxillary tooth size ratios among school going children in Punjab population. Indian J Oral Sci [serial online] 2013 [cited 2019 Nov 20];4:110-3. Available from: http://www.indjos.com/text.asp?2013/4/3/110/122952
| Introduction|| |
The establishment and maintenance of normal occlusion constitute one of the important objectives of orthodontic treatment whether it is preventive, interceptive or corrective.  The availability of information about the size of individual tooth type and groups of teeth in the maxillary and mandibular arches is of importance in clinical orthodontics as it facilitates orthodontic diagnosis and treatment planning.  One of the basic fundamentals with which the orthodontist has to deal in reconstructing the denture is tooth size, specifically the mesiodistal width of the teeth.  Tooth size ratios represent a valid diagnostic tool that allows for prediction of treatment outcomes and may also limit the necessity for diagnostic setups for complex cases.
Al-Omari et al. quoted that according to McLaughlin tooth size should be considered the "seventh key" and without coordination between the sizes of the upper and lower teeth; it would not be possible to obtain a good occlusion during the final stages of orthodontic treatment. This lack of co-ordination is called "tooth size discrepancies" (TSD).  Profit (2007) defined TSD as a disproportion among the size of individual teeth. Without a correct match of the mesiodistal widths of the maxillary and mandibular teeth, it is difficult to obtain an ideal overjet and overbite and a good occlusion during the final stages of orthodontic treatment. 
Pioneer investigation on tooth sizes were conducted by Black in 1902, and Neff in 1949.  Consequently, there have been several studies suggesting methods of defining and measuring tooth size discrepancy, but the best-known study of tooth size disharmony in relation to treatment of malocclusion was by Bolton in 1958. 
There is good evidence that populations differ with respect to interarch tooth size relationships because differences in tooth sizes are not systematic. Because the population and gender differences in maxillary tooth size are not same as the differences in mandibular tooth size, different interarch relationships might be expected. Keeping this in mind, we conducted a study to determine whether the mean overall and anterior ratio (AR) of Punjab Ethnic Population would significantly differ from Caucasian (Bolton) values.
| Materials and Methods|| |
Eleven hundred children were examined from a contemporary population of Punjab which included children studying in the different schools of Punjab and those seen in the out-patient block of Department of Pedodontics and Preventive Dentistry, National Dental College and Hospital, Derabassi, Punjab. All the subjects were diagnosed as having Class I occlusion, with no history of orthodontic treatment. The sample consisted of good quality study casts of both maxillary and mandibular of 300 subjects (150 males and 150 females) with an age range of 12-14 years of Punjabi ethnic population. Written consents were obtained from the parents of all students who underwent examination and/or impression taking.
- Fully erupted dentition up to first permanent molar with no interproximal caries, restorations, attrition, and dental anomaly
- No previous or ongoing orthodontic treatment.
- Clinically evident interproximal dental caries
- An alteration in the number or shape of the teeth that might affect the diameter of the dental arch
- Any oral habit that might influence the dental arch
- Experience of orthodontic treatment prior to the start of examination.
Impressions of both maxillary and mandibular arches were made using standard protocols and according to manufacturers' recommendations using irreversible hydrocolloid; Alginate (Tropicalgin chromatic alginate material; Zhermack). After the complete setting of the alginate, tray was removed from the mouth and poured immediately in Green Dental Stone (Kalstone Dental Stone Class III; Kalabhai, Mumbai). The green dental stone was allowed to set for at least 60 min after which it was gently separated from the impressions. After trimming the models, bases were made with Plaster of Paris (Kaldent Dental plaster class II; Kalabhai, Mumbai) with teeth in occlusion. The study models thus prepared were finished and polished.
The maximum mesiodistal dimension of each tooth on the study models between the mesial and distal contact points on its approximal surfaces was measured with the help of a Digital Vernier Caliper with accuracy of 0.01 mm (Precise, Germany), which was held parallel to the occlusal plane perpendicular to the tooth's long axis.
All tooth size ratios were calculated as explained by Bolton in 1958, 1962. ,
All measurements were carried out by a single examiner to eliminate intraobserver error. For assessment of intraexaminer error; the data collection procedure was repeated by randomly selecting the study models of 40 subjects. The measurements were made by the same examiner at an interval of 1 week. Dahlberg's method  for calculation of error was applied and a range of 0.051-0.183 mm was obtained and considered clinically acceptable.
The data were subsequently processed and analyzed using SPSS statistical software program. Independent t-test was employed to evaluate the results. All tests had 0.05 level of statistical significance. This study was approved by an institutional review board.
| Results|| |
Data were collected from 300 study casts of children ages from 12 years to 14 years. One hundred and fifty subjects were males (50%) and one hundred and fifty were females (150%). Males were found to have larger anterior and overall tooth size ratios as compared to females. Statistical analysis of these results was found to be varying significantly. [Table 1] and [Table 2] show, the comparison of mean, standard deviation of AR, and overall ratio (OR) for Punjab and Caucasian population. Statistical comparison of Punjab population's anterior and overall Bolton ratio with Bolton's proposed mean values of Caucasian population is shown in [Table 3] and [Table 4]. Data comparison between both the sexes is elaborated in [Table 5] and [Table 6]. [Table 7] shows the Mean values for "anterior Bolton ratio" and "overall Bolton ratio" for Male and Female groups of Punjab population.
|Table 3: Comparison of Punjab population's anterior bolton ratio with bolton's proposed mean values of caucasian population |
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|Table 4: Comparison of Punjab population's overall bolton ratio from bolton's proposed mean values of caucasian population |
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|Table 5: Mean, S.D for 'anterior bolton ratio' for male and female groups of Punjab population (12-14 years) |
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|Table 6: Mean, S.D for 'overall bolton ratio' for male and female groups of Punjab population (12-14 years) |
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|Table 7: Mean, S.D for 'anterior bolton ratio' and 'overall bolton ratio' for male and female groups of Punjab population (12-14 years) |
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| Discussion|| |
The tooth size is an important factor to be taken into consideration in orthodontic therapy and examination.  Authors like Lavelle  Santoro et al.  and Bernabé et al.  revealed that the incidence of tooth size discrepancy vary between different racial and population groups. Therefore, different norms and standards need to be developed for different ethnic and racial groups.
So, we conducted a study to determine whether anterior and overall tooth size ratios of Punjab population would significantly differ from Caucasian (Bolton's) values and also to identify possible sex differences in tooth size ratios, if any. In the present investigation, anterior and overall tooth size ratios for the Punjab children were established. The age of the subjects included in our study was 12-14 years, which was relatively young in order to minimize the influence of tooth wear.
The mean AR in our study was found out to be 79.82% ± 3.85 and the OR was 92.75% ± 3.15. On comparing anterior and ORs with Bolton's Caucasian population, it was found that the ratios for our study were higher, which was statistically highly significant and were found similar to other studies. ,,,,,
The difference in these studies could be accounted to the samples involved as Bolton's study used a sample of 55 subjects and our study had a sample size of 300 subjects. Furthermore, the sex composition of Bolton's sample were not specified and it is likely that the selection was biased. 
The AR of 79.82% in this study was comparable to the AR mentioned by Singh and Goyal  as 78% in their study on Punjabi population. However, it was reported to be 79.6% in Whites, 79.3% in Blacks, 80.5% in Hispanics,  78.1% in Dominican Americans,  78.15% in Turkish,  78.32% in Spanish population, 78.09% in Peruvians,  78.99% in Syrian population,  78.0% in Irani-Azari,  78.04% in Nepalese.  In general, the results of the present study were comparable to that of Whites, Blacks,  Syrians,  and Spanish,  population.
The OR of 92.57% in this study was found lower as compared to OR mentioned by Singh and Goyal,  as 96.53% in their study on Punjabi population. It has been mentioned in the literature that OR was observed as 92.30% in Whites, 93.40% in Blacks, 93.1% in Hispanics,  91.3% in Dominican Americans,  91.97% in Spanish population,  92.26% in Syrians,  92.0% in Irani-Azari.  In general, the sample in this study resembled with Whites,  Spanish,  Syrian  population.
In our study, males were found to have statistically larger tooth size ratios as compared to females which was consistent with the results of Lavelle  who also showed similar findings. The values obtained from our study were higher for AR and OR. It depicts mandibular tooth material excess, which further suggests the need for interdental stripping/extractions in the mandibular arch or porcelain veneers and composite build ups in the maxillary arch.
The present study indicated that the values derived from this study and the Bolton's original norms derived from Caucasians do not match hence different values specific to different populations should be derived.
| Conclusion|| |
The following conclusions were drawn from the present study:
- According to Bolton's formulae, mean anterior and ORs derived for the present study were 79.82% ± 3.85 and 92.57% ± 3.15 respectively
- There were significant differences in tooth size discrepancy between males and females
- The anterior as well as ORs for the present sample were greater than Bolton's standards, which was statistically significant and suggests the need for more specific standards for the Punjab population.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]