|Year : 2021 | Volume
| Issue : 2 | Page : 208-213
Applicability of Boston University approach for prediction of mesiodistal width of canines and premolars in the primary schoolchildren of rural Bengaluru: An in vivo study
Richardson V Thomas, Neeti Bajaj
Department of Pedodontics and Preventive Dentistry, Dr. Syamala Reddy Dental College, Hospital and Research Centre, Bengaluru, Karnataka, India
|Date of Submission||20-Feb-2019|
|Date of Decision||20-Sep-2019|
|Date of Acceptance||14-Oct-2019|
|Date of Web Publication||29-Jul-2021|
Dr. Richardson V Thomas
Department of Pedodontics and Preventive Dentistry, Dr. Syamala Reddy Dental College, Hospital and Research Centre, Marathahalli, Bengaluru, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Introduction: Boston University (BU) approach is a method for early prediction of unerupted permanent mandibular teeth widths based on the mesiodistal widths (MDWs) of primary mandibular canines and first molars. The present study was conducted to test the validity of BU approach by comparing it with Tanaka–Johnston (T/J) approach in the contemporary population. Aims and Objective: The aim of the study was to determine the applicability of BU approach for prediction of the MDWs of canines and premolars in the primary schoolchildren of rural Bengaluru. Materials and Methods: The study was conducted in 100 healthy schoolchildren of rural Bengaluru aged between 7 and 11 years. The MDWs of canines and premolars were predicted using both T/J and the considered BU approaches for all the children and were compared. Results: The correlation coefficient showed a statistically significant correlation between the predicted tooth size from the two predicted methods in the upper and lower arches (P < 0.001), with Pearson's correlation coefficient showing the very strong positive relationship (r = 0.7). Significant differences were seen between the mean predicted width of canines and premolars by both the approaches (P < 0.001). Conclusion: In spite of the limitations, we recommend the use of BU approach to predict arch length-tooth material discrepancy at an early age and to get at least an approximate estimation of the required space. We also advocate the necessity of further research on this approach prospectively.
Keywords: Boston University analysis, digital Vernier caliper, mesiodistal width, mixed dentition analysis, prediction, Tanaka–Johnston analysis
|How to cite this article:|
Thomas RV, Bajaj N. Applicability of Boston University approach for prediction of mesiodistal width of canines and premolars in the primary schoolchildren of rural Bengaluru: An in vivo study. J Indian Soc Pedod Prev Dent 2021;39:208-13
|How to cite this URL:|
Thomas RV, Bajaj N. Applicability of Boston University approach for prediction of mesiodistal width of canines and premolars in the primary schoolchildren of rural Bengaluru: An in vivo study. J Indian Soc Pedod Prev Dent [serial online] 2021 [cited 2022 Aug 11];39:208-13. Available from: http://www.jisppd.com/text.asp?2021/39/2/208/322512
| Introduction|| |
It has been believed that a large number of cases of malocclusion start during the mixed dentition stage, which spans an interval from the 6th to the 12th year of life. Many of these developing malocclusions may be reduced in severity or even eliminated entirely by time management. The mixed dentition arch analysis is an important criterion in determining whether the orthodontic treatment plan is going to involve serial extraction, guidance of eruption, space maintenance, space regaining, or just periodic observation of the patient. The determination of the tooth size-arch length discrepancy in the mixed dentition requires an accurate prediction of the mesiodistal widths (MDWs) of the unerupted permanent teeth.
Among the different mixed dentition analysis methods reported in the literature, those based on the regression equations are the most widely used, especially the Moyers' probability tables and the Tanaka and Johnston equations. Tanaka and Johnston (1974) utilized a simple linear regression equation to establish prediction tables. The prediction tables constructed by Tanaka and Johnston were practically identical to those published by Moyers. The size in millimeters of unerupted canines and premolars is predicted by taking half the width of the sum of mandibular incisors and adding 11.0 for the maxillary teeth and 10.5 for the mandibular teeth.
Some of the recent studies have reported that only the use of the sum of lower permanent incisors is not the best predictor. The major drawback of these analyses is applicability only after the eruption of mandibular permanent incisors. Hence, Gianelly in his personal communication proposed a prediction method, i.e., based on the MDWs of primary mandibular canines and first molars with an idea for early prediction of unerupted permanent mandibular teeth widths. This was presented at Boston University (BU), and hence, the method was named as BU approach. Subsequently, two studies have carried out on this approach: one on the Iowa population and the other on the Iraqi population.
Most prediction methods have been developed from studies of the Caucasian population, and it has been reported that these prediction methods were not as accurate when used in other ethnic groups. Since space evaluation is so important in many areas of mixed dentition treatment and major treatment decisions are based on differences involving a very few millimeters, it would be to the advantage of the dentist to use as accurate a method of prediction as possible. Hence, this present study was conducted to test the validity of BU approach by comparing it with Tanaka–Johnston (T/J) approach in the contemporary population.
| Materials and Methods|| |
The study was conducted in 100 (50 boys and 50 girls) healthy randomly selected schoolchildren of rural Bengaluru (east) who reported at the Department of Pedodontics and Preventive Dentistry, Dr. Syamala Reddy Dental College, Bangalore, aged between 7 and 11 years with a mean age of 8.85 ± 1.1 years. The children were subjected to clinical examination at the start of the study, and the medical and dental histories were taken. Impressions of maxillary and mandibular arches will be made using irreversible hydrocolloid, rinsed in running water, disinfected with 2% glutaraldehyde, and poured with dental stone [Figure 1] and [Figure 2]. The maximum MDWs of permanent mandibular incisors and primary maxillary and mandibular canines and first molars will be measured using an electronic digital Vernier caliper (with a resolution of 0.01 mm). The tips of the calipers were precision engineered to facilitate the greatest degree of accuracy [Figure 3].
|Figure 3: Mesiodistal width of teeth measured using a digital Vernier caliper|
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The mesiodistal dimensions of the teeth were obtained by measuring the maximum distance between approximate surfaces of teeth as described by W. S. Hunter and W. R. Priest (1960). Measurements of the mesiodistal diameter of all mandibular and maxillary primary canines and primary first molars and mandibular incisors were made by a single investigator. The MDWs of canines and premolars were predicted using both T/J and the considered BU approaches (described below) for all the children.
- MDWs of permanent maxillary canines and premolars = 11 + 0.5 (sum of MDWs of permanent mandibular incisors)
- MDWs of permanent mandibular canines and premolars = 10.5 + 0.5 (sum of MDWs of permanent mandibular incisors).
Boston University approach
The original approach proposed by Gianelly is as follows: MDWs of permanent mandibular canines and premolars = MDW of primary mandibular canine +2 (MDW of primary mandibular first molar). In the present study, we have extended the above formula by calculating the MDWs of both maxillary and mandibular primary canines and first molars for predicting the permanent tooth dimensions.
Thus, both MDW of primary mandibular canine +2 (MDW of primary mandibular first molar) and MDW of primary maxillary canine +2 (MDW of primary maxillary first molar) were calculated for both the right and left sides, and the obtained values were compared with those obtained through T/J approach.
- Children with the existence of primary maxillary and mandibular canines and first molars and eruption of all permanent mandibular incisors
- The teeth should be in occlusion
- Patients with prior consent from parents and school will be included.
- Those with interproximal caries or restorations, missing or supernumerary teeth, abnormalities in shape or size, and a history of orthodontic treatment
- Congenital craniofacial or dental anomalies
- Medically unfit patients
- Age-related attrition.
The following methods of statistical analysis were performed using the Statistical Package for Social Sciences [SPSS] for Windows, Version 22.0 Released 2013 Armonk, NY: IBM Corp. US. The Student's t-test was used to determine whether there was a statistical difference between the groups in the parameters measured. A paired t-test was performed to determine whether there was a difference between the right and left measurements on the panoramic radiographic measurement. Pearson's correlation coefficients were calculated to determine whether there was any correlation between the T/J approach and the BU approach. In the above test, P < 0.05 was considered to be statistically significant.
| Results|| |
The descriptive statistics for the predicted tooth size with the use of the T/J and BU approaches are presented in [Table 1] and [Table 2], respectively. The Student's t-test indicated that there is no statistically significant difference between males and females (P > 0.5). The correlation coefficient indicated the strength of association between the predicted tooth sizes of T/J and BU approaches. [Table 3] shows a statistically significant correlation between the predicted tooth size from the two predicted methods in the upper arch (P < 0.001), with Pearson's correlation coefficient showing the very strong positive relationship (r = 0.7).
|Table 1: Predicted permanent canine and premolar dimensions using Tanaka Johnston approach|
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|Table 2: Predicted permanent canine and premolar dimensions using Boston University approach|
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|Table 3: Correlations between Tanaka Johnston and Boston University approaches in upper arch|
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[Table 4] shows a significant correlation between the predicted tooth size from the two predicted methods in the lower arch (P < 0.001), with Pearson's correlation coefficient showing the very strong positive relationship (r = 0.8). [Table 5] compares the mean predicted values between T/J and BU approaches. The mean predicted value using T/J approach in the upper arch was 21.7 mm and in the lower arch was 21.2 mm. The BU approach predicted a mean value of 20.2 mm in the upper arch and 20.8 mm in the lower arch. Significant differences were seen between the mean predicted width of canines and premolars by both the approaches (P < 0.001).
|Table 4: Correlations between Tanaka Johnston and Boston University approaches in lower arch|
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|Table no. 5: Difference between Tanaka Johnston vs Boston University approaches|
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| Discussion|| |
The mixed dentition stage is the time of developing occlusion in which permanent and primary teeth are present simultaneously. Pedodontists have traditionally accepted the active supervision of the developing dentition as a major responsibility. A difference of ± 2 mm/arch between the predicted width and the actual width is clinically significant as it affects extraction/space maintenance/space-regaining decisions in patients with mixed dentition cases. Realizing the importance of diagnosing the arch length-to-tooth size discrepancy at an early stage, many investigators have formulated criteria for predicting the size of unerupted permanent teeth, especially canines and premolars. If accurate predictions can be made, while patients are in the deciduous or mixed dentition, clinicians might attempt to intercept any developing malocclusion.
Three methods of prediction have been used radiographic, nonradiographic, and regression equations. In radiographic method, quality of the available radiograph is questionable. In cases of rotation and other faulty positions of the tooth buds, the other methods of prediction contribute to a reasonable approximation than the X-ray method. The Hixon and Oldfather prediction method (1958) as refined by Staley et al. (1980) is considered the most accurate (Irwin et al., 1995), but it is complex and may find it difficult to use.
In the present study, a nonradiographic method of prediction, BU approach was revisited, as the prediction of MDWs of permanent canines and premolars can be accomplished even when the child is in the primary dentition stage. For comparison, T/J approach was considered as it is an acceptable method universally and does not require any specialized armamentarium, such as radiographs or prediction tables. Moreover, T/J approach was the one that was used for comparison in the previous studies on BU method. The study was conducted in 100 healthy schoolchildren of rural Bengaluru (east) with a mean age of 8.85 ± 1.1 years.
Gender differences in the prediction values of the unerupted canines and premolars are well reported, because of the differences in the individual tooth dimensions; boys reported to have larger mesiodistal diameters when compared with girls. In the present study, gender variation was assessed in each prediction approach and between the two approaches. Boys had larger dimensions for all the considered teeth but were statistically not significant. The predicted values obtained through all the considered approaches were larger in boys when compared to girls but were not statistically significant (P > 0.5 and P > 0.7) in T/J and BU approaches, respectively. This was in contrast to the results of the previous studies which may be due to the variation in the population selected.
Pearson's correlation coefficient was assessed between the predicted values of canine and premolar width by T/J and BU approaches. On comparing these predicted values, a very high positive correlation was seen with the correlation coefficients in the range of 0.71–0.85. In the Iowa study, the correlation of actual tooth dimensions with those predicted using T/J method was found to be 0.59, whereas that with BU method was 0.39. In another study on the Iraqi population, there was a 0.17 correlation of T/J approach and 0.22 correlation of BU approach with the original teeth dimensions. In the present study, the children studied were still in mixed dentition, and the study design was cross sectional; hence, we could not compare the predicted values with the original ones.
The mean predicted value using T/J approach in the upper arch was 21.7 mm and in the lower arch was 21.2 mm. The BU approach predicted a mean value of 20.2 mm in the upper arch and 20.8 mm in the lower arch. Significant differences were seen between the mean predicted width of canines and premolars by both the approaches (P < 0.001). The mean predicted values obtained through T/J approach were larger when compared to all the considered BU approaches (by 1.5 mm in the upper arch and 0.4 mm in the lower arch). As we could not compare the predicted values with the original dimensions, we cannot comment on the overestimation or underestimation of the approaches employed. However, T/J method tends to overestimate the actual values, which is in accordance with studies done by Diagne et al., Al-Khadra et al., Schirmer et al., and Lee Chan et al. In Indian studies, Kommineni et al. (2014) gave a similar result.
The T/J approach requires the presence of the mandibular permanent incisors to be completely erupted but does not use deciduous tooth measurements, whereas the BU method requires the presence of the deciduous canines and first molars. As a result, the clinician can use either of the two methods depending on which teeth are available in the mandibular dental arch at the various stages of the dental development. The BU approach can be used when the deciduous canines and first molars are still present, which is an advantage in early prediction and in cases of delayed shedding of the deciduous teeth. It is also seen from the results of this study that the predicted values of BU approach are significantly lower than that of T/J approach, and T/J approach is generally overestimated. Hence, BU approach might provide the predicted values closer to the actual value when compared to T/J approach.
The limitation for using primary dentition analysis is that the changes in arch dimensions, as well as tooth position and inclination that maintain the balance among the various functional and structural demands placed on the face and dentition, are difficult to predict in an early age. Due to this reason, some hesitate to recommend BU approach, but not that it can/cannot predict the tooth size.
| Conclusion|| |
Two nonradiographic methods for predicting the mesiodistal diameter of the unerupted mandibular canines and premolars were compared. Depending on the stage of dental development, i.e., which deciduous and/or permanent teeth are present, the T/J approach can be used when the four mandibular incisors have completely erupted; the BU approach can be used when the deciduous canines and first molars are still present.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]