Bolton Ratios Research Articles

Comparison of Bolton’s Ratios in a Sample of Iraqi and Egyptian Populations

Background: The objective of this study was to investigate the possibility of standardizing the Bolton ratio analysis as a diagnostic measure for both Iraqi and Egyptian orthodontic populations within three Angle' classification groups. Materials and methods: Two hundred forty pretreatment study casts (one hundred twenty of each population) were included in this study and divided into three Angle' classification groups. The mesiodistal crown diameters of all teeth were measured for computing the anterior and total Bolton ratios. Analysis of variance was performed to compare the mean ratios of Bolton analysis as a function of the Angle classification.HSD test was used to specify the classes of malocclusion that have significant differences. Results: No statistically significant differences were determined in the mean values of the anterior ratio among the angle classification groups in both Iraqi and Egyptian populations. No statistically significant differences were determined in the mean values of the overall ratio among the angle classification groups in Iraqi population. While there were statistically significant differences in the mean values of overall ratio among the angle classification groups in Egyptian population. This difference is specified with in class II malocclusion of Egyptian population. Conclusion: Anterior Bolton ratio can be standardized for both Iraqi and Egyptian orthodontic populations. While the overall ratio can be standardized only in class I and III malocclusions of both populations.

Bolton discrepancy among patients with anterior open bite malocclusion

IntroductionSeveral investigators studied Bolton's discrepancy in relation to different types of malocclusions, but no studies were found investigating Bolton's discrepancy in open bite cases. The aim of the present study was mainly to determine tooth size discrepancy in a sample of orthodontic patients with open bite malocclusion and to test any correlation between open bite and anterior, posterior, and overall ratios. MethodEighty-four study models of patients with open bite (42 females and 42 males) and 33 study models of ideal occlusion as control (18 females and 15 males) were selected. The mesiodistal width of upper and lower teeth, excluding second and third molars, was measured using a digital calliper, and the anterior, posterior, and overall ratios were calculated. ResultsThe anterior, posterior, and overall ratios for the open bite Saudi sample was 77.14 (SD 3.27), 104.5 (SD 4.80), and 90.46 (SD 3.90), respectively. The Student's t test showed no significant difference between the open bite and control groups in all ratios. The Pearson correlation coefficient showed no significant correlations between open bite and anterior ratio, total ratio, and posterior ratio. ConclusionEven though the anterior, posterior, and overall ratios are not significantly different from control or Bolton's ratios, open bite cases require a close evaluation of tooth size discrepancy in all anterior, posterior, and total ratios to achieve ideal occlusion.

Effect of premolar extraction on Bolton overall ratio in north Indian population

Introduction: Bolton ratio is considered as seventh key of normal occlusion. Many orthodontic patients have to undergo premolar extractions as a part of treatment. Aims and objectives: The present study was taken up to investigate the effect of premolar extractions on Bolton’s overall ratios in a sample of north Indian population. Materials and methods: Mesiodistal tooth widths were measured on pretreatment dental casts of 200 subjects (100 males and 100 females). The Bolton’s overall ratios were determined before and after hypothetical premolar extractions and the subjects were divided into small, normal, and large overall ratio groups categorized by the Bolton standard deviation definition. Extractions were performed in the following combinations: (1) all first premolars, (2) all second premolars, (3) maxillary first and mandibular second premolars, and (4) maxillary second and mandibular first premolars. Results: The overall ratios decreased in every group after extraction of any combination of premolars. Maximum discrepancy was observed in the extraction of all first premolars and least in second premolars. Statistically significant differences were seen in the extraction pattern amongst males and females. Conclusions: In cases which require premolar extractions, it is mandatory to check if any discrepancy exists between different extraction patterns since the ratios may shift from normal to abnormal or vice versa as it may affect the interdigitation of teeth.

Tooth-Size Discrepancies in Patients Requiring Mandibular Advancement Surgery

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.

Bolton ratio in subjects with normal occlusion and class-I malocclusion

Aim: To verify the presence of Bolton ratios [Overall ratio & Anterior ratio] in Bangladeshi individuals with normal occlusion and class-I malocclusion.
 Methods:The materials comprised 120 pre-treatment study cast [60 male & 60 female aged 13-17 years] ,divided into two groups,first group were selected from the models of 60 students who had normal occlusion without crowding [equal male & female] and second group were selected from 60 patients who had Angle class-I crowding[equal male &famale], applied for orthodontic treatment based on the following criteria –permanent dentition from the 1st right molar to the 1st left molar and no interproximal caries or restorations.Bolton anterior & overallratios were performed for the study casts of the subjects using slide caliper.
 Results: The results showed that there was no significants differences between two groups .Also no significant gender differences were found in Bolton anterior& overall ratios.
 Ban J Orthod & Dentofac Orthop, April 2016; Vol-6 (1-2), P.24-28

Intermaxillary tooth size discrepancy in a Pakistani population: A stereomicroscope versus digital caliper.

Objective:Comprehensive diagnosis and treatment planning are essential in a successful orthodontic practice. The purpose of this study is to determine and compare intermaxillary tooth size discrepancy (IMTSD) using traditional digital caliper (DC) measurement on plaster dental models and stereomicroscopic digital dental models (SM).Materials and Methods:The samples were randomly selected from different states of Pakistan. Total 7168 variables were measured on plaster dental casts (128) and SM digital dental models (128) according to the selection criteria. For IMTSD, the 6 variable measured as for anterior tooth size (maxilla, mandibular), overall tooth size (maxilla, mandibular), Bolton's anterior ratios (BAR), and Bolton's overall ratios (BOR). The independent t-test and ANOVA were used for statistical analyses.Results:Significant sexual disparities in the sum of anterior tooth size and overall tooth size via DC and SM methods. No significant sexual disparities for BAR and BOR. No statistically significant differences were found in BAR and BOR between DC and SM. No significant differences were found on IMTSD ratio among different arch length and arch perimeters groups.Conclusions:Norms were developed based on DC and SM for IMTSD. Sexual disparities were observed in the sum of teeth size. However, no significant differences in BAR and BOR for IMTSD between the two methods.

Outcome of premolar extractions on Bolton's overall ratio and tooth size discrepancies in South India.

Aims and Objectives:Attainment of ideal occlusion is often restricted by disproportionate sizes of individual teeth, which is otherwise termed as tooth size discrepancy (TSD). While extraction of teeth for orthodontic purposes is not uncommon, there is considerable resistance against this school of thought. The extraction of premolars, in particular, received considerable attention because of the potential TSD that could result following the extraction of premolars. The aim of the present study was to identify the consequence of premolar extractions on Bolton's overall ratios in South Indian population.Materials and Methods:One hundred participants were recruited into the study through purposive nonproportionate quota sampling. Pretreatment dental casts of the study participants were measured for mesiodistal tooth widths to determine Bolton's overall ratio before the hypothetical tooth extractions were performed. The hypothetical extractions were executed in four different combinations as follows: (a) Maxillary and mandibular first premolars, (b) maxillary first premolars and mandibular second premolars, (c) maxillary second premolars and mandibular first premolars, and (d) maxillary and mandibular second premolars. Bolton's overall ratios were calculated after the hypothetical tooth extractions were performed. Statistical analysis was done using the Statistical Package for the Social Sciences, version 20 software.Results:It was observed that extractions performed in any of the combinations followed in this study resulted in a decrease of overall Bolton's ratios. However, the discrepancy in tooth size was highest with the extraction of all first premolars, whereas least discrepancy was recorded with all second premolars extraction. It was also found that, based on the combination of teeth chosen for extraction, there was significant difference in Bolton's overall ratios between males and females.Conclusion:In formulating a treatment plan involving premolar extraction, significant tooth size discrepancies could change mutually after extraction.

Accuracy of Bolton analysis measured in laser scanned digital models compared with plaster models (gold standard) and cone-beam computer tomography images.

ObjectiveThe aim of this study was to compare the accuracy of Bolton analysis obtained from digital models scanned with the Ortho Insight three-dimensional (3D) laser scanner system to those obtained from cone-beam computed tomography (CBCT) images and traditional plaster models.MethodsCBCT scans and plaster models were obtained from 50 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner; Bolton ratios were calculated with its software. CBCT scans were imported and analyzed using AVIZO software. Plaster models were measured with a digital caliper. Data were analyzed with descriptive statistics and the intraclass correlation coefficient (ICC).ResultsAnterior and overall Bolton ratios obtained by the three different modalities exhibited excellent agreement (> 0.970). The mean differences between the scanned digital models and physical models and between the CBCT images and scanned digital models for overall Bolton ratios were 0.41 ± 0.305% and 0.45 ± 0.456%, respectively; for anterior Bolton ratios, 0.59 ± 0.520% and 1.01 ± 0.780%, respectively. ICC results showed that intraexaminer error reliability was generally excellent (> 0.858 for all three diagnostic modalities), with < 1.45% discrepancy in the Bolton analysis.ConclusionsLaser scanned digital models are highly accurate compared to physical models and CBCT scans for assessing the spatial relationships of dental arches for orthodontic diagnosis.

Bolton ratio in subjects with normal occlusion and malocclusion

Bolton ratio in subjects with normal occlusion and malocclusion

Is arch form influenced by sagittal molar relationship or Bolton tooth-size discrepancy?

BackgroundOrthodontic patients show high prevalence of tooth-size discrepancy. This study investigates the possible association between arch form, clinically significant tooth-size discrepancy, and sagittal molar relationship.MethodsPretreatment orthodontic casts of 230 Saudi patients were classified into one of three arch form types (tapered, ovoid, and square) using digitally scanned images of the mandibular arches. Bolton ratio was calculated, sagittal molar relationship was defined according to Angle classification, and correlations were analyzed using ANOVA, chi-square, and t-tests.ResultsNo single arch form was significantly more common than the others. Furthermore, no association was observed between the presence of significant Bolton discrepancy and the sagittal molar relationship or arch form. Overall Bolton discrepancy is significantly more prevalent in males.ConclusionsArch form in a Saudi patient group is independent of gender, sagittal molar relationship, and Bolton discrepancy.

Tooth size discrepancy among different malocclusion groups in Sudanese sample

BackgroundMany difficulties encountered during the finishing-phase of orthodontic treatment arise due to lack of intermaxillary tooth-size matching. Bolton ratio is one of the most useful calculations for precise orthodontic diagnosis as it shows whether a correct ratio between dental proportions exists or not. ObjectivesTo determine the mesiodistal tooth width in anterior and overall Bolton ratios in normal occlusion and different malocclusion groups in a Sudanese sample and compare to Bolton's standard. Materials and methodsThe sample consisted of 196 (86 male and 110 female) study models with normal occlusion, Class I, II and III malocclusions, and the age of subject 17–20 years old. Tooth size measurements were performed by electronic digital calipers. Tooth size ratios were analyzed as described by Bolton. The incidence of mesiodistal tooth size discrepancies in the malocclusion groups was analyzed and compared between male and female. The anterior and overall ratios were compared with the ratios Bolton's study. ResultsNo significant difference in the anterior and overall ratios of normal occlusion sample when compared to Bolton's standard. No significant differences were found among gender. ANOVA indicated that no significant difference was determined in the anterior and overall ratios in different malocclusion groups. ConclusionBolton's values can be used for Sudanese population until a large representative sample is studied.

Bolton ratio in a North Indian population with different malocclusions.

Objective:The objective was to evaluate the Bolton ratio in a North Indian population in Lucknow with different malocclusion.Materials and Methods:Totally, 110 study cast [Age: Female (14.2 ± 1.5 years, Male (13.9 ± 2.3 years)] were taken from the patients undergoing orthodontic treatment and Subjects were divided into three groups: Group I (Angle's Class I, n = 40), Group II (Angle's Class II, n = 50) and Group III (Angle's Class III, n = 20) according Angle's classification of malocclusion. The mesiodistal widths of all maxillary and mandibular teeth from right first molar to left first molar were measured with a digital caliper to calculate the Bolton ratio. The readings were then used to compute the anterior and total Bolton ratios. ANOVA and Tukey's test were used for the statistical analysis.Results:A mean total Bolton ratio of 91.36 ± 2.13 and a mean anterior Bolton ratio of 78.14 ± 4.09 were found for the sample, Significantly higher mean anterior tooth ratios were found for Group II (Angle's Class II) patients (P < 0.01). All other ratios were within close range of Bolton's norms.Conclusions:Angle's Class II patients showed a tendency toward wider mesiodistal widths of teeth in the mandibular anterior region or smaller tooth sizes in the maxillary anterior region.

Extraction: A Parameter in Bolton Ratio

Aims: To evaluate extraction as a parameter in determination of Bolton ratio in class II division 1 cases. Materials and Methods: Thirty Class II division 1 cases were selected from the records. Bolton overall ratio was calculated. Hypothetically extraction of four different combinations of premolars was done. These combinations were: Upper first premolar, all first premolars, upper first premolars and lower second premolar, all second premolar. The hypothetical extraction was done by substituting zero in place of the corresponding premolars that were removed. The overall ratios were measured again. Results and Conclusion: (1) Extraction can be considered as a parameter in evaluating Bolton ratio. (2) In upper first premolar extraction Bolton ratio increased. (3) When all first premolar, upper first and lower second premolar, all second premolar were extracted the ratio decreased. (4) In all four first premolar, all second premolar, upper four and lower five premolar extraction can be carried out without much affecting Bolton ratio in class II division 1 cases.

Seventh key of occlusion: Diagnostic significance in different angle′s class I, II and III malocclusions

Introduction: As significant tooth size discrepancies prevent an ideal occlusion being produced at the end of orthodontic treatment, absence of a tooth size discrepancy is the seventh key for an ideal occlusion. Present study aimed to assess diagnostic reliability of Bolton's ratio for different Angle's malocclusion. Materials and Methods: The study models of 144 patients were divided in three groups based on malocclusion.The mesiodistal tooth width from permanent first molar to first molar were measured on the orthodontic study models. The readings were obtained using a digital vernier caliper to the nearest 0.01mm, with the blades of the caliper held perpendicular to the long axis of the tooth. Results: ANOVA showed no significant difference between all groups except between anterior ratio of Class II group. The mean ratio for the Class III sample was significantly greater than Class I and Class II subjects ( P Class I > Class II with significant difference between the Class I and Class II groups. Conclusion: Subjects with Class III group had a significantly greater prevalence of tooth size discrepancies than Class I and Class II group. Statistically significant difference was seen in the anterior ratio between the males and females of Class II malocclusion and no significant difference between other groups.

Comparison of tooth size discrepancy in Angle′s class I and class II malocclusion in Rajasthani population

Aim: The purpose of this study was to compare the tooth size discrepancy according to Bolton ratios and norms between class I and class II malocclusion groups in Rajasthani population. Materials and Methods: A quantitative study was carried out at all dental colleges of Rajasthani. Cross-sectional data were gathered from the study casts of patients undergoing orthodontic treatment at all dental colleges of Rajasthan. 105 out of 150 study casts were filtered based upon the inclusion and exclusion criteria. The mesiodistal widths of all maxillary and mandibular teeth from right first molar to left first molar were calibrated with the use of a manual caliper. The readings were then used to compute the anterior and total Bolton ratios. Results: Significantly higher mean anterior tooth ratios were found for class II ( P Conclusion: Class II patients showed a tendency toward higher mesiodistal widths of teeth in the mandibular anterior region

Digital model as an alternative to plaster model in assessment of space analysis.

Introduction:Digital three-dimensional models are widely used for orthodontic diagnosis. The purpose of this study was to appraise the accuracy of digital models obtained from computer-aided design/computer-aided manufacturing (CAD/CAM) and cone-beam computed tomography (CBCT) for tooth-width measurements and the Bolton analysis.Materials and Methods:Digital models (CAD/CAM, CBCT) and plaster model were made for each of 50 subjects. Tooth-width measurements on the digital models (CAD/CAM, CBCT) were compared with those on the corresponding plaster models. The anterior and overall Bolton ratios were calculated for each participant and for each method. The paired t-test was applied to determine the validity.Results:Tooth-width measurements, anterior, and overall Bolton ratio of digital models of CAD/CAM and CBCT did not differ significantly from those on the plaster models.Conclusion:Hence, both CBCT and CAD/CAM are trustable and promising technique that can replace plaster models due to its overwhelming advantages.

Effect of intermaxillary tooth-size discrepancy on accuracy of prediction equations for mixed dentition space analysis.

Correlation-statistical methods are widely used for prediction of size of unerupted permanent canines and premolars in mixed dentition space analysis. The present study was planned to evaluate the effect of selecting dental study casts with no intermaxillary tooth-size discrepancy on the accuracy of predicting mesiodistal widths (MDWS) of permanent canines and premolars. Bolton ratios were calculated for all the screened study dental casts fulfilling the inclusion criteria. Subjects were divided into two groups. Group A: all subjects with no intermaxillary tooth-size discrepancy within ±2 SD (Standard deviation) of the mean values. Group B: increased percentage of subjects with intermaxillary tooth-size discrepancy beyond ±2 SD (Standard deviation) of the mean values. Linear regression equations were established for both maxilla and mandible in both the groups, with different tooth combinations as independent variables. Validation of best possible regression equations was done on an independent set of 40 subjects. The actual and predicted values of MDWS of permanent canines and premolars were compared by paired samples t test in both groups, for both arches. The accuracy of equations derived from group A was higher than those derived from group B. The difference between actual and predicted values was statistically insignificant in group A and statistically significant in group B. The results confirm the accuracy of simple linear regression equations derived from a sample of children with no intermaxillary tooth-size discrepancy.

TOOTH SIZE DISCREPANCIES AND DENTAL ARCH WIDTH IN PATIENTS WITH PALATALLY AND LABIALLY IMPACTED MAXILLARY CANINES

It has been reported that labial displacement of the upper permanent canine is most frequently associatedwith crowding and constriction of the dental arch, but palatally impacted canines have sufficient space to erupt and are associated with a reduction of teeth width.Aim. To compare the Bolton ratios, individual tooth and dental arch widths in patients with unilateral palatallyand labially impacted canines.Methods. The study sample consisted of 75 patients with unilaterally impacted maxillary canines (palatalimpaction group n=48 (64%), labial impaction group n=27 (36%)). Teeth width, upper dental arch width and form analysis was performed on the pre-treatment dental casts. Bolton‘s ratio was calculated.Results. There were no differences in tooth widths between palatal and labial impaction groups, (except central incisors that were significantly smaller on the impaction side in both groups). No statistical relationbetween impacted tooth position on labio–palataldirection and meaning of the Bolton’s ratio was found. 54.66 % of patients had normal anterior Bolton‘s ratio and 53.33%- normal overall Bolton‘s ratio.The distance between upper first molars and first premolars does not differ in both impaction groups. No statistical correlation was found between the upperdental arch form and impacted canine position in labio-palatal direction.Conclusion. Central incisors were significantly smaller on the impaction side of the dental arch in both palatally and labially impaction groups. No differences in the Bolton ratios, dental arch form and transversal width in patients with unilateral palatallyand labially canine impaction were found.

Estimation of Tooth Size Discrepancies among Different Malocclusion Groups

ABSTRACTRegards 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.

Interarch Tooth Size Relationship of Indian Population: Does Bolton's Analysis Apply?

ABSTRACT Background Orthodontists have several methods to detect inter arch-tooth size discrepancies in patients presenting for orthodontic treatment. Many methods such as Pont's analysis, Nance and Carey's analysis, Peck and Peck ratio, Bolton's analysis are commonly used methods. A thorough search of literature reveals a paucity of reliable data on the mesiodistal dimensions of the crowns of the permanent dentition of Indian population. Without information about the size of individual tooth and groups of teeth for Indian population, it is difficult for the clinician to make an adequate diagnosis and treatment plan and to carry out a plan of therapy. Aim To determine the size of individual permanent tooth and the sex differences, with tooth size ratios according to Bolton's formula and to evaluate the reliability of Bolton's norms (Anterior/Posterior) in Indian population. Materials and methods One hundred and twenty cases in which an excellent occlusion was naturally existent with the mean age of 22 years (18-27 years) were selected in the study. The casts were prepared after taking alginate impression of maxillary and mandibular arches and pouring them immediately with dental stone. A sliding Digital Vernier calliper used to measure the teeth. The ratios of the mean of mesiodistal dimensions of types of teeth were computed. Results The mean overall ratio for the Indian population is found to be 92.11 with a standard deviation of 2.12. The values ranged from 86.50-97.13 and the median is 92.16. The mean anterior ratio for the Indian population is found to be 78.14 with a standard deviation of 2.59. Conclusion Bolton's original data does not represent Indian population. In our study Greater size variability was found in maxillary teeth as compared with mandibular teeth except mandibular first molar. Our study indicated that populationspecific standards are necessary for clinical assessments. Significant differences were shown for the overall ratio and anterior ratio for both sexes as compared to Bolton's ratio. How to cite this article Subbarao VV, Regalla RR, Santi V, Anita G, Kattimani VS. Interarch Tooth Size Relationship of Indian Populations: Does Bolton's Analysis Apply? J Contemp Dent Pract 2014;15(1):103-107.