Bolton Ratios Research Articles

Assessing the accuracy of two posterior tooth-size discrepancy prediction methods based on virtual occlusal setups.

To assess accuracy of the Bolton and Johnson/Bailey (JB) analyses in identifying clinically significant posterior tooth-size discrepancies using virtually constructed occlusal setups. Virtual models and cone-beam computed tomography data sets from 30 patients were utilized to construct 60 (two per patient) virtual posterior occlusal setups. Observed discrepancies in cusp-embrasure relationships were compared to estimated posterior interarch tooth-size discrepancies (ITSDs) calculated via Bolton and JB posterior analyses. Clinical significance for discrepancies was established at >1 mm from ideal cusp-embrasure relationships in accordance with current American Board of Orthodontics methodology. Data within groups were normally distributed, thus comparisons were completed via paired t-tests. Paired nominal data were analyzed utilizing McNemar's test, and simple linear regression was used to model the relationship of predicted to observed discrepancies. McNemar's test revealed significant differences (P ≤ .05) between the Bolton and JB groups' frequencies in matching the virtual setups correctly. JB predictions matched 100% (right) and 97% (left) setups; whereas, Bolton predictions matched only 23% (right and left) setups. A positive correlation was observed between JB predictions and cusp-embrasure discrepancies, demonstrating that average posterior discrepancy values increased 0.28 mm for every 1 mm predicted via the JB analysis. The JB analysis correctly characterized, but overestimated, the degree of posterior ITSDs corresponding to a clinically significant discrepancy in the virtual setups. Algebraically calculated posterior ITSDs based on the Overall and Anterior Bolton ratios were not accurate predictors of discrepancies observed in the virtual setups. Both Bolton and JB demonstrated weaknesses that limit precise identification of clinically significant ITSDs.

Comparison between Class II Division 1 and 2 Malocclusions and Normal Occlusion regarding Tooth Size Discrepancy and Arch Dimensions using Digital Models

The orthodontists grant a considerable importance to dental arch dimensions to attain more stability of the dentition and better esthetics. The aim of this study was to measure tooth size disharmony and dental arch dimensions in both divisions of class II malocclusion and compare them to Normal occlusion as a control group using three dimensional digital models obtained from 3Shape E1 laser scanner (3Shape, Copenhagen, Denmark). This work was performed on 120 dental casts randomly selected from the records of patients (age range 16- 22 years) attending the Department of Orthodontics, Faculty of Dentistry, Mansoura University. Various parameters were measured including anterior and overall Bolton ratios, maxillary and mandibular intercanine, interfirst premolar and intermolar widths, maxillary and mandibular arch depth, palatal depth, depth of curve of Spee, overjet and overbite. Mean and standard deviation were calculated. One-way ANOVA was used to detect possible differences between groups. The findings indicate that Class II division 1 malocclusion showed significantly greater maxillary arch depth, palatal depth, mandibular intercanine, interpremolar and intermolar widths and larger overjet amount in comparison with Class II division 2, while revealed significantly higher values of maxillary arch depth, mandibular intermolar width, curve of Spee, overjet and overbite than Normal Class I. On the other hand Class II division 2 malocclusion had significantly greater overall Bolton ratio, maxillary intermolar width, curve of spee depth and overbite than Class II division 1, while it showed deeper curve of Spee and larger amount of overjet and overbite compared to Normal Class I. The results of the current study can help the clinicians in treatment planning and provide guidance for proper selection of arch wires to obtain post-treatment stability.

Comparison of Bolton ratio in normal occlusion and different malocclusion groups in Iranian population

Bolton ratio is used as a method for diagnosis of tooth size discrepancy. Tooth size discrepancy has an important role in the stability of results of final orthodontic treatment. The aim of this study was to determine and compare Bolton ratio in normal occlusion and different malocclusion groups of Iranian population. This descriptive-analytic study comprises 240 orthodontic patient casts (for every malocclusion group: class I, class II division 1, class II division 2, class III, 30 males and 30 females) which have fully erupted and complete permanent dentitions from first molar to first molar, and also 60 persons (30 male-30 female) with normal occlusion. The mesiodistal tooth sizes were measured using digital caliper two times with a 4-week interval. The average mesiodistal size of all teeth in the malocclusion group was significantly bigger than in the normal occlusion group. Although there was no relationship between anterior ratio and gender or malocclusion groups, but a significant relationship between total ratio in Class II division 1 and normal occlusion was seen. Furthermore, a significant difference between anterior and total ratios in the present study and original Bolton's values was found. In the normal occlusion group, the anterior and total ratios were bigger than those in Bolton's original study. Also, "class II division 1" showed the lowest values of Bolton ratio among the other normal occlusion and malocclusion groups. Therefore, the original Bolton's values should be used conservatively in Iranian population.

Orthodontic perspective in causing the severity of malocclusion in hypodontia patients: A clinical study

Aim: This study was aimed to compare Bolton's ratio and the arch width of patients with hypodontia with that of the control group. Materials and Methods: Ten cases with congenitally missing teeth and 10 cases of the control group were grouped in this study. It was guided by Bolton's ratio and Ashley Howe's analysis considering the tooth material and comparing tooth material to jaw size in the latter. Tooth width measurements were compared using a t-test, statistically significant at P 0.05). Arch width analysis showed significantly reduced basal arch width dimensions in hypodontia patients (P

Three-dimensional comparison of 2 digital models obtained from cone-beam computed tomographic scans of polyvinyl siloxane impressions and plaster models.

PurposeThis study was performed to evaluate the dimensional accuracy of digital dental models constructed from cone-beam computed tomographic (CBCT) scans of polyvinyl siloxane (PVS) impressions and cast scan models.Materials and MethodsA pair of PVS impressions was obtained from 20 subjects and scanned using CBCT (resolution, 0.1 mm). A cast scan model was constructed by scanning the gypsum model using a model scanner. After reconstruction of the digital models, the mesio-distal width of each tooth, inter-canine width, and inter-molar width were measured, and the Bolton ratios were calculated and compared. The 2 models were superimposed and the difference between the models was measured using 3-dimensional analysis.ResultsThe range of mean error between the cast scan model and the CBCT scan model was −0.15 mm to 0.13 mm in the mesio-distal width of the teeth and 0.03 mm to 0.42 mm in the width analysis. The differences in the Bolton ratios between the cast scan models and CBCT scan models were 0.87 (anterior ratio) and 0.72 (overall ratio), with no significant difference (P>0.05). The mean maxillary and mandibular difference when the cast scan model and the CBCT scan model were superimposed was 53 µm.ConclusionThere was no statistically significant difference in most of the measurements. The maximum tooth size difference was 0.15 mm, and the average difference in model overlap was 53 µm. Digital models produced by scanning impressions at a high resolution using CBCT can be used in clinical practice.

Do Dental Arches Lengths, Widths and Perimeters affect Bolton's Ratios?

Do Dental Arches Lengths, Widths and Perimeters affect Bolton's Ratios?

Do Dental Arches Lengths, Widths and Perimeters Affect Bolton's Ratios?

Do Dental Arches Lengths, Widths and Perimeters Affect Bolton's Ratios?

Bolton's Ratios in Normal, Spaced and Crowded Dental Arches (Iraqi Study)

Bolton's Ratios in Normal, Spaced and Crowded Dental Arches (Iraqi Study)

Principles and considerations of orthodontics for Prosthodontic treatment

Outcome of esthetic ceramic restorations are affected by tooth size, gingival contour, occlusal relationship, etc. For this reason, demand of orthodontic treatment before esthetic ceramic restoration is increasing. If a Bolton ratio discrepancy, a problem of the maxillary incisor's vertical position, a problem of inclination of anterior teeth, a pathogenic occlusion is existed, a pre-prosthodontic orthodontics should be accomplished. These problems can be satisfactory only after the prosthetic treatment is performed after orthodontic treatment. When orthodontic treatment is given, it should be treated with the following principle. 1. Treat it in the direction of functioning occlusion. 2. Keep the patient's stable occlusal scheme. 3. Treat the teeth by considering the average tooth size and Bolton ratio. Ortho-Prostho combined treatment with optimal treatment plan can lead a patient's function, esthetics, and long-term stability.

A Comparative Analysis of Tooth Size Discrepancy between Male and Female Subjects Presenting with a Class I Malocclusion.

Objectives To evaluate the tooth size discrepancy and Bolton's ratios between male and female subjects with a Class I malocclusion. Materials and Methods The digital e-models of 100 male and 100 female 12-year-old southern Chinese children with a Class I malocclusion were selected. The mesiodistal widths from permanent first molar to the contralateral side first molar of the upper and lower dentitions were measured. Differences between the tooth size discrepancy, together with the anterior and overall Bolton's ratios between male and female subjects, were assessed using a two-sample t-test. A paired t-test was used to determine differences between antimetric pairs of teeth within the same arch. Results Females had statistically significant smaller teeth than males (P < 0.05) except the upper left and lower left lateral incisor and lower left and right central incisors. The mean values of anterior Bolton's ratios for males and females were 77.04 and 77.03, respectively (P > 0.05), while the mean values of overall Bolton's ratios of male and female are 90.48 and 90.65, respectively (P < 0.05). The clinical significant differences (Cohen's d > 0.2) for contralateral tooth size were shown on the maxillary canines, lateral incisors, and central incisors of males; and mandibular canines and lateral incisors of females. Conclusions Southern Chinese females presenting with Class I malocclusions have smaller mesiodistal tooth dimensions compared to males. Both males and females presented several tooth size asymmetries. There are no statistical differences in anterior and overall Bolton's ratios between the genders.

Bolton Ratios in Crowded and Non-Crowded Dentition among Solapur Population: An In-vitro Study

Bolton Ratios in Crowded and Non-Crowded Dentition among Solapur Population: An In-vitro Study

Dental arch dimensions, form and tooth size ratio among a Saudi sample.

Objectives:To determine the dental arch dimensions and arch forms in a sample of Saudi orthodontic patients, to investigate the prevalence of Bolton anterior and overall tooth size discrepancies, and to compare the effect of gender on the measured parameters.Methods:This study is a biometric analysis of dental casts of 149 young adults recruited from different orthodontic centers in Jeddah, Saudi Arabia. The dental arch dimensions were measured. The measured parameters were arch length, arch width, Bolton’s ratio, and arch form. The data were analyzed using IBM SPSS software version 22.0 (IBM Corporation, New York, USA); this cross-sectional study was conducted between April 2015 and May 2016.Results:Dental arch measurements, including inter-canine and inter-molar distance, were found to be significantly greater in males than females (p<0.05). The most prevalent dental arch forms were narrow tapered (50.3%) and narrow ovoid (34.2%), respectively. The prevalence of tooth size discrepancy in all cases was 43.6% for anterior ratio and 24.8% for overall ratio. The mean Bolton’s anterior ratio in all malocclusion classes was 79.81%, whereas the mean Bolton’s overall ratio was 92.21%. There was no significant difference between males and females regarding Bolton’s ratio.Conclusion:The most prevalent arch form was narrow tapered, followed by narrow ovoid. Males generally had larger dental arch measurements than females, and the prevalence of tooth size discrepancy was more in Bolton’s anterior teeth ratio than in overall ratio.

Bolton ratios in Portuguese subjects among different malocclusion groups.

BackgroundSeveral methods have been described to estimate inter-arch tooth size relationship, such as Bolton’s ratios. The aims of this study were to verify the validity of Bolton indexes in a sample of untreated Portuguese subjects based on Angle classification and to evaluate the gender difference.Material and Methods168 pre-treatment dental casts of orthodontics Portuguese subjects (59 males and 109 females) with different occlusions were used, which were selected randomly from 541 consecutively treated orthodontic patients. The mesiodistal widths from first molar to first molar were measured on each pre-treatment cast to the nearest 0.01 mm using digital caliper, and Bolton’s anterior and overall ratios were calculated. Descriptive statistics as mean, standard deviation and range were calculated. Moreover, the results were compared to Bolton’s ratios and differences based on gender and occlusion groups were evaluated by statistical inference methods.ResultsThe results reveal that the mean values, standard deviation and range were larger than Bolton’s in normal occlusion group (78.3±3.5% in anterior ratio and 92.1±2.2% in overall ratio) and there were no differences between genders (p >0.05). Class I (anterior and overall ratios, p=0.001 and p<0.001, respectively), Class II/2 (anterior ratio, p=0.032) and Class III (overall ratio, p=0.041) were significantly different from Bolton’s reference data.ConclusionsThe results showed no differences between gender and no difference between normal occlusion and malocclusion groups. Moreover, in normal occlusion group, the anterior and overall tooth size ratios was equivalent to the original Bolton’s ratios, although the mean and standard deviation were large. Key words:Bolton anterior and overall ratios, normal occlusion, malocclusion, portuguese population.

Evaluation and comparison of tooth size discrepancies among different malocclusion groups

Introduction: The compliance of proportions between the mesiodistal dimensions of the upper and the lower teeth is necessary for good intercuspidation. Given that a significant discrepancy in tooth size can prevent ideal occlusion at the end of orthodontic treatment, the absence of tooth size discrepancy is a significant factor for the realization of the ideal occlusion.The aim: Aim of this study was to determine whether there is a difference in the incidence of tooth size discrepancies among different skeletal malocclusion groups in the orthodontic patients.Material and methods: The sample comprised 300 pretreatment study casts (118 males and 182 females) with fully erupted andcomplete permanent dentition except third molars, which were selected randomly from records of orthodontic patients. All subjects were divided in three groups, according to the Angle classification of malocclusion. The measurements were made on study models with digital calipers accurately to 0.01 mm.The Class was defined by using the Steiner analysis on lateral cephalograms.The subjects were divided into three groups depending on the value of the ANB angle. For every subject, the value of the angles SNA, SNB and ANB was measured.The reliability of measurements was examined by the Pearson’s correlation coefficient. To determine whether there were gender differences an independent sample t-test was performed.Results: There is no statistically significant differences in Bolton’s discrepancy by different gender, or at different classes. The averagevalue of the anterior Bolton ratio was 78.16 and of the overall were 90.87. Values of the anterior and overall Bolton ratios are highestin patients with Class III. The highest average value of anterior discrepancy was in male subjects with III Class (-0.72), while the highest average value of overall discrepancy was in male subjects with II Class (0.65).Conclusion: The results of the study show that there are no statistically significant differences in Bolton’s discrepancy by different gender, or at different classes.

THE RELIABILITY OF THE BOLTON RATIO WHEN APPLIED TO THE INDONESIAN POPULATION

Objective: The objective of this study is to determine whether Bolton ratio can be applied clinically to the Indonesian population and to determine a more suitable Bolton ratio for the Indonesian population.Methods: This study was conducted on 120 readily available study models of treated cases comprising 37 males and 83 females. Two investigators separately measured the mesiodistal crown width of maxillary and mandibular tooth on each study model using sliding calipers. According to Bolton’s method, the overall and anterior ratios from each sample were calculated and the mean was generated. Using Student’s t-test with a 95% confidence interval, the investigators compared whether there is a significant difference between the ratio from Bolton’s samples and the ratio from the Indonesian samples.Results: The result of this study showed that, for Indonesian samples, the overall ratio is 89.7±2.05, while the anterior ratio is 76.4±2.76. Student’s t-test showed that there is a statistically significant difference (p&lt;0.05) between the results of this study and that of Bolton’s study for both the anterior and overall ratios.Conclusion: It can be concluded that there is a difference between Indonesian population and Caucasian population in tooth size and Bolton ratio value. Therefore, original Bolton ratio value cannot be used as an accurate diagnostic tool for Indonesian population.

The Comparison of Diagnostic Measurements Using Two Different Three-Dimensional Digital Orthodontic Model Software Systems

Objective: The purpose of this study was to evaluate and compare the reliability and accuracy of diagnostic measurements performed using two different three-dimensional (3D) digital orthodontic model software systems. Materials and Methods: The dental casts of 20 patients with permanent dentition were selected and scanned with an orthodontic 3D scanner (3Shape R700, Copenhagen, Denmark). Two different digital model software programs, Orthomodel (v.1.01, Orthomodel Inc., Istanbul, Turkey) and O3DM (v.2.0, O3DM Thunoegade, Aarhus C, Denmark) were used for diagnostic measurements including tooth width, Bolton discrepancies, intermolar and intercanine distances. A total of 34 measurements were calculated on each digital model. All measurements were repeated by the same observer over 10 randomly selected dental casts at least two weeks later for intraobserver reliability. Results were analyzed statistically. The paired samples t-test was used to compare the differences between the measurements obtained with both softwares. The intraobserver reliability was determined using Cronbach’s alpha test. Results: Cronbach’s alpha value indicated a very high level of reliability for all measurements. Orthomodel and O3DM software programs showed significant differences in the mesiodistal widths of some teeth and the sum of maxillary 6 teeth widths (p&lt;0.05), but not in the Bolton ratios and transverse arch width measurements. Conclusions: Both digital model softwares demonstrated clinically acceptable measurements despite of the differences in some measurements essential for diagnosis and treatment planning.

The applicability of Bolton's tooth size ratios for population-specific malocclusion

Aims: This study aims to evaluate the Bolton ratio in Beed population in Maharashtra with different malocclusion. Materials and Methods: Fifty study casts were taken from the patients undergoing orthodontic treatment, and individuals were divided into three groups: Group I (Angle's Class I, n = 25), Group II (Angle's Class II, n = 25), and Group III (mean of Group I and Group II). Statistical Analysis Used: ANOVA and Tukey's test. Results: A mean total Bolton ratio of 93.05 ± 5.87 and a mean anterior Bolton ratio of 81.08 ± 5.93 were found for the sample; significantly, higher mean anterior tooth ratios were found for Group I (Angle's Class I) patients (P Conclusions: Mean anterior tooth size discrepancy for Angle Class I individuals was significantly greater compared to Bolton's mean anterior ratio.

Tooth width measurement using the Lythos digital scanner

Abstract Introduction Digital models have become more widely accepted for orthodontic diagnostic purposes. Intraoral scanners have the advantage of eliminating the need for conventional impressions. The aim of the present study was to assess the reliability and reproducibility of the Lythos intraoral scanner and to determine if a significant advantage is delivered over stone model and caliper measurements in tooth width and Bolton ratio accuracy. Methods The study comprised 30 typodont models for which conventional alginate impressions and digital scans were obtained to generate stone and digital models, respectively. Mesiodistal tooth width measurements and Bolton ratios were obtained with either calipers and stone models or with Digicast (Ormco Lythos digital model software, Ormco, CA, USA) software using digital models. Pearson’s correlation coefficients tested intra-examiner reliability. Interclass correlation coefficients were used to assess agreement between examiners (reproducibility). The differences in the mean tooth width measurements and Bolton ratios from the typodont values and either the digital or conventional method were used to assess validity by applying two tailed t-tests. Results The measurements obtained from the Lythos and stone models had near perfect intra-examiner agreement (Pearson ≥ 0.98). The inter-examiner reproducibility for tooth widths, anterior Bolton and overall Bolton ratio was high and similar for both methods (Lythos scanner Interclass correlation coefficient (ICC) above 0.89, stone models ICC above 0.92). Stone model measurements were statistically twice as accurate as those derived from the digital system (0.032 mm versus 0.074 mm). There were no significant differences in accuracy between the methods for Bolton calculations. Clinically, there was no difference between the methods for tooth width measurements and Bolton calculations. Conclusions The Lythos system is as reliable and reproducible as conventional calipers and stone models in tooth width measurements and Bolton calculations. The caliper method presents a statistically more valid tooth width measurement technique but the clinical significance of this is questionable.

Bolton analysis of the maratha population in Pune

Objective: To evaluate the Bolton ratio in the Maratha population in Pune with near ideal occlusion. Materials and Methods: Fifty study casts were made from impression obtained from patients (25 males and 25 females) aged between 15 and 30 years visiting the Department of Orthodontics and Dentofacial Orthopedics at Sinhgad Dental College and Hospital, Pune. 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. t-test was used for the statistical analysis. Results: The mean overall and anterior ratios were found to be 92.73 and 80.48 with standard deviation of 2.69 and 2.86, respectively. The range of overall ratio was 81.91–96.75, and the range of anterior ratio was 74.75–86.45. The values obtained from this study indicated that there was a statistically significant difference between the overall and anterior ratios of Maratha and Caucasian participants. Conclusion: It can be suggested that new values should be obtained for the Maratha population as the values were found to be significantly different from the Bolton values obtained for Caucasian population. Hence, population-specific standards are necessary to be formed for clinical assessment.

Bolton tooth size ratio among qatari population sample: An odontometric study.

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.