Anterior Bolton Ratios Research Articles

A Comparative Study of Two Smartphone Applications and a Traditional Orthodontic Model Analysis Method

Introduction An orthodontic study used to determine whether teeth are positioned appropriately and whether there is an opportunity for orthodontic therapy or tooth extractions by model analysis. While certain manual model studies can be laborious and time-consuming, there are smartphone applications that can simplify the mathematical calculations necessary for orthodontic cast model analysis.  Objective The purpose of this research is to compare the outcomes and processing times of model analysis utilizing two smartphone apps, such as Model Analysis App and iModel Analysis, and the traditional technique.  Materials And Methods This is a comparative analytic study. The samples are made up of thirty dental casts that underwent several model studies, including as the Boltons, Ashley-Howe, Carey’s and Arch Perimeter assessments. A comparison in results and time was carried out for these model analyses using three methods - conventional method, iModel Analysis App and Model Analysis App.  Results The conventional technique gave results for a Bolton's overall ratio analysis of 3.3967±3.44579, iModel Analysis produced results of 3.4333±3.77709, while the Model Analysis app produced results of 4.6200±6.83744. The conventional technique yielded results for Bolton's anterior ratio analysis of 4.9133±5.81969; iModel Analysis produced results of 4.7700±5.57743; and the Model Analysis app produced results of 4.7500±5.59068. The results of arch perimeter discrepancy analysis for conventional method were 4.0000±3.15135, those for iModel Analysis was 4.0000±3.15135, and for Model Analysis app it was 4.0000±3.15135. The results of Carey’s discrepancy analysis for conventional method were 3.8667±2.59620, those for iModel Analysis was 3.8667±2.59620, and for Model Analysis app it was 3.8667±2.59620. The results of Ashley - Howe PMBAW% analysis for conventional method were 44.0200±3.71255, those for iModelAnalysis was 42.1367±5.74531, and for Model Analysis app it was 43.8133±3.71787. The results of Pont’s expansion analysis for conventional method, iModel Analysis and for Model Analysis app showed p value 0.114 (not significant = p>0.05). The results of period required for the analysis by conventional method were 903.3000±30.19951, while those for iModelAnalysis was 399.2000±42.94375, and for Model Analysis app it was 392.0333±35.58233.  Conclusion There was no critical distinction within the results of the examinations done by the different methods. However, there was a noteworthy contrast within the time duration required to carry out the examination by conventional methods and that of iModelAnalysis and Model Analysis App.

Tooth size discrepancy: Digital vs manual measurement

Background/Aim: The aim of this study was to determine the accuracy of overall and anterior Bolton's ratio measurements obtained with an intraoral scanner compared to standard caliper measurements on plaster models. Material and Methods: This study included 33 subjects (18 female and 15 male), aged 12 to 18 years. All subjects were taken impression for the purpose of making study plaster models. In addition, all subjects underwent intraoral scanning for the purpose of creating digital models. Tooth width was measured with a caliper on plaster models, while digital models were analyzed using Cerec Ortho SW 2.0.2 software. The overall and anterior Bolton ratios were derived using both methods. Statistical data processing was performed using an independent t-test. Results: The results obtained using these two methods for measuring the anterior and overall Bolton ratio showed that there was no statistically significant difference in the measurements obtained on plaster models and the measurements obtained by intraoral scanning. For the overall Bolton ratio, T-test was 0.828 and is not statistically significant (p<0.05). The value of T-test for the anterior Bolton ratio was 0.001 and it was also not statistically significant (p<0.05). Conclusions: Determination the overall and anterior Bolton ratio using an intraoral scanner is an accurate and acceptable method for clinical work in orthodontics.

Evaluation of the anterior and overall tooth ratios in the Saudi population versus Bolton's standards.

Understanding tooth-size discrepancy is essential in the process of diagnosis of maxillary and mandibular relationship. Due to the high incidence of tooth-size disproportion, Practitioners should consider the high incidence of tooth-size disproportion when planning treatment for their patients, as in many cases, this can be a hindrance to obtaining an ideal result. This study aimed to determine the anterior and overall tooth ratios in the Saudi population and compare them with Bolton's standards. A total of 356 patients were recruited. For the anterior ratio, around 25% of the patients had a ratio equal to Bolton's standards (77.2%). Most subjects (53.7%) had a ratio above 77.2%, and the remaining (20%) had a ratio below 77.2%. The mean amount of anterior mandibular excess was 2.17 ± 2.12 mm, and the mean amount of anterior maxillary excess was 2.16 ± 2.08 mm. For the overall ratio, less than half of the participants (43%) had a ratio equal to Bolton's standards (91.3%). Almost 34% had a ratio above 91.3%, while 23% of the participants had a ratio below 91.3%. The mean amount of overall mandibular excess was 2.54 ± 2.37 mm, and the mean amount of overall maxillary excess was 3.31 ± 3.33 mm. The majority of the study sample had an overall and anterior Bolton ratio that is different from the norms of Bolton's standards, with a tendency for increased overall and anterior ratios. Having specific standards for the Saudi population is important for better clinical assessment and treatment outcomes.

Artificial neural network model for predicting sex using dental and orthodontic measurements

To investigate sex-specific correlations between the dimensions of permanent canines and the anterior Bolton ratio and to construct a statistical model capable of identifying the sex of an unknown subject. Odontometric data were collected from 121 plaster study models derived from Caucasian orthodontic patients aged 12-17 years at the pretreatment stage by measuring the dimensions of the permanent canines and Bolton's anterior ratio. Sixteen variables were collected for each subject: 12 dimensions of the permanent canines, sex, age, anterior Bolton ratio, and Angle's classification. Data were analyzed using inferential statistics, principal component analysis, and artificial neural network modeling. Sex-specific differences were identified in all odontometric variables, and an artificial neural network model was prepared that used odontometric variables for predicting the sex of the participants with an accuracy of > 80%. This model can be applied for forensic purposes, and its accuracy can be further improved by adding data collected from new subjects or adding new variables for existing subjects. The improvement in the accuracy of the model was demonstrated by an increase in the percentage of accurate predictions from 72.0-78.1% to 77.8-85.7% after the anterior Bolton ratio and age were added. The described artificial neural network model combines forensic dentistry and orthodontics to improve subject recognition by expanding the initial space of odontometric variables and adding orthodontic parameters.

Biometric parameters of the upper dental arch in patients with a stable result of orthodontic treatment of abnormal position of the crowns of the maxillary canines

Aim to evaluate the metric parameters of the upper dentition in patients with a stable result of orthodontic treatment of anomalies in the position of the crowns of the upper canines in the long-term follow-up period.
 Material and methods. We conducted an open study on a sample of patients after orthodontic treatment using clinical and instrumental methods. We analyzed 126 clinical cases of patients aged from 18 to 44 years with completed orthodontic treatment of abnormal position of the crowns of the maxillary canines with satisfactory aesthetic and functional results. The duration of the retention period ranged from 5 to 10 years. 75 patients met the inclusion criteria for the study.
 Results. The study showed that the biometric parameters of the dental arches after the end of orthodontic treatment did not always correspond to the individual norm of a patient. An increase in the transversal size of the upper dentition in the region of the premolars was determined in 44 patients (58.6%), a slight narrowing in the region of the first molars in 34 patients (45.4%), lengthening or shortening of the anterior part of the dental arch in 32 (42.7%) and 23 (30.6%) patients, respectively. With the proportionality of the mesio-distal dimensions of the incisors of the upper and lower jaws (Tonn's Index 1.340.03) and the relative macrodontia of the canines of the lower jaw (anterior Bolton's ratio 81.03.2%), the symmetrical position of the crowns of canines of the upper jaw and the value of the rotational angle of 28.02.1corresponded to the functionally optimal results of orthodontic treatment.
 Conclusion. Aesthetically satisfactory and functionally stable results of orthodontic treatment of patients with anomalies in the position of the crowns of the maxillary canines during the retention period correspond to the following biometric parameters of the upper dental arch and / or their combination: lengthening of the anterior region, an increase in the transversal size in the region of the first premolars and a decrease in the region of the first molars in maintaining the individual norm of intercanine width. The stability of the results of orthodontic treatment in patients with anomalies in the position of the canines and the shape and / or size of the dental arches is ensured by the maximum possible leveling of violations of the anatomical and topographic norms of the teeth position.

A simple method for quick evaluation of the anterior tooth ratio: an observational study

BackgroundAn ideal relationship of anterior teeth is closely related to postoperative function, stability, and aesthetics. Therefore, it is necessary to estimate the proportion of anterior teeth when communicating with patients about possible treatment plans and outcomes. This study aimed to establish a simple method for assessing the proportion of anterior teeth and to identify the standard ratio value to provide references for clinical work.MethodsFive hundred fourteen patients were divided into derivation, standard, and validation datasets. We first deduced our novel simplified anterior tooth ratio (SATR) by finding the key teeth with the derivation datasets, then established standard values by measuring the standard models, and finally validated the diagnostic performance of SATR. Independent sample t-test was used to select key teeth. Pearson’s correlation analysis and linear regression analysis was used to test and verify the correlation between SATR and the anterior Bolton ratio. Chi-square test and diagnostic test were used to verify the diagnostic results using SATR. P values of < 0.05 were considered statistically significant.ResultsPatients with an abnormal anterior Bolton ratio were more likely to have variations in the maxillary and mandibular lateral incisors. Therefore, the ratio of maxillary and mandibular lateral incisors was chosen as a simple way to assess the anterior tooth ratio and was defined as SATR (simplified anterior tooth ratio). A positive correlation was observed between SATR and anterior Bolton ratio (r = 0.702, p < 0.001), with the linear regression equation as follows: y = 0.503 + 0.328x, x = SATR, y = anterior Bolton ratio. The standard value of SATR was established (85.69% ± 3.57%) and proven reliable in clinical practice.ConclusionsThe ratio of maxillary and mandibular lateral incisors can be used to estimate the anterior tooth ratio, which showed high reliability and efficiency.

Anterior Tooth Size Discrepancy in Class III Surgical Patients.

The purpose of the present study was to specify whether there are mesiodistal tooth size discrepancies in the anterior region in patients with dentoskeletal Class III malocclusion who underwent orthognathic surgery and orthodontic treatment and to assess the relationship between anterior Bolton ratio and dentoskeletal cephalometric measurements. The diagnostic dental casts and lateral cephalometric radiographs of 113 nongrowing patients (54 females and 59 males; mean age: 19.96 ± 4.42 years) with dentoskeletal Class III malocclusion who underwent orthognathic surgery and orthodontic treatment were included in the study. The mesiodistal widths of the 6 anterior teeth were measured from dental casts using a digital caliper accurate to 0.01 mm and anterior Bolton ratios were calculated. Lateral cephalograms were digitalized and used to measure 4 skeletal and 4 dental parameters. The mean anterior ratio of Class III surgical patients was 80.1% with a standard deviation of 2.8%. Clinically significant anterior tooth size discrepancies (greater than ±2 standard deviation) were found in 40.7% of the sample, 97.8% of those patients having anterior mandibular tooth excess. No significant correlation was found between the anterior Bolton ratio and cephalometric measurements. Clinicians should consider the probability of tooth size discrepancy in the diagnosis and treatment planning of Class III surgical patients and should perform interventions to eliminate these discrepancies during presurgical orthodontic treatment.

Digital versus conventional full-arch impressions in linear and 3D accuracy: a systematic review and meta-analysis of in vivo studies.

The purpose of this systematic review was to compare the accuracy of digital and conventional full-arch impressions in vivo. This systematic review was conducted according to the PRISMA and registered at the PROSPERO (CRD42021232736). Electronic and hand searches were performed to identify in vivo studies comparing the linear or 3D accuracy of digital and conventional impressions. The risk of bias (ROB) of included studies was assessed by QUADAS-2, and the overall quality of evidence was assessed by GRADE. Twenty-two studies met the inclusion criteria, and 13 studies were included in the meta-analysis. There was no significant difference between digital and conventional impressions in the linear measurements of tooth width, anterior Bolton ratio, overall Bolton ratio, intercanine distance (ICD), and intermolar distance (IMD). The repeated measurement mean errors (RMEs) were less than 0.1 mm, the intra-examiner intraclass correlation coefficient (ICC) values were more than 0.9, and the inter-examiner ICC values were more than 0.87 for both impression techniques. The 3D deviation between digital and alginate impressions was 0.09 mm. The 3D precision of both impression techniques was less than 0.1 mm. The trueness of digital and alginate full-arch impressions was similar, and both impression techniques showed high precision. More research was needed to compare digital impressions and other conventional impression materials. For patients with completely natural dentition, the digital impressions obtained directly from intraoral scanning can be considered a viable alternative to alginate impressions.

Are facial, maxillary arch and incisor dimensions related in patients with a unilaterally impacted palatal canine? A prospective investigation

Abstract Objective To identify and determine the relationship between facial, maxillary arch and incisor dimensions of patients presenting with a unilaterally impacted palatal canine. Methods Prospective referrals over one calendar year of patients identified with a unilaterally impacted palatal canine were compared with prospectively recruited control subjects. Canine location was determined radiographically and re-confirmed two weeks later. Facial, maxillary arch and incisor dimensions were assessed. Intra-examiner reproducibility was re-assessed using randomly selected images (20%, n = 40). General linear models were applied for inter-group comparisons incorporating Bonferroni adjustment with categorical parameters assessed using Fisher’s exact test (SAS®, Version 9.4, SAS.com). Inter-class correlation coefficients were calculated for relationships between the variables. Results Fifty-four patients (37 females; 17 males) presenting with a unilaterally impacted palatal canine [mean age 14.5 (SD 1.7) years] and 54 control subjects (37 females, 17 males) [mean age 14.3 (SD 2.2) years] were recruited. Measurement error was small for landmark data (0.58 mm), palatal depth (0.09 mm), palatal area (0.42 mm²) and Bolton ratio (0.14%). For facial, maxillary arch and tooth shape assessments, landmark error was 0.05 mm with complete agreement for classification. The mean nasal basal width was smaller in the unilaterally impacted palatal canine group compared with the control group (P &lt; 0.0001) but face shape distribution and face ratio were similar (both P &gt; 0.05). The mean anterior Bolton ratio was larger in the impacted canine group (P &lt; 0.01). No differences were recorded between groups for other parameters (all P &gt; 0.05). No positive correlations were identified between the variables. Conclusions Patients with a unilaterally impacted palatal canine had a narrower mean nasal basal width and a larger mean anterior Bolton ratio compared to a control group but the clinical significance of the differences was considered minor. Facial, maxillary arch and incisor dimensions were neither individually nor collectively correlated with a palatal canine which may lend support to a genetic aetiology.

Validity of Arch Relationship Measurements in Digital Dental Models

The aim of the present study is to evaluate the validity of orthodontic measurements including tooth width, Bolton ratio, overjet and overbite on the digital dental models. Dental models of the subjects aged 12 to 18 were obtained in 3 different forms, which were conventional stone model, digital model created with Freedom HD model scanner, and digital model produced with CS3600 intraoral scanner. After measurements were made on the models, reliability and reproducibility of the measurements were evaluated by using intraclass correlation coefficient, while validity was assessed with paired t-test. As a result, significant reliability and reproducibility were verified, with intraclass correlation coefficient exceeding 0.750 in all groups. Measurements of the model scanned group showed an adequate validity in overall and anterior Bolton ratio, overjet, and overbite. Intraoral scanned models showed an adequate validity in anterior Bolton ratio, and overjet. Measurement on intraoral scanned digital models can be considered as an alternative for young children who have difficulty in taking impression. Furthermore, careful considerations on measurement error should be made in clinical situations.

Buccolingual and Mesiodistal Dimensions of the Permanent Teeth, Their Diagnostic Value for Sex Identification, and Bolton Indices.

Introduction We aimed (1) to measure the mesiodistal and buccolingual widths of the permanent dentition in Iranian orthodontic patients, (2) to determine cut-off points for sex identification based on the mesiodistal and buccolingual diameters, and (3) to calculate Bolton indices. Methods The mesiodistal and buccolingual dimensions of 28 maxillary and mandibular permanent teeth in 331 Iranian nonsyndromic orthodontic patients (dental casts and radiographs) aged 12 to 35 years old with fully erupted permanent dentitions (except the third molars and some sporadic cases of a few teeth missing or excluded) were measured. The anterior, posterior, and overall Bolton ratios were calculated in cases with no missing teeth in the 6-to-6 range. Potentially associated factors (the skeletal Angle classes, crowding, sex, jaws, sides, and age), as well as the value of these measurements for sex determination and cut-off points for sex identification based on these measurements were assessed using receiver-operator characteristic (ROC) curves, analysis of variance (ANOVA), Tukey, unpaired t-test, partial and Pearson correlation coefficients, and multiple linear regression (α = 0.05). Results Sex dimorphism was very frequent (P ≤ 0.05 in 41 out of 56 measurements). Only the buccolingual widths of the maxillary lateral and the mandibular central and lateral differed across the Angle classes (ANOVA/Tukey, P < 0.05). Cut-off points were estimated for 38 dental measurements, which were proper for sex identification (P < 0.05), with 8 (2 maxillary and 6 mandibular) measurements being highly appropriate (having areas under ROC curves ≥ 64%, P < 0.05). Both the mandibular canines were the only teeth with all four measurements highly appropriate for this purpose. Controlling for the role of sex, aging was associated negatively with several crown dimensions (the buccolingual widths of the maxillary first and second premolar and mandibular second premolar and first molar; the mesiodistal diameters of the maxillary central, canine, first premolar, and first molar, mandibular central, lateral, first premolar, and first molar, P ≤ 0.05, partial correlation coefficient). There were significant correlations among crown sizes. All the 28 (right/left-averaged) measurements were smaller in microdontia cases (P ≤ 0.002). The anterior, posterior, and overall Bolton indices were 78.05, 105.42, and 91.87, respectively. There were correlations between the overall Bolton ratio with the other two Bolton ratios (Pearson R = 0.696, R = 0.740, P < 0.0005) but not between the anterior and posterior Bolton ratios (R = 0.045, P = 0.459). The skeletal Angle classes might not be associated with the overall and anterior Bolton ratios (ANOVA, regression, Pearson, P > 0.05). However, the posterior Bolton ratio was smaller in class II cases compared to classes I or III (Tukey, P ≤ 0.045). In the whole sample, there was no sex dimorphism in Bolton ratios (t-test, P > 0.05). However, in Angle class II patients, the anterior Bolton ratio was greater in men than in women (P = 0.014). Conclusions Sex dimorphism might be very common in the dentition of Iranians, with aging significantly reducing some measurements. The buccolingual widths of some incisors might differ across the skeletal Angle classes. Mandibular canines are the most appropriate teeth for sex identification. The Angle classes might not be associated with the anterior and overall Bolton ratios; nevertheless, the posterior Bolton ratio might be smaller in class II cases compared to others. In general, sex might not affect Bolton ratios; however, in class II patients, the anterior Bolton ratios might be larger in men.

Description of Bolton analysis on Balinese patients with crowded teeth in Mahasaraswati Denpasar University Dental Hospital

Bolton analysis is one of the analyzes used in determining tooth size discrepancies, the ratio of size of mesiodistal teeth is very important in determining orthodontic treatment plans so that good occlusion can be achieved as a result of treatment. The aim of this study is to find out the width of mesiodistal teeth crowded with Bolton's analysis of Balinese men and women. This des-criptive research method using purposive sampling technique, used 40 models study samples of male and female from Balinese patients at the Mahasaraswati Denpasar University Dental Hospital. The largest contour of mesial to distal dimension of the tooth measured parallel to the occlusal plane. The results obtained were anterior ratios and the overall analysis of Bolton in the Balinese tribe. The anterior ratio of the Balinese men and women was obtained at 79.55%±3.40 and 61.57%±5.32. The overall ratio of Balinese men and women was obtained at 91.66%±2.57 and 102.50%±5.26. It was concluded that Bolton's anterior ra-tio and Bolton's overall ratio in crowded teeth of Balinese men and women show an average value that exceeds Bolton's ideal value, so that the location of faulty teeth of the Balinese tribe can be seen in the mandible.

The effect of 4 first premolar extractions on the posterior Bolton ratio

Overall and anterior Bolton ratios have been well covered in the orthodontic literature; however, little has been reported on posterior Bolton ratios. Considering the frequency of premolar extractions in the specialty, it would be relevant to know how the posterior occlusion is affected by premolar extractions. This study aimed to investigate how the posterior Bolton ratio is affected by the extraction of the 4 first premolars. Fifty-five patients with Class I occlusion within 1 standard deviation of ideal anterior and overall Bolton ratios models were selected and digitized. Tooth widths were measured. Virtual extractions of 4 first premolars were performed, and a digital setup of anterior and remaining posterior teeth observing ideal occlusion relationships was executed. When space closure compromised the occlusion, preference was given to the latter. Residual interproximal spacing was digitally measured on the setups. Analysis of variance and linear regression tests were used to identify factors contributing to interproximal spacing. An average of 1.1mm of net residual spacing between mandibular second premolars and first molars was observed. In 27% of the sample, at least 1.5mm of residual space was found. In addition, 16% showed at least 2mm of residual space. The ratio of the maxillary second premolars to the mandibular second premolars and the width of the maxillary second premolars best explain residual space (r=0.554; r2=0.307). A regression equation for predicting residual space is offered. Ideal anterior, posterior, and overall Bolton ratios treated with extraction of 4 first premolars and ideal occlusion will likely finish with some spacing in the mandible.

The Assessment of Fixed Orthodontic Treatment Successfulness Using American Board of Orthodontics System in Airlangga University Dental Hospital

Background: The purpose of orthodontic treatment is to improve efficient function, tissue balance, and obtain harmonious facial aesthetic results so the successfulness of orthodontic treatment should be comprehensive because maloclusion can occur in dentoalveolar, skeletal and soft tissue tissues. Purpose: This study aims to evaluate the successfulness of orthodontic treatment using fixed orthodontic appliances in Orthodontic Clinic Dental Hospital, Faculty of Dental Medicine Universitas Airlangga by means of ABO system. Methods: Descriptive analytic by comparing the data before and after treatment, then the sample was divided into 3 based on the skeletal malocclusion group. Dental efficacy was measured using the ABO system and the Bolton anterior ratio. Skeletal success by looking at ANB, FHI, and proportion of anterior facial height (UAFH: LAFH). Meanwhile, the success of the soft tissue was by seeing the changes in the aesthetic lines of the upper and lower lips. The statistics used in this study were Kruskal-Whallis for the ABO DI and OGS difference test, Spearman to determine the relationship between ABO DI and OGS measurement components and McNemar and Wilcoxon to determine the difference before and after treatment on all measurements. Results: Treatment of class I skeletal malocclusion had the best mean ABO OGS score. Class II and III treatments had significant treatment advancements. In other measurements, there are significant differences after treatment at FHI in class I, (UAFH: LAFH) in class II and lower lip esthetic line in class II. Conclusion: Generally, the successfulness of orthodontic treatment in Orthodontic Clinic Dental Hospital, Faculty of Dental Medicine, Universitas Airlangga was adequate. In addition, the assessment of the successful orthodontic treatment needs to be adjusted to the standard values that can be accepted by a certain population, especially the Javanese population.

Associations between Bolton ratio and overjet deviations in a Finnish adult population

Objective To determine the anterior Bolton ratio for a Finnish adult population and to investigate its associations with overjet. Material and methods This study is part of the Northern Finland Birth Cohort 1966. Clinical oral investigations, including three-dimensional intraoral scanning and registration of occlusion, were performed in connection with the 46-year follow-up for 1,961 subjects. Subjects with normal occlusion (n = 149), extreme overjet ≥ 8 mm (n = 49), large overjet 6–7 mm (n = 86), and negative overjet (n = 16) and no orthodontic treatment history were selected for further analysis. The mesiodistal widths were measured from canine to canine to evaluate the anterior Bolton ratio. Results A mean anterior Bolton ratio of 78.6 (SD 3.1) was found for the normal occlusion group. Subjects with extreme overjet had smaller Bolton ratios compared to the normal occlusion group and the negative overjet group (p = .005, p = .019, respectively). Overjet deviations were associated with upper canine and incisor widths. Conclusions The mean anterior Bolton ratio in subjects with normal occlusion was larger compared to the original Bolton ratio. Tooth size discrepancy was associated with extreme and negative overjet at population level.

The Difference of Mesiodistal Tooth Size Ratio Using Bolton Analysis for Palembang and Toba Batak Ethnicities

Introduction. Bolton's analysis is often used to determine discrepancy in tooth size. Mesiodistal size of teeth in each race &amp; ethnicity is different, resulting in a different ratio of mesiodistal teeth size. The mesiodistal tooth size ratio is very important in determining the orthodontic treatment plan so that a good occlusion can be achieved as the end result of treatment. The purpose of this study was to determine the difference in the ratio of mesiodistal teeth size between Palembang and Batak Toba ethnic according to Bolton's analysis.Methods. This is a cross-sectional analytic study. The number of participants was 60 subjects divided into 2 groups, Palembang and Batak Toba ethnicity (n=30). All samples consisting of the maxilla and mandible study cast from each participant then were measured the mesiodistal size ratio of the teeth using Bolton's analysis with Sliding Caliper. The data were analyzed using an independent T-test. Results. The results of this study indicate that there is no significant difference between the ratio of mesiodistal tooth size according to Bolton's analysis of the ethnic Palembang and Batak Toba both in the anterior ratio and the overall ratio. Only the anterior ratio of the Toba Batak ethnic group has a significant difference with the Bolton anterior ratio.Conclusion. The Bolton overall ratio (91.3) can be used for the Palembang and Toba Batak ethnic groups in Palembang, while the Bolton anterior ratio (77.2) can only be used for the Palembang ethnic group and cannot be used for the Toba Batak ethnic group in Palembang.

Accuracy and Reliability of Space Analysis Measurements in Digital Models with Different Degrees of Crowding

Background: With the introduction of digital systems in the orthodontic field, it is not still clear if such systems can accurately substitute analogical systems in the diagnosis and orthodontic treatment plane. Objective: The study compared the Arch Length Discrepancy (TALD) and Bolton ratio obtained from plaster dental casts (gold standard) and digital models and tested the null hypothesis that TALD and Bolton ratio measurements in digital models are affected by the degree of crowding. Methods: The sample included 40 dental models divided into five sub-groups, according to the American Board of Orthodontists (ABO) score of crowding. Plaster casts were scanned by a 3D laser scanner to obtain digital models. In digital and plaster models, the mesiodistal width of each tooth and arch lengths (maxillary and mandibular) were measured to calculate anterior and total Bolton ratios and TALD. Three operators performed measurements on plaster and digital models using a digital caliper and OrthoAnalyzerTM 3D software (3Shape A/S, Copenhagen, Denmark). Results: No statistically significant differences were obtained for intra and inter-examiner reliability (p &gt; 0.05). When comparing plaster and digital findings, statistically significant differences were obtained for all measurements except for mandibular arch length and anterior Bolton ratio. In general, there was an overestimation of tooth size and arch length discrepancy in digital models. Moreover, the mean difference of measurements between both the methods increased in more crowded models. Conclusions: Crowding affects, the accuracy of Bolton ratio, and the arch length measurements. since the overestimation is relatively small, it should not be considered of clinical significance.

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.

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.

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.