Tooth Size Discrepancy Research Articles

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.

Evaluation and comparison of tooth size discrepancies among different malocclusion groups

Evaluation and comparison of tooth size discrepancies among different malocclusion groups

The British Orthodontic Society MOrth cases prize 2014.

This paper describes the orthodontic treatment of two cases that were successful in winning the British Orthodontic Society (BOS) Membership in Orthodonitcs (MOrth) cases prize in 2014. The first case describes the management of a 26-year-old female with a Class II division 2 incisor relationship on a Class III skeletal base with reduced vertical proportions. This was complicated by: an unerupted ectopic palatally displaced upper right permanent canine, an erupted palatally displaced upper left permanent canine, retained deciduous canines, generalised microdontia, an overall Bolton tooth size discrepancy, mild crowding in the upper arch, an increased overbite (complete to tooth tissue) and crossbites. Treatment involved a surgical exposure of the ectopic canine and the use of fixed pre-adjusted edgewise appliances over a period of 24 months. The second case describes the management of a 12-year-old female with a Class II division 2 incisor relationship on a Class 2 skeletal base with reduced vertical proportions. This was complicated by: an increased overjet and overbite (complete to soft tissue), mild upper and lower arch crowding and an increased naso-labial angle. Treatment involved an initial phase of modified Clark Twin Block and sectional fixed appliances followed by complete fixed pre-adjusted edgewise appliances over a period of 24 months.

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.

Relationship of bolton’s ratios and tooth-size discrepancy

Relationship of bolton’s ratios and tooth-size discrepancy

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.

Tooth Size Discrepancy Importance as a Diagnostic Tool for Orthodontic Treatment Planning : A Review

The main goal in comprehensive orthodontic treatment is to obtain an optimal functional occlusion, overbite and overjet. Tooth size discrepancies of the maxillary and the mandibular arches are an important factor for achieving this goal. Inadequate relationships between the maxillary and the mandibular teeth can pose problems in achieving the ideal occlusion. Early treatment planning and proper diagnosis of tooth size discrepancy minimizes problems attained at finishing stage. Bolton’s ratios set an ideal relationship of maxillary tooth width to mandibular tooth width. This article shows the significance, validity as a diagnostic tool and the methods of measuring tooth size discrepancy. Resume Le principal objectif du traitement orthodontique est d’obtenir une occlusion fonctionnelle, un recouvrement et un surplomb optimaux. La difference dans la taille entre dents maxillaires et dents mandibulaires est un facteur important pour la realisation de cet objectif. Les rapports inter-arcades inadequats peuvent poser des problemes dans la realisation de l’occlusion ideale. La planification du traitement et le diagnostic correct de la difference des dimensions des dents reduisent les problemes au stade final du traitement. Le rapport de « Bolton » etablit une relation ideale entre la largeur des dents maxillaires et celle des dents mandibulaires. Cet article montre l’importance et la validite des methodes de mesure de la divergence des tailles des dents.

Think Laterally, Go Mathematically: An Innovative Way to Calculate Bolton's Discrepancy in Cases with Impacted or Congenitally Missing Teeth

The incidence of impacted teeth and congenitally missing teeth is fairly increasing. For the achievement of an ideal occlusion and a good intercuspation, we need to identify the interarch tooth size discrepancy. But in cases with unerupted and missing tooth, considering the tooth size of the missing tooth is questionable. Thereby, we have proposed a mathematical concept for the calculation of the mesiodistal width of the missing tooth. The use of this method in our department is a testimony of its usefulness.

Management of tooth size discrepancy due to previously extracted maxillary canines

Management of tooth size discrepancy due to previously extracted maxillary canines

Smile Redesigned – A Case Report

Introduction Tooth size discrepancy or uneven spacing between the anterior teeth is a major aesthetic problem for patients. Closure of these interdental spaces using resin composite offer to be a more conservative and practical approach. Direct composite restoration has several distinct advantage

Association between Bolton discrepancy and Angle malocclusions.

This study aimed to assess and compare the overall and anterior ratios of tooth size discrepancies in all Angle malocclusion groups. The following null hypothesis (H0) was tested: no difference between tooth size discrepancies (overall and anterior) would be observed among Angle malocclusion groups. The sample comprised of 711 pre-orthodontic treatment study casts of Brazilian patients with a mean age of 17.42 years selected from private practices in Brazil. The casts were divided into 3 groups according to the type of malocclusion: Class I (n = 321), Class II (n = 324), and Class III patients (n = 66). The measurement of the greatest mesiodistal width of the teeth was performed using a centesimal precision digital caliper directly on the study casts, from the distal surface of the left first molar to the distal surface of the right first molar. The overall and anterior ratios between the maxillary and mandibular teeth were evaluated using Bolton's method. The following statistical tests were applied: chi-square, independent t-test, and one-way ANOVA. Results showed that all Angle malocclusions groups exhibited a ratio compatible with those recommended by Bolton. With respect to the overall and anterior ratios among the malocclusion groups, no statistically significant differences were found. The null hypothesis was accepted because the results showed no differences in the overall and anterior ratios of tooth size discrepancies among different Angle malocclusion groups.

Maxillary lateral incisor agenesis and its relationship to overall tooth size

Statement of problemAgenesis of the maxillary lateral incisor has been linked to differences in the size of the remaining teeth. Thus, the mesiodistal space required for definitive esthetic restoration in patients with missing maxillary lateral incisors may be reduced. PurposeThe purpose of this study was to determine whether a tooth size discrepancy exists in orthodontic patients with agenesis of one or both maxillary lateral incisors. Material and methodsForty sets of dental casts from orthodontic patients (19 men and 21 women; mean 15.9 years of age; all of European origin) were collected. All casts had agenesis of one or both maxillary lateral incisors. Teeth were measured with a digital caliper at their greatest mesiodistal width and then compared with those of a control group matched for ethnicity, age, and sex. Four-factor ANOVA with repeated measures of 2 factors was used for statistical analysis (α=.05). ResultsOrthodontic patients with agenesis of one or both maxillary lateral incisors exhibited smaller than normal tooth size compared with the control group. The maxillary arch had a larger tooth size difference between the control and test groups than the mandibular arch (there was a significant Jaw×Group interaction [F=4.78, P=.032]). ConclusionsAgenesis of one or both maxillary lateral incisors is significantly associated with tooth size discrepancy, which may affect the space remaining for restoration of the remaining teeth.

Management of tooth size discrepancy due to previously extracted maxillary canines

This case report is of a patient whose maxillary canines had been previously extracted. She complained of severe crowding in the lower arch. Intraoral examination revealed that she had Class I molar relationship, nonocclusion in the premolar region, and cross bite. Cast analysis showed tooth size/arch length discrepancy in the lower arch and Bolton's tooth size analysis showed large mandibular excess. Treatment included extraction of mandibular first premolars and fixed mechanotherapy to correct crowding, canine relation, and Bolton's discrepancy. Maxillary premolars were substituted for the extracted canines. At the end of treatment, the patient had a pleasing profile, good intercuspation, ideal overjet, and overbite. Posttreatment cephalometric evaluation showed acceptable maxillary and mandibular incisor inclinations. The occlusion remained stable after orthodontic treatment.

Missing or Extraction of a Mandibular Incisor in Orthodontics

The extraction of a mandibular incisor constitutes a non-conventional alternative in treating certain anomalies. It is not a standard approach to symmetrically treating most malocclusions, but in some clinical situations the therapeutic aim must be adjusted to individual patient needs, even when this means that achieving final occlusion is not ideal. This treatment option may be indicated in malocclusions with anterior tooth size discrepancy due to narrow maxillary incisors and/or large mandibular incisors. It is contraindicated in malocclusions without anterior discrepancy or with discrepancies caused by large maxillary incisors and/or narrow mandibular incisors. The literature suggests that this method affords improved post-treatment stability compared with premolar extraction. A careful diagnosis, established with the aid of a diagnostic setup, professional skills and clinical experience are instrumental in achieving successful orthodontic results with this treatment option. The deliberate extraction of a mandibular incisor in certain cases allows the orthodontist to improve occlusion and dental esthetics. This article highlights the importance, indication, contraindications, advantages, disadvantages and stability of the results achieved in treatments performed with mandibular incisor extraction. Two clinical cases are presented illustrating the modality of such a treatment.

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.

Evolution of treatment mechanics and contemporary appliance design in orthodontics: A 40-year perspective.

Until the early 1970s, successful treatment with the Begg technique and the Tweed edgewise technique required tedious wire bending. The introduction of Andrews' straight wire appliance changed that, and it was one of the most significant contributions in the history of orthodontics. The straight wire appliance significantly reduced the amount of wire bending and also brought along other options in treatment mechanics. Retraction of the canines with elastic chains and ligature wires became more common. Sliding mechanics in place of closing loops became the method of space closure for a significant number of clinicians. Edgewise force levels were initially used to close spaces; however, it was soon observed that lighter forces were more effective with sliding mechanics. Along with these changes, it became apparent that compensation in the appliance was needed, depending on the type of malocclusion and particularly with varying extraction sequences. Various appliance designs were developed to accommodate changes in mechanics and force levels. These modifications improved tooth positions at the end of treatment as long as the brackets were properly placed. These major changes in appliances, force levels, and treatment mechanics can be traced back to the work of Dr Lawrence Andrews and the straight wire appliances.

Biometric analysis of the clinical crown and the width/length ratio in the maxillary anterior region

Statement of problemRestorative dentistry often involves correcting tooth size discrepancies. Therefore, dental biometrics should play an important role in the planning of an esthetic restoration. PurposeThe purpose of this study was to analyze the clinical crown width, length, and width/length ratio of maxillary central incisors, lateral incisors, and canines in an adult population. The study also aimed to determine whether a correlation exists between natural tooth dimensions and the optimal tooth dimension guidelines suggested for planning esthetic restorations. Material and methodsStone casts were poured from irreversible hydrocolloid impressions of 412 healthy adult participants. These casts were used to measure the maximum mesiodistal width and maximum crown-root length of the maxillary central incisors, lateral incisors, and canines with a digital precision caliper (0.01 mm). The width/length ratio was calculated for each tooth, and 40 casts were selected to test the reliability of the measuring method. ResultsThe mean age of the participants in the sample was 33.94 years; 60.7% were women and 39.3% were men. The mean width value was 8.71 mm for central incisors, 6.75 mm for lateral incisors, and 7.81 mm for canines. The mean length was 10.23 mm for central incisors, 8.59 mm for lateral incisors, and 9.93 mm for canines. The average width/length ratio was 85% for central incisors and 79% for lateral incisors and canines. ConclusionThe data obtained from the population studied are similar to those from previous research studies with similar methodology. However, great discrepancies in the absolute values were found when compared with other studies of ideal tooth dimension guidelines on the personal preferences and the esthetic perception of dentists. The perception of what is considered natural seems to differ from what is considered esthetically perfect.

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.

Evaluation of the mandibular arch in patients with impacted permanent lower canines

Abstract Aim To determine the features of the mandibular dental arch in subjects presenting with impacted permanent lower canines. Methods The ‘impaction group’ consisted of 48 Indian subjects with mandibular canine impaction (Females:Males, 1.5:1; mean age, 15.03 ± 0.49 years). The ‘control group’ was comprised of 96 age-, gender- and malocclusion-matched Indians who were randomly selected from subjects initially screened but who had completely erupted mandibular canines. Arch width, arch length, arch shape and space status (total tooth size, arch-length – tooth-size discrepancy) were assessed using dental models and were compared between the groups using comparative measurements and statistics. Results Statistically significant differences were demonstrated with respect to the arch length, arch shape, total tooth size and arch-length – tooth-size discrepancy (p = 0.03, 0.02, 0.04, 0.01; independent 2-sample t-tests, respectively). Crowding was more prevalent in subjects with impaction than in the controls, with the difference being statistically significant (chi-square = 13.202; degrees of freedom (df) = 4; p = 0.010). Conclusion Patients with permanent mandibular canine impaction have adequately wide but shorter lower dental arch forms along with wider mandibular total tooth size and greater arch-length – tooth-size discrepancy when compared with a control sample.

An evaluation of tooth size discrepancies among different malocclusion groups in North Indians

Objective: A study was conducted to evaluate tooth size discrepancies among different malocclusion groups. Materials and Methods: This study consisted of 160 North Indian subjects, 50 normal occlusion group and 110 subjects with varying degree of malocclusion, that is, Angle's Class I (40), Class II Division 1 (40) and Class III (30) malocclusion, respectively. Tooth size measurements were performed on the study models by using a digital Caliper with a liquid crystal display digital output to the nearest 0.01 mm, and various inter-arch ratios were analyzed. Statistical Analysis: One-way analysis of variance was used to analyze the difference in groups followed by Tukey post hoc test. Chi-square test was performed to demonstrate the prevalence of tooth size discrepancies among three malocclusion groups. Results: Significant differences were found for inter-arch ratios between the groups. Conclusions: Anterior, overall, and posterior ratios were higher in Class III followed by Class I and Class II Division 1 malocclusion, respectively. Anterior and overall tooth size discrepancy was found to be 20% and 17.2%, respectively, in the malocclusion sample.