Intermaxillary Tooth Size Discrepancies Research Articles

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

In the mixed dentition period, malocclusion is in dormant stage, any interception should be preceded by a mixed dentition space analysis. To derive new regression equation in sample subjects (indigenous group) with no intermaxillary tooth size discrepancy (Bolton's ratio) residing in Davangere and to evaluate its accuracy. To assess the difference of tooth dimensions between males and females and difference between right and left of dental arches. Descriptive study. One hundred and fifty children (11-15 years) were included and dental casts were made. A digital Vernier caliper was used for the measurement of teeth. Bolton's ratio was calculated. Group A: Casts without Bolton's discrepancy and Group B: Casts with Bolton's discrepancy. The data were analyzed with the SPSS software version 22.0. New regression equations were derived using correlation and regression analysis. No statistically significant difference was recorded between the actual and predicted mesiodistal widths (MDWs) of permanent canine and premolars in maxilla and mandible, with/without Bolton's discrepancy. Males had statistically significant higher mean in maxillary and mandibular canine dimensions than female and no statistically significant difference between right and left side of dental arches was found. New regression equation was formulated for Davangere population, in which actual and predicted widths of permanent canines and premolars were found to be almost similar when established from sample with/without Bolton's discrepancy. In MDWs, the canine showed significant sexual dimorphism and no clinically significant variations were seen in the right and left sides of both the arches.

Tooth size discrepancy in different malocclusion groups in Libya: a pilot study

Abstract Background: Orthodontists need to evaluate intermaxillary tooth size discrepancy (TSD) prior to initiating treatment in order to achieve a stable treatment. Thus, the aim of the present study was to determine the prevalence of TSD in Libyan subjects among different malocclusion groups. Methods: A sample of 60 dental casts of Libyan subjects with different types of malocclusions (Class I, Class II div 1 and Class III) were included in the study. Each malocclusion group (20 dental casts) included equal numbers of males and females, 12-17 years of age. Mesio-Distal tooth measurements were extracted to compute the anterior and overall TSD ratios. Paired Student t-test was used to detect significant discrepancies between the paired teeth measurements. Analysis of Variance (ANOVA) and Tukey Honestly tests were undertaken to detect significant discrepancies among the malocclusion groups. Results: Paired t-test revealed that there were no significant discrepancies between the paired tooth widths except for the upper first molars, upper first premolars, lower lateral incisors and lower canines (P<0.010). ANOVA found no significant differences in the mean anterior TSD ratio in regard to malocclusion groups. However, a significant disparity was noticed in the mean overall TSD ratio among the different malocclusion categories (P<0.04). Conclusion: Statistically significant TSD between the examined malocclusion groups were observed only in the mean overall TSD ratio.

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.

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.

Intermaxillary tooth-size discrepancies in different sexes, malocclusion groups, and ethnicities

To achieve proper occlusion, practitioners must consider tooth-size discrepancies between the jaws. Previous studies have shown considerable differences in tooth sizes between sexes, ethnicities, and malocclusion categories. The aim of this study was to compare mean tooth-size statistics between these groups, specifically determining a maxillary or a mandibular excess tooth-size discrepancy in clinically relevant cases. This study involved 306 subjects of varying sex, ethnicity, and malocclusion category, randomly chosen from the treatment population of the orthodontic clinic at the New Jersey Dental School, University of Medicine and Dentistry of New Jersey. The prevalence of discrepancies (±1 and 2 SD) between all groups and within groups was measured. Fifty percent of the subjects had anterior Bolton tooth-size discrepancies, and 41% had overall Bolton tooth-size discrepancies of ±1 SD. Tooth-size ratios compared with analysis of variance (ANOVA) showed no significant correlation between and among the sexes, ethnicities, and malocclusion groups. Compared with Caucasian and Hispanic patients, African-American patients had significantly greater odds of having a clinically significant (±2 SD) anterior ratio. When we compared the numbers of subjects above or below the clinically significant ratio, there was equal distribution of maxillary and mandibular excess in Class II and Class III patients. Caucasian and African-American patients had equal distributions of maxillary and mandibular excess, whereas Hispanic patients displayed a higher bias toward mandibular excess. Tooth-size discrepancies are common in orthodontic populations and are evenly distributed among sex, ethnicity, and malocclusion category, with some exceptions.

Intermaxillary tooth size discrepancies among different malocclusion groups

The aims of this study were to identify possible gender-related differences in tooth size ratios, to determine whether there is a prevalence for intermaxillary tooth size discrepancies in any malocclusion group, and to detect the percentage of tooth size discrepancies outside 1 or 2 standard deviations (SDs) from Bolton's mean. The material comprised the models of 500 subjects (284 females and 216 male aged between 12 and 28 years). Five groups were formed: normal occlusion, Class I, Class II division 1, Class II division 2, and Class III, which had an equal number of subjects. Tooth size measurements were undertaken using an electronic measuring device. Overall, anterior, and posterior ratios were computed as described by Bolton. For statistical evaluation, analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) tests were used. A significant gender difference was found only for posterior ratio in all groups (P < 0.01). There was no significant difference among the malocclusion groups in anterior ratio, but the differences for overall and posterior ratios were significant (P < 0.05 and P < 0.001, respectively). A large number of subjects had discrepancies greater than 2 SD from Bolton's mean. In addition, the means and SDs in this investigation were found to be larger than those of Bolton. Intermaxillary tooth size ratios may vary in different malocclusion types and may, to some degree, contribute to the severity of a malocclusion.

New regression equations for mixed-dentition arch analysis in a Turkish sample with no Bolton tooth-size discrepancy

Our objectives were to establish new regression equations derived from 228 Turkish patients (100 boys, 128 girls) with no intermaxillary tooth-size discrepancy that would give the greatest correlation coefficient for the sum of permanent tooth widths of the canines and the premolars of both jaws, according to sex, and to compare our new data with those from other studies. Mesiodistal tooth widths were measured from dental casts. Student t tests were carried out to compare tooth sizes between the sexes and the right and left sides of the arches. The constants a and b in the standard linear regression equation (y = a + bx), the correlation coefficients (r), the coefficients of determination (r2), and the standard errors of the estimates (SEE) were calculated. Statistically significant differences were found between the widths of teeth between the sexes in both the maxillary (P <0.01) and mandibular (P <0.001) arches. The r value was 0.956 to 0.989, with the higher coefficients in the girls. The r2 values were 91% in boys and 98% in girls, and the SEE was better in the maxilla and the mandible (0.013 mm) for the girls. The regression equations produced predictions of mesiodistal width summations for the maxillary and mandibular canine and premolar segments that were much different from other reported studies. New regression equations were derived for Turkish people. The prediction equations and probability tables should be revised by using subjects with no tooth-size discrepancy.

Intermaxillary tooth size discrepancy and mesiodistal crown dimensions for a Turkish population

The aims of this study were to determine the size of individual permanent teeth, tooth-size ratios for the maxillary and mandibular dentitions, and sex differences for those variables in a Turkish population, and to compare the figures obtained with those of the Bolton analysis. The data were derived from dental casts of 150 Turkish subjects (72 men, mean age 22.09 +/- 3.11 years; 78 women, mean age, 21.11 +/- 2.08 years) with normal occlusions. The mean, standard deviation, and minimum and maximum values were calculated for individual tooth size, and overall and anterior ratios, separately for men and women. To determine whether there are sex differences in intermaxillary tooth size discrepancies, an independent samples t test was performed. The mesiodistal dimensions of the maxillary teeth showed greater variability than the mandibular teeth, with the first molar dimensions having the greatest variability. The overall and anterior ratios were found to be 89.88 +/- 2.29 and 78.26 +/- 2.61, respectively. A statistically significant sex difference was found only in overall ratio (P < .001). According to Bolton's mean values, a discrepancy in the overall ratio was found in 18% of Turkish normal occlusion subjects, and anterior ratios outside 2 standard deviations from the Bolton mean were found in 21.3% of our sample. These findings indicate that population-specific standards are necessary for clinical assessments. Bolton's original data do not represent Turkish people, and therefore it is appropriate to use Turkish norms in daily orthodontic practice for Turkish patients.

Intermaxillary tooth size discrepancy and malocclusion: is there a relation?

The aims of this study were to identify the possible sex differences in tooth size ratios between males and females, to determine whether there is a difference in the incidence of tooth size discrepancies for both the anterior and overall ratios when comparing with Angle Class I; Class II, division 1; Class II, division 2; and Class III malocclusion groups, to compare the tooth size ratios of different malocclusion groups with the anterior and overall tooth size ratios of 150 untreated normal occlusion subjects. In addition, the aim was to determine the percentage of tooth size discrepancies outside 2 SD from Bolton means for tooth ratios present in each malocclusion group and in the overall sample of this study. This study consisted of 150 subjects who served as the normal occlusion group and 560 patients who showed four different malocclusion characteristics (Angle Class I; Class II, division 1; Class II, division 2; and Class III). Tooth size measurements were performed on the models of normal occlusion and pretreatment models. For statistical evaluation, Student's t-test, analysis of variance and Tukey Honestly Significant Difference tests were performed. A significant sex difference was found only in the overall ratio for normal occlusion subjects (P < .001). All malocclusion groups showed statistically significant higher overall ratios than the normal occlusion group (P < .001). There were no statistically significant differences among malocclusion groups; however, there were a large number of patients within each group who had discrepancies greater than 2 SD from the mean. Further investigations are needed to explain the probable racial differences and relationships between malocclusion and tooth size measurements.

Comparison of intermaxillary tooth size discrepancies among different malocclusion groups

The purpose of this study was to determine whether there is a prevalent tendency for intermaxillary tooth size discrepancies among different malocclusion groups. This study consisted of 60 subjects who served as the normal occlusion group and 300 patients divided into 5 malocclusion groups (ie, Class I with bimaxillary protrusion, Class II Division 1, Class II Division 2, Class III, and Class III surgery). Tooth size measurements were performed on the models of normal occlusion and pretreatment models of patients by the Three Dimension Measuring Machine. Moreover, tooth size ratios, analyzed as described by Bolton and the Student t test showed no sexual dimorphism for these ratios in each of 6 groups, so the sexes were combined for each group. Then these ratios were compared among different malocclusion groups. The results showed no significant difference between subcategories of malocclusion, so these groups were combined. There were now 120 cases in each of 3 categories: Class I, Class II, and Class III. A significant difference was found for all the ratios between the groups, the ratios showing that Class III > Class I > Class II. It demonstrated that intermaxillary tooth size discrepancy may be one of the important factors in the cause of malocclusions, especially in Class II and Class III malocclusions. Thus this study proved the fact that Bolton analysis should be taken into consideration during orthodontic diagnosis and therapy. (Am J Orthod Dentofacial Orthop 1999;116:539-44)