Relationship between vertical facial morphology and dental arch measurements in class II malocclusion: a retrospective study

Background

To evaluate the relationship between dental arch measurements and the vertical facial pattern determined in skeletal Class II untreated patients.

Methods

Lateral cephalograms and plaster models were obtained from 124 untreated female adults (average age: 17.6 ± 3.8 years). Class I (CI), Class II Division 1 (CII/1) and Class II Division 2 (CII/2) malocclusions were divided into three subgroups according to their vertical morphology as hypodivergent, normodivergent and hyperdivergent. The multivariate variance analysis (MANOVA) method was used in the comparison of measurement values according to vertical and sagittal morphology. The relationship between both A point-Nasion-B point (ANB) and Frankfurt-mandibular plane (FMA) angles and dental arch measurements was examined by Pearson correlation analysis. The significance level was received as p < 0.05.

Results

While vertical morphology has a statistically significant effect on mandibular arch length, sagittal morphology affects maxillary arch depth. The parameters influenced by both morphologies are maxillary and mandibular arch length, as well as maxillary intermolar width. The mandibular arch length was significantly shorter in hyperdivergent-CII-2 malocclusion (50.5 ± 7.4 mm). Larger values were obtained in both mandibular arch length and maxillary arch depth measurements in CII-1 malocclusion compared to CII-2 malocclusion. The maxillary intermolar width was significantly shorter in hypodivergent-CII-1 malocclusion (46.8 ± 3.4 mm), while it was higher in hypodivergent-CI malocclusion (51.1 ± 3.4 mm). The maxillary arch length was the lowest in hyperdivergent-CI malocclusion (63.1 ± 13.3 mm) and the highest in hypodivergent-CI malocclusion (72.8 ± 7.6 mm). Additionally, a positive but weak correlation was found between ANB and FMA angles.

Conclusion

Dental arch measurements have been found to be affected by both vertical facial morphology and skeletal sagittal relationship. A positive correlation was found between ANB and FMA angles.

Assessment of Dental Arch Parameters in Turkish Twins

BACKGROUND

The aim of this study is to investigate the relative contributions of genetic and environmental factors to variations in dental dimensions in a sample of Turkish twins, and to estimate heritability using dental casts.

STUDY DESIGN

The study samples were selected from the twin children between 3-15 years old who referred for their first dental examination. Fifty nine monozygotic and one hundred and forty three dizygotic twin pairs were examined in the study. The alginate impression material used to create the plaster model of maxilla and mandible. Anterior arch width, posterior arch width, arch length and arch circumference were measured on models prepared from measurements taken for both maxilla and mandible with digital caliper. The similarities and differences of the measurements were compared between pairs of twins and zygocytes. Morever, the effects of bad oral habits, bruxism, a result of psychosocial factors on measurements were examined. Statistical analysis was performed using Paired T Test, Wilcoxon Test and Mann Whitney U test.

RESULTS

A total of 404 dental models of 118 (29.2%) monozygotic and 286 (70.8%) dizygotic twins were evaluated. There was no statistical difference between sibling pairs in both monozygotic and dizygotic twins. The measurement similarity between twin siblings differed according to zygosity in all measurements (p<0.05). It has been observed that the finger sucking and mouth breathing affect the dental arch measurements (p<0.05).

CONCLUSION

These results indicate that the differences in dental arch dimensions between monozygotic twin pairs are less than the difference between dizygotic twin pairs.

Assessment of Dental Arch Parameters in Turkish Twins

BACKGROUND

The aim of this study is to investigate the relative contributions of genetic and environmental factors to variations in dental dimensions in a sample of Turkish twins, and to estimate heritability using dental casts.

STUDY DESIGN

The study samples were selected from the twin children between 3-15 years old who referred for their first dental examination. Fifty nine monozygotic and one hundred and forty three dizygotic twin pairs were examined in the study. The alginate impression material used to create the plaster model of maxilla and mandible. Anterior arch width, posterior arch width, arch length and arch circumference were measured on models prepared from measurements taken for both maxilla and mandible with digital caliper. The similarities and differences of the measurements were compared between pairs of twins and zygocytes. Morever, the effects of bad oral habits, bruxism, a result of psychosocial factors on measurements were examined. Statistical analysis was performed using Paired T Test, Wilcoxon Test and Mann Whitney U test.

RESULTS

A total of 404 dental models of 118 (29.2%) monozygotic and 286 (70.8%) dizygotic twins were evaluated. There was no statistical difference between sibling pairs in both monozygotic and dizygotic twins. The measurement similarity between twin siblings differed according to zygosity in all measurements (p<0.05). It has been observed that the finger sucking and mouth breathing affect the dental arch measurements (p<0.05).

CONCLUSION

These results indicate that the differences in dental arch dimensions between monozygotic twin pairs are less than the difference between dizygotic twin pairs.

Comparative Study of Tooth Size and Arch Dimensions in Class I Crowded, Proclined Malocclusion and Class I Normal Occlusion

Aim

The objectives are to compare the extent and to find whether it is arch dimension or tooth size that contributes to a greater extent to malocclusions such as dental crowding and proclination.

Materials and Methods

A total of 90 pretreatment models were selected and divided into three groups, namely uncrowded (Group-A), crowded (Group B), and proclination (Group-C). Measurements obtained were: (1) The largest mesiodistal width of each tooth on each arch (except the second and third molars), (2) Buccal inter-canine and inter-molar widths, (3) Lingual inter-canine and inter-molar widths, (4) Arch perimeters, and (5) Arch length.

Results

The mesiodistal teeth dimensions were higher in crowded and proclination group. Both inter canine width and inter molar width of maxilla were reduced in crowded group. Maxillary and mandibular arch perimeter and arch lengths were higher proclination group.

Evaluation of Dental Crowding and Spacing in Relation to Tooth Size and Arch Dimensions in a Sample of Sudanese Adults

AIMS AND OBJECTIVES

This study aimed to compare tooth size and arch dimensions between normal, crowded, and spaced groups in a Sudanese sample.

MATERIAL AND METHODS

A sample of 312 university students, were selected and divided into normal, crowded, and spaced groups. Each group included 104 students with equal males to females ratios. Age was ranged from 16 to 26 years. Mesiodistal (MD) tooth width of all teeth (except molars), arch perimeters, and dimension at the level of intercanine, interpremolar, and intermolar were measured for each group. ANOVA and student t-test were performed for the comparison between groups.

RESULTS

The MD dimensions of all teeth are greater in crowded arches as compared to the teeth in normal dental arches, except for the width of the maxillary, left second premolar in females, and mandibular left second premolar in male. Spaced arches were presented with significantly smaller MD width in all teeth when compared to normal arches, except for the width of maxillary right second premolar, maxillary left first premolar, mandibular right and left second premolars in female, and maxillary right second premolar in male. Crowded arches exhibit the largest total tooth material followed by normal and spaced dentition. Spaced arches show the widest arch dimension and perimeters followed by normal and crowded dentitions.

CONCLUSIONS

Both tooth size and arch dimensions contribute to dental crowding and spacing.

CLINICAL RELEVANCE

Since the size of the teeth and dental arches affect the space availability of the dentition. These factors should be considered in the initial stages of orthodontic treatment planning to avoid compromised treatment outcomes.

Morphological and dimensional characteristics of dental arch in children with beta thalassemia major

BACKGROUND AND OBJECTIVES

The aim of this study was to examine the arch dimensions of beta thalassemia major patients in comparison with normal individuals.

MATERIALS AND METHODS

Dental arch dimensions were compared between thalassemic patients and normal individuals in the age group of 12-16 years in the maxillary and mandibular arch corresponding to each other regarding age, sex and Angle's molar relationship. A total number of sixty cases in each group were taken. Maxillary and mandibular impressions were made with alginate for all the sixty participants in each group and poured with die stone. Measurement of inter incisor, inter canine, inter premolar and intermolar arch width, arch depth, right anterior, right posterior, left anterior, and left posterior arch length was carried out from each cast using digital Vernier caliper.

RESULTS

Unpaired t-test was used for comparison between the two groups. Statistically, a significant difference was found between the case and control groups in the maxillary arch in intercanine width, inter premolar width, intermolar width, right anterior arch length, right posterior arch length, and left anterior arch length. However, no statistically significant difference was found between the groups in inter incisor width, left posterior arch length, and arch depth in the maxillary arch. In the mandibular arch, statistically significant difference was found between the case and control groups in inter canine width, inter premolar width, inter molar width, and left anterior arch length. However, no statistically significant difference was found between the case and control groups in the mandibular arch in interincisor width, right anterior arch length, right posterior arch length, and left posterior arch length.

CONCLUSION

Dental arch widths and arch lengths were significantly reduced in thalassemic patients as compared to normal individuals for the maxillary and mandibular arches.

Comparison of arch form between ethnic Malays and Malaysian Aborigines in Peninsular Malaysia

Objective

To determine and compare the frequency distribution of various arch shapes in ethnic Malays and Malaysian Aborigines in Peninsular Malaysia and to investigate the morphological differences of arch form between these two ethnic groups.

Methods

We examined 120 ethnic Malay study models (60 maxillary, 60 mandibular) and 129 Malaysian Aboriginal study models (66 maxillary, 63 mandibular). We marked 18 buccal tips and incisor line angles on each model, and digitized them using 2-dimensional coordinate system. Dental arches were classified as square, ovoid, or tapered by printing the scanned images and superimposing Orthoform arch templates on them.

Results

The most common maxillary arch shape in both ethnic groups was ovoid, as was the most common mandibular arch shape among ethnic Malay females. The rarest arch shape was square. Chi-square tests, indicated that only the distribution of the mandibular arch shape was significantly different between groups (p = 0.040). However, when compared using independent t-tests, there was no difference in the mean value of arch width between groups. Arch shape distribution was not different between genders of either ethnic group, except for the mandibular arch of ethnic Malays.

Conclusions

Ethnic Malays and Malaysian Aborigines have similar dental arch dimensions and shapes.