A population-based survey on interarch malocclusion and background determinants

Background

Genetics, environment, and ethnic factors are major contributors to the prevalence and variations of malocclusion.

Aim

The aim of study was to determine the prevalence of interarch problems in school-aged children, 9 - 11 years, living in Tehran; and to describe the role of ethnicity, education, and economic status on them.

Methods

The present data were part of the Comprehensive Evaluation of Skeleto-Dental Anomalies (CESDA) study conducted in 2015 among children living in Tehran, Iran. Cluster random sampling was applied among 19 districts of Tehran. A total of 38 schools were selected, and out of 1585 participants, the data of 1429 children were collected (response rate = 90%). The Chi-square test and binary logistic regression analysis were used for statistical analyses.

Results

Of all participants, 758 were boys and 671 were girls. The mean age was 121 ± 8 months. The most significant background determinants associated with molar relationship were ethnicity and place of residence. Class I right molar relationship was seen in 57.9% of the children and was generally more frequent in boys. Normal overjet was observed in 47.1%; 41.5% had an increased overjet, 16.2% had an anteroposterior cross-bite, and 11.8% had a lateral cross-bite. Midline discrepancy was seen among 61.1% of the children. Ideal anteroposterior, vertical, and horizontal relationship were observed in 31%, 53%, and 34% of the children, respectively. Only 10% of the children aged 9 - 11 years old had an ideal interarch relationship. Gender and place of residence had persistently significant association with having an ideal anteroposterior, vertical, horizontal, and interarch relationships (P < 0.002) in all four binary logistic regression models.

Conclusions

The majority of the children aged 9 - 11 years old have at least one interarch problem, although it is commonly preventable.

Relevance for Patients

Early detection of children's orthodontic problems may help with effective prevention of further advanced anomalies.

Association between Chewing Side Preference and Dental Caries among Deciduous, Mixed and Permanent Dentition

INTRODUCTION

Chewing Side Preference (CSP) is said to occur when mastication is recognized exclusively/consistently or predominantly on the same side of the jaw. It can be assessed by using the direct method - visual observation and indirect methods by electric programs, such as cinematography, kinetography and computerized electromyography.

AIM

The present study was aimed at evaluating the prevalence of CSP in deciduous, mixed and permanent dentitions and relating its association with dental caries.

MATERIALS AND METHODS

In a cross-sectional observational study, 240 school going children aged 3 to 18years were randomly allocated to three experimental groups according to the deciduous dentition, mixed dentition and permanent dentition period. The existence of a CSP was determined using a direct method by asking the children to chew on a piece of gum (trident sugarless). The Mann Whitney U-test was used to compare the CSP and also among the boys and girls. The Spearman's Correlation Coefficient was used to correlate CSP and dental caries among the three study groups and also among the groups.

RESULTS

CSP was observed in 69%, 83% and 76% of children with primary, mixed and permanent dentition respectively (p>0.05). There was no statistically significant association between the presence of CSP and dental caries among the three study groups.

CONCLUSION

There was a weak or no correlation between gender and distribution of CSP and between presence of CSP and dental caries.

Reliability of permanent mandibular first molars and incisors widths as predictor for the width of permanent mandibular and maxillary canines and premolars

AIM

Preventive measures are necessary to prevent a potential irregularity from progressing into a more severe malocclusion. The determination of the tooth size-arch length discrepancy in mixed dentition requires an accurate prediction of the mesiodistal widths of the unerupted permanent teeth.

MATERIALS AND METHODS

For the study, 200 subjects in the age group of 16-25 years were selected from various colleges of M. M. University. The mesiodistal width of permanent mandibular incisors, first molars, canines and premolars of both arches were measured on the subject cast using an electronic digital caliper. Statistical analysis showed a significant difference between mesiodistal tooth widths of males and females. Linear regression equation was determined to predict the sum of mandibular and maxillary permanent canines and premolars using mandibular first molars plus the four mandibular incisors as predictors.

RESULTS

There was no significant difference between the actual and predicted width of sum of permanent canines and premolars using regression equations. The predicted widths of both arches using Tanaka and Johnston equations showed significant differences. Determined regression equations for males were accurate in male samples and determined regression equation for females were accurate in female samples for both arches.