Evaluation of Interradicular Distances in the Mandible and their Correlation to Dental Crowding for Orthodontic Miniscrew Insertion Among Yemeni Adults

Abstract

The success of orthodontic treatment depends mostly upon the availability and management of anchorage, hence the need for anchorage devices such as miniscrews. The accurate assessment of interradicular distance (IRD) is important for safe orthodontic miniscrew insertion, especially in the mandible where root proximity may increase the risk of iatrogenic injury. However, it has been unclear whether the severity of mandibular dental crowding can be used as a clinical indicator of available interradicular space and no research had attempted to create a miniscrew insertion “safe zone” map for Yemeni adults. Therefore, this study aimed to investigate the correlation between dental crowding and mandibular IRD using cone beam computed tomography (CBCT) in a sample of Yemeni adults. A total of 60 Yemeni adults aged 18 to 35 years were included and equally distributed into three groups according to the severity of mandibular crowding: mild, moderate, and severe. Dental crowding was measured on study casts using tooth size–arch length discrepancy analysis, while mandibular IRD was measured on CBCT images at the vertical levels 2, 4, 6, and 8 mm apical to the cementoenamel junction. The statistical analyses used in this study included one-way ANOVA, Pearson’s chi-square test for baseline comparability, intraclass correlation coefficient (ICC) for reliability, Wilcoxon signed-rank test for right –left comparisons, Kruskal–Wallis test for comparisons among crowding groups, and Spearman’s rank correlation coefficient for correlation analysis, along with Bonferroni correction for multiple comparisons. The intra-examiner reliability was predominantly good to excellent. The results showed that the three groups were comparable in age and sex distribution. All interradicular measurements showed no statistically significant differences among the three crowding groups (all p > 0.05). Using the calculated mean value a preliminary map of site favorability for the insertion of miniscrew in the mandible was concluded from this Yemeni adult sample which indicates that the posterior region is safer for miniscrew insertion than the anterior region. In conclusion, no significant correlation was found between mandibular dental crowding severity and IRD. Therefore, dental crowding severity should not be used as a predictive factor for the availability of interradicular distance.