Contributory Factors of Mandibular Anterior Crowding in Early Mixed Dentition

Objectives: To evaluate the possible dentoskeletal factors contributing to mandibular anterior crowding in the early mixed dentition
Methods: There were carried out comparative analytical study design analysed mandibular dental casts and lateral cephalograms of 32 children in early mixed dentition were equally divided into two groups according to the severity of mandibular anterior crowding. On dental casts, space available for mandibular permanent incisors, total incisor width, total arch length, intercanine width, deciduous first intermolar width and permanent intermolar width and then on lateral cephalogram, anterior cranial base length, posterior cranial base length, maxillary length, mandibular length, Wits appraisal, SNA angle, SNB angle, ANB angle, upper incisor to NA angle, lower incisor to NB angle, interincisal angle, gonial angle, anterior cranial base to mandibular plane angle, Frankfort-mandibular plane angle and maxillo-mandibular plane angle were measured and compared between groups and correlations with crowding were investigated.
Results: The available space, total arch length and deciduous first intermolar width were significantly larger in non-crowded group. Significant inverse correlation were found between crowding and available space, total arch length, deciduous first intermolar width, SNA angle and lower incisor to NB angle but direct correlation was seen between crowding and anterior cranial base length.
Conclusions: This study showed that tooth size discrepancy plays only a little contributing factor and maxillary and mandibular basal bones have more influential effect on mandibular anterior crowding of the early mixed dentition. According to this study, less prognathic basal bone may increase the chance for mandibular anterior crowding.