Increased Occurrence of Dental Anomalies Associated with Infraocclusion of Deciduous Molars

Abstract

Objective: To test the null hypothesis that there is no relationship between infraocclusion and the occurrence of other dental anomalies in subjects selected for clear-cut infraocclusion of one or more deciduous molars. Materials and Methods: The experimental sample consisted of 99 orthodontic patients (43 from Boston, Mass, United States; 56 from Jerusalem, Israel) with at least one deciduous molar in infraocclusion greater than 1 mm vertical discrepancy, measured from the mesial marginal ridge of the first permanent molar. Panoramic radiographs and dental casts were used to determine the presence of other dental anomalies, including agenesis of permanent teeth, microdontia of maxillary lateral incisors, palatally displaced canines (PDC), and distal angulation of the mandibular second premolars (MnP2-DA). Comparative prevalence reference values were utilized and statistical testing was performed using the chi-square test (P , .05) and odds ratio. Results: The studied dental anomalies showed two to seven times greater prevalence in the infraocclusion samples, compared with reported prevalence in reference samples. In most cases, the infraoccluded deciduous molar exfoliated eventually and the underlying premolar erupted spontaneously. In some severe phenotypes (10%), the infraoccluded deciduous molar was extracted and space was regained to allow uncomplicated eruption of the associated premolar. Conclusion: Statistically significant associations were observed between the presence of infraocclusion and the occurrence of tooth agenesis, microdontia of maxillary lateral incisors, PDC, and MnP2-DA. These associations support a hypothesis favoring shared causal genetic factors. Clinically, infraocclusion may be considered an early marker for the development of later appearing dental anomalies, such as tooth agenesis and PDC. (Angle Orthod. 2010;80:440-445.)

Prevalence of infraocclusion of primary molars determined using a new 2D image analysis methodology

“…10,[19][20][21] The narrow age range of 8 to 11 years old, with all subjects being in the late mixed dentition phase, was selected for the samples to minimize variation in prevalence of infraocclusion that could arise due to differences in age. A discrepancy in the prevalence of infraocclusion has been reported among different age groups confirming that infraocclusion prevalence is age specific.…”

Dental anomaly pattern (DAP): Agenesis of mandibular second premolar, distal angulation of its antimere and delayed tooth formation

“…S. Peck,17 ,18 S. Peck and colleagues, 7,8,11,19 Baccetti,10,12 Baccetti and colleagues, 16 Garib and colleagues, 4 Shalish and colleagues, 5,15,20 and L. Peck and colleagues 13 are prominent among those who have contributed recently to an increased awareness of fundamental relationships among dental abnormalities.…”

“…3 Abnormal conditions such as tooth agenesis, microform teeth, delayed tooth development, palatally displaced canines, infraocclusion of deciduous molars, and MnP2 distal angulation have been found to occur together much more frequently than would be expected by chance alone. [4][5][6][7][8][9][10][11][12][13][14][15][16] Combinations of these occurrences were named dental anomaly patterns (DAPs) by Peck, 17 and they are found in nearly 25% of orthodontic patients.…”

Management of mandibular second premolar agenesis

“…The teeth most often involved are the deciduous mandibular 2 nd molars, the mandible being more often affected than the maxilla 30 .…”