Palatally displaced maxillary lateral incisors maybe a causative factor of mandibular deficiency

Introduction: Several factors play a role in the etiology of skeletal Class II malocclusion. Displaced maxillary incisors might have a hindering effect on mandibular growth potential.
Aim of the study: The aim of this cross-sectional study was to evaluate the influence of palatally displaced maxillary incisors on mandibular growth in a group of Egyptian patients. 
Subjects and Methods: The sample consisted of the digital lateral cephalometric radiographs of untreated 24 patients (12 females and 12 males) with age range of 15-30 years and a mean age of 22.4 years during the permanent dentition stage. The radiographs were selected from the patient database of private practice in Cairo. The sample was divided into 2 groups each consisting of 12 patients. Group A had palatally displaced maxillary lateral incisors without crossbite. Group B had palatally displaced maxillary lateral incisors with crossbite. Linear and angular cephalometric measurements (ANB & Witts appraisal) were used to assess the anteroposterior skeletal malocclusion and the position of the apical bases of the jaws in both groups. Independent samples t-test was performed to compare the results between the two groups. 
Results: Cephalometric measurements revealed statistically significant differences between groups A and B showing a mild skeletal Class II malocclusion with a retrognathic mandible in Group A (mean ANB = 4.4˚ ± 1.85), (mean Witts= 1.85 mm ± 3.22) while Group B had skeletal Class I pattern with mild skeletal Class III tendency (mean ANB= 0.8˚± 1.88), (mean Witts=-2.5mm ± 2.33).
Conclusions: Palatally displaced maxillary lateral incisors without crossbite cause restraining effect on normal mandibular growth which results in mild skeletal Class II with mandibular deficiency. However, palatally displaced maxillary lateral incisors that are in crossbite have no restraining effect on mandibular growth which results in normal to slightly excessive mandibular growth. This can be used as a tool for early prediction of mandibular growth pattern that necessitates immediate intervention.