ABSTRACT
Objective @#To investigate the biomechanical effects of upper lip pressure on the maxilla in patients with a unilateral alveolar cleft and provide evidence for clinical diagnosis and treatment. @*Methods @#A 3D finite element maxillary model was generated based on cone beam CT (CBCT) data from an 11-year-old female patient with a unilateral alveolar cleft. Two different kinds of upper lip pressure, postsurgery pressure and normal pressure, were applied to the model. The displacement and stress of each reference node were compared and analyzed. @*Results @# By loading upper lip pressure, the maxillary alveolar crest rotated toward the defect and was displaced downward and backward. The displacement of the noncleft side was greater than that of the cleft side and it decreased gradually from the anterior to the posterior. The stress was concentrated on the anterior portion of the alveolar crest. The stress on the noncleft side was greater than that on the cleft side and it decreased gradually from the anterior to the posterior. The maximum stress was concentrated on the palate around the defect. The displacement and stress in the postsurgery group were greater than those of the normal group (P<0.05). @*Conclusion @#By loading upper lip pressure, the maxilla demonstrated asymmetry three-dimensionally. The adverse effects on the maxilla could be mitigated by reducing the upper lip pressure.
ABSTRACT
The goal of the present study was to evaluate the effects of PNAM appliance and cheiloplasty on alveolar molding. Samples consisted of 16 unilateral cleft lip and palate infants (10 males and 6 female, mean age=37.0 days after birth, average alveolar cleft gap=10.46 mm), who were treated with PNAM appliances by one orthodontist and rotation- advancement cheiloplasty by one surgeon in Seoul National University Hospital. Average duration of alveolar molding treatment was 13.10 weeks and these patients were recalled at average 8.31 weeks after cheiloplasty. These patients' models were obtained at initial visit (T0, mean age : 37.0+/-27.89 days after birth), after successful alveolar molding (T1, mean age : 119.25+/-40.18 days after birth), and after cheilopasty (T2, mean age : 190.81+/-42.78 days after birth). Seven linear and five angular variables were measured using 1 : 1 photometry and soft ware program(V-ceph. Cybermed, Seoul, Korea). Paired t-test was performed to investigate statistical significance at p < 0.05 level. 1. The posterior parts of alveolar segments were the stable structures during alveolar molding treatment period and after cheiloplasty in infants. 2. The closure of cleft gap during alveolar molding was usually due to backward bending of the whole part of the greater segment. 3. Although forward growth of the greater segment was hindered by alveolar molding, it resumed after cheiloplasty. 4. Increase of anterior inter-segment angle after cheiloplasty was due to the molding effect of the lip scar pressuren