Orthodonticorthognathic treatment stability in skeletal class III malocclusion patients / 北京大学学报(医学版)

ABSTRACT

OBJECTIVE@#To investigate stability of skeletal hard tissues, dental hard tissues and soft tissues after orthodonticorthognathic treatment in a long term. This study reviewed longitudinal changes in orthodontic-orthognathic patients of skeletal class III malocculsion, using lateral cephalometric radiographs in 3-12 years after treatment in comparison to treatment finishing.@*METHODS@#Twenty-two patients with skeletal Class III malocclusion following orthodontic-orthognathic surgery in Peking University School and Hospital of Stomatology from January 1, 2000 to January 1, 2009 were observed. The lateral cephalometric radiographs of the following stages were collected treatment finishing (T1), 3 to 12 years after treatment (T2). Statistical analyses of cephalometrics were evaluated. Paired student t test was performed by SPSS 17.0.@*RESULTS@#Data of all the 22 patients were studied in longitudinal timeline after treatment and 3-12 years after treatment. From T1 to T2, we evaluated 11-SN (angle between the upper incisors axis and SN plane), 11-NA angle (angle between the upper incisors axis and NA plane), 11-NA mm (perpendicular distance from upper incisors to NA plane), 11-41 (angle between the upper incisors axis and lower incisors axis), 41-NB angle (angle between lower incisors and NB plane), 41-NB (perpendicular distance from lower incisors to NB plane), 41-MP angle (angle between lower incisors and GoGn plane), and IMPA [angle between lower incisor and mandibular plane (tangent line to submandibular border)]. Most hard tissues of the teeth remained stable but upper anterior teeth angulations decreased, indicating by significantly reducing 11-SN (T1 110.98°±6.77°; T2 109.21°±5.80°; P=0.005); reducing 11-NA (T1 28.31°±6.80°; T2 26.49°±6.18°; P=0.002); increasing 11-41 (T1 123.51°±8.14°; T2 125.7°±10.01°; P=0.035). From T1 to T2, we also evaluated SNA (angle of sella-nasion-A-point), SNB (angle of sella-nasion-B-point), ANB (angle of A-point-nasion-B-point), GoGn-SN (angle between GoGn and SN plane), GoGn-FH (angle between GoGn and Frankfort plane), Y axis (angel between Sella-Gn and Frankfort plane), N-ANS (distance from nasion point to ANS point), ANS-Me (distance from ANS point to Menton point), N-Me (distance from nasion point to Menton point), ANS-Me/N-Me% (proportion of ANS-Me to N-Me), and FMA (angle between Frankfort and mandibular plane), Wits appraisal (horizontal distance between points A and B on functional occlusal plane). Skeletal hard tissues also remained relatively stable, only N-Me value changed significantly with a decreasing facial height (T1 124.98°±11.98°; T2 122.4°±11.05°; P=0.024). From T1 to T2, we finally evaluated FH-NsPg angle (angle between NsPg and Frankfort plane), H angle (angel between H line and NB), FH-A'UL angle (angle between A'UL and Frankfort plane), FH-B'LL angle (angle between B'LL and Frankfort plane), UL-LL (angle between UL and LL), UL-EP (distance between UL and E line), LL-EP (distance between LL and E line), Sn-H (perpendicular distance between Sn point and H line), Nls-H (distance of nose-lip-sulcus to H line), Li-H (lower lip to H line), Si-H (lower lip sulcus to H line), and NLA (nasolabial angle, angle of Cm-Sn-UL-point). Soft tissues changes were observed in decreasing UL-EP [T1 (-2.78±2.20) mm; (-3.29±2.44) mm; P=0.02] and H angle (T1 8.27°±3.71°; 7.32°±3.83°; P=0.006). Other soft tissues remained relatively stable by retruding upper lip position and chin changes with no statistical significance.@*CONCLUSION@#Orthodontic-orthognathic treatment can improve esthetics and occlusal function in patients of skeletal class III malocclusion with a stable long-term outcome.