| Objective1.Introduce the commonly used maxillary anterior segmental osteotomy on maxillary protrusion and modified surgical method and observe the postoperative efficacy.2.Reconstruct the three-dimensional image of bone tissue and soft tissue by using CMF software with CBCT data in patients with maxillary protrusion.Select the measurement items to evaluate the morphology change and differences of the nasal after two maxillary anterior segmental surgery.3.The CBCT data of patients were imported into CMF software for three-dimensional reconstruction,and the measurement system was established.Patient’s lateral cephalometric radiograph and frontal photos were used for measurement simultaneously.Using combination of 2D and 3D methods to evaluate the difference of lip changes between two maxillary anterior segmental osteotomy methods.Calculate the retreat amount ratio of upper incisor to upper lip.Methods1.30 patients with maxillary and bimaxillary protrusion was chosen.The patients were treated with 4 first premolar extractions followed by Cupar maxillary anterior segmental osteotomy or modified surgical method according to the distance from tooth apical to nose bottom and the thickness of alveolar bone.20 patients treated with Cupar method.10 patients underwent modified maxillary anterior segmental osteotomy which used small incision to retain anterior nasal spine and renulum labii superioris.Among 30 patients,20 patients simultaneously underwent mandibular anterior segmental and 5 patients took chin osteotomy surgery.Two cases took maxillary median osteotomy to adjust the shape of dental arch.Ten patients took orthodontic treatment before surgery and all patients took orthodontic treatment two month later after surgery.Observe the surgical effect one year after surgery.2.30 cases of maxillary and bimaxillary protrusion patients were divided into two groups,one took Cupar maxillary anterior segmental osteotomy,and the other group took modified surgical method.The CBCT data of patients were imported to CMF software to reconstruct the three-dimensional model of bone tissue and soft tissue.The measurement items were selected in bone tissue and nasal soft tissue to observe the changes after surgery.3.Select incisor and lip soft tissue measurement items in three-dimensional model of the two groups.Use lateral cephalometric radiographs and frontal photos for the lip measurements that difficult to find in 3D model.Observe the difference between the two groups in the lip area and calculate the retreat amount ratio of upper incisor to upper lip.Results1.All wounds of 30 patients healed well without infection,tooth injury and bone necrosis.There is no deformity recurrence one year after surgery.All patients had normal occlusion,normal dental arch and maxillary curve.And there is good relationship between the lips and teeth,and facial appearance is improved.2.The maxillary nasolabial angle was enlarged in both group.The inclination of the columella decreased,the height of the nose,the depth of the nose,and the base width of the alar were increased after traditional Cupar maxillary anterior osteotomy which showed statistically significant.Other measurement items showed no significant difference.In addition to maxillary nasolabial angle was enlarged and the vertical tip position decreased in modified group,the other measurement items showed no statistically significant.3.In the lip measurement items,the change of the horizontal position of the lip and the position of the neck of upper incisor tooth(UJ)had a significant positive correlation.In traditional group R = 0.768 and in modified group R = 0.771.SNA decreased and the nasolabial angle increased in both groups(P <0.05).UJ-CO and UI-CO decreased obviously(P<0.05).Upper lip(UL-CO)was significantly retreated(P <0.05),showed statistically significant.UG-CO、UL-E and Mr-Ml showed no statistically significant in both groups.UL-A increased,Stoms-Stomi and UI-Stoms decreased showed statistically significant in both groups.UL-Sn showed statistically significant increase in the modified procedure group.The retreat ratios of the point Pro of incisor and the upper lip were 1.19: 1 and 0.81: 1 in traditional group and modified group.In frontal view,it was observed that the midline lip tissue exposure become more significantly smaller although the limited change amount,the upper lip line tends to be M-type.Conclusions1.These two surgical procedures have obvious effects on maxillary protrusion deformity without obvious postoperative complications.The patients’ facial appearances are obviously improved.2.The modified maxillary anterior osteotomy had limited effect on the nasal soft tissue.The nasal height,nose depth,and the base width of nose alar were increased after traditional Cupar maxillary anterior osteotomy which had a greater impact on nose.3.The lip height increase in modified group compared to traditional group.The change of the horizontal position of the lip and the position of the neck of upper incisor tooth(UJ)had a significant positive correlation.The retreat ratios of the point Pro of incisor and the upper lip were 1.19: 1 and 0.81: 1 in traditional group and modified group.In frontal view,it was observed that the midline lip tissue exposure become more significantly smaller although the limited change amount,the upper lip line tends to be M-type which makes the lip aesthetics better. |
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