| Prominent mandibular angles and zygoma is commonly seen in East-Asian population and does not comply with the Oriental peoples’mainstream aesthetic beauty for oval face.With the improvement of people’s living standards and the constant pursuit for beauty,the number of people who want to change the facial contour through plastic surgery is increasing.The zygoma and mandibular angel plastic surgery is a very popular cosmetic surgery in the Asian countries, and it has become one of the Maxillofacial Surgery’s hot and key research direction now.Its surgical methods continue to be improved and develop. With a lot of surgery having carried out in our country,the late effect after surgery has drawn increasing attention of the clinician.In this study,people who accepted this plastic surgery are taken as the research object and3DCT scans were included.We measured joint space of the TMJ,masticatory muscle area,zygomatic arch and mandibular width,then we made preoperative and postoperative follow-up control analysis,trying to reveal the characteristics of facial hard and soft tissue changes after mandibular angle and zygomatic arch plastic surgery, providing a theoretical basis for in-depth understanding of the osteotomy plastic surgery and getting a better clinical services, so as to improve the effect of surgery and surgical satisfaction degrees.This study is divided into the following two parts:Part I The effect of zygoma and mandibular angel plastic surgery on the masticatory musclesObjective:To observe masticatory muscles morphological changes after zygoma combined with mandibular angel osteotomy plastic surgery.Methods:We randomly selected59cases who owned prominent zygoma and mandibular angle,screening periodontal disease, temporomandibular joint pain and partial jaw.Using the same surgical techniques:bilateral zygomatic arch coarctation jaw edge of the mandibular angle resection and the mandibular body outer panel split. All of them did three-dimensional CT scan before the surgery and at10days,6months after the surgery,then finished facial three-dimensional measurement at the same time.The q test (Newman-Keuls method) were used to analysis of variance.Results:Masseter muscle and medial pterygoid muscle had the same chang trend,the cross sectional area was increased at10days after the surgery, reduced at6months after the surgery; lateral pterygoid muscle and temporal muscle had no statistical difference between the pre-and10days post-operative,however,the temporal muscle was increased while the lateral pterygoid muscle was reduced at six months after the surgery. Postoperative bilateral temporal muscle atrophy whether due to simple zygomatic arch coarctation or the complex factors caused by zygoma combined with mandibular angel osteotomy plastic surgery which still need further study.Conclusion:Because of osteotomy, muscles attached position are changed in the short term after reduction plasty of mala and zygoma and mandibular angel ostectomy,masseter muscle and medial pterygoid muscle are inevitably injuried during the operation.Within one month after surgery,patients who with semi-liquid and soft, decreased in muscle activity, so the disuse atrophy occurrenced.With the postoperative recovery,muscles have adaptive changes which reduced compared with the preoperative after their reattachment; reduction plasty of mala and zygoma can cause temporal muscle atrophy; while the operative rarely involving the lateral pterygoid muscle, the cross sectional area had no statistical difference between the pre-and10days post-operative,and the cross sectional area increase at6months post-operative may be due to a compensational enlargement. Part Ⅱ The effect of zygoma and mandibular angel plastic surgery on the TMJ condyle and Spee curveObjective:To observe the temporomandibular joint spaces changes after zygoma combined with mandibular angel osteotomy plastic surgery.Methods:We randomly selected59cases who owned prominent zygoma and mandibular angle,screening periodontal disease, temporomandibular joint pain and partial jaw.Using the same surgical techniques:bilateral zygomatic arch coarctation jaw edge of the mandibular angle resection and the mandibular body outer panel split.All of them did three-dimensional CT scan before the surgery and at10days,6months after the surgery,then measured temporomandibular joint space through0°index,60°index,120°index and180°index;The distance between both sides of the condyle;The spee curve radius.The0°index and60°index represented for pre-space,the60°index and120°index represented for upper-space,The120°index and180°index represented for aft-space.The q test (Newman-Keuls method) were used to analysis of variance.Results:0°index and60°index had the same chang trend,which slightly increased at10days after surgery,The difference between preoperative and at10days,3months after the surgery were not statistically significant (p>0.05);120°ndex and180°ndex had the same chang trend,which increased at10days after surgery.The difference between preoperative and10days after the surgery was statistically significant (p<0.05), but the difference between preoperative and three months postoperative was not statistically significant(p>0.05).pre-operation,10days and6months after surgery, none of the both sides of the condyle exterior and interior distance changes (p>0.05).Spee curve was no significant difference between preoperative and10days after surgery(p>0.05),while its radius reduced at6months after surgery and curvature increased (p<0.05).Conclusion:In the short term after the zygoma and mandibular angel plastic surgery,temporomandibular joint upper-and aft-space are changed,and the gaps reduced.There are statistical difference,but not significant.This may indicate that the temporomandibular joint has compensatory ability, short-term changes can return to normal.For muscles occlusal morphology and the edge of the mandible were both changed, so Spee curve happened adaptive changes as well.Spee curve changes suggestive of occlusal relationship has some changed,but whether with clinical significance needs further study. |
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