Changes in border movement of the mandible in skeletal Class III before and after orthognathic surgery

The purpose of this study was to examine the changes in border movement of the mandible before and after mandibular ramus osteotomy in patients with prognathism. The subjects were 73 patients with mandibular prognathism who underwent sagittal split ramus osteotomy (SSRO) with and without Le Fort I osteotomy. Border movement of the mandible was recorded with a mandibular movement measure system (K7) preoperatively and at 6 months postoperatively. Of the 73 patients, 21 had measurements taken at 1.5 years postoperative. Data were compared between the pre- and postoperative states, and the differences analyzed statistically. There was no significant difference between SSRO alone and SSRO with Le Fort I osteotomy in the time-course change. The values at 6 months postoperative were significantly lower than the preoperative values for maximum vertical opening (P = 0.0066), maximum antero-posterior movement from the centric occlusion (P = 0.0425), and centric occlusion to maximum opening (P = 0.0300). However, there were no significant differences between the preoperative and 1.5 years postoperative measurements. This study suggests that a postoperative temporary reduction in the border movement of the mandible could recover by 1.5 years postoperative, and the additional procedure of a Le Fort I osteotomy does not affect the recovery of mandibular motion after SSRO.     

骨支持式3D打印导板在上颌骨LeFortⅠ型截骨术中的应用

目的 探讨3D打印技术制作的截骨导板和再定位导板在上颌骨LeFortⅠ型截骨术中的应用效果。方法 选择8例因上颌发育不良行LeFortⅠ型截骨术的的患者为研究对象,所有患者均进行锥形束CT（CBCT）扫描并建立上颌骨三维模型,使用3D打印技术制作上颌骨截骨导板和再定位导板。所有手术均由同一名医生操作,术中使用截骨导板截骨和再定位导板固定上颌骨块。术后复查CBCT,测量6个标志点到3个基准平面的距离,比较术前虚拟手术与实际手术中上颌骨的位移误差,评估其用于正颌术中上颌骨截骨和再固定的准确性。结果 术后所有患者口内切口均Ⅰ期愈合,无明显并发症。位移误差均值最大为1.35 mm,是左上磨牙点到冠状平面的位移误差;标准差最大为0.85,标准误最大为0.30。位移误差均为临床所接受范围。结论 3D打印技术制作的截骨导板和再定位导板有助于安全、准确地完成上颌骨LeFortⅠ截骨术。     

Comparison of the accuracy of maxillary position between conventional model surgery and virtual surgical planning

The aim of this study was to determine whether virtual surgical planning (VSP) is an accurate method for positioning the maxilla when compared to conventional articulator model surgery (CMS), through the superimposition of computed tomography (CT) images. This retrospective study included the records of 30 adult patients submitted to bimaxillary orthognathic surgery. Two groups were created according to the treatment planning performed: CMS and VSP. The treatment planning protocol was the same for all patients. Pre- and postoperative CT images were superimposed and the linear distances between upper jaw reference points were measured. Measurements were then compared to the treatment planning, and the difference in accuracy between CMS and VSP was determined using the t-test for independent samples. The success criterion adopted was a mean linear difference of <2 mm. The mean linear difference between planned and obtained movements for CMS was 1.27 ± 1.05 mm, and for VSP was 1.20 ± 1.08 mm. With CMS, 80% of overlapping reference points had a difference of <2 mm, while for VSP this value was 83.6%. There was no statistically significant difference between the two techniques regarding accuracy (P > 0.05).     

Is the removal of osteosynthesis plates after orthognathic surgery necessary? Retrospective long-term follow-up study

The removal of titanium miniplates is a controversial topic in oral and maxillofacial surgery. This retrospective study examined the timing of and reasons for titanium plate removal after orthognathic surgery. The study included 240 orthognathic surgery patients (71 male, 169 female; age range 16–55 years, mean 25.0 ± 8.8 years) who had maxillofacial osteosynthesis plates inserted or inserted and then removed at the Division of Oral and Maxillofacial Surgery, Kagawa Prefectural Central Hospital, between April 2003 and March 2017. During the study period, a total of 717 miniplates were inserted in the 240 patients, and 71 of the patients (29.6%) had 236 plates (32.9%) removed. Ten patients (14.1%) had their plates removed within a year due to early complications. Although no patient had their plate removed due to complications at 1–5 years postoperative, a further 14 patients (19.7%) had their plates removed after more than 5 years of long-term follow-up due to plate-related complications. Complications requiring plate removal were evidently biphasic, occurring within 1 year after the operation and at ≥5 years after the operation. Therefore, after confirming postoperative bone healing, it is necessary to explain to patients the risks of plate removal and the importance of long-term follow-up.     

Comparison of Tooth- and Bone-Borne Appliances on the Stress Distributions and Displacement Patterns in the Facial Skeleton in Surgically Assisted Rapid Maxillary Expansion—A Finite Element Analysis (FEA) Study

The aim of this study was to compare the reduced stresses according to Huber’s hypothesis and the displacement pattern in the region of the facial skeleton using a tooth- or bone-borne appliance in surgically assisted rapid maxillary expansion (SARME). In the current literature, the lack of updated reports about biomechanical effects in bone-borne appliances used in SARME is noticeable. Finite element analysis (FEA) was used for this study. Six facial skeleton models were created, five with various variants of osteotomy and one without osteotomy. Two different appliances for maxillary expansion were used for each model. The three-dimensional (3D) model of the facial skeleton was created on the basis of spiral computed tomography (CT) scans of a 32-year-old patient with maxillary constriction. The finite element model was built using ANSYS 15.0 software, in which the computations were carried out. Stress distributions and displacement values along the 3D axes were found for each osteotomy variant with the expansion of the tooth- and the bone-borne devices at a level of 0.5 mm. The investigation showed that in the case of a full osteotomy of the maxilla, as described by Bell and Epker in 1976, the method of fixing the appliance for maxillary expansion had no impact on the distribution of the reduced stresses according to Huber’s hypothesis in the facial skeleton. In the case of the bone-borne appliance, the load on the teeth, which may lead to periodontal and orthodontic complications, was eliminated. In the case of a full osteotomy of the maxilla, displacements in the buccolingual direction for all the variables of the bone-borne appliance were slightly bigger than for the tooth-borne appliance.     

正颌外科术后髁突移位的病因与治疗研究进展

不同程度的髁突移位是正颌外科术后常见并发症。术后髁突移位可能是由于重新定位的颌骨固定不充分、固定期间髁突表面再吸收及髁突在颞下颌关节内缺乏被动就位等多方面因素所致。这些问题可能会使再次治疗的难度变大,患者心理负担增加,也可能会影响患者的依从性。因此,正颌外科术后髁突移位的治疗与预防是近年来学者们重点研究的方向。文章就正颌外科术后髁突移位的病因、治疗与预防方法研究进展做一综述。     

牙颌面畸形患者手术前后生活质量变化研究

目的    评估牙颌面畸形患者正颌手术前后口腔健康相关生活质量的变化,为临床方案制定和医患沟通提供参考。方法    选择2019年6—12月于中国医科大学附属口腔医院口腔颌面外科接受正颌手术的牙颌面畸形患者35例作为研究组,100名健康正常人作为对照组,以正颌手术生活质量问卷（OQLQ）对患者手术前后口腔健康相关生活质量进行评估。结果    牙颌面畸形患者的口腔功能、面部美学、牙颌面美学感知以及社会因素的术后评分均低于术前（P < 0.001）,术前评分均高于对照组（P < 0.001）;术后牙颌面美学感知和社会功能的评分高于对照组（P < 0.05）。结论    牙颌面畸形患者正颌手术术前的口腔健康相关生活质量低于正常群体,术后各维度比术前均明显改善,但术后牙颌面美学感知和社会功能方面的生活质量仍低于正常人群。     

Do changes in oral health-related quality-of-life,facial pain and temporomandibular disorders correlate after treatment of severe malocclusion?

Introduction. The aim was to evaluate the relationships of changes in facial pain, temporomandibular disorders (TMDs) and oral health-related quality-of-life (OHRQoL) in adults who underwent orthodontic or orthodontic/surgical treatment. Methods. Sixty-four patients (46 women, 18 men, range 18–64 years) with severe malocclusion and functional problems were treated in Oulu University Hospital. Of these, 44 underwent orthodontic-surgical and 20 orthodontic treatment. Data were collected with questionnaires and clinical stomatognathic examinations before and on average 3 years after treatment. The OHRQoL was measured with OHIP-14 (The Oral Health Impact Profile), the intensity of facial pain with the Visual Analogue Scale (VAS) and the severity of TMD with the Helkimo’s anamnestic (Ai) and clinical (Di) dysfunction indices. Results. A significant improvement was found in facial pain, signs and symptoms of TMD and OHRQoL after the treatment (p < 0.05). The decrease in VAS was associated with improvement in OHIP-14 severity (r = 0.296, p = 0.019). The correlations between changes in OHIP-14 severity and Ai and Di were not statistically significant. Conclusion. Treatment of severe malocclusion seemed to improve OHRQoL via decreased facial pain. Decreased facial pain was associated especially with improved OHRQoL dimensions of physical pain, physical disability and social disability.     

Interaction between posture and maxillomandibular deformity: a systematic review

Maxillomandibular deformity (MMD) and body posture appear to be correlated. However, no systematic literature review of the available evidence to support this correlation has been performed to date. The aim of this study was to conduct a systematic literature review on posture and MMD. This systematic literature review was registered in the PROSPERO database. Systematic searches of the MEDLINE, Scopus, Cochrane Library, and Web of Science databases were performed. In total, 13 clinical studies were included. Nine found a significant association between MMD and body posture or body balance: two studies showed a correlation between increased cervical lordosis and skeletal class III MMD, two studies showed an interaction between mandibular deviation and scoliosis, four studies demonstrated a significant association between lumbar column and pelvis anatomy and MMD, and one study found a correlation between displacement of the centre of mass and MMD. However, the level of evidence is low; the methods used to evaluate body posture and MMD were inconsistent. Orthognathic surgery could modify body posture. Although there seems to be an interaction between body posture and facial deformity, the number of studies is too small and the level of evidence too low to strongly support this association.     

Extraoral vertical ramus osteotomy combined with internal fixation for the treatment of mandibular deformities

Extraoral vertical ramus osteotomy (EVRO) is used in orthognathic surgery for the treatment of mandibular deformities. Originally, EVRO required postoperative intermaxillary fixation (IMF). EVRO has been developed using rigid fixation, omitting postoperative IMF. We examined retrospectively the long-term stability and postoperative complications for patients with mandibular deformities who underwent EVRO with internal rigid fixation. Patients who were treated with EVRO for a mandibular deformity in the period 2008–2017 at the Clinic of Oral and Maxillofacial Surgery, Mölndal, Sweden were included (N = 26). Overjet and overbite were calculated digitally and cephalometric analyses were performed preoperatively, and at three days, six months, and 18 months postoperatively. There was a general setback of the mandible, decreased gonial angle and reduced degree of skeletal opening. Excellent dental and vertical skeletal stabilities were seen up to 18 months postoperatively, although relapse was seen sagitally up to six months postoperatively. Since the overjet did not show any significant change over time, the sagittal skeletal changes have been attributed to dental compensation. There was no permanent damage to the facial nerve and 5.8% neurosensory damage to the inferior alveolar nerve was observed.