Condylar and disc positions after intraoral vertical ramus osteotomy with and without a Le Fort I osteotomy

The purpose of this study was to examine the changes in temporomandibular joint (TMJ) morphology and clinical symptoms after intraoral vertical ramus osteotomy (IVRO) with and without a Le Fort I osteotomy. Of 50 Japanese patients with mandibular prognathism with mandibular and bimaxillary asymmetry, 25 underwent IVRO and 25 underwent IVRO in combination with a Le Fort I osteotomy. The TMJ symptoms and joint morphology, including disc tissue, were assessed preoperatively and postoperatively by magnetic resonance imaging and axial cephalogram. Improvement was seen in just 50% of joints with anterior disc displacement (ADD) that received IVRO and 52% of those that received IVRO with Le Fort I osteotomy. Fewer or no TMJ symptoms were reported postoperatively in 97% of the joints that received IVRO and 90% that received IVRO with Le Fort I osteotomy. Postoperatively, there were significant condylar position changes and horizontal changes in the condylar long axis on both sides in the two groups. There were no significant differences between improved ADD and unimproved ADD in condylar position change and the angle of the condylar long axis, although distinctive postoperative condylar sag was seen. These results suggest that IVRO with or without Le Fort I osteotomy can improve ADD and TMJ symptoms along with condylar position and angle, but it is difficult to predict the amount of improvement in ADD.     

Maxillary stability following Le Fort I osteotomy in combination with sagittal split ramus osteotomy and intraoral vertical ramus osteotomy: a comparative study between titanium miniplate and poly-L-lactic acid plate.

PURPOSE: The purpose of this study was to compare changes in maxillary stability after Le Fort I osteotomy with titanium miniplate and poly-L-lactic acid (PLLA) plate (Fixsorb-MX; Takiron Co, Osaka, Japan). PATIENTS AND METHODS: The subjects were composed of 47 Japanese patients with diagnosed jaw deformity: 24 underwent Le Fort I osteotomy and sagittal split ramus osteotomy (SSRO); and 23 underwent Le Fort I osteotomy intraoral vertical ramus osteotomy without internal fixation. Each group was divided into titanium plate and PLLA plate groups. Time course changes between plate groups were compared using lateral and posteroanterior cephalography. RESULTS: Significant differences were identified between titanium plate and PLLA plate groups in A point after Le Fort I osteotomy and SSRO (P < .05). Significant differences existed between titanium plate and PLLA plate groups in vertical component of posterior nasal spine after Le Fort I osteotomy in both combinations with SSRO and intraoral vertical ramus osteotomy (P < .05). However, no significant differences were identified in measurements on posteroanterior cephalography. CONCLUSION: These results suggest a slight tendency for vertical impaction after Le Fort I osteotomy both in combination with SSRO and intraoral vertical ramus osteotomy with PLLA plates, although differences in time course changes were not clinically apparent, and normal occlusion was established in all patients.     

Postoperative stability of bimaxillary surgery in Class III patients with mandibular protrusion and mandibular deviation: a frontal cephalometric study

The aims of this study into bimaxillary surgery were to investigate and compare the postoperative stability of deviated side (lengthened side) and non-deviated side (shortened side), the effect of the type of surgery performed in the mandible, and the changes in signs and symptoms of temporomandibular joint (TMJ) disorders before and after surgery. The sample consisted of 31 Class III patients in whom imbalance between the maxilla and the mandible were corrected by Le Fort I osteotomy combined with bilateral intraoral vertical ramus osteotomy (BIVRO group, n=9), bilateral sagittal split ramus osteotomy (BSSRO group, n=10), or IVRO and SSRO (IVRO+SSRO group, n=12). IVRO+SSRO and BIVRO are more effective in improving TMJ signs and symptoms. There was no significant post-surgical difference between deviated and non-deviated sides in any group. BIVRO and BSSRO showed excellent post-surgical stability on both sides; less was found in the IVRO+SSRO group. The IVRO+SSRO group showed greater transverse displacement in menton point than the BIVRO group. In conclusion, after bimaxillary surgery and in asymmetric patients there were no differences between deviated and non-deviated sides, BIVRO and BSSRO appear to be more stable than IVRO+SSRO.     

Changes in occlusal force after mandibular ramus osteotomy with and without Le Fort I osteotomy

The purpose of this study was to evaluate the differences in bite force changes and occlusal contacts after sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) with and without Le Fort I osteotomy. Sixty female patients with diagnosed mandibular prognathism with or without asymmetry were divided into four groups (SSRO, IVRO, SSRO with Le Fort I osteotomy and IVRO with Le Fort I osteotomy). Bite force and occlusal contacts were measured preoperatively and at 1, 3, 6 and 12 months after surgery with pressure-sensitive sheets. The differences among surgical procedures were examined statistically. Maximum bite force and occlusal contacts returned to preoperative levels after between 3 and 6 months. Regarding time-dependent changes in bite force and occlusal contact area, there were no significant differences among the groups. In conclusion, this study suggests that the combination of IVRO or SSRO and Le Fort I osteotomy does not affect postoperative time-dependent changes.     

Assessment of lateral pterygoid muscle and temporomandibular joint disc after Le Fort I osteotomy with and without intentional pterygoid plate fracture and sagittal split ramus osteotomy in class II and class III patients

The aim of the study was to examine lateral pterygoid muscle (LPM) and temporomandibular joint (TMJ) disc before and after Le Fort I osteotomy with and without intentional pterygoid plate fracture and sagittal split ramus osteotomy (SSRO) in class II and class III patients.Le Fort I osteotomy and SSRO were performed in class II and class III patients. LPM measurements using oblique sagittal computed tomography (CT) images and TMJ disc position using magnetic resonance imaging (MRI) were examined. Statistical comparisons were performed for the LPM and TMJ between class II and class III patients and between those with and without intentional pterygoid plate fracture in Le Fort I osteotomy.The subjects comprised 60 female patients (120 sides), with 30 diagnosed as class II and 30 as class III. Preoperatively, the width of the condylar attachment, width at eminence, length of the LPM, angle of the LPM, and square of the LPM were significantly smaller in the class II group than in the class III group (p < 0.05). After 1 year, the width of the condylar attachment, width at eminence, and angle of the LPM remained significantly smaller in the class II group than in the class III group (p < 0.0001). TMJ disc position was significantly related to the width of the condylar attachment of the LPM, both pre- and postoperatively (p < 0.0001). However, postoperative disc position did not change in all patients. Next, the class II patients (60 sides) were divided into two groups who underwent Le Fort I osteotomy with or without intentional pterygoid plate fracture. Changes in all measurements of the LPM showed no significant differences between these two groups.Our study suggested that TMJ disc position classification could be associated with the width of condylar attachment of the LPM before and after surgery, while the surgical procedure, including Le Fort I osteotomy with intentional pterygoid plate fracture, might not affect postoperative LMP or disc position in class II patients.     

Transitional joint effusion in the mandibular prognathic surgery patient: intraoral vertical ramus osteotomy versus sagittal split ramus osteotomy.

PURPOSE: The purpose of this study was to examine the cause of joint effusion (JE) appearing postoperatively in the temporomandibular joint (TMJ) of patients with mandibular prognathism on T2-weighted magnetic resonance (MR) images. PATIENTS AND METHODS: MR imaging was performed before and after surgery in 30 TMJs of 15 subjects with mandibular prognathism who underwent intraoral vertical ramus osteotomy (IVRO) and in 20 TMJs of 10 subjects with mandibular prognathism who underwent sagittal split ramus osteotomy (SSRO). The preoperative MR imaging was performed 1 month before surgery, and postoperative MR imaging was performed during maxillomandibular fixation. RESULTS: Preoperatively, none of SSRO and IVRO groups had JE. Postoperatively, 12 TMJs (40%) of the IVRO group and only 1 TMJ (5%) of the SSRO group had JE. As for the TMJs in the IVRO group, on MR imaging, the degree of downward movement of the condyle after surgery was larger in TMJs with JE (3.8 +/- 2.3 mm) than in TMJs without JE (1.8 +/- 1.6 mm). JE diminished within about 4 months after removal of the maxillomandibular fixation. CONCLUSION: JE appearing postoperatively in the TMJ of patients with mandibular prognathism might be relation to the degree of downward movement of the condyle.     

Postoperative mandibular stability after orthognathic surgery in patients with mandibular protrusion and mandibular deviation

Skeletal stability and temporomandibular joint (TMJ) signs and symptoms were analyzed in 23 patients in whom mandibular protrusion and mandibular deviation had been corrected using bilateral sagittal split ramus osteotomy (BSSRO group, n = 10) and unilateral SSRO and intraoral vertical ramus osteotomy (USSRO+IVRO group, n = 13). Miniplate fixation was used in SSRO but no fixation was used in IVRO. The ratio of condylar bony change was 30.4% (7/23) and all condylar bony changes were seen on the deviated side. All preoperative signs and symptoms of TMJ disorders (4/13 patients in the USSRO+IVRO group and 2/10 patients in the BSSRO group) disappeared after surgery. Comparing the USSRO+IVRO group and the BSSRO group, in patients without condylar bony change, the mandible in both groups was stable anteriorly and horizontally after surgery, even though there was a larger horizontal mandibular movement in the USSRO+IVRO group during surgery. Comparing patients with condylar bony change versus no condylar bony change in the USSRO+IVRO group, postoperative horizontal mandibular displacement was significantly larger in the condylar bony change group than in the no condylar bony change group. These results support the idea that USSRO+IVRO can be useful in correcting mandibular deviation as well as improving signs and symptoms of TMJ disorders. However, it also seems important to be aware of the possibility of horizontal mandibular relapse in patients with condylar bony change.     

The assessment of blood loss in orthognathic surgery for prognathia.

PURPOSE: It is difficult to predict the need for blood transfusion during orthognathic surgery. The purpose of this study was to evaluate differences between patients who underwent different orthognathic procedures, and to assess the need for transfusion in orthognathic surgery. SUBJECTS AND METHODS: We examined 62 prognathic patients who underwent orthognathic surgery in our hospital. The subjects were divided into 4 groups according to procedure. Pre- and postoperative values of blood parameters were evaluated statistically. RESULTS: A greater amount of blood was lost in the double-jaw surgeries than in the single-jaw surgeries. There was a significant difference between sagittal split ramus osteotomy (SSRO) combined with Le Fort I osteotomy and intraoral vertical ramus osteotomy (IVRO) ( P < .05). However, none of the patients required transfusion intraoperatively. In all groups except the IVRO group, there were significant differences in red blood cell count, hemoglobin, and hematocrit between preoperative values and 1 week postoperative values ( P < .05). Although the values of red blood cell, hemoglobin, and hematocrit tended to decrease until 2 weeks postoperative, no complications occurred. Simple regression analysis showed significant positive correlation between duration of operation and blood loss ( P < .05). CONCLUSION: The present results indicate that there is little risk of marked bleeding in routine procedures, and that IVRO causes minimal bleeding. Transfusion was not necessary in IVRO or SSRO with or without Le Fort I osteotomy.     

The effects of changing position and angle of the proximal segment after intraoral vertical ramus osteotomy

The authors evaluated changes in position and angle of the proximal segment, including the condyle, after intraoral vertical ramus osteotomy (IVRO) with and without a Le Fort I osteotomy to verify whether displacement of the proximal segment could induce postoperative complications. Changes in condylar angle, ramus angle, and displacement of proximal segment were measured pre- and postoperatively. The position of the temporomandibular joint (TMJ) disc was examined pre- and postoperatively. Trigeminal nerve hypoesthesia in the lower lip was assessed bilaterally. The postoperative horizontal condylar angle was significantly smaller than the preoperative one on the deviated and non-deviated sides (P<0.0001). The postoperative coronal condylar angle was significantly larger than the preoperative one on the deviated side (P=0.0483). The postoperative sagittal ramus angle was larger than the preoperative one on the deviated (P<0.0001) and non-deviated (P=0.00005) side. Most joints with an anteriorly-displaced disc with and without reduction improved on the non-deviated side; 5 of 16 joints improved on the deviated side. Results suggest the position and angle of the proximal segment, including the condyle, could change after IVRO. This could be associated with symptomatic improvement in TMJ, and extreme medial displacement of the proximal segment could delay recovery from lower lip hypoesthesia.     

Stability of the Le Fort I osteotomy with anterior internal fixation alone: a case series.

PURPOSE: The purpose of this case series was to evaluate the late postsurgical stability of the Le Fort I osteotomy with anterior internal fixation alone and no posterior zygomaticomaxillary buttress internal fixation. PATIENTS AND METHODS: Sixty patients with maxillary vertical hyperplasia and mandibular retrognathia underwent a 1-piece Le Fort I osteotomy of the maxilla with superior repositioning and advancement or setback. A bilateral sagittal split ramus osteotomy for mandibular advancement was also performed in 22 patients. Stabilization of each maxillary osteotomy was achieved using transosseous stainless steel wires and/or 3-hole titanium miniplates in the piriform aperture region bilaterally, with no zygomaticomaxillary buttress internal fixation. (Twelve of the 60 identified patients were available for a late postoperative radiographic evaluation.) Lateral cephalometric radiographs were taken preoperatively (T1), early postoperatively (T2), and late postoperatively (T3) to analyze skeletal movement. RESULTS: These 12 patients (5 male, 7 female) had a mean age of 24.5 years at surgery. Mean time from surgery to T2 was 41.2 days; mean time from surgery to T3 was 14.8 months. One patient received anterior wire osteosynthesis fixation, while 11 patients received both anterior titanium miniplate internal skeletal fixation and anterior wire osteosynthesis fixation. Six patients underwent Le Fort I osteotomy with genioplasty, 1 patient underwent Le Fort I osteotomy with bilateral sagittal split ramus osteotomy, and 5 patients underwent Le Fort I osteotomy with bilateral sagittal split ramus osteotomy and genioplasty. These 12 patients all underwent maxillary superior repositioning with either advancement (11 patients) or setback (1 patient). Statistically significant surgical (T2-T1) changes were found in all variables measured. In late postsurgical measurements (T3-T2), all landmarks in the horizontal and vertical plane showed statistically significant skeletal stability. CONCLUSION: This case series suggests that anterior internal fixation alone in cases of 1-piece Le Fort I maxillary superior repositioning with advancement has good late postoperative skeletal stability.     

A new osteotomy for the correction of mandibular prognathism: techniques and rationale of the intraoral vertico-sagittal ramus osteotomy.

The sagittal split ramus osteotomy (SSRO) and the intraoral vertical ramus osteotomy (IVRO) are long established methods for correcting mandibular prognathism, each having its own advantages. However, both procedures have the same disadvantage: the potential for postoperative condylar displacement. The displacement of the condyle is mainly due to the fact that the osteotomy plane is not parallel to the original sagittal plane in which the mandible is repositioned. The author has developed a new ramus osteotomy since 1985 in which the osteotomy plane is theoretically parallel to the original sagittal plane and thereby attempting to decrease the incidence of condylar displacement. This osteotomy was designed additionally to decrease neurosensory disturbances and has the advantages of both methods, and therefore has been named 'intraoral vertico-sagittal ramus osteotomy (IVSRO)'. Initial experience with the 24 prognathic patients operated on by means of the IVSRO indicated excellent clinical results. It has been noted clinically that the IVSRO is very effective in reducing postoperative iatrogenic TMJ symptoms and in treating preoperative TMJ symptoms. It has the additional effect of reducing neurosensory disturbances. This osteotomy seems to be more applicable in mandibular prognathism with excessive flaring of the ramus, particularly that associated with TMJ dysfunction, because the IVSRO has a 'condylotomy effect' and its splitting plane diverges less from the original sagittal plane than that of the SSRO and the IVRO.     

Change in condylar long axis and skeletal stability following sagittal split ramus osteotomy and intraoral vertical ramus osteotomy for mandibular prognathia.

PURPOSE: The purpose of this study was to compare postsurgical time course changes in condylar long axis and skeletal stability between sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO). PATIENTS AND METHODS: Of 40 Japanese patients with a diagnosed jaw deformity, 20 underwent IVRO without internal fixation and 20 underwent SSRO with rigid internal fixation. The time course change in condylar long axis and skeletal stability were assessed with axial, frontal, and lateral cephalograms. RESULTS: A significant difference in the rotation direction of condylar long axis was seen in horizontal axial cephalogram images (P <.01). In Pog-N perpendicular to SN, the IVRO group showed gradual decrease, although SSRO group showed gradual increase in lateral cephalogram (P <.05). CONCLUSION: The present results suggest a significant difference between SSRO and IVRO in time course changes in proximal segment including condyle and distal segment.     

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.     

Recovery of mandibular mobility following orthognathic surgery

The aim of this prospective study was to define the patterns of recovery of mandibular mobility following three commonly performed orthognathic surgical procedures. Twenty-two consecutive patients undergoing either isolated Le Fort I osteotomy (LE FORT; n = 7), sagittal split ramus osteotomies (SSRO; n = 7), or intraoral vertical ramus osteotomies (IVRO; n = 9) were studied. LE FORT and SSRO patients had no mandibular immobilization, whereas IVRO patients were immobilized by dental fixation for 3 weeks. Mandibular mobility was assessed by measurement of maximal mandibular opening (MMO) and lateral and protrusive excursions. No significant difference in MMO was observed between groups prior to surgery (LE FORT, 47.0 mm; SSRO, 50.7 mm; IVRO, 54.5 mm). A significant reduction in MMO occurred immediately after surgery in the LE FORT and SSRO groups and at release of fixation in the IVRO group. Each group returned to presurgical levels of mandibular mobility at a different rate following surgery. LE FORT patients recovered quickly, regaining 83% (mean, 38.7 mm) of MMO by 1 month and exceeded preoperative levels (mean, 49.6 mm) by 6 months. SSRO patients showed hypomobility (mean, 23.5 mm) after 1 month, with significant improvement in MMO (mean, 38.0 mm) at 2 months, and nearly complete recovery (96.2%; mean, 48.8 mm) at 6 months. IVRO patients recovered rapidly after release of dental fixation, achieving 78% (mean, 39.8 mm) of preoperative MMO at 2 months. This study shows that significant differences in recovery patterns of mandibular mobility exist between surgical procedures. The clinician should be aware of these differences in recovery patterns in defining goals for individual patient rehabilitation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of treatment with unilateral mandibular sagittal split ramus osteotomy and maxillary osteotomy in patients with condylar osteochondroma and mandibular asymmetry: A retrospective case series

The aim of the study was to describe an approach where condylar resection with condylar neck preservation was combined with Le Fort I osteotomy and unilateral mandibular sagittal split ramus osteotomy (SSRO).Patients with a unilateral condylar osteochondroma combined with dentofacial deformity and facial asymmetry who underwent surgery between January 2020 and December 2020 were enrolled. The operation included condylar resection, Le Fort I osteotomy and contralateral mandibular sagittal split ramus osteotomy (SSRO). Simplant Pro 11.04 software was used to reconstruct and measure the preoperative and postoperative craniomaxillofacial CT images. The deviation and rotation of the mandible, change in the occlusal plane, position of the “new condyle” and facial symmetry were compared and evaluated during follow-up. Three patients were included in the present study. The patients were followed up for 9.6 months on average (range, 8–12). Immediate postoperative CT images showed that the mandible deviation and rotation and occlusion plane canting decreased significantly postoperatively; facial symmetry was improved but still compromised. During the follow-up, the mandible gradually rotated to the affected side, the position of the “new condyle” moved further inside toward the fossa, and both the mandible rotation and facial symmetry were more significantly improved.Within the limitations of the study it seems that for some patients a combination of condylectomy with condylar neck preservation and unilateral mandibular SSRO can be effective in achieving facial symmetry.     

不同正颌外科方案对骨性Ⅲ类伴前牙开(恰) 垂直向稳定性的影响

目的 比较不同正颌外科手术方案对骨性Ⅲ类错伴前牙开术后垂直向稳定性的影响.方法 收集入院接受手术的骨性Ⅲ类错伴前牙开畸形患者122例,分别采用双侧下颌升支矢状劈开(BSSRO)(50例)、下颌升支垂直骨劈开(IVRO)(30例)、BSSRO+Le FortⅠ(22例)、IVRO+Le FortⅠ(20例)作为手术方案,并且除IVRO方案外其他所有方案病例均接受钛板颌骨内坚固内固定术.术后正畸完成时及完成后6、24个月时随访接受临床检查与头影测量分析评估垂直向复发情况,观察指标包括覆、下颌平面角、颌间夹角.结果 01)BSSRO+Le FortⅠ与IVRO+Le FortⅠ组覆显著减小的比率在6、24个月都少于BSSRO与IVRO组.2)BSSRO+Le FortⅠ组与IVRO+Le FortⅠ组下颌平面角显著增加的比率在6、24个月都少于BSSRO与IVRO组.3)6个月时BSSRO+Le FortⅠ组与IVRO+Le FortⅠ组颌间夹角显著增加的比率少于BSSRO组与IVRO组,而24个月时无统计学差异.结论 双颌外科(BSSRO+Le FortⅠ与IVRO+Le FortⅠ)均比单颌外科(BSSRO与IVRO)能更加有效地减少垂直向复发的数量和幅度.     

Surgical orthodontic treatment for a patient with unilateral cleft lip and palate and temporomandibular disorder

The patient was a 12-year-old female who presented with unilateral cleft lip and palate, facial asymmetry, mandibular protrusion, resorption of condyle heads, and transverse maxillary deficiency. At the age of 13 years 10 months, maxillary expansion and autogenous bone graft were performed to improve the maxillary collapsed arch. Aged 14 years 10 months, she described symptoms of temporomandibular joint pain and dysfunction. Segmental Le Fort I osteotomy and intraoral vertical ramus osteotomy (IVRO) were performed at the age of 15 years 11 months. Segmental Le Fort I osteotomy resulted in improved sagittal and transverse discrepancy of the maxilla. After IVRO, facial symmetry, a good facial profile, and disappearance of TMD symptoms were achieved. The occlusion and esthetics were stable after 5 years of retention.     

A comparison of postoperative hypoesthesia between two types of sagittal split ramus osteotomy and intraoral vertical ramus osteotomy, using the trigeminal somatosensory-evoked potential method

The purpose of this study was to evaluate hypoesthesia of the lower lip using trigeminal somatosensory-evoked potential following 2 types of sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO). There were 30 patients with mandibular prognathism, with and without asymmetry, who were divided into three groups: the Obwegeser method (Ob) group, the Obwegeser-Dal Pont method (ODP) group and the intraoral vertical ramus osteotomy (IVRO) group. The trigeminal somatosensory-evoked potential was recorded in the region of the lower lip and evaluated preoperatively and postoperatively. The average recovery periods from lower lip hypoesthesia in the IVRO and the Ob group were significantly shorter than in the ODP group (P<0.05). In conclusion, IVRO showed the earliest recovery from hypoesthesia or an absence of hypoesthesia, and lower lip hypoesthesia was less with the Ob method than the ODP method.     

Evaluation of condylar surface CT values related to condylar height reduction after orthognathic surgery

This study was performed to evaluate the relationship between condylar height reduction and changes in condylar surface computed tomography (CT) values in jaw deformity patients following orthognathic surgery.Mandibular advancement by sagittal split ramus osteotomy (SSRO) with Le Fort I osteotomy was performed in class II patients, and mandibular setback by SSRO with Le Fort I osteotomy was performed in class III patients. The maximum CT values (pixel values) at five points on the condylar surface and the condylar height, ramus height, condylar square, ramus angle, and gonial angle in the sagittal plane were measured preoperatively and 1 year postoperatively. Disc position was classified as anterior disc displacement (ADD) or other types by using magnetic resonance imaging (MRI).Ninety-two condyles of 46 female patients were prepared for this study. Their temporomandibular joints (TMJs) were divided into two groups based on class (46 joints in class II and 46 joints in class III) and two groups based on the findings (25 joints with ADD and 67 joints with other findings). ADD with and without reduction was observed in two joints in the class III group and in 23 joints in the class II group. The distribution of ADD incidence had not changed 1 year after surgery. Condylar height decreased 1 year after surgery in both class II patients (mandibular advancement) (p < 0.0001) and class III patients (mandibular setback) (p = 0.0306). Similarly, condylar height decreased 1 year after surgery both in patients who showed ADD (p = 0.0087) and those with other types (p = 0.0023). Significant postoperative increases at all angle sites on the condylar surface were found in the class II (p < 0.05) and ADD (p < 0.05) groups.This study showed that an enhanced condylar surface CT value might be one sign of condylar height reduction related to sequential condylar resorption, in combination with ADD.     

Surgical morbidities of sagittal split ramus osteotomy versus intraoral vertical ramus osteotomy for the correction of mandibular prognathism: a randomized clinical trial

The sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) are two common orthognathic procedures for the treatment of mandibular prognathism. This randomized clinical trial compared the surgical morbidities between SSRO and IVRO for patients with mandibular prognathism over the first 2 years postoperative. Ninety-eight patients (40 male, 58 female) with a mean age of 24.4 ± 3.5 years underwent bilateral SSRO (98 sides) or IVRO (98 sides) as part or all of their orthognathic surgery. IVRO presented less short-term and long-term surgical morbidity in general. The SSRO group had a greater incidence of inferior alveolar nerve deficit at all follow-up time points (P <  0.01). There was more TMJ pain at 6 weeks (P =  0.047) and 3 months (P =  0.001) postoperative in the SSRO group. The SSRO group also presented more minor complications, which were related to titanium plate exposure and infection. There were no major complications for either technique in this study. Despite the need for intermaxillary fixation, IVRO appears to be associated with less surgical morbidity than SSRO when performed as a mandibular setback procedure to treat mandibular prognathism.