Mandibular Stability Research Articles

Are Cellular Bone Matrix Allografts a Viable Option for Mandibular Tissue Engineering and Reconstruction?

BackgroundTraditional mandibular reconstruction has relied on the use of vascularized and non-vascularized autografts. The use of allografts and tissue engineering modalities has risen as an alternative. PurposeThe purpose of this study was to determine the success of a cellular bone matrix (CBM) allograft composed of lineage committed bone forming cells for mandibular tissue engineering and reconstruction. Study design, setting, sampleA retrospective cohort study was implemented using data from subjects treated with a CBM at the University of Louisville from 2019 to 2023. Subjects were excluded if they were not treated with a CBM, data were not complete, or postoperative follow-up time was less than 3 months. Predictor variablesThe predictor variables were composed of heterogenous variables grouped into the following categories: demographics (age, sex), medical history (history of penicillin (PCN) allergy, history of diabetes mellitus (DM) and tobacco use), etiology (benign tumor, ballistic trauma, non-ballistic trauma, odontogenic cyst, osteomyelitis/MRONJ), mandibular resection length (cm) and type (marginal, segmental), delayed vs immediate reconstruction, and whether an autograft (proximal tibia, TBG) with platelet rich fibrin (PRF) was used in combination with the CBM. Main outcome variableThe primary outcome variable was graft success (yes or no). Success was defined as bony union and defect fill (demonstrated on panoramic radiograph) and mandibular stability (based on postoperative clinical examination at 3 months). CovariatesNot applicable. AnalysesDescriptive statistics were calculated for each variable. To measure the associations between the risk factors and graft success, Fisher’s exact test for categorical variables and the Wilcoxon rank sum test for numeric data were used. A p-value of <0.05 was considered significant. ResultsThe sample included 38 subjects. The median age of all subjects was 46 (IQR 32.6) years. Overall, 28 (73.7%) cases were successful. Subjects with a reported PCN allergy or a history of DM had significantly lower success (2, 7.1% with PCN allergy or DM) compared to those who did not (p = 0.008, PCN allergy; p = 0.03, DM). Conclusions and RelevanceThis is the largest case series of CBM based mandibular reconstruction relative to the available maxillofacial surgery literature. The clinician should consider confirmation of penicillin allergy so penicillin-type antibiotics can be used. CBMs may be an alternative to autografts.

Cephalometric evaluation of skeletal stability and pharyngeal airway changes after mandibular setback surgery: Bioabsorbable versus titanium plate and screw fixation.

This study compared sequential changes in skeletal stability and the pharyngeal airway following mandibular setback surgery involving fixation with either a titanium or a bioabsorbable plate and screws. Twenty-eight patients with mandibular prognathism undergoing bilateral sagittal split osteotomy by titanium or bioabsorbable fixation were randomly selected in this study. Lateral cephalometric analysis was conducted preoperatively and at 1 week, 3-6 months, and 1 year postoperatively. Mandibular stability was assessed by examining horizontal (BX), vertical (BY), and angular measurements including the sella-nasion to point B angle and the mandibular plane angle (MPA). Pharyngeal airway changes were evaluated by analyzing the nasopharynx, uvula-pharynx, tongue-pharynx, and epiglottis-pharynx (EOP) distances. Mandibular and pharyngeal airway changes were examined sequentially. To evaluate postoperative changes within groups, the Wilcoxon signed-rank test was employed, while the Mann-Whitney U test was used for between-group comparisons. Immediate postoperative changes in the airway were correlated to surgical movements using the Spearman rank test. Significant changes in the MPA were observed in both the titanium and bioabsorbable groups at 3-6 months post-surgery, with significance persisting in the bioabsorbable group at 1 year postoperatively (2.29°±2.28°; P<0.05). The bioabsorbable group also exhibited significant EOP changes (-1.21±1.54 mm; P<0.05) at 3-6 months, which gradually returned to non-significant levels by 1 year postoperatively. Osteofixation using bioabsorbable plates and screws is comparable to that achieved with titanium in long-term skeletal stability and maintaining pharyngeal airway dimensions. However, a tendency for relapse exists, especially regarding the MPA.

Surgical occlusion setup and skeletal stability of correcting cleft-associated class III deformity using surgery-first bimaxillary surgery.

This study aimed to assess the three-dimensional (3D) quantitative characteristics of the surgical occlusion setup in surgery-first cleft orthognathic surgery, and to evaluate its influence on post-surgical skeletal stability. This prospective study was comprised of 35 patients with unilateral cleft lip and palate and class III deformity who consecutively underwent two-jaw surgery with surgery-first approach. Digitized dental models were analyzed to quantify the 3D characteristics of the final surgical occlusion setup. Cone-beam computed tomography was used to measure the 3D surgical skeletal movement and post-surgical skeletal stability. The correlation between skeletal stability and surgical occlusal contact or surgical skeletal movement was also evaluated. The surgical occlusion setup had a large incisor overjet and positive overbite, and buccal cross bite and open bite on second molars. Occlusal contact on three segments was present in 51.4% of the patients, and the average number for tooth contact was 4.3 teeth. No correlation was found between maxillary or mandibular stability and surgical occlusal contact. However, a significant correlation was found between maxillary and mandibular stability and the surgical skeletal movement. The surgical occlusion for correction of cleft-associated class III deformity using the surgery-first approach was characterized with large overjet and positive overbite, and posterior cross bite and open bite. On average, there was occlusal contact on four to five teeth; half of surgical occlusion setups had contact on three segments. The post-surgical skeletal stability was not related to the surgical occlusal contact but to the surgical skeletal movement.

The effect of different hybrid rigid internal fixation techniques on the postoperative stability following a mandibular advancement using a bilateral sagittal split ramus osteotomy: A retrospective three-dimensional comparative study

ObjectiveTo three-dimensionally evaluate post-operative mandibular stability following bilateral sagittal split ramus osteotomies between hybrid and non-hybrid rigid internal fixation techniques. Materials and MethodSeventy adults with skeletal class II deformity who underwent bilateral split sagittal osteotomy with mandibular advancement were included. Patients were divided into four groups based on their fixation techniques: hybrid technique (HT) groups I, II, and IV received a 4-hole 2 mm miniplate with either a bicortical screw (BS), additional 2 mm 4-hole miniplate, or two-hole miniplate, while non-HT group III received a 4-hole 2 mm miniplate with four mini-screws (MS). Measurements were taken pre-operatively (T0), immediately postoperatively (T1), and ≥1 year after surgery (T2) using 3D Slicer software. ResultsAge, sex, and follow-up period did not correlate significantly with postoperative relapse or stability. Significant differences were observed in the advancement on the right side between groups II, III, and IV and on the left side between groups I, III, and IV. However, the type of surgical intervention showed no significant effect on postoperative relapse and stability. All groups of fixations showed satisfactory stability with irrelevant relapse (< 2 mm or 2°). ConclusionThe study demonstrated satisfactory and comparable stability among different fixation groups on patients undergoing mandibular advancement following bilateral split sagittal osteotomy. The results highlighted the importance of considering the degree of advancement when planning orthognathic surgery and managing postoperative outcomes.

Stability and failure rate during 3 years of fixed retention: A follow-up of an randomized clinical trial on adolescents with four different lingual retainers.

To evaluate stability outcomes and failure rates associated with four types of lingual retainers: (1) dead-soft wire, (2) multistrand stainless steel (SS) wire, (3) CAD/CAM nitinol, and (4) connected bonding pads (CBPs) after 3 years of retention. This study enrolled 96 patients (66 females, 30 males) with a median age of 19 years with four types of lingual retainers: (1) 0.016 × 0.022-inch dead-soft wire, (2) 0.0215-inch five-strand SS wire, (3) 0.014 × 0.014-inch CAD/CAM nitinol wire, and (4) CBPs. The irregularity index, intercanine distances, and arch lengths were obtained and used to evaluate mandibular stability. Failure rates were also assessed during this study. Data were statistically analysed. Irregularity increased, whereas intercanine width and arch length decreased after 3 years of retention. The greatest irregularity was associated with the CBPs and the least with the CAD/CAM retainers. Changes in stability measurements were significantly higher in the dead-soft wire and CBPs than those in the CAD/CAM nitinol and multistrand SS wires. Parallel to these changes, the frequency of failure yielded similar results with the same significance between the groups. The failure rate of CBPs, in contrast to the CAD/CAM nitinol and multistrand SS wires, was significantly higher in the right quadrant (P < .05). After taking the 3-year results into consideration, CAD/CAM nitinol and multistrand SS wires were found to be more successful than the others in maintaining mandibular stability. The most failures were observed with CBPs after 3 years of retention.

A retrospective three-dimensional study of the mandibular growth during preoperative orthodontics in late adolescent patients with skeletal Class III malocclusion

IntroductionThe mandible's ongoing development presents a contraindication for combined orthodontic–orthognathic treatment. The aim of this study was to evaluate the mandibular stability before and after preoperative orthodontic treatment in late adolescent patients with skeletal Class III malocclusion and to investigate the most appropriate time to start preoperative orthodontic treatment. Material and methodsThe study population consisted of 58 adolescents, aged between 15 and 21 years, with skeletal Class III malocclusion; the adolescents underwent CT scans at the beginning (T1) and the end (T2) of preoperative orthodontic treatment. The CT data were analyzed using ITK-SNAP and 3D Slicer software, and the effects of age and gender on mandibular development were investigated. ResultsIn these 58 patients, there were no significant local bone alterations in the condyle and anterior chin point between T1 and T2 and no significant changes in the mandibular branch height, mandibular body length, condylar distance, and mandibular angle distance (p>0.05). The mandibular growth at the angel of mandible was statistically significant (p<0.05), but it was not clinically significant because the mean value of the growth was small (right: 0.416±0.986 mm, left: 0.328±0.886 mm). No effect of age and gender on mandibular development was observed. ConclusionThe mandibular morphology was stable during preoperative orthodontic treatment in patients at the late adolescent stage. This study provides evidence for the possibility of early implementation of preoperative orthodontics.

Are We Correctly Measuring Mandibular Stability After Surgery-First Approach? A Comparative Study Based on Novel 3-Dimensional Measurements.

Using traditional measures to assess mandibular stability after the surgery-first approach (SFA) may produce inaccurate results because unlike the conventional orthodontic-first approach (OFA), the main dental movements occur after surgery in SFA, which produce unavoidable mandibular movements, especially in cases with postsurgical premature dental contact. As these movements are part of the surgical-orthodontic plan, they should not be considered an actual relapse. In this study, to avoid postsurgical dental movement effects, the authors used the relationship between proximal and distal mandibular segments to evaluate stability after SFA. Four easily located points on computerized tomography/cone-beam computerized tomography reconstructed 3-dimensional images were used to calculate 4 measurements between proximal and distal mandibular segments across the osteotomy line in two matched groups of patients (SFA and OFA) at 3 different time points (before, immediately after, and 1 year after the surgery). A high level of skeletal stability was found in the SFA group, with changes 1 year after surgery not exceeding 0.5mm. The SFA was as skeletally stable as OFA, and the mandibular counterclockwise rotation after surgery was related to the planned dental movements and not the instability of the surgery itself. To avoid the illusion of this preplanned relapse, stability should be measured as a relation between proximal and distal mandibular segments, across the osteotomy and fixation line, and not as a relation between maxillary and mandibular landmarks or between the mandible and facial planes as classically described.

Fresh–Frozen Allogenic Bone Graft Usage in Treatment of an Odontogenic Keratocyst in the Mandible

There are many cysts and tumors which might occur in the mandibular and maxillary bones. Their origin can be either odontogenic or non-odontogenic. One of the most common odontogenic cysts is the odontogenic keratocyst (OKC). Its nomenclature and classification have changed many times over years, from a tumor to, finally, a cyst. Nowadays, its treatment has not greatly changed, however, it is related to a potential recurrence rate more than any other cyst of odontogenic origins. OKC size, localization, and possible cortical expansion towards adjacent soft tissues might influence the scope of treatment and possible reoccurrence in time. Each case is quite individual, and after removal of the pathology in some cases there can be a necessity for either bone grafting or any other reconstruction method to restore proper bone continuity. The size and the placement of OKC might influence pathological fracture occurrence or inappropriate healing if the bone cavity after cyst removal is not properly treated. A good healing potential can be achieved with xenograft bone substitutes or allograft fresh–frozen bones. On rare occasions, a titanium plate is used to ensure mandibular stability. In the following case report, an atypical case of a large OKC treated with fresh–frozen bone grafts, supported with collagen barrier material in the anterior mandible with buccal cortical expansion, will be presented.

Mandibular stability and condylar changes following orthognathic surgery in mandibular hypoplasia patients associated with preoperative condylar resorption.

To evaluate postoperative mandibular stability and condylar changes in patients with mandibular hypoplasia and preoperative condylar resorption (CR) undergoing orthognathic surgery. Fifty-four patients were included in this retrospective study. Computed tomography (CT) scans were acquired preoperatively (T0), 2-7days immediate postoperatively (T1), and at least 1year postoperatively (T2). Three-dimensional (3D) cephalometric analysis and measurements of condylar angle, volume, and position (joint spaces) were performed. A 2-mm mandibular relapse was deemed clinically acceptable. We also analyzed the correlations between relapse and postoperative CR and susceptible factors using a multivariate logistic regression model. The results showed one year after the surgery, the average mandibular relapse was 1.0mm (p < 0.05), and the average reduction of condylar volume was 152.4 mm3 (12.7%). Condyle-fossa relationships were improved immediately after the surgery, with a tendency of returning to their original state in the follow-up (p < 0.05). Anteroposterior advancement at point B (B-CP advancement) at T1 and superior joint space (SJS) at T0 were significantly correlated with mandibular relapse, and postoperative CR was mainly associated with vertical increasement at point B (B-AP increasement) at T1. The optimal cut-off values were as follows: 1.6mm for SJS, 4.2mm for B-CP advancement, and 1.8mm for B-AP increasement. Concomitant advancement Genioplasty showed no significant correlation with relapse and postoperative CR. While patients with mandibular hypoplasia and preoperative CR were vulnerable to further condylar resorption after mandibular advancement, the treatment outcomes were generally clinically acceptable. Postoperative relapse was associated with a larger than 4.2mm of mandibular advancement measured at B-CP and a larger than 1.6mm of superior joint space measured at SJS, and postoperative CR was associated with a larger than 1.8mm of mandibular vertical increasement measured at B-AP. The findings of this study suggested that the mandibular advancement might be limited to 5mm for patients with preoperative CR. A concomitant advancement genioplasty might also be considered to achieve a better facial profile in these patients.

Is There Any Differences in Dento-Skeletal Stability between One Vs. Three-Screw Fixation of Mandible Following Bilateral Sagittal Split Osteotomy (BSSO)?

Background:The aim of this study was to compare the dento-skeletal stability between one and three-screw fixation of mandible following bilateral sagittal split osteotomy (BSSO) in skeletal class 3 patients.Methods:Healthy patients with skeletal class 3 malocclusion in Mashhad, Iran, from August 2020 to May 2021 were undergone mandibular setback through bilateral sagittal split osteotomy. Rigid fixation was performed in one group with one-screw technique, and three-screw fixation was done in another group. Cephalogram x-rays were prepared and analyzed in three stages: before surgery (T0), one week after the surgery (T1), and six months postoperatively (T2). The linear and angular alterations of chosen multivariate skeletal and dental variables were evaluated and statistically compared in all three periods. Results:This study included a total of 20 patients, 12 of them were female (60%). Patients in the one-screw fixation group had a mean age of 20.6 ± 2.2 years old, whereas those in the three-screw fixation group were 21.5 ± 2.8 years old, with no statistically significant difference. Both groups had excellent mandibular stability six months following surgery. No statistically significant differences were observed in the postoperative skeletal and dental changes between the two techniques.Conclusion:Fixation of the mandible following the setback surgery by the BSSO technique with the one-screw fixation method may be accomplished effectively, and the therapeutic outcomes are comparable to those obtained with the traditional 3-screw fixation approach.

Favorable outcomes within a comprehensive therapeutic rehabilitative program in a complex case of severe polytrauma

A polytrauma patient after a car accident represents a challenge for the health care system due to the multiple traumatic injuries, at least one of them potentially being life threatening. Many of these injuries require intense nursing and rehabilitation treatment, because some of them can cause permanent disability, affecting the patient’s future quality of life. Materials and methods: With the permission of the THEBA Ethics Committee (no 24389 / 28.06.2021), this paper presents a case of a 37-year-old patient with a severe polytrauma due to a car accident (driver), occurred on October 18, 2020. The patient was hospitalized in the Intensive Care Unit of the Emergency County Hospital of Targoviste, in a severe condition, being orotracheal intubated and having a thoracic polytrauma (multiple bilateral costal fractures, anterior-superior flail chest with acute respiratory failure) and mandible fracture. After clinical and hemodynamic stabilization, he was transferred to Bucharest Emergency University Hospital and after specific paraclinical investigations, he was surgically treated with thoracic fixation with metal plates, sternal fixation with plate and screws, thoraco-abdominal skin grafting and mandibular stabilization. Afterwards he was transferred to THEBA at the Plastic Surgery Clinic Department for lumbar-sacral pressure sore, where he suffered multiple surgical interventions. In our Neuromuscular Rehabilitation Department, the patient was admitted in 16.02.2021 with pain and severe functional impairments in the right elbow and the right knee, surgically treated sacral pressure sore still in the process of healing and having a severe deficiency of self-care and locomotion. He initially followed a rehabilitative nursing program and continued with a recovery therapy according to clinical stages. The patient was functionally assessed using the following scales: Medical Research Council (MRC) Scale for Muscle Strength, Functional Independence Measure (FIM), Life Quality Assessment (QOL), FAC International Scale and Independence Assessment Scale in Daily Activities (ADL/IADL). Results: Although the patient's evolution was slow, he had favorable outcomes with an increase in the scores of the evaluated scales at discharge. He benefited from specific surgical care of the pressure sores and a complex neuro-muscular rehabilitative program. The patient’s final performance in our clinic was walking on medium distances with support from another person. Conclusion: The multidisciplinary team approach with the addition of complex nursing measures and a personalized rehabilitative program for a young patient with polytrauma caused by a car accident established neuro-locomotor improvements which led to an increase in patient’s quality of life. Keywords: neuro-muscular rehabilitation, polytrauma

A cyst-like erosion in the mandibular condyle associated with malocclusion and its healing process in an 8-year-old patient: A case report

The etiology of temporomandibular joint disorders (TMDs) is multifactorial. Occlusal discrepancy is one of the predisposing factors for TMD development. This case report describes the healing process of a cyst-like erosion in the superior aspect of the condyle with pain attributable to occlusal discrepancy. The patient was an 8-year-old boy who presented with a posterior crossbite and pain in his right temporomandibular joint. Pretreatment cone-beam computed tomography revealed a cyst-like erosion in the superior aspect of the right condyle. Splint therapy was performed to determine whether there was a relationship between the posterior crossbite and joint pain using a mandibular stabilization splint. During splint therapy, the pain was relieved, and an occlusal interference appeared on the maxillary left lateral incisor, which was responsible for the lateral shift of the mandible and posterior crossbite. The cone-beam computed tomography images acquired over 2 years showed repair of the affected condyle. As shown in this patient, stabilizing the condylar position is one of the methods to determine the relationship between TMD and occlusion.

Skeletal stability after bimaxillary surgery with surgery-first approach for class III asymmetry is not related to virtual surgical occlusal contact.

Surgery-first orthognathic surgery is rarely used in class III asymmetry due to concerns of reduced skeletal stability from unstable surgical occlusion. This study aimed to evaluate if skeletal stability after surgery-first orthognathic surgery is related to virtual surgical occlusal contact or surgical change. We studied 58 adults with class III asymmetry, consecutively corrected by Le Fort I osteotomy and bilateral sagittal split osteotomy using a surgery-first approach. Dental casts were manually set to measure virtual surgical occlusal contact including contact distribution, contact number, and contact area. Cone-beam computed tomography taken before treatment, 1-week post-surgery, and after treatment was used to measure surgical change and post-surgical stability of the maxilla and mandible in translation (left/right, posterior/anterior, superior/inferior) and rotation (pitch, roll, yaw). The relationship between skeletal stability and surgical occlusal contact or surgical change was evaluated with correlation analysis. Significant instability was found in the mandible but not in the maxilla. No correlation was found between the maxillary or mandibular stability and surgical occlusal contact (all p > 0.01). However, a significant correlation was found between the maxillary (roll and yaw) or mandibular (shift, roll and pitch) stability and its surgical change (all p < 0.001). In correction of class III asymmetry with surgery-first bimaxillary surgery, the skeletal stability is not related to the virtual surgical occlusal contact, but surgical skeletal change. Planned over-correction is a reasonable option for correction of severe shift or roll mandibular asymmetry in bimaxillary surgery for class III deformity.

Edentulous Patient Satisfaction with Conventional Complete Dentures

Background and Objectives: Edentulism is considered to be an impediment impacting both patients’ quality of life and their nutrition. Conventional complete dentures are still a preferred treatment. However, there is no consensus on the most important factors which could substantially reduce the risk of patient dissatisfaction. This study evaluated the following determinants concerning patient satisfaction with complete maxillary and mandibular dentures: sex, denture-related functional and aesthetic aspects, and the degree of bone resorption. Materials and Methods: This study included 70 patients aged 34–81 years of age. All complete dentures were made by following the same technology. Visual analogue scales were used to assess patients’ overall satisfaction with dentures, comfort, ability to speak and chew, denture aesthetics, stability, and ease of prosthesis cleaning. Satisfaction with upper and lower dentures was rated separately. The degree of bone resorption was classified by using the Kalk and de Baat (1989) method. Results: The mean (SD) age of the study participants was 67.3 (10.4) years; 65.7% (n = 46) were females and 34.3% (n = 24) were males. There were no significant sex-based differences in resorption of the maxilla or mandibula. There were significant differences between maxillary and mandibular dentures, with lower mean satisfaction scores concerning chewing and maxillary complete dentures, and in regard to stability and comfort for mandibular complete dentures. There was a non-significant overall lower satisfaction with increased age. In multivariate analysis for mandibular complete dentures, aesthetics and stability significantly predicted the patient’s comfort levels, and the patient’s comfort significantly predicted overall satisfaction. For maxillary complete dentures, patient comfort and aesthetics significantly predicted overall patient satisfaction. Conclusions: Age, sex, and degree of resorption were not associated with patient satisfaction with complete dentures. Overall, patient satisfaction with both maxillary and mandibular complete dentures was related to their comfort level and denture aesthetics, and patient comfort itself was associated with stability of the mandibular denture.

Effect of Class II elastics on different mandibular arch preparation stabilized with aligners and stainless-steel wires: AFEM study.

Finite element models that simulate the effects of class II elastics on the mandibular arch in six different scenarios, using various immobilization methods of the posterior dentition, were studied. Per-element distribution of linear elastic stress-strain and total displacement was computed. Maximum strain on the PDL and maximum stress on alveolar bone increased with posterior tip-back and with the use of archwires vs. aligners. The configuration of the dentition affects the performance of aligners. They perform best on an unlevelled mandibular arch. Applying class II elastics results in vertical side effects that can be modulated by various mandibular stabilization methods. This is likely to be clinically relevant for high-angle patients and may explain the differing effects on the facial profile observed using various treatment modalities. 1-Increasing mandibular molar tip-back generally resulted in less eruption tendencies, with mandibular anchorage preparation resulting in the least amount of calculated vertical displacement. 2-Unexpectedly, with class II forces the use of aligner technology on an unlevelled curve of Spee resulted in improved vertical control when compared to aligner use on a levelled dentition. 3-Generally, using an archwire results in better transmission of stresses to adjacent teeth than the use of aligners. 4-Simulating interarch elastics requires implementing a medial component/orientation of the forces to better emulate clinical situations. 5-A hypothetical configuration: 15o tip-back of the mandibular second molar and aligner stabilization displayed the least amount of vertical movement and the most forward horizontal movement of the 2nd molar.

COMPLICATIONS OF RECONSTRUCTION PLATE INSTALLATION IN MANDIBULAR

Background: Mandibular resection will cause mandibular stability disturbance due to loss of some part of the bone. Instability of the mandible can cause aesthetic, physiological, and psychological malfunction. Installment of mandibular reconstruction plat on the remaining mandibular using screws were suggested to restore its stability. However, it is not uncommon that plat exposure occurs following mandibular reconstruction, caused by inaccurate adaptation of the plats to the mandibular bone. The aims of this report are to describe the various complications and managements after jaw resection and reconstruction with plates. Case Report: A 44 years old male patient complained the small defect in the chin, painless, and no fluid emited, accompanied by dermatitis. Intra oral examination showed no abnormalities. About 1 year ago the patient performed segmental resection of the mandible on the indication of ameloblastoma. The radiological x-ray showed all screw detached from the plat and radiolucent images appeared around the plat that attached to the mandible. The diagnosis was fistula at regio mentale, post resection and reconstruction surgery, suspected caused by titanium plate allergies. The provided therapies were fistulectomy, screw removal, and plate reconstruction. Post therapy conditions showed improvement and no patients complaints of pain. Conclusion: Plate exposure is a complication that can occur after the installation of the reconstruction plate, but besides that it can also cause an allergic reaction from the material used. Keywords: Complication, Mandibular Resection, Plate Reconstruction, Titanium Plate Allergies

Mandibular Stability After Sagittal Split Ramus Osteotomy With Hybrid Technique in Asymmetric Patients.

The hybrid technique after bilateral sagittal split ramus osteotomy is an internal fixation method using monocortical mini-plates and additional bicortical positional screws. In this study, we analyzed the postoperative stability of 23 patients with mandibular asymmetry who underwent bilateral sagittal split ramus osteotomy and hybrid fixation with or without LeFort I osteotomy. Anatomical landmarks of the deviated and non-deviated sides of the jaw were established to measure the angle and distance to the reference plane in three-dimensional cone beam computed tomography images. We analyzed the positional changes and correlations of the reference points at preoperative (T1), postoperative 2 weeks (T2), and postoperative 1 year (T3). There were significant differences in preoperative position of the upper and lower molar cervix alveolar crest to the reference plane (U6-X and L6-X) and the condylion angles between deviated and non-deviated sides. Postoperatively (T2-T3), each reference point had no statistically significant positional change. Pearson correlation coefficient between the amount of menton deviation (ME-X at T1) and positional change of menton after surgery (T2-T3) was 0.30, and P value was 0.168. The hybrid fixation technique is an effective fixation method for achieving postoperative stability for mandibular asymmetry.

Sequential Changes in Pharyngeal Airway Dimensions After Mandibular Setback Surgery and Its Correlation With Postsurgical Stability in Patients With Mandibular Prognathism

This study aimed to evaluate the sequential changes in the pharyngeal airway dimensions after mandibular setback surgery and to verify its correlation with postsurgical mandibular stability in patients with mandibular prognathism. This retrospective study included 28 patients with mandibular prognathism who underwent surgical orthodontic treatment and isolated mandibular setback surgery. Patients who had cone-beam computed tomography before surgery, immediately after surgery, at short-term follow-up (11.8 ± 5.1 months), and long-term follow-up (43.0 ± 13.1 months) were included. Airway dimensions, including distance, minimum cross-sectional area, and airway volume, were measured to evaluate the changes following mandibular setback surgery. With the measurements of postsurgical mandibular relapse, the relationship between sequential changes in airway dimensions and the mandible was verified using correlation analysis. Airway dimensions decreased immediately after mandibular setback surgery. The decreased airway dimensions recovered during short-term follow-up and maintained to the long-term follow-up. The mandible was set back 7.7 ± 5.1 mm at pogonion immediately after surgery. Postsurgical skeletal relapse was 1.1 mm at pogonion during short-term follow-up. During long-term follow-up, the mandible moved 0.4 mm anteriorly, which was about 50% of the changes during short-term follow-up. Statistically significant correlations were found between the sequential changes in airway dimensions and the postsurgical skeletal relapse. The decreased airway dimensions following mandibular setback surgery recovered during short-term follow-up and maintained to the long-term follow-up. Dimensional recovery of the pharyngeal airway was correlated with postsurgical skeletal relapse during the 1-year follow-up period.

Comparative stability and outcomes of two surgical approaches for correction of class III asymmetry with lip or occlusal cant.

To assess and compare the stability and outcomes of the two surgical approaches for patients with roll asymmetry. A total of 50 adult patients were consecutively recruited for this prospective study. Patients with class III asymmetry and lip or occlusal cant who underwent bimaxillary surgery were grouped according to surgical approach: asymmetric posterior impaction on both sides (API, n = 31) and posterior impaction on one side and posterior extrusion on the other side (PIE, n = 19). Postsurgical stability and outcomes between groups were determined with cone-beam computed tomography for facial midline, lip, and occlusal cant at 1 week (T1), and at least 12-month postsurgery (T2, completion of orthodontic treatment). Presurgery, the upper anterior occlusal cant and lip cant were significantly greater for the PIE group (p < 0.05). Postsurgery (T2), the mandible moved upward and rotated upward in both groups. However, the upward rotation was significantly greater in the PIE group compared with the API group. Although the two approaches resulted in significant improvements in facial symmetry, the deviation in the facial midline remained under-corrected for most API patients. Patient outcomes for mandibular stability and facial symmetry differed between the two surgical approaches for correction of class III asymmetry with lip or occlusal cant. The findings of this study suggest that planned over-correction is a reasonable option for the approach of asymmetric posterior impaction on both sides.

Comparison of 3-dimensional postoperative dental movement in Class III surgical correction with and without presurgical orthodontic treatment

BackgroundSurgery-first approach (SFA) is an emerging concept that surgically reposition the jaw bones without presurgical orthodontic treatment phase. The study investigated 3D dental movement in the postoperative orthodontic phase with orthodontic-first (OF) and SFA in orthognathic surgery (OGS). MethodsThis study included consecutive 40 patients (20, SF group; 20, OF group) skeletal Class III who underwent 2-jaw OGS correction. The data of cone-beam computed tomography were acquired at 3 stages with the scan of dental models to replace the dentition of the craniofacial images; at before OGS (T0), 1 week after OGS (T1) and at the completion of treatment (T2). The skeletal changes were obtained by overall superimposition. The post-operative dental movement was measured by 3D regional superimposition between T1 and T2. ResultsThere were no significant difference in the postsurgical orthodontic movement in both groups except significant upper and lower molars extrusion by 2 mm in the SF group. Both groups exhibited no significant difference in mandibular stability in sagittal and vertical directions. The amount of extrusion in the molars was correlated with a postoperative sagittal mandibular forward movement. The total treatment duration was significantly shorter 230 days in the SF group. ConclusionThe completion of the orthodontic treatment after OGS in the SFA was mainly accomplished through molar extrusive movement in both arches. The surgical setup of dental occlusion with 4 mm posterior open bite could be corrected during the postsurgical orthodontics in SFA through molar extrusion. The dental occlusion outcome was no different between OF and SFA.