Relation Between Masticatory Performance and Skeletal Properties in Patients With Skeletal Class III Malocclusion.

This study aimed to measure masticatory performance (MP) using ß-carotene gummy jelly to investigate its relationship with skeletal properties in decompensated patients diagnosed with skeletal class III malocclusion. The study included 78 patients (38 men and 40 women) diagnosed with skeletal class III malocclusion without temporomandibular joint disorder and periodontal disease. MP was measured using a new masticatory measuring device and ß-carotene in the gummy jelly. Lateral and posteroanterior cephalograms were obtained, and skeletal properties (Me deviation, ANB, SNB, APDI, Wits, ODI, facial axis, body length, ramus length, SN-GoGn, anterior facial height, posterior facial height, saddle angle, articular angle, and gonial angle) were evaluated. MP differences according to age and sex and the effect of skeletal properties on MP were analyzed using multiple linear regression analysis. The MP of all patients was 3690.55±1428.77 mm², MP of the male group was 4043.05±1498.09 mm², and MP of the female group was 3355.68±1272.19 mm². Among the items investigated, the variable that affected MP was posterior facial height. Posterior facial height showed a positive correlation (P=0.022). There was no significant difference between MP and other skeletal properties (P>0.05). The severity of the hypodivergency in skeletal class III could affect MP. The relationship between facial asymmetry or skeletal relation and MP could not be explained in this study.

Zygoma Augmentation With 3D Printed Bioactive Glass-Ceramic Implant.

ABSTRACT: Zygoma, which is located at the middle third of the face, has a significant impact on the facial impression with its volume and prominence. CaO-SiO 2 -P 2 O 5 -B 2 O 3 glass-ceramics (BGS-7) has been reported as a new alternative of nonresorbable bone grafting material, which has bioactivity of inducing human osteoblast between bone and implant, resulting integration to the bone. Furthermore, its chemical characteristics are similar to bone, resulting in radiopacity with no metallic artifact on the radiographic images. With the development of Computer aided design-Computer aided manufacturing technology, BGS-7 can be manufactured into a patient-specific design.During follow-up periods, 3D printed BGS-7 implant did not displace from the initial recipient site. By cone-beam computed tomography evaluation, a gap between bone and BGS-7 was filled with the radiopacity, which implied bony fusion. Consequently, this clinical case shows that the BGS-7 implant could be an effective and safe graft material for zygoma bone defects.

Four Different Reasons of Subcutaneous Emphysema With or Without Pneumomediastinum and Pneumothorax After Facial Bone Surgery.

ABSTRACT: In the present study, the authors report rare case series with subcutaneous emphysema with or without pneumomediastinum and pneumothorax after orthognathic and facial bone contouring surgery, compare their clinical and radiologic findings, and suggest precautions. Four patients who showed subcutaneous emphysema on follow up chest X-ray and computed tomography after orthognathic and facial bone contouring surgery were included in the study. In all cases post-op subcutaneous emphysema were detected, however, the aspect and mechanisms of post-op air spread were all different. After the conservative management with administering the O 2 by nasal cannula or endotracheal tube, the symptoms were relieved except 1 patient who needed chest tube insertion and further supra-sternal incision. In conclusion, subcutaneous emphysema with or without pneumomediastinum and pneumothorax after orthognathic and facial bone contouring surgery can be occurred by cervical fascia injury or alveolar ruptures. To preventing those complications, traumatic naso-tracheal intubation, excessive positive pressure ventilation, intermaxillary fixation immediate after the surgery, and increase of intra-alveolar pressure of the patients should be avoided.

Soft tissue expander for vertically atrophied alveolar ridges: Prospective, multicenter, randomized controlled trial.

OBJECTIVES: Conventional guided bone regeneration (GBR) limits the amount of bone graft due to limited soft tissue expansion. We hypothesize that the use of tissue expander will successfully augment soft tissue prior to bone graft, allowing for sufficient amount of grafting which will lead to a more stable and effective vertical bone graft. The authors aimed to evaluate effectiveness of the novel self-inflating tissue expander for vertical augmentation in terms of soft tissue expansion, clinical outcomes, and related complications. MATERIAL AND METHODS: A prospective, multicenter, randomized controlled trial was performed on patients requiring vertical augmentation. For experimental group patients, the tissue expander was subperiosteally implanted and followed by a tunneling bone graft without full flap reflection. Control patients underwent conventional vertical GBR. Primary objectives were to evaluate the dimensional changes of soft tissue and radiographic vertical bone gain and retention. As a secondary outcome, clinical complications and thickness changes of expanded overlying tissue were assessed and analyzed. RESULTS: Twenty-three patients in each group were included. During a 4-week expansion, two of the experimental group showed over-expansion and one showed mucosal perforation associated with previous severe scars. The other patients showed uneventful expansion and mean tissue augmentation was 6.88 ± 1.64 mm vertically. Ultrasonographic measurements of overlying gingiva revealed no thinning after tissue expansion (p > .05). Significantly higher vertical bone gain was shown in the experimental group (5.12 ± 1.25 mm) compared with that in the control patients (4.22 ± 1.15 mm; p < .05). After a 6-month retention period, the mean vertical bone measurement of the controls had decreased to 1.90 mm (55.0% reduction), which was a significantly greater decrease than that in the experimental group (mean 3.55 mm, 30.7% reduction; p < .05). CONCLUSION: Our results demonstrated the effectiveness of tissue expanders followed by tunneling bone graft for vertical augmentation; however, studies comparing the two techniques without tissue expanders are needed to elucidate the net effect of tissue expansion.

Comparison of Lip Line Cant Change After 1-Jaw and 2-Jaw Surgery.

OBJECTIVES: The purpose of this study was to compare the lip line cant (LLC) changes after 1 and 2-jaw surgery, and to evaluate the correlations of the craniofacial factors affecting LLC. METHODS: The study subjects were selected (LLC amount within 1.5-6.0°) from among the patients diagnosed with Class III malocclusion who underwent one (n = 20) or 2-jaw surgery (n = 20). Cone beam computed tomography images were obtained immediately before the operation (T1) and 6 months after the operation (T2). Preoperative and postoperative craniofacial measurements were obtained. RESULTS: The study subjects showed 3.12° LLC on average before undergoing 1-jaw surgery, and their LLC changed to 1.27° after the surgery. As for 2-jaw surgery, the subjects showed 3.38° LLC on average before the surgery and 0.98° after the surgery. LLC at pre-treatment may be more affected by a cant of the occlusal plane in the mandible than maxilla. In the comparison of the value of changes of LLC, the value of 2-jaw surgery was bigger than the value of 1-jaw surgery but the difference was statistically insignificant. LIMITATIONS: This study had a limitation in that the muscles were not considered. And the metal bracket or metal crown and bridge, however, can cause noise and blurring artifacts in CT, which can lead to a low resolution. And the limited number of the patients should be considered. CONCLUSIONS: In correlation analysis, both pre-surgery LLC and change of LLC have correlation with almost all the craniofacial measurement. Lip-line cant of patients with facial asymmetry has higher correlation with mandibular cant than with other cants. To improve the LLC, a surgical plan should be established to minimize the mandibular cant using the computer simulation as well as the maxillary cant.

Factors associated with spontaneous angular changes of impacted mandibular third molars as a result of second molar protraction.

INTRODUCTION: This study aimed to identify significant factors affecting the spontaneous angular changes of impacted mandibular third molars as a result of second molar protraction. Temporary skeletal anchorage devices in the missing mandibular first molar (ML-6) or missing deciduous mandibular second molar (ML-E) with missing succedaneous premolar spaces provided traction. METHODS: Forty-one mandibular third molars of 34 patients (10 male and 24 female; mean age 18.3 ± 3.7 years) that erupted after second molar protraction were included in this study. They were classified into upright (U) and tilted (T) groups. Linear and angular measurements were performed at the time of treatment initiation (T1) and of ML-6 or ML-E space closure (T2). Regression analyses were used to identify significant factors related to third molar uprighting. RESULTS: Nolla stage (odds ratio [OR] 4.1), sex (OR 0.003 for male), third molar angulation at T1 (OR 1.1), missing tooth space (OR 0.006), rate of third molar eruption (OR 23.3), and rate of second molar protraction (OR 0.2) significantly affected third molar uprighting. Age, third molar angulation at T1, rate of third molar eruption, and rate of second molar protraction were significant factors for predicting third molar angulation at T2. CONCLUSIONS: Available space for third molar eruption before and after second molar protraction is not associated with uprighting of erupting third molars. Older patients whose third molars are in greater Nolla stage, are in a more upright position at T1, and have a greater eruption rate have a greater chance for third molar uprighting. Alternatively, an increase in second molar protraction rate results in mesial tipping of the third molars.

Occlusion-Fit Three-Dimensional-Printed Zygoma Repositioner.

Reduction malarplasty is utilized to reshape the facial form into an oval shape. However, complications and unfavorable results in reduction malarplasty have been reported. Reoperation of a nonunion malar complex is difficult relative to the achievement of a satisfactory outcome using the intraoral approach with a narrow surgical field because the normal anatomy has been destroyed, and previous surgery may have caused asymmetry. In this situation, computer-aided simulation surgery and surgical guides can serve as effective solutions to overcome the limitations of reoperative malarplasty using the intraoral approach.In this report, the authors present a case with successful treatment outcomes for a nonunion malar complex using a three-dimensional-printed zygoma repositioner.

Cleft Alveolus Reconstruction Using a Three-Dimensional Printed Bioresorbable Scaffold With Human Bone Marrow Cells.

Bone tissue engineering technology based on scaffold has been applied for cleft lip and palate treatment. However, clinical applications of patient-specific three-dimensional (3D) scaffolds have rarely been performed. In this study, a clinical case using patient-specific 3D-printed bioresorbable scaffold with bone marrow stromal cells collected from iliac crest in the operating room has been introduced. At 6-month after transplantation, the bone volume of the newly regenerated bone was approximately 45% of the total defect volume. Bone mineral density of the newly regenerated bone was about 75% compared to the surrounding bone. The Hounsfield unit value was higher than that of cancellous maxillary alveolar bone and lower than that of the cortical maxillary alveolar bone. Bone-marrow-derived mesenchymal stem cells-seeded 3D-printed patient-specific polycaprolactone scaffolds offer a promising alternative for alveolar cleft reconstruction and other bony defects.

Orthognathic surgery Deteriorates the osseointegration of dental implants: A propensity-matched multicentre cohort study.

This study aimed to investigate the possible influence of the regional acceleratory phenomenon (RAP) on dental implant osseointegration. Orthognathic surgery was set as an intervention for RAP, and a multicentre cohort study of two groups was undertaken. Group O included patients with single implant placement at least 4 months after orthognathic surgery and functional loading for more than 1 year, while controls (Group C) were without any major surgery. Clinical and radiographic assessments of implants, including changes in marginal bone levels, were analysed at baseline, 6- and 12-month follow-up. Bivariate analysis of two groups with propensity score matching was performed. After propensity score matching, all 10 confounding variables had acceptable standardised difference scores (<20%), indicating that the matching procedure had efficiently balanced the two groups. Following the propensity score adjustment, the marginal bone loss was significantly higher in Group O than the control at 6 months (1.66 ± 1.05 mm vs 0.59 ± 0.64 mm, P < 0.001) and 12 months (2.30 ± 1.27 mm vs 0.82 ± 0.78 mm, P < 0.001). Compared to Group C, subjects in Group O had a higher incidence of peri-implant mucositis and implantitis (11.8% vs 1.5%, P = 0.033). Impaired osseointegration of dental implants was associated with orthognathic surgery. Special considerations for peri-implant soft and hard tissue stability should be addressed to obtain ideal treatment results and prognosis for patients who have had prior orthognathic surgery.

Risk Factor Analysis of Graft Failure With Concomitant Cyst Enucleation of the Jaw Bone: A Retrospective Multicenter Study.

PURPOSE: Cysts are common pathologic entities in the oral and maxillofacial region. Enucleation is commonly used for treatment and is occasionally followed by bone grafting. However, no studies have evaluated factors affecting the failure of grafts used for cystic defects in the oral and maxillofacial region. Therefore, the present study was conducted to determine the risk factors for postoperative graft failure in patients treated with cyst enucleation and simultaneous bone grafting. MATERIALS AND METHODS: Clinical data for 305 patients who had undergone cyst enucleation with simultaneous bone grafting were retrospectively investigated in this multicenter case-and-control study. The predictor variables included host, pathologic, and treatment factors. The outcome variable was success or failure of the bone graft. Descriptive statistics were computed, and the P value was set at .05. RESULTS: Bone graft failure was observed in 48 cases. The mean duration from surgery to failure was 38.7 days. Multivariable logistic regression analysis showed a significant association between graft failure and younger age (odds ratio [OR] = 1.033; P = .016), smoking (OR = 2.598; P = .017), preoperative infection (OR = 4.660; P = .001), large cysts (OR = 1.052; P = .010), impaction of the mandibular third molar in the cystic cavity (OR = 3.021; P = .007), perilesional osteosclerosis (OR = 4.973; P = .001), and the use of mixed non-autogenous and autogenous bone grafts (OR = 3.891; P = .007). CONCLUSIONS: This study provides a list of important factors that should be considered by clinicians planning enucleation and simultaneous bone grafting for cysts in the oral and maxillofacial region.

Occlusion-Fit V-Line Guide and Gooseneck Saw for Safe and Accurate Mandibuloplasty in Asians.

BACKGROUND: A slender or slim face with narrow facial features is considered esthetically appealing in Asian people. Plastic surgery to obtain an oval face, called a 'V-line,' is popular among young people. MATERIALS AND METHODS: A total of 20 Korean patients were included in this study. The patients underwent mandibular anguloplasty with three-dimensional computer-aided design and manufacturing surgical guides that were accurately fitted to the upper and lower teeth, allowing for precise replication of a virtual surgery during a real surgical procedure. RESULTS: There were no significant complications, including severe bleeding, facial nerve injury, or airway obstruction. All patients were satisfied with the esthetic and functional results, except for one who was neutral toward the result. The mean satisfaction score was 4.75, which was between 'satisfied' and 'very satisfied.' CONCLUSION: The V-line guide and gooseneck saw allowed for safe and fast resection of bone in the mandibular angle area. This technique provides consistent results during surgery as well as minimizing surgical complications. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .

Simultaneous Bimaxillary Surgery and Mandibular Reconstruction With a 3-Dimensional Printed Titanium Implant Fabricated by Electron Beam Melting: A Preliminary Mechanical Testing of the Printed Mandible.

A woman presented with a long history of mandibular defects posterior to the left lower first premolar caused by inadequate reconstruction after removal of a tumor on the left side of the mandible. In the frontal view, extreme facial asymmetry was apparent. The dental midline of the mandible was deviated 10 mm to the left compared with the dental midline of the maxilla, and all maxillary teeth were inclined to the left owing to dental compensation. There was an 8-mm maxillary occlusal cant relative to the maxillary first molar. Bimaxillary surgery using computer-assisted designed and computer-assisted manufactured devices without an intermediate occlusal splint was performed to align the maxilla and mandible at the correct position, and reconstructive surgery for the mandible using a 3-dimensional printed titanium mandible was concurrently performed. In particular, during the virtual mandible design, 2 abutments that enabled the prosthetic restoration were included in the mandible using a computer-assisted design program. This report describes the successful functional and esthetic reconstruction of the mandible using electron beam melting technology, an alternative technique for reconstruction of mandibles that did not undergo radiation therapy.

Keyhole System: A Computer-Assisted Designed and Computer-Assisted Manufactured Maxillomandibular Complex Repositioner in Orthognathic Surgery.

Currently, virtual orthognathic surgery using the CAD/CAM program and three-dimensional printing technology has provided a valuable tool supporting accurate surgical planning and precise surgery. However, despite the advancements in CAD/CAM virtual surgical planning, accurately reproducing surgical planning from a virtual surgery to the operating field is still challenging. Here, we report the Keyhole system as a method that has constantly provided us with consistent results during double-jaw surgery, especially during this age of ever increasing aesthetic demand from patients.

Partially Withdrawn Nasotracheal Tube: An Alternative to the Nasal Trumpet.

After 2-jaw surgery, difficulty in breathing through the mouth and the nose is common due to nasal airway obstruction, intraoral bleeding, and sometimes maxillomandibular fixation. A partially withdrawn nasotracheal tube can be used economically with equal efficacy to the nasopharyngeal airway to provide supplemental oxygen after 2-jaw surgery.

Simultaneous premaxillary repositioning and cheiloplasty in adult patients with unrepaired bilateral cleft lip and palate.

Primary cheiloplasty in adult patients with unrepaired complete bilateral cleft lip and palate is quite challenging due to severe premaxillary anterior projection. To get the best repair results, the author carried out repositioning of the premaxilla and repair of the lip deformity in a single stage. Positive results for the primary lip repair and appropriate repositioning of the premaxilla were achieved. No avascular necrosis of the premaxilla was observed. Repositioning of the premaxilla and repair of the lip deformity in a single operation appears to be a reliable method for treating adult patients with previously unrepaired or poorly repaired bilateral cleft lip and palate.

Vertical augmentation of a severely atrophied posterior mandibular alveolar ridge for a dental implant using a patient-specific 3D printed PCL/BGS7 scaffold: A technical note.

Vertical bone augmentation for dental implants in the posterior mandibular region with significant bone resorption is challenging. For this purpose, methods such as block bone grafting with screw fixation, particulate bone grafting with titanium mesh or barrier membrane, and distraction osteogenesis have been used, and autogenous block bone grafting is considered the gold standard. However, the autogenous block bone grafting has the following disadvantages: bone harvesting is challenging, and block bone contouring according to the recipient site is time-consuming and laborious. Therefore, in this study, we report the use of particulate bone with a polycaprolactone/bioactive glass-7 scaffold, designed, and three-dimensionally printed preoperatively, to resolve the above-mentioned challenges.

Reconstruction of maxillofacial bone defects using patient-specific long-lasting titanium implants.

The objective of this retrospective study is to verify the effectiveness and safety of patient-specific titanium implants on maxillofacial bones, with a long-term follow-up. Total 16 patients with various maxillofacial defects underwent reconstruction using patient-specific titanium implants. Titanium implants, manufactured by electron beam melting, selective laser sintering, or milling, were inserted into the maxilla, mandible, or zygoma. Long-term follow-up (36.7 ± 20.1 months) was conducted after the surgery. Bone fusion of the titanium implant body, postoperative infection, implant malunion, functional results, patient satisfaction, subsidence, osteolysis around the implants, and complications were recorded and analyzed at the last follow-up. Of the 28 implants, only one failed to unite with the bone; therefore, revision surgery was performed. No osteolysis or subsidence around the titanium implants nor adverse events were observed; the mean VAS score for satisfaction was 9. All patients enrolled in this trial were esthetically and functionally satisfied with their surgical results, and fixation failure and esthetic dissatisfaction complications were well resolved. Patient-specific titanium showed satisfactory outcomes when used to treat various oral and maxillofacial defects. A 3D printed titanium implant can be effectively used in the reconstruction of the zygoma and mandible instead of autogenous bone without donor site morbidity.

A Novel Device for Blood Drainage after Le Fort I Osteotomy: Maxillary Sinus Ventilation Drainage (MSVD).

The purpose of this study is to present a novel maxillary sinus ventilation drainage (MSVD) device which facilitates blood drainage and nasal breathing after Le Fort I osteotomy. One hundred patients who underwent bimaxillary orthognathic surgery from January 2016 to June 2016 at the Department of Oral and Maxillofacial Surgery, Chung-Ang University Hospital were retrospectively selected and divided into two groups. MSVD was applied in 50 patients, who were allocated to the MSVD group, while the remaining 50 patients, in whom MSVD was not applied, were allocated to the non-MSVD group. All patients underwent a cone-beam computed tomography (CBCT) scan before and 2 days after surgery. CBCT was used to analyze middle meatus patency and the percentage of hematoma volume per entire maxillary sinus volume. Statistical comparisons between the two groups were performed using the Chi-squared and Mann-Whitney U tests to investigate the clinical effectiveness of MSVD. The MSVD group showed significantly higher maintenance ratio of the middle meatus patency and a higher percentage of maxillary sinus air volume (p < 0.05) than the non-MSVD group. MSVD facilitated nasal breathing after Le Fort I osteotomy by reducing hematoma inside the maxillary sinus and promoting middle meatal patency.

A new rationale for preservation of the mandibular third molar in orthognathic patients with missing molars.

Controversies exist regarding the need for prophylactic extraction of mandibular third molars in patients who plan to undergo orthognathic surgery. An 18-year-old male patient was diagnosed with mandibular prognathism and maxillary retrognathism with mild facial asymmetry. He had a severely damaged mandibular first molar and a horizontally impacted third molar. After extraction of the first molar, the second molar was protracted into the first molar space, and the third molar erupted into the posterior line of occlusion. The orthognathic surgery involved clockwise rotation of the maxillomandibular complex as well as angle shaving and chin border trimming. Patients who are missing or have damaged mandibular molars should be monitored for eruption of third molars to replace the missing posterior tooth regardless of the timing of orthognathic surgery.

Osseointegration of 3D-printed titanium implants with surface and structure modifications.

BACKGROUND: The purpose of this study was to establish a mechanical and histological basis for the development of biocompatible maxillofacial reconstruction implants by combining 3D-printed porous titanium structures and surface treatment. Improved osseointegration of 3D-printed titanium implants for reconstruction of maxillofacial segmental bone defect could be advantageous in not only quick osseointegration into the bone tissue but also in stabilizing the reconstruction. METHODS: Various macro-mesh titanium scaffolds were fabricated by 3D-printing. Human mesenchymal stem cells were used for cell attachment and proliferation assays. Osteogenic differentiation was confirmed by quantitative polymerase chain reaction analysis. The osseointegration rate was measured using micro computed tomography imaging and histological analysis. RESULTS: In three dimensional-printed scaffold, globular microparticle shape was observed regardless of structure or surface modification. Cell attachment and proliferation rates increased according to the internal mesh structure and surface modification. However, osteogenic differentiation in vitro and osseointegration in vivo revealed that non-mesh structure/non-surface modified scaffolds showed the most appropriate treatment effect. CONCLUSION: 3D-printed solid structure is the most suitable option for maxillofacial reconstruction. Various mesh structures reduced osteogenesis of the mesenchymal stem cells and osseointegration compared with that by the solid structure. Surface modification by microarc oxidation induced cell proliferation and increased the expression of some osteogenic genes partially; however, most of the markers revealed that the non-anodized solid scaffold was the most suitable for maxillofacial reconstruction.