Classification of Skeletal Phenotypes of Adult Patients With Cleft Skeletal Class III Malocclusion Using Principal Component Analysis and Cluster Analysis.

The purpose of this study was to classify the skeletal phenotypes of adult patients with skeletal class III (C-III) malocclusion and unilateral or bilateral cleft lip and palate using principal component analysis and cluster analysis. The samples consisted of 81 adult C-III patients with cleft lip and palate (CLP) who underwent orthognathic surgery (OGS) or distraction osteogenesis (59 males and 22 females; 50 unilateral cleft lip and palate and 31 bilateral cleft lip and palate; mean age when lateral cephalograms were taken, 22.2±4.6 y). Thirteen angular and one ratio cephalometric variables were measured. Using 4 representative variables obtained from principal component analysis (SNA, SNB, Gonial angle, and Bjork sum), K-means cluster analysis was performed to classify the phenotypes. Then, statistical analysis was conducted to characterize the differences in the variables among the clusters. Five clusters were obtained from 3 groups: severely retrusive maxilla and moderately retrusive mandible group: cluster-1 (23.5%, severely hyperdivergent pattern), cluster-4 (27.2%, moderately hyperdivergent pattern), and cluster-5 (11.1%, normodivergent pattern); moderately retrusive maxilla and normal mandible group: cluster-2 (30.9%, normodivergent pattern); normal maxilla and moderately protrusive mandible group: cluster-3 (7.4%, normodivergent pattern). Although skeletal phenotypes were diverse, distribution of sex and cleft type did not differ among 5 clusters ( P >0.05). Sixty-two percent of cleft patients showed a severely retrusive maxilla and moderately retrusive mandible (cluster-1, cluster-4, and cluster-5), which indicated that these are the main cause of skeletal C-III malocclusion in CLP patients who were treated with OGS. Therefore, it is necessary to consider presurgical orthodontic treatment and surgical planning based on the skeletal phenotypes of CLP patients.

Facial Asymmetry Phenotypes in Adult Patients With Unilateral Cleft Lip and Palate and Skeletal Class III Malocclusion Using Principal Component Analysis and Cluster Analysis.

The purpose of this study was to classify and characterize facial asymmetry (FA) phenotypes in adult patients with unilateral cleft lip and palate (UCLP) and skeletal class III malocclusion. The samples comprised 52 adult UCLP patients (36 men and 16 women; mean age, 22.43 y) who had undergone orthognathic surgery for correction of class III malocclusion. After measurement of 22 cephalometric parameters in posteroanterior cephalograms taken 1 month before orthognathic surgery, principal component analysis was performed to obtain 5 representative parameters [deviation (mm) of ANS (ANS-dev), maxillary central incisor contact point (Mx1-dev), and menton (Me-dev); cant (degree) of the maxillary anterior occlusal plane (MxAntOP-cant) and mandibular border (MnBorder-cant)]. K-means cluster analysis was conducted using these representative parameters. The differences in cephalometric parameters among the clusters were statistically analyzed. The FA phenotypes were classified into 4 types: No-cant-and-No-deviation type (cluster-4, n=16, 30.8%); MxMn-cant-MxMn-dev to the cleft-side type (cluster-3, n=4, 7.7%); Mx-cant-Mn-shift to the cleft-side type (cluster-2, n=15, 28.8%); and Mn-cant-Mn-dev to the noncleft-side type (cluster-1, n=17, 32.7%). Asymmetry in the maxilla and/or mandible were observed in 70% of patients. One third of patients (cluster-2 and cluster-3; sum, 36.5%) exhibited significant cant of MxAntOP induced by cleft and cant or shift of the mandible to the cleft side. Another one third of patients (cluster-1, 32.7%) demonstrated significant deviation and cant of the mandible to the noncleft-side despite cleft in the maxilla. This FA phenotype classification might be a basic guideline for diagnosis and treatment planning for UCLP patients.

What Are the Contributing Factors for Postsurgical Relapse After Two-Jaw Surgery in Patients With Cleft Lip and Palate.

The purpose of this study was to investigate the amount and pattern of postsurgical relapse after 2-jaw surgery in cleft lip and palate patients in terms of the sagittal and vertical aspects. The samples consisted of 21 adult patients who had the similar initial skeletodental pattern before surgery and underwent 2-jaw surgery. They were divided into high relapse (n = 11) and low relapse groups (n = 10) (criteria, 30% forward relapse of the B point). After the cephalometric variables of cephalograms taken at 1 month before surgery (T0), immediately after surgery (T1), and at least 1 year after surgery (T2) were measured, the Wilcoxon test, Mann-Whitney U test, and Pearson correlation test were performed for statistical analysis. When compared with the low relapse group, the high relapse group exhibited significant counterclockwise rotation of the distal segment of the mandible resulting in more forward movement of the mandible and significant labioversion of the maxillary incisors during T1-T2. The amount of postsurgical relapse of the mandible had a positive relationship with the amounts of setback and clockwise rotation of the mandible with surgery. In addition, the more decrease in overbite through surgery occurred, the more relapse (forward movement of the mandible) produced. Therefore, for the prevention of significant postsurgical relapse of the mandible in cleft patients, it is necessary to reduce unnecessary clockwise rotation of the mandible and to increase the vertical stability of maxilla during orthognathic surgery.

Three-dimensional virtual-surgery simulation-assisted asymmetric bilateral mandibular distraction osteogenesis for a patient with bilateral condylar fractures.

INTRODUCTION: Our objective was to report a patient treated with 3-dimensional virtual-surgery simulation-assisted asymmetric bilateral mandibular distraction osteogenesis. METHODS: A boy (age, 9.5 years) had mandibular hypoplasia and facial asymmetry, induced by bilateral condylar fractures at 4 years of age. The asymmetric bilateral mandibular distraction osteogenesis was planned to correct facial asymmetry and mandibular hypoplasia. The 3-dimensional virtual-surgery simulation results were 11 mm of horizontal distraction on the right side and 4.5 mm of horizontal and 18 mm of vertical distraction on the left side of the mandible. Bilateral ramus osteotomies were performed, and intraoral unidirectional distraction devices were inserted. After a 6-day latency period, distraction was performed at 1 mm per day, followed by a 5-month consolidation period. Transarch and interarch elastics and an acrylic plate were used during distraction and consolidation. Total treatment time was 30 months. RESULTS: Satisfactory outcomes were obtained (achievement ratios between postconsolidation results and simulated results: gonial angle, 106% and 103.9%; mandibular body length, 94.2% and 89.9%; ramus height, 104.1% and 94.5% [values of the right and left sides, respectively]). The chin-point deviation and the transverse cant of the maxillary occlusal plane were significantly improved (10.1 mm to 3.3 mm; -6.8° to -4.4°). At 53 months of follow-up, the Class I molar relationship was well maintained. The transverse cant of the maxillary occlusal plane was slightly improved to -3.7° during pubertal growth. CONCLUSIONS: Three-dimensional virtual-surgery simulation can help clinicians to determine the optimal vector and amount of distraction with high accuracy in complex cases requiring simultaneous correction of a hypoplastic mandible and facial asymmetry.

Simultaneous inferior alveolar nerve regeneration and osseointegration with a nerve growth factor-supplying implant: a preliminary study.

PURPOSE: Although nerve growth factor (NGF) has been proved to enhance inferior alveolar nerve (IAN) regeneration, its clinical application remains a challenging issue. This study investigated the functional regeneration of IAN injury by supplying NGF using an NGF-supplying implant and its effect on the osseointegration. MATERIALS AND METHODS: In canine IAN transection-and-repair models (n = 9), NGF-supplying implants connected to osmotic pumps were installed just above the transection site. In the right IAN, NGF 300 µg in phosphate buffered saline (PBS) 2 mL was loaded in the pump and pure PBS 2 mL was loaded in the left IAN. The gross clinical finding was evaluated by wound healing, inflammation, implant exposure, and loss of fixture. To evaluate IAN regeneration, electrophysiologic (amplitude, latency, conduction velocity, and peak voltage) and histomorphometric (axon count and density, myelin thickness, and ratio of axon diameter to fiber diameter) analyses were performed. Implant stability quotient, bone-to-implant contact ratio, and new bone area were measured to assess the osseointegration of the NGF-supplying implant. RESULTS: The conduction velocity (2.675 m/second) and peak voltage (1.940 µV) of the NGF group at 6 weeks were considerably higher than those of the PBS group (1.892 m/second and 1.300 µV, respectively). The same results were observed for axon count (NGF vs PBS, 4,576.107 ± 270.413 vs 3,606.972 ± 242.876), axon density (10,707.458 ± 638.835 vs 7,899.781 ± 1,063.625/mm(2)), and myelin thickness (1.670 ± 0.555 vs 1.173 ± 0.388 µm). There were no meaningful differences for the other parameters. CONCLUSIONS: Supplying NGF with specially designed dental implants can be a new therapeutic approach to enable IAN regeneration and osseointegration simultaneously.

Postsurgical Relapse in Class III Patients Treated With Two-Jaw Surgery: Conventional Three-Stage Method Versus Surgery-First Approach.

The aim of this study was to investigate the pattern, amount, and distribution of postsurgical relapse in skeletal Class III patients treated with two-jaw surgery (TJS) using conventional three-stage method (CTM) and surgery-first approach (SFA). A total of 38 patients who underwent the nonextraction approach and TJS (LeFort I posterior impaction and mandibular setback) were divided into CTM and SFA groups (all n = 19/group). Lateral cephalograms were taken before treatment (T0), at 1 month before surgery (T1), immediately after surgery (T2), and at debonding (T3) for CTM patients and at T0, T2, and T3 stages for SFA patients. Cephalometric measurements and statistical analyses were performed. There were no significant differences in the cephalometric variables at all stages except maxillary incisor inclination (U1-UOP) and overbite at T0 between 2 groups. They also did not exhibit significant differences in the amounts of surgical movement except for advancement of the maxilla. The mandible in both groups was rotated slightly clockwise by surgery and counterclockwise during T2-T3 without a significant difference. Distribution of cases with "high relapse" (>30%) and "low relapse" (<30%) of the mandible differed for 2 groups (P < 0.05). SFA group had more "high relapse" cases than CTM group (57.9% versus 26.3%). Postsurgical relapse of the mandible had a positive relationship with the amount of mandibular setback in SFA group (P < 0.01) and clockwise rotation of the proximal segment of the mandible in both groups (P < 0.05 and P < 0.01). The results suggest that SFA might be an effective alternative to CTM if the cause of "high relapse" including amounts of mandibular setback and clockwise rotation of the proximal segment of the mandible during surgery can be controlled.

A novel FGFR2 mutation in tyrosine kinase II domain, L617F, in Crouzon syndrome.

The purposes of this study were to find a novel mutation of FGFR2 in Korean Crouzon syndrome patients and to identify the functional consequences of this mutation. The samples consisted of 16 Crouzon patients. Peripheral venous blood was collected from the patients. FGFR2 mutation screening was performed by direct PCR sequencing of all exons and part of the introns. Restriction fragment length polymorphism (RFLP) analysis was performed to confirm the novel mutation. For functional studies, we performed luciferase assay for Runx2 transcriptional activity, real-time PCR for the bone markers (osteocalcin and alkaline phosphatase), and Western blot for phosphorylated FGFR2 and ERK1/2-MAPK protein. Among 16 patients, 10 showed FGFR2 mutations that had already been reported elsewhere. A novel FGFR2 mutation associated with tyrosine kinase II (TK-II) domain, L617F, was found in one Crouzon syndrome patient by direct PCR sequencing. Presence of this mutation was confirmed using RFLP analysis. Runx2 transcriptional activity and expression of osteocalcin and alkaline phosphatase significantly increased in L617F-transfected cells compared to wild-type cells. FGFR2 autophosphorylation in L617F-transfected cells increased in 1% serum, but ERK1/2-MAPK protein was not activated. The FGFR2-L617F mutation associated with the TK domain is potentially related to premature suture closure in Crouzon syndrome patient.

Clinical outcomes of magnesium-incorporated oxidised implants: a randomised double-blind clinical trial.

OBJECTIVES: This study evaluated implant stability and clinical outcomes obtained with magnesium-incorporated oxidised implants (Mg titanate) and compared them to those blasted magnesium-incorporated oxidised implants (blasted Mg titanate). PATIENTS AND METHODS: Mg titanate was manufactured using the microarc oxidation (MAO) process. To obtain blasted Mg titanate, the MAO process was performed after blasting with TiO2 particles. The 15-month, randomised, double -blind clinical trial was conducted on 54 implants in 40 patients (Mg titanate, 27 implants in 18 subjects; blasted Mg titanate, 27 implants in 22 subjects), in whom 4.0 mm × 10 mm implants were placed to restore the unilateral loss of one or two molars in the mandible. The final prosthesis was attached 3 months postoperatively. Implant stability was measured by the implant stability quotient (ISQ) and periotest value (PTV) at the time of implant insertion, and 2, 3, and 15 months postoperatively. Marginal bone loss was evaluated at 2, 6, and 15 months postoperatively. Soft tissue analysis was performed at 15 months postoperatively. RESULTS: Both implant systems showed high stability at all time points (>71). Mean marginal bone loss was 0.71 ± 0.65 mm and 0.75 ± 0.73 after 15 months in Mg titanate and blasted Mg titanate, respectively. There were no significant differences between the two implant surfaces with respect to ISQ(P = 0.988), PTV(P = 0.935), and marginal bone loss(P = 0.807) after 15 months. CONCLUSION: The success rate after 1 year of follow-up was 100% for both magnesium-incorporated oxidised implants. There were no significant differences in the clinical outcomes between the two surfaces at 15 months follow-up.

Use of cone beam computed tomography in implant dentistry: the International Congress of Oral Implantologists consensus report.

PURPOSE: The International Congress of Oral Implantologists has supported the development of this consensus report involving the use of Cone Beam Computed Tomography (CBCT) in implant dentistry with the intent of providing scientifically based guidance to clinicians regarding its use as an adjunct to traditional imaging modalities. MATERIALS AND METHODS: The literature regarding CBCT and implant dentistry was systematically reviewed. A PubMed search that included studies published between January 1, 2000, and July 31, 2011, was conducted. Oral presentations, in conjunction with these studies, were given by Dr. Erika Benavides, Dr. Scott Ganz, Dr. James Mah, Dr. Myung-Jin Kim, and Dr. David Hatcher at a meeting of the International Congress of Oral Implantologists in Seoul, Korea, on October 6-8, 2011. RESULTS: The studies published could be divided into four main groups: diagnostics, implant planning, surgical guidance, and postimplant evaluation. CONCLUSIONS: The literature supports the use of CBCT in dental implant treatment planning particularly in regards to linear measurements, three-dimensional evaluation of alveolar ridge topography, proximity to vital anatomical structures, and fabrication of surgical guides. Areas such as CBCT-derived bone density measurements, CBCT-aided surgical navigation, and postimplant CBCT artifacts need further research. ICOI RECOMMENDATIONS: All CBCT examinations, as all other radiographic examinations, must be justified on an individualized needs basis. The benefits to the patient for each CBCT scan must outweigh the potential risks. CBCT scans should not be taken without initially obtaining thorough medical and dental histories and performing a comprehensive clinical examination. CBCT should be considered as an imaging alternative in cases where the projected implant receptor or bone augmentation site(s) are suspect, and conventional radiography may not be able to assess the true regional three-dimensional anatomical presentation. The smallest possible field of view should be used, and the entire image volume should be interpreted.

The technique and its role of dacryoendoscopy in the management of the false passage of the lacrimal drainage system.

This is a retrospective study of patients with primary acquired nasolacrimal duct obstruction (PANDO) who underwent dacryoendoscopy (FT-203F; Fibertech Co., Tokyo, Japan) and sheath-guided silicone intubation for 830 cases with PANDO from March 2016 to December 2020. 19 cases (2.3%) were observed as false passage in the lacrimal drainage system (LDS). Dacryoendoscopic findings revealed that the following factors were associated with LDS obstruction (% cases): structural change of 63.2% (stenosis, 42.1%; fibrotic membrane, 21.1%), and secretory change of 36.8% (mucus, 15.8%; stone, 10.5%; and granulation, 10.5%). The obstruction sites were distributed through LDS. The false passages detected in LDS were managed as follow: usage of fluid irrigation pressure to check the true passage following the previously intubated silicone tube as a reference, and confirmation the end of passage through the inferior meatus with nasal endoscopy. The overall success rate was 73.7% using this management technique. Dacryoendoscopy enables real-time observation of the lumen of the LDS, thus facilitating management of pathological lesions including false passages. With this technique, we are better able to make customized treatment of patients with false passages, with a safer and more effective results leading to the success of dacryoendoscopy guided silicone tube intubation in PANDO patients.

Simultaneous loss of TSC1 and DEPDC5 in skeletal and cardiac muscles produces early-onset myopathy and cardiac dysfunction associated with oxidative damage and SQSTM1/p62 accumulation.

By promoting anabolism, MTORC1 is critical for muscle growth and maintenance. However, genetic MTORC1 upregulation promotes muscle aging and produces age-associated myopathy. Whether MTORC1 activation is sufficient to produce myopathy or indirectly promotes it by accelerating tissue aging is elusive. Here we examined the effects of muscular MTORC1 hyperactivation, produced by simultaneous depletion of TSC1 and DEPDC5 (CKM-TD). CKM-TD mice produced myopathy, associated with loss of skeletal muscle mass and force, as well as cardiac failure and bradypnea. These pathologies were manifested at eight weeks of age, leading to a highly penetrant fatality at around twelve weeks of age. Transcriptome analysis indicated that genes mediating proteasomal and macroautophagic/autophagic pathways were highly upregulated in CKM-TD skeletal muscle, in addition to inflammation, oxidative stress, and DNA damage signaling pathways. In CKM-TD muscle, autophagosome levels were increased, and the AMPK and ULK1 pathways were activated; in addition, autophagy induction was not completely blocked in CKM-TD myotubes. Despite the upregulation of autolysosomal markers, CKM-TD myofibers exhibited accumulation of autophagy substrates, such as SQSTM1/p62 and ubiquitinated proteins, suggesting that the autophagic activities were insufficient. Administration of a superoxide scavenger, tempol, normalized most of these molecular pathologies and subsequently restored muscle histology and force generation. However, CKM-TD autophagy alterations were not normalized by rapamycin or tempol, suggesting that they may involve non-canonical targets other than MTORC1. These results collectively indicate that the concomitant muscle deficiency of TSC1 and DEPDC5 can produce early-onset myopathy through accumulation of oxidative stress, which dysregulates myocellular homeostasis.Abbreviations: AMPK: AMP-activated protein kinase; CKM: creatine kinase, M-type; COX: cytochrome oxidase; DEPDC5: DEP domain containing 5, GATOR1 subcomplex subunit; DHE: dihydroethidium; EDL: extensor digitorum longus; EIF4EBP1: eukaryotic translation initiation factor 4E binding protein 1; GAP: GTPase-activating protein; GTN: gastrocnemius; MTORC1: mechanistic target of rapamycin kinase complex 1; PLA: plantaris; QUAD: quadriceps; RPS6KB/S6K: ribosomal protein S6 kinase beta; SDH: succinate dehydrogenase; SOL: soleus; SQSTM1: sequestosome 1; TA: tibialis anterior; TSC1: TSC complex subunit 1; ULK1: unc-51 like autophagy activating kinase 1.

Evaluation of survivin as a prognostic marker in oral squamous cell carcinoma.

BACKGROUND: Poor prognosis of oral squamous cell carcinoma (OSCC) is partly attributed to the lack of significant tumor marker for accurate staging and prognostication. We have evaluated survivin, which is a member of the inhibitor of apoptosis family as a cancer marker associated with proliferation, angiogenesis, oral carcinogenesis, and OSCC patient survival, as we reported a prognostic significance of survivin expression in lymph node previously. METHODS: To evaluate survivin expression in six OSCC cell lines, Western blotting was performed. Hamster oral carcinogenesis model was used to observe changes of survivin expression in oral carcinogenesis. Finally, we assessed the diagnostic and prognostic significance of survivin in a series of 38 primary OSCC through immunohistochemistry (CD31, PCNA) and Kaplan-Meier's test. RESULTS: Survivin expression was detected in all OSCC cell lines at a varying level but not observed in normal gingival keratinocyte cells. In hamster model, survivin expression was observed from 8 weeks through 16 weeks and the intensity of expression became strong until 16 weeks. Clinicopathological analysis revealed a significant correlation between survivin expression and lymph node metastasis (P = 0.006) and proliferation (P < 0.001). However, there was no significant relationship with differentiation, micro vessel density, and cancer stage based on TNM. Survivin overexpression had a significant negative effect on survival of patients. CONCLUSIONS: These results demonstrate the significant relationship between survivin expression and oral carcinogenesis and aggressiveness of OSCC including survival rate of patient. Survivin therefore may be used as a significant cancer marker to gain prognostic information of OSCC.

A comparison of implant stability quotients measured using magnetic resonance frequency analysis from two directions: a prospective clinical study during the initial healing period.

OBJECTIVES: Given that the orientation of the transducer (mesiodistal or buccolingual) affects the data obtained from a piezoelectric resonance frequency analysis (RFA), this study evaluated whether it is necessary to use measurements taken in two different directions (mesiodistal and buccolingual) when using magnetic RFA to assess changes in the stiffness of dental implants. MATERIALS AND METHODS: A prospective clinical trial was completed, in a total of 53 patients, on 71 non-submerged dental implants that were inserted to replace the unilateral loss of mandibular molars. All of the implants were of the same diameter (4.1 mm), length (10 mm), and collar height (2.8 mm). The implant stability quotient (ISQ) was measured during the surgical procedure, and at 4 and 10 weeks after surgery. Measurements were taken twice in each direction: in the buccolingual direction from the buccal side and in the mesiodistal direction from the mesial side. The average of two measurements in each direction was regarded as the representative ISQ of that direction. The higher and lower values of the two ISQs (buccolingual and mesiodistal) were also classified separately. In addition, the variation in ISQ was quantified by subtracting the lower value from the higher value, and the implants were classified into two groups according to this variation: one with ISQ variation of 3 or more and the other with a variation of <3. RESULTS: There were no differences between the two ISQs when measured from different directions, but there were significant differences between the higher and lower values of the ISQs at each measurement point. A significant difference was also observed between the two ISQ variation groups in the pattern of change of the lower value for the period from immediately after surgery to 10 weeks after surgery. CONCLUSION: Acquisition of two directional measurements and classification of the higher and lower values of the two directional ISQs may allow clinicians to detect patterns of change in ISQ that would not be identified if only one directional measurement were made.

A randomized clinical 1-year trial comparing two types of non-submerged dental implants.

OBJECTIVES: This study compared the implant stability and clinical outcomes obtained with two types of non-submerged dental implants that have different thread designs and surface treatments. MATERIALS AND METHODS: A randomized clinical trial with 1 year of follow-up was performed on 56 participants with 75 implants (control group, 36 implants in 28 subjects; experimental group, 39 implants in 28 subjects). The experimental group received the Osstem SSII Implant system; the control group received the Standard Straumann Dental Implant System. The diameter and length of the fixture were uniform at 4.1 mm and 10 mm and all the implants restored the unilateral loss of one or two molars from the mandible. To compare implant stability, the peak insertion torque, implant stability quotient (ISQ), and periotest value (PTV) were evaluated during surgery, and at 4 and 10 weeks after surgery. To compare marginal bone loss, standard periapical radiographs were obtained during surgery, and at 10 weeks and 1 year after surgery. RESULTS: This study showed statistically significant differences between the two groups in peak insertion torque (P=0.009) and ISQ (P=0.003) but not in PTV (P=0.097) at surgery. In contrast, there was no statistically significant difference in the pattern of change of ISQ during the 10 weeks after surgery (P=0.339). For marginal bone loss, no significant difference was observed between the control and the experimental groups before functional loading (P=0.624), but after 1 year of follow-up, a borderline difference was observed (P=0.048). CONCLUSION: The success rate after 1 year of follow-up was 100% for both implant system despite the presence of a significant difference in implant stability during surgery. There was a borderline difference in marginal bone loss after 1 year of follow-up.

Volumetric, planar, and linear analyses of pharyngeal airway change on computed tomography and cephalometry after mandibular setback surgery.

INTRODUCTION: The purpose of this study was to use lateral cephalometry and computed tomography (CT) to examine the volumetric, planar, and linear changes in the pharyngeal airway after mandibular setback surgery. METHODS: The pharyngeal airways of 12 subjects who underwent mandibular setback surgery at Seoul National University Dental Hospital were assessed linearly and volumetrically on lateral cephalometric radiographs and CT before surgery and 6 months after surgery. The pharynx, nasopharynx, and oropharynx were evaluated by volumetric analysis. Pharyngeal depth, airway space, pharyngeal soft-tissue thickness, and hyoid bone position were measured by linear analysis. The axial section area of the airway was measured by area analysis. RESULTS: From the linear analysis, a significant decrease in pharyngeal depth and a significant posterior movement of the hyoid bone (P <0.05) were noted. Volumetric analysis by CT showed that the oropharynx decreased after mandibular setback surgery. However, the volume and the axial section area of the airway in the CT images did not change significantly after mandibular setback surgery (P >0.05). CONCLUSIONS: Although the structures around the mandible inevitably moved backward after mandibular setback surgery on linear analysis, physiologic deformation could occur to preserve the airway capacity after sagittal compression.

Three-dimensional surgical accuracy between virtually planned and actual surgical movements of the maxilla in two-jaw orthognathic surgery.

OBJECTIVE: To investigate the three-dimensional (3D) surgical accuracy between virtually planned and actual surgical movements (SM) of the maxilla in twojaw orthognathic surgery. METHODS: The sample consisted of 15 skeletal Class III patients who underwent two-jaw orthognathic surgery performed by a single surgeon using a virtual surgical simulation (VSS) software. The 3D cone-beam computed tomography (CBCT) images were obtained before (T0) and after surgery (T1). After merging the dental cast image onto the T0 CBCT image, VSS was performed. SM were classified into midline correction (anterior and posterior), advancement, setback, anterior elongation, and impaction (total and posterior). The landmarks were the midpoint between the central incisors, the mesiobuccal cusp tip (MBCT) of both first molars, and the midpoint of the two MBCTs. The amount and direction of SM by VSS and actual surgery were measured using 3D coordinates of the landmarks. Discrepancies less than 1 mm between VSS and T1 landmarks indicated a precise outcome. The surgical achievement percentage (SAP, [amount of movement in actual surgery/ amount of movement in VSS] × 100) (%) and precision percentage (PP, [number of patients with precise outcome/number of total patients] × 100) (%) were compared among SM types using Fisher's exact and Kruskal-Wallis tests. RESULTS: Overall mean discrepancy between VSS and actual surgery, SAP, and PP were 0.13 mm, 89.9%, and 68.3%, respectively. There was no significant difference in the SAP and PP values among the seven SM types (all p > 0.05). CONCLUSIONS: VSS could be considered as an effective tool for increasing surgical accuracy.

Treatment modalities for Korean patients with unilateral hemifacial microsomia according to Pruzansky-Kaban types and growth stages.

OBJECTIVE: To investigate the treatment modalities (Tx-Mods) for patients with unilateral hemifacial microsomia (UHFM) according to Pruzansky-Kaban types and growth stages. METHODS: The samples consisted of 82 Korean UHFM patients. Tx-Mods were defined as follows: Tx-Mod-1, growth observation due to mild facial asymmetry; Tx-Mod-2, unilateral functional appliance; Tx- Mod-3, fixed orthodontic treatment; Tx-Mod-4, growth observation due to a definite need for surgical intervention; Tx-Mod-5, unilateral mandibular or bimaxillary distraction osteogenesis (DO); Tx-Mod-6, maxillary fixation using LeFort I osteotomy and mandibular DO/sagittal split ramus osteotomy; Tx- Mod-7, orthognathic surgery; and Tx-Mod-8, costochondral grafting. The type and frequency of Tx-Mod, the number of patients who underwent surgical procedures, and the number of surgeries that each patient underwent, were investigated. RESULTS: The degree of invasiveness and complexity of Tx-Mod increased, with an increase in treatment stage and Pruzansky-Kaban type (initial < final; [I, IIa] < [IIb, III], all p < 0.001). The percentage of patients who underwent surgical procedures increased up to 4.2 times, with an increase in the Pruzansky-Kaban type (I, 24.1%; IIa, 47.1%; IIb, 84.4%; III, 100%; p < 0.001). However, the mean number of surgical procedures that each patient underwent showed a tendency of increase according to the Pruzansky-Kaban types (I, n = 1.1; IIa, n = 1.5; IIb, n = 1.6; III, n = 2.3; p > 0.05). CONCLUSIONS: These findings might be used as basic guidelines for successful treatment planning and prognosis prediction in UHFM patients.

Distribution and phenotypes of hemifacial microsomia and its association with other anomalies.

OBJECTIVE: To investigate the distribution and phenotypes of hemifacial microsomia (HFM) and its association with other anomalies. METHODS: This study included 249 Korean patients with HFM, whose charts, photographs, radiographs, and/or computed tomography scans acquired during 1998-2018 were available from Seoul National University Hospital and Dental Hospital. Prevalence according to sex, side involvement, degree of mandibular deformity, compensatory growth of the mandibular body, and Angle's classification, and its association with other anomalies were statistically analyzed. RESULTS: Prevalence was not different between male and female patients (55.0% vs. 45.0%, p > 0.05). Unilateral HFM (UHFM) was more prevalent than bilateral HFM (BHFM) (86.3% vs. 13.7%, p < 0.001). Although distribution of the Pruzansky-Kaban types differed significantly in patients with UHFM (I, 53.0%; IIa, 18.6%; IIb, 24.7%; III, 3.7%; p < 0.001), no difference was observed in occurrence between the right and left sides (52.6% vs. 47.4%, p > 0.05). Among patients with BHFM, prevalence of different Pruzansky-Kaban types on the right and left sides was greater than that of the same type on both sides (67.6% vs. 32.4%, p < 0.05). Despite hypoplasia of the condyle/ramus complex, compensatory growth of the mandibular body on the ipsilateral side occurred in 35 patients (14.1%). Class I and II molar relationships were more prevalent than Class III molar relationships (93.2% vs. 6.8%, p < 0.001). Forty-eight patients (19.3%) had other anomalies, with 50.0% and 14.4% in the BHFM and UHFM groups (p < 0.001). CONCLUSIONS: Patients with HFM require individualized diagnosis and treatment planning because of diverse phenotypes and associations with other anomalies.

Trifocal distraction-compression osteosynthesis in conjunction with passive self-ligating brackets for the reconstruction of a large bony defect and multiple missing teeth.

Reconstruction of a maxillary dentoalveolar defect and closure of a wide oronasal fistula in a patient with a traumatic injury are challenging for both orthodontists and surgeons. A conventional bone graft is used to fill the alveolar bone defect, to restore continuity between bony segments, and to provide bony support for tooth eruption adjacent to the defect or for orthodontic tooth movement into the bony defect. However, if the defect is too large to allow for a conventional bone graft, transport distraction osteogenesis can be used for reconstruction of the alveolar bone and implant placement. However, there is usually a discrepancy in the movement rates between the bony segment and the teeth. Passive self-ligating brackets can minimize friction between the bracket and the archwire; therefore, the rate of tooth movement can be balanced with that of the bony segment. By using orthodontic miniscrew and elastomeric traction, the regenerated bony segments can be bent to form a curved arch in the alveolar bone. In the treatment reported here, trifocal distraction-compression osteosynthesis with orthodontic miniscrews and passive self-ligating brackets helped establish bone continuity in a bony defect area, created anterior curvature of the alveolar bone, and provided good-quality regenerated bone for implant placement.

Condyle as the point of rotation for 3-D planning of distraction osteogenesis for hemifacial microsomia.

AIM: The purpose of this study is to present an exact simulation method for mandibular rotational movement in distraction osteogenesis for hemifacial microsomia. METHODS: Three-dimensional (3-D) surgery simulation software programmes (V-Works and V-Surgery; Cybermed, Seoul, Korea) were used, based on 3-D CT data in addition to the conventional data, which included facial photography, panoramic radiograph, cephalogram, and dental models. After measuring the mandibular deficiency (horizontal and vertical) from a 3-D model reconstructed using the software, the angulation of the distraction device to the mandibular border (posterior or inferior) was determined. The rotation axis in the V-Works simulation was defined as the line perpendicular to the plane made by condylion and the distraction vector location on the mandible. The mandible moves along the plane around this rotational axis during distraction. After the 3-D simulation with the software programme, mock surgery on a rapid prototyping model was performed. This planning method was applied to models of two hemifacial microsomia patients. RESULTS: With this protocol, it was possible to simulate the rotational movement of the mandible on the axis passing through the condylar head of the unaffected side. CONCLUSION: The sequential planning procedure presented in this paper is considered to be helpful in performing effective preoperative simulation of distraction osteogenesis for hemifacial microsomia.