Catch-Up Growth Pattern in Cleft Palate: A Longitudinal Study from Infancy to Adolescence.

OBJECTIVE: To characterize the patterns of somatic catch-up growth from infancy to adolescence in patients with cleft palate (CP). STUDY DESIGN: We assessed 474 nonsyndromic patients with isolated cleft palate (n = 69) and unilateral and bilateral cleft lip and palate (n = 271; n = 134) who underwent palatoplasty between 1988 and 2017 and had longitudinal physical growth data at birth (T0), cheiloplasty (T1), palatoplasty (T2), childhood (T3), and adolescence (T4). The z scores of weight (ZWT), height (ZHT), and body mass index (ZBMI) were compared among the CP types (isolated cleft palate, unilateral cleft lip and palate, and bilateral cleft lip and palate) and time points (T1, T2, T3, and T4). Subgroup analyses were performed to investigate the growth of patients with malnourishment (z score < -1) at T1 or T2. A generalized linear model was used to investigate the effects of gestational age and cardiac anomalies on the longitudinal changes in ZHT and ZBMI. RESULTS: Regardless of the time point, the overall ZHT, ZWT, and ZBMI approximated 0 in all CP types, indicating few differences from the mean values of noncleft children. Significant catch-up growth occurred in ZHT and ZWT from T1 to T4 for all CP types (all P < .05). Despite the recovery of ZHT and ZBMI in most patients with malnourishment, these values remain relatively low until adolescence. Patients who were born at preterm stage or had surgically repaired cardiac anomalies grew well. CONCLUSIONS: Even in infants with CP and malnutrition, preterm birth, or cardiac anomalies, rapid catch-up growth can occur prior to palatoplasty with the help of comprehensive cleft care.

Classification of Skeletal Phenotypes of Preadolescent Patients With Isolated Cleft Palate Using Principal Component Analysis and Cluster Analysis.

This study aimed to classify the skeletal phenotypes of preadolescent patients with isolated cleft palate using principal component analysis and cluster analysis. Sixty-four preadolescent female patients with isolated cleft palate (incomplete hard palate and complete soft palate cleft group, n=51; complete cleft of the hard and soft palate group, n=13; the mean age when lateral cephalograms were taken, 7.08±0.76 y) were included. Ten angular and 2 ratio cephalometric variables were measured on a lateral cephalogram. Cluster analysis was performed using 3 representative variables obtained from principal component analysis (SN-GoMe, SNA, and SNB). The differences in the variables among the clusters were characterized using the Kruskal-Wallis test. As a result of the analysis, 6 clusters were obtained from 3 groups: the retrusive maxilla and mandible group: cluster 3 (14.1%, moderately hyperdivergent pattern), cluster 5 (17.2%, severely hyperdivergent pattern); the normal maxilla and mandible group: cluster 1 (23.4%, normodivergent pattern), cluster 4 (12.5%, moderately hyperdivergent pattern), cluster 6 (20.3%, severely hyperdivergent pattern); the normal maxilla and protrusive mandible group: cluster 2 (12.5%, normodivergent pattern). The distribution of isolated cleft palate types did not differ among the 6 clusters ( P >0.05). Two thirds of the patients (68.7%, clusters 1, 2, 4, and 6) had a normal anteroposterior position of the maxilla, while one third of the patients (31.3%, clusters 3 and 5) showed a retrusive mandible. These results indicate that isolated cleft palate patients have diverse maxillo-mandibular growth patterns compared with patients with cleft lip and palate.

Distribution and Phenotype of Goldenhar Syndrome and Its Association With Other Anomalies.

The purpose of this study was to investigate the distribution and phenotype of Goldenhar syndrome (GS) and its association with other anomalies. The samples consisted of 18 GS patients (6 males and 12 females; mean age at investigation, 7.4 ± 4.8 y) who were treated or followed up at the Department of Orthodontics, Seoul National University Dental Hospital between 1999 and 2021. The prevalence of side involvement and degree of mandibular deformity (MD), midface anomalies, and association with other anomalies were evaluated using statistical analysis. The prevalence of unilateral and bilateral MD did not differ (55.6% versus 44.4%). In unilateral MD cases, there was a tendency for higher prevalence of more severe Pruzansky-Kaban types than mild ones (type I, 10%; type IIa, 10%; type IIb, 50%; type III, 30%). Despite hypoplasia of the condyle/ramus complex, compensatory mandibular body growth occurred in 33.3% of GS patients (more severe side in bilateral MD cases, 37.5%, and ipsilateral side in unilateral MD cases, 30%). Class II molar relation was more prevalent than class I and class III molar relations (72.2% versus 11.1% versus 16.7%, P <0.01). Al total of 38.9% of patients had congenitally missing tooth. #7 facial cleft was found in 44.4% of patients. In midface anomalies, ear problem was the most common anomaly, followed by hypoplasia/absence of zygomatic arch and eye problem (88.9% versus 64.3% versus 61.1%, P <0.01). Association with the midface, spine, cardiovascular, and limb anomalies did not differ between unilateral and bilateral MD cases. These results might provide a basic guideline for diagnosis and treatment planning for GS patients.

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.

Characterization of Treatment Modalities for Patients With Syndromic Craniosynostosis in Relation to Degree of Midface Hypoplasia and Patient's Age Using Longitudinal Follow-Up Data.

ABSTRACT: The purpose of this study was to investigate the type and frequency of use of treatment modalities (Tx-Mods) in patients with syndromic craniosynostosis (SC) using longitudinal follow-up data. A total of 28 patients with SC (24 Crouzon, 2 Apert, and 2 Antley-Bixler syndromes), who were treated at the Department of Orthodontics, Seoul National University Dental Hospital, Seoul, South Korea between 1998 and 2020, was included. According to the degree of midface hypoplasia (MH) at the initial visit (T1), the patients were divided into the mild-MH (78°≤SNA < 80°, n = 8), moderate-MH (76≤SNA < 78°, n = 7), and severe-MH (SNA < 76°, n = 13) groups. T1-age and Tx-Mods, including cal-varial surgery (CALS), orthopedic treatment (OPT), fixed orthodontic treatment, and midface advancement surgery in childhood (MAS-child) and adulthood (MAS-adult), were investigated. Complexity of MAS-adult was graded as follows: 0, no surgery; 1, orthognathic surgery; 2, distraction osteogenesis (DOG); 3, combination of distraction osteogenesis and orthognathic surgery. Then, statistical analysis was performed. Percentage distribution of Tx-Mods was 71.4% in CALS, 21.4% in MAS-child, 42.9% in OPT, 100% in fixed orthodontic treatment, and 89.3% in MAS-adult. 92.9% of patients underwent MAS more than once. The number of MAS increased according to the severity of MH ( P < 0.05). The complexity of MAS-adult increased as T1-age and severity of MH increased (all P < 0.05); whereas it decreased when CALS and OPT were performed (all P < 0.05). However, MAS in childhood did not guarantee the avoidance of additional MAS in adulthood ( P > 0.05). These findings may be used as basic guidelines for successful treatment planning and prognosis prediction in patients with SC.

Early Prediction of the Need for Orthognathic Surgery in Patients With Repaired Unilateral Cleft Lip and Palate Using Machine Learning and Longitudinal Lateral Cephalometric Analysis Data.

ABSTRACT: The purpose of this study was to determine the cephalometric predictors of the future need for orthognathic surgery in patients with repaired unilateral cleft lip and palate (UCLP) using machine learning. This study included 56 Korean patients with UCLP, who were treated by a single surgeon and a single orthodontist with the same treatment protocol. Lateral cephalograms were obtained before the commencement of orthodontic/orthopedic treatment (T0; mean age, 6.3 years) and at at least of 15 years of age (T1; mean age, 16.7 years). 38 cephalometric variables were measured. At T1 stage, 3 cephalometric criteria (ANB ≤ -3°; Wits appraisal ≤ -5 mm; Harvold unit difference ≥34 mm for surgery group) were used to classify the subjects into the surgery group (n = 10, 17.9%) and non-surgery group (n = 46, 82.1%). Independent t-test was used for statistical analyses. The Boruta method and XGBoost algorithm were used to determine the cephalometric variables for the prediction model. At T0 stage, 2 variables exhibited a significant intergroup difference (ANB and facial convexity angle [FCA], all P < 0.05). However, 18 cephalometric variables at the T1 stage and 14 variables in the amount of change (ΔT1-T0) exhibited significant intergroup differences (all, more significant than P < 0.05). At T0 stage, the ANB, PP-FH, combination factor, and FCA were selected as predictive parameters with a cross-validation accuracy of 87.4%. It was possible to predict the future need for surgery to correct sagittal skeletal discrepancy in UCLP patients at the age of 6 years.

Characterization of phenotypes and predominant skeletodental patterns in pre-adolescent patients with Pierre-Robin sequence.

OBJECTIVE: To investigate the phenotypes and predominant skeletodental pattern in pre-adolescent patients with Pierre-Robin sequence (PRS). METHODS: The samples consisted of 26 Korean pre-adolescent PRS patients (11 boys and 15 girls; mean age at the investigation, 9.20 years) treated at the Department of Orthodontics, Seoul National University Dental Hospital between 1998 and 2019. Dental phenotypes, oral manifestation, cephalometric variables, and associated anomalies were investigated and statistically analyzed. RESULTS: Congenitally missing teeth (CMT) were found in 34.6% of the patients (n = 9/26, 20 teeth, 2.22 teeth per patient) with 55.5% (n = 5/9) exhibiting bilaterally symmetric missing pattern. The mandibular incisors were the most common CMT (n = 11/20). Predominant skeletodental patterns included Class II relationship (57.7%), posteriorly positioned maxilla (76.9%) and mandible (92.3%), hyper-divergent pattern (92.3%), high gonial angle (65.4%), small mandibular body length to anterior cranial base ratio (65.4%), linguoversion of the maxillary incisors (76.9%), and linguoversion of the mandibular incisors (80.8%). Incomplete cleft palate (CP) of hard palate with complete CP of soft palate (61.5%) was the most frequently observed, followed by complete CP of hard and soft palate (19.2%) and CP of soft palate (19.2%) (p < 0.05). However, CP severity did not show a significant correlation with any cephalometric variables except incisor mandibular plane angle (p < 0.05). Five craniofacial and 15 extra-craniofacial anomalies were observed (53.8% patients); this implicated the need of routine screening. CONCLUSIONS: The results might provide primary data for individualized diagnosis and treatment planning for pre-adolescent PRS patients despite a single institution-based data.

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.

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, side involvement, phenotype and associated anomalies of Korean patients with craniofacial clefts from single university hospitalbased data obtained during 1998-2018.

OBJECTIVE: To investigate the distribution, side involvement, phenotype, and associated anomalies of Korean patients with craniofacial clefts (CFC). METHODS: The samples consisted of 38 CFC patients, who were treated at Seoul National University Dental Hospital during 1998-2018. The Tessier cleft type, sex, side involvement, phenotype, and associated anomalies were investigated using nonparametric statistical analysis. RESULTS: The three most common types were #7 cleft, followed by #0 cleft and #14 cleft. There was no difference between the frequency of male and female. Patients with #0 cleft exhibited nasal deformity, bony defect, and missing teeth in the premaxilla, midline cleft lip, and eye problems. A patient with #3 cleft (unilateral type) exhibited bilateral cleft lip and alveolus. All patients with #4 cleft were the bilateral type, including a combination of #3 and #4 clefts, and had multiple missing teeth. A patient with #5 cleft (unilateral type) had a posterior openbite. In patients with #7 cleft, the unilateral type was more prevalent than the bilateral type (87.0% vs. 13.0%, p < 0.001). Sixteen patients showed hemifacial microsomia (HFM), Goldenhar syndrome, and unilateral cleft lip and palate (UCLP). There was a significant match in the side involvement of #7 cleft and HFM (87.5%, p < 0.01). Patients with #14 cleft had plagiocephaly, UCLP, or hyperterorbitism. A patient with #30 cleft exhibited tongue tie and missing tooth. CONCLUSIONS: Due to the diverse associated craniofacial anomalies in patients with CFC, a multidisciplinary approach involving a well-experienced cooperative team is mandatory for these patients.

Hyaluronic acid-cross-linked filler stimulates collagen type 1 and elastic fiber synthesis in skin through the TGF-ß/Smad signaling pathway in a nude mouse model.

Compared to pure hyaluronic acid filler, cross-linked hyaluronic acid (HAc) exhibits superior biocompatibility and longevity as a dermal filler. We previously developed composite HAc-hydroxyapatite (HAp) fillers. Herein, we systematically compared the protein-level increase and gene expression between HAc-micro-HAp and HAc-nano-HAp in mice and determined the mechanisms underlying the biological responses to HAc and HAp. Five-week-old female BALB/c-nude mice were classified into five groups: normal skin, Radiesse, Restylane, HAc-nano-HAp, and HAc-micro-HAp. Fillers (200 µl) were injected to evenly fill the back of mice. Skin biopsies were performed to investigate collagen and elastic fiber synthesis after filler injections. Western blot analysis, real-time polymerase chain reaction analysis, and immunohistochemistry were performed to investigate protein and gene expression changes. Organ (liver, lung, spleen, and kidney) toxicity of HAc-nano-HAp was determined by hematoxylin and eosin staining after 12 weeks. Protein and gene expression analyses indicated that, compared with pure fillers, HAc-nano-HAp and HAc-micro-HAp hydrogels preferentially promoted collagen and elastic fiber formation through the TGF-ß pathway. The composite fillers also exhibited no evidence of organ toxicity. HAc-HAp filler might play an important role in collagen and elastic fiber regeneration. HAc filler stimulates collagen type 1 and elastic fiber synthesis through the TGF-ß/Smad pathway. The role of HAc-HAp composite fillers in photoaging in animal models and their effects on skin, including elasticity and tensile strength, should be investigated.

Orthodontic and orthopedic treatment for a growing patient with Tessier number 0 cleft.

The purpose of this case report was to introduce the concept of orthodontic and orthopedic treatment for a growing patient with Tessier number 0 cleft. A 5-year-old boy patient with Tessier number 0 cleft presented congenitally missing maxillary central incisors (MXCI), a bony defect at the premaxilla, a constricted maxillary arch, an anterior openbite, and maxillary hypoplasia. His treatment was divided into three stages: management of the bony defect at the premaxilla and the congenitally missing MXCIs using a fan-type expansion plate, iliac bone grafting, and eruption guidance of the maxillary lateral incisors into the graft area for substitution of MXCIs; management of the maxillary hypoplasia using sequential facemask therapy with conventional and skeletal anchorage; and management of the remaining occlusal problems using fixed orthodontic treatment. The total treatment duration was 15 years and 10 months. Class I canine and Class II molar relationships and normal overbite and overjet were achieved at the end of treatment. Although the long-term use of facemask therapy resulted in significant protraction of the retrusive maxilla, the patient exhibited Class III profile because of continued mandibular growth. However, the treatment result was well maintained after 2 years of retention. The findings from this case suggest that interdisciplinary and customized approaches are mandatory for successful management of maxillary hypoplasia, bony defect, and dental problems in Tessier number 0 cleft. Moreover, considering the potential of orthognathic surgery or distraction osteogenesis, meticulous monitoring of mandibular growth until growth completion is important.

Staged lower lip reconstruction following gangrenous stomatitis in an immunosuppressed patient.

A 70-year-old male with a history of diabetes mellitus, hypertension, and coronary stent insertion visited our hospital 7 days after biting his lower lip. Swelling and inflammation had worsened despite debridement and antibiotic treatment. On the 8th hospital day, fungal infection with Candida albicans and superimposed bacterial infection with Klebsiella pneumoniae were found on tissue culture. Extensive necrosis resulted in a defect of approximately 3/4 of the entire lower lip and a full-layer skin defect from the vermilion to the gingivobuccal sulcus at the right corner of the mouth. To correct drooling, incomplete lip sealing, and trismus, staged reconstruction was performed with consideration of cosmetic and functional features. The treatment process using staged reconstruction and antifungal treatment for an extensive lower lip defect caused by fungal stomatitis is described.

Malar Relocation with Reverse-L Osteotomy and Autogenous Bone Graft.

The zygomaticomaxillary complex (ZMC) functions as a buttress for the face and is the cornerstone to a person's aesthetic appearance, by both setting the midfacial width and providing prominence to the cheek. Malar deficiency is often acquired by blunt injury incurred in a traumatic accident, resulting in ZMC fracture. A 48-year-old male patient presented a right ZMC fracture after contusion injury by a baseball. He only received conservative management and later he suffered discomfort during mouth opening at the moment of mastication, due to trismus involving the temporomandibular joint. In the current case, we describe a surgical technique, by which the malar body is shifted anteriorly and laterally after combined oblique-vertical osteotomy. The technique presented, eventually restored the former aesthetic position of the malar complex and symmetry, and, moreover, improved mastication function.

The use of botulinum toxin type A in aesthetic mandibular contouring.

The lower third of Asian faces is wider than that of Caucasians and it is determined by the size and width of the mandibular bone and the thickness of muscles and subcutaneous fat tissues surrounding it. Efforts to create an aesthetically slim and smooth facial contour line in nonobese people have led the authors to focus on two approaches: surgical resection of the masseteric muscle and modeling ostectomy of the square-angled mandibular bone. Because these procedures present some problems, the authors adopted a nonsurgical concept that chemically denervates muscles and reduces the bulk of the muscle. The authors have conducted a total of 1021 clinical cases from March of 2001 through September of 2002, in which patients were treated with botulinum toxin type A (Dysport; Ipsen Ltd, Slough, United Kingdom) for remodeling the lower facial contour line; 383 of those cases were followed up for at least 3 months after the initial injection. A database was made by measuring the change in the thickness of the injected muscle with an ultrasonogram. Eleven patients underwent resection of the mandibular angle before injection. The preinjection ostectomy group was involved in the study as a result of their dissatisfaction with the surgical results; they had a rather thick masseter muscle and not a bone problem. Some had both bone problems and a thick masseter muscle. Three months after the botulinum toxin injection, the thickness of the muscle was reduced by 31 percent on average. The atrophic effect of injection was observed after 2 to 4 weeks for most patients. Seventy percent of the 383 patients tracked were greatly satisfied with the result, with another 23 percent generally satisfied. No long-term side effects were reported. Masseteric hypertrophy is frequent in Asians because of racial characteristics and dietary habits. Botulinum toxin type A has made a new epoch in facial contouring for Asians. Considering that Asians have a prominent malar and a prominent mandible angle, the reduction in the thickness of the masseter can provoke relative prominence of the malar and mandible angle. Therefore, precise indication and anatomy of the facial muscle should be thoroughly understood, which will decrease the incidence of side effects and problems. Botulinum toxin type A (Dysport) injection is simple in technique, has few side effects, and promises a rapid return to daily life. The authors conclude that the injection of botulinum toxin type A can replace surgical masseter resection.