Treatment Strategy for Condyle/Ramus Deficiency Using 3D Virtual Surgery and CAD/CAM Technologies; Total Joint Replacement or Inverted-L Osteotomy.

OBJECTIVE: To introduce a guideline for selecting proper surgical modalities for correction of skeletal Class II malocclusion with moderate-to-severe vertical height deficiency (VHD) of the condyle/ramus complex (CRC) using bimaxillary surgery in conjunction with total joint replacement (TJR) or inverted-L osteotomy (ILO) assisted by 3D virtual surgical planning and CAD/CAM technologies. CASES: Four cases of severe skeletal Class II patients with moderate-to-severe VHD of CRC were presented. They underwent bimaxillary surgery using Le Fort I osteotomy in the maxilla and TJR or ILO in the mandible, with the help of virtual surgical planning (VSP) and computer-aided design/computer-aided manufacturing (CAD/CAM)-printed surgical guides and osteosynthesis plates. Guidelines are as follows: (1) if a patient has a moderate degree of VHD and the function of the temporomandibular joint (TMJ) is normal, ILO would be preferred for vertical elongation of the ramus; (2) if a patient has congenitally small condyle or severe condylar resorption, TJR would be preferred to resolve severe VHD of CRC; and (3) when a patient has a metal allergy, foreign body reaction or anatomic limitations (ie, thin cranial base cortex for fossa fixation), ILO would be a better option than TJR. RESULTS: TJR or ILO using VSP and CAD/CAM-printed surgical guides, wafers, and customized plates can provide a proper selection of the surgical plan, accurate transfer of surgical plans to actual surgical procedures, and esthetic improvement of the facial profile. CONCLUSION: This guideline based on the degree of VHD and functional aspects of CRC might help clinicians to select effective surgical modality for correction of skeletal Class II malocclusion with moderate-to-severe VHD of CRC.

Classifications of Prominent Mandibular Angle and Surgical Considerations for Mandibuloplasty.

Contouring surgery is an operation that makes a smooth, oval-shaped face by removing protruding parts of the face. In particular, mandibuloplasty is a procedure that softens the shape of the mandible and is a popular procedure among Asians with a dominant mesocephalic profile. In this study, we tried to discuss the considerations before surgery by dividing the mandibular shape into morphologic aspects in the lateral and frontal views and anatomic considerations. In the lateral view, it is essential to consider the posterior ramal height and mandibular body length of each patient. These factors are closely related to the postoperative outcomes. Consideration of the mandibular plane angle is also essential. In the frontal view, the position of the gonial angle relative to the ramal body should be considered because the position of the gonial angle can affect the difficulty of operation. Anatomic considerations include antero-posterior ramal width, bucco-lingual width of mandibular body, amount of mouth opening, and location of inferior alveolar nerve. These are important factors that determine the difficulty of the operation. In this study, classification according to the shape and shape of the mandible was presented, and considerations for each classification were discussed. Cosmetic surgery is a socio-psychologically meaningful procedure that not only improves the esthetics but also improves the mental well-being of the patients. Therefore, it will be possible to provide better medical services to patients if clinicians are fully aware of the factors that can increase the difficulty of the operation and the factors that affect the surgical outcome.

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.

Surgical Accuracy of 3D Virtual Surgery and CAD/CAM-Assisted Orthognathic Surgery for Skeletal Class III Patients.

Orthognathic surgery is an effective surgical method to achieve functionality and facial esthetics for mandibular prognathism. If surgery is performed with a conventional method, errors may occur in the surgical preparation process and the surgical procedures, and there is a limitation in that the accuracy of surgery is determined according to the surgeon's experience and tactual sense. However, with the recent development of three-dimensional (3D) virtual planning and CAD/CAM technology, more 3D and predictable surgical planning and more accurate and time-saving surgery have become possible. The purpose of this study is to evaluate the surgical accuracy of 3D Virtual Surgery, CAD/CAM-Assisted Orthognathic surgery for Skeletal Class III Patients. The study included 18 patients who had undergone orthognathic surgery for skeletal class III malocclusion from January 2020 to December 2021. To evaluate the accuracy of the virtual planning, 3D facial cone-beam computed tomography taken immediately after surgery (T1) and virtual surgery data (Tv) were superimposed in each patient. Landmarks were set on each of the maxillary segment, mandibular distal segment, and left and right mandibular proximal segment, and the difference between T1 and Tv was compared 3D on the x , y , and z -axis. (ΔT: T1-Tv). As a result, the average distance between Tv and T1 at each landmark, all landmarks except for the posterior nasal spine of the maxillary segment showed <1 mm. In particular, the differences across the x and z -axis were very small, while the difference across the y -axis tend to be large. The comparison of the position of each segment in virtual surgery and actual surgery was as follows. It can be seen that all segments were located slightly downward, and the medial pole of the mandibular proximal segment was located posterolateral and the lateral pole was located anteromedial after the actual surgery compared with the virtual planning. It means that the proximal segment was slightly rotated, but the difference was within 1 mm, so it can be considered that the surgery was accurate. Base on this study, orthognathic surgery using 3D virtual surgery planning and CAD/CAM technologies was very accurate. By applying these cutting-edge technologies to clinical practice, it was possible not only to increase the predictability of surgery but also to improve the convenience of surgery. Therefore, it is thought that it will be important for clinicians to make continuous efforts to applicate cutting-edge technologies to be developed in the future to patient diagnosis and surgery.

The Efficacy of 3D Virtual Surgery, CAD/CAM, and 3D Printing Technology for Maxillomandibular Advancement in Obstructive Sleep Apnea Patients.

OBJECTIVE: Maxillomandibular advancement (MMA) is the most effective surgical method for treating obstructive sleep apnea, and it moves the maxillomandibular complex forward to increase the entire upper airway volume. By using 3-dimensional (D) virtual surgery, computer-aided design/computer-aided manufacturing, and 3D printing technologies, it is possible to overcome all the limitations of conventional methods. MATERIALS AND METHODS: In this study, (modified) MMA was performed by applying 3D technologies to obstructive sleep apnea patients. Virtual surgery was done as surgical plan, cutting guides, and customized plates were made by computer-aided design/computer-aided manufacturing and 3D printing technologies for surgical procedures. RESULTS: After surgery, all patients improved their appearance, quality of sleep, and sleep apnea level were dramatically improved. Through these results, it was found that there are many advantages in using 3D technologies for preparing and implementing MMA. CONCLUSIONS: It was confirmed that the accuracy and efficiency of surgery were increased by applying 3D technologies. This suggests that 3D technologies are very useful tools in surgical area.

Causes of Reoperation Consultation and Clinical Review of Actual Reoperation After Previous Orthognathic Surgery.

OBJECTIVE: To investigate the causes of reoperation consultation, and the actual percentage and procedures of reoperation after previous orthognathic surgery. METHODS: The samples consisted of 30 patients who visited our clinic for reoperation consultation from October 2015 to September 2021 (6 males and 24 females; mean age at reoperation consultation, 28.4 y). Patient's causes of reoperation consultation were divided into "esthetic dissatisfaction," "airway changes," "temporomandibular disorders," "uncomfortable occlusion," and "other complications". In terms of esthetic dissatisfaction, the more detailed esthetic problem was evaluated by the clinical chart, facial photographs, and radiographs. In patients who actually underwent reoperation, the actual percentage and procedures of reoperation were investigated. RESULTS: The most prevalent causes for reoperation consultation were "esthetic dissatisfaction" (n = 21, 70.0%), followed by "airway changes" (n = 11, 36.7%), "uncomfortable occlusion" (n = 8, 26.7%), "other complications" (n = 5, 16.7%), and "temporomandibular disorder" (n = 4, 13.3%). Less than half of patients actually underwent reoperation (n = 13, 43.3%). Actual reoperation procedures included minor revision surgery, reconstruction surgery, or complete reoperation according to the patient's need. In case of complete reoperation, more accurate and predictable results were obtained by using virtual surgical planning, customized surgical guides, titanium surgical plates made with computer-aided design and computer-aided manufacturing technique, and a 3-dimensional printing method. CONCLUSION: It is important to communicate with patients about expectations for facial esthetic improvement by orthognathic surgery for obtaining the patient's postoperative satisfaction.

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.

The Accuracy and Stability of Intentional Change of Frontal-Ramal Inclination in Orthognathic Surgery for Facial Asymmetry Patients.

Facial asymmetry can be defined as differences in the left and right sides of the face, and most of the patients with facial asymmetry have different left and right frontal-ramal inclinations (FRIs). Restoring the symmetry of both FRIs is important in the surgery of facial asymmetry patients, but it is very difficult to achieve perfect symmetry through conventional orthognathic surgery. However, by using 3-dimensional (3D) virtual planning and CAD/CAM technolo gies, intentional change of FRIs can be possible so the symmetry can be improved. The purpose of this study is to evaluate the surgical accuracy and long-term stability of intentional change of FRIs by 3D virtual surgery, CAD/CAM-assisted orthognathic surgery for patients with facial asymmetry. The study included 20 patients who had undergone orthognathic surgery for skeletal class III malocclusion from January 2019 to December 2021. To evaluate the accuracy of surgery, 3D facial cone beam computed tomography (CBCT) taken immediately after surgery (T1) and virtual surgery data (Tv) were measured and the difference values were calculated. The evaluation of the long-term stability of intentional change of FRI was performed by measuring T1 and T2 (3D facial cone beam computed tomography images taken 6 mo after surgery) and the difference values were calculated. The difference values of FRIs in the left and right proximal segments of each patient were calculated. And then, for comparison depending on the direction of rotation, increased FRI groups (n=20, medial rotation) and decreased FRI groups (n=20, lateral rotation) were analyzed separately. As a result, all difference values at both (ΔT1-Tv) and (ΔT2-T1) were <1 degree. As a result of analyzing the entire FRI by dividing it into decreasing and increasing groups, the mean value of (ΔT1-Tv) was 0.225 degrees for the decreasing group and 0.275 degrees for the increasing group. It means that the proximal segment moved less than the movement implemented by the virtual surgery through actual surgery but it shows a very small error, which means that the overall operation almost accurately implements the virtual surgical planning. Compared with (ΔT1-Tv), the mean value of (ΔT2-T1) showed a much smaller error value, and no specific tendency was observed. This indicates that the stability after surgery is very good. Based on this study, using 3D virtual surgery planning and CAD/CAM technologies for treating patients with facial asymmetry was very useful, and surgery could be performed accurately and predictably. In particular, left-right symmetry was almost perfectly achieved through virtual simulation and could be implemented through actual surgery. Therefore, it can be said that the use of these 3D technologies is recommended for the surgical approach of facial asymmetry.

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.

Restoration of Facial Bone Defect using Patient-Specific Implant.

ABSTRACT: Facial bone defects can be caused by various causes, such as congenital deformities, iatrogenic results, and trauma. If the size of the bone defect is small, it can be repaired using premanufactured products, but it is not accurate and impossible to restore large bony defect. In the effort to overcome these limitations of premanufac-tured implants, the authors use patient-specific implant (PSI) via computer-aided design/computer-aided manufacturing and 3D printing technologies for facial bone restoration surgery. In this study, the authors use polyetherketoneketone and titanium alloy for implant material among various capable of 3D printing. As a result of analyzing the patients who underwent surgery in this study, PSIs were made in 57 sites for 29 patients. The most common reason for surgery was to improve the patient's esthetics (14 cases), followed by the improvement of iatrogenic complications and postoperative dissatisfaction (11 cases). Restoration of the congenital bony defect was the least (4 cases). Postoperative complications were occurred in 5 patients (screw loosening in 1 case, postoperative dissatisfaction in 3 cases, and postoperative infection in 1 case). There is no case of rejection after implant insertion, because the authors use polyetherketoneketone and titanium alloy for implant material which are good biocompatibility. By using PSIs via 3D technologies, the authors can overcome the limitations of premanufactured products. Moreover, the authors could get better results. So these cutting edge technologies can improve our surgical procedures and predictability.

Correction of Midface Deficiency in Patient With Crouzon Syndrome by Orthognathic Surgery and Patient Specific Facial Implant: Case Report.

ABSTRACT: Crouzon syndrome, also known as craniofacial dysostosis, is an autosomal dominant inherited disease characterized by early cranial fusion and consequential craniofacial malformations. In patients with Crouzon syndrome, the growth of the midface is affected due to early fusion of the cranial base, which results in exophthalmos, ocular ptosis, midface deficiency, and maxillary retrognathism. Frontofacial advancement using Le Fort III osteotomy is the conventional method for treating patients with Crouzon syndrome. However, this procedure has drawbacks such as extensive operation field and high possibility of serious complications (eg, meningitis). For patients with mild symptoms, facial esthetics and proper occlusion can be promoted through conventional orthognathic surgery, but midface deficiency cannot be completely resolved. Thus, in this case report, midface augmentation was performed for a patient with Crouzon syndrome by undergoing conventional orthognathic surgery, along with patient-specific implants made using a 3D virtual technique. Implants were 3D printed using polyetherketoneketone and simultaneously implanted during the orthognathic surgery. After the surgery, not only were the patient's occlusion and facial esthetics improved, but also exophthalmos and ocular ptosis were reduced by the midfacial augmentation effect of patient-specific implants placed in the midface. Since the implants were made exactly as what surgeons have intended through computer-aided design (CAD)/computer-aided manufacturing (CAM) and 3D printing techniques, problems such as under-/over-correction were avoided. In addition, the possibility of implant malpositioning was minimized using surgical stents as implants were passively fitted on the patient's bone surface. This case verified that the application of 3D technology to the field of oral and maxillofacial surgery can reduce the invasiveness of surgery and improve the accuracy of the operation. Therefore, by using cutting-edge technologies, the field of oral and maxillofacial surgery is expected to be developed further in the near future.

Maxillary Total Elongation Surgery using 3D Virtual Surgery, CAD/CAM and 3D Printing Technology: Surgical Convenience and Accuracy.

After Le Fort I osteotomy was first performed by von Langernbeck in 1859, there has been many improvements since. Research on and development of Le Fort I osteotomy procedure has shown downward movement of the maxilla to exhibit lowest stability and accuracy. However, maxillary downgraft movement is necessary in orthognathic patients with insufficient vertical length of the maxilla, but fixation of the maxilla after elongation is often very inaccurate. In this study, the authors utilized 3D virtual surgery, CAD/CAM-assisted 3D printing technology to overcome such limitations of maxillary total elongation. In addition, accuracy at 7 different landmarks from superimposition of virtual simulation data and postoperative Cone-beam computed tomography (CBCT) data were measured. Although posterior maxilla exhibited bigger range of errors, an error of <1 mm was measured at all 7 landmarks. Operation time was greatly shortened with cutting guides and customized plates. Although this study is a single-case study, this study shows increased accuracy and efficacy from application of 3D virtual surgery, CAD/CAM, and 3D printing technology.

Surgical Accuracy of Positioning the Maxilla in Patients With Skeletal Class II Malocclusion Using Computer-Aided Design and Computer-Aided Manufacturing-Assisted Orthognathic Surgery.

OBJECTIVE: To evaluate the surgical accuracy of positioning the maxilla in patients with skeletal class II malocclusion using computer-aided design and computer-aided manufacturing (CAD/ CAM)-assisted orthognathic surgery. MATERIALS AND METHODS: The samples consisted of 10 patients with skeletal class II malocclusion, whose cone-beam computed tomographys taken before and immediately after surgery were available and who underwent bimaxillary orthognathic surgery by a single surgeon using Le Fort I osteotomy and bilateral sagittal split ramus osteotomy at the Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital, Seoul, South Korea between January 2018 and December 2019. After virtual surgical planning was performed using the FACEGIDE system (Korea), surgical cutting guides, intermediate splints, and custom-made titanium mini-plates were fabricated using CAD/CAM technique. Using 8 landmarks (anterior nasal spine, point A, #16, #13, contact point between #11 and #21, #23, #26, posterior nasal spine), the mean differences between the virtually planned (Virtual) and actual postsurgical position of the maxilla (Actual) in the three-dimensional coordinates (ΔActual-Virtual) and their mean absolute deviations were investigated. RESULTS: The mean differences of 8 landmarks were 0.42 mm left side movement in the transverse coordinate, 0.15 mm forward movement in the sagittal coordinate and 0.10 mm downward movement in the vertical coordinate. Their mean absolute deviations were 0.98, 0.67, and 0.62 mm in the sagittal, vertical, and transverse coordinates, respectively. CONCLUSIONS: Since the mean difference was less than 0.5 mm and the range of error was less than 1.0 mm, CAD/CAM-assisted orthognathic surgery might have a high degree of surgical accuracy and clinical relevance in the positioning of the maxilla.

Accuracy of Intentional Change of Frontal Ramal Inclination From Virtual to Actual Orthognathic Surgery Using Computer-Aided Design and Computer-Aided Manufacturing-Made Customized Metal Plates.

OBJECTIVE: To evaluate the accuracy of intentional change of the frontal ramal inclination (FRI) from virtual to actual orthognathic surgery. MATERIALS AND METHODS: A total of 16 patients who underwent orthognathic surgery for correction of facial asymmetry and took cone-beam computed tomography 2 to 3 weeks before surgery (T0) and 3 days after surgery (T1A) were selected. After reorientation of cone-beam computed tomography, the digital imaging and communications in medicine data was converted to StereoLithography format for the merging with dental cast scan using R2GATE software (MegaGen Implant, Daegu, Republic of Korea). During virtual surgery using Geomagic Freeform Plus software (3D Systems, Rock Hill, SC), bilateral FRI discrepancy was corrected (T1V) and 3D-printed surgical wafers and customized metal plates were manufactured using 3D printer (Meg-printer II, MegaGen Implant, Daegu, Republic of Korea) and computer numerical control milling machine (ARDEN, TPS Korea Ltd., Gwangju, Republic of Korea) accordingly. During surgery, FRI correction was done using surgical guide and customized plates. The difference between preoperative and virtually corrected FRI (Δ T1V - T0) and the difference between preoperative and actually surgically corrected FRI (Δ T1A - T0) were measured, and the achieved FRI correction in percentage ([Δ T1A - T0]/[Δ T1V - T0] × 100) was calculated. RESULTS: The mean absolute value of virtual FRI correction (Δ T1V - T0) and actual FRI correction (Δ T1A - T0) were 3.0° and 2.9°, respectively (n = 32). In the increased (medial rotation) FRI group, mean virtual and actual correction amount were 3.2° and 2.8° (n = 17), whereas in the decreased (lateral rotation) group, mean virtual and actual correction amount were -2.7° and -3.1°, respectively (n = 15). No statistically significant difference between virtual and actual measurements were present in either group. The mean achievement rate was 102.8%. Tendency of undercorrection (91.2%) in the increased FRI group and overcorrection (116.0%) in the decreased FRI group were noted. DISCUSSION: With virtual planning and computer-aided design and computer-aided manufacturing-made customized plates, it is possible to correct FRI during orthognathic surgery of patients with facial asymmetry.

Three-Dimensional Changes in the Mandibular Proximal Segment After Using a Surgery-First Approach in Patients With Class III Malocclusion and Facial Asymmetry.

ABSTRACT: This study was performed to evaluate condylar position and angulation after asymmetric mandibular setback between a conventional (CA) and surgery-first approach (SFA) using three-dimensional analysis. The condylar positions of 30 patients with skeletal Class III malocclusion and facial asymmetry who underwent 1-jaw (sagittal split ramus osteotomy) or 2-jaw orthognathic surgery (Le Fort I osteotomy and sagittal split ramus osteotomy) with CA (n = 18) or SFA (n = 12) from 2 university hospitals were studied. The three-dimensional assessment of condylar changes was performed using computed tomography images at the initial time point (T0) and at least 6 months after surgery (T1). Segmentation of condyles and cranial base assessment from cone-beam computed tomography images were performed using ITK-SNAP software (version 3.4.0). Condylar position and angulation changes were calculated using 3D Slicer software (version 4.10.2), and statistical analysis was performed. No significant translational or rotational condylar changes were observed between the deviated and non-deviated sides in each group or between the CA and SFA groups except yaw ( p = 0.014). Linear mixed-model analysis and multi-variate analysis showed no significant difference between the CA and SFA groups. Surgery-first approach might not be associated with more harmful effects on the condylar position and angulation changes as compared with CA.

Critical issues concerning biocreative strategy in contemporary temporary skeletal anchorage device orthodontics: A narrative review.

Biocreative Orthodontic Strategy (BOS) is designed to establish a physiologically stable occlusion in harmony with masticatory and TMJ function and healthy supporting tissues with strategic use of temporary skeletal anchorage devices (TSADs). This narrative review surveys current research that demonstrates how BOS with TSADs uses a target approach to overcome the limitations experienced with conventional orthodontic treatment. A narrative review article including research on TSADs orthodontics in the permanent dentition. This review is a brief survey of five BOS principles for contemporary TSAD orthodontics: elegant selection of TSADs, bracket prescription to enhance TSAD orthodontics, antero-posterior dimension control, transverse dimension control and airway control issues. Severe malocclusion and craniofacial dysmorphology can be treated with Biocreative Orthodontic Strategy with a minimum number of TSADs. In order to achieve successful treatment outcome using TSADs, it is critical to understand the key diagnosis and treatment principles of BOS and how to develop a target approach for the tooth and bone movement.

Three-Dimensional Facial Soft Tissue Changes After Orthognathic Surgery in Cleft Patients Using Artificial Intelligence-Assisted Landmark Autodigitization.

ABSTRACT: The purpose of this study was to investigate three-dimensional facial soft tissue changes after bimaxillary orthognathic surgery (BOGS) in patients with cleft lip and palate. The samples consisted of 34 Korean young adult patients with skeletal class III malocclusion who underwent BOGS for maxillary advancement/posterior impaction and mandibular setback. They were divided into cleft-class III (C-CIII) group (n = 18) and noncleft-class III (NC-CIII) group (n = 16). Three-dimensional computed tomography images were taken 1 month before (T1) and 3 months after (T2) surgery. After 34 hard/soft tissue landmarks were automatically identified using software, the amount and direction of change in landmarks and the amount of change in 16 soft tissue variables during T1-T2 were calculated. Then, statistical analysis was performed. Compared to NC-CIII group, C-CIII group showed more posteriorly-positioned hard/soft tissue landmarks, larger alar width, alar base width and philtrum width, and more obtuse nasal tip angle at both T1 and T2 stages. C-CIII group exhibited higher soft-to-hard tissue movement ratios at the bottom of the nose (ΔSn/ΔANS, 1.08 versus 0.81) and the upper part of the upper lip (ΔPoint A'/ΔPoint A, 1.08 versus 0.91), but a lower ratio at the lower part of the upper lip (ΔLs'/ΔIs, 0.72 versus 1.01) than NC-CIII group. The number of hard-soft tissue landmarks with high correlation (>0.90) was smaller in C-CIII group than in NC-CIII group (2 versus 6). Scar tissues and abnormal muscles in the nose and upper lip might elicit different responses in the nasolabial soft tissues to BOGS between C-CIII and NC-CIII patients.

Evaluation of Periodontal Risk Factors with Quantitative Light-Induced Fluorescence Based Fluorescent Plaque Index, in Comparison to Radiographic and Oral Health Habit Scoring: A Retrospective Case Study.

The aim of this study was to evaluate periodontal risk factors with oral health habits and fluorescent plaque index (FPI) using quantitative light-induced fluorescence (QLF) images, and to evaluate their effect on the degree of radiographic bone loss (RBL). Selected were 276 patients over 19 years of age to complete the questionnaire for oral health habit and take QLF images, periapical and panoramic radiographs. Oral health habit score, age, and sex showed a statistically significant correlation with FPI. FPI showed a lower value as the oral health habit score increased and the age decreased. Moreover, females showed lower FPI values than did males. RBL showed a statistically significant positive correlation with age but did not show any correlation with oral health habit scores and sex. There was no correlation between FPI and RBL. The results of this study suggest that the clinical use of QLF allows plaque detection by non-invasive procedures and can aid in a more objective estimation for oral hygiene status.

Three-Dimensional Digital Superimposition of Orthodontic Bracket Position by Using a Computer-Aided Transfer Jig System: An Accuracy Analysis.

Accurate bracket placement is essential for successful orthodontic treatment. An indirect bracket bonding system (IDBS) has been developed to ensure proper bracket positioning with three-dimensional computer-aided transfer jigs. The purpose of this study was to investigate the accuracy of bracket positioning by a one-body transfer jig according to the tooth type and presence/absence of a resin base. In total, 506 teeth from 20 orthodontic patients were included in this study. After initial dental models were scanned, virtual setup and bracket positioning procedures were performed with 3D software. Transfer jigs and RP models were fabricated with a 3D printer, and brackets were bonded to the RP model with or without resin base fabrication. The best-fit method of 3D digital superimposition was used to evaluate the lineal and angular accuracy of the actual bracket position compared to a virtual bracket position. Although all the measurements showed significant differences in position, they were clinically acceptable. Regarding the tooth types, premolars and molars showed higher accuracy than anterior teeth. The presence or absence of a resin base did not consistently affect the accuracy. In conclusion, the proper application of IDBS should be performed considering the errors, and resin base fabrication might not be essential in ensuring high-accuracy IDBS.