Common dental anomalies in Korean orthodontic patients: An update / 대한치과교정학회지

Objective@#The aim of this study was 1) to investigate the prevalence and pattern of dental anomalies (DAs), 2) to compare DAs according to the type of malocclusion, and 3) to investigate the correlation between tooth impaction and other DAs in the Korean orthodontic population. @*Methods@#A total of 3,240 orthodontic patients were classified as Class I, Class II, or Class III malocclusion groups. The presence and location of common DAs, including impaction, microdontia, agenesis, supernumerary tooth, transposition, and fusion, were identified by examining diagnostic records. Furthermore, samples were classified as Group 1 without impaction or Group 2 with impaction. The prevalence of other DAs concurrent with impaction was investigated and compared to Group 1. @*Results@#Impaction was the most prevalent DA, followed by microdontia, agenesis, and supernumerary. Class I and Class III groups showed the same order of prevalence, but agenesis was more frequent than microdontia in the Class II group. The prevalence of the four DAs was lowest in the Class III group. Overall, 8.6% of patients were classified into Group 2. The incidence of DAs other than impaction and the prevalence of multiple concurrent DAs were significantly higher in Group 2. Impaction showed a significant relationship with supernumerary tooth, transposition, and fusion. @*Conclusions@#The prevalence and pattern of DAs varied depending on the type of malocclusion. As there was a higher risk of other DAs in patients with impacted teeth, early detection of the impacted tooth and a detailed diagnosis of other possible DAs may be essential.

Comparison of the effects of horizontal and vertical micro-osteoperforations on the biological response and tooth movement in rabbits / 대한치과교정학회지

Objective@#This study aimed to compare the amount of tooth movement after multiple horizontal (MH) and single vertical (SV) micro-osteoperforations (MOPs), and evaluate the histological changes after orthodontic force application in rabbits. @*Methods@#The mandibles of 24 white rabbits were subjected to two experimental interventions: MH and SV MOPs. Defect volume of the MOPs between the two groups was kept similar. A force of 100 cN was applied via a coil spring between the incisor teeth and the first premolars. The amount of tooth movement was measured. Differences in the amount of tooth movement and bone variables at three time points and between the two groups were evaluated using repeated-measures analysis of variance. @*Results@#The first premolar showed a mesial movement of 1.47 mm in the MH group and 1.84 mm in the SV group, which was significantly different at Week 3 (p < 0.05). No significant difference was observed in bone volume and bone fraction between the groups. Tartrate-resistant acidic phosphatase-positive cell count was also significantly greater at Week 3 than at Week 1 in both the SV and MH groups. @*Conclusions@#The amount of tooth movement showed significant differences between Weeks 1 and 3 in the SV and MH MOP groups, but showed no differences between the two groups. Therefore, SV MOP could be considered an effective tool for enhancing tooth movement, especially for molar distalization, uprighting, and protraction to an edentulous area.

The global distribution of permanent canine hypodontia: A systematic review / 대한치과교정학회지

Objective@#To systematically review studies on canine agenesis prevalence in different populations and continents, based on the jaw, sex, location, and associated dental anomalies. @*Methods@#Electronic and hand searches of English literature in PubMed, Web of Science, Scopus, OpenGrey, and Science Direct were conducted, and the authors were contacted when necessary. Observational studies (population-based, hospital/clinic-based, and cross-sectional) were included. For study appraisal and synthesis, duplicate selection was performed independently by two reviewers. Study quality was assessed using a modified Strengthening the Reporting of Observational Studies in Epidemiology checklist, with main outcome of prevalence of canine agenesis. @*Results@#The global population prevalence of canine agenesis was 0.30% (0.0−4.7%), highest in Asia (0.54%), followed by Africa (0.33%), and the least in Europe and South America (0.19% in both continents). Canine agenesis was more common in the maxilla (88.57%), followed by both maxilla and mandible (8.57%), and the least common was mandible-only presentation (2.86%). The condition was more common in females (female:male ratio = 1.23), except in Asia (female:male ratio = 0.88) and Africa (female:male ratio = 1). In Asia, unilateral agenesis was almost twice as prevalent as bilateral, but in Europe, the bilateral form was more common. @*Conclusions@#The overall prevalence of canine agenesis is 0.30%, with the highest prevalence in Asia, followed by Africa, Europe, and South America.The condition is more common in the maxilla than the mandible, and in females than males (except in Asia and Africa), with unilateral agenesis being more common in Asia and the bilateral form showing a greater prevalence in Europe.

Comparison of the effects of horizontal and vertical micro-osteoperforations on the biological response and tooth movement in rabbits / 대한치과교정학회지

Objective@#This study aimed to compare the amount of tooth movement after multiple horizontal (MH) and single vertical (SV) micro-osteoperforations (MOPs), and evaluate the histological changes after orthodontic force application in rabbits. @*Methods@#The mandibles of 24 white rabbits were subjected to two experimental interventions: MH and SV MOPs. Defect volume of the MOPs between the two groups was kept similar. A force of 100 cN was applied via a coil spring between the incisor teeth and the first premolars. The amount of tooth movement was measured. Differences in the amount of tooth movement and bone variables at three time points and between the two groups were evaluated using repeated-measures analysis of variance. @*Results@#The first premolar showed a mesial movement of 1.47 mm in the MH group and 1.84 mm in the SV group, which was significantly different at Week 3 (p < 0.05). No significant difference was observed in bone volume and bone fraction between the groups. Tartrate-resistant acidic phosphatase-positive cell count was also significantly greater at Week 3 than at Week 1 in both the SV and MH groups. @*Conclusions@#The amount of tooth movement showed significant differences between Weeks 1 and 3 in the SV and MH MOP groups, but showed no differences between the two groups. Therefore, SV MOP could be considered an effective tool for enhancing tooth movement, especially for molar distalization, uprighting, and protraction to an edentulous area.

The global distribution of permanent canine hypodontia: A systematic review / 대한치과교정학회지

Objective@#To systematically review studies on canine agenesis prevalence in different populations and continents, based on the jaw, sex, location, and associated dental anomalies. @*Methods@#Electronic and hand searches of English literature in PubMed, Web of Science, Scopus, OpenGrey, and Science Direct were conducted, and the authors were contacted when necessary. Observational studies (population-based, hospital/clinic-based, and cross-sectional) were included. For study appraisal and synthesis, duplicate selection was performed independently by two reviewers. Study quality was assessed using a modified Strengthening the Reporting of Observational Studies in Epidemiology checklist, with main outcome of prevalence of canine agenesis. @*Results@#The global population prevalence of canine agenesis was 0.30% (0.0−4.7%), highest in Asia (0.54%), followed by Africa (0.33%), and the least in Europe and South America (0.19% in both continents). Canine agenesis was more common in the maxilla (88.57%), followed by both maxilla and mandible (8.57%), and the least common was mandible-only presentation (2.86%). The condition was more common in females (female:male ratio = 1.23), except in Asia (female:male ratio = 0.88) and Africa (female:male ratio = 1). In Asia, unilateral agenesis was almost twice as prevalent as bilateral, but in Europe, the bilateral form was more common. @*Conclusions@#The overall prevalence of canine agenesis is 0.30%, with the highest prevalence in Asia, followed by Africa, Europe, and South America.The condition is more common in the maxilla than the mandible, and in females than males (except in Asia and Africa), with unilateral agenesis being more common in Asia and the bilateral form showing a greater prevalence in Europe.

Changes in maximum lip-closing force after extraction and nonextraction orthodontic treatments / 대한치과교정학회지

OBJECTIVE@#The aims of the present study were to evaluate the changes in the maximum lip-closing force (MLF) after orthodontic treatment with or without premolar extractions and verify the correlation of these changes with dentoskeletal changes.@*METHODS@#In total, 17 women who underwent nonextraction orthodontic treatment and 15 women who underwent orthodontic treatment with extraction of all four first premolars were included in this retrospective study. For all patients, lateral cephalograms and dental models were measured before (T0) and after (T1) treatment. In addition, MLF was measured at both time points using the Lip De Cum LDC-110R® device. Statistical analyses were performed to evaluate changes in clinical variables and MLF and their correlations.@*RESULTS@#Both groups showed similar skeletal patterns, although the extraction group showed greater proclination of the maxillary and mandibular incisors and lip protrusion compared to the nonextraction group at T0. MLF at T0 was comparable between the two groups. The reduction in the arch width and depth and incisor retroclination from T0 to T1 were more pronounced in the extraction group than in the nonextraction group. MLF in the extraction group significantly increased during the treatment period, and this increase was significantly greater than that in the nonextraction group. The increase in MLF was found to be correlated with the increase in the interincisal angle and decrease in the intermolar width, arch depth, and incisor–mandibular plane angle.@*CONCLUSIONS@#This study suggests that MLF increases to a greater extent during extraction orthodontic treatment than during nonextraction orthodontic treatment.

Distalization with a modified C-palatal plate for severe upper crowding and a missing lower incisor / 대한치과교정학회지

This case report presents the orthodontic treatment of a 25-year-old patient with skeletal Class II and severe maxillary arch crowding, moderate mandibular arch crowding, anterior crossbite, and a missing lower incisor. He was treated with molar distalization using a modified C-palatal plate and temporary anchorage devices to create sufficient space for retraction. The total treatment duration was 21 months. After treatment, his occlusion and smile esthetics showed significant improvement. The modified C-palatal plate represents a treatment modality that enhances the prospects of non-extraction treatment and reduces the need for extraction.

Palatal en-masse retraction of segmented maxillary anterior teeth: A finite element study / 대한치과교정학회지

OBJECTIVE@#The aim of this finite element study was to clarify the mechanics of tooth movement in palatal en-masse retraction of segmented maxillary anterior teeth by using anchor screws and lever arms.@*METHODS@#A three-dimensional finite element method was used to simulate overall orthodontic tooth movements. The line of action of the force was varied by changing both the lever arm height and anchor screw position.@*RESULTS@#When the line of action of the force passed through the center of resistance (CR), the anterior teeth showed translation. However, when the line of action was not perpendicular to the long axis of the anterior teeth, the anterior teeth moved bodily with an unexpected intrusion even though the force was transmitted horizontally. To move the anterior teeth bodily without intrusion and extrusion, a downward force passing through the CR was necessary. When the line of action of the force passed apical to the CR, the anterior teeth tipped counterclockwise during retraction, and when the line of action of the force passed coronal to the CR, the anterior teeth tipped clockwise during retraction.@*CONCLUSIONS@#The movement pattern of the anterior teeth changed depending on the combination of lever arm height and anchor screw position. However, this pattern may be unpredictable in clinical settings because the movement direction is not always equal to the force direction.

Comparison of tooth movement and biological response in corticotomy and micro-osteoperforation in rabbits / 대한치과교정학회지

OBJECTIVE@#The aim of this study was to evaluate the amount of tooth movement and histologic changes with different corticotomy designs and micro-osteoperforation in rabbits.@*METHODS@#The sample consisted of 24 rabbits divided into three experimental groups (triangular corticotomy [TC] and indentation corticotomy [IC] with flap, and flapless micro-osteoperforations [MP]) and a control. A traction force of 100 cN was applied by connecting the first premolars to the incisors. The amount of tooth movement was measured. Kruskal-Wallis test was used to assess differences in tooth movement between the groups. Micro-computed tomography, hematoxylin and eosin staining, and tartrate-resistant acidic phosphatase (TRAP) analysis were performed. Analysis of variance was applied to assess differences in TRAP-positive osteoclast count between the groups.@*RESULTS@#The amount of tooth movement increased by 46.5% and 32.0% in the IC and MP groups, respectively, while the bone fraction analysis showed 69.7% and 8.5% less mineralization compared to the control. There were no significant intergroup differences in the number of TRAP-positive osteoclasts.@*CONCLUSIONS@#The micro-osteoperforation group showed no significant differences in the amount of tooth movement compared to the corticotomy groups, nor in the TRAP-positive osteoclast count compared to both corticotomy groups and control.

Displacement and stress distribution of the maxillofacial complex during maxillary protraction using palatal plates: A three-dimensional finite element analysis / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to analyze initial displacement and stress distribution of the maxillofacial complex during dentoskeletal maxillary protraction with various appliance designs placed on the palatal region by using three-dimensional finite element analysis. METHODS: Six models of maxillary protraction were developed: conventional facemask (Type A), facemask with dentoskeletal hybrid anchorage (Type B), facemask with a palatal plate (Type C), intraoral traction using a Class III palatal plate (Type D), facemask with a palatal plate combined with rapid maxillary expansion (RME; Type E), and Class III palatal plate intraoral traction with RME (Type F). In Types A, B, C, and D, maxillary protraction alone was performed, whereas in Types E and F, transverse expansion was performed simultaneously with maxillary protraction. RESULTS: Type C displayed the greatest amount of anterior dentoskeletal displacement in the sagittal plane. Types A and B resulted in similar amounts of anterior displacement of all the maxillofacial landmarks. Type D showed little movement, but Type E with expansion and the palatal plate displayed a larger range of movement of the maxillofacial landmarks in all directions. CONCLUSIONS: The palatal plate served as an effective skeletal anchor for use with the facemask in maxillary protraction. In contrast, the intraoral use of Class III palatal plates showed minimal skeletal and dental effects in maxillary protraction. In addition, palatal expansion with the protraction force showed minimal effect on the forward movement of the maxillary complex.

Comparison of treatment effects between four premolar extraction and total arch distalization using the modified C-palatal plate / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to compare the skeletal, dental, and soft-tissue treatment effects of nonextraction therapy using the modified C-palatal plate (MCPP) to those of premolar extraction (PE) treatment in adult patients with Class II malocclusion. METHODS: Pretreatment and posttreatment lateral cephalographs of 40 adult patients with Class II malocclusion were retrospectively analyzed. The MCPP group comprised 20 patients treated with total arch distalization of the maxillary arch while the PE group comprised 20 patients treated with four PE. Fifty-eight linear and angular measurements were analyzed to assess the changes before and after treatment. Descriptive statistics, paired t-test, and multivariate analysis of variance were performed to evaluate the treatment effects within and between the two groups. RESULTS: The MCPP group presented 3.4 mm of retraction, 1.0 mm of extrusion, and 7.3° lingual inclination of the maxillary central incisor. In comparison, the PE group displayed greater amount of maxillary central incisor retraction and retroclination, mandibular incisor retraction, and upper lip retraction (5.3 mm, 14.8°, 5.1 mm, and 2.0 mm, respectively; p < 0.001 for all). In addition, the MCPP group showed 4.0 mm of distalization and 1.3 mm of intrusion with 2.9° distal tipping of the maxillary first molars. CONCLUSIONS: These findings suggest the MCPP is an effective distalization appliance in the maxillary arch. The amount of incisor retraction, however, was significantly higher in the PE group. Therefore, four PE may be recommended when greater improvement of incisor position and soft-tissue profile is required.

Comparison of treatment effects between the modified C-palatal plate and cervical pull headgear for total arch distalization in adults / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to evaluate the dental and skeletal effects of the modified C-palatal plate (MCPP) for total arch distalization in adult patients with Class II malocclusion and compare the findings with those of cervical pull headgear. METHODS: The study sample consisted of the lateral cephalograms of 44 adult patients with Class II Division 1 malocclusion, including 22 who received treatment with MCPP (age, 24.7 ± 7.7 years) and 22 who received treatment with cervical pull headgear (age, 23.0 ± 7.7 years). Pre- (T1) and post-treatment (T2) cephalograms were analyzed for 24 linear and angular measurements. Multivariate analysis of variance was performed to evaluate the changes after treatment in each group and differences in treatment effects between the two groups. RESULTS: The mean amount of distalization at the crown and root levels of the maxillary first molar and the amount of distal tipping was 4.2 mm, 3.5 mm, and 3.9° in the MCPP group, and 2.3 mm, 0.6 mm, and 8.6° in the headgear group, respectively. In addition, intrusion by 2.5 mm was observed in the MCPP group. In both groups, the distal movement of the upper lip and the increase in the nasolabial angle were statistically significant (p < 0.001). However, none of the skeletal and soft tissue variables exhibited significant differences between the two groups. CONCLUSIONS: The results of this study suggest that MCPP is an effective treatment modality for total arch distalization in adults.

A three-dimensional photogrammetric analysis of the facial esthetics of the Miss Korea pageant contestants / 대한치과교정학회지

OBJECTIVE: The aims of this study were to measure and compare the facial dimensions of the Miss Korea pageant contestants and a selected group of women from the general population by using three-dimensional (3D) image analysis, as well as to compare various facial ratios to the golden ratio within each group. METHODS: Three-dimensional images of 52 Miss Korea pageant contestants (MK group) and 41 young female adults selected from the general population (GP group) were acquired. Fifty-four variables and ratios were measured and calculated. Intergroup comparisons were performed using multivariate analysis of variance. RESULTS: Compared to the GP group, the MK group showed greater total facial height and eye width, lesser lower-facial height, and lesser facial, lower-facial, and nasal widths. Moreover, compared to the GP group, the MK group had more protruded noses with greater nasolabial angle, greater vertical curvature of the foreheads, lesser horizontal curvature of the cheek, and lesser lower-lip-and-chin volume. CONCLUSIONS: The MK group had longer faces but smaller lower lips and chins than did the GP group. The golden ratio was not matching the current facial esthetic standards. These data might be beneficial for treatment planning of patients undergoing orthognathic and plastic surgeries.

The Improvement and Completion of Outcome index: A new assessment system for quality of orthodontic treatment / 대한치과교정학회지

OBJECTIVE: Given the considerable disagreement between the Peer Assessment Rating (PAR) index and the American Board of Orthodontics Cast-Radiograph Evaluation, we aimed to develop a novel assessment system-the Improvement and Completion of Outcome (ICO) index-to evaluate the outcome of orthodontic treatment. METHODS: Sixteen criteria from 4 major categories were established to represent the pretreatment malocclusion status, as well as the degree of improvement and level of completion of outcome during/after treatment: dental relationship (arch length discrepancy, irregularity, U1-SN, and IMPA); anteroposterior relationship (overjet, right and left molar position, ANB); vertical relationship (anterior overbite, anterior open-bite, lateral open-bite, SN-MP); and transverse relationship (dental midline discrepancy, chin point deviation, posterior cross-bite, occlusal plane cant). The score for each criterion was defined from 0 or −1 (worst) to 5 (ideal value or normal occlusion) in gradations of 1. The sum of the scores in each category indicates the area and extent of the problems. Improvement and completion percentages were estimated based on the pre- and post-treatment total scores and the maximum total score. If the completion percentage exceeded 80%, treatment outcome was considered successful. RESULTS: Two cases, Class I malocclusion and skeletal Class III malocclusion, are presented to represent the assessment procedure using the ICO index. The difference in the level of improvement and completion of treatment outcome can be clearly explained by using 2 percentage values. CONCLUSIONS: Thus, the ICO index enables the evaluation of the quality of orthodontic treatment objectively and consecutively throughout the entire treatment process.

A three-dimensional finite element analysis of molar distalization with a palatal plate, pendulum, and headgear according to molar eruption stage / 대한치과교정학회지

OBJECTIVE: This study aimed to (1) evaluate the effects of maxillary second and third molar eruption status on the distalization of first molars with a modified palatal anchorage plate (MPAP), and (2) compare the results to the outcomes of the use of a pendulum and that of a headgear using three-dimensional finite element analysis. METHODS: Three eruption stages were established: an erupting second molar at the cervical one-third of the first molar root (Stage 1), a fully erupted second molar (Stage 2), and an erupting third molar at the cervical one-third of the second molar root (Stage 3). Retraction forces were applied via three anchorage appliance models: an MPAP with bracket and archwire, a bone-anchored pendulum appliance, and cervical-pull headgear. RESULTS: An MPAP showed greater root movement of the first molar than crown movement, and this was more noticeable in Stages 2 and 3. With the other devices, the first molar showed distal tipping. Transversely, the first molar had mesial-out rotation with headgear and mesial-in rotation with the other devices. Vertically, the first molar was intruded with an MPAP, and extruded with the other appliances. CONCLUSIONS: The second molar eruption stage had an effect on molar distalization, but the third molar follicle had no effect. The application of an MPAP may be an effective treatment option for maxillary molar distalization.

Treatment effects of mandibular total arch distalization using a ramal plate / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to evaluate treatment effects after distalization of the mandibular dentition using ramal plates through lateral cephalograms. METHODS: Pre- and post-treatment lateral cephalograms and dental casts of 22 adult patients (11 males and 11 females; mean age, 23.9 ± 5.52 years) who received ramal plates for mandibular molar distalization were analyzed. The treatment effects and amount of distalization of the mandibular molars were calculated and tested for statistical significance. The significance level was set at p < 0.001. RESULTS: The mandibular first molar distalization at the crown and root were 2.10 mm (p < 0.001) and 0.81 mm (p = 0.011), respectively. In the evaluation of skeletal variables, there was a significant increase in the Wits appraisal (p < 0.001). In the evaluation of the soft tissue, there was no significant effect on upper lip position, but the lower lips showed a significant retraction of 2.2 mm (p < 0.001). CONCLUSIONS: The mandibular molars showed a significant amount of distalization accompanied by limited extrusion and mesiobuccal rotation of the crowns. A ramal plate may be a viable device for mandibular total arch distalization in Class III patients who are reluctant to undergo orthognathic surgery.

Evaluation of the facial dimensions of young adult women with a preferred facial appearance / 대한치과교정학회지

OBJECTIVE: The aim of this study was to evaluate the facial dimensions of young adult women with a preferred facial appearance and compare the results with those from the general population. METHODS: Twenty-five linear, nine angular, and three area measurements were made and four ratios were calculated using a sample of standardized frontal and lateral photographs of 46 young adult women with a preferred facial appearance (Miss Korea group) and 44 young adult women from the general population (control group). Differences between the two groups were analyzed using multivariate analysis of variance (MANOVA). RESULTS: Compared with the control group, the Miss Korea group exhibited a significantly greater facial height, total facial height (TFH; trichion-menton), facial width (tragus right-tragus left), facial depth (tragus-true vertical line), and trichion-nasion/TFH ratio and smaller subnasale-menton/TFH and facial width/TFH ratios. Furthermore, the control group had smaller intercanthal and interpupillary widths. CONCLUSIONS: The Miss Korea group exhibited longer, wider, and deeper faces compared with those from the general population. Furthermore, the Miss Korea group had larger eyes, longer but less protruded noses, longer and more retruded lower lips and chins, larger lip vermilion areas, and smaller labiomental angles. These results suggest that the latest trends in facial esthetics should be considered during diagnosis and treatment planning for young women with dentofacial abnormalities.

New classification of lingual arch form in normal occlusion using three dimensional virtual models / 대한치과교정학회지

OBJECTIVE: The purposes of this study were 1) to classify lingual dental arch form types based on the lingual bracket points and 2) to provide a new lingual arch form template based on this classification for clinical application through the analysis of three-dimensional virtual models of normal occlusion sample. METHODS: Maxillary and mandibular casts of 115 young adults with normal occlusion were scanned in their occluded positions and lingual bracket points were digitized on the virtual models by using Rapidform 2006 software. Sixty-eight cases (dataset 1) were used in K-means cluster analysis to classify arch forms with intercanine, interpremolar and intermolar widths and width/depth ratios as determinants. The best-fit curves of the mean arch forms were generated. The remaining cases (dataset 2) were mapped into the obtained clusters and a multivariate test was performed to assess the differences between the clusters. RESULTS: Four-cluster classification demonstrated maximum intercluster distance. Wide, narrow, tapering, and ovoid types were described according to the intercanine and intermolar widths and their best-fit curves were depicted. No significant differences in arch depths existed among the clusters. Strong to moderate correlations were found between maxillary and mandibular arch widths. CONCLUSIONS: Lingual arch forms have been classified into 4 types based on their anterior and posterior dimensions. A template of the 4 arch forms has been depicted. Three-dimensional analysis of the lingual bracket points provides more accurate identification of arch form and, consequently, archwire selection.

New classification of lingual arch form in normal occlusion using three dimensional virtual models / 대한치과교정학회지

OBJECTIVE: The purposes of this study were 1) to classify lingual dental arch form types based on the lingual bracket points and 2) to provide a new lingual arch form template based on this classification for clinical application through the analysis of three-dimensional virtual models of normal occlusion sample. METHODS: Maxillary and mandibular casts of 115 young adults with normal occlusion were scanned in their occluded positions and lingual bracket points were digitized on the virtual models by using Rapidform 2006 software. Sixty-eight cases (dataset 1) were used in K-means cluster analysis to classify arch forms with intercanine, interpremolar and intermolar widths and width/depth ratios as determinants. The best-fit curves of the mean arch forms were generated. The remaining cases (dataset 2) were mapped into the obtained clusters and a multivariate test was performed to assess the differences between the clusters. RESULTS: Four-cluster classification demonstrated maximum intercluster distance. Wide, narrow, tapering, and ovoid types were described according to the intercanine and intermolar widths and their best-fit curves were depicted. No significant differences in arch depths existed among the clusters. Strong to moderate correlations were found between maxillary and mandibular arch widths. CONCLUSIONS: Lingual arch forms have been classified into 4 types based on their anterior and posterior dimensions. A template of the 4 arch forms has been depicted. Three-dimensional analysis of the lingual bracket points provides more accurate identification of arch form and, consequently, archwire selection.

New approach of maxillary protraction using modified C-palatal plates in Class III patients / 대한치과교정학회지

Maxillary protraction is the conventional treatment for growing Class III patients with maxillary deficiency, but it has undesirable dental effects. The purpose of this report is to introduce an alternative modality of maxillary protraction in patients with dentoskeletal Class III malocclusion using a modified C-palatal plate connected with elastics to a face mask. This method improved skeletal measurements, corrected overjet, and slightly improved the profile. The patients may require definitive treatment in adolescence or adulthood. The modified C-palatal plate enables nonsurgical maxillary advancement with maximal skeletal effects and minimal dental side effects.