OBJECTIVE: The purpose of this study was to assess new three-dimensional (3D) cephalometric variables, and to evaluate the relationships among skeletal and dentoalveolar variables through 3D cephalometric analysis. METHODS: Cone-beam computed tomography (CBCT) scans were acquired from 38 young adults (18 men and 20 women; 22.6 +/- 3.2 years) with normal occlusion. Thirty-five landmarks were digitized on the 3D-rendered views. Several measurements were obtained for selected landmarks. Correlations among different variables were calculated by means of Pearson's correlation coefficient values. RESULTS: The body of the mandible had a longer curve length in men (102.3 +/- 4.4 mm) than in women (94.5 +/- 4.7 mm) (p < 0.001), but there was no significant difference in the maxillary basal curve length. Men had significantly larger facial dimensions, whereas women had a larger gonial angle (117.0 +/- 4.0 vs. 113.8 +/- 3.3; p < 0.001). Strong-to-moderate correlation values were found among the vertical and transverse variables (r = 0.71 to 0.51). CONCLUSIONS: The normative values of new 3D cephalometric parameters, including the maxillary and mandibular curve length, were obtained. Strong-to-moderate correlation values were found among several vertical and transverse variables through 3D cephalometric analysis. This method of cephalometric analyses can be useful in diagnosis and treatment planning for patients with dentofacial deformities.
Adult ; Cone-Beam Computed Tomography ; Dentofacial Deformities ; Female ; Humans ; Male ; Mandible ; Young Adult

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.
Finite Element Analysis* ; Palatal Expansion Technique ; Traction

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.
Adult ; Bicuspid* ; Humans ; Incisor ; Lip ; Malocclusion ; Molar ; Multivariate Analysis ; Retrospective Studies

OBJECTIVE: This study was aimed at comparing the mandibular arch forms of Korean and Vietnamese patients by using facial axis (FA) points on three-dimensional (3D) models. METHODS: Mandibular casts of 68 Korean (Class I malocclusion, 30; Class II malocclusion, 38) and 78 Vietnamese (Class I malocclusion, 41; Class II malocclusion, 37) patients were scanned in their occluded positions and grouped according to arch form (tapered, ovoid, and square). The FA point of each tooth was digitized on the 3D mandibular models. The measurements and frequency distributions of the arch forms were compared between the ethnic groups. RESULTS: The Vietnamese patients had significantly greater intercanine depth and intercanine and intermolar width-to-depth ratios than the Korean patients (p < 0.05). The frequency distributions of the arch forms were also significantly different (p = 0.038), but no sexual dimorphism was found. CONCLUSIONS: Vietnamese people tend to have deeper and wider arches than Korean people. The three arch forms are evenly distributed in Korean people, but Vietnamese people frequently have square arches. Clinicians should identify the correct arch form of an ethnic group before initiating orthodontic treatment.
Asian Continental Ancestry Group* ; Axis, Cervical Vertebra* ; Ethnic Groups ; Humans ; Malocclusion ; Tooth

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.
Adult ; Cheek ; Chin ; Esthetics* ; Female ; Forehead ; Humans ; Imaging, Three-Dimensional ; Korea* ; Lip ; Multivariate Analysis ; Nose ; Plastics

OBJECTIVE: To determine Korean facial profile preferences based on lip position as assessed by Hispanic-Americans of varying western adaptation levels and to determine whether the age and sex of the rater had any influence. METHODS: For this study, 132 Hispanic-Americans and 68 Caucasians of varying age, sex and western adaptation levels volunteered to rate their preference of Korean male and female facial silhouettes having lips ranging from retruding to protruding. The Hispanic-Americans were also asked to complete a Bidimensional Acculturation Scale questionnaire to determine their western adaptation status: low-acculturated Hispanics (LAH; lesser western-adapted Hispanic participants) or high-acculturated Hispanics (HAH; higher western-adapted Hispanic participants). RESULTS: The LAHs preferred significantly more retruded lip positions (p < 0.05) while HAHs showed some similarities with Caucasian participants in the results for the Korean male profile, even though HAHs preferred more retruded lip positions for the Korean female profile than Caucasians did (p < 0.05). The age and sex of raters did not influence the preference of facial profiles (p > 0.05). CONCLUSIONS: The results of this study suggest that Hispanic-Americans prefer a flatter Korean lip profile. It would be prudent for orthodontists to offer patients the option of altering lip profile through orthodontic and/or orthognathic surgery treatments.
Acculturation ; Female ; Hispanic Americans ; Humans ; Lip ; Male ; Orthodontics ; Orthognathic Surgery ; Surveys and Questionnaires

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.
Crowns ; Finite Element Analysis* ; Molar* ; Molar, Third

OBJECTIVE: This study aimed to evaluate the effect of an intentionally created socket on bone remodeling with orthodontic tooth movement in rabbits. METHODS: Eighteen male rabbits weighing 3.8 - 4.25 kg were used. An 8-mm deep and 2-mm wide socket was drilled in the bone 1 mm mesial to the right mandibular first premolar. The left first premolar was extracted to serve as an extraction socket. A traction force of 100 cN was applied to the right first premolar and left second premolar. Sections were obtained at the middle third of the moving tooth for both the drilled and extraction sockets and evaluated with hematoxylin and eosin staining and immunohistochemical analyses. The amount of tooth movement and tartrate-resistant acid phosphatase (TRAP)-positive cell count were compared between the 2 groups using the Mann-Whitney U test. RESULTS: At week 2, the distance of tooth movement was significantly higher in the intentional socket group (p < 0.05) than in the extraction socket group. The number of TRAP-positive cells decreased in week 2 but increased in week 3 (p < 0.05). However, there were no significant differences between the groups. Furthermore, results of transforming growth factor (TGF)-beta staining revealed no significant differences. CONCLUSIONS: The intentional socket group showed greater distance of tooth movement than did the extraction socket group at week 2. Osteoclast counts and results of immunohistochemical analyses suggested elevated bone remodeling in both the groups. Thus, osteotomy may be an effective modality for enhancing tooth movement in orthodontic treatment.
Acid Phosphatase ; Bicuspid ; Bone Remodeling ; Cell Count ; Eosine Yellowish-(YS) ; Hematoxylin ; Humans ; Intention ; Isoenzymes ; Male ; Mandrillus ; Osteoclasts ; Osteotomy ; Rabbits ; Tooth ; Tooth Movement ; Traction ; Transforming Growth Factors

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.
Classification* ; Cluster Analysis ; Dental Arch ; Humans ; Young Adult

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.
Classification* ; Cluster Analysis ; Dental Arch ; Humans ; Young Adult