• The korean journal of orthodontics
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• v.54 no.3
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• pp.142-152
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• 2024

Objective: This retrospective cohort study aimed to assess and compare the accuracy of 3 different Invisalign^® treatment regimens in terms of variations of aligner change frequency and type of aligner material in achieving maxillary dental buccal expansion. Methods: Altogether, 120 adult patients whose treatment involved maxillary dental expansion with Invisalign^® were included. The patients were divided into 3 groups, with each group comprising 40 patients as follows: SmartTrack^® 1-week changes (ST1), SmartTrack^® 2-week changes (ST2), and EX30^® 2-week changes (EX2). The groups were assessed by comparing actual changes achieved with those prescribed by ClinCheck^®. The rates of clinically significant inaccuracies (CSI) observed for buccal expansion (≥ 0.5 mm) and buccolingual inclination (≥ 2°) during expansion were then determined. Results: In terms of expansion, the ST1 group demonstrated the highest CSI rate at all tooth levels, whereas the ST2 group had the lowest rate of CSI and the lowest mean inaccuracy for each tooth level. In terms of buccolingual inclination, the ST1 group had the highest CSI rate across all tooth levels, whereas the EX2 group had the lowest CSI rate at all tooth levels except for the canine level where the ST2 group had the lowest CSI rate. A tendency toward overexpression of buccal crown inclination, and underexpression of buccal expansion was observed at all tooth levels. Conclusions: Two-week aligner change regimens offer improved accuracy compared with 1-week aligner changes. SmartTrack^® 2-week changes were the most accurate for buccal expansion, whereas EX30^® 2-week changes were the most accurate for buccolingual inclination.

• The korean journal of orthodontics
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• v.46 no.1
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• pp.13-19
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• 2016

Objective: The aim of this study was to compare the accuracy of Bolton analysis obtained from digital models scanned with the Ortho Insight three-dimensional (3D) laser scanner system to those obtained from cone-beam computed tomography (CBCT) images and traditional plaster models. Methods: CBCT scans and plaster models were obtained from 50 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner; Bolton ratios were calculated with its software. CBCT scans were imported and analyzed using AVIZO software. Plaster models were measured with a digital caliper. Data were analyzed with descriptive statistics and the intraclass correlation coefficient (ICC). Results: Anterior and overall Bolton ratios obtained by the three different modalities exhibited excellent agreement (> 0.970). The mean differences between the scanned digital models and physical models and between the CBCT images and scanned digital models for overall Bolton ratios were $0.41{\pm}0.305%$ and $0.45{\pm}0.456%$, respectively; for anterior Bolton ratios, $0.59{\pm}0.520%$ and $1.01{\pm}0.780%$, respectively. ICC results showed that intraexaminer error reliability was generally excellent (> 0.858 for all three diagnostic modalities), with < 1.45% discrepancy in the Bolton analysis. Conclusions: Laser scanned digital models are highly accurate compared to physical models and CBCT scans for assessing the spatial relationships of dental arches for orthodontic diagnosis.

• The korean journal of orthodontics
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• v.28 no.6 s.71
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• pp.905-914
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• 1998

The goals of this study were to present presurgical naso-alveolar molding (PNAM) appliance in unilateral cleft lip and palate treatment and to evaluate the effects of PNAM appliance on alveolar molding. Samples were consisted of 4 unilateral cleft lip and palate infants (3 males and 1 female, mean age=23.2 days after birth) who were treated with PNAM appliances in Department of Orthodontics, Seoul National University Dental Hospital. Average alveolar cleft gap between the greater and lesser segment was 8.27mm and average duration of alveolar molding treatment was 9.7 weeks. These patients' models were obtained at initial visit (T1) and alter successful alveolar molding (T2). Seven linear and five angular variables were measured by using photometry and digital caliper. All statistical analyses were performed by SPSS win ver. 7.5 program. Paired t-test was used to compare the mean values. 1. The posterior part of alveolar segments are the stable structures during alveolar molding treatment period in infants. 2. Forward growth of the greater segment may be hindered by the action of alveolar molding. 3. The closure of cleft gap during alveolar molding were usually due to inward and backward bending of the anterior part of the greater segment and outward bending of the whole lesser segment.

• The korean journal of orthodontics
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• v.37 no.6
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• pp.400-406
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• 2007

The purpose of this experimental study was to evaluate the effect of immediate orthodontic loading on the stability at the bone-implant interface of titanium miniscrews in a rabbit model. Methods: Forty titanium miniscrews (1.6 mm diameter, 8 mm length) were inserted in the tibiae of 10 rabbits. Twenty test group miniscrews were subjected to continuous orthodontic forces of 200g immediately after implantation for a period of 6 weeks. The remaining 20 control group miniscrews were left unloaded for the same follow-up interval. Removal torque values were recorded using a digital torque gauge. An independent t-test was performed. Results: All the miniscrews were stable, and exhibited no mobility or displacement throughout the experimental period. Histologically, miniscrews were well-integrated into bone. No statistically significant differences in removal torque data were found between the loaded test and the unloaded control groups. Conclusions: These findings suggest that titanium miniscrews can be used as anchoring units for orthodontic tooth movement immediately after insertion.

• The korean journal of orthodontics
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• v.38 no.5
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• pp.328-336
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• 2008

Objective: The purpose of this study was to compare the torque resistance to removal of sandblasted large grit and acid etched (SLA) surface treated orthodontic mini-implants and smooth surface orthodontic mini-implants as well as performing histologic observations. Methods: Two groups of custom screw shaped orthodontic mini-implants (C-implant, 1.8 mm outer diameter $\times$ 9.5 mm length, Cimplant, Seoul, Korea) were designated. 22 SLA treated C-implants (SLA group) and 22 machined surface C-implants (machined group) were placed in the tibia metaphysis of 11 adult New Zealand white rabbits. Following a 6-week healing period, the rabbits were sacrificed. Subsequently, the C-implants were removed under reverse torque rotation with a digital torque measuring device and independent t-test was performed. Selected tissues were prepared for histologic observation. Results: The SLA group presented a higher mean removal torque value (6.286 Ncm) than the machined group (4.491 Ncm) which was statistically significant (p < 0.005). Histologic observation revealed a trend of more new bone formation in contact with the screw surface in the SLA group than the smooth group. Conclusions: The results of this study suggested that SLA surface treatment can enhance the osseintegration potential for C-orthodontic mini-implants.

• The korean journal of orthodontics
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• v.37 no.5
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• pp.351-363
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• 2007

The aim of this study was to evaluate pulp and periodontal changes following rapid tooth retraction by periodontal distraction after bone undermining surgery in young adult dogs. Methods: Alter extraction of second premolars, the interseptal bone mesial to the upper 3rd premolar was undermined. After activating the distraction appliance at 0.5 mm/day for six days, the dogs were sacrificed at 0, 1, 3, 5, 7, and 9 weeks during the consolidation period. Tissue changes of periodontium and pulp were evaluated radiologically, histologically, and immunohistochemically. Results: Digital subtraction radiography showed active bone formation in the stretched periodontal ligament from 0 - 4 weeks. Resorption of the alveolar bone, appearance of osteoclasts, and infiltration of inflammatory cells were observed just after the activation period at the pressure side, and distinctive bone formation was seen in the tension side of the periodontal ligament from 1 week. New bone formation was active at 1 - 3 weeks. The expression of calcitonin gene-related peptide in the experimental group was increased at the alveolar bone and pulp, and periodontal ligament at the pressure side from 0 - 1 week, and it decreased after 5 weeks to become similar to that of the control group. Conclusions: The results showed that rapid tooth movement using periodontal distraction can be new form of orthodontic tooth movement for accelerating normal bone formation.

• The korean journal of orthodontics
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• v.34 no.6 s.107
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• pp.473-480
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• 2004

The aim of this study was to establish normative data on the tooth size and arch parameters of Koreans with normal occlusion, This study employed the dental casts of 296 (male: 179; female 117) normal occlusion samples, who were selected from 15,836 adults through a community dental health survey. The mesiodistal diameters of teeth, arch width, and arch length were measured by digital electronic calipers(accurate to 0.01 mm) and Bolton's indices as well as intermaxillary arch width ratios were calculated. In order to ensure reliability, intra- and inter-examiner error were evaluated. Although our dimensional data showed overt differences between genders, the indices and intermaxillary ratios evaluated were the same. The resultant data obtained were compared with the previous data to reveal whether any changes have occurred over the time. The clinical implication of the present findings was also discussed. This biometric study seemed to provide a clinically applicable diagnostic criteria for an individual malocclusion patient.

• The Journal of the Korean dental association
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• v.52 no.1
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• pp.17-26
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• 2014

Computerized 3D virtual dental models are currently available, and their use has started to improve treatment outcomes. The accuracy of digital models has been demonstrated by many studies and various intra-oral scanners are innovated for short scanning time and high precision. Recently, a digital model was combined with a high technology computer-driven system, which was developed for the application of a digital set-up and indirect bonding of lingual attachments. In this section, virtual treatment planning using a virtual set-up program is be introduced, and the clinical applications and accuracy of computer-generated indirect bonding are discussed.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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• pp.40.1-40.8
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• 2018

Background: A 9-year-old male showed severe defects in midface structures, which resulted in maxillary hypoplasia, ocular hypertelorism, relative mandibular prognathism, and syndactyly. He had been diagnosed as having Apert syndrome and received a surgery of frontal calvaria distraction osteotomy to treat the steep forehead at 6 months old, and a surgery of digital separation to treat severe syndactyly of both hands at 6 years old. Nevertheless, he still showed a turribrachycephalic cranial profile with proptosis, a horizontal groove above supraorbital ridge, and a short nose with bulbous tip. Methods: Fundamental aberrant growth may be associated with the cranial base structure in radiological observation. Results: The Apert syndrome patient had a shorter and thinner nasal septum in panthomogram, PA view, and Waters' view; shorter zygomatico-maxillary width (83.5 mm) in Waters' view; shorter length between the sella and nasion (63.7 mm) on cephalogram; and bigger zygomatic axis angle of the cranial base (118.2°) in basal cranial view than a normal 9-year-old male (94.8 mm, 72.5 mm, 98.1°, respectively). On the other hand, the Apert syndrome patient showed interdigitating calcification of coronal suture similar to that of a normal 30-year-old male in a skull PA view. Conclusion: Taken together, the Apert syndrome patient, 9 years old, showed retarded growth of the anterior cranial base affecting severe midface hypoplasia, which resulted in a hypoplastic nasal septum axis, retruded zygomatic axes, and retarded growth of the maxilla and palate even after frontal calvaria distraction osteotomy 8 years ago. Therefore, it was suggested that the severe midface hypoplasia and dysostotic facial profile of the present Apert syndrome case are closely relevant to the aberrant growth of the anterior cranial base supporting the whole oro-facial and forebrain development.

• Imaging Science in Dentistry
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• v.52 no.1
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• pp.43-51
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• 2022

Purpose: The aim of this study was to evaluate the reliability of the Vectra M3 (3D Imaging System; Canfield Scientific, Parsippany, NJ, USA) in detecting chin asymmetry, and to assess whether the automatic markerless tracking function is reliable compared to manually plotting landmarks. Materials and Methods: Twenty subjects (18 females and 2 males) with a mean age of 42.5±10.5 years were included. Three-dimensional image acquisition was carried out on all subjects with simulated chin deviation in 4 stages (1-4 mm). The images were analyzed by 2 independent observers through manually plotting landmarks and by Vectra software auto-tracking mode. Repeated-measures analysis of variance and the Tukey post-hoc test were performed to evaluate the differences in mean measurements between the 2 operators and the software for measuring chin deviation in 4 stages. The intraclass correlation coefficient (ICC) was calculated to estimate the intra- and inter-examiner reliability. Results: No significant difference was found between the accuracy of manually plotting landmarks between observers 1 and 2 and the auto-tracking mode (P=0.783 and P=0.999, respectively). The mean difference in detecting the degree of deviation according to the stage was <0.5 mm for all landmarks. Conclusion: The auto-tracking mode could be considered as reliable as manually plotted landmarks in detecting small chin deviations with the Vectra^® M3. The effect on the soft tissue when constructing a known dental movement yielded a small overestimation of the soft tissue movement compared to the dental movement (mean value<0.5 mm), which can be considered clinically non-significant.