• The korean journal of orthodontics
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• v.47 no.1
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• pp.31-38
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• 2017

Objective: This study aimed to quantitatively assess the relationship of smile esthetic variables with various types of malocclusion, and identify the cephalometric factors affecting smile measurements. Methods: This retrospective study included 106 patients who were treated with retention at the orthodontic department of Taipei Medical University Hospital. Hard-tissue variables were measured using lateral cephalographic tracings, and nine smile esthetic variables were measured using facial photographs. The patients were divided into three groups according to their overjet (< 0, 0-4, and > 4 mm). An analysis of variance was conducted to compare the pretreatment cephalometric variables and smile esthetic variables among the three groups. Multiple linear regression analysis was performed to identify the cephalometric factors affecting the smile measurements in each group. Results: Except the upper midline and buccal corridor ratio, all of the smile measurements differed significantly among the three groups before orthodontic treatment. Some of the smile characteristics were correlated with the cephalometric measurements in different types of malocclusion. The overjet was the major factor influencing the smile pattern in all three types of malocclusion. Conclusions: Smile characteristics differ between different types of malocclusion; the smile may be influenced by skeletal pattern, dental procumbency, or facial type. These findings indicate that establishment of an optimal horizontal anterior teeth relationship is the key to improving the smile characteristics in different types of malocclusion.

• Journal of Oral Medicine and Pain
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• v.22 no.1
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• pp.81-94
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• 1997

The Purpose of this study were to examine the epidemiology of snoring, its associated factors and anatomic features on cephalogram according to the frequency of snoring in young adults. Epidemiological survey using questionaire was made to the 438 students (320 male, 118 female) aged 19 - 28 years, and cephalometric study of anatomic features on 14 habitual snorers, 31 occasional snorers and 30 non-snorers among men was done. The obtained results were as follows : 1. The prevalence snoring was 11.4% in the young adults, 15.0% in male and 1.7% female. 2. Of the young adults, 3.7% were habitual snorers and 7.8% were occasional snorers. 3. Smoking and drinking increased the frequency of snoring(p < 0.01), but didn't affec the differences in the frequency between habitual and occasional snoring. 4. No significant correlation was made between the frequency of snoring and the factors such as overweight, nasal disease and hypertension. 5. In the cephalometric comparison between snorers and non-snorers, snorers had inferiorly positioned hyoid bone(p < 0.05), longer soft palate(p < 0.01), steeper soft palate(p < 0.05) and narrower nasopharyngeal(p < 0.05) and oropharyngeal(p < 0.001) airway. 6. In the cephalometric comparison between habitual snorers and occasional snorers, habitual snorers had narrow nasopharyngeal airway(p < 0.05).

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.4
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• pp.168-174
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• 2013

Objectives: The aim of this study is to investigate the correlation between 2-dimensional (2D) cephalometric measurement and 3-dimensional (3D) cone beam computed tomography (CBCT) measurement, and to evaluate the availability of 3D analysis for asymmetry patients. Materials and Methods: A total of Twenty-seven patients were evaluated for facial asymmetry by photograph and cephalometric radiograph, and CBCT. The 14 measurements values were evaluated and those for 2D and 3D were compared. The patients were classified into two groups. Patients in group 1 were evaluated for symmetry in the middle 1/3 of the face and asymmetry in the lower 1/3 of the face, and those in group 2 for asymmetry of both the middle and lower 1/3 of the face. Results: In group 1, significant differences were observed in nine values out of 14 values. Values included three from anteroposterior cephalometric radiograph measurement values (cant and both body height) and six from lateral cephalometric radiographs (both ramus length, both lateral ramal inclination, and both gonial angles). In group 2, comparison between 2D and 3D showed significant difference in 10 factors. Values included four from anteroposterior cephalometric radiograph measurement values (both maxillary height, both body height) and six from lateral cephalometric radiographs (both ramus length, both lateral ramal inclination, and both gonial angles). Conclusion: Information from 2D analysis was inaccurate in several measurements. Therefore, in asymmetry patients, 3D analysis is useful in diagnosis of asymmetry.

• Journal of Oral Medicine and Pain
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• v.24 no.2
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• pp.189-206
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• 1999

This study was performed to investigate the factors affecting muscle activity and cephalometric variables according to change of head postures. For this study, 150 patients with temporomandibular disorders and 80 dental students without any signs and symptoms of temporomandibular disorders were selected as the patients group and as the normal group, respectively. Head position to body-midline in frontal plane and upper quarter posture to body plumb line in sagittal plane were observed clinically and electromyographic(EMG) activity of anterior temporalis, masseter, sternocleidomastoideus, and trapezius on clenching were recorded with $BioEMG^{(R)}$ in four head postures, which were natural head posture(NHP), forward head posture(FHP), $20^{\circ}$ upward head posture(UHP), and $20^{\circ}$ downward head posture(DHP). Cephaloradiographs were also taken in the same head postures as in EMG taking, but that was taken only in NHP for the patient group. Cephalometric variables measured were SN angle, CVT angle, atlas inclination angle, occlusal plane angle, Me-C2 angle, pharyngeal width, occiput~axis distance, area of pharyngeal space, and cervical curvature. The data were analyzed by SAS statistical program. The results of this study were as follows : 1. Between the patient and the normal group, there were significant difference in distance from plumb line to acromion, eye-tragus angle, electromyographic activity of the four muscles, and cephalometric variables of linear measurement. 2. There was no consistent pattern of correlation between upper quarter posture, EMG activity and cephalometric variables in any case without relation to cervical curvature and head position in frontal plane. 3. Sternocleidomastoid muscle only showed variation of electromyographic activty with changes of head postures, but all the muscles did show correlation with head postures. 4. All the cephalometric variables measured in this study showed difference of mean value by head posture, and CVT angle, pharyngeal width, occiput-atlas distance, and area of pharyngeal space showed correlation between these variables with change from NHP to FHP, and from NHP to UHP.

• The korean journal of orthodontics
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• v.45 no.6
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• pp.308-321
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• 2015

Objective: The efficacy of mandibular advancement devices (MADs) in the treatment of obstructive sleep apnea (OSA) ranges between 42% and 65%. However, it is still unclear which predictive factors can be used to select suitable patients for MAD treatment. This study aimed to systematically review the literature on the predictive value of cephalometric analysis for MAD treatment outcomes in adult OSA patients. Methods: The MEDLINE, Google Scholar, Scopus, and Cochrane Library databases were searched through December 2014. Reference lists from the retrieved publications were also examined. English language studies published in international peer-reviewed journals concerning the predictive value of cephalometric analysis for MAD treatment outcome were considered for inclusion. Two review authors independently assessed eligibility, extracted data, and ascertained the quality of the studies. Results: Fifteen eligible studies were identified. Most of the skeletal, dental, and soft tissue cephalometric measurements examined were widely recognized as not prognostic for MAD treatment outcome; however, controversial and limited data were found on the predictive role of certain cephalometric measurements including cranial base angle, mandibular plane angle, hyoid to mandibular plane distance, posterior nasal spine to soft-palate tip distance, anterior nasal spine to epiglottis base distance, and tongue/oral cross sectional area ratio thus justifying additional studies on these parameters. Conclusions: Currently available evidence is inadequate for identification of cephalometric parameters capable of reliably discriminating between poor and good responders to MAD treatment. To guide further research, methodological weaknesses of the currently available studies were highlighted and possible reasons for their discordant results were analyzed.

• The Journal of the Korean dental association
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• v.53 no.8
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• pp.558-568
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• 2015

Objective: The objectives of this study were to measure pediatric organ and effective doses of cone-beam computed tomography (CBCT) for orthodontic analysis and to compare them to those of panoramic and lateral cephalometric radiography, the conventional radiography for orthodontic analysis. Materials and Methods: Alphard VEGA for CBCT, Planmeca Proline XC for panoramic radiography and Orthophos CD for cephalometric radiography were used for this study. Thermoluminescent dosimeter (TLD) chips were located at 24 anatomic sites of 10-year-old anthropomorphic phantom and exposed during CBCT (C-mode; $200{\times}179mm$ FOV), panoramic and lateral cephalometric radiographic procedures at the clinical exposure settings for 10-year-old patient. Pediatric organ and effective doses were measured and calculated using ICRP 2007 tissue weighting factors. Results: Effective doses of CBCT, panoramic radiography and lateral cephlometric radiography in pediatric clinical exposure settings were $292.5{\mu}Sv$, $19.3{\mu}Sv$, and $4.4{\mu}Sv$ respectively. The thyroid gland contributed most significantly to the effective dose in all the radiographic procedures. Conclusion: Effective dose of CBCT was about 12 times to conventional radiographic procedures for orthodontic analysis in pediatric patient. The use of CBCT for orthodontic analysis should be fully justified over conventional radiography and dose optimization to decrease thyroid dose is needed in pediatric patients.

• Imaging Science in Dentistry
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• v.41 no.1
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• pp.17-21
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• 2011

Purpose : The purpose of this study was to examine the patient- and treatment-related etiologic factors of external root resorption. Materials and Methods : This study consisted of 163 patients who had completed orthodontic treatments and taken the pre- and post-treatment panoramic and lateral cephalometric radiographs. The length of tooth was measured from the tooth apex to the incisal edge or cusp tip on the panoramic radiograph. Overbite and overjet were measured from the pre- and post-treatment lateral cephalometric radiographs. The root resorption of each tooth and the factors of malocclusion were analyzed with an analysis of variance. A paired t test was performed to compare the mean amount of root resorption between male and female, between extraction and non-extraction cases, and between surgery and non-surgery groups. Correlation coefficients were measured to assess the relationship between the amount of root resorption and the age in which the orthodontic treatment started, the degree of changes in overbite and overjet, and the duration of treatment. Results : Maxillary central incisor was the most resorbed tooth, followed by the maxillary lateral incisor, the mandibular central incisor, and the mandibular lateral incisor. The history of tooth extraction was significantly associated with the root resorption. The duration of orthodontic treatment was positively correlated with the amount of root resorption. Conclusion : These findings show that orthodontic treatment should be carefully performed in patients who need the treatment for a long period and with a pre-treatment extraction of teeth.

• The korean journal of orthodontics
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• v.41 no.3
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• pp.164-173
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• 2011

Objective: The purpose of this study was to perform gender-wise analysis of the related cephalometric factors affecting Korean patients with obstructive sleep apnea (OSA). Methods: We examined 118 adults who had visited the Sleep Disorder Clinic Center in Keimyung university, Daegu, Korea, and evaluated them by using poly-somnography (PSG) and lateral cephalograms. The patients were divided into 4 groups (male simple snorers, male OSA patients, female simple snorers, and female OSA patients) according to AHI (apnea-hypopnea index) and sex. Results: The position of the hyoid bone in the female OSA group was inferior to that in the female simple snorer group. Multiple regression analysis showed that tongue length and soft palate width were significant determinants for the severity of AHI in male OSA patients. However, inferior position of the hyoid was a significant determinant only in women. Conclusions: From a cephalometric point of view, OSA in male and female adult patients may be characterized by different pathogeneses. In particular, in female OSA patients, they might be managed by individualized treatments such as hormone replacement therapy in addition to conventional treatment.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.3
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• pp.161-166
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• 2013

Purpose: This study was intended to perform a cephalometric comparison between the patients with and without obstructive sleep apnea (OSA). The factors influencing the OSA in the lateral cephalogram were also investigated. Methods: Fifty patients who had visited the Sleep Disorder Clinic at the Ajou University Hospital and evaluated with the polysomnograph (PSG) and cephalogram, were included in the study. The patients had the apnea-hypopnea episode over 5 times per hour (apnea-hypopnea index $[AHI]{\geq}5$) were diagnosed as OSA after the overnight PSG. To evaluate the hard and soft tissue profiles, the cephalometric radiograms were taken at the maximal intercuspation. The correlation between the patient's age, height, weight, body mass index (BMI) and AHI was inspected in the OSA and control group. The difference between the OSA and control group was evaluated (Mann-Whitney U Test). The cephalometric influencing factors to OSA were analyzed (Pearson's correlation coefficient) statistically using SPSS statistics. Results: The OSA Group had a significantly higher BMI than the control group. The mean lower facial height (ANS-Me) was longer in the OSA group; however, statistically significant difference was not detected in the anteroposterior craniofacial measurements. The distance between mandibular plane and hyoid bone of the OSA group was significantly longer than that of the control group. The hyoid position (MP-Hyoid) had a positive correlation between AHI (P<0.001). However, the measurements of oropharyngeal airway were not different between the two groups. The hypothesis, that the antero-posteriorly narrow oropharyngeal airway may aggravate the airway resistance and give rise to a higher AHI, was rejected in the study. Conclusion: We suggest that the lateral cephalogram may be utilized as a useful method to evaluate OSA. The patients with a lower hyoid position can be expected to have higher risks of OSA. However, a comprehensive intraoral inspection, including the soft palate and tonsilar hypertrophy, is emphasized, as the lateral cepahlogram cannot visualize the oropharyngeal status completely.

• Journal of Yeungnam Medical Science
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• v.18 no.2
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• pp.208-214
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• 2001

Background: When we make treatment plan of class III malocclusion children, it is difficult to determine whether we treat it with orthognathic surgery or without orthognathic surgery. To determine that, we must consider many factors, such as cephalometric analysis, growth pattern, family history, and skeletal age. A Harvold cephalometric analysis is useful in determining the amount of discrepancy by comparing the maxillary unit length with mandibular, unit length. We tried this study to help the decision of treatment planning in class ill malocclusion children by comparison in class III malocclusion and normal occlusion children using a Harvold analysis. Materials and Methods: The materials for this study consisted of 20 class III malocclusion children. Cephalometric tracing and measurements were performed by one investigator. The control group consisted of 18 normal occlusion children and lateral cephalograms were obtained from 8.5 to 14.5 years old children biannually. The relationships between class III malocclusion group and normal occlusion group were evaluated statistically. Results: The lower anterior facial heights between two groups were not significantly different, although the lower anterior facial heights of class III malocclusion group was higher than those of normal occlusion group in all age groups. The Maxillary-mandibular unit length differences of class III malocclusion group were significantly higher than those of normal occlusion group(p<0.05). Conclusion: A Harvold analysis was useful to make treatment planning for class III malocclusion children.