• The korean journal of orthodontics
• /
• v.51 no.2
• /
• pp.105-114
• /
• 2021

Objective: The purpose of this study was to evaluate the relationship between rotational disk displacement (DD) of the temporomandibular joint (TMJ) and the dentoskeletal morphology. Methods: Women aged > 17 years were included in this study. Each subject had a primary complaint of malocclusion and underwent routine cephalometric examinations. They were divided into five groups according to the findings on sagittal and coronal magnetic resonance images of their TMJs: bilateral normal disk position, bilateral anterior DD with reduction (ADDR), bilateral rotational DD with reduction (RDDR), bilateral anterior DD without reduction (ADDNR), and bilateral rotational DD without reduction (RDDNR). Twenty-three cephalometric variables were analyzed, and the Kruskal-Wallis test was used to evaluate differences in the dentoskeletal morphology among the five groups. Results: Patients with TMJ DD exhibited a hyperdivergent pattern with a retrognathic mandible, unlike those with a normal disk position. These specific skeletal characteristics were more severe in patients exhibiting DD without reduction than in those with reduction, regardless of the presence of rotational DD. Rotational DD significantly influenced horizontal and vertical skeletal patterns only in the stage of DD with reduction, and the mandible exhibited a more backward position and rotation in patients with RDDR than in those with ADDR. However, there were no significant dentoskeletal differences between ADDNR and RDDNR. Conclusions: The results of this study suggest that rotational DD of TMJ plays an important role in the dentoskeletal morphology, particularly in patients showing DD with reduction.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.28 no.3
• /
• pp.222-228
• /
• 2006

Various methods have been used in the past to indirectly analyze the craniofacial region. Among these, the lateral and posterior-anterior cephalometircs are used for the evaluation of the dentofacial deformities. However, cephalometircs create inaccuracies because of the inherent enlargement and distortion of the image. The interpretation of cephalometric films is also problematic: the number of anatomic landmarks that can be identified accurately is limited, and the overlap of structures on a radiograph making locating these landmarks difficult. To overcome these problems, computed tomography(CT) has been recommended as an useful modality in the diagnosis, surgical planning, and follow-up of craniofacial anomalies. There is no significant enlargement or distortion of the image, overlap of structure, or tracing error. And the number of anatomic landmarks is vast. The purpose of this study was to examine the orbit and midfacial region using Occlusal Maxillary CT, consisted of slices parallel to the occlusal plane. Based on these CT scan, we provide the data that could be applied to monitor an individual patient's skeletal pattern and the guide to the maxillary osteotomy.

• The korean journal of orthodontics
• /
• v.28 no.4 s.69
• /
• pp.581-589
• /
• 1998

In order to correct a maxillofacial-skeletal disharmony successfully and achieve a favorable facial profile, orthodontic treatment must begin at pubertal growth spurt. Therefore predicting the pubertal growth pattern and evaluating the growth potential is very important. For an orthodontist, estimating skeletal maturity in relation to one's personal growth spurt is essential and it must be considered into the treatment. The objective of this study was to find out whether there was a difference in menacheal age among different malocclusion groups and to evaluate the skeletal maturity at menarche. The subjects were 64 Class I malocclusion patients, 51 Class II patients and 38 Class III patients. Skeletal maturity was estimated from handwrist radiographs of these patients. Handwrist radiographs were taken between 3 months before and after the menarche. The results were as follows. 1. The mean chronologic age of menarche was $12.50{\pm}1.01$ years. 2. For the Class I malocclusion group the mean age of menarche was $12.36{\pm}1.04$ years, for Class II $12.81{\pm}1.03$ years and for Class III $12.32{\pm}0.82$ years. According to these results Class II malocclusion patients started mensturation later than Class I and Class III malocclusion patients. 3. No difference was found considering the skeletal maturity at menarche among the malocclusion groups. 4. The skeletal maturity index at menarche was SMI 7 for $45.10\%$, SMI 8 for $27.25\%$, SMI 9 for $10.46\%$, SMI 6 for $7.84\%$, SMI 10 for $7.84\%$ and SMI 5 for $1.31\%$ patients. 5. Statistically there was a significant correlation between skeletal maturity estimated by handwrist radiographs and menacheal age(p<0.05, r=0.25430).

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.34 no.3
• /
• pp.250-265
• /
• 2008

Distraction osteogenesis is a well-established clinical treatment for limb length discrepancy and skeletal deformities. Appropriate mechanical tension-stress is believed not to break the callus but rather to stimulate osteogenesis. In contrast to fracture healing, the mode of bone formation in distraction osteogenesis is primarily intramembranous ossification. Although the biomechanical, histological, and ultrastructural changes associated with distraction osteogenesis have been widely described, the basic biology of the process is still not well known. Moreover, the molecular mechanisms in distraction osteogenesis remain largely unclear. Recent studies have implicated the growth factor cascade is likely to play an important role in distraction. And current reserch suggested that mechanical tension-stress modulates cell shape and phenotype, and stimulates the expression of the mRNA for bone matrix proteins. The purpose of this study is to examine the pattern of expression of growth factors($TGF-{\beta}1$, IGF-I, bFGF) and extracellular matrix proteins(osteoclacin, osteonectin) related to osteogenesis by osteodistraction of the mandible in rabbits. 24 rabbits is used for this experiment. Experimental group are gradual distraction(0.7mm, twice/day), acute distraction(1.4mm, twice/day) and control group is only osteotomized. After 5 days latency, osteotomic site is distracted for each 7 days and 3.5 days. Consolidation period is 28 days. The animal is sacrificed at the 3th, 7th, 14th, 28th. The distracted bone is examined by immunohistochemical analysis and RT-PCR analysis. The results obtained from this study were as follow : No significant difference was found on clinical examination according to distraction rate, but gradual distraction was shown to improve regenerate bone formation on radiographic and histologic examination. Growth factors and extracelluar matrix proteins expression increased in distraction group than control group. From these results, it could be stated that graudal distraction is shown to improve and accelerate bone formation and mechanical stress like distraction has considerable effects on osteogenesis related factors. And rabbit is the most appropriate animal model for further reseach on the molecular mechanisms that mediate osteodistraction. It is believed that understanding the biomolecular mechanisms that mediate distraction osteogenesis may guide the development of targeted strategies designed to improve distraction osteogenesis and accelerate bone healing.

• The korean journal of orthodontics
• /
• v.27 no.1
• /
• pp.1-20
• /
• 1997

Skeletal Class III malocclusions are growth-related discrepancies, and the problems are more severe until growth is complete. Causes of skeletal Class III malocclusion are classified into mandibular overgrowth, maxillary deficiency, and combination of the two. Face mask has been recommended for treatment of Class III malocclusion with maxillary deficiency in the early time of growth. Numerous experiments were performed and clinical studies have been reported on face mask ; nevertheless, studies on profile changes and stability after treatment of face mask are considered to be somewhat insufficient. The author selected 50 patients who can be checked for follow-up. They had been diagnosed as skeletal Class III malocclusion with maxillary deficiency and then treated with face mask ; the sample group was divided according to sex, treatment beginning age, palatal suture opening (intraoral appliance). For each group, changing pattern of facial profile and stability of treatment observed, and comparison with 20 Korean normal children(Angle's Class I). The following results were obtained. 1. skeletal, dental, and soft tissue measurements indicated more changes in the amounts of maxillary forward movement during face mask treatment. 2. R.P.E. group showed more significant maxillofacial changes and La-Li group showed more dental changes. 3. Growth changes of maxilla induced in the treatment group during wearing face mask were much more than those of normal group. 4. Growth changes of maxilla in the treatment group after treatment of face mask were less than those of normal group. From the obtained aata, it can be concluded that there was a stimulative effect on forward growth of maxilla during the use of face mask ; however, on removal of face mask, the stimulative effect was eliminated and undergrowth tendency of maxilla resumed.

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

• The Journal of Korea Assosiation for Disability and Oral Health
• /
• v.6 no.2
• /
• pp.94-98
• /
• 2010

Axenfeld-Rieger syndrome is a rare autosomal dominant disorder characterized by various ocular and extraocular malformations. The incidence of Axenfeld-Rieger syndrome has been estimated to be 1 per 200,000. The syndrome is characterized by short body stature, delayed bone age, and deficient or arrested development of neural crest cells involving the anterior chamber of the eyes, facial bones, teeth, periumbilical skin, and cardiovascular system. This is a case of a 6 year-old girl, who came to the department of the pediatric dentistry, Yonsei University Dental Hospital, for evaluation and treatment of multiple congenital missing permanent teeth. The patient presented typical dental, craniofacial, and systemic features of Axenfeld-Rieger syndrome, such as glaucoma, oval pupil, heterochromatic iris, umbilical hernia, and delayed bone age. On the panoramic view, 3 primary teeth were missing and 13 permanent tooth germs were absent. On the lateral cephalograph, underdevelopment of the maxilla and normal growth pattern of the mandible were confirmed. Periodic dental follow-up is planned for evaluation and interceptive treatment of her dental and craniofacial problems. Denture or removable space maintainer with a pontic is considered for esthetic and functional restoration. In addition, orthognathic surgery is also planned in future to prevent further midfacial skeletal deformation. Early diagnosis of Axenfeld-Rieger syndrome is very important to prevent exacerbation of complications, such as glaucoma and skeletal deformities.