• Imaging Science in Dentistry
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• v.43 no.4
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• pp.227-233
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• 2013

Purpose: This study was performed to analyze human maxillary and mandibular trabecular bone using the data acquired from micro-computed tomography (micro-CT), and to characterize the site-specific microstructures of trabeculae. Materials and Methods: Sixty-nine cylindrical bone specimens were prepared from the mandible and maxilla. They were divided into 5 groups by region: the anterior maxilla, posterior maxilla, anterior mandible, posterior mandible, and mandibular condyle. After the specimens were scanned using a micro-CT system, three-dimensional microstructural parameters such as the percent bone volume, bone specific surface, trabecular thickness, trabecular separation, trabecular number, structure model index, and degrees of anisotropy were analyzed. Results: Among the regions other than the condylar area, the anterior mandibular region showed the highest trabecular thickness and the lowest value for the bone specific surface. On the other hand, the posterior maxilla region showed the lowest trabecular thickness and the highest value for the bone specific surface. The degree of anisotropy was lowest at the anterior mandible. The condyle showed thinner trabeculae with a more anisotropic arrangement than the other mandibular regions. Conclusion: There were microstructural differences between the regions of the maxilla and mandible. These results suggested that different mechanisms of external force might exist at each site.

• Imaging Science in Dentistry
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• v.31 no.3
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• pp.165-173
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• 2001

Objectives : To evaluate the absorbed and effective doses of spiral and computed tomography for the dental implant planning. Materials and Methods: For radiographic projection, TLD chips were placed in 22 sites of humanoid phantom to record the exposure to skin and the mean absorbed dose to bone marrow, thyroid, pituitary, parotid and submandibular glands and nesophagus. Effective dose was calculated, using the method suggested by Frederiksen et al.. Patient situations of a single tooth gap in upper and lower midline region, edentulous maxilla and mandible were simulated for spiral tomography. 35 axial slices (maxilla) and 40 axial slices (mandible) with low and standard dose setting were used for computed tomography. All the radiographic procedures were repeated three times. Results: The mean effective dose in case of maxilla was 0.865 mSv, 0.452 mSv, 0.136 mSv and 0.025 mSv, in spiral tomography of complete edentulous maxilla, computed tomography with standard mAs, computed tomography with low mAs and spiral tomography of a single tooth gap (p<0.05). That in case of mandible was 0.614 mSv, 0.448 mSv, 0.137 mSv and 0.036 mSv, in spiral tomography of complete edentulous mandible, computed tomography with standard mAs, computed tomography with low mAs and spiral tomography of a single tooth gap (p<0.05). Conclusions: Based on these results, it can be concluded that low mAs computed tomography is recommended instead of spiral tomography for the complete edentulous maxilla and mandible dental implant treatment planning.

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.2
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• pp.235-248
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• 1994

There were many studies that distribute the partial edentulous states and examine the removable partial denture designs in the planning of removable partial denture treatment. This study was performed in the point of removable partial denture prescription to evaluate partial edentulism and its removable partial denture designs. The data was collected from the dental laboratory of each three dental colleges in Seoul and from two dental laboratories only for removable partial dentures as a prescription form. A total of 1411 cases with prescription form collected from dental laboratories were distributed for this study, then 788 cases were selected for this study. The case selection was done according to the contents of prescription form. The selected cases were divided into maxillary arch and mandibular and classified in terms of types of major connector and direct retainer, unbroken anterior teeth, Kennedy classification, the number of remaining teeth, and distribution of age and sex. The analyzed results were as follows : 1. The Kennedy classification I showed highest frequency both in maxilla and mandible. 2. The arch distribution of removable partial denture was 50.08% for maxilla and 49.92% for mandible. 3. The highest frequency in the distribution of direct retainer was the RPA clasp design. 4. The frequency of unbroken anterior 6 was 73.36% for maxilla and 82.30% for mandible. 5. The design of broad palatal strap and lingual bar revealed the highest prevalence in the major connector construction. 6. The mean number of remaining teeth per arch was 8.25 for maxilla and 8.37 for mandible. 7. The mean age of the patients supplied with removable partial denture was 52.25 years for men, 51.68 years for women, 52.11 years for maxilla, and 51.76 years for mandible and women showed more prevalence.

• Journal of Korean society of Dental Hygiene
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• v.20 no.1
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• pp.11-18
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• 2020

Objectives: We analyzed the correlation between physique and size of the dental arch of college students with normal occlusion. Methods: Ninety-nine college students filled out the prepared questionnaire. The length and width of the dental arch of the students was measured using a plaster model after taking an impression. The data were analyzed using the t-test and correlational analysis. Results: The maxilla arch length was 3.70 mm longer and the inter-molar width of the maxilla was 3.06 mm longer in men (both p<0.01) than in women. Additionally, the mandible was 3.66 mm longer in men as compared to those in the women (p<0.01). As height increased, there was increase in the body weight (α=0.683, p<0.01), maxilla arch length (α=0.373, p<0.01), molar width of the maxilla (α=0.214, p<0.05), and the mandible (α=0.280, p<0.01). The greater the weight increase, the greater the maxillary arch length increase (α=0.392, p<0.01), and the greater the molar width of the maxilla (α=0.336, p<0.01) and mandible (α=0.502, p<0.01) increase. Conclusions: As physical size (both height and weight) increased, the maxillary length and molar width also increased. Based on the results of this study, the cause of malocclusion, form and size of the dental arch, and stable occlusion can be used as basic data.

• Journal of Periodontal and Implant Science
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• v.28 no.3
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• pp.517-523
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• 1998

The purpose of this study was to investigate the width of attached gingiva of young adults with healthy gingiva. We compared the differences according to the tooth location. The width of attached gingiva of maxilla and mandible was measured by histochemical method. The results were as follows: 1. The width of buccal keratinized gingiva in maxilla was widest in incisors(5.2-5.6mm) and narrowest in first bicuspids(4.4-4.5mm). 2. The width of buccal keratinized gingiva in mandible was widest in incisors(4.3-4.5mm) and narrowest in first bicuspids(3.2-3.3mm). 3. The width of lingual keratinized gingiva in mandible was widest in first molars(5.5-5.6mm) and narrowest in incisors(2.9-3.0mm). 4. The width of buccal attached gingiva in maxilla was widest in incisors(4.1-4.4mm) and narrowest in molars (3.0mm). 5. The width of buccal attached gingiva in mandible was widest in incisors(3.2-3.4mm) and narrowest in second molars (1.7-1.8mm). 6. The width of lingual attached gingiva in mandible was widest in first molars(3.5-3.7mm) and narrowest in incisors(1.9-2.1mm).

• Imaging Science in Dentistry
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• v.36 no.3
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• pp.157-162
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• 2006

Familial gigantiform cementoma is a rare fibre-cemento-osseous disease of the jaws which appears to be transmitted as an autosomal dominant trait with variable expressivity of the phenotype. A 7-year-old girl visited DKUDH complaining of the painless facial deformity. Clinically, significant facio-lingual expansion was observed at the left maxilla, left mandibular body and symphysis portion. Malposition of lower anterior teeth was found. Panoramic radiograph and CT scan showed the extensive expansile mixed lesion at maxilla and mandible. Bone scan revealed hot spot at the maxilla and left side of mandible. Histologic examination revealed moderately dense fibrous connective tissue with scattered masses resembling cementum. The patient's mother had a history of the mandibular resection due to benign tumor. Her younger brother had buccal expansion of right mandible. We report our finding of a family that has exhibited clinical, radiographic and histologic findings consistent with the familial gigantiform cementoma.

• Journal of the korean academy of Pediatric Dentistry
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• v.10 no.1
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• pp.123-129
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• 1983

This study was designed to find out the prevalence d the fused teeth in the primary dentition and their successors. The clinical and panoramic radiographic examination was undertaken of 5226 children (male 2812, female 2414) attended department of Pedodontics, College of Dentistry, Yon Sei University, Seoul, Korea. The results were as follows; 1. The prevalence of the fused teeth in the primary dentition was 1.03 percent and female (1.2%) affected more frequently than male (0.89%). 2. Compare with the maxilla and mandible, the prevalence of the fused teeth were higher in the mandible than in the maxilla. 3. The fusion of the primary teeth were occured between central with lateral incisor in the maxilla, and central with lateral and lateral with canine in the mandible. 4. There were 33 cases (61%) of succeding teeth missing among 54 case of the rused teeth.

• The korean journal of orthodontics
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• v.24 no.2
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• pp.349-366
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• 1994

The method of treatment in skeletal Class III malocclusion must be chosen according to an etiology and timing of the treatment. Maxillry protraction has been used as an effective treatment method in growing children with maxillary deficiency. The efficacy of maxillary protraction has been viewed as a result of downward-backward displacement of mandible and compensatory dental displacement during the treatment rather than forward -downward growth of maxilla itself. In this study, 104 subjects treated with maxllary protraction, and 19 males and 21 females with known annual growth amount have been chosen longitudinally as treated group and normal group, respectively. And changes in position of maxilla, mandible and dentition have been comparatively analyzed on the lateral cephalometric radiographs by age. The results were as follows : 1. Treated group showed more forward movement of maxilla compare to the normal group and the mandible displaced backward compare to the normal group. 2. Downward movement of maxilla in treated group was similar to that of normal group with statistical signigicance in female 12 year old group and downward movement of mandible in treated group was similar to that of normal group. 3. In treated group, maxillary central incisor moved more forward than the normal group with statistical significance in male 8, 10 year-old groups and female 8, 9, 10 year-old groups. In treated group, downward movement of maxillary central incisor was similar to that of the normal group with statistical significance in male and female 7,8 year-old groups. Considering the above results and the duration of the treatment, the forward movement of maxilla due to maxillary protraction was effective compared to normal growth amount of the normal group.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.1
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• pp.105-108
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• 2000

Odontogenic myxoma is one of rare tumors in oral and maxillofacial region and it is thought to be mesenchymal or ectomesenchymal origin. Its characteristics are benign and non-metastatic but it has the potential of local invasion and high recurrence rate. It originally occurs in atrium of heart and in central case, my xoma is located mainly in the maxilla and mandible. Most odontogenic myxoma develops in 2nd or 3rd decades of life and rarely occurs in child or older persons over fifty. The distribution of reported cases between the sexes is similar and the maxilla and mandible are equally affected or slightly higher in mandible. Clinically it is usually asymptomatic, however it can cause pain and paresthesia is complained in the advanced stages. Displacement and mobility of teeth have also been reported. Odontogenic myxoma is not a frequent tumor, but in case of slow and painless growing tumor it must be considered as a differential diagnosis.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.17 no.2
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• pp.180-185
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• 1995

TMJ ankylosis is classified with true and false type. A true ankylosis is defined as any condition that produces fibrous or bony adhesions between the articular surfaces of the temporomandibular joint. The main causes of true ankylosis are trauma or infection. A false ankylosis results from pathologic conditions outside the joint that limit mobility of the mandible such as myogenic disorders, coronoid impingement or rare direct bony fusion between maxilla and mandible. The treatment of choice of TMJ ankylosis is surgical intervention. We experienced the male patient with complete mouth opening limitation since 45 years before. This patient has true TMJ ankylosis and rare bony synostosis between maxilla and mandible in the right posterior region. We performed surgical intervention and had a favorable result.