• The Journal of Korean Academy of Prosthodontics
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• v.29 no.3
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• pp.55-74
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• 1991

The purpose of this study was to investigate the influence of early functional load around osseointegrated titanium implants. 24 titanium plasma spray coated implants (ITI HS-type) were placed into the previously extracted site in the mandible of six adult dogs. The implants were divided into three groups : the control group was the implants without abutment during the experimental period; the experimental group I was loaded by connecting the contoured abutment after 6 weeks of healing; the experimental group II was loaded after 12 weeks of healing: and the mandibular second premolar and surrounding tissues were selected for natural tooth group to compare the implanted group. All dogs were injected intravenously tetracycline, alizarin red S, and calcein for bone labeling. After the experimental period of 18 weeks, the dogs were sacrificed and longitudinal sections of the bone-implant interface were cut and observed using light microscope, scanning electron microscope, and fluorescence microscope. The results of the study were as follows: 1. Light and scanning electron microscopically, all implant surfaces were well contact with bone tissue at the cortical layer, but some areas of cancellous bone were not contact directly. 2. Fluorescence microscopically, number and size of the new secondary osteons around the implant were increased than those of the natural tooth. 3. Fluorescence microscopically, linear and concentrical fluorescence was observed at or near the surface of all implants, and the bone formation and remodeling of the implants loaded after 6 week of healing were great, and unloaded implants were worst. 4. Fluorescence microscopically, endosteal bone formation was greater than periosteal bone formation at or near the implants. 5. Fluorescence microscopically, number and size of linear and concentric fluorescence was increased at the lingual side than the buccal side of the loaded implants. The result of the study indicate the possibility of the early load to the implant via a prosthesis.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.1
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• pp.150-165
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• 1998

For the purpose of evaluating the effect of both direct retainer design and bony absorption degree around abutment of indirect retainer on the supporting tissue of abutment of indirect retainer, dislodging force was transmitted to unilateral distal extension RPD bases. Analysis of stress distributed within the supporting tissue around abutment of indirect retainer was carried out. Using three-dimensional photoelastic stress analysis method and the conclusion is a follows. 1. According to the extent of force which the direct retainer of the most distal abutment tooth, the amount of force transmitted to the abutment tooth of indirect retainer was small. 2. Of all the cases, Mandibular first premolar which was used abutment tooth of indirect retainer, buccal, mesial and distal sides represented compression stress and lingual side represented tensile stress. 3. The more bone resorption of abutment tooth of indirect retainer, the more distortion of buccal and distal side of abutment tooth was existed and the extent of compression stress which was existed and distal side to abutment tooth was large. 4. When the alveolar bone around the abutment with indircet retainer is normal. The amount of force transmitted on abutment with indirect retainer was small in the order of Akers clasp, RPA clasp, RPI clasp. 5. When the alveolar bone around the abutment with indirect retainer has been absorbed 20% and 30%, the amount of force transmitted on abutment with indirect retainer was small in the order of RPA calsp, RPI clasp, Akers clasp. 6. When denture is displaced, shape of the direct retainer reciprocating abutment affect much the function of indirect retainer.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.3
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• pp.186-199
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• 2012

Purpose: Single implants, of which screw loosening has been observed frequently, presents problems such as fixtures fractures, marginal bone loss, and inflammation of the soft tissue around the implant. However, the single implant is more conservative, cost effective, and predictable compared to the 3 unit bridge with respect to the long-term outcome. This study evaluated the survival rate as well as future methods aimed at increasing the survival rate in single implants in posterior teeth. Methods: Among the implants placed in the Dankook University Dental Hospital department of Oral & Maxillofacial surgery from January 2001 to June 2008, 599 implants placed in the maxillar and mandibular posterior were evaluated retrospectively. Survival rates were investigated according to implant location, cause of tooth loss, gender, age, general disease, fixture diameter and length, surface texture, implant type and shape, presence of bone graft, surgery stage, surgeons, bone quality and opposite teeth. Results: Out of 599 single implants in posterior teeth, 580 implants survived and the survival rate was 96.8%. The difference in survival rate was statistically significant according to the implant location. The survival rate was low (84.2%) in implants exhibiting a wide diameter (${\geq}5.1mm$) and the surface treated by the acid etching group demonstrated a significantly lower survival rate (91.1%). One stage surgical procedure, which implemented a relatively better bone quality survival rate (100%), was higher than the two stage surgical procedure (96.1%). The survival rate of type IV bone quality (75%) was significantly lower than the other bone quality. Conclusion: Single posterior teeth implant treatments should use an improved surface finishing fixture as well as careful and safe procedures when performing implant surgery in the maxilla premolar and molar regions since bone quality is poor.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.1
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• pp.37-42
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• 2010

Purpose: The mental foramen (MF) is an important anatomical structure during local anesthesia and surgical procedures in terms of achieving effective mental nerve blocks and avoiding injuries to the neurovascular bundles. Thus, understanding the anatomic features of the mandibular canal and accessory mental foramen in Korean could contribute to the surgical anatomic assessment. This study was to elucidate frequency, position and course of AMF (accessory mental foramen) in Korean using 3D cone beam computed tomography. Materials and Methods: The CBCT (Conbeam computed tomography) DICOM data (Alphard, Asahi, Japan) from 540 patients in korean were analyzed. We investigated images of 3D CBCT using Ondemand (CyberMed, Korea) software program on the incidence and anatomical characteristics of accessory foramen. Results: The accessory mental foramina were found in 17 patients. Accessory mental foramina exist predominantly in the apical area of the second premolar and posteroinferior area of the mental foramen. The accessory branches of the mandibular canal showed common characteristics in the course of gently sloping posterosuperior direction in the buccal surface area. The size of most AMF was obviously smaller than that of MF. Conclusion: We could identify frequency, position and course of AMF (accessory mental foramen) by the anatomical study of the accessory mental foramen using 3D cone beam CT in Korean.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.4
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• pp.260-264
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• 2013

Calcium hydroxide root canal filing paste (vitapex) is widely used as canal filling paste for infected canal. However, chemical burn is possible because of the high alkali base of calcium hydroxide. A 57-year old woman was admitted to our clinic for consistent dull pain and paresthesia in the left upper lip, zygoma and buccal cheek area, which developed during an endodontic treatment of the left lateral incisor. Radiographic finding showed radiopaque material, which exits from the left incisor root apex, and was within the left canine and first premolar buccal soft tissue. The overfilled Vitapex extended to the soft tissue was surgically curetted. The result of the surgical curettage was favorable. Though slight hypoesthesia on the upper lip was still remained, paresthesia on zygomatic and buccal cheek area was completely recovered. As far as we know, this is the first case report of infraorbital nerve damage from overfilled Vitapex material.

• The korean journal of orthodontics
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• v.44 no.5
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• pp.236-245
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• 2014

Objective: To evaluate the therapeutic effects of a preformed assembly of nickel-titanium (NiTi) and stainless steel (SS) archwires (preformed C-wire) combined with temporary skeletal anchorage devices (TSADs) as the sole source of anchorage and to compare these effects with those of a SS version of C-wire (conventional C-wire) for en-masse retraction. Methods: Thirty-one adult female patients with skeletal Class I or II dentoalveolar protrusion, mild-to-moderate anterior crowding (3.0-6.0 mm), and stable Class I posterior occlusion were divided into conventional (n = 15) and preformed (n = 16) C-wire groups. All subjects underwent first premolar extractions and en-masse retraction with preadjusted edgewise anterior brackets, the assigned C-wire, and maxillary C-tubes or C-implants; bonded mesh-tube appliances were used in the mandibular dentition. Differences in pretreatment and post-retraction measurements of skeletal, dental, and soft-tissue cephalometric variables were statistically analyzed. Results: Both groups showed full retraction of the maxillary anterior teeth by controlled tipping and space closure without altered posterior occlusion. However, the preformed C-wire group had a shorter retraction period (by 3.2 months). Furthermore, the maxillary molars in this group showed no significant mesialization, mesial tipping, or extrusion; some mesialization and mesial tipping occurred in the conventional C-wire group. Conclusions: Preformed C-wires combined with maxillary TSADs enable simultaneous leveling and space closure from the beginning of the treatment without maxillary posterior bonding. This allows for faster treatment of dentoalveolar protrusion without unwanted side effects, when compared with conventional C-wire, evidencing its clinical expediency.

• The korean journal of orthodontics
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• v.47 no.5
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• pp.313-322
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• 2017

Objective: Miniscrew-assisted rapid palatal expansion (MARPE) is a means for expanding the basal bone without surgical intervention in young adults. Here, we assessed the differences in dental, alveolar, and skeletal measurements taken before (T0), immediately after (T1), and 1 year after (T2) MARPE. Methods: Twenty-four patients (mean age, 21.6 years) who had undergone MARPE and cone-beam computed tomography at T0, T1, and T2 were included. Changes in the following parameters were compared using paired t-tests: intercusp, interapex, alveolar, nasal floor, and nasal cavity widths; inclination of the first molar (M1) and its alveolus; and thickness and height of the alveolar bone. A linear mixed-effects model was used to determine variables that affected periodontal changes in the M1. Results: MARPE produced significant increases in most measurements during T0-T2, despite relapse of some measurements during T1-T2. The alveolar thickness decreased on the buccal side, but increased on the palatal side. The alveolar crest level at the first premolar moved apically. Changes in the thickness and height of the alveolar bone were affected by the corresponding initial values. Conclusions: MARPE can be used as an effective tool for correcting maxillomandibular transverse discrepancy, showing stable outcomes 1 year after expansion.

• Journal of Oral Medicine and Pain
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• v.13 no.1
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• pp.13-21
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• 1988

The author studied the vertical height of tooth crown and the amounts of alveolar bone resorption with age. All 84 subjects(44 male, 40female) who visited Dental hospital of Wonkwang University with no history of sever periodontal disease and no experience of periodontal surgery. 84 subject were divided into 3 groups by age, that is, group I(28-32yrs), group II(38-42yrs), and group III(48-52yrs). Informal radiogram with bite wing film(horizontal angulation : $0^{\circ}$, vertical angulation : $+5^{\circ}~+10^{\circ}$) were taken on premolar and molar area. The distances from cusp tip to cementoenamel junction (vertical height of tooth crown) and from cementoenamel junction alveolar crest(amount of alveolar bone resorption) were measured, and then recorded data from 946 teeth were statistically analysed. This study was undertaken to obtain the data for age estimation by the changes of tooth crown height and alveolar bone resorption in the point of forensic odontology. The obtained results were as follows : 1. The average crown height of mandibular right 1st. molar was 7.1mm in group I, 6.7mm in group II, and 6.6mm group III, and the average amount of alveolar bone resorption on mandibular right 1st. molar were 1.8mm in group I, 2.5mm in group II, and 3.0mm in group III. Ratio of tooth crown height to amount of alveolar bone resorption was 4.0:1 in groupI, 2.7:1 in group II, and 2.2:1 in group III, the ratio was decreased with age. 2. In comparison with upper teeth and lower teeth in ipsilateral side, the average value of tooth crown height and amount of alveolar bone resorption were slightly higher in upper arch than those in lower arch, but there was not a statistically significant difference. 3. The ratio of height of tooth crown to amount of alveolar bone resorption was decreased with age, and which depended mainly upon the change of amount of alveolar bone resorption rather than the change of tooth crown height.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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• pp.271-278
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• 1987

The purpose of the present study was to investigate associations between periapical and bitewing techniques by assessing the crestal alveolar bone. This article also reports the ability of these two techniques to correctly detect evidence of interproximal dental caries, and comparison between the interproximal overlapping of teeth. Bitewing and periapical radiographs were used from posterior quardants of 243 dental students in Seoul National University. The distance from cemento-enamel junction to the alveolar crest (CEJ-AC) was measured for each proximal surface from the distal of cuspid to the distal of second molar. Data were arranged according to the proximal surface examined, and bitewing and periapical measurements were compared using paired tests. The obtained results were as follows: 1. In maxilla, a significant t ratio with a P value of 0.05 or less reached for 100% and in mandible, reached for 94%. 2. The anatomic limitations imposed on periapical radiographic technique, most often result in somewhat foreshortened radiographic images. This situation would tend to be accentuated by the anatomical restrictions of the hard palate. 3. Consequently, since the significant differences frequently exist between measurements obtained from bitewing and periapical techniques, it is important to define which technique is used. 4. The number of the interproximal overlapping was the largest medial side of the maxillary second molar, while the smallest at the distal side of the mandibular second premolar. And the overall number of the interproximal overlapping was more (538) in the periapical technique than in the bitewing technique (372). 5. The interproximal dental carious lesions were detected more (74) on the bitewing films than on the periapical ones (23). The fact was resulted from the small number of interproximal overlapping and relative easi- ness of obtaining horizontal angulation in taking the bitewing radiographs.

• Imaging Science in Dentistry
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• v.41 no.2
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• pp.71-78
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• 2011

Purpose : This study was performed to determine the optimal tile size for the fractal dimension of the mandibular trabecular bone using a tile counting method. Materials and Methods : Digital intraoral radiographic images were obtained at the mandibular angle, molar, premolar, and incisor regions of 29 human dry mandibles. After preprocessing, the parameters representing morphometric characteristics of the trabecular bone were calculated. The fractal dimensions of the processed images were analyzed in various tile sizes by the tile counting method. Results : The optimal range of tile size was 0.132 mm to 0.396 mm for the fractal dimension using the tile counting method. The sizes were closely related to the morphometric parameters. Conclusion : The fractal dimension of mandibular trabecular bone, as calculated with the tile counting method, can be best characterized with a range of tile sizes from 0.132 to 0.396 mm.