• Archives of Plastic Surgery
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• v.36 no.5
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• pp.531-537
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• 2009

Purpose: Alveolar bone grafting has become an essential process in the treatmemt of alveolar cleft patient for stabilization of the maxillary arch, elimination of oronasal fistula, the reconstruction of the soft tissue nasal base support, and creation of bony support for tooth eruption for implant. The use of Autologous iliac cancellous bone is preferable because of the adequate quantity and high osteoinductive potential. However, even with iliac bone, insufficient osteoregeneration and absorption occur due to several factors such as the patient's age, cleft width, functional stress, and others. In order to increase osteoregeneration where the iliac bone is placed, the present study is associated with bone marrow aspirate (BMA). The experimental study evaluated the efficacy of osteoregeneration in normal cleft rabbits when alveolar bone grafting was performed with autologous iliac corticocancellous bone. Methods: Twenty - four New Zealand White rabbits were divided randomly into 2 groups (BMA, control). All animals underwent harvesting of corticocancellous bone graft from the right posterior iliac crest via standard surgical technique. $1m{\ell}$ of BMA were obtained by scraping the needle and aspirate with $10m{\ell}$ syringe from the contralateral iliac bone wall. The muco - periosteal flap on the palate was elevated. A mixture of Equal bone's volumes with BMA and saline as its control was inserted into the cleft. Animals were sacrificed at 2, 4, and 8 weeks and maxilla was harvested for dental peri - apical X-ray, bone matrix density (BMD),and histologic analysis. Result: BMD of regenerated bone to the cleft in the rabbits was higher than that of the control rabbits. X-ray, histologic analysis showed that increased osteoregeneration and low absorption rate were observed in the BMA group. Conclusion: Our experimental study showed BMA enhanced the osteoregeneration and survival rate of alveolar bone grafting. BMA is easy to extract & cost - time effective. So it can be an effective enhancers for bone grafting mixtures.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.1
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• pp.14-24
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• 2022

The aim of the present study is to evaluate the validity of orthodontic measurements including tooth width, Bolton ratio, overjet and overbite on the digital dental models. Dental models of the subjects aged 12 to 18 were obtained in 3 different forms, which were conventional stone model, digital model created with Freedom HD model scanner, and digital model produced with CS3600 intraoral scanner. After measurements were made on the models, reliability and reproducibility of the measurements were evaluated by using intraclass correlation coefficient, while validity was assessed with paired t-test. As a result, significant reliability and reproducibility were verified, with intraclass correlation coefficient exceeding 0.750 in all groups. Measurements of the model scanned group showed an adequate validity in overall and anterior Bolton ratio, overjet, and overbite. Intraoral scanned models showed an adequate validity in anterior Bolton ratio, and overjet. Measurement on intraoral scanned digital models can be considered as an alternative for young children who have difficulty in taking impression. Furthermore, careful considerations on measurement error should be made in clinical situations.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.4
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• pp.276-284
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• 2023

After tooth extraction, alveolar bone is resorbed over time. Loss of alveolar bone and reduction of upper soft tissue poses difficulties in future implant placement and long-term survival of the implant. This case report focuses on increasing the soft and hard tissues at the implant placement site by using alveolar ridge augmentation and a xenogeneic collagen matrix as a soft tissue substitute in an extraction socket affected by periodontal disease. In each case, the width of the alveolar bone increased to 6 mm, 8 mm, and 4 mm, and regeneration of the interdental papilla around the implant was shown, as well as buccal keratinized gingiva of 4 mm, 6 mm, and 4 mm, respectively. Enlarged alveolar bone facilitates implant surgery, and interdental papillae and keratinized gingiva enable aesthetic prosthesis. This study performed alveolar ridge augmentation on patients with extraction sockets affected by periodontal disease and additionally used soft tissue substitutes to provide a better environment for implant placement and have positive effects for aesthetic and predictive implant surgery.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.553-563
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• 2000

Horseshoe Expander is one of Slow Maxillary Expansion(SME) which aims to accommodate the contra- lateral expansion and midpalatal suture expansion or the palate. The appliance consists of skeleton type strew embedded in split Horseshoe appliance. It is the objectives of the presentation to manifest the changes in dental & craniofacial components subsequent to the application of Horseshoe Expander. The subjects for this study consisted of 32 patients (mean age : 12.7). frontal, lateral cephalometric headfilm were taken and study casts were fabricated before and after expansion. 24 items were measured, compared preexpansion with postexpansion. Especially, palatal volume was measured by means of 'Hydro-measurement method'. Tooth axis measurement on the dental casts were made with Universal bevel protractor, and Horseshoe Expander group were compared with RME group. This study of changes to maxillary expansion with Horseshoe Expander revealed the following significant results. 1. Triangular-shaped expansion pattern appeared in frontal cephalometric headfilm. 2. Palatal plane, occlusal plane, mandibular plane and upper incisor to FH increased in lateral cephalometrir headfilm. 3. Palatal volume increased significantly. A slight bite opening, reduction of occlusal contact points showed in dental casts. 4. A 2.2:1 ratio of the amount of intermolar width in maxilla(orthodontic movement) to maxillary width (orthopedic movement) was determined. 5. Horseshoe Expander group has less buccal tipping tendency than RME group, by taking high correlation coefficients in the upper second premolar and first molar. It was suggested that Horseshoe Expander showed less orthodontic changes, less buccal tipping tendency. In addition, it was effective in maxillary expansion.

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.1
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• pp.37-46
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• 1994

The purpose of this study was to evaluate the effect of various cements on the retention of casting crown and the cement film thickness. To evaluate the retention of crown, thirty maxillary premolars were used and prepared to largely same dimension. According to the routine method, Non-precious metal crowns were made. The teeth and the metal crowns were divided into three groups and cemented under 5kg static pressure. Group I was composed of 10 teeth and 10 metal crowns and was cemented with zinc phohsphste cement. Group II was composed of 10 teeth and 10 metal crowns and was cemented with Panavia-EX cement. Group III was composed of 10 teeth and 10 metal crowns and was cemented with All-Bond & composite resin cement. After 5 days, the cemented specimens were mounted and the failure loads were measured by an Instron Universal Testing Machine. To evaluate the cement film thickness. 5 metal teeth and 5metal crowns from a prepared maxillary premolar were made. Two marks were flawed on the margin part of each surface at 4-surfaces of each specimen(one mark : crown, the other : metal tooth) and were measured the width with SEM photograph(80 sheets) before and after cementation(Panavia-EX, All-Bond cement, & ZPC) was made. Differences of the widths of marks between before and after were measured, and differences from 4-surfaces of a specimen cemented with a cement were measured and calculated. The results were as follows ; 1. There was a statistically significant difference between the failure loads of group III and the others(p<0.05). 2. There was a statistically significant difference between the cement film thickness of group III and the others(p<0.05).

• Journal of Periodontal and Implant Science
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• v.23 no.3
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• pp.577-594
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• 1993

The ultimate goal of periodontal therapy is the regeneration of the periodontium that have been destroyed as a result of periodontal disease. This study were done in order to determine the healing status of periodontium under Polytetrafluoroethylene and millipore fillter combined with fibrin and the effect of the guided tissue regeneration procedures were performed as follows : 1) flap operation using PTFE membrane(control group) 2) flap operation using PTFE membrane which was fixed with fibrin(experimental group 1) 3) flap operation using millipore filter which was fixed with suture(experimental group II) 4) flap operation using millipore filter which was fixed with fibrin(experimental group II) After 1, 2, 4, 8, 12 weeks, dogs were sacrificed by perfusion technique and tissue block was excised including the tooth and prepared for light microscope with H-E & Masson’s trichrome staining. The result were as follows : In control and experimental group, there is no siginificant difference on epithelial cell down growth within 1st week, but more epithelial cell downgrowth in millipore or millipore combined with fibrin group. In this experiment, there were no significant difference in new cementum and alveolar bone formation whether PTFE membrane was fixed with suture or fibrin. In control and each experimental group, bone maturation appeared in 4 weeks, bone width increased bucco-lingually in control and experimental 1 group especially. Both control group and experimental group showed mild mew cementum formation on root surface and irregular arrangement of collagen fiber at 4 weeks, that showed obvious increased cementum formation at 8 weeks, and that was observed the functional arrangement of collagen fiber between new cementum and new alveolar bone at 12 weeks.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.191-198
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• 2009

Statement of problem: Ceramics have been important materials for the restoration of teeth. The demands of patients for tooth-colored restorations and the availability of various dental ceramics has driven the increased use of new types of dental ceramic materials. Improved physical properties of theses materials have expanded its use even in posterior crowns and fixed partial dentures. However, ceramic still has limitation such as low loading capability. This is critical for long-span bridge, because bridge is more subject to tensile force. Purpose: The wire reinforced ceramic was designed to increase the fracture resistance of ceramic restoration. The purpose of this study was to evaluate the fracture resistance of wire reinforced ceramic. Material and methods: Heat pressed ceramic(ingot No.200 : IPS Empress 2, Ivoclar Vivadent, Liechtenstein) and Ni-Cr wire(Alfa Aesar, Johnson Matthey Company, USA) of 0.41 mm diameter were used in this study. Five groups of twelve uniform sized ceramic specimens(width 4 mm, thickness 2 mm, length 15 mm) were fabricated. Each group had different wire arrangement. Wireless ceramic was used as control group. The experimental groups were divided according to wire number and position. One, two and three strands of wires were positioned on the longitudinal axis of specimen. In another experimental group, three strands of wires positioned on the longitudinal axis and five strands of wires positioned on the transverse axis. Three-point bending test was done with universal testing machine(Z020, Zwick, Germany) to compare the flexural modulus, flexural strength, strain at fracture and fracture toughness of each group. Fractured ceramic specimens were cross-sectioned with caborundum disc and grinded with sandpaper to observe interface between ceramic and Ni-Cr wire. The interface between ceramic and Ni-Cr wire was analyzed with scanning electron microscope(JSM-6360, JEOL, Japan) under platinum coating. Results: The results obtained were as follows: 1. The average and standard deviation in flexural modulus, flexural strength and fracture toughness showed no statistical differences between control and experimental groups. However, strain was significantly increased in wire inserted ceramics(P<.001). 2. Control group showed wedge fracture aspects across specimen, while experimental groups showed cracks across specimen. 3. Scanning electron microscopic image of cross-sectioned and longitudinally-sectioned specimens showed no gap at the interface between ceramic and Ni-Cr wire. Conclusion: The results of this study showed that wire inserted ceramics have a high strain characteristic. However, wire inserted ceramics was not enough to use at posterior area of mouth in relation to flexural modulus and flexural strength. Therefore, we need further studies.

• Restorative Dentistry and Endodontics
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• v.30 no.1
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• pp.38-48
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• 2005

The purpose of this study was to compare and evaluate the shaping ability of the three different Ni-Ti file systems used by undergraduate students. Fifty undergraduate students prepared 150 simulated curved root canals in resin blocks with three Ni-Ti file systems - $ProFile^{(R)}$ (PF), Manual $ProTaper^{(R)}$ (MPT), Rotary $ProTaper^{(R)}$ (RPT). Every student prepared 3 simulated root canals with each system respectively. After root canal preparation, the Ni-Ti files were evaluated for distortion or breakage Assessments were made according to the presence of various types of canal aberrations. The pre- and post-instrumented canal images were attained and superimposed. The instrumented root canal width were measured and calculated for the net transportation (deviation) and the centering ratio. Under the condition of this study, both $ProTaper^{(R)}$ systems allowed significantly more removal of root canal wall than the $ProFile^{(R)}$ system. In the important other aspects such as the centering ratio, there was no significant differences between the systems. Novice dental students were able to prepare curved root canals with any kinds of Ni-Ti file systems with little aberration and great conservation of tooth structure. Students want to learn effective methods and at the same time simple rotary procedures. The rotary $ProTaper^{(R)}$ systems were one of the most compatible to these students from the point of view of cutting ability The $ProFile^{(R)}$ system was also compatible in safe and gentle shaping.