자동혼합 부가중합형 실리콘고무인상재의 인장강도 및 유연성에 관한 연구

방몽숙,신미숙,박영준 大韓齒科器材學會 1995 대한치과재료학회지 Vol.22 No.1

The purpose of this study was to investigate the tensile strength and flexibility of four automixing additional silicone rubber impression materials. To evaluate the tear resistance of impression material, the automixed impression material was cured in a 32℃ water bath with the necked specimen preparation mold for 5 minutes. Three minutes after the withdrawl from the water bath the specimens were tested for their maximum tensile strength with universal testing machine(Instron 4302, England). To evaluate the flexibility of the impression materials, the cylindrical specimen was compress 10% of the original length, and the stress produced by that compression was evaluated. The flexibility of the cylindrical specimen was evaluated at 2 minutes-, 1 hour-, and 24 hours- after being withdrawn from the curing water bath by checking the stress at 10% compression. The results were as follows; 1. Examixfine showed the highest tensile strength value at 18.11 ㎏/㎠ followed by Provil L C.D. at 16.77 ㎏/㎠. The next was Express at 12.40 ㎏/㎠ and Correct VPS showed a significantly low value at 9.62 ㎏/㎠ when compared with other groups(P<0.01). 2. Under the 10% compression, Correct VPS showed significantly low stress at 1.511 ㎏/㎠ when compared with other groups(P<0.01). The other groups were Examixfine at 1.879 ㎏/㎠, Provil at 2.025 ㎏/㎠, and Express showed significantly higher stress at 3.689 ㎏/㎠(P<0.01). 3. The order of stress from lowest to highest for the 10% compression at 1 hour- and 24 hours- after being withdrawn from the curing water bath was Correct VPS, Examixfine, Provil L C.D., and Express. In all experimental groups the stress for dimensional shortening increased as the elapsed time increased.

미사리 출토 토기의 과학적 분석(Ⅱ)

崔夢龍,姜炯台,申叔靜 동아대학교 1992 考古歷史學志 Vol.8 No.-

齒科診療補助人力의 業務에 關한 硏究

方蒙淑 全南大醫大 1984 전남의대학술지 Vol.21 No.1

유한요소법을 이용한 수종 심미수복물의 응력 분석

조진희,방몽숙 전남대학교 치과대학 1990 전남치대논문집 Vol.2 No.1

The purpose of this study was to analyze the stresses and displacements of various esthetic restorations and abutment teeth. The finite element models of central incisor were divided into four groups according to the types of restoration. Three load cases were applied ; 1) 45 degrees on the incisal edge, 2) horizontal force on the labial surface, and 3) 26 degrees diagonally on the lingual surface. Material property, geometry, and load conditions of each model were inputed to the two dimensional finite element program and stresses and displacements were analyzed. Results were as follows ; 1. In the cases of porcelain fused gold crown and porcelain laminate veneer, stresses were equally distributed in supporting abutment tooth. The metal coping of porcelain fused gold crown and collarless porcelain fused gold crown functioned as a good stress distributor. 3. When the horizontal load applied, the highest tensile and compressive stresses were seen in the cervical margin of restoration and the dentin of the abutment tooth. 4. The highest displacement of restoration was seen when load was applied at an angle of 26 degrees diagonally in lingual surface of tooth in centric occlusion. 5. The influence of loading direction on the stresses and displacements in the restoration was greater than that of various design. 6. The possibility of fracture was highest in porcelain jacket crown.

지대치 형태에 따른 Post core의 치근내부 및 지지조직의 응력분석

김진,방몽숙 전남대학교 치과대학 1992 전남치대논문집 Vol.4 No.1

The Purpose of this study was to analyze the stresses and displacements of various post and core. The Finite element models of central incisors were divided into seven types according to the various amount of remaining tooth structures. 10kgf/㎟ force was applied respectively as follows: 1) Horizontal on the labial surface 2) 26˚ diagonal direction on the lingual surface Material property, geometry, and load condition of each model were inputted to the two dimensional ANSYS 4.4A finite element program ; stresses and displacements were analyzed. Results were as follows: 1. In the case of 130˚ shoulder post and core, Maximum tensile and shear stresses were observed in the crown margin. 2. Maximum shear stress was about 29% reduced by contrabevel. 3. In the case of 1㎜ axial tooth structure, Maximum tensile stress observed in the dentin. 4. In the case of butt joint of cervix, Maximum stress concentration was observed in the dentin by the inclined and horizontal force. 5. Horizontal force produced the extraordinary high stresses in dentin and supporting structures. 6. The amount of remaining tooth structure affected the level of stress significantly and it determined the location of stress concentration.

골유착성 임플랜트를 중간지대치로 사용한 고정성 보철물의 응력분석

박상수,방몽숙 전남대학교 치과대학 1992 전남치대논문집 Vol.4 No.1

The purpose of this study was to analyze the stress distribution of the natural teeth, the implant, the prosthesis and the supporting tissue according to the types of implant and connection modality in the five-unit fixed partial denture with a implant pier abutment. A Two dimensional stress analysis model was constructed to represent a mandible missing the first and second premolars and first molar. The model contained a canine and second molar as abutment teeth and implant pier abutments with and without stress-absorbing element. Finite element models were created and analyzed using software ANSYS 4.4A for IBM 32bit personal computer. The results obtained were as follows; 1. Implant group, compared to the natural teeth group, showed a maximum principal stress at the superior portion of implants and a stress concentration at the neck and end portion. 2. Maximum principal stress and maximum Von Mises stress were always lower in the case of rigid connection than nonrigid connection. 3. A cylinder type implant with stress absorbing element and screw type implant were generally similar in the stress distribution pattern. 4. A screw type implant, compared to the cylinder type implant, showed a relatively higher stress concentration at both neck and end portion of it. 5. Load B cases showed higher stress concentration on the posterior abutments in the case of nonrigid connector than rigid connector. 6. A maximum displacement was always lower in the case of rigid connection than nonrigid connection. These results suggest that osseointegrated implant can be used as an intermediate abutment.

파절된 도재전장관의 표면처리 방법에 따른 수복 레진의 접합강도에 관한 연구

정애리,방몽숙 전남대학교 치과대학 1990 전남치대논문집 Vol.2 No.1

The purpose of this study was to evaluate the effect of surface treatment of fractured metal-ceramic crown on bond strength of porcelain repair resin. The specimens were divided into two groups for metal specimens and five groups for porcelain specimens by surface treatment methods. The metal specimens were treated by 2 methods. : micro-sandblasting with 50㎛ aluminum oxide and grinding with diamond bur. The porcelain specimens were treated by 5 methods. : micro-sandblasting with 50㎛ aluminum oxide, grinding with diamond bur, etching with porcelain etching agent, combination of micro-sandblasting and etching procedure, and combination of grinding and etching procedure. After surface treatment, each specimen was bonded with composite resin and the bond strength was measured and the surface texture was observed by scanning electromicroscope(SEM). The results were as follows : 1. There was significant difference in shear bond strength between metal specimen and porcelain specimen. 2. Bond strength of metal specimens treated with coe diamond bur was higher than that treated with 50㎛ alumium oxide sandblasting. 3. Bond strength of porcelain specimen treated with diamond bur was higher than that treated with 50㎛ aluminum oxide sandblasting and porcelain etching agent. 4. There was no significant difference in shear bond strength between the group treated with diamond bur and combined treatment groups respectively. 5. The large undercuts were observed in group treated with diamond bur by SEM.

Overdenture의 지대치 Coping 형태에 따른 광탄성 응력 분석

양혜령,방몽숙 전남대학교 치과대학 1990 전남치대논문집 Vol.2 No.1

This study was executed to analyze the stress distribution of tooth, supporting structure and overdenture by two-dimensional photoelastics when 6 types of coping were inserted. Types of coping were designed to be inclined plane, short dome, medium dome, short square, medium square and o-p anchor attachment. Forces were applied respectively as follows : 1) Vertical load of 12kg on the incisal edge 2) 30˚diagonal load of 8kg on the labial surface. The results were as follows ; 1. In case of short dome and o-p anchor attachment, the stress is evenly distributed on teeth, supporting tissue structure under vertical and 30˚diagonal load, then short dome and o-p anchor attachment show better stress distribution and stabilization of overdenture than any other copings. 2. Inclined plane revealed greater tendency of displacement of overdenture than any other coping under labial diagonal load. 3. Long height of copings had greater concentration of stress than short height of copings. 4. In case of medium dome under labial diagonal load, there were high level of stress concentration on denture base contacted labioincisal angle of coping.

임플란트 고정체와 지대주 연결 형태의 차이에 따른 유지 나사 안정성에 대한 연구

양재식,방몽숙 전남대학교 치의학연구소 2003 구강과학 Vol.15 No.3

Since the concept of osseointegrated dental implant by Branemark et al was first applied to mandibular full edentulous patients. Recently it is considerated the first treatment option on missing teeth. A common problem associated with dental implant restorations is loosening of screws that retain the prosthesis to the abutment and the abutment to the implant fixture. This study is to examine the influence on screw loosening of implant-abutment designs such as external hex, cone screw, beveled hex, cam cylinder, cylinder hex by means of evaluating the loosening torques, with respect to a range of tightening torques after repeated loading. The results of this study were as follows. (1) Cone screw, beveled hex groups are the highest initial tightening rate and cylinder hex, external hex groups are the lowest initial tightening rate(p<0.05). (2) Cone screw groups are the highest after repeated loading tightening rate and cylinder hex groups are lowest after repeated loading tightening rate(p<0.05). (3) Cone screw groups have the highest initial stability and final stability. (4) All groups are decreased tightening rate after repeated loading.

고무 인상재의 크기 안정성 및 친수성에 관한 연구

강충희,방몽숙 전남대학교 치과대학 1991 전남치대논문집 Vol.3 No.1

The purpose of this study was to evaluate the dimensional stability and wettability of several rubber impression materials. Impressions were made from a metal master die machined to simulate five full veneer crown preparations symmetrically placed in an arch form. Casts from impressions were measured about intrapreparation distance, lower base diameter and height of the abutment. For comparing the wettability, specimens from various viscosities of the impression materials were formed against a smooth surface. The contact angle of a saturated aqueous solution of CaSO_4 on the impression materials was measured after 1 minute. Mean contact angle were calculated and results were analyzed. Results obtained were as follows ; 1. As the intrapreparation distance, hydrophilic addition-cured silicone had the smallest change (0.002(0.006%)~0.046(0.230%)mm) and condensation-cured silicone had the largest one (0.030(0.089%)~0.057(0.291%)mm). 2. As the lower base diameter, hydrophobic addition-curedsilicone had the smallest change and polyether had the largest one. 3. As the height, hydrophobic addition-cured silicone had the smallest change and polyether had the largest one. 4. As the contact angle, polyether had the smallest change and condensation-cured silicone had the largest one. Above results suggested that hydrophobic or hydrophilic addition-cured silicone was suited for dimensional stability, polyether or hydrophilic addition-cured silicone for impression of subgingival and wetted areas in clinical dentistry.