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 The flexibility of the cylindrical specimen was evaluated at 2 minutes-, 1 hour-, and 24 hours- after being withdrawn from the curing water bath by checking the stress at 10% compression.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 The order of stress from lowest to highest for the 10% compression at 1 hour- and 24 hours- after being withdrawn from the curing water bath was Correct VPS, Examixfine, Provil L C.D., and Express.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.

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.

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.

아크릴릭 레진 수복시 결합면 처리 및 중합상태가 굴곡(屈曲)강도에 미치는 효과

정경천,방몽숙 전남대학교 치과대학 1989 전남치대논문집 Vol.1 No.2

The fracture of acrylic resin dentures is an unresolved problem in removable prosthodontics. This study was aimed to evaluate the repair-rates of the flexure strength, fracture toughness and deflection of repaired acrylic resins. The specimens were divided into 9 groups and tested under 3-point flexure system of U.T.M. The fractured specimens were repaired with heat-cured or cold-cured acrylic resin and re-tested. The following results were obtained, 1. In the heat cured repairs, flexure strength, fracture toughness and deflection were highly increased(P<0.01). 2. The flexure strength of the heat cured repairs was 83% of original strength and that of the cold cured repairs was between 55% and 67%. 3. The groups which have smooth, monomer-pretreated joint surface were increased in the flexure strength, fracture toughness and defletion. 4. The groups which were cured in 37℃ water or 37℃ water under air pressure were increased in the flexure strength, fracture toughness and deflection, but the air-cured groups were decreased.

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.

타액오염이 식각 금속 유지 장치의 레진 접착에 미치는 영향

박하옥,방몽숙 전남대학교 치과대학 1989 전남치대논문집 Vol.1 No.2

The purpose of this study was to evaluate the influence of saliva contamination on the resin bonding of the etched metal retainers. The test sampls were made of Verabond, and divided into 3 groups. Retainers in group 1 had normally etched metal surfaces. Retainers in group 2 had normally etched metal surfaces which were saliva-contaminated for 30 seconds and cleaned wih streaming, luke-warm water for 1 minute and dried thoroughly. Retainers in group 3 had normally etched metal surfaces which were saliva-contaminated for 30 seconds and dried thoroughly without water-cleansing. Each 3 group specimen was watched on SEM. A resin core, 5mm in diameter and 6mm in length, was made of Panavia using Teflon mold on the each specimen. These 3 groups were tested to evaluate shear bond strength, using universal testing machine. The results were as follows : 1. The shear bond strength showed no significant difference between group 1 and group 2 2. The shear bond strength showed significant difference between group 1 and group 3. 3. The shear bond strength showed significant difference between group 2 and group 3. 4. Scanning electron microscope photographs of group 1 and group 2 showed no signs of contamination but of group 3 showed somewhat contaminated.

미백 처리된 치아의 표면처리법이 레진과의 결합에 미치는 영향 : A Confocal Laser Scanning Microscopy Study

최낙준,방몽숙 전남대학교 치의학연구소 2002 구강과학 Vol.14 No.3

The purpose of this study was to estimate the effect of a bleaching agent on tooth surfaces and to evaluate the resin bond strength according to different surface treatments on bleached teeth. To prepare for the experimental samples, first. extracted human third molars were used and the body portions of the crowns were cut into four equal-sized specimens. Next, each specimen was mounted in an plastic bottle with self-cured resin and highly polished to have them reveal the enamel or dentin surfaces. Then, the enamel(E) and dentin(D) specimens were divided into four;1)non-bleached, laser-treated(NBLA) group 2)bleached, laser-treated(BLLA) group 3)non-bleached, acid-treated(NBAC) group and 4)bleached, acid-treated(BLAC)ㅁroup. Here. opalescence®(10% carbamide peroxide) was used for bleaching agent. The treated specimens were observed by confocal laser scanning microscopy and bonded with composite resin for shear bond test. The following results were obtained from this experiment: 1. Compared with the ENB group, the EBL group was shown to be dyed about 20μm deeper with rhodamine B. The DBL group appeared to be caved in at the entry part of the dentinal tubules, was dyed about 20μm deeper and 5μm wider in diameter, compared with the DNB group. 2. In comparison with the EBLAC group. the ENBAC group looked evenly bonded with the resin, while the DNBAC group, compared to DBLAC group. was observed to have its resin tags penetrated about 50μm deeper. Other than those, however, no observable differences between ENBLA and EBLLA group or between DNBLA and DBLLA group were found. 3. At the shear bond test. the ENBAC group was shown to have statistically significant higher shear bond strength than the EBLAC group(p<(0.05). No statlstically significant differences between the ENBLA and the EBLLA groups were observed(f)0.05). 4. At the shear bond test, the DNBAC group was shown to have statistically significant higher shear bond strength than the DBLAC group(p<0.05) No statistically significant differences between the DNBLA and the DBLLA groups were observed(p>0.05). The in vitro observations above suggest that tooth-bleaching procedure brings a certain change on enamel and dentin surfaces and it weakens the shear bond strength with composite resin when the bleached tooth was acid-treated.

레진 시멘트와 상아질 접착제를 사용한 콤포지트 레진 코아의 전단결합강도에 관한 연구

김현오,방몽숙 전남대학교 치의학연구소 2003 구강과학 Vol.15 No.1

The purpose of this study was aimed to compare the shear bond strength on dentin of three dentin bonding agents and two resin cements used in conjunction with self-cured composite resin core material. Control group and six experimental groups were divided for study. Control group was designated as specimens bonded with Tenure A&B^�. And experimental groups were as follows; PB-BL group: specimens bonded with Prime & Bond NT^�, BondLink^� SB-BL group: specimens bonded with SingleBond�, BondLink^� PB group: specimens bonded with Prime & Bond NT^� SB group: specimens bonded with SingleBond^� PF group: specimens bonded with Panavia-F^� Bl group: specimens bonded with Bistite Ⅱ^� All specimens were stored in 37℃ distilled water for 24 hours. followed by the shear bond strength was tested by instron universal testing machine. The data was analysed statistically by Mann-whitney test. The results were as follows : 1. For Prime & Bond NT and SingleBond, the shear bond strength was 0.24 Mpa and 7.19 Mpa each by each, while Tenure A&B group control was measured at 13.93 Mpa (p<0.05). Especially for Prime & Bond NT, it did not get conjunction with dentin. 2. For Prime & Bond NT and SingleBond using BondLink, there was no significant difference as a result of 11.73 Mpa and 14.00 Mpa each by each (p,0.05). 3. For Panavia-F and Bistite Ⅱ, they showed the highest shear bond strength as measured by 18.24 MPa and 16.09 MPa each(p<0.05).

초음파 진동이 주조금관의 변연형태와 시멘트의 결합강도에 미치는 영향

이윤경,방몽숙 전남대학교 치의학연구소 2002 구강과학 Vol.14 No.2

This study was aimed to evaluate the effects of ultrasonic vibration on margin types and cements by comparing bond strength of cemented crown. In this study, margins of each metal die, which were chamfer, shoulder and shoulder with bevel, were prepared using cement. The specimens were divided by the finish line and cement used, ultrasonic vibration. I made total 84 specimens. All specimens were divided into two groups. One group was not vibrated, the other group was subjected to ultrasonic vibration for 12minutes. Tensile bond strength was measured using Universial testing machine. The changes of bond strength in groups were statistically analyzed by t-test or one-way ANOVA. The results were as follows: 1. Ultrasonic instrumentation diminished the bond strength of crown cemented with zinc phosphate cement and resin cement after 12minutes application. 2. In case of zinc phosphate cement, the bond strength of vibrated group was showed significantly decreased(p<0.05). In vibrated groups with zinc phosphate cement, shoulder with bevel exhibit a significant difference to chamfer and shoulder(p<0.05) 3. Resin cement was more resistant to ultrasonic vibration than zinc phosphate cement and showed no significant differences according to ultrasonic vibration and margin type. In conclusion, These results revealed that zinc phosphate cement was most affected and resin cement was the least affected by ultrasonic vibration. Especially shoulder with bevel design was most affected in zinc phosphate cement groups, we should consider these results and be taken in the application of ultrasonic vibration to any teeth restored with crowns.