백서 고속핵 미각영역에서 gamma-aminobutyric acid의 효과

박하옥,방몽숙 전남대학교 치과대학 1999 전남치대논문집 Vol.11 No.1

Gamma-aminobutyric acid (GABA) is known as an inhibitory neurotransmitter in the neurons of the central nervous system. However, its detailed action mechanisms in the rostral gustatory zone of the nucleus tractus solitarius (rNTS) have not been established. The present study was aimed to investigate the distribution, role and action mechanisms of GABA in rNTS. Presence of GABA ergic neurons was examined by immunohistochemistry and membrane potentials were recorded by whole cell recordings in isolated brain slices of the rat medulla. GABA-containing neurons were present in the gustatory nucleus tractus solitarius. Superfusion of GABA resulted in a concentration-dependent reduction in input resistance in the neurons in rNTS. The change in input resistance was accompanied by membrane hyperpolarization. The spontaneous activity and action potential elicited in response to a depolarizing pulse were diminished by GABA. Superfusion of the slices with either GABA_A agonist, muscimol, GABA_B agonist, baclofen or GABA_C agonist, TACA, decreased input resistance and reduced the nerve activity in association with membrane hyperpolarization. It is suggested that inhibitory signals play a role in sensory processing by the rNTS, in that GABA actions occur through activation of GABA_A, GABA_B, and GABA_C receptors. These results suggest that GABA has an inhibitory effect on the rNTS through an activation of GABA_A, GABA_B, and GABA_C receptors and that the GABAergic inhibition probably plays an important role in sensory processing by the rNTS.

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.

금속 유지장치의 오염이 레진 접착 결합력에 미치는 영향

박하옥(Ha-Ok Park),방몽숙(Mong-Sook Bang) 대한턱관절교합학회 2002 구강회복응용과학지 Vol.18 No.3

도재라미네이트에 사용되는 수종의 레진시멘트와 try-in paste의 색조 비교

안경희,박하옥,방몽숙,양홍서,박상원,An, Kyung-Hee,Park, Ha-Ok,Vang, Mong-Sook,Yang, Hong-So,Park, Sang-Won 대한치과보철학회 2006 대한치과보철학회지 Vol.44 No.5

Statement of problem: The color change of final restoration resulting from resin cement is variable since the amount of the tooth is prepared is minimum. Purpose: The purpose of this study was to compare the color accuracy of try-in paste and their corresponding resin cements and the color stability of restoration intermediated resin cement according to two shades of three products(Rely-X. Variolink II. Choice). Material and method: Color was measured for porcelain disk sample without try-in paste, and porcelain disk sample intermediated by try-in paste and resin cement, then color differences were calculated. Results : 1. Color difference(${\Delta}E^*$) between try-in paste and resin cement showed the lowest value at Variolink II and increased in the order Choice and Rely-X statistically significant, and $?E^*$ of three resin cements was greater in A3 then A1. 2. The values of ${\Delta}L^*$ and ${\Delta}a^*$ between try-in paste and resin cement was in the increasing order of Variolink II, Choice and Rely-X. The ${\Delta}b^*$ value was increased in this order Choice, Rely-X and Variolink II in A1 on the other hand Variolink II, Rely-X and Choice in A3. 3. Color difference(${\Delta}E^*$) before and after resin cement showed the lowest value at Variolink II and increased in the order Rely-X and Choice. Conclusion : Above result revealed that the colors of try-in paste and resin cement were more or less accurate in the range of 0.35-1.95 of color difference which was unnoticeable with human eye, and Variolink II was superior to the other resin cements in color accuracy.

대학생의 쇼핑성향에 따른 백화점 의복 판매원의 평가 속성

김혜영,박하나,유연옥,이지혜,박혜선 배재대학교 자연과학연구소 2004 自然科學論文集 Vol.15 No.1

임플랜트 고정체의 형태와 연결방식에 따른 임플랜트 및 지지조직의 응력분포

한상운,박하옥,양홍서,Han Sang-Un,Park Ha-Ok,Yang Hong-So 대한치과보철학회 2004 대한치과보철학회지 Vol.42 No.2

Purpose: Four finite element models were constructed in the mandible having a single implant fixture connected to the first premolar-shaped superstructure, in order to evaluate how the shape of the fixture and the implant-abutment connection would influence the stress level of the supporting tissues fixtures, and prosthethic components. Material and methods : The superstructures were constructed using UCLA type abutment, ADA type III gold alloy was used to fabricate a crown and then connected to the fixture with an abutment screw. The models BRA, END , FRI, ITI were constructed from the mandible implanted with Branemark, Endopore, Frialit-2, I.T.I. systems respectively. In each model, 150 N of vertical load was placed on the central pit of an occlusal plane and 150 N of $40^{\circ}$ oblique load was placed on the buccal cusp. The displacement and stress distribution in the supporting tissues and the other components were analysed using a 2-dimensional finite element analysis . The maximum stress in each reference area was compared. Results : 1. Under $40^{\circ}$ oblique loading, the maximum stress was larger in the implant, superstructure and supporting tissue, compared to the stress pattern under vertical loading. 2. In the implant, prosthesis and supporting tissue, the maximum stress was smaller with the internal connection type (FRI) and the morse taper type (ITI) when compared to that of the external connection type (BRA & END). 3. In the superstructure and implant/abutment interface, the maximum stress was smaller with the internal connection type (FRI) and the morse taper type (ITI) when compared to that of the external connection type (BRA & END). 4. In the implant fixture, the maximum stress was smaller with the internal connection type (FRI) and the morse taper type (ITI) when compared to that of the external connection type (BRA & END). 5 The stress was more evenly distributed in the bone/implant interface through the FRI of trapezoidal step design. Especially Under $40^{\circ}$ oblique loading, The maximum stress was smallest in the bone/implant interface. 6. In the implant and superstructure and supporting tissue, the maximum stress occured at the crown loading point through the ITI. Conclusion: The stress distribution of the supporting tissue was affected by shape of a fixture and implant-abutment connection. The magnitude of maximum stress was reduced with the internal connection type (FRI) and the morse taper type (ITI) in the implant, prosthesis and supporting tissue. Trapezoidal step design of FRI showed evenly distributed the stress at the bone/implant interface.

도재라미네이트 접착용 레진시멘트의 색조 안정성에 관한 연구

김영운,박하옥,방몽숙,양홍서,박상원,Kim, Young-Woon,Park, Ha-Ok,Vang, Mong-Sook,Yang, Hong-So,Park, Sang-Won 대한치과보철학회 2007 대한치과보철학회지 Vol.45 No.2

Statement of problems: Long-term success of esthetic restorations, depends on various factors, especially on color stability of the restorations. The color stability is affected by resin cements beneath the porcelain laminate veneers. Purpose: The purpose of this study was to comprehend the color stability of resin cements by comparing with 4 different kinds of resin cements (Choice, Variolink II, Nexus 2, Rely-X). Material and methods: Porcelain laminate disk samples were luted with resin cements. After thermocycling of each 1000, 2000 and 3000 cycle, specimens were measured by spectrophotometers and the color differences were. Results: 1. After thermocycling of 1000, 2000 and 3000cycle, color difference, $({\Delta}E^*)$ of all specimens were incresed, but were not statiscally significant differences. 2. In the Choice of A1 shade and the Nexus 2 of A3 shade, color difference$({\Delta}E^*)$ after thermocycling of 3000cycle was $incre^*ased$ significantly than after thermocycling of 1000cycle. However, other groups did not show any statistically significant differences (P<0.05). 3. After thermocycling of 3000cycle, color difference$({\Delta}E^*)$ between A1 shade and A3 shade of Nexus 2 showed statistically significant difference. However no statistically significant differences were observed in other groups (P<0.05). 4. The mean of color difference$({\Delta}E^*)$ is 1.0-2.06 after 3000 thermocycling and the data were ranked in the ascending order of Variolink II, Nexus 2, Choice and Rely-X in A1 shade group and Choice, Rely-X, Variolink II and Nexus 2 in A3 shade group. Conclusion: Above results revealed that, after 3000 thermocycing, the color difference $({\Delta}E^*)$ of experimental resin cements was within clinically acceptable ranges. Color stability of 4 different resin cements was comparatively excellent.

한국 성인의 상악 전치부 인공치아 선택기준에 관한 계측학적 연구

안현정,양홍서,박하옥,Ahn Hyun-Jeong,Yang Hong-So,Park Ha-Ok 대한치과보철학회 2002 대한치과보철학회지 Vol.40 No.5

The selection of the maxillary anterior artificial teeth is made primarily for esthetics and they must be in harmony with the surrounding oral environment. However the selection of artificial teeth is based on the large degree of subjective judgement or the dentists, therefore, this is one of the most unscientific processes. This study was performed to determine clinically whether there is correlation among the width of the maxillary central incisor(WMCI), the intercanine distance (ICD) the facial width(FW), and the interalar nasal width(IAW) in Korean adults, and to provide the selection standards for the maxillary anterior artificial teeth. The casts were obtained from 91 undergraduate dental students(49 males and 42 females) with Angle's class I occlusion presenting well-arranged intact anterior teeth. The WMCI and ICD were measured on the casts with a vernier calipers($Miltex^{(R)}$, Germany). The photographic procedures under standardized conditions were performed to record each subject's frontal face using digital camera($Olympus^{(R)}$, C-2500L, Japan). The FW and IAW were measured with image analyzer($Image-Pro^{(R)}$ PLUS. media cybermetrics. USA). The results were obtained as follows : 1. The mean WMCI was $8.11{\pm}0.67mm$, ICD was $37.88{\pm}2.15mm$, FW was $141.29{\pm}5.84mm$. and IAW was $37.85{\pm}2.29 mm$. 2. The ratios of FW/WMCI, FW/ICD, IAW/ICD were 17.4, 3.7, 1.0 respectively. 3. All measurements(WMCI, ICD, FW, and IAW) of male group were longer than those of female group significantly in Student's t-test(p<0.01). 4. There was significant correlation between WMCI, ICD, FW, and IAW in Pearson's correlation analysis(p<0.01). 5, The relationship between IAW and ICD shows the strongest correlation among six combinations in linear regression analysis($R^2$=0.753, Y=7.046+0.815X). The FW and IAW could be very reliable guides for the selection of the maxillary anterior artificial teeth.

미백 처리된 치아의 표면처리법이 레진과의 결합에 미치는 영향

최낙준,방몽숙,박하옥,Choi Nak-Joon,Vang Mong-Sook,Park Ha-Ok 대한치과보철학회 2002 대한치과보철학회지 Vol.40 No.5

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) group. Here, $opalescence^{(R)}$ (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 be dyed about $20{\mu}m$ deeper with rhodamine B. The DBL group appeared to be caved in at the entry part of the dentinal tubules, was dyed about $20{\mu}m$ deeper and $5{\mu}m$ 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 $50{\mu}m$ 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 statistically significant differences between the ENBLA and the EBLLA groups were observed(p>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.

키토산을 첨가한 의치상 재료의 세균 부착에 관한 연구

정승환,방몽숙,박하옥,Chung Sung-Hwan,Vang Mong-Sook,Park Ha-Ok 대한치과보철학회 2002 대한치과보철학회지 Vol.40 No.5

The purposes of this study were to evaluate the adherence of bacteria on various denture base resin materials and effects of chitosan, added to denture base materials on bacterial adherence. PMMA denture base resin such as heat-cured Vertex-RS, self-cured Vertex-SC and 4-META denture base resin such as heat-cured Meta-Dent, self-cured Meta-Fast were used in this study Samples were divided into two groups the denture base resin with chitosan, without chitosan Streptococcus mutans and Lactobacillus casei were used in this study. The surface of samples was observed by SEM. When chitosan was added to M17 and MRS broth, viable cell count of bacteria was reduced. Viable cell count of Streptococcus mutans on the samples decreased as follows : Meta-Dent, Vertex-SC, Meta-Fast, Vertex-RS. Viable cell count of Lactobacillus casei on the samples decreased as follows: Vertex-RS, Meta-Dent, Meta-Fast, Vertex-SC. The resin with chitosan showed lower adherence of bacteria than without chitosan. The images of SEM showed that the surface of the resin with chitosan was rougher than that of without chitosan. These results showed that the denture base resin materials with chitosan have rougher surface than without chitosan, but less bacteria adhered on them.