• 한국치위생학회지
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• 제14권1호
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• pp.101-108
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• 2014

Objectives : The purpose of this study was to evaluate the tooth whitening effect of 0.74% and 2.80% hydrogen peroxide toothpastes and safety on tooth and gingival tissue. Methods : Toothpastes containing 0.74% and 2.80% hydrogen peroxide were evaluated. In in-vitro test, some additives (sodium metaphosphate, sodium pyrophosphate and titanium dioxide) were added to the toothpastes. Hydroxyapatite specimens (HAPs) were made and stained using modified Stookey's methods. HAPs were treated for 1 hour at shaking incubator and brushed for 1,000 times as 250 gF with each diluted toothpaste. Before and after color was measured by colorimeter. Using double blind method, 99 Korean with natural maxillary anterior teeth were selected and the initial brightness (baseline) was measured by SHADEEYE-EX. Based on this measurement they were crossly distributed into control group (0% hydrogen peroxide), test 1 (0.74% hydrogen peroxide) and test 2 (2.80% hydrogen peroxide). After 2 weeks, people of each group were provided toothpaste and told to use 3 times a day right after every meal for 3 minutes. The brightness of teeth was measured 3 times for every one month. Results : ${\Delta}L$ was statistically significant among three groups in shaking test. ${\Delta}L$ of two test groups was statistically significant compared with control group but not between each test group in brushing test. After using toothpaste for 3 months, test 1 group and test 2 group were 15.89% and 31.23% more whitened compared with control group respectively (p<0.05). Rate of more whitened person of each test group was 24.2% and 40.5% more than control group respectively (p<0.05). There was no difference in the hypersensitivity during 3 months using toothpastes and no side effect on teeth or gums. Conclusions : Toothpastes containing 0.74% and 2.80% hydrogen peroxide showed tooth whitening effect and both were safe enough to use for tooth whitening.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권2호
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• pp.124-130
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• 2007

In the present study, I investigated the effects of N-methyl-D-aspartate (NMDA), arachidonic acid (AA), and Nitric Oxide Synthase Inhibitor (NOSI), alone or in combination, on the proliferation of cultured primary normal human oral keratinocytes (NHOK). The purpose of this study was therefore the preliminary study for the examination of the interaction between these agents and NHOK in order to elucidate the mechanisms by which epithelial growth and regeneration are regulated. NHOK were obtained from gingival tissue of 20 individuals aged 20 to 29, and third passage (P3) cells were used for this study. The DNA synthesis was measured by the BrdU assay. Addition of low concentration of AA ($1{\mu}M$) and high concentration of AA with NMDA group (NMDA+AA $10{\mu}M$) made DNA synthesis rate increase significantly at the early stage. Adding NNA ($10{\mu}M$) affected DNA synthesis rate to increase significantly in 4 hours. At the early stage, DNA synthesis was significantly active in the NOS-I with NMDA groups than in the control and the NMDA-only group, while it didn't become statistically meaningful in 24 hours. AA $1{\mu}M$ and NNA $10{\mu}M$ may induce the proliferation of the NHOK independently and NOS-I may induce the proliferation of the NHOK with NMDA. These reactions might be related to the NMDA receptor in the cell and the change of the intracellular calcium ion concentration.

• Journal of Periodontal and Implant Science
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• 제24권1호
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• pp.1-14
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• 1994

Dental calculus which is calcifing and/or calcified dental plaque is divided into supragingival calculus and subgingival calculus according to the position of deposit to gingival margin. Subgingival calculus has more important clinical significance in diagnosis and treatment of periodontal disease than supragingival calculus. In order to investigate the deposition pattern of subgingival calculus on each root surface of different tooth type, extracted 192 teeth due to excessive destruction of periodontal tissue were divided according to tooth type and the deposition pattern of subgingival calculus was classified into linear type, veneer type, scattered type, and aggregated type according to the configuration and the extent of deposit. The difference of percentage between each deposition pattern was statistically analyzed by Chi-Square test. Following results were obtained : l. In maxillary incisors, linear type and aggregated type were predominant deposition pattern of subgingival calculus on labial(45.5%, 36.4%) and palatal(36.4%, 36.4%) root surface, aggreated type(72.7%) was on mesial surface, and aggregated type(54.5%) and scattered type(36.4%) was on distal suface. 2. In mandibular incisors, scattered type, linear type and aggregated type were predominant deposition pattern of subgingival calculus on labial(33.3%, 30.6%, 27.8%) and lingual(36.1%, 30.6%, 25.0%) root surface, aggregated type(33.3%), scattered type(27.8% ), and veneer type(27.8%) were on mesial surface, and aggregated type(38.9%) and scattered type(33.3%) on distal surface. 3. In maxillary peremolars, the predominant deposition patterns of subgingival calculus were linear type(28.6%) on buccal root suface, scattered type(35.7%) and linear type(28.6%) on palatal surface, scattered type(39.3%) on mesial surface, aggregated type(46.4%) on distal surface, and aggregated type(53.6%) on furcation area. 4. In mandibular premolars, scattered type was predominant deposition pattern of subgingival calculus on buccal(39.3%) and lingual(50.0%) root surface, scattered type(32.1%) and aggregated type(32.1% ) were on mesial surface, and aggregated type(42.9%) was on distal surface. 5. In maxillary molars, aggregated type(40.0%) and scattered type(32.5%) were predominat deposition pattern of subgingival calculus on buccal root surface, aggregated type was on distal(40.0%) and furcation area(50.0%), but there was no predominat pattern on palatal and mesial root surfaces. 6. In mandibular molars, aggregated type(39.5%) and scattered type(28.9%) were predominant deposition patterns of subgingival calculus on buccal root surface, aggregated type(36.8%) was on lingual surface, linear type(39.5%) and aggregated type(34.2%) were on furcation area, but there was no predominant pattern on mesial and distal root surfaces.

• Journal of Periodontal and Implant Science
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• 제26권2호
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• pp.511-521
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• 1996

Periodontal pocket is one of the most frequently developed clinical feature on the teeth with periodontal disease. In order to determine the gingival curettage effect of intrapocket irradiation of a pulsed Nd : YAG laser on periodontally involved teeth, bilateral 60 teeth with $4{\sim}6mm$ in probing pocket depth 1 week after supragingival scaling were selected. On half of them the intrapocket irradiation($300{\mu}m$ fiber optic, 1.5W power, for 2min.) of a pulsed-Nd : YAG laser(EL.EN.EN06O, Italy) was applied as the lased group. On the contralateral 30 teeth the subgingival curettage was accomplished by Gracey curettes as the curattage group. The periodontal pocket tissues were surgically excised by the modified Widman flap technique immediately after the intrapocket irradiation or subgingival curettage, subsequently fixed with 10% neutral formalin, sectioned in $4{\sim}6{\mu}m$ thickness, and stained with hematoxylin-eosin. Surface characteristics and incomplete removal of the pocket epithelium were evaluated under light microscope. And the difference between the lased group and the curettage group was statistically analyzed by Chi-square test in Microstat program. The results were as follows ; 1. The plane surface was observed more frequently in the curettage group(73.3%) than in the lased group(23.3%), and the rough surface was observed more frequently in the lased grOoup(63.3%) than in the curettage group(6.7%)(p<0.05). 2. The rate of incomplete removal of the pocket epithelium was relatively high in both the lased group(76.6%) and the curettage group(86.6%), and there was no significant difference between the lased group and the curettage group(p>0.l). The results suggest that the further studies including various power control of laser should be succeeded in order to obtain more favorable results by the intrapocket irradiation of a pulsed Nd:YAG laser than the subgingival curettage with Gracey curettes.

• 대한치과보철학회지
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• 제44권1호
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• pp.29-39
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• 2006

Statements of problem: Zirconia core is used for posterior fixed partial dentures because it's good mechanical properties. Stress is concentrated on connectors in fixed partial dentures, so the proper design of connector areas is needed for adequate mechanical long-term properties of any prosthesis. The area of connector is critical, but tooth size and surrounding soft tissue limit the connector design. Purpose: The purpose of this study is to compare fracture strengths between different connector designs of zirconia core for posterior fixed partial dentures manufactured with CAD/CAM system and determining the optimal connector design satisfying strength and hygiene. Material and method: The following four groups of 40 posterior fixed partial denture specimens(each group 10) were fabricated as followed; group 1 vertical height of connector is 3mm (control group, all groups have the same condition); group 2, lingual vertical 1mm reinforcement on connector; group 3, lingual vertical 2mm reinforcing on connector and group 4, lingual vertical 3mm reinforcing on connector. Specimens were subjected to compressive loading on the central fossa of pontic by instron. SEM was used to identify the initial crack and characterize the fracture mode. Results: The results were as follows: 1. The mean fracture load of the non-lingual reinforcing group was 1212N and the lingual vertical 1mm reinforcing group was 1510N, the lingual vertical 2mm reinforcing group was 1882N, the lingual vertical 3mm reinforcing group was 1980N. 2. The reinforcing groups were statistically significant compared to non-reinforcing groups(P<0.001). 3. There were 2, 3mm reinforcing groups that were statistically significant compared to 1mm reinforcing groups(P<0.001), and the 3mm reinforcing group was not statistically significant compared to 2mm reinforcing groups(P>0.05) 4. Fractures were initiated in gingival embrasures of connectors and processed to the loading site. Conclusion: In this study, lingual reinforcement of connector for improved strength of zirconia based fixed partial denture is nessasary. And long-term study for clinical application is required

• Journal of Periodontal and Implant Science
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• 제34권1호
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• pp.139-148
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• 2004

MMPs(Matrix metalloproteinases)는 치주질환에서 주된 조직파괴단백분해효소인 것은 알려져 있고 TIMPs(Tissue inhibitor of Matrix metalloproteinase)는 MMPs의 작용을 억제한다라고 알려져 있다. 이 둘간의 불균형으로 인해서 조직파괴가 더 가속화될 수 있다. 이 두 연구의 목적은 ELISA kit를 사용하여 특정 MMPs(1,2,3,8,9,13)과 TIMPs(1,2)의 양이 건강한 환자와 비교하여서 치주염 환자에서 달라지는지 알아보고 MMPs(1,2,3,8,9,13), TIMPs(1,2)와 치은열구깊이와 GI score와의 관계를 알아보기로 한다. 8명의 만성 치주염 환자와 4명의 급속진행형 치주염 환자가 실험군으로 참여하였고 5명의 건강한 치주조직을 환자가 대조군으로 참여하였다. 임상적인 측정은 GI score와 치주낭측정을 통하여 이루어졌다. 8명의 만성 치주염을 가진 환자와 4명의 급속진행형 치주염을 가진 환자에서 각각 치주낭 깊이가 3mm이하인 부위에서 6개의 치은열구액 표본과 치주낭 깊이가 6mm 이상인 곳에서 6개의 치은열구액 표본을 채취하였다. 건강한 치주조직을 가진 5명의 환자는 단지 치주낭깊이가 3mm 이하인 건강한 부위에서만 치은열구액 표본을 제공하였다. MMPs(1,2,3,8,9,13)과 MIMPs(1,2)의 측정은 Human Biotrack ELISA kit를 사용하여서 측정하였다. 통계처리는 MMPs, MIMPs의 실험군과 대조군의 차이는 Kruskal-Wallis test를 사용하였고 MMPs, TIMPs와 치주낭 깊이와 GI score의 관계정도는 Pearson's correlation coefficient를 사용하였다. 실험결과 대조군과 비교하여 만성 치주염 환자에서 치주낭 깊이가 6mm 이상인 부위에서 MMP9의 수치가 통계적으로 유의할만하게 높았으며(p=0.04) MIMP2의 수치가 대조군과 비교하여 치주낭 깊이가 3mm 이하인 부위를 가진 만성치주염 환자에서 통계적으로 유의할만하게 높았다(=0.049). MMPs(1,2,3,8,9,13), MIMPs(1,2)의 활동성과 치주낭 깊이의 관계에서 둘간의 통계적으로 유의할만한 관계는 존재하지 않았으나 MMP1(r=0.35)과 MMP2(r=0.31)가 상대적으로 높은 관계를 보였다. 또한 MMPs(1,2,3,8,9,13), MIMPs(1,2)의 활동성과 GI score의 관계에서도 둘간의 통계학적으로 유의할만한 관계는 존재하지 않으나 MMP1(r=0.4), MMP2(r=0.29), MMP9(r=0.26)가 상대적으로 높은 관계를 보였다. 이 실험의 결과로 볼 때 MMP9가 만성치주염 환자의 질환이 있는 부위에서만 염증의 지표가 될 수 있으며 MIMP2가 만성치주염 환자의 염증이 없는 부위에서 높은 농도로 존재하는 것으로 보아서 MIMP2가 MMPs에 대한 억제작용을 하여서 염증의 진행을 방해하는 역할을 한다라고 볼 수 있다.

• 대한치과교정학회지
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• 제36권4호
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• pp.242-250
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• 2006

기계적 응력은 정상적인 발달과정 동안 조직의 항상성에 있어 중요한 역할을 한다. 기계적 응력은 치아 이동과 저작과 같은 상황을 포함한다. 치아 이동과 저작 중에 치주인대 섬유모세포는 기계적 자극을 감지하고 주위의 세포밖 물질과 생체분자 대사의 변동에 의해 반응을 보인다. 그러나 아직까지 기계적 응력 하에서 치주인대 세포에서 발현된 유전자에 관한 연구는 미비한 실정이다. 최근 기계적 응력이 초파리에 존재하는 UNC-50 유전자에 영향을 줄 수 있다고 보고되었다. 또한 UNC-50은 치은 섬유모세포와 비교해 치주인대 섬유모세포에서만 발현된다고 보고되었다. 본 연구에서는 간헐적 교정력 적용 시에 백서의 치아에서 일어나는 치근 및 치주 조직의 조직학적 변화와, UNC-50의 발현 양상을 면역조직학적 염색으로 조사하여 치주인대에서 기계적 응력과 UNC-50의 관련성을 알아보고자 하였다. Sprague-Dawely계 수컷 백서 12마리를 4마리씩 세 군으로 나누어 상악 우측 구치부에 NiTi closed coil spring을 사용하여 40 g 정도의 견인력이 발생하도록 하여 하루에 1시간씩 간헐적인 교정력을 적용한 후 1, 3, 5일 후 치주인대의 조직학적 변화를 관찰하여 다음과 같은 결과를 얻었다. 조직학적 소견에서 상악 제1대구치 근심구개치근의 치근부 1/3에서 압박측은 안장측보다 더 좁은 치주인대공간을 보였고 교정력을 적용시킨 후 3일 후부터 인장측에서 백악모세포 활성으로 인한 백악질 침착이 관찰되었다. UNC-50은 인장측의 분화 중인 백악모세포에서 강한 발현을 보였다. Osteocalcin은 인장측에서 압박측에 비해 신생 백악질에 존재하는 분화 중인 백악모세포를 따라 강한 발현을 보였다. 이상의 연구결과는 UNC-50이 간헐적 교정력 즉 기계적 응력의 변화에 따른 백악모세포의 분화과정에 중요한 역할을 함을 나타낸다. 그러나 이를 명확히 하기 위해서는 교정력 적용 후 UNC-50의 세포내 신호전달과정에 대한 보완연구가 필요할 것이다.

• Restorative Dentistry and Endodontics
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• 제27권2호
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• pp.150-157
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• 2002

One of the latest concepts in bonding are "total etch", in which both enamel and dentin are etched with an acid to remove the smear layers, and "wet dentin" in which the dentin is not dry but left moist before application of the bonding primer Ideally the application of a bonding agent to tooth structure should be insensitive to minor contamination from oral fluids. Clinically, contaminations such as saliva, gingival fluid, blood and handpiece lubricant are often encountered by dentists during cavity preparation. The aim of this study was to evaluate the effect of contamination by hemostatic agents on shear bond strength of compomer restorations. One hundred and ten extracted human maxillary and mandibular molar teeth were collected. The teeth were removed soft tissue remnant and debris and stored in physiologic solution until they were used. Small flat area on dentin of the buccal surface were wet ground serially with 400, 800 and 1200 abrasive papers on automatic polishing machine. The teeth were randomly divided into 11 groups. Each group was conditioned as follows : Group 1: Dentin surface was not etched and not contaminated by hemostatic agents. Group 2: Dentin surface was not etched but was contaminated by Astringedent$^{\circledR}$(Ultradent product Inc., Utah, U.S.A.) Group 3: Dentin surface was not etched but was contaminated by Bosmin$^{\circledR}$(Jeil Pharm, Korea.). Group 4: Dentin surface was not etched but was contaminated by Epri-dent$^{\circledR}$(Epr Industries, NJ, U.S.A.). Group 5: Dentin surface was etched and not contaminated by hemostatic agents. Group 6: Dentin sorface was etched and contaminated by Astringedent$^{\circledR}$. Group 7 : Dentin surface was etched and contaminated by Bosmin$^{\circledR}$. Group 8: Dentin surface was etched and contaminated by Epri-dent$^{\circledR}$. Group 9: Dentin surface was contaminated by Astringedent$^{\circledR}$. The contaminated surface was rinsed by water and dried by compressed air. Group 10: Dentin surface was contaminated by Bosmin$^{\circledR}$. The contaminated surface was rinsed by water and dried by compressed air. Group 11 : Dentin surface was contaminated by Epri-dent$^{\circledR}$. The contaminated surface was rinsed by water and dried by compressed air. After surface conditioning, F2000$^{\circledR}$ was applicated on the conditoned dentin surface The teeth were thermocycled in distilled water at 5$^{\circ}C$ and 55$^{\circ}C$ for 1,000 cycles. The samples were placed on the binder with the bonded compomer-dentin interface parallel to the knife-edge shearing rod of the Universal Testing Machine(Zwick Z020, Zwick Co., Germany) running at a cross head speed or 1.0 mm/min. Group 2 showed significant decrease in shear bond strength compared with group 1 and group 6 showed significant decrease in shear bond strength compared with group 5. There were no significant differences in shear bond strength between group 5 and group 9, 10 and 11.