• Title/Summary/Keyword: dental materials

Search Result 3,529, Processing Time 0.029 seconds

Comparison of capsule type resin modified glass ionomer porosity according to mixing methods (혼합방법에 따른 캡슐형 광중합글라스아이노머의 공극률 비교)

  • Kim, Jung-min;Kim, Jin-Woo;Cho, Kyung-Mo;Lee, Yoon;Kim, Eung-Hyun;Park, Se-Hee
    • Journal of Dental Rehabilitation and Applied Science
    • /
    • v.37 no.4
    • /
    • pp.217-224
    • /
    • 2021
  • Purpose: The purpose of this study was to evaluate the porosity of resin modified glass ionomer (RMGI) by different mixing methods. Materials and Methods: Five specimens were prepared for each groups according to capsules and mixing methods. Two RMGI capsule and two mixing machines were used for this study. One resin-modified glass ionomer cement is Fuji II LC (F2LC) and the other is Photac Fil Quick Aplicap (PFQ). For Mixing of RMGI capsule, Rotomix using rotating motion and CM-II using shaking motion were used. After measuring height, radius and mass of specimens, Density was calculated. And porosity was measured using micro-computed tomography (micro-CT). All data were statistically analyzed using T-test, two-way ANOVA to compare between groups at 95% significance level to evaluate the affect of capsule and mixing method on the porosity. Results: The porosity was observed in all specimens generally. And there is significant differece between porosities according to RMGI capsule and Mixing method. The porosity of PFQ was lower than that of F2LC and the porosity of Rotomix was lower than that of CM-II. Conclusion: There was a difference of porosity according to kind of capsules and mixing methods. When using same capsule, less porosity was observed on PFQ than F2LC. When using same mixing mehod, less porosity was observed on Rotomix than CM-II. Using mixing machine of same coporation as that of RMGI capsule did not lead to lower porosity. Therefore, Selecting optimal mixing machine is important.

A study on the effect of microgroove-fibronectin complex titanium plate on the expression of various cell behavior-related genes in human gingival fibroblasts (인간치은섬유아세포의 다양한 세포행동 관련 유전자발현에 마이크로그루브-파이브로넥틴 복합 티타늄표면이 미치는 영향에 대한 연구)

  • Hwang, Yu Jeong;Lee, Won Joong;Leesungbok, Richard;Lee, Suk Won
    • Journal of Dental Rehabilitation and Applied Science
    • /
    • v.38 no.3
    • /
    • pp.150-161
    • /
    • 2022
  • Purpose: To determine the effects of the microgroove-fibronectin complex surface on the expression of various genes related to cellular activity in human gingival fibroblasts. Materials and Methods: Smooth titanium specimens (NE0), acid-treated titanium specimens (E0), microgroove and acid-treated titanium specimens (E60/10), fibronectin-fixed smooth titanium specimens (NE0FN), acid-treated and fibronectin-immobilized titanium specimens (E0FN), and microgroove and acid-treated titanium specimens immobilized with fibronectin (E60/10FN) were prepared. Real-time polymerase chain reaction experiments were conducted on 44 genes related to cell behavior of human gingival fibroblasts. Results: Adhesion and proliferation of human gingival fibroblast on microgroove-fibronectin complex titanium were activated through four types of signaling pathway. Integrin α5, Integrin β1, Integrin β3, Talin-2, which belong to the focal adhesion pathway, AKT1, AKT2, NF-κB, which belong to the PI3K-AKT signaling pathway, MEK2, ERK1, ERK2, which belong to the MAPK signaling pathway, and Cyclin D1, CDK4, CDK6 genes belonging to the cell cycle signaling pathway were upregulated on the microgroove-fibronectin complex titanium surface (E60/10FN). Conclusion: The microgroove-fibronectin complex titanium surface can up-regulate various genes involved in cell behavior.

Effect of storage condition of resin cement on shear bond strength of the orthodontic bracket (레진시멘트의 보관 조건이 치열교정용 브라켓의 전단접착강도에 미치는 영향)

  • Seul-Gi, Yi;Jin-Woo, Kim;Se-Hee, Park;Yoon, Lee;Eung-Hyun, Kim;Kyung-Mo, Cho
    • Journal of Dental Rehabilitation and Applied Science
    • /
    • v.38 no.4
    • /
    • pp.189-195
    • /
    • 2022
  • Purpose: For orthodontic bracket bonding, light curing resin cement is widely used because the process is convenient, and it can be polymerized at the desired time. This study compared the difference of bonding strength of orthodontic resin cement according to storage condition. Materials and Methods: After acid etching the bovine enamel surface with 37% phosphoric acid, 15 orthodontic brackets for mandible incisors were bonded with Ortho Connect and Orthomite LC according to following three conditions; 1) Immediate after 4℃ refrigeration for 3 months (IR), 2) One day room temperature after 4℃ refrigeration for 3 months (OR), 3) Room temperature for 3 months (RT). The shear bond strength was measured with a universal material tester and failure pattern of the specimen was observed. Two-way ANOVA and One-way ANOVA were used at the 95% significance level. Results: Ortho Connect that was applied immediately after refrigeration showed the maximum shear bond strength. Orthomite that was applied immediately after refrigeration showed the lowest shear bond strength, and the group stored at room temperature for three months showed the highest shear bond strength, and the difference between the two groups was significant. Conclusion: Ortho Connect can be used without worrying about bond strength even if it is used immediately after refrigeration, but Orthomite should be kept at room temperature sufficiently after refrigeration.

Antimicrobial effect of infrared diode laser utilizing indocyanine green against Staphylococcus aureus biofilm on titanium surface (티타늄 표면에 형성한 Staphylococcus aureus 바이오필름에 대한 인도시아닌 그린을 활용한 광역학치료의 항미생물 효과)

  • Seung Gi Kim;Si-Young Lee;Jong-Bin Lee;Heung-Sik Um;Jae-Kwan Lee
    • Journal of Dental Rehabilitation and Applied Science
    • /
    • v.40 no.2
    • /
    • pp.55-63
    • /
    • 2024
  • Purpose: This study aimed to assess the antimicrobial efficacy of an 810-nm infrared diode laser with indocyanine green (ICG) against Staphylococcus aureus on sandblasted, large grit, and acid-etched (SLA) titanium surfaces, comparing its effectiveness with alternative chemical decontamination modalities. Materials and Methods: Biofilms of S. aureus ATCC 25923 were cultured on SLA titanium disks for 48 hours. The biofilms were divided into five treatment groups: control, chlorhexidine gluconate (CHX), tetracycline (TC), ICG, and 810-nm infrared diode laser with ICG (ICG-PDT). After treatment, colony-forming units were quantified to assess surviving bacteria, and viability was confirmed through confocal laser-scanning microscope (CLSM) imaging. Results: All treated groups exhibited a statistically significant reduction in S. aureus (P < 0.05), with notable efficacy in the CHX, TC, and ICG-PDT groups (P < 0.01). While no statistical difference was observed between TC and CHX, the ICG-PDT group demonstrated superior bacterial reduction. CLSM images revealed a higher proportion of dead bacteria stained in red within the ICG-PDT groups. Conclusion: Within the limitations, ICG-PDT effectively reduced S. aureus biofilms on SLA titanium surfaces. Further investigations into alternative decontamination methods and the clinical impact of ICG-PDT on peri-implant diseases are warranted.

A study of growth factors, chondrogenic differentiation of mesenchymal stem cells and cell response by needle size differences in vitro (인간간엽줄기세포의 연골세포 분화 유도 성장인자 및 주사침 크기 차이에 따른 세포반응에 대한 in vitro 연구)

  • Jeongyun Park;Yu Jeong Hwang;Joseph Junesirk Choi;Jin Young Chon;Suk Won Lee
    • Journal of Dental Rehabilitation and Applied Science
    • /
    • v.40 no.1
    • /
    • pp.13-23
    • /
    • 2024
  • Purpose: This aim of this study was to demonstrate growth factors that differentiate human mesenchymal stem cells into chondrocytes and to evaluate cell proliferation enhancement by needle size differences. Materials and Methods: Human mesenchymal stem cells were cultured in chondrogenic medium supplemented with BMP-2, BMP-4, BMP-6, BMP-7, BMP-13, FGF-2, FGF-18, IGF-1, TGF-β1, TGF-β2, TGF-β3 and without growth factors for 14, 21, and 28 days. Then, the expression levels of SOX-5, SOX-6, SOX-9 and FOXO1A were comparatively analyzed. Human mesenchymal stem cells were inoculated into culture dishes using 18, 21, and 26 gauge (G) needles, and cell proliferation was measured after 24, 48, and 72 hours, respectively. Results: In addition to the previously known FGF, IGF-1, and TGFβ1,the BMP family growth factors such as BMP-2, BMP-4, BMP-6, and BMP-7 increased the expression of chondrocyte differentiation genes SOX-5, SOX-6, SOX-9, and FOXO1A. At 48 hours, the 26G group, the smallest needle, showed significant cell proliferation improvement compared to the control group and the 18G group. At 72 hours, the 26G group, the smallest needle, showed significant increase in cell proliferation compared to the control group. Conclusion: Through this study, growth factors with the ability to induce chondrocyte differentiation of human mesenchymal stem cells were investigated, and cell proliferation changes by needle size differences were determined.

Removal Torque Values of Retaining Screws Tightened to Implant-Supported Prosthesis with Different Connection Systems by Various Tightening Technique (다른 연결 시스템을 갖는 임플랜트 상부 구조물에서 조임술식에 따른 지대주 나사의 풀림 토크값에 대한 연구)

  • Kim, Dong-Wook;Choi, Yu-Sung;Jo, In-Ho
    • Journal of Dental Rehabilitation and Applied Science
    • /
    • v.27 no.4
    • /
    • pp.343-358
    • /
    • 2011
  • As implant treatment has become popular, lots of different shapes and materials of the implant upper component have been supplied. And there are also diverse reports about failures including loosening of the abutment screw which is one of the most common reason. Purpose : The purpose of this study is to find out how different screw tightening orders and methods influence on screw loosening according to the different connection systems. The upper component was fabricated by casting method. After fabricating master models that are precisely attached to the upper component, 5 experimental models each for the external connection system and internal connection system were fabricated using splinting impression technique. First, to find out the influence of the screw tightening order, screws were tightened in 3 orders; 1-2-3-4, 2-3-1-4, 2-4-3-1. After tightening, removal torque values (RTV) of each group was measured. And also to find out the influence of screw tightening method, a model with 2-3-1-4 screw tightening order was tightened with 30 Ncm at one time(1-step method) and the RTV was compared with the same order group (2-3-1-4) in the 2 step method. In the external connection system, RTV appeared significantly lower in group 2-3-1-4 than group 2-4-3-1 (p<0.05). And also in the internal connection system, the RTV of group 2-3-1-4 appeared significantly lower than that of group 2-4-3-1 and 1-2-3-4 (p<0.05). When comparing the tightening number of the screw without considering the screw tightening order, the first tightened screw appeared significantly higher RTV than the second one in the external connection system (p<0.05), however there was no significant difference from the first tightened screw to the last tightened screw in the internal connection system. And there was no statistically significant difference between the two screw tightening methods in both internal and external connection system. In the comparison of external and internal connection system, each RTV appeared 16.27 Ncm and 14.25 Ncm and appeared as a statistically significant difference (p<0.05). There was a significant difference in RTV measured according to the screw tightening order. The lowest RTV appeared in the groups started tightening from the middle. There was also a significant difference in RTV between the two connection system groups. A further study is needed to find out the influence factors in RTV and also a study is required related to the load condition.

A Study on the Current Status and Needs of Nutrition Education on Children's Sugar Intake Reduction among the Center for Children's Foodservice Management and Child Care Facilities (어린이급식관리지원센터와 보육시설의 유아 당류 섭취 줄이기 영양교육 실태 및 요구도)

  • Kim, Mi-Hyun;Kim, Nam-Hee;Yeon, Jee-Young
    • The Korean Journal of Food And Nutrition
    • /
    • v.30 no.3
    • /
    • pp.539-551
    • /
    • 2017
  • This study investigated the current status and needs for nutrition education to help reduce children's sugars intake at the Center for Children's Foodservice Management (CCFM, n=115), and Child Care Facilities (CCF, n=646) through an online survey conducted from October $5^{th}$ to $30^{th}$ 2015. A total of 14.8% of CCFM respondents and 31.9% of CCF respondents provided nutrition education on sugars intake to young children as a main topic (p<0.001). A higher percentage (CCFM 47.8%: CCF 42.4%) delivered nutrition education on sugars intake to young children as a sub-component (p<0.001). Over 90% of the CCFM and CCF participants agreed on the necessity of providing nutrition education on sugars intake to children. The most common reasons given for delivering nutrition education on children's sugar intake were "there are many more urgent nutrition education topics" for CCFM, and "insufficient nutrition education information and materials" for CCF. The percentage of nutrition education on children's sugar intake provided to the children's parents was low showing about 20% in the both groups. The percentage of CCFM participants providing nutrition, education on children's sugar intake to the teachers in CCF was also low, showing about 14.8%; however, 68.0% of the CCF participants wanted to received teacher's education on guiding children's sugar intake. Regarding ideas about a nutrition education program on children's sugar intake for young children, most respondents in both groups answered "sugar intake and dental cavities or obesity" for appropriate education contents, "story telling or puppet show" for appropriate education methods, and "dietitian from CCFM and class teacher together" for appropriate educator. For appropriate education time, there was a significantl difference between the CCFM responses (average 2.7 times) and the CCF responses (average 4 times). Based on the above results, we found that implementing nutrition education on children's sugar intake at the CCFM and CCF, was low; however, awareness of the need for nutrition education on children's sugar intake and the program development and supply was very high. Also, the opinions of CCFM and CCF participants about a nutrition education program on children's sugar intake for young children can provide foundation data to develop and implement the CCFM-based nutrition education program.

The Relationship Between Chewing Ability and Health Status in the Long-lived Elderly of Kyungpook Area (경북지역 장수노인의 저작능력과 건강상태)

  • Lee, Hee-Kyung;Lee, Young-Kwon
    • Journal of Yeungnam Medical Science
    • /
    • v.16 no.2
    • /
    • pp.200-207
    • /
    • 1999
  • Background: The objective of this study is to evaluate the effect of the dental and general health in relation to the state of dentition and chewing ability by surveying oral condition and anthropometric measure in order to provide primary statistics for the development of a program which may lead to an improvement in the long-lived elderly health status in a rural community. Materials and Methods: The subjects of this study were 97 rural long-lived elderly(27 males and 70 females) who were over 85 years-old (average age of subjects are $88.14{\pm}3.20$ year old) in Sungju-Gun, Kyungpook Province. Data were collected by using questionnaires and direct measurement of anthropometrics, and oral examination from all 97 subjects on July, 1999. Results: The following results were obtained: 1. 53.6% of all subjects believe that they are healthy. The average values of height, weight, BMI, body fat, lean body fat and total water were $148.8{\pm}11.2cm$, $46.9{\pm}10.5kg$, $21.2{\pm}3.5kg/m^2$, $26.7{\pm}6.9%$, $73.0{\pm}7.1%$, and $53.4{\pm}5.2%$, respectively. 2. The average number of teeth remaining in the subjects were $3.50{\pm}5.71$; the number of maxillary teeth remaining were $1.08{\pm}2.88$; and the number of mandibular teeth remaining were $2.41{\pm}3.76$. The maximum number of teeth remaining among subjects were 22 teeth, and the fully edentulous(no natural teeth) people were 76.3%. The oral conditions of the subjects were 52.6% using denture, 23.7% using natural teeth, and 23.7% masticating edentulous ridge without denture. 3. In terms of oral condition in self-assessment of health, digestive ability, and chewing ability ; On self-assessment of health, 47.1% of those wearing denture group responded as feeling good, 56.5% of those in the group of edentulous without denture, and 65.2% in group of natural teeth only. On self-assessment of digestive ability, 82.4% of those in group of denture responded as feeling good, 65.2% of those in group of no teeth and no denture, and 73.9% of those in group of natural teeth only. On self-assessment of chewing ability, 90.2% of those in the group wearing a denture, 60. 9% of those in the group of no teeth and no denture, and 65.2% of those in the group of natural teeth only. 4. In terms of oral condition in anthropometric measurements; The height, weight, body fat, lean body mass, and total water according to oral conditions were $150.0{\pm}10.7cm$, $49.0{\pm}10.9kg$, $26.9{\pm}6.6%$, $72.7{\pm}7.0%$, $53.2{\pm}5.1%$, respectively, in group wearing a denture, $142.7{\pm}6.0cm$, $43.2{\pm}5.5kg$, $29.5{\pm}7.2%$, $70.8{\pm}6.9%$, $51.8{\pm}5.0%$, respectively, in the group of no teeth and no denture, and $152.3{\pm}14.1cm$, $45.9{\pm}12.6kg$, $23.4{\pm}6.0%$, $75.9{\pm}6.9%$, $55.6{\pm}5.1%$, respectively, in the group of natural teeth only. Conclusion: The subjective measurements of good health were higher denture user, and natural teeth.

  • PDF

Changes of the surface roughness depending on immersion time and powder/liquid ratio of various tissue conditioners (수종의 조직 양화재의 침수시간과 분액비에 따른 표면 거칠기의 변화)

  • Kim, Kyung-Soo;Moon, Hong-Suk;Shim, June-Sung;Jung, Moon-Kyu
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.47 no.2
    • /
    • pp.108-118
    • /
    • 2009
  • Statement of problem: Volume stability, microstructure reproducibility and fluidity along with compatibility with dental stone must be in consideration in order to use tissue conditioner as a material for functional impression. There are few studies concerning the influence of time factor in oral condition on surface roughness of the stone and optimal retention period in the oral cavity considering such changes in surface roughness. Purpose: The purpose of this study was to find out the influence of various kinds of tissue conditioner, its powder/liquid ratio and immersion time on surface roughness of the stone. Material and methods: Materials used in this study were the three kinds of tissue conditioners(Coe-Comfort, Visco-Gel, Soft-Liner) and were grouped into three: group R-mixed with standard powder/liquid ratio that was recommended by the manufacturers, group M-mixed with 20% more powder, group L-mixed with 20% less powder. Specimens were made with the size of 20 mm diameter and 2 mm width. Each tissue conditioner specimens were subdivided into 5 groups according to the immersion time(0 hour, 1 day, 3 days, 5 days, 7 days), completely immersed into artificial saliva and were stored under $37^{\circ}C$. Specimens of which the given immersion time elapsed were taken out and were poured with improved stone, making the stone specimens. Surface roughness of the stone specimens was measured by a profilometer. Results: Within the limitation of this study, the following results were drawn. 1. Major influencing factor on surface roughness of the stone model made from tissue conditioner was the retention period(contribution ratio($\rho$)=62.86%, P<.05) of the tissue conditioner in oral cavity to make functional impression. 2. In case of Coe-Comfort, higher mean surface roughness value of the stone model with statistical significance was observed compared to that of Soft-Liner and Visco-Gel as immersion time changes(P<.05). 3. In case of group L(less), higher mean surface roughness value of the stone model with statistical significance was observed compared to that of R(recommended) and M(more) group as immersion time changes(P<.05). Conclusion: We may conclude that as the retention period of time in oral cavity influences surface roughness of the stone model the most and as the kind of tissue conditioner and its P/L ratio may influence also, clinician should well understand the optimal retention period in oral cavity and choose the right tissue conditioner for the functional impression, thus making the functional impression with tissue conditioner usefully.