• The Journal of Korean Academy of Prosthodontics
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• v.36 no.1
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• pp.64-80
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• 1998

The risk of cross-contamination in dental clinic is very high. Those who are engaged in dental clinic are exposed to various microorganisms in saliva and blood of patient. Potential possibility of cross-contamination of patient to patient, patient to dentist, dentist to laboratory technician always exist, which is important in the view of public health. It is well known that microorganisms may cause cross-contamination by suck-back of microorganisms into the water supply line or air supply line of dental unit and sprayed back into the next patient's oral cavity. The majority of microorganisms coming from dental unit are water microorganisms from the main water supply which have colonized the tube within the units and multiplied in the relatively warm and stagnant conditions. The purpose of this study is to measure the extent of microbial contamination of dental unit and ultrasonic scaler, to evaluate that dental unit water supply is suitable for drinking water, and to assess the effect of flushing on reduction of microbial contamination of dental unit and ultrasonic scaler. In the first experiment, water samples(50ml) from 20 dental units and 10 ultrasonic scalers in Seoul National Univ. Hosp. were tested for the presence of coliform. The samples were filtered by membrane filtration technique.(Microfil system, Millipore Co. U. S. A.) The filter was then placed onto MacConkey agar plate and the plates with filter on it were incubated aerobically at $37^{\circ}C$ for 5 days. The colors and shapes of colonies were examined if those were coliform. To verify the presence of coliform, the colonies were inoculated into phenol red lactose broth and incubated aerobically at $37^{\circ}C$ for 2 days. The fomation of gas was observed. In the second experiment, water samples from 20 handpieces, 10 ultrasonic scalers and 30 A/W syringes after 0, 2, 4, 6 min. flushing respectively were taken. $200{\mu}l$ water samples were spreaded on Brain Heart Infusion agar plate and the plates were incubated aerobically at $37^{\circ}C$ for 5 days. The number of colony was counted. The results obtained were summarized as follows 1. The water from dental unit and ultrasonic scaler was not suitable for drinking water. 2. No coliform was founded in dental unit and ultrasonic scaler water supply. 3. The number of colony of dental unit and ultrasonic scaler was highest in the group of o min. flushing(p<0.05). 4. There was no statistically significant difference in the extent of microbial contamination among handpiece, ultrasonic scaler and A/W syringe (p>0.05). 5. The number of colony was lowest in the group of 4 min. flushing, but there was no statistically significant difference among 2, 4, 6 min. flushing groups.(p>0.05) 6. It is recommended to flush dental unit water line for 4 min. after use on each patient.

• Journal of Veterinary Clinics
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• v.29 no.3
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• pp.255-258
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• 2012

A 14-year-old spayed female, Shihtzu dog, presented with anorexia, depression and respiratory distress. She had a history of mastectomy for mammary gland tumor before 2 weeks. Severe gingivitis, dental plaque, and calculus were confirmed on physical examination. On auscultation, the dog had a diastolic and systolic murmur at the left heart base and right heart apex respectively. The dog had valvular vegetation including tricuspid and aortic valves with regurgitation on echocardiography. Blood culture was performed to confirm bacterial endocarditis and identify pathogens of bacterial endocarditis. Before the result of blood culture was confirmed, antibiotic (cefalexin, 30 mg/kg, PO, q12hr) with furosemide (2 mg/kg, PO, q12hr) and benazepril (0.25 mg/kg, PO, q12hr) were administered empirically and the patient was well controlled. Staphylococcus pseudintermedius was confirmed later. One week later, however, the patient died of acute respiratory distress caused by fulminant pulmonary edema. The owners denied necropsy of the patient.

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.165-171
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• 2015

This in vitro study compared the effect of bleaching agent modified by the addition of $TiO_2$ catalyst converged bleaching agent. Nonvital teeth samples were assigned to four group(n=6) according to the bleaching agent: 10% carbamide peroxide(CP) bleaching agen, 10% CP with 10% $TiO_2$ catalyst, 20% CP bleaching agent and 20% CP with 20% $TiO_2$ catalyst. Changes in enamel color were evaluated on minutes 30, 60, 180, 300 and 420. It was found that 20% CP with 20% $TiO_2$ catalysis increased the whiteness and overall color value and showed significantly brightened. The teeth bleaching time was reduced with $TiO_2$ catalyst converged bleaching agent. This result will contribute to development of the teeth bleaching agent.

• Journal of Oral Medicine and Pain
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• v.34 no.1
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• pp.1-9
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• 2009

Liver transplantation is definitive treatment for the patients suffering from hepatitis, severe liver cirrhosis and liver cancer. In these patients, systemic infections under immunosuppression may occur easily. Therefore, primary object of dental treatments before liver transplantation is absolute removal of oral infection source. In addition, comprehensive dental management plan is essential for success of liver transplantation. The present study has been performed to investigate decayed, missing and filled permanent teeth index(DMFT index), degree of oral hygiene, past medical history, need of dental treatment, completion of dental treatment need and time interval between dental visit and operation date of liver transplantation in liver transplant candidates. Obtained results were as follows; 1. Decayed teeth of the patients were 2.68, missing teeth were 4.02 and filled teeth were 3.42. DMFT index was 10.12. 2. Twenty percents of patients showed moderate to severe food impactions, 42.2% of patients had moderate to heavy calculus and 37.8% of patients displayed gingival inflammation with swelling. 3. Patients needed periodontal treatments more than any other dental treatments. Periodontal treatments were needed for 88.9% of patients, operative & endodontic treatments were 46.7% of patients and 33.3% of patients needed for oral & maxillofacial surgical treatments. 4. Among 90 patients, time interval between scheduled operation date of liver transplantation and dental visit was within 2 weeks for 32.2% of patients, within 1 week for 20.0% of patients. In conclusion, most liver transplant candidates needed dental treatments for removal of potential infection sources. However because of insufficient interval between dental visit and operation date, they had taken liver transplantation procedures without comprehensive dental management. Development of preventive and comprehensive dental management program is mandatory for these patients. Cooperative interdisciplinary management will play a positive role for successful liver transplantation.

• Journal of dental hygiene science
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• v.11 no.2
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• pp.91-97
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• 2011

The aim of this study was to investigate the prevention effect of oral disease on the school-based toothbrushing program(SBTBP) in Daejeon in 30 months. The experimental subjects were the 5th grade's 70 students who have gone to school with the school-based toothbrushing program since the 3th-grade. The control school was located in close geographical area with similar economical status. The questionnaire about oral health knowledge and behavior was done by self-recording. After one dentist examined the dental caries and periodontal status, the gingival crevicular fluid(GCF) was collected with #25 paperpoint for 1 miniutes. Matrix Metalloproteinase(MMP)-9 in GCF was analyzed by ELISA. The SBTBP group had the upper oral health knowledge than the control significantly(p<0.001), but, the SBTBP group had no difference of the oral health behavior from the control. Although the SBTBP group had the lower plaque index than the control significantly(p=0.02), the SBTBP group had no difference of the gingival index, calculus index and the concentration of MMP-9 in GCF from the control. In conclusion, The SBTBP had the effect to reduce the dental plaque and to improve the oral health knowledge. On the other hand, the effect to prevent dental caries and periodontal disease of SBTBP was not clear.

• Journal of Periodontal and Implant Science
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• v.23 no.3
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• pp.535-563
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• 1993

New techniques for regenerating the destructed periodontal tissue have been studied for many years. Current acceptable methods of promoting periodontal regeneration alre basis of removal of diseased soft tissue, root treatment, guided tissue regeneration, graft materials, biological mediators. Platelet-derived growth factor (PDGF) is one of polypeptide growth factor. PDGF have been reported as a biological mediator which regulate activities of wound healing progress including cell proliferation, migration, and metabolism. The purposes of this study is to evaluate the possibility of using the PDGF as a regeneration promoting agent for furcation involvement defect. Eight adult mongrel dogs were used in this experiment. The dogs were anesthetized with Pentobarbital Sodium (25-30 mg/kg of body weight, Tokyo chemical Co., Japan) and conventional periodontal prophylaxis were performed with ultrasonic scaler. With intrasulcular and crestal incision, mucoperiosteal flap was elevated. Following decortication with 1/2 high speed round bur, degree III furcation defect was made on mandibular second(P2) and fourth(P4) premolar. For the basic treatment of root surface, fully saturated citric acid was applied on the exposed root surface for 3 minutes. On the right P4 20ug of human recombinant PDGF-BB dissolved in acetic acid was applied with polypropylene autopipette. On the left P2 and right P2 PDGF-BB was applied after insertion of ${\beta}-Tricalcium$ phosphate(TCP) and collagen (Collatape) respectively. Left mandibular P4 was used as control. Systemic antibiotics (Penicillin-G benzathine and penicillin-G procaine, 1 ml per 10-25 1bs body weight) were administrated intramuscular for 2 weeks after surgery. Irrigation with 0.1% Chlorhexidine Gluconate around operated sites was performed during the whole experimental period except one day immediate after surgery. Soft diets were fed through the whole experiment period. After 2, 4, 8, 12 weeks, the animals were sacrificed by perfusion technique. Tissue block was excised including the tooth and prepared for light microscope with H-E staining. At 2 weeks after surgery, therer were rapid osteogenesis phenomenon on the defected area of the PDGF only treated group and early trabeculation pattern was made with new osteoid tissue produced by activated osteoblast. Bone formation was almost completed to the fornix of furcation by 8 weeks after surgery. New cementum fromation was observed from 2 weeks after surgery, and the thickness was increased until 8 weeks with typical Sharpey’s fibers reembedded into new bone and cementum. In both PDGF-BB with TCP group and PDGF-BB with Collagen group, regeneration process including new bone and new cementum formation and the group especially in the early weeks. It might be thought that the migration of actively proliferating cells was prohibited by the graft materials. In conclusion, platelet-derived growth factor can promote rapid osteogenesis during early stage of periodontal tissue regeneration.