• Imaging Science in Dentistry
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• v.31 no.3
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• pp.165-173
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• 2001

Objectives : To evaluate the absorbed and effective doses of spiral and computed tomography for the dental implant planning. Materials and Methods: For radiographic projection, TLD chips were placed in 22 sites of humanoid phantom to record the exposure to skin and the mean absorbed dose to bone marrow, thyroid, pituitary, parotid and submandibular glands and nesophagus. Effective dose was calculated, using the method suggested by Frederiksen et al.. Patient situations of a single tooth gap in upper and lower midline region, edentulous maxilla and mandible were simulated for spiral tomography. 35 axial slices (maxilla) and 40 axial slices (mandible) with low and standard dose setting were used for computed tomography. All the radiographic procedures were repeated three times. Results: The mean effective dose in case of maxilla was 0.865 mSv, 0.452 mSv, 0.136 mSv and 0.025 mSv, in spiral tomography of complete edentulous maxilla, computed tomography with standard mAs, computed tomography with low mAs and spiral tomography of a single tooth gap (p<0.05). That in case of mandible was 0.614 mSv, 0.448 mSv, 0.137 mSv and 0.036 mSv, in spiral tomography of complete edentulous mandible, computed tomography with standard mAs, computed tomography with low mAs and spiral tomography of a single tooth gap (p<0.05). Conclusions: Based on these results, it can be concluded that low mAs computed tomography is recommended instead of spiral tomography for the complete edentulous maxilla and mandible dental implant treatment planning.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.4
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• pp.710-716
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• 1998

It is one of difficulties to control children who show definitely negative behavior in dental clinic. In such a case, the pharmacologic management has been used to provide quality care, minimize the extremes of disruptive behavior, promote a positive psychologic response to treatment and patient welfare and safety. Deep sedation can be defined as a controlled, pharmacologically-induced state of depressed consciousness from which the patient is not easily aroused which may be accompanied by a partial loss of protective reflexes. In this retrospective report, the sedation records of 200 pediatric dental patients of ASA Class I & II who were not successfully treated under conscious sedation were used for analysis. Most frequently used regimen of deep sedation was the co-medication of midazolam(0.3mg/kg), enflurane(1.0-2.0 vol%) and 50-70% $N_2O_2$. The average age and weight of the patients was 4.6 yr (S.D: 2.72) and 18.7kg(S.D: 6.35) respectively. The average operative time was 52 minutes and midazolam (0.1-0.2cc) was additionally administered intranasally to prolong the operative time as needed. The episodes of untoward side effects were reported during and/or after the procedure in 58 patients. Serious adverse reactions such as cyanosis or laryngospasm were even reported in 7 patients but without mortality. Deep sedation is a very effective way of completing the dental treatments for those who failed to respond well to the conscious sedation. This technique has many practical advantages over general anesthesia case but the demands for the rigid monitoring criteria limit its use in general practice setting. The continuous efforts to improve the safety of the medication and the technique are required for the benefits of the patients and parent.

• Journal of Technologic Dentistry
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• v.39 no.4
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• pp.235-242
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• 2017

Purpose: The aim of this study was to evaluate the marginal and internal gap of zirconia copings fabricated by CAD/CAM system and to research the effect of cement space on the fit of zirconia prosthesis. Methods: Zirconia copings were designed using 3shape software and then milled from presintered zirconia blocks by Kavo dental milling machine. The cement space was set at $0{\mu}m$ around the margins for all groups, and additional cement space appling 1 mm above the finish lines of tooth. The samples were classified into 4 groups according to the cement space setting(Cs-0, Cs-40, Cs-80, Cs-120). Replica technique used to investigate marginal and internal gap. The silicone film thickness was recorded using a optical microscope with image software analysis system at 75${\times}$magnification. The assessment performed on the six points in bucco-lingual and mesio-distal sections(4 groups, 10 copings per group, 12 measuring points per coping). The data were statistically analyzed with one-way ANOVA followed by pair-wise Tukey's post hoc tests(${\alpha}$<0.05). Results: Better marginal and internal fit values were exhibited by $80{\mu}m$ cement space. The results showed that different cement space values had statistically significant effect on the marginal and internal gap of zirconia copings(p<0.001). The gap of margin and axial wall area was smaller than that the gap of occlusal area in all groups(p<0.001). Conclusion : Effect of different cement spaces on the marginal and internal gap of zirconia copings.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.11 no.2
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• pp.76-80
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• 2015

Mental retardation is one of the major disorders covered in special care dentistry. Patients show poor oral health and are a challenge for the dentist due to lack of cooperation. Triazolam is a short-acting benzodiazepine and has been used in the dental office for many years because of its favorable properties. In this study, five patients with mental retardation were sedated with triazolam on a dental out-patient setting. Patients were administrated with 0.25 mg or 0.5 mg of triazolam on the first dose according to the patient's cooperation. Twenty minutes after the initial dose, patients received 0.25 mg of triazolam. Triazolam was administrated sublingually to one patient and orally to four patients. Hydroxyzine was also administrated to three patients in order to prevent nausea and vomiting. All patients were inhaled with 50% nitrous oxide during the sedation. Treatment time ranged from 20 minutes to 55 minutes. Two patients showed paradoxical reactions and were administrated with intramuscular injections of flumazenil. In result, depending on the range of dental treatment and level of intellectual disability, we can assume that triazolam may be beneficial for sedation in disabled patients.

• Imaging Science in Dentistry
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• v.53 no.4
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• pp.365-373
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• 2023

Purpose: In the context of COVID-19, studies evaluating the adherence of dentists and dental students to infection control are relevant due to their high occupational exposure and risk, as well as their responsibility for disseminating information and good practices. This study evaluated the adherence of dentists and dental students to infection control in the oral radiology field in the setting of the COVID-19 pandemic on different continents. Materials and Methods: This cross-sectional observational study involved individuals who performed intraoral radiographic examinations during the COVID-19 pandemic. The Questionnaire on Infection Control in Oral Radiology was administered virtually using a Google Form. Participants from different continents(the Americas, Africa, Europe, Asia, and Oceania) were recruited. Data were subjected to descriptive analysis and simple and multiple binary regression (5%). Results: There were 582 valid answers, and 68.73% of the participants were from the Americas, 18.90% from Europe, and 12.37% from Asia. The median score for infection control protocols was 94 points for dental students and 104 points for dentists, and participants below the median were considered to have low adherence to infection control in oral radiology. Low access to infection control was found for 53.0% of dentists in the Americas, 34.0% from Europe, and 26.9% from Asia. Conclusion: The adherence to infection control protocols in oral radiology was low even in the face of the COVID-19 pandemic. The results may help improve the awareness of students and professionals, since oral radiology routines have the potential for transmitting COVID-19.

• The Journal of the Korean dental association
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• v.55 no.8
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• pp.516-526
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• 2017

Objective: To suggest diagnostic reference levels (DRLs) for dental panoramic radiography in adults and children through the nationwide survey in Korea. Materials and Methods: Two hundred twelve dental institutions on a national basis were visited. The radiographic examination protocols were surveyed and their patient doses at the clinical exposure setting for adult and children (5- and 10-year old) were measured at 244 panoramic radiographic equipment. The measured DAP were analyzed and compared according to age group, the size of hospital, the type of radiographic system, the installation duration of equipment. Results: The mean exposure parameters were 70.1 kV, 9.2 mA, 14.4 second for adult and 66.6 kV, 7.9 mA, 13.8 second for 10-year old child and 65.5 kV, 7.3 mA, 13.7 second for 5-year old child. The mean and third quartile patient DAPs were $138.3mGy\;cm^2$ and $151.0mGy\;cm^2$ for adult, $99.5mGy\;cm^2$ and $104.8mGy\;cm^2$ for 10-year old child and $89.5mGy\;cm^2$ and $95.5mGy\;cm^2$ for 5-year old child. The mean patient dose at the university dental hospital was lower than that at the dental clinic (p<0.05). The mean patient dose of direct digital radiography type was higher than that of film-based type. However, the difference did not show statistically significance. Conclusion: DRLs for dental panoramic radiography in adult, 10- and 5-year old child were suggested to be $151mGy\;cm^2$, $105mGy\;cm^2$, and $96mGy\;cm^2$ in Korea based on this nationwide survey.

• Imaging Science in Dentistry
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• v.47 no.2
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• pp.109-115
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• 2017

Purpose: The aim of this study was to assess the ex vivo diagnostic ability of 9 different cone-beam computed tomography (CBCT) settings in the detection of recurrent caries under amalgam restorations in primary teeth. Materials and Methods: Fifty-two primary teeth were used. Twenty-six teeth had dentine caries and 26 teeth did not have dentine caries. Black class II cavities were prepared and restored with amalgam. In the 26 carious teeth, recurrent caries were left under restorations. The other 26 intact teeth that did not have caries served as controls. Teeth were imaged using a $100{\times}90-mm$ field of view and a 0.2-mm voxel size with 9 different CBCT settings. Four observers assessed the images using a 5-point scale. Kappa values were calculated to assess observer agreement. CBCT settings were compared with the gold standard using a receiver operating characteristic analysis. The area under the curve (AUC) values for each setting were compared using the chi-square test, with a significance level of ${\alpha}=.05$. Results: Intraobserver kappa values ranged from 0.366 to 0.664 for observer 1, from 0.311 to 0.447 for observer 2, from 0.597 to 1.000 for observer 3, and from 0.869 to 1 for observer 4. Furthermore, interobserver kappa values among the observers ranged from 0.133 to 0.814 for the first reading and from 0.197 to 0.805 for the second reading. The highest AUC values were found for setting 5 (0.5916) and setting 3 (0.5886), and were not found to be statistically significant(P>.05). Conclusion: Variations in tube voltage and tube current did not affect the detection of recurrent caries under amalgam restorations in primary teeth.

• Journal of Periodontal and Implant Science
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• v.39 no.4
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• pp.385-390
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• 2009

Purpose: In this study we evaluated the morphologic aspects of defects created by a piezoelectric ultrasonic scaler with scaler tip on casting gold alloy using scanning electron microscope (SEM) images and defect surface profiles. Methods: 54 blocks of type III casting gold alloy (Firmilay, Jellenko Inc, CA, USA) were scaled by a piezoelectric ultrasonic scaler (P-MAX, Satelec, France) with scaler tip (No. 1 tip) on a sledge device. 2-dimensional profiles of defects on all samples were investigated by a surface profilometer (a-Step 500, KLA-Tencor, CA, USA). The selected working parameters were lateral force (0.5 N, 1.0 N, 2.0 N), mode (P mode, S mode), and power setting (2, 4, 8). SEM images were obtained. Defect surface profiles were made on Microsoft Excel program using data obtained by a surface profilometer. Results: Among P mode samples, there were similarities on defect surface profiles and SEM images regardless of lateral force. The defects created in P mode were narrow and shallow although the depth and the width increased as power setting changed low (2) to high (8). In P mode samples, the defect depth was the greatest when lateral force of 0.5 N was applied. However all the depths were smaller than 1 m. SEM images of Lateral force of 0.5 N, S mode, power setting 2 and 4 were similar to that of P mode, but the other SEM images of S mode showed discernible changes. Defect depth of S mode samples was the greatest when lateral force of 1.0 N was applied. Conclusions: Within the limitations of this study, it can be concoluded that removing capability of piezoelectric scaler with scaler tip becomes maximized as power level becomes higher but the capability is restricted when excessive lateral force is applied on scaler tip.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.3
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• pp.255-260
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• 2008

STATEMENT OF PROBLEM: Preparation of implant beds with lasers is considered a safe and reliable method, but the accuracy of this technique has not been examined. PURPOSE: The purpose of this study was to evaluate the accuracy and effectiveness of implant bed preparation using an Er,Cr:YSGG laser. MATERIAL AND METHODS: An Er,Cr:YSGG laser was applied to pig rib bone. The laser was employed at a 5.75 W power setting, 30 Hz/sec pulse repetition, and 70 ${\mu}s$ pulse duration with 50 % water and 60% air spray. According to laser tips the groups were divided as follows; Group 1: paralleled - shaped sapphire tip (0.6 mm${\Phi}$), Group 2: paralleled - shaped zirconia tip (0.6 mm${\Phi}$), Group 3: tapered sapphire tip (0.4 mm${\Phi}$). The Er,Cr:YSGG laser tip was separated by 1 mm from the bone and applied for 15 seconds in a non-contact mode. After the application, the bone was sectioned for specimens. Histologic measurements were determined by computerized morphometry. The length of the prepared bone surface was measured and the width of the entrance was measured. The results were analyzed with one-way ANOVA (P<0.05). RESULTS: The prepared length of group 3 was longer than that of group 2. The prepared bone width was larger than the width of the laser tip in every group. Additional bone removal was observed adjacent to the prepared area and displayed an irregular surface. CONCLUSION & DISCUSSION: Different cutting effects were observed according to the laser tip, emphasizing the importance of proper tip selection in the clinical setting. This preliminary study supported the existence of hydrokinetic effects.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.78-83
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• 2009

In case of endodontic treatment and extensive restoration of severe dental caries, trauma, and developmental defect, esthetic restoration of primary incisors and permanent anterior teeth for children and adolescents period is delicate matter for pediatric dentists. Existing restorative methods for anterior teeth have retentive and esthetic limitations for badly damaged teeth, especially for the adolescent anterior teeth. Therefore, the preparative stage for setting the permanent prosthesis as well as the retention and esthetics have to be considered. In this case, esthetic restoration for badly destroyed anterior teeth was tried with fiber-reinforced post and the result was satisfactory.