• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.1
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• pp.19-25
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• 2004

Dentally disabled person means one who have difficulty in cooperating voluntarily with a dentist for routine dental care. Seoul National University Dental Hospital (SNUDH) Dental Clinic for Disabled has worked for them under outpatient anesthesia concept. The aim of this study was to determine the anesthetic characteristics of the patients attending for dental treatment at SNUDH Dental Clinic for Disabled in order to establish better future treatment plans. The data were drawn from the patients who visited SNUDH Dental Clinic for Disabled from January 1999 to October 2002. Total 93 dental treatments for 83 patients were enrolled in this study. Most patients had mental retardation and the conservative treatments were carried out under general anesthesia. Thiopental and vecuronium were mostly used for induction agent and neuromuscular blocker, respectively. Enflurane, with oxygen and nitrous oxide, was mostly used to maintain the anesthesia. Mean total anesthetic time was $164.4{\pm}57.2$ minutes and mean duration at the post-anesthetic care unit was $106.2{\pm}50.5$ min. Serious postoperative complications were not observed. These results showed our successful anesthetic outcomes without any severe side effect or complication and the needs of more outpatient centers for dental care for disabled.

• Imaging Science in Dentistry
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• v.32 no.3
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• pp.147-151
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• 2002

Purpose: To compare the standard deviation of gray levels on digital subtracted images obtained by different dental subtraction programs. Materials and Methods: Paired periapical films were taken at the lower premolar and molar areas of the phantoms involving human mandible. The bite registration group used Rinn XCP equipment and bite registration material, based on polyvinyl siloxane, for standardization. The no bite registration group used only Rinn XCP equipment. The periapical film images were digitized at 1200 dpi resolution and 256 gray levels by a flat bed scanner with transparency unit. Dental digital subtraction programs used for this study were Subtractor (Biomedisys Co., Korea) and Emago (Oral Diagnostic Systems, The Netherlands). To measure the similarities between the subtracted images, the standard deviations of the gray levels were obtained using a histogram of subtracted images, which were then analyzed statistically. Results: Subtracted images obtained by using the Emago program without manual selection of corresponding points showed the lowest standard deviation of gray levels (p<0.01). And the standard deviation of gray levels was lower in subtracted images in the group of a bite registration than in the group of no use of bite registration (p < 0.01). Conclusion: Digital radiographic subtraction without manual selection of reference points was found to be a convenient and superior method.

• Journal of Periodontal and Implant Science
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• v.42 no.3
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• pp.105-109
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• 2012

Purpose: Soft tissue recessions frequently cause esthetic disharmony and dissatisfaction. Compared with soft tissue coverage around a tooth, the coverage of an implant site is obviously unpredictable. Particularly in the cases of thin mucosa, a significant greater amount of recession takes place compared to thick mucosa. To overcome this problem, this case report demonstrates a two-step mucosal dehiscence coverage technique for an endosseous implant. Methods: A 33-year-old female visited us with the chief complaint of dissatisfaction with the esthetics of an exposed implant in the maxillary left cental incisor region. A partial-thickness pouch was constructed around the dehiscence. A subepithelial connective tissue graft was positioned in the apical site of the implant and covered by a mucosal flap with normal tension. At 12 months after surgery, the recipient site was partially covered by keratinized mucosa. However, the buccal interdental papilla between implant on maxillary left central incisor region and adjacent lateral incisor was concave in shape. To resolve the mucosal recession after the first graft, a second graft was performed with the same technique. Results: An esthetically satisfactory result was achieved and the marginal soft tissue level was stable 9 months after the second graft. Conclusions: The second graft was able to resolve the mucosal recession after first graft. This two-step approach has the potential to improve the certainty of esthetic results.

• The Journal of Advanced Prosthodontics
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• v.7 no.3
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• pp.207-213
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• 2015

PURPOSE. The purpose of this study was to examine the abutment screw stability of screw- and cement-retained implant-supported dental prosthesis (SCP) after simulated cement washout as well as the stability of SCP cements after complete loosening of abutment screws. MATERIALS AND METHODS. Thirty-six titanium CAD/CAM-made implant prostheses were fabricated on two implants placed in the resin models. Each prosthesis is a two-unit SCP: one screw-retained and the other cemented. After evaluating the passive fit of each prosthesis, all implant prostheses were randomly divided into 3 groups: screwed and cemented SCP (Control), screwed and non-cemented SCP (Group 1), unscrewed and cemented SCP (Group 2). Each prosthesis in Control and Group 1 was screwed and/or cemented, and the preloading reverse torque value (RTV) was evaluated. SCP in Group 2 was screwed and cemented, and then unscrewed (RTV=0) after the cement was set. After cyclic loading was applied, the postloading RTV was measured. RTV loss and decementation ratios were calculated for statistical analysis. RESULTS. There was no significant difference in RTV loss ratio between Control and Group 1 (P=.16). No decemented prosthesis was found among Control and Group 2. CONCLUSION. Within the limits of this in vitro study, the stabilities of SCP abutment screws and cement were not significantly changed after simulated cement washout or screw loosening.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.21.1-21.3
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• 2019

Background: Treatment planning the correction of a transverse maxillary occlusal plane cant often involves a degree of qualitative "eyeballing", with the attendant possibility of error in the estimated judgement. A simple chair side technique permits quantification of the extent of asymmetry and thereby quantitative measurements for the correction of the occlusal plane cant. Methods: A measuring instrument may be constructed by soldering the edge of a stainless steel dental ruler at 90° to the flat surface of a similar ruler. With the patient either standing in natural head position, or alternatively seated upright in the dental chair, and a dental photographic retractor in situ, the flat under-surface of the horizontal part of this measuring instrument is placed on a unilateral segment of a bilateral structure, e.g. the higher maxillary canine orthodontic bracket hook. The vertical ruler is held next to the contralateral canine tooth, and the vertical distance measured directly from the canine bracket to the flat under-surface of the horizontal part of the measuring instrument. Results: This vertical distance quantifies the overall extent of movement required to level the maxillary occlusal plane. Conclusions: This measuring instrument and simple chair side technique helps to quantify the overall extent of surgical levelling required and may be a useful additional technique in our clinical diagnostic armamentarium.

• Journal of Technologic Dentistry
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• v.29 no.1
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• pp.93-101
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• 2007

The purpose of this study is to evaluate the effect of three different oblique mechanical loading to occlusal surfaces of posterior implant partial dentures on the stress distributions in surrounding bone, using 3-dimensional finite element method. A 3-dimensional finite element model of a posterior implant partial dentures composed of three unit implants, simplified 3 gold alloy crown and supporting bone was developed according to the design of AVANA self tapping implant for this study. Three kinds of surface distributed oblique loads(300 N) are applied to following occlusal surfaces in the three crowns; 1) All occlusal surfaces in the three crown(load of 300 N was shared to three crown), 2) Occlusal surface of centered crown (load of 300 N was applied to a centered crown), 3) Occlusal surface of proximal crown(load of 300 N was applied to a distal proximal crown). In the results, 141 MPa of maximum von Mises stress was calculated at third loading condition and 98 MPa of minimum von Mises stress was calculated at first loading condition. From the results, location and type of occlusive loading conditions are important for the safety of supporting bone.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.28 no.1
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• pp.4-17
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• 2019

Nowadays, Cone-Beam CT is widely supplied in dental clinics, the distribution rate in south korea is highly ranked worldwidely. Recently, The number of Cone-Beam CTs reached 10 thousands according to national healthcare system report. Also, dental manufacturers released many kinds of In-house 3D digital printers, the distribution rate of which rises rapidly in dental clinics. Accordingly, using Cone-Beam CT data and Intraloral scan data, the application of implant guide surgery is widespread in a unit of private clinic. Through the previous articles, the latest methods of computer-guided implant surgery are reviewed, and also the considerations for precise and reliable guide surgery are summarized.

• Journal of Technologic Dentistry
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• v.12 no.1
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• pp.5-14
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• 1990

The purpose of this study were to investigate the patterns of prosthetic restorations according to sex and age. We had surveyed the out-patents of dental clinics it Jeon-Ju, Iri and Gun roan area. The abtained result were as follow ; 1. The patterns of prosthetic restoration in female was higher than male and 20$\sim$30 age groups was higher than others. 2. The crown was higher in prosthetic restoration. 3. The procelain appliance area was high in male and female on 20$\sim$29 age. 4. The partial denture was higher than full denture in both sex. 5. The crown appliance area was not different in both sex. 6. The 3 unit bridge was higher than other bridge in both sex. 7. The porcelain appliance area was high in male and female on upper anterior. 8. The inlay appliance area of lower posterior was higher than upper posterior. 9. The upper posterior was high in male, and the lower posterior was high in female in partial denture. 10. The full dentur was high in old age group.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.1
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• pp.144-155
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• 1995

It is well known that implants showing no clinical mobility are successfully osseointegrated and have good prognosis. When implants are under load, their mobility begins to increase. It is of necessity to substantiate whether excessive load is on or premature occlusal force is acting prior to desirable osseointegration. Using Periotest unit, we could measure the pattern of mobility change. Consequently, osseointegrated treatment has come to success by intercepting progressive mobility and doing perceptive treatment according to the result of Periotest Value(PTV). In this study, we took records of intangible mobility of 70 osseointegrated implants. And we also measured the mobility of periodontally sound natural teeth as a standard from 30 dental personnel. Conclusions were summarized as followings ; 1. Lower lateral incisor has the highest PTV, whereas lower canine, upper canine, lower premolars and lower 1st molar have the lowest PTV in natural dentition. 2. There are little significant statistical difference of PTV between men and women in both(natural and implant) dentition. 3. In general, lower natural teeth show lower PTV than upper counterpart. 4. Mandibular implants have lower PTV than those of maxillary implants. 5. All of the successfully osseointegrated implants have lower PTV than those of periodontally healthy teeth.

• Imaging Science in Dentistry
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• v.51 no.3
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• pp.261-269
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• 2021

Purpose: The aim of this study was to evaluate the radiopacities of various types of restorative materials with different thicknesses compared with enamel, dentin, and aluminum. Materials and Methods: Four bulk-fill resins, 2 hybrid ceramics, 2 micro-hybrid resin composites, 6 glass ionomer-based materials, 2 zinc phosphate cements, and an amalgam were used in the study. Twelve disk-shaped specimens were prepared from each of 17 restorative materials with thicknesses of 1 mm, 2 mm, and 4 mm (n=4). All the restorative material specimens with the same thickness, an aluminum (Al) step wedge, and enamel and dentin specimens were positioned on a phosphor storage plate and exposed using a dental X-ray unit. The mean gray values were measured on digital images and converted to equivalent Al thicknesses. Statistical analyses were performed using 2-way analysis of variance and the Bonferroni post hoc test(P<0.05). Results: Radiopacity was significantly affected by both the thickness and the material type (P<0.05). GCP Glass Fill had the lowest radiopacity value for samples of 1 mm thickness, while Vita Enamic had the lowest radiopacity value for 2-mm-thick and 4-mm-thick samples. The materials with the highest radiopacity values after the amalgam were zinc phosphate cements. Conclusion: Significant differences were observed in the radiopacities of restorative materials with different thicknesses. Radiopacity was affected by both the material type and thickness.