• Restorative Dentistry and Endodontics
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• v.6 no.1
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• pp.123-132
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• 1980

The author conducted a dental survey of a college girl students and compared with that of E college students 10 years ago which based on the same criteria. The items of this survey included the prevalence of dental caries, DMFT and the kinds of restored material. All college students 1,414 were examined in May 1978, with the recommended criteria and method of W.H.O.. Among them, the data of 1,393 were analyzed for this study. The following results were obtained: 1. The average number of present teeth were 28.97${\pm}$1.64. 2. The prevalence of dental caries was 84.92% and D.M.F. index was 15.51. Average D.M.F. teeth were 4.49${\pm}$3.69. 3. The average number of decayed (D) teeth were 2.09${\pm}$2.16. 4.30% of the present decayed teeth was secondary decay, and 2.44% of the decayed teeth was indicated for extraction. 4. The average number of missing(M) teeth were 0.32${\pm}$0.79. It included 8.56% of root fragements. 5. Average number of filled(F) teeth were 2.09${\pm}$3.17. F-ratio of this group was 46.45%. The analysis revealed 50.88% of amalgam alloy, 31.41% of gold inlays, and 1.20%, the least among the filling materials, silicate cement or composite resin. 6. While the prosthodontic treatment, such as crown and bridge has reduced than that of 10 years ago, the fillings and inlays as the conservative means has increased.

• Journal of Technologic Dentistry
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• v.31 no.4
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• pp.55-66
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• 2009

This research collected the curriculum for Dental Technology from a total of 20 schools --3-year colleges and 4-year colleges-- all in Korea. And we analyzed the average credits of subjects from students. As a result of this analysis, we get the conclusion below: 1. In the arithmetic mean of the major basis subjects which graduates and undergraduates answered about each subjects; Seminar, Dental morphology I II, Dental morphology practice I II, and Dental devices & instruments don't have many credits. And averages of the major application subjects credits which are Implants(especially low), Occlusal anatomy practice I II, Dental ceramics practice I II, and Dental ceramics practice are low, mostly have a converged tendency in high points. 2. In an analysis of the correlation which is based on the major basis subjects: Dental esthetic, oral anatomy I II, Dental materal practice III, Dental casting pracedure, Oral hygiene, Health & medical law, Management administration, and Medical terminology have a meaningful difference. (${\rho}$ < 0.05) 3. In an analysis of the correlation which is based on the major application subjects; Crown and bridge prosthodontics practice IV, Complete denture prosthodontics I II III, Complete denture prosthodontics practice I II III, Dental ceramics I II, Dental ceramics practice I II, Dental ceramics practice IIII, Occlusal anatomy I II, Occlusal anatomy practice I, Operative dentistry laboratory technology I, Operative dentistry laboratory technology practice II, Dental attachment laboratory technology practice, Implants, and Dental laboratory clinical practice have meaningful difference. (${\rho}$ < 0.05) 4. In an analysis of the correlation which is based on the ratio of a theory to an actual training; 40:60(38.57%) is the highest, followed by 30:70(30.04%), 50:50(23.32%), 60:40(5.83%), and 70:30(2.24%). These have meaningful difference. (${\rho}$ < 0.05) 5. In an analysis of the correlation which is based on the distinction of sex: Partial denture prosthodontics practice I II III, Complete denture prosthodontics I II III, Complete denture prosthodontics practice I II III, Occlusal anatomy practice I II, Implants, Medical terminology have meaningful difference. (${\rho}$ < 0.05) For the purpose of training entrepreneurs of middle standing who is required by a future society, Department of Dental Technology's Curriculum need to be managed with planning a curriculum which reflects opinions of graduates, undergraduates and a society, and also are considered not focusing on a supplier but focusing on a user.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.25 no.1
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• pp.25-34
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• 2016

Treatment of missing mandibular 4 incisors is often thought to be easier then other place during surgical and prothetic procedure. But clinicians encounter unexpected difficulties such as restricted implant site due to mesio-distal width of mandibular incisors, limited space as a result of crowing and mesial drift, esthetic problem after severe alveolar bone resorption, and difficulties of provisionalization Through cases, possible treatment options for missing mandibular incisors would be discussed. Treatment options for missing mandibular 4 incisors Place narrow type implant or one body mini implant on exact tooth position when there is no bone resorption Regular size implant on interseptal bone area when there is severe bone resorption Consider using resin bonded bridge(resin retained bridge/resin bonded fixed partial denture) as a tentative prosthesis when patient resists extracting remaining incisors with poor prognosis.

• Restorative Dentistry and Endodontics
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• v.41 no.1
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• pp.29-36
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• 2016

Objectives: The purpose of this study was to assess the ability of two new calcium silicate-based pulp-capping materials (Biodentine and BioAggregate) to induce healing in a rat pulp injury model and to compare them with mineral trioxide aggregate (MTA). Materials and Methods: Eighteen rats were anesthetized, cavities were prepared and the pulp was capped with either of ProRoot MTA, Biodentine, or BioAggregate. The specimens were scanned using a high-resolution micro-computed tomography (micro-CT) system and were prepared and evaluated histologically and immunohistochemically using dentin sialoprotein (DSP). Results: On micro-CT analysis, the ProRoot MTA and Biodentine groups showed significantly thicker hard tissue formation (p < 0.05). On H&E staining, ProRoot MTA showed complete dentin bridge formation with normal pulpal histology. In the Biodentine and BioAggregate groups, a thick, homogeneous hard tissue barrier was observed. The ProRoot MTA specimens showed strong immunopositive reaction for DSP. Conclusions: Our results suggest that calcium silicate-based pulp-capping materials induce favorable effects on reparative processes during vital pulp therapy and that both Biodentine and BioAggregate could be considered as alternatives to ProRoot MTA.

• Journal of Technologic Dentistry
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• v.45 no.2
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• pp.39-47
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• 2023

Purpose: This study aimed to confirm the applicability of gloss polishing using automatic barrel finishing with respect to three-dimensional (3D)-printed resin specimens. The surface roughness and grinding angle of the 3D-printed resin specimens were observed with respect to gloss polishing time using automatic dental barrel finishing. Methods: Herein, experiments were conducted on four types of 3D-printed resin specimens. The specimens, with a thickness of 100 ㎛ each, were printed using a 3D printer. Subsequently, light polymerization was performed on these specimens for 15 min. Post this surface treatment, the specimens underwent grinding for 25 min. This process was followed by gloss polishing at 5-min intervals for up to 25 min using automatic dental barrel finishing. The specimens were photographed using a 3D optical microscope, and their surface roughness and grinding angle were measured. Results: The Ra (centerline average roughness) values of all the specimens, except for crown & bridge 10 group and those in the control group that were not polished using automatic barrel finishing, were <0.2 ㎛. However, polishing time needs to be controlled to realize the desired surface roughness and grinding amount considering the hardness of the resin used. Conclusion: Gloss polishing of 3D-printed resin can be realized using automatic dental barrel finishing. However, polishing time needs to be controlled to realize the desired surface roughness and grinding amount considering the hardness of the resin used.

• Journal of Technologic Dentistry
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• v.28 no.1
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• pp.27-41
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• 2006

The physical property and phase transformation in a commercial dental casting high gold alloy was investigated as a function of ageing temperature and time using microvickers hardness tester, X-ray diffraction, optical and electron microscopy and EPMA analyser. 1. With increasing ageing time, the hardness of solution-treated gold alloys increased slowly at the initial stage of ageing treatment at an ageing temperature of $300{\sim}400^{\circ}C$, and it reached a maximum value of hardness at the medium stage. Finally, it decreased gradually during further ageing. The maximum value of hardness at was similar with that of the conventional materials and suitable for using as the crown & bridge. 2. During isothermal ageing at a temperature range of $300{\sim}400^{\circ}C$, three phases consisting of the Au-rich ${\alpha}_1$phase with a face-centered cubic structure, the Pt3Zn ${\alpha}_2$phase with an ordered AuCu3(L12) type(f.c.c.) and the Pt-rich ${\alpha}_3$phase with face-centered cubic structure in solution-treated gold alloys were transformed into different three phases consisting of the ${\alpha}_1$phase, the ${\alpha}_3$phase and the PtZn $\beta$phase with an ordered AuCu I(L10) type. 3. The hardening of gold alloys was attributed to the lattice strains of the matrix resulting from the transformation of the ${\alpha}_2$phase to the $\beta$phase. 4. The softening of gold alloys during over-ageing was attributed to the coarsening of the nodules consisting of the $\beta$phase and ${\alpha}_1$matrix.

• Journal of Yeungnam Medical Science
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• v.39 no.4
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• pp.322-331
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• 2022

Background: The combined use of biomaterials for regeneration may have great biological relevance. This study aimed to compare the regenerative potential of biphasic calcium phosphate (BCP) alone and with growth factor enamel matrix derivatives (EMDs) for the regeneration of intrabony defects at 1 year. Methods: This randomized controlled trial included 40 sites in 29 patients with stage II/III periodontitis and 2/3 wall intrabony defects that were treated with BCP alone (control group) or a combination of BCP and EMD (test group). BCP alloplastic bone grafts provide better bio-absorbability and accelerate bone formation. EMDs are commercially available amelogenins. Mean values and standard deviations were calculated for the following parameters: plaque index (PI), papillary bleeding index (PBI), vertical probing pocket depth (V-PPD), vertical clinical attachment level (V-CAL), and radiographic defect depth (RDD). Student paired and unpaired t-tests were used to compare the data from baseline to 12 months for each group and between the groups, respectively. The results were considered statistically significant at p<0.05. Results: At 12 months, the PI and PBI scores of the control and test groups were not significantly different (p>0.05). The mean V-PPD difference, V-CAL gain, and RDD difference were statistically significant in both groups at 12 months (p<0.001 for all parameters). Intergroup comparisons showed that the mean V-PPD reduction (2.13±1.35 mm), V-CAL gain (2.53±1.2 mm), and RDD fill (1.33±1.0 mm) were statistically significant between the groups at 12 months (p<0.001 for all parameters). Conclusion: BCP and EMDs combination is a promising modality for the regeneration of intrabony defects.

• Journal of Technologic Dentistry
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• v.37 no.3
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• pp.131-144
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• 2015

Purpose: This study set out to propose plans for more efficient and effective clinical practice by investigating the current state of clinical practice in the field of dental technology and thus provide basic data to develop pre- and post-education programs for clinical practice. Methods: The subjects include dental technicians at dental technical laboratories that were appointed as the place of clinical practice by the Department of Dental Technology of G University. The survey period spanned from December 22, 2014 to January 20, 2015. Total 250 questionnaires were distributed to them, and 190(76.0%) were returned. After excluding 23 whose answers were uncertain or seemed to lack reliability, total 167(66.8%) were used in final analysis. Results: 1. The most frequent practice the student did during clinical practice was articulator attachment, which was followed by pin operation or model making, one's own task and practice, sand and crow sculpturing, burying, casting, and grinding. 2. In case of going through the entire process, porcelain had the most students at 39(23.4%), being followed by crown & bridge at 28(16.8%), clinical model at 23(13.8%), full denture at 17(10.2%), and partial denture at 17(10.2%) in the order. 3. Of the students, 59.8%(30.5% for reinforced basic practice; 29.3% for intensive practice education) said that intensive practice education should be reinforced in school; and 22.3% said that intensive theory and practice education was needed, which indicates that 82.6% voiced their opinion of reinforcing education around practice. 4. The students felt that they lacked diligence, passion, and theoretical knowledge somewhat and were relatively good at clinical adaptation and operational skills. Conclusion: The findings show that the students felt an absolute lack of practice education as the school education was focused on theory and national exams in the field of dental technology, thus raising a need to reinforce practice education. Of all the respondents, 62.9% said there was a need to improve the current education with a focus on jobs. In future, education of dental technology should work to bring up able dental technicians that can perform in clinical dental technology right after graduation by reinforcing job-based practice education.

• The Journal of the Korean dental association
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• v.12 no.2
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• pp.131-134
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• 1974

The author had studied the masticatory effience on three different types; on missing of the first molar, on replacing the missed first molar with crown & bridge and on natural dentition. This study was made from the parched soybeans as testfood by means of mesh technique. As a result of this study on 25 of natural dentitions, 20 of crown & bridges and 25 of missing of the first molars, the following were come out. 1. Masticatory efficiency of natural dentitions was 75.8%, that of crown & bridges was 66.4%, and that of missing of the first molars was 43.7%. 2. Difference of masticatory efficiency of crown & bridges to natural dentitions was 9.4%, that of natural dentitions to missing teeth was 32.1%, and that of crown & bridges to missing teeth was 22.7%.

• The Journal of the Korean dental association
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• v.21 no.7 s.170
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• pp.579-583
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• 1983

A 58-year old woman with no molar teeth on her upper left side wanted these missing teeth to be replaced with a fixed implant prosthesis. Incision, from distal to 2nd premolar to hamulus, was performed and impression of canine fossa anteriorly, zygoma buccally, pterygoid hamulus posteriorly and palatal groove lingually was taken by Optosil (Bayer Dent.). The implant frame was made of Vitallium, and was inserted the next day after the impression had been taken. 12-days later, the 4-units fixed prosthesis was constructed. The patient was extremely comfortable, had no pain, and was able to chew food more efficiently.