• Journal of Technologic Dentistry
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• v.41 no.2
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• pp.93-100
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• 2019

Purpose: This study is making a dog dental prosthesis using digital dental technology. The mechanical strength of the prosthetic material was observed in terms of compressive strength and fracture pattern. Methods: The experiment was performed using dog mandibular molars. The teeth were scanned and modeled. The specimens were made of zirconia, PMMA and Ni-Cr. The specimens were subjected to a vertical compression test with an artificial cancellous bone in UTM tester. Vertical compressive strength and fracture behavior of specimen were observed. Results: The result of observing the compressive load between specimen and artificial bone were $184.8{\pm}5.7N$ in the zirconia specimen, $185.6{\pm}8.9N$ in the PMMA specimen, and $184.4{\pm}4.0N$ in the Ni-Cr alloy specimen. Compression marks of artificial bones were observed. The fracture strength of specimen was observed. The fracture strength of the zirconia specimen was an average of 1,381.4N. The fracture strength of the PMMA specimen was an average of 572.2N. Conclusion: The crown made of three kinds(zirconia, PMMA, Ni-Cr alloy) of materials has the strength to chew about the artificial bone. zirconia and PMMA have vertical compressive strength applicable to medium dog dental prosthetic materials.

• The Journal of the Korean dental association
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• v.10 no.11
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• pp.773-775
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• 1972

• The Journal of the Korean dental association
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• v.47 no.9
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• pp.567-575
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• 2009

• The Journal of Advanced Prosthodontics
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• v.8 no.5
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• pp.345-353
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• 2016

PURPOSE. The aim of this study was to assess the esthetic outcome of maxillary anterior single implants by comparing the esthetic perception of dental professionals and patients. MATERIALS AND METHODS. Twenty-three patients with single implants in the esthetic zone were enrolled in this study. Dentists of four different dental specialties (Three orthodontists, three oral surgeons, three prosthodontists, and three periodontists) evaluated the pink esthetic score (PES)/white esthetic score (WES) for 23 implant-supported single restorations. The satisfactions of the patients on the esthetic outcome of the treatment have been evaluated according to the visual analog scale (VAS). RESULTS. The mean total PES/WES was $12.26{\pm}4.76$. The mean PES was $6.45{\pm}2.78$ and mean WES was $5.80{\pm}2.82$. There was a statistically significant difference among the different specialties for WES (P<.01) and Total PES/WES (P<.01). Prosthodontists were found to have assigned poorer ratings among the other specialties, while oral surgeons gave the higher ratings than periodontists, orthodontists, and prosthodontists. CONCLUSION. Prosthodontists seemed to be stricter when assessing aesthetic outcome among other specialties. Moreover, a clear correlation existed between dentists' and patients' esthetic perception, thereby providing rationales for involving patients in the treatment plan to achieve higher levels of patient satisfaction.

• Journal of Oral Medicine and Pain
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• v.42 no.4
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• pp.102-108
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• 2017

Purpose: Many metal ions released from dental casting alloys have been reported to influence the intraoral symptoms of oral lichen planus (OLP) and burning mouth syndrome (BMS). The aim of this study was to investigate the relationship between salivary metal ion levels and the prosthetic duration as well as to evaluate the time-dependent morbid effects of metal ions in OLP and BMS patients. Methods: Three study groups consist of the following subjects respectively: 17 OLP patients, 12 BMS patients, and 12 patients without oral symptoms. The salivary concentrations of 13 metal ions (copper, cobalt, zinc, chromium, nickel, aluminum, silver, iron, titanium [Ti], platinum, tin, palladium, and gold) were measured by Laser Ablation Microprobe Inductively coupled Plasma Mass Spectrometry. Results: The Ti ions had statistically significant differences among the groups with a prosthetic duration of less than 5 years. There were no significant differences between all ion levels among the groups wearing dental cast alloys for over 5 years. In the BMS group, the level of Ti ions in patients with prosthetic restorations less than 5 years old were significantly high (p<0.05). Conclusions: In the BMS group, 3-60 months during which salivary Ti levels were higher were matched with the duration of burning symptoms ($15.6{\pm}17.1months$). Furthermore, Ti ions were statistically high in the oral cavity of BMS patients fitted with dental casting alloys for 5 years. These results suggest that Ti ions released from dental implants and oral prostheses could attribute to burning sensation of BMS.

• Journal of dental hygiene science
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• v.18 no.3
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• pp.155-163
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• 2018

This study's aim was to investigate their opinions to improve the educational system for dental hygienists on the basis of their duties as dental hygienists. The qualitative study was conducted among 19 dental hygienists at Daejeon, Korea from July to August 2016. Two researchers followed each subject for working hours in a day and recorded all the tasks and time to take for each task. After one day, the researchers met each subject and conducted face-to-face interviews to investigate the opinions about the dental hygiene curriculum and national board examination. The main duties recognized by more than half of the subjects were oral disease prevention including scaling and dental treatment assistance. The subjects' minority opinion about the main duties included radiography, impression taking, dental implant surgery assistance, orthodontic treatment, patient counseling, dental management and staff management, and oral health education. The most important tasks perceived by the subjects were prosthetic and implant impressions, scaling and implant surgery assistance. The subjects' minority opinion about the most important duties included patient counseling and making temporary crowns. The most difficult tasks answered by the subjects were prosthetic and implant impressions and dental implant surgery assistance. The subjects' minority opinion about it included patient counseling, scaling, and making temporary crowns. They mentioned that their curriculum in college was different from the actual work and the national board examination was not reflective of their real duties. We found out Korean dental hygienists had a lot of roles as dental assistants, dental business managers, and so on. We suggest that the law, curriculum and national board examination for dental hygienists should be revised to be able to reflect the reality of the clinical field.

• The Journal of the Korean dental association
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• v.56 no.9
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• pp.492-502
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• 2018

Anterior maxillary teeth play an important role in determining a person's first impression and facial profile. Implant surgery in esthetic area requires more careful diagnosis, treatment planning, surgery, and prosthetic restoration than in posterior area. To avoid complications in surgery and prosthetic restoration for implants in esthetic area, accurate diagnosis and appropriate case selection become very important. If you have decided to restore the area with implant prosthesis, you have to know exactly where to place an implant. I will discuss the ideal implant position in terms of mesio-distally, apico-coronally, labio-palatally, and implant angulation. And I would like to point out the selection of fixture diameter & length for anterior implant. Finally, a clinical implant prosthesis case in maxillary central incisor will be shown. In conclusion, for superior esthetic outcome in anterior implant prostheses, we must understand the patient's anatomic condition and know our ability.

• The Journal of Advanced Prosthodontics
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• v.10 no.4
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• pp.300-307
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• 2018

PURPOSE. To investigate the fatigue and fracture resistance of computer-aided design and computer-aided manufacturing (CAD/CAM) ceramic molar crowns on dental implants and human teeth. MATERIALS AND METHODS. Molar crowns (n=48; n=8/group) were fabricated of a lithium-disilicate-strengthened lithium aluminosilicate glass ceramic (N). Surfaces were polished (P) or glazed (G). Crowns were tested on human teeth (T) and implant-abutment analogues (I) simulating a chairside (C, crown bonded to abutment) or labside (L, screw channel) procedure for implant groups. Polished/glazed lithium disilicate (E) crowns (n=16) served as reference. Combined thermal cycling and mechanical loading (TC: $3000{\times}5^{\circ}C/3000{\times}55^{\circ}C$; ML: $1.2{\time}10^6$ cycles, 50 N) with antagonistic human molars (groups T) and steatite spheres (groups I) was performed under a chewing simulator. TCML crowns were then analyzed for failures (optical microscopy, SEM) and fracture force was determined. Data were statistically analyzed (Kolmogorow-Smirnov, one-way-ANOVA, post-hoc Bonferroni, ${\alpha}=.05$). RESULTS. All crowns survived TCML and showed small traces of wear. In human teeth groups, fracture forces of N crowns varied between $1214{\pm}293N$ (NPT) and $1324{\pm}498N$ (NGT), differing significantly ($P{\leq}.003$) from the polished reference EPT ($2044{\pm}302N$). Fracture forces in implant groups varied between $934{\pm}154N$ (NGI_L) and $1782{\pm}153N$ (NPI_C), providing higher values for the respective chairside crowns. Differences between polishing and glazing were not significant ($P{\geq}.066$) between crowns of identical materials and abutment support. CONCLUSION. Fracture resistance was influenced by the ceramic material, and partly by the tooth or implant situation and the clinical procedure (chairside/labside). Type of surface finish (polishing/glazing) had no significant influence. Clinical survival of the new glass ceramic may be comparable to lithium disilicate.

• The Journal of the Korean dental association
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• v.47 no.9
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• pp.585-595
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• 2009

Purpose : The aim of this study was to compare surgical complications between simple implant placement and implant placement combined with complicated surgical procedures. We also evaluated prosthetic complications according to the specific types of prosthesis. Material and Method : A retrospective analysis of dental chart of patients who was performed implant therapy during the period from June 2003 to December 2005 was carried out. This study was performed on 408 patients (208 male, 200 female). In addition, 1671 implants were performed. Based on their medical record and radiographs, the authors evaluated surgical and prosthetic complications, surgical procedures accompanied at the time of implant, risk factors of implant failure etc. Result : Surgical complications were developed on 358 implants(21.4% on total placed implants) and wound dehiscence was most prevalent complication. On maxillary posterior area, surgical complications developed more frequently on implants with major surgery and showed a significant difference. And complication rate of implants accompanied with GBR was higher than that of simple implants placement and also showed significant difference. The implant supported prosthesis showed no statistical difference in the occurrence of complications according to the types of prosthesis, and food retention was the most common post-prosthetic complication. Also we speculated that length and width of implant showed significant correlation to the failure of implant primary osseointegration. Conclusion : Based on the result, clinician should provide more careful maintenance for patients with implant placement accompanied by complicated surgical procedure. And periodic maintenance for the patient is requested for long-term survival of implant therapy.

• The Journal of Advanced Prosthodontics
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• v.4 no.4
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• pp.192-196
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• 2012

PURPOSE. The purpose of this study was to evaluate the effect of provisional cement removal by different dentin cleaning protocols (dental explorer, pumice, cleaning bur, Er:YAG laser) on the shear bond strength between ceramic and dentin. MATERIALS AND METHODS. In total, 36 caries-free unrestored human third molars were selected as tooth specimens. Provisional restorations were fabricated and cemented with eugenol-free provisional cement. Then, disc-shaped ceramic specimens were fabricated and randomly assigned to four groups of dentin cleaning protocols (n = 9). Group 1 (control): Provisional cements were mechanically removed with a dental explorer. Group 2: The dentin surfaces were treated with a cleaning brush with pumice Group 3: The dentin surfaces were treated with a cleaning bur. Group 4: The provisional cements were removed by an Er:YAG laser. Self-adhesive luting cement was used to bond ceramic discs to dentin surfaces. Shear bond strength (SBS) was measured using a universal testing machine at a 0.05 mm/min crosshead speed. The data were analyzed using a Kolmogorov Smirnov, One-way ANOVA and Tukey HSD tests to perform multiple comparisons (${\alpha}$=0.05). RESULTS. The dentin cleaning methods did not significantly affect the SBS of ceramic discs to dentin as follows: dental explorer, pumice, cleaning bur, and Er:YAG laser. CONCLUSION. The use of different cleaning protocols did not affect the SBS between dentin and ceramic surfaces.