• Journal of Technologic Dentistry
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• v.34 no.4
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• pp.337-344
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• 2012

Purpose: This study examined the corrosion level by alloy type and pH, and used the corrosion levels as the dental health data. The study utilized one Ni-Cr alloy for the full and removable partial denture metal frameworks and two Ni-Cr alloys for porcelain-fused-to-metal crown, among the non-beryllium dental casting non-precious Ni-Cr alloys. Methods: The alloy specimens were manufactured in $10cm^2$ and stored in the corrosive solution(pH 2.2-4.4) in the electrical water bath($37^{\circ}C$) for seven days. Afterwards, the metal ions were quantitatively analyzed using the ICP. Results: Of the three metal alloys, Bellabond-Plus$^{(R)}$alloy and SOLIBOND N$^{(R)}$alloy, with 22% or higher chrome chemical contents, had higher corrosion resistance than Jdium-100$^{(R)}$alloy with 20% chrome chemical content. In all three alloys, the corrosion of Ni was highest, and metal ion corrosion was higher in the pH 2.2 corrosive solution. Conclusion: Although Ni-Cr alloy was not very corrosive, a Ni-allergic patient should not have Ni-Cr alloy prosthesis. The Ni-Cr alloy for porcelain-fused-to-metal crown should be designed for the dental porcelain to cover the whole crown.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.2
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• pp.1-16
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• 1991

In order to see the possible effect of the functional load-bearing after osseointegration of the titanium root form implant in dog a histologic study was conducted. One side of lower jaw was surgically prepared edentulousness and titanium implants were inserted. Some implants were functionally loaded through fixed detachable prosthesis and some are isolated and unloaded. The dog was sacrificed four months later and bone sections with implants were processed for histologic evaluation and the results were as follows ; (1) The bone to implant interface after four months of load bearing presented no mobility and no marginal bone loss radiographically and histologically. (2) The interface zone between compact bone and implant revealed a direct bone to implant contact and in some areas marrow tissue contacts were examined at the light microscopic level. (3) At the ultrastructural level the interface of surrounding compact bone matrix and implant, three types of superficial layers were found ; one with moderate electron dense amorphous granular substance layer, other with high electron dense fine granular substance layer, and another type of amorphous granular substance covered with high electron dense line of minute granules. (4) The osteoblasts in the marrow tissue neighboring implants and osteocytes in compact bone showed typical normal characteristics and in the marrow tissues some of lymphocytes and mast cells were observed. (5) The abscence of abnormal tissue reactions at a cellular level indicates a high degree of biocompatibility for the experimental titanium implant and basically no difference was found between functionally loaded and unloaded implants.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.2
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• pp.167-171
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• 2016

Patients undergone partial maxillectomy experience post-operative masticatory, phonetic, and swallowing difficulties. They also encounter social and psychological challenges due to changes in their facial appearances. Thus, functional and esthetic recovery through maxillofacial prosthesis becomes significant for these patients. The objective of an appropriate obturator is to restore palate and improve phonetic and swallowing ability by separating the oral cavity, nasal cavity, maxillary sinus, and nasopharynx. In this case report, an obturator was fabricated for a patient who had partial resection from the maxillary posterior region to the pharynx due to squamous cell carcinoma. The purpose of this case study is to describe the results because the patient was successfully improved both functionally and esthetically.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.5
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• pp.579-588
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• 2007

Statement of problem: A tenderness of the dentin after tapering of teeth for dental prosthesis is a common phenomenon. In practice, the alternative desensitizer may be used for minor pain after tapering of teeth. Purpose: In this study, the desensitizers were used to investigate the affect decreasing of shear bond strength according to the use of various cement, such as resin, Glass Ionomer, and phosphate cement. Material and method: Three different desensitizers were used on this study Compositions of two dentin desensitizers were HEMA(hydroxyethylmethacrylate) and glutaraldehyde. The other one is oxalic acid. Three dentin desensitizers applied on 12 degrees taper teeth. Then, Ni-Cr crowns were bonded with Resin cement, Zinc Phosphate (ZPC) cement and Glass Ionomer (GIC) cement. 120 human premolar teeth were used for specimens. The specimens were divided into four group as the reference and the empirical each with thirty specimens, then further divided into 12 group according to type of desensitizers and cement types. The shear bond strength were measured by Instron multi task instrument. Results: According to the result, the measured shear bond strength in order from the weakest to the strongest in general was ZPC, Resin, and GIC. And it is found that the application of desensitizers on dentin surface does not affect the shear bond strength. Conclusion: Dentin desensitizers that alleviate or prevent a dentin tenderness, usually contains HEMA and glutaraldehyde compounds. Such desensitizers are widely used in clinical studies. By applying the dentin desensitizer on the exposed dentin surface, the dentin capillary are blocked and periodontal membrane and cementum can not be drawn in pulp cavity. Since HEMA and glutaraldehyde may cause harm to the pulp cavity, an alternative desensitizer was developed.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.6
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• pp.590-596
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• 2002

The resin : metal interface is at the basis of most bonding failures in resin-bonded prosthesis. Although debonding has been a problem with adhesive fixed partial dentures, various dentists classify them as long-term restorations. The advantages of resin-bonded fixed partial dentures include minimal tooth reduction and the possibility of rebonding. if resin-bonded protheses can be easily rebounded, it is of clinical importance to know if the lutingagents rebond as well the second time as they did originally. Several retentive systems for resin-to-metal bonding have recommended. Treatments such as electrolytic etching and silicone coating, despite the good result of bond strength, have proved to be time-consuming and technique-sensitive. Therefore a simple and more reliable method is desirable. This study evaluated the effect of metal surface treatments on the rebond strength of panavia 21 cement to a nickel-chromium(Ni-Cr) alloy. The samples were received the following surface treatments : Group No.1 (control or served as the control) treatment with sandblasting with 50um aluminum oxide and ultrasonically cleaned for 10minutes in double-deionized water, Group No.2 were no surface treatments. Group No.3 were treated with metal primer. Group No.4 were treated with sandblasting as previously described, and then metal priming. From the analysis of the results, the following conclusions were drawn. 1. Sandblasting and metal priming appears to be an effective method for treatment of metal after accidental debonding. 2. Group without surface treatment had significantly lower bond strengths compared with other groups. 3. The combination of sandblasting and metal priming may not develop superior bonding strengths compared with other techniques that used the Ni-Cr alloys. 4. Combination of cohesive and adhesive failures were the most common type observed. The results support the use of sandblasting as a viable procedure when rebonding accidentally lost adhesive partial denture. We concluded that sandblasting and metal priming of metal surface before bonding could provide the adequate bond strength during rebonding of resin-bonded fixed partial denture.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.4
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• pp.544-551
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• 2000

A fabrication method of inner and outer crown using CAD/CAM is presented. The information of abutment teeth is transferred to a computer through a 3-dimensional scanner. A Konus inner and outer crown is designed on a computer and a real crown is machined based on this design using CAM. This method can save laboratory time and reduce inaccuracies compare to conventional casting procedure. A stone model with six prepared abutment teeth from a patient was used in this study. Three dimensional information from the model was transferred to a computer using a contact type 3-dimensional scanner with a $25{\mu}m$ accuracy. All margins were identified on a computer image where there is a change in surface taper of a model. To provide a cement space, the image of a inner sur face of a Konus inner crown was duplicated $25{\mu}m$ apart from the surface of a prepared abutment teeth image. The cement space was $20{\mu}m$ at the cervical margin. All Konus crowns were machined with a $10{\mu}m$ accuracy. It was concluded that this method can reduce working-time for the laboratory process and increase accuracy. A further research is required to make a simplified process for a more complex prosthesis.

• The Journal of Advanced Prosthodontics
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• v.4 no.4
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• pp.204-209
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• 2012

PURPOSE. The aim of this systematic review is to address treatment outcomes of Mandibular implant overdentures relative to implant survival rate, maintenance and complications, and patient satisfaction. MATERIALS AND METHODS. A systematic literature search was conducted by a PubMed search strategy and hand-searching of relevant journals from included studies. Randomized Clinical Trials (RCT) and comparative clinical trial studies on mandibular implant overdentures until August, 2010 were selected. Eleven studies from 1098 studies were finally selected and data were analyzed relative to number of implants. RESULTS. Six studies presented the data of the implant survival rate which ranged from 95% to 100% for 2 and 4 implant group and from 81.8% to 96.1% for 1 and 2 implant group. One study, which statistically compared implant survival rate showed no significant differences relative to the number of implants. The most common type of prosthetic maintenance and complications were replacement or reattaching of loose clips for 2 and 4 implant group, and denture repair due to the fracture around an implant for 1 and 2 implant groups. Most studies showed no significant differences in the rate of prosthetic maintenance and complication, and patient satisfaction regardless the number of implants. CONCLUSION. The implant survival rate of mandibular overdentures is high regardless of the number of implants. Denture maintenance is likely not inflenced substantially by the number of implants and patient satisfaction is typically high again regardless os the number of implants.

• The Journal of Advanced Prosthodontics
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• v.4 no.4
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• pp.197-203
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• 2012

PURPOSE. The aim of this systematic review was to address treatment outcome according to attachment systems for mandibular implant overdentures in terms of implant survival rate, prosthetic maintenance and complications, and patient satisfaction. MATERIALS AND METHODS. A systematic literature search was conducted using PubMed and hand searching of relevant journals considering inclusion and exclusion criteria. Clinical trial studies on mandibular implant overdentures until August, 2010 were selected if more than one type of overdenture attachment was reported. Twenty four studies from 1098 studies were finally included and the data on implant survival rate, prosthetic maintenance and complications, patient satisfaction were analyzed relative to attachment systems. RESULTS. Four studies presented implant survival rates (95.8 - 97.5% for bar, 96.2 - 100% for ball, 91.7% for magnet) according to attachment system. Ten other studies presented an implant survival rate ranging from 93.3% to 100% without respect to the attachment groups. Common prosthetic maintenance and complications were replacement of an assay for magnet attachments, and activation of a matrix or clip for ball or bar attachments. Prosthetic maintenance and complications most commonly occurred in the magnet groups. Conflicting findings were found on the rate of prosthetic maintenance and complications comparing ball and bar attachments. Most studies showed no significant differences in patient satisfaction depending upon attachment systems. CONCLUSION. The implant survival rate of mandibular overdentures seemed to be high regardless attachment systems. The prosthetic maintenance and complications may be influenced by attachment systems. However patient satisfaction may be independent of the attachment system.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.3
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• pp.268-274
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• 2020

Functional and esthetic recovery through reconstruction of the oral and maxillofacial system is important for patients who underwent mandibulectomy due to lesions such as oral cancer. The fibula free flap, which is frequently used in the reconstruction of the mandible, is easy to prosthetic restoration with implant placement. However, patients with growing periods have difficulty in treatment with implants when the size of the fibula is small and residual growth remains. This case is an 11-year-old female patient who underwent mandibulectomy due to osteosarcoma and reconstruction of the mandible using a fibular free flap. Functional and esthetic recovery were obtained through prosthetic restoration using implant-supported fixed prostheses. Implantation site, number of implants, and type of prostheses were considered. Implant-supported fixed prostheses were delivered at 13 years old, and after an additional 1 year observation, stable results were obtained. However, observing changes in the maxillofacial system through further examinations is necessary.

• Journal of Yeungnam Medical Science
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• v.31 no.2
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• pp.113-116
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• 2014

A 52-year-old man was referred to our hospital due to fever and myalgia that occurred 2 weeks earlier. He showed a complete atrioventricular block on his electrocardiogram, and his vital signs were unstable. On his transthoracic echocardiograph, the 1.5 cm vegetation in the aortic valve with severe aortic regurgitation suggested infective endocarditis. His transesophageal enchocardiograph showed abscess in his mitral-aortic intervalvular fibrosa and vegetation was suspected on his anterior mitral valve leaflet. The patient underwent an emergent operation for valve replacement with temporary epicardial pacing. Intraoperatively, the septal leaflet of his tricuspid valve was injured during the debridement of the abscess pocket that was extended to the membranous septum. The aortic, mitral, and tricuspid mechanical valves were replaced with annular reconstruction without complications. After 14 days of intravenous antibiotics, we successfully changed the epicardial pacemaker into a transvenous DDD-type permanent pacemaker by placing a left ventricular lead via the coronary sinus and an atrial lead in the right atrium appendage. The patient was discharged in a tolerable state and was examined uneventfully in our hospital's outpatient clinic for 8 months.