• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.13.1-13.6
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• 2020

Background: The aim of this study was to evaluate the factors that may affect implant fixture fractures. Methods: Patients who experienced implant fixture removal at Seoul National University Bundang Hospital from 2007 to 2015 due to implant fixture fracture were included. Implant/crown ratio, time of implant fracture, clinical symptoms before implant fracture, treatment of fractured implants, and the success and survival rate of the replaced implants were evaluated retrospectively. Results: Thirteen implants were fractured in 12 patients. Patient mean age at the time of fracture was 59.3 years. Of the 13 implants, 7 implants were placed at our hospital, and 6 were placed at a local clinic. The mean crown/implant ratio was 0.83:1. The clinical symptoms before fracture were screw loosening in five implants, marginal bone loss in five implants, and the presence of peri-implant diseases in five implants. All the fractured implants were removed, and 12 out of the 13 sites were re-implanted. Parafunctions were observed in two patients: one with bruxism and one with attrition due to a strong chewing habit. Conclusions: Several clinical symptoms before the fracture of an implant can predict implant fixture failure. Therefore, if these clinical symptoms are observed, appropriate treatments can be taken before more serious complications result.

• Journal of Oral Medicine and Pain
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• v.20 no.2
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• pp.317-325
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• 1995

This study was performed to investigate the mean life expectancy of dental prosthetic restorations. The author has examined 352 dental prosthesis clinically and radiologically, and decided the success(survival) and failure(mortality) of the dental prosthesis. The dental prosthesis which had been treated in the Seoul National University Dental Hospital, two private clinics in Seoul, one university dental hospital, and two private clinics in local province were included in this study. The survival analysis using product limit estimator was used and the mean life expectancy of each type of dental prosthesis was calculated. The results were as follows : 1. The life expectancies were 10.5 years in gold crown and bridge, 8.5 years in porcelain fused to metal crown and bridge, 8.3 years in nonprecious metal crown and bridge, 8.1 years in removal partial denture, and 7.7 years in full denture. 2. The causes of mortality were in the order of dental caries(24.6%), fracture of dental prosthesis(19.2%), periodontal problems(18.6%), chronic chewing difficulty and dysfunction due to dental prosthesis(15.0%), excessive exposure of abutments due to the marginal defect of dental prosthesis(14.4%), abnormal occlusion due to severe attrition of artificial teeth in dentures(3.0%), periapical problems(2.4%), perforation of dental prosthesis(1.8%), and loose contacts with neighboring tooth(1.2%). 3. Among survival cases, 66.5% showed normal chewing ability and 31.9% showed partial chewing ability. However, 1.6% of them complained loss of chewing ability. 4. Among failure cases, 6.6% showed normal chewing ability and 38.9% showed partial chewing ability. However, 54.5% of them complained loss of chewing ability.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.4
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• pp.781-787
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• 1997

In spite of the improvements of the techniques in the field of preventive dentistry, many children still present with extensive destruction of primary anterior teeth. Not only the practioner must consider the pulp state of the primary incisor, but also restore the form, function and esthetics of the tooth. Restorative treatment of primary incisor tooth requires durability, retention and esthetics. Stainless steel crowns used in restoring primary anterior teeth is retentive and durable in comparison with the composite resin, celluloid crown. But they are not esthetic. To enhance the esthetics of the anterior stainless steel crown without reducing its superior retention, an open-face stainless steel crown has been suggested. Several authors have suggested cutting away the labial portion of the stainless steel crown and placing the composite resin in that area. By following this technique, the practioner can prepare a retentive, durable, and esthetic restoration for primary teeth which have suffered from extensive loss of teeth structure. In addition, the single missing primary anterior teeth can be successfully restored by soldering the stainless steel crown together. Open-face stainless steel crown is indicated in the areas of large interproximal lesions involving incisal edge, crown fracture with pulp exposure and congenital malformation of the teeth. By this technique, the practioner can restore primary anterior teeth successfully regardless of the amount of remaining tooth structure, bruxism habit and presence of attrition. In this case, rampant caries with extensive loss of tooth structure and single missing of primary anterior tooth hart been successfully treated with open-face stainless steel crown.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.91-99
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• 2022

Severely worn dentition causes various complications such as loss of tooth structure, discoloration, pulp complications and loss of function and aesthetics. In this case, the patient showed particularly severe attrition in the anterior teeth and lack of space for restoration. The amount of vertical dimension was determined based on the diagnostic wax up, and the patient's adaptation was evaluated by using a removable occlusal splint for 6 weeks. Thereafter, the coordination of the muscular nervous system, aesthetics, temporomandibular joint were re-evaluated for 3 months by restoring the fixed provisional restoration. Through the above treatment process, the final restoration was completed with full mouth fixed prosthesis using monolithic zirconia, and functionally and aesthetically stable results were obtained.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.2
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• pp.119-124
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• 2013

Many of the patients with extensive abrasion need comprehensive restorative treatment. The abrasion is usually caused by attrition, besides of it, there are many reasons for it. The plan of treatment should be started on assessment of the type of attrition and the etiologic analysis. Patient with well-developed masticatory muscle, alveolar process, and high occlusal force and also with little muscle length difference between the stable and the contracted state should be carefully assessed for the vertical dimensional loss and the restoration should be carefully designed. Decrease of tooth length can be compensated by the growth of the alveolar bone height; therefore, consistency of the occlusal vertical dimension is maintained. Accordingly, a careless increase of the vertical dimension can produce muscle fatigue, depressed tooth and pain, and fracture of the restoration. In this case, the patient with multiple tooth abrasion and clenching habit, the edentulous maxillary area is restored with amalgam inserted RPD, and the dentulous area of the maxilla and mandible are treated with fixed restoration accompanying with the increase of vertical dimension. Consequently, we are going to report about the satisfying result in both functional and esthetic aspects.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.3
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• pp.243-249
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• 2018

Excessive tooth wear results in unacceptable damage to the occlusal surface and can cause pulpitis, occlusal disharmony, dysfunction, and unesthetic result. Patients with severe attrition have to be classified as several types relative to the vertical dimension of occlusion (VDO) and the interocclusal distance for the prosthetic space. The patient in this case was a 80 - year - old woman who lost support of posterior occlusion and collapsed of the occlusal plane due to confrontation of the opposing teeth, accompanied by an increase in the number of remaining bristles, resulting in a loss of intermaxillary space for prosthesis. In this case, treatment with increased vertical dimension may have stability if the increase in vertical occlusal height is minimized within the required range, and a stable occlusal contact is provided after an increased vertical occlusal height stabilization period. After the new VDO had been confirmed under interim fixed restorations, definitive fixed restorations were produced. Through these treatment processes, we obtain satisfactory results that are functional and aesthetically pleasing.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.1
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• pp.21-33
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• 2007

Statement of problem: The esthetic component of dental care has become increasingly more important, while new tooth-colored materials are continually marketed. Various new indirect composite materials have been developed with required advantages. The most recent development in the indirect composites has been the introduction of the second-generation laboratory composite or poly-glass materials. They are processed by different laboratory techniques based on combinations of heat, pressure, vacuum and light polymerization. Although, second generation products became available in 1995, their characteristics and clinical performance have not been adequately investigated. Purpose: The aim of this study was to measure the mechanical properties of the second generation indirect resin system and compare these with an existing universal direct composite resin. Material and method: In this study four indirect composite material (Adoro LC, BelleGlass HP, Tescera, Synfony) were tested for flexural strength, wear resistance, hardness and their degree of conversion against Z250, a light cure direct composite. Results: Within the limitations of this study, the following conclusions were drawn: 1. From the abrasion wear result, Adoro showed the least volume loss while Synfony showed the greatest volume loss. Z250 and BelleGlass HP didn't show significant difference (p>0.05), but they showed significant difference with other groups (p<0.05). From the attrition wear, BelleGlass HP showed the least volume loss and it didn’t show significant difference with Tescera (p>0.05). While Synfony showed the greatest volume loss that it showed significant difference with other groups (p>0.05). 2. Mean values of flexural strength by means of three point bending test was in the order of Z250, Adoro, Belleglass HP, Tescera and Synfony. Mean elastic modulus was in the order of Z250, BelleGlass HP, Tescera, Adoro and Synfony. 3. The result of Vicker‘s microhardness value showed that significantly higher value in Z250 (p<0.05), and is in the order of BelleGlass HP, Tescera, Adoro and Synfony. 4. The degree of conversion measured by FT-IR showed significantly higher value in BelleGlass HP (p<0.05), and is in the order of Adoro, Synfony, Tescera and Z250. Conclusion: Significant differences were found in the flexural strength, wear resistance, hardness and their degree of conversion.

• Journal of the Korean Ceramic Society
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• v.39 no.5
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• pp.438-445
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• 2002

In this study, the glass frit of $PbO-TiO-2-SiO_2-BaO-ZnO-Al_2O-3-CaO-B_2O_3-Bi_2O_3-MgO$ system was manufactured. The glass was melted at $1,400{\circ}C$, quenched and attrition-milled. The glass frit powder was pressed and fired for 2h at the range of $750~1,000{\circ}C$. The crystallization of glass frit began at about $750{\circ}$ and at low temperature, the main crystal phases were hexagonal celsian($BaAl_2Si_2O_8$) and alumina. As the firing temperature increased, the crystal phases of monoclinic celsian, zinc aluminate, zinc silicate, calcium titanium silicate and titania appeared. And the increase of firing temperature led to transformation of hexagonal celsian to monoclinic. The only glass frit containing 15wt% PbO had the crystal phase of solid solution of $PbTiO_3-CaTiO_3$. At the frequency of 1 MHz, the dielectric constant of glass frit crystallized was in the range of 11~16 and the dielectric loss less than 0.020. But the glass frit containing 15wt% PbO had the dielectric constant of 17~26 and loss of 0.010~0.015 because of crystal phase of solid solution of $PbTiO_3-CaTiO_3$.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.2
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• pp.261-270
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• 2001

This study was performed to evaluate wear characteristics of light-cured composites when opposed by human enamel. Seven light-cured restorative composites were selected and enamel cusps sectioned from premolars. All samples were stored in distilled water at $37^{\circ}C$ for 10 days. 68.6 N of weight was loaded during the test. The measurements of vertical loss of enamel cusps, weight loss and volume loss of composites, and SEM observations of the polished and abraded surfaces were made after 30,000 cycles. The results obtained were summarized as follows; 1. The highest hardness value of 70.4 was observed in the Spectrum group and the lowest value of 19.8 was observed in the Heliomolar group. Results of Tukey test showed that an overall significant difference was indicated except the Spectrum, Z100 and Clearfil AP-X groups(p<0.05). 2. Enamel showed the good abrasion resistance against the Heliomolar group of microfilled composite and the Palpique Toughwell group containing the submicron hybrid type spherical fillers. 3. The abrasive wear resistance of hybrid composites was improved with the decrease of mean particle size and hybrid of submicron particle fillers. 4. SEM observation of worn surfaces revealed the protrusion, attrition and missing of fillers, cracks developing and delamination in the matrix.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.3
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• pp.492-498
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• 1999

Oculodentodigital syndrome(ODD) was first reported by Lohmann in 1920 and termed by Meyer Schwicketath, which they called "dysplasia oculo-dento-digitalis" in 1957. It is somewhat rare heritable disease. ODD is generally inherited in an autosomal dominant pattern with a complex phenotype. The characteristic features are : (1) unique facial features, (2) microphthalmos, (3) syndactyly and camptodactyly of 4th and 5th fingers, (4) osseous anomalies of the middle phalanges of 5th fingers and toes, (5) enamel hypoplasia, (6) dry lusterless hair. We found several occlusal wearing and yellow discoloration of succedaneous teeth, multiple caries lesions, premature loss and pulpal involvement of primary teeth with associated enamel abnormalities caused by generalized enamel hypoplasia in a fairly constant oral finding. Occasionally partial anodontia, microdontia and cleft lip and palate can be manifested. This case, a 9-year-old female with repaired bilateral syndactyly was referred to pediatric dental clinic, Pusan National University Hospital for evaluation of severe attrition of teeth and caries lesions. She had most of the above mentioned typical manifestations of the syndrome. Dental treatment including caries control, stainless steel crown were performed.