• The Journal of the Korean dental association
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• v.19 no.2 s.141
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• pp.159-162
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• 1981

The author devised a simple technique for duplicating occlusal contour of natural teeth on the prepared abutments using hard stone index obtained from the study cast of natural teeth. Throughout this author devised method, the following advantages are studied. Firstly the dentist can obtain an ideal occlusal wax patterns which have arrived at the physiologic state through a long period of adjustment to various habits and functional movements. Secondly the construction procedure is simple, and thirdly it is easy to adjust wax pattern of nomal natural teeth which duplication is required.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.4
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• pp.498-510
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• 2005

Purpose: The purpose of this study was to compare the maximum occlusal force implant prostheses to natural teeth. Material and Method: Fifty nine patients treated either with $Br{\aa}anemark$ implants and ITI implants during the recent ten years were involved in this study. The maximum occlusal force were measured with unilateral bite force recorder and dental prescale system. Results: 1. The maximum occlusal forces of the implant prostheses and natural teeth were not significantly different where measured with unilateral bite force recorder and dental prescale system. 2. The maximum occlusal forces were not significantly different between $Br{\aa}nemark$ implant and ITI implant prostheses. 3. The maximum occlusal forces of the implant prostheses had lower when compared with natural teeth during 1-6 months functional periods when measured with the unilareral bite force recorder(P<0.05) and 1-12 months functional periods when measured with the dental prescale system(P<0.05). After these periods there was not statistical significant difference between the implant prostheses and natural teeth. 4. The maximum occlusal forces of the wide diameter implant prostheses were higher than the maximum occlusal forces of the regular diameter implant prostheses when measured with dental prescale system(P<0.05), but there was no significant difference between the wide diameter and the regular diameter implant prostheses when measured with unilateral bite force recorder. 5. The maximum occlusal forces of the single implant prostheses were not significantly different with the splinting implants prostheses. 6. The maximum occlusal forces of the implant prostheses were not significantly different by age and sex. 7. There was significantly different between maximum occlusal forces measured with unilateral bite force recorder and dental prescale system(P<0.0001) but there was positive correlation(r=0.52. P<0.05). Conclusion: The maximum occlusal forces of the implant prostheses were not significantly different to natural teeth during clenching and unilateral maximum biting.

• Journal of Dental Rehabilitation and Applied Science
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• v.16 no.2
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• pp.133-147
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• 2000

A well-planned, precise occlusal adjustment of natural teeth has some distinct advantages over other forms of occlusal therapy. It should be emphasized, however, that an occlusal adjustment is an irreversible procedure and has definite contraindications in some mouths. Generally, the treatment methods for the patients that has open-bite will be following as below. : (1) Use of removable orthopedic repositioning appliance, (2) Orthodontics, (3) Full or partial reconstruction of the dentition, (4) Orthognathic surgical procedure, (5) Occlusal adjustment of the existing natural teeth, (6) Any combination of the above. Above all, the advantages of occlusal adjustment of natural teeth are : (1) the patient is more able to adapt to the changes in jaw position and posture; (2) the phonetic or speaking ability of the patient is not significantly changed and usually is improved; (3) the esthetics of the natural teeth is not altered and often is better; (4) the hygiene of the individual teeth is easily maintained; and (5) the functional usage of the teeth as cutting and chewing devices is markedly improved. The objective of an occlusal adjustment, as with any form of occlusal therapy, is to correct or remove the occlusal interferences, or premature contacts, on the occluding parts of the teeth which prevent a centric relation closure of the mandible. A systematic, disciplined approach can be followed in treatment, the objectives should be listed. They are : (1) Centric relation occlusion of the posterior teeth. (2) Proper "coupling" of the anterior teeth. (3) An acceptable disclusive angle of the anterior teeth in harmony with the condylar movement patterns. (4) Stability of the corrected occlusion. (5) Resolution of the related symptoms. For the patient with open-bite on anterior and posterior teeth, this case report shows the treatment methods in combination the fixed prosthesis with the selective cutting of the natural teeth. Occlusal adjustment is no longer an elective procedure but a mandatory one for patients requiring restorations and those in treatment for TMD dysfunctions or those whose dentitions show signs of occlusal trauma. Occlusal adjustment is essential for all who do not display the above lists.

• Restorative Dentistry and Endodontics
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• v.26 no.2
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• pp.180-187
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• 2001

The structure of current guides is largely illogical and without any rational use of color ordering. The shade guides are generally made of plastic (rather than the actual composite material) and do not accurately depict the true shade. translucency. or opacity of the composite resin after polymerization. To solve this problem, information based on evaluations of natural teeth and material that use the same method and experimental conditions is necessary. The present investigation measured the color of natural maxillary anterior teeth in vivo and compared the results with those of composite resins. 269 Korean subjects were selected for this study. Intact central incisor. lateral incisor. and canine were selected. The clinical crowns were free of caries or restorations. The middle site of the coronal portion on the labial surface of the tooth was measured by Chroma Meter. The five light activated. resin-based materials (Amelogen, Denfil, Elitefil, Spectrum, Z100) were used in this study. Resin composite was condensed into plastic mold with a diameter of 8mm and a thickness of 4mm. pressed between glass plates to flatten the surfaces. and polymerized using a Visilux II visible light activation unit. The surfaces were polished sequentially on wet sandpaper. Color measurements of each specimen were accomplished by Chroma Meter. A computer program that compares each tooth color with each composite resin color was written and the minimum CIELAB color difference ($\Delta$E$^*$) between tooth and each material was calculated. Under the conditions of this study: 1. Teeth tend to become darker with advancing age. 2. Canines were darker. more yellow. and less green than incisors. 3. The teeth from the women were lighter. more green. and less yellow than the male teeth. 4. In general. composite resins were lighter. more green. and less yellow than teeth. Deficiencies were noted in Hues in YR range. 5. Mean color differences between the five composite resin products and teeth were detectable to the naked eye($\Delta$E$^*$>1.0). 6. In comparing the mean $\Delta$E$^*$ values of materials. Spectrum showed the least followed by Z100, Elitefil, Amelogen, Denfil in increasing order.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.4
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• pp.443-457
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• 2004

Purpose: The purpose of this study was to analyze and estimate whether each company may produce the color of artificial teeth as it stands, in the standard of vita classical shade guide using ShadeScan$^{TM}$ System. Material and methods: we chose the products of 6 companies -EFUCERA, IVOCLAR, ENDURA, TRUBYTE, DURADENT, and DURACROSS- estimated the shade value of each fixed point(cervical, body, and incisal area) of artificial tooth, and verified the equality among the samples from the same company. Results: First, the variation appeared significant at cervical and incisal area. It means that there were significant differences between cervical and incisal area although the most similar artificial teeth to the patients’natural teeth were provided. Second, the results in the body area showed that the variation between artificial and natural teeth was finite(p<0.05) in that area. Conclusion: it shows that the reproduction of colors of artificial teeth might be successful regarding the body is the most important part for a determination of the color of artificial teeth. However, more complements are necessary for the better reproduction of the color of artificial teeth between cervical and incisal area.

• 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.

• The Journal of Korean Academy of Prosthodontics
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• v.19 no.1
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• pp.47-54
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• 1981

Dental porcelains are widely used for restorative material because of its excellent esthetic property. But according to contact with natural teeth or metal in oral cavity, the porcelain may be worn and may effect on masticatory physiology and prosthetic function. The purpose of this experiment was to study on wear of porcelain surface which treated in different method. Using the abrasion device which was designed and constructed by myself, the different porcelain surface were abraded by gold alloy, nickel-chrome alloy and natural teeth in order to compare roughness. Results were as follows. 1. The group of porcelain abraded by gold alloy showed less surface roughness change (t=2.92, p<0.05), and the group of porcelain abraded by natural teeth had high surface roughness. change (t=6.84, p<0.05). 2. According to the method of surface treatment, the surface roughness were very significant (F=9.12, p<0.05). 3. After abrading, the porcelain surface roughness change was very significant (F=54.49, p<0.05). 4. There was no significant between surface treatment method and the kind of abrading materials. (F=1.01, p>0..05). 5. The group of natural glazing had the most smooth surface ($2.1{\pm}1.13{\mu}m$).

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.1
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• pp.23-41
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• 1999

During the previous several decades the osseointegrated implants have been considered as the most ideal therapy for the fully edentulous or partially edentulous patients. Although the research on the biocompatibility of osseointegration, the oral tactile function, and the histo-neurologic study had been performed, the change of the oral tactile sensibility and maximal occlusal force according to the postinsertion time of implant prostheses has not been studied. The purpose of this study was to compare the oral tactile sensibility and maximal occlusal force of implant pros-theses to natural teeth according to the specific postinsertion time intervals. The fifty seven patients treated with $Br{\aa}nemark$ implants during the recent seven years were involved in this study. The oral tactile sensibility and maximal occlusal force were measured according to the postinsertion time (${\leqq}6\;months,\;{\leqq}12\;{\leqq}\;18\;months\;{\leqq}\;24\;months,\;and\;{\geqq}20\;months$) 1. The passive tactile threshold of implants was higher than 6-7 times when comparing to natural teeth(P<0.05) 2. The absolute pressure threshold in horizontal and vertical direction for the passive tactile sensibility had decreased significantly in the post insertion time 13-18 months group and had increased significantly in the post insertion time over 25 months group (P<0.05) 3. 50% limit thickness and 100% absolute thickness for the active tactile sensibility had decreased significantly in the postinsertion time 7-12 months group ($AT_{50}:P<0.005,\;AT_{100}:P<0.05$) 4. The maximal occlusal force of the implants prostheses had decreased when comparing with natural teeth in the postinsertion time 1-6 months group(P<0.05) and after that there was no significant difference between the implant prostheses and natural teeth(P<0.05) 5. Maximal occlusal force according to the postinsertion time had increased significantly in the 13-18 months group (P<0.05) after that there was no significant difference. 6. There was positive correlation between age and oral tactile sensibility tested in horizontal and vertical direction ($P_{H:r}=0.39,\;P_{v:r}=0.41$) and there was no correlation between age and maximal occlusal force, age and active tactile sensibility 7. According to the results or the questionnaire, 76.6% of the patients were satisfied with the function and 96.7% of the patients were satisfied with the sensibility. In conclusion oral tactile sensibility and maximal occlusal force of implants have changed with the postinsertion time. Oral tactile function of implants was lower than that of the natural teeth, but for the maximal occlusal force there was no difference between implants and natural teeth.

• The Journal of the Korean dental association
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• v.58 no.1
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• pp.45-49
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• 2019

Korean society is experiencing a very rapid change in population aging. Oral diseases, including dental caries and periodontal disease, are usually cumulative and make oral health worse with age. Preventing tooth loss through the prevention and treatment of caries and periodontal diseases are essential for retaining oral function later in life. This study aimed to identify the trend in oral health status among elderlies over 65 years old, using major oral health indicators of Health Plan 2020. The fifth, sixth, and seventh Korea National Health and Nutrition Examination Survey (KNHANES V, VI, VII) were used in the present study to estimate the number of remaining natural teeth, the rate of 20 or more natural teeth, the rate of chewing difficulty, and the rate of oral health check-up of elderly. The number of remaining natural teeth increased from 15.6 in 2010 to 17.1 in 2015, and the rate of 20 or more natural teeth also increased from 45.8% in 2010 to 53.7% in 2015. The rate of chewing difficulty was similar but declined a little from 44.3% in 2010 to 42.9% in 2017. Finally, the rate of oral health check-ups of the elderly increased significantly from 12.2% in 2010 to 21.1% in 2017.

• Journal of Dental Rehabilitation and Applied Science
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• v.20 no.1
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• pp.1-8
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• 2004

STATEMENT OF PROBLEM: Tensile strength of metal crown cemented with provisional cement have shown clinically difference between metal abutment of implant and natural abutment. PURPOSE: This study was tested to compare the tensile strength of provisional cement on the natural abutment and metal abutment. MATERIAL AND METHODS: Out of the 20 premolars that were selected for this experiment, each 10 were prepared of abutments by chamfer and rounded shoulder margin and then duplicated to produce 20 metal abutments that were same to natural teeth. Then, crowns were fabricated to fit the total 40 natural & metal abutments to be cemented by cavitec, to be added of regular, repetitive vertical load, and to be measured of tensile strength by using Universal Test Machine. RESULTS: There was statistically significant difference in the tensile strength between the crowns cemented to the natural & metal abutments, but no statistically significant difference was observed between the chamfer and the shoulder gingival margin of the each abutments. CONCLUSIONS: Tensile strength of metal teeth is greater about 2 more times than that of natural teeth when it is cemented with Cavitec.