중간지대치가 포함된 고정가공의치의 지대치 주위조직에서 발생하는 응력에 관한 광탄성학적 연구

조광헌,최부병,박남수,Jo, Kwang-Hyun,Choi, Boo-Byung,Park, Nam-Soo 대한치과보철학회 1987 대한치과보철학회지 Vol.25 No.1

The purpose of this study was to evaluate the stress distributions of the fixed partial denture with five unit intermediate abutment. This fixed partial denture was attached to a three dimensional photoelastic epoxy resin model. Three dimensional photoelastic models were used, with the stress areas recorded photographically. A vertical load was applied to the second molar, which is the most posterior abutment of the fixed partial denture. Similarly, a vertical load was applied to the first molar because this tooth receives the heaviest masticatory load. These loads were added to two types of fixed partial denture. the rigid connector, and the nonrigid connector which was connected on the distal side of the intermediate abutment by a key and keyway device. After the stress patterns in surrounding tissues were observed, the following conclusions were as follows: 1. When the vertical load was applied to the first and second molars on the occlusal surfaces, the surrounding tissues of the roots of the canine, the second premolar, and the second molar were all compressive stresses. 2. When the vertical load was applied on the occlusal surface of the second molar, the tissue surrounding the roots of the canine, the second premolar, and the second molar all showed more stresses with the nonrigid connector than with the rigid connector. 3. When the vertical load was applied to the occlusal surface of the first molar, the stress concentration on the canine and the second molar was similar, whether the rigid or nonrigic connectors were used. However, on the second premolar, the stress concentration shown by the nonrigid connector was noticeably more than that shown by the rigid connector. 4. Whether the rigid or nonrigid connectors were used, when the load was placed on the first molar, the stress concentration on the canine and the second premolar was greater than that observed for the second molar. When the load was placed on the second molar, the load affected the second molar more than the canine and the second premolar.

齒科材料用 금-은-팔라듐合金의 硬化特性

曺光憲,李基大 慶北大學校 1983 論文集 Vol.36 No.-

It has been known that noble metal alloys are one of the most important materials for dental use. In particular, silver base alloys containing copper are most widely used because of their age-hardenability. But their ageing process has not been fully understood. In the present work, the electrical resistivity and hardness change during ageing of dental silver alloys were measured and the ageing process was discussed. Principal results were as follows; (1) The standard compositions of the silver alloys were (50-55wt%) Ag+(28-20wt%) Pd+(10wt%)Cu+(5-12wt%)Au (2) The ageing treatment at 350 to 450℃ for 10 to 60 min should be the optimum condition for age-hardening treatment of these alloys. (3) The electrical resistivity showed a characteristic peak in the early stage of isochronal ageing. This peak will probably correspond to clustering of certain solute atom. (4) The isothermal ageing curves of A, B alloys were like each other in shape. The apparent activation energy for the precipitation process were calculated to be about 39 and 36Kcal/mol, respectively.

농어촌 및 소도시에 있어서의 환자진료의 문제점

조광헌 대한치과의사협회 1984 대한치과의사협회지 Vol.22 No.9

咬合의 安定性과 咬合音에 關한 硏究

曺光憲,尹昌根 慶北大學校 齒科大學 1984 慶北齒大論文集 Vol.1 No.1

The purpose of this study was to investigate about the relationship between the tapping sound and occlusal contacts in centric occlusion and apply its results to clinical parameter as a diagnostic aid. Forty-seven subjects, 20 to 25 years of age, without symptoms of stomatognathic dysfunction were selected from dental students in Chosun University for this study. The tapping sound in centric occlusion were recorded as bone conduction sounds using a gnathosonic instrument (Dental Sound Checker TME-202C,Yoshida Co.,Japan) and the average duration of the right and left sound was measured. With these records, the subjects were classified in three groups as Class I (with stable contacts), ClassⅡ (with mixed contacts) and Class Ⅲ (with unstable contacts). Occlusal stability was evaluated by the nature of centric occlusal contacts. The centric occlusal contacts were marked and surveyed on the upper and lower occlusal surfaces of the stone models which were mounted on Hanau model H articulator by the interocclusal records using rubber base impression material. Finally, the relationship between the occlusal pattern and nature of centric occlusal contacts was observed. The results of this study were as follows: 1. In the 47 subjects, 16 were Class Ⅰ,15 were Class Ⅱ and 16 were Class Ⅲ ,and their average durations were 8.50 msec., 9.77 msec. and 13.68 msec. respectively. 2. The average numbers of teeth with both mesiodistal and buccolingual coupled contact were 5.64 and those of occlusal contact points in C.O. were 57.81. The ratio of the surface contact over 1mm in diameter to the total contact point was 44.54% in Class I group. 3. The average numbers of teeth with coupled contact were 5.53 and those of contact points were 57.33. The ratio of the surface contact over 1mm in diameter to the total contact point was 52.67% in Class Ⅱ group. 4. The average numbers of teeth with coupled contact were 3.75 and those of contact point were 47.63. The ratio of the contact points over 1mm in diameter to the total contact points was 54.33% in Class Ⅲ group.

咬合의 安定性과 咬合音에 關한 硏究

曺光憲 朝鮮大學校 口腔生物學硏究所 1984 口腔生物學硏究 Vol.7 No.-

타액 및 혈액 오염이 상아질접착에 미치는 영향

조광헌,안식환,박진훈,김기옥,김성교 大韓齒科保存學會 1996 Restorative Dentistry & Endodontics Vol.21 No.2

齒科用 非貴金屬合金의 物理的 性質에 미치는 鑄型溫度의 影響

曺光憲,盧正剋,李基大 대한치과기재학회 1985 대한치과재료학회지 Vol.12 No.1

齒科用 非貴金屬合金으로 널리 使用되고 있는 니켈-크롬系 合金인 Ticonium Premium 100 과 코발트-크롬系 合金인 Regalloy 를 對象으로 500, 600, 700, 800, 900 및 1,0000℃의 鑄型溫度로 變化시켜 遠心鑄造한 後, 硬度 및 引張强度를 測定하고 微細組織과 引張試片 破齒面을 觀察하여 아래의 結果를 얻었다. 니켈-크롬系 合金인 Ticonium Premium 100 은 鑄型溫度가 上昇할수록 結晶粒 이 粗大하게 變化함에 따라 硬度 및 引張强度도 多少의 減少를 나타내었다. 코발트-크롬계 合金인 Regalloy 는 鑄型溫度가 上昇할수록 結晶粒이 粗大하게 變化함에 따라 硬度 및 引張强度의 顯著한 減少를 나타내었다. 코발트-크롬계인 Regalloy 는 니켈-크롬系 合金인 Ticonium Premium 100 비해 硬度 및 引張强度가 높게 나타났다. 引張試片 破齒面은 두 合金 모두에서 鑄型溫度가 上昇할수록 微細氣孔이 破齒面의 中心部에 集中되는 傾向이 增加하였으며 延性破斷에서 脆性破斷으로 轉移되는 樣相을 觀察할 수 있었다. 良質의 鑄造組織을 얻고 鑄造本의 適合性을 向上시키기 위해서는 適切한 材料에 따른 適切한 鑄型溫度의 選擇이 要求된다. The purpose of this study was to investigate the effect of model temperature on the change in microstructure and physical properties of Ticonium Premium 100(Ni-Cr-alloy) and Regalloy(Go-Cr alloy). Tensile and hardness specimens were casted from the two types of alloys by centrifugal casting machine in mold temperatures of 500, 600, 700, 800, 900, and 1,000℃. After testing the hardness and the tensile strength of castings, the microstructure and the pattern of fracture were investigated and correlated with the above two mechanical properties. The results were as follows: As the grain size of Ticonium Premium 100 increased with the increase of mold temperature, the hardness and the tensile strength reduced slightly with the increase of grain size. As the grain size of Regalloy increased with the increase of mold temperature, the hardness and the tensile strength reduced remarkably with the increase of grain size. The values of the hardness and the tensile strength obtained from Ticonium Premium 100 were lower than those from Regalloy. As the mold temperature increased, the fractured surfaces of tensile specimens in the two types of alloys showed the tendency to form large voids in the center of specimens. Thus the ductile fracture was changed into the brittle fracture with the increase of mold temperature. There was the needs for the users to select the proper alloys and to control the mold temperature accurately in order to obtain the good and suitable castings.

數種 Ear face-bow의 正確性

손지영,曺光憲 慶北大學校 齒科大學 1985 慶北齒大論文集 Vol.2 No.1

The purpose of this study was to compare the accuracy of three different types of earface-bows with a true hinge axis and with five conventional arbitrary axis methods. Fifty subjects, 21 to 29 years of age, with clinically normal temporomandibular joint were selected from dental students and dental hygienic students for this study. And all of the subjects were trained to terminal hige axis and hinge movement. A 3㎝ square piece of millimeter graph paper was attatched to the skin in the region anterior to the tragus of the ear. Since the integument in the area was readily movable and influenced by the position of the head rest, all subjects were positioned erect in the chair with no head rest support while true hinge axis point and eight arbitrary axis points were marked on graph paper. The results of this study have been summarized as follows: Ninty-five percent of the method using the Twirl-Bow were within 5mm of the points of the kinematic axis, and the mean distance rrom the kinematic axis was 2.71±1.49mm. Eighty-two percent of the method using Quick Mount Face-Bow were within 5mm of the points of the kinematic axis, and the mean distance from the kinematic axis was 3.29±1.76mm. Eight hty-one percent of the method using the Slidematic Facebow were within 5mm of the points of the kinematic axis, and the mean distance from the kinematic axis was 3.30±2.22mm. Eighty-eight percent of Bergstrom's points were within 5mm of the points of the kinematic axis, and the mean distance from the kinematic axis was 3.15±1.43mm. Eighty-seven percent of Gisi's points were within 5mm of the points of the kinematic axis, and the mean distance from the kinematic axis was 3.23±1.54mm. Eighty-two percent of Beyron's points were within 5mm of the points of the kinematic axis, and the mean distance from the kinematic axis was 3.72±1.68mm. Fifty-one percent of Simpson's points were within 5mm of the points of the kinematic axis, and the mean distance from the kinematic axis was 5.01±2.02mm. Forty-two percent of Teteruck and Lundeen's points were within 5mm of the points of the kinematic axi is and the mean distance from the kinematic axis was 5.37±1.74mm. The acceptable degree of accuracy in hinge axis location by kinematic means is 1mm but in all methods of this study, less than 15 percent of the selected arbitrary point were within a 1mm radius from the terminal hinge axis point.

위상이동 형상측정법을 이용한 의치 중합 방법에 따른 적합도 검사

이청희,조광헌,최부병,Lee, Cheong-Hee,Jo, Kwang-Hun,Choi, Boo-Byung 대한치과보철학회 1999 대한치과보철학회지 Vol.37 No.4

According to repeated measurements and correction procedures, the accuracy of the phase-shifting profilometry was developed. At first, after 20 final models for maxillary complete denture were duplicated , the mucosa sur-faces of models were measured with the phase-shifting proflometry and each mirror view of these was calibrated. Maxillary casts were divided into 4 groups of 5 casts per each, and wax dentures with 2 sheets of baseplate wax and artificial teeth were made and then cured according to the curing method of each group. Group I ; quick curing with QC-20 acrylic resin Group II ; 9 hour curing with QC-20 acrylic resin Group III ; SR-Ivocap system Group IV ; metal base and quick curing with QC-20 acrylic resin. After curing, polishing, and storing at $37^{\circ}C$ in saline for 30 days, the forms of the impression surface of the dentures were measured with the phase-shifting profilometry. Then, the impression surface form of each denture was placed in the optimal position of com-parison with the mirror view of the same final cast. The amount and direction of distortion of each denture was analyzed and the effects of polishing and storage in each denture were compared, The obtained results were as follows : 1. In Group I, the denture was observed as the appearance distorted in the opposite direction of the mucosa and the postero-lateral part of palatal portion of the denture was observed as the appearance separated from the mucosa. Also, the buccal flanges of the denture were observed as the appearance distorted in the direction of the mucosa. 2. In Group II, the postero-lateral part of palatal portion of the denture was observed as the appearance separated slightly from the mucosa. The bilateral buccal flanges of denture were observed as the appearance distorted severely in the direction of the mucosa. 3. In Group III the bilateral part of the residual ridge crest portions and the buccal flanges of the denture were observed as the appearance distorted in the direction of the mucosa, and specially, the buccal flanges of the maxillary tuberosities were distorted severely. 4. In Group IV, the acrylic resin base of the buccal portion of the denture was observed as the appearance distorted in the opposite direction of the mucosa. 5. The phase-shifting profilometry, done with repeated measurements and correction procedures, was effective in comparing the amount and direction of distortion at every position after the laboratory work and the delivery of maxillary complete denture.

근관치료를 받은 소구치에서의 post 및 core수복 후 잔존치질량이 파절저항에 미치는 영향

김양교,조광헌 慶北大學校 齒科大學 1991 慶北齒大論文集 Vol.8 No.2

The purpose of this was to evaluate the ferrule effect of endodontically treated permolars as affected by various amounts of tooth structure. Forty recently extracted, intact premolars were used. The teeth were divided into four groups of ten each. In Group I, the coronal portions of the teeth were removed at the cemento-enamel junction. In Group Ⅱ, the coronal portions of the teeth were removed to 1mm above the cemento-enamel junction. In Group Ⅲ, the coronal portions of the teeth were removed to 2mm above the cemento-enamel junction. In Group Ⅳ, the coronal portions of the teeth were removed to 3mm above the cemento-enamel junction. Every tooth was endodontically treated and a prefabricated paralleled Para-post was inserted in each canal and a composite resin core was built to 7mm above the cemento-enamel Junction. Thereafter, a complete cast crown was made from nickel-chrome alloy and cemented with zinc phophate cement to each tooth. The failure loads of the specimens were measured by an Instron Universal testing machine. The mean values of failure loads for the four groups were statistically compared by studen't t-test. The results were as follows: 1. There was a statistically significant difference between the failure loads of Group I (removed at the cemento-enamel junction) and the others(p<0.05). 2. The mean values of the failure loads of the Group Ⅱ (removed to 1mm above the cementoenamel junction), Group Ⅲ (removed to 2mm above the cemento-enamel junction) and Group Ⅳ(removed to 3㎜ above the cemento-enamel junction) exhibited values the same order as Group Ⅳ (removed to 3mm above the cemento-enamel junction), Group Ⅱ (removed to 1mm above the cemento-enamel junction), Group Ⅲ (removed to 2mm above the cemento-enamel junction) but there was no statistically significant difference among them(p>0.05).