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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Restorative Dentistry and Endodontics
Journal Basic Information
Journal DOI :
The Korean Academy of Conservative Dentistry
Editor in Chief :
Volume & Issues
Volume 5, Issue 1 - Dec 1979
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AN EXPERIMENTAL STUDY ON THE PENETRATION OF RESTORATIVE RESINS INTO ACID-ETCHED HUMAN ENAMEL
Lee, Seung-Jong ;
Restorative Dentistry and Endodontics, volume 5, issue 1, 1979, Pages 7~12
After applying three types of composite resins - Hi-Pol composite with Enamel bond, Hi-Pol composite without Enamel bond, Restodent - to the intact and the ground surface of tooth that had been acid etched for one or two minutes, the author observed the penetration of these resins into the acid etched enamel surface with scanning electron microscope. The results were as follows. 1. All the experimented materials showed the penetration into the acid etched enamel surface, and the average depth of penetration was 7 microns. 2. There was no significant difference in the penetration of these three resins despite different etching, time. 3. The grinding of the Enamel surface before acid - etching was not effective in altering the depth of penetration of these materials.
AN EXPERIMFNENTAL STUDY ON THE SURFACE ROUGHNESS OF ACID ETCHING ENAMEL SURFACE IN HUMAN TEETH
Lee, Eun-Goo ;
Restorative Dentistry and Endodontics, volume 5, issue 1, 1979, Pages 13~18
The purpose of this study was to measure the roughness on the acid -etching surface. The etching agents of three-kinds composite resins were used to etch the tooth surface. Newly extracted I5-anterior teeth were invested with self-curing acrylic resin, and the labial surface was exposed. The exposed labial side was polished with abrasive papers and finally polished on polishing machine with zinc oxide powder. After the teeth were polished, the specimens were washed by water and dried by air. Surface roughness tester, Taylor-Habson's Taly Surf-10, (Fig-1) was used to measure roughness of this unetched tooth surface. And that, the specimens were divided into three groups. The first group was etched with Restodent etchant, the second group was etched with Nuva-system etchant, and Hi-pol etching agent was used in the third group. And the surface roughness tester was used to measure roughness of the etching teeth surface. The results obtained were as follows. 1. The roughness of acid-etched enamel were increased
. 2. Hi-pol etchant produced the smoothest surface(
). 3. Restodent etchant(
) and Nuva-system etchant(
) produced rougher surface than Hi-pol.
AN EXPERIMENTAL STUDY ON THE BONDING STRENGTH OF COMPOSITE RESINS TO ETCHED ENAMEL SURFACE WITH PHOSPHORIC ACID
Park, Kyung-Jung ;
Restorative Dentistry and Endodontics, volume 5, issue 1, 1979, Pages 19~23
This experimental study was made to investigate the tensile strength of composite resins to etched enamel surface with a 50% phosphoric acid. Recently extraced 40 maxillary incisors were chosen. These were divied into 4 groups: Group I: Restodent adaptation to the etched enamel surface with 50% phosphoric acid. Group II: Restodent adaptation to only the ground enamel surface. Group III: Hi-pol adaptation to the etched enamel surface with 50% phosphoric acid. Group IV: Hi-pol adaptation to only the ground enamel surface. The results were as follows: 1. The tensile strength of Hi-pol showed much better results than that of Restodent. 2. Hi-pol and Restodent on the ground enamel surfaces showed little difference. 3. Adhesion to enamel increased on the average over 200% after a 50% phosphoric acid etch.
EXPERIMENTAL STUDY ON THE ANTIBACTERIAL EFFICACY OF A FEW FILLING MATERIALS
Kim, Yung-Hai ;
Restorative Dentistry and Endodontics, volume 5, issue 1, 1979, Pages 25~28
The antibacterial efficacy of a few filling materials were studied in vitro. Zinc oxide eugenol cement. dycal, cavitec, hipol, cervident, clearfill and microfill were tested against Staphylococcus albus and Lactobacillus acidophilus on thioglycolate agar in order to determine whether the materials are effective inhibitors of bacterial growth. 1. Of these materials tested, zinc oxide eugenol cement was the most effective inhibitor of bacterial growth and revealed about 5.5mm in width of inhibition zone against Staphylococus albus and about 5.0mm against Lactobcillus acidophilus. 2. Dycal was moderate inhibitor of the both bact
ria showing 2.5mm of the zone in width. 3. Cavitec was the slightest effect against the both bacteria 4. Composite resins tested in this study showed no evidence of inhibiting bacterial growth against the both bacteria.
AN EXPERIMENTAL STUDY ON COEFFICIENT OF THERMAL EXPANSION OF DENTAL INVESTMENTS
Lee, Myung-Jong ;
Restorative Dentistry and Endodontics, volume 5, issue 1, 1979, Pages 29~34
The purpose of this study was to measure thermal expansions of dental investments, Biovest(Casting Investment. Dentsply International INC, U.S.A.), Multi-Best (Use for all dental chrome-cobalt alloys, The Ransom & Randolph Co. U.S.A.), Kerr(Inlay Investment. Sybron Kerr, U.S.A.), O. K. (Inlay Investment. Shofu Dental MFG, Co. Japan), Whip-Mix (Cristobalite Inlay Investment. Whip-Mix Corporation. U.S.A.). Thermal expansion of specimens(5mm in diameter and 50mm in length) was measured by a dilatometer at the temperature range from
by comparing expansion between standardized quartz and experimental specimens with heating rate about
/hr. The following results were obtained. 1. The coefficient of thermal expansion of Biovest was
in the water powder ratio 18/100 and
in the water powder ratio 28/100. Those of Multi-Best were
in the water powder ratio 14/100 and
in the water powder ratio 24/100. 2. The coefficient of thermal expansion of Kerr were
in the water powder ratio 38/100 and
in the water powder ratio 48/100. Those of O. K. were
in the water powder ratio 33/100 and
in the water powder ratio 43/100 3. The coefficient of thermal expansion of Whip-Mix were
in the water powder ritio 40/100 and
Fein the water powder ratio 50/100. Those of Hi-Heat were
in the water powder ratio 28/100 and
in the water powder ratio 38/100.
RADIOGRAPHIC STUDY OF THE POSITION OF APICAL FORAMEN IN ENDODONTIC THERAPY.
Lim, Sung-Sam ;
Restorative Dentistry and Endodontics, volume 5, issue 1, 1979, Pages 35~40
The author observed thy actual position of apical foramen and the radiographic appearance of files when the files were filled through canals to the external surface of apical foramen in 280 canals of extracted teeth. All the teeth were radiographed by bisecting technic and once again Walton's projection was employed on mandibular molars. The results were as followings. 1. Sixty five percents of 280 canals were actually classed as having foramina deviant from true apex of root. 2. 160 of 280 canals(Fifty seven percents) appeared to be filled short of apex on the radiograph. 3. When Walton's projection was employed to open up two mesial canals of mandibular molars and compared to straight-on projection, twelve of 120 canals Ten percent appeared to be different in radiographic appearence.
A STUDY OF COMPRESSIVE STRENGTH OF PIN SUPPORTED RESTORATIONS
Lee, Han-Ryong ; Lee, Chung-Suck ; Choi, Sung-Keun ;
Restorative Dentistry and Endodontics, volume 5, issue 1, 1979, Pages 41~46
Silver amalgam has superior mechanical and physical properties, therefore it has been widely used in dental clinics. But we have found the silver amalgam failures frequently, its important reasons are fracture, fallen-out, tarnish, corosion and secondary caries etc. The author studied the compressive strength of silver amalgam. The author made the standardized specimen, prepared the Black's Class II cavity on chromecobalt alloy, and placed the three types of Unitek
pin (Type of pins are straight type, "ㄱ" bent type, "
" bent type pin. The compressive strength was measured by (Dynamic Strain Meter Shinko Co. Japan). The author took the following results by comparing with the control group, not used pin. 1) Compressive force of silver amalgam in straight type pin was
in "ㄱ" type bent pin,
" type bent pin,
in the control group. 2) The statistic significance of the compressive strnegth between each group showed that "ㄱ" type, bent pin is stronger than the control group or straight type pin. 3) There were no difference of significances between the control group and straight type pin, control group and "ㄱ" type bent pin and "
" type bent pin, "ㄱ" type' bent pin "
" and type bent pin.
A STUDAY ON THE ROOT CANAL MORPHOLOGY OF HUMAN MANDIBULAR SECOND MOLAR WITH TRANSPARENT SPECIMENS
Lee, Chung-Sik ;
Restorative Dentistry and Endodontics, volume 5, issue 1, 1979, Pages 47~51
Fifty two human mandibular second molars were chosen to study the anatomy of the root canal. The experimental teeth were injected with china ink, decalcified, cleared and used in study, in vitro, to determine the number of root, the number of root canals, canals per root, frequency and location of transverse anastomoses, frequency and location of lateral canals and frequency of the apical deltas. The results were as follows; 1. Most of the teeth showed three canals, but 19.2% of the teeth were found to have two canals and 9.6% of them four canals. 2. In so far as observing two canals per root, 80.8% of the teeth were found to have two canals in mesial root and 9.6% of them in distal canal. 3. In roots with, two canals, the seperated apical foramen appeared in 59.5% in mesial side and 40.0% in distal side, and the common apical foramen appeared in 40.5% in mesial side and 60.0% in distal side. 4. Of the two root canals in one root, 36.2% of the canals were found to have transverse anastomoses and were usually located in the apical third of the root. 5. 23.1% of 52 teeth were found to have lateral canals, and ramifications were mainly located in the apical third of the root.