• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.715-721
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• 2003

Dental injuries with crown fracture occur frequently, especially in young patient Reattachment of the crown fragment has been shown to yield good esthetic results in that original tooth anatomy is restored with a material that abrades at a rate indntical to that of the adjacent tooth substance and at the same time permits continual monitoring of pulpal status through the fragment. Case 1 was complicated crown fracture with pin-point bleed ing, that was treated by direct pulp capping with calcium hydroxide and fragment reattachment. Case 2 was in trusive luxation with complicated crown fracture and was treated by pulp treatment and fragment reattachment. Case 3 was uncomplicated crown fracture, and fracture line involved slightly biologic width and treated by reattachment of the crown fragment.

• Restorative Dentistry and Endodontics
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• v.37 no.4
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• pp.240-244
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• 2012

Crown reattachment is the most conservative treatment which can be used to restore fractured tooth, presumably with sufficient strength, while maintaining original contour, incisal translucency, and reducing chair time and cost. However, in case of crown fracture with pin-point pulp exposure, we should cautiously minimize the irritation to the pulp and consider pre-treatment pulpal status, choice of pulp capping materials, choice of bonding system and treatment sequence during crown reattachment procedures. This case reports the considerations while crown reattachment with direct pulp capping using calcium hydroxide (Dycal, Dentsply Caulk).

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.2
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• pp.201-209
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• 2021

In removable partial dentures, many types of retentive systems have been studied and applied in clinical treatment. One of those systems is the double crown denture system which is widely used in European countries such as Germany and Sweden. Telescopic double crown dentures have several advantages such as convenience in maintaining oral hygiene, enabling to transfer occlusal force along the long axis of the abutment, and secondary splinting effect between the abutments which leads to higher clinical performance compared to conventional removal partial dentures. In this clinical case, the patient was initially restored with a maxillary hybrid telescopic double crown denture with friction pin using remaining natural teeth as abutments. After 7 years, due to lack of recall check-up and poor oral hygiene, the abutment teeth were affected by periodontitis and 4 out of 5 of the abutment teeth had to be extracted. 3 additional implants were placed and the original abutment tooth with the inner crown was maintained. The mandible had fixed prostheses including implants but nevertheless, with strategic implant placement, the patient adapted well and was satisfied with the new maxillary tooth-implant combined double crown denture.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.3
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• pp.215-221
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• 2015

Treating patients with severely worn dentition often requires comprehensive prosthetic treatments. Oral rehabilitation and long-term stability could be achieved by analyzing the cause of the wear and changing vertical dimension. The temporary restoration procedure is executed and patient's adaptation is evaluated by long-term observation when treatment is accompanied with increasing vertical dimension. In this case, 54 year-old male presented with worn dentition and esthetic dissatisfaction. In oral manifestations, severely worn dentition with attrition and erosion is diagnosed. To evaluate change of vertical dimension, interocclusal rest space, facial appearance, pronunciation, clinical crown length, distance from incisor edge to labial vestibule are evaluated. Consequently, 2.5 mm increase of vertical dimension that based on articulator incisal pin is determined. After 8 weeks stabilization period with temporary prostheses, definitive prostheses are fabricated. After 6 months follow up period, satisfactory outcomes were achieved both in functional and esthetic aspects through this procedure.

• Journal of Technologic Dentistry
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• v.29 no.2
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• pp.151-161
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• 2007

To obtain the information of dental arch size and the distance from one tooth center to adjacent tooth center of occlusal surface of each tooth which is perforated by Pindex system on working cast for removable die system, 600 dental casts in Busan were examined. The distance of center of occlusal surface of each tooth and dental arch size were digitized. The results were as follows; 1. Mean values of the distance from center of maxillary central incisor to maxillary lateral incisor(tooth number 11$\sim$12, 21$\sim$22) is 5,7 mm, 12$\sim$13(22$\sim$23) is 5.9 mm, 13$\sim$14(23$\sim$24) is 6.9 mm, 14$\sim$15(24$\sim$25) is 7.1 mm, 15$\sim$16(25$\sim$26) is 8.4 mm, 16$\sim$17(26$\sim$27) is 10.2 mm, 11$\sim$21 is 7.30 mm. Mean values of the distance from center of mandibular central incisor to mandibular lateral incisor(tooth number 31$\sim$32, 41$\sim$42) is 4.5 mm, 32$\sim$33(42$\sim$43) is 4.8 mm, 33$\sim$34(43$\sim$44) is 6.3 mm, 34$\sim$35(44$\sim$45) is 7.2 mm, 35$\sim$36(45$\sim$46) is 9.2 mm, 36$\sim$37(46$\sim$47) is 10.7 mm, 31$\sim$41 is 4.7 mm. 2. Mean values of the distance from the center of maxillary right central incisor to the center of maxillary left central incisor(11$\sim$21) is 7.3 mm, 12$\sim$22 is 18.2 mm, 13$\sim$23 is 26.9 mm, 14$\sim$24 is 37.2 mm, 15$\sim$25 is 43.2 mm, 16$\sim$26 is 48.5 mm, 17$\sim$27 is 53.5 mm. Mean values of the distance from the center of mandibular right central incisor to the center of mandibular left central incisor(31$\sim$41) is 4.7 mm, 32$\sim$42 is 13.3 mm, 33$\sim$43 is 21.7 mm, 34$\sim$44 is 31.9 mm, 35$\sim$45 is 38.2 mm, 36$\sim$46 is 44.8 mm, 37$\sim$47 is 50.7 mm. 3. Mean values of the distance from the line of between 11$\sim$21 to 12$\sim$22 is 10.9 mm, 12$\sim$22 to 13$\sim$23 is 8.7 mm, 13$\sim$23 to 14$\sim$24 is 10.3 mm, 14$\sim$24 to 15$\sim$25 is 6.0 mm, 15$\sim$25 to 16$\sim$26 is 5.3 mm, 16$\sim$26 to 17$\sim$27 is 5.0 mm. 31$\sim$41 to 32$\sim$42 is 8.6 mm, 32$\sim$42 to 33$\sim$43 is 8.4 mm, 33$\sim$43 to 34$\sim$44 is 10.2 mm, 34$\sim$44 to 35$\sim$45 is 6.3 mm, 35$\sim$45 to 36$\sim$46 is 6.6 mm, 36$\sim$46 to 37$\sim$47 is 5.9 mm. 4. We checked the bottom side of cast to verify the position of dowel pin. There is no difference upper side and lower side.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.786-795
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• 2011

This paper described the characteristic of vibration in wind turbine system including gearbox housing, gear drive, blade, generator. Especially, in planetary gear set, planet gears are supported by flexible pin. So, in planet gear, to consider not only torsional movement but also lateral movement. And include housing movement, because wind turbine system is supported by mount. To find out the characteristic of vibration, take the excitation source and study campbell diagram in operating range. Results of campbell diagram, resonances are occurred at 81.2HZ, 104.7Hz by 2nd tooth passing frequency. And resonance are also occurred at 264.5HZ, 377Hz, 424.6Hz by 3th tooth passing frequency. From the result, take vibration reduced measures.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.537-543
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• 2003

This paper presents the improved procedure to assess static and dynamic strength of crawler type excavators. A fully integrated model including front attachment and chassis was prepared for structural analysis. In this paper, two types of loading input methods were investigated and the method imposing digging force directly on bucket tooth was more convenient than imposing cylinder reaction force on cylinder pin even if the two methods showed no discrepancy in analysis results. Static strength analysis was carried out for eight analysis scenarios based on two extreme digging positions, maximum digging reach position and maximum digging force positions. The results from static strength analysis were compared with measured stresses, cylinder pressures and digging forces and showed a good quantitative agreement with measured data. Dynamic strength analysis was carried out for simple reciprocation of boom cylinders. It was recognized that the effect of compressive stiffness of hydraulic oil was very important for dynamic structural behavior. The results from dynamic strength analysis including hydraulic oil stiffness were also compared with measured acceleration data and showed a qualitative agreement with measured data.

• The Journal of Advanced Prosthodontics
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• v.11 no.1
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• pp.7-15
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• 2019

PURPOSE. The aim of this study was to identify the effects of three aesthetic restorative materials on the wear between tooth and restoration by a pin-on-disk manner. MATERIALS AND METHODS. Six aesthetic restorative materials were used to prepare disk specimens for wear test, which were Lava Zirconia as zirconia group, Vintage MP and Cerabien ZR as veneering porcelain group, Gradia Direct microhybrid composite containing prepolymerized fillers, Filtek Z250 microhybrid composite containing zirconia glass and colloidal silica particles, and Filtek Z350 nanocomposite as composite resin group. Vertical loss of the worn cusp, change of the surface roughness of the restoration materials, and the surface topography were investigated after wear test under 9.8-N contact load. RESULTS. The porcelain groups (Vintage MP and Cerabien ZR) caused the largest vertical loss of teeth when compared with those of the composite resin and zirconia groups, and Filtek Z250 microhybrid composite results in the second-largest vertical loss of teeth. The surface of Filtek Z350 nanocomposite was deeply worn out, but visible wear on the surface of the zirconia and Gradia Direct microhybrid composite was not observed. When the zirconia surface was roughened by sand-blasting, vertical loss of teeth considerably increased when compared with that in the case of fine polished zirconia. CONCLUSION. It was identified that microhybrid composite resin containing a prepolymerized filler and zirconia with reduced surface roughness by polishing were the most desirable restorative materials among the tested materials to prevent the two-body wear between aesthetic restorative material and tooth.

• Journal of Technologic Dentistry
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• v.31 no.1
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• pp.63-74
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• 2009

Partial or complete prosthesis is needed when teeth are lost due to various kinds of reason. Artificial teeth recover occlusion instead of natural teeth. Artificial teeth are required of esthetics, fragile resistance and abrasive resistance. Artificial tooth is made of acrylic resin or porcelain. Nowadays, acrylic resin artificial teeth are mainly used. Acrylic resin teeth are occluded with natural teeth, gold alloy, Ni-Cr alloy or porcelain etc. Acrylic resin teeth have similar translucency, gloss of natural teeth. And it has good chemical bond with denture base material, but it has low wear resistance. The aim of this study is to compare wear resistance among several denture teeth(Endura, SR-orthosit-PE, Planustar) and between artificial resin denture teeth and opposing 3 restorative materials(gold, Ni-Cr alloy, porcelain). Wear tests were conducted with a rotating wear testing apparatus(pin-on-disk type wear tester) under conditions of rpm 180, 75 minutes and constant loading of 50N. The upper part was the cusp of maxillary first molar and the lower part was a disk type restorative materials. To make similar oral environment, water was supplied continually. The acrylic resin teeth wear was determined by weighing the cusp each 5 minutes during 75 minutes test. Vicker's hardness tester was used to evaluate the surface hardness of test specimens. The SEM was used to evaluate the wear surfaces. The results were as follows: 1. Wear rates of acrylic resin teeth opposing to the restorative materials were high in order of Porcelain, Gold, Ni-Cr alloy (p<.05). 2. Wear resistance rate opposing to the Porcelain disk, was shown in order of Endura, SR-orthosit-PE, Planustar. The wear rate of opposing to porcelain disk was above two times more than that of other groups (p<.05). 3. Wear resistance rates opposing to the Gold, Ni-Cr alloy disk, was shown in order of Endura, SR-orthosit-PE, Planustar (p<.05). 4. A degree of the surface hardness is directly proportional to the degree of wear resistance. There are statistically significant differences between each groups (p<.05).

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.278-290
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• 1997

The purposes of this study were to evaluate and compare the pulpal anesthesia induced by an inferior alveolar nerve block and that by Gow-Gates technique, and to investigate the relationship between pulpal anesthesia and intraoral soft tissue responses. After one side of mandibule was anesthetized with inferior alveolar nerve block or Gow-Gates technique using 2 % lidocaine with 1 : 100,000 epinephrine in 19 volunteers of ages between 24 and 29 (16 males and 3 females, average age 25.9 yrs.), electric pulp tests were done on the canine teeth of the anesthetized side and contralateral one before, at 1 min, continued at every 5 minutes until 60 min, and every 10 minutes until 100 min after completion of local anesthetic injection. Degree of pulpal anesthesia was classified as anesthetic failure, possible anesthesia and complete anesthesia by the criteria based on the thresholds to electric pulp test of contralateral canine and the currents of the electric pulp tester. Subjective signs on the lower lip and tongue were checked and prick-pin tests were done on the buccal gingiva of the first molar, buccal and lingual gingiva of the canine tooth at 5, 10 and 20 min after the completion of anesthetic injection. Thresholds to electric pulp test, degree of pulpal anesthesia and relationship between the pulpal anesthesia and soft tissue responses were analyzed with SPSS, paired t-test, Wilcoxon matched-pairs signed-ranks test and correlation analysis. The results were as follows : No significant differences were found in the peak thresholds to electric pulp test, in the induction time to it and in the depth of pulpal anesthesia between inferior alveolar nerve block and Gow-Gates technique (p>0.05). There was no significant relationship between pulpal anesthesia and soft tissue responses in both inferior nerve block and Gow-Gates technique.