• The Journal of Korean Academy of Prosthodontics
• /
• v.44 no.2
• /
• pp.157-164
• /
• 2006

Purpose: The purpose of this study was to compare the fracture strength of the zirconia monolithic all-ceramic crowns according to the thickness(0.5 mm, 0.8 mm, 1.1 mm) and IPS Empress II ceramic crown of 1.5 mm thickness. Material and method: Eight crowns for each of 3 zirconia crown groups were fabricated using CAD/CAM system(Kavo, Germany) and eight Empress II crowns were made from silicone mold and wax pattern. Each crown group was finished in accordance with the specific manufacturer s instruction. All crowns were luted to the metal dies using resin cement and mounted on the testing jig in a universal testing machine. The load was directed at the center of crown with perpendicular to the long axis of each specimen until catastrophic failure occurred. Analysis of variance and Tukey multiple comparison test(p<.05) were applied to the data. Results and Conclusion: 1. The fracture strength of the zirconia monolithic all-ceramic crown was higher thickness increased(p<.05). 2 The fracture strength of 1.1 mm thickness zirconia monolithic all-ceramic crown was higher than the fracture strength of 1.5 mm thickness IPS Empress II crown(p<.05). 3. The fracture strength of 0.5 mm thickness zirconia monolithic all-ceramic crown exceeded maximum occlusal forces.

• Restorative Dentistry and Endodontics
• /
• v.28 no.5
• /
• pp.409-418
• /
• 2003

본 연구는 치수 염증 시 IL-8과 MCP-1 분비에서 neuropeptide의 역할에 대해 관찰하고자 발거된 건전한 치아를 수직 파절시켜 치수조직을 채취하여 배양된 치수세포 및 혈관내피세포(ECV 304세포)를 각기 다른 농도의 Substance P(SP)로 12시간 자극하였고, 24시간 동안 4시간 간격으로 시간대별로 자극하였으며, 또 치수세포를 Calcitonin gene-related peptide (CGRP)로 12시간 자극하였다. 이들 세포를 SP길항제 (Spantide)로 15분간 차단한 후 SP로 12시간 재 자극하였으며, SP와 CGRP혼합액을 12시간 자극하였다. 상기의 실험 후 부유물로 ELISA를 시행하여 IL-8과 MCP-1의 분비 량을 측정하였다. 치수세포는 SP로 자극 시 IL-8이 현저히 증가한 반면, CGRP는 효과가 없었으며, SP와 CGRP를 혼합자극 시 시너지 효과 또한 없었고, Spantide는 치수세포의 IL-8과 MCP-1의 분비를 차단시켰다. 치수세포를 SP로 24시간 동안 4시간 간격으로 자극 시 8시간 후 최대의 IL-8은 분비량 나타내었으며, 8시간과 12시간 사이에서 최대의 MCP-1 분비량을 나타내었다. ECV 304세포를 SP로 자극 시 IL-8과 MCP-1 분비량이 미약하게 증가하였으며, Spantide는 ECV 304세포의 IL-8과 MCP-1 분비를 억제시켰다.

• Restorative Dentistry and Endodontics
• /
• v.35 no.2
• /
• pp.65-68
• /
• 2010

Due to the improvement of the composite resin and esthetic desire of the patient, amalgam restoration has been replaced by composite resin. However, still there are many unsolved problems, for example, technique sensitivity, polymerization shrinkage stress and limited mechanical properties. These factors results in fracture of the restoration and secondary caries of the tooth. Also the use of the dental bonding system should be used for the retention of the restoration. In this paper, I want to talk about the present and the future of the remineralizing component released from dental composite resin to overcome the secondary caries and there possibility in the clinical use.

• Journal of the Korean Academy of Esthetic Dentistry
• /
• v.29 no.1
• /
• pp.54-61
• /
• 2020

Forced orthodontic eruption(FOE) is a non-surgical treatment approach that allows augmenting both soft- and hard-tissue profiles of potential implant sites, by forced orthodontic extrusion of "hopeless" teeth and their periodontal apparatus. By stretching the gingival and periodontal ligament fibers during extrusion, tension is imparted to the entire alveolar socket, stimulating osseous apposition at the alveolar crest. FOE increases the width of the attached gingiva, and the mucogingival junction remains stable when the gingival margin migrates coronally. Based on these effects, FOE of non-restorable teeth prior to implant placement is a viable alternative to conventional surgical augmentative procedures in implant site development. The aim of this case report is to describes coronal soft-tissue augmentation around fractured teeth, which was achieved by FOE before implant placement.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.37 no.1
• /
• pp.39-47
• /
• 2021

Compared to conventional method, if metal framework of removable partial denture is fabricated by selective laser melting, various laboratory works are omitted, saving time and simplifying the process. In addition, metal framework with homogeneous density can be obtained, expecting excellent mechanical properties, especially resistance to fatigue fracture. In these cases, impression were taken using conventional methods in partial edentulous patients, master casts were fabricated and scanned to obtain digital data. After designing the metal frameworks on the scanned data, removable partial dentures were fabricated using selective laser melting methods. Through these procedure, satisfactory outcomes were achieved both in functional and esthetic aspects.

• Korean Journal of Cleft Lip And Palate
• /
• v.20 no.1
• /
• pp.49-58
• /
• 2017

We report the rehabilitation of Class II malocclusion with multiple teeth fracture due to trauma. A multidisciplinary team approach was necessary to treat patient's problems such as bone fracture, malocclusion, and multiple teeth fracture. Emergency conservative treatment, orthodontic treatment and prosthetic restoration successfully restored the occlusion. However, special considerations were needed along the orthodontic treatment process due to the unexpected complications such as ankylosis, root resorption and detection of additional teeth fractures.

• Journal of dental hygiene science
• /
• v.4 no.1
• /
• pp.21-25
• /
• 2004

In modern times, children's trauma is increasing every year because of car accidents and life environment changes. There is a limit to prevent traumatic damage for oral cavity organization. The fundamental data of trauma treatment and prevention will be presented through the survey and analysis of traumatic teeth damage. I examined 113 patients from Oct. 4th, 2000 to Feb. 27th, 2004 at Dept. of Children's Dental Clinic, Kangnung National University. The results are as follows. (1) The trauma frequency of male subjects is higher than that of female at a rate of 2.05:1. The average age is 5.27 for men and 5.27 for women. The highest percentage of trauma patients is among 2 year old children. It is 21.2%. (2) A patient survey was taken at a trauma treatment hospital. On the first day 34.4% of the patients had come to receive treatment of their first set of teeth. However, after a week, 38.8% of the patients had received treatment on their permanent teeth. (3) As a result of falling, 59% of patients needing treatment on their first set of teeth. 55.1% of patients is permanent teeth. As a result of bump against physical solid, 26.6% of patients is the first set of teeth and 26.5% of patients is permanent teeth. (4) Teeth damage happened at home. 42.1% were male. 35.1% were female. According to trauma, 59.4% of teeth damage happened at home. 28.6% of permanent teeth damage happened at school or kindergarten. (5) According to trauma, the number of teeth damaged was in the first set of teeth are as follows: 56.3%, one-31.3%, three or four-6.3% each. For permanent teeth: two-46.9%, one-28.6%, four over-16.3% and three-8.2%. Over four teeth is larger number for permanent teeth. (6) 56% of first set of teeth patients and 43.4% of permanent teeth patients were male. 56.8% of first set of teeth patients and 43.2% of permanent teeth were female. Trauma happened to both male and female frequently in the first set of teeth. (7) Most of the tooth damage which was in the first set of teeth and permanent teeth was done to the upper jaw. 75% of patients are the first set of teeth. 63.8% of patients are permanent teeth. Trauma is very high in the two mid teeth of the upper jaw. (8) According to trauma survey, 30.2% is from impulse. 28.0% is from crown fracture, 14.7% is from depression. 8.9% is from concussion. 7.1% is from full dislocation of a joint. 2.2% of patients are extrusion. 1.8% is from displacement. According to teeth damage trauma, 35.8% is pulse in the first set of teeth. The breaking of the crown of a tooth happened a lot in permanent teeth. (9) According to data, 43.2% of teeth damage in the first set of teeth goes without treatment. In permanent teeth, it is 38.9%. After treatment, 22.0% of first set of teeth treatment requires a dental pulp treatment. In permanent teeth, which is used for temporary acid etching resin restoration.

• Journal of Technologic Dentistry
• /
• v.37 no.4
• /
• pp.243-250
• /
• 2015

Purpose: The aim of this study was to investigate the shear bond strength between various commercial zirconia coping and veneering ceramic, and to observe the failure mode. Methods: For each zirconia block (iJAM Emerald, LUXEN Smile block, ICE Zirkon transluzent), 10 rectangular specimens were layered with Cercon ceram kiss, IPS e.max ceram, ICE Zirkon ceramic according to recommended by the manufacturer. The shear bond strength tests of the veneering porcelain to zirconia were carried out until fracture by a universal testing machine. After the shear bond tests, failure modes were characterized visually, under a stereomicroscope, such as adhesive, cohesive, or mixed. Data were analyzed with One-way ANOVA followed by Scheffe's tests. Results: The shear bond strength ($mean{\pm}SD$) of zirconia-veneer ceramic were JC group $13.9{\pm}3.6MPa$; JE group $17.7{\pm}2.4MPa$; JI group $15.1{\pm}2.5MPa$; LC group $9.5{\pm}1.5MPa$; LE group $16.2{\pm}2.3MPa$; LI group $12.6{\pm}0.8MPa$; ZC group $16.0{\pm}2.3MPa$; ZE group $18.5{\pm}3.4MPa$; and ZI group $15.3{\pm}3.2MPa$. The One-way ANOVA showed a significant difference between groups (p<0.05). The failure mode in most experimental groups was mixed failure, except for the LC group, which showed adhesive failure, and JE group, LE group and ZE group showed cohesive failure. Conclusion: For IPS e.max ceram, the shear bond strength value was highest for all kinds of zirconia blocks. For ICE Zirkon transluzent, the shear bond strength value was highest for all kinds of veneering ceramics. Most of experimental group interfaces revealed mixed failure mode.

• The Journal of Korean Academy of Prosthodontics
• /
• v.40 no.5
• /
• pp.441-450
• /
• 2002

The purpose of this study was compare the fracture strength of the IPS Empress ceramic crown according to the occlusal depth (1.5mm, 2.0mm, 2.5mm) and axial inclination ($4^{\circ},\;8^{\circ},\;12^{\circ}$) of the lower second premolar. After 10 metal dies were made for each group, the IPS Empress ceramic crowns were fabricated and cemented with resin cement. The cemented crowns were mounted on the testing jig with inclination of 30 degrees and the universal testing machine was used to measure the fracture strength. The results of this study were as follows : 1. The fracture strength of the ceramic crown with 2.5mm depth and $12^{\circ}$ inclination was the highest (1284 N). Crowns of 1.5mm depth and $8^{\circ}$ inclination had the lowest strength (951 N). 2. There were no significant differences in the fracture strength by axial inclination of the same occlusal depth group. 3. Most fracture lines began at the loading area and extended through proximal surface perpendicular to the margin, irrespective of occlusal depth.

• The Journal of Korean Academy of Prosthodontics
• /
• v.39 no.2
• /
• pp.220-229
• /
• 2001

This study was performed to evaluate the fracture resistance of three improved die stone materials according to water/powder ratio. There are lots of handling conditions which affect the physical properties of improved dental stone, and it's well known that the water/powder ratio significantly affect the strength of die stone. If water/power ratio was incorrect, following disadvantages were showed : (1) susceptibility to dimensional change due to abrasion, (2) limited reproduction of fine detail, (3) lack of strength. The maxillary master casts were made of additional silicone impressions(Exaflex, GC America. Inc. USA). Three type IV die stones such as Fuji Rock (GC Europe Intreleuvenlaan, Leuven, Belgium), Velmix(Kerr, Manufacturing company, USA), and Crytal Rock( Maruishi Gypsum Co. Ltd, Japan) were tested. A total of 160 casts were prepared, separated, and tested on the Instron Testing Machine(Model 4201, Co. USA). The obtained results of this study were as follows : 1. Fuji Reck and Velmix less 3ml than the water/power ratio of manufacturer's instruction showed the highest resistance to fracture. According to increasing water/powder ratio, fracture resistance was significantly increased(P<0.05). Crystal Rock showed the highest fracture value when it was mixed with the water/power ratio of manufacturer's instruction. 2. Water/powder ratio of the manufacturer's instructions and less 3ml than that showed lower fracture value of hand mix than that of vacuum mix. Water/powder ratio of more 3ml, 6ml than manufacturer's instructions was not significantly different between hand mix and vacuum mix(p>0.05). 3. Velmix had the highest viscoelastic value among three die materials when it was mixed with the manufacturer's instruction. Viscoelasticity was decreased according to increasing water/powder ratio.