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OBJECTIVE@#To evaluate the effects of different edge compensation angles on the fracture strength of multilayer zirconia all-ceramic crowns and traditional uniform zirconia all-ceramic crowns.@*METHODS@#The resin tooth preparation specimen of the mandibular first molar with a knife-edge was fabricated. A 3D digital model of the specimen was obtained by scanning it with a 3D dental model scanner. The 3D digital model was imported into computer aided design (CAD) software, and three 3D digital models of the full crown with the same surface shape are designed with the edge compensation angles of 30°, 45° and 60°, respectively. Then, the designed 3D digital model is imported into computer aided manufacturing (CAM) software. Three kinds of multilayer and homogeneous zirconia all-porcelain crowns with different edge compensation angles were fabricated, 10 each for a total of 60. The fracture load of each crown was measured under the electronic universal testing machine.@*RESULTS@#Fracture load of multilayer and uniform zirconia all-ceramic crowns, (4 322.86±610.07) N and (5 914.12±596.80) N in the 30° group, (5 264.82±883.76) N and (5 220.83±563.38) N in the 45° group and (4 900.42±345.41) N and (5 050.22±560.24) N in the 60° group, respectively. The fracture load of multi-layer zirconia all-ceramic crowns in the 30° group was significantly lower than that of homogeneous zirconia all-ceramic crowns(P < 0.05); there was no statistical significance in 45° group and 60° group(P>0.05). In the multi-layer zirconia all-ceramic crowns: the fracture load of the 30° group was significantly lower than that of the 45° group (P < 0.05); there was no significant difference between the 30° group and the 60° group, the 45° group and the 60° group (P>0.05).In uniform zirconia full crown group: the 30° group was higher than the 45° group, the 30° group was higher than the 60° group (P < 0.05), and there was no significant difference between the 45° group and the 60° group (P>0.05).@*CONCLUSION@#The fracture loads of three kinds of uniform and multilayer zirconia all ceramic crowns with different edge compensation angles can meet the clinical requirements. A smaller edge compensation angle is recommended when using traditional zirconia all-ceramic crowns, while 45° is recommended when using multi-layer zirconia all-ceramic crowns.
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Ceramics , Computer-Aided Design , Crowns , Dental Porcelain , Dental Prosthesis Design , Dental Restoration Failure , Dental Stress Analysis , Flexural Strength , Materials Testing , ZirconiumABSTRACT
Objective@#To evaluate the clinical efficacy of CAD/CAM glass-ceramic onlays in molars with complicated oblique crown fracture within 3.0 mm subgingival. @*Methods@#Fifty-six molars from 56 patients with complicated oblique crown fracture within 3.0 mm subgingival were recruited after endodontic treatment and divided into 2 groups according to the restorative methods used. The glass-ceramic onlays group was restored with CAD/CAM glass-ceramic onlays, while the all-ceramic crown group received CAD/CAM all-ceramic crowns. The success rates of the restorations were analyzed, and the sulcus bleeding index (SBI), plaque index (PLI), and gingival index (GI) were recorded at the prerestoration and postrestoration stages. @*Results @#After one year of follow-up, the success rate of the glass-ceramic onlay group was 96.4%, and the success rate of the all-ceramic crown group was 92.9%. The difference was not statistically significant (P > 0.05). No differences in SBI, PLI, or GI were found between the glass-ceramic onlay group and the all-ceramic crown group (P > 0.05).@*Conclusion@#Conclusion
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Objective@#To investigate the reliability of using virtual articulator in the fabrication of zirconia crowns for tetracycline discolored teeth.@*Methods@#To treat the patient with serious tetracycline stained teeth, we use zirconia crowns to shield the stained abutment teeth. To retain the characteristics of patient′s original occlusal contacts, meanwhile, to establish a stable and evenly distributed occlusal contacts, we recorded the functional movements of the patient′s jaw before preparing the teeth and transferred this relations to a physical articulator. Afterwards, relationship of the upper and lower arches was scanned through a specified fixature. Then we can customized the fabrication of the occlusal contacts of the restorations conveniently and efficiently with virtual articulator in CAD/CAM system.@*Results@#When the final restorations were inserted , a charming smile was achieved on patient′s face with satisfactory esthetics. With the application of virtual articulator in designing process, we made evenly distributed and stable bilateral occlusal contacting spots, smooth protrusive and lateral guidance on the lingual aspects of the upper anteriors. One year follow-up, this patient was observed in good oral hygiene, and was satisfied with her esthetic and functional outcome. The soft tissue around the restorations was assessed to be healthy and no signs of inflammation.@*Conclusion@# Applying the virtual articulator kits in CAD/CAM system in designing and fabricating the function-driven restorations could be an efficient way to obtain an satisfactory long-term outcome.
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Objective To study the influence of the convergence angle and cement space on the fit of CAD/CAM all-ceramic crowns.Methods The PMMA resin was produced in two groups,group A (2 degrees) and group B (4 degrees),30 in each group,and each group was divided into 3 sub-groups A 1,A2,A3;or B 1,B2,B3.Each subgroup included 10 patients with a CAD/CAM all-ceramic crown with PMMA resin generation type,but the cement space was 40 μm,60 μm,or 80 μm.The internal clearance edge of the double color silicone rubber impression reproduction technology of the all-ceramic crown was observed under the microscope.Analysis Micro-image software was used to measure the edge gap,and the resulting data were analyzed using SPSS 20.0 software.Results When the cement space is the same,the difference between 2 degrees and 4 degrees was statistically significant.Conclusion The fit is the best when the cement space is 60 μm and the convergence angle space is 4 degrees.
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Objective @#To compare the clinical effects of polymer ceramic onlay and all ceramic crown in short crown molars@*Methods @# 45 cases of polymer ceramic onlay and 45 cases of Zirconium dioxide all ceramic crowns which repaired the short crowm molars after root canal therapy were compared clinically from the aspects of beauty of restoration, fracture and dislodgement, marginal adaptation and the preservation of abutment teeth. @*Results @# One polymer ceramic onlay had fall out form the teeth after half year, while the all ceramic crowns have been 8 cases after 6~12 months. There were significant differences in fracture and dislodgement between the two groups (χ2=4.44, P < 0.05). @*Conclusion @# Polymer ceramic onlay has good clinical effects in the restoration of short crown molars.
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Objective:To evaluate the clinical performance of CAD/CAM zirconia all-ceramic restorations.Methods:287 all-ce-ramic Zirconia restorations in 206 patients were included in a 3-year prospectively survey with California Dental Association Standard (CDA)as a reference.The effects and the related factors such as restoration type,tooth region,fiber reinforced composite application on survival rate were analyzed.Kaplan-Meier survival analysis and Log-Rank test were used for data analysis.Results:Chipping frac-tures in 5 restorations,intense gingivitis at 4 restorations and periapical inflammation for 3 restorations were observed during the obser-vation period.The 3-year cumulative survival rate (CSR)of CAD/CAMzirconia restorations was 95.7%,The differences among the CSR of single crowns(96.3%),linked crowns (93.6%)and fixed partial dentures(95.7%)were not statistically significant(P >0.05).The difference was not statistically significant(P >0.05)between the CSR of the anterior region group(94.5%)and posterior region group(96.3%)as well as difference(P >0.05)between the CSR of fiber reinforced composite group (95.0%)and without fiber reinforced composite group(96.1%).Conclusion:The cumulative survival rate of CAD/CAM zirconia all-ceramic restorations is high.Chipping fracture is the main reason of failure.Restoration type,tooth region and fiber reinforced composite have no significant effect on the survival of zirconia restorations.
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The left lateral incisor with occlusal soreness of a 30-year old female was examined and treated.Radiographic examination re-vealed periradicular radiolucency around the apical and 3 canals.The 3 root canals were treated by root canal therapy,the tooth was restored by all-ceramic crown for the prevention of fracture.12 month follow-up showed that the treatment was effective.
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Objective:To explore the influence of the veneering porcelain thickness on the compressive strength of zirconia all-ceramic crown.Methods:25 zirconia basement crowns with the thickness of 0.5 mm were made by CAD-CAMsystem,and then were divided into 5 groups randomly with the veneering porcelain thickness of 0.5(A),1.0(B),1.5(C),2.0(D)and 2.5 mm(E)respectively. The compressive strength of the samples was measured by a testing machine.Statistical analysis was conducted by SPSS13.0 software. The microstructure of the fractured bonding interface of the specimens was observed by scanning electron microscope(SEM).Results:The compressive strength in group A,B,C,D and E were:(1 279.96 ±42.85)N,(2 235.44 ±50.14)N,(2 216.38 ±48.97)N, (2 169.22 ±60.40)N and (2 028.70 ±47.37)N respectively(A or E vs B,C or D,P 0.05;C vs D,P >0.05).SEMobservation found that in group A and E the bonding interface was uneven and loose,the cracks and spores in veneering porcelain appeared more and larger,and had a more intensive distribution.Conclusion:When the veneering porce-lain is too thick or too thin,the compressive strength of zirconia all-ceramic crown decreases,the thickness of the veneering porcelain should be controled in an appropriate range.
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PURPOSE: This in vitro study aimed to compare the failure load and failure characteristics of two different zirconia framework designs of premolar crowns when subjected to static loading. MATERIALS AND METHODS: Two types of zirconia frameworks, conventional 0.5 mm even thickness framework design (EV) and 0.8 mm cutback of full contour crown anatomy design (CB), were made for 10 samples each. The veneer porcelain was added on under polycarbonate shell crown made by vacuum of full contour crown to obtain the same total thickness of the experiment crowns. The crowns were cemented onto the Cobalt-Chromium die. The dies were tilted 45 degrees from the vertical plane to obtain the shear force to the cusp when loading. All crowns were loaded at the lingual incline of the buccal cusp until fracture using a universal testing machine with cross-head speed 0.5 mm/min. The load to fracture values (N) was recorded and statistically analyzed by independent sample t-test. RESULTS: The mean and standard deviations of the failure load were 1,170.1 +/- 90.9 N for EV design and 1,450.4 +/- 175.7 N for CB design. A significant difference in the compressive failure load was found (P<.05). For the failure characteristic, the EV design was found only cohesive failures within veneering porcelain, while the CB design found more failures through the zirconia framework (8 from 10 samples). CONCLUSION: There was a significant difference in the failure load between two designs, and the design of the framework influences failure characteristic of zirconia crown.
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Bicuspid , Crowns , Dental Porcelain , VacuumABSTRACT
PURPOSE: This in vitro study aimed to compare the failure load and failure characteristics of two different zirconia framework designs of premolar crowns when subjected to static loading. MATERIALS AND METHODS: Two types of zirconia frameworks, conventional 0.5 mm even thickness framework design (EV) and 0.8 mm cutback of full contour crown anatomy design (CB), were made for 10 samples each. The veneer porcelain was added on under polycarbonate shell crown made by vacuum of full contour crown to obtain the same total thickness of the experiment crowns. The crowns were cemented onto the Cobalt-Chromium die. The dies were tilted 45 degrees from the vertical plane to obtain the shear force to the cusp when loading. All crowns were loaded at the lingual incline of the buccal cusp until fracture using a universal testing machine with cross-head speed 0.5 mm/min. The load to fracture values (N) was recorded and statistically analyzed by independent sample t-test. RESULTS: The mean and standard deviations of the failure load were 1,170.1 +/- 90.9 N for EV design and 1,450.4 +/- 175.7 N for CB design. A significant difference in the compressive failure load was found (P<.05). For the failure characteristic, the EV design was found only cohesive failures within veneering porcelain, while the CB design found more failures through the zirconia framework (8 from 10 samples). CONCLUSION: There was a significant difference in the failure load between two designs, and the design of the framework influences failure characteristic of zirconia crown.
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Bicuspid , Crowns , Dental Porcelain , VacuumABSTRACT
PURPOSE: To investigate the influence of crown margin design on the stress distribution and to localize critical sites in maxillary canine under functional loading by using three dimensional finite element analysis. MATERIALS AND METHODS: The bite force of 100 N, 150 N, and 200 N was applied with an angulation of 45degrees to the longitudinal axis of tooth. Six models were restored with IPS e.max (Ivoclar Vivadent, Schaan, Liechtenstein) with a different margin design. With lingual ledge and various thicknesses, three different core ceramics were designed in each model. RESULT: In the core ceramic, the maximum tensile stresses were found at the labiocervical region. In the veneering ceramic the maximum tensile stresses were found at the area where the force was applied in all models. CONCLUSION: Shoulder and chamfer margin types are acceptable for all-ceramic rehabilitations. A ledge on the core ceramic at cervical region may affect the strength of all-ceramic crowns.
Subject(s)
Axis, Cervical Vertebra , Bite Force , Ceramics , Crowns , Finite Element Analysis , Shoulder , ToothABSTRACT
Occlusal plane is a sagittal expression of dental arch form, and it composes the shape of occlusion, which is one of the most important elements of Maxillo-oral system. In this case, vertical, horizontal coordinates of bionic-median-sagittal plane was produced in articulator, and to achieve relation of left and right position of upper, lower teeth and deficits in alveola, Shilla system was used to reconstruct occlusal plane. In this case, a 41 year-old male patient visited for fracture of 10 unit metal-ceramic fixed partial denture of upper anterior teeth and for overall treatment. Clinical, radiographical, model examination was held, full mouth rehabilitation was achieved by placing dental implant. Maxillo-oral relation was recorded using Gothic arch Tracer complex and were mounted. And for the next step, we estimated original occlusal plane using Shilla system. After analysis we produced diagnosis wax pattern. On the basis of this, radiography stent was manufactured and dental implant was placed, and temporary prosthesis was made by using diagnosis wax pattern. Cross mounting and anterior guiding table were performed in order to reproduce temporary restoration morphology and bite pattern, followed by final restoration made of all ceramic crown with zirconia coping. As stated above, appropriately esthetic and functional results can be seen in using Shilla system in diagnosis and treatment procedure of full mouth rehabilitation patient.
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Humans , Male , Bites and Stings , Ceramics , Crowns , Dental Arch , Dental Articulators , Dental Implants , Dental Occlusion , Denture, Partial, Fixed , Mouth , Mouth Rehabilitation , Prostheses and Implants , Stents , Tooth , ZirconiumABSTRACT
PURPOSE: All-ceramic crowns are subject to fracture during function. To minimize this common clinical complication, zirconium oxide has been used as the framework for all-ceramic crowns. The aim of this study was to compare the fracture strengths of two computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia crown systems: Lava and Digident. MATERIALS AND METHODS: Twenty Lava CAD/CAM zirconia crowns and twenty Digident CAD/CAM zirconia crowns were fabricated. A metal die was also duplicated from the original prepared tooth for fracture testing. A universal testing machine was used to determine the fracture strength of the crowns. RESULTS: The mean fracture strengths were as follows: 54.9 +/- 15.6 N for the Lava CAD/CAM zirconia crowns and 87.0 +/- 16.0 N for the Digident CAD/CAM zirconia crowns. The difference between the mean fracture strengths of the Lava and Digident crowns was statistically significant (P<.001). Lava CAD/CAM zirconia crowns showed a complete fracture of both the veneering porcelain and the core whereas the Digident CAD/CAM zirconia crowns showed fracture only of the veneering porcelain. CONCLUSION: The fracture strengths of CAD/CAM zirconia crowns differ depending on the compatibility of the core material and the veneering porcelain.
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Ceramics , Collodion , Crowns , Dental Porcelain , Tooth , ZirconiumABSTRACT
Earlier Metal ceramic crowns were the restorations of choice in the management of traumatic tooth fractures. However, the inherent drawbacks of metal ceramic restorations and the development of newer all ceramic alternatives have resulted in superior esthetic and functional management of these clinical situations. The following case series describes the management of traumatic tooth fractures with Zirconia based all ceramic restorations following endodontic therapy.
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Objective To reconstruct three-dimensional finite element analysis all-ceramic crowm model of the first maxillary molar.Methods After the CT scanning and image processing to the first maxillary molar in vivo,a 3-D geometric model was established by the Imageware software.The mesh model was then built in Abaqus,the finite element analysis software.Result The three dimensional finite element all-ceramic crown models of the first maxillary molar was constructed on the computer,which had 60 160 nodes and 186 328 tetrahedrons elements.Conclusion The finite element model constructed has the advantages of intact structure and precise elements,can simulate the natural condition and facilitate the further biomechanical research.
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Restauração de dentes tratados endodonticamente constituidesafio permanente na odontologia, uma vez que aspectos biomecânicos,estéticos e complexidade de execução técnica podemresultar em insucesso com consequente perda do elemento dentário.Geralmente dentes tratados endodonticamente se encontramenfraquecidos devido à perda de estrutura dentária o queresulta em redução de resistência mecânica da dentina. Estesfatores resultando em maiores riscos de falhas biomecânicasquando comparados aos dentes com vitalidade pulpar. Este trabalhotem por objetivo apresentar procedimentos clínicos reabilitadorespara devolução de harmonia estética com ênfase emprocedimentos realizados em incisivo central superior com extensaperda de estrutura coronária e restauração em resina compostainsatisfatória. Foi empregada a associação de pino de fibrade vidro (Exacto, Ângelus) e resina composta para reconstruçãointerna seguido de coroa em cerâmica pura (In Ceram Alumina,Vita). São destacados os passos clínicos e breve revisão de aspectosbiomecânicos e estéticos desta alternativa reabilitadora.
Restoration of endodontically treated teeth is a challenge inoperative dentistry, since the biomechanical, aesthetic and complexityof the technique can result in failure with subsequenttooth loss. Generally endodontically treated teeth are weakeneddue to loss of tooth structure and reduce the mechanicalstrength of dentin. These factors result in a higher risk of biomechanicalfailure when compared to teeth with pulp vitality.This paper aims to present clinical rehabilitation procedures torecover the smile harmony with an emphasis on aesthetic proceduresperformed in the maxillary central incisor with extensiveloss of coronal tooth tissue and unsatisfactory compositeresin restoration. It was employed the combination of fiberglasspost (Exacto, Angelus) and coronal reconstruction with compositeresin followed by all ceramic alumina crown (In CeramAlumina, Vita). Highlights the clinical steps and brief review ofbiomechanical and aesthetic rehabilitation of this alternative aredescribed.
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OBJECTIVE: This study investigated the durability of repaired all-ceramic crowns after cyclic loading. MATERIAL AND METHODS: Eighty In-ceram zirconia crowns were fabricated to restore prepared maxillary premolars. Resin cement was used for cementation of crowns. Palatal cusps were removed to simulate fracture of veneering porcelain and divided into 4 groups (n = 20). Fracture site was treated before repair as follows: roughening with diamond bur, (DB); air abrasion using 50 µm Al2O3, (AA) and silica coating using Cojet system followed by silane application, (SC). Control group (CG) 20 specimens were left without fracture. Palatal cusps were repaired using composite resin. Specimens were stored in water bath at 37ºC for one week. Ten specimens of each group were subjected to cyclic loading. Fracture load (N) was recorded for each specimen using a universal testing machine. Two-way analysis of variance (ANOVA) and Tukey honestly significant difference (HSD) test (a=.05) were used for statistical analysis. RESULTS: There was statistically significant difference between control and tested groups, (p<0.001). Post Hoc analysis with the Tukey HSD test showed that cyclic loading fatigue significantly decreased means fracture load of control and test groups as follows (CG, 950.4±62.6 / 872.3±87.4, P = 0.0004), (DB, 624.2 ±38 / 425.5± 31.7, P <.001), (AA, 711.5 ±15.5 / 490 ± 25.2, p <0.001) and (SC, 788.7 ± 18.1 / 610.2 ± 25.2, P <.001), while silica coating and silane application significantly increased fracture load of repaired crowns (p<0.05). CONCLUSION: Repair of fractured In-ceram zirconia crowns after chairside treatment of the fracture site by silica coating and silane application could improve longevity of repaired In-ceram zirconia crowns.
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Humans , Crowns , Dental Porcelain , Dental Prosthesis Repair , Analysis of Variance , Bicuspid , Coated Materials, Biocompatible , Composite Resins , Dental Stress Analysis , Silanes , Silicon Dioxide , Statistics, Nonparametric , Surface Properties , ZirconiumABSTRACT
Objective To investigate the clinical effect of glassfiber post with all-ceramic-crown for incisors restoration, providing some references for our clinical application. Methods 82 patients (100 teeth defect) in our department from October,2008 to October, 2009 were divided into group A and group B with 50 incisors in each. Glassfiber post with all - ceramic - crown was used in group A, and metal post with porcelain-fused-to-metal in group B. After one year follow-up, we observed the clinical effect. Results 49 cases were effective and 1 case failed in group A. 42 cases were effective and 8 cases failed in group B.There was statistically significant difference between the two groups. Conclusions Glassfiber post with all-ceramic-crown is better in convenient handling and good colour for incisors compared to metal post with porcelain-fused-to-metal.
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STATEMENT OF PROBLEM: Recently, there have been increased esthetic needs for posterior dental restorations. The failure of posterior dental ceramic restoration are possible not only by the characters of the component materials but also by the type of food. PURPOSE: The research aim was to compare the in vitro fracture resistance of simulated first molar crowns fabricated using 4 dental ceramic systems, full-porcelain-occlusal-surfaced PFG, half-porcelain-occlusal-surfaced PFG, Empress 2, Ice Zirkon and selected Korean foods. MATERIAL AND METHODS: Eighty axisymmetric crowns of each system were fabricated to fit a preparation with 1.5- to 2.0-mm occlusal reduction. The center of the occlusal surface on each of 15 specimens per ceramic system was axially loaded to fracture in a Instron 4465, and the maximum load (N) was recorded. Afterwards, selected Korean foods specimens (boiled crab, boiled chicken with bone, boiled beef rib, dried squid, dried anchovy, round candy, walnut shell) were prepared. 15 specimens per each food were placed under the Instron and the maximum fracture loads for them were recorded. The 95% confidence intervals of the characteristic failure load were compared between dental eramic systems and Korean foods. Afterwards, on the basis of previous results, 14Hz cyclic load was applied on the 4 systems of dental ceramic restorations in MTS. The reults were analyzed by analysis of variance and Post Hoc tests. RESULTS: 95% confidence intervals for mean of fracture load 1. full porcelain occlusal surfaced PFG Crown: 2599.3 to 2809.1 N 2. half porcelain occlusal surfaced PFG Crown: 3689.4 to 3819.8 N 3. Ice Zirkon Crown: 1501.2 to 1867.9 N 4. Empress 2 Crown: 803.2 to 1188.5 N 5. boiled crab: 294.1 to 367.9 N 6. boiled chicken with bone: 357.1 to 408.6 N 7. boiled beef rib: 4077.7 to 4356.0 N 8. dried squid: 147.5 to 190.5 N 9. dried anchovy: 35.6 to 46.5 N 10. round candy: 1900.5 to 2615.8 N 11. walnut shell: 85.7 to 373.1 N under cyclic load (14Hz) in MTS, fracture load and masticatory cycles are: 1. full porcelain occlusal surfaced PFG Crown fractured at 95% confidence intervals of 4796.8 - 9321.2 cycles under 2224.8 N (round candy)load, no fracture under smaller loads. 2. half porcelain occlusal surfaced PFG Crown fractured at 95% confidence intervals of 881705.1 - 1143565.7 cycles under 2224.8 N (round candy). no fracture under smaller loads. 3. Ice Zirkon Crown fractured at 95% confidence intervlas of 979993.0 - 1145773.4 cycles under 382.9 N (boiled chicken with bone). no fracture under smaller loads. 4. Empress 2 Crown fractured at 95% confidence intervals of 564.1 - 954.7 cycles under 382.9 N (boiled chicken with bone). no fracture under smaller loads. CONCLUSION: There was a significant difference in fracture resistance between experimental groups. Under single load, Korean foods than can cause fracture to the dental ceramic restorations are boiled beef rib and round candy. Even if there is no fracture under single load, cyclic dynamic load can fracture dental posterior ceramic crowns. Experimental data with 14 Hz dynamic cyclic load are obtained as follows. 1. PFG crown (full porcelain occlusion) was failed after mean 0.03 years under fracture load for round candy (2224.8 N). 2. PFG crown(half porcelain occlusion) was failed after mean 4.1 years under fracture load for round candy (2224.8 N). 3. Ice Zirkon crown was failed after mean 4.3 years under fracture load for boiled chicken with bone (382.9 N). 4. Empress 2 crown was failed after mean 0.003 years under fracture load for boiled chicken with bone (382.9 N).
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Candy , Ceramics , Chickens , Crowns , Decapodiformes , Dental Porcelain , Ice , Juglans , Lithium Compounds , Molar , RibsABSTRACT
PURPOSE: The purpose of this study is to compare three different CAD/CAM systems through the fracture strength of zirconia core and to evaluate the clinical availability of each system. MATERIAL AND METHODS: The following three groups of 30 maxillary mesial incisor core for all-ceramics(each group 10) were fabricated as follows: group 1. Adens(R) CAD/CAM system, group 2. Cerasys(R) CAD/CAM system, group 3. 3M LAVA(R)CAD/CAM system. All specimens were manufactured consistently thickness 0.5mm and relief 40 micrometer. Specimens were subjected to compressive loading on the lingual area by Z250/SN5S(R). Each group's mean and standard deviation were calculated and Kruskal Waillis test, Wilcoxon Rank Sum test were utilized to find out the relationship among the groups. RESULTS: The results were as follows: 1. The mean fracture strength of Adens(R) system was 615.89+/-156.1N, the Cerasys(R) system was 863.98+/-151.5N, and the 3M LAVA(R) system was 1143.1+/-286.6N. 2. The fracture strength of the systems showed the significant statistical differences in order of 3M LAVA(R) system, Cerasys(R) system, Adens(R) system. CONCLUSION: In this study, in spite of the differences among the groups, every group showed clinically useful results. It is necessary to study further clinical experiments on a long term basis.