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BACKGROUND/PURPOSE: Ceramic restorations have been increasingly applied over recent years. But the performance of cement is still unknown after cementation. This study was aimed to compare the compressive strength and the performances of three different types of composite resin after lithium disilicate inlay cementation. MATERIALS AND METHODS: Twenty-four human maxillary premolars were embedded in resin blocks, finished a MOD inlay preparation and scanned with an extraoral scanner. Lithium disilicate ceramic inlays (IPS e.max, Ivoclar Vivadent, Liechtenstein) were fabricated according to the scanner's model. All the specimens were then etched, bonded, and cemented with three different composite resins. Right after 5000 thermal cyclings, the specimens were accepted compressive tests to evaluate the compressive strength and failure types. Moreover, the fracture fragments of the specimens were examined using scanning electron microscopy (SEM) to verify the fracture type. RESULTS: Dual-cured resin cement (Rely X Ultimate) showed the highest compressive strength (1002 ±â€¯508 N), followed by the light-cured flowable resin (Z350 XT) (971 ±â€¯209 N) and light-cured bulkfill (Filtek Bulkfill) resin (581 ±â€¯191 N). Type IV (root fracture) failures in the dual-cured resin cement group was 25%, and light-cured flowable resin was 37.5%. But none of type IV fracture was found in the light-cured bulkfill flowable group. CONCLUSION: Dual-cured resin cement demonstrates the highest compressive strength after ceramic inlay cementation. Light-cured bulkfill resin shows the lowest compressive strength, but catastrophic failure is absent in this group.

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Ceramic fracture and debonding are the primary failures that follow ceramic inlay and can lead to stress and tooth fracture. In this study, we examined two designs-concave and flat-of the gingival cavity bottom for tooth cavities restored using ceramic inlays. We investigated the biomechanical behavior of ceramic inlay-restored teeth (concave and flat) through three-dimensional finite element analysis (FEA) and experimentally validated the results using an ultrahigh-speed camera. We conducted in vitro real-time recording of the deformation of a restored tooth during loading using an ultrahigh-speed camera. This technique enables further image registration to observe deformation variation and vector fields. The deformation vector fields revealed that the concave design moved the deformation toward the buccal side of the cavity bottom, whereas the flat design moved it toward the palatal side. These findings correlated with the FEA results, which indicated that the concave design constrained stress in the dentin cavity and relieved palatal stress. Our results suggest that incorporating a concave design in cavity preparation can improve the fracture resistance of ceramic inlay-restored teeth, preventing unrestorable fractures. The current study is the first to utilize an ultrahigh-speed camera in dental biomechanics, and such cameras are useful for nondestructive and dynamic analysis. STATEMENT OF SIGNIFICANCE: First utilize ultrahigh-speed cameras in dental biomechanics analysis. Tooth fracture videos captured by ultrahigh-speed camera helps us learn fracture mechanics in between tooth cavity design and ceramic inlay. Concave design leads to stress in safer areas that causes a less damaging fracture. Minimal invasive preparation by concave design strengthens tooth fracture resistance. Non-destructive data from ultrahigh-speed cameras combined with FEA can get more insight into how the stress and strain derived in biomaterials.

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Objective:To investigate the curative effect of different restorations for deciduous teeth defect of children.Methods:67 children with teeth defecting seriously and being unable to fill restore were enrolled from January 2011 to January 2015 and randomly divided into three groups,one group of patients accepted metal crown restoration (Group A,n=22),one group adopted ceramic inlay restoration (Group B,n=22),and the last one accepted silver amalgam filling (Group C,n=23),the curative effect and incidence of adverse reactions among three groups in the period follow-up were compared.Results:In the period of 18-month follow-up,6 patients of toothache,5 patients of food impaction and crevices between restorations and teeth,3 cases of gingival congestion,2 cases of secondary caries were observed in group C;3 cases of toothache,1 case of food impaction,gingival congestion,crevices between restorations and teeth and secondary caries were observed in group B;2 cases of toothache and food impaction,1 case of gingival congestion were observed in group A.The incidence of adverse reactions in group A and group B was lower than those in group C (P＜0.05),which was lower in group A than that in group B,but no significant difference was found between group A and group B (P＞0.05).Conclusion:The restoration of metal crown and ceramic inlay deserved popularization had better curative effect and safety for deciduous teeth defect of children than silver amalgam filling.

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Objective To evaluate the clinical effect of CEREC chairside on atypical porcelain inlay restoring class [[cavity.Methods 30 patients that required re-treatment because of resin restoration failure and early posterior proximal caries were selected randomly.The original fillings,secondary carious tissues and undercut parts were removed.The clear and round edge lines were prepared.With Sirona CEREC Blocs,35 atypical ceramic inlays were produced in accordance with CEREC AC CAD/CAM standard procedures.After clinical trial and modification,the inlays were bonded with 3M Veneer resin adhesive cement.Evaluation was done immediately and 3,6,12 and 24 months after restoration.Two senior prosthodontists did the evaluation according to the modified USPHS criteria.Results The evaluation results were all A when estimated immediately after restoration.None inlay falled off during the first two years.However,3 inlay were found to be damaged when reviewed at the 24th month.There exsited two patients having mild symptoms of dentine hypersensitivity which appeared at the beginning and died out gradually.Generally speaking,more than 90％ of inlay restorations had reached the USPHS criteria A.Color match and retention represented better effects.Conclusions CEREC atypical ceramic inlays can effectively restore Class Ⅱ cavity,short-term effect is good,but long-term effect still needs further observations.

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The aim of this study was to investigate bonding effectiveness in direct restorations. A two-step self-etch adhesive and a light-cure resin composite was compared with luting with a conventional dual-cure resin cement and a two-step etch and rinse adhesive. Class-I box-type cavities were prepared. Identical ceramic inlays were designed and fabricated with a computer-aided design/computer-aided manufacturing (CAD/CAM) device. The inlays were seated with Clearfil SE Bond/Clearfil AP-X (Kuraray Medical) or ExciTE F DSC/Variolink II (Ivoclar Vivadent), each by two operators (five teeth per group). The inlays were stored in water for one week at 37°C, whereafter micro-tensile bond strength testing was conducted. The micro-tensile bond strength of the direct composite was significantly higher than that from conventional luting, and was independent of the operator (P<0.0001). Pre-testing failures were only observed with the conventional method. High-power light-curing of a direct composite may be a viable alternative to luting lithium disilicate glass-ceramic CAD/CAM restorations.

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Objective To analyze the living polymerization porcelain inlay restoration dental pulp large clinical efficacy of dental defects and infection prevention. Methods Forty-two cases patients with dental defects after the live pulp tooth of large teeth 48, were randomly divided into experimental group (24 teeth) and the control group (24 teeth). The experimental group tooth preparation, polymerization porcelain inlay restoration; Control group metal ceramic crowns, resin adhesive application RelyX Unicem 2-year follow-up and evaluated of the efficacy analysis infection prevention methods. Results The color matching, shape matching, secondary caries, marginal fit, wear and fracture strengths in the experimental group were better than the control group, the difference was statistically significant (P<0.05). Conclusion Living polymerization porcelain inlay restoration dental pulp excellent clinical efficacy large area of dental defects, pa-tients followed up show functions fine roles in shape, color matching after 2 years.

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OBJECTIVES: In the present study, lithium-disilicate ceramic inlays should be analyzed biomechanically according to their thickness and dimension, and it should be clarified as to whether there is a significant relationship between the inlay volume and the induced tensile stress level. METHODS: Using a new parametric CAD modeling procedure, 27 lithium-disilicate ceramic inlays with various parameters of "depth", "width", "angle" and restoration volume were generated. These inlays were integrated into the CAD model of a lower molar created from the CT data of an anatomical preparation. The resulting CAD models were, finally, three-dimensionally cross-linked to FEM models. After applying a compressive force of 200 N, Principal Tensile Stresses (PTSs) could be measured in the inlay. The values were subject to statistical analysis afterwards. RESULTS: The volume of the inlay restorations varied between 35.7 mm(3) and 82.5mm(3). The maximum PTS values (n=10) only showed a slight negative correlation with the inlay volume. The correlation coefficient according to Spearman was -0.082 (p ≤ 0.001). If the highest 1000 PTS values of each inlay were considered (n=1000), the correlation coefficient was further reduced to +0.068 (p ≤ 0.001). No significant correlation between the inlay volume and the induced PTS level could be detected. SIGNIFICANCE: Under the conditions and limitations of the present FEM study, the inlay volume did not significantly influence the tensile stress level of ceramic inlays. The results may support the thesis that volume-reduced all-ceramic inlays might not have an increased fracture risk. Further studies are needed to confirm this.

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PURPOSE: The purpose of this study was to evaluate the bond strengths between the latest CAD/CAM ceramic inlay and various resin cements which are used primarily for esthetic restoration. MATERIALS AND METHODS: Cylindrical ceramic blocks(Height: 5 mm, diameter: 3 mm) were fabricated by using Cerec3 and bonded on the dentin of the ninety extracted caries-free molars using three different kinds of resin cement(Unicem(R), Biscem(R), and Variolink II(R)) according to the manufacturer's instructions. Ninety specimens were divided into 3 groups according to three different kinds of resin cement. Half of each group were conducted thermocycling under the conditions of the 5 - 55degrees C, 5,000 cycle but the other half of them weren't. All specimens were kept in normal saline 37degrees C, for 24 hours before measuring the bond strength. The shear bond strength was measured by Universal testing machine with a cross head speed of 0.5 mm/min. The results were analyzed statistically by t-test and one-way ANOVA. RESULTS: Unicem(R) group showed the highest shear bond strength despite a slight decline by thermocycling. The shear bond strength of Unicem(R) group and ValiolinkII(R) group were significantly influenced by thermocycling, whereas Biscem(R) group was not influenced (P<.05). There were no significant differences in the bond strength between the three groups without thermocycling, but there was significant differences between Unicem(R) group and Valiolink II(R) group with thermocycling(P<.05). CONCLUSION: It has been shown to be clinically effective when the self-adhesive resin cements Unicem(R) and Biscem(R) were used instead of the etch-and-rinse resin cement Valiolink II(R) during the bonding of CAD/CAM ceramic inlay restorations with teeth.

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Objective To study the effect of CEREC CAD/CAM ceramic inlay on repair of wedge-shaped defects of teeth and test its anti-fracture properties. Methods Extracted teeth were divided into control group ( n = 16) and experimental group ( n = 16) ,and prepared into imitating teeth with wedge-shaped defects. Teeth in experimental and control groups were repaired with CEREC CAD/CAM ceramic inlay and light-cured composite resin,respectively. Anti-fracture strength of teeth with wedge-shaped defects repaired with CEREC CAD/CAM was assayed on a universal testing device with its maximal loading recorded. The anti-fracture strength was compared between the 2 groups. Results The anti-fracture strength of teeth with wedge-shaped defects repaired with CEREC CAD/CAM ceramic inlay was significantly higher in experimental group than in control group ( 3. 56 ? 0. 27 vs 2. 43 ? 0. 15,P