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@#All-ceramic restorations are widely used in oral restoration because of their beauty and high strength. Glass ceramics and zirconia all-ceramic materials are the two most widely used all-ceramic materials in the clinic. However, when all-ceramic restorations need to be removed due to marginal microleakage and secondary caries, its high strength and high bonding strength greatly increase the difficulty of removal. In recent years, clinicians have tried to use Er: YAG lasers to remove all-ceramic restorations. The Er: YAG laser can be safely and efficiently applied to the removal of glass restorations, and it can also play a role in thinner zirconia restorations. Various factors, such as the material and thickness of the all-ceramic restoration, the type of cement, and the laser power, can affect the speed of removal of the Er: YAG laser. However, the current research is limited to case reports and in vitro studies, lacking systematic clinical research. The specific mechanism of Er: YAG laser removal of all-ceramic restorations and the influence of laser frequency, adhesive type, and abutment on the removal speed need to be further demonstrated by follow-up research.
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Objective To investigate the effect of different adhesive materials on all-ceramic restoration. Methods The all-ceramic restoration system model of mandibular first molar was established by spiral computed tomography (CT) scanning and computer-aided design (CAD) modeling. Four types of resin adhesive materials (Duo Cement,Lute-It,Rely-X ARC,Variolink II) used in clinics were selected, and the stress distribution was calculated using the ABAQUS software. Results The stress at the bonding interface was the highest when low filler adhesive Lute-It was used. Based on the viscoelasticity analysis, resin adhesives with a larger storage modulus and loss modulus could yield lower stress extremes. Conclusions The study suggests that high-filler type resin adhesives with a large energy storage modulus and loss modulus should be used clinically.
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Objective@#To investigate the failure reasons of all-ceramic restorations fabricated with chair-side CAD-CAM technology (CEREC®) and to improve the clinical survival of all-ceramic restorations. @*Methods @#All-ceramic single-tooth restorations of CEREC® in stomatology hospital of Jiangsu province between 2013 and 2016 were summarized. By clinical examination and CEREC Biogeneric surveying, the failure reasons and related restoration types were evaluated. These results were analyzed with Chi-square test and Spearman correlation analysis. @*Results@#A total of 61 cases with restoration types of 11 inlays, 38 onlays, 2 endocrowns, and 11 all-crowns, resulted in a failure rate of 5.4% in all-ceramic single-tooth restorations in 1-4 years follow-up. The reasons for failure included ceramic fracture (n=33), debonding (n=13), tooth fracture (n=15), which attributed to thin ceramic thickness (n=27), acute line angle (n=6), insufficient enamel bulk (n=3), insufficient retention type (n=10), insufficient resistance type (n=15).@*Conclusion @# The most common reason for failure in CEREC® restorations was insufficient preparation space in occlusal surface.
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Objective To explore the clinical application of digital chair?side immediate all?ceramic restoration system,design and fabricate inlays and onlays to restore the large?defected molars,and to analyze and evaluate the efficacy of this clinical restoration. Methods Totally 84 inlays and 65 onlays were fabricated with IPS e.max CAD series ceramic blocks by using Cerec AC system to conduct immediate all?ceramic restorations of 149 teeth for 108 patients. The inlays and onlays were applied and cemented to the prepared teeth with dual?cured resin luting agent. The restored molars were re?examined by two dentists after six months. The analysis standard was based on the United States Public Health Service(USPHS criteria) and the results were statistically analyzed(α=0.05). Results There was no statistically significant difference in the case numbers of grade A and grade B for each index comparing the immediate condition to the condition after 6 months. Over 90 percent of ceramic inlays and onlays were quali?fied to be grade A. The restorations were well in the aspects of anatomic morphology,marginal integrity,color match,marginal discoloration,reten?tion,gingival health and secondary caries. Conclusion Computer aided design/computer aided manufacture(CAD/CAM)system combined with machinable glass ceramics can achieve a favorable result in restoration of large?defected teeth. Digital chair?side immediate all?ceramic restoration technique is an ideal solution for large?defected tooth restoration.
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Objective:To evaluate the influence of cervical collar height on the compressive strength of CAD/CAMzirconia-ceramic restoration.Methods:Zirconia cores were manufactured and divided into 5 groups (n =1 0)based on the cervical collar height(mm):0.0(A),1 .0(B),1 .5(C),2.0(D)and 2.5(E).After veneered with porcelain,all the samples were cemented on the metal tooth analog and then mounted in an universal test machine.The force was applied at a crosshead speed of 1 mm/min until catastrophic fail-ure occurred.Fracture loads and failure modes were recorded.Results:Mean of the fracture strength values(kN)in group A,B,C, D and E were 0.95 ±0.39,1 .29 ±0.50,1 .54 ±0.28,2.04 ±0.1 9 and 2.27 ±0.53 respectively(among groups,P <0.05).Two types of fracture modes were observed:chipping of the veneering porcelain and fracture of the veneering porcelain together with the framework.Conclusion:Zirconia coping design with 1 .5 mm cervical collar height may increase the compressive strength of CAD/CAMzirconia-ceramic restoration.
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PURPOSE: The objective of this study was to evaluate the clinical acceptability of all-ceramic crowns fabricated by the digital veneering method vis-a-vis the traditional method. MATERIALS AND METHODS: Zirconia specimens manufactures by two different manufacturing method, conventional vs digital veneering, with three different thickness (0.3 mm, 0.5 mm, 0.7 mm) were prepared for analysis. Color measurement was performed using a spectrophotometer for the prepared specimens. The differences in shade in relation to the build-up method were calculated by quantifying DeltaE* (mean color difference), with the use of color difference equations representing the distance from the measured values L*, a*, and b*, to the three-dimensional space of two colors. Two-way analysis of variance (ANOVA) combined with a Tukey multiple-range test was used to analyze the data (alpha=0.05). RESULTS: In comparing means and standard deviations of L*, a*, and b* color values there was no significant difference by the manufacturing method and zirconia core thickness according to a two-way ANOVA. The color differences between two manufacturing methods were in a clinically acceptable range less than or equal to 3.7 in all the specimens. CONCLUSION: Based on the results of this study, a carefully consideration is necessary while selecting upper porcelain materials, even if it is performed on a small scale. However, because the color reproducibility of the digital veneering system was within the clinically acceptable range when comparing with conventional layering system, it was possible to estimate the possibility of successful aesthetic prostheses in the latest technology.
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Crowns , Dental Porcelain , Prostheses and ImplantsABSTRACT
Objective To analyze the relationship between alexithymia and patients' satisfaction under the condition of good quality in the esthetic characters. Methods 211 patients requiring single anterior tooth restoration were treated with all ceramic crowns which were assessed by the good and moderate degrees. Patients received 20-item Toronto Alexithymia Scale (TAS-20) and a visual analogue scale assessing patients' satisfaction (VAS). Chi-squared analysis, correlation analysis and the general linear modeling procedure were calculated for TAS total and factors scores according to age, gender and dichotomized satisfaction. Results 85. 3% patients belonged to the high satisfaction group(VAS scores 80 or higher) and 7.1% reported alexithymia ( total score 61 or higher). No difference across gender was observed in the prevalence of alexithymia and satisfaction. Age was correlated with the TAS scores ( r=0.629) and satisfaction scores ( r= -0.429). According to dichotomized satisfaction,TAS total and factor 1&2 scores were significantly different. When adjusting for the effect of age,the association was existed between TAS scores and san'sfaction( r= -0.68). Conclusion Alexithymia has effect on dental satisfaction.
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PURPOSE: The purpose of this study was to compare the wear characteristics of human enamel opposing 2 heat-pressed ceramics (e.max Press and Empress Esthetic), conventional feldspathic porcelain (Ceramco 3) and type III gold alloy. MATERIAL AND METHODS: Intact cusps of extracted premolars were used for enamel specimens. Five disk samples were made for each of two heat-pressed ceramics groups, conventional feldspathic porcelain group and type III gold alloy group. Wear tests were conducted in distilled water using a pin-on-disk tribometer. The amount of enamel wear was determined by weighing the enamel specimens before and after wear tests, and the weight was converted to volumes by average density. The wear tracks were analyzed by scanning electron microscopy and surface profilometer to elucidate the wear characteristics. RESULTS: 1. Ceramco 3 led to the greatest amount of enamel wear followed by Empress Esthetic, e.max Press and type III gold alloy. However, there was no significant difference between Ceramco 3 and Empress Esthetic (P > .05), and there were also no significant differences among Empress Esthetic, e.max Press and type III gold alloy (P > .05). 2. The average surface roughness of e.max Press after wear test was smallest followed by Empress Esthetic and Ceramco 3, but there was no significant difference between Empress Esthetic and Ceramco 3 (P > .05). 3. There were no significant differences among the depth of wear tracks of all the groups (P > .05). The group that showed the largest width of wear track was Ceramco 3 followed by Empress Esthetic, e.max Press and type III gold alloy. However, there was no significant difference between e.max Press and Empress Esthetic (P > .05), and there was also no significant difference between Empress Esthetic and Ceramco 3 (P > .05). CONCLUSION: Within the limits of this study, heat-pressed ceramics were not more abrasive than conventional feldspathic porcelain.
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Humans , Alloys , Bicuspid , Ceramics , Dental Enamel , Dental Porcelain , Microscopy, Electron, Scanning , Track and Field , WaterABSTRACT
PURPOSE: Marginal fit is one of the important components for the successful prosthodontic restoration. Poor fitting margin of the restoration causes hypersensitivity, secondary caries, and plaque accumulation, which later result in prosthodontic failure. CAD/CAM zirconia all-ceramic restorations, such as LAVA(R) (3M ESPE, St.Paul, MN) and EVEREST(R) (KaVo Dental GmbH, Biberach, Germany) systems were recently introduced in Korea. It is clinically meaningful to evaluate the changes of the marginal fit of the CAD/CAM zirconia systems before and after build-up. The purposes of this study are to compare the marginal fit of the two CAD/CAM all-ceramic systems with that of the ceramometal restoration, before and after porcelain build-up. MATERIAL AND METHODS: A maxillary first premolar dentiform tooth was prepared with 2.0 mm occlusal reduction, 1.0 mm axial reduction, chamfer margin, and 6 degree taperness in the axial wall. The prepared dentiform die was duplicated into the metal abutment die. The metal die was placed in the dental study model, and the full arch impressions of the model were made. Twenty four copings of 3 groups which were LAVA(R), EVEREST(R), and ceramometal restorations were fabricated. Each coping was cemented on the metal die with color-mixed Fit-checker II(R) (GC Cor., Tokyo, Japan). The marginal opening of each coping was measured with Microhiscope(R) system (HIROX KH-1000 ING-Plus, Seoul, Korea. *300 magnification). After porcelain build-up, the marginal openings of LAVA(R), EVEREST(R),and ceramometal restorations were also evaluated in the same method. Statistical analysis was done with paired t-test and one-way ANOVA test. RESULTS: In coping states, the mean marginal opening for EVEREST(R) restorations was 52.00 +/- 11.94 micrometer, for LAVA(R) restorations 56.97 +/- 10.00 micrometer, and for ceramometal restorations 97.38 +/- 18.54 micrometer. After porcelain build-up, the mean marginal opening for EVEREST(R) restorations was 61.69 +/- 19.33 micrometer, for LAVA(R) restorations 70.81 +/- 12.99 micrometer, and for ceramometal restorations 115.25 +/- 23.86 micrometer. CONCLUSION: 1. LAVA(R) and EVEREST(R) restorations in comparison with ceramometal restorations showed better marginal fit, which had significant differences (P .05). 3. EVEREST(R), LAVA(R) and ceramometal restorations showed a little increased marginal opening after porcelain build-up, but did not show any statistical significance (P > .05).
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Bicuspid , Dental Porcelain , Hypersensitivity , Korea , Prosthodontics , Silicones , Tokyo , Tooth , ZirconiumABSTRACT
The purpose of this study was to evaluate marginal fit of four all-ceramic crown systems 1) conventional In-Ceram, 2) copy-milled In-Ceram using Celay system, 3) IPS Empress, 4) OPC(Optimal Pressable Ceramic). All ceramic crowns were made on epoxy dies. The fabricated crowns were sandblasted, cleaned with ultrasonic cleansing, silanated, and cemented with Bistite composite resin cement. The selected marginal areas of the crowns were the labial, lingual, mesial, and distal surface. Each selected area of surface was 0.6Xl.6mm in dimension. The image of each marginal area was captured to computer files using DT-55 Frame Grabber and light microscope connected CCD camera. The marginal gaps were measured every 70mm using computer image analysis program. The results obtained were summarized as follows : 1. The marginal fit of four all-ceramic crowns were significantly different from each other(p<0.01), and mean marginal fit values obtained were 31.42 +/- 16.52mm in conventional In-Ceram, 55.45 +/- 27.90mm in copy-milled In-Ceram using Celay-system, 44.36 +/- 24.59mm in IPS Empress, 47.21 +/- 20.42mm in OPC. 2. In the marginal fit of conventional In-Cerani and copy-milled In-Ceram crowns using Celay-system there was no significant difference between mesiodistal and buccolingual surface. but in the marginal fit of IPS Empress and OPC crowns, there was significant difference between mesiodistal and buccolingual surface(p <0.01). 3. The marginal fit of four hinds of all-ceramic crowns was clinically acceptable.