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1.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 38(6): 647-651, 2020 Dec 01.
Artículo en Chino | MEDLINE | ID: mdl-33377341

RESUMEN

OBJECTIVE: This study aimed to investigate the effect of occlusal thickness design on fracture resistance of endocrowns restored with lithium disilicate ceramic and zirconia. METHODS: A total of 24 artificial first mandibular molars were randomly divided into four groups with six teeth in each group as follows: group lithium disilicate ceramic-2 mm (lithium disilicate ceramic, with an occlusal thickness of 2 mm and a retainer length of 4 mm); group lithium disilicate ceramic-4 mm (lithium disilicate ceramic, with an occlusal thickness of 4 mm and a retainer length of 2 mm); group zirconia-2 mm (zirconia, with an occlusal thickness of 2 mm and a retainer length of 4 mm); and group zirconia-4 mm (zirconia, with an occlusal thickness of 4 mm and a retainer length of 2 mm). After adhesive cementation (RelyX Ultimate Clicker), all specimens were subjected to thermocycling (10 000 cycles). The specimens were subjected to fracture resistance testing at a 135° angle to the teeth at a crosshead speed of 0.5 mm·min⁻¹ in a universal testing machine. Data were analyzed with ANOVA and Tukey's HSD test by SPSS 15.0. The failure modes were classified. RESULTS: The fracture resistances of groups lithium disilicate ceramic-2 mm, lithium disilicate ceramic-4 mm, zirconia-2 mm, and zirconia-4 mm were (890.54±83.41), (2 320.87±728.57), (2 258.05±557.66), and (3 847.70±495.99) N respectively. Group zirconia-4 mm had the highest fracture resistance, whereas group lithium disilicate ceramic-2 mm had the lowest. CONCLUSIONS: The fracture resistance of molar endocrown with zirconia is higher than that with lithium disilicate ceramic. Increasing the occlusal thickness can improve the fracture resistance but increase the risk of fracture of abutment.


Asunto(s)
Coronas , Fracaso de la Restauración Dental , Cerámica , Porcelana Dental , Análisis del Estrés Dental , Ensayo de Materiales , Circonio
2.
J Adhes Dent ; 22(5): 531-538, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33073784

RESUMEN

PURPOSE: To evaluate the roughness, surface energy, and the bond strength of lithium disilicate yielded by two different types of nonthermal plasma (NTP), oxygen- or argon-based, compared to the conventional method. MATERIALS AND METHODS: Ninety-three lithium disilicate (IPS e.max Press) samples were divided into 3 groups: HF (hydrofluoric acid group); ONTP (oxygen-based NTP group); ANTP (argon-based NTP group). Surface energy and roughness analyses were performed before and after surface treatment, and bond strength testing was performed before and after 5000 thermocycles. Scanning electron microscopy (SEM) was used to characterize the surface treatments. Data were submitted to ANOVA and Bonferroni's test with statistical significance set at 5%. RESULTS: The ONTP group presented the highest surface energy values, followed by ANTP and HF. In addition, the ONTP group had higher surface roughness. SEM revealed exposed lithium disilicate crystals in the HF group, but a homogeneous film coverage in both NTP groups. Regarding bond strength, ANTP presented statistically significantly higher values than the other groups before thermocycling, and statistically significantly lower values than the other groups after thermocycling. The HF and ONTP groups presented statistically similar values after thermocycling. CONCLUSION: The bond strength of resin cement to lithium disilicate obtained after oxygen-based NTP was comparable with that obtained after conventional hydrofluoric acid treatment.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , Cerámica , Porcelana Dental , Propiedades de Superficie
3.
Shanghai Kou Qiang Yi Xue ; 29(3): 312-315, 2020 Jun.
Artículo en Chino | MEDLINE | ID: mdl-33043351

RESUMEN

PURPOSE: To compare the aesthetic effects of all-ceramic micro-veneer and minimally invasive ultra-thin veneer in repairing deformed anterior teeth. METHODS: One hundred and twenty patients with deformed anterior teeth were selected for aesthetic restoration. According to the patient's personal condition, a suitable repair protocol was selected. Patients in the experimental group (60 cases) were repaired with all-ceramic micro-adhesive surface, while patients in the control group (60 cases) were treated with minimally invasive ultra-thin veneer. The US Public Health Administration's Evaluation Criteria (USPHS) scores were recorded and compared 6 months, 12 months, and 24 months after restoration. Statistical analysis was performed using SPSS 25.0 software package. RESULTS: There was no significant difference in the integrity, color, marginal closeness, translucency and marginal staining of the restorations between the two groups 24 months after operation (P>0.05). The satisfaction rate of the aesthetics of the experimental group was significantly lower than that of the control group (71.60% vs 93.83%, P<0.05). The incidence of complications such as broken, detached and secondary caries during the follow-up period was significantly lower in the experimental group than in the control group (1.23% vs 11.11%, P<0.05). CONCLUSIONS: The results showed that there is no significant difference in the success rate between the two methods. All-ceramic micro-veneer technique has good long-term effect, fewer complications, easy to collapse and stain the lip margin, but it has a small amount of teeth preparation and a low incidence of pulpitis in the later period. Minimally invasive super-thin veneer has high aesthetic value, so it is necessary to choose appropriate aesthetic repair methods according to the patients' needs.


Asunto(s)
Porcelana Dental , Coronas con Frente Estético , Cerámica , Color , Estética Dental , Humanos
4.
Indian J Dent Res ; 31(4): 537-545, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33107453

RESUMEN

Purpose of the Study: To comparatively evaluate the wear resistance of two different posterior indirect restorative materials against human enamel. Materials and Methods: Two different posterior indirect restorative materials of ten in each Group-I (Monolithic zirconia) (n = 10) and Group-II (Cast cobalt chromium) (n = 10) were formed into disc and used as a substrate for the wear test. Freshly extracted mandibular first premolars were used as a pin (antagonist) (n = 20). Pin-on-disc wear testing machine was used to simulate the masticatory parameters and evaluation of the wear parameters was done after 1,20,000 cycles, with load of 40N for specific duration. Data related to wear testing procedure were tabulated and evaluated. Results were statistically analyzed using Mann-Whitney test and Wilcoxon signed rank test. Results: Mean surface roughness value (Ra value) obtained for Group-I disc test samples showed no statistical significance (P value < 0.05). Mean wear rate value of test disc samples was statistically significant between Group-I and Group-II (P value < 0.05). Mean surface roughness value was statistically significant between Groups-I and II before and after wear test (P value < 0.05). Conclusion: From the results obtained, it was found that the Group-I (Monolithic zirconia) exhibited higher wear resistance than Group-II (cast cobalt chromium) and causes less wear to the opposing enamel antagonist.


Asunto(s)
Aleaciones de Cromo , Porcelana Dental , Diseño Asistido por Computadora , Esmalte Dental , Humanos , Ensayo de Materiales , Propiedades de Superficie , Circonio
5.
J Am Dent Assoc ; 151(10): 796-797.e2, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32979959

RESUMEN

BACKGROUND: Bonding crowns and bridges with resin cement can improve retention and reinforcement of the restoration. However, there is variation in the steps taken by different practitioners to achieve this goal. METHODS: The authors developed a survey on bonding dental crowns and bridges with resin cement and distributed it electronically to the American Dental Association Clinical Evaluators (ACE) Panel on May 22, 2020. The survey remained open for 2 weeks. Descriptive data analysis was conducted using SAS Version 9.4. RESULTS: A total of 326 panelists responded to the survey, and 86% of respondents who place crowns or bridges use resin cements for bonding. When placing a lithium disilicate restoration, an almost equal proportion of respondents etch it with hydrofluoric acid in their office or asked the laboratory to do it for them, and more than two-thirds use a silane primer before bonding. For zirconia restorations, 70% reported their restorations are sandblasted in the laboratory, and 39% use a primer containing 10-methacryloyloxydecyl dihydrogen phosphate. One-half of respondents clean their lithium disilicate or zirconia restorations with a cleaning solution. Resin cements used with a primer in the etch-and-rinse mode are the most widely used. The technique used to cure and clean excess resin cement varies among respondents. CONCLUSIONS: The types of resin cements used, tooth preparation, crown or bridge preparation, and bonding technique vary among this sample. PRACTICAL IMPLICATIONS: Although many dentists bond crowns and bridges on the basis of best practices, improvement in the process may be achieved by dentists communicating with their laboratory to confirm the steps performed there, ensuring an effective cleaning technique is used after try-in and verifying that the correct primer is used with their chosen restorative material.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , American Dental Association , Coronas , Cementos Dentales , Materiales Dentales , Porcelana Dental , Análisis del Estrés Dental , Humanos , Ensayo de Materiales , Propiedades de Superficie , Encuestas y Cuestionarios , Estados Unidos
6.
Oper Dent ; 45(6): 664-676, 2020 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-32997740

RESUMEN

CLINICAL RELEVANCE: When a resin nanoceramic inlay is cemented using self-adhesive cement, a universal dentin adhesive can be applied to the prepared cavity. The application of the adhesive before self-adhesive cement placement provides similar or better interfacial adaptation than without the adhesive. SUMMARY: Purpose: The first objective of this study was to determine whether the luting material used for computer-aided design and computer-aided manufacture resin nanoceramic inlays affected interfacial adaptation. The second objective was to investigate whether application of a universal dentin adhesive before cementation affected interfacial adaptation. The final objective was to compare the inlay-side and dentin-side interfaces in the cement space.Methods and Materials: Seventy-four class I cavities were prepared on extracted human third molars. Cavities were optically scanned, and resin nanoceramic inlays were milled using Lava Ultimate blocks (3M ESPE). For the control groups, the fabricated inlays were cemented using Panavia V5 (Kuraray Noritake) or FujiCem 2 (GC). For the experimental groups, the teeth were randomly divided into groups I and II. Group I contained four subgroups using different luting materials; in all subgroups, the inlays were cemented and dual cured without pretreatment. Group II contained six subgroups in which inlays were cemented and dual cured after application of a universal dentin adhesive. After thermocycling, interfacial adaptation was measured using swept-source optical coherence tomography (SS-OCT) imaging and statistically compared among groups.Results: Interfacial adaptation was different depending on the luting material used (p<0.05). After application of a universal adhesive, some subgroups showed improved interfacial adaptation (p<0.05). In the comparison of inlay-side and dentin-side interfaces, no difference was found in interfacial adaptation (p>0.05).Conclusions: Interfacial adaptation for resin nanoceramic inlays differed with luting material. For some self-adhesive cements, application of a universal adhesive before cementation improved interfacial adaptation.


Asunto(s)
Incrustaciones , Tomografía de Coherencia Óptica , Resinas Compuestas , Diseño Asistido por Computadora , Preparación de la Cavidad Dental , Porcelana Dental , Humanos , Ensayo de Materiales , Cementos de Resina
7.
J Esthet Restor Dent ; 32(7): 726-733, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32886852

RESUMEN

OBJECTIVE: To evaluate the microtensile bond strength of four dental computer-aided design/computer-aided manufactured (CAD/CAM) ceramics after application of four different surface treatments. MATERIALS AND METHODS: Four dental CAD/CAM ceramics were tested: feldspathic ceramic (VITABLOCKS-Mark II), polymer-infiltrated ceramic network (VITA ENAMIC), zirconia-reinforced lithium silicate (VITA SUPRINITY), and yttria-stabilized zirconia (VITA YZ T). Four surface treatments were applied: no treatment, 5% hydrofluoric acid-etching, airborne particle abrasion, and tribochemical silica coating. The ceramic blocks were repaired with nanohybrid composite (Tetric N-Collection). Sixteen test groups of 12 specimens were prepared. After thermocycling, microtensile bond testing was performed. The microtensile strengths values were statistically analyzed using two-way analysis of variance and Tukey's post-hoc test. RESULTS: Repaired feldspathic and resin polymer-infiltrated ceramic network ceramics demonstrated superior microtensile bond strengths compared to zirconia-reinforced lithium silicate and yttria-stabilized zirconia. Etched feldspathic and polymer-infiltrated ceramic network ceramics had higher bond strength than the untreated groups. Surface treatments did not affect the bond strength of zirconia-reinforced lithium silicate and yttria-stabilized zirconia with the exception of etching, which reduced the bond strength of yttria-stabilized zirconia. CONCLUSION: Feldspathic ceramic and polymer-infiltrated ceramic network were repaired with dental composite after surface etching with hydrofluoric acid. Repair of zirconia-reinforced lithium silicate and yttria-stabilized zirconia did not demonstrate promising results. CLINICAL SIGNIFICANCE: Repair of feldspathic ceramic and polymer-infiltrated ceramic network restorations may be a cost-effective means to promote the longevity of dental restorations. However, zirconia and zirconia-reinforced lithium disilicate restorations do not offer such an option.


Asunto(s)
Recubrimiento Dental Adhesivo , Cerámica , Diseño Asistido por Computadora , Porcelana Dental , Análisis del Estrés Dental , Ensayo de Materiales , Cementos de Resina , Propiedades de Superficie , Circonio
8.
Int J Prosthodont ; 33(5): 536-545, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32956435

RESUMEN

PURPOSE: To evaluate the shear bond strength (SBS) and color stability (ΔE) of four ceramic veneers (VITA VM 9; VITA VM 13; VITA VMK 95; and IPS e.max Ceram) following repair with three different self-adhesive composite resins (Fusio Liquid Dentin; Constic; and Vertise Flow) and BISCO Intraoral Repair Kit + Filtek Supreme (BC + FS). MATERIALS AND METHODS: A total of 96 specimens were prepared per ceramic material, and each ceramic group was divided into subgroups according to testing method (32 specimens for color stability analysis and 64 specimens for SBS testing). ΔE and SBS (SBS1 = non-aged, SBS2 = thermally aged) values of the repaired specimens were calculated. One specimen from each of the thermally aged groups was investigated under scanning electron microscopy (SEM). Two-way ANOVA was used to analyze the mean ΔE, SBS1, and SBS2 values. The differences between SBS1 and SBS2 values were analyzed using independent-samples t test. RESULTS: The lowest ΔE values were calculated for Constic (P ≤ .05). The SBS2 values among all groups were lower than the SBS1 values (P ≤ .05). The lowest SBS2 values were observed for Vertise Flow (2.3 ± 1.47 MPa) (P ≤ .05) and were below the acceptable limit of 5 MPa. CONCLUSION: All of the investigated repair materials in combination with the ceramic veneers exhibited ΔE values that were higher than the clinically acceptable limits. Thermal aging negatively affected the SBS values in all groups (P ≤ .05). All tested self-adhesive composite resins, with the exception of Vertise Flow, could be used instead of a repair kit with flowable composite resin, especially in noncooperative patients, for the purpose of repairing chipping fractures for VITA VM 9, VITA VM 13, and VITA VMK 95 (P > .05).


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos Dentales , Resinas Acrílicas , Cerámica , Color , Resinas Compuestas , Porcelana Dental , Humanos , Ensayo de Materiales , Cementos de Resina , Resistencia al Corte , Propiedades de Superficie
9.
Chin J Dent Res ; 23(3): 183-189, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32974618

RESUMEN

OBJECTIVE: To design and fabricate 3D-printed rigid constraint guides for the tooth preparation for laminate veneers and to evaluate the accuracy of guide-assisted preparation. METHODS: Twenty maxillary right central incisor resin artificial teeth were randomly divided into two equal groups and prepared for laminate veneers. Tooth preparations were performed, assisted by guides in the test group and by depth gauge burs in the control group, and both were finished by freehand operation. The typodonts were 3D scanned before preparation, after initial preparation and after final preparation. The tooth preparation depths at each step, including initial preparation depth, final preparation depth and loss of tooth tissue during polishing, were measured by 3D deviation analysis. Statistical analyses were conducted to investigate differences. RESULTS: The initial preparation depth was 0.488 mm (median, quartile 0.013 mm) in the test group and 0.521 mm (median, quartile 0.013 mm) in the control group. A statistically significant difference was found between them (P < 0.05). The final preparation depth in the test group (0.547 ± 0.029 mm) was significantly less than that in the control group (0.599 ± 0.051 mm) (P < 0.05), and closer to the predesigned value (0.5 mm). There was no statistically significant difference in the loss of tooth tissue during polishing between the test group (0.072 ± 0.023 mm) and the control group (0.089 ± 0.038 mm) (P > 0.05). CONCLUSION: In maxillary central incisors, the tooth preparation for laminate veneers could be conducted using 3D-printed rigid constraint guides, the accuracy of which is better than that of depth gauge burs.


Asunto(s)
Porcelana Dental , Coronas con Frente Estético , Incisivo , Rayos Láser , Preparación del Diente
10.
J Oral Sci ; 62(4): 430-434, 2020 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-32863318

RESUMEN

Perception of tooth shades is subjective and not rated exactly the same by different individuals. In terms of dental esthetics, chairside individualization of dental restorations might help to improve patient satisfaction. This investigation aimed to validate the practicability of a chairside approach for staining resin-based composite restorations. Thirteen inexperienced and 13 experienced participants were recruited to first individualize two CAD/CAM resin-based composite crowns in randomized order with light-curing characterization material using two reference crowns as templates. They then evaluated the characterization procedure. The processing times were recorded, and the clinical quality of the individualized crowns was evaluated by two blinded master dental technicians. Of the 52 crowns examined, 90.4% were assessed as suitable for insertion; there was no difference in quality attributable to the different degrees of experience of the operators. The average time required for characterization of the second crown was significantly shorter than for the first crown (30.9/43.0 min), indicating that the procedure can be implemented using a chairside approach. Among the operators, 80.8% said they would use the individualization technique and staining material again. Chairside staining of CAD/CAM resin-based composite restorations with light-curing characterization materials is practicable and can be recommended for both experienced and inexperienced users.


Asunto(s)
Porcelana Dental , Diseño de Prótesis Dental , Cerámica , Resinas Compuestas , Diseño Asistido por Computadora , Coronas , Materiales Dentales , Humanos
12.
Acta Odontol Latinoam ; 33(2): 98, 2020 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-32920611

RESUMEN

The aim of the current study was to compare the effect of two lithium disilicate ceramic processing techniques (pressing and CAD/CAM) on the degree of conversion of resin cement when it is photoactivated and the microshear bond strength of resin cement to ceramics. Two ceramic discs were manufactured: one by the Press technique and another by CAD/CAM technique. Five Variolink Veneer resin cement samples were photoactivated through each ceramic disc and subjected to attenuated total reflectance Fourier transform infrared spectroscopy to evaluate their degree of conversion. To evaluate microshear bond strength, 20 ceramic bars were prepared: 10 using the Press technique and 10 using the CAD/CAM technique. The bars were air abraded with 50-µm Al2O3 particles, treated with 10% hydrofluoric acid for 20 s and subjected to RelyX Ceramic Primer application. Adper Scotchbond Multi-Purpose Adhesive was applied to the bars and cured for 10 s. Two 1-mm-height plastic tubes were placed on each bar and filled with Variolink Veneer resin cement. Each cylinder was cured for 20 s. Then the plastic tubes were removed and the microshear bond strength of each cylinder was tested. Data for degree of conversion (%) and microshear bond strength (MPa) were subjected to Student's t-test (α = 0.05). Both degree of conversion of resin cement photoactivated through ceramic and microshear bond strength of resin cement to ceramic were statistically higher in the group in which ceramic was prepared by CAD/CAM technique (44.74% and 22.18 MPa) than in the group in which the ceramic was prepared by the Press technique (25.71% and 19.83 MPa). The lithium disilicate ceramic processing techniques affected the degree of conversion of resin cement when it is photoactivated through the ceramics and the microshear bond strength of resin cement to ceramics.


Asunto(s)
Cerámica/química , Recubrimiento Dental Adhesivo , Porcelana Dental/química , Cementos de Resina/química , Humanos , Ensayo de Materiales , Propiedades de Superficie
13.
J Esthet Restor Dent ; 32(7): 645-661, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32776711

RESUMEN

OBJECTIVES: To introduce a minimally invasive and simple ortho-pros approach for localized tooth wear treatment. CLINICAL CONSIDERATIONS: Four patients with localized anterior and/or posterior tooth wear were treated. Occlusal analyses were performed, and localized wax-up or digital setup were designed based on estimated tissue loss. No-prep anterior and posterior partial-coverage polymer-infiltrated ceramic network (PICN, Vita Enamic) restorations (eg, palatal and occlusal veneers) were computer-aided designed and manufactured (CAD-CAM), tried in, and bonded in supraocclusion, creating a posterior open bite. Then, brief partial (three patients) or global (one patient, for anterior teeth alignment request) orthodontic treatment was performed to extrude the posterior teeth and re-establish posterior occlusal contacts. The orthodontic treatment duration was ~2 months for extrusion. Direct composites were performed to mask the labial finish line of palatal veneers. Clinical results were successful after a follow-up of 15, 21, 23, and 47 months, with 100% success rate of PICN anterior restorations and some minor chippings of borders of thin (0.2 mm) posterior occlusal veneers. Patient-reported outcomes were positive. CONCLUSION: Orthodontic-assisted one step-no prep technique is an advantageous and straightforward evolution of the Dahl concept. PICNs exhibit several advantages in this interdisciplinary approach. CLINICAL SIGNIFICANCE: New hybrid-ceramic CAD-CAM materials and a collaborative interdisciplinary approach support the evolution of the Dahl concept for conservative treatment of worn dentitions. The orthodontic-assisted one step-no prep technique is predictable, efficient, and well tolerated by patients and conserves tooth structure.


Asunto(s)
Implantes Dentales , Desgaste de los Dientes , Cerámica , Diseño Asistido por Computadora , Porcelana Dental , Humanos , Polímeros
14.
J Prosthodont ; 29(8): 693-698, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32767417

RESUMEN

PURPOSE: This study was done to compare the survival rates of cast gold and ceramic onlays placed in a dental school setting. MATERIAL AND METHODS: An electronic search was conducted in the patient records at Adams School of Dentistry, University of North Carolina at Chapel Hill for onlay codes that were in the database (From 1998 until 2018). Progress notes and radiographs were scrutinized to establish the survival time of the restorations. Any complications that occurred during the life time of the restorations were noted. The survival was summarized by categorization based on ranges of survival time in years; group 1: 1 to 5 years, group 2: 6 to 22 years. The mean survival time and standard deviation were calculated. One-way ANOVA was used to determine whether there was a statistically significant difference in the survival times between gold and ceramic onlays. RESULTS: The mean survival rate of cast gold onlays (86.6%) was comparable to that of ceramic onlays (81.1%). The gold onlays in Group 1 had a higher mean survival time (2.43 years) than the ceramic onlays (2.03 years). This difference was statistically significant (p = 0.002). The ceramic onlays in Group 2 had a mean survival time of 19.75 years while gold onlays had a mean survival time of 17.63 years. This difference was not statistically significant (p = 0.91). CONCLUSION: It was concluded that while the survival rate of ceramic onlays (81.1%) was inferior to that of cast gold onlays (86.6%), it was comparable.


Asunto(s)
Oro , Incrustaciones , Cerámica , Porcelana Dental , Fracaso de la Restauración Dental , Humanos , Estudios Retrospectivos
15.
J Oral Sci ; 62(4): 353-355, 2020 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-32741852

RESUMEN

Computer-aided design/computer-aided manufacturing (CAD/CAM) restorative materials have been widely used owing to a number of advantages, including stable quality of the materials, lower costs, and time-saving factors. Resin-based CAD/CAM materials for definitive restorations are classified into two groups: dispersed nanoparticle-filled composite resin and polymer-infiltrated-ceramic-network materials. Resin-based CAD/CAM materials have been applied to single crown restorations as a monolithic structure for the posterior region. In addition, resin-based CAD/CAM restorations have been applied recently for the anterior area. This literature review summarizes clinical outcomes, such as survival rates and clinical complications of single crown restorations fabricated with resin-based CAD/CAM materials.


Asunto(s)
Diseño Asistido por Computadora , Coronas , Cerámica , Resinas Compuestas , Materiales Dentales , Porcelana Dental , Diseño de Prótesis Dental , Ensayo de Materiales
16.
Indian J Dent Res ; 31(3): 470-474, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32769285

RESUMEN

Objectives: To evaluate the leachable components of resin cements in oral simulating fluids using high performance liquid chromatography and its resultant shear bond strength with ceramics. Methods: Forty extracted permanent human mandibular molar teeth were sectioned horizontally with a disc beneath the dentino-enamel junction to expose the coronal dentin surface and later finished with 600-grit silicon carbide paper to create a uniform flat surface. Forty Lithium Di-silicate Ceramic block cylinders were sliced in a saw cutting machine at 250 rpm under water-cooling to obtain the discs. The teeth and the ceramic discs were then randomly assigned to two groups on the basis of material used for luting the ceramic disk. Group I: Ceramic disc luted with tooth surface using Variolink II Dual cure Resin Cement, Group II: Ceramic disc luted with tooth surface using multilink speed self-adhesive self-curing resin cement. All ceramic discs were etched with 5% HF acid (IPS Ceramic Etching Gel, Ivoclar, Schaan, Liechtenstein) for 20 seconds, then rinsed thoroughly for 20 seconds and dried for 20 seconds. Ceramic specimens were luted on dentin surfaces with the application of 5 kg load. The samples were stored in 75% ethanol solution for 2 weeks at 37 degree Celsius for chemical aging. HPLC Analysis were performed to analyze the eluted monomer. After HPLC Analysis, Samples were then loaded using universal testing machine for the evaluation of shear bond strength between ceramic discs and the resin cements before and after the elution of monomers. Results: Under HPLC analysis, results showed that the peak release of monomer is Bis-GMA in both the groups. The shear force required to break the bond between the ceramic luted to tooth surface with the resin cements were more for Group I. Statistical results: The statistical analysis was done using ANOVA and paired t-test and it shows P value ≥0.05, hence the null hypothesis is rejected. Conclusion: The monomer eluded from all the groups are identified as Bis-GMA, The eluded monomer decreases the bond strength between the resin cement and the ceramic due to water sorption, The Variolink II (dual cure) resin cement shows improved bond strength than the Multilink (self-cure self-adhesive) resin cement.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , Cerámica , Cementos Dentales , Porcelana Dental , Análisis del Estrés Dental , Humanos , Ensayo de Materiales , Resistencia al Corte , Propiedades de Superficie
17.
Int J Comput Dent ; 23(3): 225-233, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32789310

RESUMEN

AIM: To evaluate the fracture resistance and failure pattern of 3D-printed and milled composite resin crowns as a function of different material thicknesses. MATERIALS AND METHODS: Three typodont tooth models were prepared to receive a full coverage composite resin crown with different thicknesses (0.5, 1.0, and 1.5 mm). The prepared master casts were digitally scanned using an intraoral scanner, and the STL files were used to fabricate 60 nanocomposite crowns divided into two groups according to the material thickness (n = 10) and fabrication method: a 3D-printed group (3D) using an SLA printer with nanocomposite, and a milled group (M) using a milling machine and composite blocks. All crowns were adhesively seated on stereolithography (SLA)-fabricated dies. All samples were subjected to thermomechanical loading and fracture testing. The load to fracture [N] was recorded and the failure pattern evaluated. Data were statistically analyzed using a two-way ANOVA followed by a Bonferroni post hoc test. The level of significance was set at α = 0.05. RESULTS: The 3D group showed the highest values for fracture resistance compared with the milled group within the three tested thicknesses (P < 0.001). The 3D and M groups presented significantly higher load to fracture for the 1.5-mm thickness (2383.5 ± 188.58 N and 1284.7 ± 77.62 N, respectively) compared with the 1.0-mm thickness (1945.9 ± 65.32 N and 932.1 ± 41.29 N, respectively) and the 0.5-mm thickness, which showed the lowest values in both groups (1345.0 ± 101.15 N and 519.3 ± 32.96 N, respectively). A higher incidence of irreparable fractures was observed for the 1.5-mm thickness. CONCLUSION: 3D-printed composite resin crowns showed high fracture resistance at different material thicknesses and can be suggested as a viable solution in conservative dentistry.


Asunto(s)
Porcelana Dental , Fracaso de la Restauración Dental , Cerámica , Diseño Asistido por Computadora , Coronas , Diseño de Prótesis Dental , Análisis del Estrés Dental , Humanos , Ensayo de Materiales , Impresión Tridimensional
19.
Dent Med Probl ; 57(2): 197-206, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32673449

RESUMEN

The use of ceramic materials and the computer-aided design/computer-aided manufacturing (CAD/CAM) technology for the fabrication of complete-coverage restorations has significantly increased in the last decade. The aim of this study was to evaluate the survival rate of anterior and posterior monolithic and bilayered lithium disilicate glass-ceramic (LDGC) CAD/CAM crowns, and to identify the types of complications associated with the main clinical outcomes reported in clinical trials. MEDLINE/PubMed, Embase, Scopus, Web of Science, Cochrane Library, and ClinicalTrials.gov were searched by 2 independent reviewers for clinical studies published between 2006 and 2019, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The electronic search was supplemented by a hand search. Quality assessment for the included studies was performed. Qualitative and quantitative data was extracted from each study. Out of 219 studies, 6 studies that evaluated LDGC CAD/CAM crowns were identified and used for data extraction. The included studies had 154 participants, who received 204 crowns. The shortto medium-term survival and success rates were high. Biological complications occurred more frequently than technical complications. No esthetic complications were reported. This review indicated that the medium-term survival rate of LDGC CAD/CAM crowns was high. Further multicenter studies with longer follow-ups and larger sample sizes are needed in order to augment the data already in existence.


Asunto(s)
Diseño de Prótesis Dental , Estética Dental , Cerámica , Diseño Asistido por Computadora , Coronas , Porcelana Dental , Humanos
20.
Dent Med Probl ; 57(2): 185-190, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32609957

RESUMEN

BACKGROUND: Marginal fit is the most important criterion in the evaluation of the clinical acceptability of fixed restorations. Due to cement solubility and plaque retention, marginal gaps are potentially harmful to both the teeth and the periodontal tissues. OBJECTIVES: The aim of the study was to investigate the accuracy of the fit of dental metal-ceramic bridges manufactured with the use of direct metal laser sintering (DMLS), and to explore the effects of porcelain firing on the marginal, axial and occlusal fit of metal-ceramic frameworks. MATERIAL AND METHODS: The study involved 10 patients with 3-unit metal-ceramic restorations produced using the DMLS technique. Using the silicone replica technique, we examined the marginal, axial and occlusal fit of the dental bridges before and after ceramic firing. The Shapiro-Wilks normality test and Student's paired t­test were implemented to analyze the mean differences in the marginal, axial and occlusal fit of the restorations before and after ceramic firing. A 95% confidence interval (CI) and discrepancy values at the level of 1% and 0.1% (p > 0.05) were applied. RESULTS: All the mean values of the measurements of marginal (156.08 µm), axial (95.75 µm) and occlusal (252.83 µm) gaps were lower before ceramic veneering than after ceramic veneering, when the mean value for the marginal gap was 178.17 µm, for the axial gap - 106.75 µm and for the occlusal gap - 266.00 µm. CONCLUSIONS: Porcelain firing caused no statistically significant differences in the discrepancy values of marginal, axial and occlusal fit. For clinical application, further improvement of the DMLS system is highly recommended. Marginal gaps in DLSM bridges significantly exceed the permissible inaccuracy values of 100-120 µm for prosthetic restorations.


Asunto(s)
Adaptación Marginal Dental , Porcelana Dental , Cerámica , Diseño Asistido por Computadora , Diseño de Prótesis Dental , Humanos
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