Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 461
Filtrar
1.
Dent Mater J ; 2021 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-33642447

RESUMEN

This study aimed to evaluate polylactic acid (PLA) as a provisional crown material. Lower right first molar phantom tooth was used for the fabrication of 60 crowns. Samples were divided into three groups (n=20) according to the material: Group PL (PLA), Group PM (polymethyl methacrylate), and Group PE (polyetheretherketone). Each group was investigated for internal and marginal fit, fracture strength, and fracture mode. Data were analyzed using ANOVA, chi-squared test, and Tukey's tests (p≤0.05). The average marginal gap value of each group was: PE 56.00±4.67 µm, PM 61.15±4.44 µm, and PL 60.40±2.85 µm (p<0.001). The average internal gap value for each group was: PE 128.90±8.39 µm, PM 132.40±7.51 µm, and PL 130.75±9.76 µm (p=0.442). The average fracture strength of each group was: PE 840.90±13.23 N, PM 733.30±9.00 N, and PL 664.50±10.79 N (p<0.001). Results demonstrated that PLA may be a good option as a provisional crown material.

2.
J Prosthet Dent ; 2021 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-33573835

RESUMEN

STATEMENT OF PROBLEM: Which surface treatment provides the optimal bond strength (BS) for the repair of resin nanoceramics (RNCs) and polymer-infiltrated ceramics (PICs) is unclear. PURPOSE: The purpose of this systematic review and meta-analysis of in vitro studies was to determine the best surface treatment protocols for the repair of PICs and RNCs. MATERIAL AND METHODS: The PubMed, Scopus, and Web of Science electronic databases were searched to select in vitro studies in English up to March 2020. Studies with fewer than 5 specimens, those that did not evaluate the BS of PICs or RNCs, and those with aging for fewer than 30 days and 5000 cycles were excluded. Data sets were extracted, and the mean differences were analyzed by using a systematic review software program. RESULTS: Among 284 potentially eligible studies, 21 were selected for full-text analysis, and 9 were included in the systematic review, of which 6 were used in the meta-analysis. The meta-analyses were performed for each treatment surface versus their respective control group and their combinations according to material: RNCs and PICs. For RNCs, airborne-particle abrasion with aluminum oxide (Al2O3) treatment was statistically higher than tribochemical silica airborne-particle abrasion (CoJet) (P=.02, I2=90%) and that in the hydrofluoric acid (HF) (P<.001, I2=0%) groups and was statistically similar to diamond rotary instrument grinding (P=.40, I2=54%). For PICs, the treatment with hydrofluoric acid (HF) was statistically significantly higher than with CoJet (P=.03, I2=62%) and airborne-particle abrasion with Al2O3 (P<.001, I2=98%). CONCLUSIONS: The best surface treatment protocol for repair varied according to the restorative material. HF followed by silanization is suggested for PICs, and airborne-particle abrasion with Al2O3 or preparation with a diamond rotary instrument for RNCs.

3.
J Dent ; : 103611, 2021 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-33617944

RESUMEN

OBJECTIVES: The objective of this retrospective practice-based study was to evaluate the survival of molar teeth and endodontic success after complex endodontic treatment up to 89 months. METHODS: Endodontically (Endodontic Treatment Classification (ETC) scores II and III) treated first and second molars treated between January 2011-October 2017 within a referral setting were included. Open apices, combined surgical treatment, ETC score I, patients <18 years or with an ASA-score >2 were excluded. Cumulative survival estimates and Cox regression analysis were performed for tooth survival and endodontic healing according to the Glossary of Endodontic Terms. Restoration quality was assessed using the FDI criteria. Alpha was set at 0.05. RESULTS: 279 endodontically treated molars in 245 patients were included for survival analysis and 268 molars for endodontic success. After 89 months, the cumulative survival was 91.7% [95% CI: 86.8%-94.9%]. Absence of adjacent teeth and deviance in root canal morphology significantly decreased the probability of tooth survival. Cumulative endododontic healing rates after 48 and 89 months were 82.2% [95%CI: 75.7%-87.1%] and 51.1 [95% CI: 20.2%-75.5%] respectively. Deviance in root canal morphology and inadequate coronal seal significantly decreased the probability of endodontic healing. Indirect restorations obtained higher esthetic and biological FDI scores, however no difference between direct and indirect restorations was found concerning the functional FDI score. CONCLUSIONS: After 89 months, cumulative survival of molars in need of complex endodontic treatment was 91.7% [95% CI: 86.8%-94.9%]. CLINICAL SIGNIFICANCE: Within daily clinical practice, the dilemma of performing a complex endodontic (re)treatment or to explore other treatment options for molar teeth in need of reintervention is still urgent. Tooth survival of molar teeth with complex endodontic (re)treatment seems satisfactory up to 89 months.

4.
J Prosthet Dent ; 2021 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-33546860

RESUMEN

STATEMENT OF PROBLEM: Studies investigating the mechanical stability of lithium disilicate-strengthened aluminosilicate glass ceramic that do not require sintering after milling compared with other computer-aided design and computer-aided manufacturing (CAD-CAM) materials are lacking. PURPOSE: The purpose of this in vitro study was to investigate the flexural strength of CAD-CAM zirconia, lithium disilicate, and lithium disilicate-strengthened aluminosilicate glass ceramics with and without fatigue conditions. MATERIAL AND METHODS: Specimens (N=90, n=15) (12×4×3 mm) from the following CAD-CAM materials were prepared and polished: lithium disilicate glass ceramic (IPS e.max CAD); lithium disilicate-strengthened aluminosilicate glass ceramic (N!ce); and zirconium dioxide ceramic (IPS e.max ZirCAD). All specimens were divided into 2 subgroups: immediate testing without aging and simulation of aging by using a mastication simulator for 1 200 000 cycles (5 °C-55 °C). Thereafter, flexural strength testing was performed by using a universal testing machine (1 mm/min) on nonaged and aged specimens. The data were evaluated by using nonparametric 2-way ANOVA and Wilcoxon rank post hoc tests (α=.05). RESULTS: Both the material type and aging significantly affected the results (P<.001). The interaction was not significant (P>.05). Under nonaged conditions, zirconium dioxide ceramic (1136 ±162 MPa) showed significantly higher mean ±standard deviation flexural strength (P<.001) than lithium disilicate (304 ±34 MPa) and lithium disilicate-strengthened aluminosilicate glass ceramic (202 ±17 MPa). The glass ceramic groups were also significantly different from each other (P<.001). After aging, zirconium dioxide (1087.9 ±185.3 MPa) also presented significantly higher mean ±standard deviation flexural strength (P<.001) than lithium disilicate (259 ±62 MPa) and lithium disilicate-strengthened aluminosilicate glass ceramic (172 ±11 MPa) (P<.001). Aging significantly decreased the flexural strength of lithium disilicate (14.6%) (P=.03) and lithium disilicate-strengthened aluminosilicate glass ceramic (14.5%) (P=.01) but had minimal effect on the zirconium dioxide ceramic (4.3%) (P=.29). CONCLUSIONS: Among the tested CAD-CAM materials, the mechanical performance of lithium disilicate-strengthened aluminosilicate glass ceramic was comparable with that of lithium disilicate and considerably lower than that of zirconia. Aging decreased the flexural strength of both lithium disilicate and lithium disilicate-strengthened aluminosilicate glass ceramic.

7.
Mater Sci Eng C Mater Biol Appl ; 121: 111849, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33579483

RESUMEN

The fabrication of 3D fibrous scaffolds with highly interconnected pores has been crucial in the development of tissue regeneration techniques. The present study describes the fabrication of 3D fibrous scaffolds by freeze-drying of polydopamine (PDA) coated centrifugal spun gelatin fibers. We wanted to combine the mussel-inspired chemistry, Maillard reaction, and the 3D microstructural advantages of centrifugal spun fibers to develop the green fibrous scaffolds at low cost, high speed, and desired mold shape. The resultant PDA-gelatin fibers exhibited a smooth 3D microstructure with a uniform formation of PDA thin ad-layer that enhanced the mechanical properties and stability of the scaffolds, and thereby decreased the degradation rate. All scaffolds showed promising properties including good dimensional and mechanical stability under wet state, optimal porosity over 94%, and high water uptake of approximately 1500%. The results of cell culture studies, further confirmed that all scaffolds exhibited appropriate biocompatibility, cell proliferation, migration, and infiltration. Particularly, the PDA-coated scaffolds showed a significant enhancement in proliferation, migration, and infiltration of HDF-GFP+ cells. These results show that a 3D porous fibrous scaffold with simplifying tunable density and desirable shape on a large scale can be readily prepared for different fields of tissue engineering applications.

8.
Int J Prosthodont ; 34(1): 79-87, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33570523

RESUMEN

PURPOSE: To measure the effect of simulated aging on stained resin-ceramic CAD/CAM materials regarding the durability of color and gloss. MATERIALS AND METHODS: Test specimens (n = 15 per material) were prepared out of CAD/CAM ingots from two resin nanoceramics (Lava Ultimate [LVU], Cerasmart [CER]) and a polymer-infiltrated ceramic (ENA, VITA Enamic) stained with the manufacturer's recommended staining kit using photopolymerization. Control specimens were made of feldspathic ceramic (VITA Mark II [VM2]) and stained by means of ceramic firing. Negative control specimens (n = 15) (no staining) were prepared for each group. Color and gloss measurements were performed before and after each aging cycle by means of mechanical abrasion with a toothbrush. Groups were compared using Kruskal-Wallis test and paired post hoc Conover test. Changes within a group were calculated using Wilcoxon signed-rank test (α = .05). RESULTS: The color difference (ΔE) was statistically significant for all stained CAD/CAM materials after simulated aging: CER (P < .001, 95% CI: 2.96 to 3.69), LVU (P = .004, 95% CI: 1.09 to 1.46), ENA (P = .004, 95% CI: 0.20 to 0.42), and VM2 (P < .001, 95% CI: 0.29 to 1.08). Aging resulted in a statistically significant increase in gloss in the LVU group (P < 0.001, 95% CI: 13.78 to 17.29), whereas in the ENA (P < .001, 95% CI: 7.83 to 12.72), CER (P < .001, 95% CI: 2.69 to 8.44), and VM2 (P = .014, 95% CI: 0.22 to 1.87) groups, a significant decrease in gloss was noted. CONCLUSION: Color and gloss of stained resin-ceramic CAD/CAM materials changed significantly after aging by means of toothbrush abrasion in vitro.


Asunto(s)
Cerámica , Diseño Asistido por Computadora , Color , Resinas Compuestas , Porcelana Dental , Ensayo de Materiales , Propiedades de Superficie
9.
Dent Mater ; 2021 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-33589269

RESUMEN

OBJECTIVE: The objective of this study was to evaluate the combined effect of the sulfuric acid etching and an acidic adhesive conditioning on the shear bond strength of PEEK to a resin-matrix composite. MATERIALS AND METHODS: Forty PEEK specimens were assigned randomly to 4 groups for H2SO4 etching followed by universal adhesive (pH at 2.5) conditioning for 0, 1, 3, and 5 min. Thirty PEEK specimens were divided into 3 groups for only acidic adhesive conditioning for 0, 1, 3, and 5 min. After the light-curing of the adhesive, a nanohybrid resin composite was applied onto the surfaces and then light-cured following the manufacturer`s guidelines. All specimens were stored in distilled water at 37 °C for 24 h mechanical testing. Shear bond strength tests were performed using a universal testing machine. Surfaces were analyzed by SEM, light interferometry, FTIR, and liquid contact angle measurement. Statistical analysis was performed by one-way ANOVA and Tukey's post hoc tests (p < 0.05). RESULTS: No adhesion was achieved between untreated PEEK a resin-matrix composite, regardless of the adhesive conditioning time points. Shear bond strength of H2SO4-etched PEEK to resin-matrix composite increased with time (0 mmin. 4.95 ± 2.86 MPa < 1 min: 9.35 ± 2.26 MPa < 3 min: 17.84 ± 2.82 MPa < 5 min: 21.43 ± 5.00 MPa). SEM images revealed a significant modification of PEEK surface topography after the H2SO4 etching. SIGNIFICANCE: The acidic adhesive was unable to modify the untreated PEEK surface to establish an effective adhesion although a synergistic effect was noticed when the universal (acidic) adhesive was applied over a H2SO4-etched PEEK surface, thus improving the PEEK to resin-matrix composite adhesion.

10.
J Prosthodont ; 2021 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-33415779

RESUMEN

PURPOSE: An in vitro study to compare the adaptation of denture bases fabricated with 4 different techniques using volumetric 3-dimentional (3D) analysis. MATERIAL AND METHODS: Edentulous maxillary and mandibular casts were scanned, and standardized denture bases were designed using CAD design software. The same standard tessellation language (STL) data were used to produce the denture bases with 4 different fabrication methods: compression molding (CM), injection molding (IM), PMMA milling (PM), and 3D printing (3D) (n = 11/group). Milled wax denture bases were used to fabricate CM and IM groups. Denture bases placed on edentulous casts were scanned using micro-computed tomography (micro-CT). Volumetric gap between denture base and cast was calculated from 6 locations for maxilla (anterior ridge crest, posterior ridge crest, labial vestibule, buccal vestibule, palate, and posterior palatal seal) and 3 locations for mandible (intermolar, molar, and retromolar) in addition to overall gap measurements for edentulous arches. The data were analyzed with factorial analysis of variance (ANOVA), 1-way ANOVA, and post-hoc Duncan tests. Reproducibility of fabrication methods with regard to each location was assessed using Z test (α = 0.05). RESULTS: In the maxilla, the highest and lowest palatal gap measurements were recorded for CM (898.44 ± 87.73 mm3 ) and PM (357.16 ± 57.68 mm3 ) (p = 0.05). The highest gap measurements for CM and 3D were at palate and, for IM and PM were at posterior ridge crest. In mandible, the volumetric gap measurements for CM were the highest and for PM were the lowest irrespective of location (p = 0.05). PM group showed the best reproducibility and adaptation with the lowest overall mean gaps for both edentulous arches (p = 0.05). CONCLUSIONS: Denture bases milled from PMMA blocks showed better adaptation than 3D printed, or wax milled and conventionally fabricated denture bases for both maxillary and mandibular arches. PMMA milling is a reproducible technique that enables the construction of accurate dentures. Clinicians should be cautious about the palatal gap when the compression molding technique is used. Micro-CT is a valid technique for evaluating the denture base adaptation.

11.
BMC Oral Health ; 21(1): 37, 2021 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-33478459

RESUMEN

BACKGROUND: The purpose of this narrative review was to examine the applicability of IOS procedures regarding single and multiple fixed implant restorations. Clinical outcomes for monolithic zirconia and lithium disilicate restorations produced through a direct digital workflow were reported. METHODS: A MEDLINE (Pubmed) search of the relevant English-language literature spanning from January 1st 2015 until March 31st 2020 was conducted. In vitro studies comparing digital implant impression accuracy by different IOS devices or in vitro studies examining differences in accuracy between digital and conventional impression procedures were included. Also, RCTs, clinical trials and case series on the success and/or survival of monolithic zirconia and lithium disilicate restorations on implants, manufactured completely digitally were included. In vitro and in vivo studies reporting on restorations produced through an indirect digital workflow, case reports and non-English language articles were excluded. The aim was to investigate the accuracy of IOS for single and multiple fixed implant restorations compared to the conventional impression methods and report on the variables that influence it. Finally, this study aimed to report on the survival and success of fixed implant-retained restorations fabricated using the direct digital workflow. RESULTS: For the single and short-span implant sites, IOS accuracy was high and the deviations in the position of the virtual implant fell within the acceptable clinical limits. In the complete edentulous arch with multiple implants, no consensus regarding the superiority of the conventional, splinted, custom tray impression procedure compared to the IOS impression was identified. Moreover, complete-arch IOS impressions were more accurate than conventional, non-splinted, open or close tray impressions. Factors related to scanbody design as well as scanner generation, scanning range and interimplant distance were found to influence complete-arch scanning accuracy. Single implant-retained monolithic restorations exhibited high success and survival rates and minor complications for short to medium follow-up periods. CONCLUSIONS: The vast majority of identified studies were in vitro and this limited their clinical significance. Nevertheless, intraoral scanning exhibited high accuracy both for single and multiple implant restorations. Available literature on single-implant monolithic restorations manufactured through a complete digital workflow shows promising results for a follow-up of 3-5 years.

12.
Braz. dent. sci ; 24(1): 1-9, 2021. tab
Artículo en Inglés | LILACS, BBO - Odontología | ID: biblio-1145369

RESUMEN

Objective: The aim of the study was to assessment of technical quality of 9562 endodontic cases treated by heterogeneous groups with different clinical experience. Material and methods: This retrospective study reviewed the dental records of 8590 patients (9562 endodontic cases and 13203 root canals including 3340 retreatment root canals) treated by fourth-year undergraduates, fifth-year undergraduates, endodontic program students, and endodontic specialists between December 2017 and December 2018 at the Department of Endodontics of Necmettin Erbakan University Faculty of Dentistry in Konya. The length, density, and taper of root fillings, the acceptable technical quality of the root filling criteria, and the presence of procedural errors, were recorded. Chi-square tests with a significance level at p=0.05 were used for statistical analysis. Results: Acceptable root fillings were found in 71.5% of endodontic cases. Clinical experience showed statistical differences in the root filling quality among fourth-year undergraduates, fifth-year undergraduates, endodontic program students, and specialists (52, 63.1, 77.9 and 86.5% respectively). Fractured instruments and missed canals were noted in 9.8% and 0.57% of cases treated by endodontic program students significantly more than the other clinical experiences. No statistical differences were found among the clinical experiences in other procedural errors. No statistically significant differences were found between age range and gender in additional root canals. Statistically significant differences were observed between the number of root canal retreatments in terms of age range and gender. Conclusions: Clinical experience affects the technical quality of root canal treatments. Fractured instruments and missed canals, especially by endodontic program students, should be given more attention. (AU)


Objetivo: O objetivo do estudo foi avaliar a qualidade técnica de 9562 casos endodônticos tratados por grupos heterogêneos com diferentes experiências clínicas. Material e métodos:Este estudo retrospectivo revisou os registros dentários de 8590 pacientes (9562 casos endodônticos e 13203 canais radiculares, incluindo 3340 canais radiculares de retratamento) tratados por graduandos do quarto ano, graduandos do quinto ano, estudantes do programa endodôntico e especialistas em endodontia, entre dezembro de 2017 e dezembro de 2018 no Departamento de Endodontia da Faculdade de Odontologia da Universidade Necmettin Erbakan em Konya. O comprimento, a densidade e a conicidade dos preenchimentos das raízes, a qualidade técnica aceitável dos critérios de preenchimento das raízes e a presença de erros processuais foram registrados. Os testes de qui-quadrado com nível de significância de p = 0,05 foram utilizados para análise estatística. Resultados:O preenchimento radicular aceitável foi encontrado em 71,5% dos casos endodônticos. A experiência clínica mostrou diferenças estatísticas na qualidade do preenchimento das raízes entre os alunos do quarto ano, do quinto ano, estudantes do programa endodôntico e especialistas (52, 63,1, 77,9 e 86,5%, respectivamente). Instrumentos fraturados e canais perdidos foram observados em 9,8% e 0,57% dos casos tratados pelos estudantes do programa endodôntico significativamente mais do que nas outras experiências clínicas. Não foram encontradas diferenças estatísticas entre as experiências clínicas em outros erros processuais. Não foram encontradas diferenças estatisticamente significantes entre faixa etária e sexo em canais radiculares adicionais. Foram observadas diferenças estatisticamente significantes entre o número de retratamentos do canal radicular em termos de faixa etária e sexo. Conclusões: A experiência clínica afeta a qualidade técnica dos tratamentos do canal radicular. Instrumentos fraturados e canais perdidos, especialmente por estudantes do programa endodôntico, devem receber mais atenção (AU)


Asunto(s)
Humanos , Estudiantes de Odontología , Radiografía Dental , Cavidad Pulpar , Educación
13.
J Prosthodont ; 2020 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-33290604

RESUMEN

PURPOSE: To measure the chemical composition, Knoop hardness, surface roughness, and composite bond strength of additive manufactured (AM) and conventional interim materials. MATERIAL AND METHODS: Disks were prepared using conventionally (CNV group) and additively manufactured (AM group) materials: CNV-1 (Protemp 4; 3M ESPE), CNV-2 (Anaxdent new outline dentin; Anaxdent), AM-1 (FreePrint temp; Detax), AM-2 (E-Dent 400 C&B MFH; Envisiontec), AM-3 (NextDent C&B MFH; 3D Systems), and AM-4 (Med620 VEROGlaze; Stratasys). Each group was subdivided into 3 subgroups (n = 20) for analyzing Knoop hardness (KHN), chemical composition, superficial roughness (Ra), and composite shear bond strength. The first subgroup was exposed to a microhardness test. Subsequently, EDAX analysis was selected to analyze the chemical composition. The second subgroup was selected to measure the superficial roughness (Ra) using a contact profilometer. The third subgroup was used to measured composite shear bond strength using a universal testing apparatus. A digital microscope was used to analyze the fracture mode. The Shapiro-Wilk test showed normally distributed data. One-way ANOVA and post hoc Sidak tests were selected (α = .05). RESULTS: Major variances in chemical composition were observed among the specimens. Significant differences in Knoop hardness (P<.001) and surface roughness (P<.001) were detected. The AM-4 (13.45 ±2.93 KHN), the CNV-2 (13.35 ±5.84 KHN), the AM-2 (13.03 ±3.29 KHN), and the AM-1 (12.55 ±2.93 KHN) groups obttained the highest Knoop hardness values, followed by the AM-3 and the CNV-1 groups (P<.05). The AM-1 group (1.88 ±1.11 Ra) obtained the highest surface roughness values among the groups, followed by the AM-3 group (0.90 ±0.14 Ra) (P<.05). However, no significant differences in shear bond strength values were found between the groups ranging from 23.18 ±8.88 MPa to 33.29 ±9.17 MPa (P = .061). All the groups showed a cohesive mode of failure. CONCLUSIONS: The AM interim materials tested had significant chemical composition variations compared to conventional materials. For the mechanical properties evaluated, the AM materials obtained appropriate mechanical properties for use as an interim dental restoration. However, further studies are required to evaluate more extensively its mechanical properties and verify their applicability in the oral cavity, clinical behavior, and biocompatibility. This article is protected by copyright. All rights reserved.

14.
Int J Mol Sci ; 21(23)2020 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-33291724

RESUMEN

Additive manufacturing is a key technology required to realize the production of a personalized bone substitute that exactly meets a patient's need and fills a patient-specific bone defect. Additive manufacturing can optimize the inner architecture of the scaffold for osteoconduction, allowing fast and reliable defect bridging by promoting rapid growth of new bone tissue into the scaffold. The role of scaffold microporosity/nanoarchitecture in osteoconduction remains elusive. To elucidate this relationship, we produced lithography-based osteoconductive scaffolds from tricalcium phosphate (TCP) with identical macro- and microarchitecture, but varied their nanoarchitecture/microporosity by ranging maximum sintering temperatures from 1000 °C to 1200 °C. After characterization of the different scaffolds' microporosity, compression strength, and nanoarchitecture, we performed in vivo studies that showed that ingrowth of bone as an indicator of osteoconduction significantly decreased with decreasing microporosity. Moreover, at the 1200 °C peak sinter temperature and lowest microporosity, osteoclastic degradation of the material was inhibited. Thus, even for wide-open porous TCP-based scaffolds, a high degree of microporosity appears to be essential for optimal osteoconduction and creeping substitution, which can prevent non-unions, the major complication during bone regeneration procedures.

15.
J Appl Oral Sci ; 28: e20200122, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33263669

RESUMEN

METHODOLOGY: This paper aims to evaluate the effect of different surface treatments on surface topography, wettability, and shear bond strength of resin cement to glass ceramic. For SBS test, 32 blocks (7x7x2 mm) of lithium disilicate were obtained and randomly divided into eight groups (four blocks per group) according to each surface treatment (HF 20 s, 60 s, 120 s + silanization/S or Scotch Bond Universal/ SBU) and the Monobond Etch & Prime - MEP application followed or not by SBU. On each treated surface ceramic block, up to four dual-curing resin cement cylinders were prepared and light-cured for 40s (N=120/n=15). The specimens were thermocycled (10,000 cycles, 5-55°C, 30 s) and the SBS test (50KgF, 0.5 mm/min) was performed. Furthermore, failure analysis, wettability, AFM, and SEM were carried out. SBS data (MPa) were analyzed using Student's t-test, two-way ANOVA, Tukey's test (5%) and Weibull's analysis. RESULTS: For HF experimental groups, two-way ANOVA presented the factors "etching time" and "bonding agent" as significant (p<0.05). After silane application, the HF groups presented similar bond strength. SBU application compromised the SBS, except for 120s etching time (HF120sS: 23.39ᵃ±6.48 MPa; HF120sSBU: 18.76ᵃ±8.81MPa). For MEP groups, SBU application did not significantly affect the results (p=0.41). The MEP group presented the highest Weibull modulus (4.08A) and they were statistically different exclusively from the HF20sSBU (0.58B). CONCLUSION: The HF 20s, 60s, 120 s followed by silane, promoted similar resin-bond strength to ceramic and the SBU application after HF or MEP did not increase the SBS.

16.
J Esthet Restor Dent ; 2020 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-33188586

RESUMEN

OBJECTIVE: This study aimed to assess the impact of monolithic zirconia thickness on its color properties after different surface finishing and polishing procedures, and following aging in coffee solution. MATERIALS AND METHODS: Two types of monolithic zirconia brands [Prettau Anterior (PA) and DD Cubex2 (DDC)] with three different thicknesses: 0.5, 1, and 1.5, and 10 mm diameter were tested. The color properties were evaluated after various surface finishing procedures (glazing, adjusting with burs + glaze, polishing, adjusting with burs + polishing) and after 5,000 cycles in a coffee solution were evaluated. The differences in color (ΔE) and translucency, were calculated and statistically analyzed by three-way ANOVA and pairwise comparison (α = 0.05). RESULTS: The brand, material thickness, and surface finishing protocol before and after coffee thermocycling had significant effect on color variations (p < 0.001). For translucency, 3-way ANOVA revealed a significant interaction between the material thickness and surface finishing protocol following aging in coffee solution (p < 0.001), however no significant interaction was observed following the surface finishing protocols (p = 0.247). CONCLUSIONS: The optical properties of monolithic zirconia ceramics can be influenced by the material brand, material thickness and the procedure of surface finishing and polishing. CLINICAL SIGNIFICANCE: Clinicians should take into consideration the potential change of the color properties of monolithic zirconia restorations following both contouring and occlusal adjustment procedures and coffee intake.

17.
Dent Mater J ; 2020 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-33162456

RESUMEN

To investigate and analyze the impact of teeth preparation designs and sintering protocol on marginal fit and fracture resistance of monolithic translucent zirconia laminate veneers. A total of 40 extracted intact human maxillary central incisors were assigned into 4 groups (n=10/each group) to investigate 2 variables: (1) the design of tooth preparation (a 1.5 mm incisal reduction with or without palatal chamfer) and (2) the two different sintering programs used for translucent zirconia restoration (standard or speed sintering procedure). Marginal discrepancy was evaluated using a digital microscope. The specimens were loaded to failure in the compression mode, using a universal testing machine with a crosshead speed of 0.5 mm/min. Marginal adaptation of monolithic translucent zirconia laminates are affected by both tooth preparation design and sintering protocol. However, resistance to fracture of translucent zirconia laminates has affected mainly by sintering procedure regardless the teeth preparation design used.

18.
Odontology ; 2020 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-33128650

RESUMEN

This study aims to compare the degree of conversion of two different curing protocols used during adhesive cementation. The following resin luting agents were tested: Hri Flow (MF) and pre-heated Hri Micerium (MH); light-cure Nexus Third Generation (NX3L) and dual-cure Nexus Third Generation (NX3D); dual cured RelyX Ultimate (RXU) and light-cure RelyX Veneers (RXL). For each tested material, ten samples were prepared and divided into two groups which had different curing protocols (P1 and P2): in P1, samples were cured for 40 s; in P2, samples were cured for 5 s, and then, after 20 s, cured again for additional 40 s. The degree of conversion (DC) was evaluated both during the first 5 min of the curing phase and after 1, 2, 7, 14 and 28 days (p = 0.05). Different trends were observed in DC values after 5 min by comparing P1 and P2. In both P1 and P2, DC decreased as follows, MH > MF > NX3L > RXL > RXU > NX3D. There were significant differences of DC values among all resin luting agents (p < 0.05) in P1, while no significant differences existed between MH and MF, and NX3L and RXL in P2. At 1, 2, 7, 14 and 28 days the light curing luting agents had a higher DC than the dual luting agents (p < 0.05). P1 and P2 were not statistically different at each time point (p > 0.05). Both P1 and P2 protocols let achieve an acceptable DC after 28 days. The tested P2 can be safely used to lute indirect restorations, simplifying the removal of cement excesses.

19.
Biomed Res Int ; 2020: 7912638, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33062699

RESUMEN

This study evaluated the long-term clinical outcomes of single-visit root canal treatments with apical enlargement on patients with necrotic pulp tissue retrospectively. A total of 137 teeth with necrotic pulp tissue which underwent single-visit root canal treatments were included. The root canals were shaped up until the apical constriction, which was determined by an apex locator. The outcomes were evaluated by two independent and calibrated endodontists clinically and radiographically. Teeth were dichotomized into healed (PAI ≤ 2, no signs or symptoms) and nonhealed (PAI > 2, with/without signs or symptoms) groups. Each patients' preoperative PAI and lesion size were recorded to evaluate the preoperative periapical status as well as several other prognostic factors. Statistical analyses were performed (p = 0.05) on ninety teeth. The mean observation time was 60 months. Out of ninety teeth, 87 (96.7%) were healed and 3 (3.3%) were nonhealed. No correlations were found between the prognostic factors and the outcomes (p > 0.05). Cohen's kappa and Gwet's agreement coefficient scores between the preoperative PAI scores and preoperative lesion sizes showed good agreements, with values of 0.834 and 0.898, respectively. Apical enlargement is a viable treatment option for single-visit root canal treatments.

20.
J Prosthodont ; 2020 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-32864812

RESUMEN

PURPOSE: To evaluate the color stability of CAD/CAM complete denture resins. MATERIALS AND METHODS: A total of 176 resin specimens were manufactured from conventional heat-polymerizing (pink: CONHCP : n = 16; tooth-shade: CONHCT : n = 16), CAD/CAM subtractively manufactured (pink: WIMP : n = 16, AVMP : n = 16, MEMP : n = 16, POMP : n = 16; tooth-shade: AVMT : n = 16, MEMT : n = 16, POMT : n = 16), and additively manufactured (pink: NDRPP : n = 16; tooth-shade: NDRPT : n = 16) denture resins; four different aging processes (thermal cycling, distilled water, red-wine, and coffee) were used. A spectrophotometer evaluated the color change (ΔE) using two modes of measurements (specular component included (ΔESCI ) and specular component excluded (ΔESCE )) recorded at baseline (T0 ) and at day#30 (T30 ). ANOVA and post hoc tests were used for statistical analysis (alpha = 0.05). RESULTS: Additively manufactured resins (NDRPP and NDRPT ) demonstrated significant ΔE in comparison to the other groups in all aging media (p < 0.001). WIMP demonstrated higher ΔESCI in comparison to the other subtractively manufactured groups in distilled water (p < 0.001). In red-wine, AVMT revealed significantly more ΔESCE than POMT (p = 0.039). In coffee, the ΔESCE was higher for CONHCT than MEMT (p = 0.026) and POMT (p = 0.011). Similarly, in coffee the ΔESCE for AVMT was higher than POMT (p = 0.030). CONCLUSION: Additively manufactured denture resins demonstrated the maximum color change compared to conventional heat-polymerized and CAD/CAM subtractively manufactured denture resins. Furthermore, CAD/CAM subtractively manufactured denture resins were not inferior to conventional resins in terms of color stability.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...