Searched for: person:rh1694
Effect of phosphoric acid etching and blasting with aluminum oxide on the enamel topography and adhesion of resin composite to intact or abraded enamel
Rifane, Tainah Oliveira; Hirata, Ronaldo; Araújo-Neto, Vitaliano Gomes; Ottoboni, Thiago; Feitosa, Victor Pinheiro; Giannini, Marcelo
OBJECTIVES/OBJECTIVE:particles (BL) on the bonding of a dental adhesive to intact (INT) or abraded (ABR) enamel. METHODS:particles were characterized using SEM and EDX. The enamel bond strength was measured by microtensile test (24 h and 1 year) (n = 8) and the morphology of enamel-adhesive interfaces were analyzed by SEM (n = 3). Bond strength data were analyzed by two-way ANOVA and Tukey's test (α = 0.05). RESULTS:particles had an irregular shape, their length varied (50-20 µm) and the perimeter mean was 38.8 µm. The enamel morphology significantly influenced the enamel bond strength. ABR-PA, INT-BL, and INT-BA provided greater and stable enamel-dentin interaction and bond strength. SIGNIFICANCE/CONCLUSIONS:-blasted when used in SE mode.
PMID: 39155186
ISSN: 1879-0097
CID: 5681332
Influence of viscosity and fiber reinforcement of resin composite on fracture strength and failure mode of restored molars
Borges, Karin Tyeme; ServÃn, MarÃa Paz Méndez; França, Fabiana Mantovani Gomes; Turssi, Cecilia Pedroso; Basting, Roberta Tarkany; Hirata, Ronaldo; Vieira-Junior, Waldemir Francisco
OBJECTIVE:To evaluate the fracture behavior of human molars with extensive MOD restorations using short-fiber-reinforced resin composite of varying viscosities. MATERIALS AND METHODS/METHODS:Human molars were randomly divided into seven groups (n = 12): intact teeth (control); restoration using conventional high-viscosity resin composite without (Filtek Z350XT, 3M) or with fibers (everX Posterior, GC); conventional low-viscosity resin composite without (Filtek Supreme Flowable, 3M) or with fibers (everX Flow Dentin Shade, GC); bulk-fill low-viscosity resin composite (Filtek Bulk Fill Flow, 3M) or with fibers (everX Flow Bulk Shade, GC). Restorations were performed on extensive MOD preparations, following the manufacturers' recommendations for each material. Specimens underwent fracture strength testing (N) and fracture pattern (%) categorized as repairable, possibly repairable, or non-repairable. Results were analyzed using a generalized linear model (N) and Fisher's exact test (%), with α = 0.05. RESULTS:Restorations performed with high-viscosity materials showed fracture strength values similar to the control and higher than those of restorations using low-viscosity resin composites (p < 0.0001), except for the bulk-fill low-viscosity resin composite with fibers (p > 0.05). Teeth restored using low-viscosity resin composite with fibers showed a higher % of repairable and possibly repairable fractures than the control (p = 0.0091). CONCLUSIONS:The viscosity of materials mediated the fracture strength, with restorations using high-viscosity resin composites promoting values similar to the intact tooth; however, the presence of fibers influenced the fracture pattern. CLINICAL SIGNIFICANCE/CONCLUSIONS:Teeth with MOD cavities restored with high-viscosity resin composites showed similar fracture strength to intact teeth. Fiber-reinforced low-viscosity resin composite for the base of restoration resulted in a more repairable/possibly repairable fracture pattern.
PMID: 39095320
ISSN: 1708-8240
CID: 5711022
Transitioning from injectable resin composite restorations to resin composite CAD/CAM veneers: A clinical report
Rafeie, Niyousha; Sampaio, Camila S; Hirata, Ronaldo
OBJECTIVE:To describe a shift from injectable resin composite technique to composite resin computer-aided design and computer-aided manufacturing (CAD/CAM) veneers in addressing esthetic concerns associated with diastemas between anterior lower teeth in a clinical case. CLINICAL CONSIDERATIONS/METHODS:Among several techniques proposed for direct resin composite restoration, the "Injectable resin composite technique" has gained popularity for its time-efficiency, reduced technique sensitivity, and diminished reliance on clinician skills. However, challenges such as staining and the need for frequent polishing follow-ups may prompt the consideration of more stable alternatives such as indirect veneer restorations. While ceramic veneers offer superior mechanical and optical properties, resin ceramic veneers, especially those milled from CAD/CAM resin ceramic blocks, offer advantages such as rapid, cost-effective production, simplified intra-oral repairs, less susceptibility to fracture, superior stress absorption, and requires minimal tooth preparation, making them an appealing option for many patients. Moreover, a fully-digital approach not only streamlines the process but also saves time and labor while ensuring the delivery of high-quality restorations to patients. CONCLUSION/CONCLUSIONS:In addressing a patient's dissatisfaction with constant polishing of direct resin composite restorations, a shift to resin composite CAD/CAM veneers was implemented. Utilizing a fully-digital approach with CAD/CAM resin ceramic restorations successfully restored both esthetics and function. CLINICAL SIGNIFICANCE/CONCLUSIONS:While the injectable resin composite technique achieves immediate esthetic results, its low color stability necessitates frequent polishing sessions. The replacement of direct resin composite restorations with CAD/CAM resin composite veneers becomes a viable option for patients seeking more stable restorations that require fewer follow-ups. This transition addresses both esthetic concerns and the need for enduring solutions in restorative dentistry.
PMID: 38546152
ISSN: 1708-8240
CID: 5645482
Effect of gastric acids on the mechanical properties of conventional and CAD/CAM resin composites - An in-vitro study
Gil-Pozo, Alexandra; Astudillo-Rubio, Daniela; Ferrando Cascales, Ãlvaro; Inchingolo, Francesco; Hirata, Ronaldo; Sauro, Salvatore; Delgado-Gaete, Andrés
OBJECTIVES/OBJECTIVE:Dental erosion in patients with gastroesophageal reflux disease (GERD) is a current and frequent condition that may compromise the mechanical properties and clinical durability of resin-based composites (RBCs). This study assessed the mechanical properties of conventional and computer-aided design/computer-aided manufacturing (CAD/CAM) RBCs subsequent to simulated gastric acid aging. MATERIALS AND METHOD/METHODS:Three conventional and three CAD/CAM composites were assessed. They were divided into an experimental group (exposed to simulated gastric acid aging) and a control group (no aging). Both groups were analyzed for Vickers microhardness (VHN), wear and flexural strength over a period of six months. The failure rate probability for each RBC was calculated through the Weibull cumulative distribution function (m). Statistical analysis was conducted using repeated measures ANOVA, 3-way ANOVA, a non-parametric Kruskal-Wallis and U Mann-Whitney tests (α = 0.05). RESULTS:The mechanical properties of all the RBCs dropped significantly after aging (p < 0.05). Lower VHN and flexural strength values, along with greater wear values were evident in the experimental groups, though the effects of the treatment varied between RBCs. The Weibull m of all the RBCs decreased over time. CONCLUSION/CONCLUSIONS:Conventional RBCs might show greater reduction in mechanical properties compared to CAD/CAM RBCs when exposed to gastric acid attack. Thus, CAD/CAM composites may represent a suitable choice for the treatment of patients presenting erosive issues.
PMID: 38718723
ISSN: 1878-0180
CID: 5658412
A fully digital low-cost workflow of a multidisciplinary minimally invasive treatment: step-by-step from function to esthetics [Case Report]
Olcay, Vania; Atria, Pablo; Hirata, Ronaldo; Sampaio, Camila
This clinical case outlines a comprehensive digital workflow for a minimally invasive multidisciplinary treatment. The process utilizes one open-source software for digital wax-up and one low-cost software to address esthetic concerns related to teeth misalignment. The patient's function was stabilized with a digitally made occlusal splint. The application of the described digital workflow technique, incorporating open-source, low-cost, and closed software, played a pivotal role in attaining a straightforward and predictable outcome with minimally invasive treatment. Furthermore, the continual evolution of technology contributes to the growing precision of dental procedures. The presented digital workflow helped formulate a predictable treatment plan, replicate a diagnostic digital wax-up, and achieve precise teeth alignment. This approach satisfactorily addressed the patient's esthetic concerns, providing an outstanding approximation of the definitive result.
PMID: 38374723
ISSN: 1936-7163
CID: 5657092
Ultrathin lithium disilicate and translucent zirconia crowns for posterior teeth: Survival and failure modes
Benalcazar Jalkh, Ernesto B; Ramalho, Ilana S; Bergamo, Edmara T P; Alves, Larissa M M; Tanaka, Ricardo; Witek, Lukasz; Coelho, Paulo G; Hirata, Ronaldo; Bonfante, Estevam A
PURPOSE/OBJECTIVE:To evaluate the reliability and failure modes of ultrathin (0.5 mm) lithium disilicate, translucent and ultra-translucent zirconia crowns for posterior teeth restorations. MATERIALS AND METHODS/METHODS:Fifty-four mandibular first molar crowns of three ceramic materials: (1) Lithium disilicate (e.max CAD, Ivoclar Vivadent), (2) 3Y-TZP (Zirconn Translucent, Vipi), and (3) 5Y-PSZ (Cercon XT, Dentsply Sirona), with 0.5 mm of thickness were milled and cemented onto composite resin abutments. Eighteen samples of each group were tested under mouth-motion step-stress accelerated life testing in a humid environment using mild, moderate, and aggressive profiles. Data was subjected to Weibull statistics. Use level curves were plotted and reliability was calculated for a given mission of 100,000 cycles at 100, 200, and 300 N. Fractographic analyses of representative samples were performed in scanning electron microscope. RESULTS:Beta (β) values suggest that failures were dictated by material's strength for lithium disilicate and by fatigue damage accumulation for both zirconias. No significant differences were detected in Weibull modulus and characteristic strength among groups. At a given mission of 100,000 cycles at 100 N, lithium disilicate presented higher reliability (98% CB: 95-99) regarding 3Y-TZP and 5Y-PSZ groups (84% CB: 65%-93% and 79% CB: 37&-94%, respectively). At 200 N, lithium disilicate reliability (82% CB: 66%-91%) was higher than 5Y-PSZ (20% CB: 4%-44%) and not significantly different from 3Y-TZP (54% CB: 32%-72%). Furthermore, at 300 N no significant differences in reliability were detected among groups, with a notable reduction in the reliability of all materials. Fractographic analyses showed that crack initiated at the interface between the composite core and the ceramic crowns due to tensile stress generated at the intaglio surface. CONCLUSIONS:Ultrathin lithium disilicate crowns demonstrated higher reliability relative to zirconia crowns at functional loads. Lithium disilicate and zirconia crown's reliability decreased significantly for missions at higher loads and similar failure modes were observed regardless of crown material. The indication of 0.5 mm thickness crowns in high-load bearing regions must be carefully evaluated. CLINICAL SIGNIFICANCE/CONCLUSIONS:Ultraconservative lithium disilicate and zirconia crowns of 0.5 mm thickness may be indicated in anterior restorations and pre-molars. Their clinical indication in high-load requirement regions must be carefully evaluated.
PMID: 37676053
ISSN: 1708-8240
CID: 5625542
Analysis of translucency parameter and fluorescence intensity of 5 resin composite systems
Hirata, Ronaldo; de Abreu, João-Luiz-Bittencourt; Benalcázar-Jalkh, Ernesto-Byron; Atria, Pablo; Cascales, Ãlvaro-Ferrando; Cantero, Jon-Salazar; Sampaio, Camila-Sobral
The natural outcome of dental composite restorations highly depends on the translucency of the enamel layer and fluorescence. This study aimed to evaluate the Translucency Parameter (TP) and Fluorescence Intensity (FI) of five different resin composite systems. Seven discs of each composite brand were prepared in a circular increasing thickness. For TP, a spectrophotometer measured the samples' colors. The color difference within the white/black backgrounds obtained the translucency parameter. For FI, samples were exposed to UV light, and ten photographs per group were taken. Each specimen was analyzed digitally. A mixed model analysis to a 95% confidence level analyzed groups differences. Higher values of TP were observed for ED and EL, followed by FZ. The lowest values were observed for EO and FO. FI values descending order was EL>FO>EO>ED>FZ. The composition of fillers and organic matrix influenced the behavior of fluorescence and translucency of resin composites. Key words:Resin composite, fluorescence, color, translucency parameter.
PMCID:10837799
PMID: 38314337
ISSN: 1989-5488
CID: 5633262
Quo vadis, esthetic dentistry? Part II: Composite resin overtreatment and social media appeal
Hirata, Ronaldo; Hilgert, Leandro Augusto; Sampaio, Camila S; de Andrade, Oswaldo Scopin; Melo, Ginger; Ritter, André V
OBJECTIVES/OBJECTIVE:This article presents case reports highlighting over-treatments with resin composites, often misconceived as minimally invasive procedures. CLINICAL CONSIDERATIONS/METHODS:Tooth-colored restorative materials, such as ceramics and composites, have found widespread application to correct problems related to tooth color, shape, and alignment. When composite resin is used, these procedures can be done in a very conservative, cost-effective, and timely fashion. However, it is noteworthy that contemporary dental esthetic expectations are based on standards propagated by social media and other marketing and communications platforms. The abuse of and addiction to social media impacts can lead to unrealistic esthetic expectations and standards for both patients and dentists. CONCLUSIONS:After a critical discussion on ceramic veneers published in part I of this 2-part series, this article directs attention towards what has become a trendy fashion, i.e., the use of direct composite resins as "non-prep" veneers in clinical situations that arguably required no restorative intervention at all. We further explore how social media influences the decision-making processes of both professionals and patients.
PMID: 38142060
ISSN: 1708-8240
CID: 5623722
Short curing time bulk fill composite systems: volumetric shrinkage, degree of conversion and Vickers hardness
Sampaio, Camila Sobral; Abreu, João Luiz Bittencourt de; Kornfeld, Batsheva; Silva, Eduardo Moreira da; Giannini, Marcelo; Hirata, Ronaldo
This study aimed to evaluate volumetric polymerization shrinkage, degree of conversion and Vickers hardness of four bulk-fill resin composites light-activated with their dedicated light curing units (LCUs). Four groups were evaluated, according to the type of composite and curing mode: Tetric EvoCeram Bulk-fill (TEBO) and Tetric EvoFlow Bulk-fill (TEBF) were light-activated with Bluephase Style 20i (20s, in high-mode), while Tetric Powerfill (TEPO) and Tetric Powerflow (TEPF) were light-activated with Bluephase PowerCure (3s). Volumetric polymerization shrinkage test (n = 6) was performed in standardized box-shaped class-I cavities of extracted third molars (4 x 4 x 4 mm). Teeth were scanned before and after resin composite application by micro-computed tomography, and acquired data were evaluated with Amira software. Degree of conversion (n = 5) was evaluated at the top and bottom surfaces of composite cylindric samples (4 mm diameter, 4 mm thickness) using an FT-IR spectrometer (spectra between 1,500 and 1,800 cm-1, 40 scans at a resolution of 4 cm-1). Three Vickers indentations (50 g / 15 s), spaced 500 μm apart, were performed on the top and bottom composite surfaces and averaged. One-way ANOVA was used for data evaluation. TEPF showed the lowest volumetric polymerization shrinkage (p < 0.05), while the other composites were not significantly different within each other (p > 0.05). All materials presented a significant decrease in degree of conversion and Vickers hardness when compared top to bottom surfaces (p < 0.05). Bottom to top surface ratios for degree of conversion ranged from 0.8 (TEBO and TEPO) to 0.9 (TEBF and TEPF), and from 0.4 (TEPO) to 0.7 (TEBF and TEPF) for hardness. In conclusion, resinous materials present a decrease in hardness and degree of conversion from top to bottom even when a higher power is used, while the flowable material TEPF showed the lowest volumetric shrinkage values compared to the other materials.
PMCID:11376680
PMID: 38597548
ISSN: 1807-3107
CID: 5741712
Total Rehabilitation Using Adhesive Dental Restorations in Patients with Severe Tooth Wear: A 5-Year Retrospective Case Series Study
Ferrando Cascales, Ãlvaro; Sauro, Salvatore; Hirata, Ronaldo; Astudillo-Rubio, Daniela; Ferrando Cascales, Raúl; AgustÃn-Panadero, Rubén; Delgado-Gaete, Andrés
INTRODUCTION/BACKGROUND:Currently, there is little clinical evidence to support the medium- and long-term survival and clinical performance of ultraconservative approaches using adhesive restorations in full-mouth restorations. The aim of this case series study was to evaluate the medium-term clinical performance of anterior and posterior adhesive restorations applied with direct and indirect techniques using resin composites and glass-ceramic-based materials. MATERIALS AND METHODS/METHODS:The inclusion criteria were an esthetic problem as the main reason for consultation and severe generalized wear of grade 2 to 4 according to the Tooth Wear Evaluation System (TWES 2.0). In addition, at each follow-up appointment, patients were required to submit a clinical-parameter-monitoring record according to the modified United States Public Health Service (USPHS) criteria. RESULTS:< 0.005) on the survival of the restorations. CONCLUSION/CONCLUSIONS:According to the results of this study, there is a significantly higher risk of restorative complications in posterior teeth compared to anterior teeth. Also, it can be concluded that the indication of adhesive anterior and posterior restorations is justified in the total oral rehabilitation of patients with severe multifactorial tooth wear, as they are associated with a low risk of failure.
PMCID:10455517
PMID: 37629264
ISSN: 2077-0383
CID: 5599582