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Opalescence and color stability of composite resins: an in vitro longitudinal study

Pepelascov, Daniele Esteves; de Castro-Hoshino, Lidiane Vizioli; da Silva, Leandro Herculano; Hirata, Ronaldo; Sato, Francielle; Baesso, Mauro Luciano; Centenaro, Alex Sandro; Novatski, Andressa; Neto, Antonio Medina; Terada, Raquel Sano Suga
OBJECTIVES/OBJECTIVE:This study aims to evaluate the opalescence (OP) and color stability of composite resins over a period of 180 days and to compare composite resins' OP with enamel's OP. MATERIALS AND METHODS/METHODS:Twenty human enamel specimens (5.0 × 0.3 mm) and 9 specimens (10.0 × 1.0 mm) of 10 colors of 4 different composite resins (3 M ESPE, FGM, Ivoclar-Vivadent, Miscerium) and one brand of adhesive (3 M ESPE) were made. The results were obtained by measuring the reflectance and transmittance spectra in the visible region. After baseline measurement, composites and adhesive were analyzed after 2, 7, 30, 60, 120, and 180 days. The Lab color coordinates were used in the calculations of the OP parameter and color differences in the CIELab and CIEDE2000 methods. The data were analyzed statistically. RESULTS:The materials tested showed variation and an increase in OP over time. The OP found for enamel was 18.06 ± 2.99, and some resins showed higher results. There was a strong correlation between the coordinate b*T and the OP over time. Enamel Plus was the only one material that presented no color changes during all periods in both color analyses. Filtek Z350 XT, AT, and BT did not show differences in any time when analyzed by CIELAB. CONCLUSIONS:The OP of most composite resins changed during the period of 180 days and was different from the OP of tooth enamel. In general, composites demonstrated small color changes over the period tested, being this characteristic material dependent. CLINICAL RELEVANCE/CONCLUSIONS:Natural teeth present different optical properties. Composite resins restorations should present properties similar to natural teeth and it is important that characteristics like color and opalescence remain stable over time.
PMID: 34697656
ISSN: 1436-3771
CID: 5068262

Comparison of the operative time and presence of voids of incremental and bulk-filling techniques on Class II composite restorations

Soto-Montero, Jorge; Giannini, Marcelo; Sebold, Maicon; de Castro, Eduardo F; Abreu, João L B; Hirata, Ronaldo; Dias, Carlos T S; Price, Richard B T
OBJECTIVES/OBJECTIVE:To compare the operative time and presence of air voids on Class II restorations fabricated by dental practitioners with 1 to 5 years of experience using incremental and bulk-filling techniques. METHOD AND MATERIALS/METHODS:Four techniques were evaluated: incremental, bulk-filling, bulk-filling with heated composite, and snowplow technique. Standardized mandibular first molars with a MOD (mesial, occlusal, and distal) cavity were used. Voluntary operators made two restorations using each technique and the time required for each restoration was recorded. The restorations were scanned by micro-computed tomography to calculate the volume of the restoration occupied by air voids. The "operative time" and "volume of air voids" were analyzed individually by two-way ANOVA and Tukey HSD post hoc (α = .05) for the factors operator and insertion technique. A correlation between "operative time" and "volume of air voids" was evaluated using Pearson coefficient (α = .05). RESULTS:The incremental technique required significantly longer time, yet no differences were observed between the bulk-filling techniques. There were no significant differences between techniques regarding the volume of air voids. A significant, but weak, and inverse linear correlation (P = .0059; r = -.29; r2 = 8.41%) was found between the operative time and volume of air voids. CONCLUSION/CONCLUSIONS:There were no significant differences in the volume of air voids among the evaluated techniques, although bulk-filling techniques required a shorter operative time. Hence, implementing bulk-filling techniques by dental schools and restorative dental practitioners with different levels of expertise may reduce chair time and produce a volume of air voids similar to the incremental technique.
PMID: 34709774
ISSN: 1936-7163
CID: 5183252

Effect of Argon Plasma Surface Treatment on Repair of Resin Composite Aged Two Years

Negreiros, W M; Ayres, Apa; Willers, A E; Hirata, R; Giannini, M
OBJECTIVES/OBJECTIVE:To evaluate the effect of argon plasma treatment (PLA) when combined with sandblasting (SAN), silanization (SIL), and hydrophobic bonding resin (HBR) on the shear bond strength (SBS) of a two-year water-aged resin composite bonded to a newly placed composite after 24 hours and one year of water-storage. METHODS AND MATERIALS/METHODS:Thirty-six light-cured composite plates (20mm x 20mm x 4mm thick) were obtained and stored at 37°C in distilled water for 2 years. These aged plates were distributed into 6 groups (n=6) according to the surface treatment: no treatment (Negative Control); SAN+SIL+HBR (Positive Control); SAN+PLA+SIL+HBR; PLA+ SIL+HBR; PLA+SIL; PLA+HBR. Fresh resin composite cylinders were built up using silicone molds (hole: 1.5 mm high x 1.5 mm diameter) positioned over the aged plates. Half of the SBS samples were stored in distilled water for 24 hours and loaded until failure, while the other half were stored for 1 year before being tested. Data were submitted to two-way analysis of variance and post-hoc Tukey Test (preset alpha of 0.05). RESULTS:Positive Control, SAN+PLA+SIL+HBR and PLA+SIL+HBR groups presented higher SBS means at the 24 hour evaluation. After 1 year of water storage, all groups demonstrated significant SBS reduction, with the SAN+PLA+SIL+HBR group presenting the highest SBS. CONCLUSIONS:Resin plasma treatment in combination with other surface treatments can improve the SBS of composite repairs after one year of water storage. The SBS of the composite repair was not stable over time regardless of the surface treatment.
PMID: 35584286
ISSN: 1559-2863
CID: 5253402

Quo vadis, esthetic dentistry? Ceramic veneers and overtreatment-A cautionary tale

Hirata, Ronaldo; Sampaio, Camila S; de Andrade, Oswaldo Scopin; Kina, Sidney; Goldstein, Ronald E; Ritter, Andre V
The increased emphasis on orofacial esthetics, experienced both by dental professionals and the lay public, results in an environment where overtreatment can easily occur. Patients on the one hand feel pressure from esthetic norms that are often unrealistic, while dental professionals are compelled to deliver immediate results many times without considering what is best for the ill-informed patient. This article is an illustrated cautionary tale against overtreatment disguised as esthetic dentistry. Representative clinical examples illustrate how porcelain veneers are used without following sound operatory principles, as well as how these cases have been resolved.
PMID: 34792281
ISSN: 1708-8240
CID: 5068392

Effect of different tightening protocols on the probability of survival of screw-retained implant-supported crowns

Fardin, Vinicius P; Bergamo, Edmara T P; Bordin, Dimorvan; Hirata, Ronaldo; Bonfante, Estevam A; Bonfante, Gerson; Coelho, Paulo G
PURPOSE/OBJECTIVE:This study evaluated the effect of different tightening protocols on the probability of survival of screw-retained implant-supported anterior crowns. MATERIALS AND METHODS/METHODS:Seventy-two implants with internal conical connections (4.0 × 10mm, Ti-6Al-4V, Colosso, Emfils) were divided into four groups (n = 18 each): 1) Manufacturer's recommendations torque (25 for abutment's screw and 30 for crown's screw) (MaT); 2) Retightening after 10 min (ReT); 3) Torque 16% below recommended to simulate an uncalibrated wrench (AgT), and; 4) Temporary crown simulation (TeT), where crowns were torqued to 13 to simulate manual tightening, subjected to 11,200 cycles to simulate temporary crown treatment time (190 N), and then retightened to manufacturer torque (TeT). All specimens were subjected to cyclic fatigue in distilled water with a load of 190 N until 250,000 cycles or failure. The probability of survival (reliability) to complete a mission of 50,000 cycles was calculated and plotted using the Weibull 2-Parameter analysis. Weibull modulus and number of cycles at which 62.3% of the specimens would fail were also calculated and plotted. The failure mode was characterized in stereo and scanning electron microscopes (SEM). RESULTS:The probability of survival was 69.3% for MaT, 70% for ReT, 54.8% for AgT, and 40.3% for TeT, all with no statistically significant difference. Weibull modulus was approximately 1.0 for all groups. The characteristic number of cycles for failure was 105,000 cycles for MaT, 123,000 for ReT, 82,000 cycles for AgT, and 54,900 cycles for TeT, with no significant difference between groups. The chief failure mode for MaT, ReT, AgT groups was crown screw fracture, whereas abutment screw fracture was the chief failure mode for the TeT group. CONCLUSION/CONCLUSIONS:Tightening protocol did not influence the probability of survival of the screw-retained anterior crowns supported by internal conical implants (Ti-6Al-4V, Colosso, Emfils).
PMID: 34875501
ISSN: 1878-0180
CID: 5099562

Evaluation of trueness and precision of two intraoral scanners and a conventional impression: an in vivo clinical study

Jorquera, Gilbert J; Sampaio, Camila S; Bozzalla, Antonia; Hirata, Ronaldo; Sánchez, Juan Pablo
OBJECTIVE:To evaluate, in vivo, trueness and precision of two intraoral scanners, CEREC Omnicam (OMNI) and CEREC Primescan (PRIM), compared to a conventional impression serving as a master model. METHOD AND MATERIALS/METHODS:Impressions were performed for seven participants. For each participant, conventional polyvinylsiloxane impression and digital impressions using two intraoral scanners, OMNI (software 4.6; CEREC ORTHO Protocol) and PRIM (10 digital impressions per participant, per scanner), were made. Conventional impression was digitized with a laboratory scanner (INEOS X5), and used as reference model. .STL files were superimposed with software (Geomagic Control X) using the tools Initial Alignment and Best Fit Alignment, and trueness and precision were evaluated. Statistical evaluation was performed with Shapiro-Wilk and Mann-Whitney tests (P < .05). RESULTS:Total mean trueness for the OMNI system was 56.45 ± 7.80 µm, and 47.29 ± 5.47 µm for the PRIM system. Regarding precision, values from the OMNI system were 42.47 ± 6.91 µm and from the PRIM system 21.86 ± 4.40 µm. PRIM presented better results for both trueness (P = .000) and precision (P = .000) when compared to OMNI. CONCLUSIONS:PRIM provided a better combination of trueness and precision than its predecessor OMNI. However, both PRIM and OMNI performed acceptably when performing indirect restorations, according to the current acceptable thresholds, considering both trueness and precision. CLINICAL IMPLICATIONS/CONCLUSIONS:Full-arch impressions with Primescan presented more precision and trueness than Omnicam; however, compared to previous reported values of conventional impressions, they still presented lower accuracy.
PMID: 34410071
ISSN: 1936-7163
CID: 5072062

Effect of argon plasma on repair bond strength using nanofilled and microhybrid composites

Negreiros, William Matthew; Ayres, Ana Paula Almeida; Willers, Amanda Endres; Hirata, Ronaldo; Giannini, Marcelo
OBJECTIVES/OBJECTIVE:To evaluate the effect of atmospheric pressure plasma (PLA), sandblasting (SAN), silanization (SIL) and hydrophobic bonding resin (HBR) on the micro-shear bond strength (MSBS) of fresh nanofilled (NF) or microhybrid (MH) composites to water-aged nanofilled composite. MATERIALS AND METHODS/METHODS:NF plates were fabricated and stored in distilled water for 4 months. The aged plates were assigned to the groups (n = 6): 1- untreated; 2- SAN + SIL + HBR; 3- HBR; 4- PLA + HBR; 5- SAN + HBR; 6- SAN + PLA + HBR; and 7- PLA. Two fresh composite cylinders were constructed on each plate with NF or MH composites and tested after 24 h or 1 year of water-storage, using the MSBS testing. Data were analyzed by three-way ANOVA and Tukey test (α = 0.05). RESULTS:NF yielded better outcomes than MH at 24 h, which was not observed at 1 year. HBR showed the highest MSBS results, while untreated and PLA groups yielded the lowest one. MSBS reduced for all groups after 1 year. CONCLUSIONS:Only HBR can obtain good MSBS results, while PLA alone was not beneficial. After 1 year, a reduction in repair MSBS was observed and the type of composite did not influence the results. CLINICAL RELEVANCE/CONCLUSIONS:The repair technique can be simplified with the use of only an adhesive and macromechanical retentions in the old composite, regardless the type of fresh composite.
PMID: 33881792
ISSN: 1708-8240
CID: 4847172

Full-mouth adhesive rehabilitation of a severe case of erosion treated with v-shaped veneers

Dallari, Giacomo; Scalzo, Ivan; Rosati, Riccardo Maria; Sampaio, Camila Sobral; Hirata, Ronaldo
OBJECTIVE:To demonstrate a minimally invasive approach of a full-mouth rehabilitation of a severe case of erosion treated with v-shaped veneers, tabletops, overlays, veneerlays, laminate veneers, and a full contour veneer. CLINICAL CONSIDERATIONS/UNASSIGNED:The present case report successfully rehabilitated a full-mouth case of severely eroded teeth with minimal healthy structure removal, maintaining viability of all teeth that were vital before the treatment started, and promoting long-lasting esthetic and functional results after 3 years of use. CONCLUSIONS:A deep knowledge of etiology, etiopathogenesis, and classifications of dental erosion will guide the clinician in the right direction for solving this issue correctly, according to modern prosthetic and conservative principles. CLINICAL SIGNIFICANCE/CONCLUSIONS:Dental erosion represents today a relatively widespread phenomenon among the global population and a significant challenge in each of its clinical stages for the clinicians who must treat it. In advanced stages, a careful evaluation phase of the case, a great patient motivation and a wise use of materials and clinical protocols are the success key of the case. Moreover, an advanced knowledge of adhesive dentistry is strictly required to successfully manage a severe erosion case with a modern and minimally invasive approach.
PMID: 33460516
ISSN: 1708-8240
CID: 4760252

The injectable resin composite restorative technique: A case report

Ypei Gia, Nathalia Ramos; Sampaio, Camila Sobral; Higashi, Cristian; Sakamoto, Antonio; Hirata, Ronaldo
OBJECTIVE:To describe the use of the injectable resin composite restorative technique with a flowable resin material, in a clinical case with esthetic problems associated with irregular tooth anatomies, allied with a finishing, and polishing protocol due to staining after 1 year of use. CLINICAL CONSIDERATIONS/UNASSIGNED:The presented case report helped to achieve an immediate highly esthetic restoration with appropriate width proportions based on a previous wax-up. After 1 year of use, restorations presented staining; therefore, finishing and polishing procedures were required to re-achieve acceptable esthetic results and thus increase restoration's survival. CONCLUSIONS:The use of the presented technique allowed to obtain a simple and predictable workflow; however, care must be taken on the follow up of the restorations due to intrinsic characteristics of the flowable resin material. CLINICAL SIGNIFICANCE/CONCLUSIONS:The use of the presented injectable technique helped on obtaining a precise anatomy replicating a diagnostic wax-up, thus improving marginal precision and achieving a highly esthetic and functional immediate outcome, with an easy workflow when appropriately planned and executed. However, it also presented low color stability after 1 year of use only, thus, requiring attention from clinicians in regard to its maintenance over time.
PMID: 32918395
ISSN: 1708-8240
CID: 4592262

Microcomputed tomography evaluation of cement film thickness of veneers and crowns made with conventional and 3D printed provisional materials

Sampaio, Camila S; Niemann, Katherin D; Schweitzer, Daniel D; Hirata, Ronaldo; Atria, Pablo J
OBJECTIVE:To evaluate, through microcomputed tomography (μCT), the cement film thickness of veneers and crowns made with different provisional materials. MATERIAL AND METHODS/METHODS:A veneer and a crown preparation were performed on a central incisor and a second molar of a dental model, respectively, scanned with an intraoral scanner, and the .stl files were exported to an LCD-based SLA three-dimensional (3D)-Printer. Twenty-four preparations were 3D-printed for each veneer and crown and divided into four groups (n = 6/group): (a) Acrylic resin (Acrílico Marche); (b) Bisacrylic resin (Protemp 4); (c) PMMA computer-aided design and computer-aided manufacturing (CAD-CAM) (Vipiblock); and (d) 3D-printed resin for provisional restorations (Raydent C&B for temporary crown and bridge). Veneers and crowns restorations were performed and cemented with a flowable composite. Each specimen was scanned with a μCT apparatus, files were imported for data analysis, and cement film thickness was quantitatively measured. Data were analyzed by 2-way ANOVA and Tukey post-hoc tests (α = .05). RESULTS:Crowns presented a thicker cementation film than veneers (P < .05).The bisacrylic resin showed the smallest veneer film thickness, similar to the acrylic resin (P = .151), which was not significantly different than the PMMA CAD/CAM material (P = .153). The 3D printed provisional material showed the thicker film, different than all other materials (P < .05). The bisacrylic resin showed a cement film thickness with a high number of voids in its surface. For crowns cementation, the 3D printed provisional material showed the thicker cementation film, different than all other materials (P < .05). CONCLUSIONS:Different provisional materials present different film thicknesses. The 3D printed provisional material showed the highest veneer and crown film thicknesses. Veneers film thicknesses were smaller than crowns for all provisional materials. CLINICAL SIGNIFICANCE/CONCLUSIONS:The 3D printed provisional material studied can be satisfactorily used, presenting appropriate adaptation with the tooth preparation, however, it shows the highest cement film thickness for both veneers and crowns cementations when compared with other provisional materials. A better internal fit, or smaller cement film thickness is obtained by CAD/CAM materials, acrylic and bisacrylic resins. Veneer cementation showed a smaller cement film thickness compared with crown cementation for all provisional materials.
PMID: 32937028
ISSN: 1708-8240
CID: 4593142