Bonding plays a major role in dentistry nowadays. Dental adhesives are used in association with composites to solve many restorative issues. However, the wide variety of bonding agents currently available makes it difficult for clinicians to choose the best alternative in terms of material and technique, especially when different clinical situations are considered. Moreover, although bonding agents allow for a more conservative restorative approach, achieving a durable adhesive interface remains a matter of concern, and this mainly due to degradation of the bonding complex in the challenging oral environment. This review aims to present strategies that are being used or those still in development which may help to prevent degradation. It is fundamental that professionals are aware of these strategies to counteract degradation as much as possible. None of them are efficient to completely solve this problem, but they certainly represent reasonable alternatives to increase the lifetime of adhesive restorations.

<p><strong>Objective: </strong>This study investigated the influence of different surface treatments on zirconia surface energy, roughness and microshear bond strength. <strong>Material and Methods:</strong> Forty eight slices of Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP- VITA In-Ceram® YZ for inLab®) (6.4 x 3.2 x 1.6 mm) were divided into 3 groups according to the surface treatment (n = 16): YTZP_control -untreated; YTZP_plasma -surface treatment with non-thermal oxygen plasma; YTZP_primer - coating with ceramic primer. Surface energy (n = 6) was measured with a goniometer; and surface roughness (n = 10) was analyzed with a 3D profilometer were performed over zirconia surface. On the same specimens of surface roughness, on the treated zirconia's surface, resin cement (PANAVIA V5 - Kuraray Noritake Dental) was built up by inserting the resin cement into Tygon tubes (1 mm of internal diameter X 1 mm length).  After 24 h storage, microshear test was assessed. Data were analyzed by one-way ANOVA and Tukey post-hoc test (<em>p </em>&lt; 0.05). <strong>Results:</strong> Non-thermal oxygen plasma treated specimens exhibited higher statistically significant surface energy (<em>p </em>= 0.00) and bond strength (<em>p </em>= 0.00) when compared to control and primer groups. Roughness test (<em>p </em>= 0.897) could not detect statistical difference among the tested groups. <strong><br /> Conclusion: </strong>Non-thermal oxygen plasma should be a suitable alternative for zirconia surface treatment prior to luting hence it improved microshear bond strength and provided higher surface energy without affecting surface roughness.</p><p> </p><p><strong>Keywords                                                                                                   </strong></p><p>Adhesion; Non-thermal plasma; Surface treatment.</p>

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This study investigated the effect of irradiation with an erbium‐doped yttrium aluminium garnet (Er:YAG) laser and coating with silica on the surface characteristics, bond strength, and flexural strength of dental zirconia. Three hundred and forty‐three standard zirconia specimens were created, and 49 were assigned to each of seven surface treatment groups: (i) no treatment; Er:YAG laser (80 mJ/2 Hz) with pulse widths of 50 μs (ii), 100 μs (iii), 300 μs (iv), or 600 μs (v); or tribochemical silica coating at the partially sintered stage (vi) or after sintering was complete (vii). All specimens were sintered after the surface treatments, except for the group in which specimens were sintered before treatment. The study outcomes were roughness, surface loss, microshear bond strength (μSBS), and biaxial flexural strength (BFS). Mean roughness and surface loss values were significantly higher in specimens from irradiated groups than in those from silica‐coated groups. Regarding μSBS, after aging, specimens from all experimental groups presented very low and similar μSBS values, irrespective of the surface treatment. Silica coating after sintering yielded the highest BFS (1149.5 ± 167.6 MPa), while coating partially sintered specimens with silica resulted a BFS (826.9 ± 60.9 MPa) similar to that of the untreated control group (794.9 ± 101.7 MPa). Laser treatments, irrespective of pulse width used, significantly decreased the BFS. In the group treated with laser at 300 μs pulse width, specimens exhibited the lowest BFS value (514.1 ± 71.5 MPa). Adhesion to zirconia was not stable after aging, regardless of the surface treatment implemented.

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Objetivo: Analisar efeitos de diferentes envelhecimentos sobre a rugosidade e a cor de cimentos de ionômero de vidro (CIV) encapsulados. Materiais e métodos: Foram testados dois cimentos de ionômero de vidro [convencional/ Self Cure (SC) e resino modificado/Light Cure (LC)] e envelhecimentos [(baseline, pós-ciclagem térmica e pós- -ciclagem térmica + armazenamento por sete meses)]. 52 discos (n = 13) foram confeccionados. A cor foi avaliada por dois espectrofotômetros (VITA Easyshade e Konica Minolta CE3700A), e a rugosidade pelo perfilômetro óptico (Proscan 2100, Scantron). Resultados: ANOVA dois fatores e teste de Tukey (p < 0,05) foram realizados. Os CIVs apresentaram diferenças estatisticamente significantes entre si (p < 0,05) para rugosidade (SC = 0,202 μm e LC = 0,241), os envelhecimentos alteraram significativamente a rugosidade baseline = 0,278 μm, ciclado = 0,220 μm e ciclado-armazenado = 0,167 μm, e para cor (SC ΔE = 3,89 e o LC ΔE = 4,94). Para ΔL*, Δa*, Δb* houve diferença na interação dos fatores, com maior alteração do ΔL* para o CIV LC após ciclagem + armazenagem. Para Δa* houve diferença estatisticamente significante (p < 0,05) entre os envelhecimentos, sendo maior para o grupo CIV LC após ciclagem. Maior alteração Δb* foi observada para o CIV LC após ciclagem + armazenagem. Conclusões: Os diferentes CIVs possuem rugosidade superficial e cor diferentes. O CIV LC mostrou-se mais rugoso quando comparado ao SC, porém ambos se tornaram menos rugosos com o passar do tempo. O protocolo de envelhecimento que mais interfere na rugosidade e na cor de diferentes tipos de CIV é a ciclagem térmica seguida de armazenamento.

Purpose: This study aims to evaluate the effect of erosive, abrasive, and erosive/ abrasive challenges on the glaze layer of ceramic materials. Methods: Ninety-five samples of monolithic zirconia (MZ) (LuxaCam Zircon HT-Plus) and lithium disilicate (LD) (IPS e.max CAD) were divided according to the response variables: Surface roughness and surface loss (n = 10), evaluated with optical profilometry; surface topography, with scanning electron microscopy SEM (n = 3); and biofilm deposition, with microbiological assay (n = 5). The evaluations were performed in three different time evaluations: (a) Sintered, (b) Glaze, and (c) Challenge (Erosion, Abrasion, and Erosion/Abrasion). Erosion consisted in immersing specimens in HCl solution, abrasion was performed with brushing machine, and erosion/abrasion consisted of a combination of the two previous protocols. Data were analyzed with parametric tests (P < 0.05). Results: MZ glaze layer presented significantly higher surface roughness (P = 0.00), surface loss (P = 0.03), and biofilm deposition (P = 0.00) than LD. Abrasion and erosion/abrasion showed similar outcomes, generating significantly higher surface roughness (P = 0.00), surface loss (P = 0.00), and biofilm deposition (P = 0.01) than erosion. Conclusions: Glaze layer properties were altered by the challenges, with abrasion and erosion/abrasion generating higher surface roughness, surface loss, and biofilm deposition than erosion. A significant correlation was found between the surface roughness and biofilm deposition. Clinical significance: The glaze layer is susceptible to challenges, especially to abrasion and erosion/abrasion, which generated greater surface roughness and surface loss than erosion. The greater surface roughness lead to a greater biofilm deposition on the glaze layer.

Silva BTF. Effect of temporal width pulse of Er:YAG laser on surface characteristics, bond strength and mechanical properties of zirconia [thesis].