Amalgam x Composite Resin: supplies and restorative procedures more performed among Oral Health Teams in Brazil

Abstract This study aimed to compare the availability of supplies and amalgam and composite resin restorations among Oral Health Teams (OHT) in Brazilian regions. Secondary data were extracted from Modules I and II of the 1st (2012) and V and VI of the 2nd (2014) and 3rd cycle (2017) of the external evaluation of the National Program for Access and Quality in Primary Care2. The proportions between regions and cycles were compared using the Chi-square test with the z-test adjusted by the Bonferroni method (p<0.05). Among 2012, 2014, and 2017 there was a significant reduction in the proportion of OHT that performed amalgam restorations (87.5%, 89.2%, and 80.2%; p<0.001) and an increase in resin composite (92.5 %, 97.7%, and 99.0%; p<0.001), with the same trend in Brazilian regions (p<0.001). Amalgamator availability decreased among 2012 (99.0%), 2014 (98.4%) and 2017 (85.6%) (p<0.001). Amalgam availability was lower in 2017 (80.1%), compared to 2012 (87.5%) and 2014 (97.5%) (p<0.001). The availability of light curing decreased between 2012 (99.0%), 2014 (98.4%) and 2017 (85.6%) (p<0.001), being less available in the North (95.7%) (p<0.001). The light-curing resin increased between 2012 (94.1%), 2014 (96.6%) and 2017 (97.0%) (p<0.001), with no increase only in the North (p=0.134). While there was a reduction in supplies and amalgam restoration, there was an increase in supplies and resin composite restorations in the period evaluated in all Brazilian regions. However, regional disparities are still evident, with fewer supplies of restorative services in the North region.

Resumo Este estudo objetivou comparar a disponibilidade de fornecimentos e restaurações de amálgama e resina composta entre as Equipas de Saúde Oral (OHT) por regiões brasileiras. Os dados secundários foram extraídos dos módulos I e II do 1º (2012) e V e VI do 2º (2014) e 3º ciclo (2017) da avaliação externa do Programa Nacional de Acesso e Qualidade em Cuidados Primários. As proporções entre regiões e ciclos foram comparadas utilizando o teste Qui-quadrado com o teste z ajustado pelo método de Bonferroni (p<0,05). Entre 2012, 2014, e 2017 houve uma redução significativa na proporção de OHT que realizou restaurações de amálgama (87,5%, 89,2%, e 80,2%; p<0,001) e um aumento na resina composta (92,5%, 97,7%, e 99,0%; p<0,001), com a mesma tendência nas regiões brasileiras (p<0,001). A disponibilidade de amalgamadores diminuiu entre 2012 (99,0%), 2014 (98,4%) e 2017 (85,6%) (p<0,001). A disponibilidade de amálgama foi menor em 2017 (80,1%), em comparação com 2012 (87,5%) e 2014 (97,5%) (p<0,001). A disponibilidade de polimerização por luz diminuiu entre 2012 (99,0%), 2014 (98,4%) e 2017 (85,6%) (p<0,001), estando menos disponível no Norte (95,7%) (p<0,001). A resina fotopolimerizadora aumentou entre 2012 (94,1%), 2014 (96,6%) e 2017 (97,0%) (p<0,001), sem aumento apenas no Norte (p=0,134). Embora tenha havido uma redução nos fornecimentos e restauração de amálgamas, houve um aumento nos fornecimentos e restaurações de resina composta no período avaliado em todas as regiões brasileiras. Contudo, as disparidades regionais são ainda evidentes, com menos oferta de serviços de restauração na região Norte.

Effect of Simulated Gastric Acid on the Interface Between Zirconia and Resin Cement

PURPOSE: To evaluate the effect of simulated gastric acid solution (SGAS) and resin cement composition on the shear bond strength (SBS) of zirconia-based materials with different levels of translucency to composite resin. MATERIALS AND METHODS: A total of 40 medium-opacity (MO; 3Y-TZP) and 40 medium-translucency (MT; 4Y-PSZ) zirconia slabs were distributed into four groups according to the composition of the resin luting system (MDP free or with MDP [primer + Panavia V5]) and storage method (distilled water or SGAS [5% hydrochloric acid]). Composite resin cylinders were cemented on the zirconia surface and stored for 91 hours. SBS, failure mode, and surface characterization analyses via scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were performed. SBS data were analyzed using three-way ANOVA and Tukey test, and failure mode was assessed using one-way ANOVA (P < .05). RESULTS: Storage media (P = .180), resin cement (P = .110), zirconia (P = .404), and their interactions did not affect SBS values. Bond strength ranged from 21.41 to 26.11 MPa. SEM images showed that SGAS modified the surface topography of zirconia and resin cement. The presence of chlorine and silicon (wt%) were higher after SGAS storage than after water storage in both cements used, while barium was higher only for the MDP cement. There was a prevalence of mixed failures for most of the groups. CONCLUSION: The SBS between both types of zirconia and resin cement was not affected by SGAS, although changes in zirconia topography were observed after SGAS exposure. The presence of MDP in the cement layer had no effect on the SBS challenged by SGAS.

MIH-Affected Teeth: Clinical Challenges from Diagnosis to Restorative Management.

Teeth affected by molar incisor hypomineralization (MIH) present micromorphologic changes and hypersensitivity, which increase the risk of developing caries lesions and affect bonding procedures. Considering that practitioners still misdiagnose teeth affected by MIH, there is an urge for more knowledge about this topic in order to propose a more adequate and conservative treatment. The purpose of this study was to report the clinical challenges regarding the restorative management of a patient with MIH. A 13-year-old girl sought dental treatment, complaining about hypersensitivity in posterior teeth. Under clinical exams, notable enamel alterations mainly affecting posterior teeth (including molars) presented particular characteristics frequently attributed to MIH, and visible stains on maxillary central incisors were present. Because the mineral and organic content of MIH-affected enamel differ from sound enamel, it may imply special care for bonding of a restorative material. Thus, in order to promote a minimally invasive approach, selective removal of carious tissue and restoration with microhybrid composite resin was conducted after application of a universal bonding system used as self-etching strategy. After a 2-year follow-up, the restorations presented good clinical performance and the patient had limited hypersensitivity discomfort, suggesting a promising performance.

Silica deposition on zirconia via room-temperature atomic layer deposition (RT-ALD): Effect on bond strength to veneering ceramic.

PURPOSE: To develop and to characterize a hybrid interface between yttria-stabilized zirconia (Y-TZP) transformed layer and silica-based nanofilm to enable a better bonding between Y-TZP and a veneering ceramic. MATERIAL AND METHODS: Sixty-six fully-sintered rectangular Y-TZP specimens were distributed into 6 groups, according to the surface treatment applied: C (control): no treatment; Al: 27 µm-alumina particle abrasion; Ht: hydrothermal treatment in autoclave for 15h; Si20: 20 cycles of silica deposition using room-temperature atomic layer deposition (RT-ALD); Si40: 40 cycles of RT-ALD; Ht + Si40: hydrothermal treatment followed by 40 cycles of RT-ALD. RT-ALD was performed by the sequential exposure of specimens to vapor of tetramethoxysilane orthosilicate (TMOS) and ammonium hydroxide (NH4OH). Y-TZP surface wettability and shear bond strength (SBS) between Y-TZP and the veneering ceramic were analyzed for all groups after surface treatments. One-way ANOVA and Tukey's HSD test were used for data analysis (p ≤ 0.05). RESULTS: The highest contact angle was observed for the control group (64.46 ± 6.09 θ), while the lowest values (p < 0.001) were presented after Si20 (29.85 ± 4.23 θ) and Si40 (30.37 ± 5.51 θ) treatments. Hydrothermal treatment (49.3 ± 2.69 θ) and alumina abrasion (45.84 ± 4.12 θ) resulted in intermediate contact angle values. The highest SBS values were observed for Al (16.74 ± 1.68 MPa) and Ht (15.27 ± 2.11 MPa) groups (p < 0.018). Groups Si20 (9.66 ± 1.22 MPa), Si40 (9.33 ± 2.11 MPa), Ht + Si40 (9.37 ± 1.02 MPa) and C (12.54 ± 2.64 MPa) all resulted in similar SBS results (p > 0.998). CONCLUSION: The experimental treatments proposed enhanced surface wettability, but shear bond strength between Y-TZP and veneering ceramic was not improved. Alumina particle-abrasion improved SBS values while a decrease in wettability was observed.

Surface characterization of different surface treatments associations with plasma and bonding analysis of Y-TZP and the veneering ceramic.

OBJECTIVES: To characterize the surface of zirconia (Y-TZP) submitted to different surface treatments (with and without plasma associations) and to evaluate the shear bond strength (SBS) between veneering ceramic (VC) and Y-TZP after different aging methods. METHODS: 301 Y-TZP specimens were fabricated and distributed into 7 groups: C (control): no treatment; Al: airborne abrasion with 27 µm Al2O3 particle; L: liner; P: plasma; Al + L: airborne + liner; Al + P: airborne + plasma; P + L: plasma + liner. The Y-TZP surface was characterized by SEM, EDS, AFM, surface profilometry, surface-free energy (SFE), and XRD. SBS between Y-TZP and VC was verified after three aging protocols: initial, after hydrothermal aging (autoclave for 5 h), or thermal fatigue (30,000 baths - 5-55 °C). One- (profilometry, SFE) and two-way ANOVA (SBS), and Tukey's HSD test were used. RESULTS: For the plasma groups, a full globular surface coverage was observed (SEM, AFM). Si was found for Al, L, Al + L, and P + L. Roughness was lower for C, P, and Al + P. For SFE, the highest values were found when the liner was applied (>74.59 nm/Nm). The highest monoclinic content was observed for Al + L (6.96%) and Al + P (5.86%). For the initial period, Al and P + L presented the lowest SBS values (<5.85 MPa; P > 0.331). The highest SBS values were found for L, P, and P + L (hydrothermal aging) and for P, L, Al + L, and Al + P (thermal fatigue). SIGNIFICANCE: Changes in Y-TZP topography and the SBS with the VC were found, according to treatments performed. Plasma treatment improved SBS and did not cause phase transformation.

Mechanical performance of a hybrid zirconia developed through hydrothermal treatment and Room-Temperature Atomic Layer Deposition (RT-ALD).

OBJECTIVE: A silica-based nanofilm has been successfully deposited via Room-Temperature Atomic Layer Deposition (RT-ALD) on the surface of a glass. The purpose of this study was to evaluate the mechanical performance of a hybrid interface created between yttria-stabilized zirconia (Y-PSZ) transformed layer and silica-based nanofilm via RT-ALD. MATERIAL AND METHODS: Fully-sintered Y-PSZ (14 × 4.0 × 1.5 mm) specimens in different translucencies (MO, MT, LT; IPS e.max Zircad, Ivoclar Vivadent) were distributed in 5 groups: control (C - no treatment); hydrothermal treatment (HT- 15h, 134°C, 2 bar); alumina blasting (B - 50 µm Al2O3); RT-ALD silica deposition (S); HT followed by silica deposition (HTS). RT-ALD cycles consisted of the sequential exposure of specimens to tetramethoxysilane orthosilicate (TMOS - 60s) and ammonium hydroxide (NH4OH - 10 min) vapors in 40 cycles. Mechanical performance was analyzed by flexural strength (FS) (n = 10) and fatigue failure load (staircase method; n = 20) tests. Surface hardness (H) and Young's modulus (YM) were analyzed by nanoindentation. For surface chemical and topographical characterization, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were performed. Data from surface H, YM, FS, and fatigue limit (FL) were analyzed by two-way analysis of variance (ANOVA). RESULTS: The interaction between material and treatment had a significant effect on FS (p < 0.001). The FS values ranged from 436.23 MPa to 856.65 MPa. HT resulted in the highest FS (856.65 MPa) for LT and the lowest FS (436.23 MPa) for MO zirconia. For all materials, S and B treatments resulted in similar FS values (p > 0.410). S did not affect FL when compared to the C group (p > 0.277) for any material investigated. HTS resulted in higher FL than S for LT and MO materials (p < 0.001). Surface hardness and modulus were similar between control and S-treated specimens for all materials analyzed. XPS analysis showed homogeneous silica content after 20 and 40 RT-ALD cycles, and SEM did not show significant changes in surface morphology between C and S-treated specimens. CONCLUSION: RT-ALD resulted in effective silica deposition without any deleterious effect on zirconia-based materials mechanical properties. Alumina blasting promoted higher alteration on surface topography. HT prior to S resulted in superior FL (for MO and MT) and flexural strength (MO) for some of the materials investigated.