Effect of the nanofilm-coated zirconia ceramic on resin cement bond strength.

Background. New surface treatments have been proposed to expand the clinical indications of zirconia prostheses. This study aimed to evaluate the effect of silica and fluorine nanofilms on zirconia ceramic on the resin cement bond strength. Methods. Zirconia blocks and discs underwent different surface treatments: untreated zirconia (CON), sandblasted, silica-coated alumina particles (30 µm) (SC), silica nanofilm (SN), and fluorine nanofilm (FN). Nanofilm deposition was performed through plasma enhanced chemical vapor deposition (PECVD). Zirconia surfaces were characterized on disks by morphology (atomic force microscopy, AFM), chemical analysis (x-ray photoelectron spectroscopy, XPS), and contact angle analysis. A silane coupling agent was applied on each treated surface, and a cylinder of resin cement was built up. Half of the specimens in each group were submitted to 6000 thermal cycles (TC). Bond strength was analyzed using the shear test, and the fractographic analysis was performed with stereomicroscopy and SEM/EDS. Statistical analysis was performed through one-way ANOVA and Tukey test in the non-aged and aged specimens. Results. Nanofilms modified the zirconia surface, which became more hydrophilic and chemically reactive. Chemical bonding between Si-O was found in SN, and FN promoted a fluorination process on the ceramic surface, converting zirconia into zirconium oxyfluoride. Specimens of the SN (TC) group failed on pre-testing. FN (TC) bond strength (3.8 MPa) was lower than SC (TC) and CON (TC) after shearing. Adhesive failure predominated in the experimental groups. Silica nanofilm failure occurred after aging. Conclusion. Silica and fluorine nanofilms deposited by PECVD did not promote effective bonding between zirconia and resin cement.

The Effect of Water or Wax-based Binders on the Chemical and Morphological Characteristics of the Margin Ceramic-Framework Interface.

This study evaluated the effect of binder choice in mixing ceramic powder on the chemical and morphological features between the margin ceramic-framework interfaces. Titanium and zirconia frameworks (15 x 5 x 0.5 mm3) were veneered with margin ceramics prepared with two different binders, namely a) water/conventional or b) wax-based. For each zirconia framework material, four different margin ceramics were used: a- Creation Zi (Creation Willi Geller International); b- GC Initial Zr (GC America); Triceram (Dentaurum); and d- IPS emax (voclar Vivadent). For the titanium framework, three different margin ceramics were used: a- Creation Ti (Creation Willi Geller International); b- Triceram (Dentaurum); and c- VITA Titaniumkeramik (Vita Zahnfabrik). The chemical composition of the framework-margin ceramic interface was analyzed using Energy Dispersive X-ray Spectroscopy (EDS) and porosity level was quantified within the margin ceramic using an image program (ImageJ) from four random areas (100 x 100 pixels) on each SEM image. EDS analysis showed the presence of Carbon at the margin ceramic-framework interface in the groups where wax-based binder technique was used with the concentration being the highest for the IPS emax ZirCAD group. While IPS system (IPS ZirCAD and IPS Emax) presented higher porosity concentration using wax binder, in the other groups wax-based binder reduced the porosity of margin ceramic, except for Titanium - Triceram combination.

Degree of chronic orofacial pain associated to the practice of musical instruments in orchestra's participants.

OBJECTIVE: The practice of playing musical instruments can affect structures of the head, neck, mouth, and the masticatory system. The aim of this study was to obtain information regarding the prevalence of orofacial pain in musicians according to the type of instrument they play, by applying a specific questionnaire. MATERIALS AND METHODS: One hundred and seventeen musicians of Sao Paulo state's orchestras participated in this study. They answered an anamnesis questionnaire with 20 questions regarding their personal data, type of instrument played, hours of daily practice, and presence or absence of orofacial pain according to the Chronic Pain Grade Classification (CPGC). Musicians were divided into two groups in accordance with the risk of affecting TMJ: RG (risk group, including violin, viola, vocalist, trombone, tuba, clarinet and saxophone); CG (control group, other instruments). They received an informative brochure about the subject. Data obtained from the questionnaire were submitted to descriptive statistics, Pearson's correlation analysis and Z-test for difference between two proportions. RESULTS: The participants were from 15 to 62 years old. Pain degree showed positive correlation for reported symptoms (P = 0.002) and hour/day practice (P = 0.030). Regarding the prevalence of pain degree, data were, for RG: Grade 0 (54.5%), Grade 1 (30.3%), and Grade ≥2 (15.1%). For CG, Grade 0 (84.4%), Grade 1 (8.9%), and Grade ≥2 (6.6%). Z-test showed positive difference between groups (P = 0.0001). CONCLUSION: It was concluded that the musicians of risk group presented higher prevalence of orofacial pain than control (non-risk) group.

Influence of silane heat treatment on bond strength of resin cement to a feldspathic ceramic.

This study evaluated the influence of heat treatment (HT) of the silane on the microtensile bond strength of resin cement to a feldspathic ceramic. Ceramic (VITA VM7) and composite blocks (N=32) were divided into four groups (n=6 for bond test, n=2 for SEM) at random and subject to following sequence of conditioning: G1: HF 9.6%+Silane+Panavia F2.0, G2: HF 9.6%+Silane+HT+Panavia F2.0, G3: Silane+HT+Panavia F2.0, and G4: Silane+Panavia F2.0. HT was performed in an oven (100°C, 2 minutes). G1 (17.6±2.3 MPa) and G2 (19±3.2 MPa) showed significantly higher mean bond strength than those of G3 (9.1±2.8 MPa) and G4 (10.9±1.8 MPa). SEM analysis showed exclusively mixed failures. Silane HT did not increase the bond strength.