Biomedical subjects

Evandro Piva

Publications and source records attributed to Evandro Piva.

7 recordsLinked to original sources

PubMed2006

Microleakage of seven adhesive systems in enamel and dentin.

AIM: The aim of this study was to evaluate the microleakage of seven adhesive systems on two substrates (enamel and dentin). METHODS AND MATERIALS: Class V cavities were performed in buccal and lingual surfaces of 56 bovine incisors. The cervical margin was located in dentin and the incisal margin in enamel. The specimens were randomly divided into seven groups (n=16), according to the adhesive system employed: Single Bond; Excite; One Step Plus; Gluma One Bond; Magic Bond; One Up Bond F; and One Coat Bond. The cavities were incrementally filled with a hybrid composite Filtek Z250 and polymerized with a XL 3000 light curing unit. After polishing, the specimens were submitted to thermal cycling followed by dye immersion. Leakage was evaluated under magnification (40X) based on a standard ranking. Data were subjected to statistical analysis (Kruskal-Wallis). RESULTS: Enamel margins exhibited lower leakage than dentin margins (p<0.01). The majority of the specimens were leakage-free and materials performed similarly. Conversely, in dentin most of the specimens exhibited the highest leakage degree and significant differences among materials (p<0.05) were found, with Excite exhibiting the lowest leakage degree. It was concluded enamel provided better sealing and the adhesive system was a significant factor only in dentin.

Adhesives↗

PubMed2006

Immunohistochemical expression of fibronectin and tenascin after direct pulp capping with calcium hydroxide.

The aim of this study was to investigate the expression of 2 extracellullar matrix glycoproteins, fibronectin (FNC) and tenascin (TNC), following direct pulp capping with calcium hydroxide (CH). Third molars scheduled for extraction were used. Standardized class I cavities with pulp exposures were prepared. After control of bleeding, CH powder was applied in the exposure sites, which were covered with CH cement (Dycal; Dentsply) and the cavities were filled with zinc oxide-eugenol cement. Three teeth were extracted at each post-treatment period (1, 7, 14, and 30 days). Demineralized and paraffin-embedded specimens were stained for histologic technique (hematoxylin-eosin) and for immunohistochemical analysis. Anti-TNC and anti-FNC monoclonal antibodies were used with the streptavidin-biotin complex method. Generally, similar patterns of immunohistochemical expression were observed for TNC and FNC in the pulp tissue as a whole. In the exposure site, TNC immunostaining increased over time, exhibiting a thicker immunostaining pattern within 30 days. The imunohistochemical technique showed expression of both glycoproteins during pulp healing process.

Calcium Hydroxide↗

PubMed2005

2,3-Epithiopropyl methacrylate as functionalized monomer in a dental adhesive.

OBJECTIVES: The aim of this study was to investigate new dentin bonding agents formulated with 2,3-epithiopropyl methacrylate (ETMA) comonomer blends. METHODS: Synthesis and characterization of ETMA were performed. Adhesive resins with three different ETMA concentrations (0.1, 1 and 10 wt.%) were prepared. To comparison a blend with only Bis-GMA/HEMA and with 1% of GMA were used as controls. FTIR analysis was used to verify the degree of conversion. Blend copolymerization was investigated by (1)H NMR spectroscopy analysis. To investigate immediate properties of experimental adhesives, microtensile bond strength to human dentin and SEM fractographic analysis were studied. RESULTS: ETMA was synthesized with 90% yield through a one step synthetic route. Degree of conversion for the experimental and control resins was not significantly different. Different monomers showed copolymerization among them, not presenting traces of ETMA release in 0.1 and 1% groups. Bonding agents containing ETMA had statistically higher microtensile bond strength values than the no ETMA adhesive (p<0.05). CONCLUSIONS: Dental adhesive resin-ETMA mixtures produced increased bond strengths without harming the other properties investigated.

Bisphenol A-Glycidyl Methacrylate↗

PubMed2004

Microleakage in bonded amalgam restorations using different adhesive materials.

The aim of this study was to verify the ability of different adhesive materials to prevent microleakage in bonded amalgam restorations. Standard cavities were prepared in both buccal and lingual surfaces of 35 bovine incisors. The gingival wall was located in cementum/dentin and the occlusal wall in enamel. Teeth (n=35) were divided into 5 groups, according to material employed (one glass-ionomer cement, two resin cements, one adhesive system, and Copalex varnish as a control). Following restoration, the teeth were submitted to thermal cycling. The teeth were subsequently immersed in methylene blue dye and sectioned to allow assessment of microleakage. Non-parametric statistical analysis indicated that all materials demonstrated less leakage than the control group (p<0.01). No leakage was found using the resin-modified glass-ionomer cement, which was significantly different from the other adhesive materials (p<0.05). Leakage in enamel was lower than in cementum/dentin margins. It was concluded that bonded amalgam was an effective technique, since all materials prevented microleakage in enamel and cementum/dentin, when compared to the control group, except Panavia in cementum/dentin margins.

Animals↗

PubMed2004

One-year clinical evaluation of two polyacid-modified resin composites (compomers) in posterior permanent teeth.

PURPOSE: The aim of this study was to evaluate the clinical performance of two polyacid-modified resin composites (Dyract AP and F2000) in posterior teeth after 1 year of clinical service. MATERIALS AND METHODS: Seventy-two Class I restorations were performed in 33 patients (average age 25 years) by one operator. Eighty-two per cent of the restorations were located in molars. Before the proceedings, patients were informed about the aim of the study and they gave written consent to participate. At least one restoration of each material was placed in each individual. The materials were applied according manufacturer's instructions. Following finishing and polishing, one examiner performed the clinical baseline examination using the adapted USPHS system. To be included in the clinical trial, a restoration had to be rated "Alpha". After one year, 25 patients were recalled and 56 restorations were evaluated using the adapted USPHS system. RESULTS: All restorations were classified as clinically satisfactory (Alpha or Bravo). However, there was a decrease in restoration quality compared to baseline. Statistical analysis (chi2 and Fisher's exact test) demonstrated differences only in relation to superficial roughness, with exhibiting F2000 more surface roughness than Dyract AP (p < 0.01). CONCLUSION: Based on the methodology employed, all restorations were satisfactory after one year and the two materials performed similarly, except for the surface roughness criteria.

Acid Etching, Dental↗

PubMed2002

Dyes for caries detection: influence on composite and compomer microleakage.

The aim of this study was to evaluate the influence of caries-detecting dyes on the microleakage of adhesive materials. Sixty cubic class V cavities were prepared on buccal and lingual surfaces of 30 human third molars. Coronal margins were located in enamel and gingival margins in cementum. The teeth were randomly divided into six groups of ten restorations each. Cavities were restored with an adhesive system (Single Bond, 3M ESPE, St. Paul, Minn., USA), a compomer (F2000, 3M ESPE), or a composite resin (Z100, 3M ESPE) according to the manufacturer's directions. Acid red dye (Seek, Ultradent, South Jordan, Ut., USA) and basic fuchsin dye (Vide Cárie, Inodon, Porto Alegre, Brazil) were tested. Control groups were prepared without the use of dyes. After 7 days of storage in distilled water, the restorations were polished and the teeth were subjected to thermal cycling followed by immersion in 2% methylene blue. The teeth were sectioned, and microleakage scores were evaluated under magnification (40x). Data were submitted to statistical analysis using the nonparametric Kruskal-Wallis test. A statistically significant difference ( P<0.05) in microleakage was found between the materials in cementum (Z100>F2000) but not in enamel. Control and experimental groups using dyes showed similar results. It was concluded that dyes for caries detection did not increase microleakage of the adhesive materials tested.

Bisphenol A-Glycidyl Methacrylate↗

PubMedDate not supplied

Microleakage in conventional and bonded amalgam restorations: influence of cavity volume.

This study verified the relationship between the volume and microleakage of conventional and bonded amalgam restorations. Also, the microleakage influence of intermediate materials, substrates and the direction of sectioning was investigated. Fifty-six bovine incisors were selected. Standard Class V cavities were prepared in buccal and lingual surfaces. For each tooth, two cavity sizes were prepared, corresponding to two cavity volumes: one larger (A) and the other smaller (B). The cervical wall was located in cementum/dentin and the incisal wall in enamel. The teeth were distributed in four groups (n=28) according to the intermediate material employed (glass-ionomer cement, resin cement, adhesive system and copal varnish-control). The materials were applied following manufacturers' directions. After restoration, the teeth were submitted to thermal cycling. They were then immersed in a dye solution and sectioned in two directions inciso-cervical (IC) and mesio-distal (MD) sections to evaluate the microleakage. Data were subjected to non-parametric statistical analysis (Wilcoxon's paired test and Kruskal-Wallis test). No significant difference was found between the two cavity sizes. Leakage in enamel was statistically lower than in the cementum/dentin interface (p < 0.05). In some situations, glass-ionomer or resin cement lined amalgam restorations presented less dye leakage than copal varnish lined restorations (p < 0.05). No significant difference was observed in microleakage between IC or MD sectioning. Within the limitations of this study, it was concluded that cavity size and direction of section were not significant factors for microleakage, while substrate and intermediate materials had a significant effect on the sealing ability in amalgam restorations.

Animals↗