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Biomedical subjects

M A de Andrada

Publications and source records attributed to M A de Andrada.

9 recordsLinked to original sources
PubMed1998

The use of liners under amalgam restorations: an in vitro study on marginal leakage.

OBJECTIVE: Marginal leakage of amalgam restorations may lead to secondary caries and pulpal damage. The purpose of this study was to determine the effect various cavity liners might have on microleakage. METHOD AND MATERIALS: Mesio-occlusodistal amalgam restorations with margins on enamel and dentin were treated with different liner materials (an adhesive system, a topical fluoride gel, a cavity varnish, and a glass-ionomer cement) in vitro. Following restoration, the teeth were submitted to thermocycling in a stained solution and sectioned to allow assessment of microleakage. RESULTS: On enamel, the control group (no liner) and the glass-ionomer-lined group had equivalent leakage scores and were superior to every other group. On dentin, only the glass-ionomer specimens had superior performance. The cavity varnish and fluoride-lined specimens exhibited the highest leakage scores. CONCLUSION: The use of liners does not reduce microleakage on amalgam restorations when the cavity margins remain on enamel. On dentin margins, a glass-ionomer liner can reduce microleakage.

Adhesives↗
PubMed1994

Clinical evaluation of composite resin tunnel restorations on primary molars.

Twenty children, presenting 66 proximal carious lesions in 60 primary molars, were selected to receive composite resin tunnel restorations. Thirty of these teeth were expected to exfoliate within 6 months (group I); in the remaining 30 teeth exfoliation was expected within 1 year (group II). All teeth received tunnel preparations, which were then restored with a posterior composite resin. The restorations were evaluated after 6 months and after 1 year through each of the following methods: bitewing radiographic examination, clinical examination with a probe and mirror, and direct examination of proximal surfaces after tooth extraction. The occlusal portions of the restorations were considered to be excellent both after 6 months and 1 year. Radiographic examinations and direct examinations (performed after extraction of teeth) did not reveal the same percentages of secondary caries in the proximal portion of restorations. Fracture of the marginal crest reached 3% during the first 6 months, but fracture was absent during the subsequent 6 months.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1994

Reattachment of a tooth fragment with a "new" adhesive system: a case report.

A maxillary central incisor fractured, invading the biologic width. The biologic width was surgically restored, and in the same session the fragment was reattached to the tooth remnant with a "new" dentinal adhesive system. Short-term results indicate that esthetics, function, and oral health have been maintained.

Adult↗
PubMed1992

Amalgam repair: a case report.

Through the report of a clinical case, the feasibility and advantages of repair and recontouring of complex amalgam restorations are discussed. In this patient, the kind of alloy used for the fractured restoration and the age of the restoration were known factors. Additional mechanical retention was prepared in both the "old" amalgam and the dentin, and the repair was made with a high-copper alloy. The bond at the repair site was stable at the 2.5-year recall examination.

Adult↗
PubMed1992

Composite resin veneers: a new technique.

A new technique for the fabrication of composite resin direct veneers is presented. In this technique, a transparent acrylic resin matrix is fabricated before preparation of the facial surface of the tooth, to allow the adequate reproduction of contour, shape, and surface texture originally exhibited by the tooth. Advantages, as well as limitations, of the procedure are also presented.

Acrylic Resins↗
PubMedDate not supplied

An in vitro study of the effect of restorative technique on marginal leakage in posterior composites.

The purpose of this in vitro study was to compare marginal leakage of class 2 light-cured composite resin restorations, with different insertion and polymerization techniques. Fifty sound premolars extracted for prosthetic purposes were used in the study. Conservative class 2 (MOD) preparations were made in all teeth, with one proximogingival margin on enamel and the other on cementum. All the preparations and restorations were performed by the same operator utilizing the same restorative materials. After restoration the teeth were thermocycled and their gingival margins exposed to a dye. Results showed that the kind of matrix system had no significant influence upon the degree of marginal leakage on enamel. On cementum, oblique and horizontal incremental insertion and polymerization techniques using the collimator cone exhibited the least leakage, while the clear matrix band/reflective wedge technique presented the greatest leakage.

Bicuspid↗