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Biomedical subjects

R L Macchi

Publications and source records attributed to R L Macchi.

At least 19 recordsLinked to original sources
PubMed1992

Influence of endodontic materials on the bonding of composite resin to dentin.

We assessed the bond strength of a composite resin to dentin that had been in contact with different materials. Flat dentin surfaces in freshly extracted human teeth were covered for 15 min or 48 h with a 1-mm layer of a variety of materials. The products were mechanically removed and a composite resin cylindrical specimen bonded to the dentin surface using the Prisma universal bond system. After 7 days immersion at 37 degrees C in water, the tensile bond strength was tested. The results were compared with those on dentin surfaces not in contact with any endodontic material. Statistical analysis showed that some materials (Grossmans Cement, IRM, Maisto's slowly resorbable paste) reduced the strength of the bond or even precluded bonding. It is necessary to develop techniques that will eliminate this when restoring endodontically treated teeth.

Adhesiveness↗
PubMed1988

Modern restorative dentistry: a new approach.

An analysis of the role of restorative dentistry within oral health care shows that it has broadened its scope over its long history. It started with the replacement of lost teeth and, later, lesions and structural defects of tooth tissue were treated. Progress has been achieved through the development of new materials and procedures, specifically those that ensure microscopic and/or chemical adhesion and those that allow for the removal of infection tissue and its restoration, while protecting the remaining healthy structure of the tooth. Teeth can also be protected even before the initiation of an infected lesion by sealing morphologic features such as pits and fissures. All of these procedures are components of modern restorative dentistry which now contributes to the disappearance of the totally edentulous patient. Dentistry has the responsibility of helping in the generation of sufficient social and economic resource to make this modern restorative dentistry available to the community as a whole.

Dental Bonding↗
PubMed1977

Enamel surface treated with zinc polyacrylate dental cement.

The surface of tooth enamel that had been left in touch with the liquid or the mix of a zinc polyacrylate dental cement was studied by scanning electron microscopy. Both treatments produced lesions on the enamel and were represented by unevenly distributed microcavities of varying extension. Topically applied SnF2 did not modify the aspect of the treated surface.

Acid Etching, Dental↗
PubMed1974

[Composites].

Explore the source record for details and available documents.

Composite Resins↗
PubMedDate not supplied

Enamel corrosion produced by zinc phosphate dental cement.

The application of a phosphoric acid solution or of a zinc phosphate cement mix on enamel surface causes alteration of its structure. The lesions of the enamel are cavities of irregular shapes that might retain debris. In view of the high solubility of disintegration of the cement, those cavities can be considered potential sites of plaque installation and initiation of carious processes.

Corrosion↗
PubMedDate not supplied

[Varnishes and adhesives in the seal of silver amalgam restorations].

The object of this paper is to evaluate the marginal filtration occurring between restoration/teeth in cavities filled with silver alloy when using different cavity varnish and adhesives. In 50 teeth removed as a result of decay, cavities were prepaired on vestibular faces and were divided into 5 equal groups: Group A: with no caviti varnish; Group B: two coats of a linkin agent (Scotch Bond 3M); Group C: an amalgam liner base (Voco); Group D; two coats of copal varnish: Group E: an amalgam bond base (Carl San Remo, Germany). All groups were filled with a silver alloy. The teeth were inmersed in a fuchsin solution at different temperatures (17.37 degrees C and 50 degrees C) for 20 minutes. Longitudinal cuts were made for visualization under a stereoscopic magnifying glass. Each group was observed by five odontologists and was classified according to four categories: Grade I: no filtration: Grade II: less than 1/3 wall filtration; Grade III: more than 1/3 wall filtration; Grade IV: filtration in walls and floor. Teeth with pulp filtration were discarded. Total and percentage values were determined for each analysed group. The results revealed that: Group A: 100% of samples corresponds to Grade IV. Group B: 40% of sample falls within Grade II while the rest corresponds to the highest grade. Group C: 30% belongs to Grade II, 60% to Grade III and the remaining 10% to Grade IV; Group D: 30% falls within Grade I, while the remaining 20% and 50% correspond to Grades III and IV, respectively. Group E: 50% for Grade I and the rest in Grade II.(ABSTRACT TRUNCATED AT 250 WORDS)

Adhesives↗