Adhesion between living tissue and plastics. I. Adhesion of epoxy and polyurethane resins to dentin and enamel

A comparison between three different pit and fissure sealants with regard to marginal integrity

AIM

THE AIM OF THIS STUDY IS TO COMPARE THE OCCURRENCE OF ENAMEL FRACTURES, SEALANT FRACTURES AND MARGINAL FISSURES AFTER PLACEMENT OF THREE SEALANTS: Helioseal F, Conseal F and Clinpro.

MATERIALS AND METHODS

Thirty individuals between 13 and 15 years of age, diagnosed with pit and fissure caries by visual and DIAGNOdent examination, were chosen for sealant placement on their mandibular molars. The sealants were placed at random, after which, impressions were made with polyvinyl siloxane and casts were fabricated. Dies were prepared, each of which were sputter coated with gold in order to be examined under a scanning electron microscope. The following morphologies were analyzed from dies from each of the sealant groups: Continuous margins, sealant fractures, marginal fissures and enamel fractures. After six months, they were recalled for impression making. Dies were prepared and microscopically analyzed as mentioned. Based on the time of evaluation, there were two groups: Initial group (soon after placement) and final group (after six months). Statistical analysis was done using the paired 't' test and One-way analysis of variance (ANOVA).

RESULTS AND CONCLUSIONS

Clinpro had the greatest fracture resistance, followed by Conseal F and Helioseal F. The occurrence of marginal fissure was found to be least with Clinpro.

Isocyanato urethane methacrylates derived from hydroxyethyl methacrylate

Isocyanato urethane methacrylates were synthesized from five diisocyanates and hydroxyethyl methacrylate. They may be homopolymerized or copolymerized with other methacrylates by the usual free radical methods of initiation and have potential as adhesion-promoting agents for dentin.

Effects of adhesion promoters on resin-enamel retention

The adhesive effects of three adhesion promoters were compared utilizing three different filled resins on acid-etched human permanent teeth. The results demonstrated a significantly greater resistance to dislodgement of resins by shear forces when an NPG-GMA type of adhesion promoter was utilized. Type of resin did not influence resin retention.

Adhesion of synthetic organic polymer to soft tissue. III. Effect of some monofunctional compounds

Previous work in this series has shown that some aromatic and n-alkyl isocynates can significantly improve the adhesion of a fast-setting polyurethane prepolymer to internal tissue. In the present study, several acyl or aroyl anhydrides, chlorides, and a triaryl chloroalkane have been found to effect various degrees of improvement in the adhesion of fast-setting prepolymer to tissue. To determine the influence of minor structural changes on adhesion, the isomers of methyl phenyl isocynate and chlorobenzoyl chloride were investigated. The isomers were found to give the same extent of improvement in adhesion of the prepolymer as the parent compound without the methyl or chloro substituents. Among all the reactive monofunctional compounds studied, benzoyl chloride and its chlorobenzoyl derivatives are the most effective. When primed on tissue or admixed as little as a 3% additive in some polymer preparations, these aroyl chlorides can promote the adhesion of many ordinary adhesives to internal tissue. The effectiveness is attributed to the modification of hydrophilic tissue surface by the hydrophobic benzoyl group attached to tissue after reaction. The prosthetic benzoyl group makes the tissue/polymer interface more compatible and the compatibility results in good adhesion.