Biomedical subjects

A A Suliman

Publications and source records attributed to A A Suliman.

4 recordsLinked to original sources

PubMed1993

Cusp movement in premolars resulting from composite polymerization shrinkage.

This study examined the effect of cavity size, hydration conditions and type of composite on cusp movement following placement of MOD composite restorations in vitro. A microscope with a micrometer stage was used to measure deflection of cusps for 14 days after initiation of curing. The intercuspal width decreased for the first few minutes after the composites were placed, then increased toward the original dimensions. Teeth with small cavities contracted less than those with large cavities, and recovery was complete or nearly complete only in teeth with small cavities. Hydrated teeth and restorations recovered more rapidly and more completely than those that were dry. Differences in deflection of the cusps were observed with two different restorative materials.

Absorption↗

PubMed1993

Interferometric measurements of cusp deformation of teeth restored with composites.

A Michelson interferometry apparatus was used for measurement of the displacement of the buccal cusps of premolars after restoration of MOD preparations with composites. The effects of composite type, cavity size, and hydration conditions were examined. Interferometry permitted real-time measurement of cusp movement as it occurred. Contraction occurred very rapidly, about 1/3 of the 60-minute amount within the two-minute period of exposure to the curing light. Cusp movement was smooth rather than interrupted, indicating lack of microfracturing at deformations of 11-46 microns. Contraction, 0.94% for Heliomolar and 1.2% for P-50, was similar to the linear polymerization shrinkage of the resins. Less cusp movement occurred in small cavities than in large cavities. Hydrated teeth had less cusp movement than dehydrated teeth.

Acid Etching, Dental↗

PubMed1992

Microleakage between different types of base materials.

This study investigated the sealing properties of various combinations of base materials. Three chemically cured and three light-activated base materials were combinationally used to make 15 sample groups. The samples were thermocycled and immersed in 0.05% crystal violet solution for 1 hour. They were then embedded in clear casting resin, sectioned, and photographed. The interfaces of the samples were digitized. The ratio of the total interface length to the penetration of leakage was calculated and compared. The results indicated that the combination of Cavalite and VLC Dycal materials had the least microleakage and was significantly different from the other 14 groups.

Acrylic Resins↗

PubMed1989

Effects of etching and rinsing times and salivary contamination on etched glass-ionomer cement bonded to resin composites.

This study investigated the effect of salivary contamination on glass-ionomer/resin-composite bond strength after establishment of an appropriate etching and rinsing time for the glass-ionomer cement. Three hundred and thirty samples of glass-ionomer cement (Ketac-Fil) were injected into cavities prepared in acrylic molds. Groups containing 15 samples each were etched for 0, 15, 30, or 60 sec, after which Scotchbond and either Silux or P-30 were applied and polymerized. The samples were stored under water for 24 hr at 37 degrees C and were then tested in shear. A 30-second etching time was found to be optimal when Silux and P-30 were considered together. In a similar manner, a 20-second optimal rinsing time was determined. Samples of glass-ionomer cement were then contaminated with saliva, dried, and bonded to composite resins and tested in shear as before. Significantly lower bond strengths resulted than with the uncontaminated controls. Efforts to clean contaminated samples by rinsing or re-etching failed to increase the bond strength obtained with the contaminated samples.

Acid Etching, Dental↗