Biomedical subjects
Publications and source records attributed to A M Flood.
Guidelines for the successful use of resin bonded bridges are presented. The importance of sound case selection cannot be overemphasized. Other factors that influence the clinical success of resin bonded bridges include preparation design, choice of metal, surface preparation of metal, and the need to respect the sensitivity of the etched alloy surface of the Maryland bridge before and at the cementation stage.
The tensile bond strengths of three groups of adhesives to two electrolytically etched alloys were studied. It was found that the bis-GMA composite resins gave statistically similar bond strengths. The newer Japanese acrylics tested gave statistically higher results than the bis-GMA resins. The clinical significance of these results is discussed.
Posts are normally used to aid core retention and to provide tooth support, although a significant minority question the use of posts in the latter role. A direct relationship is thought to exist between the quantity of sound tooth structure and tooth strength and care is required when preparing teeth to accept posts. Post configuration is of over-riding importance in determining retention and support and the effect on retention of small increases to post length should not be over emphasized. Because accurate post fit is important to maximize both retention and support, direct fabrication techniques using matched post/reamer systems are recommended.
The functions and features of cores in restorative dentistry and the importance of preserving sound tooth tissue are discussed. The experimental and clinical support for a perceived superiority of cast post cores is reviewed. It is suggested that there is a need to re-evaluate this viewpoint, particularly when restoring posterior teeth. The materials currently in use are briefly discussed as well as research relating to possible core/luting agent interactions.
This study examined the interface between composite resin and two electrolytically etched alloys using different etching times. A new technique allowed this interface to be tested under both tensile and shear loading. The resultant surface morphology of the etched metal was also examined. There was a very large difference in the bond strengths and surface morphologies between the alloys. The bond strength results indicate the sensitivity of this interface to alterations in etching time, and this is also shown in the resultant surface morphology. The clinical significance of these findings is discussed and clinical recommendations made.