Clinical minimally invasive treatments require the elimination of dental caries-infected tissues in order to stop the progression of bacteria to the pulpal chamber and maximise the reparative potential of the remaining partially demineralised tissues.
In order to encourage the remineralisation of the remaining partially demineralised dental tissues after caries removal, glass ionomer cements are currently used to favour the diffusion of the specific ions into mineral-depleted dentine. Nevertheless, these cements have no therapeutic ability to bio-remineralise the partially demineralised caries-affected dentine, accurately. It means that glass ionomer cements, along with most of the restorative materials currently used in minimally invasive dentistry, do not induce nucleation of new hydroxyapatite crystals within the demineralised dentine collagen at intra-fibrillar level.
Salvatore Sauro, Professor of Dental Biomaterials and Minimally Invasive Dentistry at CEU Cardenal Herrera University has led a research project which focused first on the use of phosphoproteins' biomimetic analogues in combination with experimental bioactive resin-based dental adhesives to remineralise the mineral-depleted dentine at the bonding interface of teeth filled with common restorative dental composites. The biomimetic analogues used in this study permitted the remineralisation of collagen fibrils through precipitation of hydroxyapatite at intra-fibrillar level, so that the biomechanical properties of the demineralised dentine, such as the elastic modulus and hardness were completely recovered. The results of this recent study have been published in Dental Materials, a journal ranking number one in the world's top dental journals.
According to professor Sauro, "the most important problem related to dental fillings in demineralised dental tissues, such as caries-affected dentine, is the lack of therapeutic bio-remineralisation which can extend the durability of the resin-dentine bonding interface created with dental adhesives and resin composites."
Biomimetic remineralisation
Professor Sauro and collaborators have also shown that by using analogues of phosphoproteins in combination with bioactive adhesive resin-based materials doped with calcium and phosphates, it is possible to improve the longevity of the adhesion of dental composite restorations to dental tissues due to the biomimetic remineralisation of mineral-depleted dentine at the bonding interface.
According to Salvatore Sauro, this study has demonstrated that the use of resin- adhesive doped with bioactive micro-fillers applied onto demineralised dentine pre-treated using biomimetic analogues of the phosphoproteins, such as polyaspartic acid (PLA) or sodium trimetaphosphate (TMP) represents an efficient and innovative therapeutic strategy to trigger biomimetic remineralisation processes at the bonding area between dentine and restorative materials. This result is a further step to the prolific research activity of Professor Sauro, who is currently focusing the energy of his entire group of research on the development of innovative bioactive and biomimetic restorative materials for therapeutic and aesthetic restorations of teeth affected by large caries lesions.