Preparation and properties of calcium-silicate filled resins for dental restoration. Part II: Micro-mechanical behaviour to primed mineral-depleted dentine.
OBJECTIVE
Evaluating microtensile bond strength (μTBS) and Knoop micro-hardness (KHN) of resin bonded-dentine interfaces created with two methacrylate-based systems either incorporating Bioglass 45S5 (3-E&RA/BG) or MTA (3-E&RA/WMTA).


METHODS
Solvated resins (50% ethanol/50% co-monomers) were used as primers while their neat counterparts were filled with the two calcium-silicate compounds. Application of neat resin adhesive with no filler served as control (3-E&RA). μTBS, KHN analysis and confocal tandem scanning microscopy (TSM) micropermeability were carried out after 24 h and 10 months of storage in phosphate buffer solution (DPBS). Scanning electron microscopy (SEM) was also performed after debonding.


RESULTS
High μTBS values were achieved in all groups after 24 h of DPBS storage. On the contrary, solely the specimens created using 3-E&RA/BG and 3-E&RA/WMTA agents showed no significant reduction in terms of μTBS even after 10 months in DPBS; similarly, they did not restore the average superficial micro-hardness to the level of sound dentine, but maintained unchanged KHN values, and no statistical decrease was found following 10 months of DPBS storage. The only statistically significant changes occurred in the resin-dentine interfaces bonded with 3-E&RA that were subjected to a reduction of both μTBS and KHN values with ageing. In terms of micropermeability, adverse results were obtained with 3-E&RA while 3-E&RA/BG and 3-E&RA/WMTA demonstrated a beneficial effect after prolonged DPBS storage.


CONCLUSIONS
Calcium-silicate filled composite resins performed better than a current etch-and-rinse adhesive and had a therapeutic/protective effect on the micro-mechanical properties of mineral-depleted resin-dentine interfaces.


CONCLUSIONS
The incorporation of calcium-silicates into dental restorative and bonding agents can create more biomimetic (life-like) restorations. This will not only enable these materials to mimic the physical characteristics of the tooth structure, but will also stabilize and protect the remaining dental hard tissues.
Department of Restorative Dentistry, Biomaterials Science, Biomimetics and Biophotonics (B3) Research Group, King's College London Dental Institute, Guy's Dental Hospital , London , UK.
Andrea Corrado
AC
Profeta
D000328:Adult; D017607:Aluminum Compounds / Q000737:chemistry*; D001031:Apatites / Q000737:chemistry*; D001565:Benzoates / Q000737:chemistry; D001696:Biomechanical Phenomena; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003804:Dentin / Q000737:chemistry / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D004338:Drug Combinations; D005898:Glass / Q000737:chemistry*; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D010087:Oxides / Q000737:chemistry*; D010539:Permeability; D019279:Resin Cements / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D055815:Young Adult
D017607:Aluminum Compounds; D001031:Apatites; D001565:Benzoates; D017610:Calcium Compounds; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D004338:Drug Combinations; C444701:Filtek Z250; D008689:Methacrylates; D010087:Oxides; D019279:Resin Cements; D017640:Silicates; C425330:bioactive glass 45S5; C086631:mineral trioxide aggregate; C043042:pyromellitic acid dianhydride-2-hydroxyethyl methacrylate adduct; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate; C031293:calcium silicate
Bioglass® 45S5; biomechanical properties; etch-and-rinse systems; mineral trioxide aggregate; resin bonded-dentine interface