Title: 0841 - Polymerisation and Dentine Penetration of A Novel Self-sealing Composite
Zoi Tzelepi (Presenter)
Eastman Dental Institute
Paul Ashley, UCL Eastman Dental Institute
Anne Young, UCL Eastman Institute
Objectives: The aim of this project was to assess if a new composite, designed for restoring primary molars, has sufficient monomer conversion for single step bulk placement and can form resin tags into carious versus affected dentine.
Methods: The new composite monomer conversions (MC) at depths of 2mm with 20s versus 4mm with 40s light exposure were determined using ATR FTIR. A commercial composite (Z250, 3M) and a resin modified glass ionomer cement (Fuji II-LC, GC) were used as controls (n=3).
To assess resin tag formation, 12 carious primary molars were excavated to give two groups with either minimal or partial caries removal. For each group, three teeth were filled with the new composite and three with Fuji II LC. Following embedding in self-curing resin blocks, the dentine / material interfaces were exposed through sectioning and examined qualitatively using Light, Confocal and Scanning Electron Microscopies.
Results: For the new formulation 75% and 70% monomer conversion was obtained at 2 and 4mm depth respectively. For Z250, results were 56% and 53% and for Fuji II-LC 90% and 93% respectively.
For the experimental but not commercial material, resin tag formation up to 200 micron in length was observed in both highly infected dentine and the underlying disease affected dentine by the various microscopic techniques.
Conclusions: The new composite had better monomer conversion than a commercial composite at both 2 and 4mm depth suggesting it may be placed in a single step without layering. The RMGIC had much higher levels of conversion but this is required due to the presence of mono instead of dimethacrylate monomers. Resin tag formation with the new composite suggests good sealing may be feasible without need for any adhesive.
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: "NONE"