Quantification Of Factors Affecting Composite Bonding To Ivory Dentine

Quantification Of Factors Affecting Composite Bonding To Ivory Dentine

Objectives:

Assessment of how replacement of the activator DMPT by the adhesive activator SAN, and TEGDMA diluent with higher molecular weight PPGDMA in dental composites, affects dentine adhesion.

Methods:

Base monomer UDMA and diluent monomers TEGDMA (T) or PPGDMA (P) in 3:1 mass ratio were mixed with 5 wt % HEMA, 1wt% CQ and 1wt% DMPT (D) or SAN (N) to provide 4 composites designated as TD, TN, PD and PN. These were combined with silane treated glass particles. PLR was 4:1. The commercial composite Z250 was used as control.

Ivory dentine blocks 5mm deep were used as received or after hydration / dehydration at 37C.  Cylindrical holes (3mm diameter) were drilled and treated with 37 % phosphoric acid gel, and / or ibond total etch for 20s prior to filing with the composites. The debonding force (kN) required to push out the composite cylinders was determined (Table 1).

Results:

The greatest debonding forces (kN) observed were with ibond use irrespective of other ivory treatment.  All experimental materials had greater bonding than Z250 when ibond was used.  With no ibond, increasing dentine water content and acid treatment increased bonding.  Under most conditions formulations containing both SAN and PPGDMA gave higher bonding.

Conclusions:

SAN and PPGDMA improves composite dentine bonding.

Table 1.  Debonding forces (kN) for composite cylinders in ivory dentine.