Effect of Pulpotomy Agents on MTBS of Pulpal Primary Dentin

Objectives: The present study was undertaken to evaluate the effect of alternative hemostatic agents used for pulpotomy such as ferric sulfate and 5% NaOCl on microtensile bond strength (mTBS) of two adhesive systems to pulpal floor dentin of primary teeth in vitro.

Methods: Seventy-two extracted primary molars were included. Dentin specimens of the pulp chamber were obtained under standardized conditions. The specimens were randomly assigned to one of the six groups of twelve samples each: group PB-C: Prime&Bond, control group; PB-1: immersion for five minutes in ferric sulfate prior to bonding with Futurabond, PB-2: immersion for five minutes in 5% NaOCl prior to bonding; groups F-C, F-1 and F-2 followed the same procedure with Futurabond NR as adhesive. MTBS was measured 15 minutes after application of the corresponding compomer (Dyract/ Glasiosite) using an universal testing machine.

Results: Following mTBS were evaluated (mean values and standard deviations in MPa):

	PB-C	PB-1	PB-2	FB-C	FB-1	FB-2
Mean	20.3	16.4	14.2	10.5	14.1	14.3
+/-	3.6	5.6	2.7	3.7	2.8	3.0

Statistical analysis showed a significant influence of the used dentin adhesive and the hemostatic agent (p< 0.001, ANOVA). The immersion in 5% NaOCl before bonding procedure (PB-2, F-2) resulted in a significant reduction of mTBS compared to the untreated control groups (PB-C, F-C) (p< 0.05, Tukey´s test). Between the controls and ferric sulphate groups, significant differences could only be detected in the case of Futurabond NR (p< 0.05, Tukey´s test). Pairwise comparison between Prime&Bond and Futurabond showed no significant differences in all groups (p< 0.05, Tukey´s test).

Conclusions: Within the limitations of an in vitro investigation it can be concluded that hemostatic agents used for pulpotomy might have an adverse effect on mTBS of adhesive systems. In the case the self-etch adhesive Futurabond NR both hemostatic agents reduced mTBS.