Effect of two Triphala formulations on resin–dentin bond strength and durability

Objective: This study aimed to evaluate the effect of two 0.2% Triphala (Phyllanthus emblica: Terminalia chebula: Terminalia bellirica) formulations: a standard 1:1:1 ratio and a modified 1:2:1 ratio with increased Terminalia chebula content, on immediate and six-month-aged microtensile bond strength (µTBS) of a composite resin.Methods: Twelve extracted caries-free molars were randomly assigned to three groups (n=4), based on the dentin pre-treatment applied after acid-etching: Group 1: control (no pre-treatment), Group 2: 0.2% Triphala 1:1:1, and Group 3: 0.2% Triphala 1:2:1. After applying the bonding agent, the teeth were restored with composite resin. Each tooth was sectioned to obtain multiple resin-dentin beams (1×1 mm), among which 24 were selected per group. In each group, 12 beams were tested after 24 hours, and 12 after 6 months of water storage at 37°C. µTBS was measured using a universal testing machine. Data were analyzed using ANOVA and independent t-tests (α = 0.05).Results: The control group exhibited a significant reduction in µTBS after 6 months (11.20±4.35 to 6.75±3.48 MPa; P=0.005). The Triphala-treated groups did not show a significant reduction in µTBS over time, with group 2 decreasing from 10.94±4.47 to 9.54±3.50 MPa (P=0.344) and group 3 from 11.06±5.95 to 10.50±8.35 MPa (P=0.866). Intergroup differences in bond strength were not significant at any time point (P>0.05).Conclusions: Dentin pre-treatment with 0.2% Triphala preserved µTBS over six months, suggesting potential MMP-inhibitory activity. Increasing the proportion of Terminalia chebula in the Triphala formulation from 1:1:1 to 1:2:1 did not provide additional benefits concerning bond durability.