IMPACT OF DIFFERENT CONCENTRATIONS OF SALVIA OFFICINALIS ON THE FLEXURAL STRENGTH AND MICROHARDNESS OF RESIN-MODIFIED GLASS-IONOMER CEMENTS

Abstract

Resin modified glass-ionomer cement (RMGIC) has become popular in restorative dentistry due to its adhesive properties to dental hard tissues, fluoride release and ease of handling when compared with conventional glass-ionomer cement. However, flexural strength and the surface hardness and mechanical durability over time are still points of concern. Sage (Salvia officinalis) is rich in phenolic compounds, flavonoids and essential oil constituents that have been reported to have antioxidant, antimicrobial and anti-inflammatory properties. The inclusion in RMGIC might offer a way to bioactive restorative materials, without losing mechanical properties. The objective of this thesis was to check the flexural strength and microhardness changes of RMGIC after adding Salvia officinalis powder with different concentrations. The methods used were by comparing a control RMGIC group with RMGIC with 2%, 5% and 7% Salvia officinalis powder by weight. There were 100 valid flexural strength samples provided in the sample collection: 25 samples in each group. The flexural strength was determined by three-point bending test using the equation sigma = 3FL / 2bh2, where F is fracture load, L is supporting span, b is width and h is thickness. Descriptive statistics were used to analyse the data, followed by the Shapiro-Wilk normality test, Levene's test for homogeneity, one-way ANOVA, followed by Kruskal-Walli’s sensitivity testing and pairwise comparisons. Available bench-note readings and specimen images were used to describe microhardness. Mean flexural strength was 10.15 MPa for control, 10.44 MPa for 2% sage, 10.43 MPa for 5% sage and 10.32 MPa for 7% sage. Normality and homogeneity were met. There was no significant difference between the groups based on one-way ANOVA (p = 0.732). This was corroborated by Kruskal-Walli’s testing (p = 0.720). The available microhardness readings were descriptive and incomplete and thus, there was no definitive conclusion regarding the microhardness. Discussion: Salvia officinalis powder with the concentration of 2%, 5% and 7% was not significantly reduce flexural strength of RMGIC. Mechanically, the modified groups were similar to the control group in bending. Prior to clinical interpretation, complete microhardness data and antibacterial testing is recommended.

Keywords: Resin-modified glass-ionomer cement; Salvia officinalis; sage; flexural strength; microhardness; dental materials.