# The effect of soaking heat-polymerized acrylic resin denture base in avocado seed extract ( Persea americana Mill.) on the inhibition of denture-plaque microorganisms biofilm growth

## TL;DR

Soaking denture material in avocado seed extract can inhibit the growth of microorganisms that form biofilms on dentures.

## Contribution

This study is the first to investigate the effect of avocado seed extract on denture-plaque microorganism biofilm on acrylic resin.

## Key findings

- 20% avocado seed extract inhibited more than 50% of polymicrobial biofilm growth.
- Avocado seed extract showed significant inhibition of mono-species biofilms at concentrations as low as 5%.
- The extract was effective against multiple denture-related microorganisms including Candida and Staphylococcus.

## Abstract

Heat polymerized acrylic (HPA) resins are known to have high porosity that contributes to increased surface roughness and microcrack formation in stress areas. This facilitates the attachment and growth of polymicrobial biofilms contributing to increased antimicrobial resistance. Many research had been carried out on avocado seeds, but no research that studies the effect of avocado seeds on denture-plaque microorganism biofilm on HPA resin has been found.

This study used 144 samples (n=144), namely HPA resin discs covered with mono-species and polymicrobial biofilms consisting of
Candida albicans, Candida glabrata, Actinomyces odontolyticus,
Streptococcus gordonii, and
Staphylococcus aureus. The discs were soaked for 8 hours in the 5%, 10%, 15%, 20% avocado seed extract, positive control (alkaline peroxide), and negative control (aquadest). Each disc was shaken with a vortex mixer for 1 minute, and 100 μL was added into 96-well microplates with three times repetition and incubated for 24 hours. The inhibition values were determined from the percentage inhibition value formula which required absorption values from a microplate reader (595 nm).

In this research, it was found that the MBIC
50 of avocado seed extract against the mono-species of
C. albicans (5%),
C. glabrata (5%),
A. odontolyticus (15%),
S. gordonii (15%),
S. aureus (10%), while against the biofilm was 20%. There was a significant effect of soaking HPA resin in avocado seed extract of 5%, 10%, 15%, 20% on the inhibition of mono-species and polymicrobial biofilms of denture-plaque microorganisms with a value of p<0.001 (p<0.05).

The MBIC
50 of avocado seed extract in polymicrobial biofilm group was higher than that in the mono-species biofilm groups. Although alkaline peroxide showed higher inhibition value than that of the MBIC
50 in polymicrobial biofilm group, 20% avocado seed extract was effective in inhibiting polymicrobial biofilm because it was able to inhibit more than 50% polymicrobial biofilm.