Microplastic chip occurrence at toothbrush bristle tips:an optical microscopy investigation / 대한구강보건학회지

ABSTRACT

Objectives@#This study aimed to investigate the presence of microplastic chips at the tips of toothbrush bristles using optical microscopy. @*Methods@#Toothbrushes available in South Korea were tested. We randomly selected 12 toothbrushes, including four domestically produced and eight imported toothbrushes. Toothbrushes with tapered bristle ends were excluded. Toothbrushes with conventional bristle shapes based on visual inspection were included. Three identical toothbrushes were prepared. The outer bristles of each toothbrush were sampled using ScotchTM tape and prepared using a scalpel for optical microscopy.The inspector visually assessed both the bristle diameter and the presence of microplastic chips that remained attached to the ends of the toothbrush bristles under light microscopy (40× magnification). @*Results@#All toothbrush bristles met the criteria for soft bristles (diameters ranging from 0.2 to 0.25 mm). The incidence of microplastic chips varied among toothbrush bristles, ranging from a minimum of 3.6% to a maximum of 86.2%. Notably, toothbrushes with smaller diameter bristles exhibited higher levels of microplastic chips. @*Conclusions@#This study confirmed that the trimming conditions of toothbrush bristles and the occurrence of microplastic chips vary among different toothbrushes. Our findings suggest that toothbrush manufacturers need to improve their manufacturing processes to prevent the generation of microplastic chips during bristle trimming.