Tooth decay is caused by two kinds of bacteria ​ — “mutans streptococci and lactobacilli ” — ​ that become a part of plaque, a sticky film of bacteria and food debris that forms on the teeth.
Hammaste lagunemist põhjustavad kaht liiki bakterid: Streptococcus mutans ja laktobatsill, mis moodustavad hambakatu – bakteritest ja toidujääkidest tekkinud kleepja kihi hammastel.