Streptococcus mutans, sugar consumption, and oral hygiene: Which one has more effect on decayed, missing, and filled teeth (DMFT) score in Iranian adults?

Abstract

Background: Streptococcus mutans as an acid‑generator of biofilm, sugar as a caries‑conducive
environment, and oral hygiene have been implicated as major etiological agents in dental caries.
 This study was designed to assess the association and impact of S. mutans, sugar consumption,
and tooth brushing on decayed, missing, and filled teeth (DMFT) score in Iranian 20–30‑year‑old
individuals and compare the effect of the three mentioned factors to find the most effective one.
Materials and Methods: In this cross‑sectional study, 459 adults completed a Sugar Frequency
Questionnaire and were examined for dental caries using DMFT index, sugar consumption level,
and tooth brushing frequency per day. Saliva and plaque samples were collected, and the target
population without Streptococcus sobrinus in their microbial oral community was selected using
polymerase chain reaction technique. Data were analyzed by one‑way analysis of variance and multiple linear regression tests (α = 0.05).

Results: Nearly 77.1% of the study population were harboring S. mutans. Mean DMFT of the
population was 6.62. Mean comparison analysis showed that there is a strong relationship between
S. mutans existence in mouth flora and DMFT scores (P < 0.0001). Multiple linear regression test
showed higher percentage of S. mutans contribution (28.2%) in DMFT score changes than sugar
consumption (3.6%) and tooth brushing (0.7%).
Conclusions: This study provides a recent report from S. mutans frequency and DMFT score in
Iranian adult population. It is also the first study that shows significantly higher impact of S. mutans
in microbial population of mouth microflora on caries development than sugar consumption and oral hygiene. Accordingly, S. mutans screening program should be more highlighted in preventive
strategies.