Salivary Markers and Microbial Flora in Mouth Breathing Late Adolescents

This is a 6-month observational case-control study that aims to estimate plaque index (PI), salivary flow, buffering capacity of saliva, and specific Streptococcus mutans (S. mutans) and Lactobacillus rates in a mouth breathing late adolescents sample, after a professional oral hygiene procedure and home oral hygiene instructions.

A sample of 20 mouth breathing late adolescents/young adults (average: 19.2 ± 2.5; range: 18-23 years) and a matched control group of nose breathing subjects (average: 18.3 ± 3.2; range 18-23 years) were included in the study. All the participants were subjected to a professional oral hygiene procedure and appropriate home oral hygiene instructions (t0). After three months (t1) and six months (t2), the PI, salivary flow, buffering capacity of saliva, and S. mutans and Lactobacilli rates were recorded.

The mean buffering capacity of saliva and the salivary flow rate showed no significant difference between the two groups, all over the observational period. For PI, a significantly higher mode (score 1 of PI) was observed in the study group at t1 (score 0 = 35% of subjects; score 1 = 60%; score 2 = 5%) and t2 (score 1 = 65% of subjects, score 2 = 35%), with respect to control group. Furthermore, mouth breathing subjects show a significant 4 times higher risk to develop S. mutans CFU > 10⁵ (CI lower limit: 0.95; CI upper limit: 9.48; chi-square: 4.28; p = 0.03), with respect to the control subjects.

Mouth breathing late adolescents show a significantly higher risk to develop S. mutans CFU > 10⁵ and an increased level of PI. Interceptive orthodontic treatments in growing subjects, like palatal expansion, are encouraged to improve the nasal air flow. In older subjects, orthodontic treatments should be performed with removable appliances like clear aligners, in order to allow a better oral hygiene level.