Association between sleep pattern, salivary cariogenic bacteria and fungi populations, pH and buffering capacity in children: A comparative study.

Background: Sleep quality has a significant impact on a child's health and is linked to oral and systemic diseases. It affects the circadian rhythm, which plays a crucial role in regulating the balance of the endocrine and hormonal systems. Current research has focused on exploring its role in the development of caries, which is influenced by inherent oral factors such as the composition of the oral microbiome and pH levels.

Objectives: This study aimed to investigate the relationship between bacterial population, pH, and buffering properties of saliva and sleep patterns in 8- to 12-year-old children.

Material and methods: This cross-sectional study was conducted on 85 elementary school children aged 8-12 years. After obtaining written consent, non-stimulating saliva samples were collected using the spitting method. The participants' sleep pattern information was obtained with the use of the Persian version of the Children's Sleep Habits Questionnaire (CSHQ). Based on the results of the CSHQ, the participants were divided into 2 groups: those with appropriate sleep patterns; and those with inappropriate sleep patterns. The study compared the bacterial population of Streptococcus mutans, Lactobacillus spp. and Candida albicans, as well as the buffering capacity and pH of the saliva between the 2 groups. The statistical analysis employed the χ2 test, the independent samples t-test and Spearman's correlation.

Results: The group with inappropriate sleep patterns had significantly lower pH and buffering capacity (p < 0.001) and significantly higher colony counts of Lactobacillus and S. mutans (p < 0.001 and p = 0.012, respectively). There was no association between C. albicans and sleep patterns (p = 0.121).

Conclusions: Inappropriate sleep patterns increase the population of caries-causing bacteria and reduce salivary pH and buffering capacity. This can be a significant factor in the development of dental caries in children aged 8-12 years.