Sleep Problems, Salivary Biomarkers, Dental Caries and Periodontal Status in School-Aged Children

Evaluation of the Relationship Between Sleep Disorders and Salivary Parameters With Dental Caries in School-Aged Children

Dental caries is one of the most prevalent chronic diseases in childhood. In addition to established etiological factors such as dietary habits and oral hygiene, biological and behavioral factors-including sleep disturbances and salivary biochemical characteristics-may contribute to caries development and periodontal health.

Saliva plays a critical role in maintaining oral homeostasis through its physical properties (flow rate, pH, and buffering capacity) and biochemical components. Salivary biomarkers such as melatonin, cortisol, interleukin-6 (IL-6) and oxidative stress parameters (total oxidant status [TOS], total antioxidant status [TAS], and oxidative stress index [OSI]) are associated with sleep regulation, stress response, inflammation and immune function.

This cross-sectional study aims to evaluate the relationship between sleep disturbances and salivary parameters as well as dental caries severity and periodontal status in children aged 6-12 years. A total of 73 children are categorized into two groups according to the International Caries Detection and Assessment System (ICDAS II): children with high-grade caries (codes 5-6) and children who are caries-free or have initial to moderate caries (codes 0-4).

All participants undergo a comprehensive oral examination to assess caries experience, plaque index, gingival index and bleeding on probing. Unstimulated saliva samples are collected to determine salivary flow rate, pH, buffering capacity, melatonin, cortisol, IL-6, TOS, TAS, and OSI levels. Sleep disturbances are evaluated using the Sleep Disturbance Scale for Children

Study Overview

• Status: Completed
• Conditions: Dental Caries; Sleep Problems; Periodontal Status

• Study Type: Observational
• Enrollment (Actual): 73

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Istanbul, Turkey (Türkiye)
    • Bezmialem Vakıf University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

A total of 73 healthy children aged 6-12 years (42 boys and 31 girls) were included in the study. The participants were divided into two groups: the study group (39 children with advanced dental caries, ICDAS II codes 5-6) and the control group (34 children who were caries-free or had initial-moderate caries, ICDAS II codes 0-4). Children with systemic diseases, conditions affecting salivary secretion, or recent use of medications influencing saliva were excluded. Written informed consent was obtained from the parents or legal guardians of all participants. Only children of Turkish ethnicty were included.

Description

Inclusion Criteria:

• Children aged 6-12 years
• Children with no systemic diseases

Exclusion Criteria:

• Children with systemic or local conditions affecting salivary secretion (diabetes, salivary gland infections, sialoliths, or neurological disorders)
• Children who had used medications affecting salivary secretion in the past three months (antimuscarinics, antihypertensives, or antidepressants)
• Children whose legal guardian did not provide written informed consent
• Children with the history of chemotheraphy or radiotherapy
• Children who are uncooperative with salivary sampling

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Study Group: Advanced Caries; Study Group (Advanced Caries): Children aged 6-12 years with advanced dental caries (ICDAS codes II 5-6). All participants were systemically healthy and of Turkish ethnicity.
Contol Group: Caries-Free / Mild-Moderate Caries; Control Group (Caries-Free / Mild-Moderate Caries): Children aged 6-12 years with no or mild-moderate dental caries (ICDAS II codes 0-4).All participants were systemically healthy and of Turkish ethnicity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Dental caries severity	Assessed using the International Caries Detection and Assessment System (ICDAS II, codes 0-6) for each primary and permanent tooth. Higher codes indicate more severe lesions. 0 = sound, 1 = first visual change in enamel, 2 = distinct visual change, 3 = localized enamel breakdown, 4 = underlying dark shadow, 5 = distinct cavity, 6 = extensive cavity.	One-time, baseline (July-September 2024
Cumulative caries experience	Assessed using the DMFT + dmft index to record the total number of decayed (D/d), missing (M/m) and filled (F/f) teeth in permanent and primary dentition.	One-time, baseline (July-September 2024)
Periodontal status - Plaque index	Plaque accumulation assessed on all teeth using the Silness-Löe plaque index (score 0-3). 0 = no plaque, 1 = slight plaque visible, 2 = moderate plaque, 3 = abundant plaque. Higher scores indicate more plaque accumulation.	One-time, baseline (July-September 2024)
Periodontal status - Gingival index	Gingival inflammation assessed on all teeth using the Silness-Löe gingival index (score range 0-3). Scores obtained from each tooth. Score interpretation: 0 = normal gingiva, 1 = mild inflammation (slight color change, no bleeding), 2 = moderate inflammation (redness, swelling, slight bleeding), 3 = severe inflammation (marked redness/swelling, bleeding on probing). Higher scores indicate more severe inflammation.	One-time, baseline (July-September 2024)
Periodontal status - Bleeding on Probing (BOP)	Bleeding on probing assessed on all teeth using the Ainamo & Bay index. Each site was gently probed; presence or absence of bleeding was recorded. Score interpretation: - = no bleeding, + = bleeding present. The percentage of bleeding sites relative to total sites was calculated per participant. Higher percentages indicate greater gingival inflammation.	One-time, baseline (July-September 2024)
Salivary flow rate	Measured in unstimulated saliva as mL/min; reflects saliva production rate. Higher values indicate greater salivary secretion	One-time, baseline (July-September 2024)
Salivary pH	Measured in unstimulated saliva using a digital pH meter; reported in pH units. Higher values indicate more alkaline saliva, lower values indicate more acidic saliva.	One-time, baseline (July-September 2024)
Salivary buffering capacity	Salivary buffering capacity measured using the Ericsson method, reflecting saliva's ability to neutralize acids and maintain pH homeostasis. Reported as a score/units; higher values indicate greater buffering capacity.	One-time, baseline (July-September 2024)
Salivary melatonin	Measured in unstimulated saliva using ELISA; reported in ng/mL. Melatonin is a hormone involved in sleep regulation and antioxidant defense. Higher values indicate higher melatonin levels.	One-time, baseline (July-September 2024)
Salivary cortisol	Measured in unstimulated saliva using ELISA; reported in ng/mL. Cortisol is a hormone related to stress response and sleep regulation. Higher values indicate higher cortisol levels.	One-time, baseline (July-September 2024)
Salivary IL-6	Measured in unstimulated saliva using ELISA; reported in pg/mL. IL-6 is a pro-inflammatory cytokine reflecting oral and systemic inflammation. Higher values indicate higher inflammatory status.	One-time, baseline (July-September 2024)
Total oxidant status (TOS)	Measured in unstimulated saliva spectrophotometrically; reported in mmol H2O2 equivalent/L. Reflects overall oxidative stress in saliva. Higher values indicate higher oxidant levels.	One-time, baseline (July-September 2024)
Total antioxidant status (TAS)	Measured in unstimulated saliva spectrophotometrically; reported in mmol Ascorbic acid equivalent/L. Reflects total antioxidant capacity of saliva. Higher values indicate greater antioxidant defense.	One-time, baseline (July-September 2024)
Oxidative stress index (OSI)	Calculated as the ratio of TOS to TAS; unitless. Reflects the balance between oxidants and antioxidants in saliva. Higher values indicate higher oxidative stress relative to antioxidant capacity.	One-time, baseline (July-September 2024)
Sleep disturbances	Assessed using the Sleep Disturbance Scale for Children (SDSC, total score ranging from 26 to 130) over the previous 6 months. Higher scores indicate greater risk or severity of sleep problems. A cutoff of 42 points is used; scores above this suggest an increased likelihood of sleep disturbances.	One-time, baseline (July-September 2024)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Child's toothbrushing frequency	Assessed via parent-completed questionnaire. Categories: "Once daily", "Twice daily", "Irregular".	One-time, baseline (July-September 2024)
Child's toothbrushing duration	Assessed via parent-completed questionnaire. Categories: "Less than 2 minutes", "2 minutes or more".	One-time, baseline (July-September 2024)
Parental assistance during toothbrushing	Assessed via parent-completed questionnaire. Categories: "Yes", "Sometimes", "No".	One-time, baseline (July-September 2024)
Regular dental floss use	Assessed via parent-completed questionnaire. Categories: "Yes", "Sometimes", "No".	One-time, baseline (July-September 2024)
Regular mouthwash use	Assessed via parent-completed questionnaire. Categories: "Yes", "Sometimes", "No".	One-time, baseline (July-September 2024)
Child's sex	Assessed via parent-completed questionnaire. Categories: "Male", "Female".	One-time, baseline (July-September 2024)
Father's education level	Assessed via parent-completed questionnaire. Categories: "Primary school", "High school", "University", "Master's degree".	One-time, baseline (July-September 2024)
Mother's education level	Assessed via parent-completed questionnaire. Categories: "Primary school", "High school", "University", "Master's degree".	One-time, baseline (July-September 2024)
Family monthly income	Assessed via parent-completed questionnaire. Categories: "Below minimum wage", "Up to 2x minimum wage", "Up to 3x minimum wage", "More than 3x minimum wage".	One-time, baseline (July-September 2024)

Collaborators and Investigators

• Sponsor: Bezmialem Vakif University

Study record dates

Study Major Dates

• Study Start (Actual): July 10, 2024
• Primary Completion (Actual): September 10, 2024
• Study Completion (Actual): September 30, 2024

Study Registration Dates

• First Submitted: February 5, 2026
• First Submitted That Met QC Criteria: February 16, 2026
• First Posted (Actual): February 23, 2026

Study Record Updates

• Last Update Posted (Actual): February 23, 2026
• Last Update Submitted That Met QC Criteria: February 16, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Stomatognathic Diseases; Nervous System Diseases; Mental Disorders; Tooth Diseases; Sleep Wake Disorders; Tooth Demineralization; Parasomnias; Dental Caries
• Other Study ID Numbers: 20240210

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No