Evaluation of salivary pH in pediatric patients undergoing orthodontic treatment with rapid palatal expander: cross-sectional study

Background: Orthodontic appliances increase the difficulty of maintaining oral hygiene due to their size and complexity. This study aimed to evaluate salivary pH and buffer capacity in pediatric patients aged 6–14 years using the Saliva-Check Buffer test comparing two groups: patients who have completed dental treatments but have not yet started the orthodontic treatment (control group), and those who have been undergoing orthodontic treatment with rapid palatal expander (RPE) for at least six months (trial group). Methods: Clinical assessments included the recording of Decayed, Missing, Filled Teeth (DMFT + dmft), Decayed, Missing, Filled Surfaces (DMFS + dmfs), plaque control record (PCR) and Frankl behavioural scale. Salivary pH and buffering capacity were measured using the Saliva-Check Buffer kit which consisted of five different tests. Data were statistically analyzed, assessing data normality of distributions with Kolmogorov-Smirnov test, and subsequently performing Mann-Whitney test and linear regressions analyses (significance threshold: p < 0.05). Results: Orthodontic patients exhibited significantly higher PCR scores and lower salivary buffering capacity compared to the pre-orthodontic group (p < 0.05). No significant differences were observed in DMFT + dmft and DMFS + dmfs scores between the groups (p > 0.05), but DMFS + dmfs significantly influenced salivary consistency, pH and buffering capacity (p < 0.05). Salivary consistency significantly influenced by age, while salivary pH seemed influenced by PCR and group. Sex and group significantly influenced saliva quantity (p < 0.05), and finally PCR significantly influenced salivary buffering capacity (p < 0.05). Conclusions: The findings suggest that orthodontic treatment may contribute to increased plaque accumulation and reduced salivary buffering capacity, potentially elevating caries risk. Enhanced oral hygiene measures and preventive strategies are recommended for orthodontic patients. Clinical Trial Registration: the study was registered on clinicaltrials.gov (NCT06922799).

Dental caries; Pediatric dentistry; Orthodontic appliances; Interceptive orthodontics; Salivary pH

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