How Periodontal Disease Compromises Oral Functions Related to Ingestion: Evidence From Systematic Review and...

Evidence on how periodontitis affects oral function related to ingestion remains limited. Understanding these functional consequences is important for incorporating function-focused care into periodontal practice and for improving oral health and quality of life. This review examined whether periodontal disease is associated with impairments of oral functions and whether periodontal therapy may improve these functions.

This systematic review followed PRISMA 2020 guidelines and was registered in PROSPERO (CRD42024619735). A systematic search of PubMed and Cochrane Library was conducted for studies published between January 2010 and December 2024. Of 4004 records screened, 47 met the inclusion criteria. The included studies comprised 28 cross-sectional studies, 18 prospective clinical studies, and one longitudinal observational study. Risk of bias was assessed using RoB 2 for randomised controlled trials, ROBINS-I for non-randomised interventional studies, and ROBINS-E for studies evaluating exposure effects. Data were synthesised using qualitative and quantitative approaches.

The oral functions assessed were salivary function, mastication, biting, and self-reported oral functional outcomes. Most studies reported reduced salivary flow, bite force, and masticatory performance in individuals with periodontitis, while many prospective studies described functional improvement after periodontal therapy. Meta-analyses showed that individuals with periodontitis had significantly lower salivary flow (Hedges' g = -1.14, p < 0.001) and higher eating-related disability scores (Hedges' g = 0.45, p < 0.001) than healthy controls. Periodontal therapy was associated with a significant increase in salivary flow (Hedges' g = 0.41, p = 0.043). An exploratory meta-analysis also suggested a reduction in eating-related disability after treatment (Hedges' g = -0.34, p = 0.005), although this finding should be interpreted cautiously because the pooled studies included different interventional designs. Evidence regarding swallowing-related outcomes was extremely limited, with only two studies assessing this domain and neither demonstrating a significant association with periodontal disease.

Periodontal disease appears to be associated with impaired oral function, particularly mastication, biting, salivary function, and chewing-related quality-of-life outcomes. Periodontal therapy may contribute to partial functional improvement in some of these domains. Periodontal care should therefore consider not only disease control but also preservation and improvement of oral function. Future research should prioritise longitudinal and well-designed interventional studies to clarify causal relationships and quantify functional recovery after periodontal therapy.