Neurology · Medical Literature
Dental Caries Experience in Older Adults With Parkinson's Disease: A Systematic Review and Meta-Analysis.
Abstract
This systematic review and meta-analysis assessed whether individuals with Parkinson's disease (PD) have higher dental caries rates than those without PD. Seven electronic databases and gray literature sources were systematically searched for observational studies comparing dental caries between individuals with and without PD. Risk of bias was assessed using the Newcastle-Ottawa Scale. Meta-analyses of continuous data were performed, reporting mean differences (MD) with 95% confidence intervals (CI). The strength of evidence was appraised using the GRADE framework. Of 389 retrieved records, 10 studies were included, comprising 1726 individuals (573 with PD; 1153 controls). All studies employed a cross-sectional design with a control group and exhibited a moderate risk of bias. Meta-analyses revealed no significant differences in the decayed, missing, and filled teeth (DMFT) index (k = 5) (MD = -0.30; 95% CI = -5.18-4.57) or untreated dental caries (k = 4) (MD = 0.73; 95% CI = -1.66-3.12). The strength of evidence was classified as low. To date, very-low-certainty evidence does not demonstrate a statistically significant difference in dental caries experience between older adults with and without PD. These findings should be interpreted cautiously and should not be taken as evidence that PD is unrelated to current or future dental caries susceptibility.
Clinical relevance
Do older adults with Parkinson's disease (PD) experience a statistically significantly higher burden of dental caries — measured by the DMFT index and untreated caries — compared with adults without PD? __SNAPSHOT__ {"studyDesign":"Systematic review and meta-analysis of observational studies (all included studies were cross-sectional with control groups)","setting":"International; seven electronic databases and gray literature sources searched; institution types of included studies not reported","sampleSize":"n = 1,726 total (573 with PD; 1,153 controls) across 10 included studies","population":"Older adults with a confirmed diagnosis of Parkinson's disease compared with adults without PD; specific age ranges, disease severity, and medication details of included study populations not reported in the abstract","intervention":"Presence of Parkinson's disease (observational exposure)","comparator":"Adults without Parkinson's disease (controls)","primaryOutcome":"Dental caries experience assessed by: (1) the Decayed, Missing, and Filled Teeth (DMFT) index (k = 5 studies); and (2) untreated dental caries count (k = 4 studies); both reported as mean differences (MD) with 95% confidence intervals","followUp":"Not applicable (cross-sectional design across all included studies)","fundingSource":"Not reported"}
Key findings
Ten cross-sectional studies comprising 1,726 individuals (573 PD, 1,153 controls) were included. Meta-analysis of DMFT index (k = 5 studies) revealed no statistically significant difference between PD patients and controls (MD = −0.30; 95% CI: −5.18 to 4.57; p not reported). Meta-analysis of untreated dental caries (k = 4 studies) similarly showed no statistically significant difference (MD = 0.73; 95% CI: −1.66 to 3.12; p not reported). Both confidence intervals are wide and cross zero, indicating no detectable directional effect in either analysis. Heterogeneity statistics (I²) were not reported in the abstract. NNT and NNH are not calculable from these data. No adverse event data were reported, as this is an observational review. The overall strength of evidence was rated LOW by the GRADE framework, and the abstract characterizes the aggregate evidence as 'very-low-certainty.'
Practice implications
This meta-analysis did not detect a statistically significant difference in total caries burden (DMFT) or untreated caries between older adults with PD and matched controls. However, this null finding must be interpreted with considerable caution. All 10 included studies were cross-sectional, precluding any inference of causality or temporality. All studies exhibited a moderate risk of bias per the Newcastle-Ottawa Scale. The evidence base was rated LOW to very-low certainty by GRADE, meaning further research is very likely to change these estimates. The total PD sample (n = 573) is small relative to the complexity and heterogeneity of PD populations, and the wide confidence intervals for both meta-analytic outcomes indicate imprecision rather than a reliable null effect. Only the abstract was available for this summary, limiting full appraisal of heterogeneity statistics, sensitivity analyses, subgroup analyses by disease severity or medication class, and individual study characteristics. Prior narrative reviews and broader oral health systematic reviews have suggested worse overall oral health in PD patients — including higher rates of periodontal disease and plaque accumulation — and have noted that the relationship between untreated caries and PD is inconclusive across the literature, with some studies reporting higher rates and others finding similar or lower rates compared to controls. Patients with more advanced disease, greater motor impairment, polypharmacy (particularly anticholinergics causing xerostomia), or cognitive decline may represent higher-risk subgroups not adequately captured in aggregate analyses. This study does NOT establish that dental caries risk is equivalent in PD and non-PD populations; it establishes only that current pooled cross-sectional data are insufficient to confirm a statistically significant difference. Practice should not change based on this review alone; the clinical imperative for vigilant preventive dental care in PD patients remains. __LIMITATIONS__ All 10 included studies were cross-sectional, making causal inference impossible and precluding assessment of caries incidence over time.,All studies exhibited moderate risk of bias on the Newcastle-Ottawa Scale; no low-risk-of-bias studies were available.,Total PD sample size (n = 573) is small, and wide confidence intervals in both meta-analyses indicate substantial imprecision rather than a true null effect.,Evidence strength rated LOW to very-low by GRADE; results are highly susceptible to revision with future data.,Heterogeneity statistics (I²) not reported in abstract; extent of between-study variability is unknown.,DMFT is a composite index that cannot distinguish between decayed, missing, and filled components individually, limiting clinical specificity.,Confounders critical to caries risk in PD — including xerostomia from anticholinergics, diet, disease severity (H&Y stage), disease duration, cognitive status, and caregiver-assisted hygiene — are not reported as having been controlled.,Generalizability is limited: all included studies were cross-sectional, and the geographic, ethnic, and socioeconomic diversity of included samples is unknown from the abstract.,Funding source not reported, precluding assessment of potential sponsorship bias.,Only the abstract was available for full methodological appraisal. __BOTTOM_LINE_CATEGORY__ low_certainty __BOTTOM_LINE__ This systematic review and meta-analysis found no statistically significant difference in DMFT index (MD = −0.30; 95% CI: −5.18 to 4.57) or untreated caries (MD = 0.73; 95% CI: −1.66 to 3.12) between older adults with and without Parkinson's disease, but the evidence is rated low-to-very-low certainty, all studies were cross-sectional with moderate risk of bias, and confidence intervals are wide. This null result reflects current data insufficiency rather than established equivalence of caries risk. Neurologists and care teams should continue to advocate for routine preventive dental care in PD patients, particularly given known risk factors such as xerostomia from anticholinergic medications, motor impairment impairing oral hygiene, and polypharmacy.