From September 2015 to September 2018, we collected cases that were admitted to our institution for IA detection via digital subtraction angiography or computer tomography angiography examination. During the same period, we also recruited cases that were diagnosed without IAs or several volunteers. A total of 281 cases provided written informed consent and were divided into two groups (166 cases in the IA group and 115 cases in the non-IA group). The privacy of the patients was strictly protected, and the protocol of this study was approved by our ethics committee. We subjected all recruited cases to periodontal health examination through a standardized approach in a dental unit by using a standard dental light, compressed air, a mouth mirror, and digital panoramic radiography free of charge. Periodontal disease was diagnosed on the basis of the clinical and radiographic criteria described by the 1999 Consensus Classification of Periodontal Diseases.
Inclusion criteria were as follows: (1) individuals who were 18–80 years of age, (2) individuals with IAs and hospitalized volunteers (non-IA) who wanted to participate in this study, and (3) individuals who underwent the examination of periodontal health condition. Exclusion criteria included (1) individuals with acute ruptured aneurysms; (2) individuals receiving antihypertensive therapy with calcium channel blockers, such as Nifedipin; (3) individuals with severe cardiovascular diseases or cerebral ischemic stroke; (4) individuals with malignant diseases, chronic inflammatory diseases, or antibiotic use within 2 weeks; and (5) individuals missing clinical follow-up. Baseline demographic information (including age, sex, clinical presentation, smoking and drinking history, diabetes, hypertension, and hypercholesterolemia) and IA characteristics (location, size, shape, and quantity) were recorded.
Assessment of periodontal diseases
Periodontal diseases mainly include periodontitis and gingivitis. Gingivitis severity was assessed by using the gingival index (GI) system, which is based on the various tendencies of gingival bleeding after gingival irritation. A high index number (> 1.1) was defined as severe gingivitis. Periodontitis was evaluated by using the plaque index (PI), clinical attachment loss (CAL), and alveolar bone loss (ABL). Plaque and gingivitis were scored at four sites per tooth (buccal, mesiolingual, lingual, and distolingual) and averaged for each subject. We presented these parameters in accordance with the following definitions: First, the CAL was examined by inserting the tip of a CPI probe to measure the distance between the pocket and cementoenamel junction. Attachment levels were analyzed as continuous variables, and mean CAL > 4 mm was considered as severe periodontitis. Second, dental plaque was scored in accordance with the PI system, which is based on the same principle as the GI system. We divided PI into 4 sites (≤ 0.5, 0.51–1.0, 1.01–1.5, and > 1.5). A high score represented severe periodontitis. Third, ABL levels were measured as the distance from the cementoenamel junction to the most apical extension of the bony defect. We stratified the ABL into < 3, 3.00–4.00, 4.00–5.00, and > 5.00 mm. Among these periodontal parameters, the CAL was defined as the primary criterion of periodontitis.
Data were presented as mean ± standard deviation or expressed in terms of frequencies and percentages. Independent sample t-tests and chi-square tests were performed to test for differences in continuous or categorical variables between the IA group and the non-IA group, respectively. Subgroup univariate and multivariate logistic regression analyses were performed to identify the independent contribution of gingivitis and periodontitis parameters (including GI, CAL, PI, and ABL) to the incidence of IAs. Odds ratios (ORs) and 95% confidence intervals (CIs) were given for all periodontal parameters. A two-sided p value of < 0.05 was considered to be significant. Statistical analysis was performed by using SPSS 22.0 software (SPSS Inc., Chicago, IL, USA).