Gingival Inflammation and Microbial Load in Iraqi Patients Fitted with Fixed Orthodontic Appliances: A Longitudinal Study

Background: Fixed orthodontic appliances are widely used to correct malocclusions and improve dental aesthetics and function. However, their placement can significantly alter the oral microenvironment, promoting plaque accumulation and microbial colonization, which may lead to gingival inflammation and periodontal complications. In particular, opportunistic pathogens such as Staphylococcus aureus and Candida albicans have been reported to proliferate in orthodontic patients. Methods: A total of 40 (20 males, 20 females) patients undergoing fixed orthodontic treatment were enrolled in this longitudinal study. Unstimulated saliva samples were collected by passive drooling method (Navazesh, 1993) at three intervals: baseline (T0), two weeks (T1), and four weeks (T2) after appliance placement. Gingival Index (GI) was recorded at each interval. Saliva samples were cultured for microbial identification, and quantitative real-time PCR was performed to detect S. aureus and C. albicans using species-specific primers. Data were statistically analyzed using one-way ANOVA and Duncan's multiple range test at a significance level of p ≤ 0.05. Results: The study revealed a statistically significant increase in GI scores from baseline to four weeks. Similarly, the microbial load of S. aureus and C. albicans increased progressively across the study period, showing statistically significant differences between baseline and four weeks (p ≤ 0.05). Conclusions: Fixed orthodontic appliances may influence the salivary microbial flora and gingival health. The findings emphasize the importance of maintaining optimal oral hygiene and regular professional care during orthodontic treatment to minimize microbial accumulation and gingival inflammation.