Temporal Alterations in Salivary Microflora Following Complete Removable Denture Insertion: A Longitudinal In Vivo Study

Abstract

Placement of complete removable dentures (CRDs) in edentulous subjects causes a radical alteration of the oral environment, modifying salivary composition and increasing microbial colonization. The denture base, composed primarily of Polymethyl Methacrylate (PMMA), is an unshedding surface, facilitates biofilm formation. In the long term, this may cause change in oral microbial flora, predisposing the subject to infection such as denture stomatitis and mucosal infections. While widespread use of complete removable dentures (CRDs) has occurred, limited longitudinal data exist regarding the change in microbial dynamics over time and their association with clinical variables.

The present longitudinal in vivo study was conducted to assess modification of microbial salivary flora in 35 edentulous subjects at three successive intervals: prior to denture placement (T0), one month after placement (T1), and three months after placement (T2). Unstimulated saliva was collected and plated on selective media to provide colony-forming units (CFUs) of Streptococcus pyogenes, Streptococcus mutans, Candida albicans, Escherichia coli, and Bacteroides fragilis. Concurrent clinical assessment of oral hygiene, mucosal status, and denture fit were taken. Statistical comparison revealed Candida spp. exhibited linear increase with maximal counts at T2, which correlated significantly with mucosal lesions (r = 0.90, p < 0.001). Streptococcus pyogenes and S. mutans were highest at T1 and reduced at T2, while E. coli and B. fragilis increased steadily.

The results indicate that time-dependent microbiological changes following complete removable denture placement are best related to prosthetic hygiene status and fit. An active approach through patient education, microbial screening on a routine basis, and early clinical intervention can minimize the risk of infection with the prosthesis and ensure improved patient outcomes and success of the denture in the long term.