ABSTRACT
The mouth is the portal of entry of food this provides access to a wide array of microbes, the majority of which become part of the transient oral flora. Microbiological studies on samples taken from gingival pockets surrounds overdenture abutment teeth revealed different types of bacteria. The design of the overdenture prosthesis and supporting abutments affect the nature and quantity of bacterial found and that will be revealed in this study. This study was conducted to compare the microbiological changes occurring in gingival and periodontal tissue and gingival crevicular fluid as indicators of the condition of periodontium around abutments with different designs of abutment teeth of tooth supported mandibular overdenture. Subgingival bacteriological samples were taken from abutment's gingival crevice at the time of denture insertion and after three months to evaluate the effect of abutments design on the bacterial types as well as counts. The collected samples were cultured, identified and counted. A total of 20 male patients were divided into two equal groups according to abutment's length [Group I and II]. The patients' abutments were subdivided into two equal groups according to abutment's covering [A and B]. This study revealed an increase in anaerobic bacteria in both groups, with significant increase in Group I-A [patients rehabilitated with long abutments with copings] while all other groups have shown to significant difference before and after denture insertion. Insertion of overdenture accompanied with increase of anaerobic bacteria