The influence of bacteria and irritation in the initiation of periodontal disease in germfree and conventional rats

Abstract

Within the conditions of the experimental design, this study has provided laboratory evidence that microorganisms were necessary for the occurrence of inflammatory periodontal disease. Furthermore, this investigation has shown that the presence of both local irritation and microorganisms was necessary to produce periodontal inflammation. However, neither factor alone was capable of producing the inflammation. The results of this study have shown that a type of dental calculus may be formed in the absence of microorganisms. However, the same results have demonstrated that the presence of microorganisms greatly facilitates the formation of calculus. The presence of polymorphonuclear leukocytes in the gingival crevices and tissues could not be explained on the basis of bacteria and/or irritation. It was postulated that these cells are a normal component of the gingival tissues of these animals and that their presence does not constitute a pathologic process. The findings of the present study were considered with those of other studies. From this comparison it was suggested that differences in animal species and strains should be considered when evaluations and extrapolations of experimental results are made.

Ligature‐associated bacterial profiles are linked to type 2 diabetes mellitus in a rat model and influenced by antibody treatment against TNF‐α or RAGE

“…Thus, subgingival placement of the ligature increases biofilm formation, and a direct comparison between ligature‐induced PD in rats and naturally occurring PD in humans is not possible (Graves et al, 2008). It is, however, interesting that while trauma from the ligature obviously play a role in periodontal disease progression in the PD rat model, a study in germfree rats showed that no bone loss occurred in the absence of biofilm accumulation (Rovin, Costich, & Gordon, 1966). Thus, progressive bone loss in the ligature‐induced PD model in rats seems to be dependent on bacterial accumulation and subsequent colonization, which suggests that the model is suitable for studies on subgingival bacterial profiles in PD.…”

Experimental Bacterial Endocarditis After Dental Extractions in Rats with Periodontitis

“…The animals were then maintained on a powdered, high-sucrose diet (Keyes' diet 2000; Teklad, Madison, Wis) ad libitum for 14 weeks. Such a regimen is sufficient to initiate periodontal lesions in the rat [23][24][25]. Group 3 comprised animals fed a normal diet in the animal facility for 14 weeks.…”

“…Periodontal disease in rats is an infectious process [23,29]. Under natural conditions, however, the rat is very resistant to periodontal diseases.…”

Experimental Gingivitis in the Albino Hamster

“…A review of the literature reveals that periodontal inflammation does not occur in the absence of microorganisms. For example, in an investigation of periodontal disease in rats, Rovin, Costich, and Gordon (1966) observed that, in germfree rats, local irritation in the form of silk ligatures placed at the cervical margins of the first molars was not sufficient to cause periodontal inflammation. Inflammation occurred only in the presence of .…”