Development of Inflammatory Disease Model Protein, Genetic and Microbial Biomarkers

Gingivitis is a specific oral infectious disease that affects approximately 50% of the adult population on an average of 3 to 4 teeth. Although dental plaque is the primary etiology of most periodontal diseases, patients are not equally susceptible and do not respond similarly to professional care. Therefore, assessing the future risk of patients for developing gingivitis with possible subsequent progression to chronic periodontitis may help the clinician in elaborating a more accurate and suitable treatment plan for the patients and a better assessment of their prognoses. In fact, the prevention of plaque-induced gingivitis is still considered the first step in the maintenance of periodontal health.

Experimental gingivitis has been used widely to study the microbiology and the events that occur in the transition from a state of gingival health to inflammation. In a classical study by Löe and Theilade, periodontally healthy subjects were asked to cease all forms of oral hygiene for 3-4 weeks.

Studies of the levels of proinflammatory biomarkers have been of increased interest for the past decades. Since changes in the levels of these salivary biomarkers occur prior to clinical signs of gingivitis, their measurements may provide a more objective, earlier and accurate assessment of gingival inflammatory changes compared to the traditional bleeding and plaque indices.

Despite the clinical significance of gingivitis, little is know about the correlation between the levels of salivary biomarkers, the presence of periodontal pathogens and IL-1 polymorphism, and how this affect their susceptibility to gingivitis. If IL-1 polymorphism is indeed associated with increased levels of pro-inflammatory cytokines expression and the presence of specific periodontal pathogens, then screening for this polymorphism will be a valuable and necessary tool. As periodontal treatments, such as scaling and root planing, have been shown to be successful at decreasing the levels of IL-1 in the gingival crevicular fluid, a more aggressive treatment regimen may be warranted when the patient is genotype positive. If biomarkers in saliva and plaque biofilm can serve as accurate predictors of gingivitis, the ability for early detection of disease in patients is enhanced. Pro-inflammatory salivary biomarkers, specific pathogenic bacteria and genotype aid in establishing more accurate diagnostic and prognostic parameters of periodontal diseases, compared to current parameters (e.g. probing pocket depth, clinical attachment loss...) that reflect the history rather than the present and future status of disease. As a consequence, intervention can be initiated prior to irreversible tissue breakdown and oral health care costs may be reduced. Research efforts in the future should be directed toward the establishment of an affordable and practical chairside salivary test.

Inclusion criteria

• Caucasian subjects between 18-40 years of age (throughout the study)
• Dentition with a minimum of 20 permanent teeth
• Mean score of less than or equal to 1 for plaque index, gingival index and papillary bleeding
• Compliance with all requirements in the study and signing the informed consent

Exclusion criteria

• Current smokers, smokers who quit less than one year ago, or a pack-year history of more than or equal to 10 (pack-years will be calculated by multiplying the number of years smoked by the average number of cigarette-packs smoked per day)
• Antibiotic therapy within 3 months of baseline or the need for antibiotics for infective endocarditis prophylaxis or other conditions
• Chronic medications known to affect the periodontal status (calcium antagonists, anticonvulsives, immunosuppressives, anti-inflammatory medications…)
• Pregnancy or lactating mothers
• Combined score of greater than 1 for plaque index, gingival index, and papillary bleeding at the screening visit
• Current orthodontic or periodontal treatments
• History of alcoholism or drug abuse
• Untreated carious lesions or defective restorations which could exacerbate during a period of oral hygiene abstinence
• Diseases of the immune system or any medical condition that may influence the outcome (diabetes, neurologic or psychiatric disorders, systemic infections…)
• New oral contraceptives users within 3 months of baseline or those planning on starting oral contraceptives during the study
• Depo-Provera contraceptive injection users