Clinical utility of a genetic susceptibility test for severe chronic periodontitis: a critical evaluation.

BACKGROUND

A genetic susceptibility test for severe chronic periodontitis is now commercially available. It detects the simultaneous presence of a specific form of two interleukin genes--allele 2 at the IL1A+4845 and IL1B+3954 loci. Patients are referred to as being "genotype-positive" if both of these alleles are present. A fundamental premise of the test is that a combination of these alleles is responsible for increased secretion of IL-beta, which results in a hyperinflammatory response to a bacterial challenge, thereby predisposing a person to develop severe chronic periodontitis.

TYPES OF STUDIES REVIEWED: The authors reviewed controlled clinical trials that assessed the association between specific genotypes and the patient's susceptibility to increased bleeding on probing, periodontitis and loss of teeth or dental implants.

RESULTS

The relationship between specific IL-1 genotypes and the level of IL-1beta in the gingival crevicular fluid is unclear. Similarly, the ability of the genetic susceptibility test to forecast which patients will develop increased bleeding on probing, periodontitis, or loss of teeth or dental implants is ambiguous.

CLINICAL IMPLICATIONS: Additional prospective clinical trials are needed to determine the risk of developing periodontitis or peri-implantitis when allele 2 at the IL1A+4845 and IL1B+3954 loci is present. Therefore, it is unclear how results of the genetic susceptibility test can be used to alter patients' periodontal maintenance schedules or to change treatment regimens in periodontally symptomatic or asymptomatic patients.