In search of appropriate measures of periodontal status: The Periodontal Profile Phenotype (P3 ) system

Abstract

Background: This paper focuses on Periodontal Profile Class (PPC), a component of the Periodontal Profile Phenotype (P³ ) System that may be more representative of the periodontitis phenotype than current case definitions of periodontitis. Data illustrate the unique aspects of the PPC compared with other commonly used periodontal classification indices.

Methods: Latent Class Analysis (LCA) identified discrete classes of individuals grouped by tooth-level clinical parameters. The analysis defined seven distinct periodontal profile classes (PPC A through G) and seven distinct tooth profile classes (TPC A through G). This LCA classification was an entirely data-derived agnostic process without any preconceived presumptions of what constituted disease.

Results: Comparing the PPC with the Centers for Disease Control/American Academy of Periodontology (CDC/AAP) and European indices, the PPC is unique in that it contains four disease classes not traditionally used. Less than half of individuals classified as Healthy by both the CDC/AAP and European indices were Healthy using the PPC. About 25% of those classified as Severe by CDC/AAP and European indices were PPC-Severe. The remainder spread out over the High Gingival Index, Posterior Disease, Tooth Loss, and Severe Tooth Loss phenotypes.

Conclusions: The PPC classification provides a significant departure from the traditional clinical case status indices that have been used, but has resulted in clinical phenotypes that are quite familiar to most clinicians who take notice of the distribution of missing teeth, areas of recession, diminished periodontal support, and other aspects of the dentition while conducting a periodontal examination. The mutually exclusive categories provided by the PPC system provide periodontal clinical summaries that can be an important component of precision dentistry.

Keywords: Diagnosis; epidemiology; gingivitis; periodontitis.

FIGURE 1

Potential clinical utility of the University of North Carolina periodontal profile phenotype (P³) system. This figure provides a conceptual framework for the development and clinical utility of the P³ system containing the three major domains of Diagnosis, Risk. and Outcome. This is a work in progress, and the colors indicate areas supported by a publication. The dark blue color indicates the components of the P³ system that are under development.

FIGURE 2

Clinical measures for each tooth profile class. TPC, Tooth Profile Class; GI = Gingival Inflammation; Interprox, Interproximal Disease; DimPerio, Diminished Periodontium; iCAL, mean interproximal (i.e., adjoining tooth surfaces, four sites) attachment loss in mm; dAL = mean direct attachment loss in mm (buccal and lingual surfaces, two sites); iPD, mean interproximal probing depth (PD) in mm; dPD, mean direct PD in mm (buccal and lingual surfaces); iCEJ, mean distance from free gingival margin to cementoenamel junction (CEJ) in mm measured interproximally, negative indicates recession, i.e., CEJ exposed and above the free gingival margin; dCEJ, mean distance from free gingival margin to CEJ in mm measured directly at buccal and lingual surfaces (two sites), negative indicates recession, i.e., CEJ exposed and above the free gingival margin; BOP, mean bleeding on probing as percent of sites (six sites per tooth); GI, mean Gingival Index score as measured across buccal sites. GI is scored 0 to 3; PQ, mean Plaque index score measured across buccal sites. PQ is scored 0 to 3; Crown, proportion of teeth with crowns

FIGURE 3

Distribution of tooth profile classes (TPC) by person profile class (PPC) in the Dental ARIC study. Sev, severe disease; iDis, interproximal disease; DimPer, diminished periodontium; GI, gingival inflammation; Crn, crown on tooth; Rec, recession; T, tooth; T L, tooth loss

FIGURE 4

Intraoral distribution of tooth profile class (TPC) by periodontal profile class (PPC) by tooth type. GI, gingival index; Dis, disease; Dim, diminished

FIGURE 5

Mean interproximal attachment level, mean probing depth, extent bleeding on probing, and mean gingival index by periodontal profile class (PPC) and tooth type