Mean annual attachment, bone level, and tooth loss: A systematic review

Background: Rate of progression of periodontitis has been used to inform the design of classifications of periodontal diseases. However, the evidence underpinning this topic is unclear and no systematic review has yet been conducted.

Objectives: The focused question for this systematic review was: in adults, what is the progression of periodontitis in terms of clinical attachment loss, radiographic bone loss, and tooth loss?

Data sources: Highly sensitive electronic search was conducted for published data in MEDLINE, EMBASE, LILACS, and unpublished grey literature in OpenGrey up to February 2016. Reference lists of retrieved studies for full-text screening and reviews were hand-searched for potentially eligible studies.

Study eligibility criteria and participants: Prospective, longitudinal observational studies with follow-up of at least 12 months and presenting data on the primary outcome, change in clinical attachment level, in adults (age ≥18 years). Secondary outcomes, tooth loss and bone level change, were only assessed in studies reporting the primary outcome. Studies investigating specific disease populations or only on treated periodontitis patients were excluded.

Study appraisal and synthesis methods: Risk of bias and methodology were assessed using the Newcastle-Ottawa Scale with two additional questions on security of outcome assessment. Studies were pooled by abstracting or estimating mean annual attachment or bone level change and annual tooth loss. Random effects meta-analysis was conducted with investigation of effect of potential modifiers where possible.

Results: A total 11,482 records were screened for eligibility; 33 publications of 16 original studies reporting on more than 8,600 participants were finally included as eligible for the review. The studies represented populations from both developing and developed economies. Mean annual attachment loss was 0.1 mm per year (95% CI 0.068, 0.132; I² = 99%) and mean annual tooth loss was 0.2 teeth per year (95% CI 0.10, 0.33; I² = 94%). Observational analysis of highest and lowest mean attachment change quintiles suggested substantial differences between groups with minimal annual change in the lowest quintile and an average deterioration of 0.45 mm mean attachment loss per year in the highest group. This value increased to 0.6 mm per year with periodontitis alone. There was surprisingly little effect of age or gender on attachment level change. Geographic location, however, was associated with more than three times higher mean annual attachment loss in Sri Lanka and China (0.20 mm, 95% CI 0.15, 0.27; I² = 83%) vs North America and Europe (0.056 mm, 95% CI 0.025, 0.087; I² = 99%) P < 0.001.

Limitations: There were a limited number of studies (N = 16), high variability of design in key study components (sampling frames, included ages, data analyses), and high statistical heterogeneity that could not be explained.

Conclusions: Within the limitations of the research, the data show that mean annual attachment level change varies considerably both within and between populations. Overall, the evidence does not support or refute the differentiation between forms of periodontal diseases based upon progression of attachment level change.