Comparison of Different Periodontal Surgeries: A Longitudinal Meta-Analysis

Objectives: Guided tissue regeneration (GTR) and enamel matrix derivatives (EMD) are the two most commonly used surgical techniques for periodontal regeneration. Several meta-analyses showed that GTR and EMD achieved better treatment outcomes such as pocket depth reduction and clinical attachment level gain in one year compared to periodontal flap operation. However, their long-term benefits remain unclear. The aim of this study is therefore to conduct a longitudinal meta-analysis of for the long-term differences in treatment outcomes between periodontal regeneration and flap operation.
Methods: A systematic literature search was conducted using the Medline, EMBASE, Pubmed and CENTRAL databases up to Dec 2014. Treatment outcomes were changes in probing pocket depth (PPD) and clinical attachment level (CAL). We extracted data reported at different time points after periodontal surgery and incorporated all data into the same model to estimate the trend in the treatment outcomes. The restricted cubic spline model was used to evaluate the nonlinear trend, and as some studies reported outcomes at multiple time points. Various correlation structures for data reported by the same study were considered.
Results: A total of 40 randomized Controlled Trials were included. There are 10 time points for PPD and CAL, and the follow-up length ranged from 0.5 year to 8 years. The results are similar under the different correlation structures. GTR and EMD achieve greater PPD reduction and CAL gain than FO in both short-term and long-term follow-up, but the uncertainty in their long-term benefits was large due to few studies reporting results after one year.
Conclusions: Compared with traditional flap operation, periodontal regeneration surgeries achieved greater PPD reduction and gain in CAL after one year, and its effects may last for 5 to 8 years.