Background: The aim of this study is to perform an updated systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating the efficacy of scaling and root planing (SRP) in reducing the preterm-birth and low-birth-weight risks to analyze important subgroups and to further explore heterogeneity and bias risks in the pooled studies.
Methods: The entire Cochrane Library was searched (from 1990 to September 2011), MEDLINE (from 1950 to September 2011), CINAHL (from 1980 to September 2011), University of Michigan School of Dentistry "Dentistry and Oral Sciences" database (from 1990 to September 2011), conference proceedings, and the ClinicalTrials.gov database. Authors were contacted when clarification was needed. Selection criteria included the following: 1) RCTs that reported preterm-birth risk (<37 weeks) outcomes, 2) compared SRP treatment to either placebo or no treatment in pregnant patients with periodontitis, and 3) had a probing depth >4 mm or clinical attachment loss >2 mm for ≥ 1 site. Reviewers independently extracted data from each included study using a standardized, piloted form and assessed quality using a risk-of-bias tool modeled after Cochrane, and discrepancies were resolved. A random-effects model was used to calculate relative risks and 95% confidence intervals (CIs) for pooled data. For subgroup analysis with heterogeneity <50%, a fixed-effects model was used.
Results: After abstract review, 12 studies were identified by the search, and 11 were included in the main meta-analysis (preterm birth <37 weeks). Overall quality and design of included studies was fair or good. For the main meta-analysis, results ranged from risk ratio with periodontal treatment 0.14 (95% CI = 0.01, 2.55) to 1.24 (95% CI = 0.93, 1.67) for an overall risk ratio of 0.81 (95% CI = 0.64, 1.02). When analyzed separately by subgroup for excess prematurity risk, the high-risk group (overall prematurity of 22.2% to 62.8%) showed combined risk ratios of 0.66 (95% CI = 0.54, 0.80). Remaining studies (overall prematurity of 4.0% to 10.4%) showed combined risk ratio of 0.97 (95% CI = 0.75, 1.24).
Conclusions: This systematic review and meta-analysis indicates statistically significant effect in reducing risk of preterm birth for SRP in pregnant women with periodontitis for groups with high risks of preterm birth only. Future research should attempt to confirm these findings and further define groups in which risk reduction may be effective.