Abstract
To the Editor:
The article by Radnai et al. (2009) concluded that periodontal treatment completed before the 35th week of pregnancy appeared to have a beneficial effect on birthweight and time of delivery (PTLBW). However, this study has three major shortcomings:
The authors have failed to control for confounding variables. Multiparity (Kramer, 1987; Vettore et al., 2008), one of the major risk factors for PTLBW, tended to be higher in the control group compared with the test group. Similarly, ‘Educational Level of Mothers’ and ‘Occupation of Fathers’ showed a borderline difference between groups. So, a multivariate analysis should have been performed to assess the association between periodontal disease and PTLBW. Another shortcoming is the inappropriateness of their criteria for classifying periodontal disease: at least at one site with ≥ 4 mm probing depth and bleeding on probing (BOP) at ≥ 50% of teeth. Probing depth is not sufficient to distinguish between periodontitis and gingivitis. In addition, pregnant women are more prone to have gingivitis and gingival enlargement, often associated with pseudopockets (≥ 4 mm). It has been demonstrated that the criterion used affects the relationship between periodontal status and PTLBW (Manau et al., 2008). The treatment group had a mean probing depth of 2.11 mm. Such a small initial mean probing depth is unlikely to alter levels of circulating cytokines significantly to affect PTLBW. Therefore, treatment would not reduce the risk of the mother having a preterm baby.