Prostaglandin E2 levels in gingival crevicular fluid during tooth- and bone-borne expansion

The purpose of this study was to compare Prostaglandin E(2) (PGE(2)) levels in gingival crevicular fluid (GCF) of young adults with maxillary constriction during tooth- and bone-borne expansion. Thirty patients, 15 females and 15 males, with a mean age of 17.3 +/- 2.8 years were divided into three groups. Group I consisted of 10 patients, five females and five males, treated by transpalatal distraction (TPD) as a bone-borne device, group II 10 patients, five females and five males, with a Hyrax appliance as a tooth-borne device, and a control group of 10 patients, five females and five males, without any expansion appliances. GCF samples were collected with filter paper strips at six observation periods in order to evaluate the effect of heavy orthopaedic forces in both groups. In group II, the samples were additionally collected at two pre-treatment time points in order to evaluate the effect of the forces generated by the separators. An automated enzyme immunoassay was used to measure PGE(2) in the GCF. The differences within the groups were evaluated with a pairwise t-test and the differences between the groups were determined by the Mann-Whitney U-test. The mean PGE(2) level was significantly elevated on day 4 after placement of the separators in group II (P < 0.05). The PGE(2) values in group II were significantly different to those in group I and the controls at all observation periods. Lower PGE(2) levels were observed in group I compared with group II and the controls. Expansion using the TPD method could potentially enhance the prognosis of the teeth by inducing more skeletal dental changes when compared with the Hyrax appliance.