Comparison between rapid and slow palatal expansion: evaluation of selected periodontal indices

The aim of this pilot study was to evaluate the periodontal effects during rapid palatal expansion (RPE) or slow palatal expansion (SPE) and to compare them by means of some clinical indices, in order to establish the possible differences and advantages of one of these treatments in periodontal terms.

10 patients (aged 6 to 7 years; average age 6.3 years) were submitted to RPE treatment and other 10 patients (aged 6 to 8 years, average age 6.3 years) to SPE treatment. They were treated with the Haas expander. The selected clinical indices (plaque index, PI; papillary bleeding index, PBI; probing pocket depth, PPD) were collected three times during the treatment (t0, detected 7 days after the periodontal prophylaxis, at the beginning of the active orthodontic therapy; t1, detected during the active therapy; t2, detected after retention). All measurements were performed by the same examiner. The protocol was approved by the ethics committee.

The effects of the prophylaxis were excellent to control inflammation and dental plaque before the beginning of the orthodontic-orthopaedic treatment, as in both the two groups, the PI and the PBI values were equal to 0.In the group receiving slow expansion, the PPD remained unchanged from t0 to t1, while it significantly increased from t0 to t1 in the group of rapid expansion. At t2 the values of the two groups returned to be overlapping.

Both rapid and slow expansion treatments present potential irritation effect (increase of PI index and PBI index) on the periodontium, suggested by the significant increase of PI and PBI from t0 to t1 in both the two groups; therefore prophylaxis and periodic controls are very important. There are no long-term benefits that might be referred unequivocally to one of the two treatments in terms of periodontal consequences, as demonstrated by the lack of significant differences between the two groups at t2.