The Effects of Palatal Expansion Therapy on the Periodontal Supporting Tissues

Four periodontal parameters were examined to determine the effect of rapid and slow palatal expansion techniques on the supporting structures at the buccal aspect of the maxillary first permanent molars. The parameters examined included the levels of crestal alveolar bone and soft tissue attachment (relative to the cemento-enamel junction), the depth of the gingival sulcus, and the height of the attached gingiva. The area between the buccal roots was inspected for possible furcation involvement. Twenty-eight patients had experienced a rapid technique utilizing a tissue-born, fixed, split-acrylic appliance, while thirty-three patients had been treated with the quad-helix appliance associated with slow expansion therapy. At the time of measurement, the rapid and slow groups demonstrated a mean increase in maxillary first molar width of 4.6mm. and 4.3mm. respectively. A group of twenty-eight post-orthodontic patients who had not undergone palatal expansion therapy was utilized as a control. The results indicate a trend toward a somewhat greater tissue response to the rapid expansion palatal expansion technique. This included lower crestal bone and attachment levels, as well as a larger amount of attached gingiva. Sulcus depth measurement varied between the three groups involved. Comparisons between the rapid and slow expansion groups demonstrated statistically significant differences in bone and attachment levels at the left molar (P 0.01) and bone levels only on the right side (P 0.05). Although the mean differences were clinically small, (less than 0.5mm.), and no areas of furcation involvement were discovered, the largest percentage of those patients exhibiting the lowest bone and attachment levels were found in the rapid expansion group. Many variables were examined; however, it would be difficult to predict individual susceptibility to tissue loss from the present study