Effect of direct relining on stresses at the denture base and the metal frame of removable partial dentures

The Kennedy Class I removable partial denture (RPD) can cause stress to supporting hard and soft tissues and may lead to harmful effects. The purpose of this study is to investigate the pattern of these stresses in three different positions before and following a relining procedure. Ten patients, five males and five females, with a lower distal extension RPD and an opposing upper class III type RPD were selected for this study. Strain gauges together with a strain gauge indicator were used to study the pattern of stresses in three selected positions. Some changes were significantly different at the site of the denture base and at the metal frame near the direct retainer. After relining, the stresses were shared partially by the abutments and partially by the tissues. Maximum stresses were reported during swallowing. No significant difference was noticed between males and females.