This study was carried out to investigate pulpal changes occurring with the use of heavy forces, created by rapid palatal expansion appliances. Arcylic cap splint appliance is a type of rapid palatal expansion appliance which maintains the control of the vertical proportions, eliminates the influences of occlusion and provides maximum tooth support. Ten study and 10 control, a total of 20 teeth were examined histologically under light microscopy. Circulatory disturbances, disruption of the odontoblastic layer, signs of dentinal depositing and central fibrosis were observed as a result of the heavy forces acting on the anchor teeth. No contrariety was seen among buccal and lingual sights of the pulp in both of the study groups.

Keywords: Rapid Palatal Expansion, Pulp, Light microscopy