Maxillary transverse deficiency is a common skeletal problem. When the patient is younger, it is treated by rapid palatal expansion by using orthodontic appliances. If this fails or the patient is older, which means skeletal growth is completed, surgically aided rapid palatal expansion (SARPE) becomes necessary. In this technique, after the osteotomies have been made, the two maxillary bones are distracted by tooth-borne device. Since a tooth-borne device will apply the distraction forces on the teeth, the pulp volumes may change. Our aim was to investigate the volume changes of the tooth pulps after SARPE in which a tooth-borne device was used. We scanned our database and included 20 patients (7 males and 13 females) aging between 16 and 30 (mean 19.5±3.97) to this retrospective study. All the patients had undergone SARPE surgeries and they had pre-surgery and postconsolidation cone beam computerized tomography (CBCT) images. All the surgeries had been done in similar ways; all the patients had used similar tooth-borne modified acrylic bonded expansion device. We divided the maxillary teeth into three groups: the incisors, the premolars and the molars. We imported the CBCT images of each patient into 3D Slicer software. We calculated volumes of pulps for all maxillary teeth. We compared volumes with paired t test. Statistical significance level was accepted as P< .05. The devices had been left in place between 83 and 179 days including distraction and consolidation periods (mean 121.35±27.83 days). Amount of the expansions varied between 6.03mm and 11.16mm (mean 7.19±1.18mm). We found a statistically significant decrease of the pulp volumes in incisor, premolar and molar teeth (P<.001) between pre-surgery and postconsolidation periods. When using tooth-borne devices in SARPE, their impacts on teeth pulps should also be considered.