The aim of this study was to evaluate longitudinally the bone-healing process by measuring volumetric changes of the extraction sockets in head and neck cancer patients undergoing radiotherapy after tooth extraction. A total group of 15 patients (nine males, six females) undergoing tooth extraction at the Department of Periodontology (University Hospital KULeuven) were enrolled after giving informed consent. In seven patients, teeth presenting a risk for complications and eventual radionecrosis were extracted prior to the radiotherapeutical procedure. Monitoring of bone healing was performed by evaluating the volumetric changes of the alveoli by cone beam CT scanning (CBCT) at extraction and after 3 and 6 months. In parallel, a similar longitudinal evaluation of extraction sites was done in a control group of eight patients. Within this pilot-study, a total of 15 healing extraction sockets were evaluated and followed up. There was a significant difference in volumetric fill up of extraction sockets in test group vs. control group at three (37.1 +/- 7.9%) vs. (54.6 +/- 4.0%) and 6 months (47.2 +/- 8.8%) vs. (70.0 +/- 7.3%), respectively. The present pilot study demonstrated the clinical usefulness of CBCT for evaluation of extraction socket healing. The study objectively demonstrates the delayed bone healing after tooth extraction in irradiated head and neck cancer patients. Considering the limitations of this pilot study, a potential effect of radiotherapy on further jaw bone healing after pre-therapeutic tooth extractions should be further explored.