Postoperative irradiation after implant placement: A pilot study for prosthetic reconstruction.
OBJECTIVE
On maxillofacial tumor patients, oral implant placement prior to postoperative radiotherapy can shorten the period of prosthetic reconstruction. There is still lack of research on effects of post-implant radiotherapy such as healing process or loading time, which is important for prosthodontic treatment planning. Therefore, this study evaluated the effects of post-implant local irradiation on the osseointegration of implants during different healing stages.


METHODS
Custom-made implants were placed bilaterally on maxillary posterior edentulous area 4 weeks after extraction of the maxillary first molars in Forty-eight Sprague-Dawley rats. Experimental group (exp.) received radiation after implant surgery and the other group (control) didn't. Each group was divided into three sub-groups according to the healing time (2, 4, and 8 week) from implant placement. The exp. group 1, 2 received 15-Gy radiation 1 day after implant placement (immediate irradiation). The exp. group 3 received 15-Gy radiation 4 weeks after implant placement (delayed irradiation).


RESULTS
The bone mineral density (BMD) was significantly lower in the immediate irradiation groups. BMD was similar in the delayed irradiation group and the control group. The irradiated groups exhibited a lower bone-to-implant contact ratio, although the difference was not statistically significant. The irradiated groups also exhibited a significantly lower bone volume and higher empty lacuna count than the control groups. No implant failure due to local irradiation was found in this study.


CONCLUSIONS
Within the limits of this study, the timing of local irradiation critically influences the bone healing mechanism, which is related to loading time of prostheses.
Department of Advanced General Dentistry, Dankook University College of Dentistry, Cheonan, Republic of Korea.
Re-Mee
0000-0001-8512-9134
RM
Doh
Department of Periodontology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Republic of Korea.
Sungtae
S
Kim
Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Republic of Korea.
Ki Chang
KC
Keum
Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Republic of Korea.
Jun Won
JW
Kim
Department of Prosthodontics, Yonsei University College of Dentistry, Seoul, Republic of Korea.
June-Sung
JS
Shim
Division in Anatomy and Development Biology, Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Republic of Korea.
Han-Sung
HS
Jung
Department of Advanced General Dentistry, Yonsei University College of Dentistry, Seoul, Republic of Korea.
Kyeong-Mee
KM
Park
Division in Anatomy and Development Biology, Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Republic of Korea.
Moon-Kyu
MK
Chung
Empty lacuna; Head and neck cancer; Implant; Local irradiation; Postoperative radiotherapy