The effects of steel and titanium mandibular reconstruction plates on photon and electron beams

Abstract

The use of metal plates, designed to be screwed into the bone in reconstruction of composite mandibular defects is an accepted and widely used procedure in oral cancer therapy (Castillo et al, 1988; Sindet-Pedersen, 1988). Many of these patients must receive post-surgical radiotherapy in the course of their treatment because of possible residual microscopic disease. The effects of radiation on tissue-metal interfaces have been studied for photon (Dutreix & Bernard, 1966; Gibbs et al, 1976; Hudson et al, 1984) and electron beams (Weatherburn et al, 1975; Khan et al, 1976; Gagnon & Cundiff, 1980; Klevenhagen et al, 1982). They have been found to result in an enhancement of the dose to the tissue in the immediate vicinity of the interface on the side facing the beam. A search through the literature has revealed limited studies on the effects of radiation beams on metal mandibular implants of the oral cavity (Castillo et al, 1988; Scher et al, 1988). These investigations were confined to stainless steel and vitallium plates irradiated with 6 MV photons. In the last few years, titanium reconstruction plates have become available and are growing in popularity because of the increased strength relative to the thickness of the plate, greater tissue compatibility and easier adaptation to the bony fragments.

Reconstruction of large defects postmandibulectomy for oral cancer using plates and myocutaneous flaps: a long-term follow-up

“…On the other hand, ALLAL et al 1 , in an experimental study of dose variation in interface bone/titanium plates, concluded that failure of prosthetic osteointegration is unlikely to be explained by an overdose at the bone/titanium interface. DELACROIX et al 11 observed that with a steel prosthesis there was an increase of the dose (17.5 Gy) on the external side of the plate and a decrease (8 Gy) on the internal side when a mean dose of 50 Gy was applied. They concluded that by choosing titanium plates the dose of secondary radiation at the interface of the flap and plate might be reduced by more than 17%, making titanium a more suitable material for a prosthesis when radiation therapy is anticipated.…”

Effects of implantable biomaterials on radiation dosimetry

“…6 Other studies explain intuitive or anecdotal evidence of soft or hard tissue complications from radiation-dose enhancement proximal to metallic materials, such as gold dental crowns. 1,3,[7][8][9][10] Although the use of parallelopposed treatment fields minimizes these effects, the development of three-dimensional conformal techniques for treatment is reducing the prevalence of opposed fields, thus increasing the dose variances across interfaces between implants and normal tissue.…”

Spinal Implants and Radiation Therapy

“…Metallic implants attenuate the dose applied as a function of the difference between the atomic numbers of the tissues and implants [3][4][5][6][7][8] . The current approach to the treatment of a spinal metastasis is radiation therapy, either alone or in combination with surgery.…”

“…Fig. Since the interface effect depends on the density (atomic number) of the tissue or implant and the atomic number of the plastic chest tube is smaller than that of the polymethylmethacrylate, we did not expect the chest tube to increase the backscattering capacity of the cement bars [3][4][5][6][7][8] . Fig.…”