Effect of radiation on the bone around healed, osseointegrated dental implants

ABSTRACT

This experimental study was designed to evaluate the bone reaction around endosteal implants after exposure to ionizing radiation, and to compare this reaction in two different types of implants; hydroxyapatite [HA] coated and titanium plasma sprayed implants. For each of twenty-four male white rabbits; the right femur was implanted with titanium plasma sprayed implant while the left side was implanted with HA-coated implant. After a period of 8 weeks during which the implant osseointegrated, the animals were divided randomly and equally [N=12] into 2 groups; control [C] and experimental [E]. In the later group, both femurs were exposed to cobalt 60 units; 200 rad per day, 5 days a week for 5 weeks. Standardized X Ray were taken for each implant, immediately postoperative as well as, 2nd, 4th, 8th and 20th week post-operative. Bone reaction was detected by measuring bone density around implants using gray scale analysis. Bone density in group C increased from 79 +/- 4.85 to 126.2 +/- 3.22 and from 77.8 +/- 3.16 to 135.6 +/- 4.24 for titanium plasma sprayed and HA- coated implants respectively, and in group E from 81.2 +/- 5.11 to 115.6 +/- 5.24 for titanium plasma sprayed implants and 78.4 +/- 3.64 to 124.9 +/- 4.93 for HA-coated implants. All differences were statistically significant [P<0.05] among each group, and statistically insignificant [P>0.29] between both groups. The results of this study suggested that, fractionated irradiation dose of 50 Gy might not induce an apparent deleterious effect on healed osseointegrated dental implants. Moreover, upon exposure to irradiation, HA-coated implants might provide a better bone reaction than titanium plasma sprayed implants