Diagnostic Performance of Cone-beam Computed Tomography Low Dose Protocol on the Assessment of Bone Graft Loss Around Dental Implants – An Ex Vivo Study

Purpose: To investigate the influence of low dose protocols through tube current reduction on two cone-beam computed tomography (CBCT) devices on the evaluation of bone graft loss adjacent to titanium and zirconium implants. Materials and Methods: Twelve titanium and twelve zirconium implants were placed in dry mandibles. Gaps of at least 2 mm were created around the implants and filled with bone graft. In half of the samples the graft was removed up to the third implant thread. Images were acquired in Eagle 3D and OP300 CBCT devices with different dose protocols (tube current from 4 to 12.5mA) and were evaluated by 7 observers. Diagnostic values were calculated and compared between implant material and dose protocols by two-way ANOVA (significance level 5%). Results: For Eagle 3D, zirconium implants displayed lower diagnostic values than titanium, regardless of the protocol used (p<0.05), while protocols did not affect the diagnostic values (p≥0.05). For OP300, zirconium implants presented lower values (p<0.05) compared to titanium implants. Also, there is higher sensitivity for high dose protocol compared to the low dose protocol (p<0.05). Conclusions: Implant material influences bone graft loss detection, with lower diagnostic values for zirconium implants. Low dose protocols can be effectively used for titanium implant assessment; however, high dose protocols may be required for bone graft loss around zirconium implants.