Densitometric Evaluation of Calcium Sulfate Hemihydrate as a Bone Graft Substitute around CAD/CAM Machined Zirconium Dioxide Implants

This experimental study was conducted to evaluate the effect of β–calcium sulfate hemihydrate (CSH) as a bone graft substitute on the bone response around CAD/CAM machined zirconium dioxide (ZrO2) implants. Materials and methods: Forty ZrO2 implants were digitally designed and manufactured using computer–aided design/ computer aided–manufacturing CAD/CAM machine. Twenty New–Zealand rabbits were included in the experiment and a bed was made for implantation in each head of the left femur. Each animal received a ZrO2 implant in the mesial femoral head and this group of implants was considered as a control group. Then the calcium sulfate hemihydrate was placed in the implant bed at the distal femoral head followed by fixation of an implant, and this group was considered as an experimental group. The twenty rabbits were randomly allocated into four groups, to represent the study periods i.e. 3 days, 7days, 14 days, and 21 days. Bone response was assessed around each of the forty implants by measuring the bone mineral density using densitometric analysis of the digital periapical radiological image which was taken after the euthanization of the animals according to study intervals. Results: The results showed a statistically significant difference between the control group (ZrO2 implants) and the experimental group (ZrO2 implants with CSH) in bone mineral density. Conclusions: the use of CSH as an artificial bone graft around ZrO2 implant is beneficial for increasing bone formation around the implant as it increases bone density.