The dose-dependent impact of γ-radiation reinforced with backscatter from titanium on primary human osteoblasts

Lisa Printzell; Janne Elin Reseland; Nina Frederike Jeppesen Edin; Hanna Tiainen; Jan Eirik Ellingsen

doi:10.1080/26415275.2023.2209116

The dose-dependent impact of γ-radiation reinforced with backscatter from titanium on primary human osteoblasts

Biomater Investig Dent. 2023 May 16;10(1):2209116. doi: 10.1080/26415275.2023.2209116. eCollection 2023.

Authors

Lisa Printzell¹, Janne Elin Reseland², Nina Frederike Jeppesen Edin³, Hanna Tiainen², Jan Eirik Ellingsen¹

Affiliations

¹ Department of Prosthodontics, Faculty for Dentistry, Institute of Clinical Dentistry, University of Oslo, Oslo, Norway.
² Department of Biomaterials, Faculty for Dentistry, Institute of Clinical Dentistry, University of Oslo, Oslo, Norway.
³ Department of Physics, Faculty of Mathematics and Natural Science, University of Oslo, Oslo, Norway.

Abstract

In head and neck cancer patients receiving dental implants prior to radiotherapy, backscatter from titanium increases the radiation dose close to the surface, and may affect the osseointegration. The dose-dependent effects of ionizing radiation on human osteoblasts (hOBs) were investigated. The hOBs were seeded on machined titanium, moderately rough fluoride-modified titanium, and tissue culture polystyrene, and cultured in growth- or osteoblastic differentiation medium (DM). The hOBs were exposed to ionizing γ-irradiation in single doses of 2, 6 or 10 Gy. Twenty-one days post-irradiation, cell nuclei and collagen production were quantified. Cytotoxicity and indicators of differentiation were measured and compared to unirradiated controls. Radiation with backscatter from titanium significantly reduced the number of hOBs but increased the alkaline phosphatase activity in both types of medium when adjusted to the relative cell number on day 21. Irradiated hOBs on the TiF-surface produced similar amounts of collagen as unirradiated controls when cultured in DM. The majority of osteogenic biomarkers significantly increased on day 21 when the hOBs had been exposed to 10 Gy, while the opposite or no effect was observed after lower doses. High doses reinforced with backscatter from titanium resulted in smaller but seemingly more differentiated subpopulations of osteoblasts.

Keywords: Radiotherapy; osseointegration; osteogenic differentiation; radiation backscatter; titanium implants.

Grants and funding

The study was supported by the Norwegian Cancer Society [Grant Number 6902696] and by an Investigator Initiated Study (IIS) Grant [I-AS-15-050] from Dentsply Sirona Implants.