Effects of gamma irradiation on the measurement of hepatitis B virus DNA in dentin harvested from chronically infected patients

Abstract

Background: The manufacturing of the demineralized dentin matrix (DDM) has been proven to extensively reduce the presence of human hepatitis B viral DNA (HBV DNA). This study measured and compared HBV DNA in fresh dentin to that in gamma radiation (GR)-sterilized dentin extracted from HBVinfected patients. The application of GR as a means of terminal sterilization is hypothesized to inactivate or eliminate HBV within the dentin matrix.Methods: Dentin from 18 HBV-infected patients was collected and divided into three fragments. The first fragment was unaltered and used as the control group; the remaining two fragments were sterilized with gamma radiation doses of 15 or 25 kGy. DNA was extracted and purified from each fresh (control), and the GR-sterilized (experimental) dentin specimen and HBV DNA copy numbers were evaluated on the basis of the real-time polymerase chain reaction. The copy numbers were used to assess GR efficacy as a means of terminal sterilization for HBV inactivation or elimination.Results: HBV DNA was detected in 66.67% of the fresh dentin specimens. The differences in HBV DNA levels between the fresh dentin and the GR-sterilized dentin were confirmed by the Wilcoxon signed-rank test for the doses of 15 and 25 kGy with P value of 0.012 and 0.010, respectively. Among the twelve HBV-DNA-positive fresh dentin samples, HBV DNA persisted in eleven after GR sterilization, yet the copy number was reduced to <10 (except for a single sample within each experimental group). Conclusions:The results suggest that 15 and 25 kGy of GR significantly reduced the HBV DNA levels in the fresh dentin matrix. Expansion of the possible clinical applications of allogenic grafts with the irradiated DDM will require additional studies, including validation of viral load inactivation to prevent infectious transmission and examination of GR exposure effects on the osteoinductivity of the matrix.

Effect of Gamma Irradiation on the Osteoinductivity of Demineralized Dentin Matrix for Allografts: A Preliminary Study

“…Since DDM does not have vascular channels nor a marrow space [ 51 ], the negative effect of irradiation could be diminished on DDM in comparison to DBM. In addition, the low antigenicity of DDM, due to the acellular nature of dentin, could reduce the irradiation dose required to reduce the risk of viral disease transmission [ 3 , 22 , 54 , 55 ].…”

“…Although viruses show maximum resistance against irradiation, several studies have shown that the hepatitis C virus (HCV) and human immunodeficiency virus (HIV) are completely vulnerable to high doses of radiation [ 20 , 21 ]. In 2020, the effect of gamma irradiation with 15 and 25 kGy was a significant reduction of the HBV DNA levels in the fresh dentin matrix that was harvested from chronically infected patients [ 22 ].…”

“…In addition to the processing procedures of DDM that could inactivate HBV on freshly infected dentin [ 31 ], Ku et al recently reported GR treatment of fresh dentin from hepatitis B virus (HBV)-infected patients at dosages of 15 and 25 kGy. The authors suggested that GR treatment at 15 and 25 kGy is effective in the elimination or inactivation of HBV [ 22 ]. However, the effect of GR on the osteoinductivity of DDM has not been reported yet.…”

A critical analysis of research methods and experimental models to study tooth discolouration from endodontic materials

“…Sterilization using steam, dry heat and ethylene oxide all adversely influence teeth, while gamma sterilization reliably sterilizes teeth without causing changes to their composition or physical properties (Brauer et al, 2008; Rolland et al, 2007). It inactivates viral DNA within teeth and makes the samples safe to handle in the laboratory setting (Ku et al, 2020).…”

In vitro Cell Proliferation Assay of Demineralized Dentin Material Membrane in Osteoblastic MC3T3-E1 Cells

“…The double packing and sterilisation process were conducted using gamma irradiation. 26,28 The present research was approved by Health Research Ethical Clearance Commission, Universitas Airlangga, Faculty of Dental, Number 780/HERCC.FODM/X/2020, and was conducted at the Research Center, Faculty of Dental Medicine, Universitas Airlangga, Surabaya, Indonesia.…”