Reliability of acellular decalcified and decalcified teeth as bone graft material: an experimental and pathological study in rats.

OBJECTIVE

The present study aimed to investigate the reliability of acellular decalcified teeth in the development of bone scaffolds and in bone regeneration in rats.

METHODS

(1) Forty-eight human teeth were divided into two groups in vitro: twenty-four were decalcified, while the remaining twenty-four were decalcified and decellularized, following which a conventional scanning-electron microscope analysis was performed. (2) In another experiment, six male SD rats aged 10-12 weeks were selected, then decalcified and acellular decalcified teeth were embedded subcutaneously in the abdomen of the rats. After 4 weeks, the rats were sacrificed for H-E staining and immunohistochemical staining to observe the inflammatory reaction around the two materials. (3) In the ectopic osteogenesis experiment, bone defects were simulated in bilateral craniotectal areas of 12 male SD rats (age 10-12 weeks), following which acellular decalcified teeth were implanted in the right bone defect. The non-implanted left side was used as blank control. At week 4 and week 8, 6 rats were randomly selected for execution, complete specimens were obtained, and micro-CT scan was performed to compare the bone mass from gross morphology. H-E staining was performed at 4 and 8 weeks to observe the surrounding inflammatory response and immunohistochemistry was performed at 8 weeks to observe the degree of new bone formation. SPSS 23.0 software package was used for statistical processing.

RESULTS

(1) Under scanning electron microscope, cells in the teeth subjected to acellular decalcification completely disappeared, leaving only inorganic scaffolds. (2) After 4 weeks, the amount of inflammatory reaction in the tissues surrounding acellular decalcified teeth was significantly lower than that in the tissues surrounding decalcified teeth. (3) After four and eight weeks, the amount of bone formation in the bone defects was significantly higher in rats implanted with acellular decalcified teeth than in those in the blank control group (P<0.05). After four and eight weeks, hematoxylin-eosin staining revealed that the degree of inflammatory response was similar around acellular decalcified teeth and blank controls. Immunohistochemistry indicated that the osteocalcin levels were significantly higher around acellular decalcified teeth than that around blank controls.

CONCLUSION

Acellular decalcified teeth show significantly decreased inflammatory reaction, better biocompatibility, better osteogenic potential, and better plasticity than decalcified teeth alone.