Japanese researchers have carried out successful tooth regeneration in a postnatal large-animal model, publishing their findings in this month’s Scientific Reports.
Conventional therapies for restoring the loss of a tooth—due to caries, gum disease or injury—essentially consist of replacing the tooth with artificial material or an osseointegrated dental implant.
A promising alternative approach is whole-organ regeneration technology: a new tooth is grown from bioengineered tooth germ transplanted into the jawbone.
Now Takuo Kuboki from Okayama University and colleagues have demonstrated successful functional tooth restoration via such an approach.
The team used a method that involved the autologous transplantation of bioengineered tooth germ into a canine jawbone; the in vivo artificially created tooth had the structure, composition and physiological characteristics of a natural tooth.
First, they tested whether bioengineered tooth germ does indeed lead to the formation of a proper tooth. They dissected embryonic tooth germ cells and tissues of a dog 55 days prior to birth, and then reconstructed bioengineered tooth germ by means of a technique known as the organ germ method. The germs were then transplanted into mice.
In many cases, the germ resulted after several weeks in tooth-crown formation, featuring both the hard and soft tissues present in natural teeth.
The scientists then performed autologous transplantation experiments. Applying this to their canine model, they extracted deciduous teeth from the jawbone of a 30-day old beagle dog. Tooth germ engineered from the dog’s permanent tooth cell and tissue was then transplanted into the dog’s mandible, resulting in tooth eruption 180 days later.
Micro-CT analysis showed that the developmental process of the bioengineered tooth’s formation in terms of structure and chemical composition was practically identical to that of a natural tooth.
In addition, the response of the regenerated tooth to a mechanical force was found to be consistent with proper physiological functioning of the periodontal ligament.
The researchers concluded: “This study highlights the feasibility of fully functional tooth restoration by autologous transplantation of bioengineered tooth germ.”
