Biomedical Engineering Reference
In-Depth Information
Even after the demineralization of dentin, active types of BMPs bind collagen-rich matrices,
similar to bone (Urist et al., 1973). The decalcified dentin (DDM) was known to be more active
bone-inducing matrix than the calcified dentin (Yeoman & Urist, 1967), and roll type of
decalcified dentin membrane revealed better activity of bone induction (Inoue et al., 1986).
Very interestingly, the demineralized treatment for bone and dentin increased their
osteoinductivity and decreased their antigenesity (Reddi, 1974). These facts are scientifically
very important for the processing procedures of hard tissue-derived graft materials (Kim et
al., 2010; Murata et al, 2010a).
The acid-insoluble dentin matrix (DDM) after demineralization is an organic, absorbable
material with original dentin structures. Human DDM, prepared from vital teeth-origin,
were implanted into the subcutaneous tissue in 4 week-old nude mice, deficient in
immunogenic reactions. The DDM induced bone and cartilage independently at 4 weeks
after the subcutaneous implantation, similar to human DBM (Murata et al., 2010b). The
independent differentiation of bone and cartilage was compatible to our previous study
using ceramic and collagen combined with BMPs (Murata et al., 1998). The acid-insoluble
collagen, DBM and DDM, possess the ability to coagulate platelet-free heparinized, citrated,
and oxalated blood plasmas (Huggins & Reddi., 1973). Clotting constituents become
denatured in contact with the insoluble coagulant proteins. The coagulation action of blood
plasma by DBM and DDM should become advantageous for surgical operations.
Collagenous materials has been commercially available as medical uses for more 30 years.
3. Clinical study of human dentin
3.1 Case 1: Bone augmentation, 48 year-old man
First clinical study was reported at 81st IADR conference, Sweden in 2003 that DDM
autograft had succeeded for bone augmentation (Murata et al., 2003).
The aim of this pioneering study is to observe new bone formation in the tissues obtained
from the dental implant-placed region after the DDM graft for sinus lifting.
Patient
A 48-year-old male presented with missing teeth (#24-#26, #45-#47). Clinical examinations
revealed an atrophied upper jaw in the region (Fig. 3,4). His medical history was
unremarkable.
Surgical procedure 1
Four teeth (#17,#18,#25,#28) were extracted and 2 molars (#17,#18) were stocked at -80
℃
for DDM. His right occlusion was restored using dental implants as the first clinical step
(Fig. 4b).
Preparations of DDM
The autogenous DDM were obtained from non-functional vital teeth (#17, #18) (Fig. 4a). The
molars were crushed by hand-made under the cooling with liquid nitrogen. The crushed
tooth granules were decalcified completely in 0.6N HCl solution. The DDM granules
including cementum were extensively rinsed in cold distilled water, and then freeze-dried
(Murata et al., 2010a).
Surgical procedure 2
Sinus lifting procedure was done using autogenous dry DDM for bone augmentation (Fig.
3). At 5 months after the operation, 3 fixtures (FLIALIT-2®, FRIADENT) were implanted
