Biomedical Engineering Reference
In-Depth Information
The CPP-ACP literature has been reviewed by several authors [80
82] with the most recent being
a systematic meta-analysis concluding that there is sufficient clinical evidence demonstrating
enamel remineralization and caries prevention by regular use of products containing CPP-ACP
(82). The CPPs stabilize calcium and phosphate ions through the formation of amorphous nanocom-
plexes, which would be expected to enter the porosities of an enamel subsurface lesion and diffuse
down concentration gradients into the body of the subsurface lesion. Once present in the enamel
subsurface lesion, the CPP-ACP would release the weakly bound calcium and phosphate ions which
then deposits into crystal voids [83] . Further, the CPP-ACP nanocomplexes have also been demon-
strated to bind onto the tooth surface and into supragingival plaque to significantly increase the
level of bioavailable calcium and phosphate ion [84] . In all of the remineralization technologies
currently available commercially, the CPP-ACP and CPP-ACFP technology has the most evidence
to support its use.
Except for the nano-HA and CPP-ACP, other nanosized calcium phosphates have also been
considered as remineralization agents due to their unique properties. For nanodimensional DCPA,
decreasing of DCPA particle dimensions were found to increase the Ca 2 1 and PO 4 3 2 ions release
from DCPA-based biocomposites. Nano-DCPA-based biocomposites, possessing both a high
strength and good release of Ca 2 1 and PO 4 3 2 ions, may therefore provide the needed and unique
combination of stress-bearing and caries-inhibiting capabilities suitable for dental applications [85] .
A positive influence of adding nanodimensional
-TCP against acid demineralization and promoted
remineralization of enamel surface was also detected [86] . In another in vitro study, nanosized
amorphous calcium carbonate particles applied twice a day for 20 days promoted remineralization
of artificial white-spot enamel lesions [87] .
Dentine remineralization is clinically significant for the prevention and treatment of dentine car-
ies, root caries, and dentine hypersensitivity. Dentine remineralization is, however, more difficult
than enamel remineralization due to the abundant presence of organic matrix in dentine. An
accepted notion is that dentine remineralization occurs neither by the spontaneous precipitation nor
by the nucleation of mineral on the organic matrix (mainly type I collagen) but by the growth of
residual inorganic crystals in the lesions [88] . Reconstitution and remineralization of dentine using
nanosized bioactive glass particles and betatricalcium phosphate was also tested in vitro, however,
the mechanical properties of original dentine could not be reproduced [89,90] . Fortunately, the bio-
mimetic remineralization scheme provides a proof of concept for the adoption of nanotechnology
as an alternative strategy to remineralization of dentine. Metastable ACP nanoprecursors were gen-
erated when polyacrylic acid was included in the phosphate-containing fluid. The nanoprecursors
were attracted to the acid-demineralized collagen matrix and transformed into polyelectrolyte-
stabilized apatite nanocrystals that assembled along the microfibrils (intrabrillar remineralization)
and surface of the collagen fibrils (interfibrillar remineralization) to achieve dentine remineraliza-
tion [91] . The results revealed that guided tissue remineralization based on nanotechnology is
potentially useful in the remineralization of acid-etched dentine that is incompletely infiltrated by
dentine adhesives, and partially demineralized caries-affected dentine.
β
20.4.3 Nanomaterial in dentin
pulp complex regeneration
Restorative dentistry is looking for techniques and materials to regenerate the dentin
pulp complex
in a biological manner. This showed the great potential in the treatment of our most common oral
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