Biomedical Engineering Reference
In-Depth Information
size-speciic effects of the apatite nano-particles corresponding to
the ultra structure of the enamel. The nanostructured biomimetic
materials expose a large surface to volume ratio and extraordinary
physicochemical properties [18, 28]. An example is casein
phosphopeptide (CPP) stabilized by amorphous calcium phosphate
(ACP) [26]. These casein phosphopeptides have a high afinity to
dental plaque and their incorporation into the oral bioilm provides
a reservoir of calcium for re-mineralization [4]. CPP-ACP decreases
the amount of calcium bridging between the pellicle and adhering
bacteria as well as between the bacteria by interaction with calcium
binding sites. Furthermore, speciic receptor molecules are blocked.
This reduces the general bacterial colonization as demonstrated
in situ
with germanium surfaces treated with CPP-ACP [23]. How-
ever, CPP-ACP does not mimic nano-sized enamel crystallites. Other
biomimetic approaches are based on hydroxyapatite-nanocrystals
resembling the nanostructure of abraded dental enamel crystallites.
Non-aggregated as well as clustered hydroxylapatite nano-crystallite
particles (100 × 10 × 5 nm) adsorb to bacterial surfaces
in vitro
[32]. The adsorbed nano-sized apatite interacts with the bacterial
adhesins, and thus reduces bacterial adherence.
Different types and pharmaceutical forms of nano-hydroxyla-
patite promote re-mineralization and repair of de-mineralized
enamel or micro-sized tooth surface defects [12, 27, 28]. Typically,
these nano-crystallites mimic the size of natural dentinal
hydroxylapatite (20 nm) or enamel apatite (100 nm), sometimes
aggregated as clusters [28]. Different forms of the particles such as
spheroidal or needle like crystallites have been tested and it turned
out that they improve remineralization of artiicial caries better than
sodium luoride typically found in toothpastes [17]. These artiicial
nano-apatites might be supplied during daily oral hygiene measures
using toothpastes, mouth rinsing solutions, chewing gums, etc.
A new biomimetic mineral coating, which progressively ills
and shadows surface scratches, covers, and safeguards the enamel
structure by contrasting the acid and bacteria attacks [17, 27].
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Antimicrobial Effect of Nanometric
Bioactive Glass 45S5
The clinically interesting antimicrobial properties of commercially
available, micron-sized bioactive glass 45S5 have been attributed
