Biomedical Engineering Reference
In-Depth Information
removal of a tooth; (ii) to heal and regenerate bone defects around a
tooth root and metal implant; (iii) to regenerate bone before denture
placement; and (iv) to fill bone voids in implant placement. All these
applications have one thing in common - the proven capability of the
glass to guide and support bone growth by HA precipitation on the glass
surface and the surrounding tissue. Commercial products based on melt-
derived glasses, Bioglass (e.g. PerioGlas), BonAlive and StronBone
, are
available for bone regeneration.
11.5 TREATMENT OF HYPERSENSITIVE TEETH
A common symptom of hypersensitivity is sharp pain when the tooth
is suddenly subjected to hot, cold, bitter and sweet drinks and food.
Inflammatory reactions of the gum around the teeth may lead to exposed
dentine. Dentine consists of narrow 1-2
m long tubules that lead to
the pulp of the tooth and sensitive nerve endings. Fluid flow in the
opened dentine tubules is assumed to be the reason for hypersensitive
teeth. Since the first results of using S53P4 glass in the treatment of
hypersensitive teeth were published, several other studies have been
conducted on the effect of bioactive glass and glass-ceramics to treat
dentine hypersensitivity [9].
Sensodyne Repair & Protect (GlaxoSmithKline, UK) contains a fine
particulate of Bioglass that reduces hypersensitivity (see Figure 2 in
colour section). Trials based on brushing with NovaMin ® indicate that
the glass particles attach to the dentine, release ions and raise pH,
causing precipitation of HCA over the tubule ends, blocking the tubules.
Figure 11.4 shows dentine tubules and how the bioactive glass particles
attach to the dentine and then produce HCA [10]. When the oral area
is exposed to acidic environments such as carbonated drinks and fruit
juices, it is likely that the HA crystals formed from the treatment with the
toothpaste dissolve easily [11]. Tailoring the composition of the glass to
dissolve fluorapatite crystals instead of HCA crystals has been reported to
give a more chemically stable treatment against dentine hypersensitivity
[11]. Similar results were observed when dentine was treated with a
paste containing fine-grained S53P4 glass (diameter
μ
m).
Bioglass in toothpaste also aids in remineralisation of tooth enamel
after acid leaching or bleaching treatments [12, 13]. Also, bioactive
glasses can be utilised to strengthen the dentine tubules during the treat-
ment of enamel and root caries. Stronger dentine increases the fracture
strength of the restored tooth. After removing the carious tissue, the
cleaned cavity is filled temporarily with a paste or suspension containing
20
μ
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