Biomedical Engineering Reference
In-Depth Information
11.4 BIOACTIVE GLASS IN DENTAL BONE
REGENERATION
The utilisation of bioactive glasses in dentistry is based either on the
ability of the glass to enhance bone, dentine and enamel apatite regener-
ation, or the antimicrobial effect that the dissolution of the glass in body
fluids has on oral microorganisms. Most studies of bioactive glasses in
dental applications have been done with 45S5 glass and S53P4 glass.
Despite the active and ongoing research in the field of bioactive glasses,
their utilisation in dentistry is still modest.
Dental implants require that sufficient bone tissue exists in the jaw
in order to support the anchorage of the implant. After removing the
tooth, the bone in the jaw underneath it starts to resorb, as it is not
mechanically loaded. The thickness of the jawbone can be restored by
grafting the bone with a suitable material. Usually, an autograft, that is,
bone tissue taken from other sites of the same patient, is used to generate
bone growth. The utilisation of autograft obviously requires additional
surgery, which prolongs convalescence. The availability of autograft for
large bone defects is also limited. Bioactive glasses, with their ability to
guide and stimulate new bone growth, are particularly feasible materials
as bone grafts.
One of the first commercial applications of bioactive glasses in den-
tistry was to prevent the resorption of alveolar bone in the jaw after
tooth removal prior to dental implant surgery [7]. Cones of Bioglass
were placed in the fresh cavities that were left after the tooth removal,
and after a few weeks dentures could then successfully be implanted.
Periodontitis, an inflammatory disease caused by microorganisms in
the oral cavity, has also been successfully treated with bioactive glass.
In periodontitis, the supporting tissue around the teeth is infected and
this infection may lead to the loosening of the soft tissue from the tooth,
to bone resorption and, in cases of extensive resorption, to complete
loss of the tooth. Clinical studies of filling bone defects around the root
of the tooth with particles of S53P4 glass suggested that the glass is
a very promising grafting material. Since then, bioactive glass particles
have been used more frequently in alveolar bone healing, for example,
PerioGlas (from NovaBone).
The bone in the lower jaw, the mandible, consists mainly of compact
cortical bone tissue, which can be grafted with biomaterials relatively
easily. The upper jaw, the maxilla, consists of porous cancellous bone
tissue and resorbs rapidly in periodontitis or after removal of the tooth.
