Laser caries detection/laser fluorescence
This is a low-power laser application, which does not raise safety concerns. The
system is commercially available and known as 'Diagnodent'(KaVo). Many workers
have studied it and reported the laser fluorescence system overscores lesions while the
conventional visual method underscores them. The problem with the laser
fluorescence instrument is that it cannot differentiate between caries and
hypomineralisation. Furthermore, staining is interpreted as caries and the presence of
plaque deleteriously affects performance. Therefore, it should only be used as an
adjunct to clinical examination and diagnosis.
Argon laser irradiation as a preventive treatment
At certain settings Nd : YAG laser irradiation of sound enamel has been reported to
increase surface micro-hardness. Some researchers report that argon laser irradiation
produces a surface with enhanced caries resistance. Several authors have studied these
by creating plaque retentive areas on teeth destined to be removed for orthodontic
reasons and recorded the effect that different pre-treatments had prior to 6 weeks of
plaque accumulation. Pre-treatment with an argon laser led to less lesion formation
and improved further if combined with topical fluoride application. The results seem
very impressive but need replication in the long term, in the form of controlled
clinical trials, to determine the significance in a population as a whole instead of
specific artificially created caries prone areas. If proven they may yield a simple non-
invasive and pain free technique for reducing caries susceptibility of enamel.
Resin curing
Argon lasers are able to polymerize composite resins in a shorter time than
conventional light sources. The use of this type of laser has the additional advantage
of increasing the ability of tooth structure to resist cariogenic challenges and may also
increase resistance of the enamel surrounding the polymerized resin. One study also
found that laser polymerization lowered the proportion of non-polymerized monomer
and slightly improved the physical properties of the resin in comparison to visible-
light methods of curing. It is important to remember that resins cured with lasers do
not necessarily have superior physical properties and it is particularly important to
check that the initiators within the resin are activated at the specific wavelength of the
laser. Again there is a paucity of clinical studies to support these concepts.
Laser bleaching
Both carbon dioxide and argon lasers have been suggested as a method of tooth
whitening. There have been no controlled clinical studies and there are concerns
regarding the pulpal safety in connection with carbon dioxide lasers, so the use of this
type of laser is not recommended. In one study an argon ion laser produced less
temperature rise when used to increase the activity of a bleaching gel compared with
conventional quartz tungsten; hence, plasma arc lights may be acceptable.
Enamel etching