Laser Use in Dentistry
Laser Use in Dentistry
Lasers have been used in dentistry since 1994 to treat a number of dental problems. But, despite FDA approval, no laser system has received the American Dental Association's (ADA) Seal of Acceptance. That seal assures dentists that the product or device meets ADA standards of safety and efficacy, among other things. The ADA, however, states that it is cautiously optimistic about the role of laser technology in the field of dentistry. These lasers are different from the cold lasers used in phototherapy for the relief of headaches, pain, and inflammation.
Still, some dentists are using lasers to treat:
- Tooth decay. Lasers are used to remove decay within a tooth and prepare the surrounding enamel for receipt of the filling. Lasers are also used to "cure" or harden a filling.
- Gum disease. Lasers are used to reshape gums and remove bacteria during root canal procedures.
- Biopsy or lesion removal. Lasers can be used to remove a small piece of tissue (called a biopsy) so that it can be examined for cancer. Laser are also used to remove lesions in the mouth; and relieve the pain ofcanker sores.
- Teeth whitening. Lasers are used to speed up the in-office teeth whitening procedures. A peroxide bleaching solution, applied to the tooth surface, is "activated" by laser energy, which speeds up of the whitening process.
How Do Lasers Work in Dentistry?
All lasers work by delivering energy in the form of light. When used for surgical and dental procedures, the laser acts as a cutting instrument or a vaporizer of tissue that it comes in contact with. When used for "curing" a filling, the laser helps to strengthen the bond between the filling and the tooth. When used in teeth whitening procedures, the laser acts as a heat source and enhances the effect of tooth beaching agents.
What Are the Pros and Cons of Using a Laser in Dentistry?
Pros
Compared to the traditional dental drill, lasers:
- May cause less pain in some instances, therefore, reducing the need for anesthesia
- May reduce anxiety in patients uncomfortable with the use of the dental drill
- Minimize bleeding and swelling during soft tissue treatments
- May preserve more healthy tooth during cavity removal
Cons
The disadvantages of lasers are that:
- Lasers can't be used on teeth with fillings already in place.
- Lasers can't be used in many commonly performed dental procedures. For example, lasers can't be used to fill cavities located between teeth, around old fillings, and large cavities that need to be prepared for a crown. In addition, lasers cannot be used to remove defective crowns or silver fillings, or prepare teeth for bridges.
- Traditional drills may still be needed to shape the filling, adjust the bite, and polish the filling even when a laser is used.
- Lasers do not eliminate the need for anesthesia.
- Laser treatment tends to be more expensive since the cost of the laser is much higher than a dental drill. Lasers can cost between $39,000 and $45,000 compared to about $600 for a standard drill.
Dentists use lasers to remove tooth decay, treat gum disease, biopsy tissue, and whiten teeth. Oftentimes, lasers cause less pain than traditional dental work, plus, they minimize bleeding and swelling. Unfortunately, lasers can't be used on teeth that already have fillings.
The current status of laser applications in dentistry
LJ Walsh*
Abstract
A range of lasers is now available for use in
dentistry. This paper summarizes key current and
emerging applications for lasers in clinical practice.
A major diagnostic application of low power lasers
is the detection of caries, using fluorescence elicited
from hydroxyapatite or from bacterial by-products.
Laser fluorescence is an effective method for
detecting and quantifying incipient occlusal and
cervical carious lesions, and with further refinement
could be used in the same manner for proximal
lesions. Photoactivated dye techniques have been
developed which use low power lasers to elicit a
photochemical reaction. Photoactivated dye
techniques can be used to disinfect root canals,
periodontal pockets, cavity preparations and sites of
peri-implantitis. Using similar principles, more
powerful lasers can be used for photodynamic
therapy in the treatment of malignancies of the oral
mucosa. Laser-driven photochemical reactions can
also be used for tooth whitening. In combination
with fluoride, laser irradiation can improve the
resistance of tooth structure to demineralization,
and this application is of particular benefit for
susceptible sites in high caries risk patients. Laser
technology for caries removal, cavity preparation
and soft tissue surgery is at a high state of
refinement, having had several decades of
development up to the present time. Used in
conjunction with or as a replacement for traditional
methods, it is expected that specific laser
technologies will become an essential component of
contemporary dental practice over the next decade.
Key words: Lasers, dental applications, débridement,
photosensitization, resin curing.
(Accepted for publication 6 February 2003.)
of the usefulness of lasers in the armamentarium of the
modern dental practice, where they can be used as an
adjunct or alternative to traditional approaches.
Traditionally, lasers have been classified according to
the physical construction of the laser (e.g., gas, liquid,
solid state, or semiconductor diode), the type of
medium which undergoes lasing (e.g., Erbium: Yttrium
Aluminium Garnet (Er:YAG)) (Table 1), and the degree
of hazard to the skin or eyes following inadvertent
exposure (Table 2). Lasers have been available
commercially for use in dental practice in Australia
since 1990, and the currently available systems
represent a high state of technical refinement in terms
of both performance and user features.
The purpose of this paper is to provide an overview
of various laser applications which have been
developed for dental practice, and to discuss in more
detail several key clinical applications which are
attracting a high level of interest.
Diagnostic laser applications
Low power laser energy has found numerous uses in
diagnosis, both in clinical settings (Table 3) and in
dental research (Table 4). By way of background, low
power lasers operate typically at powers of 100
milliwatts or less, and may produce energy in the visible
spectrum (400-700nm wavelength), or in the ultraviolet
(200-400nm), or near infrared regions (700-1500nm).
At the present time, there are few purpose built low
power lasers for the middle infrared (1500-4000nm) or
far infrared regions (4000-15000nm). Rather, lasers
operating in the middle and far-infrared regions are
used in health care primarily for hard and soft tissue
procedures.
Laser fluorescence systems for detection of dental
caries have been particularly popular in Australia. The
original technique employed visible blue light from the
argon laser, relying on the lack of fluorescence from
carious enamel and dentine to demonstrate the
presence of the lesion. Subsequent development of the
technique allowed visible red laser light from a
semiconductor diode laser to be used to elicit
fluorescence from bacterial deposits, and from calculus.
Combining a detection system with a therapeutic laser
has allowed automated removal of subgingival calculus
INTRODUCTION
The past decade has seen a veritable explosion of
research into the clinical applications of lasers in dental
practice, and the parallel emergence of organizations to
support laser dentistry with an international focus.
Once regarded as a complex technology with limited
uses in clinical dentistry, there is a growing awareness
*Professor of Dental Science, School of Dentistry, The University of
Queensland.
Australian Dental Journal 2003;48:(3):146-155
R E V I E Wfrom teeth and dental implants, a point discussed in
further detail below.
For detection of dental caries in pits and fissures,
laser fluorescence offers greater sensitivity than
conventional visual and tactile methods.
1,2
The
technique is also well suited to smooth surface lesions
on cervical surfaces of teeth,
3,4
and to recognition of
caries beneath clear fissure sealants.
5
Detection of
proximal lesions is technically more difficult, and in
this setting, argon laser-induced fluorescence offers a
valuable adjunct to conventional methods.
6-9
The
differential water content of early fissure caries and
sound occlusal enamel has also led to the development
of methods using the carbon dioxide laser to reveal
such lesions,
10-12
and to modify the fissure system to
increase resistance to future carious attack.
11
Two key advantages of laser-based systems are their
high sensitivity, and the lack of attendant risks of
ionizing radiation. This has allowed their frequent use
for monitoring lesions of dental caries and dental
erosion.
13-16
Extension of the principles of laser
fluorescence from the visible to the near infrared and
terahertz portions of spectrum opens the possibility for
more detailed analysis of the internal composition of
the tooth.
17
Moreover, the use of dyes in conjunction
with laser fluorescence holds promise for using the
method for delineating cavitated from non-cavitated
lesions in sites of poor clinical access, such as
approximal surfaces.
18,19
Bacterial porphyrins in dental calculus give a strong
fluorescence signal,
20
which can be used to control
lasers used for scaling. The same principle could be
applied to lesions of dental caries, where a targeting
laser could induce fluorescence and provide feedback to
the user as to the presence of residual bacteria (i.e., the
presence of infected carious dentine), and could also
control the action of a pulsed laser to achieve
automated caries removal. There are already data on
the spectral changes which occur during infrared laser
treatment of enamel and dentine
21,22
which could
similarly be applied clinically when assessing the
presence or absence of carious tooth structure during
laser-based cavity preparation.
Photoactivated dye disinfection using lasers
Low power laser energy in itself is not particularly
lethal to bacteria, but is useful for photochemical
activation of oxygen-releasing dyes. Singlet oxygen
released from the dyes causes membrane and DNA
damage to micro-organisms. The photoactivated dye
(PAD) technique can be undertaken with a range of
visible red and near infrared lasers, and systems using
low power (100 milliwatt) visible red semiconductor
diode lasers and tolonium chloride (toluidine blue) dye
are now available commercially (Fig 1). The initial
work which demonstrated the PAD technique used
helium-neon lasers.
23
However, such units have been
surpassed with high efficiency diode lasers which
operate at the same wavelength.
The PAD technique has been shown to be effective
for killing bacteria in complex biofilms, such as
subgingival plaque, which are typically resistant to the
action of antimicrobial agents.
24-26
It can be used
effectively in carious lesions, since visible red light
transmits well across dentine,
27
and can be made
species-specific by tagging the dye with monoclonal
147
Australian Dental Journal 2003;48:3.
Table 1. Common laser types used in dentistry
Laser type Construction Wavelength(s) Delivery system(s)
Argon Gas laser 488, 515nm Optical fibre
KTP Solid state 532nm Optical fibre
Helium-neon Gas laser 633nm Optical fibre
Diode Semiconductor 635, 670, 810, Optical fibre
830, 980nm
Nd:YAG Solid state 1064nm Optical fibre
Er,Cr:YSGG Solid state 2780nm Optical fibre
Er:YAG Solid state 2940nm Optical fibre,
waveguide,
articulated arm
CO2 Gas laser 9600, 10600nm Waveguide,
articulated arm
Table 2. Laser classification according to potential
hazards
Class Risk Example
I Fully enclosed system Nd:YAG laser welding system
used in a dental laboratory
II Visible low power laser Visible red aiming beam of a
protected by the blink reflex surgical laser
IIIa Visible laser above No dental examples
1 milliwatt
IIIb Higher power laser unit Low power (50 milliwatt)
(up to 0.5 watts) which diode laser used for
may or may not be visible. biostimulation
Direct viewing hazardous
to the eyes
IV Damage to eyes and skin All lasers used for oral surgery,
possible. Direct or indirect whitening, and cavity
viewing hazardous to preparation
the eyes
Table 3. Diagnostic laser applications for clinical practice
Argon Helium-neon Diode Diode CO2
488nm 633nm 633nm 655nm 10600nm
Laser fluorescence detection of dental caries ✔ ✔
Laser fluorescence detection of subgingival calculus ✔
Detection of fissure caries lesions by optical changes ✔
Laser doppler flowmetry to assess pulpal blood flow ✔ ✔
Scanning of phosphor plate digital radiographs ✔
Scanning of conventional radiographs for teleradiology ✔148 Australian Dental Journal 2003;48:3.
antibodies.
28
Photoactivated dye can be applied
effectively for killing Gram-positive bacteria (including
MRSA), Gram-negative bacteria, fungi and viruses.
29,30
Major clinical applications of PAD include
disinfection of root canals, periodontal pockets, deep
carious lesions, and sites of peri-implantitis.
31,32
In such
locations, PAD does not give rise to deleterious thermal
effects,
33
and adjacent tissues are not subjected to
bystander thermal injury. Photoactivated dye treatment
does not cause sensitization and killing of adjacent
human cells such as fibroblasts and keratinocytes.
34
Neither the dye nor the reactive oxygen species
produced from it are toxic to the patient. Tolonium
chloride is used in high concentrations for screening
patients for malignancies of the oral mucosa and
oropharynx,
35,36
and does not exert toxic effects at the
low concentrations used in the PAD technique.
Moreover, residual reactive oxygen species are rapidly
dealt with by the enzyme catalase, which is present in
all tissues and in the peripheral circulation,
37
and by
lactoperoxidase, which is a normal component of
saliva.
Photodynamic therapy
A more powerful laser-initiated photochemical
reaction is photodynamic therapy (PDT), which has
been employed in the treatment of malignancies of the
oral mucosa, particularly multi-focal squamous cell
carcinoma. As in PAD, laser-activation of a sensitizing
dye in PDT generates reactive oxygen species. These in
turn directly damage cells and the associated blood
vascular network, triggering both necrosis and
apoptosis.
38
Of interest, while direct effects of PDT destroy the
bulk of tumour cells, there is accumulating evidence
that PDT activates the host immune response, and
promotes anti-tumour immunity through the activation
of macrophages and T lymphocytes.
37
For example,
there is direct experimental evidence for photodynamic
activation of the production of tumour necrosis factoralpha,
39
a key cytokine in host anti-tumour immune
responses.
Clinical studies have reported positive results for
PDT treatment of carcinoma-in-situ and squamous cell
carcinoma in the oral cavity, with response rates
approximating 90 per cent.
40,41
The treated sites
characteristically show erythema and oedema, followed
by necrosis and frank ulceration. The ulcerated lesions
typically take up to eight weeks to heal fully, and
supportive analgesia is required in the first few weeks.
Other than short-term photosensitivity, the treatment is
tolerated well.
39
Other photochemical laser effects
The argon laser produces high intensity visible blue
light (488nm) which is able to initiate photopolymerization of light-cured dental restorative
materials which use camphoroquinone as the
photoinitiator.
42-44
The temperature increase at the level
of the dental pulp is much less with argon laser curing
than when conventional quartz tungsten halogen lamp
units are used.
45,46
Argon laser radiation is also able to
alter the surface chemistry of both enamel and root
surface dentine,
47,48
which reduces the probability of
recurrent caries. This clinical benefit is arguably more
important than the reduced curing time and improved
depth of cure achieved with the argon laser.
A further photochemical effect produced by high
intensity green laser light is photochemical bleaching
(Table 5). This effect relies upon specific absorption of
a narrow spectral range of green light (510-540nm)
into chelate compounds formed between apatites,
Table 4. Diagnostic laser applications used as research tools
Nd:YAG Er:YAG Argon Helium-neon Diode
1064nm 2940nm 488 and 515nm 633nm 633 and 670nm
Raman spectroscopic analysis of tooth structure ✔
Terahertz imaging of internal tooth structure ✔
Breakdown spectroscopic analysis of tooth structure ✔ ✔
Confocal microscopic imaging of soft and hard tissues ✔
Flow cytometric analysis of cells and cell sorting ✔
Profiling of tooth surfaces and dental restorations ✔ ✔
Fig 1. Laser system for photo-activated dye therapy, which uses a
diode laser (635nm) and tolonium chloride dye (SaveDent, Asclepion
Meditec, Fife, UK).
Table 5. Laser-enhanced tooth whitening
Argon KTP Diode CO2
515nm 532nm 810-980nm 10600nm
Photochemical bleaching ✔ ✔
Photothermal bleaching ✔ ✔porphyrins, and tetracycline compounds.
49
The argon
laser (515nm) and potassium titanyl phosphate (KTP)
laser (532nm) can both be used for photochemical
bleaching, since their wavelengths approximate the
absorption maxima of these chelate compounds (525-
530nm).
50
Argon and KTP lasers can achieve a positive
result in cases which are completely unresponsive to
conventional photothermal ‘power’ bleaching (Fig 2).
Laser applications in the dental laboratory
There is a range of laboratory-based laser
applications (Table 6). Laser holographic imaging is a
well established method for storing topographic
information, such as crown preparations, occlusal
tables, and facial forms. The use of two laser beams
allows more complex surface detail to be mapped using
interferometry,
51,52
while conventional diffraction
gratings and interference patterns are used to generate
holograms and contour profiles.
53-56
Laser scanning of casts can be linked to
computerized milling equipment for fabrication of
restorations from porcelain and other materials. An
alternative fabrication strategy is to sinter ceramic
materials, to create a solid restoration from a powder
of alumina or hydroxyapatite.
57
The same approach can
be used to form complex shapes from dental wax and
other materials which can be sintered, such that these
can then be used in conventional ‘lost wax’ casting. A
variation on this theme is ultraviolet (helium-cadmium)
laser-initiated polymerization of liquid resin in a
chamber, to create surgical templates for implant
surgery and major reconstructive oral surgery. These
templates can be coupled with laser-based positioning
systems for complex reconstructive and orthognathic
surgical procedures.
Laser procedures on dental hard tissues
Cavity preparation using lasers has been an area of
major research interest since lasers were initially
developed in the early 1960s. At the present time,
several laser types with similar wavelengths in the
middle infrared region of the electromagnetic spectrum
are used commonly for cavity preparation and caries
removal. The Er:YAG, Er:YSGG and Er,Cr:YSGG lasers
operate at wavelengths of 2940, 2790, and 2780nm,
respectively. These wavelengths correspond to the peak
absorption range of water in the infrared spectrum
(Fig 3), although the absorption of the Er:YAG laser
(13,000cm-1
) is much higher than that of the Er:YSGG
(7000cm-1
) and Er,Cr:YSGG (4000cm-1
)
58-60
Since all
three lasers rely on water-based absorption for cutting
enamel and dentine, the efficiency of ablation
(measured in terms of volume and mass loss of tooth
structure for identical energy parameters) is greatest for
the Er:YAG laser.
58,60
These laser systems can be used for effective caries
removal and cavity preparation without significant
thermal effects, collateral damage to tooth structure, or
patient discomfort.
61-64
Normal dental enamel contains
sufficient water (approximately 12 per cent by volume)
that a water mist spray coupled to an Er-based laser
Australian Dental Journal 2003;48:3. 149
Fig 2. KTP laser photochemical bleaching. A. Initial clinical
appearance of the dentition in a 9-year-old patient with intense
discolouration of the incisor teeth caused by prolonged childhood
illnesses and associated medications. B. The situation immediately
after three 60-minute appointments of power bleaching using a
conventional quartz tungsten halogen curing lamp and 35 per cent
hydrogen peroxide gel. The incisal enamel shade has improved
somewhat, but the areas of discolouration at the gingival third are
unchanged. The arrow indicates a residue of the protective gingival
dam. C. Clinical appearance immediately after one session of
photochemical bleaching using the KTP laser and proprietary
alkaline hydrogen peroxide (Smartbleach ®) gel. The laser treatment
was targeted to the gingival third. The patient and her parents were
pleased with the immediate post-operative result and did not request
any additional treatment.150 Australian Dental Journal 2003;48:3.
system can achieve effective ablation at temperatures
well below the melting and vapourization temperatures
of enamel.
61
Er-based dental lasers can also be used to
remove resin composite resin and glass-ionomer cement
restorations, and to etch tooth structure (Fig 4).
A characteristic operating feature of Er-based laser
systems is a popping sound when the laser is operating
on dental hard tissues. Both the pitch and resonance of
this sound relate to the propagation of an acoustic
shock wave within the tooth, and vary according to the
presence or absence of caries. This feature assists the
user in determining that caries removal is complete.
66
In
contrast to the popping sound during caries removal,
one current generation Er,Cr:YSGG laser system creates
a loud snapping sound even when not in contact with
any structure in the mouth. This seeming paradox can
be explained by an effect termed ‘plasma de-coupling’
of the beam, in which incident laser energy heats the air
and water directly in front of the laser handpiece. In the
Er,Cr:YSGG laser, this is done intentionally in order to
deliver energy onto the rear surface of atomized water
molecules, with the aim of accelerating them to a higher
speed (so-called ‘HydroKinetic cutting’).
67
Detailed
studies of the cutting mechanisms of Er:YAG and
Er,Cr:YSGG lasers have revealed that the mechanism
by which enamel is removed is basically the same for
both laser systems, namely explosive subsurface
expansion of interstitially trapped water.
65
The same
investigations also failed to show Er,Cr:YSGG laser
cutting of a variety of materials which were free of
water, which the authors stated was ‘contradictory to
the existence of the hydrokinetic phenomenon’.
65
An important theoretical extension to the principle
of water-based laser ablation of tooth structure is the
recently described effect of ‘laser abrasion’, in which
Er:YAG laser energy is used to accelerate the movement
of particles of sapphire 30-50 micrometers in diameter
in aqueous suspension. As in air abrasion, the impact of
these particles causes brittle splitting, resulting in tooth
substance removal. In the laser abrasion method, high
speed photography has documented particle velocities
in the range of 50-100 metres per second, which enable
a rate of enamel removal ‘higher than that of high speed
turbines’ with a very low volume of abrasive particles.
68
This technique could be employed with current
generation lasers once a suitable dispensing system for
the suspension of particles has been developed. As well
as the potential of even more rapid cutting rates than
conventional rotary instrumentation, laser abrasion
offers the promise of laser-based cutting of structures
which are not otherwise amenable to this, such as
ceramic restorations.
Intensive research over the past three decades on
other non-Erbium laser-based cavity preparation
systems has yet to be translated to direct clinical
application. To date, alternative laser systems,
including super-pulsed CO2, Ho:YAG, Ho:YSGG,
Nd:YAG, Nd:NLF, diode lasers and excimers, have not
proven feasible for use for cavity preparation in general
practice settings.
Other than caries removal, this is a range of other
well established laser hard tissue procedures include
desensitization of cervical dentine (using Nd:YAG,
Er:YAG, Er,Cr:YSGG CO2, KTP, and diode lasers),
laser analgesia (using Nd:YAG, Er:YAG, and
Er,Cr:YSGG lasers), laser-enhanced fluoride uptake
(using Er:YAG, Er,Cr:YSGG, CO2, argon, and KTP
lasers). Furthermore, there is a considerable range of
periodontal procedures (Table 7), and endodontic
procedures (Table 8) which can be undertaken with
lasers as an alternative to conventional approaches.
Soft tissue laser procedures
There are numerous soft tissue procedures which can
be performed with lasers.
69-71
Two key features of these
are reduced bleeding intra-operatively and less pain
post-operatively compared to conventional techniques
such as electrosurgery. The degree of absorption in key
tissue components dictates the type of effect gained by
the laser on soft tissues, and in this regard the content
of water and haemoglobin in oral tissues is important
Table 6. Laser applications in the dental laboratory
Helium neon Diode Nd:YAG CO2 Helium-Cadmium
633nm 635nm 1064nm 10600nm 300nm
Scanning of models for orthodontics or holographic storage ✔ ✔
Scanning of crown preparations for CAD-CAM ✔ ✔
Welding of metals (Co:Cr, titanium) ✔
Sintering of ceramics ✔
CAD-sintering fabrication ✔
CAD-polymer fabrication of splints or surgical models ✔
Cutting of ceramics ✔
Fig 3. The absorption curve of water in the middle infrared region.
Data on the vertical axis are units of absorption, while the horizontal
axis shows wavelength in micrometers. The plot shows the position
of two laser wavelengths used for cavity preparation: Er,Cr:YSGG
2.78 micrometers, and Er:YAG 2.94 micrometers. The figure is based
on data from reference 59.
Er,Cr:YSGG
Er:YAG
14000
12000
10000
8000
6000
4000
2000
0
2.6 2.65 2.7 2.75 2.8 2.85 2.9 2.95 3 3.05 3.1 3.15 3.2 3.25 3.3for the efficient absorption of many commonly used
dental lasers.
72
Certain procedures in patients with
bleeding disorders are better suited to lasers with
greater haemostatic capabilities (Table 9). Examples of
simple soft tissue procedures are presented in Fig 5.
CONCLUSIONS
Laser technology for caries detection, resin curing,
cavity preparation and soft tissue surgery is at a high
state of refinement, having had several decades of
development up to the present time. This is not to say
that further major improvements cannot occur. Indeed,
as is in the case with laser abrasion, the fusion of
concepts from differing technologies may open the
door to novel techniques and treatments. The field of
laser-based photochemical reactions holds great
promise for additional applications, particularly for
targeting specific cells, pathogens or molecules. A
further area of future growth is expected to be the
combination of diagnostic and therapeutic laser
techniques in the one device, for example the detection
and removal of dental caries or dental calculus. For
Australian Dental Journal 2003;48:3. 151
Fig 4. Restorative procedures using the Er:YAG laser, in anxious dental patients, without local anesthesia. The Er:YAG laser was used with a
non-contact handpiece. A. Pre-operative appearance of a 22-year-old male with salivary dysfunction, and associated cervical and approximal
caries. B. Areas of caries and defective resin composite have been removed. The intense white appearance of the margins is typical of laser etching.
C. The restored teeth immediately post-operatively. The etched appearance of the margins disappears once bonding resin has been placed.
D. 30-year-old female patient with areas of hypoplastic enamel. E. The enamel surface has been ‘peeled’ using a series of pulses from the laser.
F. The two areas have been restored with resin composite. G. 65-year-old female patient undergoing anti-cancer chemotherapy, with recurrent
caries at the margins of several restorations. H. Areas of caries and undermined resin composite have been removed. I. The cavity preparations
have been restored.152 Australian Dental Journal 2003;48:3.
example, an ‘autopilot’ system for subgingival
d´ebridement has been developed (for detailed review,
see ref 73), and the potential exists to extend this
concept further.
There is a large research effort internationally
focused on developing new laser applications for dental
practice, and each year several large meetings are held
which bring together this research. Examples include
the International Society for Lasers in Dentistry (ISLD),
the European Society for Oral Laser Applications
(ESOLA), and the Academy of Laser Dentistry (ALD).
With the further development of laser dentistry as an
area of clinical pursuit, there will be considerable
opportunity for clinicians to become involved in these
research meetings and in specific research projects. The
Australasian region has played a substantial role in the
development of hard tissue laser applications,
74,75
and
this level of involvement is expected to continue in the
future, as various research groups examine uses for
lasers in conjunction with or as a replacement for
traditional methods.
There is little argument that over recent years the use
of lasers in dentistry in Australia has moved beyond
academic centres and specialist units into the
mainstream of general practice. Looking to the future,
it is expected that specific laser technologies will
become an essential component of contemporary dental
practice over the next decade.
ACKNOWLEDGMENTS
I thank the dental practitioners who have referred
patients to the Laser Clinic over the past 12 years, and
the numerous staff and students who have contributed
to the dental laser research programme at the
University of Queensland.
REFERENCES
1. Shi XQ, Welander U, Angmar-Månsson B. Occlusal caries
detection with KaVo DIAGNOdent and radiography: an in vitro
comparison. Caries Res 2000;34:151-158.
2. Lussi A, Megert B, Longbottom C, Reich E, Francescut P. Clinical
performance of a laser fluorescence device for detection of
occlusal caries lesions. Eur J Oral Sci 2001;109:14-19.
3. Shi XQ, Tranaeus S, Angmar-Månsson B. Validation of
DIAGNOdent for quantification of smooth-surface caries: an in
vitro study. Acta Odontol Scand 2001;59:74-78.
4. Shi XQ, Tranaeus S, Angmar-Månsson B. Comparison of QLF
and DIAGNOdent for quantification of smooth surface caries.
Caries Res 2001;35:21-26.
Table 7. Periodontal laser procedures
Er:YAG Er,Cr:YSGG KTP Argon 488 Diode Nd:YAG Helium-neon Diode 635, CO2
2940nm 2780nm 532nm and 515nm 810-980nm 1064nm 633nm 670 or 830nm 10600nm
Calculus removal ✔
Periodontal pocket
disinfection ✔ ✔ ✔ ✔ ✔ ✔
Photoactivated dye
disinfection of
pockets ✔ ✔
De-epithelialization to
assist regeneration ✔ ✔ ✔
Table 8. Endodontic laser procedures
CO2
Erbium:YAG Er,Cr:YSGG KTP Argon 488 Diode Nd:YAG Helium-neon Diode 635,
10600nm 2940nm 2780nm 532nm and 515nm 810-980nm 1064nm 633nm 670, or 830nm
Direct pulp capping ✔ ✔
Drying of the
root canal ✔ ✔ ✔
Removal of
smear layer ✔ ✔
Root canal
disinfection ✔ ✔ ✔ ✔ ✔ ✔
Photoactivated dye
disinfection of pockets ✔ ✔
Table 9. Surgical laser applications
Er:YAG 2940nm Er,Cr:YSGG CO2 KTP Diode Argon 488 Nd:YAG 1064nm
(least haemostasis) 2780nm 10600nm 532nm 810-980nm and 515nm (most haemostatis)
Minor soft
tissue surgery ✔ ✔ ✔ ✔ ✔ ✔
Major soft
tissue surgery ✔
Surgical treatment
of large
vascular lesions ✔
Bone cutting ✔ ✔
Implant exposure
with bone removal ✔ ✔ ✔5. Takamori K, Hokari N, Okumura Y, Watanabe S. Detection of
occlusal caries under sealants by use of a laser fluorescence
system. J Clin Laser Med Surg 2001;19:267-271.
6. Bjelkhagen H, Sundström F, Angmar-Månsson B, Ryden H. Early
detection of enamel caries by the luminescence excited by visible
laser light. Swed Dent J 1982;6:1-7.
7. Angmar-Månsson B, ten Bosch JJ. Optical methods for the
detection and quantification of caries. Adv Dent Res 1987;1:14-
20.
8. Hafström-Bjorkman U, Sundström F, Angmar-Månsson B. Initial
caries diagnosis in rat molars, using laser fluorescence. Acta
Odontol Scand 1991;49:27-33.
9. Hafström-Bjorkman U, Sundström F, de Josselin de Jong E,
Oliveby A, Angmar-Månsson B. Comparison of laser fluorescence
and longitudinal microradiography for quantitative assessment of
in vitro enamel caries. Caries Res 1992;26:241-247.
10. Longbottom C, Pitts NB. CO2
laser and the diagnosis of occlusal
caries: in vitro study. J Dent 1993;21:234-239.
Australian Dental Journal 2003;48:3. 153
Fig 5. Soft tissue procedures using middle and far infrared lasers. A. Pre-operative clinical appearance of a 22-year-old female with marked gingival
overgrowth from nifedipine and cyclosporin. The patient has received a kidney transplant, is immuno-suppressed, and has a bleeding tendency.
B. the immediate post-operative appearance following gingivoplasty with the carbon dioxide laser. Complete haemostasis is maintained during the
procedure. C. Initial clinical appearance of a 16-year-old female patient with marked gingival overgrowth, which has obscured the orthodontic
brackets and caused the cessation of fixed orthodontic treatment. D. Immediate post-operative view of quadrant 1 following gingival recontouring
with the carbon dioxide laser. E. Immediate post-operative view of quadrant 2 following recontouring with the Er:YAG laser in contact mode.
Note the different appearance of the tissues compared to quadrant 1. Both segments were treated at the same appointment. F and G. Clinical
appearance of the two sites two weeks following surgery. The tissue contours are identical to those determined at the time of surgery
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