Lasers for Dental
Keywords:
Lasers for Dental,
dental tips, Time:29-06-2016
Conventional dentistry involves using rigid metal or diamond instruments to drill, cut, or
abrade hard and soft tissues. Traditional dental treatment is recognized as the process of
removing infected or pathologic tissue by either drilling or cutting away the diseased
component.2 Dental lasers can be used to cut, incise, and ablate hard and soft tissues. The
inherent properties of laser light—such as selective absorption, coagulation,
sterilization, and stimulatory effects on vital structures—make lasers the treatment of
choice in certain clinical scenarios.
Proper clinical technique is extremely important when lasing a patient’s oral tissues. It
is strongly recommended that the operator use proper magnification and illumination to assess
the treatment’s progress accurately and determine that photothermal ablation is occurring.
A definitive color change will be observed at the initial moment of tissue ablation; at that
point, the clinician should move the laser tip in a slow and deliberate “paint
brushing” motion that corresponds to the patient’s specific tissues, always
evaluating the laser/tissue interaction to obtain the optimal result. Many new laser users make
the common error of using a fast and constant painting motion and moving the beam too quickly;
this improper technique will not allow proper ablation to occur. Electrosurgery, or
electrocautery, is not absorption-specific within a target tissue; as a result, extremely high
temperatures are created within the tissue mass to produce a desired clinical effect known as
fulguration. Electrosurgical techniques used at present for tissue ablation are unable to
control the depth of necrosis in the tissue being treated. Most electrosurgical devices rely on
the creation of an electric arc (between the treating electrode and the tissue that is being cut
or ablated) to cause the desired localized heating. These high temperatures cause a depth of
necrosis of more than 500 μm (often more than 800 μm and sometimes as high as 1,700
μm); the inability to control such depth of necrosis is a significant disadvantage to using
electrosurgical techniques for tissue ablation.8 Lasers do not suffer from electrical shorting
in conductive environments and certain types of lasers allow for very controlled cutting with
limited depth of necrosis, due to their inherent ability to absorb chromophores within a
specific target tissue.For the purpose of this article, clinical applications for lasers in
dentistry are separated into three different groups: soft tissue treatment, hard tissue
treatment, and non-surgical treatment.
Soft tissue lasers
Overall, dental lasers are relatively easy to use, as long as the clinician has been trained
properly. It is important to understand that lasers function with an “end cutting”
action (that is, laser energy is emitted from the end of the laser), while most other dental
instruments are “side cutting,” with the cutting edges or abrasive surfaces located
on the lateral surface. Although most laser soft tissue treatments heal by secondary intention,
the postoperative course usually is uneventful.9 Most laser excisional or incisional procedures
are accomplished at 100°C, where vaporization of intra- and extracellular water causes
ablation or removes biological tissue. Clinicians must be wary of the heat generated within
tissues during a procedure. If the tissue temperature exceeds 200°C during a lasing
procedure, carbonization and irreversible tissue necrosis will occur.6 This adverse consequence
can be avoided completely by using the lowest power setting necessary to achieve the desired
treatment goal. There are specific soft tissue indications for the clinical use of lasers,
including anterior gingival esthetic recontouring, gingivectomy/gingivoplasty (for crown
lengthening procedures), operculectomy, removal of epuli, incisions when laying a flap, incision
and drainage procedures, frenectomy, vestibuloplasty, coagulation of extraction sites, treatment
of herpetic and recurrent aphthous ulcer lesions, uncovering of an implant, pre-impression
sulcular retraction, and ablation of an intraosseous dental pathology (such as a granuloma or an
abscess). Other excisional laser procedures involve the removal of soft tissue targets that may
appear as benign lesions (such as fibromas or papillomas) on the lip, tongue, buccal mucosa, or
palatal area; the removal of coronal pulp as an adjunct to root canal therapy; excisional
biopsy; and sulcular debridement.
Diode (810 nm, 940 nm, 980 nm, 1,064 nm)(Pioon laser systems provide), Nd:YAG (1,064 nm), CO2
(10,600 nm), Er:YAG (2,940 nm), Er,Cr:YSGG (2,780 nm), and potassium-titanyl-phosphate (KTP)
(532 nm) lasers are the wavelengths used most commonly for soft tissue procedures.2 Diode and
Nd:YAG lasers are alike in that these lasers are absorbed in pigmented tissues (melanin and Hb)
and both wavelengths are transmitted to their targets in contact with a thin flexible quartz
fiber. CO2 laser energy is absorbed in the target tissue’s water content and transmitted
to the intended target using a hollow waveguide or an articulated arm. Erbium laser energy is
transmitted to the intended target tissue by a clear sapphire or quartz tip, either in contact
or approximately 0.5 mm from the target.2 Each wavelength has its own unique interactive
qualities and a different clinical feel that operators must experience to attain a certain
comfort level. A soft tissue crown lengthening procedure can be accomplished by using any of the
laser wavelengths mentioned above.