LASERS AND ORAL TISSUES : IN A NUT SHELL

                            LASERS AND ORAL TISSUES : IN A NUT SHELL

The past decade has seen various innovative researches that made an impact or revolutionized the standard of dental care. 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 growing awareness 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.

 All the Successful dentists have a true passion for their profession. Staying current on the means and methods to practice, properly evaluating technology and embracing changes to improve their practice, will nourish that passion. However, with the recent advances and developments of wide range of laser wavelengths and different delivery systems, researchers suggest that lasers could be applied for the dental treatments including periodontal, restorative and surgical treatments.

 

LASER – (LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION).

A devise that emits an intense coherent directional beam of radiant energy by stimulated electronic or molecular transitions to lower energy level.

DISCOVERY OF LASER:

Einstein’s atomic theories on controlled radiation can be credited as the foundation for lasers technology in 1917.Nearly 40 yearly, American physicist Townes first amplified microwave frequencies by the stimulated emission process and the acronym MASER – microwave amplification by stimulated emission of radiation came into use.

In 1958, Schawlow AND Townes extended the maser principle to the optical portion of electromagnetic field, hence the name laser. In 1960, the first working laser, a pulsed ruby instrument, was built by Maiman of Hughes research laboratories, of 0.694mm and in 1961 second laser neodymium laser by SNITZER.

Goldman in 1962 established the first laser in medical laboratory at university of Cincinnati, as he is recognized as the first physician to use laser technology initially working with the ruby laser.L’esperence was the first to use argon laser in 1988 in ophthalmology.In 1972, string and jako, carbondioxide laser in otolaryngology.Keifhabes et al in 1977 first to use neodymium, yitrium – aluminum- garnet.

LASERS TYPES USED IN DENTISTRY

Historically, the first lasers to be marketed for intraoral use generally were corbondioxide lasers with otolaryngology clearances authorized by the FDA.During 1970s and 1980s, intraoral use of co2 lasers was confined to specialists, such as surgeons, oral surgeons and some periodontitis. It was not until 1990 that the field of laser dentistry began in earnest in USA, atleast in clinical terms. In may 1990,the FDA cleared for intra oral soft tissue surgery a pulsed nd: laser developed by Myer’s and Myer’s, recognized as the first laser designed specifically for general dentistry.

                                    USES OF LASERS IN PERIODONTICS

Lasers used for periodontal therapy

Laser type                                           wave length

Argon                                                    488-515

Co2                                                          10,600

Nd:yag                                                  1064

Diode                                                    800-980

Er:yag                                                         294

Xeci exemer                                           308

 

USED IN:

–          Soft tissue recontouring

–          Sulcular debridement

–          Hemastasis

–           Soft tissue ablation, removal of large masses of tissue

–           Bactericidal effects in pockets

–           Curettage

–          Deepitheliazation

–          Fine soft tissue ablation

–          Incision

–          Soft tissue anesthesia

–          Root desensitization

–          Second stage implant surgery

–          Osseous surgery

–          Excision biopsies

–          Soft tissue welding

–          Frenectomy

–          Apthous ulcer treatment.

ARGON LASER;

       It is one of the first lasers to be used in treatment of vascular lesions. It was invented in 1964 and was used initially to treat retinal detachment. Treatment of skin lesions gained popularity  during the 1970’s .

              The laser is delivered through a fiber optic cable to a hand piece. The spot size normally used is 0.1cms and the beam is defocused, prior to treatment, LA must be used, generally avoiding vasoconstrictors to allow the dilation of the target vessels. When commencing treatment, the lesion is stabilized by an assistant and the affected area is slowly but continuously ablated using either a to and fro painting motion or a circular technique, starting in the center of lesion and working gradually outward.  Superficial vessels may be simply traced.

             The end point for the treatment of mucosal or submucosal lesions is collapse of the lesion with whitening of the surface mucosa. Deep venous cakes of the lip may more effectively treated by the glass slide technique .In this technique the clear glass slide is pressed on to the venous lake in order to flatten lesion and bring its deeper aspects closer to the surface.

CARBONDIOXIDE LASER :

It was developed in 1964 by patel and operated by bell laboratories.

            With the co2 laser, the rapid rise in intracellular tempatature and pressure leads to cellular rupture as well as release of vapour and cellular debris termed laser plumes. The debris arising from the site of impact, the char is carbonized tissue by the laser beam. Char formation occurs more rapidly during the continuous wave mode than wiyh pulsed or gated modes. If the char is allowed to accumulate irradiation is attempted through it. There will be a rapid jump in temperature to 1500­o  to 2000o c and the irradiated site will begin to condense to organ glow, causing extensive thermal damage Therefore proper use of the laser requires removal of the accumulated char layer during surgery to reestablish a moist surgery for absorption of laser energy.

            The co2 laser wavelength is readily absorbed by water .As soft tissue is 75% to 90% water, about 98% of the energy is converted to heat and absorbed at tissue surface with very little scatter or penetration. Thus only narrow zone of coagulation necrosis may surround the vaporization of co2 laser incision.  Because with this co2 laser , no contact is made with the tissue ,no tactile feedback occurs, but the tissue ablation can be precise with careful technique.

The depth of laser incision is proportion to the power setting and the duration of exposure.co2 laser surgery of oral soft tissues is generally performed with a power setting of 5-15 watts, in either a pulsed or continuous mode. The higher energy levels are required to vapourize and remove tissue, while the lower energy levels are used for homeostasis and photocoagulation.

ADVANTAGES:

Production of sterile surgical field, bacteriocidal, vermicidal.
Minimal cicatrix formation and wound contraction.
Access to difficult to reach anatomic sites by reflection or through waveguides.
Ability to coagulate, vaporize or incise tissue.
Good homeostasis.
Reduced local tissue trauma and oedema.
Precise delivery of energy to diseased tissue.
Reduced pain by induced neural anesthesia as a function of neuron sealing and decreased pain mediator release.
Minimized tumor cell dispersion by lymphatic sealing.
Little chance for mechanical trauma.
Little or no need for sutures.
Decreased scarring.

 

 

DISADVANTAGES:

Specialized didactic and clinically oriented instruction required for laser use by the surgeon and ancillary assistants.
Hazards to patient ,operating and assistant team of anesthesia personal from misdirected and inadervant laser radiation
Exposure of laser equipments.
Specialized wiring and plumbing connections.
Maintenance requirements.
Fire hazard as related to anesthesia risk.
Electrical hazard of laser equipment.

Nd :YAG laser :

            In 1989 ,myer’s et al published the first article on the pulsed Nd : YAG laser in periodontal surgery. The 0.064nm Nd:YAG laser can be usedin contact and non contact nodes for cutting and ablating tissues. A distinct advantage of this laser is that the fibrooptic tip ,when cleaned or prepared properly accumulates a coating of carbonized tissues at the tip.This tip highly absorbs the laser energy and maximizes the transfer of light energy into thermal energy ,which minimizes the tissue penetration .When used in a contact mode ,the pulsed Nd:YAG laser does not penetrate the tissues to any degree greater than the co2 laser.

            The depth of penetration is estimated to be 2+\- 1mm in soft tissues.A recent study concluded that thermal damage may occur to the condensing bone when YG:NAG laser is used at appropriate energy levels during soft tissue ablation.A significant increase in the intrapulpul thermal damage has also been reported when the devise was used to remove the smear layer from roots in the vitro.It is highly absorbed by pigmented tissues and is about 10000 times more absorbed water than an argon laser. The free running pulse mode allows the clinician to treat thin or fragile tissue with a reduction in heat build up in surrounding area.

            It has a long cooling time, commonly used for cutting and coagulation of dental tissues, but there is little interaction with sound tooth structure , allowing tissue surgery adjacent to the tooth to be safe and precise.

            The fiber usually is bare ended, In contact with tissue. During use the fiber end needs to be cleaved and cleaned otherwise the laser light rapidly looses its effectiveness. When used in contact, defocused mode, this wavelength can penetrate several mm into soft tissue, which can be used advantageously for delivering the laser energy to the inner surface, for e.g. ulcerated lesion.

DIODE LASER

            The diode laser is a relatively new addition to the periodontal armentarium. When used in the contact mode, the continuous wave diode laser at low power is a useful instrument for excising tissues and for reducing bacteria in periodontal pockets. Wavelength used is 819 nm. The power out put for dental use is generally around 2 to 10 watts can be either pulsed or continuous mode. The diode laser has been shown to have similar tissue effects as the ND: YAG laser in comparable studies with less thermal effects with the deeper tissues.

ERBIUM – YAG LASER

            Has a active medium of a solid crystal of yetrium – scandium – gathium – garnet that is doped with yetrium and chromium.Boundary of near infrared and mid infrared invisible and nonionising portion of the spectrum.

            The primary emphasis of utilizing lasers only on soft tissue was changed in 1997 with FDA safety clearance for the use of ertrium.It has got a wavelength of 2940 nm which is ideal for absorption by hydroxyapatite and water making it more efficient in ablating enamel and dentin than any previously introduced laser. This wavelength corresponds to the absorbtion coefficient of water ,causing water to evoparate into steam in the tissues being irradiated and resulting in a micro explosion of hard tissue.This process of ablation allows very little heat generation into underlying tissues and minimal elevation of the pulpal temperature.It absorbs 15000 times more water than ND:YAG laser.The tissue destruction caused by Er:YAG laser & probably not related to thermal effects or with other types of lasers,but to the microexplosions associated with the water evaporates with in the cementum andother dental hard tissues.

            The Er:YAG laser utilizes a fiber optic delivery system with an accompanying helium – neon laser as an aiming beam, since the wavelength is invisible.It is essential  to use a spray to wet the surface during laser radiation to achieve maximum efficiency of tissue removal with minimum heat generation. The surface is left with an acid – etched appearance microscopically which enhances the bond strength when used on enamel for cavity preparation.

PULSED- DYE LASER

THE continuous or pulsed – laser has become an excellent modality for the treatment of superficial vascular lesions because of its excellent selective absorbtion by the HB with little or no effect on surrounding tissues.The dye laser ,especially pulsed dye has found usefulness in the treatment of children in whom postoperative scarring is minimal.

EXCIMER LASER

            No pathologic changes in the tissue layers adjacent to the directed areas were found after the ablation of dental tissue with 193 nm.This laser by Frentfen et el in 1989.

APPLICATION OF LASER IN PERIODONTICS :

            Laser technology has an adjunctive role in the field of periodontal surgery.

1) Gingival hyperplasia: The co2 lasers (10600nm) are the definite choice for gingivectomy procedure because of its speed .The laser has demonstrated practical applications in patients who exhibit gingival hyperplasia associated with a systemic haemorrhagic disorder and classic periodontitis concurrent with similar coagulopathies. The hyperplasia was removed with the co2 laser with blood loss of less than 200 ml,despite a platelet count that was never more than 15000.Even ND:YAG is also used here(1064nm)both with infrared range; they must be combined with other types of visible lasers for the beam to be seen and aimed. But the healing is delayed when compared with healing of the conventional scalpel gingivectomy. Indicated power setting ranged from 4 – 10 watts depending upon the thickness of the tissue and the beam is used in both focused and defocused mode. To precisely counter the gingival margin, the beam is used away from the gingival margin in focused or defocused mode to simply ablate or vaporize the excessive tissue. (Ab et al 1998).Even the diode laser is used for gingivectomy.

2) Gingivoplasty: co2 lasers are the choice for this procedure. There are extremely past procedures, the laser is used in focused or in defocused mode with indicating power settings from 2-5 watts depending upon the size of the lesion.

Even ND: YAG laser has the capacity to operate at high penetration rates. A gingivectomy and gingivoplasty was performed on very delicate sulcular epithelium and by changing the pulse rate and power setting a frenectomy was performed on fiber tissue. The recontouring and removal of gingival tissue can be easily accomplished with the argon laser. The laser can be used as the primary surgical instrument to remove excessive gingival tissue and with it will provide hemostasis and weed the wound under LA. Like deepithelialization and retraction procedures here is a variety of technique to accomplish the desired tissue removal.

While all of the variations are effective, the clinician must develop a technique ,he or she is comfortable with a recommended technique to use 300 µm fibers in contact at 1.0 to 1.8 w continuous wave with a water spray.This will create power densities of 1400 – 2600 w\cm2 at the fiber tip and tissue temperature of 100 – 150o C. The power will need to be adjusted in this range based on the pigmented and fibrous characteristics of patients tissue. The goal is to accomplish effective tissue removal with minimal tissue damage to the surrounding tissues. The fiber is placed against the tissue and in a sweeping motion the tissue is either coagulated or is incised.

3) Frenectomy: There is no better use for co2 laser than for maxillary midline or lingual frenectomies .In maxillary frenectomy, the frenum is simply vapourized with the co2 laser. In lingual, the tip of the tongue is grasped, the tensionis placed and from the greatest concavity of the frenum moving posterior. Indicated power settings usually to 4- 5 watts in the slightly defocused mode (pick 1993).

            Argon laser is valuable tool in performing frenectomy procedures .The argon laser was largely effective in cutting fibrous tissue at higher energies. It is also beneficial for lingual frenectomy because of the haemostatic property .Laser contact scalpel is the instrument of choice with laser set at 1.0 to 2.25 W continuous wave delivery. The laser scalpel is placed on the frenular tissue which is excised. Water spray may be used. The tissue is removed with conventional standard incision design. Care should be taken not to damage the wartons duct. The frenum can literally be cut away, excellent homeostasis occurs.

4) CROWN LENGTHENING PROCEDURES

            lasers can be used very effectively for this purpose.Power setting ranging from 3-6 W is indicated with beam moving from a focusing mode to defocused mode as necessary.To protect the underlying tooh,no7 wax spatula is kept in the sulcus.

5) HYPERSENSITIVITY

            Lasers have proven to be very effective in reducing or completely eliminating the temperature sensitivity, especially that due to cold. The exact mechanism is still not known.

            It is said that in some ways ,they effectively seal the dentinal tubules.or co2 lasers, the beam is used in defocused mode and indicated low power setting 1-2 W .Some operators places a fluoride gel over the root surface first before lasing the tooth. The reported result which comes from numerous operators and institutions are impressive, possible mechanism include the narrowing or occlusion of dentinal tubules and nerve analgesia through depression of nerve transmission. Nd:YAG,GA-AR AND CO2 lasers are used.

6) REMOVAL OF GRANULATION TISSUE

            The co2 wave length is also used to remove the granulation tissue either to periodontal clean out or for degranulation of wound site present in certain furcation areas ,circumferential defects,intra bony defects and three wall defects,where stubborn tissue tags can persists. The laser can help either entirely to degranulation or partially degranulate these areas.CO2 lasers with hollow wave guides are recommended for this purpose .Since the tip can be easily directed to the site to be degranulated.The laser is used in focused or near focused mode and power setting adjusted from 1-2 W.

7) EXPOSURE OF IMPLANTS:

            co2 lasers work exceptionally well for uncovering implants – whether they be single or multiple fixtures. For this indication, the co2 lasers simply vaporizes the overlying tissues until the surgical healing cap is reached .This is accomplished with a defocused mode ,a circular motion and an indicated power setting of 3-6W.This can also be referred to as a “cookie cutter” approach. The opening can then be easily contoured and enlongated as needed.

When applicable, the laser eliminates the need for a flap and suturing and reduces the level of past operative discomfort that would normally be associated with this procedure .However conventional flap procedures may be performed in cases of which there is a need for apically positioning a flap or for uncovering implants within osseous structures. When regeneration material such as gore-tex, augmentation fiters, need to be recovered, the lasers is not recommended.

8) ANALGESIA

            laser induced analgesia is a phenomenon the rational of which is not well understood.Researchers have theorized that certain wavelengths of laser energy interfere with sodium pump mechanism,change cell membrane permeability,alter temporarily the endings of the sensory neurons and block the depolarization of c and a fibers of the nerves.Inthis area,the pulsed Nd:YAG laser has commanded most attention.

9) COAGULATION CAPACITY

            The co2 laser is commonly used .This because of its excellent coagulation ability,flexible fibro optic delivery system,ease of use and precission.Even HO:YAG lasers also used.Diode lasers are also used rarely.Er:YAG laser is not often used of its limited coagulation abilities.

10) INSTRUMENT STERLIZATION:co2 lasers ,Nd:YAG and argon lasers could sterlize selected dental instruments.

11) HOLOGRAPHY:laser based holographic imaging application in dentistry have been investigated since the early 1970s.It can measure tooth mobility,tooth position.

12) BIOSTIMULATION:certain low level lasers may have biostimulation effects ranging from analgesia,pain relief,accelerated wound healing,fibroblat proliferation,bone formation,reduced gingival inflammation and oedema,reduced dentinal hypersensitivity and treatment of carpal tunnel syndrome.

13) LASERS IN IMPLANT DENTISTRY: before any laser surgery is attempted, the initial surgery and healing process should be evaluated. Arigidity fixated implant with no crestal bone loss and adequate zones of attached gingiva should be present. Soft tissue thickness of 1-3mm and no tenderness or discomfort under vertical or lateral forces is needed.

Once the implant is uncovered with the laser under minimal anesthesia, the rigidity can be verified and most important any discomfort with lateral or vertical forces can be expressed verbally because only the soft tissue overlying the implant is anesthesized .Soft tissue greater than 3 mm thick should be reduced with the laser to create an ideal pocket depth around the implant.If the bone defecs are encountered or the width of attached tissue is less than 3mm,full surgical reflectionis recommended.

ROOT PREPARATION AND CONTROL OF SULCULAR MICROFLORA.

            Root preparation using the pulsed Nd:YAG laser alone or in combination with manual curettage,was studied by cobb.This study involved topographic examination of root surfaces in a scanning microscopy and DNA probe sampling to access the effects of laser application in advanced periodontal pockets of microbial population as well.At energy levels of 3.0 W at 20pps,2.25W at 20pps with change in time of applicationfrom 1-3mnts with pre and post lasing manual curettage,The authers found changes in the topography of root surfaces with significant residium of plaque and calculus deposits in all specimen.            Moreover ,although there was a significant reduction of populations of putative microorganisms mainly consisting of A.actinomycetocomitans,Porphynomonas gingivalis,in the period immediately after lasing,then was a gradual repopulation of these species.Laser pocket thermolysis has taken to used to describe the control of pathogenic pocket flora by argon laser energy,in conjunction withscaling and rootplaning.The laser tips inserted into the pocket,extending to the base and moved around the tooth, circumferentially .The pathogens are carbonized as are the adherent plaque deposits and some of the adherent plaque deposit on the root surfaces as well. Root instrumentation follows to remove the material from the pocket which leaves a smooth root surfaces which is compatible with healing of the soft tissue inflammatory lesion.

ROOT PLANING AND CURETTAGE

Epstein in 1992 described the Nd:yag laser for curettage teeth as follows:

–          Use a 320 µm fiber , 1.5 – 2.0W,15-20pps.

–          Insert to pocket depth and irradiate,keeping fiber parallel to root.

–          Move fiber horizontally and vertically.

–          Stop when there is fresh blood.

–          LA is usually not needed.

            Gold and viraldi in 1994,attempted to look at the histology immediately after ND:YAGlaser curettage.he has described sharp margins with intact nuclei and conclude that the contact tip laser can remove sulcular epithelium without collateral damage.Their histology shows remarkable degree of cellular disruption in one figure extending through out most of the height and thickness of the tissue .This cellular tear drop shaped disruption is conceivably the result of deeply scattered and absorbed ND:YAG laser light . if it were solely from the surface heat one would expect a more radial nature to the distribution of the disruption.

            In 1995 henry and colleagues reported that the argon laser was able to selectively kill bacteria, with pigmented species being more sensitive.Mayer’s noted that indicated candidates for laser curettage are patients with periodontal pockets of 3 – 7mm.Application of laser energy for curettage is photo coagulation or vaporization of soft or fibrous tissue within the periodontal pocket subjacent to alveolar crest.           During this procedure the coagulated epithelium will be cleanly evident and need to be wiped out from the fiber tip with a sterile gauge.

POCKETS

            To deal with a vertical pocket  associated with a severe bone loss ,most surgeon using a laser would combine it with a traditional instrumentation.Usually the defect is debrided with conventional flap surgery,followed by laser de-epithilialization weekly for several weeks.After flap surgery defect is debrided and root planning is performed.The wound is next treated with a pulsed ND:YAG laser for closure of healing.The root surfaces and alveolar bone are treated with the laser set at 1.8W and 15 pulses per sec .The specific use of the laser is to provide for other properties recognized as advantages of laser energy. After initial debridement  and raising periodontal defect is de-epithilialized weekly for 10 weeks.The quantz fiber of the laser is placed apical to the periodontal ligament attachmentof the epithelium and gingival connective tissue is removed coronally.after lasing the defect is debrided and root planning is performed.

COMPLICATIONS

Classification by ossoff et al 1983; Meyer’s 1981.

A modification by fried 1986 is used as it focuses on mechanism of injury and can be applied to any anatomic site.

1) Direct laser effect:

a)      Burning to mucous membrane: while giving incision or while giving during any surgical procedure ignition can be caused. This is the frequent complication arising from direct laser effect, it can cause burns to mucous membrane, teeth. The burns are usually localized and minor, but may be more or less serious if continued laser bursts are applied prior to recognizing the problem. The recognizing of tooth injury may be delayed for several weeks often the injury. The usual cause is an improperly aligned laser beam. The injury can occur to the patient or to the operator.

b)      Corneal injury: since the cornea is 75% water, the absorptive index of the cornea is close to that of water.co2 laser radiation is selectively absorbed by cornea, mostly in the superficial layers. Corneal injury may occur either to the patient or to the operator and may result from a direct or reflected laser beam. Glass and plastic also absorb co2 laser radiation and act as effective protection.

c)      Ignition of cotton pledget or other flammable packing drapes: the kindling point of paper and fabric product is very low. If a laser beam strikes one of these products in a dry state, ignition is almost instantaneous.

d)      Burns to the operator: this injury is fairly frequent, usually occurring as burns to finger placed in the laser beam.

e)      Haemorrhage: the co2 laser will provide only limited haemostasis and is usually effective for only smaller vessels.

2) Indirect laser effect:

a)      Effects caused by laser beam striking a reflective surface: any of the complications listed above can be caused by the reflectoion of laser beam.

b)      Airway obstruction by charred tissue: even when an endotracheal tube is not used, excessive mucosal charring can build up and obstruct the airway.This charred tissue will also allow heat to build up since the charred tissue contains little moisture and don’t vaporize.

c)      Burns to mucosa and skin caused by heating instruments by laser .

3) Complication caused by equipment effects:

    Injury caused by improper wrapping of endotracheal tube. Improper wrapping of   

    endotracheal tubes with reflective tape can produce sharp edges. These will 

    cause injury to the mucosa, particularly on intubation and extubation. This tape  

    can also loosen, causing airway obstruction.

4) Complication caused by delayed effects:

  oedema: while oedema may occur during the operative procedure,it is more likely to occur in the post operative period. If the oedema is extensive and involves the airway obstruction can ensue. Less severe oedema, particularly in the posterior glottis or pharynx may produce dysphagia and aspirations. Oedema may also be caused by vigorous instrumentations.

5) Thermal injury: any laser produces heat in the tangent tissues with an ideal of instantaneous vaporization without effect on the contiguous tissues. Some of the heat is dissipated as steam in the plume and the remainder is absorbed by surrounding tissues. Ideally again the tissues immediately adjacent to the site of laser energy must both absorb the heat without an undue inflammatory response and conduct the heat away from the site of radiation and by vascular system.

6) Overlasing the surgical target: delivering laser energy to the too high a level for the planned reaction of tissues in the tangent area will produce a burn. Achar is produced during lasing that must be wiped away to prevent it being released.If a char is exposed to continuing laser enegy, temperatures measuring in the range of 4000oC are generated ,which will conduct normal tissues.

7) Reflected laser energy: Sliney wrote “the principal hazard to personnel in the vicinity of an operating laser results from specialized reflections. highly polished metallic surfaces and convex surfaces on instrument  and equipment have no place in a laser beams from the polished surfaces and concentration of beams by convex curvatures produce uncontrolled and damaging laser energy.

8) The surgical team: Carlson “if the surgeon and staff members interrupt the laser beam path, they suffer burns as result .these accidental encounters with the lasers are common place, especially when the surgeon is working with a new inexperienced assistant.

9) Explosive potential : materials with an explosive potential when exposed to an igniting heat, such as inhaling anesthetic agent  and topical anesthetic skin freeze spray preparation ,absolutely  should not be used in conjunction with laser surgery.

10) Surgical site: surgery is surgery no matter how elegantly done and what cutting instruments used. With laser there is possibility of augmentation of tissue responses and post operative pain, comparable that associated with surgery with a scalpel, especially if application of laser energy is not exact.

 

11) Hypertropic cutaneous fibrosis: following laser surgery through cutaneous tissues, hypeertrophic scaring is most frequent undesirable dermatologic side effect. The thermal energy of laser alters the contiguous tissues and sets stage for hypertropic scarring. The greater the depth of the necrosis of lasers greater alterations in the contiguous tissues.

12) Post operative discomfort: pain in related to thermal aspects of lasers on the contiguous tissues .The greater the penetration of laser energy, the greater the inflammatory response and more intense the hypoesthesia. Penetration of superficial fascia may permit herniation of adipose tissue., increased pain due to neurotic damage.

13) Infection: it is possible that the decreased vitality of the contiguous tissues,owing to the thermal damage, may provide a regional site for opportunistic microorganism to flourish if there as been contamination.

UNFOUNDED CONCERNS :

The area of the new technology may produce unfounded apprehensions and claims of complication in relation to laser surgery. There is no scientific basis for believing lasers could be a hazard to a foetus. The mis understanding probably is an outgrowth of confusion between laser radiation and ionizing radiation.

PRECAUTION AND MANAGEMENT OF LASER:

The laser safety is an issue limited not only to the performances of treatment with dental operators but one that also encomposes the interrelationship among the health care providers,educational institutes ,government (miserdino 1992).

1) Personnel Protective equipment : while using lasers one must wear adequate eye protection,including the patient.This can be provided by either safety goggles or screening devises, however the means selected must be designed specifically for use with the particular wavelength of laser radiation.

While selecting appropriate protective eye wear following should be considered:

a)      Wavelength of laser emission

b)      Maximum permissible exposure limits.

c)      Degradation of absorbing media or filter.

d)      Optical density of eye wear

e)      Radiant exposure limits.

f)        Need for corrective lenses.

g)      Multiple wavelength requirements

h)      Restriction of peripheral vision

i)        Comfort and fit.

2) Control of airborn contaminants : the laser plume,which is the smoke or vapor emitted from the site of surgery during exposure to laser energy is special concernThe plumeshould be regarded as potentially hazardous both in terms of  particulate matter and infectivity.Although it is highly unlikely that viable tumor cells occurs in laser plume.it has been reported that intact viral DNA can be liberated into the the air with the.vapor created during co2 laser treatment of the verraccae.it also has harmful effects on respiratory system.

            Airborn contaminants can be controlled by ventilation,evacuation or other methods of respiratory protection.airborn contaminants should be removed as near as possible from the point or origin by evacuation and ventilation to the outside if possible or by recirculationg air filtration systems.adequate suction in the cut surgical field must be maintained at all timesespecially when trating pathologic conditions that are suspected of being viral in origin to limit the possibility of spreading that virus via the laser plume.accordingly,the evacuation system should be able to remove particle as small as 0.3µm with atleast an 80% efficiency.surgical staff should wear mask to remove the particles .Eye wear ,face shield and cps or growns should be worn to protect the personnel from splatter and laser light.

3) Beam alignment : the beam alignment should be checked before any surgical procedure by using a moistened tongue depressor and firing the laser to prevent combustion.

4) Reflected energy : polished instruments should not be used because of the potential for reflected lasers energy to cause damage only anodiozed ones should be used.

5) Fire protection : the use of fire is always concern when laser is used .when using laser non combustable materials should be used.All combustable materials must e kept in closed cabinets and any combustion fluids that is used in surgical preparation must be dried before surgery.

 

6) Anesthesia: when laser is used for nasotrachial surgery,moist pack must be used to protect the tube from accident al laser damage.because any exposure of anesthetic agent to the laser beam can cause combustion in biomaterial system .

7) Tissue damage : when laser is used for tissue incisions ,the power density and the time used by the laser should be rwespected.It can cause tissue damage and it can be prevented by preventing carbon arcing,the tissue should be regularly wiped clean of co2.

8) Tissue protection: the tissues of oral cavity should always be protected from over exposure of laser energy though by unintension, which may lead to bone necrosis.

CONCLUSION:

The space age has arrived. No longer are lasers something that are only used in movies or opening ceremonies of mega events.incresingly ,lasers are finding a niche in many aspects of life and this includes dentistry. In addition, its bactericidal effect with elimination of lipopolysaccharide, ability to remove bacterial plaque and calculus, irradiation effect limited to an ultra-thin layer of tissue, faster bone and softtissue repair, make it a promising tool for periodontal treatment including scaling and root surface debridement. 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.

 

1.Dr.Arati c koregol,Reader,Department of periodontics,pmnm dental college,Bagalkot.

2.Dr.raghavendra M

3.Dr.Nagaraj kalburgi

4.Dr.Bhaghyashree vanaki

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