By Robert A. Strauss, DDS, MD - PowerPoint Presentation

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ByRobert A. Strauss, DDS, MD Steven D. Fallon, DMDPresented ByHani S. Al-Moharib

Laser in Contemporary Maxillofacial Surgery

Dent

Clin

N Am 48 (2004) 861–888

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Outline

Introduction.

Types and

Wavelenghts

.

Principles of Laser Physics.

Advantages and disadvantages.

Techniques for use in OMS.

Slide3

Introduction

Lasers are becoming the standard of care for many oral and maxillofacial procedures.

They are being introduced as an efficient instrument for a variety of new applications.

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Introduction

Oral and maxillofacial surgery (OMS) has included the use of lasers since the mid-1960s.

Lasers are becoming increasingly popular due to the advent of office-based lasers, which are:

Small.

Portable.

Easy to manipulate within the oral cavity.

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Types and Wavelenghts

There are many different laser wavelengths that have been used in OMS, Such as:

CO

2

laser.

Nd:YAG

laser.

Er:YAG

laser.

Ho:YAG

laser.

Argon laser.

Semiconductor diode lasers.

Nd

: Neodymium, Y: Yttrium, A: Aluminum, G: Garnet,

Er

: Erbium, Ho: Holmium

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CO2 Laser (10,600 nm)

CO

2

laser is one of the most widely employed lasers in OMS.

CO

2

laser is ideal for most soft tissue surgeries because it has excellent affinity for water-based soft tissues.

The absorbed energy causes:

Vaporization of the intracellular and extracellular fluid.

Blood vessels of approximately 500

µ

or less are sealed spontaneously.

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Nd:YAG Laser (1064 nm)

The

Nd:YAG

laser’s active medium is a crystal of yttrium, aluminum, and garnet doped with neodymium ions.

Nd:YAG

laser exhibits:

Minimal surface tissue absorption.

Maximal penetration

This allows for coagulation of tissue in depth so that vessels 2 to 3mm in diameter can be ablated.

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Nd:YAG

Because the pulse duration is shorter than the time required to initiate a nerve action potential,

Romanos

et al., believed that most procedures could be performed without local anesthesia and minimal bleeding.

The

Nd:YAG

laser also is unique in that it can be used in a contact (excision) and a noncontact (coagulation) mode.

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Nd:YAG

These properties have led to its use in a variety of maxillofacial procedures, including :

Coagulation of

angiomatous

lesions.

Hemostasis

in bleeding disorders.

Arthroscopic surgery of the TMJ.

Resections in vascular tissues.

Palliation of advanced

neoplasms

.

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Er:YAG (2940 nm)

Er:YAG

laser is particularly attractive for use in dental implant surgery. Because:

Beam is reflected by polished metal

surfaces

.

No adverse effects on titanium surfaces.

Application of the

Er:YAG

laser in dental implant surgery has been advocated for:

Preparation of hard tissue.

Second-stage surgery.

Revision of soft tissue.

Treatment of

peri-implantitis

.

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Ho:YAG (2100 nm)

The

Ho:YAG

laser offers:

Minimal lateral heat transfer and less peripheral tissue damage.

Profound

hemostasis

.

Precise cutting and controlled depth of penetration compared with surgical shavers and scalpels.

Can be used easily through saline solution or lactated Ringer’s solution.

All of these characteristics make the

Ho:YAG

laser the perfect instrument for TMJ arthroscopic procedures, such as

diskoplasty

,

diskectomy

, and

synovectomy

.

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Argon Laser (514 nm)

Argon laser is indicated for treatment of dermatologic, labial, and oral lesions with a large vascular component.

Argon laser is absorbed by pigment-containing tissues, including hemoglobin in erythrocytes, melanin in

melanocytes

, and other dark pigments.

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Semiconductor Diode Lasers (805-980 nm)

The optical penetration is less than that of the

Nd:YAG

laser; this is potentially beneficial for the treatment of superficial and interstitial lesions.

Romanos

and

Nentwig

et al., found that the incision margin using the diode laser is more precise compared with other systems, including the CO

2

and

Nd:YAG

lasers.

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Principles of Laser Physics

Lasers are totally absorbed by water within the first 0.1 mm of the tissue surface, causing, at 100C:

Intracellular water to vaporize and expand.

Leading to cellular rupture.

Loss of 75% to 95% of the cell volume as steam.

At higher temperatures, the residual organic matrix also vaporizes, resulting in total tissue ablation.

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Principles of Laser Physics

Given enough time, heat begins to leak laterally by thermal conduction.

This leads

to useful

hemostasis

, 500 µm of thermal damage in skin uniformly results in scarring.

Control of lateral thermal damage is paramount to the use of lasers in OMS.

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Principles of Laser Physics

Three parameters controllable by the surgeon function to control the laser’s effect on tissues:

Power.

Time on target.

Effective spot size of the beam.

By adjusting these parameters, one can create a deep thin cut into tissue for incision or excision or a wide superficial surface vaporization for tissue ablation.

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Advantages

The

hemostatic

nature of the laser allows surgery to be performed more precisely and accurately because of increased visibility of the surgical site.

Decreased swelling allows for increased safety when performing surgery within the airway.

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Advantages

Tissue healing and scarring also are improved with the use of the laser due to a combination of:

1- Decreased lateral tissue damage.

2- Less traumatic surgery.

3- Precise control of the depth of tissue damage.

4- Fewer

myofibroblasts

in laser wounds compared with scalpel wounds.

Decreased postoperative pain often can be obtained with the use of lasers for surgery.

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Disadvantages

Lasers does not yet compare favorably with conventional techniques for osseous surgery (

eg

, extraction of impacted teeth and

osteotomies

).

Speed of healing usually is prolonged compared with other types of wounds due to:

1- Sealing of blood vessels and

lymphatics

.

2- The need for

neovascularization

for healing.

- Typical intraoral healing takes 2 to 3 weeks for wounds that normally would take 7 to 10 days.

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Techniques for use in OMS

There are basically three

photothermal

techniques for laser use on soft tissues within the oral cavity and on the face:

Incisional

procedures.

Vaporization procedures.

Hemostasis

.

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Incisional and excisional procedures using the CO2 laser

This technique allows the surgeon to perform almost any intraoral procedure that normally would be done with a scalpel, such as

incisional

or

excisional

biopsy, lesion removal, or incision for flap access.

this technique would require a fairly high-power density using a small spot size to create a deep but thin cut, as would be needed to make an incision.

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Typical lesions treated by excision and incision include the following:Fibroma.Mucocele.Papilloma.Gingival lesions.Benign salivary gland lesions.Salivary stones.Malignancy removal.Incisional biopsy.Excisional biopsy.Vestibuloplasty.Epulis fissurata.Hyperplastic tissue excision.Implant uncovering.Peri-implantitis.Tongue lesions.

Incisional

and

excisional

procedures using the CO

2

laser

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basic technique for laser excision demonstrated in the removal of a

mucocele

.

(A) Outlining specimen in a repeating pulse fashion.

(B) Connecting outlined dots to create a vertical cut around lesion.

(C) Undermining and removing the specimen.

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Excision of T1N0M0 carcinoma of lateral tongue. (A) Outline of lesion. (B) Undermining and excision of lesion. (C) Resultant defect with large margins left

unsutured

. (D) Two-year postoperative view displays excellent healing with minimal scarring and functional deficit.

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Excision of tissue for second-stage implant surgery.

(A) Note lateral

angulation

of laser for exposure to avoid direct contact with implant fixture. An attempt should be made to minimize removal of attached tissue.

(B) Exposure of implant.

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Ablation and vaporization procedures

Tissue ablation (also called vaporization) is used when the surgeon wishes to remove only the surface of the target or to perform a superficial removal of tissue.

In these situations, the lesion usually is confined to the epithelium or to the epithelium and underlying superficial

submucosa

.

The

laser is defocused by pulling the laser back from the target and allowing the beam to widen to a spot size of 1.5 to 3 mm.

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Typical lesions treated by vaporization include the following:Leukoplakias.Dysplasia.Lichen planus.Papillary hyperplasia.Hyperkeratosis.Oral melanosis.Papillomatosis.Tissue hyperplasia.

Ablation and vaporization procedures

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Laser ablation of

leukoplakia

of

buccal

mucosa. (A) Diffuse

leukoplakia

of

buccal

mucosa. (B) Outline of lesion.

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(C) Ablation completed and char layer removed. (D) Resultant tissue defect left

unsutured

.

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Ablation and vaporization procedures

Many clinicians believe that the

hemostatic

effect of the laser results in decreased tendency for

hematogenous

or lymphatic seeding of the malignant cells.

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Premalignant lesion of

mandibular

gingiva

. (A) Preoperative photograph shows extensive growth, making

excisional

procedure difficult. (B) Defocused ablation of gingival lesion with remaining char layer.

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Cosmetic Laser Surgery

A common procedure performed is cosmetic skin resurfacing.

This procedure treats facial lesions and skin wrinkles by:

Removing the surface layer of the epidermis and superficial papillary dermis.

Contracting the dermal collagen.

Allowing the skin to

reepithelialize

in a more uniform manner.

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Ablation of pigmented facial nevus. (A) Pigmented facial nevus on left brow. (B) Resultant char layer after ablation of pigmented lesion. (C) Removal of char layer shows lack of remaining pigment.

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Laser-assisted uvulopalatoplasty

LAUP has become an attractive alternative to traditional scalpel

uvulopalatopharyngoplasty

(UPPP) for treatment of snoring and mild sleep-disordered breathing.

The procedure is designed to enlarge the posterior airspace and reduce or eliminate pharyngeal obstruction during sleep.

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Dental implants

Applications of the laser for implant surgery have focused primarily on:

Soft tissue revision.

Second-stage surgery.

Decontamination of implant surfaces.

Treatment of

peri-implantitis

.

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Dental implants

Properties of the laser offer significant advantages for soft tissue management surrounding dental implants, including:

Improved control of possible hemorrhage.

Less mechanical trauma to the soft and hard tissues.

Prevention of local infection.

Less postoperative inflammation and pain.

Improved healing.

Decreased risk of postoperative

bacteremia

.

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Dental implants

Concerns have been raised regarding the hazards of laser applications around implants. When using the laser, some of the energy may be absorbed or transferred to the implant, causing deleterious effects.

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Dental implants

Kreisler et al., assessed the effects on different implant surfaces of

Nd:YAG

,

Ho:YAG

,

Er:YAG

, and CO

2

lasers and concluded that the first two types should not be used for implant surgery because they harm the surface of all

endosseous

implants. The CO

2

and

Er:YAG

lasers can be used only at low power because they can affect the implant surface.

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Dental implants

Thermal damage also has been implicated in implant failures with adjunctive laser surgery.

Temperature increases of 47ºC to 50ºC have been shown to induce tissue damage in the bone leading to necrosis and failed

osseointegration

.

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Dental implants

In second-stage implant surgery, bone often is found above the healing cap or at the implant margins. Traditionally, this tissue has been removed using a combination of rotary or manual instruments.

In either case, extreme caution must be used to prevent damage to the implant surface. This situation has led to the advent of lasers for implant

uncoverings

.

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Dental implants

Peri

-implant infection results in inflammation of the surrounding soft tissues and can induce a breakdown of the implant-supporting bone.

The

CO

2

,

Er:YAG

, and diode lasers have been shown to be safe and effective for treating

peri-implantitis

.

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Temporomandibular joint surgery

Arthroscopic surgery has become the primary treatment of choice for surgical internal derangements of the TMJ. Lasers have several advantages compared with conventional cutting instrumentation and techniques, such as:

Diseased tissues can be removed without mechanical contact.

Decreased trauma to the

articular

cartilage and synovial surfaces.

Hemostasis

within the joint without causing thermal damage.

Technical precision of laser surgery is far superior.

Eliminates the possibility of instrument breakage and retrieval.

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Using this technique, such procedures as:Diskectomy.Diskoplasty.Synovectomy.Hemostasis.Posterior attachment contraction.Eminectomy.Debridement of fibrous ankylosis - All these can be performed on an outpatient basis through two incisions less than 2 mm each.

Temporomandibular

joint surgery

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Temporomandibular

joint arthroscopy using a

holmium:YAG

laser. Separate ports are required to provide the surgeon with visibility of the laser tip during use.

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Summary

The incorporation of lasers OMS has led to exciting advances in surgical therapy and improved patient care.

Advances in laser technology undoubtedly will yield new procedures and have a major role in the future of minimally invasive surgery.

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Thank You