Abstract
In oral soft tissue surgeries, and contrary to the conventional surgical techniques, laser treatments of blood or lymphatic tumors in the oral cavity and on the vermillion areas of the lips actually result in the best aesthetic healing without anatomical distortions of the healed sites. 1 –4 Further, because of the tissular biopotential of some laser wavelengths, the beam can be successfully used for the ablation of painful areas of the oral mucosa in lichen planus diseases. 5 The high potential of disinfection of laser beams can be helpful for the complete eradication of infected oral areas and for the treatment of viral tumors. 6 –10 Laser surgery induces a different process for oral soft tissue healing. The lased wounds produce a fibrin, 11 –15 which is highly beneficial in the case of operated gums. The healed gums become firm, enriched in fibrin, and more resistant to permanent oral traumas. The advantages of using the laser beam in oral surgeries are the reduction of inflammation and postoperative discomfort, appreciated quality of healed tissues, 16 –18 disinfection potential, and induction of fibrin production in lased tissues.
The use of some wavelengths of laser beams is also beneficial in the field of oral prosthetic surgery. The non-necessity of suturing the wound at the end of oral surgeries on healthy patients prevents having an anatomic distortion of operated sites and allows the preservation of vestibular length. The non-suturing of the wounds, on patients having removable dentures, after the ablation by laser beam of tumors or any gingival hyperplasia, allows the preservation and, in some cases, the increase of vestibular length, which is highly benefificial for the stability and the retention of dentures. 19,20 Laser beams can also be helpful in the case of oral aesthetic applications. The removal of gingival pigmentation (e.g., melanin or metallic tattoo) by laser beams can be performed in a bloodless surgical field, and it also reduces postoperative discomfort. 21 –27 The tissular production of fibrin offers a firm mucosa and an excellent aesthetic appearance for the healed site. Further, the use of laser beams is imperative for the removal of unaesthetic shapes of the lips 28 on aged patients (e.g., pseudotumor formation, loss in the symmetry of the vermillion area, scars). The aesthetic aspect of healed sites is caused by the absence of sutures and also by the ability of lased wounds to heal without scar formation. On the other hand, the use of soft lasers for low-level laser therapy (LLLT) offers a reduction in patient complaints because of an appreciated and significant reduction of inflammation in the postoperative period. Actually, the use of laser beam seems to be the best alternative for the treatment of mucositis, which is a common side effect of chemotherapy and radiotherapy in cancerous patients. LLLT reduces pain and allows tissue healing. 29 –36
The use of LLLT techniques is actually the only treatment allowing the complete healing of oral osteonecrosis and exposed bone in patients receiving bisphosphonate medication. 37,38
In conservative dentistry, laser beams offer many interesting applications. Dental cavity preparations by means of erbium lasers offer some advantages. The adaptation of the delivered energy density permits the selective ablation of the carious layer without the significant ablation of sound dental tissues, 39 –44 thereby qualifying as a minimally invasive technique. It has been proven that erbium lasers induce an increase in the caries' resistance to sound and lased dental hard tissues. 45,46 The use of laser beam for caries removal will allow the preservation of the natural shape of decayed cavities without the need for preventive extension of prepared cavities. Clean cavities can be easily filled with bonded filling materials. However, the heat generated during cavity preparations by means of erbium lasers alters the surface of the treated dentin. 47 The presence of this altered layer decreases the quality of dentinal bonding in the fillings. 48 Researchers are trying to improve the quality of bonding between lased dental hard structures and filling materials.
In operative dentistry, some laser wavelengths have the ability to produce a melting of dentinal surfaces by heat generation. This potentiality can be helpful in the treatment of dental hypersensitivity. 49 –51 The narrowing or complete closing of dentinal tubules by laser beams produces a significant immediate reduction of complaints, or total patient satisfaction. Further, LLLT can also induce a delayed important pulpal production of reactive dentin that can dramatically decrease the dental hypersensitivity. 52 –54
The use of the laser beam in endodontics seems promising. Several research groups are progressing in their studies with the aim of proposing some clinical applications in this field. A complete sterilization of root canals is not yet possible; however, some laser wavelengths can have an important disinfection effect and significantly reduce the presence of germs. On the other hand, erbium lasers can remove the dentinal smear layer by the cavitation effect; whereas other wavelengths can induce a reduction in apical inflammation. Some researchers are trying to use the laser beam to disintegrate the in-root broken metal tools or to remove the canal calcifications. 55 –59
In the dental bleaching field, some laser wavelengths can produce an immediate lightening of treated teeth by heating bleaching gel, thereby increasing the diffusion of bleaching agent in dental structure (photothermal effect). The KTP laser seems to have a double effect when coupled to a bleaching gel that is rich in rhodamine. The photothermal effect can be obtained by limiting the absorption of the light in the red-enhanced bleaching gel. The photochemical effect is obtained by the absorption of the beam by the tetracycline-stained teeth, 60 and also by the absorption of the laser light by the rhodamine molecule existing in the bleaching gel. This second effect provokes the transformation of the hydrogen peroxide into perhydroxyl ions in an alkaline pH. These bleaching agents are more efficient. 61 The teeth bleaching by means of laser offers the advantage of obtaining an immediate dental lightening instead of the delayed effect produced by home bleaching techniques.
In preventive dentistry, the use of a few laser wavelengths seems to allow immediate and permanent fluoride incorporation in dental hard structures. 62,63 It has been proven that the exposition of enamel to specific laser wavelengths, and under particular irradiation conditions and fluoride applications, can increase the resistance of lased enamel to caries attacks. 64 –68
We are convinced that the laser beam will become an important tool in the near future in all fields pertaining to dental practice. Many efforts are and should be made and extensive research is and should be conducted to fulfill this aim.