Low level lasers, cold or soft lasers:
These lasers do not produce thermal effects on tissues and induce photoreactions in cells through light stimulation which is called photobiostimulation. Power of these lasers is usually under 250mW.
The main point differentiating low level lasers and high power ones is the activation of photochemical reactions without heat formation. The most important factor to achieve this light characteristic in lasers is not their power, but their power density for each surfa ceunit (i.e cm2). Density lower than 670mW/cm2, can induce the stimulatory effects of low level lasers without thermal effects.
Low level lasers (therapeutic) used today as treatment adjunctive devices in medicine and dentistry. Numerous studies have been performed on the applications of low level lasers in patient pain reduction. Mechanisms of pain reduction with therapeutic lasers and their application are expressed, and the studies realized in this field are presented.
Some of the major benefits associated with Laser Dentistry are:
1. Laser assisted procedures performed on soft tissue may not require suturing through a process called tissue welding. This is a process that uses laser energy to anastomose tissues.
2. Minimizes bleeding by helping tissue coagulation.
3. Minimizes or even eliminates the need for anesthesia in certain clinical procedures.
4. Bacterial decontamination of deep periodontal pockets, root canal systems.
5. Removal of the smear layer after tooth preparations.
6. PDL regeneration? (LANAP protocol)
7. Stimulate healing of injured tissues.
8. Attenuate pain.
9. Enhance remodeling and repair of bone.
Applications of LLLT in dentistry
LLLT has been used effectively in dentistry for more than four decades, though the magnitude of the positive clinical effects has just started to be documented in double blind placebo controlled studies in the last ten years. Clinically, low-level laser therapy can be used as an adjunct to surgical laser procedures as well as a treatment adjunct to other dental treatments for numerous conditions and applications, some of which are noted below.
Some of the most frequently used clinical applications in dentistry include:
Laser irradiation will significantly decrease pain, swelling, bruising and inflammation after an extraction thus requiring a decreased (or eliminated) need for post-operative analgesics. The speed of healing of the extraction site will also be increased and there will be a reduced likelihood of a dry socket (although in cases where a dry socket does occur, LLLT will dramatically decrease the pain and stimulate the covering of the exposed bone through the stimulation of fibroblasts).
LLLT is being used by many dentists and pedodontists for analgesia of primary tooth restorations. Application at the apex decreases the conduction of nerve impulses from the pulp and stimulates the release of endorphins, both which contribute to a decreased pain sensation (analgesia).6 Though this technique works best on primary teeth (Figure 2), laser irradiation will allow for comfortable air abrasion treatments and crown & bridge cementations. Without the effect of anesthetic, it is easier to accomplish a proper bite adjustment.
Nausea and Gagging
Many patients have a sensitive gag reflex making dental work very stressful for both the patient and dentist. Application of the laser to the P6 acupuncture point of the wrist will decrease the gagging and nausea sensations many patients feel during dental treatments, impressions and x-rays.7 The P6 acupuncture point is one of a triad of points that calms your parasympathetic nervous system (Figure 3). Application of these points is also effective for patients who are anxious and nervous.
In any case of a dental infection, the laser can be applied to the submandibular lymph nodes to increase the lymphatic flow of the infected area, reduce the inflammatory cells and bring neutrophils to the site of infection for faster healing (Figure 4).8 Laser therapy will not preclude the use of antibiotics in most cases but will help to potentiate the uptake of the antibiotic into the blood stream.
Laser irradiation during the preparation and placement of implants will decrease the pain and inflammation of the surgical procedure and improve the integration of the implant into the bone. Many studies investigating the effect of LLLT during implant placement have demonstrated an improved bone formation around the implant with a substantial decrease in post-operative pain.9
In addition to reducing the pain felt during orthodontic treatments, laser irradiation has also been shown to increase the velocity of tooth movement. A recent study demonstrated that over 60 days, the canines on the laser treated side moved 34% more than the control.10 It has been postulated that the increased speed of tooth movement is a result of the stimulation of the osteoblast/osteoclast turnover.
Laser therapy can be used very effectively for facial pain treatment, either acute or chronic. A major complaint a lot of patients have after long dental appointments is facial pain and muscle tension.11 Application of the laser to the masseter muscle after the appointment will reduce or eliminate the muscle trismus and joint pain. In chronic TMJ cases, laser therapy can be used in conjunction with other therapeutic tools to reduce the pain and muscle tension, while stimulating healing within the joint.
LLLT can assist with pain and inflammation after endodontic procedures and surgery, treat pulp hyperemia, help diagnose irreversible pulpitis and reduce the need to post-operative analgesics.Further, laser irradiation is very effective in treating dentine hypersensitivity. A recent study demonstrated that combining laser therapy with a chemical agent produced an average success rate of more than 85%.12
Soft Tissue Lesions
Soft tissue lesions, such as herpes lesions, denture sores, angular chelitis and lichen planus, respond very well to LLLT. Research has indicated that LLLT can prevent cold sores from erupting if treated in the prodromal stage (when the tingling starts) and speed the healing in cases where the sore has erupted.
Clinically, light therapy can be used with ease in a dental office. Because laser therapy is non-invasive and has no significant side effects, the treatments can frequently be done by the auxiliary staff and easily integrated into the practice.
Light therapy uses the body’s own natural resources to provide pain relief, muscle relaxation, wound healing and nerve. Low Level Laser Therapy offers a dentist the opportunity to better manage treatments that are often deemed painful by patients while enhancing their practice with improved clinical treatments and patient satisfaction.
One of the most interesting and useful aspects of LLLT is the safety. Lasers only elicit responses from cells that can utilize the energy produced, thus will have no negative effect on healthy cells.13 In the hundreds of studies done on laser therapy, no clinical side effects have been reported. This puts lasers in the public domain and with very basic training, can be used by the whole dental staff.
A huge benefit of Low Level Laser Therapy is that patients see their dental practitioner doing something extra to reduce the pain or discomfort that may have been caused during the appointment. The very nature of what dentists do causes pain and inflammation. LLLT requires a paradigm shift; instead of using drugs to treat the pain after it has started, a dentist now has the opportunity to treat the pain immediately in the dental office. In an aging population that is becoming wary of the over-prescription of pharmaceuticals which often carry negative and harmful side effects, laser therapy is an effective alternate or adjunctive tool to achieve improved clinical effects. It is a benefit to the patient and dentist to investigate Low Level Laser Therapy, an untapped resource in the dental industry