Abstract
I
Thirteen years later, the situation is different. With ∼3500 PubMed abstracts, many of these being dentally oriented, LPT is gradually being implemented in the dental profession. Manufacturers of “hard dental lasers” have realized the shift and are often offering LPT options in their equipment via separate handpieces. With this positive change at hand, it could be a good time to consider the future development of dental LPT, and to further discuss steps necessary to embrace this treatment modality.
The literature is ambiguous when it comes to the protocols, and meta-analyses are hard to evaluate, either because of the lack of reporting of the full parameters or the variation in treatment protocols, for example, in the case of temporomandibular disorder (TMD), for which the diversity of protocols makes a strict scientific evaluation impossible. 2,3 However, this problem is not typical of LPT. It also applies to endodontics, in which there is no evidence-based science, in spite of the fact that it is widely used and quite successful. 4 In addition, there appears to be a lack of qualified reviewers in the area of LPT. Studies with incomplete or incorrect reporting of parameters slip through the reviewing process all too often and there is apparently a lack of understanding of the therapeutic windows when it comes to meta-analyses. Reviewing focuses too much on methodology and the use of unlikely laser parameters is not well considered. Even qualified reviewers call for improvement in LPT parameter reporting. 5 The World Association for Laser Therapy has published dosage guidelines for musculoskeletal indications, 6 but so far not for dental applications. Scientific journals could require a higher reviewing standard, and even specialized laser journals do not require full reporting of the parameters used.
“Laser dentistry” in the past generally meant drilling, cutting, and vaporizing, but there is now an understanding of the fact that even a “surgical” laser produces some degree of LPT. There is also a growing awareness among manufacturers that LPT is an attractive accessory to their traditional lasers. Diode lasers are easily fitted with a reduced power LPT headpiece, and Nd:YAG manufacturers recommend the bleaching array as a way of performing LPT. This progress is positive, although the therapist has little control of the parameters, unless the average output in milliwatts and aperture size are accounted for. From manufacturers specializing in LPT, products have emerged in which a single portable probe contains two wavelengths and/or the ability to change the power. This makes these products more versatile. Holding a laser pen and aiming at selected targets is the most common treatment procedure. This is suitable in several situations, but there is a need for development of more convenient and time-saving procedures; for example, an impression tray-like design with a red light in periodontal therapy and orthodontics, a mask covering the involved muscles in TMD, or extraoral wraps for mucositis patients.
Meanwhile, parts of the industry offer pseudoscientific explanations, which confuse and delay the full recognition of LPT. Another problem is that some manufacturers recommend LPT in the watt range and speak about kiloJoules. High energies are fine for temporary pain reduction, but certainly not for stimulation.
LEDs have been suggested as a replacement for lasers, and many studies have confirmed the efficacy of both light sources. Some studies have compared the effects of lasers and LEDs in dental applications and have confirmed the usefulness of both. However, the light parameters have been too different to make any conclusions possible. 7 It appears that the effects of LEDs are more similar to lasers when used for superficial structures, whereas lasers are more effective in the treatment of bulk tissues. 8
Dental LPT is on the threshold of entering from the shadows and into the evidence-based light, but the lack of easily accessible independent and unbiased education needs to be resolved. Universities are called upon to take the lead and not to let their students depend upon information from the industry. Karu (unpublished observation) said that “we can talk to the cells, but we need to learn their language.” For the time being we can only communicate via some kind of pidgin, but that is still wonderful.
In conclusion, the scientific base and overall reputation of dental LPT has improved considerably during the past 12 years. However, studies of higher quality are needed to reach the evidence-based level for most of the indications. LPT is a phenomenon that works for all cells containing mitochondria, and the beauty of the treatment is that is works for so many conditions. This has also become a problem from a scientific point of view, as >100 different indications are described in the literature, and very few have enough literature backing to be considered evidence based. But when evaluating an indication, one should not only look at the studies published for this particular indication. Rather, the biological background of the pathology should be considered, and the global effects of LPT taken into account. And the lack of side effects is a very important aspect, in a time when overconsumption of nonsteroidal anti-inflammatory drugs (NSAIDs) and steroids has become a serious health problem. A recent survey of the literature revealed 23 studies in which LPT was nearly as effective or better than the pharmaceuticals, or even better when used in combination with them. 9 Dentists requiring more evidenced-based science before introducing LPT might find the reference 10 worthwhile reading.