A comparative histological study of wound healing following Nd:YAG laser with different energy parameters and conventional surgical incision in rat skin

Effect of Nd:YAG laser on bone formation in rat tibia defects: three-dimensional micro-computed tomography image analysis

Nd:YAG laser is in common clinical use for the treatment of tissue incision, transpiration, and haemostasis in soft tissues. However, few studies have reported the effects of low-level laser therapy (LLLT) from Nd:YAG laser on bone healing. The aim of this study was to perform three-dimensional (3D) morphological evaluation of the photobiomodulation of Nd:YAG laser in bone defects in rat tibiae using micro-computed tomography CT (micro-CT) imaging. A bone defect was created in each tibia of 30 rats. The right side was treated with LLLT from Nd:YAG laser (LT group) daily until sacrifice and the left tibiae served as controls (control group). All tibiae underwent micro-CT imaging at 7, 14, and 21 days after the operation. Three-dimensional image analysis of bone volume (BV) and bone surface area (BS) of new bone formation in the defects was performed and histologic analysis was conducted for all tibiae. Tibial BV and BS values were highest in both groups at 7 days after the operation and decreased at 14 days after operation. BV and BS values were both significantly higher in the LT group than in the control group at 7 and 14 days. There was no significant difference between the groups for either metric at 21 days. The present findings demonstrate that Nd:YAG laser simulates bone formation during the early healing period.

Aesthetic Gingival Melanin Pigmentation Treatment in Smokers and Non-Smokers: A Comparison Study Using Nd:YAG Laser and Ceramic Bur

Aesthetic concerns are increasing rapidly; thus, several approaches have been suggested for treating gingival melanin pigmentation. Lasers have been reported as an effective new tool, and the Nd:YAG laser beam has an affinity for melanin and haemoglobin. However, ceramic gingival bur is simple and has less bleeding effect during operation than conventional techniques. This study aimed to compare the outcomes of gingival depigmentation using the Nd:YAG laser and ceramic bur in two different groups (smokers and non-smokers). A total of 40 patients presenting with gingival melanin pigmentation were enrolled in this split-mouth study. The sample was divided into two groups: smokers and non-smokers. Treatment was performed using the Nd:YAG laser (3 W, 60 mJ/pulse, and 50 Hz) and ceramic bur with a one-week interval between the two methods. Clinical indices were recorded, including intraoperative bleeding, wound healing, post-operative pain, and the recurrence of pigmentation, and follow-up periods were determined in the 3rd, 6th, and 9th months postoperatively. Both treatments promoted a similar pain experience and recurrence rate of pigmentation (p > 0.489, p = 1.000, respectively). Bleeding during surgery and complete healing recovery after one week were statistically significantly higher when using ceramic bur (p = 0.00, p = 0.041, respectively). Concerning the effect of smoking on the treatment, a higher recurrence rate was observed in SG than N-SG in laser sites (50%, and 95%, respectively) and bur sites (60%, and 85%, respectively), but statistically no significant difference was observed (p > 0.080). In conclusion, both procedures are adequate for aesthetic gingival depigmentation treatment. The Nd:YAG laser showed greater effectiveness in controlling bleeding, while ceramic bur showed a faster clinical recovery. Furthermore, smokers were more likely to have low depigmentation treatment stability.

Evaluation of wound healing and postoperative pain after oral mucosa laser biopsy with the aid of compound with chlorhexidine and sodium hyaluronate: a randomized double blind clinical trial

OBJECTIVES

The aim of this study is to evaluate secondary intention healing process and postoperative pain of oral soft tissues after laser surgery with the use of a compound containing chlorhexidine and sodium hyaluronate.

MATERIALS AND METHODS

This double-blind, randomized clinical study included 56 patients affected by benign oral lesions and subjected to excisional biopsy with diode laser and randomly divided into three groups. Study group (SG) received 0.2% chlorhexidine digluconate and 0.2% sodium hyaluronate treatment; control group (CG) received 0.2% chlorhexidine digluconate; and placebo group (PG) followed the same protocol, taking a neutral solution having the same organoleptic characteristics. Wound healing was evaluated using percentage healing index (PHI). Numeric rating scale (NRS) was used to evaluate postoperative pain.

RESULTS

PHI (T1 = 7 days) was 67.25% for SG, 58.67% for CG, and 54.55% for PG. PHI (T2 = 14 days) was 94.35% for SG, 77.79% for CG, and 78.98% for PG. A statistically significant difference was between the groups for PHI at T2 p = 0.001. No difference was detectable for pain index.

CONCLUSIONS

A solution containing sodium hyaluronate and chlorhexidine is a good support to increase wound healing by secondary intention after laser biopsy, but no differences were in postoperative perception of pain.

CLINICAL RELEVANCE

The use of the tested solution can be recommended after laser oral biopsies, to achieve a healing without suture. About the postoperative pain, the compound has not showed the same results and did not have measurable effects.

Periodontal and peri-implant wound healing following laser therapy

Laser irradiation has numerous favorable characteristics, such as ablation or vaporization, hemostasis, biostimulation (photobiomodulation) and microbial inhibition and destruction, which induce various beneficial therapeutic effects and biological responses. Therefore, the use of lasers is considered effective and suitable for treating a variety of inflammatory and infectious oral conditions. The CO2 , neodymium-doped yttrium-aluminium-garnet (Nd:YAG) and diode lasers have mainly been used for periodontal soft-tissue management. With development of the erbium-doped yttrium-aluminium-garnet (Er:YAG) and erbium, chromium-doped yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers, which can be applied not only on soft tissues but also on dental hard tissues, the application of lasers dramatically expanded from periodontal soft-tissue management to hard-tissue treatment. Currently, various periodontal tissues (such as gingiva, tooth roots and bone tissue), as well as titanium implant surfaces, can be treated with lasers, and a variety of dental laser systems are being employed for the management of periodontal and peri-implant diseases. In periodontics, mechanical therapy has conventionally been the mainstream of treatment; however, complete bacterial eradication and/or optimal wound healing may not be necessarily achieved with conventional mechanical therapy alone. Consequently, in addition to chemotherapy consisting of antibiotics and anti-inflammatory agents, phototherapy using lasers and light-emitting diodes has been gradually integrated with mechanical therapy to enhance subsequent wound healing by achieving thorough debridement, decontamination and tissue stimulation. With increasing evidence of benefits, therapies with low- and high-level lasers play an important role in wound healing/tissue regeneration in the treatment of periodontal and peri-implant diseases. This article discusses the outcomes of laser therapy in soft-tissue management, periodontal nonsurgical and surgical treatment, osseous surgery and peri-implant treatment, focusing on postoperative wound healing of periodontal and peri-implant tissues, based on scientific evidence from currently available basic and clinical studies, as well as on case reports.

Lasers and the treatment of chronic periodontitis

For many intraoral soft-tissue surgical procedures the laser has become a desirable and dependable alternative to traditional scalpel surgery. However, the use of dental lasers in periodontal therapy is controversial. This article presents the current peer-reviewed evidence on the use of dental lasers for the treatment of chronic periodontitis.

Submucosal glycerol injection-assisted laser surgical treatment of oral lesions

Recently, we modified laser surgery for superficial lesions in the oral cavity by using submucosal glycerol injection. This procedure was based on a technique for endoscopic mucosal resection (EMR) in the gastrointestinal tract. The aim of this study was to evaluate the effectiveness of the modified laser surgery assisted by a submucosal glycerol injection. Eleven superficial oral lesions in ten patients were treated with diode laser (continuous wave mode, 3 W) after a submucosal injection of glycerol solution. Injection of glycerol solution created mucosal expansion, which enabled the procedures to be done without bleeding, over cutting, over coagulation and unintended irradiation. The surface of the wounds showed little carbonization, resulting in good healing. Submucosal glycerol injection for laser treatment in the oral cavity is a promising technique for treating superficial oral lesions by virtue of less invasion and good results.

Lasers in periodontics: a review of the literature

BACKGROUND

Despite the large number of publications, there is still controversy among clinicians regarding the application of dental lasers to the treatment of chronic periodontitis. The purpose of this review is to analyze the peer-reviewed research literature to determine the state of the science concerning the application of lasers to common oral soft tissue problems, root surface detoxification, and the treatment of chronic periodontitis.

METHODS

A comprehensive computer-based search combined the following databases into one search: Medline, Current Contents, and the Cumulated Index of Nursing and Allied Health. This search also used key words. In addition, hand searches were done for several journals not cataloged in the databases, and the reference lists from published articles were checked. All articles were considered individually to eliminate non-peer-reviewed articles, those dealing with commercial laser technology, and those considered by the author to be purely opinion articles, leaving 278 possible articles.

RESULTS

There is a considerable conflict in results for both laboratory studies and clinical trials, even when using the same laser wavelength. A meaningful comparison between various clinical studies or between laser and conventional therapy is difficult at best and likely impossible at the present. Reasons for this dilemma are several, such as different laser wavelengths; wide variations in laser parameters; insufficient reporting of parameters that, in turn, does not allow calculation of energy density; differences in experimental design, lack of proper controls, and differences in severity of disease and treatment protocols; and measurement of different clinical endpoints.

CONCLUSIONS

Based on this review of the literature, there is a great need to develop an evidence-based approach to the use of lasers for the treatment of chronic periodontitis. Simply put, there is insufficient evidence to suggest that any specific wavelength of laser is superior to the traditional modalities of therapy. Current evidence does suggest that use of the Nd:YAG or Er:YAG wavelengths for treatment of chronic periodontitis may be equivalent to scaling and root planing (SRP) with respect to reduction in probing depth and subgingival bacterial populations. However, if gain in clinical attachment level is considered the gold standard for non-surgical periodontal therapy, then the evidence supporting laser-mediated periodontal treatment over traditional therapy is minimal at best. Lastly, there is limited evidence suggesting that lasers used in an adjunctive capacity to SRP may provide some additional benefit.

Parotid Surgery Using Nd:YAG Laser Contact Tips: Clinical Assessment of Perioperative Facial Nerve Function

OBJECTIVE

The objective of this paper is to review 51 consecutive contact Nd:YAG laser parotidectomies to determine perioperative outcomes and complications related to the facial nerve and the use of the laser tips.

BACKGROUND DATA

Parotid surgery is mostly performed with scalpel or scissors, techniques that may put the facial nerve at risk for injury due to brisk bleeding and imprecise dissection. Even though previous experiences with Nd:YAG lasers in surgery had raised concerns of energy dispersion, the contact sapphire tips used in this series allowed accurate precise dissection and hemostasis, limiting complications.

MATERIALS AND METHODS

Close facial nerve dissection was done at 8-12 watts, for an average total of 8,000-12,000 joules per case.

RESULTS

No significant or permanent facial nerve complications resulted from the use of the laser tips, except for expected transient and reversible postoperative ipsilateral marginal mandibular nerve paresis observed in 43% of the patients-less than the generally quoted 50% expected after uneventful lateral lobe parotidectomy.

CONCLUSION

This review concludes that the contact Nd:YAG laser may offer significant technical and safety advantages, and no direct associated complications in the dissection and preservation of the facial nerve in parotidectomy.

Can thermal lasers promote skin wound healing?

Lasers are now widely used for treating numerous cutaneous lesions, for scar revision (hypertrophic and keloid scars), for tissue welding, and for skin resurfacing and remodeling (wrinkle removal). In these procedures lasers are used to generate heat. The modulation of the effect (volatilization, coagulation, hyperthermia) of the laser is obtained by using different wavelengths and laser parameters. The heat source obtained by conversion of light into heat can be very superficial, yet intense, if the laser light is well absorbed (far-infrared:CO(2) or Erbium:Yttrium Aluminum Garnet [Er:YAG] lasers), or it can be much deeper and less intense if the laser light is less absorbed by the skin (visible or near-infrared). Lasers transfer energy, in the form of heat, to surrounding tissues and, regardless of the laser used, a 45-50 degrees C temperature gradient will be obtained in the surrounding skin. If a wound healing process exists, it is a result of live cells reacting to this low temperature increase. The generated supraphysiologic level of heat is able to induce a heat shock response (HSR), which can be defined as the temporary changes in cellular metabolism. These changes are rapid and transient, and are characterized by the production of a small family of proteins termed the heat shock proteins (HSP). Recent experimental studies have clearly demonstrated that HSP 70, which is over-expressed following laser irradiation, could play a role with a coordinated expression of other growth factors such as transforming growth factor (TGF)-beta. TGF-beta is known to be a key element in the inflammatory response and the fibrogenic process. In this process, the fibroblasts are the key cells since they produce collagen and extracellular matrix. In conclusion, the analysis of the literature, and the fundamental considerations concerning the healing process when using thermal lasers, are in favor of a modification of the growth factors synthesis after laser irradiation, induced by an HSR. An extensive review of the different techniques and several clinical studies confirm that thermal lasers could effectively promote skin wound healing, if they are used in a controlled manner.