Journal of Lasers in Medical Sciences

ABSTRACT

Laser has emerged as an adjunct in several treatment modalities in dentistry in the past few decades. This less invasive bladeless technique is bringing revolutionary outcomes in a plethora of periodontal treatment procedures as well. A unique ameliorative approach termed LANAP, described as laser-assisted new attachment procedure was developed by Gregg and McCarthy. In 1990 they introduced an innovative treatment for diseases of gums incorporating pulsed neodymium yttrium aluminum garnet (Nd: YAG) 1064 nm wavelength laser (PerioLase MVP-7). The LANAP concept was endorsed by Yukna et al who conducted a study according to the protocol reinforced at the1996 world workshop in periodontics, which established specific histologic criteria to prove regeneration. Yukna’s histological study found that regeneration of the periodontally compromised root could be achieved by Nd: YAG laser. LANAP facilitates refurbishing of new tissues from supporting structures of the periodontium wherein the unhealthy surface of the roots exhibit pristine attachments in human beings. This paper is a review providing a detailed report of LANAP from its inception to recent advances.

Introduction: The present in vitro study evaluated the recurrence rate of caries following cavity preparations with bur (conventional technique) and irradiation by Erbium:Yttrium–Aluminum–Garnet (Er:YAG) laser through micro hardness test.
Methods: A total of 72 human extracted molars were randomly divided into 3 groups and class 5 cavities were prepared on them with 3 different methods: G1) conventional bur, G2) Er:YAG laser irradiation alone and G3) laser irradiation + laser treatment. The specimens were immersed in the artificial caries solution with pH of 2.0 and 5.0 (12 days) and then immersed in re-mineralizing solution with pH of 7.0 (25 days). The specimens were longitudinally sectioned and their Vickers micro hardness was determined. Data were statistically analyzed by means of three-way analysis of variance (ANOVA) and Tukey multiple comparisons tests.
Results: The micro hardness of the samples was affected by substrate type (enamel and dentin) and low values were achieved in dentin (P < 0.001). Moreover, no significant difference was observed between preparation methods by bar and laser irradiation alone (P ≤ 0.499). Although laser irradiation + laser treatment decreased micro hardness of enamel compared to other methods. In dentin samples, different methods of preparation showed no significant effect on micro hardness (P ≤ 0.874).
Conclusion: Due to the similar values of micro hardness following G1 and G2, it seems that Er:YAG laser alone is as much effective as the conventional bur to prevent recurrence caries. However, because of the high prices of laser instruments, bur preparations can be done commonly.

Introduction: Zirconia bioceramic can be considered for metallic replacement in dental implant applications. A proper method of surface modification may promote better osseointegration.
Methods: In study evaluated viability of fibroblast cell following surface treatment. Therefore, viability L929 cells were characterized using MTT assay and scanning electron microscopy.
Results: The viability assessment determined significant differences A-Y-TZP20 without surface treatment as compared to laser surface treatment (B), laser surface treatment + hydroxyapatite-yttrium stabilized tetragonal zirconia nanocomposite coat (C) and control. This study demonstrated that L929 cells approximately proliferated and spread on A-Y-TZP20 nanocomposite disk in laser surface treatment(B), Laser surface treatment + hydroxiapatite-yttrium stabilized tetragonal zirconia nanocomposite coat (C) groups similar to control group.
Conclusion: Laser surface treatment showed positive effect on the viability of L929 cells.

Introduction: The proper therapeutic plan for medication-related osteonecrosis of the Jaw (MRONJ) is still lacking long-term data up to today. They were several high-technological appliances proposed for the different intervention steps, in addition to tissue repair promoters. The reason for proposing an integrated technique is justified, beyond better compliance of the patients associated to the pain and inflammation reduction and bleeding control, there is also achieving better hard and soft tissues healing.

Methods: Patients diagnosed with bisphosphonates-related osteonecrosis of the jaws (BRONJ) at the Odontostomatology and Maxillo-Facial Surgery Unit of the Hospital of Piacenza undergone surgical intervention. The intervention was performed by using different devices: Piezosurgery for removing the necrotic bone tissue and for obtaining the bone specimen essential for histological analysis; Er:YAG laser (2940 nm) to vaporize necrotic hard tissue until reaching the bleeding bone; platelet-rich plasma (PRP) to stimulate hard and soft tissue healing; and finally diode laser (808 nm) to perform a biostimulation of the surgical site.

Results: All treated patients demonstrated a good postoperative comfort even without using painkillers, no bleeding, and a fast healing process. Most of the patients (92.85%) reached complete healing with a minimum follow up at 6 months. Histological exams demonstrated a good quality without artifacts.

Conclusion: Sequential utilization of different high-technologies devices during all the steps of MRONJ treatment allows to perform a faster and less invasive surgery with a more comfortable postoperative healing process and it may represent a new and original approach for treating this severe adverse event.

Introduction: This study investigated the effect of fractional CO2 laser on shear bond strength (SBS) of resin cement to feldspathic porcelain.
Methods: Sixty blocks of unglazed feldspathic porcelain were randomly divided into 5 groups of 12 by treatment. Group 1 and 2 underwent etching with 9.6% hydrofluoric acid (HF) and air abrasion with alumina particles, respectively. In groups 3 and 4, a fractional CO2 laser was applied for 10 seconds using 20 W/10 mJ (group 3) or 15 W/20 mJ (group 4). The specimens in group 5 were first treated by fractional CO2 laser (15 W/20 mJ) and then etched by HF acid. After silane application, a resin cement (Clearfil SA) was poured into plastic molds over the porcelain surface and light cured. SBS was assessed by a universal testing machine and the type of bond failure was determined.
Results: Analysis of variance (ANOVA) indicated a significant difference in SBS among the study groups (P < 0.001). Pairwise comparison demonstrated that the application of fractional CO2 laser followed by HF acid yielded SBS that was significantly greater than that of the other groups (P < 0.05). The SBS of both laser groups (groups 3 and 4) were comparable to each other and significantly lower than the other groups (P < 0.05). No significant difference was found in the distribution of failure modes among the groups (P = 0.522)
Conclusion: The application of fractional CO2 laser followed by HF acid treatment can improve SBS of resin cement to feldspathic porcelain and could be recommended when demanding extra retention.

Introduction: Porphyromonas gingivalis is one of the major pathogens in the development and progression of periodontal disease. Antimicrobial photodynamic therapy (aPDT) is a new approach which is sorted in non-invasive phototherapy for bacterial elimination. This in vitro study was conducted to compare photodynamic inactivation using Radachlorin and Toluidine blue O (TBO) as photosensitizers on P. gingivalis.
Methods: Bacterial suspensions (200 μL) of P. gingivalis were exposed to either TBO with concentration of 0.1 mg/mL associated with portable light-emitting diode (LED) device (peak wavelength: 630 nm, output intensity: 2.000 mW/cm2, tip diameter: 6.2 mm) or 0.1% Radachlorin® and laser irradiation (InGaAlP, Peak wavelength: 662±0.1% nm, output power: 2.5 W, energy density: 6 J/cm2, fiber diameter: 2 mm). Those in control groups were subjected to laser irradiation or LED alone, Radachlorin® or TBO alone, and one group received neither photosensitizer nor light irradiation. Then counting of colony forming units (CFU) was performed to determine the bactericidal effects in each subgroup.
Results: LED-based aPDT reduced the colony count of P. gingivalis more than that of TBO (P < 0.001) or LED group (P = 0.957). Also, laser-based aPDT had a great reduction in colony count of P. gingivalis in comparison with Radachlorin® (P < 0.001) or laser irradiation alone (P = 0.28). In addition, the colony count reduction of laser-based aPDT was significantly more than LED-based aPDT (P < 0.05).
Conclusion: Considering the results of this study, the viability of P. gingivalis was more affected by the combination of laser and Radachlorin® 0.1% in comparison with LED and TBO 0.1%

Introduction: Polycystic Ovary Syndrome(PCOS), one of the most common causes of infertility. The aim of this study was to investigate the impact of laser acupuncture on PCOS women.

Methods: Twenty-five PCOS women were randomly assigned to either the study group (SG; n= 13), which treated by laser acupuncture, or the control group (CG; n= 12). Blood hormonal levels and insulin resistance at baseline and after 12 weeks of intervention were measured.

Results: The pre intervention showed no statistically significant differences between SG and CG for baseline characteristics ( p>  0.05). After 12 week intervention, Within group analyses showed that BMI, blood hormonal levels and insulin resistance were significantly decreased (p< 0.05), with no significant change in FSH (p> 0.05) in the two groups. Between group analyses showed that all outcomes measures were significantly decreased (p< 0.05) in SG compared to CG, with no significant changes in FSH and BMI(p> 0.05).

Conclusion: Laser acupuncture can be suggested as an effective management for women with polycystic ovarian syndrome.

Introduction: Several experimental studies have displayed positive result for laser radiation on stimulating bone regeneration in recent years. The purpose of this experimental study was to determine low-level laser (LLL) effects on partial bone defects in hypothyroidism male rat.
Methods: Forty male Wistar rats were randomly distributed as below groups: hypothyroidism + laser (Hypo + laser), hypothyroidism (Hypo), and control. Four weeks after surgery, the tibia bone was removed. Biomechanical and histological examinations were performed immediately.
Results: Our results showed significant reduction in the absorption of energy, resistance in bending deformation (bending stiffness), maximum force, high stress load, trabecular bone volume, and number of osteocytes, osteoblasts and osteoclasts in the osteotomy site in hypothyroidism rats compared to hypothyroidism + laser group (P < 0.05).
Conclusion: The results indicated that using laser may improve fracture regeneration and it may accelerate bone healing in hypothyroidism rat.

Introduction: Hirsutism is a condition that affects 10% of women worldwide. In many cultures, hirsutism is regarded as loss of femininity and can be psychologically traumatizing to the suffering females. The aim of the present study was to evaluate how topical capislow would affect or enhance the efficacy of laser hair removal.
Methods: A randomized, monoblinded, placebo controlled split face study of combined topical capislow and long pulsed Nd-YAG laser on one side of the face versus long pulsed Nd-YAG laser alone on the opposite side of the face. Laser sessions were done at 4 weeks interval for maximum seven sessions. Topical capislow and placebo were applied once daily from the day of the first laser session to the day of the last laser session. Patients were evaluated both subjectively and objectively in each laser session and for six months after the last laser session.
Results: Both treatment modalities were well tolerated and accepted with significantly better results in combined capislow and laser group versus laser alone.
Conclusion: Topical capislow can represent a safe and effective synergistic method for laser with faster results but this is a temporary effect retained only to the time of its application.

Introduction: An ulcer is an injury that affects the skin and has many causes. Healing is a way of protecting the body against any infectious agent that tries to infect you through the wound. Low level laser (LLL) in the treatment of ulcers, aims at maintaining the stability of the physiological process of tissue repair and ultrasound (US) acts by increasing the elasticity of tissue and scarring. The aim of this study was to analyze the effects of LLL and US in wound healing of ulcers induced in mice.
Methods: In this experimental study, a sample of 36 guinea pigs was divided into 6 groups of 6 mice, 2 groups as control (C7) and (C14), 2 treated with laser (GL7) and (GL14) and the others 2 treated with ultrasound (GU7) and (GU14). The ulcer was induced and after 7 days, 6 mice from each group were sacrificed to obtain the histological sections for analysis, and the remaining 6 mice from each group continued under treatment and in day 14, they were sacrificed to obtain histologic specimens while macroscopic image was also carried out.
Results: Three aspects were analyzed, the percentage of wound regression where it was observed that there was a significant difference in the first 7 days. Regarding the inflammatory process, it was observed that in the first 7 days GL7 and GU7 improved significantly and within 14 days of the experimental period GU14 showed a significant difference when compared to C14. The number of fibroblasts present in the GL at 7 days showed a significant difference compared to the others, and at 14 days, the US group had a significant difference compared to the other groups.
Conclusion: Thus, it was evident that the US had more effective results with anti-inflammatory action, better organization and increased deposition of collagen and fibroblasts. Therefore, it can be concluded that other studies are consistent with this taking into account the laser must be used during the early days of the initial healing process and the US during the end of this process.

Background: Skin graft is standard therapeutic technique in patients with deep ulcers but as every surgical procedure has complications. Although several modern dressings are available to enhance comfort of donor site, using techniques that accelerate wound healing may enhance patient’s satisfaction.

Low Level Laser Therapy (LLLT) has been used in several medical fields, especially for wound healing but for treating large ulcers, it may last several months to heal completely.

Materials and Methods: The protocols and informed consent were reviewed according to Medical Ethics Board of Shahid Beheshti University of Medical Sciences (IR.SBMU.REC.1394.363) and Iranian Registry of Clinical Trials (IRCT2016020226069N2). Nine patients with bilateral similar grade 3 burn ulcer in both hands or both feet, candidate for Split Thickness Skin Graft (STSG) were selected. One side was selected for laser irradiation and the other side as control, randomly. Laser area was irradiated by red, 655 nm laser light, 150 mW, 2 J/Cm² for the bed of the ulcer and infra red 808 nm laser light, 200 mW for the margins, every day for 7 days.

Results: The rate of wound dehiscence after skin graft surgery was significantly lower in laser treated group in comparison to control group which received only classic dressing (P=0.019).

Discussion: In the present study for the first time we evaluate the effects of LLLT on the healing process of skin grafted area in burn patients. The results showed LLLT is a safe effective method which improves graft survival and wound healing process and decreases the rate of wound dehiscence in patients with deep burn ulcer.

Introduction: It has been suggested that the application of casein phosphopeptide-amorphous calcium phosphate paste (CPP-ACP) and CO2 laser irradiation on enamel could increase the resistance of enamel to caries and acid attacks. The aim of the current study was to compare the influence of CPP-ACP paste application and irradiation of CO2 laser on microhardness of demineralized enamel.
Methods: Thirty sound maxillary extracted premolars were selected. The crowns were cut at the cervical line and were split into facial and palatal halves. Specimens were mounted in self-cure acrylic blocks in such way that the enamel surface was exposed to 4×4 mm. After a pH cycling of the specimens, they were randomly divided into 4 groups (n = 15), as follows: CG: Control group, LAS: CO2 laser, CP: CPP-ACP and LASCP: laser combined CPP-ACP treatment. The Vickers microhardness of the specimens was measured (500 g load, 5 seconds, 3 points). Data were analyzed using one-way ANOVA and post hoc Tukey tests (α = 0.05).
Results: The lowest mean Vickers microhardness value was observed in CG group (192.57±50.87 kg/mm2) and the highest in LASCP group (361.86±22.22 kg/mm2). There were significant differences between groups (P < 0.001). The pairwise comparison of the groups revealed that there were significant differences between these groups: CG versus LAS, CP, LASCP (P < 0.05) and LASCP versus LAS and CP (P < 0.05). No significant difference between LAS group versus CP group (P > 0.05) was observed.
Conclusion: The results of the current study revealed that CO2 laser and CCP-ACP were effective for improvement of enamel hardness value after demineralization. Incorporation of CO2 laser irradiation and CCP-ACP paste application provides additional remineralizing potential for demineralized enamel.

Introduction: Avascular necrosis (AVN) of the femoral head is an increasingly common cause of musculoskeletal disability with unknown etiology. Traumatic and non-traumatic factors can be effective in its occurrence. About 50% of cases are bilateral. The underlying treatment is prosthetic replacement surgical procedure.
Case Presentation: We report a case of bilateral AVN of femoral heads who was a candidate for prosthetic replacement surgery but improved significantly, using laser acupuncture. The patient was a 55-year-old woman with a diagnosis of bilateral osteonecrosis of the femoral head for five years. As the patient declined the surgical option, laser acupuncture was started for pain control. Regarding the signs of bilateral femoral head recovery (according to the MRI scan criteria), a total of 3 courses of laser acupuncture (each course was 20 sessions) with 2 months intervals was performed. Ten acupuncture points: Li4, Li11, St36, SP6, LIV3, GB4, GB5, GB6, GB13, GB14, GB20, GB30, GB31, GB34, were irradiated bilaterally using red 650 nm laser, 100 mW, 1505 Hz frequency, duty cycle 50 3 J/point and near infrared 810 nm laser, 100 mW, 1705 Hz frequency, duty cycle 50 3 J/point, for 2 minutes. The patient received 3 laser therapy courses. During the first-course, laser therapy was done every other day to reduce pain. For the second and third courses, according to pain decrease, therapy was done every week.
Results: The results of the MRI scans and x-ray studies show progressive regeneration of the right femoral head from VI to B II and of the left from V to C II (based on the standard table of Pennsylvania).
Conclusion: It seems that this procedure may be mentioned in future research projects, especially in cases with high risks of surgery.