October 2015 LITERATURE REVIEW

Compiled by Dr Igor Cernavin, Prosthodontist, Honorary Senior Fellow University of Melbourne School of Medicine, Dentistry and Health Sciences, Director and Cofounder of the Asia Pacific Institute of Dental Education and Research (AIDER), Australian representative of World Federation of Laser Dentistry (WFLD).

Ozkocak et al1 evaluated the bond strength of various root canal sealers after various irrigation solutions and Er:YAG laser irradiation were used on root canal dentin. The highest adhesion was observed in EDTA groups.

de Oliveira and coworkers2 carried out a retrospective study to evaluate the effectiveness of laser therapy for acceleration and recovery of nerve sensitivity after orthognathic or minor oral surgery by analysis of clinical records of patients treated at the Special Laboratory of Lasers in Dentistry (LELO, School of Dentistry, University of Sao Paulo), throughout the period 2007-2013. The authors found that low- power laser therapy with a beam emission band in the infrared spectrum (808nm) can positively affect the recovery of sensitivity after orthognathic or minor oral surgery.

Amini et al3 evaluated the effect of laser irradiation on bone regeneration in the midpalatal suture concurrent with rapid palatal expansion in rats. Laser therapy was done using a gallium-aluminum-arsenide diode laser with 810 nm wavelength and 4 J/cm(2) irradiation in days 0, 2, 4, 6, 8, 10, 12, 14 in 4 points (1 labial and 3 palatal). They concluded that low-level laser irradiation can increase and accelerate bone regeneration in the midpalatal suture after rapid palatal expansion and hence reduce retention time.

Fornaini, Carlo and coworkers4 compared in an animal model, the thermal elevation induced by four different laser wavelengths (diode, Nd:YAG, Er:YAG, KTP) during implant uncovering. The abstract is reproduced in full.

The implant surgery consists of two distinct techniques, the transmucosal, also known as “one-stage” and the “two-stage” technique. Lasers represent a possible aid in implant dentistry, especially in the two-stage technique and its main characteristics are represented by a decreased trauma to bone and soft tissues, a reduction of pain as well as a reduction of the risk of postoperative infections. The aim of this study was to analyze in an animal model the thermal elevation induced by four different laser wavelengths (diode, Nd:YAG, Er:YAG, KTP) during the implant uncovering. Four pig jaws were used to carry out this study. Five implants were placed in each anatomical specimen for a total of 20 fixtures. Four wavelengths (532, 810, 1,064 and 2,940nm) were used to uncover the implants. Two thermocouples were used to measure temperature changes during laser irradiation at bone level, peri-implant tissues and on the fixture surface The thermocouples were connected with two probes of 1.5mm in diameter, in order to simultaneously record two temperature variations. Surface temperature was also checked during all procedures with a thermal camera (Thermovision A 800, Flyr Systems, Stockolm, Sweden) connected to a PC. The mean temperatures of each specimen (five fixtures) were calculated (TM1, mean temperature at the beginning; TM2, mean peak temperature). Furthermore, a record of the temperature at 1min after the end of the surgical procedure was taken (mean: TM3). All the recorded values were statistically evaluated by one-way analysis of variance (ANOVA). The thermocouples recorded a lower increase in temperature for Er:YAG and KTP laser; Nd:YAG and diode laser produced similar increases characterized by higher values. The thermo-camera pointed out the lower increase for Er:YAG and higher for diode laser. KTP laser resulted in faster uncovering of implants and diode laser was the one that needed more time. This ex vivo study showed that laser utilization with the recommended parameters gives no risks of dangerous themal elevation to the tissues and implants.

Teixeira et al5 evaluated the influence of low-level lasers on the early stages of osseointegration. They used 24 J/cm(2) of gallium-aluminum-arsenide laser over 15 days and found that Low-level laser had no significant short-term effect on bone-to-implant contact and removal torque values regardless of implant surface characteristics. Time was the only variable presenting significant differences between measurements.

van As, Glenn A6 have commenced a review of lasers in implant dentistry. Part 1 is published in Dentistry Today.

Schwendicke and coworkers7 evaluated the cost-effectiveness of preventing and treating peri-implantitis and found that the most effective options included bone grafts, membranes, and laser treatment.

Shi et al.8 evaluated the analgesic effect of low level laser therapy (LLLT) after placement of the orthodontic separators and concluded that the LLLT has a good analgesic effect at 6h, 1d, 2d, 3d after placement of separators which is of statistical significance. However, at 2h, 4d, 5d after the placement, although the results tended to support LLLT, they were not statistically significant.

Kripal and coworkers9 published an overview of iatrogenic damage to the periodontium caused by laser.

Cairo et al10 wrote a review examining the evidence for optimal timing for classic regenerative approaches (demineralized freeze-dried bone allograft [DFDBA], GTR, and GTR combined with graft materials), laser-assisted regeneration (LAR), enamel matrix derivatives (EMD) (EMD alone, EMD versus GTR, and EMD combination), and recombinant human platelet-derived growth factor BB (rhPDGF-BB) in relation to regenerative treatment of intrabony defects in orthodontic and endodontic therapy.

Seoane and coworkers11 examined the process of epithelial repair in a surgical wound caused by diode laser. They concluded that early re-epithelisation occurs slightly faster when a conventional scalpel is used for incision, although re-epithelisation is completed in two weeks no matter which instrument used. In addition, pseudoepitheliomatous hyperplasia is a potential event after oral mucosa surgery with diode laser. They point out that knowledge about this phenomenon, which has not been described previously may prevent diagnostic mistakes and inadequate treatment approaches, particularly when dealing with potentially malignant oral lesions.

Diniz et al12 examine the effect of antibacterial photodynamic therapy using 0.025g/mL methylene blue with a 5min pre-irradiation time and a continuous-wave diode laser (660nm, 0.04cm(2) spot size, 40mW, 60s, 60J/cm(2) and 2.4J. They concluded that antibacterial photodynamic therapy may be considered a promise adjunctive therapy for deep carious lesions.

Levine Robert13 writes about the CO2 laser use in operculectomy. The abstract is reproduced in full.

The 10,600-nm CO2 laser is both an efficient and spatially precise photo-thermal ablation device and excellent coagulator because of the close match between its coagulation depth and the diameters of oral soft-tissue capillaries. The ablation of hyperplastic oral soft tissue with the flexible fiber waveguide 10,600-nm CO2 laser is a minimally invasive and typically suture-free surgical modality that ensures dependable treatment. It is, in many respects, superior to most of the alternative treatment options. Its excellent hemostatic abilities and the minimal damage to adjacent healthy tissues make the CO2 laser a perfect surgical tool for treating oral soft-tissue lesions, including the inflamed operculum.

References
1. Ozkocak, Ismail; Sonat, Bade. Evaluation of Effects on the Adhesion of Various Root CanalSealers after Er:YAG Laser and Irrigants Are Used onthe Dentin Surface. Journal of endodontics, 41 (8):1331-6; 10.1016/j.joen.2015.03.004 2015-Aug.
2. de Oliveira, Renata Ferreira; da Silva, Alessandro Costa; Simoes, Alyne; Youssef, Michel Nicolau; de Freitas, Patricia Moreira. Laser Therapy in the Treatment of Paresthesia: A Retrospective Study of 125 Clinical Cases. Photomedicine and laser surgery, 33 (8):415-23; 10.1089/pho.2015.3888 2015-Aug.
3. Amini, Fariborz; Najaf Abadi, Maryam Pirmoradian; Mollaei, Mobina.
Evaluating the effect of laser irradiation on bone regeneration in midpalatal suture concurrent to rapid palatal expansion in rats.
Journal of orthodontic science, 4 (3):65-71; 10.4103/2278-0203.160237 2015 Jul-Sep.
4. Fornaini, Carlo; Merigo, Elisabetta; Vescovi, Paolo; Bonanini, Mauro; Antonietti, Walter; Leoci, Luca; Lagori, Giuseppe; Meleti, Marco. Different laser wavelengths comparison in the second-stage implant surgery: an ex vivo study. Lasers in medical science, 30 (6):1631-9; 10.1007/s10103-014-1623-3 2015-Aug.
5. Teixeira, Eduardo Rolim; Torres, Marco Antonio Rambo Osorio; Meyer, Kleber Ricardo Monteiro; Zani, Sabrina Rebollo; Shinkai, Rosemary Sadami Arai; Grossi, Marcio Lima. The Influence of Low-Level Laser on Osseointegration Around Machined and Sandblasted Acid-Etched Implants: A Removal Torque and Histomorphometric Analyses. The Journal of oral implantology, 41 (4):407-13; 10.1563/AAID-JOI-D-13-00097 2015-Aug.
6. van As, Glenn A. Lasers in Implant Dentistry, Part I.
Dentistry today, 34 (7):134, 136-9; 2015-Jul.
7. Schwendicke, Falk; Tu, Yu-Kang; Stolpe, Michael. Preventing and Treating Peri-Implantitis: A Cost-Effectiveness Analysis. Journal of periodontology, 86 (9):1020-9; 10.1902/jop.2015.150071 2015-Sep.
8. Shi, Quan; Yang, Shuo; Jia, Fangfang; Xu, Juan. Does low level laser therapy relieve the pain caused by the placement of the orthodontic separators? – A meta-analysis. Head & face medicine, 11 (1):28; 10.1186/s13005-015-0085-6 2015 Aug 28.
9. Kripal, Krishna; Sirajuddin, Syed; Rafiuddin, Syed; Mp, Rakesh; Chungkham, Sachidananda. Iatrogenic Damage to the Periodontium Caused by Laser: An Overview. The open dentistry journal, 9 210-3; 10.2174/1874210601509010210 2015.
10. Cairo, Francesco; Pagliaro, Umberto. Regenerative Therapies in the Treatment of Intrabony Defects Show High Clinical Efficacy. The journal of evidence-based dental practice, 15 (3):108-12; 10.1016/j.jebdp.2015.07.004 2015-Sep.
11. Seoane, J; Gonzalez-Mosquera, A; Garcia-Martin, J-M; Garcia-Caballero, L; Seoane-Romero, J-M; Varela-Centelles, P. Pseudoepitheliomatous hyperplasia after diode laser oral surgery. An experimental study. Medicina oral, patologia oral y cirugia bucal, 20 (5):e554-9; 2015 Sep 01.
12. Diniz, Ivana Marcia Alves; Horta, Ivay Diniz; Azevedo, Cynthia Soares; Elmadjian, Thais Regina; Matos, Adriana Bona; Simionato, Maria Regina Lorenzetti; Marques, Marcia Martins. Antimicrobial photodynamic therapy: A promise candidate for caries lesions treatment. Photodiagnosis and photodynamic therapy, 12 (3):511-8; 10.1016/j.pdpdt.2015.04.006 2015-Sep.
13. Levine, Robert. Laser-Assisted Operculectomy. Compendium of continuing education in dentistry (Jamesburg, N.J. : 1995), 36 (8):561-8; 2015-Sep.

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