The purpose of this article is to describe the use of the erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr: YSGG) laser (Biolase Technology) in various implant-related surgical procedures. Clinical cases demonstrating use of the laser are presented, and clinical advantages as observed by the author when compared to scalpel surgery are discussed.
The acronym LASER stands for light amplification by stimulated emission of radiation. Since Maimon1 developed the ruby laser in 1960, lasers have slowly integrated into the dental world. Today, they have FDA approval for cutting bone, enamel, dentin, and soft tissue. Lasers have been approved and used for endodontics, periodontics, oral surgery, restorations, lesion removal, and desensitization. Advantages of the laser with soft tissues are reduction in bleeding, postoperative pain, swelling and edema, and precise coagulation and cutting. The advantages of the laser in cutting bone include being gentler than bone saws or high-speed drills, less postoperative pain and swelling, less necrosis of surrounding tissue, minimal trauma due to heat transfer, and no trauma to the periosteum when removing bone for grafting.2-4 Advantages of laser use in endodontics5 are disinfection of canals (more than 1,000 µm),6 leaving open dentinal tubules, and reduction of postoperative pain and swelling.
Why not lasers in implant dentistry? The laser can seal blood vessels, lymphatic vessels, and nerve fibers. It can reduce mechanical trauma and bacterial counts.7 It is a more precise tool than a surgical handpiece,8 has antisepsis qualities, and reduces trauma during the procedure.
Laser energy is developed by directing photons into a medium that excites the electrons to an elevated energy level. In the excited state, if the electron absorbs yet another photon, the electron is elevated to yet a higher and unstable energy state. As the excited state electron decays to an equilibrium state, 2 photons or quanta of light are emitted. These photons are then monochromatic (the same wavelength), coherent (the photon wavelengths are in synchrony), and are highly collimated (traveling in the same direction). The laser energy produced is a monochromatic, coherent, and collimated beam.
The laser energy from the Er,Cr:YSGG laser is in the infrared wave spectrum. The laser beam is directed at a target tissue with a fiber-optic delivery system attached to a handpiece and is then emitted in pulses. In this laser the photon amplification occurs through a medium of heterogeneous crystals (YSGG). This laser emits photons at a 2,780-nm wavelength and a pulse duration of 140 microseconds in the repetition rate that can vary from 10 Hz to 50 Hz. During surgical procedures, the power output for alveolar bone is 3.5 W 30 Hz, yielding an energy density of 8.6 J/cm2, and the power output for gingival tissue is 1.25 W 30 Hz, yielding an energy density of 24 J/cm2. The sapphire tip has a diameter of 750 µm. During the surgical procedure, the sapphire end-cutting tip is approximately 2 mm from the target tissue.
Cutting hard/soft tissues is a complex interaction of laser energy with water and the tissues (hydrophotonics).9 When tissues interact with laser energy, the effect is influenced by the emission wavelength, tissue optical properties, time of exposure, laser energy, and absorption of the laser energy into the tissues. The absorptive effect is the key as to how the target tissue’s atoms and molecules convert laser light energy into heat, chemical, acoustic, or nonlaser light energy. Thus, the amount of laser energy needed to produce desired results varies depending on the tissue involved.
RELATED USE IN IMPLANT DENTISTRY FLAP SURGERY
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Figure 1. Twenty-year-old female, 4-day postoperative photo of full bony extraction in site No. 32. |
Use of the YSGG laser nearly eliminates hemorrhaging with reflection of tissues, normally at settings of 1.25 W 30 Hz 3/11 (water/air ratio for the Waterlase MD). It has been shown that the YSGG laser device is selectively absorbed in the target tissue and may result in either a direct tissue cut (cold cut) or vaporization of the water within a cell, causing rupture (thermal cut), a process known as thermal-mechanical tissue ablation.10 The thermal-mechanical tissue ablation limits the amount of collagen damage to as little as 5 µm (approximately 2 cell widths), leaving the extracellular collagen matrix less affected. There is also reportedly less histamine release in tissues treated with a laser device, which accounts for the lessening or absence of intraoperative and postoperative pain and inflammation. Furthermore, there has been virtually no scarring and minimal tissue shrinkage on crestal, sulcular incisions. Reports indicate that there is 0.5 mm of tissue shrinkage with a laser, compared to 3 mm with a Bard Parker, including extremely fast healing.11 The procedure may or may not be as fast, but the benefits postoperatively are a major plus for the patient. The average patient pain rating has been reported to be a 1 or 2 on a scale of zero to 10, with zero being no pain and 10 being unbearable pain; 5% or less had a rating of 4 or 512 (Figure 1).
SINUS LIFT PROCEDURES13-15
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Figure 2a. Five days postoperatively, 58-year-old female. . |
Figure 2b. Eighteen days postoperatively on suture removal appointment. |
One of the major problems associated with sinus lift procedures, as per surgical protocol by O. Hilt Tatum Jr, is primary closure. If not achieved, it can cause dehiscence and failure of the graft. To aid in preventing this, Dr. Michael Pikos16 recommends using a resorbable membrane over the oval window. What this author has seen is the ability of the tissue to maintain its elastic effect after flap preparation. It has become rare to release tissue to achieve primary closure, thus eliminating much postoperative bruising, swelling, and pain, and significantly improving healing time.
Another difficult procedure of the sinus lift is the osteotomy of the lateral oval window. No matter how careful or skilled the clinician is, it is always possible to perforate the membrane, either in the cutting of the window or initial elevation of the membrane. Due to the free movement of air in and out of the maxillary sinus, the YSGG laser will not cut the membrane.17 It becomes a matter of making an oval shape to the surgeon’s desire, using settings of 3.5 W 30 Hz 30/60 until the lateral wall is released from the membrane. The bone can then be peeled from the membrane (save for bone graft material) and provide great access to elevate a nonperforated membrane.
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Figure 3a. Day of surgery, 67-year-old female. |
Figure 3b. Seven days postoperatively. |
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Figure 3c. Fourteen days on suture removal appointment. |
With the cut, using the YSGG laser, patients will not experience the postoperative pain associated with necrosis of the lateral wall. In addition, the author has observed that healing takes place in a matter of days as compared to weeks when traditional rotary drills are used to cut bone and Bard Parkers used to reflect tissue (Figures 2a to 2b and 3a to 3c).
BLOCK GRAFTING18-20
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Figure 4a. Day of surgery, 17-year-old female. |
Figure 4b. Day of surgery. |
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Figure 4c. Day of surgery. |
Figure 4d. Twelve days postoperatively on suture removal appointment. |
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Figure 4e. Twelve days postoperatively on suture removal appointment. |
Block grafting, as outlined by Misch and Pikos, can be taken from the ascending ramus or in the symphysis areas. The major problems associated with this procedure are the necrosis of bone and surrounding tissue from the donor site. The patient experiences pain, swelling, phantom “woody tooth” syndrome, limited paresthesia, wound scarring, and tissue recession. In addition, the clinician has difficulty achieving primary closure.
With the use of the YSGG laser, the aforementioned problems can be eliminated. Tissue reflecting has already been discussed, but use of the YSGG laser to cut osteotomy has made this procedure extremely easy for postoperative healing.21 Use of the laser is entirely an end-cutting device. There is no tactile sensation with laser use because the laser is a noncontact surgical instrument. The laser will ablate osseous tissues efficiently at approximately 1.5-mm depths. The head moves in a slow, precise pattern. Once the outline of the osteotomy is made, the laser cuts are progressively deepened into the cancellous bone. The outline is completed with the use of a surgical rotary handpiece to gain total feel of the graft, and then the graft is removed by a straight chisel. The cuts are narrower using the YSGG laser as compared to traditional methods.
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Figure 5a. Day of surgery, 56-year-old male. |
Figure 5b. Day of surgery. |
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Figure 5c. Four days postoperatively. |
Figure 5d. Fourteen days postoperatively. |
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Figure 5e. Fourteen days postoperatively. |
Postoperatively, one observes a dramatic increase in healing and decrease in swelling and pain, thus shifting from a procedure that traditionally causes a high degree of pain to one with less postoperative problems than surgical extraction of a tooth.
We see no scarring, no recession of the donor site, easy manipulation of tissue in the graft site, and easy manipulation to gain primary closure with no releasing of tissue. Again, observed healing time is significantly reduced (Figures 4a to 4e and 5a to 5e).
IMPLANT PLACEMENT
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Figure 6a. Day of surgical placement and tissue punch technique, 58-year-old female. |
Figure 6b. Nineteen days postoperatively. |
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Figure 7a. Day of surgical placement and tissue punch technique, no sutures, 18-year-old female. |
Figure 7b. Five days postoperatively. |
Using the YSGG laser, as expected, decreases the amount of postoperative pain. In fact, the majority of patients experience very minor amounts of discomfort, 1 to 2 on a scale of zero to 10. A number of patients respond that they took their initial dose of analgesics but never experienced any pain; consequently, they did not take any other pain medication after placement. There are obvious advantages when using the laser with a flap procedure and initial osteotomy, as discussed previously; but in 2-stage implants, this author actually experienced increased Periotest (Medizintechnik Golden) values. In areas where the normal Periotest range was -3, it increased to -5 to -6. For areas in the symphysis, where normal range was -6, it increased to -8. All Periotest values increased 40% when compared to nonlasered areas.
What was done to achieve results was a single use with a setting of 0.5 W 20 Hz 3/8 used in such a way that the laser tip is initiated at the apex of the osteotomy site and then moved up coronally in a counterclockwise pattern. Using this technique appears to start the RAP phenomenon to increase the amount of fibroblasts forming in the area.18, 21-25 This is why I believe my Periotest values have increased (more bone-to-implant contact). This effect has only happened with the 2-stage technique. Immediate-load implant Periotest values have not shown the increased values.
In today’s computer preplanned cases, using a laser with the tissue punch technique for immediate load has made implants easier and has maintained tissue levels comparable to nonsurgical sites. This is making anterior single-implant cases more aesthetic with more attached tissue surrounding the implant (Figures 6a to 6b and 7a to 7b).
CONCLUSION
In the cases described, the YSGG laser was used as the surgical modality. Use of the YSGG laser may not have increased productivity in these cases, but it enhanced postoperative comfort for the patients. There are reports of varied healing with the laser, including reports that histologically, laser wounds heal slightly slower than scalpel wounds. However, this author and my staff have observed that soft-tissue healing was dramatically increased when using the laser (compared to when the scalpel is used), with no morbidity of bone.
References
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4. Wang X, Ishizaki NT, Suzuki N, et al. Morphological changes of bovine mandibular bone irradiated by Er,Cr:YSGG laser: an in vitro study. J Clin Laser Med Surg. 2002;20:245-250.
5. Matsumoto K. Lasers in endodontics. Dent Clin North Am. 2000;44:889-906.
6. Moritz A, Jakolitsh S, Goharkhay K, et al. Morphologic changes correlating to different sensitivities of Escherichia coli and enterococcus faecalis to Nd:YAG laser irradiation through dentin. Laser Surg Med. 2000;26:250-261.
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10. Kimmel AI, Rizoiu IM, Eversole LR. Phase doppler particles analysis of laser energy exploding water droplets. Presented at: International Laser Congress: Lasers at the Dawn of the Third Millennium; September 25-28, 1996; Athens, Greece. Abstract 67.
11. Pumphrey DW. Creating the esthetic anterior implant. Lecture presented at Hinman Dental Meeting. 2004.
12. Hedny J. Painless free gingival graft procedure using an Er,Cr;YSGG laser. Contemp Esthetics. 2005;9:34-37.
13. Tatum OH. Lecture presented at Alabama Implant Study Group. 1977.
14. Tatum H Jr. Maxillary and sinus implant reconstructions. Dent Clin North Am. 1986;30:207-229.
15. Misch CE. Maxillary sinus augmentation for endosteal implants: organized alternative treatment plans. Int J Oral Implantol. 1987;4:49-58.
16. Pikos MA. Maxillary sinus membrane repair: report of a technique for large perforations. Implant Dent. 1999;8:29-34.
17. Miller R. Advanced applications in the YSGG laser for bone and implants. Lecture presented at World Clinical Laser Institute; San Diego, Calif; 2005.
18. Misch CM. Ridge augmentation using mandibular ramus bone grafts for the placement of dental implants: presentation of a technique. Pract Periodontics Aesthet Dent. 1996;8:127-135.
19. Misch CM. The use of ramus grafts for ridge augmentation. Dent Implant Update. 1998;9:41-44.
20. Pikos MA. Alveolar ridge augmentation using mandibular block grafts: clinical update. Alpha Omegan. 2000;93:14-21.
21. Lee CYS. Procurement of autogenous bone from the mandibular ramus with simultaneous third-molar removal for bone grafting using the Er,Cr:YSGG laser: a preliminary report. J Oral Implantol. 2005;31:32-38.
22. Pereira AN, Eduardo Cde P, Matson E, et al. Effect of low-power laser irradiation on cell growth and procollagen synthesis of cultured fibroblasts. Lasers Surg Med. 2002;31:263-267.
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25. Schindl A, Merwald H, Schindl L, et al. Direct stimulatory effect of low-intensity 670 nm laser irradiation on human endothelial cell proliferation. Br J Dermatol. 2003;148:334-336.
Acknowledgement
Amanda J. Kusek for compiling data of Periotest measurements and aiding in preparation of this article; Kathryn Vorwald for compiling data of Periotest measurements and aiding in the editing of this article.
Dr. Kusek is a 1984 graduate of the University of Nebraska School of Dentistry. He has been a general dentist for more than 22 years in Sioux Falls, SD. He is a Diplomate of the American Board of Oral Implantology/Implant Dentistry and the International Congress of Oral Implantologists, a Fellow of the American Academy of Implant Dentistry, and has earned Mastership in the World Clinical Laser Institute and the Academy of General Dentistry. He is adjunct professor at the University of South Dakota and lectures nationally on YSGG lasers. He can be reached at (605) 371-3443 or implantdental@midconetwork.com.
Disclosure: The author has no financial interest in Biolase or funding from the manufacturer for research studies.
