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A New Method to Harvest Ramus Bone Using the Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet Laser
J Oral Maxillofac Surg 63:879-882, 2005
A New Method to Harvest Ramus Bone Using the Erbium, Chromium:YttriumScandium-Gallium-Garnet Laser Cameron Y.S. Lee, DMD, MD* carbon dioxide, neodimium-doped:yttrium, aluminum and garnet and erbium-doped:yttrium aluminum, and garnet laser. Some of the advantages of laser use include the following: rapid healing, reduced postoperative pain and edema, reduced tissue trauma, increased infection control, and sterilization of the surgical field during use.11 One of the most popular lasers in oral and maxillofacial surgery is the CO2 laser (10,600-nm wavelength), which is used extensively in soft tissue surgery. The CO2 laser is highly absorbed by soft tissues due to the high water content. However, it is unsuitable for hard tissues such as enamel, dentin, and bone due to its high thermal absorption, which can damage the pulps of the teeth and necrose the bone.12,13 In vitro experiments with this laser on hard tissue showed a triple–thermal layer injury pattern. There was a well-demarcated region of charring, thermal osseous necrosis, and tissue coagulation.13 Recently, erbium lasers have proved to be the most effective laser for hard tissue procedures.14 Erbium lasers have shown the capability to ablate hard tissues without thermal injury during the ablation of enamel, cementum, and bone, as the energy is well absorbed by water and hydroxyapatite.15,16
Autogenous, monocortical block grafts are used extensively in alveolar ridge augmentation prior to implant placement. The main indication is either a defect or atrophy in the anteroposterior or buccolingual dimension, which will prevent implant placement. Donor sites available for implant reconstruction have been described in the literature. Extraoral donor sites such as the ilium,1 calvaria,2,3 clavicle,4 and scapula5 require hospitalization and are not without potential morbidity. The tibia is not recommended, as only cancellous bone is available in satisfactory amounts for grafting procedures.6 Intraoral ramus grafts from the mandible have also been used and should be the primary harvest site when possible. Advantages are reduced in-office operative and anesthesia time, low morbidity, and ease of surgical access, which can be accomplished under local anesthesia or intravenous sedation. For the young patient who has not had the mandibular third molars removed, harvesting of ramus grafts with simultaneous removal of the third molar should also be considered, as only one surgical procedure is required. The armamentarium to harvest bone from the ramus of the mandible is usually a fissure bur in a high-speed handpiece or oscillating saw. The purpose of this article is to introduce a new alternative method to harvest ramus bone from the mandible using the latest generation laser, the erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser. The acronym LASER stands for light amplification by stimulated emission of radiation. Since Theodore Maiman7 developed the ruby laser in 1960, lasers have been used widely in medicine and surgery. In 1964, Stern et al,8 Taylor,9 and Goldman et al10 first reported on the use of the ruby laser in dentistry. Since then, numerous studies were carried out on other types of lasers for use in dentistry, such as the argon,
Laser Device The laser used in the present study is the Er,Cr: YSGG laser (Biolase Technology, Inc, San Clemente, CA), which produces energy at a wavelength of 2,780 nm, which is well absorbed by water, and a pulsed duration of 140 microseconds with a repetition rate of 20 Hz. Power output is set at a maximum 6 W, yielding an energy density of 68.2 J/cm2. The laser device uses a pulsed energy source that is delivered through a fiberoptic delivery system connected to a straight handpiece with a end cutting sapphire tip that has a diameter of 750 m. During the surgical procedure, the sapphire tip is positioned 1 to 2 mm from the target tissue and is bathed by an air-water spray mist to avoid tissue carbonization. The mechanism of cutting of hard tissues is accomplished by an interaction of the laser energy with the water spray, which has been termed a “hydrokinetic effect.” During ablation of the target tissue, laser energy is ab-
*Private Practice, Aiea, HI. Address correspondence and reprint requests to Dr Lee: 98-1247 Kaahumanu Street, Suite 314, Aiea, HI 96701; e-mail: CLee555294@ aol.com © 2005 American Association of Oral and Maxillofacial Surgeons
0278-2391/05/6306-0029$30.00/0 doi:10.1016/j.joms.2005.02.028
879
880
RAMUS BONE HARVEST WITH ER,CR:YSGG LASER
sorbed by the water mist, which produces violent microexplosions on the target tissue, which causes a mechanical disintegration of calcified hard tissues such as enamel, cementum, and bone, resulting in clean cuts without causing thermal damage.17
Surgical Technique Bone was harvested from the right ascending ramus and buccal cortical plate of the mandible. If the patient was between the ages of 15 and 25 and the third molars were still present, the third molars were simultaneously extracted. In previous unpublished work, we compared the surgical technique and postoperative results of laser use and use of a conventional fissure bur in a high-speed handpiece to remove the mandibular third molars operating at 70,000 RPM. The surgical procedure in each patient was accomplished under local anesthesia. Bilateral inferior alveolar nerve blocks were administered using lidocaine 2% with 1:100,000 epinephrine. To determine the size and shape of the block graft, the recipient site is prepared for grafting before harvesting of the donor bone. Access to the ascending ramus is accomplished using an envelope flap as described by Misch.18,19 The soft tissue incision begins distal to the second molar in the buccal vestibule along the external oblique ridge and extends laterally to the retromolar pad. If needed, the incision can be extended superiorly toward the coronoid process until the temporalis tendon is visualized. From the distal aspect of the second molar, the incision is extended to the first molar. The soft tissue flap is then reflected off of the buccal cortical plate and isolated out of the surgical field with retraction sutures. A notched ramus retractor can be used to further improve surgical access. The superior horizontal laser osteotomy is started along the ascending ramus and buccal cortical plate. If the size of the graft is longer than 20 mm, the osteotomy can be extended toward the coronoid process. Posterior and anterior vertical osteotomies are then completed (Fig 1). The length of the vertical osteotomies depends on the size of the graft and care must be taken not to injure the inferior alveolar neurovascular bundle. Laser use is entirely different compared with the use of a side-cutting fissure bur in a high-speed handpiece. Tactile sensation will permit the surgeon to complete the osteotomy when using a fissure bur in a high-speed handpiece. During laser use, there is no tactile sensation as the laser is an end-cutting, noncontact surgical instrument. The sapphire tip does not contact bone and will ablate osseous tissue only if the hand is moved very slowly. With steady continuous hand movement, as in use of a high-speed handpiece, the laser will not ablate osseous tissue.
FIGURE 1. Outline of osteotomy to harvest bone from the ramus and buccal cortical plate of the mandible on a surgical model. No inferior osteotomy is required as the monocortical block graft will greenstick fracture off of the mandible using elevators or osteotomes. Cameron Y.S. Lee. Ramus Bone Harvest with Er,Cr:YSGG Laser. J Oral Maxillofac Surg 2005.
Once the outline of the osteotomy is into cancellous bone, the osteotomy is completed with a fissure bur or a thin curved osteotome with a mallet. To remove the graft from the mandible, a small straight elevator is used in a controlled manner. A inferior horizontal osteotomy is not necessary, as the block graft will greenstick fracture off from the body of the mandible. After the graft is procured from the mandible, the impacted third molar can be removed. The overlying bone can be lased with the laser to gain access to the impacted molar. The impacted tooth is then sectioned into 2 fragments using the laser, but to decrease time, it is recommended that the tooth be sectioned with the fissure bur in a high-speed handpiece.
Results Twenty-seven ramus/buccal cortical plate grafts were harvested using the Er,Cr:YSGG laser in 21 patients. Of the 21 patients, 6 underwent bilateral procedures to obtain 2 monocortical grafts due to extensive atrophy in the planned areas of implant placement. Of the 21 patients, 4 had the bilateral mandibular third molars removed at the time of grafting. The average dimension of bone that was harvested using the laser was 20 ⫻ 15 ⫻ 3 mm. Postoperatively, all patients did report edema and pain 24 to 48 hours after surgery. The 4 patients who had the third molars removed reported that pain and swelling were greater on the left side, where the contralateral third molar was removed. Postoperative pain was managed with oral narcotic analgesics or nonsteroidal anti-inflammatory medications. Sixteen of the 27 participants reported that nonsteroidal antiinflammatory medication was sufficient to manage the
CAMERON Y.S. LEE
881
postoperative pain by the third day after surgery. Of the 4 patients who had the third molars removed, 3 reported that they relied more on narcotic medication to control the discomfort on the left side where the fissure bur was used (average, 4.5 days). All participants agreed that the “popcorn-popping sound” during laser use was not intimidating compared with the characteristic high-pitched sound of the surgical handpiece.
Histologic Findings Of the 27 grafts harvested, 11 specimens were obtained and fixed in 10% neutral buffered formalin and then decalcified in 5% aqueous trichloracetic acid. The bone specimens were then processed in paraffin blocks and 5-m sections were prepared. All specimens were stained with hematoxylin and eosin stain and viewed under a Zeiss photomicroscope. The histologic findings revealed vital lamellar bone, especially at the lased margins. There was no microscopic evidence of inflammation or osteoclastic activity.
Discussion Historically, lasers were used in dentistry to remove dental caries and as a substitute for mechanical cutting with the air-turbine, high-speed handpiece to ablate teeth and bone using the argon, carbon dioxide (CO2), and neodymium-doped:yttrium-aluminum-garnet (Nd:YAG) lasers.20,21 However, they required high-energy densities to vaporize hard tissues, which resulted in pulpal damage, melting, cracking, and charring of the tooth in the surgical field.21–23 The latest generation of erbium laser has shown the ability to ablate teeth and bone without damaging the pulp or necrosing the bone.14 –16 Multiple studies24 –29 have
FIGURE 2. Viable cortical bone with osteocytes in lacunae (original magnification ⫻400). Cameron Y.S. Lee. Ramus Bone Harvest with Er,Cr:YSGG Laser. J Oral Maxillofac Surg 2005.
FIGURE 3. (A) Monocortical block grafts harvested using the Er,Cr: YSGG laser stabilized to the mandible using rigid fixation screws. (B) Implants placed in reconstructed mandible. Cameron Y.S. Lee. Ramus Bone Harvest with Er,Cr:YSGG Laser. J Oral Maxillofac Surg 2005.
shown that with underwater spray and good laser technique, thermal damage to hard tissues can be avoided (Fig 2). The disadvantage of erbium lasers is the prolonged operational time to complete the various dental procedures and the inability to provide satisfactory soft tissue hemostasis. To remove the impacted third molar using the laser, it took twice as long compared with using a fissure bur in a highspeed handpiece (20 versus 10 minutes). To harvest a monocortical block of bone with the laser, it took approximately 30 minutes from soft tissue incision to closure. Harvesting of bone using a fissure bur in a surgical handpiece took less than 15 minutes. Therefore, the surgeon should allow for additional time when using the laser. The majority of patients agreed that the amount of postoperative pain and edema that they experienced with laser use was better than expected, with most relying on nonsteroidal anti-inflammatory medication after 3 days. Histologic evaluation of all 11 specimens showed vital lamellar bone at the lased margins. We did not experience any graft failures due to infection or failure to remodel (Fig 3). Despite the increased
882 operational time to complete the surgical procedures, use of the Er,Cr:YSGG laser holds promise as an alternative method to the high-speed surgical handpiece in osseous surgery.
References 1. Keller EE, vanRoekel NB, Desjardins RP, et al: Prosthetic-surgical reconstruction of the severely resorbed maxilla with iliac bone grafting and tissue-integrated prostheses. Int J Oral Maxillofac Implants 2:155, 1987 2. Cain JR, Mitchell DL, Markowitz NR, et al: Prosthodontic restoration with dental implants and an intraoral cranial bone onlay graft: A case report. Int J Oral Maxillofac Implants 8:98, 1993 3. Donovan MG, Dickerson NC, Hanson LJ, et al: Maxillary and mandibular reconstruction using calvarial bone grafts and Branemark implants: A preliminary report. J Oral Maxillofac Surg 52:588, 1994 4. Listrom RD, Symington JM: Osseointegrated dental implants in conjunction with bone grafts. Int J Oral Maxillofac Implants 17:116, 1988 5. Buchbinder D, Urken ML, Vickery C, et al: Functional mandibular reconstruction of patients with oral cancer. Oral Surg Oral Med Oral Pathol 68:499, 1989 6. Lee CYSL: An in-office technique for harvesting tibial bone: Outcomes in 8 patients. Oral Implantol 29:181, 2003 7. Maiman TH: Stimulated optical radiation in ruby lasers. Nature 187:494, 1960 8. Stern E, Sognnaes RF, Goodman NF: Laser effects on in vitro enamel permeability and solubility. J Am Dent Assoc 73:838, 1966 9. Taylor R, Shklar G, Roeber F: The effects of laser radiation on teeth, dental pulp, and oral mucosa of experimental animals. Oral Surg Oral Med Oral Pathol 19:786, 1965 10. Goldman L, Hornby P, Meyer R, et al: Impact of the laser on dental caries. Nature 203:417, 1964 11. Spencer P, Cobb CM, Wieliczka DM, et al: Change in temperature of subjacent bone during soft tissue laser ablation. J Periodontol 69:1278, 1998 12. Gaspar L, Szabo G: Removal of benign oral tumors and tumor like lesions by CO2 laser application. Lasers Surg Med 9:33, 1989 13. Williams TM, Cobb CM, Rapley JW, et al: Histologic evaluation of alveolar bone following CO2 laser removal of connective
RAMUS BONE HARVEST WITH ER,CR:YSGG LASER
14. 15.
16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29.
tissue from periodontal affects. Int J Periodont Restorative Dent 15:497, 1995 Krause LS, Cobb CM, Rapley JW, et al: Laser irradiation of bone. An in-vitro study concerning the effects of the CO2 laser on oral mucosa and subjacent tissue. J Periodontol 68:872, 1997 Goodies HE, Pashley D, Stabholz A: Pulpal effects of thermal and mechanical irritants, in Hargreaves KM, Goodies HE (eds): Seltzer’s and Bender’s Dental Pulp. Chicago, IL, Quintessence, 2002, pp 371-388 Bornstein ES: Why wavelength and delivery systems are the most important factors in using a dental hard tissue laser: A literature review. Compend Contin Educ Dent 4:837, 2003 Rizoiu I, Kohanghadosh F, Kimmel AI, et al: Pulpal thermal response to an ErCr:USGG pulsed laser hydrokinetic system. Oral Surg Oral Med Oral Pathol Radiol Endod 86:220, 1998 Misch CM: Ridge augmentation using mandibular ramus bone grafts for the placement of dental implants. Pract Periodont Anesth Dent 8:127, 1996 Misch CM: The use of ramus grafts for ridge augmentation. Dent Implant Update 9:41, 1998 Melcer J, Chaumette MT, Melcer F, et al: Treatment of dental decay by CO2 laser beam: Preliminary results. Lasers Surg Med 4:311, 1984 Wigdor HA, Abt E, Ashrafi S, et al: The effects of lasers on dental hard tissues. JADA 124:65, 1993 White JM, Fagan MC, Goodis HE: Intra-pulpal temperatures during pulsed Nd:YAG laser treatment of dentin in-vitro. J Periodontol 65:255, 1999 Tokita Y, Sunakawa M, Suda H: Pulsed Nd:YAG laser irradiation of the tooth pulp in the cat: Effect of spot lasing. Lasers Surg Med 26:398, 2000 Paghdiwala AF: Er:YAG laser hard tissue effects, in Moretti M, Westford MA (eds): Lasers in Dentistry. Penn Well Pub Co, 1991, pp 63–75 Burkes EJ, Hoke J, Gomes E, et al: Wet versus dry enamel ablation by Er:YAG laser. J Prosthet Dent 67:847, 1992 Keller U, Hibst R: Experimental studies of the application of the Er:YAG laser on dental hard substances: II. Light microscopic and SEM investigations. Lasers Surg Med 9:345, 1989 Aoki A, Ishikawa T, Yamada M, et al: Comparison between Er:YAG laser and conventional technique for root caries treatment in-vitro. J Dent Res 77:1404, 1998 Hossain M, Nakamura, Y, Yamada Y, et al: Effects of Er,Cr: YSGG laser irradiation in human enamel and dentin: ablation and morphological studies. J Clin Laser Med Surg 17:155, 1999 Yu DG, Kimura Y, Kinoshita JI, et al: Morphological and atomic analytical studies on enamel and dentin irradiated by an Er,Cr: YSGG laser. J Clin Laser Med Surg 18:139, 2000
A New Method to Harvest Ramus Bone Using the Erbium, Chromium:YttriumScandium-Gallium-Garnet Laser Cameron Y.S. Lee, DMD, MD* carbon dioxide, neodimium-doped:yttrium, aluminum and garnet and erbium-doped:yttrium aluminum, and garnet laser. Some of the advantages of laser use include the following: rapid healing, reduced postoperative pain and edema, reduced tissue trauma, increased infection control, and sterilization of the surgical field during use.11 One of the most popular lasers in oral and maxillofacial surgery is the CO2 laser (10,600-nm wavelength), which is used extensively in soft tissue surgery. The CO2 laser is highly absorbed by soft tissues due to the high water content. However, it is unsuitable for hard tissues such as enamel, dentin, and bone due to its high thermal absorption, which can damage the pulps of the teeth and necrose the bone.12,13 In vitro experiments with this laser on hard tissue showed a triple–thermal layer injury pattern. There was a well-demarcated region of charring, thermal osseous necrosis, and tissue coagulation.13 Recently, erbium lasers have proved to be the most effective laser for hard tissue procedures.14 Erbium lasers have shown the capability to ablate hard tissues without thermal injury during the ablation of enamel, cementum, and bone, as the energy is well absorbed by water and hydroxyapatite.15,16
Autogenous, monocortical block grafts are used extensively in alveolar ridge augmentation prior to implant placement. The main indication is either a defect or atrophy in the anteroposterior or buccolingual dimension, which will prevent implant placement. Donor sites available for implant reconstruction have been described in the literature. Extraoral donor sites such as the ilium,1 calvaria,2,3 clavicle,4 and scapula5 require hospitalization and are not without potential morbidity. The tibia is not recommended, as only cancellous bone is available in satisfactory amounts for grafting procedures.6 Intraoral ramus grafts from the mandible have also been used and should be the primary harvest site when possible. Advantages are reduced in-office operative and anesthesia time, low morbidity, and ease of surgical access, which can be accomplished under local anesthesia or intravenous sedation. For the young patient who has not had the mandibular third molars removed, harvesting of ramus grafts with simultaneous removal of the third molar should also be considered, as only one surgical procedure is required. The armamentarium to harvest bone from the ramus of the mandible is usually a fissure bur in a high-speed handpiece or oscillating saw. The purpose of this article is to introduce a new alternative method to harvest ramus bone from the mandible using the latest generation laser, the erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser. The acronym LASER stands for light amplification by stimulated emission of radiation. Since Theodore Maiman7 developed the ruby laser in 1960, lasers have been used widely in medicine and surgery. In 1964, Stern et al,8 Taylor,9 and Goldman et al10 first reported on the use of the ruby laser in dentistry. Since then, numerous studies were carried out on other types of lasers for use in dentistry, such as the argon,
Laser Device The laser used in the present study is the Er,Cr: YSGG laser (Biolase Technology, Inc, San Clemente, CA), which produces energy at a wavelength of 2,780 nm, which is well absorbed by water, and a pulsed duration of 140 microseconds with a repetition rate of 20 Hz. Power output is set at a maximum 6 W, yielding an energy density of 68.2 J/cm2. The laser device uses a pulsed energy source that is delivered through a fiberoptic delivery system connected to a straight handpiece with a end cutting sapphire tip that has a diameter of 750 m. During the surgical procedure, the sapphire tip is positioned 1 to 2 mm from the target tissue and is bathed by an air-water spray mist to avoid tissue carbonization. The mechanism of cutting of hard tissues is accomplished by an interaction of the laser energy with the water spray, which has been termed a “hydrokinetic effect.” During ablation of the target tissue, laser energy is ab-
*Private Practice, Aiea, HI. Address correspondence and reprint requests to Dr Lee: 98-1247 Kaahumanu Street, Suite 314, Aiea, HI 96701; e-mail: CLee555294@ aol.com © 2005 American Association of Oral and Maxillofacial Surgeons
0278-2391/05/6306-0029$30.00/0 doi:10.1016/j.joms.2005.02.028
879
880
RAMUS BONE HARVEST WITH ER,CR:YSGG LASER
sorbed by the water mist, which produces violent microexplosions on the target tissue, which causes a mechanical disintegration of calcified hard tissues such as enamel, cementum, and bone, resulting in clean cuts without causing thermal damage.17
Surgical Technique Bone was harvested from the right ascending ramus and buccal cortical plate of the mandible. If the patient was between the ages of 15 and 25 and the third molars were still present, the third molars were simultaneously extracted. In previous unpublished work, we compared the surgical technique and postoperative results of laser use and use of a conventional fissure bur in a high-speed handpiece to remove the mandibular third molars operating at 70,000 RPM. The surgical procedure in each patient was accomplished under local anesthesia. Bilateral inferior alveolar nerve blocks were administered using lidocaine 2% with 1:100,000 epinephrine. To determine the size and shape of the block graft, the recipient site is prepared for grafting before harvesting of the donor bone. Access to the ascending ramus is accomplished using an envelope flap as described by Misch.18,19 The soft tissue incision begins distal to the second molar in the buccal vestibule along the external oblique ridge and extends laterally to the retromolar pad. If needed, the incision can be extended superiorly toward the coronoid process until the temporalis tendon is visualized. From the distal aspect of the second molar, the incision is extended to the first molar. The soft tissue flap is then reflected off of the buccal cortical plate and isolated out of the surgical field with retraction sutures. A notched ramus retractor can be used to further improve surgical access. The superior horizontal laser osteotomy is started along the ascending ramus and buccal cortical plate. If the size of the graft is longer than 20 mm, the osteotomy can be extended toward the coronoid process. Posterior and anterior vertical osteotomies are then completed (Fig 1). The length of the vertical osteotomies depends on the size of the graft and care must be taken not to injure the inferior alveolar neurovascular bundle. Laser use is entirely different compared with the use of a side-cutting fissure bur in a high-speed handpiece. Tactile sensation will permit the surgeon to complete the osteotomy when using a fissure bur in a high-speed handpiece. During laser use, there is no tactile sensation as the laser is an end-cutting, noncontact surgical instrument. The sapphire tip does not contact bone and will ablate osseous tissue only if the hand is moved very slowly. With steady continuous hand movement, as in use of a high-speed handpiece, the laser will not ablate osseous tissue.
FIGURE 1. Outline of osteotomy to harvest bone from the ramus and buccal cortical plate of the mandible on a surgical model. No inferior osteotomy is required as the monocortical block graft will greenstick fracture off of the mandible using elevators or osteotomes. Cameron Y.S. Lee. Ramus Bone Harvest with Er,Cr:YSGG Laser. J Oral Maxillofac Surg 2005.
Once the outline of the osteotomy is into cancellous bone, the osteotomy is completed with a fissure bur or a thin curved osteotome with a mallet. To remove the graft from the mandible, a small straight elevator is used in a controlled manner. A inferior horizontal osteotomy is not necessary, as the block graft will greenstick fracture off from the body of the mandible. After the graft is procured from the mandible, the impacted third molar can be removed. The overlying bone can be lased with the laser to gain access to the impacted molar. The impacted tooth is then sectioned into 2 fragments using the laser, but to decrease time, it is recommended that the tooth be sectioned with the fissure bur in a high-speed handpiece.
Results Twenty-seven ramus/buccal cortical plate grafts were harvested using the Er,Cr:YSGG laser in 21 patients. Of the 21 patients, 6 underwent bilateral procedures to obtain 2 monocortical grafts due to extensive atrophy in the planned areas of implant placement. Of the 21 patients, 4 had the bilateral mandibular third molars removed at the time of grafting. The average dimension of bone that was harvested using the laser was 20 ⫻ 15 ⫻ 3 mm. Postoperatively, all patients did report edema and pain 24 to 48 hours after surgery. The 4 patients who had the third molars removed reported that pain and swelling were greater on the left side, where the contralateral third molar was removed. Postoperative pain was managed with oral narcotic analgesics or nonsteroidal anti-inflammatory medications. Sixteen of the 27 participants reported that nonsteroidal antiinflammatory medication was sufficient to manage the
CAMERON Y.S. LEE
881
postoperative pain by the third day after surgery. Of the 4 patients who had the third molars removed, 3 reported that they relied more on narcotic medication to control the discomfort on the left side where the fissure bur was used (average, 4.5 days). All participants agreed that the “popcorn-popping sound” during laser use was not intimidating compared with the characteristic high-pitched sound of the surgical handpiece.
Histologic Findings Of the 27 grafts harvested, 11 specimens were obtained and fixed in 10% neutral buffered formalin and then decalcified in 5% aqueous trichloracetic acid. The bone specimens were then processed in paraffin blocks and 5-m sections were prepared. All specimens were stained with hematoxylin and eosin stain and viewed under a Zeiss photomicroscope. The histologic findings revealed vital lamellar bone, especially at the lased margins. There was no microscopic evidence of inflammation or osteoclastic activity.
Discussion Historically, lasers were used in dentistry to remove dental caries and as a substitute for mechanical cutting with the air-turbine, high-speed handpiece to ablate teeth and bone using the argon, carbon dioxide (CO2), and neodymium-doped:yttrium-aluminum-garnet (Nd:YAG) lasers.20,21 However, they required high-energy densities to vaporize hard tissues, which resulted in pulpal damage, melting, cracking, and charring of the tooth in the surgical field.21–23 The latest generation of erbium laser has shown the ability to ablate teeth and bone without damaging the pulp or necrosing the bone.14 –16 Multiple studies24 –29 have
FIGURE 2. Viable cortical bone with osteocytes in lacunae (original magnification ⫻400). Cameron Y.S. Lee. Ramus Bone Harvest with Er,Cr:YSGG Laser. J Oral Maxillofac Surg 2005.
FIGURE 3. (A) Monocortical block grafts harvested using the Er,Cr: YSGG laser stabilized to the mandible using rigid fixation screws. (B) Implants placed in reconstructed mandible. Cameron Y.S. Lee. Ramus Bone Harvest with Er,Cr:YSGG Laser. J Oral Maxillofac Surg 2005.
shown that with underwater spray and good laser technique, thermal damage to hard tissues can be avoided (Fig 2). The disadvantage of erbium lasers is the prolonged operational time to complete the various dental procedures and the inability to provide satisfactory soft tissue hemostasis. To remove the impacted third molar using the laser, it took twice as long compared with using a fissure bur in a highspeed handpiece (20 versus 10 minutes). To harvest a monocortical block of bone with the laser, it took approximately 30 minutes from soft tissue incision to closure. Harvesting of bone using a fissure bur in a surgical handpiece took less than 15 minutes. Therefore, the surgeon should allow for additional time when using the laser. The majority of patients agreed that the amount of postoperative pain and edema that they experienced with laser use was better than expected, with most relying on nonsteroidal anti-inflammatory medication after 3 days. Histologic evaluation of all 11 specimens showed vital lamellar bone at the lased margins. We did not experience any graft failures due to infection or failure to remodel (Fig 3). Despite the increased
882 operational time to complete the surgical procedures, use of the Er,Cr:YSGG laser holds promise as an alternative method to the high-speed surgical handpiece in osseous surgery.
References 1. Keller EE, vanRoekel NB, Desjardins RP, et al: Prosthetic-surgical reconstruction of the severely resorbed maxilla with iliac bone grafting and tissue-integrated prostheses. Int J Oral Maxillofac Implants 2:155, 1987 2. Cain JR, Mitchell DL, Markowitz NR, et al: Prosthodontic restoration with dental implants and an intraoral cranial bone onlay graft: A case report. Int J Oral Maxillofac Implants 8:98, 1993 3. Donovan MG, Dickerson NC, Hanson LJ, et al: Maxillary and mandibular reconstruction using calvarial bone grafts and Branemark implants: A preliminary report. J Oral Maxillofac Surg 52:588, 1994 4. Listrom RD, Symington JM: Osseointegrated dental implants in conjunction with bone grafts. Int J Oral Maxillofac Implants 17:116, 1988 5. Buchbinder D, Urken ML, Vickery C, et al: Functional mandibular reconstruction of patients with oral cancer. Oral Surg Oral Med Oral Pathol 68:499, 1989 6. Lee CYSL: An in-office technique for harvesting tibial bone: Outcomes in 8 patients. Oral Implantol 29:181, 2003 7. Maiman TH: Stimulated optical radiation in ruby lasers. Nature 187:494, 1960 8. Stern E, Sognnaes RF, Goodman NF: Laser effects on in vitro enamel permeability and solubility. J Am Dent Assoc 73:838, 1966 9. Taylor R, Shklar G, Roeber F: The effects of laser radiation on teeth, dental pulp, and oral mucosa of experimental animals. Oral Surg Oral Med Oral Pathol 19:786, 1965 10. Goldman L, Hornby P, Meyer R, et al: Impact of the laser on dental caries. Nature 203:417, 1964 11. Spencer P, Cobb CM, Wieliczka DM, et al: Change in temperature of subjacent bone during soft tissue laser ablation. J Periodontol 69:1278, 1998 12. Gaspar L, Szabo G: Removal of benign oral tumors and tumor like lesions by CO2 laser application. Lasers Surg Med 9:33, 1989 13. Williams TM, Cobb CM, Rapley JW, et al: Histologic evaluation of alveolar bone following CO2 laser removal of connective
RAMUS BONE HARVEST WITH ER,CR:YSGG LASER
14. 15.
16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29.
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