Written by Eric Bornstein, DMD Saturday, 31 May 2003 19:00
As dentistry propels further into the 21st century, there are many innovative technologies currently available to the implant surgeon that can substantially lessen the trauma, pain, and potential pitfalls of traditional dental implant surgery. Three of the largest complications of traditional dental implant surgery are the following: (1) infection at the time of surgical placement, (2) incorrect implant placement resulting in nerve damage or prosthetic difficulty; and (3) suture opening in the first 7 days after the procedure, resulting in bacterial infiltration into the surgical site.
This article presents a protocol procedure designed to complete dental implant surgery without a traditional incision, without sutures, and with greatly minimized postoperative trauma and bacterial infiltration into the surgical site. This procedure combines and applies 3 innovative technologies to accomplish this goal: a complex motion tomography craniofacial imaging system, an Er:YAG dental laser, and a superpulsed CO2 dental laser. Their use is as follows:
(1) Complex motion tomography is used to image the prospective implant site in 3 dimensions with true x-ray films (not CAT scans).
(2) An Er:YAG laser is used to penetrate the gingiva in a thermal mechanical ablation of the oral mucosa at the osteotomy site.
(3) A superpulsed CO2 laser is used to cauterize the gingiva around the implant and form a seal after it is placed, if necessary.
For the purposes of this application, this combination of technologies and procedures is coined minimally invasive laser-assisted dental implant surgery, or MILADIS.
COMPLEX MOTION TOMOGRAPHIC IMAGING
Much of the success of any dental implant procedure depends on the quality of—and diagnostic information gleaned from—the preoperative imaging. In May 2000, the American Academy of Oral and Maxillofacial Radiology issued a position paper for preoperative assessment of any dental implant site. In this paper, the recommendations stated the following:
•Imaging information from panoramic, cephalometric, and intraoral films alone is inadequate to evaluate the bony architecture of any potential implant site completely.
•Evaluation of any potential implant site should include cross-sectional imaging orthogonal to the site of interest.
•This diagnostic information is best acquired with the most cost-effective and lowest radiation risk available today, which is complex motion tomography.1
Er:YAG LASER ABLATION OF MUCOSA
The Er:YAG laser is a solid-state laser that produces a beam at 2.94 µm in the mid-infrared portion of the electromagnetic spectrum. At this wavelength, the Er:YAG has the highest coefficient of absorption for water in the mid-infrared range, and correspondingly, the lowest depth of tissue penetration.2
To effectively cut or ablate human mucosa, the laser targets the chromophore of water selectively instead of the extracellular matrix of collagen and produces an instantaneous vaporization of the water to a depth of about 4 µm/pulse (four 1000ths of a millimeter) in front of the beam.3 This vaporization of water creates a volumetric expansion within the confined extracellular matrix of tissue, leading to a controlled, thermally driven mechanical fracturing of the extracellular collagen matrix and of the target tissue without causing significant thermal damage or charring.3
The above rationale is the basis for the laser-tissue interaction, with the Er:YAG optical energy being converted to local thermal energy in the target chromophore of water. The result of this interaction is a thermally driven, instantaneous controlled tissue degradation or ablation with an explosive ejection of the degraded cellular components and heated vaporous material.4,5 Also, during the Er:YAG tissue interaction, the bacteria in the path of the beam are completely destroyed because the water within their cells undergoes the same instantaneous phase change (liquid to super-hot steam) as the water in the tissue matrix being ablated.6,7 The vitality of the surrounding tissue is not harmed, and the laser tissue interaction is generally confined to 10 µm from the tissue beam interface.
SUPERPULSED CO2 HEMOSTASIS AND CAUTERIZATION
The superpulsed CO2 laser is a gas laser that produces a beam at 10.6 µm in the far infrared portion of the electromagnetic spectrum. At this wavelength, the superpulsed CO2 has the highest coefficient of absorption for water in the far-infrared range and correspondingly has a penetration depth of about 50 µm with a greater thermal interaction and diffusion than the Er:YAG.2 The superpulsed CO2 is an excellent laser for hemostasis and coagulation as opposed to the Er:YAG, which is used for cutting and thermal mechanical ablation without significant thermal diffusion to surrounding tissues.7 The superpulsed CO2 laser is also a very effective tool for bacterial destruction in the path of the beam.8
TRADITIONAL DENTAL IMPLANT SURGERY
The use of dental implants to provide prosthetic support has many advantages, including saving existing teeth, negating the need for soft tissue-borne dentures, and augmenting dental form and function for the patient. Dental implants must be surgically placed in either the maxilla or mandible of an individual and allowed to osseointegrate in the bone before loading or building of a prosthesis can take place. Correctly placed implants, with successful healing, will return a patient to oral health and solve major dental problems in the modern world.9
Traditional dental implant surgery is the science of taking a root form endosteal implant and placing it at the correct angulation in the proper location in either the maxilla or mandible. The trauma to the oral mucosa and bone should be kept to a minimum at all times during the surgery, and every attempt should be made to keep the surgical site free of bacterial infiltration. Since it is impossible to achieve a sterile environment in the oral cavity, every attempt should be made to reduce bacterial infiltration into the surgical osteotomy site.
To achieve dental implant placement using a traditional approach, the protocol by itself invites massive bacterial infiltration into the surgical area and usually requires a second surgery after osseointegration. The basic steps of traditional dental implant surgery are as follows:
(1) A generous incision completely through the mucosa and periosteum is made with a minimum of 5 mm extra distance mesial and distal to the site of implant placement for flap design.
(2) A full-thickness mucoperiosteal flap is reflected to expose the ridge of the jaw where the implant will be placed.
(3) A series of drills with internal and external irrigation with surgical saline is used to produce an osteotomy of corresponding size to the dental implant being placed.
(4) Once the implant is placed, the flapped tissues are reapproximated and sutured over the top of the implant to allow healing to take place.
If the procedure is successful, a 4- to 6-month healing (osseointegration) period is observed before a second stage or “uncovering” surgery is performed.10
MILADIS employs a different technique than the above traditional protocol and was created to solve some of the inherent problems associated with traditional dental implant surgery. The potential problems that are prevented and corrected with MILADIS include the following:
•There is no incision made or mucoperiosteal flap reflected. This greatly reduces the bacterial infiltration at the surgical visit.
•Because there is no mucoperiosteal flap raised, the surgical trauma, postoperative pain, and postoperative complications are minimized.
•Sutures are not necessary, since there is no incision to close.
•A suture removal visit is eliminated.
•Second-stage surgery is eliminated, since there is no mucoperiosteal flap sutured over the implant site.
•The potential anatomical danger issues are eliminated, since the practitioner is following a 3-dimensional complex motion tomogram of the site with a surgical stent during the procedure.
|Figure 1. Sagittal view of old Core-Vent implant (Core-Vent Corp) and prospective new implant site.||Figure 2. Cross-sectional tomogram of old Core-Vent implant. (This view would be impossible with a CT scan.)|
|Figure 3. Cross-sectional tomogram 10 mm distal to the old implant, to image prospective new implant site.||Figure 4. Sagittal view of finished procedure with MILADIS after using information gleaned from tomographic images.|
|Figures 5 through 7. Starting the procedure without conventional incisions and flaps using an Er:YAG laser.|
MILADIS starts with taking a complex motion tomogram (CommCAT, Imaging Sciences International) of the potential implant site (Figures 1 through 4). This will produce a simple-to-read, 3-dimensional x-ray of the area to guide the implant placement. Second, after local anesthesia, the Er:YAG laser (OpusDuo, OpusDent USA) is used to make a hole 3 to 5 mm in diameter through mucosa to the periosteum. To accomplish this task, a 1000-µm contact sapphire tip is used at a fluence of 600 mJ at 12 Hz with heavy water spray (Figures 5 through 7).
With this technique, there are no incisions or raising of mucoperiosteal flaps to begin the procedure, and this greatly reduces surgical trauma and bacterial introduction into the surgical site. With careful technique and execution, the practitioner need not worry about thermally damaging the cortical bone inferior to the laser contact tip.
Li et al11 and Charlton et al12 found only mild thermal interactions with a lack of carbonization in actual bone-cutting experiments with an Er:YAG laser.
|Figures 8 through 10. Creating osteotomies with internally irrigated drills and placing implants. (TwistMax HA-coated implants, Centerpulse.)|
Once the initial hole in the gingiva is created, the same series of burs with internal and external surgical saline irrigation that are used for traditional implant surgery are used in this procedure, creating the implant osteotomy through the small hole created with the Er:YAG laser. This is accomplished after careful study of the available tomogram for available bony architecture and potential implant angulation (Figures 8 through 10).
|Figures 11 and 12. Superpulsed CO2 coagulation around a newly placed implant.|
After the implant is placed, if there is excessive bleeding, the superpulsed CO2 laser (OpusDuo, OpusDent USA) is used to cauterize and seal the tissue around the coronal aspect of the implant-mucosa interface. Depending on the thickness of the mucosa, 1 mm of the implant screw cap can be left exposed to the oral environment, or with thick mucosa, a low-profile healing cap can be placed. If the superpulsed CO2 laser is used, this second laser stops the bleeding if necessary, negates the need for sutures and eliminates most of the remaining bacteria at the surgical site (Figures 11 and 12).
|Figures 13 and 14. Placement of immediate abutments and provisional restorations.|
With the MILADIS protocol, many times in the anterior region abutments can be placed immediately. This will allow the practitioner to provide patients immediate form and function in selected cases with well-made provisional restorations (Figures 13 and 14). As long as the provisionals are out of occlusion and the patient is careful for the first 60 to 90 days of the healing stage, many treatment plans can avoid the need for a “flipper provisional” and produce immediate patient satisfaction.
1. Tyndall D, Brooks S. Selection criteria for dental implant site imaging: a position paper of the American Academy of Oral and Maxillofacial Radiology. Oral Surg Oral Med Oral Pathol. 2000;89:630-637.
2. Lanigan SW. Lasers in Dermatology. London, England: Springer Verlag; 2002:57-79.
3. Venugopalan V. Pulsed laser ablation of tissue: surface vaporization or thermal explosion? Proc Soc Photo-Opt Instrum Eng. 1995;2391:184-189.
4. Walsh JT Jr, Flotte TJ, Deutsch TF. Er:YAG laser ablation of tissue: effect of pulse duration and tissue type on thermal damage. Lasers Surg Med. 1989;9:314-326.
5. Walsh JT Jr, Deutsch TF. Er:YAG ablation of tissue: measurement of ablation rates. Lasers Surg Med. 1989;9:327-337.
6. Ando Y, Aoki A, Watanabe H, et al: Bactericidal effect of erbium YAG laser on periodontopathic bacteria. Lasers Surg Med. 1996;19:190-200.
7. Clayman L, Kuo P. Lasers in Maxillofacial Surgery and Dentistry. New York, NY: Thieme Medical Pub; 1997:19-28.
8. Watson IA, Ward GD, Wang RK, et al. Comparative bactericidal activities of lasers operating at seven different wavelengths. J Biomedical Optics. 1996;1:466-472.
9. Misch C. Contemporary Implant Dentistry. 2nd ed. St. Louis, Mo: Mosby; 1999:3-12.
10. Peterson LJ. Contemporary Oral and Maxillofacial Surgery. 3rd ed. St. Louis, Mo: Mosby-Year Book; 1997:378-384.
11. Li ZZ, Reinisch L, Van de Merwe WP. Bone ablation with Er:YAG and CO2 laser: study of thermal and acoustic effects. Lasers Surg Med. 1992;12:79-85.
12. Charlton A, Dickinson M, King T. Er:YAG and Ho:YAG laser ablation of bone. Lasers Med Sci. 1990;5:365-373.
Disclosure: Dr. Bornstein is a consultant with OpusDent USA concerning matters of photobiology and laser tissue thermodynamics. He occasionally lectures for the company for a fee.
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