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| REVIEW ARTICLE |
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| Year : 2017 | Volume
: 7
| Issue : 2 | Page : 41-45 |
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Lasers in implant dentistry
Litty Francis, S Babukuttan Pillai
Department of Prosthodontics, Government Dental College, Thiruvananthapuram, Kerala, India
| Date of Web Publication | 15-Feb-2018 |
Correspondence Address:
Dr. Litty Francis
A-7 Quarters, Medical College Campus, Medical College P.O, Thiruvananthapuram - 695 011, Kerala
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jdi.jdi_23_16
 Abstract | | |
Implantology has become a treatment modality with high acceptance and success rate in the past few decades. Lasers were introduced into the field of clinical dentistry in 1989 with the hope of overcoming some of the drawbacks posed by the conventional dental procedures. The two expanding aspects may be combined to provide the patients with a better clinical experience. Since its first dental application, the use of laser has increased rapidly in the last couple of decades. Their use in implant dentistry has seen an upsurge in the past years. At present, wide varieties of procedures are carried out using lasers. Laser can be classified based on the wavelengths and tissue on which it acts. All available dental laser wavelengths cannot be used in every dental implant situation. The dentist must fully understand the characteristics, merits and demerits, and applicability of the available lasers. The aim of this article is to review the applications of lasers in implant dentistry. Keywords: Dental implant, laser, peri-implantitis, photosterilization
How to cite this article:
Francis L, Pillai S B. Lasers in implant dentistry. J Dent Implant 2017;7:41-5 |
| Introduction | |  |
Light amplification by stimulated emission of radiation
A device that transforms light of various frequencies into an intense, small, and nearly nondivergent beam of monochromatic radiation within the visible range.
Lasers have been used for performing a variety of procedures, both in the medical and dental fields since its introduction by Maiman in 1960.[1],[2],[3] Drs. William and Terry Myers used a modified opthlamic Neodynium: Yttrium Aluminum Garnet (Nd: YAG) laser for dental use in 1989.[4] Lasers can be classified as soft tissue lasers and hard tissue lasers based on the tissue interaction. The soft tissue lasers include carbon dioxide (CO2), Nd: YAG, diode, argon, and holmium wavelengths whereas Erbium: YAG (Er: YAG) and Er: Yttrium scandium-gallium-garnet (Er: YSGG) are hard tissue lasers. Their use can be either an adjunct to other procedures or the main form of treatment itself. Lasers have become the treatment of choice in various clinical situations as they could be used for both hard and soft tissue without anesthesia. Both implant dentistry and lasers in dentistry have evolved so much since its introduction and combining the two sought-after treatment modalities can be beneficial for the dentist and the patient as well. The advantages of using lasers in implant dentistry include increased hemostasis, improved visibility of surgical site, minimal damage to the surrounding tissue, reduced swelling, and decreased infection due to photo sterilization effect and in turn less pain postoperatively. The use of lasers depends on the situation to which it is applied and the particular wavelength suitable for that. The dentist should have thorough knowledge regarding the specific wavelength of laser that can be used in a particular procedure and also be aware of the laser-tissue interactions that may result. Here, we discuss various applications of lasers in implant dentistry and the different wavelengths of lasers that may prove helpful.
Implant placement
Minimally invasive implant placement, using the tissue punch method, has become a popular way to place implants when proper bone height and width are available. Hard tissue lasers like Er: YAG can be used to obtain the initial breach for implant placement rather than using micromotor. A laser is used to remove the soft tissue, and the cortical plate of bone in a circular pattern to approximately 2–3 mm and rest of the osteotomy site can be prepared using a handpiece drill. Unlike conventional drills, the laser tip has less tendency to slip. This leads to quick healing time, fast integration, minimal patient discomfort, and superior bone-to-implant contact. This also eliminates the need for trauma during flap elevation and suture placement.[5] The procedure can be accomplished using a surgical guide prepared for laser placement of the implant. The advantages include a reduction in postoperative inflammation due to cleaner and sterile surgical field and better patient comfort. A study on rats by Kessler, Ramanos, and Koren [6] showed that there was significantly more bone contact and faster bone contact when comparing laser implant placement to implants placed with a conventional drill. However, the entire osteotomy site cannot be prepared using lasers.
Uncovering implants in the second stage
All wavelengths of laser can be used to Uncover Implants in stage II implant surgery with precision and ease for the practitioner and significant patient comfort by vaporizing the tissue overlying the implant till the surgical cap is reached.[7] The CO2 lasers and Er: YAG lasers are used with success while Nd: YAG laser is contraindicated as this causes temperature build up around the implants and also melting of the implant surface. This procedure is atraumatic and helps to prevent crestal bone remodeling. Care must be taken to move the laser tip in a normal manner and not to hold in one location too long to avoid any heat build-up to the implant fixture. Furthermore, care is taken to maintain an adequate amount of attached gingiva around the implants. Laser treated tissue margins do not recede after healing. The laser is tipped at a 45° angle toward the implant. The prime advantages of laser used in this procedure are hemostasis; facilitate easier visual access to the cover screw, production of a protective coagulum - an aid to healing and patient comfort during and after treatment. It also allows impression procedures to be carried out in the same appointment.
Management of peri-implantitis
Peri-implantitis is a rapidly progressive failure of osseointegration, and there is the production of bacterial toxins leading to inflammatory changes and bone loss.[8],[9] In the case of peri-implantitis, the implant surface is contaminated with soft tissue cells, bacteria and other bacterial by-products.[10] It is difficult to remove entire bacterial plaque and endotoxins by mechanical instrumentation between the implant threads. Debridement and degranulation of failing and ailing implants can be done using a laser wavelength that is noninjurious to bone. CO2 lasers, diode lasers, and Er: YAG were shown to be able to effectively remove plaque and calculus on implant abutments without injuring their surfaces.[11] Nd: YAG lasers even with their excellent sterilization qualities are contraindicated for use in the treatment of peri-implantitis as they cause an increase in the surface temperature and also changes of the implant surface. Kreisler et al.[12] performed a study on various wavelengths including Nd: YAG, holmium: YAG (Ho: YAG), Er: YAG, CO2, and gallium-aluminum-arsenide (GAAlA) for implant surface decontamination. They concluded that Nd: YAG and Ho: YAG lasers are not suitable for decontamination of dental implant surfaces at any power output. With Er: YAG and CO2, the power output must be limited so as to avoid surface damage. The GAAlA laser did not cause any surface alterations.
Photosterilization of compromised dental implant after debridement is done and the bone defect is grafted subsequently. Since laser surgery is bactericidal, infected implant sites can be relieved of pathogenic bacterial load and apical granulomas. Using scanning electron microscopy, Romanos et al.[13] investigated the attachment of osteoblasts to the titanium surface after CO2 and Er: YAG laser irradiation of the implant surface on four different types of autoclaved titanium disks with machined, hydroxyapatite-coated, sandblasted, or titanium plasma-sprayed surfaces. All the implant surfaces examined were well colonized with osteoblasts. The study data showed that laser irradiation of titanium surfaces did not negatively influence osteoblast attachment and cell proliferation. Lasers can also be used to debride extraction sites for immediate placement of implants.
Implant explantation
Increased use of dental implants has been followed with an increased rate of failing implants and the need for treatment.[14] Failing implants sometimes requires surgical removal using techniques such as block resection, buccal bone ostectomy, and trephine osteotomy.[15],[16] “Failed implants” can be removed by using Er, chromium: YSGG (Er, Cr: YSGG) laser which provides a minimally invasive technique instead of conventional methods of removal. The Er, Cr: YSGG laser has been demonstrated to effectively cut bone without burning, melting or altering the calcium: phosphorus ratio of the irradiated bone.[17] The mechanism of cutting is through the laser energy being absorbed by the air-water spray which produces microexplosions on the target tissue. This hydrokinetic effect produces clean cuts without thermal damage. The decontamination effect of lasers may occur in the surrounding tissues during explantation and may promote uncomplicated tissue healing. In case selection for laser-assisted explantation, relative contraindications to surgical tooth extraction should be applied, especially patients that have a propensity for poor wound healing are immunocompromised or those that have had previous jaw radiotherapy.
Gingival retraction
The aim of gingival retraction is to atraumatically allow access for the impression material beyond the abutment margins and to create space so that the impression material is sufficiently thick so as to be tear resistant.[18] The mechanical retraction of gingival tissues using cords, which were developed for application around natural teeth, can lead to ulceration of the junctional epithelium when used around implant restorations. The forces used in cord placement may exceed peri-implant tissues' capacity resulting in laceration of the sulcular epithelium and ulceration. There is a risk of permanent recession and loss of attachment developing. The use of mechanical retraction with cords may be contraindicated around implants, except in situ ations in which patients' sulcus depths are shallow with a healthy mucosa, and a thick gingival biotype is present. The advantages of lasers in gingival retraction are excellent hemostasis (CO2 laser is safe for implants as it is reflected by metal), reduced tissue shrinkage, relatively painless procedure and sterilizes the sulcus. The use of Nd: YAG lasers are contraindicated near implant surfaces, as they absorb energy, and heat transmission to bone.[4] There is also a tendency for Nd: YAG lasers to damage the fragile subjunctional epithelium at the sulcus base around implants. Er: YAG lasers with a wavelength of 2,940 nm are reflected by metal implant surfaces and minimally penetrate the soft tissues, so they are relatively safe to use. The hemostasis achieved with the Er: YAG laser, however, is not as effective as that achieved with the CO2 laser.[19] The CO2 lasers expose implant margins by creating a trough by excision rather than by displacing soft tissue resulting in a large defect. In anterior areas where esthetics is critical, the effect can be traumatizing. Surgical wounds created by lasers heal by secondary intention, and incision lines show disorganized fibroblast alignment. This reduces tissue shrinkage through scarring, which helps preserve gingival margin heights.[19] Evidence does not support the use of destructive procedures such as surgical retraction in the implant situation.[4],[19] Peri-implant mucosa does not have the same capacity for regeneration as peridental mucosa. The correct use of lasers with appropriate wavelengths may be applicable in some, but not all, implant situations during retraction and while making impressions.
Laser micropatterning of dental implants
Laser peening, which is a form of cold working, produces a surface with refined grain structures, compressive residual stresses, and increased hardness in metallic materials.[20],[21],[22],[23] This is done using precision laser micromachining (excimers or Nd: YAG laser) on implant surface which creates a controlled surface roughness and has shown to stimulate bone growth at the surface. Laser peening can achieve more significant surface enhancement than grit blasting.[24] The experiment conducted in a study showed that micropatterns of 20 micrometer wide and 7 micrometer deep imprinted on the biomedical implant material of cpTi through high energy pulsed laser peening was successful in creating a patterned surface and also improved the material mechanical strength. The patterned area appeared to have a significantly higher cell density than that on the untreated surface of the cpTi foil.[25] Higher removal torque values for laser micropatterned implants compared to machined implants were reported in several studies.[26],[27]
Gingival contouring
Gingival contouring of the soft tissue is desired or indicated before the preparation or impression; then, a laser is the instrument of choice to accomplish this procedure. Height or shape discrepancies can be easily corrected, and the gingival contours are maintained and the field can remain dry and clean, ready for impressions. The negligible tissue shrinkage after laser therapy is an advantage. Minor surgical correction of the gingival margin can be carried out, to assist adequate implant exposure or establish the correct emergence profile. The emergence profile of a restoration is the shape of the restoration in relation to the gingival tissues. Davarpanah et al.[28] proposed the emergence profile concept in implant therapy and a three-stage approach to ensure that concept: implant stage, intermediate abutment stage, and definitive crown placement stage. The creation of a proper contoured restoration with a natural emergence profile and gingival architecture that harmonizes with the adjacent teeth is very important for esthetic and functional implant therapy.[29]
Laser welding of titanium components
One of the hallmarks of the osseointegration technique is a passive fit of the prosthesis on the implants.[30] Laser welding can be advocated in fabricating frameworks to obtain a passive fit of implant prostheses on multiple implants. This eliminates the casting procedures and the consequences of expansion-contraction occurring during casting of the framework and the subsequent nonpassivity of the framework. Bergendal and Palmqvist [31] found that there was a tendency for more fractures of artificial teeth and acrylic resin in the titanium-welded framework group. Riedy et al.[32] concluded that the laser-welded framework exhibited a more precise fit than the one-piece casting.
Computer-aided laser cured surgical template
Presurgical planning is essential to obtain esthetic and functional implants, and a variety of techniques is presently available.[33] Surgically guided placement of implants is more accurate than freehand placement.[34] Rapid prototyping techniques allow the production of physical models on the basis of virtual computational models. The rapid prototyping technologies that are currently in use are stereolithography (SLA), inkjet-based system (3 dimensional printing), selective laser sintering (SLS), and fused deposition modeling. SLA uses an ultraviolet laser to “laser cure” cross-sections of a liquid resin and is the technique which is commonly being used for the generation of computer-generated surgical guides.[35],[36],[37] SLS models are opaque, whereas SLA models are translucent.[38] Fabrication of surgical templates using SLA have been proved to benefit from high precision by several well-documented researches.[37],[39],[40],[41],[42],[43],[44]
Low-level laser therapy/phototherapy/photobiomodulation
Also known as therapeutic lasers or Soft Lasers use sub-thermal energy density in the Red wavelength (1 mW– 500 mW). Therapeutic uses include postoperative care, tissue healing, reduced edema inflammation and pain. The biostimulatory effect of low-level laser (LLL) was pioneered by Endre Mester in Budapest in the late 1960 s, who demonstrated an increase in collagen synthesis in skin wounds. LLL therapy (LLLT) is based on biostimulation of the tissues with monochromatic light. After implant surgery, 1–5j/cm 2 energy twice weekly is used for soft tissue healing. Dörtbudak et al.[45] found that the use of low-level laser therapy with a diode soft laser (690 nm) for 60 s after the placement of toluidine blue O for 1 min on the contaminated surface reduced the counts of bacteria by a minimum of 92%. However, complete elimination was not obtained. In implantology, LLLT seems to be a promising treatment to accelerate osseointegration, as demonstrated by its effects on bone repair.[46],[47] Laser therapy improves bone matrix production because of the improved vascularization and anti-inflammatory effects. The effect of LLLT on activation and increasing collagen production demonstrated by Kana et al.[48] can also lead to a better bone matrix for bone repair. Various in vitro and in vivo animal studies have shown that LLLT has got the potential of beneficial effects on the initial establishment of the implant-bone interface [49],[50] using GAAlA diode laser. Further investigations are needed as to the laser dosage for use in humans.
| Conclusion | | |
The use of lasers in implant dentistry has expanded and improved certain treatment options for clinicians who have adopted the technology. As with all dental materials and instruments, the practitioners must undergo proper training, before incorporation of laser technology in their practice. A wide variety of procedures can be performed in a painless and comfortable way using lasers. Lasers can be used for planning of implant placement, implant site preparation, second-stage surgery of submerged implants, surgery to establish the health of soft tissue surrounding the implant and decontamination of titanium implant surfaces. The laser is an extremely useful piece of equipment for the implant dentistry and is rapidly becoming an essential component of modern implant practice. In the past few years, a wide spectrum of indications in implant dentistry has been proposed for laser systems.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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