Lasers in Minimally Invasive Periodontal and Peri-Implant Therapy
Total Page:16
File Type:pdf, Size:1020Kb
Periodontology 2000, Vol. 71, 2016, 185–212 © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd Printed in Singapore. All rights reserved PERIODONTOLOGY 2000 Lasers in minimally invasive periodontal and peri-implant therapy KOJI MIZ UTANI, AKI RA AOKI , DONALD COLUZZI, RAYMOND YUKNA , CHEN-YING WANG, VERI CA PAV LIC & YUICHI IZUMI ‘Pain free’ and ‘simple procedure’ are two of the most occasionally demonstrated some effectiveness. attractive phrases to patients who are otherwise Recent evidence demonstrates that laser treatment reluctant to accept any dental treatment (138). Mini- has the potential to improve therapeutic outcomes mally invasive dental therapy (81) could satisfy the and therefore be a valuable addition to conventional demands of such patients. The procedures can be treatments (55). Currently, high-power-output lasers comfortable, although not necessarily without any are used adjunctively with scaling and root planing or pain; and be effective for disease control whilst pre- as minimally invasive surgery. Also, very-low-power- serving more healthy dental tissue. output lasers are employed for cellular stimulation Scaling and root planing is an example of a mini- and/or activation of antimicrobial agents following mally invasive procedure because it is a conservative, scaling and root planing. Both of these laser applica- cause-related therapy that attempts to eliminate etio- tions can be considered as minimally invasive logic factors from the root surface (26). Scaling and approaches to periodontal disease treatment. root planing can result in improved clinical outcomes The aim of the present review was to survey the rele- such as reduced bleeding on probing and decreased vant literature of the clinical application of lasers as periodontal pocket depth. However, some calculus minimally invasive treatment in periodontal and occasionally remains on the ‘scaled’ and ‘planed’ root implant therapy for periodontists, general practition- surface. Moreover, treatment outcomes may not ers and dental hygienists who are the primary provi- always be successful for moderate and deep peri- ders of initial treatment of these periodontal diseases odontal pockets (95). In those cases, and after further and conditions. This paper will focus on the potential evaluation, surgical procedures may be performed in therapeutic benefits of photonic energy produced by an attempt to eliminate the remaining etiological fac- laser instruments and exclude discussions of other tors, as well as to achieve regeneration of lost peri- nonlaser optical devices, such as light-emitting diodes. odontal tissue. Although periodontal surgery is not minimally invasive, it will produce better results if preceded by scaling and root planing (47). Lasers in periodontics and Clearly, if predictable treatment could be estab- peri-implant therapy lished for moderate periodontitis without surgery or with minimally invasive flapless surgery, it would pro- Laser applications for periodontal and implant therapy vide a significant benefit to many patients with have gradually expanded as a result of the increase in chronic periodontal disease, as well as to dentists published basic and clinical investigations using diode, providing their care. Thus far, conventional mechani- carbon dioxide (CO2), neodymium-doped yttrium cal therapy has not resulted in such an ideal treat- aluminium garnet (Nd:YAG), erbium-doped yttrium ment outcome, even when using power-driven aluminium garnet (Er:YAG) and erbium, chromium- devices. Moreover, antimicrobial therapy using doped: yttrium, scandium, gallium, garnet (Er,Cr: systemic or locally delivered antibiotics has only YSGG) lasers. All of these wavelengths with moderate 185 Mizutani et al. power output can be used adjunctively for initial peri- areas of inflammation by blood components and odontal therapy, not only to debride connective tissue tissue pigment. Wavelengths of 800–1,100 nm are and epithelium within periodontal pockets, but also to essentially transmitted through water, which explains inactivate bacteria that invade the periodontal tissues. their deep penetration into healthy soft tissue. As In addition, erbium lasers can ablate calculus with effi- most subgingival calculus is dark in color, to avoid ciency comparable with that of hand or ultrasonic thermal damage, care should be taken to avoid pro- instruments, preserving the root cementum under- longed contact of these types of laser on the root neath the calculus (8, 11, 46, 51, 55). The delivery of structure. Similarly, the same precautions must be laser power through a fine laser tip enables the practi- taken around osseous tissue. On the other hand, tioner to perform precise and small procedures with there is minimal to no interaction of these types of minimal damage around the treated site. Such a pre- laser with healthy dental hard tissue. This property of cise treatment modality is essential for performing diode and NdYAG lasers makes them suitable for soft- minimally invasive periodontal treatments. tissue procedures. The laser beam is conducted In contrast to the laser approaches discussed above, through an optical fiber, which is used ‘in contact’ another treatment modality has emerged, named pho- with the target tissue. However, a noncontact mode totherapy, which is better known as low-level laser may be employed when attempting any hemostasis. therapy (76). An important principle of phototherapy Although diode and Nd:YAG lasers have similar is that the power parameters employed are at a lower interactions with hard and soft tissues, they differ in dose than those used for surgery (5, 12). Low-level laser their emission mode. The Nd:YAG is a free-running therapy was often termed ‘soft laser therapy’ or ‘cold pulsed laser, with very-short-duration pulses and an laser therapy’, which created some confusion. The cur- emission cycle (ratio of ‘on’ time to total treatment rent term, photobiomodulation, more accurately time) of <1% and correspondingly very high peak describes the intended process, that is, the reduction power per pulse (in the order of 100–1,000 W). All of inflammation along with the stimulation of cell pro- diode lasers can be used in a continuous-wave mode, liferation. Another application of phototherapy is in which there is a constant emission of laser energy. antimicrobial photodynamic therapy, which aims to In addition, they can operate by producing pulses, destroy pathogens in the pocket with reactive oxygen although with larger emission cycles and significantly species produced by the combination of a low-level less peak power than the Nd:YAG laser. Thus, the visible light laser and a photosensitizer. This protocol clinician must be aware of the heat that could be pro- has attracted attention as a novel, minimally invasive duced in the target tissue by each of these types of approach for the treatment of pockets around teeth laser. and dental implants (130). For a proper understanding For initial periodontal therapy, these lasers are of the basic principles of the applications of lasers in used for inactivation of bacteria and removal of minimally invasive periodontal therapy, it is essential inflamed soft tissue from the periodontal pocket or to discuss the characteristics of each laser and their from around the implant sulcus, as well as for achiev- applications based on their particular wavelengths. ing hemostasis in acutely inflamed tissue. These pro- cedures employ relatively low average power, which are usually below that used for surgery. Characteristics of each wavelength Regarding use of the Nd:YAG laser in implant ther- in periodontal and peri-implant apy, two studies suggest that the free-running pulsed therapy Nd:YAG laser is contraindicated for treatment of tita- nium implant surfaces because the high peak power, Lasers used for periodontal and peri-implant therapy as well as the moderate reflection rate of this laser can be divided into three groups. from titanium metal, easily causes melting of the metal surface, as reported by Romanos et al. (99) and Schwarz et al. (108). However, Gonc_alves et al. (41), Lasers for soft-tissue ablation only in an in vitro study, used an Nd:YAG laser in noncon- tact mode with a longer pulse duration and demon- strated no damage to these titanium surfaces. The Diode and Nd:YAG lasers difference in the results of these studies was caused The photonic energy from diode and Nd:YAG lasers is by the irradiation parameters. Romanos et al. (99) in the near-infrared spectrum (approximately 800– employed a contact mode with a very short pulse 1,100 nm) and is readily and selectively absorbed in duration of 100 microseconds and higher average 186 Lasers in minimally invasive periodontal and peri-implant therapy power, and Giannelli et al. (39) used a pulse duration lasers can be used for soft-tissue debridement of peri- approximately 10 times longer (1 millisecond). This odontal and peri-implant diseased tissue, bacterial latter study demonstrated the ability of low-energy reduction and calculus removal in a nonsurgical Nd:YAG laser irradiation to suppress experimentally approach (106). As dental calculus has a moderate induced inflammation from contaminated implant water content, erbium lasers are indicated for its surfaces without affecting the surface morphology of removal; however, caution should be exercised not to those implant fixtures. In general, an Nd:YAG laser remove excessive cementum, which has similar must be used with caution, and attention must be hydration properties (8). given