The Effect of CO2 Laser Irradiation on Failed Implant Surfaces

The Effect of CO2 Laser Irradiation on Failed Implant Surfaces
Implant Dentistry: Volume 13(4) 2004 pp 342-351
Shibli, Jamil Awad DDS, MS, PhD*; Theodoro, Let??cia Helena DDS, MS, PhDÇƒÜ; Haypek, Patr??cia DDS, MSÇƒ?; Garcia, Valdir Gouveia DDS, MS, PhD¨?; Marcantonio, Elcio Jr. DDS, MS, PhD
Lippincott Williams & Wilkins
Abstract
The aim of this investigation was to evaluate the cleaning effect of CO2 on surface topography and composition of failed dental implant surfaces. Ten failed dental implants were retrieved from nine patients (mean age, 46.33 ¨± 5.81 years) as a result of early or late failure. The implants were divided into two parts: one side of the implant was irradiated with a CO2 laser (test side), while the other side did not receive irradiation (control side). The CO2 laser was operated at 1.2 W in a continuous wave for 40 seconds (40 J energy). The handpiece of the CO2 laser was kept at a distance of 30 mm from the implant surface, resulting in a spot area of 0.031415 cm2 (38.20 W/cm2; 1559 J/cm2) in scanning mode (cervical-apical). One unused dental implant was used as a negative control for both groups. All implant surfaces were examined by scanning electron microscopy (SEM) and energy-dispersive spectrometer x-ray (EDS) for element analysis. SEM showed that the surface of the test sides consisted of different degrees of organic residues, appearing mainly as dark stains similar to those observed on the control sides. None of the test surfaces presented alterations such as crater-like alterations, lava-like layers, or melting compared with the nonirradiated surfaces. Foreign elements such as carbon, oxygen, sodium, calcium, and aluminum were detected on both sides. These results suggest that CO2 laser irradiation does not modify the implant surface, although the cleaning effect was not satisfactory.
The use of dental implants in oral rehabilitation has gained importance in daily clinical practice. Despite these advances, dental implant failures have been reported.1,2 These failures can be classified on the basis of both chronologic (early or late) and etiologic aspects. Early implant failures have been attributed to surgical trauma, inadequate bone quality and quantity, lack of primary stability, and bacterial contamination of the recipient site.3 Late failures have been attributed to overload, peri-implant infections, or associations of both.
Recent evaluations have questioned the importance of implant surface cleanliness after peri-implantitis treatment.4-6 The aim of a cleaning procedure should be to remove the contaminated surface oxide without changing the surface topography or harming the surrounding tissues.7,8 It has been hypothesized that surface contaminants may be released from contaminated implant surfaces, enhancing and perpetuating the inflammatory response, thus altering the healing process and possibly provoking the dissolution of titanium.8-11 In addition, the alterations of this oxide layer surface may hamper reosseointegration.
The integration of titanium dental implants in alveolar bone has been partly ascribed to the biocompatibility of the surface oxide layer.12 Several authors have described the titanium oxide layer as a thin layer of 2-6 nm of TiO2 covered by a carbon-dominated contamination layer and traces of nitrogenous (N), calcium (Ca), phosphorous (P), chloride (Cl), sulfur (S), sodium (Na), and silicon (Si).11,13-19
Sterilization and cleaning/decontamination of dental implant surfaces by means of both high- and low-intensity laser therapy using CO2, Nd:YAG, Ho:YAG, Er:YAG, and GaAlAs has been used.20-25 However, heat generation at the interface between the dental implant surface and the alveolar bone during laser irradiation must be taken into consideration. Temperatures between 47¨?C and 50¨?C induce tissue damage in the bone.26 In addition, Romanos et al.24 suggest that an understanding of the characteristics of the applied laser energy to optimize therapeutic implementation of lasers in implantology to avoid complications principally as a result of heat generation resulting in lack of osseointegration.
The use of the CO2 laser has been suggested as one possible instrument for the removal of inflammatory soft tissue27 as well as for sterilization and decontamination of dental implant surfaces.20,22,28 Complementary CO2 laser irradiation may be a useful way to eliminate periodontal pathogenic bacteria from titanium surfaces.29 In an earlier study, Haypek30 evaluated the microbiologic effect of CO2 laser irradiation at a dental implant surface contaminated with Streptococcus sanguis. The author observed that using power of 0.6 W, 0.9 W, and 1.2 W for 40 s, the CO2 laser irradiation was able to kill the microorganism without an increase of temperature over 8¨?C.
Although several studies have evaluated the cleaning effect on the contaminated titanium surface in vitro 21,24,25 or in vivo using animal models,4-7 few studies evaluated the effect of laser irradiation on failed implants retrieved from human patients as a result of early or late failures.
Thus, the aim of this study was to evaluate the cleaning effect and possible oxide layer alterations on contaminated titanium surface from 10 consecutively retrieved dental implants after CO2 laser irradiation using scanning electron microscopy (SEM) and energy-dispersive x-ray spectrometry (EDS).
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