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ePaper created 2016-04-05, 13:01:42 | version 1.38.0
| research 18 laser 1 2016 Smear layer removal with laser in drilled implant holes A pilot study Author: Dr Alireza Mirzaee, Iran Introduction Dental implants form a new opportunity window for individuals who have lost their teeth due to var- ious reasons such as trauma, dental caries and periodontal diseases.1, 2 According to published pa- pers, less than 8 % of dental implantation surgeries have failed.3, 4 Formation of smear layer after usage of dentistry tools or by bacterial flora surrounding the implant cavity may, however, result in implant fracture.5–7 Smear layer refers to a remainder of bone tissue after usage of dentistry tools which may challenge the success of relief, joints and penetration of ma- terials to bottom layers such as the root canal. This layer includes different materials like bone and soft tissue lesions, blood cells and microorganisms. These lesions are not limited to inter-dental or bone septum, but may penetrate to bone tubules and do not solve related negative effects.5, 8 Forma tion of this layer defects the sealing process and creates an environment for growth of microorgan- isms and bacteria to bone tissue which may de- crease the probability of deep cleansing and result in fracture of the implant.5 Therefore, it is highly required to discover safe and inexpensive methods to remove this layer. Laser is abbreviated from “Light Amplification by Stimulated Emission of Radiation” and is effec- tively used in dentistry interventions.9 Various types of lasers have different impacts on bacteria, depending on type of radiation, conditions of ra diation and bacterial density. Vercruyssen et al. conducted a study in which they applied pulsed Nd:YAG laser radiation on teeth root in in-vitro environment. The results indicated that density of E.coli and Staphylococcusaureus was significantly reduced and when the application of sodium hy- pochlorite was added to the treatment, the bacte- ricidal effect was increased.10 Meral et al. reported that Nd:YAG laser radiation exhibits various levels of lethality rates for different bacteria. As their re- sults shown, the lethality rate for Staphylococcus alpha hemolytic was higher compared to Staphy- lococcus nicira.11 In another study conducted by Lee et al. with diode laser applied on Staphylococ- cus mutans colonies with a thickness of 500 mi- crons, a lethality rate of 97.7 % was observed. With increase in thickness of the bacteria colony, the le- thality rate was reduced.12 Many types and categories of laser instru- ments are being introduced to the worlds of den- tistry and medicine, but their application and ef- fectiveness are yet to be evaluated and studied. Among these instrument, Er,Cr:YSGG laser is widely used for bone incisions and soft tissues surgeries in dentistry.13 Compared to conven- tional mechanical drills, this particular type of la- ser exhibits minimised tissue damage and does not increase the tissue temperature to intolerable ranges.14 The bactericidal effects of Er,Cr:YSGG laser is another important aspect of this type of laser. Schoop et al. observed in their research that Er,Cr:YSGG laser managed to remove the layer of bacteria from smear layer on the root.15 Miller et al. stated that this type of laser has an appro- priate impact in disinfecting the dental implant surface.16 Since this type of laser has been ac- cepted as a conventional disinfecting instrument, 12016