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ePaper created 2015-11-17, 15:11:47 | version 1.38.0
Scanning elec tron m ic ros c opy The extracted implants were studied under a scanning electron microscope (SEM, Quanta 200FEG,FEI,Eindhoven,Netherlands).Owingto the presence of organic components on the sur- face after explantation, the samples were fixed with a 2.5% glutaraldehyde solution (Sigma- Aldrich, St. Louis, Mo., U.S.) in phosphate- buffered saline (PBS, Sigma-Aldrich, St. Louis, Mo., U.S.) for 8h. The samples were then dehy- drated by sequential immersion in serial diluted solutionsof0,10,30,50,70,90and100%v/vof ethanolinwater.Dehydratedsampleswerethen air-dried,carbon-coatedinasamplepreparation chamber with a sputtering system (Gatan Alto 1000E, Gatan, Abingdon, UK) and examined by SEM. Images were taken at 20 kV acceleration voltage. The SEM-attached energy-dispersive X-ray unit served to analyze the elemental com- positionofthesurfaceremnants. Results Seven patientswith nine dental implants failed owing to periimplantitis were treated accord- ingtothepreviouslydescribedprotocol.Sixpa- tients were females and the mean age was 61 ± 4 years. All patients were nonsmokers. Six of the failed dental implants were in the maxillae. Fourofthe maxillaryimplantswere in the anterior region and all of the mandibular implantswereintheposteriorregion.Theaver- age extraction torque of the failed dental im- plants was 162 ± 41 N cm. All ofthe explanted implantswere analyzed by scanning electron microscopy. Figures 2 and 3 show representative sets of SEM images of the explanted implants. All of the implants werescannedcompletelyatseveralmagnifica- tions. The lower magnification was used to ob- tain a general image of each ofthe implants ex- tracted (Fig. 2). In these general images, traces of dental plaque can clearly be observed at the coronal parts of the implants. The area depicted over the implants (white line) corre- sponds to vertical bone defects detected be- fore implant extraction. Byincreasingthe mag- nification, details such as bacterial arrange- ments could be detected (Fig. 3). These were mainly cocci (Fig. 3: g & h) and bacilli (Fig. 3: b–f), although more sensitive techniques are needed to correctly identify the particular bac- terial taxonomy. Biofilms disrupted by dehy- dration during the preparation of the samples could also be clearly identified (Fig. 3: d). In a in Figure 3, energy-dispersive X-ray spec- troscopy(EDX) showedthe presence ofresidue of inorganic materials on the implant surface, mainly iron and chrome. These particles could come from stainless-steel surgical tools used to attempt to eliminate the plaque adhering to the surface. Fromthe image,we can clearlysee that not only did the biofilm remain on the sur- face, but these procedures also left contami- nants on the implant surface. In b in Figure 3, it can be seen how the plaque preferentially Volume 1 | Issue 1/2015 11Journal of Oral Science & Rehabilitation P eriim planti ti s: Imme di ate i mplant re place me nt Fig. 3 Fig. 3 Scanning electron micrographs showing details of the surfaces of the removed implants shown in Figure 2. In some cases, EDX was performed to determine the composition of particles found on the titanium (Ti) surfaces. Several explants showed abundant microbial colonization and biofilm formation (b–h). In some cases, attempts at decontamination could be traced back to the surface of the implants: In a, we performed EDX spot analysis of the particles found on the surface and found that they corresponded to surgical tools (stainless steel: Fe, Cr). Bacterial accumulation was preferential in the rough parts of the implant surfaces (arrows in b and g). a b c d g hf e