Diederik Hentenaar

58 Chapter 3 When it was not possible to position the X-ray holder peri-apically in fully edentulous patients (painful to the floor of the mouth, or no position in which reproducible images could be made), panoramic images were taken. Peri-implant bone loss was measured using the DICOM software (DicomWorks 1.5). Calibration of each radiograph took place on a 3-point reference scale using the known implant length and/or diameter. Bone level differences were calculated for the mesial and distal site of the implant. The outer points of the implant connection plateau were taken as reference to which the initial bone level was present (in bone level implants). Measurement corrections were made in the presence of a smooth transgingival segment of the implant (1-stage implant systems i.e., tissue level implants). In order to calculate the inter-observer and intra- observer agreement, radiographic images of ten randomly selected implants were examined twice by the same researcher (D.H.) and once by another researcher (H.M.), both of whom were blinded regarding group allocation. Subsequently, D.H. measured all the X-ray images. Microbiological sampling A biofilm sample from the peri-implant sulcus was obtained at baseline, 3 and 12 months using sterile paper points. Before sampling supragingival plaque was mechanically removed. Samples were taken from four sites around the implant (mesiobuccal, distobuccal, mesioligual, distolingual). If a patient had more than one implant, sampling of the deepest pocket per implant took place. The samples collected from each patient were pooled in an empty vial. In dentate patients, bacterial samples were also taken from the site with the deepest probing pocket depth in each quadrant. If no deepened pockets were present, samples were taken from the mesiobuccal pockets of the teeth numbers 16, 26, 36 and 46. Outcome variables were the presence and numbers of the following putative periodontal pathogens; Aggregatibacter actinomycetemcomitans ( Aa ), Porphyromonas gingivalis (Pg ), Prevotella intermedia (Pi) , Tannerella forsythia (Tf ) , Fusobacterium nucleatum (Fn) , Parvimonas micra (Pm) , Treponema denticola (Td) , and Filifactor alocis (Fa) . Microbial samples were sent to Lab Oral Diagnostics (Houten, the Netherlands) and analysed using real time-PCR (quantitative polymerase chain reaction - qPCR). Visual Analog Scale score Immediately after the treatment all patients scored the level of pain and discomfort they had experienced during both the peri-implant therapy and periodontal cleaning using a Visual Analog Scale (VAS) ranging from 0 to 10.