Implants with cement remnants in patients with history of periodontitis may be more likely to develop peri-implantitis, compared with patients without history of periodontal infection.

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SummaryIntroduction. Dental implant therapy has become a popular method of replacing one or more missing teeth. Osseointegrated dental implants have been studied from histological, microbiologic and biomechanical point of view, but the neurophysiologic integration of the implants and the supported prostheses has received less attention. The sensory mechanism of dental implants is qualitatively different from that of natural teeth. Psychophysiological tests are used to determine the tactile sensibility perceived with the implants and teeth.Aim of the study. The purpose of this study was to compare tactile sensibility of natural teeth and osseointegrated dental implants.Material and methods. Forty-three patients were included in the study. Natural teeth were divided into two groups: non endodontically treated teeth (NETT) and endodontically treated teeth (ETT). Load tests were done by a computer-controlled pressure sensitive device („Power Lab“ Data Acquisition System - model 4/25T, sensor - model MLT003/D; ADInstruments), specially modified for intraoral use. Pushing forces were applied parallel to the vertical axis of teeth and implants. The patient held a signal button which he/she activated as soon as touch was sensed. At this moment the computer registered passive absolute tactile threshold - measured in Newtons. The mean values of passive absolute tactile threshold for natural teeth and dental implants were calculated. Comparison of the mean values was performed by the means of t-test.Results. Passive absolute tactile threshold for osseointegrated dental implants was 2.39 N (SD=1.92), and for teeth - 0.67 N (SD=0.72), for non endodontically treated teeth it was 0.63 N (SD=0.72) and for endodontically treated teeth - 0.73 N (SD=0.69). The differences in mean values were statistically significant (p<0,0001) except for mean values of NETT vs. ETT.Conclusion. This study shows that patients with osseointegrated implants subjectively feel “touch” sensation when greater force is applied compared with natural teeth.

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Background : Gradual bone loss around the implants is an ongoing concern. More recently peri-implant mucosal tissue thickness (MTT) is considered as a contributing factor which influences bone remodelling. It has been suggested that tissue thickness thinner than 2.5 mm may contribute to more peri-implant bone loss eventually affecting implant bone stability. Measuring of MTT prior to surgery may be a predictor of the bone changes and could modify the surgical methods. Aim/Hypothesis : The aim of this radiographic retrospective study was undertaken to test the relationship of peri-implant MTT on long-term (3-5 yrs) bone changes. The null hypothesis tested that MTT influences bone stability. Materials and Methods : This retrospective radiographic study evaluated proximal peri-implant bone changes around in the maxillary premolar area. Patients were selected from "Adenta Dental Clinic" database (included if radiographs were acquired prior to surgery, 1st year after surgery, 3-5 years after surgery). Patients were divided in to two groups based on Linkevicius et. al. (2009) study. Each measurement was done three times by three experts with initials: IA, RL, AG. Peri-implant bone levels were measured at proximal sites two times: one year and 3 to 5 years after implant placement. The differences in bone thickness at proximal sites (DM, DD) and relationship between MTT and peri-implant bone stability were evaluated in both groups (Group 1 = MTT < 2.5 mm and Group 2 = MTT ≥ 2.5 mm). Additionally, patient smoking status (yes/no) and implant diameters (small implant group: 3-3.9 mm; large implant group 4-5 mm) were compared to MTT and peri-implant bone changes. Results : Total of 450 measurements of MTT and 150 measurements of proximal sites were taken in 50 patients (22 M, 28 F) with the average age of 57 years (12 patients with smoking of at least 10 cigarettes a day. Radiographs were divided into two groups: group 1-(61 measurements of proximal sites, 183 measurements of MTT); group 2-(89 measurements of proximal sites, 267 measurements of MTT). Average MTT in group 1 was 1.88 ± 0.05 mm and for group 2 was 3.12 ± 0.06 mm (P < 0.001). There were no differences between groups in 1st and 2nd follow up at proximal sites (1st follow-up mesial site: P = 0.168 and distal site P = 0.125), (2nd follow-up mesial site: P = 0.230 and distal site P = 0.325). There were no correlations with MTT and peri-implant bone changes in Group 1