Perceptual changes after implants placement in the symphyseal area

Objectives: To assess potential neurosensory disturbances in patients treated by oral implants in the anterior mandible (symphyseal area). Methods: A group of 65 consecutively treated patients (range 30-84 years, X = 58; 30 females) was enrolled. All were treated by means of 3 immediately loaded implants (Brånemark Novum System®, NobelBiocareTM, Gothenburg, Sweden) at two different University Hospitals by 5 different periodontologists/oral surgeons. A questionnaire was used 8-40 months after surgery to find out about past and present neurosensory disturbances. Those patients who reported a sensory disturbance were subjected at psychological and psychophysical tests. The psychological test was the SCL-90-R® (Symptom Checklist-90-Revised) for symptom measuring, patient treatment outcomes and their degree of somatisation. Psychophysical tests included 3 neurosensory evaluations: two-point discrimination, thermal sensitivity, and light touch sensation. The staircase method of limits was applied to determine the tactile threshold. An age- and gender-matched group of patients who had undergone similar surgery in the same area served as a control. Results: The response rate for the questionnaire was 89%. One third had experienced neurosensory disturbances following implant surgery, but none were perceived as permanent and patients considered that the benefits outweigh the disadvantages experienced. Only 9 of 19 patients accepted further testing. The scores of the psychological test revealed no statistical differences between the patients who had experienced subjective complaints and the control group. These results indicate that no somatisation had occurred. Two point discrimination and thermal sensation tests were similar in both groups and revealed no sensory lesions. The light touch sensation test at the lower lip indicated a more frequent reduction of tactility for the test group (p ≤ 0,03). Conclusion: Neurosensory disturbances regularly occur in the anterior region of the mandible after implant surgery. Patients are sometimes not conscious of this postoperative loss of tactile sensitivity.