Perceptual Changes in the Anterior Maxilla after Placement of Endosseous Implants zy Reinhilde Jacobs, DDS, PhD;*t Chen-Han Wu, DDS, MSC;* Kitty Goossens, DDS;‘ Karen Van Loven, PhD;* Daniel van Steenberghe, MD, PhD, Dr(hc)** zyxw ~ zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA ABSTRACT zyxwvutsrqpo Background: The innervation of skin and oral mucosa plays a major physiologic role in exteroception. It is also of inter- est clinically, as illustrated by sensory changes after neurosurgical procedures. Purpose: The goal of this study was to assess the perception of mechanical stimuli applied to the anterior maxilla in denture wearers and subjects rehabilitated with osseointegrated implants compared with that in subjects with a natural dentition. Materials and Methods: Five groups of subjects were selected and tested in the maxillary region only. Test groups included patients with a complete denture, an implant-supported fixed prosthesis (full or partial), or a single-tooth replacement. Light-touch sensation and two-point discrimination were performed on the buccal side of the alveolar mucosa and vibrotactile function was determined for natural teeth, full dentures, or implant-supported prostheses. Results: For light-touch sensation, no significant differences could be found between the groups. For two-point discrim- ination, full-denture patients showed higher threshold levels than the other groups. The threshold levels for vibrotactile function were higher in both full dentures and implant-supported prostheses compared with natural dentitions. Conclusion: Natural dentitions offer superior vibrotactile function compared to any other dental status. Full dentures often show a stronger deterioration of the (vibro)tactile function compared with implant-supported prostheses. KEY WORDS: endosseous implants, oral, sensory changes, tactile function, vibrotactile function ral function is largely dependent on sensory 0 inputs. Forces applied to a tooth are transmitted to the periodontal ligament. There, the periodontal mechanoreceptors are sensitive to the direction and ramp of force application and belong to the Ruffini type of mechanoreceptors.’y2The lack of the periodon- tal ligament around implants leads to a more crude peripheral input.3 Numerous investigations on the neu- rophysiologic aspects of oral implants have extended knowledge with regard to “osse~perception.”~ Patients rehabilitated with bone-anchored prostheses seem to function well even in the absence of any denti- tion. This observation led to the assumption that some *Laboratory of Oral Physiology, Department of Periodontology, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Catholic University Leuven, Leuven, Belgium; tPostdoctoral researcher of the FWO-Vlaanderen; ‘Holder of the P-I Branemark chair in osseointegration. Reprint requests: Reinhilde Jacobs, DDS, PhD, Department of Periodontology, Faculty of Medicine, Catholic University Leuven, Kapucijnenvoer 7, 3000 Leuven, Belgium; e-mail: Reinhilde.Jacobs@ med.kuleuven.ac.be zyxwvutsrqpo 0 2001 BC Decker Inc osseoperception exists conveyed by neural receptors in the immediate vicinity of endosseous implants. Changes of receptors after tooth extraction in the cat have been observed, and those that remained could still be trig- ge~-ed.~ It has also been proven that some nerve fibers regenerate after installation of implants in the jawbone of the dog. The nerve fibers histologically identified around the bone-to-implant interface probably originated from the periodontal ligament around the preceding tooth. The fibers suffered from injury by extraction and implan- tation but afterward re-innervated the peri-implant area.6 Evaluating the osseoperception phenomenon is primarily based on the assessment of tactile f ~ n c t i o n . ~ This information may lead to a better understanding of the physiologic integration of osseointegrated implants in the human body. Oral function in patients with an implant-sup- ported prosthesis has been assessed through the evalua- tion of chewing forces, bite forces, speech, and stereo- gnosis abilit~.~)~>’-’~ In the present study, the perception of mechanical stimuli applied in the anterior maxilla was determined for denture wearers and for subjects 148