Perceptual Changes in the Peri-Implant Soft Tissues Assessed by Directional Cutaneous Kinaesthesia and Graphaesthesia: A Prospective Study Pascale Habre-Hallage, DDS, MSC;* Nada Bou Abboud-Naaman, DDS, PhD; † Herve Reychler, MD, PhD; ‡ Daniel van Steenberghe, MD, PhD, Dr(hc); § Reinhilde Jacobs, DDS, PhD ¶ ABSTRACT Background: The innervation of skin and oral mucosa plays a major physiological role in exteroception. This innervation is also clinically relevant as sensory changes occur after neurosurgical procedures. Purpose: The goal of this study was to compare the perception of mechanical stimuli applied to the buccal mucosa in the vicinity of osseointegrated oral implants with that in the controlateral dentate side. The role of the previously reported increased innervation in the peri-implant soft tissues in the oral sensorimotor function was thus examined. Materials and Methods: Seventeen subjects with 20 implants were tested. Directional cutaneous kinaesthesia (DCK) and graphesthesia (G) were performed on the buccal side of the alveolar mucosa before and at planned intervals after implant placement. The observation was pursued until 6 months after the prosthetic rehabilitation. In each subject, the contralateral mucosa served as a control to the implant sites. Average percentages of correct responses in a four-choice task for DCK and a three-choice task for G were calculated. Results: Despite an intersubject variation in both the DCK and G, high intraindividual correlations were found (p < .005). The implant sites showed a significant difference toward the control sites at the four interval test for both tests. For DCK and G, the average of correct responses decreased after abutment connection (i.e., after the implant uncovering surgery) to increase afterwards to reach a level close to, but still lower than, the control sites 3 to 6 months after the prosthetic rehabilitation. Conclusion: The DCK and G are simple but reliable sensory tests that can be easily applied in the oral region. This prospective study indicates that tooth loss reduces tactile function compared with implant-supported prostheses. The peri-implant soft tissues could be partially involved in the osseoperception function. KEY WORDS: direction discrimination, oral implants, osseoperception, psychophysical tests, sensory changes, tactile function INTRODUCTION To evaluate oral sensorimotor function of a patient, psy- chophysical studies can be carried out determining tactile threshold levels, 1 as well as Oral Stereognostic Ability and Oral Motor Ability. 2,3 Other functional tests such as the directional cutaneous kinaesthesia (DCK) and graphaesthesia (G) have been used as early as 1858 4 but not intraorally. DCK is the ability to recognize the *Associate professor and private practice, Department of Prosth- odontics, Faculty of Dentistry, Saint-Joseph University, Campus of Medical Sciences, Damascus Road, Beirut, Lebanon and Laboratory of Oral Physiology, Department of Periodontology, Faculty of Medi- cine, Catholic University Leuven, Kapucijnenvoer, Leuven, Belgium; † professor and private practice, Department of Periodontology, Dean of the Faculty of Dentistry, Saint-Joseph University, Campus of Medical Sciences, Damascus Road, Beirut, Lebanon; ‡ professor, Department of Stomatology and Maxillo-Facial Surgery, Catholic University of Louvain, Hippocrate, Brussels, Belgium; § Emeritus Pro- fessor, Faculty of Medicine, Catholic University, Leuven, Belgium; ¶ professor, Laboratory of Oral Physiology, Department of Periodon- tology, Faculty of Medicine, Catholic University Leuven, Kapucijnen- voer, Leuven, Belgium Reprint requests: Dr. Pascale Habre-Hallage, Department of Pro- sthodontics, Faculty of Dentistry, Saint-Joseph University, Campus of Medical Sciences, Damascus Road, Beirut, Lebanon; e-mail: pascale.habrehallage@usj.edu.lb © 2009 Wiley Periodicals, Inc. DOI 10.1111/j.1708-8208.2009.00215.x 296