Repeatability of 5 clinical neurosensory tests used in orthognathic surgery

Many patients undergoing orthognathic surgery experience some degree of neurosensory impairment as a normal consequence of surgery. This may also occur as a complication after mandibular third molar surgery. The condition is usually reversible, but it may also be permanent. Neurosensory tests are essential in making decisions regarding the nature of the nerve injury, the potential for recovery, and the possible need for secondary microneurosurgical intervention. The aim of this study was to evaluate the repeatability of 5 clinical neurosensory tests assessing the neurosensory function of the inferior alveolar nerve (IAN). Twenty healthy subjects (9 males, 11 females) ranging in age from 21 years to 27 years participated in this study. The methods of assessment were light touch (LT), 2-point discrimination (2-P), pin tactile discrimination (PIN), thermal discrimination, and sensibility (ST) testing of the mandibular teeth with a vitality scanner. All the measurements were evaluated by 2 examiners and repeated at an interval of 6 months. In the statistical analysis, intraexaminer and interexaminer variability, as well as the variability between the 2 observations at a 6-month interval, were calculated. All the subjects reacted positively to LT and thermal discrimination in every observation. For the 2-P and PIN tests, intraexaminer variability was smaller than interexaminer variability, and repeatability of the 2 observations at 6 months was also good. Repeatability of ST was best at incisors, but it was not numerically very accurate at any site. However, all teeth that reacted positively to the vitality scanner in the first observation also reacted positively in the second observation; this instrument thus provides a more meaningful measurement of neurosensory function as a positive/negative assessment than as a numeric value.