Diagnostic criteria for temporomandibular disorders (DC/TMD): interexaminer reliability of the Finnish version of Axis I clinical diagnoses.

Recently, updated diagnostic criteria for temporomandibular disorders (DC/TMD) were published to assess TMD in a standardised way in clinical and research settings. The DC/TMD protocol has been translated into Finnish using specific cultural equivalency procedures. To assess the interexaminer reliability using the Finnish translations of the DC/TMD-FIN Axis I clinical diagnostic assessment instruments. Reliability assessment data were collected during a 1-day DC/TMD Examiner Training Course at the University of Turku, Finland, in collaboration with the International DC/TMD Training and Calibration Center in Malmö University. Clinical TMD examinations according to the Finnish pre-final version of the DC/TMD Axis I assessment protocol were performed by four experienced TMD specialists on altogether 16 models. Kappa coefficient, overall percentage agreement (%A) as well as positive (PA) and negative (NA) agreements were used to define the reliability. Myofascial pain with referral, headache attributed to TMD and disc displacement (DD) without reduction without limited opening showed excellent kappa values (range 0·87-1·00). Fair-to-good reliability was observed for diagnoses of myalgia (k = 0·67), arthralgia (k = 0·71) and DD with reduction (k = 0·64). The PA was high for all pain-related diagnoses and DD without reduction without limited opening (medians ≥83%), and acceptable for DD with reduction (median 67%). The NA was high (medians ≥87%) for all DC/TMD diagnoses, except for myalgia which showed acceptable NA (median 75%). The %A was high for all assessed diagnoses (medians >85%). The findings of this study showed DC/TMD-FIN Axis I to demonstrate sufficiently high reliability for pain-related TMD diagnoses.

Peripheral nervous system involvement in primary burning mouth syndrome--results of a pilot study.

OBJECTIVE: The pathophysiology of primary burning mouth syndrome (BMS) has remained enigmatic, but recent studies suggest pathology within the nervous system at multiple levels. This study aimed to investigate in detail the contribution of either focal or generalized alterations within the peripheral nervous system (PNS) in the etiopathogenesis of BMS. SUBJECTS AND METHODS: Intraepithelial nerve fiber density (IENFD) of tongue mucosa was assessed in 10 carefully characterized BMS, and the results were compared to 19 age- and gender-matched cadaver controls, 6 with lifetime diabetes. Extensive neurophysiologic and psychophysical examinations of the trigeminal system and distal extremities were performed to profile PNS function in BMS. RESULTS: Patients with BMS had significantly fewer intraepithelial nerve fibers (0,27, s.e. 0,18 mm(-1); P = 0.0253) than non-diabetic controls (0,92, s.e. 0,15 mm(-1)). In the subepithelial space, the amount of nerve fibers did not differ between the groups. The majority (9/10) of patients with BMS showed neurophysiologic or psychophysical signs of a more generalized PNS dysfunction. CONCLUSIONS: Our results in neurophysiologically optimally characterized BMS patients confirm that pure focal small fiber neuropathy of the oral mucosa has a role in the pathophysiology of primary BMS. Furthermore, BMS may be related to a more generalized, yet subclinical peripheral neuropathy.

Pathophysiology of primary burning mouth syndrome with special focus on taste dysfunction: a review.

Primary burning mouth syndrome (BMS) is a chronic oral condition characterized by burning pain often accompanied with taste dysfunction and xerostomia. The most compelling evidence concerning BMS pathophysiology comes from studies on the somatosensory system using neurophysiologic or psychophysical methods such as blink reflex, thermal quantitative sensory testing, as well as functional brain imaging. They have provided convincing evidence for neuropathic involvement at several levels of the somatosensory system in BMS pain pathophysiology. The number of taste function studies trying to substantiate the subjective taste disturbances or studies on salivary factors in BMS is much more limited, and most of them suffer from definitional and methodological problems. This review aims to critically evaluate the existing literature on the pathophysiology of BMS, paying special attention to the correctness of case selection and the methodology used in published studies, and to summarize the current state of knowledge. Based on the recognition of several gaps in the current understanding of the pathophysiology of BMS especially as regards taste and pain system interactions, the review ends with future scenarios for research in this area.

Sensory regeneration following intraoperatively verified trigeminal nerve injury.

OBJECTIVE: To follow recovery of sensory function mediated by both myelinated and unmyelinated axons in relation to the type of inferior alveolar nerve (IAN) injury. METHODS: The authors assessed the function of afferent Abeta-, Adelta-, and C-fibers of the IAN using neurophysiologic (mental nerve blink reflex, sensory nerve conduction [NCS] of the IAN) and quantitative sensory tests (QST; cold, warm, heat pain, and tactile modalities). The tests were done 2 weeks, 1, 3, 6, and 12 months postoperatively and compared to the preoperative baseline in 20 patients undergoing mandibular bilateral sagittal split osteotomy. Nineteen patients underwent intraoperative monitoring. RESULTS: In primarily demyelinating injuries (21/40 nerves), the sensory alteration and all tests normalized on the group level within the first 3 months. After partial axonal lesions (15/40 nerves), neurophysiologic and thermal QST results remained abnormal at 1-year control in a high proportion of the IAN distributions (up to 67%). At 1 year, the tactile QST was abnormal in 40%, but the NCS in 87% of the symptomatic IAN distributions. Neuropathic pain occurred in 5% of the patients, only after severe axonal damage. CONCLUSIONS: Sensory nerve conduction and thermal quantitative sensory testing showed incomplete sensory regeneration at 1 year after axonal trigeminal nerve damage. Clinical examination with tactile quantitative sensory testing was less reliable in the follow-up of sensory recovery. Sensory Abeta-, Adelta-, and C-fibers recovered function at similar rates. The trigeminal nerve does not differ from other peripheral nerves as regards susceptibility to neuropathic pain.

Recovery of nerve injury after mandibular sagittal split osteotomy. Diagnostic value of clinical and electrophysiologic tests in the follow-up.

The diagnostic value of several clinical, quantitative sensory tests (brush-stroke directional discrimination (BSD), touch detection threshold (TD), warm/cold (W/C) and sharp/blunt discrimination (S/B)), and electrophysiologic tests (mental nerve blink reflex (BR), nerve conduction study (NCS), cold (CDT), and warm (WDT) detection thresholds) in the recovery of inferior alveolar nerve (IAN) injury was evaluated in a prospective 1-year follow-up study of 20 patients after bilateral sagittal split osteotomy (BSSO). The subjective sensory alteration was assessed from patients' drawings. The predictive values of different tests at 2 weeks were determined in relation to the subjective sensory recovery at 12 months. The most pronounced recovery of the nerve damage occurred during the first 3 months according to all measures used. After 3 months, the electrophysiologic tests, especially the NCS, indicated significant further improvement. Except for the TD test, all other clinical test results were normal already at 3 months postoperatively. At early and late controls, the NCS and the thermal quantitative sensory testing could best verify the subjective sensory alteration, and most accurately assess the degree of thick and thin fibre dysfunction. At 1 year, the nerve dysfunction, as revealed by the NCS, corresponded with the figures of sensory alteration reported by the patients (35% R, 40% L). The W/C, BSD, S/B and WDT tests had the best early positive predictive values. Electrophysiologic tests had higher negative predictive values compared to clinical tests.

An evaluation of clinical and electrophysiologic tests in nerve injury diagnosis after mandibular sagittal split osteotomy.

The yield of clinical sensory tests and electrophysiologic tests in the diagnostics of inferior alveolar nerve (IAN) damage after bilateral sagittal split osteotomy (BSSO) was studied. The diagnostic value of these tests was evaluated by comparing the test results to the degree of nerve damage at the end of the operation as documented by means of the intraoperative nerve conduction recording of the IAN. Twenty patients undergoing BSSO were analysed preoperatively and 2 weeks postoperatively. The frequency of the IAN disturbance ranged from 10% to 94% depending on the test method and the test site used. Of the clinical sensory tests, the touch detection threshold (TD) test was the most sensitive and clinically useful test. It also correlated best with the electrophysiologically verified intraoperative nerve damage (R = -0.603, P = 0.017 on the right, R = -0.626, P = 0.01 on the left). The blink reflex and quantitative cold detection threshold tests were almost as often abnormal as the TD-test, but nerve conduction study (NCS) was the most sensitive (88%) of all clinical and electrophysiologic tests. The frequency of abnormal findings in the electrophysiologic tests indicating IAN injury, 75% on the right side and 90% on the left side, corresponded exactly with the figures of subjective sensory alteration. Almost all electrophysiologic tests showed obvious associations with the objectively verified IAN damage. All tests, except the NCS, showed only moderate sensitivity. Specificity of the tests was generally high, the only exceptions being the TD test and the NCS. To increase the diagnostic accuracy of the testing and to detect different types of damage in different nerve fibre populations, a combination of different sensory and electrophysiologic tests is recommended.

Risk factors of nerve injury during mandibular sagittal split osteotomy.

There is little objective data about whether surgical technique or mandibular anatomy are a risk for inferior alveolar nerve (IAN) injury during bilateral sagittal split osteotomy (BSSO). Orthodromic sensory nerve action potentials (SNAPs) of the IAN were continuously recorded on both sides in 20 patients with mandibular retrognathia during BSSO operation. Changes in latency, amplitude, and sensory nerve conduction velocity (SNCV) at baseline and at different stages of the operation were analyzed. The SNAP latencies prolonged, the amplitudes diminished, and the SNCVs slowed down during BSSO (P = 0.0000 for all parameters). The most obvious changes occurred during surgical procedures on the medial side of the mandibular ramus. There was a clear tendency towards more disturbed IAN conduction with longer duration of these procedures (right side R = -0.529. P = 0.02; left side R = -0.605, P = 0.006). Exposure or manipulation of the IAN usually had no effect on nerve function, but the IAN conduction tended to be more disturbed in cases with nerve laceration. Low corpus height (R = 0.802, P = 0.001) and the location of the mandibular canal near the inferior border of the mandible (R = 0.52, P = 0.02) may increase the risk of IAN injury. There was no correlation between the age of the patients and the electrophysiological grade of nerve damage.

Intraoperative monitoring of the inferior alveolar nerve during mandibular sagittal-split osteotomy.

In order to evaluate the risk of nerve injury and to prevent iatrogenic damage at different stages of bilateral sagittal-split osteotomy (BSSO) of the mandible, we monitored the function of the inferior alveolar nerve (IAN) continuously on both sides in 13 orthognathic patients undergoing BSSO. The IAN was stimulated at the mental foramen with two monopolar needle electrodes fixed to the dental splint, and the orthodromic sensory nerve action potentials (SNAP) of the IAN were recorded with a silver-wire electrode inserted near the oval foramen on each side. The latencies, amplitudes, and sensory nerve conduction velocities at baseline, after medial opening, sawing, splitting, eventual manipulation, and fixation of the mandible were analyzed. The monitoring method functioned technically well in 25 of 26 nerves. Both the surgical technique and the duration of medial opening had conspicuous effects on the function of the IAN, which led us to modify the medial approach. When finer instruments were used for retraction and the duration of medial opening was shortened to less than 10 min, the SNAP of the IAN was always preserved at this stage. Monitoring of the IAN also prevented nerve injury during splitting and fixation. This technique for intraoperative monitoring of the IAN seems to be a feasible and promising tool for objective evaluation of intraoperative events and for prevention of nerve injury during BSSO.