Kurtosis, a new variable with possible diagnostic value in analysis of jaw muscle surface EMG.

Background: There is a need for methods to compare differences of voltage levels and distribution anomalies in the study of skeletal muscle function. Calculating the kurtosis values has been found to be of value.

Aim: The aim was to record and analyse voltage and kurtosis levels of SEMG recorded bilaterally in the masseter and anterior temporalis areas during rest and clenching and to compare the kurtosis levels between controls and patients with TMJ disc dysfunction.

Is SEMG recorded "hyperactivity" during mandibular rest a sign of dysfunctional jaw muscle activity and temporomandibular disorders (TMD)?

Background: Some authors state that above-normal surface electromyography (SEMG) levels during mandibular rest (MR) are a general sign of temporomandibular disorders (TMD).

Objective: The aim was to compare SEMG levels in the masseter and anterior temporalis areas during MR between patients with disc displacement (DD) and subjects identified as healthy. The hypothesis was that average SEMG levels would be higher in the patients during MR before and after repeated clenches with maximal effort.

Gender differences in low and high pain palpation thresholds in the TMJ and neck areas.

The null hypothesis was that pain pressure thresholds are the same for young healthy males and females and do not differ between the temporomandibular joint (TMJ) and muscle sites. The aim of the current study was to compare pain pressure threshold levels using an algometer with a convex-formed contact piece and pressure increase rates similar to those in conventional finger palpation, making the conditions more like clinical examination of painful spots with commonly used physiotherapeutic methods. Healthy subjects, 12 male, mean age 22.

A preliminary anatomical study on the association of condylar and occlusal asymmetry.

The aim of this study was to test the hypothesis that condylar and occlusion asymmetry are not associated. For each of 22 skulls, the asymmetry of condyles was graded by one examiner and the asymmetry of occlusion by another examiner, both blinded to each other's evaluation, as 0 = symmetrical, 1 = mild asymmetrical and 2 = severe asymmetrical. There were 18 condyles graded the same as to their occlusion, but in four, the grades differed by one degree.

The effect of experimental occlusal interferences on nerve growth factor levels in periodontal tissues.

Objective: To test the hypothesis that experimental occlusal interferences increase the nerve growth factor (NGF) levels in periodontal tissues and cause an up-regulation of preprotachykinin-A (PPTA) mRNA.

Background: NGF is related to hyperalgesia and inflammation. PPTA mRNA, a primer of substance P, is a possible factor in the aetiology of pain.

Magnetic resonance imaging on TMJ disc thickness in TMD patients: a pilot study.

Statement Of Problem: Studies of temporomandibular joint (TMJ) discs removed from autopsy specimens and in surgery indicate that they are often thicker in patients with temporomandibular disorders (TMDs). Disc thickness may also change when the condyle moves in and out of the joint fossa during opening and closing.

Purpose: The purpose of this pilot study was to test the hypothesis that the TMJ disc thickness is greater in TMD patients than in healthy subjects and is affected by the degree of jaw opening.

Experimentally created nonbalanced occlusion effects on the thickness of the temporomandibular joint disc in rats.

Objectives: To test the hypothesis that experimentally created physiologically nonbalanced occlusion will not affect the thickness of the temporomandibular joint (TMJ) discs in rats.

Material And Methods: Twenty-four 8-week-old Sprague-Dawley rats were equally divided into a control group that was left untreated and an experimental group where a nonbalanced occlusion was created. Elastic rubber bands, 1 mm in diameter, were inserted and 1 week later were replaced by plastic material between the first and the second molars of the left maxillary and the right mandibular dentitions to move the first molars about 0.

The effect of physiological nonbalanced occlusion on the thickness of the temporomandibular joint disc: a pilot autopsy study.

Statement Of Problem: The temporomandibular joint (TMJ) disc is often observed to be thicker in temporomandibular disorder (TMD) patients. This clinical observation requires verification.

Purpose: The purpose of this pilot study was to investigate whether the TMJ disc responds to dysfunctional occlusal changes by an increase in thickness.

Inaudible temporomandibular joint vibrations.

The aim was to test the hypothesis that inaudible vibrations with significant amounts of energy increasing during jaw movements can be recorded in the temporomandibular joint (TMJ) area. Twenty one subjects, who could perform wide opening movements without feeling discomfort, 12 with and 9 without TMJ sounds audible at conventional auscultation with a stethoscope, were included. Recordings were made during opening-closing, 2/s without tooth contact, and during mandibular rest, using accelerometers with a flat frequency response between the filter cutoff frequencies 0.