FUNCTIONAL DISORDERSOF THE SALIVARY GLANDS IN PATIENTS WITH COMPRESSION AND DISLOCATION DYSFUNCTION OF THE TEMPOROMANDIBULAR JOINT AND THEIR CORRECTION.

OBJECTIVE: The aim: Is to assess the functional state of parotid glands and general secretion in patients with compression, dislocation dysfunction of TMJ, to correct the revealed disorders. PATIENTS AND METHODS: Materials and methods: We examined 46 patients with dysfunction of TMJ. Examination included TMJ zonography and salivary glands sonography. We studied the general and parotid secretion, transparency, viscosity, pH of the oral fluid and the secretions of the parotid glands before and after treatment. The treatment of dysfunction and hyposialosis included the repositioning of the articular heads of the lower jaw in the correct anatomical position, the use of a repositioning plate on the posterior teeth at the compression side of the articular head, bougienage of the duct of the parotid gland, administration of 10% magnesium-mineral solution of bischofite into the gland. RESULTS: Results: In patients with TMJ dysfunction, a significant decrease in the oral fluid content was noted before treatment. The saliva transparency was reduced, the viscosity was increased, the pH was slightly acidic. A study, which was carried out a month after completion of the course of treatment showed that all the studied parameters corresponded to those in healthy individuals. CONCLUSION: Conclusions: The study confirmed that in compression and dislocation dysfunction of TMJ, there are disorders of the functional state of the salivary glands.

Hypermobility of the articular heads of the temporomandibular joint: pathology or variant of the norm?

Introduction: Among the large contingent of patients with TMJ dysfunctions, there are persons with hypermobility of the joint heads of the lower jaw. Moreover, at present, the question of the frequency of occurrence of hypermobility of articular heads of the TMJ is not reflected. The aim of the work is to find out the frequency of occurrence of hypermobility of articular head among a healthy population and to evaluate the clinical, radiological, and electromyographic characteristics of the muscular-articular complex in these individuals. Material and methods: Surveys were conducted for 476 students aged 19 to 25 years. For people with revealed articular hypermobility of the articular heads, chewing and temporal muscle electromyography, TMJ aiming zonography in a lateral projection with open and closed mouth were performed with an assessment of the correspondence of the articular fossa of the temporal bone to the size of the articular head, the location of the articular heads relative to the apex of the articular tubercle. Results: Of the examined 476 students, 95 people (20%) revealed hypermobility of the articular heads of TMJ. According to the results of clinical, functional and radiological studies of TMJ, we identified three degrees of hypermobility: light, moderately expressed, significant. With light to moderate degree of hypermobility, electromyography of the temporal and chewing muscles and TMJ zonography did not reveal a difference in performance compared to healthy ones. Most of the examined did not note functional discomfort from the joints. With a significant degree of hypermobility of the articular heads, electromyography of the temporal and chewing muscles revealed a lack of synergism in their work. On TMJ zonograms with an open mouth, the articular heads extended anteriorly beyond the tops of the articular tubercles almost under their outer base. Conclusions: It has been established that hypermobility of the joint heads of the TMJ, which does not cause signs of pathology in the form of masticatory function disorders, discoordination of the masticatory muscles and uncontrolled displacements of the lower jaw, the presence of a pain symptom should be considered as a variant of norm.

High-Temperature Rate Constants for the Reaction of Hydrogen Atoms with Tetramethoxysilane and Reactivity Analogies between Silanes and Oxygenated Hydrocarbons.

The shock-tube technique has been used to investigate the H-abstraction reaction H + Si(OCH3)4 → H2 + Si(OCH2)(OCH3)3 behind reflected shock waves. C2H5I was used as a thermal in situ source for H atoms. The experiments covered a temperature range of 1111-1238 K, and pressures of 1.3-1.4 bar. H atom concentrations were monitored with atomic resonance absorption spectrometry (ARAS). Fits to the temporal H atom concentration profiles based on a developed chemical kinetics reaction mechanism were used for determining bimolecular rate constants. Experimental total H-abstraction rate constants were well represented by the Arrhenius equation ktotal( T) = 10-9.16±0.24 exp(-25.5 ± 5.6 kJ mol-1/ RT) cm3 s-1. Transition state theory (TST) calculations based on the G4 level of theory show excellent agreement with experimentally obtained rate constants, i.e., the theory values of k( T) deviate by less than 25% from the experimental results. Regarding H abstractions, we have compared the reactivity of C-H bonds in Si(OCH3)4 with the reactivity of C-H bonds in dimethyl ether (CH3OCH3). Present experimental and theoretical results indicate that at high temperatures, i.e., T > 500 K, CH3OCH3 is a good reactivity analog to Si(OCH3)4, i.e., kH+Si(OCH3)4( T) ∼ 1.5 × kH+CH3OCH3( T). On the basis of these results, we discuss the possibility of drawing reactivity analogies between oxygenated silanes and oxygenated hydrocarbons.