DISTRIBUTION OF THE EFFORTS OF THE MUSCLE MUSCLES HUMAN DENTAL SYSTEM AT ASYMMETRIC TONE SURFACE MASKING MUSCLES

The dentofacial system is closely related to the musculoskeletal, digestive, nervous, cardiovascular systems, etc. The functioning of the dentofacial system affects nutrition, breathing, swallowing, speech, hearing, etc., where occlusion is one of its main parameters. Many pathologies in the dentofacial system are also associated with a change in the efforts of the masticatory muscles, where hypertonicity of the superficial masticatory muscle is most common. The article considers an example of her hypertonicity by biomechanical modelling. For this, the problem of determining of the masticatory muscle efforts was solved at the maximum value of the force of compression of the jaws, which was 600 N. The cases were considered when the minimum possible value of the force of the superficial masticatory muscle was 70%, 80% and 90% of the maximum value. It was found that for the case while the minimum values of the efforts of all masticatory muscles do not exceed 50% of their maximum possible values, then the distribution of muscle efforts remains unchanged, i.e. the values of muscle efforts do not change. When at least one of the muscles exceeds its half of the maximum possible effort, it is observed that the efforts of the remaining muscles on the same side of the face decrease or remain approximately at the same level, and on the opposite side, the muscle efforts initially decrease, and at 80% and 90% of the maximum possible magnitude of the effort of the superficial chewing muscle increases again. In further works, various combinations of hypertonicity of the masticatory muscles, as well as the hypotonia of these muscles, are assumed.

Translocation Relative to Range

A standardized index for effect intensity, the translocation relative to range (TRR), is discussed. TRR is defined as the difference between the expectations of an outcome under two conditions (the absolute increment) divided by the maximum possible amount for that difference. TRR measures the shift caused by a factor relative to the maximum possible magnitude of that shift. For binary outcomes, TRR simply equals the risk difference, also known as the inverse number needed to treat. TRR ranges from –1 to 1 but is – unlike a correlation coefficient – a measure for effect intensity, because it does not rely on variance parameters in a certain population as do effect size measures (e.g., correlations, Cohen’s d). However, the use of TRR is restricted on outcomes with fixed and meaningful endpoints given, for instance, for meaningful psychological questionnaires or Likert scales. The use of TRR vs. Cohen’s d is illustrated with three examples from Psychological Science 2006 (issues 5 through 8). It is argued that, whenever TRR applies, it should complement Cohen’s d to avoid the problems related to the latter. In any case, the absolute increment should complement d.

Statistical estimation of seismic hazard parameters: Maximum possible magnitude and related parameters

The problem of statistical estimation of earthquake hazard parameters is considered. The emphasis is on estimation of the maximum regional magnitude, Mmax, and the maximum magnitude, Mmax(T), in a future time interval T and quantiles of its distribution. Two estimators are suggested: an unbiased estimator with the lowest possible variance and a Bayesian estimator. As an illustration, these methods are applied for the estimation of Mmax and related parameters in California and Italy.