A bibliographical survey of bruxism with special emphasis on non-traditional treatment modalities.

After proposing a common-sense definition of bruxism, this partial review distills its various symptoms and consequences from the literature. That literature suggests that the splint-the most popular treatment modality-falls short in some respects. The research literature is even less sanguine about the efficacy of such other traditional therapies as sound alarms and stress reduction. Given the limited success of traditional approaches, and given, moreover, the high incidence of bruxism and its harmful consequences, clinicians may occasionally be interested in experimenting with non-intrusive, safe, less widely known, treatment modalities. To meet this need, this review-unlike all other reviews of the subject-focuses on such comparatively unpopular or recent approaches.

Can taste aversion prevent bruxism?

The first part of this note sketches a biofeedback modality for the treatment of bruxism. A mildly aversive, safe liquid is inserted into, and sealed in, small, bilaterally sleeved, polyethylene capsules. Two capsules are attached to a simple dental appliance that comfortably and securely places them between the lower and upper back teeth. The appliance and capsules are worn at night or at other times when bruxism is suspected to occur. Whenever a sleeping or an awake patient attempts to brux, one or both capsules rupture and the liquid is released into the mouth. The liquid then draws the patient's conscious attention to, and forestalls, any attempt of teeth clenching or grinding. Variations of the method and device can be used to diagnose bruxism. The second part of this note describes the long-term application of this taste-based approach to one chronic bruxer.

On the interpretation of mutagenically induced mosaicism in Drosophila.

This paper draws attention to the formal parallelism that exists between chromosomal-loss mosaicism and mutagenically induced mosaicism in Drosophila and suggests that, although the underlying processes by which these two types of genetic mosaics are generated are very different, the more refined methodology employed in developmental analyses of genetically induced chromosomal-loss mosaics may be profitably extrapolated to mutagenesis studies. Results obtained from various studies of genetically induced mosaics and from a previous EMS mutation induction experiment at the yellow locus are utilized to illustrate this methodology and to estimate the total mutagenicity rates of EMS.-The following are some of the tentative conclusions that have been drawn in this report regarding an EMS concentration that produced 31% F(2) lethals in the standard X-linked recessive lethal test: (1) The frequency of cuticular mosaics is at least 5 times that of F(3) lethals. (2) At least 60% of all cuticular mosaics go undetected in the standard X -linked recessive lethal test since their mutant tissue does not extend into the germ line. (3) The frequency of EMS-induced cryptic mosaics is probably less than 10% the frequency of cuticular mosaics. (4) Some EMS-induced mutations are probably bona fide completes; if confirmed, this inference must be taken into consideration in estimating the total mutagenicity rates of this agent and in molecular interpretations of its mechanism of action. (5) The fact that the proportion of mutant tissue in EMS-induced mosaics is greater than 25% is consistent with the suggestion that the action of EMS is occasionally delayed until after the first cleavage division of the embryo. (6) Such an EMS concentration causes on the average more than 5 independent genetic alterations in the entire haploid genome of an X-bearing sperm.-This report clarifies the experimental evidence that must be generated, and the methodology that can be used to analyze this evidence, if it is of interest to render these and related conclusions regarding the effect of EMS on D. melanogaster more accurate, or if it is of interest to conduct a similar analysis for other mutagens that cause a significant degree of mosaicism.

A method for estimating the number of blastoderm cells which give rise to Drosophila imaginal discs.

A mathematical method for calculating the number of blastoderm cells whose descendants form the various imaginal discs is described. The method differs from available approaches in two respects: (1) It is based only upon the frequency of mosaicism of the adult derivatives of a given imaginal disc and ignores the relative surface area of the two genetically marked cell populations which comprise these derivatives. (2) The method estimates the average number of cells at the blastoderm stage which give rise to a particular imaginal disc and not at the developmental stage at which restriction of the pool of cells which will form this imaginal disc occurs. Despite their methodological differences the estimates obtained from this method and from other approaches are of the same order of magnitude and thus provide further support to the currently available estimates and to the notion that restriction of whole imaginal discs occurs at the blastoderm stage. The proposed method also provides a quantitative approximation of the non-linear relationship that exists between the frequencies of mosaicism of different imaginal discs and the number of cells which comprise these discs.

A new behavioral bioassay for an analysis of sexual attraction and pheromones in insects.

Drosophila melanogaster gynandromorphs were introduced into a mating chamber containing two wild type males. From the differential courtship responses of these males it could be concluded that the only important factor which enables a male to distinguish between conspecific males and females and to direct persistent courtship only toward females is tissue composition of females. This fact is interpreted in terms of a female-specific sex pheromone. Most of this pheromone is produced by cells whose precursors on the blastoderm surface are very close to, or identical with, the blastoderm precursors of the tergites. Some of this pheromone is probably produced by cells whose precursors are very close to, or identical with, the precursors of the sternites and thorax.