Fabrication of removable stone dies using cemented dowel pins.

Proper dowel pin placement in the working cast is important in the fabrication of a cast restoration. A technique is suggested whereby the dowel pin is orientated and cemented after the working cast has been separated from the impression. This procedure produces a working die that has a correctly positioned dowel pin, is stable, and can be repeatedly returned to its original relationship. A technique is suggested whereby the dowel pin is orientated and cemented after the working cast has been separated from the impression. This procedure produces a working die that has a correctly positioned dowel pin, is stable, and can be repeatedly returned to its original relationship.     

Cyclic AMP.

Cyclic AMP mediates the effects of many hormones on their target cells. Some of the mechanisms by which this occurs are discussed in this review. The role of cyclic AMP in regulating glycogen metabolism in liver and skeletal muscle is firmly established. Data suggesting that cyclic AMP mediates hormonally stimulated salivary gland amylase secretion, cardiac muscle contractility, smooth muscle relaxation, and platelet aggregation are summarized.     

Fluorine and tin uptake by enamel studied by x-ray photoelectron spectroscopy (ESCA).

ESCA has been combined with argon-ion etching to obtain depth profiles for SnF2-treated enamel. Three zones of products from the topical treatment are detected: a layer of tin oxide on the surface; fluoroapatite + hydroxyapatite at depths below about 0.2 micron; an intermediate layer CaF2, Sn(OH)2, Sn2PO4OH, and fluoroapatite between the two. Sn3F3PO4 was not detected.     

Electromyographic silent periods and jaw motion parameters: quantitative measures of temporomandibular joint dysfunction.

The purpose of this research was to compare, in the subjects, the duration of the EMG silent period with jaw motion error. The results indicate that both jaw motion error and silent period duration are large in patients with TMJ-muscle-pain dysfunction, both are small in normal subjects, and both are small in successfully treated patients. There is a statistically significant correlation (r=0.91; P less than 0.01) between the two diagnostic parameters of TMJ-muscle-pain dysfunction.     

Ultrastructure of fenestrated capillaries in human dental pulps.

Dental pulps of both the primary and permanent dentitions were studied. Fenestrated capillaries were found at varying depths within the odontoblast layer in the root and crown portions of pulps. The fenestrae were in the attenuated part of the endothelial cell cytoplasm away from the nucleus. They averaged 60 nm in diameter and were bridged by a membrane or diaphragm approximately 7 nm thick.     

An overhead projection aid for teaching the principle of occlusion

A technique has been presented whereby models which can be animated are used to form a projected image on a screen and thereby demonstrate the principles of occlusion together with principles of articulators. The system can be used alone or in conjunction with clinical slides interjected at relevant places in the discussion. This technique has been found to be a very useful aid in the teaching of occlusion to both graduate and undergraduate students.     

A proposed classification for heritable human dentine defects with a description of a new entity

A newly recognized heritable dentine defect is described which is manifested as an amber, translucent colouration and total pulpal obliteration in all primary teeth. Permanent teeth have a thistle-tube pulp configuration with ubiquitous pulp stones and normal colouration.The unusual finding of true denticles in these heritable dentine defects may represent the induction of odontoblastic differentiation by aberrant epigenetic factors produced in the abnormally developing dentine.A classification for the heritable dentine defects is proposed which consists of two distinguishable groups; the dentine dysplasias and the dentinogenesis imperfectas.