Fred M. Sorenson

The miniature pig as an experimental animal in dental research

Abstract The embryological development of the pig has long been recognized as very comparable to that found in man. That this similarity should extend beyond developmental anatomy into some phases of adult morphology and physiology is not surprising and indeed has been shown by many investigators. With miniature pigs available, the main disadBANtages of studying the pig are eliminated, namely, the rapid growth and great size achieved. With the knowledge that the miniature pig is an omnivorous animal, possesses deciduous and permanent sets of teeth, and displays both chewing and biting actions of the mandible, it would appear that this animal would be well suited to research programmes in the field of dentistry. It was the intent of this investigation to examine the miniature pig as a possible laboratory animal for different types of dental research activities. Handling and housing of miniature swine was done without difficulty, with cost and maintenance comparing favourably with that of other large laboratory animals. Blood, pure parotid and whole saliva, and tooth scrapings for bacteriological assay were easily obtainable. With the anaesthetized pig it was possible to perform routine dental procedures and operations, using standard dental equipment. Access was good and the types of procedures used in this investigation indicate that use of the pig may be a means of further developing dental research methods.

Thermal Pulp Tester: A New Instrument

Considerable attention has been given, in the past, to the response of dental pulp to thermal stimulation.1 6 However, knowledge of normal threshold values and of abnormal pulpal response to temperature change remains limited. The purpose of this paper is to describe temperature-controlling and monitoring equipment that the authors have developed and are now using in testing dental thermal sensitivity and which, we believe, makes practical more accurate studies of response to dental temperature stimulation than have heretofore been achieved. The apparatus was designed and constructed to perform the following three major functions: (1) to deliver water at any desired temperature between approximately O0

Presence of Se75 in Rat Saliva after Intracardiac Injection of Radioactive Sodium Selenite

The present study was planned to determine whether or not the major salivary glands of the rat are permeable to selenium in the form of a buffered selenite administered directly into a heart chamber. Nineteen male Sprague-Dawley albino rats, weighing approximately 250 gm., were ether-anesthetized and given intracardiac injections of 0.1 ml. of sodium selenite, phosphate-buffered to pH 6.8. Including the carrier selenium, each animal in a group received 37.5 mg of Se which contained 28 microcuries of radioactivity. At intervals of 2, 3, 5, 9, and 24 hours after isotope injection, each animal was anesthetized with nembutal (3 mg/100 gm) and then given pilocarpine nitrate, 5.0 mg/kg, subcutaneously. Following the injection of the sialagogue, saliva was collected from the anesthetized rats in test tubes, using a plastic animal holder. At the conclusion of a 10-minute collection period, each

Method for Measuring Temperature Changes in the Tooth during Restorative Procedures

With the advent of handpieces operating in the 100,000 r.p.m.-and-over range, there has been much renewed interest in the possible effects of temperature change within teeth during cavity preparation. Many attempts to quantitate temperature rise in cavity preparation have been made and reported. Considerable variation in the reported data is not surprising in view of the many technical factors that might act to influence significantly the production and measurement of temperature. Several important aspects of this problem that have not been adequately described or standardized in the past are (1) fidelity of temperature reception and recording, (2) quantitative and qualitative aspects of force application of potential thermogenic sources, and (3) site and detector orientation within the tooth for thermal observation. It is the purpose of this paper to describe methods and instrumentation that allow control and evaluation of these important variables.

Photoelectric Method for Quantitative Evaluation of Mast-Cell-Associated Enzyme Activity in Human Gingival Tissues

Simple counts of mast cells per unit of human gingiva are often difficult to interpret because of the large numbers and varying sizes and shapes of the counted structures. The relatively simple photoelectric scanning method described herein eliminates tedious counting procedures while providing a measure of the relative quantity of stainable mast cell granules within the area scanned. Thus, the method may provide a better estimate of the total biologic activity than would simple mast cell counts.