354 Journal of Dentistry, Vol. ~/NO. 4

active lymphocytic response and severely impaired healing.

A. Bryan Wade

MILLER W. A. Experimental foreign body reectionr to toothpaste abrasives, J. Periodontol. 47 (1976) 101-103.

Pellets of talc, kaolin, colloidal silica and precipitated chalk were placed on the chorio-allantoic membrane and, in paste form contained in tubes, subcutaneously in the flanks of young adult Syrian golden hamsters and white guinea-pigs.

It was found that all these agents which are used as abrasives in toothpaste are capable of producing a foreign body granu- lomatous reaction. The author considers that such reactions can occur in humans through the introduction of these materials via ulcerated crevicular epithelium.

A. Bryan Wade

MESSER J. G. Stress in dental patients undergoing routine procedures, J. Dent. Res. 56 (1977) 362- 367.

This paper relates the stress experienced by a patient to specific dental procedures. The parameter used to assess stress was heart rate, which was measured using a photo- sensitive radial pulse monitor.

In all cases the heart rate was higher at the commencement of visits than at the end, and high stress periods were experienced just before injection and at the start of cavity preparation.

It is proposed to use this technique to assess the value of stress-reducing treatments such as hypnosis, sedation, etc.

G. A. Smith

UPTON L. G. and ROBERT R. C. Hazard im administering nitrous oxide anal- gesia: report of case, J. Am. Dent. Assoc. 94 ( 1977) 694-696. The removal of third molars in a healthy patient was conducted under nitrous oxide/ oxygen analgesia in the ratio of 40 to 60 per cent. On completion the nitrous oxide

valve was closed and the oxygen flow in- creased. Two minutes later the patient was placed upright and he indicated that he felt dizzy. The machine was checked to reaffirm that only the oxygen valve was open. The patient was reclined and he lost conscious- ness. Respirations were attempted by ‘bag- ging’ the patient with the reservoir bag. The patient exhibited cyanosis, his eyes were open and the pupils were centred and con- stricted. Respirations were faint, the pulse was strong and rapid and the blood pressure was 100/90 mm Hg.

Since the patient’s deterioration began when 106 per cent oxygen was given the source was removed. He was given an ammonia inhalant and stimulated verbally and physically. The patient responded within seconds and soon recovered consciousness.

A nitrous oxide tank was found to have been accidentally connected to the oxygen line, and the patient had been given 100 per cent nitrous oxide instead of 100 per cent oxygen. Inspection found that the pin index was no longer functional and was causing a potentially fatal gas coupling. The nurse had accidentally connected the oxy- gen and nitrous oxide tanks to the opposite gas lines.

The pin index safety system is said to make it impossible for a cylinder of one gas to be unintentionally attached to a yoke index for any other gas. It is apparent that the system is not fail-safe and anaesthetic gas cylinders should be double-checked before use.

E. Ft. Smart

WYSHAK 0. and HAUSE J. The dental hygienist, Dent. Abstr. 22 (1977) 334.

About twothirds of America’s licensed hygienists are currently practising. The hygienists, who are typically young married mothers, tend to work for one private den- tist and spend most of their time on oral prophylaxis. Nearly half of those working do so for less than 35 hours a week. Of those not working, threequarters gave family obligations as the reason.

Andrew Richardson