Quarterly Dental Review 361

STARK M. M., NICHOLSON D. J. and SOELBERG K. B. Effects of retraction cords and elactro- surgery upon blood pressure and tissue regeneration in rhesus monkeys, J. Dent Res. 56 (1977) 881487.

Gingival retraction using chemicals or electro- surgery may produce (a) systemic haemo- dynamic effects and (6) alterations in gingival levels. This work was carried out on 3 rhesus monkeys to investigate the effects of different retraction methods.

The haeodynamic effects were assessed by blood pressure measurements taken via intracardiac end intra-arterial cannulas. The gingival margin levels were measured from fixed reference points on all the teeth. The tests were done using the various retraction techniques following the production chamfer finishing edges 0.5-I mm below the gingival crest. Four retraction techniques were studied:

1. Non-epinephrine (aluminium sul- phatel impregnated cord.

2. Eight per cent r-epinephrine impreg- nated cord.

3. Spark gap generator electrosurgical device.

4. Fully rectified current electrosurgical unit.

The non-epinephrine retraction cord pro- duced no effect on blood pressure and no loss of tissue height. The 8 per cent r- epinephrine cord resulted in an increase in blood pressure which was maintained for 20-30 minutes. No loss in gingival height resulted. The spark gap generator caused a substantial increase in blood pressure which was maintained for 25-30 minutes and also caused considerable tissue loss. The fully rectified current electrosurgical unit resulted in increased blood pressures and tissue loss.

G. A. Smith

FRY H. R. and APP G. R. Histological evaluation of the effects of intrasulcular toothbrushing on human sulcular epithelium, J. Periodonrol. 49 (1978) 163-173.

An investigation was conducted using the Butler No. 300 Adult Right Kind/Sub-G toothbrush in intrasulcular brushing, the method being used on the mandibular left posterior teeth for 30 seconds daily for a

period of 40 days. On 28 days the brushing was undertaken by the investigator and on the remaining 12 by the subject.

Comparative histological findings indicat- ed that the epithelium of the crevicular epithelium will keratinize to some degree and that keratinization appeared to increase with intrasulcular brushing. This method of brushing did, however, traumatize the inter- dental papillae in some of the subjects taking part in the study, causing progres- sively increasing irritation and tenderness. Many subjects did not find this method of brushing a simple one.

A. Bryan Wade

SPRAY J. R., GARNICK J. J., DOLES L. R. and KLAWITTER J. J. Microscopic demonstration of the position of periodontal probes, J. Periodonrol. 49 (1978) 148-152.

A graduated blade consisting of the end of a University of Michigan ‘0’ probe was inserted into the orifice, the gingival crevices and pockets of 15 anterior and premolar teeth destined for extraction in the mouths of 13 patients, whose ages ranged from 20 to 71. Subsequent histometric and microscopic evaluation of 8 specimens obtained from 6 subjects showed that the penetration of the blade was resisted by condensation of con- nective tissue. The junctional epithelium appeared to offer little resistance to the penetration of the metal probe which was inserted at a force varying between 15 and 20 g. It is concluded that the health of connective tissue in the area beneath the junctional epithelium is probably more important in limiting the apical movement of a probe than the junctional epithelium itself.

A. Bryan Wade

GELFAND l-l. B., TEN CATE A. R. and FREEMAN E. The keratinization potential of crevicular epithelium: an experimental study, J. Perio- donrol. 49 (1978) 113-I 18.

Free grafts consisting of non-keratinized crevicular epithelium and the underlying