Expectations of sensations, discomfort and fear in dental treatment

0005-7967/84$3.00+ 0.00 Copyright 6 1984Pergamon Press Ltd

Behov. Res. Thcr. Vol. 22, No. 2, pp. 99-108, 1984 Printed in Great Britain. All nghts reserved

EXPECTATIONS OF SENSATIONS, DISCOMFORT FEAR IN DENTAL TREATMENT

AND

S. J. E. LINDSAY,‘* P. WEGE’ and .I. YATES~ ‘Department of Psychology, Institute of Psychiatry, Unive~ity of London, De Crespigny Park, London SE5 8AF, England *BP Oil Ltd, BP House, Victoria St, London SWI, England ‘Royal Dental Hospital, Leicester Square, London WC2, England (Received

9 May 1983; accepted 7 JUIJ 1983)

Summary-A hundred dental patients and 40 dentists were asked to describe the sensations, discomfort and fear which they associated with a number of dental treatments. A number of patients were also asked to describe their experiences immediately after routine conservation procedures. It was concluded that although patients could accurately anticipate the pattern of sensations involved in treatment (even if they had not experienced some of the procedures), they expected more intense sensations and greater discomfort and apprehension than they were likely to experience. Dentists expressed more realistic ideas about the sensations produced by dental treatment. The discrepancy in patients’ expectations appears to persist in spite of many disconfi~in8 experiences. the fear of treatment being fostered by discomfort and the intensity of sensations expected, by lack of experience and, to a modest degree, by un~e~ainty about the sensations anticipated. Cognitive theories of fear do not appear to explain all these influences adequately. These observations support the need for information about sensations in treatment to help not so much with the experience of dentistry but rather with its anticipation.

INTRODUCTION

It has been shown that telling Ss about the sensations they can expect during painful stimulation can limit the distress which is experienced (Johnson, 1973). In dental treatment many people are afraid because they expect discomfort (Schuurs, Duivenvoorden, Van Velzen and Verhage, 1981; Woolgrove et al., 1980). Because 41% of adults (Todd, Walker and Dodd, 1982), on account of fear delay seeking routine care, info~ation about treatment may be helpful. It would be important, therefore, to establish the nature and intensity of the discomfort which can generally be expected with the common procedures. Thus, dentists would have a reliable pool of information with which to prepare patients. This information might be obtained from patients and from dentists who were very familiar with the treatments of interest. This could be done by asking patients to describe in a standard manner, during or immediately after treatment, the sensations which they had undergone. However, some procedures such as extractions, of which many patients have had at least one experience, are not conducted frequently in general dental practice and so it would be difficult to obtain information about them. Hence, it was proposed here to ask patients and dentists to anticipate those procedures and to describe them accordingly. With certain checks on the validity of their descriptions it was hoped to determine whether dentists and patients can disc~minate several dental treatments according to the sensations involved, and to discover what descriptioni they used for this. In addition, it would be important to establish how afraid Ss were about certain procedures in order to identify those for which they need most support from dentists. It is already clear that injections and drilling are more alarming and are associated with more pain than other procedures (Kleinknecht, Klepac and Alexander, 1973; Wardle, 1982). It has been suggested that information about treatment is important because it reduces uncertainty which is frightening in Ss (Lindsay, 1983). or because it reduces the discrepancy between expected and experienced discomfort. Hence, it would be instructive to discover how certain Ss were about the sensations they associated with treatments. Knowledge about patients’ apprehensions and patients’ certainty about their expectations should help dentists establish priorities in giving information. *To whom all reprint requests should be addressed. BRT Z-A

99

100

S. J. E. LINDSAYet al.

It has been suggested that dentists underestimate patients’ discomfort during treatment (Klepac. Dowling, Hauger and McDonald, 1980) and a comparison between dentists and patients’ expectations for very familiar procedures should check dentists’ awareness of this. People must also differ in their experience of dental treatment since 40% of adults go only when in trouble to dentists while the majority seek routine care regularly (Todd and Walker, 1980). It was anticipated that inexperienced patients would have more variable and more uncertain expectations of treatment. Also, there was a possibility that experience would habituate patients to dental discomfort and apprehension (Condes-Lara, Calvo and Fernandez-Guardiola, 1981). Inexperienced patients may have a greater or otherwise different need for information compared with experienced Ss. It was possible that certainty about expectations might, however, favour apprehensiveness. Ss who were sure of experiencing intense sensations or discomfort would be more nervous than those who were less sure of undergoing such an experience. If that were so, it would suggest that accurate expectations about discomfort encourages habituation rather than a reduction of apprehension due to uncertainty (Leventhal, Brown, Shacham and Engquist, 1979). The issues here were therefore of theoretical importance. Cognitive theories of anxiety (Goldfried, 1979), especially those emphasizing self-statements, would claim that expectations of discomfort encourage patients to be nervous. It is far from clear that such expectations are disadvantageous. Expecting the worst may prevent the most distressing outcome: experiencing even more discomfort than was expected. The self-statements hypotheses would predict that the more discomfort expected, the more apprehensive would patients be. These hypotheses should also predict that certainty about discomfort would encourage apprehension. A pilot study for another investigation showed that, even for very familiar procedures, patients experience less discomfort and fear than they expect. It remains to be seen whether similar discrepancies occur for sensations also. The present study therefore obtained descriptions of the discomfort, sensations and apprehension, together with estimates of certainty and likelihood of those sensations which were expected by general dental-practice patients for a number of dental treatments. A sample of dentists were also asked to describe what they expected would be the average experience of patients in general dental practice. It was anticipated that this, together with the greater experience of dentistry in the dentists, would produce less variability in the dentists’ observations. The McGill Pain Questionnaire (MPQ; Melzack, 1975) has been found suitable for describing the pain of dental treatment as it is being experienced (Van Buren et al., 1981). A pilot study indicated that it could discriminate in the number of adjectives chosen to describe different treatments and in ratings of discomfort on Present Pain Intensity (PPI). However, the adjectives chosen were as numerous as the subjects and it would be difficult to present them as standard descriptions of sensations. Moreover, the MPQ requires to be completed under supervision, and it was also irksome for the dentists. Hence, simpler scales were constructed in which 11 adjectives, describing the sensory, evaluative and affective attributes of sensations, were each described by the 8-point rating scales of the Personal Questionnaire Rating Scale (PQRST; Mulhall, 1978). METHOD

Subjects In a general dental practice, 102 patients, approx. 30 of whom were due to come for dental treatment, were asked to attend at an earlier time to complete a questionnaire on the nature of treatment. The remaining Ss were drawn at random from the practice list. The data from 2 Ss were discarded because of omissions in completing the questionnaires. Of the remainder, 36 were female, 64 were male. The average age was 40 yr. Questionnaires were also sent to 60 qualified dentists at the Royal Dental Hospital, London, and to the clinician whose patients participated. The dentists were drawn from all specialities, oral surgery, conservation, prosthetics, orthodontics and children’s dentistry. Forty questionnaires were returned correctly answered. The questionnaire Eleven dental treatments were described as follows: (1) a matrix band being placed around a lower molar;

Sensations,

discomfort

and fear in dental

treatment

101

(2) extraction of an upper molar (not a wisdom tooth) successfully following local anaesthetic; (3) removal of hard scale with a scraper; (4) taking impressions of the upper teeth with material being kept in the mouth for 2/3 min; (5) the use of the fast compressed-air drill (which sprays water) on a top right molar following local anaesthetic; (6) the slow compressed-air drill (which vibrates a lot) being applied to a top-right molar under local anaesthetic; (7) the extraction of an upper front tooth successfully under local anaesthesia; (8) removal of a lower wisdom tooth after the gum had been cut and some bone drilled away under local anaesthetic; a (9) ‘nerve-block’ injection in the lower gum at the back of the mouth; (IO) an ‘infiltration injection’ in the gum above the upper back tooth; and (11) polishing of fillings in lower back teeth with a brush attached to the drill. The adjectives from the MPQ to describe these treatments were: throbbing, drilling, sharp, pinching, tugging, hot, tingling, sore and tender, for sensory attributes; tiring, an evaluative description; wretched and miserable, affective descriptors. The Mulhall PQRST I&point scale (absolutely none, almost none, very little, little, moderate, considerable, very considerable, maximum possible) was attached to each of the adjectives, e.g. Absolutely none

“How much of a tender sensation would be experienced”? ConsiderVery conMaximum Very Almost possible little Moderate able siderable none

After these 12 scales Ss were asked to describe the ‘degree of certainty’, on the PQRST scale, with which they had given their ratings. Then they were asked to describe the likelihood, on a percentage scale, of the experience they had described if it were possible to experience it on 100 occasions. The scale measuring intensity of discomfort (PPI) from the MPQ, “How intense would the discomfort be?: not at all, mild, discomforting, distressing, horrible, excruciating” followed, The Ss were asked then “How much apprehension would be experienced?” to be answered on the PQRST scale. Finally, the Ss were asked if they had experienced the procedure. Procedure

The patients were asked to imagine that they were undergoing each treatment and to what they would expect to experience. The dentists were asked to describe what the average experience of patients in general would be during these treatments. Because of the length of the questionnaire, 50 patients were asked to describe the treatments. The other 50 Ss were given the remaining procedures to describe. All the assessed every dental operation.

describe practice first six dentists

RESULTS Discrimination

Among

the Procedures

The patients Ratings of sensations. The patients reliably discriminated the 11 dental procedures from one another. For Group 1, a randomize,d block analysis of variance (Kirk, 1968) showed a significant effect of the treatments (F = 129.26; df = 5/3479; P c O.OOl), the sensory rating scales (F = 5.16; df= 1l/3479; P < 0.001) and the interaction between these variables (F = 10.14; df= 55/3479; P < 0.001). None of the treatments differed from any of the others on all sensory rating scales as the corresponding r-tests indicated. Figure 1 illustrates this, the HSD (“Honestly significant difference”; Kirk, 1968) shows which mean values differ significantly in z-tests of pair-wise comparisons. Similar results were recorded in Group 2, the procedures (F = 248.06; df= 5/3479; P < O.OOl), the rating scales (F = 27.44; df = 5/3479; P < 0.001) and the interaction between them (F = 9.38; df = 55/3479, P < O.OOl), all having significant effects.

S. J. E. LINDSAY er al.

102

I Maximum

possible)

+.-G

7 ‘HSD’=

Scaling

+-+

0.70

x

6

Slow x Matrix

s---o 5

Molar

clrlll band extractlon

E

o--_-o

Fig.

I. Sensations in dental treatment

d

+-+

a

&-4

expected by patients.

Ratings of apprehension. The dental treatments differed significantly in the amount of apprehension associated with them (F = 60.39; df = 51245; P < 0.001) in Group 1, and in Group 2 (F = 13.02; df = 5.45; P < 0.001). The mean ratings were 3.94 for wisdom extraction, 3.54 for incisor extractions, 3.24 for molar extractions, 2.88 for nerve-block injections, 2.62 for slow drilling, 2.38 for infiltration injections, 2.34 for fast drilling, 1.87 for the matrix band, 1.56 for polishing, 1.54 for impressions and 1.30 for scaling. Ratings of discomfort. The procedures also were associated with differing amounts of discomfort (F = 36.28; df = 51245; P -C 0.001) in Group 1, and Group 2 (F = 9.00; df = 51245; P < 0.001). Dentists Ratings of sensations. The dentists also discriminated among the treatments (F = 97.50; df = 10/5109; P < 0.001). There were differences in the average values of the rating scales (F = 51.08; df = 1l/5109; P < O.OOl), and the interaction between the variables was significant (F = 21.57; df= 1lOj5109; P < 0.001).

Table 1 shows how the procedures were discriminated. Comparisons Rating

Between

Dentists

and Patients

of sensations

The descriptions given by dentists and the first group of patients were compared. There were significant main effects for dentists/patients (F = 4.48; df = l/88; P c O.OS), the dental procedures’ (F = 84.07; df = 51445; P < 0.001) and the rating scales (F = 26.88; df = 1l/979; P < 0.001). There were also significant interaction effects between: dentists/patients and dental procedures (F = 9.33; df = 5/445; P < 0.001); dentists/patients and rating scales (F = 5.98; df = 1l/979; P < 0.001); treatments and rating scales (F = 48.90; df = 55/4895; P < 0.001); and dentist/patient, treatments and scales (F = 10.23; df = 55/4895; P c 0.001). These results indicated that although dentists (average = 1.70) gave lower ratings for sensations than did the patients (average = 2.19), this did not occur consistently for all procedures or for all rating scales (Fig. 2). Ratings

There

of apprehension

was a significant effect associated with dental treatments (F = 102.65; df = 5/440; and with the interaction of dentists/patients and treatments (F = 2.29; df 5/440;

P < 0.001) P < 0.05).

Although it appeared that dentists expected more apprehension in patients (average = 3.03) than did patients themselves (average = 1.41), this was not statistically significant (F = 2.67; df = l/88; P > 0.05). Some treatments were associated with more apprehension than others by both dentists

Matrix band Molar extraction Fast drill Slow drill Incisor extraction Wisdom extraction Polishing Impressions Infiltration injection Nerve-block injection Scaling Overall means

0.48 0.10 3.15 5.33 0.10 4.63 2.58 0.03 0.10 0.08 0.38 1.54

Drilling

2.48 0.88 I .25 I .38 I .20 I .93 0.78 0.28 2.50 3.53 3.00 1.75

Sharp 2.83 I.53 0.45 0.75 1.80 2.20 0.45 0.43 I.18 I.50 I .83 I .36

Pinching

Table

I .73 4.18 0.83 2.00 3.85 4.35 0.90 I .65 0.40 0.55 3.03 2.13

Tugging

I. The sensations Tingling 0.80 0.75 I .38 I .63 I .03 1.78 1.63 0.63 2.18 3.40 I .05 I .48

0.23 0.43 I.18 I .45 0.45 I.10 2.03 0.55 0.90 I .45 0.30 0.92

treatments

Hot

in dental Tender I .58 1.18 I.18 1.58 1.50 2.25 1.10 0.48 I .75 2.25 2.75 1.60

2.28 I.13 I .25 1.58 1.65 2.50 1.30 0.43 1.90 2.40 3.00 1.77

by dentists

Sore

expected

I.55 I .27 I .33 1.96 I .45 2.59 1.35 0.56 I .36 1.90 I.91

Overall means I .60 2.90 2.85 3.75 2.55 4.40 I.55 1.70 I.18 1.40 1.88 2.34

Tiring

2.48 2.05 3.15 2.65 4.00 1.20 2.05 1.85 2.45 I .43 2.21

I .03

Wretched

1.13 2.48 2.05 3.00 2.68 4.00 I .05 I 60 I .78 2.45 I .63 2.17

Miserable

1.08 2.48 2.05 3.08 2 67 4.00 I.13 I .83 I.81 2.45 1.53

Overall means

5

3

% 5

I-Y 5

is

6 a

3 y

Is

e

c. $ _Y

S. J.

104 ( Moximum

possible

E. LINDSAY et al.

17

6 5

( None a? all

Matnx Band t

10

Fig. 2. Sensations in dental treatment expected by dentists (0) and patients (x ).

and patients (I: = 102.68; df = 5/440; P < 0.001). With some treatments, however, the dentists during them than did the patients themselves, the expected more apprehensiveness dentist/patient x treatment interaction (F = 2.29; df = 5/440; P < 0.05) being signi~cant. Thus, dentists expected patients to be more nervous (average = 3.73) than the patients themselves anticipated (average = 2.88) during nerve-block injections but not during polishing (dentists’ average = 1.60, patients’ average = 1.56). Dentists (average = 3.28) also predicted more fear during drilling than did the patients (average = 2.34) but there was again no difference between dentists (average = 2.00) and patients (average = 1.82) for applying a matrix band. Ratings

ofdiscomfort

Again there was no significant difference between dentists and patients (I; = 0.03; df = 1; between

P > 0.05) but the dental procedures (I; = 60.76; df = 5; P < 0.001) and the interactions these variables (F = 5.6; df = 5; P < 0.001) both had significant effects.

This indicated that dentists (average = 1.58) expected less discomfort for some procedures, such as incisor extractions, than the patients (average = 2.00) while for other treatments, such as polishing, there was no difference between dentists (average = 0.73) and patients (average = 0.88). Some procedures, such as nerve-block injections (average = 1.62), were seen as more uncomfortable than others, such as polishing (average = 0.81), by both dentists and patients.

A comparison between dentists and patients for each sensory rating scale for the II treatments (132 comparisons) showed that the patients produced more variable ratings than the dentists in 91 comparisons. Only in seven of these were the patients significantly more variable by Kirk’s F,,, statistic (Kirk, 1968) than the dentists. Ejgeects of Experience

in Patients

In only the three types of extraction were there sufficient numbers for analysis of patients who had had the experience. Thirty-two had had the wisdom extraction, 36 had had the incisor extraction, while 19 had experienced removal of an upper-right molar. Apprehension

The

inexperienced patients expected significantly more apprehension (t = 2.31, df = 45, during the wisdom extraction (average = 4.34) than the experienced patients

P < 0.05)

Sensations, discomfort and fear in dental treatment ( Maxtmum

possible)

10s

7 6 c

Rating

Fig. 3. Sensations expected by experienced ( x ) and inexperienced (0)

patients for molar extraction.

(average = 3.07), more (average = 4.16) during removal of the molar than the experienced patients (average = 2.68, t = 2.60, df = 48, P < 0.05), but not significantly more (average = 3.76) than the experienced Ss (average = 2.93, df = 46, P > 0.05) with the incisor extraction.

For wisdom extractions, more discomfort (average = 2.39) was anticipated by the inexperienced patients than by the experienced Ss (average = 1.80, t = 91.53, df= 41, P < 0.01). For the incisor extraction, inexperienced patients expected more discomfort (average = 1.09) than the experienced Ss (average = 0.93, t = 138.71, df= 46, P c O.Ol), while for the molar extraction again the inexperienced patients predicted more discomfort (average = 2.16) than the experienced ss (average= 1.55, t = 38.05, df=48, P ~0.01). Sensations The ratings of sensory attributes were analysed only for extraction of an upper-right molar. This showed a significant effect of experience (F = 6.87, df = l/28, P < 0.025) and the rating scales (F = 7.02, df = 1lj308, P < O.OOl), but there was no significant interaction between these variables (F = 0.47, df = 111308, P > 0.05). This shows that the experienced Ss gave lower ratings on all scales than did the inexperienced patients. There were also consistent differences between the scales (Fig. 3). Variability

For the molar extraction the inexperienced patients gave slightly (but not significantly) more variable ratings on all sensory scales than the experienced patients. Certainty and likelihood

For the molar extraction, the inexperienced Ss were less certain (average = 3.64) about their descriptions of sensations than were ’ the patients who had undergone that experience (average = 4.88, t = 36.36, P -c 0.01). The inexperienced patients also ,attached a lesser likelihood (average = 72.21) to their descriptions of the sensations compared with the experienced Ss (average = 80.88, F = 2.79, df = 48, P < 0.01). Correlates of Expected Apprehension

The product-moment correlations between ratings of certainty and apprehension for each procedure were all low and negative. Nine of the 11 were significantly greater (P < 0.05) than zero (Table 2). For most procedures, therefore, the greater was the certainty about the sensations expected, the less nervous did the patients expect to be.

S. 3. E. LINDSAY et al.

106

Table 2. Correlates with Wisdom exIrdctlOn

Poiishmg Likelihood Certamty

-0.31 -- +0.10* -0.03*0.14

Mean sensation

0.51*

Discomfort

0.41 * 0.12** --

lP < 0.05:

**P

<

-0.18+0.14 -0.33 * 0.10. 0.82 + 0.02” 0.77 + 0.03**

0.08**

Infiltration injectton

Incisor extraction -0.2040.14 -0.35 *0.13* Tjy;ii; -L:0.03** 0.83 - r 0.02**

-02-c 0.13 -0.27+0.13* -0.73 ; 0.04** 0.76 k 0.03” -

Nerve-block injectmn -0.17 20.13 -O?Oi:O.I4 0.68 & 0.05** 0.80 * 0.03**

0.01

The correlations between estimate of likelihood and apprehension were also all negative but only five of these were significantly (P < 0.05) greater than zero. The ~orreIations between expected discomfort, mean intensity of sensations and apprehensiveness were all highly positive and significantly greater than zero. Thus the more discomfort and intense sensations anticipated, the more nervous did patients expect to be. D@erences

Between Expectations and Experience

Twenty-nine additional patients were asked to describe their expectations on the above questionnaire about only injections and drilling immediately before treatment. They were also asked immediately afterwards to describe what their experience had been. The data have been analysed for fast drilling. These patients expected more apprehension (average = 2.67) than they experienced (average = 2.03, t = 4.12, df = 28, P < 0.001) and more discomfort (average = 1.38) than they underwent (average = 0.93, t = 3.08, df = 28, P < 0.01). The intensity of the sensations (Fig. 4) was also less than expected (F = 197.88. df = 11644, P c 0.001) and this was evident for all scales, there being no significant interaction between scales and time of rating (F = 0.55, df = 1l/644, P > 0.05). There would therefore appear to be no significant differences between patients’ experience of drilling and dentists’ predictions of that experience (Fig. 4). DISCUSSION This study has examined expectations of sensations, fear and discomfort in a sample of middle-class patients in a genera1 dental practice and in a group of dentists in a teaching hospital. The patients discriminated among the dental treatments no less accurately than the dentists, although it appears that the patients overestimated the intensity of the sensations, discomfort and fear which they expected. This was concluded from an examination of fast drilling only but appeared from inspection of the data to be true for other procedures. According to descriptions of drilling it appears that dentists have more realistic ideas about sensations in dental treatment. They also, as a group, may have slightly more consistent expectations about those sensations. It is not known if dentists appreciate that patients expect more discomfort than they experience. ( Maximum

possible

17 6

Rating

4

X-X

Patvents’

predicttons

t-t

Patients’

experience

m

Dentists’

predictions

x

Fig. 4. Expected

and experienced

sensations

for fast drilling.

Sensations. expectations

and fear in dental

treatment

107

of apprehension

Illlp~~SSlOllS

Scahg

-0.4h+0.08**

-0.55 I 0.06**

-0.39 + 0.12'

-0.23 + O.ll*

0.79;

discomfort

0.03'1

0.78 ;0.03** _-

Fast

SIOW

Matrix

Molar

drill

drill

band

extraction

-0.32 i 0.10' -0.26+0.11*

-0.20~0.14

-0.49 + 0.07"

-0.13 + 0.12

-0.?7*0.13*

-im;o.10*

-m;o.10*

0.78~0.03**

0.66;0.05**

0.75 +0.04**

mT0.02**

0.73 I0.04**

0.72; _-

g.8Jl+o.o3**

0.84 * 0.02"

0.75;0.04**

0.80 + 0.03.' _-

0.04**

If dentists were to base their reassurances to patients on their knowledge of experience in treatment only, they, the dentists, might appear to be insensitive to their patients’ needs. There was a modest relationship between fear and uncertainty about sensations in treatment. This, together with the intensity of those sensations which also affects apprehension, suggests that when information about sensations is helpful to patients, it operates at least partly by reducing uncertainty. The information must, nevertheless, be chosen carefully because it has been shown that. under some circumstances, Ss may be made more distressed (Lindsay, 1983). It is possible that the correlations between certainty and apprehension would be higher where there is a greater variance in ratings of uncertainty than was generally the case here. This may occur where there are more inexperienced patients than in this study. However, the correlations for those treatments, impressions and extractions, where there was a wider variance of experience and uncertainty. were only slightly greater than for the very familiar procedures. Further investigation should examine ratings of certainty for each scale of sensation. This may be easier for Ss than assessing certainty for 12 ratings considered together. Scale-by-scale ratings of certainty may produce higher correlations with apprehension. Inexperienced patients especially, may benefit from information about sensations because they were less certain about their expectations and were more nervous according to their descriptions of extractions. It is interesting, however, that in spite of not having experienced some treatments, patients can accurately anticipate the pattern of sensations involved, and are correspondingly afraid. They are also fairly certain about their predictions, attributing on average a 72”/, likelihood to their descriptions of extractions. Thus, for the inexperienced patients as for experienced Ss, who on average associate an 82% likelihood of their expectations, information about sensations would simply confirm what they already know. It is possible that experience of treatment leads patients to be less apprehensive and to expect less discomfort and less intense sensations. This could be examined only for extractions here. However. the resulting expectations may persist at un unrealistic level in spite of many disconfirming experiences. as the analysis of drilling has shown. The persistence of fear under these circumstances, fostered by irrational beliefs about infrequent unpleasant events, has been discussed elsewhere (Lindsay, 1983). For most patients, including the most apprehensive, it is more in the anticipation rather than in the experience of treatment, that help is needed. Indeed, the discomfort and fear experienced during routine dental treatment of injections and drilling by the patients here was minimal. Studies of information given before dentistry have not concentrated on descriptions of sensations and have not been consistently successful in reducing the fear of patients before treatment (Lindsay, 1983). The effect of sensation information on anticipatory distress in dentistry remains therefore to be examined. In order to have a significant effect, information would probably have to reduce uncertainty about sensations, the, expectation of discomfort and the intensity of sensations anticipated. Dentists appear to have a consistent and valid pool of information for that purpose but they vary considerably in their confidence about their predictions. Finally. it should be noted that nervous patients often expect sudden. intense pain in treatment (Schuurs et al.. 1981). Patients’ expectations about that were not examined here but it would be important to discover whether such expectations were reduced by sensation information with a corresponding change in apprehension. A~X-rlo,~,ierie~rllenrs-The authors are grateful to the Dean and Dr G. J. Roberts. School of Dental Surgery, The Royal Dental Hospital for their aid in seeking the cooperation of the dentists in the project. to whom thanks are also due.

108

S. J. E.

LINDSAY et al.

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Kirk R.-E. (1968) Experimental Designs: Procedures for the Behnoioral Sciences. BrooksCole. Monterey. Calif. Kleinknecht R. A., Klepac R. K. and Alexander L. D. (1973) Origins and characteristics of dental fears. J. .-tm. rfent. itss. I36, 842-848. Klepac R. K., Dowling J., Hauger G. and McDonaid M. (1980) Reports of pain after dental treatment. electricai tooth pulp stimulation and cutaneous shock. J. Am. denr. Ass. 100, 692-695. Leventhai H., Brown D., Shacham S. and Engquist G. (1979) Effects of preparatory informatton about sensations, threat of pain and attention on cold pressor distress. J. Person. sot. Psychol. 37, 688-714. Lindsay S. J. E. (1983) The fear of dental treatment: a critical and theoretical analysis. In Conrriburions 10 Medical P&hology, Vol. III (Edited by Rachman S.). Pergamon Press, Oxford. Mefzack R. (1975) The McGill Pain Questionnaire: major properties and scoring methods. Puin I, 277-299. Mulhail D. J. (1978) Personal ~ffesfjo~n~ire Rapid Scaling Technique. NFER, Windsor. England. Schuurs A. H. B., Duivenvoorden H., Van Velzen S. R. T. and Verhage F. (1981) Factors Associured with Reguiarity of Dental Attendance. Staflen & Tholen-Alphen aan Den Rijn, Brussels, Belgium. Todd J. E. and Walker A. M. (1980) Adult Dental Health I: England and Wales, 1968-1978. HMSO, London. Todd J. E., Walker A. M. and Dodd P. (1982) Adult Dental Health II. HMSO, London. Van Buren J. and Kleinknecht R. A. (1979) An evaluation of the McGill Pain Questionnaire for use in denta pain assessment. Pain 6, 23-33. Wardle J. (1982) Fear of dentistry. Br. J. med. Psychof. 55, 119-126.