D. A. Stewardson & E. S. McHugh.
Conservative Dentistry, School of Dentistry, University of Birmingham, Birmingham, UK.
Department of Statistics, University of Glasgow, Glasgow, UK.

Introduction.
The positive benefits to operator and patient of using rubber dam (RD), particularly for endodontic treatment are well recognized (European Society of Endodontology 1994). In all the dental schools in UK the use of rubber dam is encouraged for many operative procedures and is mandatory when students undertake root-canal treatment. However, rubber dam is rarely used even for endodontics in general practice (British Endodontic Society 1983). Numerous reasons are given for not using it (Marshall & Page 1990). One of the main reasons being that patients do not like its use. Other practitioners (Reuter1983, Jones & Reid1988, Gergely1989) have suggested that there is no problem with patient acceptance. Reuter (1983) offered anecdotal evidence that, based on extensive personal experience, his patients preferred the use of rubber dam for restorative procedures. Gergely (1989) interviewed 72 of his patients and found that approximately 72% expressed a preference for treatment with rubber dam. Eight percent preferred treatment without, and1 9% had no preference. In this study, however, the interviews were conducted by the clinician which may have influenced the way the patient responded. Jones & Reid (1988) surveyed the opinions of 100 patients attending a child dental health unit for treatment. The patients were interviewed and also completed a questionnaire. A consensus on the patient’s opinion was reached by the operator and the patient’s mother where the child was too young to understand the questions. They concluded that 79% of their patients demonstrated good acceptance of rubber dam. This research has the same limitation as that of Gergely (1989). In addition, some of the responses were not given by the patient themselves, and the responses from children may be influenced by different factors from those of adults.
The aims of the present survey were:

1. To record patients views of their experience of rubber dam use in an objective manner.
2. To evaluate the influence of some personal and clinical factors on patients’opinion.

Materials and method.
A simple confidential questionnaire containing10 questions was designed. The questionnaire drew on work by previous investigators (Jones & Reid1988, Gergely1989) and was also designed to gain information that is considered pertinent by the authors (Fig.1).
The questions enquired in to:

• Personal details of age and gender.
• The patient’s previous experience of RD use.
• Their current experience.
• Their preference for future RD use.

Also entered on the form was:

• The type of procedure being carried out.
• The time taken to apply the dam.
• The approximate duration of its use.

It was decided to undertake this survey amongst two groups of patients; adult patients who were receiving dental treatment under RD from,

• (a) final-year dental students at Birmingham Dental School, UK (student patients, SP), and
• (b ) four general dental practitioners (DP).

Figure 1. Questionnaire used to gather information.

The intention was to enable an assessment to be made concerning the influence of the operator’s experience on the patient’s views regarding RD. Patients were asked, at the end of their appointment, to complete the questionnaire. This was undertaken in the waiting area, and the patients in group SP then passed the form to the receptionist for subsequent collection. Group DP patients were provided with a stamped addressed envelope to return the form to the author. The information concerning procedure, application time and duration were entered by the supervising clinician at the dental school, and by the practitioner’s assistant in the practices. As far as possible, the students and dentists were not in volved in the survey process, and the patient was assured that the forms were anonymous and confidential. Patients were only asked to complete one form each; some students would have more than one of their patients included in the survey. No students had more than three of their patients included. The dentists who participated we re responding to a request made for volunteers at a postgraduate course held at the Birmingham Dental School. They were all male, non-specialists who provided the majority of their dental treatment out with the National Health Service. Three graduated in the early eighties and one in the early sixties. Each had reported that they utilized RD for over 75% of endodontic treatment and posterior composite placement, and for approximately 50% of anterior composite placement.
The survey was continued until 100 forms had been collected from group SP that had been correctly completed. The dentists were provided with 30 forms each in order to achieve 100 returned useable forms and to make allowance for non-responses. Data from the completed question aires were entered into a database and subsequently analyzed using statistical package for the social sciences (SPSS). Analyses were confined to simple cross-tabulations of the patients’responses and potential associated factors, using w2- and appropriate follow-up tests as necessary.

Group SP.
Before the target of100 was achieved, seven forms were discarded of which four had not been fully completed by the patient, and three had not had the timings entered on the reverse. Patients ranged from 17 to 84 years in age with 48 females and5 2 males. The distribution of patients’ages and genders is shown in Fig. 2. The types and number of procedures being carried out were

• (a) endodontics (n = 68),
• (b) plastic restorations (amalgam and composite) (n = 25), and
• (c) cementation of etch retained bridges (n = 7).

For this patient group, 6% had found their current experience of RD pleasant, 52% comfortable, whilst 40% felt it was uncomfortable, and 2 % found it painful. When asked whet her they would prefer RD to be used at their next appointment, 43% said yes, 13% said no, with 44% expressing no preference.

Group DP.
Of the 120 forms distributed amongst the dentists’ patients, 106 were returned correctly completed, a response rate of 88%. Of the other 14, six had not been returned, four had not been fully completed by the patient, and four had timing or procedure information missing. Patients ranged from17 to 85 years in age with 64 females and4 2 males. The distribution of patients’ ages and genders is shown in Fig. 3. The types and number of procedures being carried out were

• (a) endodontics (n = 36),
• (b) plastic restorations (amalgam and composite) (n = 70).

Amongst this group of patients, 12 (11%) had found RD pleasant, 71 (67%) comfortable, whilst 22 (21%) felt it was uncomfortable, and1 (1%) found it painful. When asked whet her they would prefer RD to be used at their next appointment, 74 (70%) said yes, 4 (4%) said no, with 28 (26%) expressing no preference.
The data was further analyzed to assess whether there were any significant associations between experience or preference and a number of factors.

Figure 2. Distribution of student patients (SP) by age and sex.



Figure 3. Distribution of dentist patients (DP) by age and sex.

Age.
Respondents were grouped into three age categories,

• (a) 40 years and below,
• (b) 41-60 years and
• (c) over 60 years.

The numbers of respondents in each category for each patient group were:

Group SP:

• (a) 25 (10 females, 15 males);
• (b) 41 (21 females, 20 males);
• (c) 34 (17 females, 17 males).

Group DP:

• (a) 40 (25 females, 15 males);
• (b) 50 (32 females, 18 males);
• (c) 16 (7 females, 9 males).

There was little difference between the percentage of respondents in each age category who preferred no RD next time within either group (SP: 12-15%; DP: 2-6%). As the age category increased, there was a decrease in the percentage of patients who expressed no preference, and an increase in the percentage of those who would wish RD used next time (Table 1). However, use of w2-test showed no statistically significant association between age group and preference for RD use at the next visit for either patient group.

Table 1. The preference expressed for use of rubber dam at the next visit amongst the different age categories of respondents.

Gender.
In both patient groups, half of the male patients expressed no preference for RD use at the next visit whilst the greatest percentage of female patients positively preferred its use. This difference in percentages between the yes and the no preference groups was small (P = 0.37) amongst the student patients but was statistically significant for the dentists’patients (P < 0.01) with a significantly greater percentage of females indicating preference for rubber dam than males. For both male and female respondents, there was a much greater percentage who answered that they would prefer RD compared to those who would not prefer RD use at the next visit (Table 2).

Table 2. The preference expressed for use of rubber dam at the next visit between the sexes in each patient group.

Explanation.
Only four of the student patients and three of the dentist patients did not have the reasons for RD use explained to them, therefore no analysis of this factor which might have modified patient responses was possible. When asked for whose benet respondents felt it (RD) was being used- patient, dentist or both, 76% of SP, and 68% of DP selected- for both, 22% SP, 25% DP- for the patient, and only 4% SP, 8% DP- for the dentist.

Previous Experience.
Twenty-nine student patients and 56 dentist patients had no previous experience of RD use. Of the remainder, in group SP, 28 (39%) found the current experience better, 2 (3%) felt it was worse, and the majority, 41 (58%), judged the experience to have been the same. In group DP, 20 (40%) found the current experience better, 2 (4%) felt it was worse, and the majority, 28 (56%), judged the experience to have been the same.

Current experience.
Patients ranked their current experience of RD as either

• (I) pleasant (6),
• (II) comfortable (52),
• (III) uncomfortable (40) or
• (IV) painful (2).

To enable comparisons across current experience it was necessary to pool categories I and II into a ‘positive experience’group, and III and IV into a‘negative experience’group. As would be expected, the majority of respondents who had had a positive current experience reported that they would prefer RD to be used next time. The majority of those with a negative current experience expressed no preference, with only 31% of SP and 13% of DP preferring no rubber dam next time. Perhaps surprisingly, over one-third of DP and one-quarter of SP who hadhad a negative current experience still indicated that they would prefer to have RD used at their next visit. The w2-test shows a statistically significant association between preference for RD use next time and current positive experience of RD for both groups (P < 0.001). These trends were also seen both in those who had, and in those who had not had previous experience of RD, with the exception that a greater percentage of those with a negative first-time experience of RD expressed a preference for no RD next time (Table 3).

Table 3. The preference expressed for use of rubber dam at the next visit in relation to the patient's current experience of rubber dam for each patient group.

Time taken to apply.
The mean time taken by students to apply RD for all procedures was 4.65 min (SD 4.39) with a range of 1- 30 min and a mode of1min. For the four dentists, mean application time was 1.27 min (SD 1.03) with a range of 0.25-8 min and a mode of1 min. There was no difference in mean application times for either endodontic treatment or placement of restorations within each group. When compared with the patients’experience of rubber dam, there was no statistically significant difference between the mean application time for those who reportede ither a positive or a negative experience (SP, P = 0.58; DP, P = 0.43). The application times were also grouped in to short (<2 min), medium (2-5 min), and long application times (>5 min) (Table 4).The majority, 58%of SP experienced medium application times, whilst 76% of DP had short application times. No statistically significant association was found between application time and experience of rubber dam (SP, P = 0.99; DP, P = 0.75). Application time was also compared with the patients’preference for RD use next time. No statistically significant difference was found between the mean application times of each of the three preference categories (SP, P = 0.34; DP, P = 0.39). Using the application time categories above, there was no significant association between short, medium or long application times and the patient’s expressed preference for future RD use (SP, P = 0.45; DP, P = 0.47).

Table 4. The preference expressed for use of rubber dam at the next visit in relation to the time taken for its application for each patient group.

Duration of use.
The mean duration of RD use for all procedures by SP was 76.25 min (SD 36.57, range 15-180, mode 60 min) and for DP was 27.7 min (SD 13.38, range 2-70, mode 30 min). The mean duration time was longer for those from both groups who reported a negative current experience, but this did not reach statistical significance in either group (P = 0.07). Time durations were grouped, as with application times, into short (<45 min), medium (45-105 min) and long (>105 min) periods. Statistically, a significantly greater percentage of respondents in SP with short duration times reported a positive experience compared with those in the long-duration group (P < 0.01). In the medium-duration group, a greater percentage of positive experience was also reported compared with the long-duration group, but this did not reach statistical significance. Amongst DP, 82% experienced short duration times, with none having a duration over 70 min, so further analysis for DP in relation to duration would not have been meaningful.
Relating time duration preference for RD next time, no statistically significant difference was found amongst the mean duration times of the three preference categories (SP, P = 0.72; DP, P = 0.29). When preference was compared across the three time periods, no statistically significant association was found between duration of RD use and preference for its use in future (SP, P = 0.23; DP, P = 0.34).

Operator.
As might be expected, the mean application time and duration of RD was shorter for the experienced dentists than for the students. Students on average took 3.5times as long to apply dam compared to the dentists. The mean duration for students was over 1 h and just under 30 min for the dentists. Two-sample t-tests confirmed a statistically significant difference between the students and the dentists for both application time and duration (P < 0.01). A significantly greater percentage of dentists’ patients than student patients reported a positive current experience of RD and agreater preference for RD use at the next visit. There was also a significantly greater percentage of students’ patients who would not want rubber dam at the next visit than amongst the dentists’patients (P < 0.01for both).

The method used to gather this information was designed to allow more candid responses than may have been achieved in the similar surveys already referred to (Jones & Reid1988, Gergely1989).This survey enables the opinions of many patients to be assessed, and compares experienced and inexperienced operators. It is clear that only a small number amongst either patient group surveyed actively did not wish to have RD used for future appointments. Whilst this shows that there are patients who do not like RD, as has been asserted (Marshall & Page 1990), it also demonstrates that the majority are not negative towards RD, and indeed many like it and want it to be used.
No clear association could be established between most of the factors assessed and either the patients’ judgement of the experience of rubber dam use, or their preference for its use in future. A greater proportion of males than females did not express any preference for RD use next time, but no statistically significant difference could be seen between the sexes regarding their preference. As the age group of patients increased, the proportion of respondents who did not want RD to be used was very similar, whilst the percentage of those who would want RD used increased and the percentage of those without a preference decreased. No patients who reported a positive experience of RD use were against its use in future; however, some who had a negative experience still wished to have RD used again. There was a suggestion that increased duration of RD influenced the patient’s opinion of their experience, but not their preference for future use.
It would appear that there are few factors related to the patients or the procedure that may be used to predict a patient’s preference for or against RD. The experience of the dentist and by inference their level of skill does influence the patient’s opinion. The best way to improve patient acceptance of RD is for clinicians to use it frequently and thereby become proficient. They should also be aware of patients’ concerns. A few patients entered their comments on their experience of RD. Positive comments included the absence of debris in the mouth or passing into the throat, and protection of the tongue. Negative comments referred to dribbling, being unable to swallow, and having an increase in saliva. For two patients, the clamps had proved uncomfortable. Such complaints may be addressed by careful technique, specifically by ensuring saliva ejectors are efficient, clamps are placed carefully and that local analgesia is adequate. For some patients, their acceptance of rubber dam may be improved by limiting the time for which it is used. The effect of this may have improved patient acceptance, but could not be evaluated here. By adopting a positive approach to RD, the dentist may engender a positive attitude in the patient (Gergely1989).
This investigation found few of the associations reported by Gergely (1989) but is in agreement with his general finding that acceptance of RD is good. In comparison with Gergely’s figures, amongst the dentists patients surveyed here, a similar percentage preferred its use, a higher percentage expressed no preference, but fewer did not wish it to be used in future. There were fewer student patients who preferred RD use, and more who either did not wish it used or expressed no preference. This information will hopefully help to dispel the widely held belief that patients generally do not like rubber dam, and encourage more frequent use of this valuable procedure. Another quoted obstacle to using rubber dam is the time taken to place it. In the hands of most students and experienced dentists, placement took only between 1 and 2 min. Further work is needed to overcome the other reported obstacle, namely dentists’ lack of skill and difficulty in placing dam.

References.

British Endodontic Society (1983) A survey of endodontics in general practice in England. British Dental Journal 154, 222-4.
European Society of Endodontology (1994) Consensus report of the European Society of Endodontology on quality guidelines for endodontic treatment. International Endodontic Journal 27, 115-24.
Gergely EJ (1989) Rubber dam acceptance. British Dental Journal 167, 249-52.
Jones C, Reid J (1988) Patient and operator attitudes toward rubber dam. Journal of Dentistry for Children 55, 452-4.
MarshallK, Page J (1990) The use of rubber dam in the UK: a survey. British Dental Journal169, 286-91.
Reuter JE (1983) The isolation of teeth and the protection of the patient during endodontic treatment. International Endodontic Journal16, 173-81.