Attitudes of Victorian dentists to removable partial denture prosthodontics: treatment planning D. A. S. Parker, MDSc, PhD, FRACDS* J. K. Harcourt, DDSc, FRACDS, FICDt N. H. Cheung, DMD, BScDent(Hons)*

Key words: General dental practitioner attitudes, prosthodontics, treatment planning.

Abstract A survey of the attitudes of dentists in Victoria to various aspects of the treatment planning phase of removable partial denture prosthodontics was undertaken. Data were analysed and compared with those obtained from an identical study in South Australia. Those Victorian dentists who graduated in the 1960% those who worked in multiple- practitioner practices, or non-rural areas, and those who had an added interest in removable prostho- dontics were more likely to stress the importance of a greater number of attributes than those who graduated in the 1950s or 1970% or those who worked alone, in rural areas, or had no particular interest in the discipline. Results indicated also that Victorian dentists tended to place greater emphasis on many of the concepts embraced by the questions asked than their interstate colleagues.

It is suggested that, in addition to formal educa- tion , intraprofessional relationships and interest in a discipline are factors which might influence the concepts and attitudes of general practitioners.

(Received for publication October 1987. Accepted April 1988.)

*Department of Dentistry, The University of Adelaide. tSchool of Dental Science, The University of Melbourne.

Introduction In 1981 a survey of South Australian dentists was

undertaken to determine their attitudes to various aspects of the treatment of patients requiring remov- able partial dentures.'.* It was apparent from this survey that dentists in general practice appreciated the importance of many aspects of the examination and treatment planning phases for such patients and had attitudes which were in accord with the current teaching concepts at the Adelaide Dental School. However, there were aspects in which such atti- tudes were at variance with those taught, especially among those who were not recent graduates or who worked alone.

In order to compare the attitudes and concepts of Melbourne and Adelaide graduates an identical survey was conducted in Victoria in 1984. As in the South Australian study, data were analysed in various ways to determine which factors, if any, could be identified as influencing the responses of the practitioners involved. In this paper the findings of the survey relating to treatment planning are presented.

Methods A questionnaire, identical with that used for the

South Australian study except for reference to loca- tions, was prepared. The questionnaire contained over 200 questions designed to elicit the attitudes and concepts of practitioners to various phases of removable partial denture prosthodontics and was divided into nine parts. Those questions reported in this paper sought information about the type and location of respondents' practices, when they gradu- ated, and their attitudes to history-taking, including

536 Australian Dental Journal 1989;34(6):536-47.

assessment of patients’ attitudes, examination of oral tissues and prostheses and treatment planning. Generally, respondents were asked to indicate the level of importance they attached to a particular concept based on a five-point scale ranging from ‘extremely important’ to ‘of no importance’.

Dentists who were asked to participate in this study were selected at random from the Victorian Dentists Register (1984) after the names of those who were known to be in specialist practice, employed by Government or the University of Melbourne, possessed an initial interstate or overseas qualifi- cation or graduated prior to 1950 or after 1979 were eliminated. Of the 400 dentists to whom the ques- tionnaire was mailed, 210 replies were received by the due date and of these 180 satisfied the criteria for acceptance in the survey, namely, that they:

1. Possessed the degree of Bachelor of Dental Science from The University of Melbourne.

2. Practised removable partial denture prosthodontics.

3. Graduated between 1950 and 1979, inclusive. 4. Practised in private general practice. Responses from those dentists who met the

criteria were coded for analysis by the Statistical Package for the Social Sciences (SPSSX).’ The frequency distributions of responses were deter- mined for individual questions and for several combinations of questions and analysed according to the decades in which dentists graduated, whether their practices were within a 30 km radius of the General Post Office (GPO) or not, whether they were in solo or partnership/associateship type prac- tices and whether they had a particular interest in removable prosthodontics. Dentists were assigned to this latter group if they had tutored prostho- dontics at the University of Melbourne and/or indicated that they had a particular interest in complete or removable partial denture prostho- dontics.

The Chi-squared test was used to determine the level of significance between groups of data; a prob- ability level of P < 0.05 indicated a statistically significant difference.

Results 1. Personal characteristics (a) Decade of graduation

Thirty-nine respondents graduated in the 1950s (that is, 1950 to 1959, inclusive), 50 in the 1960s and 77 in the 1970s. Fourteen practitioners failed to respond to this question.

1950s

0 .... City

Solo

1 Yes

All respondents

I Decade

1960s

Location

I I Suburban Non-rural

Type of practice

..- .. . .. . .*

..- .. . .. . .. ..- .. . .. . .. ..- .. 0 . .. . ..

Partner Principal

Prosthodontic interest

Key to graphs

(b) Location of practice Twenty-one dentists practised in the City of

Melbourne, 118 in the suburbs and 39 in rural areas (that is, outside the 03 telephone zone, within a radius of approximately 30 km of the GPO). Two practitioners failed to respond to this question. Figure 1A indicates the distribution of practices according to the decade of graduation. The percen- tages of graduates from the 1960s and 1970s in each of these locations were similar. However, relatively more graduates from the 1950s practised

Australian Dental Journal 1989;34:6. 537

6o r A Table 1. Respondents’ interests in the major disciplines of dental practice

L

* 0

z n

40

30

5 2

20

10

.. U 1950s 1960s 1970s

Decade of graduation

Fig. 1. -Locations (A) and types (B) of practices according to the decade in which dentists graduated. Refer to key to graphs.

in rural and city areas and fewer in the suburbs. Chi-squared tests indicated that fewer graduates from the 1950s practised in the suburbs and more in the rural areas when compared with the number who graduated in each of the next two decades (Chi- squared, P < 0.05).

(c) TVpe of practice More dentists worked in solo (74) compared with

partnershiplassociateship type (66) practices in this study and, as noted in Fig. lB, relatively more dentists from the 1950s were in solo practices compared with their younger colleagues, whereas

Decade of graduation All Interest respondents 1950s 1960s 1970s

Conservative dentistry Complete denture prosthodontics Partial denture prosthodontics Crown and bridge prosthodontics Endodontics Preventive dentistry Periodontics Other*

67

8

6

23 27 22

7 21

77 56 70

15 8 4

8 6 4

23 26 18 23 28 29

3 30 26 3 8 8

18 14 26

*Includes oral surgery, orthodontics and paedodontics. Figures represent the percentages of dentists who indicated an interest in the particular discipline. Respondents were asked to nominate up to two interests.

more dentists from the later decades were principals in practices which employed assistants or were assis- tants themselves.

(d) Disciplines of special interest As indicated in Table 1, respondents were asked

to indicate whether they had an interest in partic- ular fields of dentistry. Each respondent was asked to select up to two of the fields nominated. Sixty- seven per cent of responses included conservative dentistry, but only 6 per cent removable partial denture prosthodontics. When analysed according to the decade of graduation, relatively more graduates from the 1950s included removable prosthodontics than their colleagues from the later decades and fewer included preventive dentistry.

2. History and examination phases (a) Medical, social and dietary history

The levels of importance placed by the dentists on the four questions asked relating to the need for medical and social histories, consulting patients’ physicians and assessing dietary habits are shown in Table 2. The percentages of people who responded ‘extremely or very important’ to each question were analysed according to the decade in which they graduated, whether they practised in rural or non-rural areas and in solo or partner- shiplassociateship type practices and whether they indicated they had a particular interest in remov- able prosthodontics (Fig. 2). Twenty-nine dentists who indicated an interest in complete or removable partial denture prosthodontics (Table 1) or who had tutored in removable prosthodontics were assigned

538 Australian Dental Journal 1989;34:6.

Table 2. Importance of history and examination phases of treatment planning Extremely or Moderately Little or no

very important important importance

Written summary of medical history 27 43 30 Summary of social and family history 8 40 52 Consultation with physician if patient has medical problem 49 34 17 Assessment of patients’ oral hygiene habits 98 2 0 Assessment of patients’ dietary habits 62 34 3 Assessment of patients’ attitudes to retention of remaining natural teeth 96 4 0 Assessment of patients’ attitudes to dentures 91 9 0 Assessment of periodontal status 98 2 0 Assessment of pulpal status of remaining teeth 81 17 2 Analysis of occlusion 84 15 1 Assessment of bone resorption in edentulous areas 55 39 6 Assessment of old prosthesis if present 55 37 8 Radiographic records 58 33 8

Articulation of study casts 54 32 13 Surveying of study casts 60 25 15

Figures represent the percentages of dentists who responded in each category of importance.

Study casts 64 27 9

to the latter group. For purposes of this report responses of ‘extremely or very important’ will be designated as positive and are coincident with those of the authors.

With two exceptions there were no statistically significant differences between the percentages of responses for any of the groups analysed. The exceptions were that significantly fewer dentists from the 1950s believed it was important to record a written medical history compared with those from the 1960s (Chi-squared, P < 0.05) and significantly more dentists in partnership-type practices believe it was important to consult a physician if a patient presented with a medical problem (Chi-squared, P < 0.05).

There was a tendency for higher percentages of dentists in partnership-type practices and those in non-rural areas to respond ‘extremely or very impor- tant’ to the two questions relating to medical history and consulting a physician.

(b) Assessment of patients’ attitudes In excess of 90 per cent of dentists stressed the

importance of assessing the attitudes of patients to the retention of their remaining teeth and to dentures (Table 2). There were no differences between the percentages of responses for any of the variables tested (Fig. 3).

(c) Oral and denture examination As indicated in Table 2, six questions were asked

in the survey concerning dentists’ perceptions of the importance of assessing various aspects of oral health and function. More than 90 per cent stressed the importance of assessing oral hygiene habits and

periodontal status, 81 per cent emphasized the importance of assessing the pulpal status of remaining natural teeth, and 84 per cent indicated that occlusal analysis was at least ‘very important’. However, only 55 per cent responded positively to the questions relating to assessment of bone resorp- tion and existing prostheses.

When these questions were analysed according to the four variables shown in Fig. 3 and 4, there were few differences between the attitudes of dentists in the various groups. It was noticeable that more graduates from the 1960s and those assigned to the interest in prosthodontics group placed greater importance on assessing bone resorption and existing prostheses than dentists who graduated at other times or who did not meet the criteria relating to interest in prosthodontics. Chi-squared analyses indicated that significantly more graduates from the 1960s (P < 0.05) and those in partnership-type prac- tices (P < 0.05) stressed the importance of assessing bone resorption.

(d) Radiographs and study casts In addition to the question listed in Table 2

relating to the importance of radiographic records, dentists were asked which radiographs they ‘usually required’ for patients for whom they were to construct removable partial dentures. Nine per cent nominated orthopantomographs, 77 per cent regional periapicals, 62 per cent bitewings, and 3 per cent full mouth surveys.

Those dentists who graduated in the 1950s and 1960s and those in non-rural areas or who had an interest in removable prosthodontics were more likely to require regional periapical radiographs

Australian Dental Journal 1989;34:6 539

v)

C 0

2 % E c 0 9) 0) m C 9)

9)

- 2 a

100

50

0

A B

50

0 a b C d e a b C d e

Fig. 2. -Percentage of dentists who responded ‘extremely or very important’ (positively) to questions concerning written summaries of patients’ medical histories (A); social and family histories (B); consultations with medical practitioners (C); and dietary histories (D). Each question was analysed according to the responses from all respondents (a), and from dentists in each decade (b), in urban or rural practices (c), in solo or partnership-type practices (d), and with an interest in, or no specific interest in, removable prosthodontics

(e). Refer to key to graphs.

Table 3. Importance of aspects of treatment planning phase Extremely or Moderately Little or no

very important important importance

Written treatment plan Discussion of treatment with patient Detailed diagram of RPD design Provision of temporary RPD if treatment prolonged Stabilization of healthy periodontal condition+ Endodontic treatment of abutment teeth‘ Completion of all restorations‘ Completion of only those restorations related to the RPD+ Instruction in oral hygiene Denture to be left out of mouth at night Regular recall visits

‘Before construction of RPD (removable partial denture). tRounding errors makes total percentage greater than 100. Figures represent the percentages of responses from dentists for each question asked.

30 91 54 25 90 85 84 63 96 49 66

35 9

29 41 10 10 13 8 4

30 24

35 0

17 34

I t 5 3

29 0

21 10

540 Australian Dental Journal 1989;34:6.

100

50

C

100

50

0

A

C

a b C d e

B

D

a b C d e Fig. 3. -Percentage of practitioners who responded positively to questions concerning the importance of assessing patients’ attitudes to the retention of remaining natural teeth (A) and to their dentures (B); assessing oral hygiene habits (C); and existing prostheses

(D). Each question was analysed according to the responses from all respondents (a), and for the four variables as in Fig. 2. Refer to key to graphs.

(Fig. 5). Chi-squared analyses indicated that signifi- cantly more graduates from the 1950s and 1960s (P c 0.05) and non-rural practices (P < 0.02) ’usually required’ regional periapical radiographs when compared with graduates from the 1970s and rural practices, respectively.

Although 64 per cent of respondents stressed the importance of obtaining study models for patients, only 37 per cent felt that it was at least ‘very irnpor- tant’ to obtain articulated and surveyed study models for those patients who required partial dentures (Table 2 and Fig. 5). Graduates from the 1960s, those in city or suburban and partnership- type practices and those with an interest in remov-

able prosthodontics were more likely to stress the need for articulated and surveyed study casts (Fig. 5). However, none of these trends was statistically significant except that more dentists in partnership- type practices stressed the importance of obtaining study-casts (Chi-squared, P C 0.01).

3. Treatment planning phase Table 3 summarizes the questions asked relating

to the treatment planning phase and the level of importance assigned to each question by respon- dents. Questions relating to the discussion of treatment plans with patients, the need to complete various aspects of mouth preparation prior to the

Australian Dental Journal 1989;34:6. 541

100

50

0

100

50

0

A

C

a b C d e

B

a b C d e

Fig. 4. -Percentage of practitioners who responded positively to questions concerning the importance of assessing the periodontal (A) and the pulpal status of patients’ natural teeth (B); the resorption of bone in the edentulous areas (C); and the nature of patients’ occlusions (D). Each question was analysed according to the responses from all respondents (a), and for the four variables as in Fig.

2. Refer to key to graphs.

construction of partial dentures and the need for oral hygiene instruction were seen by most to be ‘extremely or very important’. Considerably less importance was placed on other aspects of treatment planning. Results of the analyses by the four vari- ables, decade of graduation, site and type of practice and interest in prosthodontics, are presented in Fig. 6 and 7. It should be noted that the questions relating to mouth preparation were grouped-by ascertaining the percentage of positive responses to both the questions regarding periodontal and endodontic therapy and for either or both questions relating to the completion of restorations. As shown

in Fig. 7,75 per cent of dentists stressed the impor- tance of creating a mouth in which the periodontal health was stable and endodontic therapy and conservation of at least the abutment teeth were completed prior to the construction of partial dentures. Dentists who graduated in the 1960s were most likely to stress the importance of written treat- ment plans (1960s graduates compared with 1 9 5 0 ~ ~ Chi-squared, P < 0.05), diagrams of partial denture designs and the provision of temporary partial dentures, while those in partnership-type practices were more likely to respond positively to the latter two questions (Chi-squared, P < 0.05).

542 Australian Dental Journal 1989;34:6.

100

50

0

100

50

0

A

C

m

a b C d e

B

D

a b C d e

Fig. 5. -Percentage of practitioners who responded positively to questions concerning the use of regional periapical (A) and bitewing (B) radiographs; and the importance of study casts (C); and articulated and surveyed study casts (D). Each question was analysed

according to the responses from all respondents (a), and for the four variables as in Fig. 2. Refer to key to graphs.

Discussion The purposes of this study were to collect and

analyse data from dentists in general practice in the State of Victoria regarding their attitudes to the importance of various aspects of removable partial denture prosthodontics and to determine whether characteristics such as the decade in which dentists graduated or the type or location of their practices influenced these attitudes. As Parker et al.' have reported recently on the findings of an identical survey in South Australia, it was of interest to compare the two sets of data, especially as their findings implied that there were differences in the

attitudes of more recent graduates and those who practised in partnership/associate-type arrange- ments.

1. Characteristics of respondents As a consequence of the experience of the South

Australian survey, the number of dentists asked to participate in the present study was increased in the expectation that the number of respondents in the smaller groups, such as those in rural practices, would be increased. However, no attempt was made to standardize the sizes of the various groups. Although the number of dentists whose responses

Australian Dental Journal 1989;34:6 543

A 100

50

0

100

50

a

C

a b C d e

D

a b C d e Fig. 6. -Percentage of practitioners who responded positively to questions concerning the importance of compiling written treatment plans (A); detailed diagrams of partial denture designs selected (B); discussing treatment plans with patients (C); and providing a regular recall service (D). Each question was analysed according to the responses from all respondents (a), and for the four variables as in

Fig. 2. Refer to key to graphs.

were analysed in this study was greater than in the South Australian survey (180 compared with 98), fewer practised in the City of Melbourne compared with those practising in the City of Adelaide and the number with an interest or added experience in removable prosthodontics was almost identical. Whilst the number of respondents in the Victorian survey who graduated in the 1970s was greater, there were relatively fewer graduates from this decade than in the South Australian study.

As in South Australia, the majority of Victorian respondents practised in the suburban areas, however, there were relatively more practitioners in rural areas in Victoria (22 per cent compared with 12 per cent), and fewer in the city (12 per cent

compared with 26 per cent). These results can be explained on the basis of the distributions of the populations in the two States and on the relative sizes and functions of the inner (city) areas of the two capital cities. No explanation can be offered for the greater number of dentists in solo practice in Victoria (41 per cent) compared with South Australia (27 per cent). In their previous paper, Parker and co-workers suggested that graduates from the 1960s were more likely to be in solo prac- tice and less likely to be in country areas than graduates from the other two decades and proposed that this might reflect changes in the demands for dental services and the ease with which graduates of the time might have established new practices

544 Australian Dental Journal 1989;34:6.

100

50

0

1 00

50

0

A

C

a b C d e

B

D

a b C d e

Fig. 7. -Percentage of practitioners who responded positively to questions concerning the importance of the provision of temporary partial dentures (A); instruction in oral hygiene (B); the completion of mouth preparation procedures (namely, stabilization of healthy periodontal conditions, endodontic therapies and related restorations) prior to the construction of partial dentures (C); and removing dentures from the mouth at night (D). Each question was analysed according to the responses from all respondents (a), and for the

four variables as in Fig. 2. Refer to key to graphs.

in urban areas. This argument is supported in part by the present results in which graduates from the 1960s were less likely to be in rural practices than their colleagues, but is not supported by the finding that they were less likely to practice alone than those who graduated in the 1950s.

As in the previous study, Victorian dentists most frequently included conservative dentistry as one of the two disciplines of dentistry of interest to them, but considerably fewer included removable prosthodontics and, in particular, complete denture prosthodontics. In the South Australian study the

most noticeable features of this aspect of the survey were the decreased levels of interest in complete and removable prosthodontics shown by graduates in the 1960s and 1970s relative to the 1950s and the increased interest in crown and bridge prostho- dontics. In Victoria there were few changes in the interests of graduates between each of the decades. As a consequence of the small numbers who included removable complete or partial denture prosthodontics as an interest or who had tutored removable prosthodontics (1 3), the number who hlfilled the criteria for inclusion in the group desig- nated ‘interest in prosthodontics’ was small (29 or

Australian Dental Journal 1989:34:6. 545

16 per cent) even in comparison with the South Australian study (27 or 28 per cent).

2. Attitudes of respondents Results of the survey indicated that, like their

South Australian colleagues, Victorian dentists placed different emphases on various aspects of the history, examination and treatment planning phases of removable partial denture prosthodontics. Most dentists agreed that assessing patients’ attitudes, habits, periodontal health, occlusion and the endodontic status of remaining teeth and discussing treatment plans with patients were at least ‘very important’. However, relatively few agreed that it was important to record written medical histories and treatment plans and to obtain articulated and surveyed study casts and only approximately one in two responded positively to those questions concerning consultation with physicians, assess- ment of existing dentures and bone resorption, preparing diagrams of denture designs and the non- use of dentures at night. As the last four questions relate to attitudes which are specific to partial denture prosthodontics, it is of concern that at least 45 per cent of respondents apparently believe that it is not important to assess bone resorption and existing dentures before constructing a prosthesis, or of advising patients of the need to remove partial dentures at night.

Comparison of the results of this survey with those from the previously reported South Australian study indicated that a higher percentage of Victorian dentists responded positively to more questions than their interstate colleagues. Thus, if an increase of 10 per cent in the percentage of posi- tive responses is taken as reflecting differences in attitudes, Victorian dentists were more likely to stress the importance of nine questions, South Australians four questions, and for 11 questions the difference was less than 10 per cent. Of particular interest was the trend for Victorian practitioners to emphasize the importance of assessing existing dentures, the status of remaining teeth, bone resorp- tion, regional periapical radiographs and articulated and surveyed study casts, whereas more South Australians emphasized the non-use of dentures at night, the need for recall visits and detailed diagrams of partial denture designs. To what extent the teaching and research activities in the relevant departments in the two universities influenced these attitudes is difficult to determine, but as one of the major research activities in the Department of Dental Prosthetics of the University of Melbourne during the 1960s and early 1970s concerned bone metabolism4.’ it is conceivable that this work

influenced the attitudes of those who graduated in this period. Although not documented, it is suggested that the emphasis on recall visits and the formal requirements for approved partial denture designs for patients treated by students in the University of Adelaide was greater than that in Melbourne.

Analysis of the 24 questions, or combinations of questions, relating to the present report by the four variables tested also revealed some interesting differ- ences. However, it must be emphasized that for some questions, namely, those relating to social history and to a lesser extent medical history, written treatment plans and the provision of temporary dentures, the number of positive responses was small and thus care needs to be exer- cised in interpreting results. Nevertheless, the results of this study imply that graduates from the 1960s, those in urban or partnership-type practices and those who indicated an interest in or had added experience through tutoring removable prostho- dontics tended to respond positively more frequently to a greater number of questions than those who graduated in the other decades, did not have an interest in or added experience in prosthodontics or who practised in rural or solo practices. These results paralleled the South Australian study in that those who practised in part- nershiplassociateship arrangements were more likely to provide positive responses, but differed in that more graduates from the 1960s rather than 1970s responded positively to a greater number of questions. As the rural group in the South Australian study was very small, comparisons are difficult, however, comparison of the response rates from those with an interest in prosthodontics compared with those with no specific interest tended to be distinguishable in the Victorian but not the South Australian study.

A hrther indication of the differences in attitudes between respondents in the two states can be seen when the 10 per cent differential explained above was applied to all but one question for each of the four variables. The question not included related to summarizing a social and family history, as so few responded positively. Consideration of the responses from those who graduated in the 1950s indicated that for nine questions more Victorian dentists stressed the importance of the concept, while for only two questions did the percentage of positive responses from the South Australians exceed their colleagues. For graduates from the 1960s this ratio was 12:1, whereas for those who graduated in the 1970s the ratio was reversed (3:6). Such changes are supportive of the contention

546 Australian Dental Journal 1989;34:6.

expressed previously that graduates from the 1960s in Victoria and those from the 1970s in South Australia possessed attitudes which were more frequently aligned with those of the authors. As the rural group in South Australia was small such a comparison was not considered to be meaningful; however, comparisons of the responses from those in the urban groups indicated that for 11 questions the percentages of positive responses from Victorian dentists exceeded those from the South Australians, while for three questions the position was reversed. Of the remaining variables, those Victorian dentists in solo or partnership-type practices and those with or without an interest in prosthodontics tended to respond positively to a greater number of questions than their South Australian counterparts - 10:5, 8:2, 12:3 and 53, respectively.

In summary, it appeared that whereas in the South Australian study Parker et al.’ reported that the most recent group of graduates and those in partnership-type practices possessed attitudes which were closer to their own and those taught in the University of Adelaide, the present study indicates that graduates from the 1960s, those in partnership or with an interest in prosthodontics were more likely to have concepts co-incident with those accepted as being positive for purposes of the analysis. Victorian dentists in all groups, except that represented by graduates from the 1970s, tended to stress the importance of a greater number of ques- tions asked than their South Australian colleagues. This study further strengthens the findings of the earlier study that there are various aspects of the examination and treatment planning phases of removable partial denture prosthodontics which are widely acknowledged by general practitioners to be at least ‘very important’, but highlights areas in which it is suggested that the views of many educators and practitioners are at variance. The

survey has not established why so many practi- tioners placed a low level of importance on written treatment plans, associated denture designs and medical histories, and why consultations with physi- cians, assessing bone resorption and existing dentures, preparing articulated and surveyed study casts, and advising patients about the use of dentures are seen as no more than ‘moderately important’ by so many. Whatever the reason, it is suggested that there is a need for many of the basic principles of removable prosthodontics to be more widely disseminated within the profession, espe- cially amongst those who do not appear to have close intra-professional relationships.

Acknowledgements The authors wish to thank Drs L. C. Richards

and D. R. Brown, and Messrs D. A. Webster and D. A. Nutting for their assistance in analysing the data.

References 1. Parker DAS, Cheung NG, Richards LC. A survey of remov-

able partial denture prosthodontics: attitudes of dentists to treatment planning. Aust Dent J 1987;32:343-53.

2. Cheung NH. Removable partial denture prosthodontics in dental practice: a survey. Adelaide, South Australia: The University of Adelaide, 1984. MDS thesis.

3. Statistical Package for Social Sciences Inc. SPSS’ user’s guide. 2nd edn. Chicago: SPSS Inc., 1986.

4. Johnson K. A three-year study of the dimensional changes occurring in the maxilla following immediate denture treat- ment. Aust Dent J 1967;12:152-9.

5 . Johnson K. A study of the dimensional changes occurring in the maxilla following open face immediate denture treat- ment. Aust Dent J 1977;22:451-4.

Address for correspondenceheprints: Department of Dentistry,

The University of Adelaide, GPO Box 498,

Adelaide, South Australia, 5001.

Australian Dental Journal 1989;34:6. 547