removable partial denture survey: clinical practice today

Removable partial denture survey: Clinical practice today

J. M. Cotmore, D.M.D.,* E. B. Mingledorf, D.D.S.,*+ J. M. Pomerantz, D.D.S.,*** and J. E. Grasso, D.D.S., M.S.**** University of Connecticut, School of Dental Medicine, Farmington, Conn.

A review of removable partial denture research by Cecconi’ broadly covers the field up to the late ’70s, and there is no need to repeat his fine work. However, certain findings must be highlighted because of their significance to this article.

BACKGROUND INFORMATION

Fran@’ showed that the variability in framework design was as great as the number of dentists involved in making the designs, even after they were given specific training in removable partial denture design. He appealed for increased instruction for dentists because of their demonstrated and admitted lack of understanding. Trainor et al.4 concluded that deficiency in rationale for a design for a specific clinical situation was, in part, a function of dentists’ training. They found that dentists significantly improved their performance after taking a postdoctoral-level course in removable partial denture design.

McCracken,s Sykora and Calikkocaoglu,6 and others condemned the practice of dentists having dental laboratories design their removable partial denture frame- works. They claimed that laboratory technicians can- not make valid design decisions without a biologic knowledge of the oral structures. Sykora’ subsequently found that although the teaching at Canadian dental schools was reasonably uniform, there was great variation in the work produced by Canadian commercial dental laboratories. Schwarz and Barsby stressed the difference between what is taught to dentists and the removable partial denture service they deliver once in practice. Their failure to perform basic steps in removable partial denture treatment can lead to unsatisfacto-

*Assistant Professor, Department of Restorative Dentistry. **Professor and Chairman, Department of Fixed Prosthodontics,

Temple Umversiry, School of Dentistry, Philadelphia, Pa. ***Resident, Maxillofacial Clinic, Veterans Administration Medi-

cal Center, Wilmington. Del. ****rlssociate Professor, Department of Restorative Dentistry.

QUESTIONNAIRE (SECTION I)

Group totals A. Year of graduation: A B B. Primary type of practice:

either 1. a. General practice 79 32 b. Prosthodontics I I)

or 2.” a. Endodontics 3 ‘7 b. Oral surgery 4 4 c. Orthodontics I? 15 d. Pedodontics 1 0 e. Periodontics 2 7 f. Public health if a g. Other ..A 3

Total respondents 92 60 Total possible respondents iO2 94

*If you checked any category in No. 2 above. please tl~, YU~! completr section II but return the questionnaire in the ewl,wd envelopv. Thank you.

ry results for which laboratory technicians will be blamed. To determine whether the observed difference between what is taught and what is practiced by dentists was real, the same authors” surveyed the teaching programs of 18 British dental schools. They found a surprising similarity in instruction. Therefore, to explain the difference they examined the fee struc- ture of the National Health Service. They noted that the compensation for removable partial denture treatment was insufficient to provide the necessary clinical and laboratory time, as taught in the dental schools. Dentists consequently used shortcuts in their treatment to survive within the system.

Because of these findings, it was decided to solicit information from practicing dentists on their practical experiences. This was done to establish a baseline of actual practice in a small segment of the American dental population and to find areas of procedural weakness and decreased compliance with dental school education. Such information can be useful in redefining and adapting future courses in removable partial

THE JOURNAL OF PROSTHETIC DENTISTRY 321

COTMORE ET AL

QUESTIONNAIRE (SECTION II)

This section of the questionnaire is designed to determine how practicing dentists provide for the patient who requires a removable partial denture (RPD). Please answer the following questions by checking the appropriate answer.

Total No. of respondents Yes

110 51

% responses* No 19 1. Do you feel that your

instruction in removable partial prosthodontics adequately prepared you for practice and delivery of RPDs to patients?

2. Do you. . . a. make study models

(diagnostic casts) in the office?

b. articulate study models in the office?

c. survey study models in the office?

d. send preliminary impressions to the laboratory?

e. send preliminary models to the laboratory?

f. prepare teeth. . . i. before the preliminary

impression? ii. based on study of the

diagnostic cast? g. prepare teeth with occlusal

and lingual seats? h. prepare teeth with guiding

planes? i. make a final (secondary)

impression . . . i. in a custom tray? ii. in a stock tray?

i make a final impression with. . i. reversible hydrocolloid? ii. irreversible hydrocolloid? iii. rubber base elastomer? iv. silicone elastomer? v. other?

k. pour final impression in the office?

1. send final impression to the laboratory?

Sometimes 30

112 69 4 27

112 26

40(26)

9

41

111

110

39(64)

84

33

21(10)

7

109 34 44 22

103 17 22

110

112

76(72)

89

20(12)

11

111 67

61

4(16)

0

13 20

101 25 37 38 105 56 12 32

86 10 78 12 95 48(67) 26(6) 26(27) 90 15 51 34 85 15 52 33 60 23 50 27

107 75 12 13

102 29 60 11

*Responses are expressed as a percent of the combined groups A and B when the data are found not significant by the chi-square test between groups. When they are significant (p < .05), the groups are shown separately: group A without parentheses and group B within parentheses.

prosthodontics at the predoctoral and postdoctoral The two classes chosen graduated 7 years apart: one levels. in the ’70s (group A) and the other in the ’60s

METHODS (group B).

A questionnaire (pp. 321-323,325) was composed to Alumni from an eastern dental school were chosen elicit as much participation as possible. No attempt was

for the study because they were taught removable made in the questionnaire to bias the respondent to one partial prosthodontics based on different philosophies. philosophy of removable partial denture treatment or

322 MARCH 1983 VOLUME 49 NUMBER 3

REMOVABLE PARTIAL DENTURE SURVEY

QUESTIONNAIRE (SECTION II)--cont’d


% responses* NO Sometimes

m. send written detailed work authorization prescription (instructions) to the laboratory?

n. telephone (verbal) instructions to the laboratory?

o. send. _. i. surveyed master cast to

the laboratory? ii. with framework

outlined? p. ask the laboratory to design

the RPD? q. send opposing model to the

laboratory? r. request return of waxed-up

framework on refractory cast ?

17

106 95 0 5

104 4 51 45

107 35 48

104 63(35) 20( 39)

107 20 52

104 95(79) 4(14)

104 15 78

17(26)

28

l(7)

S. request return of cast framework on master cast?

t. make jaw relation record with occlusion rims?

u. use a face-bow transfer? v. take a protrusive record? w. have a try-in

appointment? x. cut rest seats at insertion

appointment? y. instruct and educate the

patient on use and care of the RPD i. using printed directions? ii. verbally?

2. schedule a postinsertion appointment within . i. one week? ii. one month? iii. three months? iv. six months? V. one year?

12 16 S(l4)

l(0)

103 78 4 18

107 44 21 35

107 8 80 107 16 68 104 86( 65) 9(21)

102 601) 93(79)

101 30 62 8 107 95 1 4

102 76 13 11 75 21 59 20 72 4 79 17 79 49 41 10 71 27 60 13

another, and no substantiation for a procedure was ing “yes, ” “no,” or “sometimes.” Individual preference sought. The aim was simply to generate information for the range of questions was not analyzed because an concerning the current practice of two groups of average opinion was sought. Data are combined for dentists who graduated 7 years apart. Answers were both groups A and B where no significance was found recorded as “yes,” “no,” or “sometimes.” The first by the chi-square test between groups. In those section of the questionnaire categorized the partici- instances where there was a significant difference pants, and the remainder of the questionnaire was between groups A and B (p < .05) by the same test, the divided into two sections to produce information on data are shown for each group, with group B in clinical procedure and framework design. parentheses.

The data are expressed as percents of those answer- Every question was not completed by those respond-


COTMORE ET AL

ing; hence the combined number of respondents of both groups is recorded for each question in questionnaire sections II and III.

RESULTS

Items of particular interest only are noted. The complete results are shown in the questionnaire.

The population

After two mailings of the questionnaire 8 months apart, 90% of the class of the ’70s (group A) responded and 64% of the class of the ’60s (group B).

The distribution of respondents including general practitioners and specialists (section I) shows that of those responding, 86% in group A practiced some removable partial prosthodontics while only 53% in group B did. Group A had fewer specialists, and the most significant specialty within group B was orthodontics (25%). Of those answering section II, therefore, there was a possible combined total of 112 respondents.

Clinical performance

A. Combined groups (section II) 1. Nineteen percent did not feel adequately pre-

pared for removable partial denture practice, and 30% only partially prepared.

2. Most respondents made diagnostic casts, prepared guiding planes, used a stock tray for the final impression, poured the final impression, requested the return of the framework on the master cast, and had a postinsertion appointment after 1 week.

3. Few respondents used rubber base or silicone elastomers for the final impression, made a protrusive record, and gave the patient printed instructions on the use and care of the prosthesis.

4. Almost all respondents prepared occlusal or lingual rest seats, sent a written work authorization to the laboratory, and gave verbal instructions to the patient on the use and care of the prosthesis.

5. Very few respondents used reversible hydrocolloid as the final impression material, and used a face-bow. B. Individual groups (section II)

Significant differences existed between groups in the following procedures:

1. Most of group A surveyed their diagnostic casts when those answering “sometimes” were included, whereas group B generally did not.

2. Most of both groups prepared the teeth based on a study of the diagnostic casts; but, significantly, group A did this to a greater extent than group B.

3. Group B used irreversible hydrocolloid more than group A; but if “sometimes” responses were added to “yes” ones, then almost all used the material for the final impression.

4. Most of group A outlined the framework on the master cast in contrast to group B.

5. Almost all respondents of group A sent the opposing model to the laboratory; yet while most of group B did the same, a significant number did not.

6. Almost all of group A had a try-in appointment as did most of group B, but a significant number of group B did not.

7. Almost no one cut rest seats at the time of denture insertion, except for a few in group B.

Framework design

A. Combined groups (section III) 1. Most respondents used a lingual bar, circumfer-

ential retentive and reciprocal clasp arms, and a mesio-occlusal rest on the distal abutment for distal- extension ridges.

2. Few respondents used an anterior split lingual bar, the altered cast technique for a functional impression of distal-extension ridges, and wrought wire clasps for distal-extension removable partial dentures as a first choice, although half of the respondents sometimes used them.

3. Many respondents used or chose the option to use the rest, proximal plate, and I-bar (RPI) clasp assem- bly, and yet few indicated that they used retention on the center of the buccal surface of the distal abutment in distal-extension ridges. B. Individual groups (section III)

Significant differences existed between the groups in the following procedures:

1. More of group A used a palatal plate major connector on occasion, whereas a majority of group B did not use it.

2. Although significant differences existed between groups on choice of framework design, major trends were seen only if “yes” and “sometimes” answers were combined. From the questionnaire results, more of group A used a U-shaped palatal strap or linguoplate major connector than group B, and less of group A used anterior and posterior palatal strap major connectors and wrought wire retentive clasps than group B.

DISCUSSION

It is the purpose of the discussion to relate the findings of this article and others to the fulfillment of improved curriculum and the practice of removable partial denture prosthodontics.



QUESTIONNAIRE (SECTION 1111

This section of the questionnaire is concerned with RPD framework design. Please mark in the right-hand column your preference for each of the design items listed.

1. Major connectors: a. palatal plate, anatomic replica b. U-shaped (horseshoe) palatal

strap c. single palatal strap d. anterior and posterior palatal

straps e. palatal bar(s) f. lingual bar g. anterior split lingual bar h. linguoplate

2. Retention (clasp arms): a. circumferential (Akers) b. bar (Roach) c. wrought wire

3. Reciprocation (clasp arms): a. circumferential b. bar c. plate d. combined guiding plane and mi-

nor connector 4. Distal extension RPDs:

a. use altered master cast technique b. position of rest seat on most dis-

tal abutments: i. mesio-occlusal ii. disto-occlusal

c. use wrought wire clasps d. use rest, proximal plate, and I-

bar (RPI) clasps e. position of retention on most

distal abutments: 1. mesiobuccal ii. distobuccal iii. center of buccal surface,

mesial to distal


% responses* No Sometimes

101 25(37) 25(43) 50(20) 103 33(36) 9(28) i8(36)

101 15 42 43 101 18(45) 43(24) 39(31)

94 17 46 37 105 73 6 21 95 9 74 17

102 24(21) 20(43) 56(36)

111 67 0 33 109 44 11 45 107 8(24) W7) OO(O?)

106 57 7 36 100 23 33 44 101 24 20 56 109 38 9 53

99

105 100 104 100

95 98 89

5 73 22

65 6 29 32 32 36 7 41 52

38 17 45

42 15 43 42 22 36 11 47 42

*Responses are expressed as a percent of the combined groups A and B when the data are found not significant by the chi-square test between groups. When they are significant (p < .05), the groups are shown separately: group A without parentheses and group B within parentheses.

The fact that half the practicing dentists who sense this can be considered a conditioning of the answered this questionnaire felt that they were trained dentists, for they were educated in a specific environ- inadequately or only for certain aspects of removable ment and were then examined a second time to partial denture treatment confirms opinions expressed determine whether any change had occurred. Although by Frantz3 and Atkinson and Elliott.” The reasons for every attempt was made to remove subjectivity from the this deficiency are not known in detail, but Trainor et clinical assessment, some remained because of the a1.4 showed that additional training in removable nature of the form of the evaluation. Speculation partial denture design significantly helped practicing remains as to the outcome if a different group of dentists gain confidence and proficiency in communi- examiners had measured the final performance. These cating their needs to dental laboratory technicians. In a comments are not .intended to belittle the importance of


training either at the predoctoral or postdoctoral levels but to emphasize that acquiring additional knowledge through training hastens progress to greater achieve- ment. However, a dentist must be adequately compen- sated to render service at a higher level. This does not appear to be the experience of Barsby and Schwarz’ in the United Kingdom. Could this be a factor in the United States? Are some of the inadequacies in practice the result of financial necessity or of insufficient understanding during training? Our results indicated that a significant number of practitioners felt that their training in removable partial prosthodontics was inad- equate. It would be interesting to know if they also felt that their training was weak in other disciplines of dentistry as well.

A significant number of respondents did not survey diagnostic casts, especially in group B. Bowman” showed that most schools in the United States require a surveyor as an item of equipment, and it is unlikely that lack of its use was through unfamiliarity. Quality of design is partly dependent on correct placement of retentive and reciprocal clasp arms in relation to the contours of abutment teeth. In this study the more recent graduates (group A) surveyed diagnostic casts and indicated the framework design on the final cast by a ratio of 2: 1 as compared to group B.

There was appreciable variation between groups in the selection of major connectors and types of clasps. These findings tend to support the contention that one of the weaknesses of removable partial denture treatment rests in the need for further training in the field.‘,4v’0 What is not known is whether the failure is a function of the curriculum, the instruction, or the student.

Procedurally there was significant variation in treatment after the final impression or cast was sent to the laboratory. Most dentists asked for the return of the framework, but only slightly more than half requested occlusion rims. A surprising finding was the number in group B who cut rest seats at insertion. Almost no one used the altered cast technique to try to minimize the problems that develop from tooth- and tissue-borne parts of a bilateral distal-extension removable partial denture.

Should removable partial denture programs be expanded at the predoctoral level, or should participa- tory postdoctoral programs provide this need? The already crowded curriculum and ceaseless demand for inclusion of new material are probably reasons for expanding removable partial denture training at the postdoctoral rather than the predoctoral level. The vital

COTMORE ET AL

interaction between disciplines in the treatment of a patient and the student’s growth from the preclinical introduction to graduation are full enough to provide a basic knowledge. The educator’s hope is that the stimulation to seek other knowledge will not stop at graduation. It is probably true that once practicing, newly graduated dentists will soon find a need to expand their knowledge. The positive effect of recog- nizing needs and then finding sources to satisfy them is perhaps the best mixture for successfully building on the core of knowledge provided in a dental education.

SUMMARY

A survey was conducted of two dental school classes that graduated 7 years apart: group A in the ’70s and group B in the ’60s.

The questions dealt with type of practice, removable partial denture treatment, and framework design.

Results of the survey showed significant differences between the groups in answer to several questions, as well as in general trends in treatment and design.

Discussion centered on the need for improvement in performance and the level at which it should occur.

We especially thank Dr. Jon Goldberg for his advice and help with the analysis of the data; Drs. Henry Muller III, James W. Schweiger, and Ronald E. Zimmerman for their valuable criticism and encouragement; and all those who enthusiastically participated in the survey, without whom this study would not have been possible.

REFERENCES

1.

2.

3.

4.

5.

6.

7.

8.

9.

Cecconi, B. T.: Removable partial denture research and its clinical significance. J PROSTHET DENT 39:203, 1978.

Frantz, W. R.: Variability in dentists’ designs of a removable maxillary partial denture. J PROSTHET DENT 29~172, 1973.

Frantz, W. R.: Variations in a removable maxillary partial denture design by dentists. J PROSTHET DENT 34~625, 1975.

Trainor, J. E., Elliott, Jr., R. W., and Bartlett, S. 0.: Removable partial dentures designed by dentists before and after graduate level instruction: A comparative study. J PROS-

THET DENT 27:509, 1972.

McCracken, W. L.: Survey of partial denture designs by commercial dental laboratories. J PROSTHET DENT 12:1089,

1962.

Sykora, O., and Calikkocaoglu, S.: Maxillary removable partial denture designs by commercial dental laboratories. J PROSTHET DENT 23~633, 1970.

Sykora, 0.: Extracoronal removable partial denture service in Canada. J PROSTHET DENT 39:37, 1978.

Schwarz, W. D., and Barsby, M. J.: Design of partial dentures in dental practice. J Dent 6:166, 1978. Barsby, M. J., and Schwarz, W. D.: A survey of the teaching of partial denture construction in dental schools in the United Kingdom. J Dent 7~1, 1979.



10. Atkinson, R. A., and Elliott, Jr., R. W.: Removable partial dentures designed for laboratory fabrication by recent dental school graduates. A survey. J PROSTHET DENT 22:

429, 1969. 11. Bowman, ,J. F.: Removable partial prosthodontics: Com-

parison surveys-1964 and 1969. J Dent Educ 34:93. 19’0.

ERRATUM

In the article on the American Board of Prosthodontics by Wendt beginning on page 740 of the December 1982 issue

of the JOURNAL, the following names should have appeared with those listed as Dipfomates, 1982:

Thomas J. Rabbi, Upper Dublin Professional Center, 1244 Fort Washington Ave., Fort Washington, PA 19034 ‘I’beodore Berg, UCLA School of Dentistry, Center for Health Sciences, Los Angeles, CA 90024 James S. Brudvik, University of Washington, School of Dentistry, Seattle, WA 98195 Charles R. DuFort, 1543 Mesquite St., Wichita Falls, TX 76302 Robert D. Lytle, 6847 Tulip Hill Terrace, Bethesda, MD 20816 J. A. McKinnon, Jr., 4417 Tidewater Dr., Orlando, FL 32806

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removable partial denture survey: clinical practice today

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