- Email: [email protected]
Determination of demand for posterior resin restorations
27. 28.
29.
Penny R. Aids to the laboratory diagnosis of AIDS. Pathology 1984;16:375. Centers for Interdisciplinary Research in Immunology and Diseases at UCLA. AIDS: reference guide for medical professionals. Los Angeles, Calif: UCLA School of Medicine, 1984. Wilkins EGL, et al. Difficulties in the diagnosis of acquired immune deficiency syndrome. Am J Clin Path01 1984;37:1316.
Reprint requests to: DR. FREDRIC A. MOORE 10~~ MEDICAL DETACHMENT (DS) CAMP CASEY,KOREA APO SAN FRANCI~~, CA 96224
titis B, AIDS, and Herpes in Dent&y can be obtained free of charge by writing to Centers for Disease Control, Center for Preventive Services, Dental Disease Prevention Activity, Atlanta, GA 30333. A beneficial guide that outlines many of the basics of AIDS is entitled AIDS: Reference Guide for Medical Professionals, and can be obtained by sending $3.50 to CIRID/Outreach and Education, c/o Dept. of Microbiology and Immunology, UCLA School of Medicine, Los Angeles, CA 90024. Checks should be made payable to: Regents of the University of California.
ADDENDUM More specific guidelines in infection control, the CDC pamphlet entitled Preventing the Transmission of Hepa-
Determination restorations
of demand for posterior resin
E. L. Davis, Ph.D.,* J. C. Laura,** R. B. Joynt, D.D.S.,*** and G. Wiebzkowski, Jr., D.D.S.**** State University
of New York at Buffalo, School of Dental Medicine, Buffalo, N.Y.
S
tudies indicate that 30% to 40% of adults are dissatisfied with their smiles, suggesting a significant potential for cosmetic dentistry.’ Although esthetics is assumed to be a major factor in the restoration of anterior teeth, this assumption cannot be made for posterior teeth. Research on dental esthetics has focused almost exclusively on anterior teeth.2s3In the absence of known studies concerning the,importance of the esthetics of posterior teeth, the current level of interest in posterior resin restorations is based on a perceived public demand for esthetics. Furthermore, no research has been done on patient awareness of, or interest in, composite as a posterior restorative material. Available posterior composites do not have the same degree of wear resistance as amalgam and are more technique-sensitive.‘-’ In addition, a recent study has Presented at the International Association for Dental Research, Chicago, Ill. Research supported in part by United States. Public Health Service grant No. DE07106. *Instructor, Departments of Operative Dentistry and Behavioral Sciences. **Dental student. ***Clinical Assistant Professor, Department of Operative Dentistry. ****Associate Professor and Chairman, Department of Operative Dentistry.
242
shown that posterior teeth restored with resin are no more resistant to fracture than those restored with ama.lgam.s At best, these materials represent a compromise in function for the sake of esthetics. Despite these major drawbacks, manufacturers’ sales promotions often claim that posterior resins are comparable or superior to traditional silver amalgam. This research determined the extent of public awareness regarding posterior resin restorations and the public’s interest in resin as a restorative material for posterior teeth. A secondary aim was to determine dentists’ attitudes toward resins for posterior tooth restorations and to compare their perceptions of these materials with those of sales representatives who market them.
METHODS Three populations of interest were included in the study: the general public, practicing general dentists, and dental sales representatives. All subjects were contacted by a dental student trained in survey techniques. The student followed the same general protocol for all three study groups: she identified herself and her affiliation, described the research briefly, and asked for the subject’s participation. Each of these groups will be described separately. FEBRUARY
1988
VOLUME
59
NUMBER
2
DEMAND FOR POSTERIOR RESIN RESTORATIONS
General public Subjects. Two-hundred adults were selected from the general public, chosen at The Greater Buffalo International Airport. Instrument. The survey instrument was a 34-item questionnaire consisting of two sections. Section A contained que:stions related to dentistry, including frequency of dental visits, source of dental information, and subjects’ awareness of and interest in posterior composite restorations. Section B asked for sociodemographic information, including age, sex, and education. All questions were interviewer-administered. Procedure. Each potential subject was approached in the airport by the interviewer. An interview format was chosen for this study, instead of a mail or telephone survey, to increase the response rate and to ensure that respondents understood the questions posed to them. The airport setting was used for sampling convenience. Economically, people in airports are not representative of the population as a whole; however, because they presumably have some quantity of disposable income, they may be more representative of potential consumers of composite lresin restorations than the population at large. Only rellidents of western New York were included, to ensure comparability among study groups. The interviewer conducted all interviews in terminals at which arrival:5 were expected because it was deemed likely that people at these terminals would be waiting for passengers to arrive instead of waiting to depart. Only persons who did not appear rushed or busy were approached, and an attempt was made to sample equitably from both sexes and all adult ages. The interviewer read each question to the subject, providing clarification of terminology when necessary. The entire interview took 3 to 4 minutes.
Dentists Subjects. Fifty full-time general-practice dentists were randomly selected from the Buffalo, N.Y. Metropolitan telephone book. Instrument. The survey instrument was a five-item questionnaire related to dentists’ use of posterior resin restorations, perceptions of patient demand for and sales representatives’ promotion of these materials, and perception of posterior resin durability. Procedure. The dentists were contacted by telephone, and the survey took approximately 2 to 3 minutes to complete.
Dental sales representatives Subjects. Six sales representatives servicing western New York for companies that manufacture posterior composite material were selected as subjects. This number constitutes the entire population of such representatives in western New York. Instrument. The survey instrument was a five-item THE JOURNAL OF PROSTHETIC DENTISTRY
Table I. Percent breakdown by age, sex, and education: General public survey results versus census data Survey resulta
1980 U.S. census data
18-65 Years
87
>65 Years*
13
83 17
Variabie
Age
Sext Men Women Education+
41 59
48 52
6 67 27
35 50 15
*The U.S. censuscategorizesthe population as “65 years and over” whereas the survey categorizedrespondentsas “over 65.” @emus data include all age groups; survey results limited to those aged 18 and over. #Census data include persons 25 years old and over; survey data include persons over age 25 years.
questionnaire related to perceived usage of posterior resin material by their dentist-clients, their promotion of posterior resin restorations, and their perceptions of the durability of posterior resin restorations. Procedure. All sales representatives were contacted by telephone, and the questionnaire took approximately 2 to 3 minutes to complete.
RESULTS General public survey Representativeness of sample. A total of 202 subjects, 83 men and 119 women, were interviewed. To determine the extent to which our sample was representative of residents of western New York, sample information on age, sex, and education was compared with data from the 1980 U.S. Census for Erie County (Table I). Age and sex distributions within the sample were similar to those in the census, with women slightly overrepresented. A significantly greater percentage of subjects in the sample achieved higher levels of education compared with the population as a whole as measured by the census. Thus, while age and sex ratios were representative of the population, people with 12 or more years of education were overrepresented and those with fewer than 12 years of education were underrepresented in the sample. General findings. A summary of general findings appears in Table II. Most respondents (89%) indicated that they visit the dentist at least once a year. More than half of the subjects (57%) were unaware that toothcolored materials could be used for posterior teeth. Among those who had heard of posterior resin restorations, the main source of this information was the dentist (59%). Of the total surveyed, 12% (n = 25) indicated that they have posterior resin restorations. Of these, only 20% had requested them. Only 17% of the total respon243
DAVIS
Table II. General findings, survey (N = 202)
ET AL
general public
Survey item 1. How often do you visit your dentist? At least twice a year Less than twice a year but at least once a year Less than once a year but at least once every two years Less than once every two years/only when you have a problem (such as a toothache) 2. Are you aware that tooth-colored (white) fillings can be used in back teeth? Yes No 3. (If yes to item 2) How did you learn of this? Dentist or dental pamphlet Friend or family member Media (tv, radio, magazine, or newspaper) At work Other Total* 4. Do you have any tooth-colored (white) fillings in your back teeth? YC?S No Don’t know 5. (If yes to item 4) Did you specifically request them or did your dentist just put them it? Requested them Dentist just put them in Total’
N
96
139 40
68.8 19.8
6
3.0
17
8.4
87 115
43.1 56.9
51 13 11
58.6 14.9 12.6
1 11 87
1.1 12.6 43.1
25 173 4
12.4 85.6 2.0
5 20 25
20.0 80.0 12.4
Swvev item 6. Would you want to replace your back fillings that are silver-colored with tooth-colored (white) fillings? Yes No Don’t know 7. If you needed a filling in a back tooth, would you request a tooth-colored (white) filling? Yes No 8. How important is it to you that your back teeth look nice, that is, that your fillings match your tooth color? Very important Somewhat important Not very important Not important at all 9. How satisfied are you with the way your back teeth look? Very satisfied Somewhat satisfied Neither satisfied nor dissatisfied Somewhat dissatisfied Very dissatisfied 10. Do you think that tooth-colored (white) fillings in your back teeth would: Last as long as silver fillings Not last as long as silver fillings Last longer than silver fillings Unsure/don’t know
N
%
35 162 5
17.3 80.2 2.5
100 102
49.5 50.5
62 103 33 4
30.7 51.0 16.3 2.0
65 86 21 25 5
32.2 42.6 10.4 12.4 2.5
50 24 14 114
24.8 11.9 6.9 56.4
*Percent for this category rcflccts percentageof total sample.
dents would be interested enough to have their current posterior restorations replaced with resin restorations. However, approximately 50% would request resin if a posterior restoration needed to be replaced. Most respondents (82%) considered .the esthetics of their posterior teeth to be somewhat or very important, and most (75%) were either somewhat or very satisfied with the current esthetics of their posterior teeth. More than half (56%) were unsure of how posterior resins compare with silver amalgam in terms of durability. Of those who ventured an opinion, 57% (n = 50) thought that resin would last as long as amalgam, 27% (n = 24) though that resin would not last as long, and 16% (n = 14) thought that it would last longer than amallx*. Sex di$eences. Significant sex differences are summarized in Table III. Women were more likely than men to have prior knowledge of posterior resin restorations (47% vs. 37%) (x2 = 1.50, p < .lO). Women were more 244
likely to report that they would request resin if they needed a posterior tooth restoration (x2 = 3.55, p < .lO) and that they would replace present posterior tooth restorations with resin (x2 = 12.23, p < ~301). There were also sex differences in the perceived importance of esthetics in posterior teeth and satisfaction with the present esthetics of their posterior teeth. Women were more likely than men to consider appearance to be either somewhat or very important ($ = 11.82, p < .OOl) and to be either somewhat or very dissatisfied with present esthetics (x” = 5.25, p < .lO). A significant sex difference was found in whether an opinion was held regarding durability of posterior resin restorations (x2 = 3.69, p < .lO). Although there was no sex difference in opinion regarding durability (any opinion vs. no opinion/unsure) among those with prior knowledge of posterior resin restorations, there was a significant sex difference in opinion among those with no previous knowledge of posterior resins (x2 = 4.00, FEBRUARY
1988
VOLUME
59
NUMBER
2
DEMAND
FOR F’OSTERIOR
RESIN
RESTORATIONS
Table III. Sex differences, general public survey (N = 202)’ ___Women
Men Survey
item
1. Are you aware that tooth-colored be used for back teeth? Yes
(white)
fillings
N
%
N
%
31 52
37.3 62.7
56 63
47.1 52.9
34 49
41.0 59.0
66 53
55.5 44.5
5 75
6.2 93.8
30 87
25.6 74.4
16 42 21 4
19.3 50.6 25.3 4.8
46
61 12 0
38.7 51.3 10.1 0.0
28 37 11 5 2
33.7 44.6 13.3 6.0 2.4
37 49 10 20 3
31.1 41.2 a.4 16.8 2.5
29 54
34.9 65.1
59 60
49.6 50.4
19 12
61.3 38.7
35 21
62.5 37.5
10 42
19.2 80.8
24 39
38.1 61.9
11 12 6
37.9 41.4 20.7
39 12 8
66.1 20.3 13.6
can
NO
2. If you needed a filling in a back tooth, would you request a tooth-colored (white) filling?t Yes No 3. Would you want to replace your back fillings that are silver-colored with tooth colored (white) fillings?+ Yes No 4. How important is it to you that your back teeth look nice, that is, that your fillings match your tooth color?* Very important Somewhat important Not very important Not important at all 5. How satisfied are you with the way your back teeth look?t Very satisfied Somewhat satisfied Neither satisfied nor dissatisfied Somewhat dissatisfied Very dissatisfied 6. Do you think that tooth-colored (white) fillings in your back teeth would last as long, not as long, longer than silver fillings (any opinion) versus unsure/don’t know (no opinion)?t Any opinion No opinion 7. Among those with prior knowledge of posterior resins: Do you think that tooth-colored (white) fillings in your back teeth would last as long, not as long, longer than silver 8.llings (any opinion) versus unsure/don’t know (no opinion)? Any opinion No opinion 8. Among those with no prior knowledge of posterior resinjl: Do you think that tooth-colored (white) fillings in your back teeth would last as long, not as long, longer than silver fillings (any opinion) versus unsureidon’t know (no opinion)?9 Any opinion No opinion 9. Among those with an opinion regarding posterior resin durability#: Do you think that tooth-colored (white) fillings in your back teeth would Last ilS long as silver fillings Not last as long as silver fillings Last longer than silver fillings *Percentage by sex. tChi square significant at p < .lO. $Chi square significant at p < 0.001. §N = 87 (31 men, 56 women). lp = 115 (52 men, 63 women). BChi square significant at p < 0.05. #Does not take into account prior knowledge; N = 88 (29 men, 59 women). THE JOURNAL
OF PR0STHEl-K
DENTISTRY
245
DAVIS
Table IV. General findings, dentist survey
Table V. General findings, sales representative survey (N = 6)
(N = 53) Survey item 1. Please estimate your posterior composite usage. Don’t use (5% 695-1096 1196-2596 26%-50% so% 2. Among those who use posterior resins: Why do you use them?* Esthetics Strengthens the tooth Patient demand/request For premolars only As a temporary restoration Other 3. Among those who do not use posterior resins, or who rarely use them?: Why don’t you use them?* Inferior materials Not enough information about them Harder to use than amalgam Postoperative sensitivity No ADA approval 4. What percentage of your patients request posterior resin restorations? 0% l%-5% 6%-10% 111-2596 26%-50% 5. Overall, do sales representatives promote the use of posterior resins? Yes No 6. If yes to item 5: Do sales representatives promote resins more than amalgam? Yes No 7. Functionally, do you think that current posterior composites are: Superior to amalgam Approximately the same as amalgam Inferior to amalgam Not sure
N
13 18 6 9 4 2
24 10 9 5 5 6
96
25.0 34.6 11.5 17.3 7.7 3.8
66.7 27.8 25.0 13.9 13.9 16.7
17 4
81.0 19.0
3 1 1
14.3 4.8 4.8
29 24
13.5 50.0 19.2 13.5 3.8
Mercury scare 3.
6.
54.7 45.3 *Multiple
7 20
25.9 74.1
1 7
1.9 13.2
35 10
66.0 18.9
p < .05). Women in this group were more likely than men to have some opinion regarding durability of posterior resins (38% of the women compared with 19% of the men). Among those with an opinion of posterior resin
N
1. What percentage of your dentist-clients use posterior composites? 10% 60% 7596-8046 8596-9046 Unsure/don’t know 2. If they use posterior resins, why do they?* Esthetics Strengthens the tooth
5.
*Multiple responses are possible. tFor this analysis, dentists who reported using the material less than 5% of the time were included; total n = 21.
246
Survey item
4.
7 26 10 7 2
ET AL
Other If they don’t use posterior resins, why don’t they?* New material; dentists are skeptical Harder to use than amalgam Inferior materials Other Overall, do you promote the use of posterior resins? Yes No Do you promote posterior resins more than amalgam? Yes Yes-company does not manufacture amalgam Yes, in selected areas (class I, conservative preparation) No Functionally, do you think that current posterior resins are: Superior to amalgam Approximately the same as amalgam Inferior to amalgam Better than amalgam in some respects, not better in others
1 1 1 1 2 5 3 2 7
4 2 2 6
6 0
1 1 1 3
1 2 1 2
responses are possible.
durability, regardless of prior knowledge, women were more likely than men to think that resin would last as long as amalgam (66% compared with 38%), whereas men were more apt than women to think that resin would not last as long (41% compared with 20%) (x2 = 6.49, fi < .05). Prior knowledge of posterior resins. Previous knowledge of posterior composites had no apparent effect on an individual’s willingness to replace present posterior restorations with resin restorations (17% of the sample, regardless of previous knowledge) or to request resin for posterior restorations that need replacement (52% of those with prior knowledge of posterior resin, 48% of those with no prior knowledge).
Dentist survey Fifty-three practicing general dentists from the western New York area comprised the dentist sample (Table IV). Twenty-five percent of the dentists surveyed FEBRUARY
1988
VOLUME
59
NUMBER
2
DEMAND
FOR F’OSTERIOR
RESIN
RBTORATIONS
(n = 13) indicated that they do not use posterior composites. Another 35% (n = 18) use the materials 5% of the time or less, and only two dentists reported using posterior resins more than 50% of the time. The major reason given for using posterior resins was esthetics (n = 24; 67%). Other reasons included a strengthening effect on tooth structure (28%) and patient demand or request (25%), The most common reason dentists do not use posterior resins is that they believe them to be inferior materials (n = 17; 81%). Other reasons given were that not enough is known about them (n = 4) and that they are harder to use (n = 3). Most dentists (83%) indicated that 10% or fewer of their patients request posterior resin restorations. Slightly more than half of the dentists surveyed (55%) reported that sales representatives promote the use of posterior resins, but only 26% of those responding (n = 7) thought that posterior resins were being promoted more than traditional amalgam materials. Most dentists (66%) thought that current posterior resins are inferior to amalgam, and only one believed that posterior resins are superior to amalgam.
Sales representative survey The population of all dental sales representatives in the western New York region whose companies market posterior composites was contacted for the study (n = 6). Sales representatives’ perceptions of posterior resin usage among dentists were varied (Table V). Two subjects did not know what percentage of their dentistclients use posterior resins. Of the four representatives who had an opinion, one thought that 10% use posterior resins, another thought that 60% use them, one indicated that 75% to 80% do, and one replied that 85% to 90% of his dentist-clients use posterior resins. The most frequently mentioned reason for their use was esthetics (n = S), followed by the strengthening effect on the tooth (n = 3). These results parallel the responses given by dentists. Two respondents believed that the “mercury scare” was also a factor in dentists’ decision to use resin. Sales representatives believe that the major reason dentists do not use posterior resins is that the materials are new and that dentists are skeptical (n = 4). Two representatives indicated that dentists do not use the materials because they are inferior or because they are harder to use. These results also match the findings of the dentist survey. All six representatives indicated that they promote the use of posterior resins. One respondent promotes resin. more than amalgam, one promotes it exclusively because his company does not manufacture amalgam, and one promotes resin more than amalgam only in the caseof conservative restorations. The remaining three sales representatives reported that they do not promote resin more than amalgam. When asked to compare the durability of amalgam and posterior resin, one thought that resin was superior THE JOURNAL
OF PROSTHETIC
DENTISTRY
to amalgam, one indicated that resin was inferior to amalgam, two thought they were approximately the same, and two representatives replied that amalgam is superior in some respects and resin is superior in other respects.
DISCUSSION Several conclusions can be drawn on the basis of these results. First, dentists are far more discerning and conservative regarding posterior resins than was previously thought. One reason for this overestimate of posterior resin usage among dentists may be found in the surveys we conducted. Dentists and sales representatives were asked to estimate the percentage of posterior resin usage in dental offices. Although the dentists reported relatively little usage of the material, sales representatives estimated a much higher percentage. It may be conjectured that sales representatives’ basis for comparison is sales of the material instead of actual usage. Thus, although most dentists may have experimented with posterior resins to form an opinion of them, few use the materials on a regular basis. A second conclusion can be made thaf sales representatives are optimistic about posterior resins. Dentist comments tended to emphasize shortcomings of present resin materials, whereas sales representatives emphasized future improvements and increased usage. Only one of the six sales representatives indicated, unconditionally, that present posterior resins are functionally inferior to amalgam. A major argument for posterior resin restorations within the industry has been that there is a patient demand that must be met. We did not find a great demand for posterior resin restorations among the general public. More than half of the individuals surveyed (57%) were not even aware that tooth-colored materials could be used for posterior restorations. Although the appearance of posterior teeth was judged to be either somewhat (5 1%) or very important (31%), only a small percentage of the sample indicated that they would replace present posterior restorations with resin (17%). It appears that esthetics is not the primary factor in determining whether one is willing to replace posterior restorations. Nevertheless, the public seems willing to accept posterior resins as a viable alternative to amalgam with little or no knowledge about them. Nearly half of those with no prior knowledge of posterior resins stated that they would request resin for back teeth that needed restorations. In addition, nearly 25% of the people surveyed believed that posterior resin restorations would last as long as amalgam restorations. There appears to be a common belief among the general public that if a material is on the market, it must be good. It should be noted that subjects were asked unconditional questions regarding posterior resins. That is, they were asked if they would request or replace posterior restorations regardless of other factors such as cost or 247
DAVIS
durability. The determination of additional factors influencing the decision to request posterior resin, and their importance relative to esthetic considerations, is necessary before a true estimate of patient demand can be made. It should also be noted that these subjects were not truly representative of the population from which they were drawn. Their educational attainment was significantly higher, and a much higher percentage reported visiting a dentist at least once a year (89% compared with the Public Health Service estimate of 41%).9 These discrepancies suggest a profile of individuals who are more likely than the general population to become aware of, and to pursue information on, posterior composites. Because they are representative of individuals who visit the dentist on a regular basis, dentists should be aware of the potential interest in these materials and be prepared to discuss advantages and disadvantages with their patients. Finally, several dentists (n = 10) and half of the sales representatives (n = 3) indicated a strengthening effect on tooth structure as one reason for using posterior resins. Recent research shows that, in structurally weakened teeth, resistance to fracture is no greater among teeth restored with posterior resin than among those restored with amalgam.* Unless one is preparing a very conservative cavity preparation, a strengthening effect of resin on tooth structure should not be anticipated.
ET AL
current esthetic procedures. J PROSTHET DENT 1984;52:775-
80. 2. Tjan AHL, Miller 3. 4.
5. 6. 7.
8. 9.
GD, The JGP. Some esthetic factors in a smile. J PROSTHETDENT 1984;51:24-8. B&man AS, Hirsch SM. A concept of esthetics. NY State Dent J 1985;51:462-5. Leinfelder KF, Sluder TB, Sockwell CL, Strickland WD, Wall JT. Clinical evaluation of composite resins as anterior and posterior restorative materials. J F’ROSTHETDENT 1975;33:40716. Leinfelder KF. Composite resins-symposium on restorative dentistry. Dent Clin North Am 1985;29:359-71. Wilder AD Jr, May KN Jr, Leinfelder KF. Three-year clinical study of UV-cured composite resins in posterior teeth. J PROSTHET DENT 1983;50:26-30. Eick JD, Welch FH. Polymerization shrinkage of posterior composite resins and its possible influence on postoperative sensitivity. Quintessence Int 1986;17:103-11. Joynt RB, Wienkowski G Jr, Klockowski R, Davis EL. Effects of composite restorations on resistance to cuspal fracture in posterior teeth. J F%XTHET DENT 1987;57:431-5. Dental services: use, expenditures, and sources of payment. DHHS Publication No. (PHS) 82-3319. Hyattsville, Md: U.S. Department of Health and Human Services National Center for Health Services Research, October 1982.
Reprint requeststo: DR. ELAINE L. D.WIS STATE UNIVERSITYOF NEW YORK AT BUFFAM SCHOOLOF DENTAL MEDICINE BUFFAM. NY 14214
REFERENCES 1.
Goldstein RE, Lancaster JS. Survey of patient attitudes toward
Bound volumes available to subscribers Bound volumes of the JOURNALOFPROSTHETIC DENTISTRY are available to subscribers (only) for the 1966 issues from the publisher at a cost of $44.00 ($56.90 international) for Vol. 59 (January-June) and VoL 60 (July-December). Shipping charges are included. Each bound volume contains a subject and author index, and all advertising is removed. Copies are shipped within 30 days after publication of the last issue in the volume. The binding is durable buckram with the journal name, volume number, and year stamped in gold on the spine. Payment must accompany all orders. Contact The C. V. Mosby Co., Circulation Department, 11830 We&me Industrial Drive, St. Louis, MO 63146, USA; phone (800) 325-4177, ext. 351. Subscriptions must JOUENAL subscription.
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be in force
to qualiiy.
Bound
volumes
are
not available
FEBRUARY
in place
1988
of a regular
VOLUME
59
NUMBER
2
29.
Penny R. Aids to the laboratory diagnosis of AIDS. Pathology 1984;16:375. Centers for Interdisciplinary Research in Immunology and Diseases at UCLA. AIDS: reference guide for medical professionals. Los Angeles, Calif: UCLA School of Medicine, 1984. Wilkins EGL, et al. Difficulties in the diagnosis of acquired immune deficiency syndrome. Am J Clin Path01 1984;37:1316.
Reprint requests to: DR. FREDRIC A. MOORE 10~~ MEDICAL DETACHMENT (DS) CAMP CASEY,KOREA APO SAN FRANCI~~, CA 96224
titis B, AIDS, and Herpes in Dent&y can be obtained free of charge by writing to Centers for Disease Control, Center for Preventive Services, Dental Disease Prevention Activity, Atlanta, GA 30333. A beneficial guide that outlines many of the basics of AIDS is entitled AIDS: Reference Guide for Medical Professionals, and can be obtained by sending $3.50 to CIRID/Outreach and Education, c/o Dept. of Microbiology and Immunology, UCLA School of Medicine, Los Angeles, CA 90024. Checks should be made payable to: Regents of the University of California.
ADDENDUM More specific guidelines in infection control, the CDC pamphlet entitled Preventing the Transmission of Hepa-
Determination restorations
of demand for posterior resin
E. L. Davis, Ph.D.,* J. C. Laura,** R. B. Joynt, D.D.S.,*** and G. Wiebzkowski, Jr., D.D.S.**** State University
of New York at Buffalo, School of Dental Medicine, Buffalo, N.Y.
S
tudies indicate that 30% to 40% of adults are dissatisfied with their smiles, suggesting a significant potential for cosmetic dentistry.’ Although esthetics is assumed to be a major factor in the restoration of anterior teeth, this assumption cannot be made for posterior teeth. Research on dental esthetics has focused almost exclusively on anterior teeth.2s3In the absence of known studies concerning the,importance of the esthetics of posterior teeth, the current level of interest in posterior resin restorations is based on a perceived public demand for esthetics. Furthermore, no research has been done on patient awareness of, or interest in, composite as a posterior restorative material. Available posterior composites do not have the same degree of wear resistance as amalgam and are more technique-sensitive.‘-’ In addition, a recent study has Presented at the International Association for Dental Research, Chicago, Ill. Research supported in part by United States. Public Health Service grant No. DE07106. *Instructor, Departments of Operative Dentistry and Behavioral Sciences. **Dental student. ***Clinical Assistant Professor, Department of Operative Dentistry. ****Associate Professor and Chairman, Department of Operative Dentistry.
242
shown that posterior teeth restored with resin are no more resistant to fracture than those restored with ama.lgam.s At best, these materials represent a compromise in function for the sake of esthetics. Despite these major drawbacks, manufacturers’ sales promotions often claim that posterior resins are comparable or superior to traditional silver amalgam. This research determined the extent of public awareness regarding posterior resin restorations and the public’s interest in resin as a restorative material for posterior teeth. A secondary aim was to determine dentists’ attitudes toward resins for posterior tooth restorations and to compare their perceptions of these materials with those of sales representatives who market them.
METHODS Three populations of interest were included in the study: the general public, practicing general dentists, and dental sales representatives. All subjects were contacted by a dental student trained in survey techniques. The student followed the same general protocol for all three study groups: she identified herself and her affiliation, described the research briefly, and asked for the subject’s participation. Each of these groups will be described separately. FEBRUARY
1988
VOLUME
59
NUMBER
2
DEMAND FOR POSTERIOR RESIN RESTORATIONS
General public Subjects. Two-hundred adults were selected from the general public, chosen at The Greater Buffalo International Airport. Instrument. The survey instrument was a 34-item questionnaire consisting of two sections. Section A contained que:stions related to dentistry, including frequency of dental visits, source of dental information, and subjects’ awareness of and interest in posterior composite restorations. Section B asked for sociodemographic information, including age, sex, and education. All questions were interviewer-administered. Procedure. Each potential subject was approached in the airport by the interviewer. An interview format was chosen for this study, instead of a mail or telephone survey, to increase the response rate and to ensure that respondents understood the questions posed to them. The airport setting was used for sampling convenience. Economically, people in airports are not representative of the population as a whole; however, because they presumably have some quantity of disposable income, they may be more representative of potential consumers of composite lresin restorations than the population at large. Only rellidents of western New York were included, to ensure comparability among study groups. The interviewer conducted all interviews in terminals at which arrival:5 were expected because it was deemed likely that people at these terminals would be waiting for passengers to arrive instead of waiting to depart. Only persons who did not appear rushed or busy were approached, and an attempt was made to sample equitably from both sexes and all adult ages. The interviewer read each question to the subject, providing clarification of terminology when necessary. The entire interview took 3 to 4 minutes.
Dentists Subjects. Fifty full-time general-practice dentists were randomly selected from the Buffalo, N.Y. Metropolitan telephone book. Instrument. The survey instrument was a five-item questionnaire related to dentists’ use of posterior resin restorations, perceptions of patient demand for and sales representatives’ promotion of these materials, and perception of posterior resin durability. Procedure. The dentists were contacted by telephone, and the survey took approximately 2 to 3 minutes to complete.
Dental sales representatives Subjects. Six sales representatives servicing western New York for companies that manufacture posterior composite material were selected as subjects. This number constitutes the entire population of such representatives in western New York. Instrument. The survey instrument was a five-item THE JOURNAL OF PROSTHETIC DENTISTRY
Table I. Percent breakdown by age, sex, and education: General public survey results versus census data Survey resulta
1980 U.S. census data
18-65 Years
87
>65 Years*
13
83 17
Variabie
Age
Sext Men Women Education+
41 59
48 52
6 67 27
35 50 15
*The U.S. censuscategorizesthe population as “65 years and over” whereas the survey categorizedrespondentsas “over 65.” @emus data include all age groups; survey results limited to those aged 18 and over. #Census data include persons 25 years old and over; survey data include persons over age 25 years.
questionnaire related to perceived usage of posterior resin material by their dentist-clients, their promotion of posterior resin restorations, and their perceptions of the durability of posterior resin restorations. Procedure. All sales representatives were contacted by telephone, and the questionnaire took approximately 2 to 3 minutes to complete.
RESULTS General public survey Representativeness of sample. A total of 202 subjects, 83 men and 119 women, were interviewed. To determine the extent to which our sample was representative of residents of western New York, sample information on age, sex, and education was compared with data from the 1980 U.S. Census for Erie County (Table I). Age and sex distributions within the sample were similar to those in the census, with women slightly overrepresented. A significantly greater percentage of subjects in the sample achieved higher levels of education compared with the population as a whole as measured by the census. Thus, while age and sex ratios were representative of the population, people with 12 or more years of education were overrepresented and those with fewer than 12 years of education were underrepresented in the sample. General findings. A summary of general findings appears in Table II. Most respondents (89%) indicated that they visit the dentist at least once a year. More than half of the subjects (57%) were unaware that toothcolored materials could be used for posterior teeth. Among those who had heard of posterior resin restorations, the main source of this information was the dentist (59%). Of the total surveyed, 12% (n = 25) indicated that they have posterior resin restorations. Of these, only 20% had requested them. Only 17% of the total respon243
DAVIS
Table II. General findings, survey (N = 202)
ET AL
general public
Survey item 1. How often do you visit your dentist? At least twice a year Less than twice a year but at least once a year Less than once a year but at least once every two years Less than once every two years/only when you have a problem (such as a toothache) 2. Are you aware that tooth-colored (white) fillings can be used in back teeth? Yes No 3. (If yes to item 2) How did you learn of this? Dentist or dental pamphlet Friend or family member Media (tv, radio, magazine, or newspaper) At work Other Total* 4. Do you have any tooth-colored (white) fillings in your back teeth? YC?S No Don’t know 5. (If yes to item 4) Did you specifically request them or did your dentist just put them it? Requested them Dentist just put them in Total’
N
96
139 40
68.8 19.8
6
3.0
17
8.4
87 115
43.1 56.9
51 13 11
58.6 14.9 12.6
1 11 87
1.1 12.6 43.1
25 173 4
12.4 85.6 2.0
5 20 25
20.0 80.0 12.4
Swvev item 6. Would you want to replace your back fillings that are silver-colored with tooth-colored (white) fillings? Yes No Don’t know 7. If you needed a filling in a back tooth, would you request a tooth-colored (white) filling? Yes No 8. How important is it to you that your back teeth look nice, that is, that your fillings match your tooth color? Very important Somewhat important Not very important Not important at all 9. How satisfied are you with the way your back teeth look? Very satisfied Somewhat satisfied Neither satisfied nor dissatisfied Somewhat dissatisfied Very dissatisfied 10. Do you think that tooth-colored (white) fillings in your back teeth would: Last as long as silver fillings Not last as long as silver fillings Last longer than silver fillings Unsure/don’t know
N
%
35 162 5
17.3 80.2 2.5
100 102
49.5 50.5
62 103 33 4
30.7 51.0 16.3 2.0
65 86 21 25 5
32.2 42.6 10.4 12.4 2.5
50 24 14 114
24.8 11.9 6.9 56.4
*Percent for this category rcflccts percentageof total sample.
dents would be interested enough to have their current posterior restorations replaced with resin restorations. However, approximately 50% would request resin if a posterior restoration needed to be replaced. Most respondents (82%) considered .the esthetics of their posterior teeth to be somewhat or very important, and most (75%) were either somewhat or very satisfied with the current esthetics of their posterior teeth. More than half (56%) were unsure of how posterior resins compare with silver amalgam in terms of durability. Of those who ventured an opinion, 57% (n = 50) thought that resin would last as long as amalgam, 27% (n = 24) though that resin would not last as long, and 16% (n = 14) thought that it would last longer than amallx*. Sex di$eences. Significant sex differences are summarized in Table III. Women were more likely than men to have prior knowledge of posterior resin restorations (47% vs. 37%) (x2 = 1.50, p < .lO). Women were more 244
likely to report that they would request resin if they needed a posterior tooth restoration (x2 = 3.55, p < .lO) and that they would replace present posterior tooth restorations with resin (x2 = 12.23, p < ~301). There were also sex differences in the perceived importance of esthetics in posterior teeth and satisfaction with the present esthetics of their posterior teeth. Women were more likely than men to consider appearance to be either somewhat or very important ($ = 11.82, p < .OOl) and to be either somewhat or very dissatisfied with present esthetics (x” = 5.25, p < .lO). A significant sex difference was found in whether an opinion was held regarding durability of posterior resin restorations (x2 = 3.69, p < .lO). Although there was no sex difference in opinion regarding durability (any opinion vs. no opinion/unsure) among those with prior knowledge of posterior resin restorations, there was a significant sex difference in opinion among those with no previous knowledge of posterior resins (x2 = 4.00, FEBRUARY
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Table III. Sex differences, general public survey (N = 202)’ ___Women
Men Survey
item
1. Are you aware that tooth-colored be used for back teeth? Yes
(white)
fillings
N
%
N
%
31 52
37.3 62.7
56 63
47.1 52.9
34 49
41.0 59.0
66 53
55.5 44.5
5 75
6.2 93.8
30 87
25.6 74.4
16 42 21 4
19.3 50.6 25.3 4.8
46
61 12 0
38.7 51.3 10.1 0.0
28 37 11 5 2
33.7 44.6 13.3 6.0 2.4
37 49 10 20 3
31.1 41.2 a.4 16.8 2.5
29 54
34.9 65.1
59 60
49.6 50.4
19 12
61.3 38.7
35 21
62.5 37.5
10 42
19.2 80.8
24 39
38.1 61.9
11 12 6
37.9 41.4 20.7
39 12 8
66.1 20.3 13.6
can
NO
2. If you needed a filling in a back tooth, would you request a tooth-colored (white) filling?t Yes No 3. Would you want to replace your back fillings that are silver-colored with tooth colored (white) fillings?+ Yes No 4. How important is it to you that your back teeth look nice, that is, that your fillings match your tooth color?* Very important Somewhat important Not very important Not important at all 5. How satisfied are you with the way your back teeth look?t Very satisfied Somewhat satisfied Neither satisfied nor dissatisfied Somewhat dissatisfied Very dissatisfied 6. Do you think that tooth-colored (white) fillings in your back teeth would last as long, not as long, longer than silver fillings (any opinion) versus unsure/don’t know (no opinion)?t Any opinion No opinion 7. Among those with prior knowledge of posterior resins: Do you think that tooth-colored (white) fillings in your back teeth would last as long, not as long, longer than silver 8.llings (any opinion) versus unsure/don’t know (no opinion)? Any opinion No opinion 8. Among those with no prior knowledge of posterior resinjl: Do you think that tooth-colored (white) fillings in your back teeth would last as long, not as long, longer than silver fillings (any opinion) versus unsureidon’t know (no opinion)?9 Any opinion No opinion 9. Among those with an opinion regarding posterior resin durability#: Do you think that tooth-colored (white) fillings in your back teeth would Last ilS long as silver fillings Not last as long as silver fillings Last longer than silver fillings *Percentage by sex. tChi square significant at p < .lO. $Chi square significant at p < 0.001. §N = 87 (31 men, 56 women). lp = 115 (52 men, 63 women). BChi square significant at p < 0.05. #Does not take into account prior knowledge; N = 88 (29 men, 59 women). THE JOURNAL
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245
DAVIS
Table IV. General findings, dentist survey
Table V. General findings, sales representative survey (N = 6)
(N = 53) Survey item 1. Please estimate your posterior composite usage. Don’t use (5% 695-1096 1196-2596 26%-50% so% 2. Among those who use posterior resins: Why do you use them?* Esthetics Strengthens the tooth Patient demand/request For premolars only As a temporary restoration Other 3. Among those who do not use posterior resins, or who rarely use them?: Why don’t you use them?* Inferior materials Not enough information about them Harder to use than amalgam Postoperative sensitivity No ADA approval 4. What percentage of your patients request posterior resin restorations? 0% l%-5% 6%-10% 111-2596 26%-50% 5. Overall, do sales representatives promote the use of posterior resins? Yes No 6. If yes to item 5: Do sales representatives promote resins more than amalgam? Yes No 7. Functionally, do you think that current posterior composites are: Superior to amalgam Approximately the same as amalgam Inferior to amalgam Not sure
N
13 18 6 9 4 2
24 10 9 5 5 6
96
25.0 34.6 11.5 17.3 7.7 3.8
66.7 27.8 25.0 13.9 13.9 16.7
17 4
81.0 19.0
3 1 1
14.3 4.8 4.8
29 24
13.5 50.0 19.2 13.5 3.8
Mercury scare 3.
6.
54.7 45.3 *Multiple
7 20
25.9 74.1
1 7
1.9 13.2
35 10
66.0 18.9
p < .05). Women in this group were more likely than men to have some opinion regarding durability of posterior resins (38% of the women compared with 19% of the men). Among those with an opinion of posterior resin
N
1. What percentage of your dentist-clients use posterior composites? 10% 60% 7596-8046 8596-9046 Unsure/don’t know 2. If they use posterior resins, why do they?* Esthetics Strengthens the tooth
5.
*Multiple responses are possible. tFor this analysis, dentists who reported using the material less than 5% of the time were included; total n = 21.
246
Survey item
4.
7 26 10 7 2
ET AL
Other If they don’t use posterior resins, why don’t they?* New material; dentists are skeptical Harder to use than amalgam Inferior materials Other Overall, do you promote the use of posterior resins? Yes No Do you promote posterior resins more than amalgam? Yes Yes-company does not manufacture amalgam Yes, in selected areas (class I, conservative preparation) No Functionally, do you think that current posterior resins are: Superior to amalgam Approximately the same as amalgam Inferior to amalgam Better than amalgam in some respects, not better in others
1 1 1 1 2 5 3 2 7
4 2 2 6
6 0
1 1 1 3
1 2 1 2
responses are possible.
durability, regardless of prior knowledge, women were more likely than men to think that resin would last as long as amalgam (66% compared with 38%), whereas men were more apt than women to think that resin would not last as long (41% compared with 20%) (x2 = 6.49, fi < .05). Prior knowledge of posterior resins. Previous knowledge of posterior composites had no apparent effect on an individual’s willingness to replace present posterior restorations with resin restorations (17% of the sample, regardless of previous knowledge) or to request resin for posterior restorations that need replacement (52% of those with prior knowledge of posterior resin, 48% of those with no prior knowledge).
Dentist survey Fifty-three practicing general dentists from the western New York area comprised the dentist sample (Table IV). Twenty-five percent of the dentists surveyed FEBRUARY
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(n = 13) indicated that they do not use posterior composites. Another 35% (n = 18) use the materials 5% of the time or less, and only two dentists reported using posterior resins more than 50% of the time. The major reason given for using posterior resins was esthetics (n = 24; 67%). Other reasons included a strengthening effect on tooth structure (28%) and patient demand or request (25%), The most common reason dentists do not use posterior resins is that they believe them to be inferior materials (n = 17; 81%). Other reasons given were that not enough is known about them (n = 4) and that they are harder to use (n = 3). Most dentists (83%) indicated that 10% or fewer of their patients request posterior resin restorations. Slightly more than half of the dentists surveyed (55%) reported that sales representatives promote the use of posterior resins, but only 26% of those responding (n = 7) thought that posterior resins were being promoted more than traditional amalgam materials. Most dentists (66%) thought that current posterior resins are inferior to amalgam, and only one believed that posterior resins are superior to amalgam.
Sales representative survey The population of all dental sales representatives in the western New York region whose companies market posterior composites was contacted for the study (n = 6). Sales representatives’ perceptions of posterior resin usage among dentists were varied (Table V). Two subjects did not know what percentage of their dentistclients use posterior resins. Of the four representatives who had an opinion, one thought that 10% use posterior resins, another thought that 60% use them, one indicated that 75% to 80% do, and one replied that 85% to 90% of his dentist-clients use posterior resins. The most frequently mentioned reason for their use was esthetics (n = S), followed by the strengthening effect on the tooth (n = 3). These results parallel the responses given by dentists. Two respondents believed that the “mercury scare” was also a factor in dentists’ decision to use resin. Sales representatives believe that the major reason dentists do not use posterior resins is that the materials are new and that dentists are skeptical (n = 4). Two representatives indicated that dentists do not use the materials because they are inferior or because they are harder to use. These results also match the findings of the dentist survey. All six representatives indicated that they promote the use of posterior resins. One respondent promotes resin. more than amalgam, one promotes it exclusively because his company does not manufacture amalgam, and one promotes resin more than amalgam only in the caseof conservative restorations. The remaining three sales representatives reported that they do not promote resin more than amalgam. When asked to compare the durability of amalgam and posterior resin, one thought that resin was superior THE JOURNAL
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to amalgam, one indicated that resin was inferior to amalgam, two thought they were approximately the same, and two representatives replied that amalgam is superior in some respects and resin is superior in other respects.
DISCUSSION Several conclusions can be drawn on the basis of these results. First, dentists are far more discerning and conservative regarding posterior resins than was previously thought. One reason for this overestimate of posterior resin usage among dentists may be found in the surveys we conducted. Dentists and sales representatives were asked to estimate the percentage of posterior resin usage in dental offices. Although the dentists reported relatively little usage of the material, sales representatives estimated a much higher percentage. It may be conjectured that sales representatives’ basis for comparison is sales of the material instead of actual usage. Thus, although most dentists may have experimented with posterior resins to form an opinion of them, few use the materials on a regular basis. A second conclusion can be made thaf sales representatives are optimistic about posterior resins. Dentist comments tended to emphasize shortcomings of present resin materials, whereas sales representatives emphasized future improvements and increased usage. Only one of the six sales representatives indicated, unconditionally, that present posterior resins are functionally inferior to amalgam. A major argument for posterior resin restorations within the industry has been that there is a patient demand that must be met. We did not find a great demand for posterior resin restorations among the general public. More than half of the individuals surveyed (57%) were not even aware that tooth-colored materials could be used for posterior restorations. Although the appearance of posterior teeth was judged to be either somewhat (5 1%) or very important (31%), only a small percentage of the sample indicated that they would replace present posterior restorations with resin (17%). It appears that esthetics is not the primary factor in determining whether one is willing to replace posterior restorations. Nevertheless, the public seems willing to accept posterior resins as a viable alternative to amalgam with little or no knowledge about them. Nearly half of those with no prior knowledge of posterior resins stated that they would request resin for back teeth that needed restorations. In addition, nearly 25% of the people surveyed believed that posterior resin restorations would last as long as amalgam restorations. There appears to be a common belief among the general public that if a material is on the market, it must be good. It should be noted that subjects were asked unconditional questions regarding posterior resins. That is, they were asked if they would request or replace posterior restorations regardless of other factors such as cost or 247
DAVIS
durability. The determination of additional factors influencing the decision to request posterior resin, and their importance relative to esthetic considerations, is necessary before a true estimate of patient demand can be made. It should also be noted that these subjects were not truly representative of the population from which they were drawn. Their educational attainment was significantly higher, and a much higher percentage reported visiting a dentist at least once a year (89% compared with the Public Health Service estimate of 41%).9 These discrepancies suggest a profile of individuals who are more likely than the general population to become aware of, and to pursue information on, posterior composites. Because they are representative of individuals who visit the dentist on a regular basis, dentists should be aware of the potential interest in these materials and be prepared to discuss advantages and disadvantages with their patients. Finally, several dentists (n = 10) and half of the sales representatives (n = 3) indicated a strengthening effect on tooth structure as one reason for using posterior resins. Recent research shows that, in structurally weakened teeth, resistance to fracture is no greater among teeth restored with posterior resin than among those restored with amalgam.* Unless one is preparing a very conservative cavity preparation, a strengthening effect of resin on tooth structure should not be anticipated.
ET AL
current esthetic procedures. J PROSTHET DENT 1984;52:775-
80. 2. Tjan AHL, Miller 3. 4.
5. 6. 7.
8. 9.
GD, The JGP. Some esthetic factors in a smile. J PROSTHETDENT 1984;51:24-8. B&man AS, Hirsch SM. A concept of esthetics. NY State Dent J 1985;51:462-5. Leinfelder KF, Sluder TB, Sockwell CL, Strickland WD, Wall JT. Clinical evaluation of composite resins as anterior and posterior restorative materials. J F’ROSTHETDENT 1975;33:40716. Leinfelder KF. Composite resins-symposium on restorative dentistry. Dent Clin North Am 1985;29:359-71. Wilder AD Jr, May KN Jr, Leinfelder KF. Three-year clinical study of UV-cured composite resins in posterior teeth. J PROSTHET DENT 1983;50:26-30. Eick JD, Welch FH. Polymerization shrinkage of posterior composite resins and its possible influence on postoperative sensitivity. Quintessence Int 1986;17:103-11. Joynt RB, Wienkowski G Jr, Klockowski R, Davis EL. Effects of composite restorations on resistance to cuspal fracture in posterior teeth. J F%XTHET DENT 1987;57:431-5. Dental services: use, expenditures, and sources of payment. DHHS Publication No. (PHS) 82-3319. Hyattsville, Md: U.S. Department of Health and Human Services National Center for Health Services Research, October 1982.
Reprint requeststo: DR. ELAINE L. D.WIS STATE UNIVERSITYOF NEW YORK AT BUFFAM SCHOOLOF DENTAL MEDICINE BUFFAM. NY 14214
REFERENCES 1.
Goldstein RE, Lancaster JS. Survey of patient attitudes toward
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