The quality of restorative dental care Joseph E. Grasso, D.D.S., M.S.,* John Nalbandian, Howard Bailit, D. M. D., Ph.D. * * * * University

of Connecticut,

School of Dental Medicine, Farmington,

Q

uality assurance monitoring is becoming a routine part of publicly financed and “thirdparty-administered” dental programs. The basic assumptions underlying these review systems are that the quality of dental care can be substantially improved and that improvement will lead to better oral health. A further assumption is that quality review systems are more cost-effective than other methods of improving oral health. Despite all the resources presently being allocated to monitoring dental care, relatively little research has been published on this topic. The few population surveys of the quality of dental care are limited because of sampling biases, use of implicit rather than explicit quality criteria, lack of specificity on the types of quality inadequacies found, and varying units of analysis (e.g., people, teeth or tooth surfaces). With these differences in study methodology, it is not surprising that estimates of inadequate dental care vary greatly.‘.’ Assuming that the quality of dental care can be improved, the critical and unanswered question is what will be accomplished by such an improvement. An important first step in answering this question and developing effective social policies on quality assurance is to define the amount of quality improvement possible in each major dental treatment area. With this basic issue in mind, this study reports on an investigation of the technical quality of restorative dental care in a population of employees at the University of Connecticut Health Center. Subsequent articles in this series will address the other important issues of the relationship between quality This project was supported in part by Grant No. 336-75 from the University of Connecticut Research Foundation. *Associate Professor, Department of Restorative Dentistry. **Professor, Department of Periodontics. ***Assistant Professor, Division of Family Dentistry. ****Professor, Department of Behavioral Science and Community Health.

0022-3913/79/

110571

+ 08$00.80/O

D.M.D.,**

0 1979 The

C. V. Mosby

Co.

Collin

Sanford, D.M.D.,“**

and

Conn.

Table I. Agreement quality

among

examiners

on

indices

Amalgams Crowns

variation and oral health and the cost-effectiveness of quality assurance systems.

METHOD Notices were sent to all University of Connecticut Health Center employees (excluding students) requesting their participation in the study. As a result of three mailings, 291 people were examined, a response rate of about 13%. For each subject, an assessment was made of the technical quality of restorations, crowns, and fixed partial dentures. Clinical examinations were performed with mirror and explorer. Radiographs were not used. The technical quality of restorative and prosthetic services3 was assessed using explicit criteria developed and tested by Bailit and associates.” The criteria are relevant to the following services: amalgams, inlays, composites, single crowns, fixed partial denture abutments, and pontics. In this assessment system, each restoration is rated for several quality categories, such as occlusion? contour, and gingivocavo surface margins. Each category has one or more explicit criteria which define the content of adequate care. A given quality category is scored adequate if all criteria in the category are met. An inadequate score is assigned when one or more of the criteria are not met. The percentage of adequate scores can then be averaged per criterion and per quality category or per tooth surface, per restoration, or per mouth. The examinations were performed by three University of Connecticut School of Dental Medicine faculty

THE JOURNAL OF PROSTHETIC DENTISTRY

571

GRASS0

Table II. Rating of occlusion

(percentages)

Amalgams (n = 2,448)

Inlays (n = 107)

Single crowns (n = 108)

Fixed partial denture abutments (n = 85)

99.3

96.4

97.2

97.6

1.8 0.9

2.4

3.6

Adequate Inadequate

Occlusal anatomy does not follow contour of tooth Occlusal prematurities present Tooth in infraocclusion

0.1

0.3 0.2

Table III. Rating of occlusal cavosurface

margins

and proximal (percentages)

Amalgams (n = 2,470)

Inlays (n = 107)

Composites (n = 252)

Adequate Inadequate Fractured or pitted margins

80.9

94.4

90.9

14.7

5.6

6.4

Margins do not fol-

4.4

2.8

low contour of tooth

members who were trained for 12 hours in the use of the quality measures. During this time, 25 patients were each examined independently by pairs of examiners to determine interrater reliability.

RESULTS The average age of the study subjects was 32.3 years with a range from 18 to 69 years. Most subjects were women (60.3%). The majority of subjects (76.5%) had at least some college education, and many (37.4%) had postbaccalaureate education. The annual family incomes of subjects showed a broad distribution, with 25% under $10,000 and 18% above $20,000. The subjects were not representative of the general population; they were characteristic of the well-educated but modestly paid personnel found in an academic setting. The interrater reliability scores for all quality indices for amalgams and crowns are given in Table I. These scores are within the range reported by other investigators and suggest that reasonable interrater reliability was achieved.“-‘? The data on the quality of restorations are presented for each quality category for the different types of restorations by tooth surface. The reasons for inadequate scores are noted. Results for occlusion are

572

ET AL

shown in Table II, and it is apparent that almost all restorations met the occlusal criteria. Table III presents data on occlusal and proximal cavosurface margins. Amalgams were the only restoration with a significant problem: 14.7% of the amalgam restorations had margins that were either fractured or pitted. Table IV considers gingivocavo surface margins, and as expected, with the exceptions of inlays and composites, the percentage of restorations meeting all criteria was substantially lower. Surfaces were rated as inadequate in 20% to 25% of amalgams. The major reason for an inadequate score was gingivocavo surface margins that were poorly adapted to the tooth. Single gold crowns and fixed partial denture abutments had the lowest scores, with 30% to 40% rated as inadequate. The main reason for the inadequacies was lack of marginal integrity. Table V gives the results for embrasures and contour. Amalgams, inlays, and composites were generally rated high, with less than 15% assessed as inadequate. In contrast, single crowns and fixed partial denture abutments were rated much lower, with 25% to 30% scored as inadequate. Table VI shows the data for marginal ridges. For all types of restorations most criteria were considered adequate by the assessors. Where a problem existed, it was generally related to the marginal ridge not being the same height as the adjacent marginal ridge. Table VII indicates that for the relatively few pontics that were assessed, a large percentage (40% to 50%) were inadequate mainly because of general overcontouring which resulted in poor access for cleaning. Pontic occlusion was not a problem.

DISCUSSION Attempts to estimate the quality of dental treatment in a community must consider two basic problems: (1) selecting a representative sample and

NOVEMBER

1979

VOLUME

42

NUMBER

5

RESTORATIVE

DENTAL

CARE

Table IV. Rating of gingivocavo

surface

margins

(percentages)

Amalgams Mesial (n = 995) Adequate Inadequate Fractured or pitted Margins do not follow contour of tooth Gingivai overhang

Buccal

Lingual

Mesial

Distal

Buccal

Lingual

(?I = 416)

(?I = 231)

(n = 95)

(n = 96)

(n = 50)

(n = 59)

96.8

94.8

92.0

93.2

3.2

5.2

8.0

6.8

Distal

(n =

1,109)

Inlays

81.7

77.5

74.8

81.0

2.7 0.2

3.1 0.5

4.3 0.5

4.8

15.4

19.0

20.4

14.3

Single crowns

Fixed p&al

Mesial

Distal

(n = 111)

(fa = 109)

Adequate Inadequate Lack of marginal integrity

62.2

48.6

68.5

69.1

31.5

39.6

25.2

24.5

Margins do not follow contour of tooth Gingival overhang

0.9

0.9

0.9

0.9

5.4

9.9

5.4

5.5

Buccal (?I f

Ill)

Lingual (n = 110)

(2) the validity of the quality measures. The present sample is not representative of the general population in the community. Instead, it consists of a group of people who are well educated and, perhaps, more sensitive to issues of dental health because of their occupations and place of employment. Establishing the validity of the quality measures depends, in part, on gaining professional consensus that what was measured was in fact quality. In this respect the quality criteria used are probably not at issue, since they are similar to those published by several other investigators.“‘. ” Further, the examiners in the present study are full-time faculty members with many years of clinical experience as teachers and providers of care. If any bias exists, the three examiners may be more severe in their ratings than nonacademic dentists. The important point is that considerable caution must be exercised in generalizing from this study to a larger population. With these limitations, perhaps the most striking finding of this study is the generally high quality of care seen in most of the routine restorative procedures. At least 75% to 90% of amalgam and synthetic restorations were rated as acceptable for each criterion. Since these two services constitute about 93% of all restorative services performed in general dental

THE JOURNAL

OF PROSTHETIC

DENTISTRY

denture abutments

-

Composites

Distal

Buccal

Lingual

Me&l and Distal

(n 3 79)

(?I * 86)

(n = 64)

(n = 202)

73.3

65.8

70.9

71.4

85.6

24.5

29.1

26.8

27.4

9.9

Mesial (?I I

86)

1.0

2.3

5.1

2.3

1.2

3.5

practice, it seems safe to conclude that, in this sample, most patients received adequate restorative care.15 Amalgams/composite restorations. The quality problems that exist with amalgam and composite restorations relate mainly to cavosurface margins. For the occlusal and proximal cavosurface margins, most inadequacies involved margins which were fractured or pitted. As many other investigators have shown, marginal breakdown of amalgams and composites occurs over a period of time.“‘-” Some of the breakdown may relate to improper use of materials, poor cavity preparation, or length of time that the restoration has been in service. This study did not have access to data on the length of time each restoration was in the mouth, so these two interrelated causes of marginal breakdown, operator technique and limitations in materials, cannot be differentiated. For amalgam gingivocavo surface margins, the major quality problem was related to gingivaf overhangs. About 20% of the amalgams had surfaces which were rated as inadequate for this criterion. It is interesting that several other studies from different parts of the world have reported similar findings.“-” As seen in Table VIII, with one exception, the

573

GRASSOETAL

Table

V. Rating of proximal

embrasures

and contours

(percentages)

Amalgams

Adequate Inadequate Do not conform to natural contour of tooth

Inlays

Mesial (n < 957)

Distal (n = 1,016)

Mesial (n = 95)

Distal (n = 94)

Mesial (n = 248)

Distal (n = 203)

85.6

83.0

97.9

100

89.5

88.7

11.7

14.0

2.1

10.5

11.4

Single crowns

Adequate Inadequate Do not conform to natural contour of tooth

Fixed partial denture abutments

Me&al (n = 110)

Distal (?I = 110)

Buccal (n = 107)

Lingual (n = 108)

Mesial (n = SO)

Distal (n = 79)

Buccal (n = 80)

Lingual (n = 85)

70.0

70.0

67.3

70.4

75.0

67.1

78.7

72.9

30.0

30.0

32.7

29.6

25.0

32.9

21.3

27.1

Table VI. Rating of marginal

ridges

(percentages)

Amalgams

Adequate Inadequate Not same height as adjacent marginal ridge Not in contact proximally with adjacent tooth Proximal contact not just below height of marginal ridge

Inlays

Fixed partial denture abutments

Single crowns

Mesial (n = 942)

Distal (n = 983)

Mesial (n = 55)

Distal (n = 87)

Mesial (n = 100)

Distal (n = 96)

Mesial (n = 45)

Distal (n = 40)

88.2

86.2

98.9

98.9

93.0

88.5

93.3

90.0

8.4

9.4

1.1

1.1

5.0

9.3

6.7

10.0

2.6

3.4

2.0

2.0

1.9

2.1

1.0

1.0

percentages of adequate restorations ranged from 73% to 87%. As these studies were done in different parts of the world, with different examining techniques, these results are remarkable in their similarity. Inlays. The quality scores for inlays were uniformly high for all quality categories. Because inlays involve a relatively difficult operative procedure, these high results were surprising. The high quality may relate to the superiority of the material, or perhaps patients who can afford to have inlays tend to go to dentists who have special expertise in this procedure. Whatever the explanation, the small number of inlays in the sample limits the generaliza-

574

Composites

tions which might be made. More studies are needed to support these findings. Crowns and abutments. While amalgams, composites, and inlays appear to be of adequate quality, the data on crowns and abutments are decidedly different. From 30% to 50% of the gingivocavo surfaces were rated as inadequate because of margins which had catches or deficiencies. Other common failures of crowns were overcontoured bulk and inadequate embrasures. These types of inadequacies are not unique to this sample. In a study of insurance company employees, Bailit and Raskin’ also found that crowns were the most deficient restoration. The reasons for the high percentage of inadequate

NOVEMBER 1979

VOLUME42

NUMBER5

RESTORATIVE

DENTAL

CARE

20

0

10

20

30

40

50

60

Fig. 1. Distribution of the average percentage of restorations/person gingivocavo surface margins.

crowns compared to other restorations are not known but could relate to several factors. First is the obvious fact that cast gold restorations involve a much more complex and difficult set of procedures than amalgams or composites. Second, the dentist’s dependence on a dental laboratory technician for a critical part of the process is certainly an important source of error. Another factor could be the frequency with which crowns are placed in most dental practices. If, for example, a practice profile involves less than 100 crowns per year, there may be a real question as to whether or not the average practitioner could maintain a high level of skill in this discipline. There is ample evidence in medicine that the frequency with which certain highly complex surgical procedures are performed is directly related to postoperative morbidity and mortality.“’ The same relationship between morbidity and frequency of performance of a specific procedure may hold true for dental care. The economic constraints on the dentist and patient are also a consideration. By the time a cast restoration comes back from the laboratory, the dentist has incurred a financial debt both in time and laboratory charge. If the crown is technically

THE JOURNAL

OF PROSTHETIC

DENTISTRY

70

80

90

rated inadequate

for

Table VII. Pontic adequacy Percent adequate bn * w Accumulation areas accessto cleaning Occlusion

Allows

56.8 52.3 97.7

deficient, the additional chair time and laboratory charges to remake the crown result in a major financial loss to the dentist. Under these circumstances, it would be reasonable to expect that many dentists might compromise at times and insert a less than adequate crown. Finally, the problem of adequately training dental students in complex crown and fixed partial denture techniques must be considered. In most dental schools, students seldom complete 20 crowns before graduation, either as single units or as abutments for fixed partial dentures.” It is difficult to believe that even the most skilled student could be considered proficient in the construction of crowns with this limited experience. Most likely, all these factors contribute to the high percentage of inadequate

575

GRASS0

Table VIII. Percent of amalgams

rated adequate

by quality

ET AL

category

Study

Subjects

?I

Occlukal and proximocavo surface margins

Bailit dnd associates Grass0 and associates Gilmore and associates Leon

Blue Cross/Blue Shield of Greater New York employees Univ. Connecticut Health Center employees New Mexico residents

163

73

73

84

76

291

81

82

86

88

Alexandei Bjorn and associates Bjom and associates

Royal Air Force personnel, Great Britain Dental students, dental school staff and patients, London Dental school patients, Sweden Shipyard workers, Sweden

Gingivocavo surface margins

Embrasures contour

1,763

74

543

84

400

87

225

42*

1,431

74*

Marginal ridges

*Defect L 0.2 mm.

crowns and bridge abutments. the number of pontics in the sample was quite small, almost 50% of them were inadequate. Problems of pontic design wtre associated with improper contour which resulted in accumulation of debris and poor access to mechanical cleansing. Many of the reasons cited for inadequacies in crown construction probably also apply to pontics, since they are related procedures. However, there is another factor that may be unique to pontics. That is, the cl&.anliness of the pontic is a function of both design and the patient’s oral hygiene practices. Of the two, oral hygiene is the most important. Thus, there may be little the dentist can do through pontic design to substantially alleviate problems of food and debris accumulations around pontics for certain patients.

ratings

for single

Pontics. Although

QUALITY ASSURANCE IMPLICA-fIONS

POLICY

For amalgams and composites, major improvements in treatment quality will be difficult to achieve because the ratings are already quite high. That is, since most restorations are already considered adequate (80% or more of the time) there is relatively little room for further improvement. Additional insights into this problem may be obtained using, as an example, the data on amalgam gingivocave surface margins. Table VIII shows that the percentage of amalgams rated inadequate for this quality category is surprisingly similar in Several studies. This could be interpreted to mean that the

576

average well-trained dentist will always make a certain percentage of errors inserting amalgams. These errors may result from the .normal pressures of dental practice, coupled with limitations in the techniques and materials used in amalgam restorations. The errors are probably not related to the training dentists receive, since the same inadequacy level is seen in so many different parts of the world. Further evidence for this conclusion is seen in Fig. 1, which presents the distribution of the average percentage of inadequate ratings per person for gingivocavo surface margins. There is relatively little variation among subjects: 75% of the people have less than 25% inadequate ratings, and the median percentage of inadequate ratings is only 9.2%. Assuming that these patients receive their care from different dentists, these data suggest that there is relatively little room for improvement for about 75% of the dentists. Our thesis, then, is that for most dentists, deficiencies in gingivocavo surface margins are the result of the normal conditions of practice and that this levei of error is so low that it should not be a cause for concern. Indeed, an argument could be made that attempts to reduce this error level through quality review systems would, overall, reduce the health of patient populations. This is due to the substantial cost of the review system. This money could be better used to generate more dental care for a greater number of people. Also, significant improvements in quality may require dentists to work more slowly, resulting in fewer restorations to fewer patients and

NOVEMBER

1979

VOLUME

42

NUMBER

5

RESTORATIVE

DENTAL

CARE

higher unit prices for restorations. In essence, society may have to accept a trade-off between a certain level of technical quality and oral health. Superb quality for relatively few people could result in reduced oral health levels for the population in general. To effect a meaningful increase in the percentage of gingivocavo surface margins rated as adequate for the majority of dentists, it may be necessary to look for advances in the materials and techniques used in the insertion of amalgam restorations. It is unlikely that quality review systems will have much effect. The small percentage of patients with greater than 25% overhangs represents another type of problem. They are receiving a level of care below what can be reasonably expected, and for the dentists treating these patients a quality assurance system might be of value. The key problem is developing an inexpensive method of identifying these dentists and then helping them to improve their treatment skills. The problem of inadequate crowns, fixed partial denture abutments, and pontics may also be difficult to deal with through a quality assurance system. While there is ample room for improvement, the basic difficulties with these services ,are structured into the present system for delivering dental care. That is, most dentists do not have a dental laboratory technician in their office who they can supervise closely to ensure proper crown construction. Many dentists probably do not construct enough cast gold restorations each year to keep their skills at the highest level or to develop a close working relationship with a laboratory. Further, many dentists may be unwilling to assume the financial losses incurred by remaking crowns or to charge fees which reflect a reasonable percentage of failures. There is obviously no single solution for improving the quality of cast gold restorations. Those that are available are controversial because they require a change in the existing practice structure. Recognizing the difficulties of bringing about any meaningful change, it is nevertheless important to at least make some positive suggestions. It is our position that major improvements in the quality of cast gold restorations may require that most of these services be done by a limited number of dentists who have advanced training in crown and fixed partial denture construction and have the volume of work to support their own dental technician or to develop a meaningful relationship with a dental laboratory. In addition, patients and insurance companies must be persuaded to accept at least part of the laboratory

THE JOURNAL

OF PROSTHETIC

DENTISTRY

and dental costs for remaking crowns. This is already true in medicine, where a patient is expected to pay all of the charges for additional operations and services resulting from the failure of the original operation. As with amalgams and composites. there is probably a small group of dentists for whom the quality of cast gold restorations is so poor that it is below what can be reasonably accepted, even considering all the problems just discussed. For those dentists a quality review system would be of value. CONCLUSIONS This study investigated the quality of restorative care in a group of health center employees. With limitations in sample size, representativeness of the sample, and methods of measuring quality clearly recognized, the results of the study suggest that significant improvements in the quality of amalgams, synthetic restorations, crowns, fixed partial denture abutments, and pontics will probably require advances in the science and technology of dentistry and modifications in the present system for delivering dental care. The impact of a quality review system is unlikely to affect the care provided by the majority of dentists. Quality review should play a role in monitoring the services of the small percentage of dentists whose care is ~CTI: inadequate. Admittedly, these conclusions are speculative and are not based on a large body of experimental information. Nevertheless, the evidence that is available is suggestive, and the development of a national policy to monitor the quality of dental care must consider what can be reasonably achieved with a quality assurance system. REFERENCES 1.

2.

3,

4. 5.

6.

Bellin, L. E., and Kavaler, F.: Policing publicly funded health care for poor quality, o&r-utilization and fraud-The New York City Medicaid experience. ,4m J Public Health 60:811, 1970. Bagramian, R. A., Jenny, J., Woodbury, P. J, and Proshek, B.: Quality assessment of restorations in a population of school children. Am J Public &zalth 65:397, 197.5. Cons, N. C.: Method for posttreatment evaluation of the quality of dental care. J Public Health Dent. 31:104. 1971. Ryge, G., and Snyder, M.: Evaluating the clinical quality of restorations. J Am Dent Assoc 87:369. 1973. Bailit, H. L., and Raskin, M. N.: Assessing quality of care and oral health in a population with dental insurance. Inquiry 15:359, 1978. Leon, A. R.: Amalgam restorations and periodontal disease. Br Dent J 140:377. 1976.

577

GRASS0

7. Bjorn, A. L.,. Bjorn, H., and Grkovic, B.: Marginal fit of restorations and its relation to periodontal bone level. Part I. Metal fillings. -0dont Revy 2Ctr311, 1969. a. Bjom, A. L.: Dental health in relation to age and dental care. Odontol Revy 25:45, Supplement 29, 1974. 9. Bailit, H. L., Koslowsky, M., Grasso, J., Holzman, S., Levine, P., and Atwood, P.: Quality of dental care: I. R., Vail&o, Development of standards. J Am Dent Assoc 89:842, 1974. 10. Alexander, A. G.: Periodontal aspects of conservative dentistry. Br Dent J 125:111, 1968. Ii. Gilmore, N., and Sheiham, A.: Overhanging dental restorations and periodontal disease. J Periodontol 42:8, 1971. 12. Milgrom, P. D., Weinstein, P., Ratener, P., Reed, W. A., and Morrison, K.: Dental examinations for quality control: Peer mview versus self-assessment. Am J Public Health 68:394, 1978.

13. Quality Evaluation for Dental Care: Guidelines for the Assessment of Clinical Quality and Professional Performance. California Dental Association, Los Angeles, 1977. 14. Cons, N. C.: Clinical ‘Evaluation of Medicaid Patients in New York State, National Dental Health Conference, ed. 23, April 24-26, 1972.

ET AL

15. Bailit, H. L., and Raskin, M. N.: Unpublished data from Blue Cross and Blue Shield of Greater New York, 1978. 16. Mahler, D., and Marantz, R.: The effect of time on the marginal failure behavior of amalgams. J Oral Rehabil, 1979 (In press). 17. Barnes, J., Carter, H., and Hall, J.: Causative factors resulting in the placement of dental restorations: A survey of 8,891 restorations. Milit Med 138:736, 1973. 18. Mahler, D., Terkla, L., and Van Eysden, J.: Marginal fracture of amalgam restorations. J Dent Res 52:823, 1973. 19. Donabedian, A.: Evaluating the quality of medical care. Milbank Mem Fund Q 44:166, 1966. 20. Dental Education in the United States, Council on Dental Education of the American Dental Association, Chicago, 1977, pp. 159-173. Reprint requeststo: DR. JOSEPH Grwsso UNIVERSITY OF CONNECTICUT SCHOOL OF DENTAL MEDICINE FARMINGTON, CONN. 06032

ARTICLES TO APPEAR IN FUTURE ISSUES Flexural properties of denture base polymers I. Eystein

Ruyter,

Dipl.

Chem.,

Dr. Rer. Nat.,

and Svend A. Svendsen,

Development, utilization, and evaluation of educational patients with maxillary and mandibular defects Timothy

R. Saunders,

Cand.

programs for

D.D.S.

Maxillary reshaping prostheses: Effectiveness in improving swallowing of postsurgical oral cancer patients Rokrt

L. Wheeler,

Real.

D.D.S.,

Jeri A. Logemann,

Ph.D., ‘and Morton

speech and

S. Rosen, D.D.S.

The etiology, diagnosis, and treatment of TMJ dysfunction-pain Part I: Etiology Lawrence

A. Weinberg,

D.D.S.,

syndrome.

M.S.

NOVEMBER

1979

VOLUME

42

NUMBER

5

The quality of restorative dental care.

The quality of restorative dental care Joseph E. Grasso, D.D.S., M.S.,* John Nalbandian, Howard Bailit, D. M. D., Ph.D. * * * * University of Connect...
721KB Sizes 0 Downloads 0 Views