- Email: [email protected]
Distribution of acid-etched, fixed, and removable prostheses in dental patients
LAURELL,
Table V. Test of differences left sides
WHITACRE,
AND
STIEG
Williamson EH, Wilson CW: Use of a submental-vertex analysis for producing quality temporomandibular joint radiographs. Am J Orthod 70~200, 1976. 3. Lysell L, Petersson A: The submento-vertex projection in radiography of the temporomandibular joint. Dentomaxillofac Radio1 9:11, 1980. 4. Weinberg LA: Technique for mandibular joint radiograph. J
in right from
2.
Variable
Mean difference (“)
Probability (p)
Condylar width Alpha angle Beta angle Gonial angle Long axis angle
0.1 mm -3 2 2 0
,914 ,004 ,132 .018 .781
PROSTHET DENT 28:284,
5.
6.
CONCLUSIONS 1. A positive correlation exists between the angle formed by the inferior border of the mandible to the midsagittal plane and the condylar long axis. The submental-vertex projection, however, remains the most accurate indicator of the condylar long axis angulation. 2. Although the median condylar long axis angle was 17 degrees for the subjects studied, the wide variability between individuals indicates that radiographic views of the TMJ should not be made by using averaged angulation settings. 3. A significant mandibular asymmetry exists in the population st.udied. REFERENCES 1. Beckwith PJ, Monfort DR, Williams BH: Accurate depth of cut in temporomandibular joint laminographs. Angle Orthod 50:16, 1980.
7. 8. 9. 10. 11. 12.
1972.
Farrar WB, McCarty WL: A Clinical Outline of Temporomandibular Joint Diagnosis and Treatment, ed 7. Montgomery, Ala., 1982, Normandie Publications, pp 93-99. Petri G, Arduino A, Pera P: Consistency of performance of a new craniostat for oblique lateral transcranial radiographs of the temporomandibular joint. J PROSTHET DENT 52~270, 1984. Ricketts RM: Present status of laminography as related to dentistry. J Am Dent Assoc 65:56, 1962. Updegrave WM: Temporomandibular articulation: X-ray examination. Dent Radiogr Photogr 26:41, 1953. Shore NA: The interpretation of temporomandibular joint roentograms. Oral Surg Oral Med Oral Path01 52:426, 1984. Winer BJ: Statistical Principles in Experimental Design, ed 2. New York, 1971, McGraw-Hill Book Co, p 283. Yale S: Radiographic evaluation of the temporomandibular joint. J Am Dent Assoc 79:102, 1969. Eckerdal 0, Lundberg M: Temporomandibular joint relations as revealed by conventional radiographic techniques. Dentomaxillofat Radio1 8:65, 1979.
Reprint requests to: DR. KIM LAURELL OHIO STATE UNIVERSITY COLLEGE OF DENTISTRY COLUMBUS. OH 43210-1241
Distribution of acid-etched, fixed, and removable prostheses in dental patients Finn Gustavsen, University
D.D.D.,
of Connecticut
Health
Dr.Odont., Center,
M.P.H.,*
School of Dental
and Ralph V. Katz, D.M.D., Medicine,
T
he growing awareness of the aging of populations in developed nations and the recently observed decline in caries prevalence in younger age groups’-4 reinforces the appropriateness of establishing baseline oral health data for the adult age groups. The shift of the dental profession’s interest to the oral health of middle-aged *Assistant Professor and Chief, Fixed Prosthodontic Services. **Associate Professor and Head, Department of Restorative Dentist‘Y. 374
Farmington,
Ph.D.**
Conn.
and older adult populations reflects society’s commitment to better understand the problems and needs of these age groups. Epidemiologic data on the present tooth replacement pattern in adult populations are essential to permit planning and useful interpretation of future studies on adult oral health. These data are of particular interest for the planning and conducting of studies concerning decay rates and periodontal problems associated with dental prostheses. In addition, descriptive studies of the MARCH
1987
VOLUME
57
NUMBER
3
DISTRIBUTION
OF PROSTHESES
IN DENTAL
PATIENTS
“SLICE OF LIFE” RESEARCH PROJECT Dental Society - UCONN School of Dental Medicine
Hartford Year 01 Birth:
Sex:
NUMBER OF TEETH OR MISSING
Female Male
PRESENT
2 1
NUMBER
Visits:
On a Regular Basis Occasionally Only When In Paln
OF MISSING TEETH REPLACED BY
2 -i :: _
NUMBER OF MISSING TEETH NOT REPLACED R.DI.CI.bl4
NO, R.d.C..bl.
Fig. 1. Data collection form used in study.
current tooth replacement patterns provide data on one aspect of the total information required by dentists to rationally determine the magnitude of the unmet need for prosthodontic care in adult populations. Although behavioral scientists and economists will have to make contributions to provide a complete picture of the unmet need and demand for dental prostheses, descriptive epidemiologic data of current tooth replacement patterns provide a baseline that can be used for present assessment as well as for future retrospective comparisons. METHODS
AND MATERIAL
A data collection form was developed on tooth mortality and prosthodontic replacements for use by dentists in their office (Fig. 1). The form grouped teeth by molars, premolars, canines and incisors for the maxillary and the mandibular archs. Dentists were requested to complete all items for each tooth type in each arch, including number of: (1) teeth present, (2) teeth missing, (3) teeth replaced by conventional or acid-etched cast fixed partial dentures, and (4) teeth replaced by removable prostheses. Dentists also recorded the age and sex of the patient and whether the patient visited the dentist regularly, occasionally, or for emergency reasons only. In addition, dentists indicated, using their own professional judgement, whether space was available or not available for a replacement, given that a tooth was missing. Although more uniformly defined criteria were considered for use during the planning phases of the project, no set of easily described criteria were found that could comprehensively evaluate the multitude of factors that determined this THE JOURNAL
OF PROSTHETIC
DENTISTRY
clinical judgment. Therefore, it was decided to allow each dentist to use personal judgment and to rely on the random selection of practitioners to provide interpretable data that could be considered typical of all general practitioners. Moreover, it was not clear that an arbitrary and uniformly applied definition of “no space available” would be as meaningful an interpretation of the collected data as allowing the dentists to express their own judgment, which had already exerted a great influence on determining the present replacement pattern in their own patients. A 15% sample of members in the Hartford Dental Society were randomly selected from a membership list of general practicing dentists. Each selected member was contacted by telephone and asked to participate. If one of the randomly selected names was either deceased or no longer in practice in the Hartford area, another randomly selected member was chosen. Each participant was asked to complete all items on the data collection form on all patients 20 years of age and older for a l-week period. Three sets of sample patients and mock forms with accompanying instructions and explanations were mailed to each participating dentist to familiarize them with the data form. In addition, dentists were reminded that any selectivity on their part regarding which patients to include would lead to an unrepresentative sample and jeopardize the value of the data. A professional courier service delivered 120 blank data collection forms to each office on a given day in April, 1983 and on the following Monday, the data collection was initiated in all offices and continued for a B-day period. 375
GUSTAVSEN
AND
KATZ
Table II. Mean number of missing teeth + standard deviation in each arch within age group Arch
40.49
30.39
20.29
50.59
Age groups
q
Without
[7
With
60.69
70+
20 30 40 50 60 70 20
Total
(yrs.)
Maxillary
Mandibular
+ -
0.71 k 1.49 1.37 + 2.80 2.48 k 3.82 3.41 t 3.94 5.53 f 4.93 7.1625.22 2.81 + 4.11
0.70 f 1.25 1.13 f 1.92 1.95 k 2.68 2.90 k 3.14 3.85 f 3.66 5.83k4.63 2.23 + 3.13
29 39 49 59 69 70+
Total 1.41 + 2.37 2.50 k 4.36 4.43 + 6.14 6.31 -t- 6.47 9.38 _+ 7.87 12.99+9.14 5.04 t 6.79
space space
Fig. 2. Proportion of missing teeth with and without space for replacement by arch within age groups.
Table I. Age and sex distribution
of patients
Men
Women
Age (yrs)
N
%
N
%
20-29 30-39 40-49 50-59 60-69 70+ Total
157 235 174 145 143 52 906
43.7 43.8 47.2 42.2 50.9 32.9 46.5
102 302 195 199 138 106 1042
56.3 56.2 52.8 57.8 49.1 67.1 53.5
The completed data forms were collected from each office by a courier. The data forms were hand checked for completeness and legibility before keypunching and analysis of the data. RESULTS Of the randomly selected 15% of general practicing dentists who were members of the Hartford Dental Society (n = 47), 94% agreed to participate. Of the 44 dentists who agreed to participate, 42 completed all aspects of the study. Thus, of the original randomly selected sample of dentists in the greater Hartford area serving a population of approximately 850,000 people, 89.4% participated in this study. All offices collected the data during the designated week in April except for two dentists whose vacation schedule resulted in the collecting of their data during the following week. Completed data forms were obtained from the 42 dental practices on 2069 patients 20 years old and older who were seen during the data collection week. The dentists on the average worked 4.5 days during that week and saw an average of 10.9 patients per working day. Nearly 80% of the patients were categorized by their dentist as regular users of dental care and 18% were 376
Age
identified as occasional users of dental care. Only 2% were classified as only emergency users of dental care. The age and sex distribution of the 94% of patients for whom complete age and sex data were obtained are given in Table I. The largest proportion of patients were in the group 30 to 39 years of age, with relatively even distribution in 20-, 40-, and 50-year olds. As can be seen in Table I, there were slightly more women than men in nearly all of the age groups. Overall, the mean age was 45.4 years, with 53.5% of the subjects identified as women. The mean number of missing teeth in each arch for each age group ranged from a low of 1.41 for 20 to 29-year-olds to a high of 12.99 for patients 70 or more years old (Table II). The maxillary arch showed a higher mean number of missing teeth than the mandibular arch for each age group. For the overall population, 92% of patients were dentulous in both arches, 6% had teeth in only one arch, and 2% were totally edentulous. All the edentulous patients were more than 40 years of age. On the average for the total study group, approximately 10% of the missing teeth were categorized as having no space available for replacement. The proportion of missing teeth that lacked available space for replacement varied with age, being markedly higher in the younger age groups (Fig. 2). The percent of nonreplaceable missing teeth also differed among tooth types. The highest percent of nonreplaceable missing teeth was found for premolars (15X), followed by molars (lo%), incisors (3%), and canines. In assessing the tooth replacement rate, only missing teeth that had space available for replacement were considered. The replacement rates by tooth types within age groups are given in Fig. 3. Molars and premolars showed the lowest percentage of replacement in both arches for each age group. The proportion of replaced teeth increased with age for both molars and premolars. On the other hand, the replacement rate for incisors and canines was very high in all age groups. The pattern for all teeth (Fig. 3) is similar to the patterns demonstrated MARCH
1987
VOLUME
57
NUMBER
3
DISTRIBUTION
OF PROSTHESES
Fig.
within
IN DENTAL
3. Replacement age groups.
Table III. Percent and number both arches combined
PATIENTS
rates for missing
teeth that had space available
of replaced teeth by type of replacement
by tooth types
within
age groups for
Age group
Total
Prosthesis
‘20 to 29 (n = 93)
30 to 39 (II = 647)
40 to 49 (n = 984)
50 to 59 (n = 1372)
60 to 69 (n = 2097)
70+ (n = 1694)
(n = 6887)
Fixed conventional Acid-etched cast Removable
34.4% 8.6% 57.0%
24.6% 0.4% 75.0%
17.4% 0.9% 81.7%
22.2% 0.7% 77.1%
9.1% 0.1% 90.8%
5.4% 0.7% 93.9%
13.8% 0.6% 85.6%
n = Number
of replaced
teeth
by the molars and premolars and reflects the disproportionate contribution by the posterior teeth to overall tooth loss. The number of missing teeth replaced by a conventional fixed partial denture, by an acid-etched cast fixed partial denture, or by a removable prosthesis varied between age groups (Table III). Overall, fixed partial dentures contributed 14.4% to the total replacement of teeth, of which acid-etched fixed partial dentures contributed approximately 0.6% and conventional partial dentures the remaining 13.8%. Removable prostheses replaced the most number of missing teeth (approximately 85.6% for the whole population). Acid-etched cast fixed partial dentures were used more often in the maxillary arch than in the mandibular arch. Specifically, given that teeth were replaced, the acid-etched fixed partial denture was the prosthesis of choice for 0.7% of the replaced teeth in the maxillary arch and 0.4% of the replaced teeth in the mandibular arch. In addition, it was observed that acid-etched cast fixed partial dentures replaced slightly more teeth in the posterior regions (55%) than in the anterior regions (45%). THE JOURNAL
OF PROSTHETIC
DENTISTRY
The proportion of the different types of replacements by age groups for each arch is illustrated in Fig. 4. Although the percentage of missing teeth replaced by a fixed prosthesis (acid-etched and conventional) constituted about 14% of all replaced teeth, this percentage decreased with age. In the 20- to 29-year-old age group, fixed partial dentures constituted nearly 40% in the maxillary arch and 75% in the mandibular arch. Given that a fixed prosthesis was used, the acid-etched fixed partial denture was used to replace missing teeth most often in the youngest (20%) and oldest (13%) age groups. For all other age groups, acid-etched fixed partial dentures replaced no more than 5%, at most, of the missing teeth replaced by fixed prostheses.
DISCUSSION The favorable percentage of participation, through the willingness of the members of the Hartford Dental Society to cooperate in the study, is of major importance
for the representativity of the data. Whether any adult patient during the actual week was not registered is not known. However, the number of adult patients seen by 377
GUSTAVSEN
Max.
Mand.
20.29
30.39
40.49 50.59 60.69 Age group (yrs.)
70+
Total
Fig. 4. Distribution of type of prosthesis by arch within age groups. lZi = Conventional fixed partial denture; 0 = removable denture; = acid-etched fixed partial denture.
the dentists per working day indicates that the proportion of nonregistered patients was probably 10w.~ Both the number of patients reported and the high overall compliance exhibited by the participating dentists suggest that the data collected has a low probability of selection bias. The simplicity of the data form clearly served to reduce recording errors as revealed by internal cross-checks on the data form itself. The illogical, and hence detectable, error rate was less than 2%. The rate of replacement for replaceable missing teeth was highest in the upper age groups. Interestingly, data from a national population survey also shows the highest percentage of adult individuals needing fixed partial dentures, partial removable dentures, or both, in groups below 65 years of age whereas the percentage was lower for those above 65 years of age.6 The differences in replacement rates between age groups in the present study was almost exclusively a result of differences between replacement rates for molars and premolars, inasmuch as the rates for canines and incisors were high in all age groups. The figures indicate that there may be an unmet need for the replacement of molars and premolars, depending on the philosophy guiding the treatment as to what extent all missing teeth should be replaced. This notion is in accordance with the conclusion recently made that there is a substantial unmet need for fixed and removable dentures.’ Compared with corresponding figures from studies of patient groups from the Scandinavian countries’,’ the U.S. figures tend to show higher replacement rates for premolars and molars for regular dental care users. Differences in the willingness to tolerate open premolar and molar spaces, economic factors, or differences in professional standards are possible reasons that may explain the cross-cultural differences in replacement rates. The relative proportion of the different replacements shows that the fixed partial prostheses contributed 378
AND
KATZ
only a small share to the total replacements in the present study. Although the ratio of the number of teeth replaced by removable:fixed prostheses is 19:1 for 60 to 69-year-olds, care should be taken not to misinterpret this ratio as representing a ratio of patients with fixed or removable prostheses. This 19:l ratio, based on the 60 to 69-year-old age group data from Table III, refers only to replaced missing teeth. Quite clearly, the choice to use a removable prosthesis is influenced by many factors (financial as well as intraoral factors) and will tend to be used for patients requiring the replacement of many teeth in one arch. Thus, the ratio of patients with removable:fixed prostheses would be considerably less than 19:l. Comparison with Norwegian data9 from 35to 45-year-old dental patients indicates a similar removable:fixed prosthesis ratio (approximately 3:l) in the corresponding U.S. age groups. It should be noted that although the percentage of fixed partial denture replacements in the youngest age group is relatively high, the absolute number of replacements in this age group is low. The finding that the youngest and oldest age groups showed the highest use of acid-etched fixed partial dentures (20% and 13% of fixed partial denture use) may indicate future trends for the special intraoral conditions exhibited by these two age groups. It may also be seen as an early indication of an increasing overall use of acid-etched cast fixed partial dentures, given that this technique was virtually unknown a decade ago. SUMMARY This report describes the pattern of tooth replacement for a random sample of adult dental patients in a major urban area in the northeastern United States. The data were collected by using a practitioner-based epidemiologic monitoring system that had been established with the local dental society. Nearly 90% of the randomly selected dentists collected the data on all adult patients seen during a l-week period. The 2069 patients examined were predominantly regular users of dental care with a relatively even distribution across lo-year age groups. There was a slight preponderance of women in the sample (55%). There were no significant differences between men and women in terms of mean numbers of missing teeth. Overall, 92% were dentulous in both arches, 6% were edentulous in one arch, and 2% were totally edentulous. When the space was available for replacement, molars and premolars showed the lowest percentages of replacement in both arches for each age group. Overall, 14.4% of the replaced teeth were replaced by a fixed partial denture, of which acid-etched fixed partial dentures contributed 0.6% and conventional fixed partial dentures the remaining 13.8%. Removable prostheses replaced 85.6% of the missing teeth. The proportion of fixed replacements was highest in the MARCH
1987
VOLUME
57
NUMBER
3
DISTRIBUTION
OF PROSTHESES
IN DENTAL
PATIENTS
caries in New Zealand. J Dent Res 1961(Special issue):1327,
youngest age groups and the proportion of removable replacements was dominating in the older age groups. Acid-etched fixed partial dentures were found most frequently in the youngest and oldest age groups.
1982. American Dental Association, The Bureau of Economic and Behavioral Research. The 1984 Survey of Dental Practice: Patient Visits to the Dentist. Chicago, 1984, ADA. Institute of Medicine: Division of Health Care Services Public Policy Options for Better Dental Health: Report of a Study, IOM Pub. No. 80-86. Washington, D.C., 1980, National Academy Press. Douglass CW: The role of specialists and general practitioners in provision of prosthetic services. J PROSTHET DENT 40~844, 1984. Bjorn AL, Oval1 B: Partial edentulism and its prosthetic treatment. A frequency study within a Swedish population. Swed Dent J 3:15, 1979. Gustavsen F, Silness J: Tooth loss and tooth replacement among regular dental care users. J Dent Res 1962(Special issue):249, 1983 (Abstr. No. 720).
This is the second in a series of reports on this practicing dentist-based epidemiologic monitoring system on adult oral health referred to as the Slice-of-Life Project. The initial and sustained support of the leadership and membership of the Hartford Dental Society is acknowledged by the authors as critical to the quality of this collaborative research project.
REFERENCES 1. Brunelle JA, Carlos JP: Changes in the prevalence of dental caries in U.S. school children, 1961-1980. J Dent Res 1961(Special issue):1346, 1982. 2. Von der Fehr FR: Evidence of decreasing caries prevalence in Norway. J Dent Res 1961(Special issue):1331, 1982. 3. Koch G: Evidence for declining caries prevalence in Sweden. J Dent Res 1961(Specialissue):1340,1982. 4. Brown RH: Evidence of decrease in the prevalence of dental
Reprint
requests to:
DR. FINN GUSTAVSEN UNIVERSITYOF CONNECTICUTHEALTH CENTER SCHOLLOF DENTAL MEDICINE FARMINGTON,CT 06032-9984
Correction In the article “The effects of surface texture and grooving on the retention of cast crowns” (J PROSTHET DENT 1986;56:421-4), an error occurred in the last line of the Conclusions. It should
read: In contrast, there were no statistically significant differences in crown retention for zinc phosphate cement between grooved crowns with smooth and rough finish tooth surfaces and plain crowns with a smooth finish tooth surface. The only combination that is contraindicated for zinc phosphate cement is the plain crown with a rough surface finish. The authors regret the error.
THE JOURNAL
OF PROSTHETIC
DENTISTRY
379
Table V. Test of differences left sides
WHITACRE,
AND
STIEG
Williamson EH, Wilson CW: Use of a submental-vertex analysis for producing quality temporomandibular joint radiographs. Am J Orthod 70~200, 1976. 3. Lysell L, Petersson A: The submento-vertex projection in radiography of the temporomandibular joint. Dentomaxillofac Radio1 9:11, 1980. 4. Weinberg LA: Technique for mandibular joint radiograph. J
in right from
2.
Variable
Mean difference (“)
Probability (p)
Condylar width Alpha angle Beta angle Gonial angle Long axis angle
0.1 mm -3 2 2 0
,914 ,004 ,132 .018 .781
PROSTHET DENT 28:284,
5.
6.
CONCLUSIONS 1. A positive correlation exists between the angle formed by the inferior border of the mandible to the midsagittal plane and the condylar long axis. The submental-vertex projection, however, remains the most accurate indicator of the condylar long axis angulation. 2. Although the median condylar long axis angle was 17 degrees for the subjects studied, the wide variability between individuals indicates that radiographic views of the TMJ should not be made by using averaged angulation settings. 3. A significant mandibular asymmetry exists in the population st.udied. REFERENCES 1. Beckwith PJ, Monfort DR, Williams BH: Accurate depth of cut in temporomandibular joint laminographs. Angle Orthod 50:16, 1980.
7. 8. 9. 10. 11. 12.
1972.
Farrar WB, McCarty WL: A Clinical Outline of Temporomandibular Joint Diagnosis and Treatment, ed 7. Montgomery, Ala., 1982, Normandie Publications, pp 93-99. Petri G, Arduino A, Pera P: Consistency of performance of a new craniostat for oblique lateral transcranial radiographs of the temporomandibular joint. J PROSTHET DENT 52~270, 1984. Ricketts RM: Present status of laminography as related to dentistry. J Am Dent Assoc 65:56, 1962. Updegrave WM: Temporomandibular articulation: X-ray examination. Dent Radiogr Photogr 26:41, 1953. Shore NA: The interpretation of temporomandibular joint roentograms. Oral Surg Oral Med Oral Path01 52:426, 1984. Winer BJ: Statistical Principles in Experimental Design, ed 2. New York, 1971, McGraw-Hill Book Co, p 283. Yale S: Radiographic evaluation of the temporomandibular joint. J Am Dent Assoc 79:102, 1969. Eckerdal 0, Lundberg M: Temporomandibular joint relations as revealed by conventional radiographic techniques. Dentomaxillofat Radio1 8:65, 1979.
Reprint requests to: DR. KIM LAURELL OHIO STATE UNIVERSITY COLLEGE OF DENTISTRY COLUMBUS. OH 43210-1241
Distribution of acid-etched, fixed, and removable prostheses in dental patients Finn Gustavsen, University
D.D.D.,
of Connecticut
Health
Dr.Odont., Center,
M.P.H.,*
School of Dental
and Ralph V. Katz, D.M.D., Medicine,
T
he growing awareness of the aging of populations in developed nations and the recently observed decline in caries prevalence in younger age groups’-4 reinforces the appropriateness of establishing baseline oral health data for the adult age groups. The shift of the dental profession’s interest to the oral health of middle-aged *Assistant Professor and Chief, Fixed Prosthodontic Services. **Associate Professor and Head, Department of Restorative Dentist‘Y. 374
Farmington,
Ph.D.**
Conn.
and older adult populations reflects society’s commitment to better understand the problems and needs of these age groups. Epidemiologic data on the present tooth replacement pattern in adult populations are essential to permit planning and useful interpretation of future studies on adult oral health. These data are of particular interest for the planning and conducting of studies concerning decay rates and periodontal problems associated with dental prostheses. In addition, descriptive studies of the MARCH
1987
VOLUME
57
NUMBER
3
DISTRIBUTION
OF PROSTHESES
IN DENTAL
PATIENTS
“SLICE OF LIFE” RESEARCH PROJECT Dental Society - UCONN School of Dental Medicine
Hartford Year 01 Birth:
Sex:
NUMBER OF TEETH OR MISSING
Female Male
PRESENT
2 1
NUMBER
Visits:
On a Regular Basis Occasionally Only When In Paln
OF MISSING TEETH REPLACED BY
2 -i :: _
NUMBER OF MISSING TEETH NOT REPLACED R.DI.CI.bl4
NO, R.d.C..bl.
Fig. 1. Data collection form used in study.
current tooth replacement patterns provide data on one aspect of the total information required by dentists to rationally determine the magnitude of the unmet need for prosthodontic care in adult populations. Although behavioral scientists and economists will have to make contributions to provide a complete picture of the unmet need and demand for dental prostheses, descriptive epidemiologic data of current tooth replacement patterns provide a baseline that can be used for present assessment as well as for future retrospective comparisons. METHODS
AND MATERIAL
A data collection form was developed on tooth mortality and prosthodontic replacements for use by dentists in their office (Fig. 1). The form grouped teeth by molars, premolars, canines and incisors for the maxillary and the mandibular archs. Dentists were requested to complete all items for each tooth type in each arch, including number of: (1) teeth present, (2) teeth missing, (3) teeth replaced by conventional or acid-etched cast fixed partial dentures, and (4) teeth replaced by removable prostheses. Dentists also recorded the age and sex of the patient and whether the patient visited the dentist regularly, occasionally, or for emergency reasons only. In addition, dentists indicated, using their own professional judgement, whether space was available or not available for a replacement, given that a tooth was missing. Although more uniformly defined criteria were considered for use during the planning phases of the project, no set of easily described criteria were found that could comprehensively evaluate the multitude of factors that determined this THE JOURNAL
OF PROSTHETIC
DENTISTRY
clinical judgment. Therefore, it was decided to allow each dentist to use personal judgment and to rely on the random selection of practitioners to provide interpretable data that could be considered typical of all general practitioners. Moreover, it was not clear that an arbitrary and uniformly applied definition of “no space available” would be as meaningful an interpretation of the collected data as allowing the dentists to express their own judgment, which had already exerted a great influence on determining the present replacement pattern in their own patients. A 15% sample of members in the Hartford Dental Society were randomly selected from a membership list of general practicing dentists. Each selected member was contacted by telephone and asked to participate. If one of the randomly selected names was either deceased or no longer in practice in the Hartford area, another randomly selected member was chosen. Each participant was asked to complete all items on the data collection form on all patients 20 years of age and older for a l-week period. Three sets of sample patients and mock forms with accompanying instructions and explanations were mailed to each participating dentist to familiarize them with the data form. In addition, dentists were reminded that any selectivity on their part regarding which patients to include would lead to an unrepresentative sample and jeopardize the value of the data. A professional courier service delivered 120 blank data collection forms to each office on a given day in April, 1983 and on the following Monday, the data collection was initiated in all offices and continued for a B-day period. 375
GUSTAVSEN
AND
KATZ
Table II. Mean number of missing teeth + standard deviation in each arch within age group Arch
40.49
30.39
20.29
50.59
Age groups
q
Without
[7
With
60.69
70+
20 30 40 50 60 70 20
Total
(yrs.)
Maxillary
Mandibular
+ -
0.71 k 1.49 1.37 + 2.80 2.48 k 3.82 3.41 t 3.94 5.53 f 4.93 7.1625.22 2.81 + 4.11
0.70 f 1.25 1.13 f 1.92 1.95 k 2.68 2.90 k 3.14 3.85 f 3.66 5.83k4.63 2.23 + 3.13
29 39 49 59 69 70+
Total 1.41 + 2.37 2.50 k 4.36 4.43 + 6.14 6.31 -t- 6.47 9.38 _+ 7.87 12.99+9.14 5.04 t 6.79
space space
Fig. 2. Proportion of missing teeth with and without space for replacement by arch within age groups.
Table I. Age and sex distribution
of patients
Men
Women
Age (yrs)
N
%
N
%
20-29 30-39 40-49 50-59 60-69 70+ Total
157 235 174 145 143 52 906
43.7 43.8 47.2 42.2 50.9 32.9 46.5
102 302 195 199 138 106 1042
56.3 56.2 52.8 57.8 49.1 67.1 53.5
The completed data forms were collected from each office by a courier. The data forms were hand checked for completeness and legibility before keypunching and analysis of the data. RESULTS Of the randomly selected 15% of general practicing dentists who were members of the Hartford Dental Society (n = 47), 94% agreed to participate. Of the 44 dentists who agreed to participate, 42 completed all aspects of the study. Thus, of the original randomly selected sample of dentists in the greater Hartford area serving a population of approximately 850,000 people, 89.4% participated in this study. All offices collected the data during the designated week in April except for two dentists whose vacation schedule resulted in the collecting of their data during the following week. Completed data forms were obtained from the 42 dental practices on 2069 patients 20 years old and older who were seen during the data collection week. The dentists on the average worked 4.5 days during that week and saw an average of 10.9 patients per working day. Nearly 80% of the patients were categorized by their dentist as regular users of dental care and 18% were 376
Age
identified as occasional users of dental care. Only 2% were classified as only emergency users of dental care. The age and sex distribution of the 94% of patients for whom complete age and sex data were obtained are given in Table I. The largest proportion of patients were in the group 30 to 39 years of age, with relatively even distribution in 20-, 40-, and 50-year olds. As can be seen in Table I, there were slightly more women than men in nearly all of the age groups. Overall, the mean age was 45.4 years, with 53.5% of the subjects identified as women. The mean number of missing teeth in each arch for each age group ranged from a low of 1.41 for 20 to 29-year-olds to a high of 12.99 for patients 70 or more years old (Table II). The maxillary arch showed a higher mean number of missing teeth than the mandibular arch for each age group. For the overall population, 92% of patients were dentulous in both arches, 6% had teeth in only one arch, and 2% were totally edentulous. All the edentulous patients were more than 40 years of age. On the average for the total study group, approximately 10% of the missing teeth were categorized as having no space available for replacement. The proportion of missing teeth that lacked available space for replacement varied with age, being markedly higher in the younger age groups (Fig. 2). The percent of nonreplaceable missing teeth also differed among tooth types. The highest percent of nonreplaceable missing teeth was found for premolars (15X), followed by molars (lo%), incisors (3%), and canines. In assessing the tooth replacement rate, only missing teeth that had space available for replacement were considered. The replacement rates by tooth types within age groups are given in Fig. 3. Molars and premolars showed the lowest percentage of replacement in both arches for each age group. The proportion of replaced teeth increased with age for both molars and premolars. On the other hand, the replacement rate for incisors and canines was very high in all age groups. The pattern for all teeth (Fig. 3) is similar to the patterns demonstrated MARCH
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Table III. Percent and number both arches combined
PATIENTS
rates for missing
teeth that had space available
of replaced teeth by type of replacement
by tooth types
within
age groups for
Age group
Total
Prosthesis
‘20 to 29 (n = 93)
30 to 39 (II = 647)
40 to 49 (n = 984)
50 to 59 (n = 1372)
60 to 69 (n = 2097)
70+ (n = 1694)
(n = 6887)
Fixed conventional Acid-etched cast Removable
34.4% 8.6% 57.0%
24.6% 0.4% 75.0%
17.4% 0.9% 81.7%
22.2% 0.7% 77.1%
9.1% 0.1% 90.8%
5.4% 0.7% 93.9%
13.8% 0.6% 85.6%
n = Number
of replaced
teeth
by the molars and premolars and reflects the disproportionate contribution by the posterior teeth to overall tooth loss. The number of missing teeth replaced by a conventional fixed partial denture, by an acid-etched cast fixed partial denture, or by a removable prosthesis varied between age groups (Table III). Overall, fixed partial dentures contributed 14.4% to the total replacement of teeth, of which acid-etched fixed partial dentures contributed approximately 0.6% and conventional partial dentures the remaining 13.8%. Removable prostheses replaced the most number of missing teeth (approximately 85.6% for the whole population). Acid-etched cast fixed partial dentures were used more often in the maxillary arch than in the mandibular arch. Specifically, given that teeth were replaced, the acid-etched fixed partial denture was the prosthesis of choice for 0.7% of the replaced teeth in the maxillary arch and 0.4% of the replaced teeth in the mandibular arch. In addition, it was observed that acid-etched cast fixed partial dentures replaced slightly more teeth in the posterior regions (55%) than in the anterior regions (45%). THE JOURNAL
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The proportion of the different types of replacements by age groups for each arch is illustrated in Fig. 4. Although the percentage of missing teeth replaced by a fixed prosthesis (acid-etched and conventional) constituted about 14% of all replaced teeth, this percentage decreased with age. In the 20- to 29-year-old age group, fixed partial dentures constituted nearly 40% in the maxillary arch and 75% in the mandibular arch. Given that a fixed prosthesis was used, the acid-etched fixed partial denture was used to replace missing teeth most often in the youngest (20%) and oldest (13%) age groups. For all other age groups, acid-etched fixed partial dentures replaced no more than 5%, at most, of the missing teeth replaced by fixed prostheses.
DISCUSSION The favorable percentage of participation, through the willingness of the members of the Hartford Dental Society to cooperate in the study, is of major importance
for the representativity of the data. Whether any adult patient during the actual week was not registered is not known. However, the number of adult patients seen by 377
GUSTAVSEN
Max.
Mand.
20.29
30.39
40.49 50.59 60.69 Age group (yrs.)
70+
Total
Fig. 4. Distribution of type of prosthesis by arch within age groups. lZi = Conventional fixed partial denture; 0 = removable denture; = acid-etched fixed partial denture.
the dentists per working day indicates that the proportion of nonregistered patients was probably 10w.~ Both the number of patients reported and the high overall compliance exhibited by the participating dentists suggest that the data collected has a low probability of selection bias. The simplicity of the data form clearly served to reduce recording errors as revealed by internal cross-checks on the data form itself. The illogical, and hence detectable, error rate was less than 2%. The rate of replacement for replaceable missing teeth was highest in the upper age groups. Interestingly, data from a national population survey also shows the highest percentage of adult individuals needing fixed partial dentures, partial removable dentures, or both, in groups below 65 years of age whereas the percentage was lower for those above 65 years of age.6 The differences in replacement rates between age groups in the present study was almost exclusively a result of differences between replacement rates for molars and premolars, inasmuch as the rates for canines and incisors were high in all age groups. The figures indicate that there may be an unmet need for the replacement of molars and premolars, depending on the philosophy guiding the treatment as to what extent all missing teeth should be replaced. This notion is in accordance with the conclusion recently made that there is a substantial unmet need for fixed and removable dentures.’ Compared with corresponding figures from studies of patient groups from the Scandinavian countries’,’ the U.S. figures tend to show higher replacement rates for premolars and molars for regular dental care users. Differences in the willingness to tolerate open premolar and molar spaces, economic factors, or differences in professional standards are possible reasons that may explain the cross-cultural differences in replacement rates. The relative proportion of the different replacements shows that the fixed partial prostheses contributed 378
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KATZ
only a small share to the total replacements in the present study. Although the ratio of the number of teeth replaced by removable:fixed prostheses is 19:1 for 60 to 69-year-olds, care should be taken not to misinterpret this ratio as representing a ratio of patients with fixed or removable prostheses. This 19:l ratio, based on the 60 to 69-year-old age group data from Table III, refers only to replaced missing teeth. Quite clearly, the choice to use a removable prosthesis is influenced by many factors (financial as well as intraoral factors) and will tend to be used for patients requiring the replacement of many teeth in one arch. Thus, the ratio of patients with removable:fixed prostheses would be considerably less than 19:l. Comparison with Norwegian data9 from 35to 45-year-old dental patients indicates a similar removable:fixed prosthesis ratio (approximately 3:l) in the corresponding U.S. age groups. It should be noted that although the percentage of fixed partial denture replacements in the youngest age group is relatively high, the absolute number of replacements in this age group is low. The finding that the youngest and oldest age groups showed the highest use of acid-etched fixed partial dentures (20% and 13% of fixed partial denture use) may indicate future trends for the special intraoral conditions exhibited by these two age groups. It may also be seen as an early indication of an increasing overall use of acid-etched cast fixed partial dentures, given that this technique was virtually unknown a decade ago. SUMMARY This report describes the pattern of tooth replacement for a random sample of adult dental patients in a major urban area in the northeastern United States. The data were collected by using a practitioner-based epidemiologic monitoring system that had been established with the local dental society. Nearly 90% of the randomly selected dentists collected the data on all adult patients seen during a l-week period. The 2069 patients examined were predominantly regular users of dental care with a relatively even distribution across lo-year age groups. There was a slight preponderance of women in the sample (55%). There were no significant differences between men and women in terms of mean numbers of missing teeth. Overall, 92% were dentulous in both arches, 6% were edentulous in one arch, and 2% were totally edentulous. When the space was available for replacement, molars and premolars showed the lowest percentages of replacement in both arches for each age group. Overall, 14.4% of the replaced teeth were replaced by a fixed partial denture, of which acid-etched fixed partial dentures contributed 0.6% and conventional fixed partial dentures the remaining 13.8%. Removable prostheses replaced 85.6% of the missing teeth. The proportion of fixed replacements was highest in the MARCH
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caries in New Zealand. J Dent Res 1961(Special issue):1327,
youngest age groups and the proportion of removable replacements was dominating in the older age groups. Acid-etched fixed partial dentures were found most frequently in the youngest and oldest age groups.
1982. American Dental Association, The Bureau of Economic and Behavioral Research. The 1984 Survey of Dental Practice: Patient Visits to the Dentist. Chicago, 1984, ADA. Institute of Medicine: Division of Health Care Services Public Policy Options for Better Dental Health: Report of a Study, IOM Pub. No. 80-86. Washington, D.C., 1980, National Academy Press. Douglass CW: The role of specialists and general practitioners in provision of prosthetic services. J PROSTHET DENT 40~844, 1984. Bjorn AL, Oval1 B: Partial edentulism and its prosthetic treatment. A frequency study within a Swedish population. Swed Dent J 3:15, 1979. Gustavsen F, Silness J: Tooth loss and tooth replacement among regular dental care users. J Dent Res 1962(Special issue):249, 1983 (Abstr. No. 720).
This is the second in a series of reports on this practicing dentist-based epidemiologic monitoring system on adult oral health referred to as the Slice-of-Life Project. The initial and sustained support of the leadership and membership of the Hartford Dental Society is acknowledged by the authors as critical to the quality of this collaborative research project.
REFERENCES 1. Brunelle JA, Carlos JP: Changes in the prevalence of dental caries in U.S. school children, 1961-1980. J Dent Res 1961(Special issue):1346, 1982. 2. Von der Fehr FR: Evidence of decreasing caries prevalence in Norway. J Dent Res 1961(Special issue):1331, 1982. 3. Koch G: Evidence for declining caries prevalence in Sweden. J Dent Res 1961(Specialissue):1340,1982. 4. Brown RH: Evidence of decrease in the prevalence of dental
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DR. FINN GUSTAVSEN UNIVERSITYOF CONNECTICUTHEALTH CENTER SCHOLLOF DENTAL MEDICINE FARMINGTON,CT 06032-9984
Correction In the article “The effects of surface texture and grooving on the retention of cast crowns” (J PROSTHET DENT 1986;56:421-4), an error occurred in the last line of the Conclusions. It should
read: In contrast, there were no statistically significant differences in crown retention for zinc phosphate cement between grooved crowns with smooth and rough finish tooth surfaces and plain crowns with a smooth finish tooth surface. The only combination that is contraindicated for zinc phosphate cement is the plain crown with a rough surface finish. The authors regret the error.
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