HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by HEFT, M. W. Articles by FOERSTER, U. Search for Related Content PubMed PubMed Citation Articles by HEFT, M. W. Articles by FOERSTER, U.

JADA Continuing Education

24-MONTH INCIDENCE

	ABSTRACT

TOP ABSTRACT SUBJECTS AND METHODS STATISTICAL METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 
Background. There are few reports in the literature regarding estimates of the occurrence of tooth fractures. Most studies have assessed tooth fractures in people seeking dental care, which may underestimate the incidence of the problem.

Methods. This study sought to estimate the incidence and prevalence of cusp and restoration fractures, as well as root fragments in participants in the Florida Dental Care Study, a diverse representative sample of community-dwelling residents of four north Florida counties made up of people who seek dental care regularly and those who do not. Participants received a dental examination and an in-person interview at baseline and at a 24-month follow-up session.

Results. At least 20 percent of the participants were diagnosed as having bulk restoration fractures, cusp fractures or root fragments at the baseline visit. At the 24-month follow-up session, 26 percent of the participants had at least one new occurrence of these problems. Of those subjects presenting with tooth fracture, 25 percent had multiple teeth affected. African-Americans and people who sought care on a problem-oriented basis experienced twice the rate of cusp fracture and a higher rate of root fragments as did those who sought care on a regular basis. These data represent consecutive prevalence estimates rather than the true incidence, in that fractures that occurred after baseline may have been treated in the intervening 24 months. Thus, these data represent "lower-bound" incidence estimates.

Conclusions. These results suggest that restoration fractures, cusp fractures and root fragments are a significant dental health problem, and that selected segments of the population are at greater risk of developing these problems.

Clinical Implications. These data are useful for dentists in understanding the magnitude of the problem and the potential progression of fractures and root fragments.

Clinical judgment of the potential for tooth fracture, restoration fracture or both is an important factor when evaluating tooth status for dental restorative treatment planning decisions.^1–6 This judgment involves the clinician’s assessment of the likelihood that the tooth will remain intact and can withstand normal use. For example, a prosthetic crown may be placed in anticipation of a crown fracture, rather than solely to replace missing functional tooth structure.

There are few reports in the literature that provide estimates of the occurrence of tooth fractures. Moreover, these studies usually consider tooth fractures as an umbrella category that includes the full range of potential cusp, tooth and restoration fractures. One recent study reported the occurrence of complete tooth fracture to be 5.0 teeth per 100 adults per year.⁷ Complete tooth fractures in that study referred to a "cusp or piece of tooth completely broken away." Because that study⁷ and most studies have focused on limited patient samples—that is, people who have actually sought dental care—they provide limited insight into the magnitude of the problem in the general population. Studies of patient populations may overestimate the occurrence of problems that warrant clinical intervention,⁷ but underestimate the magnitude of all untreated conditions. An additional important issue that cannot be addressed from prevalence data is the potential progression of, or sequelae from, unrestored fractures of teeth or restorations.

The significance of tooth fracture has profound implications for oral health and functioning and may affect a person’s decision to seek dental care. For example, tooth fracture that immediately leads to tooth pain most likely would lead a patient to seek dental care. Tooth fracture also may affect one’s ability to effectively masticate, either because of the direct impact of loss of tooth structure or because of pain on chewing. In addition, tooth fracture may be an esthetic concern that limits social interactions.⁸

To gain a greater understanding of the magnitude of the problem, we report on the occurrence of complete fractures in a community-dwelling sample made up of people who seek routine or problem-oriented dental care, as well as those who do not use any dental services. Specifically, we report on the prevalence and 24-month incidence of bulk restoration fractures, cusp fractures and root fragments, and whether these conditions are significant antecedents for either tooth extraction or crown placement. These data provide some insight into the likely progression of these problems.

	SUBJECTS AND METHODS

TOP ABSTRACT SUBJECTS AND METHODS STATISTICAL METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 
Data for this study were derived from the Florida Dental Care Study, or FDCS, a prospective longitudinal cohort study of oral health and dental care. A detailed description of the study and sampling methods has been published elsewhere.⁹ The study sample was representative of the communities of interest in four north Florida counties.⁹ Because an important outcome of interest for the overall study was tooth loss,¹⁰ an additional condition for enrollment in the study was that participants had to have at least one remaining tooth. Baseline data collection for this study began in 1993 with 873 participants, and 723 subjects participated in the 24-month follow-up sessions.

The 873 subjects who were enrolled at baseline resulted in a sample of only modest bias with respect to the population of interest, as detailed elsewhere.⁹ The recency of dental care for this sample at baseline was similar to that in recent U.S. National Health Interview Survey, or NHIS, data, and conclusions drawn from the FDCS and the NHIS regarding sociodemographic determinants of dental care recency were the same.⁹ In addition, the percent-age of subjects in the sample who had one or more dental visits in the first two years of the FDCS was similar to the percentage of subjects in the comparable group of NHIS respondents (that is, 77 percent vs. 75 percent, respectively).^11,12

At the 24-month follow-up, 187 subjects had developed at least one new occurrence of fracture or root fragment.

Interviews and dental examinations. The baseline and 24-month follow-up visits included an in-person interview and a clinical dental examination. At the clinical dental examination, researchers from the FDCS recorded the presence and location of remaining teeth, dental caries, root fragments, bulk restoration fractures, fractured teeth (complete incisal edge fractures, dental cusp fractures or both will be referred to as cusp fractures), root defects and tooth mobility, as well as periodontal attachment levels. A diagnosis of bulk fracture for a given tooth was limited to amalgam restorations, composite restorations and temporary restorations. The tooth had to have a fractured restoration—including those that were partly or wholly missing—without caries at the area of fracture. A cusp or incisal-edge fracture was diagnosed if the fracture was more than 2 millimeters in occlusoapical or axial depth and there was no caries at the site of fracture; width was not a criterion. Therefore, a single tooth could receive a diagnosis of caries and restoration fracture, caries and cusp/incisal-edge fracture or both, but only if the fracture was not adjacent to the caries. Root fragments were defined as teeth that had more than three-fourths of the anatomic (not clinical) crown missing.

Dental examiners. Inter-examiner reliability for the outcomes of interest at baseline has been described elsewhere.¹⁰ Six dental examiners from the FDCS participated in standardization and calibration training sessions before the baseline field phase began, and five of the original six examiners were recalibrated before the follow-up examination at 24 months.

The in-person interview provided demographic information about participants; information about the presence of dental symptoms, oral symptoms or both; information about oral health behaviors; and information about oral health care attitudes. Exact questionnaire wording can be found at the FDCS Web site.¹³ Of importance to the present investigation were questions regarding subjects’ approach to dental care (that is, no attendance, problem-oriented attendance or regular attendance) and ability to pay an unexpected $500 dental bill (that is, able to pay comfortably, able to pay with difficulty or not able to pay the bill), because these factors have been shown to have significant impact on oral health status.⁸

	STATISTICAL METHODS

TOP ABSTRACT SUBJECTS AND METHODS STATISTICAL METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 
Segments of the study population were overrepresented in the sample to ensure adequate numbers for analyses. However, we weighted results in the analyses to reflect the true population in the counties studied.⁹ All analyses were done in the Statistical Analysis System, or SAS, environment.¹⁴ We used the ² test for bivariate comparisons when the variables were categorical. We conducted logistic regression analyses using the LOGISTIC procedure in SAS.¹³

	RESULTS

TOP ABSTRACT SUBJECTS AND METHODS STATISTICAL METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 
Table 1 shows the prevalences of bulk restoration fractures, cusp/incisal-edge fractures and root fragments among the 723 subjects who were examined at both the baseline and 24-month follow-up visits. By comparison, the prevalences of these outcomes of interest at baseline for the original 873 enrollees were as follows: 15.5 percent for bulk restoration fractures, 13.7 percent for cusp/incisal fractures and 10.3 percent for root fragments. As shown in Table 1, these baseline rates were similar to those for the 723 subjects who were still enrolled at 24 months, and suggest that there was little, if any, attrition bias in the FDCS sample at follow-up. At least 20 percent of the participants were affected by at least one of these conditions at either of the two sessions.

View this table: [in this window] [in a new window]   TABLE 1 CONSECUTIVE PREVALENCE OF RESTORATION FRACTURES, CUSP FRACTURES AND ROOT FRAGMENTS AT BASELINE AND 24 MONTHS.*

 
Table 2 shows the 24-month incidence of bulk restoration and cusp fractures, root fragments and crown restorations. One hundred eighty-seven subjects (26 percent) had developed at least one new occurrence of fracture or root fragment. At least 25 percent of those affected had multiple teeth involved.

View this table: [in this window] [in a new window]   TABLE 2 OCCURRENCES OF RESTORATION FRACTURES, CUSP FRACTURES, ROOT FRAGMENTS AND CROWNS AT 24 MONTHS.*

 
We provide incidence data for new crown restorations in the FDCS because crowns are commonly placed to restore lost tooth structure for a fractured tooth or placed preemptively on teeth that are more likely to be fractured (for example, after endodontic treatment). More than 15 percent of participants received new crown restorations in the 24 months after the baseline examinations. Approximately 40 percent of these people received more than one crown.

Table 3 shows the consecutive prevalence data at baseline and at 24 months. We refer to the 24-month findings as "consecutive prevalence" rather than incidence because it is likely that some fractures that occurred since baseline were treated or the teeth had been extracted; consequently, these events would not have been recorded at the 24-month examination. While the prevalence levels were similar at the two sessions, the 24-month prevalence data include both new fractures and crowns as well as fractures and crowns seen at baseline. Thus, a significant portion of the previously identified affected teeth had been treated between the baseline and 24-month examinations. The incidence rates were as follows: 13 teeth with bulk fractures per 100 people, 14 teeth with cusp fractures per 100 people and 11 root fragments per 100 people. Furthermore, although 227 new crowns were placed, this reflected an increase of only 89 in the number of crowned teeth. Thus, 138 previously crowned teeth had been extracted between baseline and 24 months.

View this table: [in this window] [in a new window]   TABLE 3 CONSECUTIVE PREVALENCE OF RESTORATION FRACTURES, CUSP FRACTURES, ROOT FRAGMENTS AND CROWNS AT BASELINE AND 24 MONTHS.*

 
Rates of new occurrences of cusp fractures and root fragments at 24 months were higher for subjects who sought dental care on a problem-oriented basis (or who did not seek care) than for subjects who received care on a regular basis (or occasionally, but not only for dental problems) (19.7 percent vs. 9.8 percent, respectively, for cusp fractures and 25.2 percent vs. 3.0 percent, respectively, for root fragments) as well as for African-Americans than for whites (23.6 percent vs. 10.8 percent, respectively, for cusp fractures and 21.2 percent vs. 9.5 percent, respectively, for root fragments). Furthermore, rates of new occurrences of cusp fractures and root fragments were higher among subjects who reported that they could not pay an unexpected $500 dental bill than among those who reported they could pay, with difficulty, and among those who reported they could pay comfortably (24.7 percent vs. 17.1 percent vs. 8.9 percent for cusp fractures, respectively, and 29.4 percent vs. 17.5 percent vs. 4.2 percent for root fragments, respectively).

Three logistic multiple regressions identified independent determinants of restoration fractures, cusp fractures and root fragments. Four explanatory covariates were included in each regression equation:

– approach to dental care;

– race;

– ability to pay an unexpected $500 dental bill;

– number of teeth present at baseline.

For the sake of brevity, we present only the key conclusions here. None of the four covariates was statistically significant in the logistic regression equation in which new bulk fractures was the outcome of interest. In the second regression equation, approach to dental care was significantly associated with new cusp fractures (P = . 05). In the third regression equation, approach to dental care (P < .001) and ability to pay an unexpected $500 dental bill (P < .05) were significantly associated with root fragments, even when race was taken into consideration. Thus, people who do not seek care or seek only problem-oriented care are more likely to have untreated cusp fractures, and people who seek dental care on an irregular basis or are less able to pay an unexpected $500 dental bill are more likely to have untreated root fragments.

The 24-month status of the teeth that were affected at baseline is shown in Table 4. About 20 percent of the teeth with bulk restoration fractures at baseline had cusp fractures or root fragments at the 24-month examination. Similarly, approximately 4 percent of teeth with cusp fractures at baseline had root fragments at 24 months. Finally, 10.1 percent of new crowns at 24 months were placed on teeth that had been identified at baseline as having bulk restoration or cusp fractures.

View this table: [in this window] [in a new window]   TABLE 4 STATUS OF TEETH WITH BASELINE FRACTURES OR ROOT FRAGMENTS AT 24 MONTHS.

 

	DISCUSSION

TOP ABSTRACT SUBJECTS AND METHODS STATISTICAL METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 
The results of this study provide evidence that cusp and restoration fractures and root fragments are a significant dental health problem. Bader and colleagues⁷ reported a per-year incidence rate for complete fractures of 5.0 teeth per 100 patients. Their reported incidence rate includes all complete tooth fractures of varying degree. By comparison, the fracture rates were higher in the FDCS, in which we classified fractures in two categories: bulk restoration fracture and cusp fracture. We also included root fragments as a third category because this outcome may have resulted from fracture, from dental caries or from both. One hundred eighty-seven participants (26 percent) had fractures or root fragments at 24 months, with the percentages roughly equally divided among those with bulk fractures (13 per 100 participants), cusp fractures (14 per 100 participants) and root fragments (11 per 100 participants). The one-year rates also would be significantly higher than those reported by Bader and colleagues.⁷

There are several possible explanations for the higher incidence rates we report in this study. First, while the FDCS is a community-based study whose study sample is representative of the communities of interest, all enrollees in the study were required to have at least one tooth (this was not a criterion of the study by Bader and colleagues⁷). Thus, by including only dentate subjects, the FDCS consists of a greater number of people at risk of developing tooth fracture, since edentulous people, by definition, are not at risk of developing tooth fracture. However, even if we adjust the rates of fracture and root fragments by assuming that the rate of edentulousness is 20 percent (thus reducing the at-risk rate among the study sample by one-fifth), our rates would still be higher than those reported by Bader and colleagues.⁷

A second important feature of the FDCS is that this community-based sample is composed of patients who do not seek care, those who seek only problem-oriented care and those who seek care on a regular basis. Previous investigations have assessed tooth fractures in practice-based settings involving patients who sought either regular or problem-oriented dental care. In our study, we demonstrated that people who do not seek dental care are twice as likely as others to have cusp fractures and approximately eight times as likely to have root fragments. Thus, practice-based studies probably are underestimating the magnitude of the problem.

A third important feature of this community-based study is that it recruited all types of patients and included a diverse sample. The inclusion of an in-person interview provided an opportunity to assess the association among demographic, behavioral and attitudinal factors as well as the occurrence of fractures and root fragments. Blacks were twice as likely as whites to experience cusp fractures and root fragments. The multivariate analyses addressed the relationships among race, approach to dental care, and ability to pay an unexpected $500 dental bill and the outcomes of interest. We found that people who seek problem-oriented care and those who are less able to pay an unexpected $500 dental bill are most likely to have untreated cusp fractures, and problem-oriented patients are most likely to have root fragments.

Finally, it is important to keep in mind that our rates for the occurrence of fractures and root fragments are not true incidence data, but rather are drawn from consecutive prevalence data. This is because participants may have experienced bulk restoration or cusp fracture or root fragments after the baseline session, and then underwent treatment before the 24-month follow-up session. Such occurrences would not have been recorded as an "event." Therefore, the consecutive prevalence approach most likely underestimates the magnitude of the problem.

	CONCLUSIONS

TOP ABSTRACT SUBJECTS AND METHODS STATISTICAL METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 
The results of this study suggest that about one in five dentate people will experience a bulk restoration fracture, cusp fracture or root fragment during a two-year period. Blacks and people who seek dental care on a problem-oriented basis are at greater risk of developing these problems. Further research should be directed toward understanding how behavioral and attitudinal factors, as well as clinical factors, may influence these outcomes.

	FOOTNOTES

Dr. Gilbert is a professor and chairman, Department of Diagnostic Sciences, University of Alabama at Birmingham.

Dr. Dolan is a professor, Department of Operative Dentistry, and associate dean for academic affairs, University of Florida, Gainesville.

Dr. Foerster is a clinical associate professor, Department of Operative Dentistry, University of Florida, Gainesville.

This investigation was supported by NIH grants DE-12587, DE-11020 and DE-00392. Additional support was provided by funds from the University of Florida.

The authors acknowledge the contributions of J.L. Earls and B.A. Ringelberg, who served as regional project coordinators for the Florida Dental Care Study through 24 months of data gathering.

The opinions and assertions contained herein are those of the authors and are not to be construed as necessarily representing the views of the University of Florida, the University of Alabama at Birmingham or the National Institutes of Health.

The informed consent of all subjects who participated in this investigation was obtained after the nature of the procedures had been explained fully.

	REFERENCES

TOP ABSTRACT SUBJECTS AND METHODS STATISTICAL METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 

1. Bader JD, Shugars DA, Roberson TM. Using crowns to prevent tooth fracture. Community Dent Oral Epidemiol 1996;24:47–51.[Medline]
   
   
2. Braly BV, Maxwell EH. Potential for tooth fracture in restorative dentistry. J Prosthet Dent 1981;45(4):411–4.[Medline]
   
   
3. Cavel WT, Kelsey WP, Blankenau RJ. An in vivo study of cuspal fracture. J Prosthet Dent 1985;53:38–42.[Medline]
   
   
4. Eakle WS, Maxwell EH, Braly BV. Fractures of posterior teeth in adults. JADA 1986;112:215–8.[Abstract]
   
   
5. Gher ME, Dunlap RM, Anderson MH, Kuhl LV. Clinical survey of fractured teeth. JADA 1987;114:174–7.[Abstract]
   
   
6. Lagouvardos P, Sourai P, Douvitsas G. Coronal fractures in posterior teeth. Oper Dent 1989;14:28–32.[Medline]
   
   
7. Bader JD, Martin JA, Shugars DA. Preliminary estimates of the incidence and consequences of tooth fracture. JADA 1995;126:1650–4.[Abstract/Free Full Text]
   
   
8. Gilbert GH, Duncan RP, Heft MW, Dolan TA, Vogel WB. Multidimensionality of oral health in dentate adults. Med Care 1998; 36:988–1001.[Medline]
   
   
9. Gilbert GH, Duncan RP, Kulley AM, Coward RT, Heft MW. Evaluation of bias and logistics in a survey of adults at increased risk for oral health decrements. J Public Health Dent 1997;57(1):48–58.[Medline]
   
   
10. Gilbert GH, Antonson DE, Mjör IA, et al. Coronal caries, root fragments, and restoration and cusp fractures in U.S. adults. Caries Res 1996;30:101–11.[Medline]
    
    
11. Bloom B, Gift HC, Jack SS. Dental services and oral health: United States, 1989. Vital Health Stat 10 1992;No. 183:31.
    
    
12. Gilbert GH, Duncan RP, Vogel WB. Determinants of dental care use in dentate adults: six-monthly use during a 24-month period in the Florida Dental Care Study. Soc Sci Med 1998;47(6):727–37.[Medline]
    
    
13. Florida Dental Care Study Web site. Available at: "nersp.nerdc.ufl.edu/~gilbert". Accessed Aug. 21, 2000.
    
    
14. SAS Institute Inc. SAS/STAT user’s guide, version 6. 4th ed. Cary, N.C.: SAS Institute Inc.; 1989.
    
    

This article has been cited by other articles:

				G. H. Gilbert Racial and Socioeconomic Disparities in Health from Population-Based Research to Practice-Based Research: The Example of Oral Health J Dent Educ., September 1, 2005; 69(9): 1003 - 1014. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by HEFT, M. W. Articles by FOERSTER, U. Search for Related Content PubMed PubMed Citation Articles by HEFT, M. W. Articles by FOERSTER, U.