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A number of articles have addressed gender differences in the productivity of dentists, but little is known about differences in practice patterns for caries management. This study compared the use of a comprehensive range of specific diagnostic methods, preventive agents, and restorative decision making for caries management between male and female dentists who were members of The Dental Practice-Based Research Network(DPBRN).
This study surveyed general dentists who were members of DPBRN and who practiced within the United States. The survey asked about dentist, practice, and patient characteristics, as well as prevention, assessment, and treatment of dental caries. Differences in years since dental school graduation, practice model, full/part-time status, and practice owner/employee were adjusted in the statistical models, before making conclusions about gender differences.
Three hundred ninety-three male (84%) and seventy-three female (16%) dentists participated. Female dentists recommended at-home fluoride to a significantly larger proportion of their patients, whereas males had a preference for using in-office fluoride treatments with pediatric patients. Female dentists also choose to restore interproximal lesions at a significantly later stage of development, preferring to use preventive therapy more often at earlier stages of dental caries. There were few differences in diagnostic methods, time spent on or charges for restorative dentistry, and busyness of their practices.
DPBRN female dentists differ from their male counterparts in some aspects of the prevention, assessment, and treatment of dental caries, even with significant covariates taken into account. Practice patterns of female dentists suggest a greater caries preventive treatment philosophy.
As is true for other professions, an increasing number of women are entering the practice of dentistry. In 1990, women constituted approximately 12% of practicing dentists, and it has been projected for 2010 that women will account for 22% of all practicing dentists (1). Furthermore, the proportion of women graduates of dental schools in the United States (US) was up to 44% in 2008, suggesting there may be even greater proportions of female dentists in future years (2).
Many articles have addressed issues of productivity, with the subtle implication that male dentists provide more dental care, and therefore serve the needs of the community to a greater extent than female dentists. These studies report that women dentists have lower incomes, work less hours per week, see fewer patients, and are more likely to work part-time (3–11). Fewer studies have reported specifically on female dentists’ clinical decision patterns. A report about Australian dentists by Brennan found higher rates of caries prevention used by female dentists (12); however, Atchison (6) did not find gender differences in services that were grouped into a single category of “sealants/fluoride varnish/topical varnishes.” The Brennan study did not find gender differences for general categories of diagnostic or restorative treatment(12). These studies combined specific services into higher-order categories for each area of service provided, so inferences about preferences for one treatment or preventive method over another are not possible. Studies of female physicians show greater attention to the preventive aspects of patient care (13,14).
Scientific findings have supported a shift towards greater use of prevention and more-conservative management of caries by dental practitioners (15–19). Considering that on average, female dentists are younger and are more-recent graduates (5,12,20), we would expect to find that as a group they may be using more caries prevention and a more-conservative management approach to caries consistent with current recommendations. Understanding these practice patterns are particularly relevant as the treatment of dental caries is the most common procedure performed by general dentists (21).
To our knowledge, no study has compared the use of a comprehensive range of diagnostic methods, preventive agents, and restorative decision making for caries management between male and female dentists. We have such an opportunity with the data from the current study, in which we survey dentist practitioner-investigators in The Dental Practice-Based Research Network (DPBRN). The aim of this study was to test the hypothesis that, with key covariates already taken into account, female dentists 1) use caries prevention agents in a larger percentage of their patients, 2) prioritize caries risk factors differently, 3) practice caries risk assessment differently, 4)use different caries diagnostic techniques, and 5) make restorative decisions using restorative case scenarios that are more-conservative than male dentists.
The DPBRN is a consortium of participating practices and dental organizations committed to advancing knowledge of dental practice and finding ways to improve it. DPBRN mainly comprises dentist practitioner-investigators in five regions: Alabama/Mississippi; Florida/Georgia; dentists employed by HealthPartners and private practitioners in Minnesota; Permanente Dental Associates in cooperation with Kaiser Permanente Center for Health Research; and Denmark, Norway, and Sweden (22). Participants of DPBRN were recruited through continuing education courses and mass mailings to licensed dentists from the participating regions.
DPBRN has a wide representation of practice types, treatment philosophies, and patient populations, including diversity with regard to the race, ethnicity, geography and rural/urban area of residence of both its practitioner-investigators and their patients (23). The DPBRN dentists, while intended to draw on a diverse geographical area and practice types, are not a random sample. However, we have demonstrated that they have much in common with dentists at large, and in fact the only characteristic that was statistically different from American Dental Association survey data was the number of years since graduation from dental school (23).
The main objective of the use of the “DPBRN Enrollment Questionnaire” was to provide estimates of the frequency of key characteristics of DPBRN dentists with the goal to develop a pool of 200 dentists who would be appropriate for inclusion in subsequent studies envisioned for the DPBRN. To develop this pool of about 200 dentists, a target of at least 300 to complete the Enrollment Questionnaire was set. Ultimately, that number was exceeded by having more than 500.
As part of enrollment in DPBRN, all practitioner-investigators completed an Enrollment Questionnaire about their practice characteristics and themselves. An “Assessment of Caries Diagnosis and Caries Treatment” questionnaire was sent to DPBRN dentists who reported in the Enrollment Questionnaire doing at least some restorative dentistry. A pilot study documented comprehension and item test-retest reliability across 15 days using a sample of 35 network dentists. All items in the final version met a test-retest reliability cutoff of kappa > 0.7. These questionnaires are available at http://www.dpbrn.org/users/publications/Supplement.aspx. Practitioner-investigators were asked to return the questionnaire within three weeks, with a second reminder sent after an additional three weeks.
The following selected questions queried use of preventive agents: For adults; of patients more than 18 years old with at least one posterior tooth, for what percentage do you: Apply dental sealants on the occlusal surfaces of at least one tooth? Administer an in-office fluoride application, such as fluoride gel, fluoride varnish, or fluoride rinse? Recommend a non-prescription (over-the-counter) fluoride rinse? Provide a prescription for some form of fluoride? Recommend an at-home regimen of Chlorhexidine rinse? For children; of patients 6 to 18 years old for what percentage do you: Apply dental sealants on the occlusal surface of at least one of their permanent teeth? Administer an in-office fluoride application, such as fluoride gel, fluoride varnish, or fluoride rinse? Recommend a non-prescription (over-the-counter) fluoride rinse? Provide a prescription for some form of fluoride?
Items asked about the importance of caries risk factors and the use of caries risk assessment and are presented in Table 1 and Table 2 respectively. Questions administered about the frequency of caries-related diagnostic methods are listed in Table 3.
Dentists were asked to select the treatment codes they would recommend for each of a set of five radiographs of interproximnal and occlusal lesions that varied on lesion severity/depth (Figure 1). Each set of radiographs also had accompanying clinical scenarios that described patients of low and high caries risk. The interproximal series also had a pediatric case scenario. The scenarios are described in Figure 1. Treatment codes categorized as conservative/preventive were: no treatment today, follow the patient regularly; instruct the patient in plaque removal for the affected area; in-office fluoride; prescription fluoride; recommend non-prescription fluoride; use sealant or unfilled resin over the tooth; chlorhexidine treatment. Codes categorized as repair/replace were: polish, resurface, or repair restoration but not replace; replace entire restoration. When multiple codes were selected, the treatment was scored as “repair/replace” if either of the repair or replace restoration codes were endorsed. Each of the clinical scenarios were initially scored based on the least severity/depth (see Figure 1)at which the dentist would first select to restore the lesion rather than perform only preventive therapy. Because of small cell sizes, E1/E2 and D2/D3 were collapsed and the level for restoration was recoded as E1/E2=1, D1=2, and D2/D3=3.
These five scores(occlusal/low-risk scenario; occlusal/higher-risk scenario; pediatric occlusal; interproximal/low-risk; interproximal/higher-risk) reflect a treatment continuum based in lesion severity/depth, and were used to create a variable we refer to as the “restoration index” for each of the five scenarios. A higher restoration index means that the dentist intervenes surgically on lesions of greater depth, and is consistent with a more-conservative caries treatment philosophy for each case.
The “years since dental school graduation” variable was created by subtracting the reported year of graduation from the year the survey was completed. Practices were characterized by “type of practice” for each dentist as being in either: (1) a solo or small group private practice (SPP); (2) a large group practice (LGP); or (3) a public health practice (PHP). “Small” practices were defined as those that had 3 or fewer dentists. Public health practices were defined as those that receive the majority of their funding from public sources.
The general linear model (GLM) was used to test for dentist gender differences in the percentages of patients receiving each caries treatment(hypothesis 1). Logistic regression was used to test for differences in the priority given to each of the caries risk factors (hypothesis 2) once the rating of importance was dichotomized to allow comparisons between very or extremely important with less important categories (not at all, slightly or moderately important). Differences in caries risk assessment and individualized caries prevention (hypothesis 3) were tested using GLM for parametric models and logistic regression for dichotomous responses. GLM was also used to test for differences in the frequency of use of specific diagnostic methods for caries(hypothesis 4). Differences in the restoration index as a function of patient risk and lesion site were tested using generalized estimating equations to adjust for multiple responses from each dentist(hypothesis 5).
Males were coded=0 and females=1. Years since graduation, practice type (LGP/PHP=0, SPP=1), part-time practice (32+hours=0, less than 32 hours=1), and practice ownership (not owner/partner=0, owner/partner=1) were adjusted in all statistical models to ameliorate bias related to different training experiences or practice situations that may account for gender differences in practice patterns. The presence of two-way interactions between gender and both years since graduation and practice type were also tested and where significant, separate models by gender were used to interpret the interaction effects.
A “DPBRN region” variable was also created, but multicollinearity with the practice type variable precluded using both in the same regression model. Statistical models were tested substituting the region variable for the practice type variable with no substantive differences in the results. All tables and figures show adjusted means. Analysis was performed using SPSS 16.0 (24).
A total of 932 DPBRN dentist practitioner-investigators were eligible, of whom 534 responded, for an overall return rate of 58 percent. There were no participation differences by gender or years since dental school graduation. This study reports on the 466 practitioner-investigators who reported performing non-implant restorative treatment, practiced within the United States, and were general dentists. Dentists from the Scandinavian region were excluded because of potential differences in practice patterns associated with greater prevention orientation of these countries (25). Dentist, patient, and practice characteristics are presented in Table 5. There were no gender differences in the race/ethnicity of the dentists. Female dentists were more-recent graduates from dental school (p < .001), and were more likely to be working part-time (p = .002). However, when only full-time dentists were considered, there were no differences in the number of patients seen each week by male or female dentists. Male and female dentists were distributed equally across the three practice models, but female dentists were less likely to be a practice owner or partner (p < .001). There were no gender differences in the number of days a patient waited for an examination appointment or treatment appointment. Male and female dentists treated an equal proportion of pediatric and geriatric patients. There were no differences in the percentage of time spent on restorative treatment, the fees charged for a 2-surface amalgam, or the percentage of patients with dental insurance.
Figure 2 presents the percentages of pediatric patients who received various preventive agents by network dentists(hypothesis 1). Female dentists were significantly more likely to have recommended an at-home regimen of non-prescription fluoride (adjusted means; male, 30%, female, 36%; β = 5.932, p = .041) on pediatric patients than male dentists. Male dentists were significantly more likely to have applied an in-office fluoride (male, 86%, female, 78%; β = −7.673, p = .015) than female dentists. In addition, a significant gender × graduation year interaction resulted, in that a negative association between years since graduation and the frequency of the use of in-office fluoride on pediatric patients was only significant for female dentists (β=1.156, p = .013). There were no gender differences for recommending a prescription fluoride regimen or having applied a dental sealant. Readers are reminded that in this context, the interpretation of a beta would be the change in the dependent variable (percentage) comparing male to female dentists when adjusting for covariates.
Figure 2 presents the use of preventive agents on adult patients by network dentists (hypothesis 1). Female dentists were significantly more likely to have recommended an at-home regimen of either non-prescription (adjusted means; male, 25%, female, 34%; β = 6.567, p = .029) or prescription fluoride treatment (male, 21%, female, 33%; β = 7.650, p = .005) for adult patients than male dentists. A significant gender × graduation year effect was found, in that a negative association between years since graduation and the frequency of the use of in-office fluoride on adult patients was only significant for female dentists (β = −1.103, p = .041). There were no differences for the use of a dental sealant, in-office fluoride, or chlorhexidine rinse.
Table 1 presents the odds ratios from logistic regression analysis testing for gender differences in the importance of risk factors for use in treatment planning(hypothesis 2). For pediatric patients, female dentists rated recent caries (OR = 1.8, p= .012), presence of several large restorations (OR = 2.3, p= .006), and the current use of fluorides (OR = 1.5, p = .049) as very or extremely important factors to consider in a treatment plan than male dentists. For adult patients, female dentists rated one or more active caries (OR = 2.1, p= .018), recent caries (OR = 1.6, p= .001), current use of fluorides (OR = 1.4, p = .034), and recession or root exposure (OR = 2.9, p < .001) as very or extremely important factors to consider in a treatment plan than male dentists. Ratings of importance for patient’s age, decreased salivary flow, current oral hygiene, current diet, the dentist’s subjective assessment, or the patient’s socioeconomic status were not different for both pediatric and adult patients.
Table 2 presents the practice of caries risk assessment and individualized caries prevention treatment by dentist’s gender(hypothesis 3). There were no differences in caries risk assessment, but females reported that their patients were more interested in individualized caries prevention (β = 8.212, p = .035)and more likely to receive individualized caries prevention (β = 14.816, p < .001) than patients of male dentists. There was not a gender difference in agreement that the use of caries risk assessment is predictive of whether or not patients will develop caries in the future.
Table 3 presents the use of diagnostic methods commonly used for assessment of caries. The only significant gender difference in caries diagnostic methods was that male dentists reported a greater frequency of use of magnification to diagnose a carious lesion (63%) of their patients compared to females (48%).
Table 5 shows the significant predictors for each dentist’s restoration index (threshold for performing a restoration)for each clinical scenario. Female dentists were significantly more conservative (e.g., restore at greater lesion depth) than male dentists on the interproximal lesion (p = 0.031) scenarios. There were no gender differences on the occlusal scenarios.
To our knowledge, this is the first study to examine the use of a comprehensive range of diagnostic methods, preventive agents, and restorative decisions for caries between male and female dentists. Overall, among general dentists who were members of The Dental Practice-Based Research Network and practicing in the US, female dentists had a greater orientation for caries prevention and made more-conservative clinical decision in caries treatment in some situations than male dentists. However, there were as many areas of practice where they are similar as different.
It has been shown that male and female dentists both performed similar numbers of procedures per patient and received similar income per patient seen in practice (4). In further support of this conclusion, this study shows that when only full-time dentists were considered, males and females had equal amounts of patients. Although total income was not asked, these data also showed that fees charged by female dentists for restorations were similar to their male counterparts, and female dentists were equally likely to see patients with dental insurance. If differences in income per patient do exist, they could relate to the types of procedures performed, as one previous study has found that female dentists refer complex and potentially more-profitable cases to specialists more often than male dentists (6).
Although the dental literature is mixed (6,12), female dentists had a greater overall preventive orientation than male dentists for both adult and pediatric patients. Consistent with increases in the proportion of females graduating from US dental schools, female DPBRN dentists were younger and more-recent graduates than their male colleagues. These graduation patterns coincide with findings from other DPBRN studies that show dentists with fewer years since graduation were more likely to have recommended preventive treatment than those with more years since graduation (26). Brennan and Spencer found that for both genders, dentists aged 29 years and younger had higher preventive treatment rates than those over 65 years of age (12). Adjustments for gender-related differences in the graduation year and related interactions were made in the statistical analysis. The only finding contrary to the hypothesis for greater prevention among female dentists was that males tend to use in-office fluoride more often on pediatric patients.
There are many elements that can affect rate of preventive services in dental offices which could be associated with gender (27). For example, residing in a lower socioeconomic status location was associated with a lower preventive rate among Australian dentists (12). Another study found that 62% of the dental respondents indicated that the patient’s behavior influenced decisions to place a sealant (28). Other important factors could include whether the patient has dental insurance, local norms for prevention, caries risk of the dentist’s patient pool, or even that patients with a high priority for caries prevention also seek out a female dentist (29). One study has linked reimbursement rates and the use of in-office administered fluorides by dentists (28) and another found that increased financial incentive significantly increased sealant use on the molars of children, whereas education in evidenced-based practice did not (30). Neither of these studies tested for gender effects. There were no gender differences in the percent of patients seen in a practice who have dental insurance in this sample, suggesting minimal gender bias associated with financial incentives.
Caries risk assessment has been examined in several recent studies. Caries risk assessment determines the probability of caries incidence in a certain period of time (29), and this study suggests that female dentists consider caries history as more important in treatment planning than male dentists. There were few differences in diagnostic methods employed by male and female dentists, and both agreed on the effectiveness of caries risk assessment. However, our previous report has indicated that while gender was not associated with the practice of risk assessment, it did show considerable variability in how risk was determined (31). There were few gender differences in diagnostic methods. Although not differing by gender, 90% of network dentists reported that they use an explorer to probe the margin of an existing restoration, a procedure thought to be inadequate for caries detection and with potential for iatrogenic injury (32).
Female dentists took a more-conservative approach to restoration on the case scenario that involved patients with interproximal lesions. However, it was fewer years since graduation, and not gender, that was associated with restoration at a greater lesion depth (more-conservative approach) for the occlusal lesion scenarios. One reason for avoiding early restorations is that it reduces the probability of multiple replacements, which in turn further weakens the tooth structure (33). However, as stated previously, another study found no difference between male and female dentists with regard to the number of procedures performed per patient (4).
Some limitations to these data should be noted. The study sample is not a random sample of general dentists in the United States. However, based on comparisons to dentists who responded to the 2004 ADA Survey of Dental Practice, DPBRN dentists have much in common with dentists at large (23). DPBRN dentists represent a substantial diversity with regard to practice settings, patient populations, rural-urban area of residence, and geographic locations. Participation rate was lowest in the AL/MS region and the majority of dentists recruited in that region were enrolled in DPBRN to participate in other studies before DPBRN became a network that comprises five regions, and this may explain their lower participation rate. The questions about preventive treatments were asked separately; consequently, we are unable to infer to what extent individual patients were given or had recommended single or multiple treatments. It should be noted that the gender tests on the importance of caries risk were comparing a binary coded variable moderately or less important with very or extremely important and that we do not imply that dentists differed on whether caries risk in a treatment plan is of general importance.
The hypotheses that female dentists would differ from male dentists on caries diagnosis and treatment were only partially supported. We found that female dentists who were members of The Dental Practice-Based Research Network have a greater preference than male dentists for individualized caries preventive regimens and are more likely to recommend at-home fluoride treatments for both pediatric and adult patients. Female dentists also took a more-conservative approach, choosing to restore interproximal lesions at a later stage of their development, while preferring to use preventive therapy at earlier stages. The data indicated that there were few gender differences in diagnostic methods, time spent doing restorative dentistry, and busyness of their practices. It appears that female dentists differ from their male counterparts in only some aspects of the prevention, treatment, and assessment of dental caries (25,33).
This investigation was supported by National Institutes of Health, National Institute of Dental and Craniofacial Research grants U01-DE-16746 and U01-DE-16747. An Internet site devoted to details about DPBRN is located at www.DPBRN.org. Opinions and assertions contained herein are those of the authors and are not to be construed as necessarily representing the views of the respective organizations or the National Institutes of Health. The informed consent of all human subjects who participated in this investigation was obtained after the nature of the procedures had been explained fully.
The DPBRN Collaborative Group comprises practitioner-investigators, faculty investigators, and staff members who contributed to this DPBRN activity. A list of these persons is at http://www.dpbrn.org/users/publications/Default.aspx
Joseph L. Riley, III, Department of Community Dentistry and Behavioral Science, College of Dentistry, University of Florida, Gainesville, Florida, USA.
Valeria V. Gordan, Department of Operative Dentistry, College of Dentistry, University of Florida, Gainesville, Florida, USA.
Kathleen M. Rouisse, Department of Community Dentistry and Behavioral Science, College of Dentistry, University of Florida, Gainesville, Florida, USA.
Jocelyn McClelland, Private practitioner in Alabaster, Alabama, USA.
Gregg H. Gilbert, Department of General Dental Sciences, School of Dentistry, University of Alabama at Birmingham, Birmingham, Alabama, USA.