Abstract
This study evaluated second-, third-, and fourth-year dental students’ ability to identify systemic conditions associated with periodontal disease, risk factors most important for referral, and medications with an effect on the periodontium and their ability to apply this knowledge to make clinical decisions regarding treatment and referral of periodontal patients. A twenty-one question survey was administered at one U.S. dental school in the spring semester of 2012 to elicit the students’ knowledge and confidence regarding clinical reasoning. The response rate was 86 percent. Periodontal risk factors were accurately selected by at least 50 percent of students in all three classes; these were poorly controlled diabetes, ≥6 mm pockets posteriorly, and lack of response to previous non-surgical therapy. Confidence in knowledge, knowledge of risk factors, and knowledge of medications with an effect on the periodontium improved with training and were predictive of better referral decision making. The greatest impact of training was seen on the students’ ability to make correct decisions about referral and treatment for seven clinical scenarios. Although the study found a large increase in the students’ abilities from the second through fourth years, the mean of 4.6 (out of 7) for the fourth-year students shows that, on average, those students missed correct treatment or referral on more than two of seven clinical cases. These results suggest that dental curricula should emphasize more critical decision making with respect to referral and treatment criteria in managing the periodontal patient.
- periodontics
- periodontal disease
- dental education
- clinical decisions
- diagnosis
- referral
- systemic disease
- risk factors
A recent epidemiologic study estimated that 47.2 percent or 64.7 million American adults have mild, moderate, or severe periodontitis.1 In adults aged sixty-five and older, 64 percent had either moderate or severe periodontitis.1 Although research and advancements in periodontal treatment are occurring at a rapid pace, periodontal disease remains one of the most prevalent non-communicable chronic diseases in our population and can result in tooth loss and contribute to the systemic inflammatory burden.2 Over the past decade, there has been increasing attention to the role periodontal disease plays in systemic diseases. While some studies have shown associations,3–13 to date there is no unequivocal evidence as to the exact nature of the relationship. Recently, the American Heart Association acknowledged that periodontal disease is associated with cardiovascular disease independent of known confounders.14
Irrespective of the nature of the relationship, current thinking provides a solid rationale for focusing on prevention, early intervention, and aggressive management of periodontal disease. For patients to receive appropriate care, general dentists not only need to be able to make accurate diagnoses, manage, and treat their patients with periodontal disease, but also to provide timely referral to a periodontist when necessary. However, one study showed that general dentists may be underdiagnosing periodontal disease, especially in its early stages.15 Additionally, research conducted by Dockter et al. and Cobb et al. indicates that general dentists may not be referring their patients early enough for successful periodontal intervention.16,17 Williams et al. surveyed dental and dental hygiene students, evaluating their attitudes about periodontal disease management, self-assessment regarding periodontal disease and referral, and knowledge of clinical findings that activate referral.18 They found that only 40 percent of the dental and 36 percent of the dental hygiene students reported confidence in diagnosing, treating, and appropriately referring patients with periodontal diseases. Those students were able to recognize critical disease and risk factors influencing referral with fairly good accuracy; however, clinical application of that knowledge indicated a gap between knowledge and applied clinical reasoning.
Patients at risk for periodontal diseases can often be overlooked during a routine dental examination because they appear to be in a state of periodontal health. However, there can be multiple combinations of risk factors, medications used, and systemic diseases that predispose patients to increased risk of periodontal issues in the future. There is a critical need to provide dental students and dental practitioners with guidelines to help them in the assessment and referral processes. A core component in the treatment, management, and referral of patients who present with periodontal disease is appropriate clinical decision making. One important goal of dental education is to provide students with the knowledge, attitudes, and critical thinking skills necessary to make sound clinical decisions. Given the current evidence regarding referral patterns and dental students’ difficulty in applying knowledge to appropriate clinical decisions,15,18 there is a need to assess what factors predict appropriate clinical decision making for dental students concerning treatment and referrals for their periodontal patients.
The aim of our study was to evaluate dental students’ ability to identify risk factors indicating the need for periodontal referral and to make clinical decisions regarding management and referral of patients with varying levels of periodontal disease with or without systemic conditions. The goal was to build on the previous study by Williams et al., who utilized a survey to evaluate dental and dental hygiene students’ knowledge, confidence, and clinical reasoning regarding referral to a periodontal specialist.18 Our expanded survey included medications with an influence on the periodontium and systemic conditions associated with periodontal disease. Likewise, we expanded the clinical cases from two to seven to provide a broader view of clinical decision making. Lastly, we evaluated the criteria used by dental students who were graduating (fourth-year students), entering their last year of clinic (third-year students), or entering their first year of clinic (second-year students) to assess the trajectory of knowledge acquisition and decision making ability during dental school.
Methods
This study was approved by the University of Missouri-Kansas City (UMKC) Adult Health Science Institutional Review Board (IRB Protocol #12-35X). A convenience sample of UMKC second-year, third-year, and fourth-year dental students was invited to complete the survey. All members of the second-year class (107 students), third-year class (102 students), and fourth-year class (ninety-eight students) were potential participants.
Students were recruited for participation during a lecture class in the spring semester of 2012. They were informed that their participation was entirely voluntary. To protect student anonymity, surveys were color-coded to allow identification of students by graduating class but contained no other identifying information. In each of the classes, the same person provided standardized instructions and administered the survey to ensure consistency.
Survey Development and Description
Portions of a survey previously developed and validated by Williams et al. were used.18 The twenty-one item questionnaire was divided into five domains. The first domain evaluated attitudes and self-assessment and consisted of six items measured on a five-point Likert scale from 1=strongly disagree to 5=strongly agree. The second domain, eliciting knowledge about critical factors important for referral, was assessed by having students identify the top four risk factors from a list of twelve deemed most important by a group of experts in the decision to refer to a periodontist. The third and fourth domains evaluated knowledge of the relationship between periodontal disease and systemic diseases and medications with an effect on the periodontium, respectively. This knowledge was elicited by identifying relevant items from a list containing some with an association and some unassociated items. The last domain utilized seven clinical scenarios developed to evaluate the students’ clinical decision making. Of these, six described patient cases clearly outside the general dentist’s scope of management, and one case was within the general dentist scope of practice.
Data Analysis
Questionnaire data were coded according to year of graduation and entered into SPSS (version 17.0). Simple descriptive statistics were computed to characterize respondents’ demographics, confidence in periodontal knowledge, beliefs about importance of periodontal disease, knowledge of risk factors most important to referring periodontal patients, and anticipated periodontal referral behavior after graduation. The percentage of students reporting anticipated plans to refer American Dental Association/American Academy of Periodontology (ADA/AAP) periodontal cases after graduation were reported descriptively. Similarly, the percentages who anticipated incorporating periodontal disease management into their practice after graduation were determined. Proportions were used to characterize students according to their ability to correctly identify periodontal disease risk factors critical to making appropriate periodontal referrals.
To examine the underlying factor structure of items assessing the domains of confidence, self-perception of risk factor knowledge, and beliefs about periodontal disease importance, principal components analysis with Varimax rotation was used. Based on item loadings, three subscales were identified and mean subscale scores computed for each (confidence in knowledge, belief of periodontal importance, and perceived knowledge of risk factors). Composite scores were also created by computing a mean score on the following four domains: correct identification of systemic conditions related to periodontal disease, incorrect identification of systemic conditions related to periodontal disease, knowledge of medications that influence the periodontium, and appropriate referral decisions on clinical cases.
Comparisons between training years were accomplished using both parametric (ANOVA) and non-parametric (Kruskal-Wallis) analyses. Finally, linear regression was used to empirically determine if students’ confidence in knowledge, belief of periodontal importance, knowledge of risk factors, knowledge about medications with an effect on the periodontium, and correct identification of systemic conditions were related to the number of correct referrals on cases.
Results
A total of 264 students (103 second-year, ninety-three third-year, and sixty-eight fourth-year students) completed the questionnaire, for an overall response rate of 86 percent. Of these, women comprised a majority of the second-year class (61.2 percent females) and the fourth-year class (66.2 percent females), with approximately equal numbers of males and females who responded in the third-year class (47.3 percent females). With respect to post-graduation planning, the majority of students planned to either join a group practice (44.1 percent second years, 33.7 percent third years, and 38.2 percent fourth years) or pursue advanced training (16.6 percent second years, 28.2 percent third years and 32.3 percent fourth years).
Principal components factor analysis with Varimax rotation was used to explore the underlying factor structure of items designed to elicit information on attitudes about periodontal disease management and confidence in training. Three factors were identified based on factor loadings ≥0.5: confidence in knowledge, belief of periodontal importance, and a single item risk factor referral. These three factors explained 50.3 percent of the variance in items, with a Kaiser-Meyer-Olkin Measure=0.75. Where items loaded negatively on the factor, items were reverse-scored and a mean subscale score computed for subsequent analyses. Internal consistency estimates of reliability were computed for each of the two composite subscales with α=0.71 and 0.62, respectively.
Members of the three classes were asked to predict their anticipated referral behavior for five ADA/AAP periodontal patient classifications (classes I through V) for patients with and without systemic conditions. The percentages of students who planned to refer in these four categories are shown in Table 1. Not surprisingly, the more experienced students reported that they anticipated referring the more difficult cases, with a clear trend differentiating between cases with and without systemic conditions. Second-year students, overall, were less likely to anticipate referring in all categories and did not differentiate between case type V with and without systemic conditions. When asked about their intention to do all periodontal surgery on their patient population, only a small percentage of students responded positively (see Table 2). However, a little less than a third of the students responded that they planned to do some periodontal surgery in their practice. Additionally, after graduation most students anticipated having the dental hygienist perform the maintenance on their patients.
Dental students’ plans to refer periodontal cases by case severity category with and without accompanying systemic conditions, by number and percentage of respondents by year
Dental students’ anticipated post-graduation scope of practice related to periodontal management, by percentage of respondents by year
To assess knowledge of referral risk factors, students were asked to identify the top four periodontal risk factors that they considered most critical to making a periodontal referral. Descriptive data on the proportion of students who selected each of the listed risk factors/clinical findings are shown in Table 3. Risk factors accurately selected by at least 48 percent of students in the three classes were poorly controlled diabetes, ≥6 mm pockets posteriorly, and unresponsiveness to previous non-surgical periodontal therapy. The proportion of students who identified anterior pockets as a clinical finding that might indicate the need for referral was lowest for the fourth-year-students. The proportion who selected age thirty-nine or younger as a risk factor increased only slightly as a function of advanced training, whereas the proportion of dental students who selected Class II furcation as a referral indication increased as a function of advanced training. Encouragingly, several of the “distracter” risk factors were selected by fewer than 20 percent of the respondents and included high plaque score, irregular dental attendance, and age forty years or older.
Dental students who correctly identified periodontal disease risk factors most critical to making a periodontal referral, by percentage of respondents for each year
The respondents’ attitudes and knowledge scales regarding referring periodontal patients are shown in Table 4. Comparing mean scores of attitudes and knowledge across the three training groups showed a clear and statistically significant trend towards more positive attitudes and greater knowledge as a function of increased training. Mean scores for confidence in knowledge, knowledge of risk factors, correct identification of systemic conditions, and knowledge of medications with an effect on the periodontium increased, while the variability within groups decreased with advanced training. Identifying systemic conditions that are not related to periodontal risk was consistently low among all groups. The greatest impact of training was seen on the students’ ability to make correct decisions about referral and treatment for the seven clinical cases. Although the magnitude of increase was fairly large among second-, third-, and fourth-year students, the mean of 4.6 out of 7 for fourth-year students reflects that, on average, students missed correct treatment or referral on more than two of the seven cases.
Dental students’ mean confidence, beliefs, and knowledge subscale scores and correct case decisions, by class
Finally, linear regression was used to determine if confidence in knowledge, belief in periodontal importance, knowledge of risk factors, knowledge of medications with an effect on the periodontium, and correct identification of systemic conditions were predictive of the number of correct case decisions for the seven cases. Results of the linear regression modeling with conditional backwards elimination (with removal set at 0.10) showed that the model with three predictors—confidence in knowledge, knowledge of risk factors, and knowledge of medications with an effect on the periodontium—was predictive of improved referral decision making. Model results are shown in Table 5. Each unit increase in confidence in knowledge resulted in a 0.7 increase in the number of cases correctly identified as needing referral. Knowledge of risk factors and knowledge of medications with an effect on the periodontium were statistically significant predictors of increasing the number of cases correctly referred. The model R=0.56 explained approximately 31 percent of variance in number of cases correctly referred. Variables excluded from the model were belief of periodontal importance and correct identification of systemic conditions.
Linear regression model predicting number of appropriate referrals on cases
Discussion
In 2006, the AAP established guidelines that address periodontal treatment by the periodontist alone or in co-management with the general dentist.2 These guidelines discriminated between patients who have periodontal disease alone and those who have periodontal disease in association with systemic conditions. The guidelines also identified medical and behavioral factors that increase the risk of periodontal disease, including tobacco use, drug-induced gingival conditions, and compromised immune systems. However, guidelines alone are not sufficient for clinical decision making as they cannot replace the practitioner’s knowledge, skills, and abilities. Because of the complexity of managing periodontal disease as a chronic condition, there is no “one size fits all” treatment plan for all patients. Linden found that considerable variation existed among general dentists in relation to referral patterns for specialist periodontal advice and treatment.19 Diagnosis, treatment, and referral decisions continue to present significant challenges to general dentists regardless of their experience level.
In our study, knowledge of risk factors, correct identification of systemic conditions, and knowledge of medications with an effect of the periodontium increased with advanced training. Risk factors accurately selected by at least 48 percent of students in the three classes were poorly controlled diabetes, ≥6 mm pockets posteriorly, and unresponsiveness to previous non-surgical periodontal therapy. We also found the proportion of students who selected Class II furcation as a referral indication increased as a function of advanced training, whereas the proportion who selected age thirty-nine or younger as a risk factor increased only slightly as a function of advanced training. Encouragingly, several of the “distracter” risk factors were chosen by less than 20 percent of the students and included high plaque score and age forty years or older. Previously, Williams et al. found with a similar list of risk factors that over 50 percent of dental students identified three of the six risk factors deemed most important by an expert panel and the “distracter” risk factors were selected by fewer than 10 percent of the students.18
The more experienced students in our study reported that they anticipated referring more difficult periodontal cases, with a clear trend towards differentiating between cases with and without co-existing systemic conditions. Previously, Williams et al. found 90 percent of dental students would be willing to refer cases of moderate to severe periodontitis.18 We found that second-year students overall were less likely to anticipate referring in all categories and did not differentiate between case type V with and without systemic conditions. Cobb et al. compared the characteristics of patients referred for periodontal therapy in 1980 versus those referred in 2000.17 Their results showed that the patients being referred had an increase in disease severity, numbers of missing teeth, and number of teeth treatment-planned for extraction over the two decades. Previous studies have demonstrated that periodontal referrals to a specialist are often made too late, which can have negative effects on the specialist’s ability to treat disease.16,17 These findings seem to reinforce the need for general dentists to make appropriate diagnostic and treatment decisions.
The greatest impact of training in our study was seen on the students’ ability to make correct decisions about referral and treatment for the seven clinical cases. Although the magnitude of increase was fairly large among the three classes, even the fourth-year students missed correct treatment or referral decisions on more than one-third of the cases. While the trend to answer more clinical scenarios correctly is encouraging, there remained a gap in knowledge and application of this knowledge to clinical situations. Among the several possible explanations for this gap are a lack of well-established practice guidelines and teaching methods that are more focused on knowledge acquisition than clinical decision making.
Current teaching methods may not be optimal for enhancing clinical decision making. One study found that 59 percent of dental education was teacher-dominated instruction in which the faculty member tells the student what to do or provides assessment of the patient’s condition without engaging the student.20 Only 2.2 percent of dental education, according to that study, was dedicated to techniques that encourage critical thinking. Dental students may also model their approach to clinical decision making after their instructors by focusing on instructor-specific strategies for addressing clinical cases instead of learning accepted practice and evidence-based diagnostic and treatment criteria.21 Lee et al. suggested that dental education programs need to assess how curricula prepare students to make proper and timely periodontal referrals as well as how students develop competence in this area.15 Not only do students need a strong fundamental base of knowledge in periodontal disease, including its link with systemic disease and the associated risk factors; they need to be able to critically utilize this information and apply it to clinical cases.
Finally, we sought to identify factors affecting clinical decision making. Confidence in knowledge, knowledge of risk factors, and knowledge of medications with an effect on the periodontium were predictive of improved referral decision making. The model explained 31 percent of the variance in the number of cases correctly referred, indicating other factors were affecting clinical decision making. Belief of periodontal importance and correct identification of systemic conditions associated with periodontal disease did not improve the accuracy of the model. As expected, confidence in knowledge increased with increased training, consistent with a previous study.18 Darby et al. surveyed 281 general dentists and found that most felt confident in diagnosing and treating gingivitis and initial periodontitis; however, only about one-third (31.7 percent) were confident treating advanced periodontitis, and 19.5 percent were confident treating aggressive periodontitis.22 We need to reassess our approach to dissemination of information, teaching methods, and knowledge applied to critical decision making with regard to periodontal disease. Also, there is a need to further develop and implement clinical guidelines if we are to close the gap and help our students develop the ability to determine the appropriate treatment and referral for their periodontal patients.
One potential limitation of this study is the variable response rate between classes. The fourth-year students had 69 percent of the entire class participating, whereas the second- and third-year students had over 90 percent participating. The timing of data collection corresponded to the very end of the semester, and many graduating fourth-year dental students were absent from class when the data were collected. It is possible that students not present in class were different from those who attended class, and this may have resulted in a biased sample. A future study should consider the timing of data collection with respect to class attendance. This study was completed at one dental school and involved only the dental classes of 2012, 2013, and 2014. The results of this study thus cannot be generalized to every second-year, third-year, and fourth-year dental class. Also, this study being done at only one institution limits the application of these findings to other institutions since periodontal curricula, periodontal faculty, and dental students vary from one school to another.
Conclusion
In spite of the limitations of the study, the following conclusions can be made. The students’ confidence in knowledge, knowledge of risk factors, correct identification of systemic conditions influencing referral, and knowledge of medications with an effect on the periodontium increased with advanced training. Their confidence in knowledge, knowledge of risk factors, and knowledge of medications with an effect on the periodontium were predictive of improved referral decision making ability. Increased training affected the students’ ability to make correct decisions about referral and treatment on clinical case scenarios. However, the fourth-year students on average still missed correct treatment or referral on more than two of the seven clinical cases. The more experienced students reported that they anticipated referring the more difficult cases, with a clear trend differentiating between cases with and without systemic conditions. This study suggests that dental school curricula should emphasize more clinical decision making with respect to treatment and referral criteria in managing periodontal patients.
Acknowledgments
This research was supported by the University of Missouri-Kansas City School of Dentistry Summer Scholars Program.
REFERENCES
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