Although researchers have made efforts to develop new technologies to improve diagnostic ability [17,18,19,20], periodontal diagnosis and classification are still formulated based on clinical and radiographic data collected by individual practitioners. A practitioners’ ability to interpret and integrate the data obtained and critical thinking skills for clinical reasoning yields meaningful periodontal decisions [21]. The purpose of this study was to examine the variations in periodontitis classification among dental practitioners with different postgraduate educational backgrounds using the current classification.
We found that there was a fair level of agreement among all participants and the agreement level was higher among the periodontal cohort than the nonperiodontal cohort when the current classification was employed (Fig. 1). Although fair to moderate agreement was obtained, the accuracy was not at the satisfactory level, ranging from 31 to 83% at the most (Table 4). Even for the most straightforward case from the investigators’ point of view (Case 3), the grading accuracy was 36%. For only two items out of eight, the periodontal cohort demonstrated significantly better accuracy in periodontitis classification (grading for Case 1 and staging for Case 3).
Grading, especially for new patients, could be challenging because dental practitioners often do not have previous periodontal records, such as CAL or RBL. Calculating the amount of CAL or RBL over 5 years, which was suggested as direct evidence in the current classification [8], is difficult. Instead, dental practitioners often use the %bone loss/age index as indirect evidence. The goal of incorporating grading is to estimate the future risk of periodontitis progression and responsiveness to standard therapeutic principles to guide the intensity of therapy and monitoring [11]. Grading is also designed for estimating the potential impact of systemic health on periodontitis to promote comanagement of patient health with medical teams [11]. Having an accurate grade influences the management of the case, including the treatment goal, strategy, treatment modalities and/or sequence.
Identification of risk factors for periodontal disease is also difficult regardless of the educational background, as indicated by the low level of accuracy and the lack of a significant difference in the recognition of risk factors for the two cases (Cases 1 and 2) among the two cohorts. Risk factors, when present in an individual, increase the chance of developing the disease by modifying host responses to the etiology, bacterial plaque, in periodontal disease [22]. Although the guideline stated diabetes and smoking as a risk factor, many responders answered hypertension as a risk factor for periodontitis. This may indicate that the concept of risk factors for periodontal disease is not well understood among many participating dental practitioners in this study. Since risk factors play a role as grade modifiers in the grading system, emphasis on risk factors for periodontal disease in dental education is recommended.
Since the current classification was published in 2018, many dental practitioners with other education backgrounds were not familiar with the classification. Interestingly, when the periodontal background was controlled for, some of the correlations between familiarity and accuracy for staging and grading were even negative for the nonperiodontal cohort (Table 5). This implies that dental practitioners who were not aware of or were not using the current classification performed well in periodontitis classification when the guidelines were provided. It is noteworthy that this result is only generalizable for the population of dental practitioners who have nonperiodontal backgrounds and have never used the current classification. Among this population, the familiarity level is not a key to classify periodontitis cases.
A recent publication emphasized that Stage is a patient-based, not a tooth-based concept [23]. The authors acknowledged that there is a gray zone for the clinicians to use clinical judgement for certain patient cases. Therefore, obtaining all necessary information including patient’s medical history, radiographs, and a full mouth periodontal charting is important [23]. The critical information for clinicians to determine staging and grading for patients is CAL, etiologies for CAL, % RBL, and patient’ age, which dental practitioners should be able to interpret.
The generalizability of our study results is limited due to a few factors. The sample size was relatively small. Only PG dental residents from the UMSOD were included in the nonperiodontal cohort while the periodontal cohort was comprised from both universities. All dental education for undergraduate and postgraduate training in the US should follow the Commission on Dental Accreditation guideline. Therefore, the training for specialists in both universities is similar although they are not the exact same; PG periodontics programs in both universities use the current periodontitis classification. The PG dental residents from the UMSOD in the nonperiodontal cohort was included because the PI confirmed that they did not receive the formal education on the current periodontitis classification, while PG dental residents in some programs from the LLUSD have been implementing the current classification in their training. The number of cases and items for each case were small in the questionnaire. While the three patient cases were meant to represent different scenarios with the investigators’ intention, more cases and items related to each case are necessary to cover contents related to periodontal diagnosis and classification such as clinical and radiographic data assessments, local contributing factors for periodontal disease, and occlusal evaluation.
