This study evaluated how the factors from case difficulty assessment by AAE were associated with operating time for single-visit nonsurgical endodontic treatments under GA. Among many clinical variables contributing to case difficulty, anatomical complexities of teeth were the main contributors to increasing operating time. So, our null hypothesis was rejected.
Operating time is a critical issue for practitioners, administrators, and third-party payers [12]. Previous studies determined factors affecting surgical duration to enhance the flow of operating rooms and working staff. Efficient scheduling can decrease expenditures by enhancing utilization of resources and minimizing overhead. In dentistry, a single practitioner mainly engages in an entire procedure with assisting staff at dental units. Therefore, a relatively smaller number of variables affect operating circumstances. From this point, case complexities can be a principal focus on time organization, staff stress, and financial management.
The administration of GA was inevitable for the study population, who could not comply with treatment because of intellectual and cognitive limitations. The authors had previously published studies on the quality assessment of endodontic treatment under GA [10, 11]. These studies validated the outcome assessments of single-visit endodontic and restorative treatments for patients with special needs and supported the treatment regimen under GA be encouraged. However, cost issues are inevitable in treatment planning and decision-making for special needs patients. Therefore, we attempted to introduce clinical time measurement as a treatment outcome, one of the most critical considerations in GA settings. In this study, the 198 cases of nonsurgical endodontic treatment of minimal to moderate or high difficulty were proportional (111 vs. 80). Across procedures, time-deciding factors were largely dependent on the case per se and minimally affected by other background issues. Furthermore, all treatments were completed by a single specialist who was accustomed to this clinical setting. Total treatment duration was relatively invariant: the SDs for mean operating time did not exceed 12 min for anterior teeth and 19 min for posterior teeth (Table 1). Nevertheless, high-difficulty cases required almost 150% more time to complete procedures than moderate-difficulty cases (Tables 3, 4).
Endodontic cases vary in complexity among dental practices. Many case-difficulty assessment forms have attempted to evaluate treatment complexity for practitioners and educators. On AAE assessment forms, a point system was introduced to assign a graded score according to the difficulty level. However, the weight of the value for an individual item in each category needs to be considered, since some items are more influenced by practitioner competence than others. In this study, complicated tooth anatomies were significant contributors to prolonged operations. Our multivariate analysis showed that high difficulty factors characterized by deformed crown shapes, deviated canal curvature, and/or indistinct canal path were strong predictors of increased time (Table 5). In a study of third molar extraction, anatomic variables were largely correlated with extraction time among many clinical factors that surgeons considered particularly important [13]. Patient demographics were minimally associated with operating difficulty, in accordance with our results. Often, surgeon stress level in operating rooms is quantified by numerical systems related to case complexity. It is encouraging that the subjective assessment of practitioner burden and the objective assessment of operating time correlated for more refined validation of case difficulty assessment.
Endodontic case difficulty levels have been used to evaluate quality outcomes for educational and referral purposes. For high difficulty cases, a higher number of mishaps and treatment visits occurred in undergraduate clinics [5] and more unacceptable outcomes were obtained from general practitioners [1]. In this study, the challenging conditions of difficult cases influenced operating duration and treatment outcomes, even for a well-experienced specialist. All cases with unacceptable levels of canal filling length and density belonged to the severe-difficulty category (data not shown) and required more than 150% of the time of cases with acceptable outcomes. This result showed that fulfillment of difficult cases was hard to achieve, although significant time and efforts were spent on completing treatment.
Among the factors of patient considerations included in Model 1 assessment, ability of mouth opening was only relevant in treatment under GA. Even using a mouth prop during procedures under GA, limited intraoral spaces impose difficulties on inserting and maneuvering intracanal instruments. However, other factors of patient considerations such as incompetent anesthesia, anxiousness, and gag reflex, did not affect procedural performance under GA administration. Moreover, of our study population, 63% had systemic disease, assigned with the American Society of Anesthesiologists (ASA) classification 2 or 3. Therefore, these cases were automatically subjected to the moderate (ASA 2) or high-difficulty category (ASA 3), regardless of the tooth conditions. We attempted to refine the assessment tool, so we analyzed it using Model 2 assessment that included more representative items in conventional practices (diagnostic and treatment considerations, and additional considerations). We finally obtained 34 minimal, 105 moderate, and 59 high-difficulty cases from Model 2 assessment, and a higher case difficulty resulted in a longer procedural duration for all types of teeth (Table 4). This result implied that in a conventional clinical setting, where relatively healthier patients are treated, tooth-related difficulty variables would have a clearer impact on operating duration. In another way, clinical factors such as pain control, anxiety, and mouth opening, which were minimally influential on treatment under GA, would be more related to operating time in treatment under local anesthesia. Although there are limitations in extrapolating this study’s outcomes to time prediction in a conventional clinical situation, it is clear that operating time will increase with the level of case difficulty regardless of clinical circumstances.
Conventionally, case complexity is considered in operating rooms from two perspectives, resource allocation and surgeon load. Risk and difficulty of endodontic treatment can also be evaluated by these aspects; objective measures of time spent and subjective measures of stress load. Therefore, in a future study, assessment of practitioner burden for difficult cases should be considered using time and stress measures [14]. Eventually, more advanced assessment tools can be enhanced for referral and education, furthermore, for other options such as financial reward and legal justification.
