A Nonsurgical Endodontics Relational Research Database: The Initial Six Years of Experience

Milieu in Dental School and Practice A Nonsurgical Endodontics Relational Research Database: The Initial Six Years of Experience Mian K. Iqbal, B.D.S., D.M.D., M.S.; Deborah Gortler Shukovsky, D.M.D.; Steven Wong, D.D.S.; Gayatri Vohra, D.D.S. Abstract: The purpose of this study was to report results of the initial six years of experience utilizing a nonsurgical root canal treatment (NSRCT) database; to compare patient characteristics, operative procedures, and patient outcomes observed in the database to those observed in other studies; and to discuss the potential benefits of a clinical endodontic database. A total of 7,372 NSRCT cases performed by endodontic residents at the University of Pennsylvania from 2000 to 2006 were evaluated. The odds ratio (OR) for caries and trauma being causative agents for NSRCT in 22 year-olds was 1.4 and 6.7 times, respectively, greater than similar odds in 51+ year-olds. The odds for younger patients presenting with the diagnosis of symptomatic irreversible pulpitis were two times greater than for their older counterparts, who were more likely to present with a diagnosis of pulp necrosis. The reasons necessitating NSRCT were most often caries (57.8 percent) and, second, inadequate prior root canal treatment (22.8 percent). The tooth most commonly treated was the mandibular first molar (20.1 percent). Procedural errors were found in 6.1 percent of cases and were more likely to occur in mandibular molars vs. maxillary molars. Dr. Iqbal is Assistant Professor-Clinician Educator, Director of the Postgraduate Program in Endodontics, and Director of Graduate Dental Education, and Dr. Shukovsky, Dr. Wong, and Dr. Vohra are Residents all in the Department of Endodontics, School of Dental Medicine, University of Pennsylvania. Direct correspondence and requests for reprints to Dr. Mian K. Iqbal, Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Robert Schattner Center, Room W8 Evans Building, 240 South 40 th Street, Philadelphia, PA 19104-6030; 215-898-4617 phone; 215-573-2148 fax; miqbal@pobox.upenn.edu. Key words: etiological factors, endodontic treatment, complications, procedural errors, incidence of NSRCT, graduate endodontics, relational research database Submitted for publication 10/2/07; accepted 4/28/08 Many studies have been performed to look at the incidence and distribution of endodontic treatment and outcomes. 1-5 These studies mainly obtained clinical data from patients charts, a process that can often be laborious and prone to errors. The availability of powerful personal computers and software packages has opened up the possibility for clinicians to consider purpose-built endodontic research databases. The development of such relational databases can allow a more effective measurement of endodontic outcomes with the help of an accurate, prospective clinical database over time. Recently, a number of epidemiological studies have measured selected endodontic outcomes following initial nonsurgical root canal treatment (NSRCT) procedures using large insurance company databases. 6-8 However, these databases are purposebuilt for insurance and may not contain the clinical data necessary for research purposes. To help resolve the problems associated with prospective data collection, the first author (MKI) has developed a computerized, relational research database for NSRCT procedures that facilitates the measurement of endodontic incidents and outcomes. Over a six-year period, feedback from endodontic residents and faculty and analysis of the database have led to the continued evolution of an effective database that may be used as a tool for clinical research in endodontics. This study was undertaken to report the results of the initial six years of experience with a nonsurgical endodontics database; to compare patient characteristics, operative procedures, and patient outcomes observed in the database to those observed in other studies; and to discuss the current shortcomings and potential benefits of a clinical endodontic database. 1058 Journal of Dental Education Volume 72, Number 9

Methods and Materials The database began as a tool to facilitate the collection and retrieval of clinical parameters for research in endodontics. The endodontic chart used by the endodontic residents was the model for inception of the database. The endodontic database named PennEndo database was developed with the help of FileMaker software (Santa Clara, CA). The database was designed to be easily utilized by busy endodontic residents in clinical practice. A point-and-click approach was used with dropdown boxes and menus for diagnoses, procedures, and procedural errors. Preselected values for diagnoses and procedural errors maintain data integrity and facilitate data entry speed. The endodontic program at the University of Pennsylvania has a total of sixteen residents in a two-year program. To address the possibility of high user volume, client-server methodology was implemented. This includes the use of a server to store the database, easily accessed by the resident s laptop via a network. However, during the later period, FileMaker software was installed on the residents computers, allowing them to maintain their own database and then download it to the main server. The security in the database was implemented at the user level with passwords and preferences assigned to each endodontic resident according to restrictions set up by a system administrator. The database located on a file server was made available to other users only via the local area network. The application was written for Macintosh operating system; however, it was compatible with Windows operating system as well. The PennEndo database became operational in September 2000, at which time it was opened to endodontic residents to enter their clinical endodontic data related to cases completed during their residency. The endodontic residents used the software to submit a common set of data regarding patients demographics, preoperative pain history, clinical examination and test results, clinical signs and symptoms, intraoperative procedures and events, and postoperative outcomes for all patients undergoing nonsurgical root canal treatment. The groups of cases and controls were studied to assess exposure to a suspected causative factor. Chi-square tests were used to determine the significance at p<0.05 level, and the odds ratios for different variables were determined at 95 percent confidence intervals. Results The residents had no problem learning the database program. They were able to generate reports on their data, which further encouraged them to continue accurate entry of clinical parameters into the database. The residents were calibrated for data entry during their orientation to the database and then subsequently during their monthly academic reviews with the program director. A periodic analysis of data for research and administrative purposes led to the addition of more data parameters for a wider capture of prospective clinical data. Between September 2000 and September 2006, thirty-six endodontic residents recorded preoperative, intraoperative, and postoperative data on a total of 7,372 patients undergoing NSRCT. Patients ages ranged from seven to ninety-one years and included tooth numbers 1 to 32. The most commonly treated tooth still remains the mandibular first molar followed by the maxillary first molar (Figure 1). A separate analysis indicated that the odds for mandibular first molar receiving NSRCT were 1.47 times greater than those for a maxillary first molar (CI 1.35 to 1.61). Causative factors for NSRCT are shown in Figure 2, indicating that caries still remains by far the largest factor for root canal treatment (RCT) in our population cohort. Further analysis indicated that the odds for caries being the causative factor for NSRCT were 5.6 times greater than those of prior RCT (CI 5.15 to 5.99). The causative factors are stratified according to age in Table 1. A comparison of odds ratios for different causative factors between 22 year-olds and 51+ year-olds is shown in Table 2. Caries and trauma were more common causative factors for NSRCT in younger patients, while prior RCT was more common in the older group of patients. A patient s age group correlated with pulpal diagnosis is depicted in Table 3. The results show decreasing incidence of symptomatic irreversible pulpitis as the age increases. According to the results, 22 year-old patients are 1.92 times more likely to suffer from symptomatic irreversible pulpitis when compared to 51+ year-old patients. Conversely, 22 year-olds were 0.74 times less likely to report with necrosis of the pulp compared to 51+ year-olds (Table 2). Procedural errors during treatment totaled 6.1 percent in the dataset. These included fractured September 2008 Journal of Dental Education 1059

Figure 1. Incidence (%) of NSRCT according to location Figure 2. Causative factors for root canal treatment 1060 Journal of Dental Education Volume 72, Number 9

Table 1. Causative factors stratified according to age groups Age (years) Caries Prior RCT Trauma Total* 22 Count 932 151 112 1,332 % within age 70.0% 11.3% 8.4% 100.0% 23 36 Count 839 339 32 1,382 % within age 60.7% 24.5% 2.3% 100.0% 37 50 Count 778 321 16 1,319 % within age 59.0% 24.3% 1.2% 100.0% 51+ Count 654 322 16 1,268 % within age 51.6% 25.4% 1.3% 100.0% Total Count 3,203 1,133 176 5,301 average % 60.4% 21.4% 3.3% *The factors idiopathic, intentional RCT, and patients with unreported causative factors are included in this total, although they are not shown on the table. instruments, root canal overfillings, perforations, ledge formation, and sodium hypochlorite accident. These errors were mostly brought about by the treating endodontic residents, although some cases were referred to the endodontic clinic after a procedural error occurred elsewhere. A breakdown of the procedural errors data is shown in Figure 3 and Table 4. A comparison of odds ratios of different procedural errors between maxillary and mandibular molars is shown in Table 5. According to the results, the mandibular second molar followed by the mandibular first molar showed the highest incidence of instrument separation. However, no statistically significant difference between these two teeth was noted in the odds for instrument separation. Flare-ups and fracture of instruments were less likely to take place in maxillary vs. mandibular second molars. Similarly, overfills were less likely to take place in maxillary first molars compared to mandibular first molars. Perforations constituted 21 percent of total procedural errors, which translates to an overall incidence of 1.28 percent in the dataset. A higher percentage of mandibular first molars was perforated; however, no statistically significant difference in the odds for perforation between mandibular and maxillary molars was noted. The referral base is shown in Figure 4. Further analysis of this data showed that the most commonly treated teeth from outside referrals (22.1 percent) and during emergency visits (30.3 percent) were mandibular first molars. The tooth most often referred from the pedodontic clinic was the maxillary first molar (22.1 percent). Table 2. A comparison of causative factors and pulpal diagnosis between 22 year-olds and 51+ year-olds Discussion OR 95% CI Causative Factor Prior RCT 0.42 0.34 to 0.51 Caries 1.43 1.28 to 1.59 Trauma 6.68 4.00 to 11.31 Pulpal Diagnosis Symptomatic irreversible pulpitis 1.92 1.65 to 2.24 Necrosis 0.74 0.63 to 0.87 OR=odds ratio CI=confidence interval Only statistically significant results (p<0.05) are shown. A number of studies have confirmed that more endodontic treatment is being provided to older patients. 3,9 The mean age of the patients reported in our study (37 years ±18) is close to an average age of forty, which was reported by a similar study conducted at a graduate endodontic program. 2 The incidence of root canal treatment reported in our study was similar to that reported in previous studies, but with some differences. The most commonly treated tooth in our dataset was the mandibular first molar, which is similar to a number of previous studies. 1,2,5 Hull et al. 10 found similar results and additionally showed that maxillary first molars were the second most commonly treated teeth. September 2008 Journal of Dental Education 1061

Table 3. Percentages of pulpal diagnostic categories stratified according to age group Age (Years) Previous RCT Necrosis Asymptomatic Symptomatic Total* Irreversible Irreversible Pulpitis Pulpitis 22 Count 164 342 208 600 1,332 % within age 12.3% 25.7% 15.6% 45.0% 100.0% 23 36 Count 372 293 135 558 1,382 % within age 26.9% 21.2% 9.8% 40.4% 100.0% 37 50 Count 335 330 157 474 1,319 % within age 25.4% 25.0% 11.9% 35.9% 100.0% 51+ Count 329 391 217 312 1,268 % within age 25.9% 30.8% 17.1% 24.6% 100.0% Total Count 1,200 1,356 717 1,944 5,301 average % 22.6% 25.6% 13.5% 36.7% *The factors idiopathic, intentional RCT, reversible pulpitis, and patients with unreported diagnosis are included in this total, although they are not shown on the table. Figure 3. Percentages of reported procedural errors The results of our study indicate that caries is the main causative factor in root canal treatment. This could be explained by the fact that most of our patients are from low socioeconomic status, so they may have lower oral hygiene awareness and less access to routine dental care. It may also be explained by the fact that first molars erupt at an early age and are thus exposed to the oral cavity for a longer period of time than some other teeth. As a result, in our patient population, first molars have a higher likelihood of developing caries; if not appropriately monitored, these teeth may end up with pulpal involvement, necessitating root canal treatment. These results correspond to a number of studies reporting that root canal treatment was mostly performed in molar teeth with vital pulps and was often due to caries. 2,11,12 Inadequate prior RCT is the second most common causative factor for root canal treatment in our clinic (22.8 percent). This type of treatment is commonly referred to as nonsurgical root canal retreatment (NSRCRT). The percentage of NSRCRT cases performed in a specialty practice has been reported to be as high as 37 percent, 13 while in general dental practices it is performed in only 2 percent of the cases. 12 NSRCRT performed in private endodontic practices is reported in the range of 3 percent 14 to 32 percent. 15 The percentage of NSRCRT reported in this study is lower than those reported for private specialty practices. It has been reported that most pulpal breakdown in the elderly is without the classic symptoms of reversible and irreversible pulpitis. 16 The results 1062 Journal of Dental Education Volume 72, Number 9

Table 4. Percentage of procedural errors according to anatomical location Maxillary teeth MandibUlar teeth Molars Premolars Canines Laterals Centrals Molars Premolars Canines Incisors Procedural 3rd 2nd 1st 2nd 1st % % % 3rd 2nd 1st 2nd 1st % % Error (%) (%) (%) (%) (%) (%) (%) (%) (%) (%) Fractured instrument 1.7 6.0 15.5 1.7 4.3 1.7 5.2 15.5 0.9 22.4 16.4 6.9.9 0.9 0.0 Flare-ups 3.2 6.5 16.1 0.0 9.7 6.5 9.7 12.9 0.0 22.6 6.5 3.2 0.0 0.0 3.2 Overfill 0.0 16.0 8.0 0.0 5.3 6.7 5.3 2.7 0.0 18.7 33.3 1.3 0.0 0.0 2.7 Perforation 1.2 17.3 17.3 4.9 4.9 2.5 4.9 7.4 0.0 9.9 22.2 2.5 1.2 2.5 1.2 Short/blocked canals 1.1 11.2 15.7 5.6 2.2 9.0 2.2 7.9 0.0 13.5 21.3 3.4 0.0 3.4 3.4 Sodium hypochlorite accident 0 0 0 0 0 0 0 25 0.0 50.0 0.0 0.0 0.0 25.0 0.0 Table 5. A comparison of procedural errors between maxillary and mandibular molars Maxillary 1st vs. Mandibular 1st Molar Maxillary 2nd vs. Mandibular 2nd Molar Odds Ratio Confidence Interval Odds Ratio Confidence Interval Overfill 0.24 0.11 to 0.55 NS Flare-up 2.47 0.96 to 6.4 0.29 0.12 to 0.72 Fracture NS 0.29 0.12 to 0.72 NS=not significant of this investigation indicated that elderly patients were more likely to present with a diagnosis of pulpal necrosis, while the younger patients presented with the diagnosis of symptomatic irreversible pulpitis. These results are in agreement with the commonly held belief that teeth in elderly patients are more prone to necrosis. 17 Previous history of pain is an important diagnostic means of establishing the presence of destructive pulp pathology. 18 In this study, 43.1 percent of patients presented with pain; of these, 61 percent also stated a history of pain. A similar analysis reported the incidence of preoperative pain in 58.6 percent of patients. 2 The procedural errors reported in our study are low. A comparatively higher incidence of procedural errors during root canal instrumentation and obturation has been reported by other studies. 19,20 A 21 percent incidence of short-filled and blocked canals reported by our study compares favorably with the results reported in the literature. The incidence of ledged canals in undergraduate students and endodontists cases has been reported to be as high as 51.5 percent and 33.2 percent, respectively. 21 As shown in Table 4, short-filled and blocked canals were most commonly found in molars. These are most likely associated with increased curvatures found in the anatomy of both maxillary and mandibular molars. An analysis of a referral-based endodontic practice found perforations to be present in 5.4 percent of teeth. 13 A possible explanation for the variation among studies is the experience of the different operators involved in the study. In our study, mandibular second molars, followed by mandibular first molars, had the highest incidence of instrument separation. A previous analysis of the PennEndo database 22 found the overall incidence of instrument separation to be 1.6 percent, with a greater chance of separation in mandibular second molars. Such findings are not surprising, as September 2008 Journal of Dental Education 1063

Figure 4. Percentage of cases referred from different sources mandibular second molars often possess significant canal curvatures and canals that merge. Sodium hypochlorite can sometimes be inadvertently forced out of the apex of the tooth during irrigation of the root canal. As a result of this accident, the patient can experience immediate severe pain, swelling, and hemorrhage from the root canal. The results of this investigation show that these accidents mainly took place in the mandibular second molars and canines, while, in the maxillary arch, central incisors were mostly involved in these accidents. However, it is difficult to draw any conclusions because of the small number of sodium hypochlorite accidents reported in the database. An overfilling was defined as when the apical extent of gutta-percha extends beyond the radiographic apex of the tooth. The extrusion of sealer cement was not categorized as an overfilling. It was noted that the majority of the overfilled cases (33 percent) were in mandibular molars. These results are in partial agreement with Eleftheriadis and Lambrianidis, 23 who found that acceptable fillings were significantly greater in the anterior teeth than in premolars or molars. Our postgraduate clinic often receives cases with procedural errors from the undergraduate clinic and from outside referrals as well. Due to these compiling factors, our procedural errors percentage is 6.1 percent. The fact that all the root canal treatments in this study were performed by endodontic residents under the direct supervision of attending endodontists may explain the lower incidence of procedural errors. The development and implementation of a system for the management of clinical data remain challenging, expensive, and extremely time-consuming tasks. This study has a few limitations that deserve to be mentioned. Data collection by the treating institution or a resident may be a source of bias, as unfavorable outcomes tend to be underreported. A number of steps have been taken to ensure accuracy of data input. The program administrator periodically uses audits to assess the accuracy or representativeness of data submitted to the PennEndo database. In these audits, a group of endodontic residents charts are randomly selected, and the data in the charts are matched with that entered into the database. Data quality assurance strategies at the time 1064 Journal of Dental Education Volume 72, Number 9

of data entry (e.g., ranges of acceptable data values) have been included in the database. The perception that outcome data is useful in continuous quality improvement was validated by the experience gained through this PennEndo database study. For example, the endodontic residents discovered that a greater incidence of instrument separation occurs in the mandibular molars and therefore they take additional precautions when instrumenting the mesiobuccal canals of molars. The importance of maintaining the confidentiality of both patient-specific and resident-specific data was recognized from the outset. To protect patient confidentiality while allowing postoperative data to be linked to preoperative data at the patient-specific level, patients were assigned a chart number. No information that would reveal the identity of a patient, such as a name or social security number, was ever transmitted to the database. A computerized database is an instrument by which a department of endodontics may develop complete, accurate, prospective data sets for patients undergoing endodontic procedures. Such a database has many potential academic benefits, including the opportunity for faculty and endodontic residents to undertake outcomes-based research and the development of an evaluation system for endodontic residents, as well as the endodontics program, based on experience and clinical outcomes. Similarly, a number of quality assurance parameters can be obtained from the database with comparative ease. Although the current database reflects the clinical practice of endodontics, this database can easily be expanded to adopt new procedures or modified for other dental specialties. Conclusion The initial experience with PennEndo database demonstrates that it is technically possible to collect clinical data from a graduate endodontic program and report aggregated results. The PennEndo database thus has the potential to provide a practical means for tracking practice patterns and patient outcomes in a postgraduate endodontic program. This report illustrates how a clinical endodontic database designed and implemented by a postgraduate endodontic program can provide insights into patterns of practice and patient outcomes in real time. Clinical databases, such as PennEndo, are a comparatively inexpensive means of examining patient characteristics, operative procedures, and patient outcomes, thus enhancing the quality of care that is delivered. REFERENCES 1. Serene TP, Spolsky VW. Frequency of endodontic therapy in a dental school setting. J Endod 1981;7:385 7. 2. Saad AY, Clem WH. An evaluation of etiologic factors in 382 patients treated in a postgraduate endodontic program. Oral Surg Oral Med Oral Pathol 1988;65:91 3. 3. Manogue M, Martin DM. Changes in patient age and tooth distribution for root canal treatment in a teaching hospital over a 15-year period. Int Endod J 1994;27:148 53. 4. Bjorndal L, Reit C. The annual frequency of root fillings, tooth extractions, and pulp-related procedures in Danish adults during 1977 2003. Int Endod J 2004;37:782 8. 5. Wayman BE, Patten JA, Dazey SE. Relative frequency of teeth needing endodontic treatment in 3350 consecutive endodontic patients. J Endod 1994;20:399 401. 6. Caplan DJ, Weintraub JA. Factors related to loss of root canal filled teeth. J Public Health Dent 1997;57:31 9. 7. Lazarski MP, Walker WA 3rd, Flores CM, Schindler WG, Hargreaves KM. Epidemiological evaluation of the outcomes of nonsurgical root canal treatment in a large cohort of insured dental patients. J Endod 2001;27:791 6. 8. Salehrabi R, Rotstein I. Endodontic treatment outcomes in a large patient population in the USA: an epidemiological study. J Endod 2004;30:846 50. 9. Saunders EM, Saunders WP. Endodontics and the elderly patient. Restorative Dent 1988;4:4 9. 10. Hull TE, Robertson PB, Steiner JC, del Aguila MA. Patterns of endodontic care for a Washington state population. J Endod 2003;29:553 6. 11. Iqbal M, Kim S, Yoon F. An investigation into differential diagnosis of pulp and periapical pain: a PennEndo database study. J Endod 2007;33:548 51. 12. Bjorndal L, Laustsen MH, Reit C. Root canal treatment in Denmark is most often carried out in carious vital molar teeth and retreatments are rare. Int Endod J 2006;39:785 90. 13. Abbott PV. Analysis of a referral-based endodontic practice: Part 2. Treatment provided. J Endod 1994;20:253 7. 14. Boykin MJ, Gilbert GH, Tilashalski KR, Shelton BJ. Incidence of endodontic treatment: a 48-month prospective study. J Endod 2003;29:806 9. 15. Chen SC, Chueh LH, Hsiao CK, Tsai MY, Ho SC, Chiang CP. An epidemiologic study of tooth retention after nonsurgical endodontic treatment in a large population in Taiwan. J Endod 2007;33:226 9. 16. Michaelson PL, Holland GR. Is pulpitis painful? Int Endod J 2002;35:829-32. 17. Allen PF, Whitworth JM. Endodontic considerations in the elderly. Gerodontology 2004;21:185-94. 18. Seltzer S, Bender IB, Ziontz M. The dynamics of pulp inflammation: correlations between diagnostic data and September 2008 Journal of Dental Education 1065

actual histologic findings in the pulp. Oral Surg Oral Med Oral Pathol 1963;16:969 77. 19. Pettiette MT, Metzger Z, Phillips C, Trope M. Endodontic complications of root canal therapy performed by dental students with stainless-steel K-files and nickel-titanium hand files. J Endod 1999;25:230 4. 20. Greene KJ, Krell KV. Clinical factors associated with ledged canals in maxillary and mandibular molars. Oral Surg Oral Med Oral Pathol 1990;70:490 7. 21. Kapalas A, Lambrianidis T. Factors associated with root canal ledging during instrumentation. Endod Dent Traumatol 2000;16:229 31. 22. Iqbal MK, Kohli MR, Kim JS. A retrospective clinical study of incidence of root canal instrument separation in an endodontics graduate program: a PennEndo database study. J Endod 2006;32:1048 52. 23. Eleftheriadis GI, Lambrianidis TP. Technical quality of root canal treatment and detection of iatrogenic errors in an undergraduate dental clinic. Int Endod J 2005;38: 725 34. 1066 Journal of Dental Education Volume 72, Number 9