The latest in endodontic research

Dr. Kishor Gulabivala presents the latest literature.

Keeping you up-to-date with the most relevant research age and timing of pulp extirpation as major factors associated with inflammatory root resorption in replanted permanent teeth Bastos JV, Ilma de Souza Cortes M, Andrade Goulart EM, Colosimo EA, Gomez RS, Dutra WO Journal of Endodontics (2014) 40(3): 366-71

Abstract
Aim: External root resorption (ERR) is a serious complication after replantation, and its progressive inflammatory and replacement forms are significant causes of tooth loss. This retrospective study aimed to evaluate the factors related to the occurrence of inflammatory ERR (IERR) and replacement ERR (RERR) shortly after permanent tooth replantation in patients treated at the dental trauma clinic at the School of Dentistry, Federal University of Minas Gerais, Belo Horizonte, Brazil.

Methodology: Case records and radiographs of 165 patients were evaluated for the presence, type, and extension of ERR and its association with age and factors related to the management and acute treatment of the avulsed tooth by using the logistic regression model.

Results: The patient’s age at the moment of trauma had a marked effect on the ERR prevalence and extension. The patients older than 16 years at the moment of trauma had less chance of developing IERR and RERR (77% and 87%, respectively) before the pulp extirpation, regardless of the extension of the resorption. The patients older than 11 years of age at the moment of trauma showed the lowest indices of IERR (P = .02). Each day that elapsed between the replantation and the pulp extirpation increased the risk of developing IERR and RERR by 1.2% and 1.1%, respectively, and also raised the risk of severe IERR by 0.5% per day.

Conclusion: The risk of mature teeth developing severe IERR before the onset of endodontic therapy was directly affected by the timing of the pulpectomy and was inversely proportional to age. Systemic antibiotic therapy use had no effect on the occurrence and severity of IERR in mature teeth. The occurrence of RERR before the onset of endodontic treatment stimulates further investigations of the early human host response to trauma and subsequent infection.

Evaluation of microsurgery with Super EBA as root-end filling material for treating posttreatment endodontic disease: a 2-year retrospective study  Li H, Zhai F, Zhang R, Hou B Journal of Endodontics (2014) 40(3): 345-50

Abstract
Aim: This retrospective study assessed the effects of microsurgical treatment of posttreatment endodontic disease using Super EBA (Bosworth, Skokie, IL) as a root-end filling material and evaluated the potential prognostic factors in relation to outcome.

Methodology: Data were collected from patients diagnosed with posttreatment endodontic disease who then underwent endodontic microsurgery between April 2007 and October 2010. The effect was evaluated 2 years after the operation. Surgical procedures were performed by a single endodontic specialist. After surgery, operation records were recorded including preoperative, intraoperative, and postoperative factors from the clinical and radiographic measures. For statistical analysis of the predisposing factors, the dependent variable was the dichotomous outcome (i.e., success versus failure).

Results: Eighty-two patients with 101 treated teeth met the inclusion criteria. The recall rate was 87.2%. Of these microsurgically treated cases, the overall healing rate was 93.1%. At the 0.05 significance level, age, sex, tooth position, size of periapical radiolucency, biopsy result of periapical lesion, and presence of a sinus tract appeared to have no significant effects on the outcome (P > .05).

Conclusion: Microsurgical endodontic treatment using Super EBA as the root-end filling material is a favorable option for post-treatment endodontic disease.

Comparison of clinical outcomes of endodontic microsurgery: 1 year versus long-term follow-up
Song M, Nam T, Shin SJ, Kim E Journal of Endodontics (2014) 40(4): 490-4

Abstract
Aim: The purpose of this study was to examine and compare the clinical outcome of endodontic microsurgery after 1 year of follow-up and over a period of 4 years.

Methodology: The database of the department of conservative dentistry, Yonsei University, Seoul, South Korea, was searched for patients who had undergone endodontic microsurgery and had been evaluated 1 year after surgery and over a period of 4 years. Two examiners independently evaluated the postoperative radiographs taken 1 year after surgery and over a period of 4 years using Rud’s criteria. To analyze and compare the success rate based on the observation period, the McNemar test was performed with a significance level of 0.05.

Results: The study included 115 cases. Using Rud’s criteria, the overall success rate of cases with four or more years of follow-up was 87.8% compared with 91.3% at 1 year of follow-up. There was no significant difference between the follow-up periods (P = .344).  

Conclusion: There was no significant difference in the clinical outcome after endodontic microsurgery when comparing 1-year follow-up periods with longer follow-up periods.

Traditional endodontic surgery versus modern technique: a 5-year controlled clinical trial
Tortorici S, Difalco P, Caradonna L, Tete S Journal of Craniofacial Surgery (2014) 25(3): 804-7

Abstract
Aim: In this study, the outcomes of traditional apicoectomy versus modern apicoectomy were compared by means of a controlled clinical trial with a 5-year follow-up.

Methodology: The study investigated 938 teeth in 843 patients. On the basis of the procedure performed, the teeth were partitioned into three groups. Differences between the groups were the method of osteotomy (type of instruments used), type of preparation of retrograde cavity (different apicoectomy angles and instruments used for root-end preparation), and root-end filling material used (gray mineral trioxide aggregate or silver amalgam).

Outcome (tooth healing) was estimated after 1 and 5 years, postoperatively.
Results: Clinical success rates after 1 year were 67% (306 teeth), 90% (186 teeth), and 94% (256 teeth) according to traditional apicoectomy (group one), modern microsurgical apicoectomy using burns for osteotomy (group two), or using piezo-osteotomy (group three), respectively. After 1 year, group comparison results were statistically significant (P < 0.0001). Linear trend test was also statistically significant (P < 0.0001), pointing out larger healing from group one to group three. After 5 years, teeth were classified into two groups on the basis of root-end filling material used. Clinical success was 90.8% (197 teeth) in the silver amalgam group versus 96% (309 teeth) in the mineral trioxide aggregate group (P < 0.00214). Multiple logistic regression analysis found that surgical technique was independently associated to tooth healing.  

Conclusion: Modern apicoectomy resulted in a probability of success more than 5 times higher (odds ratio, 5.20 [95% confidence interval, 3.94-6.92]; P < 0.001) compared with the traditional technique.

Clinical decision making for a tooth with apical periodontitis: the patients’ preferred level of participation
Azarpazhooh A, Dao T, Ungar WJ, Chaudry F, Figueiredo R, Krahn M, Friedman S Journal of Endodontics (2014) 40(6): 784-9

Abstract
Aim: To effectively engage patients in clinical decisions regarding the management of teeth with apical periodontitis (AP), there is a need to explore patients’ perspectives on the decision-making process. This study surveyed patients for their preferred level of participation in making treatment decisions for a tooth with AP.

Methodology: Data were collected through a mail-out survey of 800 University of Toronto Faculty of Dentistry patients, complemented by a convenience sample of 200 patients from 10 community practices. The Control Preferences Scale was used to evaluate the patients’ preferences for active, collaborative, or passive participation in treatment decisions for a tooth with AP. Using bivariate and logistic regression analyses, the Gelberg-Andersen Behavioral Model for Vulnerable Populations was applied to the Control Preferences Scale questions to understand the influential factors (P < .05).

Results: Among 434 of 1,000 respondents, 44%, 40%, and 16% preferred an active, collaborative, and passive participation, respectively. Logistic regression showed a significant association (P < .025) between participants’ higher education and preference for active participation compared with a collaborative role. Also, immigrant status was significantly associated with preference for passive participation (P = .025).

Conclusion: The majority of patients valued an active or collaborative participation in deciding treatment for a tooth with AP. This pattern implied a preference for a patient-centered practice mode that emphasizes patient autonomy in decision making.

Current trends in endodontic treatment by general dental practitioners: report of a United States national survey
Savani GM, Sabbah W, Sedgley CM, Whitten B Journal of Endodontics (2014) 40(5): 618-24

Abstract
Aim: In the United States, almost 70% of root canal treatment (RCT) is performed by general dentists (GPs), yet little is known about their treatment protocols.

Methodology: A paper survey was mailed to 2,000 United States GPs with questions about the types of endodontic cases treated, routine treatment protocols, use of newer technologies, and endodontic continuing education (CE).  
Results: Completed surveys were returned by 479 respondents (24%). GPs who perform RCT (84%) reported providing anterior (99%), bicuspid (95%), and molar (62%) RCT and retreatment (18%). Rubber dam was used always (60%), usually (16%), sometimes (13%), and never (11%). Newer technologies used by GPs included digital radiography (72%), magnification (80%), electronic apex locator (70%), and nickel-titanium rotary instrumentation (74%). Compared with GPs with more than 20 years of experience, those in practice for less than 10 years were more likely to use rubber dam (P < .05), nickel-titanium rotary instrumentation (P < .001), apex locators (P < .001), and magnification (P < .01). In contradistinction, GPs in practice for more than 20 years were more likely to perform retreatments (P < .05). Women were less likely to perform retreatment or molar RCT (both P < .05). GPs with more than 5 hours of CE were more likely to use rotary instrumentation (P < .001), irrigant activation devices (P < .01), and apex locators (P < .001) and perform molar RCT (P < .001) and retreatment (P < .05), but no more likely to use rubber dam.   

Conclusion: Recent GP graduates (less than 10 years) were more likely to adopt new technologies and use rubber dam than those who practiced for more than 20 years. More experienced GPs were more likely to take on complicated cases than those with fewer years of practice. There was no association between hours of CE and compliance with rubber dam usage.

A study of the endodontic workforce in Australia in 2010
Motearefi P, Abbott PV International Endodontic Journal (2014) 47(5): 477-86

Abstract
Aim: To investigate the current workforce situation for specialist endodontists in Australia to help plan for the future of the specialty.

Methodology: An online questionnaire was sent via email to all registered endodontists that were identified from the Australian and New Zealand Academy of Endodontists database and the Australian Dental Association Directory. The questionnaire comprised questions on demographic characteristics, practice type, teaching and research activities, busyness, and expected retirement time. All results were transferred to a statistical software program (SPSS v.19) for analysis.  

Results: The response rate was 50%. The majority of respondents (84%) were male. The most common (64.5%) type of practice was single-location private practice. The majority (93%) of endodontists are located in state capital cities. Many respondents (61%) did some teaching. A minority of respondents (16%) were currently involved in research. The next available non-emergency appointment was more than 1 week away for 84% of respondents. More than half the respondents (52%) do not have allocated time for emergency patients. Only 18% of respondents plan to retire in the next 5 years and another 15% within 5 to 10 years. Although 58% of practice owners indicated that they have sufficient space and facilities to employ another endodontist, only 33% would consider employing or having an associate join their practice.   

Conclusion: Most endodontists in Australia are male private practitioners who work in a single state capital city location. Many teach, but few carry out research. They are fully booked with routine patients and have no spare scheduled appointments for emergencies; these have to be seen at the end of the day, or between scheduled patients. There will be a steady rate of retirement in the future, and only just enough newly qualified endodontists are being trained to maintain the specialty workforce at current levels.

Cavitation measurement during sonic and ultrasonic activated irrigation
Macedo R, Verhaagen B, Rivas DF, Versluis M, Wesselink P, van der Sluis L Journal of Endodontics (2014) 40(4): 580-3

Abstract
Aim: The aims of this study were to quantify and to visualize the possible occurrence of transient cavitation (bubble formation and implosion) during sonic and ultrasonic activated irrigation (UAI).
Methodology: The amount of cavitation generated around several endodontic instruments was measured by sonochemi-
luminescence dosimetry inside four root canal models of human dimensions and varying complexity. Furthermore, the spatial distribution of the sonochemiluminescence in the root canal was visualized with long-exposure photography.  
Results: Instrument oscillation frequency, ultrasonic power, and file taper influenced the occurrence and amount of cavitation. In UAI, cavitation was distributed between the file and the wall extending beyond the file and inside lateral canals/isthmuses. In sonic-activated irrigation, no cavitation was detected.   
Conclusion: Cavitation was shown to occur in UAI at clinically relevant ultrasonic power settings in both straight and curved canals but not around sonically oscillating instruments, driven at their highest frequency.

Free available chlorine concen-tration in sodium hypochlorite solutions obtained from dental practices and intended for endodontic irrigation: are the expectations true?
van der Waal S, Connert T, Laheij A, de Soet J, Wesselink P Quintessence International (2014) 45(6): 467-74

Abstract
Aim: Sodium hypochlorite (NaOCl) is an important tool in root canal disinfection although it is well-known that the shelf-life of NaOCl is limited. In this study, NaOCl solutions that were collected from dental practices and were intended for endodontic irrigation were investigated to see whether they contained the expected concentration of free available chlorine.

Methodology: NaOCl solutions were collected from dental practices. The concentration of available chlorine per sample was determined with iodometric titration, and the pH was measured. Each participating dentist completed a questionnaire that requested data on a range of issues relating to the assumed concentration of NaOCl and handling of the sample.  

Results: Eighty-four samples with questionnaires were received. NaOCl was purchased from supermarkets and drugstores (36%), dental suppliers (48%), or pharmacies (16%). The median expected concentration was 2% (n = 36). On average, 27% less available chlorine was measured than the dentist assumed was in the sample (P < .001). Fifteen per cent of samples contained less than 1% available chlorine, which is needed for tissue dissolution and disinfection. The average pH was 11.5.   

Conclusion: The greatest differences in concentrations were found in NaOCl sourced from supermarkets or drugstores. Future studies should elucidate the cause of this discrepancy. It is recommended to purchase NaOCl from professional suppliers, because this group showed the most reliable content of free available chlorine.