Skip to main content
e-mail Print Share
JADA Specialty Scan - Endodontics
Endodontics - A Quarterly Newsletter on Dental SpecialtiesJADA Specialty Scan

Middle mesial canals, isthmi and mandibular molars The template calls for the image at 225 by 175 but adjustments can be made within reason

A University of Florida College of Dentistry and Medicine study sought to clarify some inconsistencies in the dental literature and prevailing controversy associated with the middle mesial (MM) canal in the mesial root of the mandibular molars.

The study's 2 main aims centered on identifying the prevalence of a true MM canal and isthmus in the mesial root of mandibular molars and analyzing the morphology of middle mesial canals and isthmi in the mesial root of mandibular molars. Results were published in the July Journal of Endodontics.

"It has been shown that there is a strong relationship between the presence of untreated canal space and apical periodontitis," the researchers wrote. "Therefore, a thorough knowledge of the internal root canal anatomy is required to achieve the main objective of endodontic treatment, which is to prevent or heal apical periodontitis. However, the variability in number and configuration of the canals can pose some clinical challenges and prevent the clinician from achieving this goal."

Study materials included a sample of cone-beam computed tomographic (CBCT) images obtained from a population in Florida and retrospectively evaluated. The 90 limited field of view CBCT scans were of 122 mature mandibular first and second molars with no previous root canal treatment, no root resorption, and intact crowns.

"During examination of the teeth, the number of roots, the number of root canals in the mesial root, and the configuration of the root canal system in the mesial root were determined and recorded,” researchers wrote. "In the axial view, an isthmus was recorded when a narrow ribbon-shaped communication was visualized between the [mesiobuccal] MB and [mesiolingual] ML canals. The MM canal was recorded when a radiolucency with a distinct round cross section was visualized between the MB and ML canals regardless of the presence or absence of an isthmus. The findings were classified into 6 categories based on the location of the MM canal/isthmus beginning and end."

Researchers entered collected data in Excel and performed analysis with the aid of Statistical Package for Social Sciences version 22. They compared differences in the prevalence of the MM canal and isthmus using the x2 test. Level of significance was set at P < .05.

Researchers determined that 20 of the 122 teeth had true MM canals. Middle mesial canals were more prevalent in first molars at 26% than in second molars at 8%. Isthmi in the mesial roots had a frequency of 64.7%. Researchers concluded that these findings demonstrate a high prevalence of mandibular molars with MM canals or isthmi.

The significance of the study's findings, researchers concluded, is that they underscore need for the critical step of detecting and cleaning these areas during surgical root canal treatment. "The presence of a canal isthmus is one of the main causes of failure of nonsurgical and surgical endodontic treatments in mandibular molars," the authors wrote. "Isthmi or MM canals at the apex of the mesial root may act as portals of exit; therefore, detecting and cleaning these areas during surgical root canal treatment is a critical step."

Read the full article here.


Consulting Editor: Dr. Susan Wood
Diplomate, American Board of Endodontics


Cone-beam computed tomography in endodontics

Image of person filling an online survey

The relevance of cone-beam computed tomography (CBCT) among American Association of Endodontists members was the focus of clinical research that examined acceptance, accessibility, and usage of CBCT within the ranks of AAE via an online survey.

Researchers, who published the survey results in the May Journal of Endodontics, emailed the Qualtrics online survey to 3,076 active and resident AAE members in the U.S.

Said the researchers: "Besides its reliability and application for diagnosis, decision making, and treatment planning, CBCT imaging is receiving increasing recognition as a possible tool to use during actual endodontic treatment ... A number of investigations have looked into the acceptance and application of CBCT technology in different fields of dentistry, including its use in oral and maxillofacial surgery, orthodontics, dental education, and dental hospital settings. These data were mostly collected in the form of surveys or questionnaires. No similar data exist for endodontics."

Eight questions comprised the survey of AAE members. The questions centered on demographics, access to CBCT machines, field of view, frequency of use for particular applications, and, when CBCT wasn't used, reasons. For statistical analysis, researchers applied x2 tests using the Qualtrics online suite.

"Participants were asked their age, type of practice, years since graduating from an endodontic specialty program, and access to CBCT imaging for the participants' clinical practice … participants who did not use CBCT technology were asked the reasons for not using CBCT imaging in their clinical practice," the researchers wrote.

Response rate to the survey was 35.2%, with 1,083 participants having completed the survey. Most participants—90.12%—were part of a solo or group private practice. Most—80.30%—also had access to a CBCT unit. "Having no access to a CBCT unit was declared by 209 respondents (19.30%)," researchers said.

A significantly higher percentage of practitioners in a residency program (currently in endodontic residency) had access to a CBCT unit.

The survey revealed that for all applications, clinicians used CBCT imaging significantly more often if the CBCT unit was on site as opposed to when it was offsite.

"Regarding the question why participants would not use CBCT technology in their place of practice, 53.79% named cost as the reason, 8.29% lack of installation space, 21.09% stated that they did not think that this technology was a necessary benefit, and 16.82% stated other reasons," the researchers wrote.

Ultimately, the survey outcomes demonstrated a prevalence of CBCT technology application in endodontic practice. "However, in particular, the general comment section of the survey exhibited that there is still a gap in acknowledgment of its usefulness between clinicians.”

Read the full article here.

Video screen image of Dr. Robert Ritter

Leading clinician talks about self-adhesive cementation.

As a leading researcher in adhesive and cosmetic dentistry, Dr. Robert Ritter has researched, lectured, and published numerous articles on the topic. Listen to what he has to say here.



Preoperative prednisolone for irreversible pulpitis

Image of white pills

Dental researchers at Cairo University in Egypt investigated the pain relief efficacy of a single, preoperative dose of oral prednisolone on postoperative pain in patients with symptomatic irreversible pulpitis.

The clinical trial also measured the effect of the preoperative prednisolone administration on postoperative analgesic intake in the study patients. The results were online July 4 in International Endodontic Journal.

"Postoperative pain, which commences a few hours or days after treatment, is always an unpleasant experience for both patients and clinicians," wrote the researchers. "Thus, its prevention and management are of prime importance. Previous studies have reported that the prevalence of post-endodontic pain is 40% at 24 h[ours]."

The researchers indicate finding only 1 previous study that evaluated preoperative, single-dose oral prednisolone to treat postoperative pain. That inconclusive study specified a need for other clinical trials with more control of variables to limit bias and provide more reliable results.

The Cairo University study aimed to further "assess the effect of a single-dose, orally administrated, 40 mg prednisolone on postoperative pain after single-visit root canal treatment of teeth with symptomatic irreversible pulpitis." The study design was a single-center, randomized, parallel, 2-arm, double-blind clinical trial with an allocation ratio of 1:1. Four hundred patients from the outpatient clinic of the Department of Endodontics participated in the clinical trial from 2012 to 2014. They were between 18-35 years of age.

The independent Centre for Evidence-Based Dentistry, Cairo University, performed sequence generation and allocation concealment for the clinical trial. Through this process, patients were randomly divided into 2 groups. Group A received 40 mg of prednisolone and group B, the control, received a placebo dose. "All patients received the assigned premedication 30 minutes before the administration of local anesthesia administration by a nurse not involved in the study," according to researchers.

The clinical procedures subsequently involved anesthetizing each patient using 1.8 mL of local anesthesia Mepecaine-L. An additional cartridge was administered if any patient felt pain during access or instrumentation. "After access cavity preparation, the tooth was isolated with a rubber dam and working length was determined using an apex locator [and] then confirmed radiographically to be 1 mm short of the radiographic apex," the researchers wrote.

A chelating cream provided lubrication. Following root canal instrumentation using a rotary system according to the manufacturer's instructions, a final flush was performed and canals were then dried and treated via a modified single-cone technique. A cotton pellet was finally placed in the pulp chamber and the access cavity was restored with the temporary filling.

For pain measurement following the root canal treatment, each patient received a diary. Patients reported pain 6, 12 and 24 hours after the root canal treatment using a visual analogue scale. Also, each patient was dismissed with a placebo capsule, as an analgesic, and instructed to take it only in the presence of pain. If pain persisted after taking the placebo, the patient was instructed to contact the operator who would then prescribe an analgesic. Patients self-reported whether they took the placebo and whether they needed an analgesic. They returned their pain diary after 24 hours.

Results indicated that the prednisolone group had significantly lower pain intensity compared to the placebo group at 6, 12 and 24 hours. The incidence of both placebo and analgesic uptake was significantly less in the prednisolone group compared to the control group.

Researchers concluded that patients with symptomatic irreversible pulpitis benefit from a preoperative, 40 mg, single-dose of prednisolone to relieve pain up to 24 hours after a single-visit root canal treatment.

Read the full article here.


Avulsed tooth storage media and periodontal cells

Illustration of molar in a glass of water

A Marquette University (Milwaukee, WI) study of commercial storage media for avulsed teeth measured the products’ ability to support viability and proliferative capacity of human periodontal ligament fibroblast (HPDLF) cells at different time intervals.

According to the study authors, "The null hypothesis is that all the storage media are the same in maintaining the viability and proliferative capacity of HPDLFs and they are as detrimental to cells as water is at all time points."

The study, published online July 15 in International Endodontic Journal, assessed 3 popular commercial storage media regarding their ability to support HPDLF cell viability and proliferative capacity. The researchers used water as a storage medium for negative control and assessed cell viability at 0.5, 1, 3, 6, 12 and 24 hours at room temperature (22°C).

"Pure water has a hypotonic osmolality with 3-4 mOsm/kg and causes cell damage and lysis,” researchers wrote. “Replanting avulsed teeth stored in tap water resulted in a high incidence rate of replacement resorption. Water, therefore, is considered as the least favorable tooth storage medium and should be avoided."

Using a luminescent dye, researchers measured cell viability by quantifying adenosine triphosphate after each exposure period in each storage medium. To measure proliferative capacity, they used the prestoblue assay after 12 or 24 hours storage in each medium.

Additionally, researchers assessed the morphology of the cells after 12 hours in a storage medium using a live/dead viability/cytotoxicity kit with fluorescence microscopy.

For statistical analysis, researchers used IBM SPSS Statistics Version 23. "A two-way ANOVA was used to analyze the effects of different media and storage time on cell viability; Fisher's Least Significant Difference (LSD) was used for post hoc analysis. P values less than 0.05 were considered significant."

Researchers found that at up to 6 hours each commercial storage medium supported HPDLF cell viability with no significant difference. By 12 hours, one of the commercial storage media was still effective in maintaining HPDLF cell viability, but by 24 hours its effectiveness was similar to water. Ultimately, “a significant difference in viability of the cells existed among tested media when compared over all time points (P < .05). … The cells treated with water had the lowest rate of viability overall. Each of these differences was statistically significant (P < .05),” the researchers wrote.

In maintaining HPDLF cell proliferative capacity, one of the 3 commercial storage media performed significantly higher than the negative control. "In addition to the existence of vital PDL cells, maintaining proliferative capacity is decisive for periodontal healing following replantation," the researchers wrote.

The researchers concluded that only one storage medium supported the proliferative capacity of HPDLFs after 24 hours.

Read the full article here.


Get ready for the next event

Essential Dental Seminars logo

As a leader in endodontic workshops, Essential Dental Seminars has expanded its course offerings to include a course that will be a benefit to every dentist. Presented by Dr. Chris Salierno, chief editor of Dental Economics, this course focuses on the business side of your dental practice. For complete course details and additional listings visit:

Register now for AAE fall meeting

Image of American Association of Endodontists’ Insight Track logo

Registration is open for the American Association of Endodontists’ fall meeting, Insight Track: Diagnosis and Decision Making. Taking place November 9-11, 2017, at the Wild Dunes Resort in Isle of Palms, South Carolina, the Insight Track will help clinicians hone their skills and uncover new tools designed to help them adapt in the changing dental health care landscape. The 3-day meeting includes an intensive exploration of new diagnostic technologies, pain management methods, treatment techniques, material variations, and prognosis statistics. Topics include CBCT, cracked teeth, implants vs. endodontic treatment, pain management, and pharmacology. Visit for more information and to register.

Image of Tango-Endo 2-step instrumentation system

Endodontic instrumentation system receives top product award.
Tango-Endo, the 2-step instrumentation system by Essential Dental System, has recently received multiple dentistry awards. The latest is Dentistry Today’s 2017 Top Product Award. For detail, product information and a free in-office demo click here.


JADA+ Specialty Scans and JADA+ Scans

JADA+ Specialty Scans and JADA+ Scans are quarterly newsletters updating dentists on the latest research in selected specialties and disciplines in dentistry. ADA Publishing and the consulting editors from the represented specialties and disciplines aggregate and summarize research from previously published materials, each item attributed to its publication of origin. JADA+ Scan specialties and disciplines include endodontics, oral pathology, orthodontics, pediatric dentistry, periodontics, prosthodontics, radiology, cosmetic/esthetic and osseointegration. The ADA has engaged the specialty organizations in these areas as well as its own Science Institute and Division of Legal Affairs to assist with these newsletters. View past issues here.

Editorial and Advertising Policies

Any statements of opinion or fact are those of the authors and do not necessarily reflect the views of the American Dental Association. Neither the ADA nor any of its subsidiaries have any financial interest in any products mentioned in this publication. Any reference to a product or service, whether in advertisements or otherwise, is not intended as an endorsement or as approval by the ADA or any of its affiliated organizations unless accompanied by an authorized statement that such approval or endorsement has been granted.

All matters pertaining to advertising should be addressed to the advertising sales manager, Sales and Marketing Department, American Dental Association, Publishing Division, 211 E. Chicago Ave., Chicago, Ill 60611, 1-312-440-2740, fax 1-312-440-2550. All advertising appearing in ADA publications must comply with official published standards of the American Dental Association, a copy of which is available on request.