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JADA Specialty Scan - Endodontics
Endodontics - A Quarterly Newsletter on Dental SpecialtiesJADA Specialty Scan

Persistent pain after RCT and TMD

The cause of discomfort in the majority of patients reporting tooth pain six months after root canal therapy (RCT) can be attributed to nonodontogenic causes, most frequently temporomandibular joint disorder (TMD), a study published in the April 2015, issue of the Journal of Endodontics reported. The findings are important to both clinicians and patients because patients experiencing such pain are not likely to benefit from endodontic retreatment or tooth extraction.

The cause of persistent pain after RCT is broadly defined as odontogenic (rising from the tissues of the teeth) or nonodontogenic. Scientists found that although odontogenic sources are well described in the literature, information about nonodontogenic sources primarily reside in cross-sectional case reports and case series. “Although these reports provide information about the clinical features necessary to diagnose patients, they do not further our understanding of the prevalence of these conditions in dental clinic populations,” authors said. 

Their research and subjects originated in a large-scale prospective longitudinal cohort study following patients who received RCT from dentists in the National Dental Practice-Based Research Network in five geographic regions. Scientists followed patients aged 19-70 who were available through follow-up six months after RCT and had met study criteria for persistent pain. Patients within the Midwest region were selected for this nested study because of their ability to commute to evaluations at one location, the University of Minnesota School of Dentistry.

Patients and dentists completed questionnaires before and immediately after treatment visits. Patients also completed questionnaires at one, three and six months after RCT. An endodontist and an orofacial pain practitioner independently performed clinical evaluations, which included periapical and cone beam computed tomography (CBCT) to determine pain diagnosis. Final diagnoses were derived by the two practitioners using all available data.

Results showed that of the 390 Midwesterners enrolled, 354 returned data at six months. Of those 354 patients, 38 (11 percent) met the study criteria for pain at six months, which was slightly higher than the 10 percent observed over the entire (parent) study population. One half of these patients (19) agreed to be clinically evaluated.

The clinical evaluation revealed that seven patients (37 percent) had exclusively odontogenic reasons for their pain symptoms and eight patients (42 percent) had exclusively nonodontogenic reasons. Two patients (11 percent) had mixed odontogenic and nonodontogenic reasons. “The presence of a mixed odontogenic/nonodontogenic pain group is important because it requires the clinician to diagnose both etiologies for the report of pain, which can be challenging,” authors said.

Two others (11 percent) were pain free by the time of the six-month evaluation.

Among the nonodontogenic pain group, seven patients were diagnosed with TMD and one was diagnosed with persistent dentoalveolar pain disorder.

While the majority of patients with an odontogenic reason for their persistent pain showed significant findings on their periapical films and cone beam computed tomography scans, patients with nonodontogenic reasons for their pain had fewer findings on their periapical films and CBCT scans.

Scientists noted a difference in patients’ report of pain localization by classification, with 83 percent of patients with an odontogenic diagnosis describing their pain as well localized versus only 25 percent of patients with a nonodontogenic diagnosis. Authors found it surprising that 75 percent of patients with nonodontogenic reasons for pain, which was mainly TMD, reported no previous history of TMD diagnoses. They called for research to investigate how TMD and odontogenic pain are related and also said among conclusions that the findings suggest that patients experiencing persistent pain after RCT should be evaluated for TMD.

Read the original article.


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

Apical microsurgery and healing

What factors should clinicians consider when predicting healing outcomes after apical microsurgery (AMS)?

Scientists at Ege University, in Turkey, evaluated the influence of various predictors on the two- to six-year outcomes of AMS and compared their findings with other AMS investigations. They published the research in the April 10, 2015, online edition of the International Endodontic Journal.

Largely replacing traditional root-end surgery (TRS) since 1997, AMS differs significantly from TRS in the methods used to achieve periapical healing, including the root-end filling material (amalgam versus biocompatible cements such as mineral trioxide aggregate (MTA). Typically, clinical studies on periapical surgery have evaluated outcomes with respect to the root-end filling material.

Authors report that few recent studies have reported the long-term success of AMS and, although the assessment of significant outcome predictors requires long-term observation, long-term results have been reported only in two previous studies.

Scientists studied data of 90 patients from June 2007 through December 2013. Patients studied had asymptomatic periradicular periodontitis of strictly endodontic origin that failed after either nonsurgical or surgical treatment, with only one affected tooth per patient. Some 64 maxillary incisors, six maxillary canines and 20 mandibular incisors met the study’s inclusion criteria. Each patient had undergone clinical and radiologic examination, was diagnosed and had been assigned a treatment plan.

Scientists evaluated predictors prior to AMS, including:

  • Gender.
  • Age.
  • Tooth location and type.
  • Quality of the root canal filling.
  • Presence or absence of a post.
  • Previous endodontic treatment or retreatment.
  • Previous nonsurgical or surgical endodontic treatment.
  • Histopathology of periapical lesions.
  • Antibiotic therapy.
  • Postoperative healing course.

Results showed that none of the investigated predictors had a significant influence on the outcome of AMS. Clinical and radiographic assessment revealed that 80 percent of teeth were healed, 14.4 percent were not healed and 5.6 percent were deemed uncertain.

In discussion, authors noted various results of their study compared with that of other studies in the dental literature. Among them, patients that experienced an uneventful healing phase (82 of 90 cases) also had a better success rate (81.7 percent) compared with patients with postoperative complications (8 of 90 cases), or 62.5 percent. However, the difference was not statistically significant. In cases in which postoperative tissue swelling was accompanied by pain, antibiotics were prescribed. However, there was no significant influence of postoperative medication on the treatment outcome.

In this study, most of the teeth had a large persistent periapical lesion with a diameter ranging from 6 to 20 millimeters (72.2 percent). The size of the lesion had marginally negative influences on the outcome, but again, the differences were not statistically significant.

“During surgery, curettage of the pathological lesion may be incomplete especially in large lesions,” authors said in discussion. “Therefore, even though the inflammatory stimuli are eliminated, the residual tissue may act as a nidus for persistent infection, which would be difficult to overcome by the individual’s immunological capacity.  Thus, the patient’s immunological competence should probably be considered as a factor affecting the outcome of treatment.”

Read the original article.


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New research on commonly used calcium hydroxide formulations

Seeking to identify the effects of three commonly used formulations of calcium hydroxide on the fracture resistance of dentin, scientists at Loma Linda School of Dentistry in California, conducted a study and published their findings in the April 19, 2015, online edition of Dental Traumatology.

Calcium hydroxide, Ca(OH)2, is frequently used by general practitioners as a deep cavity liner because of its bactericidal and healing properties. For these same reasons, endodontists find it useful as an intracanal medicament. The literature shows Ca(OH)2 is commonly used within the root canal system for varying lengths of time—from five to 20 months as an apical barrier and as an inter-appointment medication for as little as a week.

Although the body of research finding that Ca(OH)2 can negatively affect dentinal strength over time has accumulated since 1988, authors found considerable differences in studies’ methods and materials used to test weakening. “The effect on fracture resistance of dentin depending on concentration percentage over time has not been clearly identified in the literature,” authors reported.

To explore, scientists tested three commonly used formulations of varying concentrations of Ca(OH)2 by filling 240 deciduous lamb incisors with one of the three formulations (75 roots for each of the three groups) or a negative saline control (five roots to each control group). They tested fracture resistance for each of the groups at one, three and six months.  

Results showed no significant differences in fracture resistance among any of the experimental groups at any of the time points and no significant differences between any of the experimental groups and negative control groups.

“The cumulative data support that the fracture resistance of dentin is not affected by the concentrations of Ca(OH)2 within these formulations over time,” authors said.

In discussion they considered that the formulations used in their study may be the most influential cause for their results compared to previous studies showing detrimental effect on fracture resistance when Ca(OH)2 is used for an extended period of time.

“The commercial varieties examined have different properties than pure Ca(OH)2 mixed with saline,” authors said. “The mere decrease in available Ca(OH)2 could have been sufficient to lessen the weakening effect on fracture resistance. It is also possible that the additional ingredients of each formulation create a buffering effect on the damage created by the free hydroxyl ions.”

They said that further investigations may shed light on either positive or negative effects of added ingredients (iodoform, cellulose/water gel, barium sulfate). “Additional research to examine effects caused by supplemental ingredients in common commercial dressings is encouraged.”

Read the original article.

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Read more.

AAE introduces new endodontic surgery video

The American Association of Endodontists released a new patient-focused video on endodontic surgery that illustrates the most common form of surgery—apicoectomy—with 3-dimensional animation and easy-to-understand narration.

The video is part of the AAE’s patient education series that also includes videos on root canal treatment, endodontic retreatment, cracked teeth and root canal safety. View the entire video series on the AAE’s YouTube Channel.


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What is Specialty Scan?

This is one in a series of quarterly newsletters updating dentists on selected specialties in dentistry. Information presented is aggregated and summarized from previously published materials, each item attributed to its publication of origin. This issue of JADA Specialty Scan focuses on endodontics, the second in the series on this topic for 2015. Other specialty scan issues are devoted to oral and maxillofacial pathology, oral and maxillofacial radiology, orthodontics, pediatric dentistry, periodontics and prosthodontics. 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. We welcome your feedback on this and all specialty scan issues.

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