A prospective study on MTA outcomes
Scientists in Amsterdam investigated treatment outcomes of deep caries lesions treated with mineral trioxide aggregate (MTA) and published their findings in the July 2015 issue of the Journal of Endodontics. They assessed permanent teeth after complete excavation of caries with a two-visit treatment protocol. Pulp sensibility, tooth discoloration and caries were addressed.
Less studied than calcium hydroxide for direct pulp capping, advantages found in recent investigations of MTA were reduced inflammation, hyperemia and necrosis levels. In addition, MTA was shown to create thicker dentin bridges, minimal tunnel defects and faster apposition of dentin. Resisting bacterial leakage, MTA may provide protection for the pulp, allowing repair and continued pulp vitality. Disadvantages found were discoloration, difficult manipulation, slow setting time and material cost.
To assess outcomes with a prospective study design, the scientists selected 59 patients consecutively treated at a general private practice between 2008 and 2011. Each was treated after the diagnosis of extensive primary or secondary deep caries when pulp exposure was expected after clinical or radiographic evaluation. Ultimately, 64 permanent teeth were treated: five incisors, 17 premolars, and 42 molars; 38 were maxillary and 26 were mandibular. The patient sample consisted of 32 females and 27 males with a mean age of 36.1.
One practitioner performed all procedures (except two definitive bonded restorations performed by another practitioner within the same practice) under rubber dam and local anesthesia. At a second appointment, four to 12 weeks later, scientists conducted positive sensibility testing and confirmed the MTA setting. The practitioner placed bonded composite restorations afterward.
Patients were recalled yearly for clinical tests and periapical radiographs. Success was defined as a positive cold test, no pain on percussion and no widening of the periodontal ligament on the periapical radiograph.
Results showed that 77.9 percent of patients (46 teeth) were recalled after 3.6 years. The overall success rate was 91.3 percent. The rate of immediate failure (between first and second appointments) and late failure (follow-up appointment > 3 years) were both 3.1 percent. Bleeding was detected in both of the immediate failure teeth and not detected in both of the late failure teeth. Recurrent caries occurred in one late failure case.
Pulp bleeding, caries location and initial versus secondary caries did not influence the outcome. The success rate in initial caries was 94.7 percent and 88.9 percent in secondary caries.
Patient age influenced outcomes. The success rate in patients younger than 40 years old was 100 percent and 80 percent in patients older than 40. No significant differences were found between pulp bleeding and non-bleeding groups and the overall probability of pulp survival at four years was 87.3 percent.
In discussion authors said the success rate of 91.3 percent in the study compares with the results of previous studies. They surmised that the lower overall probability of pulp survival at four years in their study (87.3 percent), compared to 94.8 percent in a previous study could be explained: teeth in the former study exhibited initial deep caries and no prior restorations, whereas in the current study, initial and secondary caries were treated. Also, the age group of subjects in the former study (seven to 48 years) differed from that in the current study (eight to 68 years).
“Our study should be seen as a pilot experiment to justify prospective studies with larger sample sizes, aiding in the creation of guidelines for the use of MTA for pulp capping,” authors suggested.
They concluded that direct pulp capping with MTA after exposure during deep caries removal could maintain pulp vitality in permanent teeth when a two-visit treatment protocol is observed.
Read the original article.
Consulting Editor: Dr. Susan Wood
Diplomate, American Board of Endodontics
Direct pulp capping materials
Although mineral trioxide aggregate (MTA) has shown superior biocompatibility and sealing ability, limitations regarding its use as a capping material include poor manipulability and long setting times. Such limitations restrict certain applications, such as the immediate sealing of the cavity with a bonded restoration in a single visit.
According to the dental literature, the time span before the placement of a permanent restoration after direct pulp capping (DPC) is a prognostic factor influencing outcome. When the time span increases to longer than two days, the success rate of DPC significantly decreases.
A recently introduced fast-setting pozzolan-based MTA is gaining attention as an alternative capping material, particularly for its high manipulability and fast setting properties. Scientists publishing in the August 2015 issue of the Journal of Endodontics conducted a previous study that confirmed clinical outcomes of the material, Endocem, for up to three months. Considering that the cumulative success of DPC could alter over time, the scientists determined a three-month follow-up period insufficient to guarantee the long-term prognosis of capping materials. To secure more reliable clinical evidence, particularly long-term results of at least one year, they conducted a study to evaluate the one-year cumulative successes of both ProRoot MTA and Endocem and compared them with the three month outcomes in a prospective, randomized controlled trial.
To investigate, scientists ultimately studied 35 patients (46 teeth) that met the inclusion criteria from among patients who attended the Department of Conservative Dentistry, Yonsei University Dental Hospital, Seoul, Korea, from January to May 2013. Teeth were randomly assigned to ProRoot or Endocem groups (23 teeth per group). Scientists performed DPC and conducted clinical and radiographic examinations at one, two, four and 12 weeks, six months and one year after the treatments. Periapical radiographs were blindly evaluated by two independent examiners who were not involved in the clinical procedure.
Researchers classified cases as successful when the tooth exhibited a positive response to the pulp sensibility test without any evidence of irreversible pulpitis or pulp necrosis in either the clinical or radiographic examinations. Negative response to the pulp sensibility test, spontaneous pain that was not resolved with analgesics or well-defined apical radiolucency on periapical radiographs were categorized as treatment failures.
Results showed no significant differences between the cumulative successes for up to one year of the two materials. However, cavity type (class I, II, III vs. class V) was found significant. Some two-thirds of the failed cases (four of six) had class V cavities that were caused by root caries.
In addition to the study identifying no significant differences in the one-year cumulative successes of the two DPC materials, authors also concluded that the cumulative success of DPC might be reduced in teeth restored with class V cavities and that a follow-up period of at least one year is required to assess the prognosis of MTA pulp capping.
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Apexification, intracanal medication and fracture resistance
Research in the June 2015 issue of Dental Traumatology showed that more than 15 days' use of calcium hydroxide dressing reduced dentin fracture resistance.
“The shorter period of intracanal medication dressing required in revascularization therapy has demonstrated to be another advantage of this treatment when compared to apexification,” authors said. Scientists in Brazil evaluated the action of irrigant solutions and the long-term use of calcium hydroxide on the fracture resistance of weakened bovine teeth.
A widely used treatment for necrotic cases of immature teeth, apexification therapy entails root canal treatment with periodic changes of intracanal medication until an apical barrier is formed. Compared to revascularization, apexification requires a longer duration of intracanal calcium hydroxide placement and irrigant solution contact with dentinal walls. Additionally, some research has shown that irrigant solutions used for bacteria elimination within the apexification protocol may interfere with the mechanical properties of dentinal walls.
Endodontic treatment may increase weakness. Previous research has reported that 60 percent of all endodontically treated immature teeth have suffered fractures due to minor impacts.
The scientists found few studies evaluating the influence of irrigant solutions and intracanal medications on fracture resistance in such weakened root walls. To investigate, they evaluated the action of three commonly used irrigant solutions — physiological solution (group SS), 1 percent sodium hypochlorite (group NaOCI) and 2 percent chlorhexidine gel (group CHX) — as well as the long-term use of calcium hydroxide on the fracture resistance of weakened bovine teeth.
Teeth were randomly divided into three experimental groups according to the tested irrigant solution and two control groups. After instrumentation, root canals were dressed with calcium hydroxide and evaluated throughout different periods (15, 60, 90, 180 and 360 days), with changes of medication every 30 days. Compressive loading was applied until fracture occurred and the maximum force required to fracture each specimen was recorded and analyzed.
Among results, reduction in fracture resistance was associated with longer periods of intracanal medication maintenance. At 60, 90, 180 and 360 days, a significant decrease in fracture resistance was observed for almost all analyzed groups when compared to groups medicated for 15 days and controls. Also among results, in longer periods of exposure to intracanal medication (180 and 360 days), root canals irrigated with NaOCI or CHX showed significantly lower fracture resistance than SS.
“Within the limitations of this in vitro study, it may be concluded that the use of NaOCI or CHX as irrigant solutions as well as calcium hydroxide as an intracanal medication for long-term periods may reduce the fracture resistance of weakened tooth roots,” authors reported.
In conclusion they said that apexification with periodic changes of calcium hydroxide medicament leads to weakness of the teeth independent of the irrigation solution used.
Read the original article.
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Debating hot topics in endodontics
The American Association of Endodontists is hosting The Insight Track: Contemporary Dilemmas in Endodontics Oct. 22-24 in Key Largo, Fla. Education sessions will be presented in a point-counterpoint format, giving attendees the opportunity to hear both sides of the issue as they are debated by some of the top speakers in the field.
Topics include minimally invasive endodontics versus conventional endodontics, retreatment versus surgery, and one-visit versus two-visit endodontics. For more information and to register, visit the AAE website.
CBCT in Endodontics
In response to new developments and research indicating the effectiveness of 3-D imaging for endodontic diagnosis and treatment, the American Association of Endodontists and the American Academy of Oral and Maxillofacial Radiology have issued a revised position statement on the use of cone beam-computed tomography in endodontics. The statement emphasizes that CBCT should not be used routinely for endodontic diagnosis or screening purposes in the absence of clinical signs and symptoms, and provides 11 specific recommendations and supporting evidence for when CBCT should be considered the imaging modality of choice. The statement is consistent with principles of ALARA — keeping patient radiation doses “as low as reasonably achievable,” and notes that the patient’s history and clinical examination must justify the use of CBCT by demonstrating that the benefits to the patient outweigh the potential risks. The position statement is available from the AAE.
Endodontic Instrumentation System received multiple awards
Tango-Endo, the new two-step instrumentation system by Essential Dental System, has recently received multiple dentistry awards. These awards include a 2015 Top Product Award and an Editor’s Choice Award. For an updated list of awards and product reviews please click here.
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 third in the series on this topic for 2015. Other specialty scan issues are devoted to oral 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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