Exciting Scientific Advances Are Moving Endodontic Care, Pain Management Forward

These two interrelated disciplines are among the most exciting in dentistry for both clinicians and researchers. The science and practice of clinical endodontics progresses quickly. Resultantly, virtually every clinician providing endodontic care gets to experience real changes in methodologies and technologies during their career. These advances have enhanced outcomes in both nonsurgical and surgical endodontics. Similarly, seismic shifts in pain management continue to occur, and significant advances in the understanding of pain physiology, as well as drugs and devices for the prevention and treatment of pain, have greatly improved patient care.

In endodontics, the past decade has seen major advancements related to the incorporation of 3-dimensional imaging modalities and the widespread adoption of tricalcium silicate cements, or bioceramics, into clinical practice. Additionally, investigations into irrigation have also led to significant changes within the field. CBCT imaging has been broadly adopted in the practice of endodontics because of its ability to improve diagnostic accuracy and enhance the delivery of nonsurgical and surgical endodontic care.¹ Its utility in assessing resorptive dental diseases, fractures, traumatic dental injuries, and recurrent endodontic pathology cannot be underscored enough.¹ CBCT images can be applied to both nonsurgical endodontics with the creation of 3-dimensional guides utilized for endodontic access, or surgical endodontics with guides for flap design and apical resection.^2,3 The technology is widely impactful and represents a paradigm shift in the way clinical endodontics is practiced at the specialty level.

Similarly, bioceramics represent a paradigm shift in endodontics. They possess broad applications given their exceptional biocompatibility in the presence of periapical tissues and regenerative capacity to these tissues.⁴ They are the mainstay materials for perforation repair due to their predictability in sealing these defects and have become the preferred apical retrofilling material in endodontic microsurgery.⁴ Bioceramics are associated with more predictable outcomes than calcium hydroxide materials in apexification procedures, where they additionally allow for single-visit procedures, increasing efficiency, patient compliance, and long-term success.⁵ Similarly, they represent the gold standard materials when restorative materials must be placed in contact with the pulp tissues, including direct pulp capping or pulpotomy procedures and regenerative endodontic procedures.^4,6 The predictability of pulp capping and pulpotomy procedures has improved to such a degree as a result of the use of these materials that vital pulp therapy now represents the treatment of choice for carious pulp exposures.⁶ Bioceramics have more recently been incorporated into endodontic sealers, where they show promise because of their favorable biologic sealing abilities.⁷

Endodontic irrigation has long been an area of active research, wherein investigators compare the efficacy of novel and mainstay solutions and techniques. Irrigation is essential in endodontics as instrumentation alone leaves 30% of canal walls untouched.⁸ Moreover, the use of instrumentation creates a smear layer of organic and inorganic debris that may impact sealing of the canal space, prior to obturation. Although novel solutions have been investigated, sodium hypochlorite remains the most effective irrigation agent. Sodium hypochlorite is antimicrobial and dissolves soft tissue but is unable to dissolve the hard-tissue component of the smear layer.⁸ Additional solutions prove advantageous in endodontics, especially ethylenediaminetetraacetic acid (EDTA) for its calcium chelating abilities, allowing it to eradicate hard-tissue debris.⁹ In general, sodium hypochlorite should be utilized during the majority of the endodontic procedure, with EDTA employed as a final rinsing agent to remove the smear layer.

Beyond irrigating solutions, much research and development has occurred in recent years regarding techniques and technologies to enhance irrigants' cleaning abilities. It is now well accepted that some degree of "active" irrigation, by way of sonic or ultrasonic instruments placed within the canal space, enhances the mainstay irrigant solutions' abilities to clean the canal.¹⁰ Newer technologies like minimally invasive root canal systems and lasers are under study (eg, GentleWave^® Procedure, Sonendo; EdgePRO^™, EdgeEndo), however evidence does not yet support their routine adoption.^11-13

Just as endodontics has seen marked shifts, so too has the interrelated discipline of pain management. Pain management is an essential component in the provision of endodontic care in the preoperative, intraoperative, and postoperative phases. Generally speaking, preoperative pain, particularly that secondary to symptomatic irreversible pulpitis or acute apical abscess, is more severe than postoperative pain. That said, the pain of a postoperative flare-up, or in patients with increased levels of preoperative pain, can be quite severe. Either is best managed with combination therapy using nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen.¹⁴ Ibuprofen has traditionally been the recommended NSAID utilized in endodontics given its broad availability, dosing and intervals similar to acetaminophen, and low side-effect profile; however, alternative NSAIDs have shown efficacy. Dosages may be adjusted to best manage the level of pain reported.

Except in cases of allergies that may limit the use of the above medications, opioid-based therapies are no longer advised in the management of pain of endodontic origin. Not only are these therapies associated with greater side effects and the potential for dependence and abuse, but they are less effective than the combination of NSAIDs and acetaminophen.¹⁵ That said, the pharmaceutical industry's reckoning with opioid drugs may pressure further research into non-opioid pain alternatives. Already, research is active in the area of cannabinoids and other novel targets to manage pain that will undoubtedly impact dentistry as they come to fruition.¹⁶

Although the use of local anesthetics in dentistry has been traditionally relegated to the management of intraoperative pain, their use too may be considered to manage both preoperative and postoperative pain. In the medical literature, long-acting analgesics like bupivacaine, administered presurgically, have shown efficacy in reducing levels of postoperative pain, which is likely due to their abilities to reduce afferent impulses creating centralized pain.¹⁷ Clinically, this means that bupivacaine may be considered for procedural local anesthesia with effects to reduce the levels of postoperative pain.

Local anesthesia is a field that has seen interest in product and technology research and development aimed at improving delivery and efficacy. Nonetheless, no means yet tested has shown greater efficacy in achieving pulpal anesthesia of the mandibular molar with symptomatic irreversible pulpitis than traditional anesthetics delivered by traditional means. The most efficacious methodology involves the combination of 2% lidocaine with epinephrine administered via inferior alveolar nerve block, supplemented with 4% articaine with epinephrine delivered via local infiltration on the buccal.¹⁸ Adequate doses (two cartridges for the block, one cartridge for the infiltration) and sufficient time (up to 25 minutes) represent key components in the achievement of pulpal anesthesia.^19,20 Adjunctive methodologies, including intraligamentary or intraosseous anesthesia,¹⁸ premedication with NSAIDs and acetaminophen, or perioperative use of nitrous oxide, may also enhance the achievement of pulpal anesthesia in the especially refractory tooth.^19,21,22 Beyond these, sedation, namely via intravenous administration of anesthesia medications, remains an option if all other methodologies are insufficient for anesthesia.

Endodontics and pain management are separate but interrelated disciplines. Enhancements in imaging modalities, biomaterials, and methodologies have made the delivery of endodontic treatment more predictable. Moreover, research in pain management has made both the provision of endodontic treatment and its postoperative period more comfortable. The continued rapid evolution in both disciplines will no doubt continue to benefit patients and enhance provider excitement in these remarkable fields.

Rebekah Lucier Pryles, DMD, Certificate in Endodontics
Assistant Clinical Professor, Department of Endodontics, Tufts University School of Dental Medicine, Boston, Massachusetts; Clinical Instructor, Department of Restorative Dentistry and Biomaterials Science, Harvard School of Dental Medicine, Boston, Massachusetts; Co-founder, Pulp Nonfiction Endodontics; Private Practice limited to Endodontics, White River Junction, Vermont

Brooke Blicher, DMD, Certificate in Endodontics
Assistant Clinical Professor, Department of Endodontics, Tufts University School of Dental Medicine, Boston, Massachusetts; Clinical Instructor, Department of Restorative Dentistry and Biomaterials Science,
Harvard School of Dental Medicine, Boston, Massachusetts; Co-founder, Pulp Nonfiction Endodontics; Private Practice limited to Endodontics, White River Junction, Vermont