Effect of long acting supplementary local anesthetic on intra and post operative pain in single visit root canal treatment – a randomised control trail

The main rationale of endodontic treatment is the elimination of microorganisms from the infected root canal system by adequate chemo mechanical debridement followed by a three dimensional obturation to achieve hermetic seal that will promote healing in the periradicular region. 1

 There are various factors associated with the occurrence of pain during and post endodontic treatment such as the condition of pulp and periradicular tissues before treatment, immune system mediated phenomena, psychological factors, level of pre-operative pain, periapical tissue pressure etc. Which in confluence with iatrogenic factors such as inadequate root canal instrumentation, extrusion of periapical debris, type of files used in endodontic treatment etc.2

 The pain accompanying endodontic treatment, despite being considered as a poor indicator of pathology and unreliable predictor for the long term success of root canal treatment, needs to be addressed as it could have sustained impact on the patient’s mental perception of root canal treatment.

 Moderate to severe pain during endododntic treatment has ranged from 11% to 35% and even as high as 100% as reported by Abbot et at, 2018 3. Intra-operative pain management in endodontics centers around the achievement of profound local anesthesia. Unfortunately, patients suffering from severe pain of endodontic origin, particularly symptomatic irreversible pulpitis, may experience difficulties in achieving adequate pulpal anesthesia due to issues with techniques, altered ph, or inflammation of the surrounding tissues resulting in pharmacologic failure. Since neither patients nor providers wish to experience breakthrough pain during treatment, and poor past experiences can lead patients to avoid dental care in the future, it is imperative that clinicians provide pain-free care.4

 The time, volume, type of aneasthetic including additives as well as use of supplemental techniques have been employed in controlling peri operative pain. Meechan in 2002, reported that in 80% of patients with irreversible pulpitis, the inferior alveolar block is ineffective. Supplementary injections have proven to aid in achieving substantial anaesthetia. The use of supplementary intra pdl injections resulted in 56–70% having successful anaesthesia. The findings support the pursuit of an effective pain management solution during endodontic treatment.5

 Managing postoperative pain can be one of the more challenging aspects of clinical practice in endodontics and one by which the skill of the clinician is often judged. Good anesthetic technique could eliminate pain during the procedure, but post treatment endodontic pain remains a significant predicament to date.6

 The incidence of this post endodontic pain (PEP), as reported by Sathorn et al, 2008 7, ranges from 3 - 58%. Pak and White et al, 2011 8, concluded that the prevalence of PEP was 40% at 24 hours, whereas it reduced to 11% at 1 week and it was most intense in the first six hours following a gradual decline after a week.

 Several strategies have been adopted to manage the PEP such as premedication using corticosteroids, prophylactic analgesics, occlusal reduction, cryotherapy etc. The effects of these strategies on short as well as long term prevention of pain caused due to endodontic treatment has been studied extensively to determine the most suitable protocol to alleviate pain caused due to endodontic treatment. PEP is usually controlled by the use of mild oral analgesics or nonsteroidal anti-inflammatory drugs. However, nonsteroidal anti-inflammatory drugs may manifest side effects such as gastrointestinal irritation, systemic bleeding tendency, and allergic reactions. These observations justify efforts to find a method of postoperative pain control that does not provoke side effects.

 A considerable number of literatures on intraligamentary anaesthetic technique (ILA) as alternative technique for inferior alveolar nerve block (IANB) were generated over the last years. ILA only requires an injection directly into the periodontal space of the tooth with relatively high pressure. The injected solution spreads to the cancellous bone adjacent to the tooth to be anesthetized. This results in a localized area of anesthetization, without the ill effects of nerve block with soft tissue anesthesia.

 Among the advantages of this technique are the rapid onset of action, a reasonable duration of 30–49 min, for generally employed lignocaine which is in line with standard dental treatment, as well as a low and safe amount of anesthetic solution (about 0.2 ml for each root). It is of high safety in pediatric patients, patients with bleeding disorders as well as in medically compromised patients.9

 Ropivacaine, a long-acting anesthetic, having an onset of action of 2-4 mins, demonstrates a duration of anesthesia ranging between 7 and 11 h for inferior alveolar nerve block and a mean of 9 h for infiltration.10 Hypothetically, this extended duration of anesthesia covers the time of greatest incidence and intensity of postoperative pain following endodontic therapy.

 Most of the evidence based on PubMed search is on the effect of using long‑acting anesthetic on postoperative pain after tooth extraction or periodontal surgery, and this is why such a study is important where the model used is on postoperative pain after RCT. 11,12 Further, there is minimal clinical research into the comparison of incidence of postoperative pain following single visit endodontics between patients anesthetized with lignocaine and ropivacaine with use of supplementary technique of ILA.Hence, an in vivo double‑blind study is proposed to evaluate the effect of supplementary intraligamentary ropivacine on intra as well as post-operative pain in single visit root canal treatment in teeth with symptomatic irreversible pulpitis and to compare the observations of both groups.

 The study hypothesis proposed is as follows:

Null hypothesis (H0) – There is no difference in incidence of postoperative pain in single sitting RCT under lignocaine alone as IANB , LIOGNOCAINE as a supplementary ILA and ropivacaine as a supplementary ILA and used as local anesthetic agent.