"Hot tooth": How to keep cool

More than the fear patients carry for root canal, I think we as dentists have for acute irreversible pulpitis. We have all been there - when the patient is in dire need of an emergency pulpectomy, we are struggling to take him up between our regular appointments, and the anesthesia just won't work.

 Here is how to keep your cool when the tooth has gone "hot":

• Administer the local anesthetic distal to the area of inflammation - supraperiosteal infiltration for maxillary teeth and regional nerve block for mandibular teeth. By injecting distal to the tooth, we are depositing away from the area of inflammation and closer to the nerve trunk. 
• Deposit a greater amount of the anesthetic to provide a greater number of uncharged base molecules. For both maxillary buccal infiltration and mental block, I usually deposit 1.5 ml (recommended is 0.6 ml); for palatal infiltration 0.4 ml (recommended 0.2 ml); and, for inferior alveolar nerve block 2.2 ml (recommended 1.5 ml). For the maxillary molars, deposit 1 ml each over the two buccal roots separately, followed by 0.4 ml of palatal infiltration. Supplement the inferior alveolar nerve block with supraperiosteal infiltration. 
• For maxillary infiltration, I deposit some amount not as supraperiosteal but rather directly over the bone. (Even though there is no recommendation in the literature for the same, what I am aiming for is the effect of an intraosseous injection). This needs to be done very slowly like a palatal injection, allowing time for the anesthetic to diffuse from the area before depositing more. 
• Pulpal anesthesia sets in after soft tissue anesthesia. Therefore, it is a good practice to wait a little more after the subjective signs of anesthesia are realized before initiating the access cavity preparation. 
• Even in the most acute of cases, this protocol allows me to reach till the dental pulp; when now, if still needed, I administer the intrapulpal injection. "If needed" here must not be taken to mean "when the patient complains of pain". The effectiveness of intrapulpal injection lies in pressure, obtained by binding of the needle in the pulp chamber opening. Therefore, one must keep in mind for all cases of acute pulpitis to intentionally check for pain by probing as soon as a dip is made into the pulp chamber. Even mild sensation at this point warrants an intrapulpal injection before the opening is enlarged any further. If binding is not obtained, however, the intrapulpal may still be administered into the canals individually. 
• So, what if the patient still experiences pain when an endodontic instrument is inserted into the root canal?

• Theoretically, the best option here is either a periodontal ligament injection or an intraosseous injection. The documented cardiovascular effects of the intraosseous technique as well as the requirement of additional armamentarium have kept me from using this. I have not found much additional success with the periodontal ligament injection as well. Having been satisfactorily following the protocol I am sharing in this blog for quite a while now, I do not try the periodontal ligament injection anymore. I invite comments from readers experienced in these techniques.
• At this point, one can either repeat the initial injection (infiltration or block for maxillary and block for mandibular); or go with the intraseptal. I use both depending on my clinical judjement. For example, if I had got a positive aspiration in my first inferior alveolar attempt, I will now go for intraseptal to avoid any trismus from repeated injection in the area. If, on the other hand, I am not certain of the subjective signs and symptoms confirming my first injection, I will repeat the first injection. In general, I have found some soreness persists in the area of intraseptal injection after the effect of the anesthetic has worn away and so I use it only as the last resort. 
• As the famous English writer Rudyard Kipling said - "Words are the most powerful drug used by mankind". Keep talking and comforting the patient. Do not ignore his pain, because it is real; but explain the reason why the anesthetic is not working. You may demonstrate the objective signs of the anesthesia to convince the patient that it has been aptly administered. 
• Many dentists prefer to do a partial pulpectomy followed by a formocresol dressing in such cases, to help the patient tide over the acute dental emergency till the next time when the anesthetic is likely to be more effective. I am myself not in much favor of this technique for two reasons - firstly, the pain relief afforded by complete pulpectomy is much superior to only draining the hyperemic pulp, and secondly, formocresol itself has become a subject of scientific debate. However, for those constrained by time due to the unscheduled nature of an emergency dental procedure, Weine recommends performing a formocresol pulpotomy or pulpectomy only for the largest canal - palatal in maxillary molars and distal in mandibular molars. 

Additional reading: Local Anesthesia Strategies for the Patient With a “Hot” Tooth. Nusstein, John M. et al. Dental Clinics , Volume 54 , Issue 2 , 237 - 247