Anesthetizing mandibular molars

Pain Control Anesthetizing mandibular molars Background.—Anesthetizing an acutely inflamed mandibular molar (AIMM) is a challenging undertaking. Conventional local anesthetic techniques produce unpredictable results and can have success rates as low as 20% to 50%. A review of the literature and clinical experiences was done to produce a staged approach for obtaining clinically acceptable pulpal anesthesia in the AIMM. Steps in Achieving Anesthesia.—An inferior alveolar nerve block (IANB) is first administered to provide sufficient anesthesia. This approach anesthetizes tissues that receive sensory innervation from the IAN. It is important to continue injecting on withdrawal for lingual block. The best solution is lidocaine 2% with a vasoconstrictor. A total of 1.8 ml is inserted over 60 seconds. If the soft tissues are not sufficiently anesthetized, IANB is repeated. Once the IANB is completed, a long buccal infiltration (LBI) is performed to supplement the anesthesia and improve success rates from 20% to 50% to 60% to 70%. This quick, simple technique anesthetizes tissues that receive sensory innervation from the long buccal branch of the mandibular division of the trigeminal nerve. From 1 to 1.8 ml of articaine 4% anesthetic with a vasoconstrictor is deposited over the course of 10 to 20 seconds, then the pulp and neighboring teeth are tested objectively. LBI is repeated if soft tissue anesthesia is insufficient. If the symptoms persist despite the soft tissue numbness, an intraligamentary injection (ILI) is done. If the LBI failed and no intra-osseous injection (IOI) kit available, ILI is a simple method using a small volume of anesthetic to produce rapid single-tooth anesthesia. Patients should be advised of the postoperative discomfort associated with the technique. The appropriate solution is adrenaline plus anesthetic (if not medically contraindicated). Over 20 seconds, 0.2 ml is deposited under back pressure mesially, distally, and into the buccal furcation. Computer-controlled delivery systems (CCDS) may be used to deliver the ILI but are not essential. The pulp and neighboring teeth are tested. If the initial administration fails, the ILI can be repeated. If symptoms persist despite repeated ILIs, an IOI can be done. The IOI is technically more difficult but produces more predictable results for anesthetizing the AIMM, with success rates between 80% and 100%. A specialized delivery system will perforate the cortical plate adjacent to the tooth, so the

anesthetic can be delivered directly into cancellous bone, then will rapidly bathe the periradicular region to produce profound pulpal anesthesia. For the IOI, 2% lidocaine with a vasoconstrictor is used except for patients with cardiovascular diseases, who should be given mepivocaine 3% plain; bupivacaine is avoided for these patients. The 0.9 to 1.8 ml of anesthetic is deposited over 3 to 4 minutes, taking care to avoid backflow into the oral cavity. Although Stabilident and X-tip have similar efficacy, X-tip is better at localizing the perforation site. The pulp and nearby teeth are tested objectively. If the initial administration is ineffective or the anesthesia wears off, IOI can be repeated. If symptoms persist, an intra-pulpal injection (IPI) may be required. IPI is indicated for patients who do not achieve adequate pulpal anesthesia even after LBI, ILI, and IOI. The anesthetic is deposited via conventional methods into a small opening into the pulp chamber, termed the pulp horn. A high level of back pressure must be maintained to induce immediate onset. Patients should be advised of the brief moderate to severe pain that accompanies administration. Alternative Approach.—On occasion, the conventional technique does not result in the anesthesia spreading to the entire pulp. In these cases, although the coronal pulp tissue can be removed comfortably, extirpation of the radicular pulp can be painful. For these patients a variation of the conventional IPI is done to counteract the pain. First, the coronal tooth structure is stabilized, then the pulp is accessed and hemostasis achieved. The solution is deposited and a bung is created. The bung should remain in the pulp chamber for 60 seconds, which will produce the needed pressure to force the solution down into the root canal system. As a result, immediate and profound anesthesia, especially in the radicular pulp, is created. If the anesthesia wears off during treatment, the bung can be replaced in the pulp chamber. There is no need to remove the rubber dam. Discussion.—The strategy proposed is designed to help practitioners achieve more predictable results when seeking to anesthetize AIMM.

Clinical Significance.—A systematic approach for anesthetizing acutely inflamed mandibular molars allows practitioners to

Volume 61



Issue 4



2016

203

achieve more predictable results. If these techniques work for AIMM, the same principles can also be used to help anesthetize other teeth with an acutely inflamed pulp.

Virdee SS, Bhakta S, Seymour D: Effective anaesthesia of the acutely inflamed pulp: Part 2. Clinical strategies. Br Dent J 219:439-445, 2015 Reprints available from SS Virdee, Restorative Dental Core Trainee; e-mail: [email protected]

Opioid pain relievers Background.—Opioid pain relievers (OPRs) are among the most frequently prescribed medications in the United States. Dentists typically prescribe them for short-term pain control and use lower doses than other practitioners, but it’s important to remember the unintended consequences that can attend their use. This includes dependency on the drugs and diversion of unused pills to persons who may abuse them or sell them to drug abusers. Understanding the usefulness of OPRs in dental practice, the agents used, and the potential for abuse can help dentists prescribe the correct agents and limit the chance for misuse. Dental Opioid Use.—A significant portion of the 1 to 1.5 billion doses of opioids prescribed by dentists are for patients having third-molar extraction surgery, whose average age is 20 years. These agents (e.g., codeine, oxycodone, hydrocodone, meperidine, etc.) are indicated for acute pain management but can also be used as antitussives, antidiarrheal agents, or analgesics for chronic pain. Their mechanism of action is to bind to opiate receptors in the brain, spinal cord, and gastrointestinal tract, producing an attenuation of pain perception. Used with nonopioid analgesics, pain production is blocked by the combination of prostaglandin inhibition and opiate receptor activity. Side effects to the use of OPRs include nausea, constipation, and drowsiness. When these agents are given at high doses, patients can experience respiratory and central nervous system (CNS) depression. In ambulatory patients, the side effects can be exaggerated, producing serious problems that can outweigh their usefulness as pain control medications. Clinicians must be aware of the contraindications associated with opioids. These include allergic responses, impaired respiratory function, paralytic ileus, and a history of renal or hepatic disease. Using opioids with drugs such as monoamine oxidase inhibitors or CNS depressants can produce life-threatening effects. Very old and very young patients and those actively involved in

204

Dental Abstracts

dependency or addiction or drug dealing should not be given opioids. Agents Used in Dentistry.—Dentists can choose opioids combined with acetaminophen (APAP) or nonsteroidal anti-inflammatory drugs (NSAIDs) to achieve postoperative pain control, thus avoiding the use of opioids alone. NSAIDs have been shown to offer better pain control with fewer side effects and can reduce swelling with administration lasting 2 to 3 days. They can also be given preventively to block the onset or lessen the severity of pain postoperatively. The NSAID used in these cases delays the onset of pain by nearly 2 hours. Used both before and after a dental procedure, NSAIDs can achieve better pain relief than APAP alone or combined with oxycodone. This approach gives the drugs a chance to be properly absorbed so they can reach peak effectiveness by the time the anesthetic wears off and allows the dentist to more readily comply with Food and Drug Administration (FDA) recommendations regarding the use of doses that achieve maximum benefit with minimal risk for adverse events. Bupivacaine can also be used as a long-acting surgical anesthetic, giving patients the opportunity to adjust to the pain more gradually. Most dentists use this agent for third-molar procedures. The use of 0.5% bupivacaine with 1:200,000 epinephrine given immediately after surgery achieves diminished pain levels compared to the use of placebo and lidocaine alone up to 4 hours postoperatively and at 48 hours after surgery. Dentists prescribe opioids for those patients who suffer acute pain related to severe pulpitis or abscesses. However, NSAIDs and APAP are often more effective, so dentists should consider their use. Combination pain therapy with NSAIDS plus APAP offers a more favorable side effect profile than agents containing opioids for postoperative pain management. Opioid Abuse.—Opioids, CNS depressants, and stimulants are the most commonly misused or abused drugs