Pain Control & Anesthesia in Endodontics PDF

Pain Control & Anesthesia In Endodontics DR. SAAD EL-GENDY B S C , M D, P H D LECTURER OF ENDODONTICS  Outline Classification Clinically available local anesthesia Selection of local anesthesia Effect of systemic disease or systemic condition...

Pain Control & Anesthesia In Endodontics DR. SAAD EL-GENDY B S C , M D, P H D LECTURER OF ENDODONTICS  Outline Classification Clinically available local anesthesia Selection of local anesthesia Effect of systemic disease or systemic condition on local anesthesia Clinical factors inferior alveolar nerve block alternative injection sites Volume and concentration Factors of failure of inferior alveolar nerve block Supplemental anesthesia for vital pulp in the mandible Infiltration IO IP Intraligamental Maxillary anesthesia Anesthesia in Endodontics Oil painting depicting the first use of ether by a dental surgeon in 1846 (Robert Liston)  Local anesthesia Classification Clinically available local anesthesia Selection of local anesthesia Effect of systemic disease or systemic condition on local anesthesia Clinical factors inferior alveolar nerve block alternative injection sites Local anesthesia Clinically available local anesthetics The most common forms of injectable local anesthetics are in the amide class. Depending upon duration local anesthetics can be divided roughly into three types : short duration (30 minutes of pulpal anesthesia), intermediate duration (60 minutes of pulpal anesthesia), and long duration (over 90 minutes of pulpal anesthesia). Local anesthesia Clinically available local anesthetics However, clinically anesthesia does not always follow these guidelines, as it depends on whether the local anesthetic is used as a block or for infiltration For example, bupivacaine is classified as a long-acting agent; when it is used in an inferior alveolar nerve (IAN) block, however, when it is used for infiltration for anterior teeth, it has a shorter duration of anesthetic action than 2% lidocaine with 1:100,000 epinephrine  “Rule of 25” by Finder and Moore; 1 cartridge for every 25 pounds (11.34 Kg) Body Weight Clinically available local anesthetics Cohens 12th edition  Finder and Moore proposed a “rule of 25” as a simple means of remembering maximal local anesthetic dosages: with currently formulated local anesthetic cartridges, it is generally safe to use one cartridge of local anesthetic for every 25 pounds of patient weight (e.g., six cartridges for a patient weighing 150 pounds [67.5 kg]).  Local anesthesia Classification Clinically available local anesthesia Selection of local anesthesia: possible adverse effects Effect of systemic disease or systemic condition on local anesthesia Clinical factors inferior alveolar nerve block alternative injection sites ✓ Possible adverse effects of local anaesthsia: Cardiovascular reactions (Tackycardia) Systemic effects (Acute toxicity) Methemoglobinemia (problem with metabolism of anesthetic) Peripheral nerve paresthesia, Allergic reactions to the anesthetic and/or latex, Reactions to anesthetics containing a sulfite antioxidant.  Local anesthesia Classification Clinically available local anesthesia Selection of local anesthesia Effect of systemic disease or systemic condition on local anesthesia Clinical factors inferior alveolar nerve block alternative injection sites Effects of systemic diseases or conditions on local anesthetics Local anesthetics may interact with a patient’s medications, so a thorough review of the medical history is an absolute requirement Use of local anesthetic solutions without vasoconstrictors (e.g., 3% mepivacaine) is a reasonable alternative for those adult patients. Local anesthesia Effects of systemic diseases or conditions on local anesthetics Cohens 12th edition Local anesthesia Effects of systemic diseases or conditions on local anesthetics ✓ Pregnant or lactating women Many of the commonly available local anesthetics are safe for use The US Food and Drug Administration (FDA) has classified lidocaine and prilocaine as category B and mepivacaine, bupivacaine, and articaine as category C. When local anesthetics with epinephrine or other vasoconstrictors are used in pregnant women, it is recommended to use the lowest concentration of the vasoconstrictor. In addition, the use of an aspiration technique to avoid inadvertent intravascular injection is required.  Local anesthesia Classification Clinically available local anesthesia Selection of local anesthesia Effect of systemic disease or systemic condition on local anesthesia Clinical factors anathesia used for inferior alveolar nerve block Alternative solution in IANB alternative injection sites Volume and concentration Factors of failure of inferior alveolar nerve block  How can you confirm pulpal anesthesia? Traditional methods of confirming anesthesia as: lip numbness, or soft tissue testing may not be effective in determining pulpal anesthesia. Pulpal anesthesia can be confirmed by using: 1. Cold refrigerant 2. Electric pulp tester  Mandibular anesthesia Inferior alveolar nerve block 1- 2% lidocaine and 1:100,000 epinephrine Anesthetic success for nerve blocks has been defined in the majority of studies as the percentage of subjects who achieve two consecutive nonresponsive readings on electrical pulp testing within 15 minutes and continuously sustain this lack of responsiveness for 60 minutes. The clinical condition would be pulpal anesthesia within 15 minutes that lasts for 1 hour. Local anesthesia Clinical factors , Inferior alveolar nerve block 2- Alternative anesthetic solutions for the inferior alveolar nerve block: ❑ I-Solutions without epinephrine ❑ II- Articaine with 1:100,000 or 1:200,000 epinephrine ❑ III- Long-acting anesthetics ❑ IV- Buffered lidocaine Local anesthesia Clinical factors , Inferior alveolar nerve block 2- Alternative anesthetic solutions for the inferior alveolar nerve block: ❑ I-Solutions without epinephrine Plain solutions (mepivacaine, prilocaine) have been found to obtain pulpal anesthesia for an IAN block at rates similar to those for lidocaine with 1:100,000 epinephrine the duration of pulpal anesthesia is reduced to approximately 50 minutes Local anesthesia Clinical factors , Inferior alveolar nerve block 2- Alternative anesthetic solutions for the inferior alveolar nerve block: ❑ II- Articaine with 1:100,000 or 1:200,000 epinephrine Articaine is classified as an amide. Local anesthesia Clinical factors , Inferior alveolar nerve block 2- Alternative anesthetic solutions for the inferior alveolar nerve block: ❑ III- Long-acting anesthetics Bupivacaine provides prolonged analgesia and is indicated when postoperative pain is anticipated, its duration of pulpal anesthesia in the mandible is almost twice lidocaine, as long as (4 hours) Local anesthesia Clinical factors , Inferior alveolar nerve block 2- Alternative anesthetic solutions for the inferior alveolar nerve block: ❑ IV- Buffered lidocaine Buffering lidocaine using sodium bicarbonate raises the pH of the anesthetic solution. Some studies found that buffered lidocaine produced less pain on injection and a faster onset of anesthesia Local anesthesia Clinical factors , Inferior alveolar nerve block 2- Alternative anesthetic solutions for the inferior alveolar nerve block: ❑ IV- Buffered lidocaine However, In symptomatic patients with a diagnosis of pulpal necrosis and associated acute swelling, no significant decrease in pain of infiltrations or significant decrease in the pain of an incision-and-drainage procedure was found when the buffered anesthetic formulation was used. Local anesthesia 3-Alternative injection sites and techniques Gow-gates and Vazirani-Akinosi techniques The Vazirani-Akinosi technique is indicated for cases involving a limited mandibular opening to assist with further opening. The Vazirani-Akinosi technique also has not been found to be superior to the standard inferior alveolar injection. Local anesthesia Alternative injection sites Gaw gates technique Cohens 12th edition Local anesthesia Alternative injection sites Cohens 12th edition Local anesthesia Alternative injection sites IANB techniques Local anesthesia 3- Alternative injection sites Articaine infiltrations Articaine is significantly better than lidocaine for buccal infiltration of the mandibular first molar. However, articaine alone does not predictably provide pulpal anesthesia of the mandibular first molar Local anesthesia 3- Alternative injection sites Articaine infiltrations In anterior teeth, buccal and lingual infiltrations of articaine provide initial pulpal anesthesia, but the anesthesia declines over 60 minutes.  Local anesthesia Volume and concentration Factors of failure of inferior alveolar nerve block Supplemental anesthesia for vital pulp in the mandible Infiltration IO IP Intraligamental Maxillary anesthesia Local anesthesia Volume and concentration Increasing the volume of 2% lidocaine with epinephrine to 3.6 mL (two cartridges) does not increase the incidence of pulpal anesthesia with the IAN block Also, no advantage has been seen in using a higher concentration (1:50,000 versus 1:100,000) of epinephrine Inadequate anesthesia in endodontic therapy is typically noted in lower molars with irreversible pulpitis Local anesthesia Causes of failure of the inferior alveolar nerve block: Accessory and cross innervation, the mylohyoid nerve is the accessory nerve most often cited as a cause of failure of mandibular anesthesia Injection accuracy, Needle beveling, Needle deflection.  Local anesthesia Volume and concentration Factors of failure of inferior alveolar nerve block Supplemental anesthesia for vital pulp in the mandible o Infiltration o Intra-Osseous o Intraligamentary o Intraseptal o Intra pulpal Local anesthesia Supplemental anesthesia for vital pulps in the mandible A supplemental injection is used if the standard injection is not effective. It is useful to repeat an initial injection only if the patient is not exhibiting the classic signs of soft-tissue anesthesia, such as profound lip numbness. Generally, if the classic signs are present, reinjection is not very effective  Supplemental injections include: Infiltration injection, Intra-Osseous (IO) injection, Intraligamentary (IL) injection (formerly called the periodontal ligament [PDL] injection), Intraseptal (IS) injection, Intrapulpal (IP) injection. Local anesthesia Supplemental anesthesia for vital pulps in the mandible I- Infiltrations Supplemental mandibular buccal, lingual, or buccal plus lingual infiltrations of articaine Buccal infiltration alone and buccal plus lingual infiltrations alone do not result in complete pulpal anesthesia Local anesthesia Supplemental anesthesia for vital pulps in the mandible II- Intraosseous anesthesia It is particularly useful in conjunction with an IAN block when it is likely that supplemental anesthesia will be necessary (e.g., in mandibular second molar teeth). The IO injection allows placement of a local anesthetic directly into the cancellous bone adjacent to the tooth. very effective irreversible pulpitis Local anesthesia Supplemental anesthesia for vital pulps in the mandible II- Intraosseous anesthesia When a primary IO injection was compared with an infiltration injection, the IO technique showed a quicker onset and a shorter duration of anesthesia The techniques for IO injection of anesthetic are the Stabident, X-Tip, or TNN system Supplemental anesthesia for vital pulps in the mandible II- Intraosseous anesthesia Stabident perforator X-Tip  Intraosseous injection Technique The Stabident and X-tip systems The technique involves three simple steps: 1. Anesthesia of the attached gingiva 2. Cortical bone perforation 3. Deposition of anesthetic solution into cancellous bone. The Stabident  Intraosseous injection: Technique 1. Anesthesia of the attached gingiva Using the ultrashort needles provided in the kit, inject a few drops of solution into the attached gingiva until slight blanching occurs  Intraosseous injection: Technique 2. Cortical plate perforation - A perforator (solid wire attached to a plastic hub used on a low speed hand piece. - A hole is made through the cortical bone through which the anesthetic is deposited. - It is better to inject distal to the tooth rather than mesial except for maxillary and mandibular second molars, it is better mesial. -  Intraosseous injection: Technique 3. Injecting into cancellous bone Local anesthesia Supplemental anesthesia for vital pulps in the mandible II- Intraosseous anesthesia Septodont evolution needle Local anesthesia Supplemental anesthesia for vital pulps in the mandible II- Intraosseous anesthesia One of the benefits of the IO injection is the reported immediate onset of anesthesia. The injection is recommended to be given distal to the tooth to be anesthetized. The exception to this rule would be the maxillary and mandibular second molars, for which a mesial site injection would be needed.  Supplemental anesthesia for vital pulps in the mandible II- Intraosseous anesthesia The perforation site for the IO injection should be equidistant between the teeth and in the attached gingiva to allow for the perforation to be made through a minimal thickness of tissue and cortical bone and to prevent damage to the roots of the teeth Local anesthesia Supplemental anesthesia for vital pulps in the mandible II- Intraosseous anesthesia The duration of anesthesia for a supplemental IO injection in patients with irreversible pulpitis has been reported to last the entire debridement appointment of approximately 45 minutes. Complications: transient increase in heart rate with both the Stabident and X-Tip systems when injecting epinephrine- and levonordefrin-containing anesthetic solutions Supplemental anesthesia for vital pulps in the mandible III- Intraligamentary anesthesia PDL injections are usually given using either a standard dental anesthetic syringe or a high- pressure syringe or using computer-controlled anesthetic delivery systems. The citoject syringe A computer-assisted local anesthetic delivery system; The Wand  Local anesthesia Supplemental anesthesia for vital pulps in the mandible III- Intraligament anesthesia The key to giving a successful PDL injection remains the attainment of back-pressure during the injection. Failure to get back-pressure will most likely lead to failure Local anesthesia Supplemental anesthesia for vital pulps in the mandible III- Intraligamentary anesthesia Mechanism of action An IL injection forces anesthetic solutions through the cribriform plate into the cancellous bone around the tooth. The primary route of anesthetic is not via the PDL. Bevel direction!! It is not a pressure anesthesia, rather than it should be considered an IntraOsseous injection. Local anesthesia Supplemental anesthesia for vital pulps in the mandible III- Intraligamentary anesthesia The onset of anesthesia is immediate with an IL injection, which means that no waiting period is required for the anesthesia to take effect. If anesthesia is still not adequate, reinjection may be necessary. Local anesthesia Supplemental anesthesia for vital pulps in the mandible III- Intraligamentary anesthesia Postoperative discomfort Postoperative pain occurs in one third to three quarters of patients, with a duration of 14 hours to 3 days. The discomfort is related to damage from needle insertion rather than to the pressure of depositing the solution. patients report that their tooth feels “high” in occlusion Supplemental anesthesia for vital pulps in the mandible IV- Intraseptal injection 27-gauge  Intraseptal injection * 0.2-0.4 ml of anesthetic solution is introduced into the dental papilla distal to the tooth to be treated. Advantages: Only a minimum volume of solution is required There is no lip and tongue anesthesia Immediate onset of action (less than 30 seconds) Presents very few postoperative complications  Supplemental anesthesia for vital pulps in the mandible IV- Intrapulpal injection In about 5% to 10% of mandibular posterior teeth with irreversible pulpitis, supplemental IO or IL injections, even when repeated, do not produce profound pulpal anesthesia This is an indication for the IP injection The intrapulpal injection works well when it is given under back-pressure. Local anesthesia Supplemental anesthesia for vital pulps in the mandible IV- Intrapulpal injection Onset of anesthesia is immediate. The key factor is giving the injection under strong back-pressure. Simply placing local anesthetic solution in the pulp chamber passively will not achieve adequate pulpal anesthesia.  Supplemental anesthesia for vital pulps in the mandible IV- Intrapulpal injection Disadvantages of the intrapulpal injection are: Its short duration of action (approximately 15–20 minutes), the pulpal tissue must be removed quickly and completely. In order to give the IP injection, the pulp must be exposed to allow direct injection The injection can be very painful for the patient. The patient should be warned to expect moderate to severe pain during the initial phase of the injection.  Local anesthesia Volume and concentration Factors of failure of inferior alveolar nerve block Supplemental anesthesia for vital pulp in the mandible Infiltration IO IP Intraligamental Maxillary anesthesia o Extending the duration of pulpal anesthesia for maxillary teeth  Maxillary anesthesia The most commonly used injection for anesthetizing maxillary teeth is infiltration with a cartridge of 2% lidocaine with 1:100,000 epinephrine. Infiltration results in a fairly high incidence of successful pulpal anesthesia (around 87% to 92%).  Maxillary anesthesia Pulpal anesthesia usually occurs within 3 to 5 minutes. Pulpal anesthesia of the anterior teeth declines after about 30 minutes, with most losing anesthesia by 60 minutes. In premolars and first molars, pulpal anesthesia is good until about 40 to 45 minutes and then it starts to decline.  Maxillary anesthesia Extending the duration of pulpal anesthesia for maxillary teeth A two-cartridge volume of 2% lidocaine with epinephrine extends the duration of pulpal anesthesia, but not for 60 minutes. Adding another cartridge of 2% lidocaine with epinephrine at 30 minutes in anterior teeth and 45 minutes in posterior teeth significantly improves the duration of pulpal anesthesia and may be the best way to extend the duration of pulpal anesthesia Refrences Cohen’s “Pathways of the pulp”, 12th edition, chapter 6 “Endodontics” by Ingle; 7th edition, chapter 18 Arnaldo Castellucci; Endodontics, volumes I and II