DENTAL ANESTHESIA Rr. labiales sup. N. buccalis Rr. alveolares sup. ant. et medii Rr. alveolares sup. post. N. nasopalatinus Nn. palatini MAXILLA N. mentalis N. alveolaris inf. N. buccalis N. lingualis N. glossopharyngeus N. vagus MANDIBLE § Operative procedures require cutting through sensitive structures, producing extreme discomfort and pain § § Pain is a result of stimulation of nociceptors that are receptors preferentially sensitive to a noxious stimulus (Aδ, C fiber aferent axons) § § Local anesthetics (LA) cause: reversible block sensory nerve conduction of noxious stimuli from periphery to the CNS § increase - duration of action - depth of anesthesia § decrease - systemic toxic reactions - local bleeding The effectiveness of local anesthetics is improved by the addition of a vasoconstrictor: § To minimize anesthetic failure, the dentist must have a good knowledge of the anatomy of the head region, particularly the neuroanatomy of the maxillary and mandibular regions of the face ! § § Onset of action of anesthesia!!! General Potential Complications 1. Nerve injury 2. Injuries to blood vessels 3. Intraglandular injections 4. Trauma to muscles 5. Systematic reactions 1) Paresthesia (loss of sensation) - commonly involve the tongue and lower lip 2) 2) Hyperesthesia (increased sensitivity to painful stimuli) 3) 3) Dysesthesia (pain following nonnoxious stimuli) 4) 4) Dysgeusia (impaired sense of taste) 1. Nerve Injury 5) Xerostomia (reduced salivation) - the chorda tympani is traumatized 6) Ocular and extraocular symptoms The passive process of diffusion of anesthetic through the orbit leads to ocular and extraocular symptoms: - paralysis extraocular muscle - diplopia - amaurosis (temporary blindness) - Horner´s syndrome (enophthalmos, miosis, palpebral ptosis) § Intravascular injection → vascular damage → hemorrhage with hematoma formation § § If the vein is engaged, the bleeding is minimal and is usually evidenced a few days later § Artery damage with significant hematoma formation and extensive intra or extraoral swelling § § Potential anesthetizing sympathetic nerve may result vasoconstriction 2. Bleeding Transient paralysis of the ipsilateral facial muscles - caused by anesthesia of the facial nerve in parotid gland 3. Intraglandular injection Muscle trismus = spasm of jaw muscles, which restricts mouth opening (temporal and medial pterygoid muscle) 4. Trauma of muscle Failure of the cardiorespiratory system Anaphylaxis 5. Systematic complication Type of local anesthesia I. Local Infiltration Small nerve endings in the small area of soft tissue or bone are flooded with small amount of local anesthetic solution II. Nerve Block The local anesthetic solution is deposed within close proximity to a main peripheral nerve III. Field blocks Local anesthetic is deposited near a larger nerve trunks 3 The needle pervade at a height of insertion of mucobuccal fold to the apex and ... I. Local Infiltration DIright Correct bevel orientation Correct Incorrect the anesthetic agent is deposited supraperiostally ! Maxilla Local infiltration is successful in all parts of maxilla – both buccal and lingual The problem may be only on buccal plate at the 1st molar, which his roots are covered by the zygomatic process → the anesthetic usually doesn´t diffuse through the bone There is different composition of the cortical plate of maxillary and mandibulary alveolar process Mandible The cortical plate of the mandible is sufficiently dense to preclude effective infiltration anesthesia Thus, local is infiltration is ineffective, except mandibular incisors (buccal and lingual) Figure #15 Figure #14 1. Posterior superior alveolar - PSA 2. Middle superior alveolar - MSA 3. Anterior superior alveolar - ASA 4. Infraorbital 5. Greater palatine 6. Nasopalatine 7. Alveolar inferior (Halstead, Gow-Gates, Akinosi) 8. Mental 9. Lingual 10. Buccal II. Nerve Block Infraorbital nerve ASA MSA PSA 1. PSA Block § Anesthetize the pulps and periodontal ligaments of the maxillary molars, corresponding buccal alveolar bone and gingival tissue and posterior portion of the maxillary sinus. Mesiobuccal root 6 can be innervates by middle superior alveolar nerve ! § Technique - between 1st and 2nd molar at a height of insertion of mucobuccal fold, angle at 45° superiorly and medially 2. MSA Block § Anesthetize the maxillary premolars, corresponding buccal alveolar bone and gingival tissue § § Used if the infraorbital block fails to anesthetize premolars § Technique - between 1st and 2nd premolar at a height of insertion of mucobuccal fold § In the Czech republic MSA is a rarely used technique, more often are used local infiltration 3. ASA Block § Anesthetize the canine, incisors, corresponding buccal alveolar bone and gingival tissue § Technique - the area of lateral incisor at a height of insertion of mucobuccal fold In the Czech republic MSA is a rarely used technique, more often are used local infiltration 4. Infraorbital Nerve Block § Combinate ASA and MSA block § § Anesthetize the maxillary premolars, canine, incisors, corresponding buccal alveolar bone and gingiva, also the terminal branches of infraorbital nerve (lower eyelid, external nose tissue, upper lip, the anterior aspect of the maxillary sinus) § Technique - palpate infraorbital foramen → retract the upper lip → inject to area of 3/4 → contact bone in infraorbital region → inject 0,9 -1,2ml 5. Greater Palatine Nerve Block § Anesthetize all palatal mucosa of the side injected and lingual gingivae posterior to the maxillary canines and corresponding bone § Technique - on the hard palate between the 2nd and 3rd molars approximately 1cm medially, inject cca 0,3 - 0,5ml 6. Nasopalatine Nerve Block § Anesthetize the soft and hard tissue of the maxillary anterior six teeth - from canine one side to canine other side Technique - approximately 1,5 cm posterior to the alveolar crest between the central incisors - posterior to the incisive papilla; depth less than 10mm and inject 0,3 - 0,5 ml a) Halstead method b) Gow-Gates method c) Akinosi method 7. Inferior Alveolar Nerve Block § Individual variations in the locations of the mandibular foramen § § Be aware of the proximal extremity of the maxillary artery. Aspiration ! § The finger in the retromolar fossa with the fingernail poiting backward § A line is sighted from occlusal surfaces of the premolars of the opposite side to the midpoint of the fingernail § § Inject 0,5 - 1ml solution § § Continue to inject 0,5ml on removal from injection site to anesthetize the lingual branch a) Halstead Open-Mouth method an na NAI § Inject remaining anesthetic into coronoid notch region in the mucous membrane distal and buccal to most distal molar to perform a long buccal nerve block § Field block anesthesia § § The injection site is higher than Halstead § § Below the insertion of the lateral pterygoid muscle at the anterior side of the condyle at maximal opening in relatively avascular area § § The injection line is parralel with the external line from the intertragal notch to the angle of the mouth b) Gow-Gates method § The diffusion of the anesthetic solution reach all three oral sensory portion of mandibular branch V.n. and other sensory nerves in this region § § High success rate, fewer complication x slower rate of onset Figure #10 § Field block anesthesia § § For patient with limited opening due trismus, ankylosis, fracture § The gingival margin above the maxillary 2nd and 3rd molars and the pterygomandibular raphae serve as landmarks for this technique c) Vazirani-Akinosi closed mouth method § The needle is advanced through the mucous membrane and buccinator muscle to enter the pterygomandibular space § § Penetrate to a depht 25mm figure13 § Remaining anesthetic in long buccal nerve area 8. Mental Nerve Block § Terminal branch of the inferior alveolar nerve, exits the mandible via the mental foramen § § The position of this foramen is most frequently near the apex of the mandibular 2nd premolar § § The foramen open upward and slightly posteriorly! § Anesthetized lower lip, chin, labial gingiva, alveolar mucosa, pulpal/periodontal tissue for the canine, incisors and premolars on side blocked § Technique The tip of needle be directed or anterior to approximate the position of the foramen, but not enter the foramen ! Penetrate to a depth 5 mm, inject 0,5 - 1,0 ml To provide incisive nerve anesthesia via the application of finger pressure over the foramen after local anesthetic solution is deposited there Mental nerve ment 9. Lingual Nerve Block § Nerve passes from the infratemporal fossa into the floor of the mouth, in the vicinity of the 2nd and 3rd molars, is quite vulnerable § § Is anesthetizes during the inferior alveolar nerve block or with a bolus of anesthetic solution injected after an inferior alveolar nerve block § Anesthetized anterior ⅔ of the tongue, lingual gingiva and adjacent mucosa Lingual nerve Figure #7 10. Buccal Nerve Block § Arises in the infratemporal fossa and crosses the anterior border of the ramus to give multiple branches § § Supplies buccal gingiva and mucosa of the mandible for a variable length, from the vicinity of the 3th molar to the canine Buccal nerve block. (Daniel/Harfst, 2002, courtesy of the OHSU Department of Dental Hygiene) Technique - anterior ramus of the mandible at the level of the mandibular molar occlusal plane in the vicinity of the retromolar fossa Buccalnerve Buccal nerve Lingual nerve Inferior alveolar nerve Mental nerve Alternative delivery methods 1. Intraosseous injection 2. Intraligamentary injection 3. Intrapulpal injection 4. Topical anesthetic patches 1. Intraosseous Injection § Involves the placement of anesthetic solution directly into the cancellous bone adjacent to the tooth to be anesthetized, and allows for rapid onset of profound pulpal anesthesia § § The site of injection involves the attached gingiva 2mm apical to the gingival margin and interproximal relative to the teeth § § Provide anesthesia of a single tooth or multiple teeth in a quadrant 2009-images The first step - to drill a small hole through the soft tissue and cortical bone to a depth of 5 – 8mm 2009-images The second step - inserting a needle to the same depth and manually injected the desired volume of anesthetic solution into the cancellous bone 2. Intraligamentary Injection § Is occasionally used as the sole technique for anesthesing a single tooth § The needle is inserted, directly along the long axis and as apically as possible, through the gingival sulcus and into the periodontal ligament between the tooth and the alveolar bone § § Slowly injected approximately 0,2ml of anesthetic solution under pressure to control the pain of the associated tooth 4534dd2 Contraindication: - deciduous teeth - periodontal infection 3. Intrapulpal Injection § When pulp chamber has been exposed and treatment can´t proceed § Technique - a small needle is insetred into the pulp chamber until resistance is encountered → injected under the pressure § § As the injection is startes there will be a brief moment of intense discomfort ANd9GcQRb0LahYCIA3VZN_iguPAG0-pvDpkiXpTEJA_NgpterA5pXnfQ-A 4. Topical anesthetic patches § Be indicated to minimize the sensation of needle insertion or for very brief relief from painful mucosal lesions § § A bioadhesive patch impregnated with 10% or 20% lidocaine § § Typically, is used to anesthetize only the outer 1-3 mm of mucosa, not deeper structures 1_38598_FS Topex Topical Anesthetic Gel Spray Gel Maxilla Infraorbital nerve block Nasopalatine block Greater palatine block Posterior superior alveolar block Middle superior alveolar block Anterior superior alveolar block Mandible Buccal block Inferior alveolar block Incisive block