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I NNERVATION & VASCULARIZATION OF THE ORAL REGION. 13.December.2011 Tuesday. Kaan Yücel M.D., Ph.D. Oral Region. Oral cavity , teeth , gingivae , tongue , palate & R egion of the palatine tonsils
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INNERVATION & VASCULARIZATION OF THE ORAL REGION 13.December.2011 Tuesday Kaan Yücel M.D., Ph.D.
Oral Region Oral cavity,teeth, gingivae, tongue, palate & Region of the palatine tonsils The oral cavity is where food is ingested and prepared for digestion in the stomach and small intestine.
Blood is supplied to the oral vestibule and oral cavity via branches of external carotid artery Facial Maxillary Lingual
Venous Drainage SupratrochlearVein Supraorbital Vein Facial Veinprovides the major venous drainage of the face. Beginsat the medial canthus of the eye by the union of the supraorbital and supratrochlearveins and ends by draining into the internal jugular vein Superficial Temporal Vein Retromandibular Vein Union of the superficial temporal and maxillary veins
Multiple nerves innervate the oral cavity General sensory innervation predominantly by branches of the trigeminal nerve [V]: Upperparts of the cavity, including the palate and the upper teeth, are innervated by branches of the maxillary nerve [V2] Lowerparts, including the teeth and oral part of the tongue, are innervated by branches of the mandibular nerve [V3] Taste(special afferent-SA) from the oral part or anterior two-thirds of the tongue is carried by branches of the facial nerve [VII], which join and are distributed with branches of the trigeminal nerve [V]
Parasympatheticfibers to the glands within the oral cavity are also carried by branches of the facial nerve [VII], which are distributed with branches of the trigeminal nerve [V]. Sympathetic fibers in the oral cavity ultimately come from spinal cord level T1, synapse in the superior cervical sympathetic ganglion, and are eventually distributed to the oral cavity along branches of the trigeminal nerve [V] or directly along blood vessels.
All muscles of the tongue are innervated by the hypoglossal nerve [XII], except thepalatoglossus, which is innervated by vagusnerve [X].
All muscles of the soft palate are innervated by the vagus nerve [X] except for the tensor velipalatini, innervated by a branch from the mandibular nerve [V3]. The muscle (mylohyoid) that forms the floor of the oral cavity is also innervated by the mandibular nerve [V3].
SensoryInnervation Innervation of thetongue is complexandinvolves a number of nerves. Anterior two thirds:General sensory innervationcarried by the lingual nerve (V3). The lingual nerve also carries parasympathetic and taste fibers from the oral part of the tongue that are part of [VII].
Taste (SA) fromthe oral part of thetongue is carriedintothecentralnervoussystembythefacialnerve[VII]. • Specialsensory (SA) fibers of thefacialnerve [VII] leavethetongueand oral cavity as part of thelingualnerve. • Thefibersthenenterthechordatympaninerve, which is a branch of thefacialnerve [VII] thatjoinsthelingualnerve in theinfratemporal fossa.
Posteriorthird:Taste (SA) and general sensationfromthepharyngealpart of thetonguearecarriedbytheglossopharyngealnerve [IX].
Course of parasympatheticinnervation of theparotidgland GVE fibers of CN IX Tympanicnerve (branch of CN IX) LesserpetrosalnerveOticganglionAuriculotemporalnerve (branch of mandibularnerve) Parotidgland Sympatheticinnervation Externalcarotidplexus (superiorcervicalganglion)
Nerve Supply of the submandibular gland Parasympatheticsecretomotorsupply is fromthefacialnerveviathechordatympani, andthesubmandibularganglion.
Course of parasympatheticinnervation of thesubmandibulargland GVE fibers of CN VII Chordatympani (branch of CN VII) Lingualnerve (branch of mandibularnerve) SubmandibularganglionPostsynapticfibersfollowthearteriesSubmandibulargland Sympatheticinnervation Externalcarotidplexus (Superiorcervicalganglion)
Vasculature of teeth Posterior superior alveolar artery & inferior alveolar artery branches of the maxillary artery, supply the maxillary and mandibular teeth, respectively. Alveolar veins with the same names & distribution accompany arteries. Lymphatic vessels from the teeth and gingivae pass mainly to the submandibular lymph nodes, as well as into submental and deep cervical lymph nodes.
Innervation of teeth Branches of the superior (CN V2) & inferior (CN V3) alveolar nerves give rise to dental plexuses that supply the maxillary and mandibular teeth.
The gingivae are supplied by multiple vessels; Inferior alveolar artery Lingual artery Anterior & posterior superior alveolar arteries (branches of the infra-orbital and maxillary arteries, respectively) Nasopalatine & greater palatine arteries Veins from the gingivae follow the arteries and ultimately drain into the facial vein or into pterygoid plexus of veins. Vasculature of gingivae
Innervation of gingivae Like the teeth, the gingivae are innervated by nerves that ultimately originate from the trigeminal nerve [V]: Gingiva associated with the upper teeth by branches of the maxillary nerve [V2] Gingiva associated with the lower teeth by branches of the mandibular nerve [V3]
Anesthesia of the Trigeminal Nerve 13.December.2011 Tuesday Kaan Yücel M.D., Ph.D.
ANESTHESIA OF THE MAXILLARY TEETH From an anatomicalperspective, maxillaryinjectionsgenerallyarebelievedto be not onlymorepredictablethanmandibularinjections, but alsomorebenignandassociatedwithfewercomplications. However, this is not necessarilytrue, particularlyforblockinjections.
Techniques of Maxillary Regional Anesthesia • The techniques most commonly employed in maxillary anesthesia include • Supraperiosteal (local) infiltration • Periodontal ligament (intraligamentary) injection • Posterior superior alveolar nerve block • Middle superior alveolar nerve block • Anterior superior alveolar nerve block • Greater palatine nerve block • Nasopalatine nerve block • Local infiltration of the palate • Intrapulpal injection • Of less clinical application are the maxillary nerve block and intraseptal injection.
ANESTHESIA OF THE MAXILLARY TEETH Maxillarynerveblock (V2 block) can be usedtoanesthetizemaxillaryteeth, alveolus, hard andsofttissue on thepalate, gingiva, and skin of thelowereyelid, lateralaspect of nose, cheek, andupperlip skin andmucosa on sideblocked.
POSTERIOR SUPERIOR ALVEOLAR (PSA) NERVE BLOCK The PSA nerveblock is usedtoanesthetizethepulpaltissue, correspondingalveolar bone, andbuccalgingivaltissuetothemaxillary 1st, 2nd, and 3rd molars.
POSTERIOR SUPERIOR ALVEOLAR (PSA) NERVE BLOCK Thearea of insertion is theheight of mucobuccalfoldbetween 1st and 2nd ndmolar.
MIDDLE SUPERIOR ALVEOLAR (MSA) NERVE BLOCK • Useful for procedures where the maxillary premolar teeth or the mesiobuccal root of the 1st molar require anesthesia. • Although not always present, it is useful if the PSA or ASA nerve blocks or supraperiosteal infiltration fails to achieve adequate anesthesia. Present in about 28% of the population. The height of the mucobuccal fold above the maxillary 2nd premolar is the injection site.
ANTERIOR SUPERIOR ALVEOLAR (ASA) NERVE BLOCK The ASA nerveblock is usedtoanesthetizethemaxillary canine, lateralincisor, centralincisor, alveolus, andbuccalgingiva. The area of insertion is height of mucobuccal fold in area of lateral incisor and canine. The mucobuccal fold over the maxillary first premolar is another suggested site for injection.
ANTERIOR SUPERIOR ALVEOLAR (ASA) NERVE BLOCK Inordertoanestheticallyblocktheanteriorandmiddlesuperioralveolarnerves, it is essentialtolocalizetheinfraorbitalforamenwhich, whenreachedwith a needle, permitsthediffusion of theanestheticsolutionthroughtheinfraorbitalcanal.
INFRAORBITAL(ASA) NERVE BLOCK The area of insertion is height of mucobuccal fold in area of lateral incisor and canine.
ANTERIOR SUPERIOR ALVEOLAR (ASA) NERVE BLOCK Theanatomicallocation of thisforamen has beenstudiedbynumerousauthors. MartaniandStefani (1965), studyingtheposition of thisanatomicaccidentwithinstatistical, morphologicalandtopographicalaspects, provide an extensivebibliographicalreview of thistopic.
ANTERIOR SUPERIOR ALVEOLAR (ASA) NERVE BLOCK Inadults, theinfraorbitalforamenliessignificantlybelowtheinfraorbitalrim (8 to 10 millimeters), a safedistancefromthecavity of theorbit.
ANTERIOR SUPERIOR ALVEOLAR (ASA) NERVE BLOCK Insert the needle over the first premolar toward the infraorbital foramen. The needle should be held parallel with the long axis of the tooth. Advance the needle toward the upper rim of the infraorbital foramen beneath the tip of the index.
ANTERIOR SUPERIOR ALVEOLAR (ASA) NERVE BLOCK Tolocatetheinfraorbitalforamen, thedentist can palpate a smalldepression in theinfraorbitalrim—theinfraorbitalnotch—createdbythezygomaticomaxillarysuture. Placeyour in thisnotch, anddirecttheneedlethroughthevestibularmucosaoverthefirstpremolartoothandtowardthefinger.
PALATAL INNERVATION Themucosa of the hard palateandthepalatalgingivaaresuppliedbythenasopalatineandgreaterpalatinenerves. Theboundarybetweentheareasinnervatedbythetwonervescorrespondsroughlyto a linedrawnbetweenthemaxillarycanines; however, thetwoareasare not sosharplydelineated as suchanimaginarylinemightsuggest.
NASOPALATINE NERVE BLOCK Thenasopalatinenerveblock can be usedtoanesthetizethesoftand hard tissue of themaxillaryanteriorpalatefrom canine to canine. The area of insertion is immediately lateral to the incisive papilla into incisive foramen to completely anesthetize the central incisors
GREATER PALATINE NERVE BLOCK Inthegreaterpalatinecanaltechnique, thearea of insertion is greaterpalatinecanal. Thetargetarea is themaxillarynerve in thepterygopalatine fossa. The dentist performs a greater palatine block and waits 3 3-5 mins. Then h/she inserts needle in previous area and walks into greater palatine foramen.
GREATER PALATINE NERVE BLOCK Theforamen has beenshowntolie 1.9 mm in front of theposteriorborder of the hard palateand 15 mm fromthepalatalmidline. Thesemeasurementsareusefulformoreeasilylocatingthegreaterpalatineforamenandenhancingtheanestheticinjectiontechnique in theposteriorpalate.
GREATER PALATINE NERVE BLOCK The greater palatine foramen can be located by on the palatal tissue approximately one centimeter medial to the junction of the 2nd and 3rd molar. While this is the usual position for the foramen, it may be located slightly anterior or posterior to this location.
ANESTHESIA OF THE MANDIBULAR TEETH Thebuccalcorticalplate of themandiblemostoften is sufficiently dense toprecludeeffectiveinfiltrationanesthesia in itsvicinity. Theinfiltrationtechniques do not work in theadultmandibleduetothe dense cortical bone. Therefore, thedentistmustrely on blockanesthesiaforeffectivelyanesthetizingmandibularteeth.
ANESTHESIA OF THE MANDIBULAR TEETH Nerveblocksareutilizedtoanesthetizetheinferioralveolar, lingual, andbuccalnerves. Itprovidesanesthesiatothepulpal, alveolar, lingualandbuccalgingivaltissue, and skin of lowerlipandmedialaspect of chin on sideinjected.
INFERIOR ALVEOLAR NERVE BLOCK Themostcommonapproachtoinferioralveolaranesthesia is thetraditionalHalsteadmethod. Inferioralveolarnerve is approached in thepterygomandibularspace, calledtheinfratemporal fossa, via an intraoralroutelocatedjustbeforethenerveentersthemandibularforamen.
INFERIOR ALVEOLAR NERVE BLOCK Thearea of insertion is themucousmembrane on themedialborder of themandibularramus at theintersection of a horizontalline (height of injection) andverticalline (anteroposteriorplane). Injection in proper area of ramus to effect alveolar nerve block Identifyingmandibularramus
INFERIOR ALVEOLAR NERVE BLOCK As thetarget site forthedeposition of anestheticsolution in theconventionalinferioralveolarblockinjection, themandibularforamenis an essentialstructuretoaccuratelylocate. Thetechniqueinvolvesblockingtheinferioralveolarnervepriortoentryintothemandibularlingula on themedialaspect of themandibularramus.
INFERIOR ALVEOLAR NERVE BLOCK Duringadministration of anesthetictotheinferioralveolarnerve, theclinicianmust be aware of theproximalextremity of themaxillaryartery, as well as thecourse of theinferioralveolarartery.
Traditionally, theinferioralveolarnerveblock (IANB), alsoknown as the “standardmandibularnerveblock” orthe “Halstedblock,” has a success rate of only 80 to 85 percent, withreports of evenlowerrates. • Investigatorshavedescribedothertechniques as alternativestothetraditionalapproach, of whichtheGow-Gates mandibularnerveblockandAkinosi-Vaziraniclosed-mouthmandibularnerveblocktechniqueshaveprovento be reliable. • Dentistswhoknowhowtoperformallthreetechniquesincreasetheirprobability of providingsuccessfulmandibularanesthesia in anypatient.
Theprimarygoal of each of thethreemandibularnerveblocksis anesthesia of theinferioralveolarnerve, whichinnervatesthepulps of themandibularteeth on thesameside of themouth, as well as thebuccalperiodontiumanteriortothementalforamen. Foreach of thethreetechniques, thisgoal is accomplishedbydepositinganestheticwithinthepterygomandibularspace.
GOW-GATES MANDIBULAR NERVE BLOCK DescribedbyGow-Gates in 1973. Theobjective of thetechnique Toplacetheneedle tip andadministerthelocalanesthetic at theneck of thecondyle. Thisposition is in proximitytothemandibularbranch of thetrigeminalnerveafter it exitstheforamen ovale.