Inferior alveolar nerve

IANB AND ITS REASONS FOR FAILURE

1. DR. AISHWARYA ARYA POST GRADUATE MM COLLEGE OF DENTAL SCIENCES, HARYANA INFERIOR ALVEOLAR NERVE BLOCK AND ITS COMPLICATIONS 1

2. CONTENTS Introduction Indications and contraindications Nerves and regions anesthesize Landmarks Techniques Procedure Signs and symptoms Complications Reasons of failure 2

3. Three large branches arise from trigeminal nerve V1- Ophthalmic nerve, V2- Maxillary nerve, V3- Mandibular nerve The third division V3- Mandibular nerve of the trigeminal nerve gives off branches in three areas from the - BRANCHES FROM UNDIVIDED NERVE BRANCHES FROM DIVIDED NERVE NERVUS SPINOSUS NERVE TO INTERNAL PTERYGOID MUSCLE ANTERIOR DIVISION POSTERIOR DIVISION 3 TRIGEMINAL NERVE

4. The posterior division of trigeminal nerve is primarily sensory with a small motor component. It descends for a short distance downward and medial to the lateral pterygoid muscle, at which point it branches into the Auriculotemporal Nerve Lingual Nerve Inferior alveolar nerves . 4

5. PATHWAY OF INFERIOR ALVEOLAR NERVE 5

6. It descends medial to the lateral pterygoid muscle and lateroposterior to the lingual nerve, to the region between the sphenomandibular ligament and the medial surface of the mandibular ramus, where it enters the mandibular canal at the level of the mandibular foramen. 6

7. The nerve, artery, and vein travel anteriorly in the mandibular canal as far forward as the mental foramen, where the nerve divides into its terminal branches near the apex of second premolar into- the Incisive nerve the Mental nerve. 7

8. The inferior alveolar nerve block (IANB), commonly referred to as the mandibular nerve block, is the second most frequently used (after infiltration) and possibly the most important injection technique in dentistry. Unfortunately, it also proves to be the most frustrating, with the highest percentage of clinical failures even when properly administered. INDICATIONS Procedures on multiple mandibular teeth in one quadrant Surgical procedures on mandibular teeth and supporting structures when supplemented by anesthesia of lingual and long buccal nerve. When buccal soft tissue anesthesia (anterior to the mental foramen) is necessary When lingual soft tissue anesthesia is necessary CONTRAINDICATIONS Infection or acute inflammation in the area of injection (rare) Patients who are more likely to bite their lip or tongue, for instance, a very young child or a physically or mentally handicapped adult or child 8

9. NERVES ANESTHETIZED Inferior alveolar nerve and its subdivisons Occasionally lingual and buccinator nerves AREAS ANESTHETIZED Mandibular teeth up to the midline Body of the mandible Inferior portion of the ramus Buccal mucoperiosteum Mucous membrane anterior to the mental foramen (mental nerve) Anterior two thirds of the tongue and floor of the oral cavity (lingual nerve) Lingual soft tissues and periosteum (lingual nerve) 9

10. LANDMARKS Muccobuccal fold Anterior border of ramus of mandible External oblique ridge Retromolar triangle Internal oblique ridge Pterygomandibular ligament Buccal sucking pad Pterygomandibular space AREA OF INSERTION Mucous membrane on the medial (lingual) side of the mandibular ramus, at the intersection of two lines One horizontal- representing the height of needle insertion, Other vertical- representing the anteroposterior plane of injection 10

11. TARGET AREA 11

12. PROCEDURE A long dental needle is recommended for the adult patient. A 25-gauge or a 27 gauge long needle is preferred. a Assume the correct position . (1)For a right IANB, a right-handed administrator should sit at the 8 o'clock position facing the patient (2)For a left IANB, a right-handed administrator should sit at the 10 o'clock position facing in the same direction as the patient b Position the patient supine (recommended) or semisupine (if necessary). The mouth should be opened wide to allow greater visibility of, and access to, the injection site. c Locate the needle penetration (injection) site. The posterior border of the mandibular ramus can be approximated intraorally by using the pterygomandibular raphe as it turns superiorly toward the maxilla. 12

13. NEEDLE INSERTION SITE 13

14. Three parameters must be considered during administration of IANB T he height of the injection The anteroposterior placement of the needle (which helps to locate a precise needle entry point ) The depth of penetration (which determines the location of the inferior alveolar nerve) 14

15. HEIGHT OF INJECTION Place the index finger or the thumb of your left hand in the coronoid notch (a) An imaginary line extends posteriorly from the fingertip in the coronoid notch to the deepest part of the pterygomandibular raphe (as it turns vertically upward toward the maxilla), determining the height of injection. (b) The finger on the coronoid notch is used to pull the tissues laterally, stretching them over the injection site, (c) The needle insertion point lies three fourths of the anteroposterior distance from the coronoid notch back to the deepest part of the pterygomandibular raphe . t 15

16. Site of needle insertion Verification of length of needle entry from the anterior border of the ramus Barrel of syringe brought to contralateral side and the needle closeness to the bone is verified and solution deposited 16

17. TECHNIQUE IN PEDIATRIC PATIENT The mandibular foramen is situated at a level lower to the occulusal plane of primary teeth in pediatric patient. Hence the injection is made slightly lower and more posteriorly than adult patients. 17

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19. SIGNS AND SYMPTOMS SUBJECTIVE SYMPTOMS Tingling and numbness of lower lip After the lingual nerve is affected numbness is felt on the tip of the tongue OBJECTIVE SYMPTOMS Instrumentation necessary to demonstrate absence of pain sensation 19

20. DISADVANTAGES One injection provides a wide area of anesthesia - useful for quadrant dentistry. Wide area of anesthesia (not indicated for localized procedures) Rate of inadequate anesthesia (31% to 81%) I ntraoral landmarks not consistently reliable Positive aspiration (10% to 15%, highest of all intraoral injection techniques) Lingual and lower lip anesthesia , discomfiting to many patients and possibly dangerous (self-inflicted soft tissue trauma) for certain individuals Partial anesthesia possible where a bifid inferior alveolar nerve and bifid mandibular canals are present; cross-innervation in lower anterior region ADVANTAGES 20

21. REASONS BEHIND FAILURE OF IANB It is commonly stated that the significantly higher failure rate of 15-20% for mandibular anesthesia This is related to- The thickness of the cortical plate of bone in the adult mandible. Difficulty with the is the absence of consistent landmarks . Branching of the inferior alveolar nerve in edentulous patients 21

22. Variant branching patterns of the inferior alveolar nerve 22

23. Studies have shown the patients who are more anxious prior to the procedure; experience a higher amount of pain. The mandibular hard tissue and soft tissue is supplied by a plexus of nerves . This plexus, may allow sensation even if primary inferior alveolar nerve is blocked. In 1020% of the cases, Mylohyoid nerve provides accessory innervation to mandibular molars TYPE OF ANESTHETIC SOLUTION USED- Cohen et al. showed that 3% mepivacaine is as effective as 2% lidocaine with 1:100 000 epinepthrine in achieving pulpal anaesthesia with IANB. Pulpal inflammation and abscess is a major problem when introducing anesthesia.[11] Studies have shown changes in the impulse generation of nerve fibres in presence of inflammation and also suggest changes in peripheral sensory fibers in presence of inflammation. 23

24. Presence of a bifid mandibular canal occurs at a rate of 0.35%. This can lead to missing one of the canals which may actually contain the nerve leading to inadequate or no anesthesia 24

25. ALTERNATIVES Mental nerve block, for buccal soft tissue anesthesia anterior to the first molar Incisive nerve block, for pulpal and buccal soft tissue anesthesia of teeth anterior to the mental foramen (usually second premolar to central incisor) Supraperiosteal injection, for pulpal anesthesia of the central and lateral incisors, and sometimes the premolars and molars (discussed fully in Chapter 20) Gow -Gates mandibular nerve block Vazirani-Akinosi mandibular nerve block PDL injection for pulpal anesthesia of any mandibular tooth IO injection for pulpal and soft tissue anesthesia of any mandibular tooth, but especially molars 25

26. Failure of inferior alveolar nerve block Exploring the alternatives- GAUTAM A. MADAN, M.D.S.; SONAL G. MADAN, M.D.S.; ARJUN D. MADAN, M.D.S. 26

27. REFERENCES Handbook of Local Anesthesia 6th ed. Stanley F. Malamed, DDS Monheims – local anesthesia and pain control in dental practice- C RICHARD BENNET Sicher and dubrul - Oral Anatomy Articles- A basic review on the inferior alveolar nerve block techniques Hesham Khalil- Department of Maxillofacial Surgery, College of Dentistry, King Saud University, Riyadh, Saudi Arabia FAILURE OF INFERIOR ALVEOLAR NERVE BLOCK (IANB) AND TECHNIQUES TO AVOID IT. - Dr. Harsh Rajvanshi , 2Dr. Sandra Ernest, 3Dr. Hafsa Effendi, 4Dr. Sarah Afridi, 5Dr. Madhur Chhabra, 6Dr. Navneet Kaur Inferior alveolar nerve block: Alternative technique- K. Thangavelu ,  R. Kannan , and  N. Senthil Kumar Failure of inferior alveolar nerve block Exploring the alternatives- GAUTAM A. MADAN, M.D.S.; SONAL G. MADAN, M.D.S.; ARJUN D. MADAN, M.D.S. Variant Inferior Alveolar Nerves and Implications for Local Anesthesia Kevin T. Wolf, BS,* Everett J. Brokaw, BA,* Andrea Bell, DMD, MS,† and Anita Joy, BDS, PhD‡ 27

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