 Hello everyone welcome back to another session in dentistry and more. Today's topic in oral surgery is inferior alveolar nerve block or IANB so it is a quadrant dentistry nerve block so it means it can be used for a third quadrant or fourth quadrant the entire quadrant procedures can be done with the help of this single nerve block so buckle nerve block also sometimes will be given along with IANB only if the soft tissue anaesthesia and the buckle posterior region for that quadrant is necessary and the nerves which anaesthetized are inferior alveolar nerve, incisive nerve, mental nerve and lingual nerve and as you see here the area anaesthetized are mandibular teeth to the midline, body of the mandible, inferior portion of the ramus, buckle, mucoperiosteum, mucus membrane anterior to the mandible of first molar that is through mental nerve then anterior two-third of the tongue and floor of the oral cavity that is through lingual nerve again lingual soft tissues and periosteum again through the lingual nerve so what are the indications of IANB so the first thing is procedure on multiple mandibular teeth in one quadrant or when buckle soft tissue anaesthesia that is anterior to the first molar is necessary or when lingual soft tissue anaesthesia is necessary all these cases we can opt for IANB but the contraindications are infection the presence of infection or acute inflammation and the area of injection so that is very rare but if infection is there the effectiveness of LA the LA won't work properly so we won't get the desired anaesthesia and it is contraindicated in patients who might be biting either the lipotung they have the habit of this biting lipotung such as a very young child or physically or mentally hand-capped adult or child because there'll be lingual nerve block which is giving anaesthesia to basically the tongue and and the lips also will be anesthetized so they might be having a tendency to bite on it so once anaesthesia effect is over the chances of pain because they might have accidentally injured the tongue or lips because the anaesthesia effect might be obscuring the actual pain so in such patients we should be very careful we should not opt for IANB rather we can go for infiltration technique now let's see the technique of IANB okay so the first thing is 25 gauge long needle is recommended for the adult patient 25 gauge and area of insertion okay so as you see the picture it is a mucus membrane on the medial side of mandibular ramus at the intersection of two lines one horizontal line representing the height of injection and other vertical representing the anterior posterior plane of injection so that is the area of insertion one horizontal which is representing the height of injection and the vertical which is representing the anterior posterior plane of injection and the target area inferior alveolar nerve as it passes downward toward the mandibular foramen but before it enters into the foramen that is a target area next is a landmarks so as you see here the landmarks first one is coronoid notch that is the greatest concavity on the anterior vortiframus then the tergo mandibular rafae then the occlusion plane on the mandibular posterior teeth so these are the landmarks so the procedure so as you see the picture here for right inferior alveolar nerve block a right handed dentist should sit at eight o'clock position facing the patient okay so right handed person sit at eight o'clock position for a left IANB a right handed administer or dentist should sit at ten o'clock position okay so for right IANB this is for right IANB and this is for left IANB this is the eight o'clock and ten o'clock and the procedure first the position of the patient that is supine mostly recommended or semi supine position the mouth should be open wide to permit greater visibility and access to the injection site next is a procedure so there are three parameters that must be considered during the administration of IANB the first one is a height of injection okay and the second one is anterior posterior placement of the needle so which helps to locate a precise needle entry point and then the depth of penetration so that determines the location of the inferior alveolar nerve so these three parameters must be considered as a height of injection anterior posterior placement and the depth of penetration so the first thing is height of injection as you see here in the picture we need to place the index finger or thumb of your left hand in the coronoid notch this is a coronoid notch here we need to keep anyway your right hand is having a loaded syringe so left hand the thumb should be placed at the coronoid notch an imaginary line extents posteriorly from the fingertip in the coronoid notch to the deepest part of pterigomantibular raffae okay so as it turns vertically upward towards the maxilla so pterigomantibular raffae is vertically upward towards the maxilla and which determines the height of injection so this imaginary line should be parallel with the occlusion plane of mantibular teeth so that is how we find the height of injection we need to place the index finger at the coronoid notch and there will be an imaginary line which extends posteriorly from the fingertip and the coronoid notch to the deepest part of pterigomantibular raffae so you can see the picture here the placement of the syringe barrel at the corner of the mouth usually corresponding to the premolars so the needle insertion point lies three fourth of the anterior posterior distance from the coronoid notch back to the deepest part of pterigomantibular raffae so you can see the finger and the needle insertion site okay so that needle insertion site lies three fourth of the anterior posterior distance from the coronoid notch back to the deepest part of pterigomantibular raffae then we have the anterior posterior placement of needle so needle penetration occurs at the intersection of two points okay that is the point one falls along the horizontal line okay horizontal line which is from the coronoid notch to the deepest part of pterigomantibular raffae as it essence vertically towards the palate so here we have the pterigomantibular raffae and this is the coronoid notch okay so this is the horizontal line so that we should keep in mind then the point two point two is a vertical line through point one about three fourth of the distance from the anterior border of the ramus so this vertical line which is crossing the horizontal line which is from the three fourth of the distance from anterior border of ramus that determines the anterior posterior site of injection so the intersecting line will be the needle penetration point so it's not very easy to draw in a two-dimensional board so you can see the picture here where exactly the needle should be going on a horizontal and vertical line intersection and penetration depth the ultimate success of IANB will be done only when we get a bone resistance the needle should be touching the bone that is a medial side of ramus of the mandible so the average depth of penetration to bony contact will be around 22 25 millimeter approximately two-third to three-fourth of the length of the long dental needle so two-third or three-fourth of the dental needle will be inside the tissue then only we get the bone resistance suppose if bone is contacted too soon less than half the length of long dental needle the dental tip is usually located too anteriorly on ramus okay so if you are getting dental needle it enters to the tissues it reaches just one half and we get bone resistance we are in a very anterior position so then we should withdraw the needle slightly but do not remove it from the tissue bring the syringe barrel towards the front of the mouth over the canine or lateral incisor on the contralateral side then redirect the needle until a more appropriate depth of insertion is obtained so the needle tip is now located posteriorly to the mandula sulcus and what if the bone is not contacted okay then the needle tip is usually located too far posterior so in order to correct this withdraw it slightly in tissue that is leaving approximately one-fourth its length in tissue and reposition the syringe barrel more posteriorly over the mandula molas and continue the insertion until contact with bone is made at an appropriate depth of 20 to 25 millimeters so if it is too anterior and too posterior also will be problem if it is too anterior the bone resistance will be obtained early and if it is too posterior will not get a bone resistance so we should correct it accordingly then the exact procedure is when bone is contacted withdraw approximately one millimeter to prevent superior still injection then aspirate if it is negative slowly deposit 1.5 ml of anesthetic over a minute of 60 seconds okay so 1.5 ml in one minute so slowly withdraw the syringe and when approximately half its length which is remain within the tissue we need to reasperate if negative deposit a portion of the remaining solution that is around 0.1 ml to anesthetize the lingual nerve okay lingual nerve then after approximately 20 seconds return the patient to upright or semi upright position wait for 3 to 5 minutes before commencing the dental procedure so what are the signs and symptoms so along with this I forgot to tell you INB along with this lingual nerve the long buckle nerve also will be given if soft tissue procedure is indicated in that area so that is more on a buckle side so we need to bring the needle towards the same side of the patient same side same quadrant and we need to give a long buckle now anesthesia so the sign so what are the signs and symptoms the subjective sign is tingling on numbness of lower lip which indicate anesthesia of mental nerve which is a terminal branch of inferior alveolar nerve so that is a good indication that inferior alveolar nerve is anesthetized although not a reliable indicator then there will be numbness of tongue which indicates the anesthesia of lingual nerve and objective there will not be any pain during the procedure so what are the precautions should be taken while giving INB that is do not deposit local anesthetic if bone is not contacted because the needle tip might be resting on the parotid gland and by accidentally if we deposit solution on the parotid gland the nerve branch that is a facial nerve is there and it might cause facial paralysis temporary facial paralysis and avoid pain by not contacting bone too forcefully so our ultimate aim is to get a bone resistance but we should not cause pain by contacting bone too forcefully and now let's see the problems associated with or the complication associated with INB so the most common complications involved in INB is facial nerve paralysis trismus and hematoma so we discussed how the transient facial nerve paralysis happening when the bone resistance is not obtained and our needle tip is at parotid gland level and we are depositing the solution so parotid gland has facial nerve branches so this solution will anesthetize facial nerve so the facial nerve involving the facial muscles will not work properly on one side it will create temporary facial nerve paralysis so the symptoms of this facial nerve paralysis is inability to close the lower eyelid and dropping of upper lip on the affected side so as you see the picture here so inability to close the lower eyelid and drooping of upper lip on the affected side so that is facial nerve paralysis but it is a transient effect the patient will be okay after once the effect of this anesthesia is gone so second one is trismus that is a muscle soreness or limited movement so a slight degree of soreness when opening the mandible is very common associated with INB and sometimes more severe soreness will be there if the injection technique is not proper then hematoma which is her swelling of tissues on the medial side of the mandibular ramus after deposition of the anesthetic solution so these are the most common complications associated with INB facial nerve paralysis trismus and hematoma so that is all about inferior alginine which is a very commonly asked question you need to draw the proper diagram the insertion point and the boundaries the target area and the terugam mandibular the horizontal line and vertical line the intersection point how the needle should be inserted all this you need to draw and explain okay so hope you understood this inferior alginine block technique so i'll come up with a new topic in oral surgery thank you