Local Anesthesia - Presentation PDF

Local Anesthesia Dr.Lama M. Al-Sabe’ BA, M.Sc Paed Dent  Introduction. ⚫It is generally agreed that one of the most important aspects of child behavior guidance is the control of pain. ⚫If children experience pain during restorative or surgical procedures, thei...

Local Anesthesia Dr.Lama M. Al-Sabe’ BA, M.Sc Paed Dent  Introduction. ⚫It is generally agreed that one of the most important aspects of child behavior guidance is the control of pain. ⚫If children experience pain during restorative or surgical procedures, their future as dental patients may be damaged.  Topical Anesthesia ⚫Reduce the slight discomfort associated with the insertion of the needle into the mucosal membrane (2-3 mm in depth). ⚫Topical anesthetics are available in gel, liquid, ointment, and pressurized spray forms. ⚫The pleasant-tasting and quick-acting liquid, gel, or ointment preparations seem to be preferred by most dentists. ⚫Applied to the oral mucous membranes with a cotton-tipped applicator.  Topical Anesthesia ⚫A variety of anesthetic agents have been used in topical anesthetic preparations, including ethyl aminobenzoate, butacaine sulfate, cocaine, dyclonine, lidocaine, and tetracaine. ⚫Ethyl aminobenzoate (benzocaine) liquid, ointment, or gel preparations are probably best suited for topical anesthesia in dentistry; ⚫Rapid onset. ⚫Longer duration of action. ⚫Not known to produce systemic toxicity as oral topical anesthetics, but a few localized allergic reactions have been reported from prolonged or repeated use. ⚫The best result to use the gel on dry mucosa for at least 2 min.  Topical Anesthesia ⚫Benzocaine is manufactured in concentrations up to 20%; lidocaine is available as a solution or ointment up to 5% and as a spray up to a 10% concentration. ⚫Topical lidocaine has an exceptionally low incidence of allergic reactions but is absorbed systemically and can combine with an injected amide local anesthetic to increase the risk of overdose. ⚫So, systemic absorption of the drugs in topical anesthetics must be considered when calculating the total amount of anesthetic administered.  Topical Anesthesia ⚫The mucosa at the site of the intended needle insertion is dried with gauze, and a small amount of the topical anesthetic agent is applied to the tissue with a cotton swab. ⚫The time required for the topical anesthetic to reach its full effectiveness may vary from 30 seconds to 5 minutes. ⚫During the application, the dentist should prepare the child for the injection. It should not necessarily be a detailed description but simply an indication that the tooth is going to be put to sleep so that the treatment can proceed without discomfort.  Selection of Syringes and Needles ⚫ADA has established standards for aspirating syringes for use in the administration of LA. ⚫Needle selection should allow for profound local anesthesia and adequate aspiration. ⚫Larger gauge needles less deflection + more reliable aspiration. ⚫The depth of insertion varies not only by injection technique, but also by the age and size of the patient. ⚫Lengths: long (32 mm), short (20 mm), and ultrashort (10 mm).  Selection of Syringes and Needles ⚫Needle gauges range from size 23 to 30. ⚫Needle breakage is a rare occurrence. ⚫Causes of needle breakage are: ⚫weakening the needle due to bending it before insertion into the soft tissues (the primary cause). ⚫Patient movement after the needle is already inserted.  Selection of Syringes and Needles Recommendations (AAPD): ⚫For the administration of LA, dentists should select aspirating syringes that meet ADA standards. ⚫Short needles may be used for any injection in which the thickness of soft tissue is < 20mm. A long needle may be used for a deeper injection into soft tissue. ⚫Any 23- through 30-gauge needle may be used for intraoral injections, since blood can be aspirated through all of them. Aspiration can be more difficult, however, when smaller gauge needles are used. ⚫An extra-short, 30-gauge is appropriate for infiltration injections. ⚫Needles should not be bent if they are to be inserted into soft tissue to a depth of >5 mm or inserted to their hub for injections to avoid needle breakage.  Thank You Any Question ?? Local Anesthesia Part 2 Dr.Lama M. Al-Sabe’ BA, M.Sc Paed Dent  General Considerations for Local Anesthesia Mechanism of action: ⚫The evidence supports that local anesthetic block sodium cannels through the attachment to sodium channels and configurable changes of sodium receptors of neural membranes.  General Considerations for Local Anesthesia ⚫The efficacy of local anesthesia depends on the concentration of local anesthetic on a segment of the nerve any excess is wasteful and potentially dangerous. ⚫Failure to obtain anesthesia is most likely due to operator error in depositing the solution sufficiently close to the nerve or to anatomic aberration (e.g. accessory innervation).  General Considerations for Local Anesthesia Local infection and inflammation: ⚫They can modify the normal local physiology of tissue by causing the release of neuroactive substance( e.g. histamine, leukotrienes, kinins, and prostaglandins) and by lowering the pH. ⚫These changes reduce the lipid solubility of the anesthetic and interfere with its ability to penetrate the nervous tissue.  General Considerations for Local Anesthesia ⚫Blocking the nerve at a more proximal site distant from the infected area may be a viable alternative. ⚫This may include the deposition of local anesthesia in intraligamental or intrapulpal sites. ⚫Antibiotic administration may reduce the extent of infection and permit definitive treatment under local anesthesia that would otherwise be impossible.  General Considerations for Local Anesthesia ⚫Local Anesthesia may be obtained anatomically by one of the three means: 1. The nerve block: the placement of anesthetic on or near a main trunk. This result in a wide area of tissue anesthesia. 2. The field block: the placement of anesthetic on secondary branches of a main nerve. 3. Local infiltration: the deposition of the anesthetic on terminal branches of a nerve. Adequate diffusion of local anesthetic from local infiltration readily occurs in children because their bones are less dense than those of adults. Classification of Local Anesthetics  Injectable Local Anesthetic Agents ⚫Absolute contraindications for LA include a documented LA allergy. ⚫True allergy to an amide is exceedingly rare. Allergy to one amide does not rule out the use of another amide, but allergy to one ester rules out use of another ester. ⚫A bisulfate preservative is used in LA containing epinephrine. For patients having an allergy to bisulfates, use of LA without a vasoconstrictor is indicated. ⚫LA without vasoconstrictors should be used with caution due to rapid systemic absorption which may result in overdose.  Injectable Local Anesthetic Agents ⚫A long-acting LA (i.e. bupivacaine) is not recommended for the child or the physically or mentally disabled patient prolonged effect increases the risk of soft tissue injury. ⚫Epinephrine decreases bleeding in the area of injection. ⚫Epinephrine concentrations of 1:50,000 may be indicated for infiltration in small doses into a surgical site to achieve hemostasis but are not indicated in children to control pain. ⚫LA that contain vasopressors help reduce toxicity by slowing the rate of absorption of the anesthetic and/or vasopressor into the cardiovascular system. ⚫A vasopressor-containing LA should be used when treatment extends to 2 or more quadrants in a single visit.  Documentation of local anesthesia ⚫The patient record is an essential component of the delivery of competent and quality oral health care. ⚫Following each appointment, an entry is made in the record that accurately and objectively summarizes that visit. ⚫Appropriate documentation includes specific information relative to the administration of local anesthesia.  Documentation of Local Anesthesia Recommendations: 1.Documentation must include the type and dosage of local anesthetic. Dosage of vasoconstrictors, if any, must be noted. (For example, 34 mg lido with 0.017 mg epi or 34 mg lido with 1:100,000 epi). 2.Documentation may include the type of injection(s) given (e.g. infiltration, block, intraosseous), needle selection, and patient’s reaction to the injection. 3.If the local anesthetic was administered in conjunction with sedative drugs, the doses of all agents must be noted on a time-based record. 4.In patients for whom the maximum dosage of local anesthetic may be a concern, the weight should be documented preoperatively. 5.Documentation should include that post-injection instructions were reviewed with the patient and parent.  Thank You Any Question ?? Local Anesthesia Part 3 Dr.Lama M. Al-Sabe’ BA, M.Sc Paed Dent  Operator Technique ⚫Communication in language the child can understand; e.g. the tooth will be going to sleep after a little pinch. ⚫The dentist should not deny that the injection might hurt because this denial may lose the trust the dentist should minimize but not reinforce the child’s anxieties and fears about the pinch.  Operator Technique ⚫The discomfort associated with the injection may be lessened by counterirritation, distraction and a slow rate of administration. ⚫Counterirritation: is the application of vibratory stimuli (e.g. rapid displacement of loose alveolar tissue) or of moderate pressure (e.g. with a cotton-tipped applicator) at the area adjacent to the site of injection. ⚫These stimuli have a physical and psychological basis for modifying noxious input. ⚫The deposition of a single carpule should take at least 1 minute rapid injections tend to be more painful because of rapid tissue expansion.  Operator Technique ⚫The role of the dental assistant is important during transfer of the syringe and in an anticipation of patient movement. ⚫Once tissue penetration by the needle has occurred, the needle should not be retracted in response to the child’s reaction. Otherwise, the child’s behavior may deteriorate significantly if he/she anticipates reinjection. ⚫Use of finger rests is strongly advocated.  Local Anesthetic Complications Toxicity (overdose) ⚫Most adverse drug reactions develop either during the injection or within 5 to 10 minutes. ⚫Overdose of LA can result from high blood levels caused by a single inadvertent intravascular injection or repeated injections. ⚫LA causes a biphasic reaction (eg, excitation followed by depression)in the central nervous system (CNS).  Local Anesthetic Complications Toxicity (overdose) ⚫Early subjective indications of toxicity involve the CNS and include dizziness, anxiety, and confusion. ⚫This may be followed by diplopia, tinnitis, drowsiness, and circumoral numbness or tingling. ⚫Objective signs may include muscle twitching, tremors, talkativeness, slowed speech, and shivering, followed by overt seizure activity. Unconsciousness and respiratory arrest may occur.  Local Anesthetic Complications Toxicity (overdose) ⚫The cardiovascular system (CVS) response to LA toxicity also is biphasic. ⚫The CVS is more resistant to LA than the CNS. ⚫Initially, during CVS stimulation, heart rate and blood pressure may increase. ⚫As plasma levels of the anesthetic increase, vasodilatation occurs followed by depression of the myocardium with subsequent fall in blood pressure. Bradycardia and cardiac arrest may follow. ⚫The cardiodepressant effects of LA are not seen until there is a significantly elevated LA blood level.  Local Anesthetic Complications Toxicity (overdose) ⚫LA toxicity can be prevented by: ⚫Careful injection technique. ⚫Watchful observation of the patient. ⚫Knowledge of the maximum dosage based on weight.  Local Anesthetic Complications Toxicity (overdose) ⚫Aspirate before every injection and inject slowly. ⚫After the injection, the doctor, hygienist, or assistant should remain with the patient while the anesthetic begins to take effect. ⚫Early recognition of a toxic response is critical for effective management. When signs or symptoms of toxicity are noted, administration of LA should be discontinued. ⚫Additional emergency management is based on the severity of the reaction. Table 2. Maximum Recommended Dosage of Local Anesthetic Agents Maximum Dosage Maximum total Anesthetic mg/carpule mg/kg mg/lb dosage Lidocaine 2% 1:000,000 epi 4.4 2.0 300mg 36mg Mepivacaine 3% plain 4.4 2.0 300mg 54mg Articaine 4% 1:100,000 epi 7.0 3.2 500mg 72mg Prilocaine 4% plain 6.0 2.7 400mg 72mg Bupivacaine 0.5% 1:200,000 1.3 0.6 90 mg 9mg epi Adapted from Stanley Malamed, Handbook of Local Anesthesia, Fifth Edition * 2% = 20 mg/ml × 1.8 ml/carpule = 36 (mg carpule)  Local Anesthetic Complications Calculation of the Maximum recommended dose: ⚫To calculate the maximum recommended dose, the weight of the patient must be known. ⚫A maximum dose of 4.4 mg/kg of lidocaine can be used. In a 10 kg patient, this means that: 4.4 mg/kg x 10 kg = 44 mg total can be used. ⚫As 2% Lidocaine contains 36 mg of Lidocaine per carpule, this means that: 44 / 36 = 1.2 carpules (the maximum number of carpules given for a child weight 10 kg).  Local Anesthetic Complications Management of overdose ⚫It depends on the presenting signs & symptoms: ⚫Mild reactions: patient reassurance and, if necessary, termination of the planned treatment. ⚫Severe reactions: oxygen supplementation, ventilatory support, and possible hospitalization.  Local Anesthetic Complications Allergy to local anesthesia ⚫Allergic reactions are not dose dependant but are due to the patient’s heightened capacity to react to even a small dose. ⚫Allergies can manifest in a variety of ways, some of which include urticaria, dermatitis, angioedema, fever, photosensitivity, or anaphylaxis. ⚫Emergency management is dependent on the rate and severity of the reaction.  Local Anesthetic Complications Paresthesia ⚫Paresthesia is persistent anesthesia beyond the expected duration. ⚫Trauma to the nerve can produce paresthesia and, among other etiologies, trauma can be caused by the needle during the injection. ⚫The patient may experience an “electric shock” in the involved nerve distribution area. ⚫Paresthesia also can be caused by hemorrhage in or around the nerve.  Local Anesthetic Complications Paresthesia ⚫Risk of permanent paresthesia is 1:1,200,000 for 0.5%, 2%, and 3% local anesthetics and 1:500,000 for 4% local anesthetics. ⚫Reports of paresthesia are more common with articaine and prilocaine than expected from their frequency of use. ⚫Paresthesia unrelated to surgery most often involves the tongue, followed by the lip, and is more common with 4% solutions of articaine or prilocaine. ⚫Most cases resolve in 8 weeks.  Local Anesthetic Complications Postoperative self–induced soft tissue injury ⚫Most lip- and cheek-biting lesions of this nature are self-limiting and heal without complications, although bleeding and infection possibly may result. ⚫The use of bilateral mand blocks does not increase the risk of soft tissue trauma when compared to unilateral mand blocks or ipsilateral max infiltration. ⚫The frequency of soft tissue trauma was much higher than expected when only 1 side was anesthetized. ⚫Using mand infiltration vs blocks is not of great value in prevention of these injuries, since the duration of soft tissue anesthesia may not be reduced significantly. In addition, for some procedures, infiltration is not as effective as the mand block.  Local Anesthetic Complications Postoperative soft tissue injury ⚫Caregivers responsible for postoperative supervision should be given a realistic time for duration of numbness and informed of the possibility of soft tissue trauma. ⚫Visual examples may help stress the importance of observation during the period of numbness. ⚫For all LA, the duration of soft tissue anesthesia is greater than dentinal or osseous anesthesia. ⚫There is no research demonstrating a relationship between reduction in soft tissue trauma and the use of shorter acting local anesthetics.  Thank You Any Question ?? Local Anesthesia Part 4 Dr.Lama M. Al-Sabe’ BA, M.Sc Paed Dent  Local Anesthesia by Conventional Injection  LA of Mandibular Teeth & Soft Tissue Inferior Alveolar Nerve Block ⚫The inferior alveolar nerve innervates the mand prim and perm teeth. ⚫Enters the mand foramen on the ling aspect of the mand. ⚫The position of the foramen changes by remodeling more superiorly from the occlusal plane as the child matures into adulthood. ⚫During the period of primary dentition 🡪 it is at or slightly above the occlusal plane. ⚫In adults 🡪 it averages 7mm above the occlusal plane. ⚫It is approximately midway between the ant and post borders of the ramus of the mand.  LA of Mandibular Teeth & Soft Tissue Inferior Alveolar Nerve Block ⚫The child is requested to open widely (mouth props may aid). ⚫The ball of the thumb is positioned in the coronoid notch of the ant border of the ramus, and the fingers on the post border of the ramus. ⚫The needle is inserted btw the internal oblique ridge & the pterygomand raphe. ⚫The barrel of the syringe overlies the D & E on the opposite side parallel to the occlusal membrane. ⚫If unsuccessful 🡪 repeat on a level higher than the previous one.  LA of Mandibular Teeth & Soft Tissue Inferior Alveolar Nerve Block ⚫The depth of insertion averages about 15 mm but varies with the size of the mand and its changing proportions depending on the age of the patient. ⚫Approximately 1 ml of the solution should be deposited around the infalveolar nerve.  LA of Mandibular Teeth & Soft Tissue Lingual Nerve Block ⚫If small amounts of anesthetic are injected during insertion and withdrawal of the needle for the inferior alveolar nerve block, the lingual nerve will invariably be anesthetized as well.  LA of Mandibular Teeth & Soft Tissue Long Buccal Nerve Block ⚫For the removal of mand molars or sometimes for the placement of a rubber dam clamp on these teeth, it is necessary to anesthetize the long buccal nerve. ⚫A small quantity of the solution may be deposited in the mucobuccal fold at a point distal and buccal to the indicated tooth. ⚫All facial mand ging tissue on the side that has been injected will be anesthetized for operative procedures, with the possible exception of the tissue facial to the central and lateral incisors, which may receive innervation from overlapping nerve fibers from the opposite side.  LA of Mandibular Teeth & Soft Tissue Infiltration Anesthesia for Mandibular Primary Molars ⚫The use of buccal infiltration anaesthesia will often produce pulpal anaesthesia of the prim teeth; however, it is usually unreliable when operating on the perm dentition with the exception of the lower incisor teeth.  LA of Mandibular Teeth & Soft Tissue Infiltration Anesthesia ⚫Depending on many reports, one may infer that mand block anesthesia produces more profound anesthesia of mand prim molars, but infiltration may produce adequate anesthesia in mand prim molars for most restorative procedures 🡪 mand infiltration technique was less effective than mand block for extraction and pulpotomy. ⚫So, the most dependable form of anaesthesia in the posterior mand is inferior alveolar nerve block anaesthesia.  LA of Mandibular Teeth & Soft Tissue Infiltration anesthesia for mand incisors ⚫The terminal ends of the inf alveolar nerves cross over the mandibular midline & provide conjoined innervation 🡪 Single inf alveolar nerve block may not be adequate for operative or surgical procedures, even on the side of the block anesthesia. ⚫The labial cortical bone overlying the mand incisors is usually thin enough for supraperiosteal anesthesia techniques to be effective.  LA of Maxillary Teeth & Soft Tissue ⚫Traditionally, dentists have been taught that the middle superior alveolar nerve supplies the max prim molars, the premolars, and the mesiobuccal root of the 1st perm molar. ⚫There is no doubt that the middle superior alveolar nerve is at least partially responsible for the innervation of these teeth. ⚫Jorgensen and Hayden have demonstrated: ⚫Plexus formation of the middle and posterior superior alveolar nerves in the prim molar area on child cadaver dissections. ⚫Max bone thickness approaching 1 cm overlying the buccal roots of the first permanent and second primary molars in the skulls of children.  LA of Maxillary Teeth & Soft Tissue ⚫The bone overlying the 1st prim molar is thin, and this tooth can be adequately anesthetized by injection of anesthetic solution opposite the apices of the roots. ⚫The thick zygomatic process overlies the buccal roots of the 2nd prim and 1st perm molars in the prim and early mixed dentition. ⚫This thickness of bone renders the supraperiosteal (infiltration) injection at the apices of the roots of the 2nd prim molar much less effective; the injection should be supplemented with a second injection superior to the max tuberosity area to block the post sup alveolar nerve. ⚫This supplemental injection helps compensate for the additional bone thickness and the posterior middle superior alveolar nerve plexus.  LA of Maxillary Teeth & Soft Tissue ⚫Because of the horizontal and vertical growth of the maxilla that has occurred by the time the premolars erupt, the buccal cortical bone overlying their roots is thin enough to permit good anesthesia. ⚫So, to anesthetize the max 1st or 2nd premolar, a single injection is made at the mucobuccal fold to allow the solution to be deposited slightly above the apex of the tooth. ⚫The injection should be made slowly, and the solution should be deposited close to the bone (for all infiltration and block anesthesia techniques in dentistry).  LA of Maxillary Teeth & Soft Tissue ⚫Before operative procedures for max prim molars and max premolars, buccal infiltration anesthesia for the buccal tissues should be performed. ⚫If the rubber dam clamp impinges on the palatal tissue, injection of a drop or two of the anesthetic solution into the free marginal tissue lingual to the clamped tooth will alleviate the discomfort and will be less painful than the true greater (anterior) palatine injection. ⚫The greater palatine injection is indicated if max prim molars or premolars are to be extracted or if palatal tissue surgery is planned.  LA of Maxillary Teeth & Soft Tissue Anesthetization of the palatal tissue ⚫Anesthesia of the palatal tissues can be one of the most painful procedures performed in dentistry. ⚫One of the methods for achieving profound anesthesia with minimal pain in the palatal and lingual aspects is interdental (interpapillary) infiltration.  LA of Maxillary Teeth & Soft Tissue Interdental (interpapillary) infiltration ⚫After buccal infiltration slow injection of the anesthetic solution as the needle is penetrating the papilla. ⚫The interdental infiltration allows diffusion of the anesthetic to the palatal aspect via the craterlike area of the interproximal oral mucosa joining the lingual and buccal interdental papillae, known as the col. ⚫Blanching of the area is indicative of sufficient anesthesia of the superficial soft tissues; however, additional palatal infiltration may be given as needed.  Thank You Any Question ?? Local Anesthesia Part 5 Dr.Lama M. Al-Sabe’ BA, M.Sc Paed Dent  LA of Maxillary Teeth & Soft Tissue Nasopalatine nerve block ⚫Blocking the nasopalatine nerve will anesthetize the palatal tissues of the six anterior teeth. ⚫It is painful and is not routinely used before operative procedures. ⚫The needle is inserted alongside the incisive papilla, just posterior to the central incisors. It is directed upward into the incisive canal. The discomfort associated with the injection can be reduced by deposition of the anesthetic solution in advance of the needle. ⚫When anesthesia of the canine area is required, it may be necessary to inject a small amount of anesthetic solution into the gingival tissue adjacent to the lingual aspect of the canine to anesthetize overlapping branches of the greater palatine nerve. Nasopalatine nerve block  LA of Maxillary Teeth & Soft Tissue Greater palatine injection ⚫It will anesthetize the mucoperiosteum of the palate from the tuberosity to the canine region and from the median line to the gingival crest on the injected side. ⚫This injection is used with the middle or posterior alveolar nerve block before surgical procedures. ⚫The innervation of the soft tissues of the posterior two thirds of the palate is derived from the greater and lesser palatine nerves.  LA of Maxillary Teeth & Soft Tissue ⚫Before the injection is made, it is helpful to bisect an imaginary line drawn from the gingival border of the most posterior molar that has erupted to the midline. ⚫Approaching from the opposite side of the mouth, the dentist makes the injection along this imaginary line and distal to the last tooth. ⚫In the child in whom only the prim dentition has erupted, the injection should be made approximately 10 mm posterior to the distal surface of the 2nd prim molar. ⚫It is not necessary to enter the greater palatine foramen. A few drops of the solution should be injected slowly at the point where the nerve emerges from the foramen.  Supplemental Injection Techniques Infraorbital nerve block and mental nerve block ⚫The infraorbital block technique is preferred when: ⚫Impacted teeth (especially canines or first premolars) or large cysts are to be removed. ⚫Moderate inflammation or infection contraindicates use of the infiltration injection site. ⚫Longer duration or a greater area of anesthesia is needed.  Supplemental Injection Techniques The mental nerve block ⚫It leaves the patient with essentially the same feelings of numbness as the inferior alveolar nerve block. ⚫Blocking the mental nerve anesthetizes all mandibular teeth in the quadrant except the perm molars. ⚫It is possible to perform routine operative procedures on all prim teeth without discomfort to the patient. However, inferior alveolar nerve block should be favored unless there is a specific contraindication to its use at the inferior alveolar nerve injection site. ⚫The mental nerve block is no more comfortable for the patient, and the technique puts the syringe in clear view of the patient, whereas the inferior alveolar nerve block may be performed with the syringe out of the child's direct vision.  Supplemental Injection Techniques The periodontal ligament injection (intraligamentary) ⚫an adjunctive method of obtaining more complete anesthesia when supraperiosteal or block techniques failed to provide adequate anesthesia. This technique has also gained credibility as a good method of obtaining primary anesthesia for one or two teeth.  Supplemental Injection Techniques The periodontal ligament injection (intraligamentary) ⚫The technique is simple, requires only small quantities of anesthetic solution, and produces anesthesia almost instantly. ⚫The needle is placed in the gingival sulcus, usually on the mesial surface, and advanced along the root surface until resistance is met. Then approximately 0.2 ml of anesthetic is deposited into the periodontal ligament. ⚫For multirooted teeth, injections are made both mesially and distally. Considerable pressure is necessary to express the anesthetic solution.  Supplemental Injection Techniques The periodontal ligament injection (intraligamentary) ⚫A conventional dental syringe may be used for this technique. However, the great pressure required to express the anesthetic makes it desirable to use a syringe with a closed barrel to offer protection in the unlikely event that the anesthetic cartridge should break. ⚫Some syringes are equipped with a metal or Teflon sleeve that encloses the cartridge and provides the necessary protection should breakage occur.  Supplemental Injection Techniques The periodontal ligament injection (intraligamentary) ⚫Syringes designed specifically for the periodontal ligament injection technique have been developed. The Peri-Press, is designed with a lever-action “ trigger" that enables the dentist to deliver the necessary injection pressure conveniently. ⚫The Peri-Press syringe has a solid metal barrel and is calibrated to deliver 0.14 ml of anesthetic solution each time the trigger is completely activated.  Alternative Anesthesia System The Wand (Computer controlled system) ⚫Adv: ⚫Thin. ⚫Wand- like syringe and held like a pen (less threatening). ⚫A foot control delivers the anesthetic at a relatively slow rate and constant pressure by a microprocessor-controlled regulator.  Thank You Any Question ??