Topical Anesthetics PDF

TOPICAL ANESTHETIC S Purpose  Provide temporary numbness to sensory nerve endings of surface mucosa for short period of time  Do not affect sensory nerve endings to tooth Purpose (continued)  Depth of anesthesia is related to amount of absorption of drug.  Absorption varies wit...

TOPICAL ANESTHETIC S Purpose  Provide temporary numbness to sensory nerve endings of surface mucosa for short period of time  Do not affect sensory nerve endings to tooth Purpose (continued)  Depth of anesthesia is related to amount of absorption of drug.  Absorption varies with thickness of epithelial tissue & degree of keratinization  Vestibular tissues absorb quickly  Attached gingiva, buccal mucosa absorb slowly  Skin, lips & palatal mucosa are highly resistant Uses  Prior to injection for local anesthesia  Prevention of gagging during x-ray exposure & taking of impressions  During instrumentation for probing, scaling  Suture removal  Seating crowns  Placing matrix bands  Pain relief from localized diseased areas  Oral ulcers, wounds or injuries Characteristics of a good topical anesthetic  Produce effective lasting anesthesia  Is stable in the form it is used  Anesthetizing agent easily released from preparation when applied  Non-irritating to tissues  Doesn’t induce hypersensitivity & is not toxic in concentration required for anesthesia Characteristics (continued)  Doesn’tdelay healing  Can be washed off with water Forms of topical anesthetic  Ointments  Gels  Liquids  Sprays  Oralrinses  Patches Components of anesthetic  Esters  First local anesthetic used was cocaine  Had many adverse side effects  Tried to retain properties of cocaine while eliminating side effects  Result was esters  Have a tendency to produce allergic reactions  Less effective & shorter acting than amides  Used more for topical vs local anesthetics Components of anesthetic  Amides  More recently developed  Have different chemical structure  Relatively free of allergic reactions  Have potential for toxicity or drug overdose  Cause vasodilation of blood vessels Types of anesthetics  Benzocaine (ester)  Most widely used topical agent  Available in liquid, gel, ointment & spray  Not readily absorbed into circulation  Toxicity potential is minimal  May cause allergic reaction with prolonged or repeated application  30 second onset, optimum depth & intensity achieved in several minutes  1-2 min application time recommended, du  Duration is 5-15 minutes Types of anesthetics  Tetracaine Hydrochloride (ester)  Rapid absorption & high toxicity  Used as part of a combination of drugs in liquid, gel or spray  2 min. onset, 20-60 min. duration  Should not be used over a large area Types of anesthetics  Lidocaine (amide)  Allergy is rare, toxicity is unlikely  Only amide used as topical anesthetic  1-2 min. onset, optimum effectiveness is 5 min. Recommended to wait at least 3 min. before injection  Duration is 15 min.  Available in spray, ointment & transoral patch Types of anesthestics  Lidocaine Transoral patch  Bioadhesive patch that improves duration of contact between topical & tissue  Profound soft tissue anesthesia plus minimal pulpal anesthesia in some cases  2 ½ -5 min. onset; maximum effectiveness after 15 min.  45 min. duration after 15 min. application Topical anesthesia vs anesthesia by injection  Topical  Loss of sensation to gingiva  Short duration  Slower rate of onset (3-5 min.)  5 min. optimum before beginning injection or other work  Injection  Loss of sensation to teeth & gingiva  Longer duration, rapid onset Adverse Reactions  Allergic response  Ester type drugs have a greater tendency to produce allergic reactions than amides  Symptoms: range from mild localized erythema, swelling, ulcerations, difficulty swallowing, difficulty breathing or itching to life threatening anaphylaxis Adverse Reactions  Overdose  Toxic reaction when a large quantity of agent is spread over a large area & rapid absorption through mucuous membrane occurs resulting in immediate elevation of anesthetic blood level  Overdose more common with local anesthetics  Patient becomes more talkative, apprehensive & excited with higher pulse & BP Technique  Gather ointment on end of cotton tipped applicator & place on 2X2 gauze  Use sterile gauze to dry injection site  Remove gauze & position applicator directly on injection site  Repeat if more than 1 injection site is to be given  Use new cotton tipped applicator for each site Technique (cont.)  Leave cotton tipped applicator in place for time recommended by manufacturer; a minimum of 1 min. Injection Sites ????  Treating:  Amalgam restorations # 29, 30, 31  Extracting # 1 (1 primary, 1 secondary)  Crown prep on #18 (1 primary; 2 secondary)  Extracting # 8 (1 primary, 1 secondary)  Apicoectomy on #6  MOD Composite on #3 Mandibular nerve block (Inferior alveolar nerve block) Long buccal Mental nerve block Greater palatine injection Nasopalatine Injection