LOCAL ANESTHESIA in field of dentistryPPT(S1).pptx

role of LA, INDICATIONS, COMPLICATIONS AND MANAGEMENT

1. Local anesthesia Painless Dentistry : A Local Anesthesia Success Story Dr.Sreeja  JR -1 9-11-2023

2. Contents Introduction Historical background Definition Ideal properties Mechanism of action of LA Classifications of LA Dissociation of LA

3. Composition of local anesthesia solution Pharmacokinetics Local and systemic complications Preoperative assessment Universal safety guidelines Recent advances Conclusion References

4. INTRODUCTION Dentistry before the invention of local anesthetics was often a painful and challenging experience. Various methods and substances were used in an attempt to alleviate pain during medical and dental procedures. Some of the methods and substances used for pain relief before local anesthetics include: Alcohol Opium and other opiates

5. 3. Herbal remedies: extracts from plants like mandrake and belladonna 4. Ice and cold 5. Hypnosis and mesmerism 6. Forced immobilization 7. Distraction techniques

6. The availability of general anesthesia significantly improved the patient experience for dental procedures. Dentists and oral surgeons could then perform dental extractions, oral surgeries and other procedures while the patient was under general anesthesia. However , the use of general anesthesia carries its own set of risks and considerations.

7. The Journey of Local Anesthesia Cocaine : First local anesthetic agent used in dentistry. Carl Koller , an ophthalmologist, discovered anesthetic properties of cocaine. In early 1900s , novocaine(procaine) was introduced. It was less toxic and had fewer side effects than cocaine. Lidocaine , was discovered by Nils Lofgren in 1943. It had reduced toxicity and relatively low risk of allergic reactions. Articaine, introduced in 1970s,with rapid onset and effectiveness.

8. What is Local anesthesia? Local anesthesia is defined as a reversible loss of sensation in a circumscribed area of body caused by depression of excitation in nerve endings or an inhibition of conduction process in peripheral nerves. Loss of sensation without inducing loss of consciousness .

9. Ideal properties of local anesthesia It should not be irritating to tissues. It should not cause any permanent alteration of nerve structure. Its systemic toxicity should be low . Time of onset of local anesthesia should be short. It should be effective. The duration of action should be long enough to permit completion of procedure.

10. Dissociation of local anesthetics Local anesthetics are available as weak bases (usually hydrochloride) for clinical use. In solution , it exists simultaneously as uncharged molecules (RN),also called Base , and as positively charged molecules(RNH+), called the cation . RNH+ RN + H+

11. In case of low PH , the equilibrium shifts to the left. RNH+ > RN + H+ In case oh higher PH , the equilibrium shifts towards the right . RNH+ < RN + H+ The relative proportion of ionic forms also depends on the dissociation constant( pKa ).

12. Mechanism of action of Local anesthetics Local anesthetic agent achieves interference with excitation process in a nerve membrane in one of the following ways, Altering the basic resting potential of nerve membrane Altering the threshold potential Decreasing the rate of depolarization Prolonging the rate of repolarization.

13. Classifications of Local anesthetics Based on source – Natural, Synthetic, Others. Based on mode of application- Injectable, Topical Based on duration of action- Ultra short (<30 min) , Short (45-75min), Medium (90-150min), Long (180min) Based on onset of action – Short , Intermediate, Long

14. Classification of local anesthetics: Esters Amides Esters Esters of Benzoic acid Esters of para amino benzoic acid Butacaine * Chlorprocain Cocaine * Procaine Benzocaine * Propoxycaine Hexylcaine Piperocaine Tetracaine

15. Amides. Quinoline Articaine *centbucridine Bupivacaine Dibucaine Etidocaine Lidocaine Mepivacaine Prilocaine Ropivacaine

16. Composition Commercially prepared local anesthesia consists of:- Local anesthetic agent (Xylocaine, Lignocaine 2%) Blockade of nerve conduction. Vasoconstrictor (Adrenaline 1:80,000) Reducing agent (Sodium meta bisulphite) ( antioxidant) Preservative (Methyl paraben, capryl hydrocuprieno toxin) Fungicide (Thymol) Vehicle (Distilled water, Nacl ) Volume, isotonicity of solution.

17. Vasoconstrictor Decreases blood flow Lower anesthetic blood level Decrease risk of toxicity Increases duration of action Decrease bleeding Max dose of vasoconstrictor ; - Healthy patient : 0.2mg - patient with significant cardiovascular history : 0.04mg .

18. Pharmacokinetics of local anesthetics UPTAKE - oral route - Topical route - Injection METABOLISM - Esters - Amides EXCRETION

19. Oral route Except cocaine, local anesthetics are poorly absorbed from GIT. Most local anesthetics undergo hepatic first pass metabolism. Tocainide hydrochloride an analogue of lidocaine is effective orally.

20. Topical route Local anesthetics are absorbed at different rates after application on mucous membrane. Eutectic mixture of local anesthesia (EMLA) has been developed to provide surface anesthesia for intact skin. (Lidocaine 2.5%+prilocaine 2.5%)

21. Injection The rate of uptake of local anesthetics after injection is related to both vascularity of injection site and vasoactivity of drug. IV administration of local anesthetics provide the most rapid elevation of blood levels.

22. Local complications Needle breakage Prolonged anesthesia or paresthesia Facial nerve paralysis Trismus Soft tissue injury

23. 6) Hematoma 7) Pain on injection 8) Infection 9) Sloughing 10)Edema

24. Management Complications of LA TRISMUS EDEMA PARESTHESIA FACIAL NERVE PARALYSIS FAIL LA HEMATOMA Antihistamine If breathing compromised CPR Corticosteroids Epinephrine Reassurance Eye dressing Contact lens remove Analgesic Heat therapy Rinse warm saline Muscle relaxant Follow up 2months Usually subsided by 2 weeks Prescribed vit B (1,6,12) Ice pack 2-3 mins Reassurance Antibiotic , analgesic Repeat LA If infection increase dose

25. Systemic complications Overdose reactions Allergic reactions – more common with ester based local anesthetics. Most allergies are due to preservatives in pre made local anesthetic solutions. Methyl paraben Sodium bisulphite Meta bisulphite.

26. Clinical manifestations of local anesthetic overdose SIGNS >Low to moderate blood levels: Confusion Talkativeness Apprehension Excitedness Slurred speech

27. Muscular twitching Elevated BP , Heart rate and respiratory rate >Moderate to high blood levels: Generalised tonic clonic seizers followed by Generalised CNS depression Depressed BP , Heart rate and respiratory rate.

28. Symptoms: Headache Auditory disturbances Dizziness Blurred vision Numbness of tongue and perioral tissues Loss of consciousness.

29. COMMON QUESTIONS TO ASK THE PATIENT Allergic to any medications ? Have you ever had a reaction to local anesthesia ? If yes , describe what happened Was treatment given ? If so , what ?

30. PREOPERATIVE ASSESSMENT Data should be documented includes : Baseline vital signs : blood pressure , laboratory values, results of ECG monitoring , any other tests Weight , height and age Current medical problems , past history Current medications Allergy or hypersensitivity Mental status , communication ability

31. DISEASE PRECAUTIONS Cardiovascular disease Use stress reduction protocol Hypertension Minimize vasoconstrictor use Nonselective beta blockers Avoid vasoconstrictors Cardiac dysrhythmia(refractory) Minimize vasoconstrictor use ; Avoid PDL and intraosseous injection Long acting nitrates and vasodilators Watch for decreased anesthetic duration Asthma Stress reduction protocol; minimize vasoconstrictor use Renal disease Reduced dosage ; extend time between Local anesthetic use in different medical conditions

32. UNIVERSAL SAFTEY GUIDELINES FOR ADMINISTRATION OF LA Aspirate carefully before injecting – to reduce the risk of unintentional intravascular injection. Inject slowly ; a maximum rate of 1ml/min or less. Monitor the patient both during and after the injection for unusual reactions. Select the anesthetic agent based upon the duration of anesthesia appropriate for the planned procedure.

33. Use the minimum amount of anesthetic solution - to achieve an adequate level of anesthesia - to keep the patient comfortable throughout the dental procedure.

34. RECENT ADVANCES AND FUTURE TRENDS IN PAIN CONTROL

35. Nanotechnology in local anesthetics Computerized anesthesia delivery systems - WAND - CompuDent Needleless anesthesia Local anesthetic reversal agents - OraVerse Liposomal delivery systems

36. Intraoral lignocaine patch (dentipatch) Topical gels EMLA Personalized medicine and dosage calculators Anesthetic monitoring devices Biodegradable sutures with anesthetics

37. LA OVERDOSE MANAGEMENT

38. RULE OF 25 The rule of 25 , which states that for healthy patients, a dentist can safely use one catridge of anesthetic solution for every 25 pounds of patient weight . 25 pounds = 11.3 kilograms

39. HOT TOOTH

40. CATEGORIES OF DRUGS IN PREGNANCY

41. CONCLUSION Adapting local anesthetic technique can overcome difficulties in soft tissue anesthesia. Local anesthetic doses must be controlled. Local anesthesia remains the backbone of pain control in dentistry. Research has been continued in both medicine and dentistry to seek new and better means of managing pain associated with many surgical treatments. If you can provide a nearly painless surgical procedure without the use of general anesthesia then you have won half of the battle.

42. References Handbook of local anesthesia – Stanley F Malamed, 6 th edition . Local analgesia in dentistry – by d.h.Roberts and j.h.sowray Monehim”s local anesthesia and pain control , Benett

43. THANK YOU