Medical emergencies in the dental clinic

In short

A medical emergency in the dental clinic is any sudden, life-threatening or potentially life-threatening change in a patient's condition occurring before, during or after dental treatment — most often vasovagal syncope, but also hypoglycaemia, angina/myocardial infarction, asthma, anaphylaxis, seizures, local anaesthetic toxicity, airway obstruction and cardiac arrest. Dental patients are at elevated risk because of anxiety, pain, injected vasoconstrictors, supine positioning, an open airway full of instruments, and an increasingly elderly, polypharmacy-taking population. It is examined in BDS Oral Medicine, Oral Surgery, Pharmacology and General Medicine papers, and in university practicals as a BLS/scenario station. In interviews — PG entrance (NEET MDS), hospital and corporate chain clinical rounds (Clove, Apollo White, FMS, Sabka Dentist), and government dental officer selections — drug doses, the BLS sequence and recognition questions are near-certain.

Explained

Prevention: risk assessment before the handpiece

• Prevention is 90% of emergency management. A written medical history with periodic update, recorded vitals, and anxiety control prevent most events.
• ASA physical status classification (American Society of Anesthesiologists) is the standard chairside risk triage:
  • ASA I — healthy; ASA II — mild controlled systemic disease (well-controlled diabetes/hypertension, pregnancy, anxious patient); ASA III — severe disease limiting activity but not incapacitating (angina on exertion, post-MI >6 months, poorly controlled diabetes); ASA IV — incapacitating disease, constant threat to life (unstable angina, MI or CVA within the last 6 months, uncontrolled epilepsy); ASA V — moribund; ASA VI — brain-dead organ donor.
  • Rule of thumb: ASA I–II routine treatment; ASA III treat with modification (short morning appointments, supplemental oxygen, stress reduction, BP/glucose check); ASA IV defer elective care and refer/treat in a hospital setting.
• Baseline vitals: BP, pulse, respiratory rate, SpO₂; capillary glucose for diabetics. Defer elective care if BP ≥180/110 mmHg (recheck after rest), random glucose grossly uncontrolled, or resting SpO₂ <94% in a dyspnoeic patient.
• Stress-reduction protocol: morning appointment, adequate sleep, pre-operative anxiolysis (oral diazepam 5 mg the night before and 1 h prior, if prescribed), profound local anaesthesia, short appointments, nitrous oxide–oxygen where available, post-operative analgesia.
• Drug history red flags: warfarin/DOACs (bleeding), bisphosphonates (MRONJ), steroids (adrenal crisis), beta-blockers (interaction with adrenaline in LA), metformin/insulin (hypoglycaemia if fasting), antihypertensives (postural hypotension), penicillin/NSAID allergy.
• Preparedness: office emergency drug kit and oxygen checked monthly with expiry log, staff BLS-certified and re-trained 6-monthly, mock drills, written emergency numbers, nearest hospital with cath-lab identified.

The universal first response — P-C-A-B-D

• Position (P): stop treatment, remove all instruments and debris from the mouth, place the conscious-but-faint or unconscious patient supine with legs raised 10–15° (Trendelenburg-like). Exceptions: the breathless/orthopnoeic patient (asthma, heart failure, hyperventilation) sits upright; the pregnant patient in the third trimester is placed in left lateral decubitus (to relieve supine hypotensive syndrome from IVC compression).
• C — Circulation: check carotid pulse for not more than 10 seconds; begin chest compressions if absent. (Current BLS places compressions first, hence C-A-B.)
• A — Airway: head-tilt–chin-lift; jaw-thrust if cervical spine injury is suspected. Suction blood, saliva, impression material.
• B — Breathing: look-listen-feel; if not breathing normally, give ventilation with a bag-valve-mask and 100% oxygen.
• D — Definitive care / Drugs / Defibrillation: activate emergency medical services (dial 108, the national ambulance number, or 112), give drug therapy, attach an AED, arrange transfer.
• Always: oxygen (except in hyperventilation, where it worsens alkalosis), monitor vitals every 5 minutes, record times and drugs given in the case sheet.

Basic Life Support (adult, current AHA/ILCOR-based guidance)

1. Ensure scene safety; check responsiveness (shout, tap shoulders).
2. No response and no normal breathing → shout for help, activate EMS (108), ask for the AED.
3. Check carotid pulse ≤10 s; absent → start CPR.
4. Compressions: lower half of the sternum, heel of hand, depth 5–6 cm, rate 100–120/min, full recoil, minimal interruptions (<10 s).
5. Compression : ventilation = 30:2 for one or two untrained-in-advanced-airway rescuers; with an advanced airway, continuous compressions at 100–120/min with 1 breath every 6 s (10/min).
6. Switch compressor every 2 minutes (or every 5 cycles) to limit fatigue.
7. AED as soon as available: attach pads, allow analysis, shock if advised, resume compressions immediately for 2 min before re-analysis.
8. Children (1 year–puberty): depth about 5 cm or one-third of chest depth, 30:2 single rescuer, 15:2 with two rescuers; infants: two fingers or two-thumb encircling technique, depth about 4 cm.
9. The dental chair is a poor CPR surface — lower it fully, make it horizontal, place a board under the back or move the patient to the floor if the chair flexes.
10. Chain of survival: early recognition and call for help → early CPR → early defibrillation → advanced care → post-arrest care.

The common emergencies: recognition and management

• Vasovagal syncope (most common, up to ~50% of dental office emergencies): pre-syncope — pallor, sweating, nausea, light-headedness, bradycardia, hypotension. Management: supine with legs raised, loosen tight clothing, oxygen, cold compress, ammonia inhalant; recovery in seconds to minutes. If unconsciousness lasts beyond ~5 minutes, think of another cause.
• Postural (orthostatic) hypotension: faint on sitting up quickly, especially on antihypertensives, nitrates, or after long supine appointments. Prevent by raising the chair slowly and letting the patient sit for a minute before standing.
• Hyperventilation syndrome (anxiety): rapid deep breathing, perioral and digital tingling, carpopedal spasm, dizziness. Management: sit upright, calm reassurance, slow breathing, rebreathe into cupped hands or a paper bag; withhold oxygen; midazolam only if severe and under supervision.
• Hypoglycaemia (blood glucose <70 mg/dL; symptomatic usually <54 mg/dL): tremor, sweating, confusion, aggression, tachycardia, then seizures/coma. Conscious — 15 g oral glucose (3 teaspoons sugar, glucose gel, 150 mL fruit juice), recheck in 15 min, repeat (the "15-15 rule"). Unconscious — nothing by mouth; 50 mL of 50% dextrose IV (or 100 mL of 25%, i.e. 25 g) or glucagon 1 mg IM, then EMS. Hyperglycaemia/DKA (gradual onset, dehydration, acetone breath, Kussmaul breathing) needs hospital care, not sugar.
• Angina pectoris: retrosternal pressure, radiating to left arm/jaw, relieved by rest. Management: stop work, position comfortably (usually semi-upright), oxygen, glyceryl trinitrate 0.5 mg sublingual tablet or 0.4 mg spray, repeatable at 5-minute intervals up to 3 doses. Withhold nitrates if systolic BP <90 mmHg or if a phosphodiesterase-5 inhibitor (sildenafil within 24 h, tadalafil within 48 h) has been taken — risk of profound hypotension.
• Myocardial infarction: pain >15–20 minutes, not relieved by nitrates, with sweating, nausea, dyspnoea, anxiety, impending doom. Management: call EMS immediately, oxygen if SpO₂ <94%, aspirin 162–325 mg chewed (one 300 mg dispersible tablet chewed in India) unless allergic or actively bleeding, nitrate if BP permits, monitor, be ready for CPR/AED. Elderly and diabetic patients may have "silent" or atypical presentations.
• Acute asthma: wheeze, prolonged expiration, accessory muscle use, inability to complete sentences. Management: sit upright, salbutamol metered-dose inhaler 2 puffs (100 µg each), repeat every 20 minutes up to 3 times, preferably by spacer; oxygen; if no response or life-threatening features (silent chest, cyanosis, exhaustion) give adrenaline 0.3–0.5 mg IM and call EMS. Avoid aspirin/NSAIDs in known aspirin-sensitive asthma.
• Anaphylaxis: onset in minutes — urticaria, flushing, angioedema, stridor, bronchospasm, hypotension, collapse. Adrenaline is the first-line and only life-saving drug: 0.5 mg (0.5 mL of 1:1000) deep IM into the mid-anterolateral thigh in adults, repeatable every 5 minutes; supine with legs raised (upright only if breathless), high-flow oxygen, IV fluids, and adjuncts (chlorpheniramine 10 mg IM/slow IV, hydrocortisone 200 mg IV) which never replace adrenaline. In dentistry the usual triggers are penicillins, NSAIDs, chlorhexidine and latex — not the ester-free amide local anaesthetic itself, true allergy to which is rare.
• Seizures: protect from injury (clear the area, do not restrain, never force anything between the teeth), remove instruments, time the event, position laterally after it ends, oxygen. Status epilepticus (≥5 min or recurrent) → midazolam 10 mg buccal/intranasal or 5–10 mg IM (or IV diazepam where trained) and EMS.
• Stroke: sudden unilateral weakness, facial droop, slurred speech, visual loss. Use FAST (Face, Arm, Speech, Time) or BE-FAST; record time of onset, give nothing by mouth, do not give aspirin (haemorrhage cannot be excluded without imaging), transfer urgently — thrombolysis window is ~4.5 hours.
• Airway obstruction / aspiration or swallowing of an object (burs, endodontic files, crowns, rubber dam clamps, extracted teeth): conscious with effective cough — encourage coughing; ineffective cough — 5 back blows then 5 abdominal thrusts (Heimlich) alternately; unconscious — start CPR. Prevent with rubber dam, floss ligature on small instruments, high-volume suction, throat pack, and chair position. All aspirated/ingested objects need a chest and abdominal radiograph and referral — an aspirated item most often lodges in the right main bronchus (wider, more vertical).
• Adrenal (Addisonian) crisis: in patients on long-term steroids subjected to surgical stress — weakness, hypotension, abdominal pain, confusion. Give hydrocortisone 100–200 mg IV/IM, fluids, EMS.
• Thyroid storm, hypertensive crisis, bleeding and drug overdose/sedation emergencies are managed by stopping the stimulus, supportive ABC care and immediate referral; reversal agents are naloxone 0.4 mg for opioid and flumazenil 0.2 mg for benzodiazepine over-sedation.

Local anaesthetic emergencies

• Maximum safe doses (adult, by body weight — the commonest exam calculation):
  • Lignocaine (lidocaine) plain: 4.4 mg/kg, absolute maximum 300 mg; with adrenaline: 7 mg/kg, absolute maximum 500 mg (some texts quote 4.5 and 7 mg/kg with 300/500 mg ceilings — state the source you use).
  • Articaine 7 mg/kg (max about 500 mg); mepivacaine 2% plain 6.6 mg/kg (max 400 mg); bupivacaine 1.3 mg/kg (max 90 mg) — longer acting, more cardiotoxic.
  • Adrenaline limits: 0.2 mg per appointment in a healthy adult; 0.04 mg in a cardiac-compromised patient (ASA III–IV) — i.e. about 2 cartridges of 1:100,000.
• LA toxicity (overdose) is dose-related and biphasic: early excitation — talkativeness, circumoral numbness, metallic taste, tinnitus, tremor, confusion, then seizures; followed by CNS and cardiovascular depression — respiratory arrest, bradycardia, hypotension, arrest. Management: stop injection, supine, oxygen, ventilate, benzodiazepine for seizures, EMS; in severe cardiotoxicity hospitals use intravenous lipid emulsion.
• Adrenaline reaction: anxiety, palpitations, tremor, headache, rise in BP, short-lived (adrenaline half-life is minutes). Reassure and monitor; distinguish from anaphylaxis (no urticaria, no hypotension) and from true overdose.
• Methaemoglobinaemia: chocolate-brown blood, cyanosis unresponsive to oxygen, SpO₂ stuck around 85%; associated with prilocaine and topical benzocaine, especially in children; treated with methylene blue 1–2 mg/kg IV in hospital.
• Other local complications: needle breakage (do not probe; refer for removal), haematoma after posterior superior alveolar block (pressure, ice then heat after 24 h), facial nerve palsy from intraparotid deposition (transient; protect the eye), trismus, prolonged paraesthesia (notably reported more with 4% solutions).
• Avoid adrenaline-containing LA or limit it in uncontrolled hypertension, recent MI/unstable angina, uncontrolled arrhythmia, uncontrolled hyperthyroidism, phaeochromocytoma, cocaine use, and patients on non-selective beta-blockers or tricyclics (use plain or low-dose and aspirate).

Emergency kit, equipment and Indian regulatory context

• Minimum equipment: portable oxygen cylinder with regulator (capable of 10–15 L/min), bag-valve-mask (adult and paediatric), oropharyngeal airways, high-volume suction with wide-bore tips, Magill forceps, BP apparatus and stethoscope, pulse oximeter, glucometer, disposable syringes/needles, IV cannulae and fluids if trained, AED (strongly recommended; not yet universally mandated in Indian private clinics), spine board, torch, written protocol and EMS numbers.
• Core drugs (critical / level 1): adrenaline 1:1000 ampoules, glyceryl trinitrate sublingual, salbutamol inhaler, oral glucose, aspirin 300 mg dispersible, oxygen, antihistamine (chlorpheniramine), midazolam or diazepam. Secondary (level 2): hydrocortisone, 25% dextrose, atropine, glucagon, naloxone, flumazenil, morphine/pethidine where legally permissible.
• Regulatory and legal: dental practice is regulated under the National Dental Commission Act, 2023, which replaced the Dentists Act, 1948 and the Dental Council of India with the National Dental Commission; ethics, record-keeping and consent standards flow from NDC regulations and from the earlier DCI Dentists (Code of Ethics) Regulations, 2014 — exact superseding regulations are being notified in stages, so cite the Act and the subject rather than a regulation number you are unsure of.
• Clinical Establishments (Registration and Regulation) Act, 2010 (adopted by several States) prescribes minimum standards including emergency provisions; Drugs and Cosmetics Act, 1940 and Rules govern storage and the sale/possession of prescription drugs; schedules and expiry control matter in an inspection.
• Bio-Medical Waste Management Rules, 2016 (as amended) govern disposal of used ampoules, needles and sharps after an emergency; sharps go in the white translucent puncture-proof container, contaminated plastics in red, anatomical/soiled waste in yellow.
• Consent and documentation: informed consent before procedures, contemporaneous notes of the emergency (times, vitals, drugs, route, dose, responders), and a referral note. A dentist acting within training to save life is generally protected as a good-faith act under the Bharatiya Nyaya Sanhita, 2023 provisions on acts done in good faith for a person's benefit (the successors to the old IPC sections) — the practical defence is documentation and staying within competence.
• Insurance: professional indemnity cover is standard practice; an emergency handled without oxygen or a kit is hard to defend before a consumer forum, as dental services fall within the Consumer Protection Act, 2019.

Key points

• Commonest dental emergency — vasovagal syncope; definitive first step is supine position with legs raised.
• P-C-A-B-D — Position, Circulation, Airway, Breathing, Definitive care: the universal sequence for any collapse.
• Compressions — 100–120/min, depth 5–6 cm, 30:2, change rescuer every 2 minutes, chair fully flat.
• ASA classification — I healthy to VI brain-dead; ASA IV elective dental care is deferred.
• Anaphylaxis drug — adrenaline 0.5 mg (0.5 mL of 1:1000) IM mid-anterolateral thigh, repeat in 5 min; antihistamines and steroids are adjuncts only.
• Angina — GTN 0.5 mg sublingual up to 3 doses; contraindicated with sildenafil in 24 h or systolic BP <90.
• MI — pain unrelieved by nitrate, chewed aspirin 300 mg, call 108, be AED-ready.
• Asthma — salbutamol 2 puffs (100 µg each) by inhaler/spacer, patient upright, repeat up to 3 times.
• Hypoglycaemia — 15 g oral glucose if conscious (15-15 rule); 25% dextrose IV or glucagon 1 mg IM if unconscious.
• Seizure — never restrain, never place anything in the mouth; midazolam 10 mg buccal if ≥5 minutes.
• Lignocaine maximum — 4.4 mg/kg plain (300 mg) and 7 mg/kg with adrenaline (500 mg); 1 cartridge of 2% = 1.8 mL = 36 mg.
• Adrenaline in LA — 0.2 mg per visit healthy, 0.04 mg in cardiac patients (about 2 cartridges of 1:100,000).
• LA toxicity — excitation (tinnitus, metallic taste, seizures) then depression (respiratory and cardiac arrest).
• Hyperventilation — the one emergency where oxygen is withheld; rebreathe exhaled air and sit the patient up.
• Pregnancy — third-trimester collapse goes left lateral to relieve supine hypotensive syndrome.
• Aspiration — right main bronchus is the usual site; back blows and abdominal thrusts, then imaging and referral.
• Stroke — FAST, time of onset, nothing by mouth, no aspirin, transfer within the ~4.5-hour thrombolysis window.
• Regulator — the National Dental Commission Act, 2023 replaced the Dentists Act, 1948; ambulance 108, all-emergency 112.

Formulas and examples

Example 1 — Maximum lignocaine for a 60 kg adult, 2% with 1:100,000 adrenaline.

• LA limit: 7 mg/kg × 60 = 420 mg (below the 500 mg ceiling) → permitted 420 mg.
• Per cartridge: 20 mg/mL × 1.8 mL = 36 mg lignocaine; adrenaline = 0.01 mg/mL × 1.8 = 0.018 mg.
• By LA: 420 ÷ 36 = 11.67 → 11 cartridges.
• By adrenaline (healthy, limit 0.2 mg): 0.2 ÷ 0.018 = 11.1 → 11 cartridges. Both limits give 11 cartridges (≈19.8 mL) — in practice far more than any single appointment needs.

Example 2 — The same cartridge in a cardiac (ASA III) patient, adrenaline limit 0.04 mg.

• 0.04 ÷ 0.018 = 2.22 → 2 cartridges only (72 mg lignocaine, 0.036 mg adrenaline).
• The vasoconstrictor, not the anaesthetic, is now the limiting factor — if more anaesthesia is needed, switch to 2% lignocaine plain or 3% mepivacaine plain.

Example 3 — A 20 kg, 6-year-old child, 2% lignocaine with adrenaline.

• Limit 7 mg/kg × 20 = 140 mg (well under 500 mg).
• 140 ÷ 36 = 3.9 → a maximum of 3 cartridges (108 mg), rounding down for safety. Children are the group in which overdose actually happens, because the same cartridge is a far larger dose per kg.

Example 4 — Hypoglycaemia in a fasting diabetic; glucometer reads 48 mg/dL, patient conscious and cooperative.

• Give 15 g carbohydrate: 3 level teaspoons of sugar (≈5 g each) in water, or 150 mL fruit juice.
• Recheck at 15 minutes; suppose it reads 62 mg/dL — still <70, so repeat 15 g and recheck.
• At 15 minutes more it reads 96 mg/dL → give a complex carbohydrate snack, defer the procedure, advise not to skip the next meal or insulin adjustment. Total time 30 minutes, two doses, 30 g glucose.

Example 5 — Oxygen cylinder endurance. A 2 L water-capacity portable cylinder shows 120 bar; anaphylaxis needs 10 L/min.

• Contents ≈ 120 × 2 = 240 L → 240 ÷ 10 = 24 minutes of flow. Enough to bridge to the ambulance, but a second cylinder or a prompt 108 call is essential — this is why a monthly pressure check is in the protocol.

Where it is used

• Private and corporate dental chains (Clove Dental, Apollo White, Sabka Dentist, FMS, Partha): kit-and-oxygen audit, staff BLS certification and mock drills are standard quality checklist items at clinic inspection.
• Dental colleges and hospitals: BLS/ACLS certification is a condition for internship and PG work; emergency scenario stations appear in university practical and viva examinations.
• Government dental officer and ESIC/CGHS/Railways/defence posts: written and interview rounds test ASA grading, drug doses and referral protocols, as the officer is often the only clinician on site.
• Oral and maxillofacial surgery and conscious-sedation practice: pre-operative risk stratification, capnography and pulse oximetry monitoring, reversal agents (naloxone, flumazenil) and airway skills.
• Hospital-based dentistry for medically compromised patients: cardiac, dialysis, transplant and oncology patients treated with physician clearance, steroid cover and modified LA protocols.
• Insurance, accreditation and medico-legal work: NABH-accredited dental facilities and Clinical Establishments Act registration require documented emergency equipment, drugs within expiry and trained staff; consumer-forum cases turn on these records.

Interview questions

• Q: Which is the commonest medical emergency in a dental clinic and how do you manage it? A: Vasovagal syncope; stop treatment, lay the patient supine with legs raised 10–15°, loosen clothing, give oxygen and a cold compress, and monitor — recovery is usually within a minute or two.
• Q: State the maximum dose of 2% lignocaine with 1:100,000 adrenaline for a 50 kg adult in cartridges. A: 7 mg/kg × 50 = 350 mg; one 1.8 mL cartridge has 36 mg, so 9 cartridges — but the adrenaline limit of 0.2 mg (0.018 mg per cartridge) also allows 11, so 9 cartridges is the binding limit.
• Q: How do you distinguish an adrenaline reaction from anaphylaxis? A: Adrenaline reaction raises blood pressure with tremor and palpitations and settles in minutes; anaphylaxis has urticaria, angioedema or stridor with falling blood pressure and needs intramuscular adrenaline.
• Q: Why is adrenaline given intramuscularly in the thigh and not subcutaneously or intravenously in anaphylaxis? A: The vastus lateralis has rich blood flow, giving rapid, reliable absorption; subcutaneous absorption is too slow and intravenous bolus adrenaline risks arrhythmia and hypertensive crisis outside a monitored setting.
• Q: Which emergency is managed without oxygen? A: Hyperventilation syndrome — the problem is respiratory alkalosis from low CO₂, so the patient rebreathes exhaled air rather than receiving oxygen.
• Q: Your patient becomes unresponsive with no pulse in the chair. What are your first three actions? A: Call for help and EMS (108) with the AED, lower the chair flat onto a firm surface, and start chest compressions at 100–120/min, 5–6 cm deep, 30:2 with ventilation.
• Q: A patient on sildenafil develops chest pain. Can you give glyceryl trinitrate? A: No — nitrates within 24 hours of sildenafil (48 hours for tadalafil) can cause profound hypotension; give oxygen, aspirin if an MI is suspected, and call EMS.
• Q: An endodontic file slips and the patient coughs violently. What next? A: Encourage coughing if the cough is effective; if not, five back blows and five abdominal thrusts; then chest and abdominal radiographs and urgent referral, as an aspirated file usually lodges in the right main bronchus — and prevent it with a rubber dam and floss ligature.
• Q: Why is the pregnant patient in the third trimester not kept supine? A: The gravid uterus compresses the inferior vena cava, reducing venous return and causing supine hypotensive syndrome; the left lateral position relieves it.
• Q: What are the early signs of local anaesthetic toxicity? A: Circumoral numbness, metallic taste, tinnitus, light-headedness, talkativeness and muscle twitching, progressing to seizures and then respiratory and cardiac depression.
• Q: How much steroid cover does a patient on long-term prednisolone need for an extraction? A: Most minor dental procedures under good local anaesthesia need no extra steroid, but for major surgical stress or signs of adrenal insufficiency give hydrocortisone 100–200 mg and liaise with the physician; protocols vary, so follow the treating physician's advice.
• Q: Which regulator governs dental practice in India today? A: The National Dental Commission, constituted under the National Dental Commission Act, 2023, which replaced the Dentists Act, 1948 and the Dental Council of India.

Common mistakes

• Quoting the adrenaline concentration wrongly — writing 1:1000 as 1 mg/mL is correct, but confusing it with 1:100,000 (0.01 mg/mL) gives a hundred-fold dosing error in the answer.
• Giving oxygen in hyperventilation, or sitting a syncopal patient upright — both make the condition worse.
• Calculating the local anaesthetic limit from the drug alone and ignoring the vasoconstrictor ceiling, which is usually the binding limit in a cardiac patient.
• Forcing a spoon, gauze or finger between the teeth during a seizure, or restraining the limbs — causes fractured teeth, aspiration and injury.
• Starting CPR on the raised, cushioned dental chair instead of flattening it or moving the patient to the floor, so compression depth is lost in chair flex.
• Giving an antihistamine or hydrocortisone first in anaphylaxis — they are adjuncts; delay in adrenaline is the usual cause of death.
• Using a child's dose as a fraction "by age" instead of calculating mg/kg, and forgetting that a single cartridge can approach the limit in a small child.
• Treating ASA IV patients electively in the clinic, or not recording vitals and drug times — indefensible in a consumer-forum or NDC inquiry.

Related topics

Local anaesthesia in dentistry · Oral and maxillofacial surgery: extractions and minor oral surgery · Management of the medically compromised dental patient · Pharmacology of emergency drugs · Conscious sedation and general anaesthesia in dentistry · Infection control and biomedical waste management