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Aluminum chloride is the most commonly used mummifying agent in gingival retraction cords because it effectively causes hemosasis and mild astringency without significant tissue irritation. It works by precipitating proteins, leading to gentle hemostasis and shrinkage of the gingival tissues, which facilitates clear impressions. Compared to other agents like ferric sulfate, aluminum chloride is less acidic and causes minimal post-operative tissue inflammation, making it safer for delicate gingival tissues during dental procedures. Its compatibility with impression materials also enhances clinical outcomes.

Reference: Principles and Practice of Operative Dentistry, Satheesh Kumar, 4th Edition.
The main objective of root canal therapy is to eliminate infection from the pulp tissue inside the tooth and to preserve the natural tooth structure. This procedure involves removing infected or necrotic pulp, cleaning and disinfecting the root canal system, and then filling it to prevent reinfection. By doing so, root canal therapy prevents the need for tooth extraction, maintains the tooth’s function, and supports surrounding oral structures. This approach is essential for saving the tooth and avoiding complications such as abscess formation or systemic infection.

Reference: Principles and Practice of Endodontics, Mahmoud Torabinejad, 5th Edition.
Lidocaine is the preferred local anesthetic for pregnant women because it has a well-established safety profile and is classified as FDA pregnancy category B. It has minimal placental transfer and low fetal toxicity, making it safer for both mother and fetus during surgical procedures. Additionally, lidocaine provides effective anesthesia with a rapid onset and intermediate duration, which is suitable for most obstetric and minor surgical interventions. Other local anesthetics like bupivacaine carry higher risks of cardiotoxicity and fetal complications. Therefore, lidocaine is the anesthetic of choice due to its proven maternal and fetal safety.

Reference: Miller's Anesthesia, Miller RD, 9th Edition.
Lorazepam is considered the safest sedative in patients with hepatic impairment because it undergoes conjugation via glucuronidation, an extrahepatic metabolic pathway largely independent of liver function. Unlike diazepam, midazolam, and chlordiazepoxide, which require oxidative metabolism by the liver’s cytochrome P450 system, lorazepam’s metabolism is less affected by hepatic dysfunction, resulting in more predictable pharmacokinetics and reduced risk of accumulation and toxicity. This makes lorazepam ideal for sedation in patients with compromised liver function.

Reference: Goodman & Gilman’s The Pharmacological Basis of Therapeutics, Brunton et al., 13th Edition.
When metronidazole is taken with alcohol, it can cause a disulfiram-like reaction, characterized by flushing, nausea, vomiting, headache, and tachycardia. This happens because metronidazole inhibits the enzyme aldehyde dehydrogenase, leading to the accumulation of acetaldehyde, a toxic metabolite of alcohol. The buildup of acetaldehyde triggers these unpleasant symptoms, similar to those experienced with disulfiram, a drug used to deter alcohol consumption. This reaction is important to recognize and avoid by advising patients to abstain from alcohol during and for at least 48 hours after metronidazole therapy.

Reference: Katzung BG, Basic and Clinical Pharmacology, 15th Edition.
The WHO Model List of Essential Medicines is revised every 2 years to ensure it reflects the latest evidence on the safety, efficacy, and cost-effectiveness of medicines. This frequency allows for timely updates in response to emerging health challenges, new therapeutic options, and changes in disease patterns worldwide. Regular revisions help guide healthcare systems in selecting the most appropriate and essential medicines to meet the priority health needs of their populations. Thus, a biennial update balances the need for current guidance with practical review cycles.

Reference: WHO Model List of Essential Medicines, World Health Organization, Latest Edition.
The correct answer is Naloxone.

- Opioid overdose can lead to respiratory depression, which is a dangerously reduced breathing rate and can be life-threatening.
- This happens because opioids bind to mu-opioid receptors in the central nervous system, suppressing the brain's drive to breathe.

- Naloxone is an opioid antagonist, meaning it competitively binds to opioid receptors without activating them.
- By doing so, naloxone reverses the effects of opioids, particularly respiratory depression.
- It is administered emergently in cases of suspected opioid overdose to restore normal breathing.

Other options are not appropriate for opioid overdose:
- Flumazenil (Option 1) is used to reverse benzodiazepine overdose, not opioid overdose.
- Atropine (Option 3) is an anticholinergic agent used for bradycardia and some poisoning but does not reverse opioid respiratory depression.
- Diazepam (Option 4) is a benzodiazepine and would potentially worsen respiratory depression if opioids are involved.

In summary, naloxone is the first-line treatment for opioid-induced respiratory depression due to its ability to rapidly displace opioids from central receptors, restoring respiratory drive.

Reference: Goodman & Gilman's: The Pharmacological Basis of Therapeutics, 13th Edition, Chapter 19, Opioid Analgesics and Antagonists
The correct answer is Tetracycline.

- Tetracycline antibiotics are well-known for their ability to cause permanent tooth staining when administered to pediatric patients, especially those younger than 8 years old.
- This occurs because tetracycline binds to calcium ions in developing teeth and bones, leading to a characteristic yellow, brown, or gray discoloration of the teeth.
- This staining is often intrinsic and irreversible, affecting both deciduous and permanent teeth.

Additionally, tetracycline may interfere with normal bone growth in children, further limiting its use in the pediatric population. For these reasons, clinicians typically avoid prescribing tetracycline to children and pregnant women.

In contrast, other antibiotics listed such as chloramphenicol, ampicillin, and erythromycin do not cause permanent tooth discoloration and are generally considered safer options for use in pediatric infections.

Key points:
- Tetracycline binds to calcium in developing teeth and bones.
- Causes permanent intrinsic tooth discoloration (yellow-brown-gray staining).
- Not recommended in children under 8 years and in pregnant women.
- Other antibiotics listed do not induce tooth staining.

Reference: Harrison's Principles of Internal Medicine, 20th Edition, Volume 2, Infectious Diseases Chapter, p. 1250
The medication most commonly associated with the development of oral candidiasis is inhaled corticosteroids.

- Oral candidiasis, also known as oral thrush, is a fungal infection caused by the overgrowth of Candida species, particularly Candida albicans, in the oral mucosa.
- The use of certain medications can predispose to this condition by disrupting the normal flora or local immunity.

- Inhaled corticosteroids are widely used in the management of asthma and chronic obstructive pulmonary disease (COPD). These drugs deposit corticosteroid particles in the oropharynx, leading to localized immunosuppression. This local suppression of immune defenses enables Candida to proliferate, resulting in oral candidiasis. The risk is increased if patients do not rinse their mouth after inhaler use.

- Systemic antibiotics can also predispose to candidiasis by disrupting normal bacterial flora, but they are more commonly associated with candidiasis in other sites such as the gastrointestinal tract or vaginal mucosa rather than primarily in the oral cavity.

- Oral beta-blockers and topical nonsteroidal anti-inflammatory drugs (NSAIDs) do not have a well-established association with the development of oral candidiasis.

In summary, inhaled corticosteroids are the most common medication class linked to the development of oral candidiasis due to localized immunosuppression in the oral mucosa.

Reference: Harrison's Principles of Internal Medicine, 20th Edition, Volume 2, Chapter 330: Fungal infections

ফ্রিতে ২ লাখ প্রশ্নের টপিক, সাব-টপিক ভিত্তিক ও ১০০০+ জব শুলুশন্স বিস্তারিতে ব্যাখ্যাসহ পড়তে ও আপনার পড়ার ট্র্যাকিং রাখতে সাইটে লগইন করুন।

লগইন করুন
The group of antihypertensive medications commonly associated with the development of oral lichenoid lesions is Beta-blockers.

- Oral lichenoid lesions (OLLs) are mucosal reactions that resemble oral lichen planus clinically and histologically but are often triggered by certain medications or contact allergens.
- Among antihypertensive drugs, beta-blockers have been frequently reported to induce oral lichenoid reactions.
- These lesions typically present as white, reticular, or erosive patches on the oral mucosa and can cause discomfort or burning sensations.
- The pathogenesis involves a delayed-type hypersensitivity reaction to the drug or its metabolites, resulting in an immune-mediated mucosal injury.
- While other antihypertensive classes such as calcium channel blockers and ACE inhibitors have also been associated with lichenoid lesions, the strongest and most consistent evidence links beta-blockers to this adverse effect.
- Recognizing this association is critical because discontinuing or substituting the offending drug can lead to resolution of the lesions.

In summary:
- Beta-blockers are the most commonly implicated antihypertensive drugs in oral lichenoid lesions.
- These lesions mimic oral lichen planus but are drug-induced.
- Management includes identification and withdrawal of the causative medication.

Reference: Oral Medicine and Pathology, 3rd Edition, Volume 2, Chapter 15, Pages 250-255
When managing pain in patients with compromised renal function, selecting an opioid analgesic with a safer metabolic profile is crucial to avoid accumulation of active metabolites that can cause toxicity.

- Morphine and codeine are primarily metabolized in the liver to active metabolites that are excreted renally.
- In patients with impaired renal function, these metabolites can accumulate, leading to increased risk of respiratory depression, sedation, and neurotoxicity.

- Hydromorphone also has active metabolites that are renally excreted and may accumulate in renal impairment, although to a lesser extent than morphine.

In contrast, fentanyl is metabolized mainly by the liver through CYP3A4 to inactive metabolites and has minimal renal excretion. Due to this pharmacokinetic profile, fentanyl does not accumulate in patients with renal dysfunction, making it the preferred opioid for pain management in this population.

Key points:
- Morphine and codeine: Active metabolites accumulate in renal impairment → increased toxicity risk
- Hydromorphone: Active metabolites present, cautious use required
- Fentanyl: Metabolized to inactive metabolites, minimal renal excretion → safer in renal failure

Therefore, fentanyl is preferred for pain management in patients with compromised renal function due to its safer metabolic and excretion profile.

Reference: Goodman & Gilman's The Pharmacological Basis of Therapeutics, 13th Edition, Volume 1, Chapter 25 (Opioid Analgesics)
The most commonly recommended antihistamine as premedication for patients with a history of allergies prior to dental procedures is Diphenhydramine.

- Diphenhydramine is a first-generation antihistamine known for its strong H1 receptor antagonism and effective prevention of allergic reactions.
- It has sedative properties, which can be beneficial in reducing anxiety during dental procedures.
- Due to its rapid onset of action and ability to be administered orally or intramuscularly, it is preferred for immediate premedication.
- Unlike second-generation antihistamines such as Cetirizine, Loratadine, and Fexofenadine, diphenhydramine can cross the blood-brain barrier, leading to sedation, which is useful in procedural settings.
- Second-generation antihistamines are typically less sedating and have a slower onset, making them less effective for acute premedication use.

Thus, Diphenhydramine is preferred for its quick onset, sedative effect, and strong antihistamine action, ensuring better protection against allergic reactions during dental interventions.

Reference: Gray’s Anatomy of the Human Body, Volume 1, Chapter 15 – Allergic Reactions and Antihistamines, p. 245-247
The specific antidote for benzodiazepine toxicity is Flumazenil. Benzodiazepines exert their effects by enhancing the activity of the neurotransmitter gamma-aminobutyric acid (GABA) at the GABA-A receptor. In cases of overdose or toxicity, this results in CNS depression, sedation, respiratory depression, and potentially coma.

- Flumazenil is a benzodiazepine receptor antagonist that competitively inhibits the binding of benzodiazepines at the GABA-A receptor.
- By doing so, it reverses the sedative and hypnotic effects of benzodiazepines rapidly and effectively.
- It is important to use flumazenil cautiously, as it can precipitate withdrawal seizures in patients with chronic benzodiazepine use or dependence.

The other options provided are antidotes for different toxicities:
- Naloxone is an opioid antagonist used for opioid overdose.
- Atropine is an anticholinergic agent used primarily for organophosphate poisoning or bradycardia.
- Physostigmine is a cholinesterase inhibitor used as an antidote in anticholinergic toxicity.

Therefore, for suspected benzodiazepine overdose, Flumazenil remains the specific and targeted antidote.

Reference: Goldfrank's Toxicologic Emergencies, 12th Edition, Chapter on Sedative-Hypnotic Agents, Page 541
The antibiotic most commonly associated with causing a metallic taste sensation in the oral cavity is Metronidazole.

- Metronidazole is known to cause several distinctive side effects, one of which is a metallic or bitter taste that patients often report during the course of treatment.
- This adverse effect occurs because Metronidazole interacts with the taste receptors or alters the normal flora in the oral cavity, leading to changes in taste perception.

- In contrast, other antibiotics such as Clindamycin, Amoxicillin, and Erythromycin are less frequently associated with taste disturbances.
- While these antibiotics can cause other side effects like gastrointestinal upset or allergic reactions, a metallic taste is not a common complaint.

Key Points:
- Metronidazole is the antibiotic most frequently linked to a metallic taste sensation.
- The metallic taste is a known and documented side effect during its use.
- Other antibiotics in the list do not typically cause this taste disturbance.

Understanding the side effect profile of antibiotics is essential for patient counseling and managing expectations during treatment.

Reference: Goodman & Gilman's The Pharmacological Basis of Therapeutics, 13th Edition, Volume 2, Chapter 43, Page 1122
The correct answer is Warfarin.

- Warfarin is a vitamin K antagonist that has been used for decades as an oral anticoagulant.
- One of the critical aspects of warfarin therapy is the need for routine monitoring of the International Normalized Ratio (INR) to ensure the drug remains within the therapeutic range.
- This is essential because warfarin’s anticoagulant effect can be influenced by various factors, including dietary vitamin K intake, drug interactions, and individual metabolism variability.
- Maintaining the INR within the target range helps balance the risk of thrombosis versus bleeding complications.

- In contrast, the newer direct oral anticoagulants (DOACs), such as Dabigatran, Rivaroxaban, and Apixaban, have predictable pharmacokinetics and pharmacodynamics and do not require routine INR monitoring.
- These agents are generally preferred for their fixed dosing and fewer dietary restrictions but may need dose adjustment in certain clinical situations such as renal impairment.

Key points:
- Warfarin requires regular INR monitoring to guide dosing.
- INR monitoring prevents complications related to under- or over-anticoagulation.
- DOACs (Dabigatran, Rivaroxaban, Apixaban) do not require routine INR monitoring.

Reference: Harrison's Principles of Internal Medicine, 20th Edition, Volume 2, Chapter 198: Anticoagulant Therapy, Page 1656-1658.
The correct answer is Aspirin.

- Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) can precipitate bronchospasm in patients with asthma, especially those with the condition known as Aspirin-Exacerbated Respiratory Disease (AERD).
- This occurs because aspirin inhibits the cyclooxygenase (COX) enzyme, leading to a shunting of arachidonic acid metabolism towards the production of leukotrienes, which are potent bronchoconstrictors.
- This leukotriene-mediated pathway can cause acute bronchospasm and worsening of asthma symptoms.

In contrast:

- Paracetamol (acetaminophen) is generally considered safe for asthmatic patients, although rare hypersensitivity reactions can occur.

- Diclofenac, like aspirin, is an NSAID and may potentially cause bronchospasm, but it is less commonly implicated compared to aspirin.

- Tramadol is an opioid analgesic with minimal effect on bronchospasm and is not contraindicated in asthma.

Therefore, aspirin should be avoided in asthmatic patients due to the risk of exacerbating bronchospasm.

Reference: Harrison's Principles of Internal Medicine, 20th Edition, Chapter 323: Asthma, Page 2100
In managing acute anaphylactic reactions during dental procedures, the first-line treatment is epinephrine.

- Epinephrine acts rapidly to counteract the life-threatening symptoms of anaphylaxis by vasoconstriction, bronchodilation, and increasing cardiac output.
- It reverses airway obstruction, hypotension, and reduces edema, making it essential for immediate administration at the onset of anaphylaxis.

- While medications such as diphenhydramine, hydrocortisone, and albuterol can be helpful as adjunctive therapies, they do not address the primary pathophysiology of anaphylaxis as quickly or effectively as epinephrine.
- Diphenhydramine, an antihistamine, can alleviate hives and itching but has no role in managing airway compromise or shock.
- Hydrocortisone is useful for preventing biphasic or prolonged reactions but has a delayed onset of action.
- Albuterol can help treat bronchospasm but is secondary to the systemic effects needed in anaphylaxis.

Key Points:
- Epinephrine is the immediate and primary intervention in acute anaphylaxis.
- It acts by rapid vasoconstriction and bronchodilation.
- Adjunctive therapies such as antihistamines, corticosteroids, and bronchodilators are supportive but not first-line.
- Delay in epinephrine administration can result in progression to severe or fatal anaphylaxis.

Reference: Dental Management of the Medically Compromised Patient, 9th Edition, Chapter 12: Allergic and Anaphylactic Reactions, Page 345-350
The safest local anesthetic for use during pregnancy is Lidocaine.

- During pregnancy, the choice of local anesthetic must consider both maternal and fetal safety.
- Lidocaine is classified as a Category B drug by the FDA, meaning that animal studies have not demonstrated a risk to the fetus, and there are no adequate and well-controlled studies in pregnant women but it is widely regarded as safe when used appropriately.

- Bupivacaine has a longer duration and higher potential for cardiotoxicity, making it less desirable during pregnancy. It is usually reserved for procedures where prolonged anesthesia is required, but caution is advised.
- Mepivacaine is category C and has less data regarding safety in pregnancy, so it is generally avoided.
- Prilocaine contains methemoglobin-forming potential, which can pose an additional risk especially to the fetus and neonate.

Therefore, because of its established safety profile, Lidocaine is considered the safest and most commonly used local anesthetic during pregnancy.

Reference: Chestnut's Obstetric Anesthesia: Principles and Practice, 6th Edition, Volume 1, Chapter 15, Page 234
Dry mouth, also known as xerostomia, is a common side effect of many medications. The category of medications most frequently associated with causing drug-induced dry mouth is anticholinergics.

Anticholinergic drugs work by blocking the action of acetylcholine on muscarinic receptors in the parasympathetic nervous system. Since acetylcholine is crucial for stimulating salivary gland secretion, this blockade leads to reduced saliva production and thus, dry mouth. This effect is more pronounced with medications that have strong anticholinergic properties.

While antihistamines and diuretics can also contribute to dry mouth, their mechanisms differ and are usually less significant compared to anticholinergics. Beta blockers are not commonly linked to dry mouth and are less likely to cause this side effect.

Understanding the role of anticholinergic activity is important for clinicians when prescribing medications, especially in populations vulnerable to xerostomia, such as the elderly, to help mitigate complications like dental caries, oral infections, and difficulty swallowing.

Reference: Goodman & Gilman’s The Pharmacological Basis of Therapeutics, 13th Edition, Chapter 10 / Page 256

ফ্রিতে ২ লাখ প্রশ্নের টপিক, সাব-টপিক ভিত্তিক ও ১০০০+ জব শুলুশন্স বিস্তারিতে ব্যাখ্যাসহ পড়তে ও আপনার পড়ার ট্র্যাকিং রাখতে সাইটে লগইন করুন।

লগইন করুন
The drug of choice for treating oral candidiasis in patients with compromised immune systems is Fluconazole. This is because Fluconazole is a systemic antifungal agent that provides effective and reliable oral bioavailability, allowing it to reach therapeutic concentrations in saliva and mucosal tissues.

Key points to consider:

- Fluconazole is a triazole antifungal that inhibits fungal cytochrome P450 enzyme 14α-demethylase, impairing ergosterol synthesis, which is essential for fungal cell membrane integrity.
- It has a broad spectrum of action against Candida species, including Candida albicans, the most common cause of oral candidiasis.
- Fluconazole is well tolerated and has a favorable safety profile with minimal side effects.
- It has the advantage of systemic administration, making it more effective than topical agents in immunocompromised patients where mucosal penetration and eradication are critical.
- Nystatin, although effective against oral candidiasis, is a topical agent which is less ideal for immunocompromised patients due to limited tissue penetration.
- Itraconazole and Voriconazole are other systemic azoles but are generally reserved for more resistant or invasive fungal infections and have a less favorable side effect profile or drug interaction potential for routine oral candidiasis treatment.

Therefore, Fluconazole remains the first-line therapy for oral candidiasis, especially in immunocompromised hosts such as HIV/AIDS patients, transplant recipients, or cancer patients undergoing chemotherapy.

Reference: Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases, 9th Edition, Volume 2, Chapter 233/ Page 1947
The antibiotic most commonly linked to the development of pseudomembranous colitis caused by Clostridioides difficile is Clindamycin.

Pseudomembranous colitis is an inflammation of the colon associated with overgrowth of Clostridioides difficile, a gram-positive, spore-forming anaerobic bacterium. This condition typically arises after disruption of the normal colonic flora, which allows C. difficile to proliferate and produce toxins that damage the colonic mucosa.

Certain antibiotics, especially those with broad-spectrum activity, are more likely to disturb the gut microbiota and predispose patients to C. difficile infection (CDI). Among the antibiotics listed:

- Clindamycin is historically the most notorious for causing CDI because it has a strong impact on anaerobic bacteria in the gut, which normally suppress C. difficile growth.

- Ampicillin can also cause some disruption but is less commonly implicated.

- Ciprofloxacin and other fluoroquinolones have been associated with outbreaks of hypervirulent C. difficile strains but are generally less strongly linked compared to clindamycin in classic teaching.

- Azithromycin, a macrolide, has a lower risk for CDI.

Key points:
- Clindamycin significantly disrupts normal gut flora, increasing susceptibility to CDI.
- Broad-spectrum antibiotics that affect anaerobic bacteria contribute the most to pseudomembranous colitis.
- The overgrowth of C. difficile leads to toxin-mediated colonic mucosal injury and pseudomembrane formation.

Reference: Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases, 9th Edition, Volume 2, Chapter 147 - Clostridioides difficile Infection
The antihypertensive medication most commonly associated with the development of gingival overgrowth is Amlodipine.

Gingival overgrowth, also known as gingival hyperplasia, is a well-documented adverse effect linked primarily to certain classes of drugs, including calcium channel blockers (CCBs), anticonvulsants, and immunosuppressants. Among calcium channel blockers, Amlodipine and Nifedipine are frequently implicated.

- Amlodipine is a dihydropyridine calcium channel blocker commonly used to manage hypertension and angina.
- It can induce fibroblast proliferation and increase extracellular matrix production in gingival tissues leading to the characteristic overgrowth.
- The onset of gingival overgrowth due to Amlodipine typically occurs within 1–3 months of drug initiation, although this can vary based on individual patient factors such as oral hygiene and genetic predisposition.
- Lisinopril (an ACE inhibitor), Hydrochlorothiazide (a thiazide diuretic), and Metoprolol (a beta-blocker) are not commonly associated with gingival overgrowth.

Key Points:
- Amlodipine is a calcium channel blocker that commonly causes gingival overgrowth.
- Gingival overgrowth is due to fibroblast stimulation and excess collagen deposition.
- Good oral hygiene and drug substitution can mitigate this side effect.
- Lisinopril, Hydrochlorothiazide, and Metoprolol are not typically linked to gingival hyperplasia.

References:
- Harrison's Principles of Internal Medicine, 20th Edition, Volume 2, Chapter on Pharmacology, Page 1294
- Robbins Basic Pathology, 10th Edition, Chapter 11: Disorders of the Immune System, Page 390
The main role of sodium hypochlorite (NaOCl) irrigation during root canal therapy is to dissolve organic tissue remnants and disinfect the root canal system.

- Sodium hypochlorite is widely used as an irrigant because of its powerful antimicrobial properties and its ability to break down necrotic tissue, biofilms, and organic debris within the complex anatomy of the root canal.
- This helps in reducing bacterial load and ensures a cleaner canal space, which is essential for successful root canal treatment.

To clarify the options given:
- Option 1 (Remove inorganic smear layer): Sodium hypochlorite is not effective in removing inorganic components of the smear layer. For this purpose, chelating agents like EDTA are used.
- Option 3 (Enhance adhesion of root canal sealers): This is not a primary function of sodium hypochlorite. Adhesion is more related to the properties of the sealer and surface treatment.
- Option 4 (Neutralize acidic byproducts): Sodium hypochlorite does not serve this function.

Therefore, the primary and most critical role of sodium hypochlorite irrigation is to dissolve organic tissue remnants and disinfect the root canal system.

Reference: Hargreaves KM, Cohen S. *Cohen’s Pathways of the Pulp*, 12th Edition, Volume 1, Chapter 8: Root Canal Irrigation and Disinfection / Page 280-290
The clinical diagnosis of pulpitis—whether reversible or irreversible—relies heavily on the patient’s symptoms and diagnostic tests. Among the options provided, prolonged spontaneous pain is the most reliable indicator of irreversible pulpitis.

- Sharp pain on biting often suggests cracked tooth syndrome or occlusal trauma rather than pulp inflammation per se. It is not specific for irreversible pulpitis.

- Prolonged spontaneous pain refers to pain that occurs without any stimulus and lingers for an extended period (minutes to hours). This symptom reflects inflammation extending beyond the threshold where the pulp can heal, indicating irreversible pulpitis.

- Sensitivity to cold that resolves quickly is typical of reversible pulpitis, where the pulp is inflamed but still capable of healing once the irritant is removed.

- Mild discomfort only on thermal stimulation also suggests reversible pulpitis or a healthy pulp with minor irritation, not irreversible damage.

Key takeaway:
- Irreversible pulpitis is characterized by spontaneous, lingering pain.
- The presence of prolonged spontaneous pain signals that the pulp’s inflammation is severe and cannot recover, necessitating endodontic treatment (root canal therapy).

Reference: Cohen’s Pathways of the Pulp, 12th Edition, Chapter 5: Pulpal and Periapical Diagnosis / Pages 127-130
- The primary purpose of determining the working length during root canal therapy is to ensure the complete debridement of pulp tissue, bacteria, and necrotic debris up to the apical constriction.
- The working length is the distance from a coronal reference point to the point where canal preparation and filling should terminate.

Precisely establishing this length is critical because:
- Effective cleaning and shaping of the root canal system depends on accurate canal length measurement.
- It helps prevent over-instrumentation beyond the apical foramen, which can cause periapical tissue damage or irritation.
- It avoids under-instrumentation, which may leave residual infected tissue and reduce the success of treatment.

Options such as protecting the coronal enamel or measuring dentin thickness for posts are unrelated to the working length. While accessory canals do exist, their identification is not the primary purpose of determining working length.

Accurate working length determination is typically achieved through radiographs or electronic apex locators, helping the clinician optimize the outcome of root canal therapy.

Reference: Grossman’s Endodontic Practice, 13th Edition, Chapter 7: Cleaning and Shaping of the Root Canal System, p. 195-198
The most critical radiograph for the accurate diagnosis and treatment planning of root canal therapy is the Periapical radiograph.

- A periapical radiograph provides a detailed image of the entire tooth structure, including the crown, root, and surrounding bone.

This type of radiograph is essential because it allows clinicians to:
- Visualize the root apex and the surrounding periapical tissues, which is crucial for detecting any periapical pathology such as abscesses or cysts.
- Assess the length, shape, and number of root canals, aiding in proper cleaning, shaping, and obturation during root canal therapy.
- Monitor post-treatment healing by comparing pre- and post-operative images.

In contrast, other radiographs serve different purposes:
- Panoramic radiographs provide a broad overview of the jaws but lack the detail necessary for root canal treatment planning.
- Occlusal radiographs are typically used for locating impacted teeth or assessing maxillary and mandibular bone but do not provide detailed root and periapical views.
- Bitewing radiographs are primarily used to detect interproximal caries and bone levels, not root canal anatomy.

Therefore, the periapical radiograph remains the gold standard for diagnosing and planning endodontic treatment.

Reference: Orstavik D., Pitt Ford T.R., Hargreaves K.M., "Problem Solving in Endodontics", 2nd Edition, Chapter 3: Radiographic Assessment, Pages 45-60.
The primary factor responsible for the failure of root canal treatment is incomplete cleaning and shaping of root canals.

- During root canal therapy, the main goal is to thoroughly remove all necrotic tissue, bacteria, and infected pulp remnants from the root canal system.
- Failure to adequately clean and shape the canals can leave behind infected tissue or microbial biofilms that continue to multiply, leading to persistent infection and inflammation.
- This residual infection is the most common cause of treatment failure and can result in periapical pathology or abscess formation.

- Although other factors such as incorrect rubber dam placement and use of inadequate obturation materials can influence the outcome, they usually contribute indirectly or are secondary in comparison.
- Post-restoration infection is also possible but generally occurs as a consequence of inadequate initial disinfection.
- Hence, the cornerstone of successful root canal therapy remains effective cleaning and shaping to ensure proper disinfection of the complex root canal anatomy.

Key points:
- Complete removal of infected pulp tissue is critical.
- Effective shaping facilitates irrigation and obturation.
- Residual bacteria lead to treatment failure.

Reference: Grossman’s Endodontic Practice, 13th Edition, Chapter 5, Page 220
The most frequently used primary obturating substance in root canal therapy is gutta-percha.

- During root canal treatment, the aim is to completely fill and seal the cleaned and shaped root canal system to prevent reinfection.
- Gutta-percha is widely preferred because of its biocompatibility, dimensional stability, and ease of manipulation.
- It can be compacted effectively within the canal to create a fluid-tight seal when used with an appropriate sealer.

- Other materials listed, such as Resilon, are alternatives but have not achieved the same level of consistent clinical success and long-term reliability as gutta-percha.
- Calcium hydroxide is generally used as an intracanal medicament, not as a permanent obturating material.
- Zinc oxide eugenol cements are often used as sealers rather than the core filling material.

Thus, gutta-percha remains the gold standard for root canal obturation due to its versatility and proven effectiveness in clinical endodontics.
The local anesthetic agent most frequently used in combination with vasoconstrictors such as epinephrine is Lidocaine.

- Lidocaine is a widely preferred local anesthetic due to its rapid onset of action, intermediate duration, and excellent safety profile.
- The addition of a vasoconstrictor like epinephrine prolongs the anesthetic effect by constricting blood vessels, which reduces systemic absorption of the anesthetic, minimizes bleeding in the surgical site, and decreases the potential for toxicity.

- While other local anesthetics such as bupivacaine, prilocaine, and mepivacaine can also be used with vasoconstrictors, Lidocaine's versatility and favorable characteristics make it the most commonly utilized agent in clinical practice.

Key points:
- Lidocaine has a rapid onset and moderate duration.
- Epinephrine acts as a vasoconstrictor to prolong anesthesia and decrease bleeding.
- Combination improves safety by reducing systemic absorption.
- Other agents are available but Lidocaine remains the standard first-line choice.

Reference: Basic and Clinical Pharmacology, 15th Edition, Chapter 28, Local Anesthetics, Page 340-345

ফ্রিতে ২ লাখ প্রশ্নের টপিক, সাব-টপিক ভিত্তিক ও ১০০০+ জব শুলুশন্স বিস্তারিতে ব্যাখ্যাসহ পড়তে ও আপনার পড়ার ট্র্যাকিং রাখতে সাইটে লগইন করুন।

লগইন করুন
The correct answer is Bupivacaine.

- Among the commonly used local anesthetics, bupivacaine is well-known for its higher risk of cardiotoxicity when inadvertently administered intravenously or absorbed in excessive amounts.
- This is primarily due to its high lipid solubility and strong binding affinity to cardiac sodium channels, which results in prolonged sodium channel blockade and impaired cardiac conduction and contractility.
- Clinically, this can manifest as ventricular arrhythmias, severe hypotension, and even cardiac arrest.

In contrast, other local anesthetics like lidocaine and mepivacaine have a comparatively safer cardiac profile. Lidocaine, although it has some cardiac effects, is often used as an antiarrhythmic agent and is less likely to cause severe cardiotoxicity at accidental intravenous doses. Mepivacaine and prilocaine also have lower cardiotoxicity risk relative to bupivacaine.

Key points:
- Bupivacaine has a high affinity for cardiac sodium channels, leading to more profound and prolonged sodium channel blockade.
- This causes severe cardiac arrhythmias and cardiotoxicity in the event of accidental intravascular injection.
- Lidocaine and other local anesthetics like mepivacaine and prilocaine have a comparatively lower risk of cardiotoxicity.
- Caution and proper aspiration before injection are essential to minimize intravascular administration risks with bupivacaine.

Reference: Harold Ellis, Clinical Anesthesia, Volume 1, Chapter 15 - Local Anesthetics and Their Systemic Toxicity, Page 265-270.
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