NBDE Part II cheat sheet

Working length typically ends 0.5–1.0 mm short of the radiographic apex; electronic apex locators locate the apical constriction accurately in roughly 80–95% of canals.

Sodium hypochlorite (0.5–5.25%) dissolves organic tissue and is antimicrobial; 17% EDTA chelates and removes the smear layer; NaOCl must not contact chlorhexidine because a precipitate forms.

Chlorhexidine 2% binds to dentin and provides substantivity, but it cannot dissolve tissue and is not virucidal.

Apical enlargement is complete when the canal is instrumented at least three file sizes larger than the first file that binds at working length.

Crown-down preparation removes coronal interferences first, improving irrigant penetration and reducing extrusion of debris and bacteria.

Reversible pulpitis: sharp pain provoked by cold that resolves quickly. Irreversible pulpitis: spontaneous or lingering pain. Necrotic pulp: no response to cold or electric pulp testing.

A sodium hypochlorite accident causes immediate severe pain, swelling, and possible paresthesia; manage with copious saline irrigation, analgesia, and observation.

Hedstrom files cut on the pull stroke, K-files cut on rotation, and rotary nickel-titanium instruments are superelastic and require torque control to prevent separation.

Amalgam requires a 90-degree cavosurface margin with no bevel and depends on mechanical retention; it is contraindicated for esthetic areas and true mercury allergy.

For total-etch bonding, etch enamel with 37% phosphoric acid for 15–30 seconds and dentin for 10–15 seconds; enamel bond strengths exceed dentin bond strengths.

Polymerization shrinkage creates C-factor stress at bonded walls; place increments no thicker than about 2 mm and consider a flowable intermediate layer.

Glass ionomer bonds chemically through polyacrylic acid, releases fluoride, and is indicated for class V lesions, pediatric restorations, and high caries risk patients.

The critical pH for enamel demineralization is about 5.5, while dentin demineralizes at a higher pH of roughly 6.0–6.5.

Calcium hydroxide is used as a liner in deep preparations close to the pulp; resin-modified glass ionomer serves as a base under restorative material.

Bonding generations: fourth = three-step etch-and-rinse, fifth = two-step etch-and-rinse, sixth = self-etch, seventh = universal adhesive.

Cast gold requires a beveled enamel margin with 1–1.5 mm occlusal clearance; ceramic requires 1.5–2 mm clearance and a shoulder or heavy chamfer.

A 2% lidocaine cartridge with 1:100,000 epinephrine contains 36 mg lidocaine and 0.018 mg epinephrine in 1.8 mL.

Maximum lidocaine dose is 7 mg/kg (about 500 mg) with epinephrine; articaine is 7 mg/kg; prilocaine is 8 mg/kg and can cause methemoglobinemia.

Inferior alveolar nerve block targets the lingula with the needle 6–10 mm above the mandibular occlusal plane, depositing about 1.5 mL.

Bupivacaine 0.5% with 1:200,000 epinephrine provides the longest soft tissue anesthesia, lasting up to 8–12 hours.

Syncope is the most common medical emergency in dental practice; manage by placing the patient supine with legs elevated.

Alveolar osteitis (dry socket) appears 3–5 days after extraction with severe pain and an empty socket; treat with irrigation and a medicated dressing rather than routine antibiotics.

AHA infective endocarditis prophylaxis is 2 g amoxicillin 30–60 minutes preoperatively; alternatives include cephalexin, azithromycin, or doxycycline.

Third molars are described by Winter's angulation (mesioangular, distoangular, vertical, horizontal) and by Pell–Gregory depth and ramus relationship.

Ludwig's angina is bilateral cellulitis of the submandibular, sublingual, and submental spaces; management is airway protection, IV antibiotics, and surgical drainage.

Primary teeth erupt from about 6 months to 2.5 years; the first permanent molar erupts at about 6 years, and the mixed dentition spans roughly 6–12 years.

Leeway space is about 1.7 mm per side in the mandible and 0.9 mm per side in the maxilla, totaling approximately 3.4 mm and 1.5 mm.

Tanaka–Johnston analysis adds half the sum of the four mandibular incisor widths to 10.5 mm for the mandible or 11.0 mm for the maxilla to predict canine and premolar width.

Common cephalometric norms are SNA 82 degrees, SNB 80 degrees, and ANB 2 degrees.

Angle Class II division 1 shows increased overjet with proclined maxillary incisors; division 2 shows deep bite with retroclined central incisors.

A first dental visit is recommended by age 1 or within 6 months of the first tooth; high-risk children receive fluoride varnish every 3–6 months.

A band and loop maintains space for a single lost primary molar; a Nance appliance or transpalatal arch maintains maxillary arch space.

Stainless steel crowns are indicated for multisurface caries in primary molars; pulpotomy agents include formocresol, ferric sulfate, and MTA.

Probing depths of 1–3 mm are healthy; attachment loss, not pocket depth alone, defines periodontitis.

The 2018 classification uses stages I–IV for severity and complexity and grades A–C for progression rate; grade C includes rapid progression and molar–incisor patterns.

Horizontal bone loss is more common, whereas vertical (angular) defects are amenable to regenerative procedures.

Furcation involvement classes I–IV describe horizontal and vertical components; class III is through-and-through.

Necrotizing ulcerative gingivitis is a fusospirochetal infection with punched-out papillae, pseudomembrane, bleeding, and halitosis; treat with debridement and metronidazole.

Localized aggressive periodontitis (grade C) is associated with Aggregatibacter actinomycetemcomitans and neutrophil dysfunction.

Subantimicrobial-dose doxycycline (20 mg twice daily) inhibits matrix metalloproteinases without producing an antibacterial effect.

Major risk factors include smoking, poorly controlled diabetes, plaque, and genetics; scaling and root planing is the initial nonsurgical therapy.

Adequate keratinized tissue is traditionally at least 2 mm of keratinized gingiva with at least 1 mm attached.

Kennedy classes I–IV follow Applegate's rules: the most posterior edentulous area determines the class, and a third molar is not counted unless it will be replaced.

A mandibular lingual bar needs at least 8 mm of floor-of-mouth depth, 4 mm height, 2 mm thickness, and sits about 3 mm below the gingival margins.

Complete denture success depends on retention, stability, and support, with balanced occlusion in centric and eccentric positions and 2–4 mm of freeway space.

For a post and core, leave 4–5 mm of apical gutta-percha and create a 1.5–2 mm ferrule of sound dentin.

Margin design: chamfer for metal-ceramic, shoulder for all-ceramic, and knife-edge only for full metal crowns.

Removable partial denture rests seat on prepared rest seats and direct occlusal forces along the long axis of abutment teeth.

Occlusal vertical dimension is verified using freeway space and facial esthetics; excessive loss of vertical dimension increases interocclusal distance.

Implant planning avoids placement within 5 mm of the mental foramen and maintains at least 2 mm from adjacent roots; primary stability enables osseointegration.

SLOB rule: when the tube head shifts, an object moving in the same direction is lingual, and one moving opposite is buccal.

In panoramic radiography the focal trough is a curved zone of sharpness; objects outside it are distorted, and ghost images appear on the opposite side and higher.

Bitewing contacts overlap when horizontal angulation is incorrect; a typical vertical angulation is about +10 degrees.

F-speed film is the fastest intraoral film, and digital sensors reduce dose further; ALARA governs all exposures.

A periapical radiolucency with loss of the lamina dura suggests apical periodontitis; widening of the periodontal ligament may be an early sign.

ASA classification: I healthy, II mild systemic disease, III severe disease not incapacitating, IV incapacitating and life-threatening disease.

Incisional biopsy is used for suspected malignancy or large lesions; excisional biopsy for small benign lesions; cytology for fluids and surface smears.

Cone-beam computed tomography provides three-dimensional imaging at a fraction of medical CT dose for impacted teeth, canal anatomy, and implant planning.

Amoxicillin 500 mg every 8 hours is first-line for odontogenic infection; penicillin-allergic patients may receive clindamycin, azithromycin, or cephalexin.

NSAIDs inhibit cyclooxygenase; aspirin is irreversible and affects platelets for 7–10 days, while ibuprofen is reversible and short acting.

Epinephrine in local anesthetics interacts with nonselective beta-blockers to cause hypertensive crisis and with tricyclic antidepressants to potentiate pressor effects.

Naloxone reverses opioid-induced respiratory depression; flumazenil reverses benzodiazepine sedation.

Warfarin therapy is monitored by INR; most dental procedures are safe below INR 3.5, and erythromycin or metronidazole increase bleeding risk.

MRONJ risk rises with intravenous bisphosphonates and antiangiogenic agents; elective surgery is avoided when possible and drug holidays are decided by the oncologist.

Metronidazole with alcohol produces a disulfiram-like reaction, so alcohol is avoided during therapy and for 3 days afterward.

Clark's rule calculates pediatric dose as (weight in pounds divided by 150) multiplied by the adult dose.

Squamous cell carcinoma is the most common oral malignancy; tobacco and alcohol are the major risk factors, and erythroplakia carries the highest malignant transformation rate.

The radicular cyst is the most common odontogenic cyst; a dentigerous cyst surrounds the crown of an impacted tooth; odontogenic keratocysts have high recurrence rates.

Ameloblastoma produces a soap-bubble radiolucency in the posterior mandible and requires resection with margins because of local aggressiveness.

Odontoma is the most common odontogenic tumor and is a hamartoma; the compound type contains toothlike structures, the complex type is disorganized.

Gorlin syndrome features multiple odontogenic keratocysts, bifid ribs, basal cell carcinomas, palmar pits, and a calcified falx cerebri.

Oral lichen planus presents with bilateral Wickham striae and may erode; erosive lesions require biopsy to exclude dysplasia.

A mucocele results from minor salivary gland duct retention, while a ranula is a large mucocele in the floor of the mouth.

Recurrent intraoral herpes appears on keratinized mucosa such as the hard palate after a prodrome of tingling or burning.

Candidiasis may be pseudomembranous, erythematous, or hyperplastic; topical nystatin or systemic fluconazole is used.

Tell–show–do, positive reinforcement, distraction, and voice control are first-line behavior guidance techniques for children.

The Frankl scale rates behavior: 1 definitely negative, 2 negative, 3 positive, 4 definitely positive.

Informed consent requires capacity, disclosure, comprehension, and voluntariness; minors need guardian consent except emancipated minors.

HIPAA protects identifiable health information; disclosure requires authorization except for treatment, payment, operations, and legally mandated reporting.

Core ethical principles are autonomy, beneficence, nonmaleficence, justice, and veracity.

Suspected child abuse or neglect must be reported to designated authorities even though confidentiality ordinarily applies.

Dental anxiety is managed by recognition and assessment, with behavioral methods or adjuncts such as nitrous oxide–oxygen or benzodiazepines.

The standard of care is what a reasonably prudent practitioner would do under similar circumstances.

DMFT and dmft indices count decayed, missing, and filled teeth; DMFS and dmfs count surfaces.

Community water fluoridation is optimal at 0.7 mg/L and reduces caries experience by roughly 25% in a population.

Dental fluorosis is graded with Dean's index; risk rises when water fluoride exceeds optimal levels, with climate affecting intake.

Prevalence is the proportion with disease at a given time; incidence is the number of new cases over a period.

Sensitivity equals true positives divided by true positives plus false negatives; specificity equals true negatives divided by true negatives plus false positives.

The Community Periodontal Index uses a special probe and scores 0–4 for bleeding, calculus, and probing depth.

Cohort studies measure incidence and relative risk, case-control studies yield odds ratios, and cross-sectional studies measure prevalence.

National oral health objectives are set through Healthy People, and school-based sealant programs target high-risk communities.