NHRA Dentist Exam cheat sheet

Recurrent aphthous stomatitis: minor (<10 mm, heals ≤14 days, no scar), major (>10 mm, 2-6 weeks, scars), herpetiform (1-3 mm clusters).

Oral lichen planus vs lichenoid reaction: bilateral buccal Wickham striae favor lichen planus; unilateral, adjacent to restoration, or drug-related favors lichenoid; lichen planus carries low malignant transformation risk (~1%).

Leukoplakia is a clinical diagnosis of exclusion (white patch not attributable to another cause); erythroplakia has higher dysplasia/malignancy risk than homogeneous leukoplakia.

Oral potentially malignant disorders warrant biopsy when: non-homogeneous, >2 cm, non-healing >2 weeks after irritant removal, or induration/ulceration present.

Squamous cell carcinoma most common intraoral site: lateral border of tongue and floor of mouth; most common oral malignancy overall is SCC (>90%).

Pemphigus vulgaris: IgG against desmoglein 1/3, intraepithelial split, positive Nikolsky sign, suprabasal acantholysis on histology.

Mucous membrane pemphigoid: subepithelial split, linear IgG/C3 at basement membrane; gingival desquamation common; ocular involvement risk requires referral.

Trigeminal neuralgia: paroxysmal lancinating unilateral pain in V2/V3, triggered by touch/chewing; carbamazepine first-line; MRI to exclude secondary causes.

Sjögren syndrome: xerostomia plus xerophthalmia; anti-Ro/SSA and anti-La/SSB; labial salivary gland biopsy focus score ≥1; increased lymphoma risk.

Pulp diagnosis: reversible pulpitis = provoked pain resolving on stimulus removal; irreversible = spontaneous or lingering pain; symptomatic apical periodontitis = tender to percussion with vital or necrotic pulp.

Working length: radiographic estimate minus ~0.5-1.0 mm, confirmed with electronic apex locator; apical constriction typically 0.5-1.0 mm short of radiographic apex.

Canal preparation: crown-down reduces ledging and transportation; sodium hypochlorite 0.5-5.25% dissolves organic tissue; EDTA 17% removes smear layer; final irrigant should not be EDTA alone.

Root canal obturation: warm vertical or carrier-based gutta-percha with sealer; acceptable if filling is 0-2 mm short of radiographic apex with no voids or overextension.

Post-operative flare-up management: occlusal reduction, re-access and re-irrigate if exudate, analgesics; antibiotics not indicated for localized endodontic pain without systemic signs.

Composite bonding: total-etch (37% phosphoric acid, 15 s enamel/15 s dentin) or self-etch; do not etch dentin with phosphoric acid beyond ~15 s to limit collagen collapse.

C-factor (configuration factor) = bonded surface area / unbonded surface area; high C-factor increases polymerization contraction stress; incremental layering reduces stress.

Cuspal coverage: posterior endodontically treated teeth with marginal ridge loss or >50% coronal destruction benefit from onlay/crown; ferrule ≥1.5-2 mm improves fracture resistance.

Rubber dam is standard of care for endodontics; isolation prevents irrigant extrusion and airway aspiration; NaOCl extrusion causes severe pain, swelling, and possible airway compromise.

Complete denture retention factors: adhesion, cohesion, surface tension, atmospheric pressure, and border seal; saliva viscosity affects retention.

Neutral zone: space between lips, cheeks, and tongue where forces are balanced; teeth placed there improve stability of lower complete dentures.

Balanced occlusion in complete dentures: bilateral simultaneous contacts in centric relation and working/non-working side contacts to prevent tipping during excursive movements.

Fixed partial denture abutment selection: crown-to-root ratio ideally ≥1:1; anticipate loss of ~10% support with each additional pontic; avoid pier abutments when possible.

Implant survival criteria: no mobility, no peri-implant radiolucency, <0.2 mm annual bone loss after first year, no pain or neuropathy.

Occlusal vertical dimension assessment: interocclusal rest space 2-4 mm; loss of OVD shows reduced lower face height, angular cheilitis, and commissure drooping.

Removable partial denture design: rests seat on prepared rest seats; avoid soft tissue-borne and tooth-borne conflicting support; major connector should be rigid.

Denture stomatitis: Candida albicans associated, usually palatal erythema under maxillary denture; treat with denture hygiene, overnight removal, and topical antifungal.

Periodontal disease classification: staging (I-IV) reflects severity and complexity (CAL, bone loss, tooth loss); grading (A-C) reflects progression rate and risk factors.

Periodontal health: probing depth ≤3 mm, BOP <10%, no attachment loss; gingivitis = BOP ≥10% with no attachment loss.

CAL = probing depth + recession (or minus hyperplasia); CAL is the reference standard for past attachment loss.

Risk factors modifying periodontitis: smoking (dose-dependent), poorly controlled diabetes (HbA1c >7%), genetics, and stress; smoking masks bleeding and reduces response to therapy.

Non-surgical therapy is first-line: supragingival and subgingival scaling and root planing, oral hygiene instruction, and risk factor control; re-evaluate at 6-8 weeks.

Antibiotics are adjunctive only; systemic amoxicillin plus metronidazole may be considered in grade C/aggressive patterns, never as monotherapy without debridement.

Furcation involvement: Glickman I-IV or Hamp I-III; grade III/IV through-and-through lesions have poorer prognosis and often require tunneling, root resection, or extraction.

Peri-implant mucositis vs peri-implantitis: mucositis = bleeding with no bone loss; peri-implantitis = bleeding plus progressive bone loss; smoking and history of periodontitis increase risk.

Maintenance: recall interval 3-6 months based on risk; residual probing depth ≥5 mm after therapy warrants more frequent monitoring.

Third molar removal indications: recurrent pericoronitis, unrestorable caries, pathology (cyst, tumor), orthodontic need, or prevention of periodontal defect on adjacent second molar.

Inferior alveolar nerve injury risk increases with: lingual or deep impaction, horizontal angulation, proximity to canal on CBCT, and surgeon experience; document consent.

Dry socket (alveolar osteitis): severe pain 2-3 days post-extraction with empty socket and exposed bone; treat with irrigation, medicated dressing; avoid smoking and vigorous rinsing.

Post-extraction bleeding: local measures first (pressure, hemostatic agents, sutures); consider bleeding disorders or anticoagulant status; tranexamic mouthwash may be used.

Mandibular fracture signs: malocclusion, step deformity, paresthesia of lower lip, mobility on manipulation; most common site is angle, then condyle, body, symphysis.

Midface trauma: Le Fort I (low transverse), II (pyramidal), III (craniofacial dysjunction); assess airway, cervical spine, and head injury before facial repair.

Osteoradionecrosis: irradiated bone (>60 Gy) with exposed bone >3 months without healing; hyperbaric oxygen is adjunctive; avoid elective extractions in irradiated fields.

MRONJ: bisphosphonate or antiangiogenic exposure with exposed bone >8 weeks; risk rises with IV agents and duration; conservative management preferred; drug holiday decision is physician-led.

Odontogenic infection spread: submandibular, sublingual, buccal, and canine spaces; Ludwig angina involves bilateral submandibular and sublingual spaces with floor-of-mouth elevation and airway risk, requiring urgent IV antibiotics and drainage.

Eruption timing: first primary tooth ~6 months, primary dentition complete ~2.5-3 years; first permanent molar and mandibular central incisor ~6 years.

Mixed dentition space analysis: arch length discrepancy; leeway space ~1.5 mm per side maxilla, ~2.5 mm per side mandible; E-space larger in mandible.

Class II division 1: increased overjet, proclined maxillary incisors; division 2: decreased overjet, retroclined central incisors with deep bite.

Class III malocclusion: mandibular prognathism or maxillary deficiency; early treatment may use facemask; true skeletal Class III often requires surgery after growth.

Caries risk assessment in children: prior caries, visible plaque, high sugar frequency, enamel defects, and caregiver caries status are key predictors.

Fluoride varnish 5% NaF (22,600 ppm) applied 2-4 times yearly for high-risk children; silver diamine fluoride 38% arrests active dentinal caries.

Pulpotomy vs pulpectomy in primary teeth: pulpotomy for vital pulp with coronal involvement; pulpectomy for irreversibly inflamed or necrotic pulp; avoid formocresol where possible.

Space maintenance: band-and-loop or crown-and-loop for unilateral loss; transpalatal arch or Nance for bilateral; maintain until successor eruption.

Behavior management: tell-show-do, positive reinforcement, and nitrous oxide sedation; restraint requires documented justification and consent.

DMFT/dmft counts decayed, missing, filled permanent/primary teeth; DMFS counts surfaces; higher index values indicate greater caries experience.

Caries prevalence measures: prevalence = existing cases / total population at a time; incidence = new cases / population at risk over time.

Sensitivity vs specificity: sensitivity = true positives / (true positives + false negatives); specificity = true negatives / (true negatives + false positives).

Positive predictive value depends on prevalence; a highly sensitive test is useful for ruling out disease (SnNout), a highly specific test for ruling in (SpPin).

Community water fluoridation optimal level ~0.7 ppm; dental fluorosis risk rises above ~1 ppm; fluoride reduces caries by ~25% in communities.

Plaque control and fluoride toothpaste (1000-1500 ppm) are core preventive measures; high-risk patients may use 5000 ppm fluoride.

Oral health surveys: WHO basic methods use CPI/community periodontal index and DMFT; calibration of examiners improves reliability (kappa >0.8 desirable).

Dental public health planning: needs assessment, priority setting, program implementation, and evaluation; cost-effectiveness favors prevention over treatment.

Screening for oral cancer: visual and tactile examination with risk factor assessment; biopsy confirms diagnosis; no evidence supports population-wide screening alone.

Local anesthetic maximum doses (adult, healthy): lidocaine 2% with epinephrine 7 mg/kg (max ~500 mg, ~13 cartridges); articaine 4% 7 mg/kg; mepivacaine 3% 6.6 mg/kg; bupivacaine 0.5% 1.3 mg/kg.

Epinephrine concentration: 1:100,000 = 0.01 mg/mL; 1:200,000 = 0.005 mg/mL; 1.8 mL cartridge of 1:100,000 contains 0.018 mg epinephrine.

Analgesic dosing: ibuprofen 400-600 mg q6-8h (max 2400 mg/day OTC); paracetamol 500-1000 mg q4-6h (max 4 g/day); avoid aspirin in children under 16 due to Reye syndrome.

Antibiotic prophylaxis for infective endocarditis: amoxicillin 2 g orally 30-60 min before procedure for high-risk cardiac conditions; clindamycin no longer recommended; use cephalexin or azithromycin if penicillin-allergic.

Antibiotic stewardship: antibiotics are not indicated for pulpitis, localized abscess without systemic signs, or routine prophylaxis in prosthetic joints.

Syncope: most common dental emergency; place supine with legs elevated, ensure airway, monitor pulse; recovery is usually rapid.

Anaphylaxis: epinephrine 0.3-0.5 mg IM (1:1000) in adults, repeat every 5-15 min; call emergency services; oxygen and IV fluids as available.

Hypoglycemia: conscious patient gets oral glucose; unconscious patient requires IV dextrose or glucagon; do not give oral fluids if airway unprotected.

Methemoglobinemia: associated with benzocaine and prilocaine; presents with cyanosis unresponsive to oxygen; treat with methylene blue 1-2 mg/kg IV.

Hand hygiene: WHO five moments; alcohol-based hand rub for routine decontamination; soap and water when visibly soiled or after C. difficile exposure.

Sterilization: autoclave 121°C at 15 psi for 15-30 min (gravity) or 134°C for 3-4 min (flash); monitor with biological indicators (Geobacillus stearothermophilus spores) at least weekly.

High-level disinfection for semi-critical items (e.g., some impression trays) using glutaraldehyde or ortho-phthalaldehyde; critical items (surgical instruments) require sterilization.

Sharps safety: do not recap needles by hand; use one-handed scoop or safety devices; dispose in puncture-resistant containers; report needlestick immediately.

Post-exposure prophylaxis: HIV PEP ideally within 2 hours (max 72 hours); hepatitis B immunoglobulin and vaccine if non-immune; document and follow up serology.

Surface disinfection: use EPA-registered hospital disinfectant with tuberculocidal activity for blood-contaminated surfaces; barriers for frequently touched items.

Waterlines: dental unit waterlines should meet ≤500 CFU/mL; flush lines and use independent water reservoirs or filters.

Clinical governance pillars: clinical effectiveness, patient safety, patient experience, and staff development; incident reporting is non-punitive and supports learning.

Record keeping: contemporaneous, legible, signed, dated; retain per local regulation; consent discussions and radiographs documented.

Informed consent requires capacity, disclosure of material risks and alternatives, and voluntary agreement; document the discussion, not just a signature.

Confidentiality: patient information may be disclosed only with consent or where required by law (e.g., notifiable disease reporting, court order, or serious public health risk).

Mandatory reporting in Bahrain: suspected child abuse, communicable diseases of public health importance, and certain occupational injuries must be reported to authorities.

Scope of practice: dentists must practice within licensed scope; prescribing is limited to dental conditions; controlled drugs require adherence to national regulations.

Bahrain dental licensure is regulated by the National Health Regulatory Authority (NHRA); registration and continuing professional development are required to maintain licensure.

Advertising and solicitation: must be truthful, not misleading, and must not disparage colleagues; patient testimonials may be restricted by regulator guidance.

Fitness to practise: impairment from illness, substance misuse, or fatigue must be managed; self-reporting and treatment are expected.

Gifts and conflicts of interest: decline or disclose gifts that could influence clinical decisions; avoid financial incentives that compromise patient care.

Delegation and supervision: dental hygienists and assistants work under dentist supervision per regulation; the dentist retains responsibility for the patient's care.