LDEK cheat sheet

Pulpitis reversible: sharp pain provoked by cold, resolves within seconds after stimulus removal; histology shows localized inflammation, no necrosis. Irreversible: spontaneous or lingering pain (>30 s after cold), indicative of irreversible pulpal damage requiring root canal therapy.

Lingering cold pain lasting more than 15–30 seconds after stimulus removal is the classic discriminator favoring irreversible pulpitis over reversible pulpitis.

Percussion tenderness signals periapical inflammation (apical periodontitis); a vital, cold-responsive tooth with percussion pain suggests symptomatic apical periodontitis rather than pulpal necrosis.

Normal working length: apical constriction is typically 0.5–1.0 mm short of the radiographic apex; electronic apex locators are accurate within ±0.5 mm in most canals.

Sodium hypochlorite (NaOCl) irrigation: 0.5–5.25% concentration; dissolves necrotic tissue and provides antimicrobial effect. Never extrude beyond the apex - risk of severe tissue damage and nerve injury.

Root canal obturation: gutta-percha with sealer; fill to the apical constriction. Inadequate coronal seal is a major cause of endodontic failure, regardless of apical quality.

Vertical root fracture: suspect with isolated deep probing pocket, J-shaped radiolucency, and pain on biting; extraction is usually required for posterior teeth.

Local anesthesia: inferior alveolar nerve block failure rates up to 15–20% due to accessory innervation or anatomical variation; buccal infiltration with articaine improves success in mandibular molars.

Periodontal disease: probing depth ≥4 mm with bleeding on probing indicates active inflammation; clinical attachment loss, not probing depth alone, defines periodontitis severity.

Antibiotic prophylaxis (AHA 2007/2021): indicated before invasive dental procedures for patients with prosthetic heart valves, prior infective endocarditis, certain congenital heart disease, or cardiac transplant with valvulopathy - not for routine joint prostheses.

Dental caries risk: high risk if ≥1 new cavitated lesion in 3 years, frequent sugar exposure, hyposalivation, or poor plaque control; recall interval should shorten to 3–6 months.

Fluoride varnish (5% NaF, 22,600 ppm) applied 2–4 times/year reduces caries incidence in high-risk patients; do not apply to ulcerated mucosa.

Silver diamine fluoride (38%) arrests active dentin caries and is indicated for uncooperative children or medically fragile adults; causes permanent black staining of carious tissue.

Pulpotomy in primary molars: indicated for vital pulp exposure with controllable hemorrhage; formocresol or MTA are common medicaments. Success decreases with excessive hemorrhage.

Avulsion of permanent tooth: replant immediately within 5 minutes if possible; if dry time >60 minutes, prognosis is poor. Store in Hanks' balanced salt solution, milk, or saline - never water.

Dental trauma luxation: extrusion >3 mm requires repositioning and flexible splint for 2 weeks; intrusion requires orthodontic or surgical repositioning and splinting 4 weeks.

Bisphosphonate-related osteonecrosis of the jaw (MRONJ): exposed bone >8 weeks in a patient on antiresorptive/antiangiogenic therapy with no history of radiation. Avoid elective extractions; conservative management preferred.

Oral potentially malignant disorders: leukoplakia with non-homogeneous appearance has malignant transformation rate of 5–15%; biopsy is mandatory for lesions persisting >2 weeks.

Odontogenic infection spread: submandibular space involvement with dysphagia, trismus, or elevation of floor of mouth requires urgent referral for airway management and IV antibiotics.

Local anesthetic maximum doses: lidocaine 4.4 mg/kg (with epinephrine), articaine 7 mg/kg, mepivacaine 6.6 mg/kg, prilocaine 8 mg/kg; calculate by body weight before administration.

Cementation: resin-modified glass ionomer for zirconia and metal-based restorations; adhesive resin cement for ceramic (lithium disilicate, feldspathic) after hydrofluoric acid etching and silane.

Zirconia requires airborne-particle abrasion with 50 µm alumina and MDP-containing primer for durable resin bonding; hydrofluoric acid does not etch zirconia.

Crown preparation: 1.5–2.0 mm occlusal reduction for metal-ceramic, 1.0–1.5 mm axial reduction; finish line chamfer for metal, shoulder for ceramic margins.

Posterior composite: incremental layering ≤2 mm to ensure adequate polymerization depth; C-factor concerns in Class I cavities favor oblique or bulk-fill techniques.

Occlusal scheme: canine guidance or group function in natural dentition; mutually protected occlusion is the goal in complete dentures.

Complete denture: posterior palatal seal provides retention; border molding captures functional sulcus; balanced occlusion in eccentric movements prevents tipping.

Implant survival: >95% at 10 years for single crowns; risk factors include smoking, uncontrolled diabetes (HbA1c >8%), and history of periodontitis.

Removable partial denture: RPI clasp (mesial rest, proximal plate, I-bar) is preferred for distal extension cases to reduce torque on abutments.

Minimal intervention dentistry: prioritize remineralization and conservative cavity design; sealants for deep pits/fissures in high-caries-risk patients.

Temporization: interim restorations must maintain pulp vitality, occlusal stability, and gingival health; eugenol-containing cements are contraindicated on vital teeth when resin bonding is planned.

Recurrent aphthous stomatitis: minor (≤1 cm, heals in 10–14 days), major (>1 cm, scarring, up to 6 weeks), herpetiform (multiple small ulcers). Treatment: topical corticosteroids.

Oral candidiasis: pseudomembranous form wipes off leaving erythematous base; predisposing factors include inhaled corticosteroids, xerostomia, diabetes, and immunosuppression. First-line: nystatin or fluconazole.

Oral lichen planus: bilateral white striae (Wickham striae) on buccal mucosa; malignant transformation rate 0.5–2%; biopsy recommended for erosive lesions.

Squamous cell carcinoma: most common oral malignancy; lateral tongue and floor of mouth are highest-risk sites. Any ulcer >2 weeks requires biopsy.

Sjögren syndrome: xerostomia, keratoconjunctivitis sicca, and bilateral parotid enlargement; anti-Ro/SSA and anti-La/SSB antibodies; increased lymphoma risk.

Pemphigus vulgaris: intraepithelial acantholysis, positive Nikolsky sign, IgG against desmoglein 1 and 3; treat with systemic corticosteroids.

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

Trigeminal neuralgia: paroxysmal lancinating pain in V2/V3 distribution triggered by touch or chewing; carbamazepine is first-line therapy.

Herpes zoster: unilateral dermatomal vesicles; Ramsay Hunt syndrome involves facial palsy and vesicles in the external auditory canal - urgent antiviral therapy.

Oral submucous fibrosis: areca (betel) nut chewing, progressive trismus; malignant transformation rate up to 7–13%; biopsy any non-healing area.

Eruption timing: first primary tooth at 6–10 months (mandibular central incisor); complete primary dentition by 2.5–3 years; first permanent molar at 6 years.

Early childhood caries (ECC): any caries in children under 6; severe ECC (S-ECC) defined as smooth-surface caries in children under 3. Prevention: fluoride varnish, dietary counseling, twice-daily brushing with 1000 ppm fluoride.

Fluoride toothpaste amount: smear for children under 3, pea-sized for ages 3–6; supervise to minimize swallowing.

Pit-and-fissure sealants: indicated for deep caries-susceptible pits in permanent molars; apply within 2 years of eruption for maximum benefit.

Space maintenance: band-and-loop or crown-and-loop maintain arch length after premature primary molar loss; do not use space maintainers if permanent successor is absent.

Primary tooth pulpectomy: indicated for irreversible pulpitis or necrosis with restorable crown; use resorbable paste (zinc oxide-eugenol or iodoform-based) - do not use gutta-percha in primary teeth.

Natal and neonatal teeth: natal teeth present at birth, neonatal within 30 days; remove only if mobile (risk of aspiration) or causing feeding difficulty.

Molar-incisor hypomineralization (MIH): demarcated opacities on first permanent molars and incisors; management ranges from desensitizing agents to stainless steel crowns depending on severity.

Behavior management: tell-show-do, positive reinforcement, and distraction are first-line; protective stabilization only when less restrictive methods fail and informed consent is obtained.

Fluorosis: enamel hypomineralization from excessive fluoride intake during tooth development (critical period 15–30 months for permanent incisors); mild forms require no treatment.

Epinephrine in local anesthetic: 1:100,000 = 0.01 mg/mL; 1:200,000 = 0.005 mg/mL. Maximum epinephrine dose for healthy adults is 0.2 mg per appointment (approximately 2 cartridges of 1:100,000).

Anaphylaxis: intramuscular epinephrine 0.3–0.5 mg (1:1000) in adults, repeated every 5–15 minutes as needed; call emergency services immediately.

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

Angina pectoris: stop procedure, administer sublingual nitroglycerin 0.3–0.6 mg; if pain persists >15 minutes, suspect myocardial infarction and activate emergency services.

Hypoglycemia: conscious patient - oral glucose; unconscious - IV dextrose or intramuscular glucagon. Diabetic patients should eat before appointments.

Antibiotic prophylaxis regimen (AHA): amoxicillin 2 g orally 30–60 minutes before procedure; clindamycin is no longer recommended due to C. difficile risk - use cephalexin, azithromycin, or doxycycline for penicillin allergy.

NSAIDs (ibuprofen 400–600 mg q6h) are first-line for dental pain; avoid in patients with peptic ulcer disease, renal impairment, or third-trimester pregnancy.

Warfarin: do not stop for routine dental procedures if INR is within therapeutic range (2–3.5); local hemostatic measures (pressure, sutures, tranexamic acid mouthwash) suffice.

Direct oral anticoagulants (DOACs): for low-risk procedures, continue therapy; for high-risk procedures, consider skipping the morning dose - coordinate with the prescribing physician.

Metformin and contrast: withhold metformin if iodinated contrast is used in patients with renal impairment; not relevant to routine dental care but relevant to prescribing decisions.

Periapical radiograph: indicated for evaluating apical pathology, root morphology, and endodontic working length; use paralleling technique with a beam-aiming device for accurate reproduction.

Panoramic radiograph: indicated for evaluating impacted third molars, jaw lesions, and developmental anomalies; not for detecting early caries or subtle periapical lesions.

Cone-beam computed tomography (CBCT): indicated for implant planning, impacted teeth, complex endodontics, and maxillofacial trauma; effective dose is 3–10 times higher than panoramic imaging.

Radiographic caries detection: bitewing radiographs are the gold standard for interproximal caries; lesions must reach 30–40% demineralization to be visible.

Radiolucent lesions: periapical cyst (well-defined, associated with non-vital tooth), ameloblastoma (multilocular, mandibular ramus), odontogenic keratocyst (scalloped margins, high recurrence).

Radiopaque lesions: odontoma (compound or complex), cementoblastoma (attached to root), idiopathic osteosclerosis (dense bone island).

ALARA principle: use the lowest radiation dose achievable; lead apron and thyroid collar for all intraoral radiographs; digital sensors reduce dose by 50–80% compared with film.

Bisphosphonate-related osteonecrosis: radiographic findings include sclerosis, sequestrum formation, and poorly defined margins; correlation with clinical history is essential.

TMJ imaging: panoramic radiograph is initial; CBCT or MRI for disc displacement and degenerative changes; MRI is the gold standard for soft-tissue evaluation.

Caries depth assessment: bitewing radiographs underestimate lesion depth; consider CBCT or clinical evaluation for deep lesions approaching the pulp.