EHPLE Dental Medicine cheat sheet

Enamel is 96% mineral by weight, avascular, and cannot regenerate; ameloblasts are lost after eruption, so caries and wear are irreversible.

Dentin: ~70% mineral, 20% organic (mostly type I collagen), 10% water; dentinal tubules run from pulp to DEJ, S-shaped in coronal dentin, straighter in root dentin.

Permanent molars: mandibular first molar has 5 cusps and 2 roots; maxillary first molar has 4 cusps plus cusp of Carabelli and 3 roots (MB, DB, palatal).

Primary teeth are whiter, have thinner enamel, larger pulps, more bulbous crowns, and pronounced cervical constriction; roots flare to accommodate permanent successors.

Nerve supply: maxillary teeth via posterior, middle, and anterior superior alveolar nerves (V2); mandibular teeth via inferior alveolar nerve (V3), with mental nerve supplying premolars and incisors.

Saliva: resting flow ~0.3 mL/min, stimulated ~1.5-2 mL/min; pH 6.7-7.4; bicarbonate is the main buffer; submandibular gland contributes ~65-70% of unstimulated flow.

Periodontal ligament fibers: principal groups are alveolar crest, horizontal, oblique (most numerous, resists axial load), apical, and interradicular.

Temporomandibular joint is a bilateral, synovial, ginglymoarthrodial joint with a fibrocartilaginous disc; lateral pterygoid initiates opening and translates the condyle.

Leukoplakia is a clinical diagnosis of exclusion (white patch not attributable to another disease); dysplasia on biopsy determines malignant potential, not the clinical appearance.

Erythroplakia carries a much higher risk of dysplasia or carcinoma than leukoplakia; any persistent red patch warrants biopsy.

Aphthous ulcers are recurrent, painful, non-keratinized mucosal ulcers with a yellow fibrin center and erythematous halo; they heal in 7-14 days without scarring (major aphthae may scar).

Oral lichen planus: bilateral white striae (Wickham striae) on buccal mucosa, T-cell-mediated; erosive forms carry a small malignant transformation risk and need follow-up.

Odontogenic cysts: radicular (periapical) cyst is the most common inflammatory cyst; dentigerous cyst surrounds the crown of an unerupted tooth; keratocyst (OKC) has high recurrence.

Ameloblastoma is a locally aggressive odontogenic tumor, most often in the posterior mandible, with a soap-bubble radiolucency; treatment is resection with margins.

Squamous cell carcinoma of the tongue lateral border and floor of mouth is the most common intraoral malignancy; risk factors include tobacco, alcohol, and HPV (oropharyngeal).

Oral candidiasis: pseudomembranous form wipes off leaving erythema; angular cheilitis and denture stomatitis are chronic forms; treat with topical nystatin or miconazole, or systemic fluconazole.

Caries is a pH-driven process: demineralization occurs below a critical pH of ~5.5 for enamel and ~6.2 for dentin; fluoride lowers the critical pH and promotes remineralization.

DMFT index counts decayed, missing, and filled permanent teeth; dmft is the primary-dentition equivalent.

Cavity classification (G.V. Black): Class I pits/fissures, II proximal posterior, III proximal anterior without incisal edge, IV proximal anterior with incisal edge, V cervical.

Composite bonding: total-etch (phosphoric acid 30-40%) or self-etch; enamel etching improves seal; dentin must remain moist for total-etch to avoid collagen collapse.

Amalgam has no adhesive bond and requires mechanical retention; do not place in contact with a cast restoration of a different metal (galvanic corrosion).

Glass ionomer releases fluoride, bonds chemically to tooth, and is used for pediatric and cervical restorations and as a base; it is moisture-sensitive during set.

Shade selection should be done before dehydration, under daylight or corrected lighting, with the tooth moist; enamel is more translucent than dentin.

Cusp coverage (onlay) is indicated when remaining cuspal thickness is less than about 2 mm or when the isthmus width exceeds one-third of the intercuspal distance.

Working length is typically 0.5-1.0 mm short of the radiographic apex; the apical constriction is the ideal reference point.

Electronic apex locators work on impedance/resistance changes and remain accurate in the presence of blood or exudate, but not with metallic restorations contacting the file.

Irrigants: sodium hypochlorite (0.5-5.25%) dissolves organic tissue and is antimicrobial; EDTA (17%) removes the smear layer; chlorhexidine is an alternative but must not be mixed with NaOCl (precipitate).

Canal preparation: crown-down technique reduces coronal interference and improves irrigant penetration; apical size should be at least 25-30 in most canals.

Pulpal diagnoses: reversible pulpitis (provoked pain, resolves), irreversible pulpitis (spontaneous or lingering pain), necrotic pulp (no response), previously treated.

Periapical diagnoses: symptomatic apical periodontitis (pain on biting), asymptomatic apical periodontitis (radiolucency, no symptoms), acute apical abscess (swelling, systemic signs), chronic apical abscess (sinus tract).

Root canal obturation: gutta-percha with sealer; the sealer fills accessory canals and irregularities; extrusion of sealer beyond the apex may cause a flare-up.

Vertical root fracture presents with a deep, narrow pocket, J-shaped radiolucency, and pain on biting; the tooth is generally not restorable and requires extraction.

Gingivitis is reversible inflammation confined to the gingiva, with no attachment loss; periodontitis involves clinical attachment loss and alveolar bone loss.

Probing depth is measured from the gingival margin to the sulcus base; clinical attachment level = probing depth + recession (or minus hyperplasia).

2018 classification uses staging (I-IV, severity and complexity) and grading (A-C, rate of progression) based on interdental CAL, bone loss, and risk factors such as smoking and diabetes.

Bleeding on probing indicates inflammation; its absence has a high negative predictive value for stability.

Scaling and root planing is the initial therapy for periodontitis; re-evaluation occurs 6-8 weeks later, and surgery is considered for residual pockets of 5 mm or more with bleeding.

Risk factors: smoking (dose-dependent), poorly controlled diabetes, genetic predisposition, and medications (phenytoin, nifedipine, cyclosporine cause gingival overgrowth).

Regeneration (guided tissue regeneration, bone grafts) is indicated for intrabony defects and furcation involvement, not for suprabony horizontal bone loss.

Maintenance: recall intervals of 3-6 months depending on risk; supportive periodontal therapy reduces recurrence and tooth loss.

Occlusal vertical dimension can be assessed by resting tongue space, interocclusal rest space of 2-4 mm, and phonetic tests (closest speaking space ~1-2 mm).

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

Fixed partial denture abutment selection: crown-root ratio ideally at least 1:1; antierior (Ante's) law requires combined root surface area of abutments to equal or exceed the replaced tooth.

Implant osseointegration requires primary stability and a blood clot free of micromotion (less than ~50-150 micrometers); healing is 3-6 months depending on bone quality.

Implant success criteria: no mobility, no peri-implant radiolucency, bone loss less than 0.2 mm per year after the first year, and no pain or neuropathy.

Peri-implant mucositis is reversible inflammation with no bone loss; peri-implantitis adds progressive bone loss and requires decontamination plus surgical or nonsurgical therapy.

Residual ridge resorption is greatest in the first year after extraction and continues faster in the mandible; the mandibular ridge resorbs in a downward and outward direction.

Occlusal scheme for implant-supported restorations: narrower occlusal tables, flatter cusps, and elimination of working/nonworking interferences reduce overload.

Third molar extraction difficulty increases with root curvature, depth of impaction (Pell-Gregory), bone density, and proximity to the inferior alveolar canal.

Inferior alveolar nerve injury risk is highest for deeply impacted mandibular third molars with roots overlapping the canal on panoramic imaging; CBCT clarifies the relationship.

Dry socket (alveolar osteitis) presents 2-4 days after extraction with severe throbbing pain and an empty socket; treatment is irrigation and a medicated dressing, not antibiotics.

Postoperative bleeding is controlled by pressure and local hemostatic agents; persistent bleeding requires checking INR in patients on warfarin and platelet count if on antiplatelets.

Orthognathic surgery: Le Fort I osteotomy moves the maxilla; bilateral sagittal split osteotomy (BSSO) moves the mandible; genioplasty corrects chin position.

Odontogenic infection spreads along fascial planes; submandibular and sublingual spaces communicate via the mylohyoid muscle, and Ludwig's angina is a bilateral floor-of-mouth cellulitis requiring airway management.

Biopsy principles: incisional biopsy for large or suspicious lesions, excisional for small lesions; never biopsy a suspected vascular lesion without imaging.

Antibiotic prophylaxis before dental surgery is indicated for prosthetic heart valves, previous infective endocarditis, and certain congenital heart disease, per current guidelines.

Angle classification: Class I has a normal first molar relationship; Class II has the mandibular molar distal to the maxillary; Class III has the mandibular molar mesial.

Cephalometric landmarks: SNA measures maxillary position relative to the cranial base, SNB measures mandibular position, and ANB reflects the skeletal jaw relationship (normal ~2-4 degrees).

Growth modification: functional appliances and headgear work best during the pubertal growth spurt; timing is assessed by cervical vertebral maturation or hand-wrist radiographs.

Arch expansion and extraction decisions depend on arch length discrepancy, profile, and crowding; premolar extraction is common for severe crowding and bimaxillary protrusion.

Clear aligners are effective for mild-to-moderate crowding and spacing; complex rotations and severe skeletal discrepancies are better treated with fixed appliances.

Anchorage: maximum anchorage requires minimizing anterior retraction of posterior teeth, using palatal or skeletal anchorage (miniscrews) when needed.

Retention after orthodontics is lifelong in many cases; relapse risk is highest in the first year and with rotational and expansion movements.

Impacted canines: CBCT localizes the tooth; surgical exposure with orthodontic traction is preferred when the tooth is restorable and the arch has space.

Eruption timing: first primary tooth at 6-10 months, complete primary dentition by 2.5-3 years, first permanent molar at 6 years, and mixed dentition until about 12 years.

Nursing bottle caries (early childhood caries) affects maxillary incisors first, sparing mandibular incisors because of tongue protection and salivary flow.

Fluoride varnish (5% NaF) is applied every 3-6 months for caries prevention; systemic fluoride supplements are indicated only for children in low-fluoride areas.

Pulpotomy is indicated for a vital pulp with coronal inflammation; pulpectomy is used when the radicular pulp is involved; stainless steel crowns restore badly broken primary molars.

Space maintenance: a band-and-loop or crown-and-loop maintains space after premature loss of a primary molar; a lingual arch maintains arch length after loss of primary incisors.

Behavior management: tell-show-do, positive reinforcement, and distraction are first-line; protective stabilization and sedation are reserved for specific indications with consent.

Local anesthesia in children: maximum lidocaine dose is about 4.4 mg/kg (2.2 mg/kg with epinephrine in some guidelines); calculate by weight before injection.

Trauma in primary teeth: intruded primary teeth are often left to re-erupt if not displaced into the permanent germ; avulsed primary teeth are not replanted.

Periapical radiographs show the entire tooth and at least 2-3 mm of periapical bone; bitewings show crowns and alveolar crests for caries and bone level assessment.

Paralleling technique reduces distortion; bisecting-angle technique is used when paralleling is not possible, but it magnifies the image.

Radiolucent lesions: caries, periapical granuloma or cyst, and ameloblastoma appear dark; radiopaque lesions include amalgam, enamel, and odontoma.

Panoramic radiography has lower resolution and more magnification than intraoral films; it is a screening tool, not a substitute for periapical imaging.

CBCT provides 3D imaging with lower dose than medical CT; it is indicated for implant planning, impacted teeth, and complex endodontic anatomy.

ALARA principle: use the lowest dose that achieves the diagnostic goal; collimate the beam, use rectangular collimation, and avoid repeat exposures.

Radiographic signs of malignancy: ill-defined borders, root resorption, widening of the periodontal ligament space, and rapid growth.

Digital sensors reduce dose compared with film; image processing (contrast, brightness) can improve visibility but cannot create information not captured.

Local anesthetics: lidocaine 2% with 1:100,000 epinephrine gives about 60 minutes of pulpal anesthesia; articaine 4% has higher lipid solubility and bone penetration.

Maximum doses: lidocaine 4.4 mg/kg (max 300 mg), articaine 7 mg/kg (max 500 mg), mepivacaine 6.6 mg/kg (max 400 mg), and prilocaine 8 mg/kg (max 600 mg).

Epinephrine contraindications are relative: caution in uncontrolled hypertension, recent myocardial infarction, and hyperthyroidism; 1:100,000 is generally safe.

Antibiotics: amoxicillin 500 mg three times daily is first-line for odontogenic infections; penicillin allergy calls for clindamycin or azithromycin; metronidazole covers anaerobes.

Analgesics: NSAIDs (ibuprofen) are first-line for dental pain; paracetamol is an alternative; avoid aspirin in children due to Reye syndrome.

Anticoagulants: do not stop warfarin for routine dental care if INR is therapeutic; local hemostatic measures suffice; direct oral anticoagulants may require timing coordination.

Bisphosphonate-related osteonecrosis of the jaw: risk increases with intravenous and long-term oral use; avoid elective extractions when possible and obtain informed consent.

Drug interactions: erythromycin and azole antifungals inhibit CYP3A4 and raise levels of some drugs; metronidazole plus alcohol causes a disulfiram-like reaction.

Syncope is the most common dental emergency; management is supine position, legs elevated, airway maintenance, and monitoring of pulse and breathing.

Anaphylaxis: intramuscular epinephrine 0.3-0.5 mg (1:1000) in adults, repeat every 5-15 minutes; call emergency services and give oxygen.

Local anesthetic overdose presents with excitation, tremor, and seizures followed by CNS depression; management is airway support and benzodiazepines for seizures.

Aspiration of a foreign object: encourage coughing if the patient can cough; if not, perform abdominal thrusts (Heimlich) and call for help.

Hypoglycemia in a diabetic patient: give oral glucose if conscious, glucagon or intravenous dextrose if unconscious; monitor and call emergency services.

Basic life support: compression rate 100-120 per minute, depth 5-6 cm in adults, ratio 30:2 with rescue breaths; use an AED as soon as available.

Vasovagal reaction versus local anesthetic toxicity: syncope is bradycardic and pale; toxicity is tachycardic with CNS excitation.

Emergency kit essentials: epinephrine, oxygen, aspirin, nitroglycerin, glucose, and a bronchodilator, with regular expiry checks.

Informed consent requires disclosure of diagnosis, treatment options, risks, benefits, and alternatives, plus the patient's voluntary agreement; it is a process, not just a signature.

Confidentiality: patient information may be disclosed only with consent or when required by law (e.g., reporting infectious disease or suspected abuse).

Record keeping: retain clinical records for the period required by local law; accurate, contemporaneous notes are the best defense in litigation.

Scope of practice: a dentist may delegate only tasks permitted by law and must supervise auxiliary personnel according to regulation.

Infection control: standard precautions apply to all patients; hand hygiene, PPE, and sterilization of instruments are mandatory; sharps must be disposed of in designated containers.

Advertising and professional conduct: avoid misleading claims and guarantee language; maintain patient dignity and avoid disparaging colleagues.

Practice management: fee setting should reflect costs and market rates; billing must be accurate and documented; insurance claims must match clinical records.

Mandatory reporting: suspected child abuse, certain communicable diseases, and adverse events may require reporting under local law.