MOH Oral and Dental Health Licensure Exam (Jordan) cheat sheet

Tooth development sequence: initiation (week 6), bud (week 8), cap (weeks 9-10), bell (weeks 11-12), then apposition and maturation. The enamel organ is ectodermal; the dental papilla and follicle are neural-crest ectomesenchyme.

Enamel by weight is about 96% inorganic hydroxyapatite, 1% organic and 3% water. Ameloblasts are lost at eruption, so enamel cannot regenerate or remodel; only demineralization and remineralization occur.

Dentin by weight is about 70% inorganic, 20% organic (mostly type I collagen) and 10% water. Dentinal tubules are 1-2.5 micrometres wide and are more numerous per unit area at the pulp than at the dentinoenamel junction.

Pulp zones from periphery inward: odontoblast layer, cell-free zone of Weil, cell-rich zone, central pulp core. A-delta fibres mediate the sharp, brief dentinal pain; C fibres mediate dull, poorly localized pulpal pain.

Periodontal ligament principal fibre groups: alveolar crest, horizontal, oblique (most numerous; resists axially directed occlusal force), apical and interradicular (multirooted teeth).

Maxillary first permanent molar: three roots, usually three to four canals; the second mesiobuccal canal (MB2) is present in roughly 60-95% of teeth. Mandibular first molar: two roots, three canals (mesiobuccal, mesiolingual, distal).

Primary teeth: enamel only 0.5-1 mm thick, enamel rods in the cervical third incline occlusally (permanent teeth: apically), crowns are bulbous with a marked cervical constriction, proximal contacts are broad and flat, and roots are thin and divergent around the succeeding germ.

Eruption timing: primary mandibular central incisor 6-10 months, primary first molar 12-16 months, primary dentition complete by about 30 months; permanent first molars and mandibular central incisors erupt at about 6 years.

Salivary drainage: parotid (serous) via Stensen's duct opposite the maxillary second molar; submandibular (mixed, mostly serous) via Wharton's duct; sublingual (mucinous) via the ducts of Rivinus and Bartholin.

Leukoplakia is a predominantly white patch that cannot be attributed clinically or histologically to any other disease, so it is a diagnosis of exclusion. Dysplasia is found in roughly 5-25% of biopsies; annual malignant transformation is on the order of 1-3%.

Erythroplakia carries the highest malignant transformation risk of any oral mucosal lesion; biopsy is mandatory.

Oral squamous cell carcinoma accounts for over 90% of oral malignancy; the lateral/ventral tongue and floor of the mouth are the commonest sites. Risk factors include tobacco, alcohol, areca nut and HPV16 (oropharynx). Field cancerization explains second primaries.

Odontogenic keratocyst: parakeratinized lining with a palisaded, hyperchromatic basal layer and satellite cysts; recurrence 20-30%. PTCH1 mutation; multiple keratocysts suggest Gorlin syndrome (basal cell carcinomas, bifid ribs, calcified falx cerebri).

Ameloblastoma is the commonest clinically significant odontogenic tumour, typically in the posterior mandible as a multilocular 'soap-bubble' radiolucency; the unicystic variant occurs in younger patients. Treatment is resection with margins.

Odontoma is the commonest odontogenic tumour overall and is a hamartoma: compound (tooth-like denticles) or complex (amorphous radiopaque mass), both surrounded by a radiolucent halo.

Radicular (periapical) cyst is the commonest odontogenic cyst and is inflammatory, arising from a non-vital tooth. Dentigerous cyst is the commonest developmental cyst and attaches at the cementoenamel junction of an impacted tooth.

Pemphigus vulgaris: IgG against desmoglein 3, suprabasal acantholysis, Nikolsky sign positive, direct immunofluorescence shows intercellular 'net-like' IgG. Mucous membrane pemphigoid: linear IgG/C3 at the basement membrane, subepithelial split, Nikolsky usually negative.

Lesion associations: oral hairy leukoplakia (EBV, lateral tongue, HIV), Kaposi sarcoma (HHV-8), median rhomboid glossitis (Candida), oral submucous fibrosis (areca/betel nut, juxta-epithelial fibrosis, restricted opening), angioedema (ACE inhibitors).

Black's classification: I pits and fissures; II proximal posterior; III proximal anterior with incisal angle intact; IV proximal anterior including the incisal angle; V cervical third of any tooth; VI cuspal tips.

Enamel bevel of about 45 degrees and 0.5-1 mm improves the etch pattern and blends composite margins. Amalgam needs butt-joint cavosurface margins plus mechanical undercut retention; it does not bond to tooth structure.

Etch-and-rinse technique uses 30-40% phosphoric acid, typically 15-30 s on enamel and 15 s on dentin. Self-etch systems leave part of the smear layer and are less technique-sensitive but give lower enamel bond strength.

Composite increments must not exceed 2 mm to ensure adequate depth of cure. C-factor is the ratio of bonded to unbonded surface area; high C-factor cavities (Class I, Class V) develop greater polymerization shrinkage stress and need incremental layering.

Amalgam: high compressive but low tensile and diametral strength; susceptible to creep and corrosion; condens in increments and carve to anatomy with adequate marginal thickness.

Glass ionomer sets by an acid-base reaction between polyacrylic acid and fluoroaluminosilicate glass; it bonds chemically to enamel and dentin and releases fluoride, but has low fracture and wear resistance.

Deep caries management: selective or stepwise removal leaves firm affected dentin over the pulp and seals the cavity with RMGI or composite; re-entry is reserved for symptoms or failure. The aim is to avoid pulpal exposure.

Minimal intervention: ICDAS scoring, sealants for non-cavitated pits and fissures, resin infiltration for white-spot lesions, and 38% silver diamine fluoride to arrest active dentin caries.

Class IV restorations and diastema closure: verify contacts in protrusive and lateral excursions before finishing, and use a palatal silicone key or matrix to build the palatal contour and incisal length.

Working length is 0.5-1.0 mm short of the radiographic apex, corresponding to the apical constriction near the cementodentinal junction; confirm with an electronic apex locator plus a radiograph.

Shaping objectives: a continuously tapered canal (4-8% taper) with an apical preparation of at least ISO size 25 for most canals, patency maintained, and no ledging, transport or perforation.

Sodium hypochlorite 0.5-5.25% is antimicrobial and dissolves tissue; 17% EDTA removes the smear layer. Never mix NaOCl and chlorhexidine in the canal because of precipitation and potential para-chloroaniline formation.

Calcium hydroxide as an intracanal medicament for 1-2 weeks reduces bacterial counts but has limited effect on Enterococcus faecalis and prolonged use may weaken dentin.

Obturation: gutta-percha plus sealer, 0.5-1.0 mm short of working length, adapted three-dimensionally by warm vertical compaction or lateral condensation; place the coronal seal the same visit whenever possible.

Rotary NiTi instruments require a glide path (size 10-15 hand file), torque control and copious irrigation; severely curved, calcified or C-shaped canals carry a higher separation risk.

Pulpal diagnoses: normal, reversible pulpitis, symptomatic irreversible pulpitis, asymptomatic irreversible pulpitis, necrosis. Apical diagnoses: symptomatic apical periodontitis, asymptomatic apical periodontitis, acute apical abscess, chronic apical abscess, condensing osteitis.

Antibiotics are not indicated for irreversible pulpitis or a localized abscess without systemic signs; pulp extirpation and drainage are the definitive treatment. Reserve antibiotics for spreading infection, fever or systemic involvement.

Necrotic immature tooth with an open apex: apexification with an MTA apical plug, or regenerative endodontics (induced blood clot with a Biodentine/MTA coronal seal), which may allow continued root thickening.

Normal sulcus depth is 1-3 mm. Clinical attachment level = probing depth + gingival recession; CAL and percentage radiographic bone loss determine the stage.

2017 staging: Stage I <15% radiographic bone loss; Stage II 15-33%; Stage III >33% with four or fewer teeth lost; Stage IV >33% with five or more teeth lost. Complexity factors such as probing depth 6 mm or more, furcation involvement and vertical defects upgrade the stage.

Grading by rate of progression: percentage bone loss divided by age is <0.25 for Grade A, 0.25-1.0 for Grade B and >1.0 for Grade C. Smoking and HbA1c of 7.0% or more shift the grade upward.

Biologic width is about 2 mm (junctional epithelium about 1 mm plus supracrestal connective tissue about 1 mm). Placing a restoration margin within it causes chronic inflammation and recession.

Non-surgical therapy comes first: scaling and root planing with re-evaluation at 6-8 weeks. Residual pockets of 5 mm or more with bleeding on probing require further active therapy.

Furcation involvement (Glickman I-IV) and tooth mobility (Miller 0-3) refine prognosis; Grade III-IV furcation involvement markedly worsens prognosis and often indicates extraction.

Drug-influenced gingival enlargement is linked to phenytoin, nifedipine/amlodipine and cyclosporine; management is meticulous plaque control plus physician consultation about substitution, with surgery for residual fibrotic tissue.

Adjunctive systemic antibiotics (amoxicillin 500 mg plus metronidazole 400 mg three times daily for 7 days) are reserved for Grade C disease or systemic involvement and are always combined with mechanical debridement.

Peri-implant mucositis is reversible bleeding with no bone loss; peri-implantitis adds progressive bone loss and increasing probing depth. Supportive maintenance every 3-6 months, with risk-based intervals, is the strongest predictor of long-term stability.

Kennedy classification I-IV with Applegate's rules. Class I and II are tooth-tissue supported and require an indirect retainer plus a stress-relieving design such as an RPI/RPA clasp.

Major connectors: maxillary palatal strap, anteroposterior palatal strap or palatal ring; mandibular lingual bar (at least 3 mm tall, 4 mm from the gingival margin) or lingual plate when a bar cannot be used.

Vertical dimension: rest vertical dimension minus occlusal vertical dimension equals the freeway space, normally 2-4 mm. Excessive OVD causes denture soreness; reduced OVD causes angular cheilitis and reduced masticatory efficiency.

Complete denture occlusion should be bilaterally balanced in centric and eccentric positions, with teeth arranged over the residual ridge and within the neutral zone.

Primary stress-bearing areas: mandible - buccal shelf and retromolar pad; maxilla - hard palate and residual ridge. Relief is required over the incisive papilla and midpalatal raphe.

Fixed prosthodontics: Ante's law requires abutment root surface area to equal or exceed that of the teeth replaced; ideal taper 6-10 degrees, minimum 4 mm occlusogingival height, at least 1.5 mm occlusal reduction and a 1.5-2 mm ferrule.

Mutually protected occlusion: anterior guidance discludes the posteriors in excursion, with posterior centric stops. Group function is an alternative when anterior teeth or implants cannot accept the load.

Cement selection: resin cement for zirconia, lithium disilicate and resin-bonded FPDs; RMGI or zinc phosphate for cast metal and PFM where retention is adequate.

Residual ridge resorption is greatest in the first 6-12 months after extraction and continues lifelong; the mandible resorbs about four times faster than the maxilla, moving the denture space progressively buccally and inferiorly.

Inferior alveolar nerve block landmarks: coronoid notch, pterygomandibular raphe, needle parallel to the contralateral premolars, penetration 20-25 mm, 1.5-1.8 mL, aspiration in two planes before injection.

Maximum local anaesthetic doses in a healthy adult: lidocaine 2% with epinephrine 7 mg/kg (not exceeding 500 mg, about 13 cartridges of 1.8 mL); articaine 4% 7 mg/kg (not exceeding 500 mg). Epinephrine limit 0.2 mg in healthy patients and 0.04 mg in cardiac disease.

Third molar assessment: Winter's classification of angulation (mesioangular, distoangular, vertical, horizontal) and Pell-Gregory depth and ramus relationship predict difficulty; CBCT is used when inferior alveolar nerve proximity is suspected.

Odontogenic infection is usually polymicrobial with anaerobes. Treatment is incision and drainage plus amoxicillin-clavulanate or amoxicillin with metronidazole. Admit for airway threat, dysphagia, trismus under 20 mm or floor-of-mouth elevation.

Alveolar osteitis (dry socket) presents 2-4 days after extraction with severe throbbing pain and an empty socket; irrigate and place an obtundent dressing. Antibiotics are not routinely indicated.

Mandibular fractures most often involve the angle, condyle and body. Le Fort I is a low transverse fracture, II is pyramidal, III is craniofacial dysjunction. Airway and cervical spine control precede facial repair.

Infective endocarditis prophylaxis is limited to high-risk cardiac conditions: amoxicillin 2 g orally 30-60 minutes preoperatively; for penicillin allergy use cephalexin, azithromycin or doxycycline rather than clindamycin.

Post-extraction bleeding: firm gauze pressure, local anaesthetic with vasoconstrictor, sutures, haemostatic agents such as oxidised cellulose, and tranexamic acid mouthwash; check INR in warfarin users before further surgery.

TMJ internal derangement: clicking with reduction versus closed lock without reduction. Conservative care (soft diet, NSAIDs, occlusal splint, physiotherapy) precedes arthrocentesis or surgery.

Angle classification uses the first molar relationship: Class I mesiobuccal cusp in the buccal groove; Class II cusp mesial to the groove; Class III cusp distal to it. Class II division 1 has proclined incisors, division 2 retroclined incisors with deep bite.

Cephalometric norms: SNA 82 degrees, SNB 80 degrees, ANB 2 degrees; FMA 25 degrees; GoGn-SN about 32 degrees. ANB above 4 degrees suggests skeletal Class II; ANB below 0 degrees suggests skeletal Class III.

Leeway space is about 0.9 mm per maxillary side and 1.7 mm per mandibular side; it can resolve mild mixed-dentition crowding using a lower lingual holding arch or lip bumper.

Bolton analysis: anterior ratio about 77.2% and overall ratio about 91.3%; a discrepancy means tooth-size imbalance, managed by extraction, interproximal reduction or addition.

Anchorage sources: extraoral (headgear, face mask), intraoral (transpalatal arch, Nance appliance, lip bumper) and skeletal (miniscrews/TADs). Maximum anchorage requires reinforcing the posterior segments.

Biologically efficient tooth movement needs light continuous force, roughly 50-150 g for translation and retraction; heavy force causes hyalinization and root resorption rather than faster movement.

Functional appliances (Twin Block, activator, Herbst) advance the mandible in growing Class II patients; face mask protraction is used for growing Class III patients with maxillary deficiency.

Retention: Hawley or vacuum-formed removable retainer plus bonded lingual 3-3. Mandibular anterior crowding relapses most, so long-term or lifelong retention is common.

White-spot decalcification around brackets is prevented by oral hygiene, fluoride varnish and reduced sugar frequency; existing lesions may be managed by infiltration or remineralization.

Primary dentition: 20 teeth. First eruption is the mandibular central incisor at 6-10 months and the dentition is complete by about 30 months. First dental visit is recommended by the first birthday or first tooth.

Primary tooth features: enamel 0.5-1 mm thick, thin dentin, large pulp horns, marked cervical constriction, flat proximal contacts and divergent roots enclosing the permanent tooth germ.

Early childhood caries: any caries in a child under 6 years. Severe ECC means smooth-surface caries or any caries in a child under 3 years. Risk factors include night-time bottle feeding, frequent sugar and enamel defects.

Early intervention: 5% sodium fluoride varnish every 3-6 months, 38% silver diamine fluoride to arrest active dentin caries, and sealants on caries-free erupted first permanent molars.

Pulp therapy in primary teeth: pulpotomy (formocresol, ferric sulfate or MTA) for vital exposure; pulpectomy with a resorbable paste for irreversible pulpitis. Avoid overextending paste beyond the apex.

Stainless steel crowns are indicated for multi-surface caries, after pulpotomy, in hypoplasia and in high caries-risk children. The Hall technique cements a crown over the untreated lesion without anaesthesia or preparation.

Space management: band and loop after premature loss of a primary first molar; lower lingual holding arch or Nance appliance to preserve leeway space and arch length.

Avulsed permanent tooth: handle by the crown, replant immediately if possible, or store in milk or HBSS, then flexible splint for about 2 weeks. An avulsed primary tooth is never replanted.

Local anaesthesia in children: lidocaine 2% at 4.4 mg/kg (maximum about 300 mg); articaine 7 mg/kg. Use a small-gauge needle, warm the solution and inject slowly with behaviour guidance such as tell-show-do.

Amalgam contains roughly 50% mercury with silver, tin and copper; compressive strength is high but tensile strength low. Failure modes are marginal ditching, secondary caries and tooth fracture. Available evidence does not show harm from dental amalgam except in allergy.

Composite: resin matrix (Bis-GMA, TEGDMA, UDMA) with silane-treated filler; volumetric shrinkage 2-3%; camphorquinone is activated at 400-500 nm; increments of 2 mm or less with adequate irradiance ensure conversion.

Bonding generations: fourth = 3-step etch-and-rinse, fifth = 2-step etch-and-rinse, sixth and seventh = self-etch. Enamel bond strength generally exceeds dentin bond strength, and etch-and-rinse dentin should remain moist.

Glass ionomer sets by an acid-base reaction between polyacrylic acid and fluoroaluminosilicate glass, releasing fluoride and bonding chemically; resin-modified GI adds resin for strength.

Calcium hydroxide (pH about 12.5) and MTA (tricalcium silicate, sets in about 3-4 hours) are used for pulp capping and apexification. Zinc oxide eugenol is an obtundent liner but inhibits resin polymerization.

Impression materials: addition silicone (PVS) is the most dimensionally stable and can be poured more than once; polyether is stiff and hydrophilic for wet fields; alginate is an irreversible hydrocolloid that must be poured promptly because of syneresis and imbibition.

Gypsum products: Type II plaster for models, Type III dental stone for casts, Type IV die stone (high strength, low expansion) for dies, Type V high-expansion stone for denture processing.

Analgesic dosing: ibuprofen 400-600 mg every 6-8 hours (maximum 2400 mg/day without supervision); paracetamol 500-1000 mg every 4-6 hours (maximum 4 g/day in adults). Aspirin is avoided in children because of Reye syndrome.

Local anaesthetic pharmacology: lidocaine is an amide metabolised hepatically; articaine is metabolised by plasma esterases and has higher reports of paraesthesia; bupivacaine 0.5% acts 8-12 hours and is more cardiotoxic; prilocaine can cause methaemoglobinaemia.

Caries indices: DMFT/dmft counts teeth, DMFS/dmfs counts surfaces; the care index is filled teeth divided by total caries experience and reflects treatment provision rather than need.

Plaque and gingival indices: Silness-Loe plaque index (0-3), O'Leary plaque control record (percentage of surfaces), Loe-Silness gingival index (0-3); CPITN/CPI codes each sextant 0-4.

Screening statistics: sensitivity = TP/(TP+FN); specificity = TN/(TN+FP); positive predictive value = TP/(TP+FP). Predictive values depend on disease prevalence, so they vary between populations.

Fluoride acts mainly topically through remineralization, fluorapatite formation and bacterial enzyme inhibition; community water fluoridation at about 0.7-1.0 mg/L is the classic population-level measure.

Professional fluoride: 5% sodium fluoride varnish (22,600 ppm) two to four times yearly for high-risk patients; 1.23% APF gel; 0.2% sodium fluoride weekly rinse in school programmes; 0.05% daily rinse for adults.

Levels of prevention: primary (fluoride, sealants, education), secondary (screening, early restoration), tertiary (rehabilitation, prostheses, disability limitation).

Sealants are resin-based and indicated for deep pits and fissures in high-risk patients; retention of the sealant is the main determinant of effectiveness.

Behaviour-change models: Health Belief Model, Theory of Planned Behaviour and the Transtheoretical model (precontemplation through maintenance); the 5 A's structure tobacco cessation counselling.

Study designs: cross-sectional for prevalence, cohort for incidence and risk, case-control for rare outcomes, and randomized controlled trials for interventions; systematic reviews and RCTs sit highest in the evidence hierarchy.

Standard precautions apply to every patient regardless of known diagnosis; all blood, saliva and gingival fluid are treated as potentially infectious.

Hand hygiene: alcohol-based hand rub for routine procedures, soap and water when visibly soiled; follow the WHO five moments, and perform hygiene before gloving and immediately after degloving.

Spaulding classification: critical items (surgical, periodontal, endodontic instruments) require sterilization; semi-critical items (mirrors, impression trays, handpieces) require sterilization or high-level disinfection; non-critical items (light handles, chair surfaces) require low-level disinfection.

Steam sterilization parameters: 121 degrees C at 15 psi for 15-30 minutes (gravity displacement) or 132-134 degrees C for 3-4 minutes (Class B vacuum); dry heat 160 degrees C for 2 hours.

Biological monitoring at least weekly and with each load: Geobacillus stearothermophilus for steam sterilizers, Bacillus atrophaeus for dry heat and ethylene oxide; a positive result requires quarantine and recall of the load.

Instruments must be cleaned and dried before sterilization (ultrasonic cleaner or washer-disinfector), pouched with an internal chemical indicator, not overloaded in the chamber, and stored in closed cabinets.

Surface disinfection uses an intermediate-level disinfectant; for blood spills use 0.5% sodium hypochlorite (1:10 dilution of 5.25% household bleach) with about 10 minutes contact time. Use barriers on high-touch surfaces.

Sharps safety: never recap with two hands; use a one-handed scoop or needle destroyer; fill sharps containers to no more than three-quarters. Post-exposure transmission risk is about 0.3% for HIV, up to 30% for hepatitis B and about 1.8% for hepatitis C.

Dental unit waterlines: flush 20-30 seconds at the start of the day and between patients; maintain output at or below 500 CFU/mL with independent reservoirs, filters or antimicrobial treatment. Rubber dam and high-volume evacuation reduce aerosols.

Informed consent requires capacity, adequate disclosure (diagnosis, options, risks, benefits, consequence of no treatment), comprehension and voluntariness, and must be documented in the record before treatment begins.

Four ethical principles: autonomy (patient's informed choice), beneficence (act in the patient's interest), non-maleficence (avoid harm), justice (fair treatment and resource allocation); veracity and confidentiality support these.

Confidentiality may be breached only with patient consent, where required by law (for example notifiable disease or child protection), or where there is serious risk to the patient or public; disclose the minimum necessary.

Syncope is the commonest medical emergency in dental practice: lay the patient supine with legs elevated, ensure airway patency, give oxygen and monitor. Anaphylaxis requires epinephrine 0.5 mg intramuscularly (1:1000) in the mid-outer thigh, repeated every 5 minutes as needed.

Emergency kit essentials: oxygen, epinephrine, diphenhydramine, glyceryl trinitrate, salbutamol, oral glucose or glucagon, aspirin, naloxone, flumazenil and an automated external defibrillator.

Scope of practice: refer when care exceeds competence. Abandonment occurs when treatment is withdrawn without reasonable notice, so give written notice, offer transfer options and provide emergency cover.

Clinical records must be contemporaneous, dated, signed and factual; never alter entries retrospectively. Retain records for the period required by local regulation.

Radiation safety follows ALARA: lead apron and thyroid collar, rectangular collimation, fastest receptor available. Occupational dose limit is 20 mSv per year averaged over five years; public limit is 1 mSv per year.

Patient safety: disclose adverse events and near misses to the patient, document them, report through the incident system and analyse root causes. The WHO surgical safety checklist and pre-procedure site verification prevent wrong-site extraction.