Membership of the Joint Dental Faculties (MJDF) Operative Dentistry, Endodontics and Prosthodontics Syllabus

State Ante's law and its relevance to bridge design.

Ante's law: the combined root surface area of the abutment teeth should equal or exceed that of the teeth being replaced by the pontics. It guides selecting adequate abutment support, though it is a guideline rather than an absolute rule.

Compare a fixed-fixed bridge with a cantilever bridge.

Fixed-fixed: rigid connectors at both ends with two or more abutments; requires a common path of insertion and shares load. Cantilever: pontic supported at one end only by an abutment; simpler and conservative but creates a leverage/fulcrum and is limited to short spans.

What is a resin-bonded (Maryland) bridge and a key design principle for its success?

A minimally invasive bridge with a metal/zirconia wing bonded to enamel via resin cement. Modern evidence favours a single-retainer (cantilever) design over fixed-fixed to avoid one wing debonding undetected and causing caries; maximal enamel coverage and a defined path of insertion improve retention.

Differentiate addition (PVS/polyvinyl siloxane) from condensation silicone impression materials.

Addition silicone (PVS) sets by addition polymerisation with no volatile by-product, giving excellent dimensional stability and accuracy, and can be poured later. Condensation silicone releases ethanol/water by-product, shrinking over time, so must be poured promptly and is less accurate.

What does the 'putty-wash' two-stage impression technique achieve?

Putty creates a stock-like tray and gross impression; a low-viscosity wash records fine detail under hydraulic pressure, capturing margins accurately while compensating for tray rigidity. Care is needed to provide space/relief so the wash is not displaced unevenly.

List advantages of intraoral digital scanning over conventional impressions.

No impression material/tray discomfort, no setting time or distortion, immediate visualisation and re-scan of deficient areas, easy digital storage and transfer to the lab/CAD-CAM, and reduced disinfection/transport. Limitations include difficulty recording deep subgingival margins and fluid control.

Why must gingival retraction be achieved before recording a subgingival crown margin?

Retraction laterally displaces the gingiva and controls crevicular fluid/haemorrhage, exposing the finish line so the impression material or scanner can capture the full margin and a band of unprepared tooth, ensuring an accurately fitting restoration.

Classify luting cements into their main categories with one example each.

Conventional acid-base: zinc phosphate, glass ionomer. Resin-modified glass ionomer. Resin cements (total-etch, self-etch, self-adhesive). Temporary: zinc oxide eugenol/non-eugenol. Choice depends on retention, aesthetics and substrate.

When is a resin cement preferred over conventional GIC for cementation?

For restorations needing adhesive retention (resin-bonded bridges, veneers, low-retention preparations, fibre posts), aesthetic translucent ceramics, and high-strength bonding to etched/silanated ceramic or zirconia (with MDP primers).

How is a feldspathic/lithium disilicate ceramic surface prepared for resin bonding, and how does this differ for zirconia?

Silica-based ceramics: etch with hydrofluoric acid then apply a silane coupling agent. Zirconia (non-etchable): airborne-particle abrasion (sandblasting) plus an MDP-containing primer/cement, as HF and silane are ineffective.

Define centric relation (CR) in fixed prosthodontics.

Centric relation is the maxillomandibular relationship in which the condyles are in their most anterosuperior position against the posterior slopes of the articular eminences, with the discs interposed; it is a reproducible, ligamentously braced reference position independent of tooth contact.

Distinguish canine-guided occlusion from group function.

Canine guidance: on lateral excursion only the canines contact, discluding posterior teeth (protects them from lateral loads). Group function: multiple teeth on the working side share lateral guidance, distributing load—often used where canines are worn or compromised.

What is anterior guidance and why is it protected during fixed prosthodontic restoration?

Anterior guidance is the influence of contacting anterior teeth on mandibular movement; in protrusion the incisors disocclude the posteriors. Preserving/copying it (e.g. with a custom incisal guide table) protects restorations and the joints from damaging posterior excursive contacts.

Define a working-side (non-functioning?) interference and a balancing-side interference.

A working-side interference is an undesirable contact on the side toward which the mandible moves that disrupts smooth guidance. A balancing-side (non-working) interference is a contact on the opposite side during lateral excursion and is potentially damaging as it acts as a fulcrum.

List the classic clinical features distinguishing reversible from irreversible pulpitis.

Reversible: sharp pain to stimuli (cold/sweet) that stops on removal, no spontaneous pain, normal periapex. Irreversible: spontaneous and/or lingering pain (often to heat, sometimes relieved by cold), may keep patient awake, pulp cannot recover and requires RCT or extraction.

What pulpal and periapical diagnoses are recognised, and what does 'symptomatic apical periodontitis' indicate?

Pulpal: normal, reversible pulpitis, symptomatic/asymptomatic irreversible pulpitis, pulp necrosis, previously treated/initiated. Periapical: normal, symptomatic apical periodontitis (painful to bite/percussion indicating periradicular inflammation), asymptomatic apical periodontitis, acute/chronic apical abscess, condensing osteitis.

Which pulp sensibility tests assess nerve response versus blood supply, and which is more reliable for vitality?

Sensibility tests (cold, electric pulp test) assess nerve (A-delta) response, not true vitality. Blood-supply tests—laser Doppler flowmetry and pulse oximetry—assess actual vascular vitality and are more reliable, especially in recently traumatised/immature teeth, though less commonly available.

State the main objectives of root canal treatment.

To remove pulpal tissue, microorganisms and their substrates (chemomechanical disinfection), shape the canal to a continuously tapering form, and obturate three-dimensionally to seal the canal system, preventing reinfection—followed by coronal restoration.

What is the most common irrigant in endodontics and its principal actions?

Sodium hypochlorite ($\ce{NaOCl}$), typically $1\text{-}6\%$. It is antibacterial and uniquely dissolves organic tissue/biofilm. It is often paired with EDTA to remove the inorganic smear layer.

Why is EDTA used during canal preparation and what concentration is typical?

$17\%$ EDTA is a chelating agent that removes the inorganic component of the smear layer and softens dentine, opening dentinal tubules so irrigants/medicaments penetrate and improving obturation adaptation. It is used as a final rinse, often alternated with NaOCl.

What is the ideal apical extent (working length) of root canal preparation and obturation?

To the apical constriction, approximately $0.5\text{-}1.0\,\text{mm}$ short of the radiographic apex (the minor diameter of the canal), where the canal is narrowest—best confirmed with an electronic apex locator and radiographs.

Describe the goal of vital pulp therapy and name two materials used for direct pulp capping.

Vital pulp therapy aims to maintain pulp vitality after exposure by promoting a dentine bridge and healing. Direct pulp capping materials include hydraulic calcium silicate cements (e.g. MTA, Biodentine) and traditional calcium hydroxide; calcium silicates show superior sealing and outcomes.

How do indirect pulp cap, direct pulp cap and pulpotomy differ?

Indirect pulp cap: caries-affected dentine left over an unexposed pulp and sealed with a biomaterial. Direct pulp cap: a material placed directly onto a small pulp exposure. Pulpotomy: removal of coronal (partial or full) inflamed pulp tissue, leaving vital radicular pulp dressed with a biomaterial.

What is an acute apical abscess and its emergency management?

A localised collection of pus from pulpal necrosis with rapid onset, swelling, severe pain, tenderness to percussion and possible systemic signs. Management: establish drainage (through the canal and/or incision of a fluctuant swelling), remove the source by pulp extirpation/RCT or extraction; antibiotics only if spreading infection or systemic involvement.

What causes an endodontic interappointment flare-up and how is it managed?

Acute pain/swelling between visits, often from apical extrusion of debris/bacteria, microbial imbalance, or over-instrumentation. Management: confirm diagnosis, re-establish drainage, gentle re-irrigation, occlusal relief, analgesics, place calcium hydroxide dressing; antibiotics only with systemic spread.

List common causes of root canal treatment failure necessitating retreatment.

Persistent intracanal/extraradicular infection, missed canals (e.g. MB2), inadequate cleaning/shaping, voids or short/long obturation, coronal leakage from a poor restoration, procedural errors (perforation, ledge, separated instrument), and untreated complex anatomy.

What is an apicectomy (periradicular surgery) and a typical resection/retrofill specification?

Surgical exposure of the root apex, resection of about $3\,\text{mm}$ of the apex (removing most apical ramifications/lateral canals), retrograde cavity preparation (commonly with ultrasonic tips) and a root-end filling (e.g. MTA/biodentine) to seal the canal. Indicated when orthograde retreatment is not feasible or has failed.

Outline the main clinical stages in complete denture construction.

1) Primary impressions (stock trays). 2) Secondary/master impressions (custom trays, border moulding). 3) Jaw registration—record occlusal vertical dimension and centric relation, select teeth. 4) Try-in of waxed-up dentures (aesthetics, occlusion, speech). 5) Processing and fit/delivery, then review/adjustment.

Define occlusal vertical dimension (OVD) and freeway space, and the typical freeway value.

OVD is the face height with teeth in occlusion; rest vertical dimension (RVD) is with the mandible at physiological rest. Freeway space (interocclusal rest space) $= RVD - OVD$, typically about $2\text{-}4\,\text{mm}$. Too little freeway space causes muscle fatigue/clicking teeth; too much causes an over-closed appearance and angular cheilitis.

State the Kennedy classification of partially edentulous arches.

Class I: bilateral free-end saddles (edentulous areas posterior to natural teeth on both sides). Class II: unilateral free-end saddle. Class III: unilateral bounded saddle (teeth anterior and posterior). Class IV: single anterior bounded saddle crossing the midline. Modifications denote additional edentulous spaces (Class IV has none).

Name the four basic components of a removable partial denture framework.

Major connector (joins components across the arch), minor connectors, retainers/clasps (direct retention) plus indirect retainers, and rests (support, directing load along the long axis of abutment teeth). Denture base and artificial teeth complete it.

What is the neutral zone and why is it recorded for complete/edentulous dentures?

The neutral zone is the potential space where the displacing forces of the tongue (inward) balance the cheeks/lips (outward). Positioning teeth and shaping the polished surfaces within it improves denture stability and retention, especially valuable on severely resorbed ridges.

How is centric relation transferred for an edentulous patient, and which articulator feature copies condylar movement?

Wax occlusal rims on record bases are adjusted to correct OVD, then the mandible is recorded in centric relation (e.g. with a registration paste/wax). A facebow transfers the maxilla's relation to the hinge axis; a semi-adjustable articulator with set condylar guidance angles reproduces mandibular movements for tooth setting.

List common causes of a complete denture that lacks retention and stability.

Poor peripheral/border seal, under-extended or over-extended borders, inadequate post-dam, incorrect OVD, teeth set outside the neutral zone, occlusal interferences, a severely resorbed/flat ridge, and xerostomia reducing the saliva film. Diagnosis guides reline, rebase or remake.

What patient/site factors are assessed when selecting a patient for dental implants?

Adequate bone volume/quality and ridge dimensions, sufficient restorative space and inter-arch relationship, healthy soft tissue, controlled systemic health (e.g. diabetes), non-smoking or smoking-cessation, good oral hygiene/periodontal stability, realistic expectations, and absence of uncontrolled parafunction; proximity to vital structures (IAN, sinus, mental foramen) is evaluated, often with CBCT.

Define osseointegration as described by Brånemark.

A direct structural and functional connection between living, ordered bone and the surface of a load-bearing implant, with no intervening fibrous (connective) tissue at the light-microscopic level. Clinically it manifests as a rigid, immobile, asymptomatic fixture.

Compare a cement-retained versus screw-retained implant restoration.

Screw-retained: retrievable, no luting cement (avoids excess-cement peri-implantitis), but needs an accessible/ideally positioned screw channel. Cement-retained: better aesthetics and passivity, usable with angulated implants, but risks residual subgingival cement and is not readily retrievable.

Differentiate peri-implant mucositis from peri-implantitis.

Peri-implant mucositis: reversible inflammation of the peri-implant soft tissue (bleeding on probing, no bone loss). Peri-implantitis: inflammation with progressive supporting bone loss beyond initial remodelling (bleeding/suppuration, increased probing depth and radiographic bone loss), and is the implant analogue of periodontitis.

What are the key risk factors and first-line management of peri-implantitis?

Risk factors: history of periodontitis, poor plaque control, smoking, residual cement, lack of keratinised mucosa, and uncontrolled diabetes. Management: non-surgical debridement/decontamination and oral hygiene reinforcement first; surgical access (resective or regenerative) for persistent/advanced disease, with ongoing supportive maintenance.