NEET MDS Conservative Dentistry Syllabus

What is the role of the silane coupling agent in composites?

It chemically bonds the inorganic filler particles to the organic resin matrix, improving strength and preventing filler dislodgement.

What is polymerization shrinkage and why does it matter?

The volumetric contraction (~2–5%) of resin composite during curing; it creates stress that can cause marginal gaps, microleakage, and postoperative sensitivity.

What is the C-factor (configuration factor)?

The ratio of bonded to unbonded (free) surfaces in a cavity; a higher C-factor means greater polymerization shrinkage stress on the bond.

State the setting reaction type of conventional glass ionomer cement.

An acid-base reaction between fluoroaluminosilicate glass powder and polyacrylic acid liquid, forming a cross-linked polysalt matrix.

Name two key advantages of glass ionomer cement.

Chemical (true) adhesion to tooth structure and sustained fluoride release (anticariogenic); also biocompatible with a thermal expansion similar to tooth.

Name and number Black's classification of cavities (Class I–V).

I: pits/fissures; II: proximal of posteriors; III: proximal of anteriors (no incisal); IV: proximal of anteriors with incisal angle; V: cervical/gingival third of all teeth (Class VI: incisal edges/cusp tips).

What are the main steps/components of cavity preparation (Black's outline)?

Outline form, resistance form, retention form, convenience form, removal of carious dentin, finishing of enamel walls/margins, and toilet (cleaning) of the cavity.

Differentiate resistance form and retention form.

Resistance form enables the restoration/tooth to withstand occlusal forces without fracture; retention form prevents displacement/dislodgement of the restoration.

Why does an amalgam cavity require a flat pulpal floor and ~90° cavosurface margin?

Amalgam is brittle and strong in compression; a flat floor distributes forces and a butt-joint (90°) margin gives bulk to resist fracture at the margin.

How does composite cavity design differ from amalgam design?

Composite needs no specific retentive form (it bonds), allows conservative/rounded internal preparation, and uses a beveled enamel margin to increase bonding surface and esthetics.

What is the function of a bevel in cavity preparation?

It exposes enamel rod ends for better acid-etch bonding, increases surface area, improves marginal seal and esthetic blend (used with composites/gold).

Name the basic categories of hand cutting instruments.

Cutting (chisels, hatchets, hoes, gingival margin trimmers, excavators) and the formula is described by Black's instrument formula (3 or 4 numbers).

What do the numbers in Black's three-number instrument formula represent?

1st = blade width (0.1 mm); 2nd = blade length (mm); 3rd = blade angle relative to the long axis of the handle (centigrades, 1/100 of 360°).

What is the principal advantage of amalgam over composite in posterior teeth?

Superior durability/wear resistance, lower technique sensitivity, lower cost, and better performance in moisture-contaminated or large stress-bearing situations.

What is the total-etch (etch-and-rinse) technique?

Application of 30–40% phosphoric acid to etch enamel and dentin simultaneously, removing the smear layer, followed by primer/adhesive before composite placement.

What is a self-etch adhesive?

An adhesive using acidic monomers that simultaneously etch and prime dentin/enamel without a separate rinse step, incorporating the smear layer.

What is the recommended incremental thickness for light-cured composite and why?

≤2 mm increments to ensure adequate depth of cure and to reduce polymerization shrinkage stress (except for bulk-fill composites).

What is the indication difference among Type I, II, and III GIC?

Type I: luting/cementation; Type II: restorative (esthetic and reinforced); Type III: liners/bases and fissure sealants.

Define inlay and onlay.

An inlay is an indirect intracoronal restoration fitting within cusps; an onlay is an indirect restoration that covers one or more cusps (extracoronal coverage of cusp tips).

When is full-coverage crown indicated over a direct restoration?

For extensively damaged/endodontically treated teeth, large old restorations, cuspal fracture, or when significant strength/protection and esthetics are required.

What is a dental veneer and its two types?

A thin layer of restorative material covering the labial surface for esthetics; types are direct (composite, chairside) and indirect (porcelain/ceramic, lab-fabricated).

What is reversible pulpitis and its hallmark symptom?

Mild, reversible pulpal inflammation; sharp pain to stimuli (cold/sweet) that subsides quickly when the stimulus is removed; pulp recovers if the irritant is removed.

How is irreversible pulpitis distinguished clinically from reversible pulpitis?

Irreversible pulpitis gives spontaneous, lingering pain (lasting after stimulus removal), often worse with heat and on lying down; it requires root canal treatment or extraction.

What differentiates acute apical periodontitis from a periapical abscess?

Apical periodontitis is inflammation of the periodontal ligament at the apex (tender to percussion); a periapical (alveolar) abscess is a localized purulent (pus) collection with swelling.

What are the objectives of root canal treatment?

Thorough cleaning and shaping (chemo-mechanical debridement), disinfection, and three-dimensional obturation of the canal system to prevent reinfection.

What is the most common irrigant in endodontics and its action?

Sodium hypochlorite (NaOCl, 1–5.25%); it dissolves organic/necrotic tissue and is a potent antimicrobial; EDTA is used to remove the inorganic smear layer.

What is the gold-standard core obturating material and its sealer partner?

Gutta-percha as the core material, used with a root canal sealer (e.g., zinc oxide-eugenol, resin, or bioceramic sealer).

How is a 'hot tooth' (acute irreversible pulpitis) emergency managed?

Achieve profound anesthesia (supplemental intraligamentary/intrapulpal), perform pulpotomy or pulpectomy to remove inflamed tissue and relieve pain.

What are the principles/elements of esthetic (smile) design?

Tooth shade/color, shape and proportion (golden proportion), symmetry, midline alignment, incisal edge position, gingival contour/health, and lip framing.

What are the main vital tooth bleaching techniques?

In-office (high-concentration hydrogen peroxide, often light/heat activated) and at-home (low-concentration carbamide peroxide in custom trays).

What active agents are used in tooth bleaching and how do they work?

Hydrogen peroxide and carbamide peroxide; they release free radicals (reactive oxygen) that oxidize and break down chromogenic (stain) molecules in the tooth.

Name Ellis classification classes for crown/tooth fractures (1–3).

Class 1: enamel only fracture; Class 2: enamel + dentin (no pulp exposure); Class 3: enamel + dentin + pulp exposure (Ellis extends to 9 covering root/displacement/avulsion).

What is the emergency management of an avulsed permanent tooth?

Replant immediately if possible; otherwise store in a physiologic medium (HBSS, milk, or saliva) and seek care urgently; later splint and perform endodontic treatment as indicated.

What is the most commonly used laser type in soft-tissue dentistry, and one used for hard tissue?

Diode and Nd:YAG lasers for soft tissue; Erbium lasers (Er:YAG / Er,Cr:YSGG) for hard tissue (caries removal, cavity prep) due to water absorption.

What is regenerative endodontics?

Biologically based procedures to replace damaged pulp-dentin tissue, typically via revascularization in immature necrotic teeth using disinfection, blood clot/scaffold, and a coronal seal to promote continued root development.