List all 6 classes of G.V. Black's Classification of Dental Caries and Cavity Preparations (Class I through Class VI).

Class I: Pits and fissures on occlusal surfaces of premolars/molars, buccal/lingual pits of molars, and lingual pits of maxillary incisors. Class II: Proximal surfaces (mesial/distal) of POSTERIOR teeth (premolars and molars). Class III: Proximal surfaces of ANTERIOR teeth (incisors and canines) NOT involving the incisal angle. Class IV: Proximal surfaces of ANTERIOR teeth INVOLVING the incisal edge/angle. Class V: Cervical third of the facial or lingual surface of any tooth (smooth surface). Class VI: Incisal edges of anterior teeth or cusp tips of posterior teeth.

Describe the 4 histological zones of an Incipient Enamel Caries lesion (White Spot Lesion) from deepest to surface, and explain why it looks chalky white when dried.

From deepest (advancing front) to outer surface: 1. Translucent Zone (earliest advancing front, ~1% pore volume); 2. Dark Zone (2–4% pore volume); 3. Body of the Lesion (largest zone of demineralization, 5–25% pore volume); 4. Intact Surface Zone (~1% pore volume, maintained by salivary remineralization). Sound enamel has a Refractive Index (RI) of `1.62`; water has `RI = 1.33` and air has `RI = 1.00`. When a porous white-spot lesion is air-dried, air replaces water in the pores (`1.62 vs 1.00`), scattering light and appearing opaque chalky white (reversible without drilling!).

Compare the FDI Two-Digit System and the Palmer Notation System with the Universal System for permanent and primary teeth.

FDI System: First digit denotes the quadrant (1=Maxillary Right, 2=Maxillary Left, 3=Mandibular Left, 4=Mandibular Right for permanent; 5, 6, 7, 8 for primary) and second digit denotes tooth position from the midline (`1` central incisor to `8` third molar; e.g., #3 = FDI `16`, #19 = FDI `36`). Palmer Notation uses a quadrant bracket (`┘ └ ┐ ┌`) with numbers `1–8` (permanent) or letters `A–E` (primary) from the midline.

How do Primary (Flush Terminal Plane, Mesial Step, Distal Step) molar relationships predict Permanent Angle's occlusion?

Evaluated at the distal surfaces of the primary second molars (A/T and J/K): Mesial Step (mandibular distal surface is mesial to maxillary) typically transitions to Permanent Class I (or Class III if severe). Flush Terminal Plane (distal surfaces in the same vertical plane) transitions to Class I via early/late mesial shift into leeway/primate spaces (or end-to-end Class II). Distal Step almost always results in Permanent Class II malocclusion.

What are Primate Spaces and Leeway Space in the mixed dentition?

Primate Spaces: Natural developmental diastemas in the primary dentition located MESIAL to the maxillary primary canines (between B–C and H–I) and DISTAL to the mandibular primary canines (between N–M and Q–R). Leeway Space of Nance: The difference between the combined mesiodistal width of the primary canine + first and second primary molars (`C+D+E`) versus their permanent successors (permanent canine + first and second premolars)—larger in the mandible (~1.7 mm per side) than maxilla (~0.9 mm per side), allowing the late mesial shift of permanent first molars into Class I.

Define Angle's Classification of Malocclusion (Class I, Class II Division 1, Class II Division 2, and Class III) using the permanent first molars.

Class I (Neutrocclusion): The Mesiobuccal (MB) cusp of the Maxillary First Molar occludes in the Mesiobuccal groove of the Mandibular First Molar (normal molar relationship, with crowding/rotations). Class II (Distocclusion / Retrognathic): Mandibular molar is distal to Class I (Maxillary MB cusp is mesial to mandibular MB groove)—Div 1 has proclined maxillary incisors (large overjet); Div 2 has retroclined central incisors and labially flared laterals (deep overbite). Class III (Mesiocclusion / Prognathic): Mandibular molar is mesial to Class I (Maxillary MB cusp is distal to mandibular MB groove; anterior crossbite/underbite).

Compare the occlusal groove patterns (`Y`, `H`, `+`) and cusp counts of the Mandibular First Premolar (#21/#28) and Mandibular Second Premolar (#20/#29).

Mandibular First Premolar (#21/#28): Has a large buccal cusp and a tiny, non-functional lingual cusp (~2/3 height of buccal), a prominent transverse ridge, a Mesiolingual Developmental Groove, and an occlusal surface tilted 45 degrees lingually. Mandibular Second Premolar (#20/#29): Most commonly has 3 cusps (1 Buccal, 1 Mesiolingual, 1 Distolingual; ML > DL) forming a `Y` occlusal groove pattern (or 2 cusps forming a `U` or `H` groove pattern) and NO mesiolingual groove.

Compare the roles of *Streptococcus mutans*, *Lactobacillus* species, and *Actinomyces viscosus* in dental caries pathogenesis.

*Streptococcus mutans*: Primary initiator of coronal smooth-surface and pit-and-fissure enamel caries; both acidogenic (produces lactic acid via glycolysis) and aciduric (thrives at low pH), and uses glucosyltransferase (GTF) enzymes to synthesize insoluble extracellular mutans/glucans from sucrose for biofilm adhesion. *Lactobacillus* spp.: Secondary invaders dominating deep dentinal progression (cavitation). *Actinomyces naeslundii / viscosus*: Predominant in root-surface (cemental) caries in older patients with gingival recession.

Describe the histological zones of Dentinal Caries from the pulp outward toward the DEJ, and distinguish Affected vs Infected Dentin.

From pulp outward: 1. Normal Dentin; 2. Subtransparent / Sclerotic Dentin (mineral crystals deposited inside tubules to block bacterial advance); 3. Transparent Dentin (demineralized intertubular dentin with intact collagen cross-links and NO bacteria—this is 'Affected Dentin' which is leathery/firm and SHOULD BE PRESERVED for remineralization); 4. Turbid / Bacterial Invasion Zone and 5. Necrotic/Decomposed Zone ('Infected Dentin'—denatured collagen teaming with bacteria, soft/wet, MUST be excavated peripherally).

Compare Reversible Pulpitis, Symptomatic Irreversible Pulpitis, Pulp Necrosis, and Symptomatic Apical Periodontitis on endodontic diagnostic testing.

Reversible Pulpitis: Sharp, brief pain triggered by cold/sweet that resolves within seconds after removing the stimulus; no spontaneous pain, normal percussion (treat with caries removal/restoration). Symptomatic Irreversible Pulpitis: Sharp/throbbing pain to cold/heat that LINGERS (>30 seconds) after stimulus removal, spontaneous pain waking the patient at night, or pain relieved by cold in late stages (requires RCT or extraction). Pulp Necrosis: Non-responsive (negative) to cold and Electric Pulp Test (EPT). Symptomatic Apical Periodontitis: Painful response to vertical Percussion and biting (inflammation has reached the PDL at the apex).

What are the three mechanisms of action of Fluoride, the optimal community water fluoridation concentration, and acute fluoride toxicity thresholds?

Mechanisms: 1. Replaces hydroxyl (`OH-`) ions in hydroxyapatite to form Fluorapatite (`Ca10(PO4)6F2`), lowering critical pH from 5.5 to 4.5; 2. Enhances remineralization of incipient enamel lesions with calcium and phosphate; 3. Inhibits bacterial enolase enzyme in glycolysis at high topical concentrations. Optimal US water fluoridation: `0.7 ppm` (mg/L). Acute Toxicity: Probably Toxic Dose (PTD) is `5 mg/kg` (give oral calcium/milk to bind fluoride in gut); Certainly Lethal Dose (CLD) is `32–64 mg/kg`.

In Dental Amalgam, what are the roles of Silver, Tin, Copper, and Mercury, and why did High-Copper Amalgam (>12% Cu) eliminate the Gamma-2 (`Sn7-8Hg`) phase?

Silver (`Ag`): Increases strength and expansion; Tin (`Sn`): Increases setting time and contraction; Copper (`Cu`): Increases strength and hardness and eliminates the Gamma-2 phase; Zinc (`Zn`): Oxygen scavenger during manufacturing (causes delayed expansion if contaminated with moisture during condensation in Zn-containing low-copper amalgams). In low-copper amalgams, `Ag3Sn` (gamma) + `Hg` formed `Ag2Hg3` (gamma-1) + `Sn7-8Hg` (gamma-2, the weakest and most corrosion/creep-prone phase). High-Copper amalgams react `Cu` with `Sn` to form `Cu6Sn5` (eta phase), eliminating gamma-2.

Compare Mineral Trioxide Aggregate (MTA) / Biodentine and Calcium Hydroxide (`Ca(OH)2`) for Direct Pulp Capping and Vital Pulp Therapy.

Both have an alkaline pH (~12–12.5) that is bactericidal and stimulates alkaline phosphatase and reparative dentin bridge formation. However, Calcium Hydroxide (`Ca(OH)2`, e.g., Dycal) dissolves over time ('tunnel defects' in the dentin bridge) and does not seal well against microleakage. Hydraulic Calcium Silicate cements (MTA and Biodentine) are hydrophilic, set in the presence of moisture/blood, provide a superior hermetic bacterial seal, do not resorb, and induce thicker, more homogeneous tubular dentin bridges.

How does 38% Silver Diamine Fluoride (SDF) arrest carious lesions, and what are its main indication and side effect?

38% SDF (`Ag(NH3)2F`, ~44,800 ppm fluoride + 25% silver at pH 10) combines the bactericidal and collagenase/MMP-inhibiting effects of silver ions (`Ag+`) with the remineralizing action of high-concentration fluoride (`F-`), forming a hard, arrested squamous layer of silver phosphate and calcium fluoride (`CaF2`). It is non-invasive for arresting cavitated dentin lesions in young children, special-needs, or frail elderly patients, with the primary aesthetic drawback that it permanently stains carious/demineralized tooth structure jet black (sound enamel does not stain).

Differentiate between Attrition, Abrasion, Abfraction, and Erosion of tooth structure.

Attrition: Physiological or pathological tooth-to-tooth wear on incisal/occlusal surfaces (e.g., bruxism producing matching wear facets). Abrasion: Pathological mechanical wear from exogenous foreign objects (e.g., aggressive horizontal toothbrushing causing V-shaped cervical notches on premolars/canines). Abfraction: Wedge-shaped cervical microfractures at the CEJ caused by eccentric occlusal flexural biomechanical forces. Erosion: Chemical dissolution of tooth structure by NON-BACTERIAL acids—either extrinsic (citrus, soda, wine on facial surfaces) or intrinsic (GERD/bulimia gastric acid causing perimylolysis on palatal surfaces of maxillary teeth and raised amalgam 'islands').

What is the Polymerization Shrinkage C-Factor (Configuration Factor) in resin composite restorations, and which cavity class has the highest C-Factor?

The C-Factor is the ratio of BONDED composite surfaces to UNBONDED (free) surfaces (`C = Bonded / Unbonded`). Higher C-factor means less free surface area to flow and relieve polymerization shrinkage stress (~2%), increasing risk of marginal gap formation, microleakage, cuspal deflection, and postoperative sensitivity. Box-like Class I and Class V cavities have the highest C-Factor (`5 bonded / 1 unbonded = 5.0`), whereas Class IV has the lowest (`1/5 = 0.2`); incremental oblique layering (<2 mm increments) reduces effective C-factor stress.

How many roots and root canals are typically found in Maxillary First Molars (#3/#14), Maxillary Incisors/Canines, and Mandibular Incisors?

Maxillary First Molar (#3/#14): 3 roots (Mesiobuccal, Distobuccal, Palatal—Palatal is longest; MB is broadest buccolingually) and typically 4 canals because the Mesiobuccal root contains an `MB2` canal in >70–90% of cases (located mesial and lingual to `MB1`). Maxillary Incisors & Canines: 1 root, 1 canal (#6/#11 canine has the longest root in the mouth). Mandibular Incisors: 1 root, but a second lingual canal is present in ~25–40% of cases.

Trace the borders of Posselt's Envelope of Motion in the sagittal plane (CR, MI/CO, Maximum Opening, and Edge-to-Edge/Protrusion).

1. Centric Relation (CR): Most superior-anterior musculoskeletal position of the condyles in the glenoid fossae with the articular discs properly interposed (independent of tooth contact). 2. From CR, the mandible slides 0.5–1.5 mm anteriorly and superiorly into Maximum Intercuspation (MI / Centric Occlusion). 3. Opening from CR has two phases: pure hinge rotation for the first 20–25 mm, followed by translation of the condyle-disc complex down the articular eminence to Maximum Opening (~40–50 mm). 4. Superior border goes from CR -> MI -> incisal edge-to-edge -> Maximum Protrusion.

What are the distinguishing anatomical features and root morphology of the Maxillary First Premolar (#5 / #12)?

1. The ONLY premolar that typically has TWO roots (1 Buccal, 1 Palatal/Lingual) and two pulp canals; 2. Pronounced mesial crown/root concavity (fluting) making periodontal scaling difficult and predisposing to root perforation; 3. Prominent Mesial Marginal Developmental Groove; 4. Unique among premolars: its mesial cusp slope is LONGER than its distal cusp slope on the buccal cusp.

How does the Universal Numbering System number the 32 permanent teeth and the 20 primary (deciduous) teeth?

Permanent teeth (1–32): Starts at the maxillary right third molar (#1), proceeds clockwise across the maxillary arch to the maxillary left third molar (#16), drops to the mandibular left third molar (#17), and continues to the mandibular right third molar (#32). Primary teeth (A–T): Follows the same clockwise path starting at the maxillary right second primary molar (A) to (J), dropping to mandibular left (K) through mandibular right (T).

What are Bennett Movement (Immediate Side Shift), Bennett Angle, Curve of Spee, and Curve of Wilson?

Bennett Movement: The bodily lateral shift of the mandible toward the working side during lateral excursions. Bennett Angle: The angle formed in the horizontal plane between the sagittal plane and the pathway of the advancing non-working (mediotrusive) condyle as it moves forward and medially. Curve of Spee: Anteroposterior curvature of the occlusal plane (concave upward) from canine tip along buccal cusps of posterior teeth. Curve of Wilson: Mediolateral curvature in the frontal plane resulting from lingual inclination of mandibular molars and buccal inclination of maxillary molars.

Compare the mineral vs organic/water composition and embryological origin of Enamel, Dentin, Cementum, and Pulp.

Enamel: Ectodermal origin (ameloblasts from inner enamel epithelium); 96% inorganic hydroxyapatite (`Ca10(PO4)6(OH)2`), 4% water/organic (amelogenins)—hardest tissue in the body, acellular/avascular (cannot regenerate). Dentin: Ectomesenchymal/neural crest origin (odontoblasts); 70% inorganic, 20% organic (Type I collagen), 10% water. Cementum: Ectomesenchymal; 65% inorganic, 23% organic, 12% water (closest to bone). Pulp: Dental papilla mesenchyme; neurovascular connective tissue.

Compare Total-Etch (Etch-and-Rinse) and Self-Etch dental adhesive systems on Enamel versus Dentin.

Enamel bonding relies on 35–37% Phosphoric Acid etching for 15–30s to dissolve prism cores/peripheries and create microporosities for micromechanical resin tags (~20–30 MPa). Dentin bonding requires etching only briefly (10–15s) to remove the smear layer and expose the superficial Type I collagen fibril network without over-drying ('wet bonding' with HEMA hydrophilic primer prevents collagen collapse) to form the Hybrid Layer. Self-Etch primers use acidic monomers to simultaneously demineralize and infiltrate dentin without a separate rinse step (less postoperative sensitivity), while Selective Enamel Etch adds phosphoric acid ONLY to the enamel margins.

What are the 5 cusps (in order of size) and root structure of the Permanent Mandibular First Molar (#19 and #30)?

#19/#30 is the first permanent tooth to erupt, has the largest mesiodistal crown dimension of any tooth, and has 2 roots (Mesial with 2 canals MB/ML, Distal with 1–2 canals) and 5 cusps (3 Buccal, 2 Lingual). Cusp size from largest to smallest: Mesiobuccal (MB) > Mesiolingual (ML) > Distolingual (DL) > Distobuccal (DB) > Distal (D, smallest). Its lingual cusps are taller/pointed, and its occlusal developmental grooves form a 'Y' pattern with two buccal grooves (MB and DB).

Explain the Stephan Curve in cariology and compare the critical pH for Enamel demineralization, Fluorapatite, and Root Dentin/Cementum.

The Stephan Curve plots dental plaque pH over time after a fermentable carbohydrate rinse: pH drops rapidly within 2–5 minutes due to bacterial lactic acid production and takes 30–60 minutes to recover via salivary bicarbonate/phosphate buffering. Critical pH for Hydroxyapatite Enamel: `5.5` (demineralizes below 5.5). Critical pH for Fluorapatite: `4.5` (more acid-resistant). Critical pH for Root Dentin / Cementum: `6.2 to 6.7` (demineralizes much more easily at near-neutral pH!).

Define Height of Contour (Crest of Curvature) locations on the facial and lingual surfaces of all anterior and posterior teeth.

Facial (Labial/Buccal) Height of Contour: Located in the CERVICAL THIRD on ALL teeth (both anterior and posterior). Lingual Height of Contour: Located in the CERVICAL THIRD on Anterior teeth (on the cingulum), and in the MIDDLE THIRD on Posterior teeth (premolars and molars).

Which permanent teeth possess the Cusp of Carabelli, the Oblique Ridge, and the Mesial Marginal Developmental Groove?

Cusp of Carabelli: A non-functional 5th supplemental cusp found on the mesiolingual (ML) cusp of the Maxillary First Molar (#3 and #14, and primary tooth A/J). Oblique Ridge: Connects the Mesiolingual (ML) and Distobuccal (DB) cusps on Maxillary Molars. Mesial Marginal Developmental Groove: Crosses the mesial marginal ridge and extends onto the mesial root concavity of the Maxillary First Premolar (#5 and #12).

Differentiate between Primary, Secondary, and Tertiary (Reactionary vs Reparative) Dentin, and explain hydrodynamic sensitivity.

Primary Dentin: Formed before apical root completion (includes outermost 150-um Mantle Dentin and Circumpulpal Dentin). Secondary Dentin: Formed slowly throughout life after root completion, gradually narrowing the pulp chamber. Tertiary Dentin: Deposited rapidly in response to caries/trauma—Reactionary if secreted by surviving native odontoblasts, or Reparative (osteodentin) if odontoblasts die and undifferentiated pulp stem cells differentiate into odontoblast-like cells. Brannstrom's Hydrodynamic Theory: Fluid movement inside dentinal tubules stimulates A-delta mechanoreceptors at the pulp-dentin border.

Compare Glass Ionomer Cement (GIC), Resin-Modified Glass Ionomer (RMGIC), and Composite Resin.

Conventional GIC sets via an acid-base reaction between fluoroaluminosilicate glass powder and polyacrylic acid liquid: it chemically chelates directly to calcium in tooth structure without bonding agents, has a thermal expansion coefficient matching dentin, and releases/recharges Fluoride continuously (ideal for high-caries-risk Class V root lesions and ATR), but has low fracture toughness and poorer aesthetics. RMGIC adds light-curable HEMA resin for improved strength and command set while retaining fluoride release. Composite Resin has superior aesthetics and wear resistance via silane-coupled filler particles in Bis-GMA/UDMA matrix.

What is the typical eruption sequence and age timeline for the 20 primary (deciduous) teeth?

Order of eruption: Central Incisors (6–10 mos, mandibular first) -> Lateral Incisors (9–13 mos, maxillary first) -> First Primary Molars (13–16 mos) -> Canines (16–22 mos) -> Second Primary Molars (23–33 mos). Mnemonic: `C - L - 1st Molar - Canine - 2nd Molar` (all 20 primary teeth usually erupted by age 2.5–3 years).

What is the typical eruption sequence and age timeline for permanent mandibular and maxillary teeth?

Permanent eruption begins at age 6 with the First Molars ('6-year molars', #3, #14, #19, #30). Mandibular sequence: First Molar (6–7 yr) -> Central Incisor (6–7) -> Lateral Incisor (7–8) -> Canine (9–10) -> First Premolar (10–12) -> Second Premolar (11–12) -> Second Molar (11–13) -> Third Molar (17–21). In the Maxillary arch, the Canine erupts AFTER the First and Second Premolars (11–12 yr).

Compare Working (Laterotrusive), Non-Working (Mediotrusive / Balancing), and Protrusive mandibular movements and the cusps involved.

Supporting (Holding/Centric) Cusps are `BULL`: Buccal of Mandibular (`B` of `L`) and Lingual of Maxillary (`L` of `U`). Non-Supporting (Guiding/Shearing) Cusps are `LUBL` (Lingual of Lower, Buccal of Upper). During a Working (Laterotrusive) movement to the right, the right condyle rotates (Working side) while the left condyle translates downward, forward, and medially (Non-Working / Balancing side). Canine Guidance discludes all posterior teeth during lateral excursion via the canines; Group Function shares lateral load across working-side buccal cusps.

Dental Anatomy (Universal Numbering, Tooth Morphology, Eruption & Occlusion) & Cariology

High-yield INBDE and DAT dental anatomy and cariology: Universal, Palmer, and FDI numbering systems, primary/permanent eruption sequences, enamel/dentin/pulp histology, crown/root morphology landmarks, Angle's classification of malocclusion, Posselt's envelope, Bennett movement, Stephan curve, G.V. Black cavity classifications, fluoride/SDF, and restorative materials.

Level: basic
Languages: en → en
Cards: 32
Markdown: Dental Anatomy (Universal Numbering, Tooth Morphology, Eruption & Occlusion) & Cariology (.md)

Flashcards (32)

#	Front (Term / Question)	Back (Definition / Answer)
1	List all 6 classes of G.V. Black's Classification of Dental Caries and Cavity Preparations (Class I through Class VI).	Class I: Pits and fissures on occlusal surfaces of premolars/molars, buccal/lingual pits of molars, and lingual pits of maxillary incisors. Class II: Proximal surfaces (mesial/distal) of POSTERIOR teeth (premolars and molars). Class III: Proximal surfaces of ANTERIOR teeth (incisors and canines) NOT involving the incisal angle. Class IV: Proximal surfaces of ANTERIOR teeth INVOLVING the incisal edge/angle. Class V: Cervical third of the facial or lingual surface of any tooth (smooth surface). Class VI: Incisal edges of anterior teeth or cusp tips of posterior teeth.
2	Describe the 4 histological zones of an Incipient Enamel Caries lesion (White Spot Lesion) from deepest to surface, and explain why it looks chalky white when dried.	From deepest (advancing front) to outer surface: 1. Translucent Zone (earliest advancing front, ~1% pore volume); 2. Dark Zone (2–4% pore volume); 3. Body of the Lesion (largest zone of demineralization, 5–25% pore volume); 4. Intact Surface Zone (~1% pore volume, maintained by salivary remineralization). Sound enamel has a Refractive Index (RI) of `1.62`; water has `RI = 1.33` and air has `RI = 1.00`. When a porous white-spot lesion is air-dried, air replaces water in the pores (`1.62 vs 1.00`), scattering light and appearing opaque chalky white (reversible without drilling!).
3	Compare the FDI Two-Digit System and the Palmer Notation System with the Universal System for permanent and primary teeth.	FDI System: First digit denotes the quadrant (1=Maxillary Right, 2=Maxillary Left, 3=Mandibular Left, 4=Mandibular Right for permanent; 5, 6, 7, 8 for primary) and second digit denotes tooth position from the midline (`1` central incisor to `8` third molar; e.g., #3 = FDI `16`, #19 = FDI `36`). Palmer Notation uses a quadrant bracket (`┘ └ ┐ ┌`) with numbers `1–8` (permanent) or letters `A–E` (primary) from the midline.
4	How do Primary (Flush Terminal Plane, Mesial Step, Distal Step) molar relationships predict Permanent Angle's occlusion?	Evaluated at the distal surfaces of the primary second molars (A/T and J/K): Mesial Step (mandibular distal surface is mesial to maxillary) typically transitions to Permanent Class I (or Class III if severe). Flush Terminal Plane (distal surfaces in the same vertical plane) transitions to Class I via early/late mesial shift into leeway/primate spaces (or end-to-end Class II). Distal Step almost always results in Permanent Class II malocclusion.
5	What are Primate Spaces and Leeway Space in the mixed dentition?	Primate Spaces: Natural developmental diastemas in the primary dentition located MESIAL to the maxillary primary canines (between B–C and H–I) and DISTAL to the mandibular primary canines (between N–M and Q–R). Leeway Space of Nance: The difference between the combined mesiodistal width of the primary canine + first and second primary molars (`C+D+E`) versus their permanent successors (permanent canine + first and second premolars)—larger in the mandible (~1.7 mm per side) than maxilla (~0.9 mm per side), allowing the late mesial shift of permanent first molars into Class I.
6	Define Angle's Classification of Malocclusion (Class I, Class II Division 1, Class II Division 2, and Class III) using the permanent first molars.	Class I (Neutrocclusion): The Mesiobuccal (MB) cusp of the Maxillary First Molar occludes in the Mesiobuccal groove of the Mandibular First Molar (normal molar relationship, with crowding/rotations). Class II (Distocclusion / Retrognathic): Mandibular molar is distal to Class I (Maxillary MB cusp is mesial to mandibular MB groove)—Div 1 has proclined maxillary incisors (large overjet); Div 2 has retroclined central incisors and labially flared laterals (deep overbite). Class III (Mesiocclusion / Prognathic): Mandibular molar is mesial to Class I (Maxillary MB cusp is distal to mandibular MB groove; anterior crossbite/underbite).
7	Compare the occlusal groove patterns (`Y`, `H`, `+`) and cusp counts of the Mandibular First Premolar (#21/#28) and Mandibular Second Premolar (#20/#29).	Mandibular First Premolar (#21/#28): Has a large buccal cusp and a tiny, non-functional lingual cusp (~2/3 height of buccal), a prominent transverse ridge, a Mesiolingual Developmental Groove, and an occlusal surface tilted 45 degrees lingually. Mandibular Second Premolar (#20/#29): Most commonly has 3 cusps (1 Buccal, 1 Mesiolingual, 1 Distolingual; ML > DL) forming a `Y` occlusal groove pattern (or 2 cusps forming a `U` or `H` groove pattern) and NO mesiolingual groove.
8	Compare the roles of Streptococcus mutans, Lactobacillus species, and Actinomyces viscosus in dental caries pathogenesis.	Streptococcus mutans: Primary initiator of coronal smooth-surface and pit-and-fissure enamel caries; both acidogenic (produces lactic acid via glycolysis) and aciduric (thrives at low pH), and uses glucosyltransferase (GTF) enzymes to synthesize insoluble extracellular mutans/glucans from sucrose for biofilm adhesion. Lactobacillus spp.: Secondary invaders dominating deep dentinal progression (cavitation). Actinomyces naeslundii / viscosus: Predominant in root-surface (cemental) caries in older patients with gingival recession.
9	Describe the histological zones of Dentinal Caries from the pulp outward toward the DEJ, and distinguish Affected vs Infected Dentin.	From pulp outward: 1. Normal Dentin; 2. Subtransparent / Sclerotic Dentin (mineral crystals deposited inside tubules to block bacterial advance); 3. Transparent Dentin (demineralized intertubular dentin with intact collagen cross-links and NO bacteria—this is 'Affected Dentin' which is leathery/firm and SHOULD BE PRESERVED for remineralization); 4. Turbid / Bacterial Invasion Zone and 5. Necrotic/Decomposed Zone ('Infected Dentin'—denatured collagen teaming with bacteria, soft/wet, MUST be excavated peripherally).
10	Compare Reversible Pulpitis, Symptomatic Irreversible Pulpitis, Pulp Necrosis, and Symptomatic Apical Periodontitis on endodontic diagnostic testing.	Reversible Pulpitis: Sharp, brief pain triggered by cold/sweet that resolves within seconds after removing the stimulus; no spontaneous pain, normal percussion (treat with caries removal/restoration). Symptomatic Irreversible Pulpitis: Sharp/throbbing pain to cold/heat that LINGERS (>30 seconds) after stimulus removal, spontaneous pain waking the patient at night, or pain relieved by cold in late stages (requires RCT or extraction). Pulp Necrosis: Non-responsive (negative) to cold and Electric Pulp Test (EPT). Symptomatic Apical Periodontitis: Painful response to vertical Percussion and biting (inflammation has reached the PDL at the apex).
11	What are the three mechanisms of action of Fluoride, the optimal community water fluoridation concentration, and acute fluoride toxicity thresholds?	Mechanisms: 1. Replaces hydroxyl (`OH-`) ions in hydroxyapatite to form Fluorapatite (`Ca10(PO4)6F2`), lowering critical pH from 5.5 to 4.5; 2. Enhances remineralization of incipient enamel lesions with calcium and phosphate; 3. Inhibits bacterial enolase enzyme in glycolysis at high topical concentrations. Optimal US water fluoridation: `0.7 ppm` (mg/L). Acute Toxicity: Probably Toxic Dose (PTD) is `5 mg/kg` (give oral calcium/milk to bind fluoride in gut); Certainly Lethal Dose (CLD) is `32–64 mg/kg`.
12	In Dental Amalgam, what are the roles of Silver, Tin, Copper, and Mercury, and why did High-Copper Amalgam (>12% Cu) eliminate the Gamma-2 (`Sn7-8Hg`) phase?	Silver (`Ag`): Increases strength and expansion; Tin (`Sn`): Increases setting time and contraction; Copper (`Cu`): Increases strength and hardness and eliminates the Gamma-2 phase; Zinc (`Zn`): Oxygen scavenger during manufacturing (causes delayed expansion if contaminated with moisture during condensation in Zn-containing low-copper amalgams). In low-copper amalgams, `Ag3Sn` (gamma) + `Hg` formed `Ag2Hg3` (gamma-1) + `Sn7-8Hg` (gamma-2, the weakest and most corrosion/creep-prone phase). High-Copper amalgams react `Cu` with `Sn` to form `Cu6Sn5` (eta phase), eliminating gamma-2.
13	Compare Mineral Trioxide Aggregate (MTA) / Biodentine and Calcium Hydroxide (`Ca(OH)2`) for Direct Pulp Capping and Vital Pulp Therapy.	Both have an alkaline pH (~12–12.5) that is bactericidal and stimulates alkaline phosphatase and reparative dentin bridge formation. However, Calcium Hydroxide (`Ca(OH)2`, e.g., Dycal) dissolves over time ('tunnel defects' in the dentin bridge) and does not seal well against microleakage. Hydraulic Calcium Silicate cements (MTA and Biodentine) are hydrophilic, set in the presence of moisture/blood, provide a superior hermetic bacterial seal, do not resorb, and induce thicker, more homogeneous tubular dentin bridges.
14	How does 38% Silver Diamine Fluoride (SDF) arrest carious lesions, and what are its main indication and side effect?	38% SDF (`Ag(NH3)2F`, ~44,800 ppm fluoride + 25% silver at pH 10) combines the bactericidal and collagenase/MMP-inhibiting effects of silver ions (`Ag+`) with the remineralizing action of high-concentration fluoride (`F-`), forming a hard, arrested squamous layer of silver phosphate and calcium fluoride (`CaF2`). It is non-invasive for arresting cavitated dentin lesions in young children, special-needs, or frail elderly patients, with the primary aesthetic drawback that it permanently stains carious/demineralized tooth structure jet black (sound enamel does not stain).
15	Differentiate between Attrition, Abrasion, Abfraction, and Erosion of tooth structure.	Attrition: Physiological or pathological tooth-to-tooth wear on incisal/occlusal surfaces (e.g., bruxism producing matching wear facets). Abrasion: Pathological mechanical wear from exogenous foreign objects (e.g., aggressive horizontal toothbrushing causing V-shaped cervical notches on premolars/canines). Abfraction: Wedge-shaped cervical microfractures at the CEJ caused by eccentric occlusal flexural biomechanical forces. Erosion: Chemical dissolution of tooth structure by NON-BACTERIAL acids—either extrinsic (citrus, soda, wine on facial surfaces) or intrinsic (GERD/bulimia gastric acid causing perimylolysis on palatal surfaces of maxillary teeth and raised amalgam 'islands').
16	What is the Polymerization Shrinkage C-Factor (Configuration Factor) in resin composite restorations, and which cavity class has the highest C-Factor?	The C-Factor is the ratio of BONDED composite surfaces to UNBONDED (free) surfaces (`C = Bonded / Unbonded`). Higher C-factor means less free surface area to flow and relieve polymerization shrinkage stress (~2%), increasing risk of marginal gap formation, microleakage, cuspal deflection, and postoperative sensitivity. Box-like Class I and Class V cavities have the highest C-Factor (`5 bonded / 1 unbonded = 5.0`), whereas Class IV has the lowest (`1/5 = 0.2`); incremental oblique layering (<2 mm increments) reduces effective C-factor stress.
17	How many roots and root canals are typically found in Maxillary First Molars (#3/#14), Maxillary Incisors/Canines, and Mandibular Incisors?	Maxillary First Molar (#3/#14): 3 roots (Mesiobuccal, Distobuccal, Palatal—Palatal is longest; MB is broadest buccolingually) and typically 4 canals because the Mesiobuccal root contains an `MB2` canal in >70–90% of cases (located mesial and lingual to `MB1`). Maxillary Incisors & Canines: 1 root, 1 canal (#6/#11 canine has the longest root in the mouth). Mandibular Incisors: 1 root, but a second lingual canal is present in ~25–40% of cases.
18	Trace the borders of Posselt's Envelope of Motion in the sagittal plane (CR, MI/CO, Maximum Opening, and Edge-to-Edge/Protrusion).	1. Centric Relation (CR): Most superior-anterior musculoskeletal position of the condyles in the glenoid fossae with the articular discs properly interposed (independent of tooth contact). 2. From CR, the mandible slides 0.5–1.5 mm anteriorly and superiorly into Maximum Intercuspation (MI / Centric Occlusion). 3. Opening from CR has two phases: pure hinge rotation for the first 20–25 mm, followed by translation of the condyle-disc complex down the articular eminence to Maximum Opening (~40–50 mm). 4. Superior border goes from CR -> MI -> incisal edge-to-edge -> Maximum Protrusion.
19	What are the distinguishing anatomical features and root morphology of the Maxillary First Premolar (#5 / #12)?	1. The ONLY premolar that typically has TWO roots (1 Buccal, 1 Palatal/Lingual) and two pulp canals; 2. Pronounced mesial crown/root concavity (fluting) making periodontal scaling difficult and predisposing to root perforation; 3. Prominent Mesial Marginal Developmental Groove; 4. Unique among premolars: its mesial cusp slope is LONGER than its distal cusp slope on the buccal cusp.
20	How does the Universal Numbering System number the 32 permanent teeth and the 20 primary (deciduous) teeth?	Permanent teeth (1–32): Starts at the maxillary right third molar (#1), proceeds clockwise across the maxillary arch to the maxillary left third molar (#16), drops to the mandibular left third molar (#17), and continues to the mandibular right third molar (#32). Primary teeth (A–T): Follows the same clockwise path starting at the maxillary right second primary molar (A) to (J), dropping to mandibular left (K) through mandibular right (T).
21	What are Bennett Movement (Immediate Side Shift), Bennett Angle, Curve of Spee, and Curve of Wilson?	Bennett Movement: The bodily lateral shift of the mandible toward the working side during lateral excursions. Bennett Angle: The angle formed in the horizontal plane between the sagittal plane and the pathway of the advancing non-working (mediotrusive) condyle as it moves forward and medially. Curve of Spee: Anteroposterior curvature of the occlusal plane (concave upward) from canine tip along buccal cusps of posterior teeth. Curve of Wilson: Mediolateral curvature in the frontal plane resulting from lingual inclination of mandibular molars and buccal inclination of maxillary molars.
22	Compare the mineral vs organic/water composition and embryological origin of Enamel, Dentin, Cementum, and Pulp.	Enamel: Ectodermal origin (ameloblasts from inner enamel epithelium); 96% inorganic hydroxyapatite (`Ca10(PO4)6(OH)2`), 4% water/organic (amelogenins)—hardest tissue in the body, acellular/avascular (cannot regenerate). Dentin: Ectomesenchymal/neural crest origin (odontoblasts); 70% inorganic, 20% organic (Type I collagen), 10% water. Cementum: Ectomesenchymal; 65% inorganic, 23% organic, 12% water (closest to bone). Pulp: Dental papilla mesenchyme; neurovascular connective tissue.
23	Compare Total-Etch (Etch-and-Rinse) and Self-Etch dental adhesive systems on Enamel versus Dentin.	Enamel bonding relies on 35–37% Phosphoric Acid etching for 15–30s to dissolve prism cores/peripheries and create microporosities for micromechanical resin tags (~20–30 MPa). Dentin bonding requires etching only briefly (10–15s) to remove the smear layer and expose the superficial Type I collagen fibril network without over-drying ('wet bonding' with HEMA hydrophilic primer prevents collagen collapse) to form the Hybrid Layer. Self-Etch primers use acidic monomers to simultaneously demineralize and infiltrate dentin without a separate rinse step (less postoperative sensitivity), while Selective Enamel Etch adds phosphoric acid ONLY to the enamel margins.
24	What are the 5 cusps (in order of size) and root structure of the Permanent Mandibular First Molar (#19 and #30)?	#19/#30 is the first permanent tooth to erupt, has the largest mesiodistal crown dimension of any tooth, and has 2 roots (Mesial with 2 canals MB/ML, Distal with 1–2 canals) and 5 cusps (3 Buccal, 2 Lingual). Cusp size from largest to smallest: Mesiobuccal (MB) > Mesiolingual (ML) > Distolingual (DL) > Distobuccal (DB) > Distal (D, smallest). Its lingual cusps are taller/pointed, and its occlusal developmental grooves form a 'Y' pattern with two buccal grooves (MB and DB).
25	Explain the Stephan Curve in cariology and compare the critical pH for Enamel demineralization, Fluorapatite, and Root Dentin/Cementum.	The Stephan Curve plots dental plaque pH over time after a fermentable carbohydrate rinse: pH drops rapidly within 2–5 minutes due to bacterial lactic acid production and takes 30–60 minutes to recover via salivary bicarbonate/phosphate buffering. Critical pH for Hydroxyapatite Enamel: `5.5` (demineralizes below 5.5). Critical pH for Fluorapatite: `4.5` (more acid-resistant). Critical pH for Root Dentin / Cementum: `6.2 to 6.7` (demineralizes much more easily at near-neutral pH!).
26	Define Height of Contour (Crest of Curvature) locations on the facial and lingual surfaces of all anterior and posterior teeth.	Facial (Labial/Buccal) Height of Contour: Located in the CERVICAL THIRD on ALL teeth (both anterior and posterior). Lingual Height of Contour: Located in the CERVICAL THIRD on Anterior teeth (on the cingulum), and in the MIDDLE THIRD on Posterior teeth (premolars and molars).
27	Which permanent teeth possess the Cusp of Carabelli, the Oblique Ridge, and the Mesial Marginal Developmental Groove?	Cusp of Carabelli: A non-functional 5th supplemental cusp found on the mesiolingual (ML) cusp of the Maxillary First Molar (#3 and #14, and primary tooth A/J). Oblique Ridge: Connects the Mesiolingual (ML) and Distobuccal (DB) cusps on Maxillary Molars. Mesial Marginal Developmental Groove: Crosses the mesial marginal ridge and extends onto the mesial root concavity of the Maxillary First Premolar (#5 and #12).
28	Differentiate between Primary, Secondary, and Tertiary (Reactionary vs Reparative) Dentin, and explain hydrodynamic sensitivity.	Primary Dentin: Formed before apical root completion (includes outermost 150-um Mantle Dentin and Circumpulpal Dentin). Secondary Dentin: Formed slowly throughout life after root completion, gradually narrowing the pulp chamber. Tertiary Dentin: Deposited rapidly in response to caries/trauma—Reactionary if secreted by surviving native odontoblasts, or Reparative (osteodentin) if odontoblasts die and undifferentiated pulp stem cells differentiate into odontoblast-like cells. Brannstrom's Hydrodynamic Theory: Fluid movement inside dentinal tubules stimulates A-delta mechanoreceptors at the pulp-dentin border.
29	Compare Glass Ionomer Cement (GIC), Resin-Modified Glass Ionomer (RMGIC), and Composite Resin.	Conventional GIC sets via an acid-base reaction between fluoroaluminosilicate glass powder and polyacrylic acid liquid: it chemically chelates directly to calcium in tooth structure without bonding agents, has a thermal expansion coefficient matching dentin, and releases/recharges Fluoride continuously (ideal for high-caries-risk Class V root lesions and ATR), but has low fracture toughness and poorer aesthetics. RMGIC adds light-curable HEMA resin for improved strength and command set while retaining fluoride release. Composite Resin has superior aesthetics and wear resistance via silane-coupled filler particles in Bis-GMA/UDMA matrix.
30	What is the typical eruption sequence and age timeline for the 20 primary (deciduous) teeth?	Order of eruption: Central Incisors (6–10 mos, mandibular first) -> Lateral Incisors (9–13 mos, maxillary first) -> First Primary Molars (13–16 mos) -> Canines (16–22 mos) -> Second Primary Molars (23–33 mos). Mnemonic: `C - L - 1st Molar - Canine - 2nd Molar` (all 20 primary teeth usually erupted by age 2.5–3 years).
31	What is the typical eruption sequence and age timeline for permanent mandibular and maxillary teeth?	Permanent eruption begins at age 6 with the First Molars ('6-year molars', #3, #14, #19, #30). Mandibular sequence: First Molar (6–7 yr) -> Central Incisor (6–7) -> Lateral Incisor (7–8) -> Canine (9–10) -> First Premolar (10–12) -> Second Premolar (11–12) -> Second Molar (11–13) -> Third Molar (17–21). In the Maxillary arch, the Canine erupts AFTER the First and Second Premolars (11–12 yr).
32	Compare Working (Laterotrusive), Non-Working (Mediotrusive / Balancing), and Protrusive mandibular movements and the cusps involved.	Supporting (Holding/Centric) Cusps are `BULL`: Buccal of Mandibular (`B` of `L`) and Lingual of Maxillary (`L` of `U`). Non-Supporting (Guiding/Shearing) Cusps are `LUBL` (Lingual of Lower, Buccal of Upper). During a Working (Laterotrusive) movement to the right, the right condyle rotates (Working side) while the left condyle translates downward, forward, and medially (Non-Working / Balancing side). Canine Guidance discludes all posterior teeth during lateral excursion via the canines; Group Function shares lateral load across working-side buccal cusps.