Divisions

• Vestibule: Space between lips/cheeks and teeth
• Oral cavity proper: Area behind teeth

Boundaries

• Anterior: Lips
• Posterior: Oropharynx
• Superior: Hard/soft palate
• Inferior: Tongue/floor of mouth
• Lateral: Cheeks

Crown Components

• Cusp: Elevated projection (molars have 4-5)
• Ridge: Linear elevation (marginal, triangular)
• Fossa: Depression (central, triangular)
• Groove: Shallow line (developmental, supplemental)
• Pit: Point depression (occlusal, lingual)

Root apex: Terminal end of root

Pulp chamber: Coronal portion of pulp cavity

Anterior Teeth

• Labial: Lip side (facial surface)
• Lingual: Tongue side
• Mesial: Toward midline
• Distal: Away from midline
• Incisal: Biting edge

Posterior Teeth

• Buccal: Cheek side (facial surface)
• Lingual: Tongue side
• Occlusal: Chewing surface
• Mesial/Distal: As above
• Proximal: Contact surfaces between teeth

Universal System

Permanent: 1-32 (upper right 3rd molar to lower right 3rd molar)

Primary: A-T (upper right 2nd molar to lower right 2nd molar)

Palmer Notation

Quadrant symbols (┘└ ┐┌) with tooth numbers

Permanent: 1-8 per quadrant

Primary: A-E per quadrant

FDI System

Two-digit system (quadrant + tooth)

First digit (quadrant):

• 1-4: Permanent teeth
• 5-8: Primary teeth

Second digit: Tooth number (1-8 or A-E)

Components

• Gingiva: Gum tissue (mucosa covering alveolar bone)
• Periodontal ligament: Fibrous tissue connecting tooth to bone (0.2mm width)
• Cementum: Calcified tissue covering root (softer than enamel)
• Alveolar bone: Tooth socket (cortical and cancellous)

Functions

• Support teeth
• Absorb chewing forces
• Provide sensory feedback
• Nutritive function

Biologic width: 2.04mm average (connective tissue + epithelial attachment)

Clinical Features

• Marginal Gingiva: Unattached collar around tooth (0.5-2mm wide)
• Attached Gingiva: Firmly bound to underlying bone (1-9mm wide)
• Interdental Papilla: Gingiva between teeth (pyramidal or col-shaped)
• Free gingival groove: Demarcates free from attached gingiva

Microscopic Features

• Oral epithelium: Parakeratinized stratified squamous
• Sulcular epithelium: Nonkeratinized
• Junctional epithelium: Forms attachment to tooth
• Gingival fibers: Dentogingival, circular, transseptal etc.

Stippling: Due to connective tissue projections

Gross Anatomy

• Dorsum: Upper surface (anterior 2/3 and posterior 1/3)
• Ventral: Undersurface (thin mucosa)
• Lateral borders: Sides
• Median sulcus: Midline groove
• Foramen cecum: Remnant of thyroglossal duct
• Lingual tonsils: Posterior lymphoid tissue

Papillae Types

• Filiform: Most numerous, conical shape (mechanical)
• Fungiform: Mushroom-shaped, contain taste buds
• Circumvallate: 8-12 large papillae at posterior, contain taste buds
• Foliate: Lateral folds, contain taste buds

Major Glands

• Parotid: Largest (25g), serous secretion, Stensen's duct
• Submandibular: Mixed secretion (70% total saliva), Wharton's duct
• Sublingual: Smallest (3g), mucous secretion, ducts of Rivinus

Minor Glands

• Labial, buccal, palatal, lingual
• 500-1000 glands throughout oral mucosa
• Produce 10% total saliva

Saliva Composition

• 99.5% water
• 0.5% solids (electrolytes, proteins, enzymes)
• pH 6.0-7.0 (resting), 7.4-8.0 (stimulated)
• Daily secretion: 500-1500ml

Functions

• Lubrication (mucins)
• Digestion (amylase, lipase)
• Antimicrobial (lysozyme, lactoferrin)
• Buffering (bicarbonate)
• Taste (solubilizes food)

Anatomy

• Articular surfaces: Mandibular condyle and articular fossa
• Articular disc: Fibrocartilage dividing joint into upper/lower compartments
• Capsule: Fibrous tissue enclosing joint
• Ligaments: Lateral, stylomandibular, sphenomandibular

Movements

• Hinge: Lower compartment (first 20mm opening)
• Gliding: Upper compartment (beyond 20mm)
• Protrusion/retrusion
• Lateral excursions

Clinical Notes

• Most used joint in body
• Only bilateral joint that must move simultaneously
• Disc displacement common pathology
• Bruxism can cause TMJ dysfunction

Accessory Muscles

• Suprahyoids (digastric, mylohyoid, geniohyoid)
• Infrahyoids (sternohyoid, omohyoid)
• Buccinator (facial nerve VII)

Clinical Correlation

• Trismus: Muscle spasm limiting opening
• Bruxism: Excessive muscle activity
• Myofascial pain: Trigger points

Arterial Supply

• Maxillary artery (external carotid branch):
  • Inferior alveolar artery
  • Buccal artery
  • Posterior superior alveolar
  • Infraorbital artery
  • Greater palatine artery
• Lingual artery (tongue supply)
• Facial artery (submental, inferior labial)

Venous Drainage

• Pterygoid venous plexus → maxillary vein
• Lingual vein → internal jugular
• Facial vein → common facial vein

Clinical Significance

• Bleeding during extractions
• Spread of infection via veins
• Anesthesia considerations

Trigeminal Nerve (V)

• V1 Ophthalmic: Sensory to upper face
• V2 Maxillary:
  • PSA, MSA, ASA (teeth)
  • Greater palatine (hard palate)
  • Nasopalatine (anterior palate)
  • Infraorbital (maxillary anterior)

Trigeminal (continued)

• V3 Mandibular:
  • Inferior alveolar (mandibular teeth)
  • Lingual (tongue anterior 2/3)
  • Buccal (cheek mucosa)
  • Mental (chin/lower lip)
• Motor branches: Muscles of mastication

Other Nerves

• Facial (VII): Taste anterior 2/3 tongue
• Glossopharyngeal (IX): Posterior 1/3 tongue
• Hypoglossal (XII): Tongue muscles

Autonomic Innervation

• Parasympathetic: Salivation (VII, IX)
• Sympathetic: Vasoconstriction

Primary Nodes

• Submental: Chin, lower lip, tongue tip
• Submandibular: Most oral structures
• Jugulodigastric: Tongue base, tonsils
• Retropharyngeal: Posterior pharynx

Drainage Pathways

• All eventually drain to deep cervical nodes
• Left: Thoracic duct
• Right: Right lymphatic duct

Clinical Significance

• Metastasis from oral cancers
• Infection spread
• Diagnostic palpation

Stages

1. Bud stage: Dental lamina proliferation (week 6-8)
2. Cap stage: Enamel organ formation (week 9-10)
3. Bell stage: Morphodifferentiation (week 11-12)
4. Apposition: Matrix deposition (week 18+)
5. Maturation: Mineralization

Tissues

• Enamel organ: Forms enamel
• Dental papilla: Forms dentin/pulp
• Dental sac: Forms cementum/PDL/alveolar bone

Eruption Sequence

• Primary: 6-30 months
• Permanent: 6-12 years (except 3rd molars)
• Root completion 2-3 years post-eruption

Clinical Correlation

• Developmental anomalies
• Impacted teeth
• Supernumerary teeth

Key Terms

• Occlusion: Contact between teeth
• Centric occlusion: Maximum intercuspation
• Centric relation: Condyles in most superior position
• Overjet: Horizontal overlap (2-4mm normal)
• Overbite: Vertical overlap (10-20% normal)
• Curve of Spee: Anteroposterior curve
• Curve of Wilson: Mediolateral curve

Angle's Classification

• Class I: Normal molar relationship
• Class II: Mandibular deficiency (Division 1/2)
• Class III: Mandibular excess

Malocclusion Effects

• TMJ disorders
• Periodontal problems
• Chewing difficulties

Masticatory Mucosa

• Gingiva and hard palate
• Keratinized stratified squamous
• Firmly attached to bone
• Resistant to abrasion

Lining Mucosa

• Cheeks, lips, floor of mouth
• Non-keratinized
• Loosely attached
• More flexible

Specialized Mucosa

• Dorsal tongue surface
• Contains papillae
• Combination of keratinized and non-keratinized

Clinical Correlation

• Leukoplakia/erythroplakia
• Ulcerations
• Burning mouth syndrome

Basic Tastes

• Sweet: Sugars (tip of tongue)
• Salty: Sodium ions (lateral tongue)
• Sour: Acids (lateral tongue)
• Bitter: Alkaloids (posterior tongue)
• Umami: Glutamate (distributed)

Taste Buds

• ~10,000 in adults
• Contain taste receptor cells
• Renew every 10-14 days
• Located in papillae (except filiform)

Neural Pathways

• Anterior 2/3: Chorda tympani (VII)
• Posterior 1/3: Glossopharyngeal (IX)
• Epiglottis: Vagus (X)
• To solitary nucleus → thalamus → cortex

Clinical Aspects

• Ageusia (loss of taste)
• Dysgeusia (altered taste)
• Side effects of medications

Secretion Mechanisms

• Parasympathetic: Watery saliva (acetylcholine)
• Sympathetic: Viscous saliva (norepinephrine)
• Unconditioned reflex: Direct stimulation
• Conditioned reflex: Anticipatory

Composition

• Inorganic: Na+, K+, Cl-, HCO3-, Ca2+
• Organic: Amylase, mucins, lysozyme, IgA
• pH 6.0-7.0 (resting), 7.4-8.0 (stimulated)

Functions

• Lubrication: Mucins (0.5-1g/dL)
• Digestion: α-amylase (starch), lingual lipase
• Protection: Antimicrobial proteins
• Buffering: Bicarbonate (pH regulation)
• Remineralization: Calcium/phosphate ions

Clinical Conditions

• Xerostomia (dry mouth)
• Sialolithiasis (stones)
• Sialadenitis (infection)

Teeth

• Attrition (wear of occlusal surfaces)
• Dentin sclerosis and transparency
• Pulp chamber reduction
• Root caries susceptibility

Periodontium

• Gingival recession
• Alveolar bone loss
• Periodontal ligament thinning
• Cementum thickening

Soft Tissues

• Mucosal thinning (epithelial atrophy)
• Decreased salivary flow
• Taste bud reduction (50% by age 60)
• Decreased tongue papillae

Functional Changes

• Reduced masticatory efficiency
• Swallowing difficulties
• Delayed wound healing
• Increased oral infections

Common Conditions

• Dental caries: Bacterial demineralization
• Periodontitis: Inflammatory bone loss
• Oral cancer: Squamous cell carcinoma
• Candidiasis: Fungal infection
• Aphthous ulcers: Recurrent painful lesions

Diagnostic Tools

• Radiographs (bitewing, periapical)
• Probing depths (periodontal exam)
• Salivary tests
• Biopsy (suspicious lesions)

Treatment Considerations

• Restorative materials (amalgam, composite)
• Local anesthesia techniques
• Periodontal therapy (scaling/root planing)
• Prosthetic options (implants, dentures)

Preventive Strategies

• Fluoride applications
• Sealants
• Oral hygiene instruction
• Regular recall visits

Case 1: Toothache

Presentation: 32-year-old with right mandibular pain

• Pain to cold and biting
• No visible caries
• Localized to tooth #30

Diagnosis: Cracked tooth syndrome

Treatment: Crown placement

Case 2: Bleeding Gums

Presentation: 45-year-old with bleeding when brushing

• Generalized redness
• 4-5mm pockets
• Calculus present

Diagnosis: Chronic periodontitis

Treatment: Scaling/root planing + oral hygiene instruction

Case 3: Dry Mouth

Presentation: 60-year-old on multiple medications

• Difficulty swallowing
• Burning sensation
• Increased caries

Diagnosis: Xerostomia (medication-induced)

Treatment: Saliva substitutes + fluoride

Case 4: Jaw Pain

Presentation: 28-year-old with TMJ clicking

• Pain on awakening
• Limited opening
• Bruxism history

Diagnosis: TMJ dysfunction

Treatment: Occlusal splint + muscle relaxants