Dental Arch Morphology and Periodontal Anatomy

Definition: The arrangement of teeth in the upper (maxillary) and lower (mandibular) arches.
Types:
- Quadrant: Each arch is divided into two quadrants, resulting in four total quadrants.
- Dental Curve:
  - Curve of Spee: Anteroposterior curvature from anterior to posterior teeth.
  - Curve of Wilson: Buccolingual curvature in the posterior teeth.
Arch Forms:
- U-shaped: Characteristic of most maxillary arches.
- V-shaped: Typical of narrower mandibular arches.
Arch Length and Width: Influences bite relationships and overall dental health.

Periodontium Components:
- Gingiva: Mucosal tissue surrounding the teeth; protects underlying structures.
- Periodontal Ligament (PDL): Connective tissue attaching teeth to alveolar bone.
- Cementum: Hard tissue covering the tooth root, aiding attachment to the PDL.
- Alveolar Bone: Bone that supports and surrounds the teeth.
Types of Gingiva:
- Free Gingiva: The unattached portion surrounding the teeth.
- Attached Gingiva: Gingiva firmly bound to the underlying alveolar bone.
Clinical Considerations: Health of the periodontium is critical for preventing periodontal disease.

Enamel:
- Hard, outermost layer; protects against decay.
- Composed mainly of hydroxyapatite crystals.
Dentin:
- Underlies enamel; less hard than enamel.
- Contains tubules that transmit sensations.
Pulp:
- Innermost part; contains nerves and blood vessels.
- Vital for tooth vitality and sensation.
Cementum:
- Covers the root; assists in tooth stability.
- Less mineralized than enamel and dentin.

Definition: The way upper and lower teeth come together when the mouth closes.
Types of Occlusion:
- Class I: Normal relationship; molars aligned properly.
- Class II: Retrognathic; upper molar is more forward than lower.
- Class III: Prognathic; lower molar is more forward than upper.
Functional Occlusion:
- Refers to the bite during activities such as chewing.
Importance: Proper occlusion is essential for effective chewing, speech, and overall oral health.

Tooth Types:
- Incisors: Sharp edges for cutting; 8 total (4 upper, 4 lower).
- Canines: Pointed teeth for tearing; 4 total (2 upper, 2 lower).
- Premolars: Flat surfaces for grinding; 8 total (4 upper, 4 lower).
- Molars: Large, flat surfaces for grinding; 12 total (6 upper, 6 lower).
Universal Numbering System:
- Each tooth is assigned a specific number (1-32).
Identification Features:
- Crown: Visible part above the gum line.
- Root: Part embedded in alveolar bone.
- Anatomical landmarks: Cusps, ridges, and grooves help differentiate tooth types.

Arrangement of teeth in the maxillary (upper) and mandibular (lower) arches.
Divided into quadrants: Each arch has two quadrants, totaling four quadrants.
Curve of Spee: Anteroposterior curvature that runs from the anterior to posterior teeth.
Curve of Wilson: Buccolingual curvature observed in posterior teeth.
Arch Forms:
- U-shaped is typical for maxillary arches, while V-shaped is common in narrower mandibular arches.
Arch length and width significantly impact bite relationships and overall dental health.

Periodontium Components:
- Gingiva: Mucosal tissue surrounding teeth, providing protection to underlying structures.
- Periodontal Ligament (PDL): Connective tissue anchoring teeth to the alveolar bone.
- Cementum: Hard tissue covering the tooth root, vital for attachment to the PDL.
- Alveolar Bone: Bone structure that supports and surrounds teeth.
Types of Gingiva:
- Free Gingiva: The unattached part around the teeth.
- Attached Gingiva: Firmly bound gingiva to the underlying alveolar bone.
Maintaining the health of the periodontium is crucial for preventing periodontal disease.

Enamel:
- The hardest outer layer that protects against decay, primarily composed of hydroxyapatite crystals.
Dentin:
- Lies beneath the enamel, less hard, with tubules that transmit sensation.
Pulp:
- Innermost part of the tooth containing nerves and blood vessels, essential for vitality and sensation.
Cementum:
- Covers the tooth root, providing stability; it is less mineralized compared to enamel and dentin.

Occlusion: Describes how upper and lower teeth align when the mouth closes.
Types of Occlusion:
- Class I: Normal occlusion where molars are properly aligned.
- Class II: Retrognathic occlusion with the upper molar positioned more forward than the lower.
- Class III: Prognathic occlusion with the lower molar positioned further forward than the upper.
Functional Occlusion: Refers to how the bite functions during activities like chewing.
Proper occlusion is vital for effective chewing, speech, and overall oral health.

Tooth Types:
- Incisors: Sharp edges for cutting; total of 8 (4 upper, 4 lower).
- Canines: Pointed teeth for tearing; total of 4 (2 upper, 2 lower).
- Premolars: Flat surfaces for grinding; total of 8 (4 upper, 4 lower).
- Molars: Large flat surfaces for grinding; total of 12 (6 upper, 6 lower).
Universal Numbering System: Each tooth is assigned a specific number ranging from 1 to 32.
Identification Features:
- Crown: Visible part above the gum line.
- Root: Portion embedded in the alveolar bone.
- Anatomical landmarks: Features such as cusps, ridges, and grooves aid in distinguishing different tooth types.