Functional & Esthetic Crown Lengthening Flashcards

1
Q

Define Crown Lengthening

A
  • lengthen crown of teeth
  • removal of:
    • only soft tissue (Gingivectomy)
    • Only hard tissue (osteotomy/osteoplasty)
    • BOTH
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2
Q

What are the different types of Crown lengthening

A
  • Esthetic
  • Functional
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3
Q

Esthetic Crown Lengthening

A
  • increase crown length
    • mainly anterior teeth
  • achieve ideal esthetic proportions
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4
Q

Functional Crown Lengthening

A
  • increase crown length
  • for new crown or restoration
    • w/better resistance and retention
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5
Q

Crown Lengthening: Indications

A
  • Improve unesthetic appearance
    • delayed/altered passive eruption
  • Restoration
    • fractured or Caries
      • at the level of gingiva OR
      • extending sub-g
  • Placing SUB-G restoration
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6
Q

Biologic Width: Supracrestal Attached Tissues

A
  • the space b/w the base of the sulcus and alveolar bone
    • healthy gingiva occupy
  • 2.04 mm=JE + CT
    • combined width of Junctional epithelium (JE) + Connective tissue attachment (CT)
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7
Q

What are the supracrestal attached tissues?

A
  • Junctional epithelium
  • Connective tissue
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8
Q

How does violating the Biologic Width happen?

A
  • restoration placed < 2mm from alveolar bone margin
  • inflamed gingival tissues
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9
Q

What can violating the biological width lead to?

A
  • Inflammation
    • more common with deep margin placement
    • Normal to thick biotypes
    • No bone loss
  • Bone Loss
    • Thin biotypes/phenotypes
    • unpredictable bone loss and gingival recession
      • body tries to regain space b/w restoration margin and alveolar bone for tissue reatachment
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10
Q

Critical Perio-Restorative Zones

A
  • where the periodontium interacts w/restorations
  • Ferule Effect
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11
Q

Ferule Effect

A
  • abutment provides enough tooth structure for the ferrule or crown to grab onto
    • resistant to fracture
      • 1.5-2.0 mm above projected ferule margin
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12
Q

Clinical Implications: Depth

A
  • Deep restoration margins
    • violate biologic width
    • avoid
  • Depth affects the:
    • accuracy of making impression
    • marginal fit of restoration
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13
Q

Clinical Implications: Marginal Fit

A
  • Open margins
    • harbor bacteria
    • lead to inflammation
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14
Q

Clinical Implications: Contour

A
  • Overcontoured restorations
    • negative impact on oral hygiene practices
    • leads to inflammation
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15
Q

Altered Passive Eruption

A
  • free gingival margin does not recede during tooth eruption
    • above cervical convexity of clinical crown
  • on convex prominence of enamel
    • instead of CEJ
  • Types:
    • Type 1=Excessive Gingiva
    • Type 2=Normal amount of gingiva
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16
Q

Altered Passive Eruption: Type 1 vs Type 2

A
  • Type 1: Excess Gingiva
    • 1A
      • Normal CEJ/alveolar crest relationship (Crest below CEJ)
        • Gingivectomy
    • 1B:
      • Alveolar Creat at the CEJ
        • gingivectomy + Osseous surgery
  • Type 2:Normal amount of Gingiva
    • 2A
      • Normal CEJ/Alv crest relationship
        • Apically position flap (APF)
    • 2B
      • Alveolar crest at the CEJ
        • APF + OSS surgery
17
Q

Ideal Gingival Contours

A
  • Right Side of mouth is symmetrical to Left
  • Line Drawn from gingival crest of cuspids
    • parallel to interpupillary line
  • Gingival Margins:
    • incisors→ symmetrical
    • height of contour
      • slightly distal to midline of the tooth
    • Lateral Incisors:
      • 0.5-1.0 mm coronal to central incisors margin
    • Canines:
      • align with central incisors
18
Q

What is the ideal maxillary central incisor proportion?

A
  • 80% width compared to height
19
Q

What can be used to determine a tooth dimension?

A
  • T-Bar Proportion gauge
20
Q

What is the general trend for average tooth proportions based on gender? (maxillary Anterior teeth)

A
  • Males
    • wider and longer compared to female
21
Q

healing after crown lengthening: Timeline of events(formation)

A
  • Epithelial cells migrate 0.5mm/day
  • Formation of:
    • New junctional epithelium
      • 2 weeks
    • immature connective fibers:
      • 2-3 weeks
    • Cementum
      • 6-8 weeks
  • @ 8 weeks
    • mature junctional epithelium + Connective tissue attachement
    • incorporated into cementum
22
Q

healing after crown lengthening: Gingival Margin

A
  • Gingival margin:
    • moves coronally
    • direction depends on thickness of tissue/tissue biotype (NOT age or gender)
      • Thick biotype
        • coronal movement
      • Thin Biotype:
        • apical movement (Recession)
23
Q

Healing after crown lengthening: Buccal Plate

A
  • Thickness of buccal plate
    • contributes to coronal migration of gingiva
  • Thin Buccal Plate (<2mm)
    • recession
24
Q

Clinical Consideration: Thin gingival tissue

A
  • longer wait before restoring
  • avoid gingival recession