Gingiva and Peri-implant tissue Flashcards
What is the structure of a typical screw?
Threaded - external connective with a hexagonal on the top (means crown cannot rotate on the top).
What happens to the bone when the implant is inserted?
Bone grows around the implant.
What is the periodontium?
What does it consist of?
- All the supporting structures of the tooth
- gingiva, periodontal ligament, cementum, alveolar bone
What does the peri - implant stature contain?
- All supporting structures of the implant
- the peri-implant mucosa, no periodontal ligament, no cementum, alveolar bone
Give details on the gingiva and its divisions
- part of the oral mucosa
- epithelial covering over connective tissue
- rapid epithelial turnover
- defined by tooth and mucogingival junction
- function: protection
Divided into 3 by position
1) attached gingiva
2) free gingiva
3) crevicular and junctional areas
Divided into two by structures:
1) epithelial elements
2) connective tissue elements
What measurement on the epithelium of the tooth always remains the same? What does this mean?
Connective tissue attachment.
If you do an implant too far down, the bone will start to be lost.
Attached gingiva:
- What type of mucosa is it?
- Where is it found?
- What is it bound to?
- pale pink, keratinised mucosa
- from mucogingival junction to free gingival groove
- firm and tightly bound onto bone
- striped (but not always)
Give the details on free gingiva
From free gingival groove to tooth.
Pale pink, keratinised, slightly loose and smooth
Give details on interdental gingival tissue: the papilla
Shapes varies depending on shape and size of teeth.
Where teeth are relatively narrow from buccal to lingual, the papilla is narrow also. The papilla is more like a tent shape at molars. This is called the COL.
It is pyramidal.
What are the 4 layers of the gingival epithelium?
Stratum basale
Stratum spinosum
Stratum granulosum
Stratum corneum
What does the gingival epithelium contain?
Contains melanocytes (the gums can have different colours - once a gum grows back it will be a light pink so need to think about this for people with lighter gums).
Langerhan’s cells – at most coronal part of juncnl epithelium:
- (Langerhans cells take up and process microbial antigens to become fully functional antigen-presenting cells. In severe infection, blood monocytes are recruited and differentiate into replacement)
Merkel cells
– sensory touch receptors in stratum basale:
– modified basal cells connected by desmosomes to neighbouring keratinocytes, associated with the presence of nerve endings – more common with inflammation / damage
– persist in the absence of teeth
Explain the crevicular & junctional epithelium
• crevicular epithelium
– keratinised
• junctional epithelium
• non-keratinised, basal & suprabasal cells
• large intercellular spaces:
– permeable to chemicals, cells and fluids
• rapid turnover: no cell differentiation / keratin / membrane coating granules
- firmly attached by HEMIDESMOSOMES – spot welds to protein layer on enamel (extended basal lamina) these hemidesmosomes attach to basal lamina and the tooth
How often is the junctional epithelium replaced?
Completely replaced every 4-6 days
Very rapid cell division and migration: all cells look like basal cells
Where does the gingival groove become thinner?
Towards the enamel (30 cells to 3 cells)
Explain the permeability of junctional epithelium dynamics
Cells and fluid from the connective tissue go into crevice.
Toxins and other bacterial produce enter into connective tissue.
What happens if you probe a inflamed junctional epithelium?
Probe enters further and will hurt. Site bleeds on probing.
Explain the junctional epithelium around implants/abutments
• It exists! And variable length
• It attaches to titanium of: – Implant surface
– Implant abutment surface
• Via:
– by HEMIDESMOSOMES
– Attached to basal lamina-like material on Ti surface
What is present in gingival connective tissue?
Glycosaminoglycans Collagen (type 1 and 3) Elastic Fibres Fibroblasts Blood vessels Lymph vessels Nerves
What are the 3 fibres which hold the gingiva down?
Alveolar crest fibres
Circular fibres
Dentoalveolar fibres
When an implant is put in, what tends to surround the implant in the alveolar bone?
Collagen
Give some features of the outer zone and inner zone of the tooth once an implant has been put in
Outer zone:
- Between bone & epithelium
- Multidirectional fibres
- Less collagen
- More cells & vessels
Inner zone:
- Contacting implant surface (50-100um thick)
- Fibre-rich 87% collagen
- Few cells and vessels
- Resembles scar tissue
What supply differs to a tooth when an implant comes in?
Blood supply
Give the details on different classifications of bone
- various classifications
- alveolar bone is that which makes up the alveolar ridge
- it is tooth dependant and has two types of bone in it:
1) Cortical (touching tooth)
2) Cancellous bone (outside of jaw) - 65% mineralised by weight
Give some differences between healthy teeth and healthy implants
1) Gingival sulcus depth
2) Junctional epithelium
3) Gingival fibres
4) Crest of bone
5) Connective tissue attachment
6) Physical characteristics
7) Adaptive characteristics
8) Proprioception
Healthy teeth:
1) shallow in health
2) on enamel
3) complex array inserted into cementum above crestal bone
4) 1 to 2mm apical to CEJ
5) Well organised collagen fibre bundles fibre bundles inserted as Sharpers fibres into alveolar bone and cementum
6) Physiologic mobility caused by viscoelastic properties of the ligament
7) Width of ligament can alter to allow more mobility with increased occlusal forces
8) Highly sensitive receptors present within the periodontal ligament
Healthy implants
1) Dependant upon abutment length and restoration margin
2) On titanium
3) No organised collagen fibre attachment - parallel fibres
4) According to implant design
5) Bone growing into close contact with implant surface
6) Rigid connection to bone
7) No adaptive capacity to allow mobility
8) No ligament receptors
