Gingiva and Peri-implant tissue

Question 1

What is the structure of a typical screw?

Answer 1

Threaded - external connective with a hexagonal on the top (means crown cannot rotate on the top).

Question 2

What happens to the bone when the implant is inserted?

Answer 2

Bone grows around the implant.

Question 3

What is the periodontium?

What does it consist of?

Answer 3

• All the supporting structures of the tooth

- gingiva, periodontal ligament, cementum, alveolar bone

Question 4

What does the peri - implant stature contain?

Answer 4

• All supporting structures of the implant

- the peri-implant mucosa, no periodontal ligament, no cementum, alveolar bone

Question 5

Give details on the gingiva and its divisions

Answer 5

• 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

Question 6

What measurement on the epithelium of the tooth always remains the same? What does this mean?

Answer 6

Connective tissue attachment.

If you do an implant too far down, the bone will start to be lost.

Question 7

Attached gingiva:

• What type of mucosa is it?
• Where is it found?
• What is it bound to?

Answer 7

• pale pink, keratinised mucosa
• from mucogingival junction to free gingival groove
• firm and tightly bound onto bone
• striped (but not always)

Question 8

Give the details on free gingiva

Answer 8

From free gingival groove to tooth.

Pale pink, keratinised, slightly loose and smooth

Question 9

Give details on interdental gingival tissue: the papilla

Answer 9

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.

Question 10

What are the 4 layers of the gingival epithelium?

Answer 10

Stratum basale
Stratum spinosum
Stratum granulosum
Stratum corneum

Question 11

What does the gingival epithelium contain?

Answer 11

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

Question 12

Explain the crevicular & junctional epithelium

Answer 12

• 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

Question 13

How often is the junctional epithelium replaced?

Answer 13

Completely replaced every 4-6 days

Very rapid cell division and migration: all cells look like basal cells

Question 14

Where does the gingival groove become thinner?

Answer 14

Towards the enamel (30 cells to 3 cells)

Question 15

Explain the permeability of junctional epithelium dynamics

Answer 15

Cells and fluid from the connective tissue go into crevice.

Toxins and other bacterial produce enter into connective tissue.

Question 16

What happens if you probe a inflamed junctional epithelium?

Answer 16

Probe enters further and will hurt. Site bleeds on probing.

Question 17

Explain the junctional epithelium around implants/abutments

Answer 17

• 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

Question 18

What is present in gingival connective tissue?

Answer 18

Glycosaminoglycans
Collagen (type 1 and 3)
Elastic Fibres
Fibroblasts
Blood vessels 
Lymph vessels
Nerves

Question 19

What are the 3 fibres which hold the gingiva down?

Answer 19

Alveolar crest fibres
Circular fibres
Dentoalveolar fibres

Question 20

When an implant is put in, what tends to surround the implant in the alveolar bone?

Answer 20

Collagen

Question 21

Give some features of the outer zone and inner zone of the tooth once an implant has been put in

Answer 21

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

Question 22

What supply differs to a tooth when an implant comes in?

Answer 22

Blood supply

Question 23

Give the details on different classifications of bone

Answer 23

• 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

Question 24

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

Answer 24

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