1. Cementum

2. Cementum Least highly mineralised tissue of the tooth
Covers the entire root surface
Two main types:
Acellular Cementum
Cellular Cementum
No cells present in the acellular
There are cells present in the cellular – Cementocytes
The cells that form both – Cementoblasts

3. Cementum Acellular cementum covers the entire root surface
Lies next to the outer surface of the dentine
Cementoblasts lie next to the outer surface of the dentine
Start to form cementum – this will be acellular – very slowly
Organic matrix, mainly collagen, along with a ground substance is laid down first, and is subsequently mineralised

4. Cementum The fibres, referred to as intrinsic fibres, are very small
These fibres are aligned parallel to root surface
Is the means by which the fibres of the periodontal ligament (PDL) are attached to the tooth
Collagen fibres of the PDL are inserted into the cementum
These (second type) are referred to as the extrinsic fibres

5. Cementum Aligned perpendicular to the root surface
Formed by fibroblasts – originated from within the PDL
Cellular cementum – found usually around the apex of a single-rooted tooth and at both the apices and bi/trifurcation region of multi-rooted tooth
Formed much more rapidly than the acellular – probably the reason why cells are therefore ‘caught up’ in the tissue

6. Cementum
Cementocytes are no longer formative cells – exist permanently within lacunae within the cementum
Thin processes (canaliculi) point towards the PDL
Source of nutrition for both acellular and cellular cementum
During periodontal disease – there is loss of (PDL) attachment of the tooth to bone

7. Cementum Cementum in those areas becomes redundant
Should be removed during treatment
Has lost its source of nutrition and function, and so becomes merely a roughened source covering the outer surface of the root of a tooth
No function!
If not removed, will attract dental plaque and may encourage further loss of attachment of the tooth

8. Ground section of a tooth showing enamel, dentine, the pulpal cavity and cementum The cementum at the apex is thicker and will be made up mainly of cellular cementum

9.   Ground section of a root demonstrating dentine (A) and cellular cementum (B)