Spongy bone

Spongy Bone

1. GUIDED BY: DR MOHSIN GHANCHI MDS DR VIKAS BHASKHAR MDS PRESENTED BY ARBAZKHAN PATHAN 1 ST YEAR BDS ROLL NO 42

2. SEMINAR TOPIC SPONGY BONE

3. INTRODUCTION Spongy bone and compact bone have the same cells and intercellular matrix, but differ in the arrangement of components. Spongy bone looks like a poorly organized tissue in contrast to compact bone. The bony substance consists of large slender spicules called trabeculae . The trabuculae are oriented along lines of stress to withstand the forces applied to bone The marrow space are large. The trabeculae surround the marrow spaces from where they derive their nutrition

4. Spongy bone fills the area between the cortical plates and the aleolar bone proper. The study of roentgenograms permits the classification of the spongiosa of the alveolar process into two main types

5. Tpes of the spongy bone The interdental and interradicular trabeculae are regular and horizontal in a ladderlike arrangement . Both types show a variation in thickness of trabeculae and size of marrow spaces It shows irreguralarly arranged, numerous, delicate interdental and interradicular trabeculae . Both types show a variation in thickness of trabeculae and size of marrow spaces TYPE 1 TYPE 2

6. Tpes of the spongy bone The architecture of TYPE 1 is seen often in the mandible and fits well into the general idea of the trajectory pattern of spongy bone TYPE 2, although evidently fuctionally satisfactory, lacks a distict trajectory pattern, which seems to be compensated for by the grater number of trabeculae in any given area. TYPE 1 TYPE 2

7. This arrangement is more common in the maxilla. From the apical part of the socket of lower molars, trabeculae are sometimes seen radiating in a slightly distal direction. These trabeculae are less prominent in the upper jaw because of the proximity of the nasal cavity and the maxillary sinus. The marrow spaces in the alveolar process may contain haemopoietic marrow , but usually they contain fatty marrow. In the condylar process, in the angle of the mandible, in the maxillary tuberosity , and in other isolated foci, hematopoietic cellular marrow is found.

8. CLINICAL CONSIDERATION The adaptation of bone to function is quantitative as well as qualitative. Whereas, increase in functional forces leads to formation of new bone, decreased function leads to a decrese in the volume of bone. This can be observed in the supporting bone of teeth that have lost their antagonists. Here the spongy bone around the alveolus shows pronounced rarefaction. The bone trabeculae are less numerous and very thin. The alveolar bone proper, however, is generally well preserved because it continues to receive some stimuli from the tension of the periodontal tissues

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