Oral surgery L2: Bone biology bone and calcium Flashcards
Q1: what percentage of bone composition is mineral?
60% mineral, largely hydroxyapatite
Q2: what percentage of bone composition is organic?
25% organic (90% type 1 collagen)
Q3: what percentage of bone composition is water? 15% water
Q4: which bone supports the tooth?
Alveolar bone

Q5: which bone takes the shape of the mandible/maxilla?
basal bone

Q6: why is infiltration of lidocaine on the lower 6 hard to achieve anaesthesia?
The bone is very dense and thick in that region, which doesn’t allow diffusion of the anaesthetic.
Q7: why is infiltration more appropriate in the maxilla compared to the mandible?
More trabecular bone present in the maxilla compared to the lower, this allows better diffusion of anaesthetic material through the bone.
Q8: which region in the maxilla will you begin to find challenging to achieve anaesthesia through infiltration and why?
You would start to struggle to achieve anaesthesia in the upper 6, this is due to the presence of the zygomatic process, which is allot thicker.
Q9: the lamina dura is also known as bundle bones due to the presence of bundle of collagen fibres. the lamina dura acts as a cribriform plate, this feature allows us to achieve anaesthesia by which technique?
Intraligamentary technique.
Q10: where is the circumferential lamellae located.


Q11: where is the concentric lamellae located.


Q12: where is the interstitial lamellae located.


Q13: cartilage –> calcified cartilage –>bone. What type of ossification is this?
Endochondral ossification.
Q14: trapped osteoblasts are called what?
Osteocytes
Q15: which two hormones help regulate calcium homeostasis?
Calcitonin and parathyroid hormone.
Q16: which thyroid hormone increases plasma calcium levels?
Parathyroid hormone
Q17: which thyroid hormone decreases plasma calcium?
Calcitonin
Q18: which hormone acts on the kidneys to decrease Ca excretion?
Parathyroid hormone
Q19: which hormone acts on the kidneys to increase Ca excretion?
Calcitonin
Q20: if there is a decrease in plasma calcium levels, the parathyroid hormone acts to release calcium in the plasma. It can do this fast and slow, how do osteocytes help in fast deliverance of Ca2+ in the plasma.
Osteocytes are osteoclasts trapped in bone, which are surrounded by blood vessels. In the bone there are small labile pools of Ca2+, the osteocytes undergo osteocytic osteolysis, which breaks down the small amount of bone and due to the proximity of the blood vessels, it delivers it directly to the plasma.
Q21: if there is a decrease in plasma calcium levels, the parathyroid hormone acts to release calcium in the plasma. It can do this fast and slow, how does the slow process work.
It works by bone dissolution and shifts remodelling to favour resorption.
Q22: trapped osteoclast are known as osteocytes, are osteocytes vital or non vital?
They are vital