Bone resorption is a process that results in the transfer of calcium from bone fluid to bone. It occurs because of the breaking down of bone by osteoclasts due to which minerals are released. It helps in maintaining calcium levels in our blood.
Osteoclasts, the multi-nucleated cells containing numerous mitochondria and lysosomes, are responsible for the process of resorption. It is present just beneath the periosteum on the outer layer of the bone. It is also an essential component in tissue destruction that commonly occurs in psoriatic arthritis and other rheumatologically related disorders.
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What Is Bone Remodelling?
Bone remodeling is a process that continuously happens in our bodies throughout our entire life. In this process, discrete parts of old bones are replaced by newly synthesized packets of the proteinaceous matrix.
This helps in maintaining bone strength and ion homeostasis in our bodies. By process of ossification, osteoclasts resorb our bones, and osteoblasts deposit them. The action of osteocyte also plays an essential role in this process. The process of bone formation is more than resorption in the case of children.
But, as they grow up, the construction of bones in the body starts decreasing, and the resorption process starts dominating. Thus, in the case of adults, the process of resorption exceeds bone formation. Moreover, these rates are higher in the case of post-menopausal older women because of estrogen deficiency. Thus, they are advised to use drugs that can increase bone mineral density.
Some of the common treatments recommended for them include;
1. Bisphosphonates
2. RANKNL inhibitors
3. SERMs ( Selective Oestrogen Receptor Modulators)
4. Hormone replacement therapy
5. Calcitonin
The science behind the process of bone resorption
When the osteoclasts get attached to the osteon, the process of bone resorption begins. At first, the osteoclasts induces the infolding of its cell membranes, thus, secretes collagenase and other enzymes that help in the reabsorption process.
As osteoclasts tunnel into mineralized bone, high levels of calcium, magnesium, phosphate, and collagen products are released into the extracellular fluid. The organization of the actin cytoskeleton in osteoclasts helps in osteoclast migration and bone resorption.
The dynamic interaction between osteoclasts and extracellular matrix (ECM) is required for bone resorption and migration. This ECM made up of glycoproteins such as collagen, proteoglycans, and fibronectin is an intricate network of macromolecules on which cell migrates or adheres to the bone.
The attachment and movement of osteoclasts are facilitated by the assembly and disassembly of podosomes. Podosomes are F-actin- rich adhesive structures that degrade the extracellular matrix through local proteolysis and are used by osteoclasts for bone remodeling.
Also, sealing rings generated by osteoclasts help restore the bone upon addition to the bone matrix. These sealing rings are thicker and more stable as compared to podosomes. A complex array of hormonal influences and growth factors that create communication between osteoclasts and osteoblasts regulates bone metabolism.
Reproductive hormones like estrogen, progesterone, and testosterone play an essential role in the Hypothalamic-Pituitary-Gonadal Axis. The Growth Hormone/Insulin Growth Factor Axis directly influences cartilage expansion, bone modeling, and remodeling.
Is the bone resorption process harmful to our body?
The increase in the process of ossification or the number of osteoclasts can decrease bone mass. Also, the abnormal increase in osteoclasts activity that increases bone resorption can cause osteoporosis and other bone loss associated diseases.
Osteoporosis
This condition arises in the body when bones become so weak and brittle that even a fall or mild stresses cause a fracture in them. It occurs in the hip, spine, or wrist.
Osteoporosis commonly occurs in the body when the creation of new bone doesn’t happen in coordination with the loss of old bone.
The common symptoms associated with osteoporosis include;
1. Back pain
2. Stooped posture
3. Easy breakage of bones
4. Height loss
Consuming a healthy diet and medications and performing weight-bearing exercises regularly can help prevent bone loss or strengthen weak bones.
Effects of bone resorption on oral health
Bone resorption is a necessary process that happens in our bodies. It might sound like an odd process, but it is essential for maintaining our body and oral health.
For example, this process helps to breakdown the bones that are left behind our milk teeth when they fall off so that a room for permanent teeth can be created. Braces use the foundation of ossification to work.
They control the flow of ossification by pressure and trick your body to move the teeth by breaking down the bone holding the teeth and moving them in the direction we want by recreating them. But, in some instances, the occurrence of bone resorption can be harmful to our body.
Few issues to consider under this situation are;
1. If teeth are extracted, and space is left behind, bone resorption and jawbone loss occur.
2. If someone loses teeth under an accident or severe tooth decay, bone resorption occurs because of the loss of stimulus and receiving impact from surrounding teeth.
3. There are some tissues and bones that hold a tooth in its place. An abundance of plaque and inflammation in the gum line can break down these tissues that eventually cause bone resorption.
The process of bone resorption happens in two sites of our roots.
1. External bone resorption – It develops at the tooth’s exterior, at the site where the tooth is connected with the jawbone.
2. Internal bone resorption – This happens within the tooth because of chronic inflammation in the tooth’s pulp. It is easier to treat internal bone resorption. But, solving external bone resorption is more complicated and is done with a root canal or tooth extraction.
In the surgery, a portion of the damaged root is extracted due to the bone resorption stops. If one doesn’t want to go through the extraction process, a tooth prosthetic is also an option. The choice is entirely yours.
Also, sometimes, a person does need bone resorption, but he isn’t aware of it. Losing a tooth is always a horrific thought, which is why one should always keep an option.