Hydroxyapatite

An overview of hydroxyapatite and its applications in medicine and dentistry

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Hydroxyapatite
Hydroxyapatite crystal
General
Category	Phosphate mineral
Formula	Ca5(PO4)3(OH)
Strunz classification	[[Strunz classification|]]
Dana classification	[[Dana classification|]]
Crystal system	[[Crystal system|]]
Crystal class
Color
Physical properties
Cleavage
Mohs scale hardness
Luster
Streak
Diaphaneity
Specific gravity
Optical properties
Refractive index
Crystal habit
Other characteristics

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This template is designed for use on pages related to minerals, providing a standardized format to display essential information about various mineral properties. It includes fields for the mineral's name, image, category, formula, classifications (Strunz and Dana), crystal system and class, color, and various physical properties such as cleavage, hardness, luster, streak, diaphaneity, specific gravity, optical properties, refractive index, crystal habit, and other characteristics. Users can fill in the relevant information for each mineral, ensuring a consistent and informative presentation across the wiki's mineral-related articles.

Hydroxyapatite (HA) is a naturally occurring mineral form of calcium apatite with the formula Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>(OH). It is the main inorganic component of bone and tooth enamel, making it a critical material in biomedical applications.

Structure and Properties

Hydroxyapatite is a member of the apatite group, characterized by its hexagonal crystal structure. It is a calcium phosphate mineral with a high degree of crystallinity, which contributes to its hardness and stability. The chemical structure of hydroxyapatite is similar to that of the mineral component of bones and teeth, which is why it is often used in medical applications.

Applications in Medicine

Hydroxyapatite is widely used in the field of orthopedics and dentistry due to its biocompatibility and osteoconductivity. It serves as a scaffold for bone growth and is used in:

• Bone grafts: HA is used as a bone substitute material in bone grafting procedures. It supports the growth of new bone by providing a framework that mimics the mineral phase of bone.
• Dental applications: In dentistry, hydroxyapatite is used in toothpaste formulations to help remineralize enamel and reduce sensitivity. It is also used in dental implants and coatings to improve osseointegration.
• Coatings for implants: HA coatings are applied to metal implants to enhance their integration with bone tissue. This is particularly important in joint replacement surgeries.

Research and Development

Ongoing research is focused on improving the properties of hydroxyapatite for various applications. This includes the development of nano-sized hydroxyapatite particles, which have shown promise in enhancing the mechanical properties and bioactivity of composite materials.

Also see

• Bone grafting
• Dental implant
• Biomaterials
• Calcium phosphate

Gallery

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  Hydroxyapatite crystals

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  Hydroxyapatite crystal structure

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  Nanoscale coating of calcium hydroxyapatite