Mandibular bone response to plasma-sprayed coatings of hydroxyapatite

Area of Science:

• Biomaterials Science
• Orthopedic Research
• Dental Implantology

Background:

• Titanium implants are widely used in bone reconstruction.
• Hydroxyapatite coatings enhance osseointegration.
• Plasma-spraying offers a method for applying ceramic coatings.

Purpose of the Study:

• To evaluate the biological and mechanical properties of plasma-sprayed hydroxyapatite coatings on titanium substrates.
• To assess the bone-implant interface strength and osseointegration.
• To compare the performance of plasma-sprayed hydroxyapatite with sintered hydroxyapatite.

Main Methods:

• Application of hydroxyapatite coating on titanium substrates using plasma spraying.
• Implantation of coated titanium in a canine mandibular model.
• Assessment of implant-bone bonding using radiologic, macroscopic, and microscopic analyses.
• Evaluation of shear strength at the bone/ceramic and ceramic/titanium interfaces.

Main Results:

• A strong, direct bond formed between the hydroxyapatite coating and mandibular bone.
• The shear strength at the bone/ceramic interface exceeded that of the ceramic/titanium interface.
• Radiologic, macroscopic, and microscopic observations confirmed excellent osseointegration.
• Some mechanical failure of the outer coating layer led to free hydroxyapatite particles in surrounding tissue.

Conclusions:

• Plasma-sprayed hydroxyapatite coatings demonstrate comparable biological properties to sintered hydroxyapatite.
• The coating provides robust bone integration and high interfacial shear strength.
• Potential for mechanical delamination of the coating warrants further investigation for long-term stability.