Hydroxyapatite/Collagen Composite Is a Reliable Material for Malar Augmentation. 
To evaluate the long-term results of cheekbone augmentation using porous hydroxyapatite granules mixed with microfibrillar collagen in a large group of patients.  Four hundred thirty patients who underwent zygomatic augmentation and intermaxillary osteotomy were evaluated clinically, radiologically, and histologically.  Complications were found in 13 patients (1.56%).  There were no relevant radiologic differences in prosthesis volume after 1 month (T1) or after 24 months (T2) in any patient; there were no clinically relevant differences in 110 patients after 36 months.  At T1, the prosthesis had a granular structure and the granules had not migrated; at T2, the prosthesis was staunchly adhering to the underlying bone.  Over time, the radiopacity of the material increased.  Histologic results of 19 biopsy specimens obtained from 8 patients 2 years after the procedure showed prominent ossification with low inflammation, confirming new bone formation over time.  According to the visual analog scale, the patients were generally satisfied with the aspects that were considered.  Hydroxyapatite and collagen composite used during malarplasty produced a successful outcome.  Its main drawback is a learning curve that is longer than for more frequently used implantable biomaterials.