*Review* **Bioactive Calcium Phosphate-Based Composites for Bone Regeneration**

**Marta Tavoni †, Massimiliano Dapporto \*,†, Anna Tampieri and Simone Sprio \***

Institute of Science and Technology for Ceramics—National Research Council of Italy (ISTEC-CNR), 48018 Faenza, Italy; marta.tavoni@istec.cnr.it (M.T.); anna.tampieri@istec.cnr.it (A.T.)

**\*** Correspondence: massimiliano.dapporto@istec.cnr.it (M.D.); simone.sprio@istec.cnr.it (S.S.);

Tel.: +39-0546699760 (M.D.)

† Co-first author, these authors contributed equally to this work.

**Abstract:** Calcium phosphates (CaPs) are widely accepted biomaterials able to promote the regeneration of bone tissue. However, the regeneration of critical-sized bone defects has been considered challenging, and the development of bioceramics exhibiting enhanced bioactivity, bioresorbability and mechanical performance is highly demanded. In this respect, the tuning of their chemical composition, crystal size and morphology have been the matter of intense research in the last decades, including the preparation of composites. The development of effective bioceramic composite scaffolds relies on effective manufacturing techniques able to control the final multi-scale porosity of the devices, relevant to ensure osteointegration and bio-competent mechanical performance. In this context, the present work provides an overview about the reported strategies to develop and optimize bioceramics, while also highlighting future perspectives in the development of bioactive ceramic composites for bone tissue regeneration.

**Keywords:** calcium phosphates; hydroxyapatite; scaffolds; bone cements; bioactive composites; bone regeneration
