Table 2.

Detailed overview of in vivo studies on PRP and HAp for bone regeneration, including outcome analysis and relevance to the current clinical study, organized chronologically from the earliest to the most recent publications.

Study	Species	Defect type	PRP/HAp application	Outcome	Comments
Kon et al., 2010 (20)	Sheep	Osteochondral	Collagen-HAp scaffold + PRP	PRP decreased the osteochondral regeneration capability of the scaffold	The combination of PRP and scaffold led to highly amorphous cartilaginous repair tissue underlying bone tissue.
Yamada et al., 2010 (14)	Dog	Bone defects—dental implant	PRP + Dental pulp stem cells	Promoted bone regeneration	Shows the potential of PRP in combination with stem cells for enhanced bone healing.
Knapen et al., 2013 (21)	Rabbits	Bone regeneration	L-PRF (a variant of PRP)	No significant effect on bone regeneration	Contrasts with this study’s positive outcome, suggesting that different PRP formulations may yield varied results.
Zhang et al., 2020 (17)	Rats	Critical-size calvarial defects	PRP + ADSC and HAp	Enhanced bone formation and defect closure	Demonstrates synergistic effects of PRP and HAp on bone healing in critical-size defects primarily treated with ADSC
Jiang et al., 2021 (18)	Rabbits	Osteochondral	3D-printed PRP-GelMA hydrogel	Promoted osteochondral regeneration through M2 macrophage polarization	Enhanced migration, proliferation, and differentiation of BMSCs, and improved cartilage and subchondral bone regeneration.
Henkel et al., 2021 (22)	Sheep	Large volume tibial segmental defects	mPCL-TCP scaffolds with PRP and rhBMP-7	Promoted bone regeneration at both short-term and long-term time points	Large volume tibial defects in sheep are treated with varying degrees of success in bone regeneration and mechanical integration.
Lee et al., 2018 (16)	In vitro	Bone regeneration	PRP + HAp scaffold (Ca-deficient)	Enhanced bone regeneration	Demonstrates the effectiveness of PRP combined with Ca-deficient HAp to favor osteoblast proliferation.
Venkataiah et al., 2021 (25)	Various mammals	Bone defects	Cell-scaffold constructs with PRP	Promoted bone regeneration	This work further supports the clinical applicability.
Rapone et al., 2022 (23)	Humans	Maxillary sinus augmentation	Algipore (HAp) and PRP	Predictable long-term results; comparable to Bio-Oss without PRP	The potential of PRP in clinical settings is highlighted, although focused on a different bone lesion type.
Inchingolo et al., 2022 (24)	Various	Bone defects regeneration	Engineered grafts with PRP	Enhanced bone regeneration	Reinforces the concept of PRP-enhanced grafts for bone healing akin to this study’s use of HAp.
Sharun et al., 2023 (19)	Rabbits	Atrophic non-union fractures	PRP and AdSVF	Improved healing in orthopedic conditions	Supports this study’s findings by demonstrating PRP’s effectiveness in a different animal model.