Periodontitis is a chronic inflammatory disease characterized by plaque biofilm dysbiosis, immune dysregulation, oxidative stress, alveolar bone resorption, and impaired wound healing. Although conventional periodontal therapies can reduce microbial burden and slow disease progression, predictable regeneration of the cementum-periodontal ligament (PDL)-alveolar bone complex remains difficult in irregular, infected, and inflammation-compromised defects. Three-dimensional (3D) printing offers a programmable strategy for fabricating periodontal scaffolds with patient-specific geometry, tunable pore architecture, spatially distributed materials, and region-specific biological functions. This review summarizes recent advances in 3D-printed scaffolds for periodontitis therapy and periodontal tissue regeneration, with emphasis on spatial programming and microenvironmental regulation. We first analyze the pathological barriers dictating scaffold design requirements, including persistent biofilms, unresolved inflammation, oxidative stress, disrupted bone homeostasis, and defective healing. We then discuss major printing modalities, material platforms, and biomimetic design strategies, including patient-specific customization, multiphasic compartmentalization, PDL fiber guidance, vascularization-oriented pore networks, and integrated barrier control. Functional strategies involving antibacterial activity, immuno-redox regulation, tissue-specific regenerative cues, neurovascular support, and spatiotemporal delivery are highlighted. Finally, we outline challenges in material optimization, disease-relevant modelling, functional evaluation, manufacturing standardization, and clinical translation. Future 3D-printed periodontal scaffolds should evolve from passive defect fillers into microenvironment-driven precision regenerative systems for functional periodontal reconstruction.