Asian Journal of Dental Sciences

Zirconia and lithium disilicate now dominate the ceramic landscape of fixed partial denture (FPD) prosthodontics, prized for their mechanical resilience, optical qualities and generally favourable behaviour at the soft-tissue margin compared with older metal-ceramic systems. Diabetes mellitus, meanwhile, has become one of the most common chronic metabolic disorders worldwide, and its well-documented two-way relationship with periodontal disease inevitably complicates the long-term prognosis of any fixed restoration placed in an affected patient. This critical review brings together the available evidence on how zirconia and lithium disilicate FPDs are tolerated by periodontal and peri-implant soft tissue, paying particular attention to how the hyperglycaemic, pro-inflammatory, wound-healing-impaired state characteristic of diabetes might alter that response. It examines the material science behind surface roughness, biofilm affinity and marginal adaptation in both ceramics; the periodontal implications of margin location and biologic width; survival and complication data for tooth- and implant-supported reconstructions; and the reciprocal clinical relevance of periodontal and prosthodontic therapy for glycaemic control. Taken as a whole, the literature indicates that both ceramics are generally well tolerated by periodontal tissue in metabolically healthy patients, but that diabetes—especially when poorly controlled—is linked to higher rates of biological complications, greater peri-implant bone loss and shorter prosthesis survival, with glycaemic status proving a stronger determinant of outcome than the choice of ceramic itself. The evidence base remains constrained by considerable heterogeneity, very few comparative trials conducted specifically in diabetic populations, and a continued reliance on extrapolation from the broader implant and periodontal literature, limitations that define clear priorities for future research.