Objective: To investigate the effect of zirconia post and crown versus fibreglass post and crown restorations on gingival health in patients with extensive tooth defects. Methods: One hundred and two patients undergoing restoration for extensive tooth structure loss at our hospital between January 2022 and December 2024 were enrolled. Participants were randomly assigned using a random number table to either the zirconia post group (n=51) or the fibre post group (n=51). The zirconia post group received zirconia posts combined with zirconia crowns, while the fibre post group received fibre posts combined with zirconia crowns. At the six-month follow-up, the gingival bleeding index (BI), gingival index (GI), gingival crevicular fluid inflammatory markers [interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α)], periodontal pocket depth (PD), and clinical attachment level (CAL) were compared between the two groups before and after restoration. Additionally, the restoration loss rate and marginal adaptation were recorded.Results: Post-restoration, the fibre post group exhibited significantly lower BI, GI, IL-1β (26.58±5.41 pg/mL), TNF-α, PD, and CAL compared to the zirconia post group (P<0.05). Comparisons of prosthesis dislodgement rates (fibre post group: 3.92%; zirconia post group: 5.88%) and marginal adaptation (fibre post group: 92.16%; zirconia post group: 90.20%) revealed no statistically significant differences (P > 0.05). Conclusion: Fibreglass post-and-crown restoration with zirconia crowns demonstrates superior efficacy in improving gingival health compared to zirconia post-and-crown restoration in patients with extensive tooth structure loss. It significantly reduces gingival inflammatory response and warrants clinical preference.