Survival rate and marginal bone loss in titanium vs titanium-zirconia single-unit narrow diameter implants. A systematic review and Meta-analysis of prospective studies.

Background: Implant-supported single-unit restorations present a predictable and widely used treatment option to replace missing teeth. Narrow-diameter implants provide a viable treatment option for clinical scenarios with limited bone availability, minimizing the need for bone augmentation procedures. This systematic review aims to assess implant survival and implant marginal bone loss among different single-unit narrow implant diameters and between titanium single-unit and titanium-zirconia single-unit narrow implants.

Material and methods: This article was structured according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA®) Included criteria were randomized clinical trials (RCTs) and clinical prospective studies with at least 10 patients, a mean follow-up period of at least 12 months, and assessing single-tooth implants with a diameter of 3.5 mm or less.

Results: Twelve included articles were prospective clinical studies, while 3 articles were randomized controlled clinical studies. There are no significant differences in the comparison between the 2.9-3.0 mm group and the 3.3-3.5 mm group (p=0.933). Both groups had a 99% survival (95% CI, 99.9%-100%). Titanium-zirconia implants presented a mean of marginal bone loss of -0,37 mm (CI, 95%: -0,53 to -0,20) meanwhile, titanium implants had a mean of marginal bone loss of -0,43 mm (CI95%:-0,71 to -0,28).

Conclusions: The findings reveal no significant differences between 2.9-3.3mm and 3.3-3.5mm groups within narrow implants. Both titanium and titanium-zirconia alloys in narrow implants, exhibit comparable high survival rates and minimal marginal bone loss, showcasing their feasibility as a viable treatment alternative in scenarios with limited space or inadequate bone for regular diameter implants.