Changes in stability and marginal bone level around implants with hydrophilic and hydrophobic surfaces for posterior tooth replacement: A 1-year randomized clinical trial

Abstract

Aim

This two-group parallel, double-blind, randomized clinical trial compared the 1-year changes in longitudinal stability and marginal bone level (MBL) between implants with hydrophilic (HPL) and hydrophobic (HPB) surfaces.

Materials and Methods

Patients with single posterior edentulous spaces were randomly assigned to two groups (HPL and HPB), and implants were inserted using a guided protocol. Screw-retained provisional and metal-ceramic crowns were provided per the manufacturer's loading protocol. The implant stability quotient (ISQ) was measured immediately and after 15, 30, 45 (HPL loading), 60, 90 (HPB loading) days, and then at 15, 30, 45 days, 6 and 12 months after final loading. Bone level was assessed at baseline, and 2-weeks, 6 and 12 months after loading. Generalized Estimating Equations regression was used for data analysis due to dependent longitudinal measurements and pooled data from multiple implants within patients.

Results

Thirty-two patients received 48 implants (HPL=22; HPB=26). The initial Mean ISQ was 65.4±10.7Ncm (HPL=63.3±10.4; HPB=67.4±10.7; p=0.191). There was an increase in ISQ in the short-term post-insertion period from T0 to T3 (45 days) in both groups, and no significant changes occurred until T2 (30 days). ISQ comparisons between the final restoration and 1-year follow-up showed significant improvement for HPB (p=0.007) and HPL (p=0.045) groups. The final regression model confirmed that ISQ measures were affected by the progression of time after insertion until 60 days (p=0.003), 180 days (p<0.001), and 1-year (p<0.001). HPB group showed higher ISQ at any time (p=0.048).

Conclusion

There was a progressive increase in secondary stability up to approximately 60 days, and the hydrophobic group showed slightly higher ISQ measurements at all time points.

Clinical significance

This study provides evidence on the comparative longitudinal performance of implants with hydrophilic and hydrophobic surfaces in the posterior region, showing a progressive increase in the secondary stability up to approximately 60 days in both groups. The hydrophobic surface group showed slightly higher ISQ measurements at all time points, however, with no relevant clinical impact on survival and marginal bone changes.