Clinical Results of Overdentures Retained by Small Diameter Dental Implants

Objectives: This longitudinal clinical study evaluated the peri-implant tissue behavior of the small diameter dental implants (SDI) as mandibular overdenture (MO) retainers.

Methods: Sixty 2.9X10 mm implants were installed in the interforaminal region in 30 patients (20 women and10 men), with an average age of 67.5 years. The implants were loaded after 12 weeks using Equator stud attachments (Neodent). The Plaque index, Calculus index, Gingival index, Probing depth, Bleeding on probing and Implant stability quotient (ISQ) were monitored during osseointegration at baseline, 4, 8 and 12 weeks and post loading at 24, 48 and 60 weeks. Marginal bone loss (MBL) and bone level changes (MBC) were determined using panoramic radiographs at zero and 60 weeks. The data were analyzed with the Wilcoxon paired test, the McNemar test and Spearman correlations.
Results: The cumulative survival rates were 83.3%. The Plaque index oscillated in the first 24 weeks, and decreased from 48 weeks. The Calculus index showed significantly higher values (P <0.05) at week 8 (0.22±0.42). The Gingival index peaked at week 8 and decreased from week 12 onwards. The probing depth decreased gradually over time, but no significant differences were found (P> 0.05), except between week 8 and 12. The ISQ decreased significantly (P = 0.05) during the early healing between 0 and 4 weeks. After the MO loading, the ISQ values increased significantly, reaching values similar to the primary stability (P> 0.05). The marginal bone loss at 60 weeks was similar to initial conditions (P>0.05) and bone level changes were negative (-0.06±0.64). MBC showed a negative correlation with MBL_baseline (R=-0.634, P<0.0001) and a positive correlation with MBL_60weeks (R=0.697, P<0.0001).
Conclusions: The small diameter dental implants showed a stable clinical behavior, indicating that they are an excellent option as MO retainers for edentulous patients, mainly for that ones with mandibular atrophy.