Five-year survival of short and ultra-short implants placed in the posterior maxilla and mandible

PBIE1 ePOSTER CLINICAL RESEARCH – PERI-IMPLANT BIOLOGY

Background: Peri-implant bone loss is a frequently used primary outcome in reporting short and ultra-short implant survival. A potential reason is the fact that whereas minimum bone loss may be negligible in regular sized implants, it may present a risk to survival of the final restored system in ultra-short implants.

Aim/Hypothesis: The aim of this 5-year retrospective study was to assess survival rate and peri-implant marginal bone loss of short and ultra-short locking-taper implants, placed in the maxillary and mandibular posterior regions and restored with single crowns.

Materials and Methods: 148 patients received 337 short (8 mm and 6 mm-length) and ultra-short (5 mm-length) locking-taper implants between February 2007 and July 2015. Clinical and radiographic follow-up examinations were performed at a 5-year recall appointment. Implant survival rate, peri-implant bone levels and soft tissues conditions were evaluated. Significance level was set at 0.05.

Results: Implants positioned were respectively 202 and 135 in the posterior mandible and in the posterior maxilla; 126 implants were 8 mm-length, 118 were 6 mm-length and 93 were 5 mm-length. As one implant failed before loading, from a total of 336 implants restored with single crowns, 218 presented a history of periodontal disease and 118 implants were healthy. After 5 years of loading, overall implant survival rate was 97.03%, without any significant differences between length groups (P = 0.53): 97.62% for 8 mm-length implants, 95.76% for 6 mm-length implants, 97.85% for 5 mm-length implants respectively. Mean DCBL (average bone loss) was 0.89(1.07) mm and mean DF-BIC (average apical shift of the “first bone-to-implant contact point” position) was 0.16(0.65) mm, showing that crestal bone levels remained stable after 5 years. No significant differences were found among length-groups both for DCBL (P = 0.21) and DF-BIC (P = 0.78).

Conclusions and Clinical Implications: Five-year outcomes suggest that short and ultra-short locking-taper implants restored with single crowns can offer a predictable solution in the rehabilitation of the atrophic posterior maxillary and mandibular regions.

Keywords: short implants, ultrashort implants, survival, bone loss, single crown