Rehabilitation of the Atrophic Posterior Maxilla Using Splinted Short Implants or Sinus Augmentation with Standard-Length Implants: A Retrospective Cohort Study

Purpose: To retrospectively compare short implants (6 to 8 mm) (short group) to standard-length implants (≥ 11 mm) inserted in combination with a lateral sinus elevation procedure (sinus group), supporting partial fixed prostheses in the atrophic posterior maxilla. Materials and Methods: Records of 118 patients treated with fluoride-modified implants in the atrophic posterior maxilla between January 2009 and December 2011 were screened in two private practices. Two to four implants were placed in each patient and loaded after 5 to 6 months with partial fixed prostheses. Patients were followed for at least 3 years after implant placement. Patients were contacted and invited for clinical and radiologic follow-up examinations. Outcome measures were implant failures, complications, soft tissue parameters, and marginal bone levels. Fisher exact and unpaired t tests were used to compare proportions and means at the .05 level of significance. Results: A total of 101 patients attended the examination: 53 (112 implants) in the sinus group and 48 (109 implants) in the short group. The mean observation period was 47.03 ± 7.46 months for the sinus group and 44.18 ± 6.42 months for the short group. Ten surgical complications occurred in nine patients of the sinus group versus only one complication in the short group; the difference was statistically significant (P = .01). Six implants failed in five patients of the sinus group versus two implants in two patients of the short group. At follow-up, mean marginal bone loss was 0.64 ± 0.58 mm in the sinus group vs 0.48 ± 0.5 mm in the short group. No significant difference was observed in terms of implant failures, prosthetic complications, soft tissue parameters, or marginal bone loss between the two groups. Conclusion: Within the limitations of this study, both techniques showed similar medium-term outcomes, but short implants provided advantages in terms of a reduced number of surgical complications. Keywords: anorganic bovine bone, complications, marginal bone loss, maxillary sinus augmentation, short dental implants, survival rate