Longevity factors for short and extra-short implants: An eight-year retrospective observational clinical study

This study aimed to evaluate implants placed in the mandible and maxilla and analyze the correlation between local and systemic factors that affect the clinical and prosthetic performance of short and extra-short implants.

Implants were analyzed based on 18 factors: Location (anterior or posterior; maxilla or mandible); presence or not of previous grafting; bone quality; prosthesis was/was not installed immediately; type of prosthetic connection (external hexagon or Morse Taper); thread type (trapezoidal, triangular, or hybrid); surface's characteristic; implant length; implant width; prosthesis installation follow-up; type of prosthesis retention (cemented or screw-retained); single prosthesis or splinted to another implant; antagonist occlusion type; presence or absence of intermediary prosthetic component; prosthetic abutment height; distance between intermediaries component; presence or absence of implant bicortilization; and implant insertion torque. Clinical intraoral analysis included dimensions of the occlusal part and the inclination of the cusps (≤15 degrees versus >15 degrees). Possible systemic influences were also evaluated. Patient satisfaction was assessed through a questionnaire. The statistical analysis considered results significant if p<0.05.

This study analyzed 91 dental implants (60 short/extra-short and 31 standard/long) placed in 16 patients, including individuals with diabetes (n=3), smoking (n=1), and parafunctional habits (n=7). Implants were distributed across the maxilla (43.3%) and mandible (56.7%) arches, with one short implant failure (survival rate = 98.3%). The mean peri-implant bone loss was 6.80±13.06 mm² for short/extra-short and 8.19±12.10mm² for standard/long implants. Bone loss was lower in males (3.32±6.03mm²) than in females (7.61±8.55mm²), and implant diameter influenced the osseointe-gration loss area, highlighting relevant biomechanical and risk-related factors. Significantly reduced peri-implant bone loss was observed in implants with abutments >2mm, Morse taper connections, bicorticalization, insertion torque ≤35N, anterior placement, maxillary location, and prior bone grafting (p<0.05 for all). These findings suggest that such variables may positively influence os-seointegration and support the long-term success of short implants.

The use of short- and extra-short implants is a feasible treatment option for mid- and long-term rehabilitation of the full and partial maxillary and mandibular arches.