In vitro digital image correlation analysis of the strain transferred by screw-retained fixed partial dentures supported by short and conventional implants.

Purpose: This study used digital image correlation (DIC) to evaluate the strain transferred by splinted and non-splinted screw-retained fixed partial dentures (FPDs) supported by short and conventional implants. Material and

Methods: Four polyurethane models were fabricated to simulate half of the mandibular arch with acrylic resin replicas of the first premolar. Short (5 mm) and/or conventional (11 mm) implants replaced the second premolar and the first and second molars. Groups were: G1, two conventional (second premolar and first molar) and one short (second molar) implant; G2, one conventional (second premolar) and two short (first and second molar) implants; G3, three short implants; and G4, three conventional implants. Splinted (S) and non-splinted (NS) FPDs were screwed to the implant abutments. Occlusal load and a single point load on the second premolar, both of 250 N, were applied. Strain in the horizontal direction (Ɛxx) was calculated and compared using the DIC software.

Results: Splinted crowns presented the highest strain magnitudes of all tested groups (p < 0.05). The strain was concentrated near the short implants and presented a higher magnitude compared to conventional implants, especially in G2S (-560.13 μS), G3S (-372.97 μS), and G4S (-356.67 μS).

Conclusions: Splinted crowns presented a higher strain concentration around the implants, particularly near the implant replacing the first molar. A combination of short and conventional implants seems to be a viable alternative for the rehabilitation of the posterior edentulous mandible with reduced bone height.