Evaluation of Short and Regular Implants after Prosthesis Placement in the Mandible: A Nonrandomized Controlled Clinical Trial.

AIM: The aim of this nonrandomized controlled preliminary clinical trial was to compare treatment using short and conventional implants in the posterior region of the mandible after prosthesis installation by means of clinical, resonance frequency, and radiographic analyses. MATERIALS AND METHODS: A total of 10 patients with 40 dental implants already installed were included in this study. Four implants were installed for each subject, in which the length of the implants (short and conventional) was distributed according to the reminiscent alveolar bone in the left and right side of the mandible. All implants received splinted prosthesis after the osseointegration period. Analyses were performed immediately after prosthesis installation (T1), and 3 (T2) and 6 months (T3) after prosthesis placement. RESULTS: The 6-month survival and success rates were 100% for the short and conventional implants. Probing depths (PDs) after 6 months did not show statistical differences between short and conventional implants. All groups showed mean implant stability quotient (ISQ) values above 60 in all periods evaluated, demonstrating great implant stability, and no differences were found between groups at T3. Radiographic measurements showed an increased bone loss for conventional implants compared with short implants in all the three periods evaluated. CONCLUSION: Our findings suggest that treatment of resorbed posterior regions in the mandible with shorter dental implants is as reliable as treatment with conventional implants after 6 months of splinted prosthesis installation. CLINICAL SIGNIFICANCE: Short implants might be considered a predictable treatment alternative to bone augmentation or extensive surgical techniques in regions of restricted vertical bone height in the posterior region of the mandible.

Clinical study on survival rate of short implants placed in the posterior mandibular region: resonance frequency analysis.

OBJECTIVE: Short implants are increasingly used, but there is doubt about their performance being similar to that of regular implants. The aim of this study was to compare the mechanical stability of short implants vs. regular implants placed in the edentulous posterior mandible. MATERIAL AND METHODS: Twenty-three patients received a total of 48 short implants (5 × 5.5 mm and 5 × 7 mm) and 42 regular implants (4 × 10 mm and 4 × 11.5 mm) in the posterior mandible. Patients who received short implants had <10 mm of bone height measured from the bone crest to the outer wall of the mandibular canal. Resonance frequency analysis (RFA) was performed at time intervals T0 (immediately after implant placement), T1 (after 15 days), T2 (after 30 days), T3 (after 60 days), and T4 (after 90 days). RESULTS: The survival rate after 90 days was 87.5% for the short implants and 100% for regular implants (P < 0.05). There was no significant difference between the implants in time intervals T1, T2, T3, and T4. In T0, the RFA values of 5 × 5.5 implants were higher than values of 5 × 7 and 4 × 11.5 implants (P < 0.05). A total of six short implants that were placed in four patients were lost (three of 5 × 5.5 mm and three of 5 × 7 mm). Three lost implants started with high ISQ values, which progressively decreased. The other three lost implants started with a slightly lower ISQ value, which rose and then began to fall. CONCLUSIONS: Survival rate of short implants after 90 days was lower than that of regular implants. However, short implants may be considered a reasonable alternative for rehabilitation of severely resorbed mandibles with reduced height, to avoid performing bone reconstruction before implant placement. Patients need to be aware of the reduced survival rate compared with regular implants before implant placement to avoid disappointments.