Histomorphometric evaluation of different graft associations for maxillary sinus elevation in wide antral cavities: a randomized controlled clinical trial.

OBJECTIVES: Pneumatization of the maxillary sinus can make it difficult, if not impossible, to install osseointegrated implants, and undertake their eventual functional rehabilitation, which may ultimately require regenerative techniques to achieve. This randomized controlled study proposed conducting a histological evaluation of the behavior of different graft materials in wide maxillary sinuses, at a height of 8 to 10 mm from the alveolar ridge, combined with bone remnants less than 3mm. MATERIALS AND METHODS: Thirty-six patients underwent a sinus elevation procedure through the lateral window. The sinuses were randomly filled with the following materials (n=12/group): group 1, xenogenic bone + autogenous bone (ratio 70:30, respectively); group 2, xenogenic bone + L-PRF; and group 3, xenogenic bone. At 8 months, bone biopsies of engrafted sites were harvested and analyzed histomorphometrically in order to quantify newly formed bone tissue. RESULTS: The results showed a greater area of newly formed bone for G1, averaging 2678.37 (1116.40) µm2, compared with G2 at 984.87 (784.27) µm2, and G3 at 480.66 (384.76) µm2 (p < 0.05). Additionally, fewer xenogenic bone particles and a large amount of connective tissue were observed in G2. CONCLUSIONS: In maxillary sinuses with large antral cavities, autogenous bone combined with xenogenic bone seems to demonstrate better graft remodeling and improve bone formation, compared with the addition of L-PRF. CLINICAL RELEVANCE: L-PRF produces few advantages regarding new bone formation in the wide maxillary sinuses. TRIAL REGISTRATION: Brazilian Clinical Trials Registry (REBEC) number RBR-2pbbrvg.

In Vitro Microbiological Analysis of Bacterial Seal in Hybrid Zirconia Abutment Tapered Connection.

PURPOSE: The aim of this study was to evaluate the bacterial seal at the implant-hybrid zirconia abutment interface and Morse taper-type connections through in vitro microbiological analysis. MATERIALS AND METHODS: Sixteen implants and their respective abutments were divided into 3 groups: test (10 sets), positive control (3 sets), and negative control (3 sets). In the test group, 10 implants were contaminated with Escherichia coli using a sterile inoculating loop to the inner portion of the implants, followed by torque application to the abutment (30 N·cm). The positive controls were also contaminated, but no torque was applied to the abutment screw. The negative control consisted of uncontaminated sets. All specimens were immersed in test tubes containing 5 mL brain heart infusion (BHI) broth, maintained in a microbiological incubator for 14 days at 37°C under aerobic conditions, and monitored every 24 hours for evidence of bacterial growth. RESULTS: During the 14 days of incubation, no significant increase in the number of cloudy culture media was observed in the test group (P = 0.448). No significant difference in broth turbidity ratio was observed (P > 0.05). CONCLUSION: Hybrid zirconia abutments can create an effective seal at the tapered abutment-implant interface with a 30-N·cm installation torque.