Blood clot stability and bone formation following maxillary sinus membrane elevation and space maintenance by means of immediate implant placement in humans. A computed tomography study.

OBJECTIVE

The present controlled clinical pilot study proposed to assess blood clot contraction and bone neo-formation following maxillary sinus lift (MSL) with immediate implant placement without using grafts using cone beam tomography exams.

MATERIALS AND

METHODS

Ten implants were placed in ten patients with a residual bone crest height ≥4 and ≤ 7 mm, in maxillary premolars or 1st or 2nd molars regions, using MSL and immediate implant placement without grafts, by means of the lateral window approach. A resorbable membrane (Bio-Gide®, Geistlich, USA) was used to close the window. Computed tomography images were taken after 15 (T1) and 180 (T2) days to assess the rate of blood clot contraction and bone neo-formation. The images were analysed by OsirixMD software. The Shapiro Wilk test was used to verify the normality hypothesis and the data were submitted to Student's paired t-test.

RESULTS

The mean of bone clot height in mesial, apical and distal area referred to implant, presented 4.77 mm, 0.77 mm and 5.30 mm respectively. The mean measurements of new bone formation presented 2.95 mm, 0.44 mm and 3.45 mm. The height contraction (coagulum/new bone formation), between T1 and T2, presented 38%, 43% and 35% respectively, with a significant statistical value p < 0.05. The volume measurements at T1 presented a mean volume of 0.90 cm3 sd ± 0.60 cm3 and at T2 a mean volume of 0.75 cm3 sd ± 0.62 cm3, with a significant volume contraction between T1 and T2, p < 0.005. The mean blood clot contraction was 16.52% ± 8.60%.

CONCLUSION

The present study demonstrates consistent bone formation around all assessed implants, although with significant contraction of the blood clot. The need for longitudinal studies to establish a long-term prognosis in different modalities of prosthetic rehabilitation of those implants is strongly suggested.