Radiological Study on the Evolution of the Biomaterial's Image (Shape, Density, Vertical Dimensions) after the Lateral Sinus Lift

The aim of this study is to evaluate the long-term changes of sinus lift material. Materials and methods: We included a total number of 35 patients (20 men and 15 women), between 32 and 80 years old, evaluated on a timeframe of up to 11.6 years. Diverse biomaterials were used (allograft, xenograft, alloplastic, combinations of them), with autologous bone in some cases. Results: The appearance of the top plane of the bone over time took a large dome shape (36% of cases), a linear shape (32% of cases), an irregular shape (23% of cases), or had micro domes above the implants (7%). No significant differences were found between the groups regarding age. The radiological density of the biomaterial tended to equalize that of the native bone. The final vertical dimensions seemed to be independent of the initial native bone height but seemed to be correlated with the amount of applied biomaterial. For the study group, the biomaterial contracted on average by 10% for the maximum height (H max) and 20% for the minimum height (H min), which can explain the tendency of the upper border of the biomaterial to curve. The annual H max contraction ranged from -0.09 to +0.18 with a mean value of 2.67% (SD = 0.04, CI: [0.011, 0.041]). The median value was 1.8%. The annual H min contraction ranged from -0.24 to +0.24, with a mean value of 4.33% (SD = 0.07, CI: [0.021, 0.065]). The median value was 3.59%. There were no statistically significant gender differences (Mann-Whitney U, p = 0.483, p = 0.642). The additional application of biomaterial together with the implants seemed to have a beneficial effect on the final vertical dimension of the bio-transformed material.