Relação entre proporção de osso cortical e análise de textura trabecular em tomografias computadorizadas com estabilidade e perda óssea de implantes curtos

Abstract

Dental implants have been broadly used in oral rehabilitation. Short implants are a valid alternative in cases where bone quantity prevents the use of longer implants, which would require bone reconstruction, making the treatment more invasive, increasing the risk of biological complications, cost and duration of treatment. In addition to the bone quantity, the quality of the potential receptor site is an important factor to be considered. The present prospective clinical-radiographic cohort study aimed to evaluate, in manuscript 1, the stability of short implants and the proportion of cortical bone, and in manuscript 2, the texture characteristics of trabecular bone as predictive factors of marginal bone loss in single-stand short implants in the posterior region of maxilla and mandible. Methods: A total of 46 Standard Plus Regular Neck SLActive® (Straumann Dental Implant System®, Waldenburg, Switzerland) implants 6-mm long and 4.1-mm in diameter were installed in 20 patients, who were clinically and radiographically evaluated immediately after implant installation, and 12, 24, 36, 48 months after the prosthesis. In this study, preoperative computed tomography scans were evaluated for bone quality analysis. In manuscript 1, the proportion of cortical bone, primary and secondary stability were analyzed as predictors of marginal bone loss. In manuscript 2, the characteristics of trabecular bone were analyzed through the Gray Level Co-Occurrence Matrix (GLCM) analysis method as predictors of bone loss. The results of this study were based on the three periods of time: baseline - 12 months (P1), 12 - 48 months (P2) and baseline - 48 months (P3) . Results: In manuscript 1, the proportion of cortical bone in the coronal plane (PROPc) showed a significant association with bone loss (MBL) (P <0.023). An increase of 0.1 in PROPc estimated a lower bone loss at -0.11 mm for MBL (95% CI: -0.21, -0.02). Time was significantly associated with MBL (P <0.001). A mean bone loss was estimated at 0.09 mm / year (95% CI: 0.05, 0.14). For the implant stability model, only time had a significant effect on MBL, estimating an average bone loss of 0.10 mm for a 12-month increase (P <0.001, 95% CI: 0.05, 0.15). In manuscript 2, the trabecular bone texture features showed a significant association with MBL, depending on the period of analysis. ASM showed a significant association with MBL for P2 (P = 0.0479) and P3 (P = 0.0497), but not for the first year of loading. Correlation (P = 0.0152) and IDM (P = 0.0115) showed association for P1. Entropy presented association with MBL for all time periods analyzed: P1 (P = 0.0305), P2 (P = 0.0192) and P3 (P = 0.0099). The univariate regression model showed that, for an increase of 0.1 in ASM, a lower bone loss of 16.67 mm would be estimated for P2 (95% CI: -33.36, 0.01) and 14.74 mm for P3 (95% CI: 7.58, 29.62). For an increase of 0.1 in Correlation, a higher bone loss of 0.9 mm was estimated for P1 (95% CI: 0.17, 1.61). For an increase of 0.1 in Entropy, a higher bone loss of 0.2 mm was estimated for P1 (95% CI: 0.02, 0.45), 0.3 mm for P2 (95% CI: 0.04, 0.51). and 0.3 mm for P3 (95% CI: 0.06, 0.47). For an increase of 0.1 in the IDM, a lower bone loss of 4.79 mm was estimated for P1 (95% CI: -8.50, -1.07). Time had a significant effect on MBL, depending on the period analyzed. Conclusions: The macro and microstructural characteristics of the bone tissue impact on the stability of bone levels of single-stand short implants in the posterior region over time. The proportion of cortical bone and time were predictors of peri-implant marginal bone loss in this sample. An increase in the proportion of cortical bone appears to be a protective factor for bone loss. Primary and secondary stability did not affect marginal bone loss around implants. Trabecular bone texture features were predictors of marginal bone loss of short implants in the posterior region of the maxilla and mandible.