Does Systemic Bifidobacterium longum Improve Bone Formation After Maxillary Sinus Floor Elevation Under Osteoporotic Conditions? An Experimental Rabbit Study.

BACKGROUND

Osteoporosis impairs bone microarchitecture and reduces the success of preprosthetic alveolar augmentation. Whether systemic probiotics improve bone formation after maxillary sinus floor elevation (MSFE) under osteoporotic conditions is unknown.

PURPOSE: To measure and compare new bone formation after MSFE in rabbits with and without induced osteoporosis and with and without systemic Bifidobacterium longum supplementation.

STUDY DESIGN, SETTING, AND SAMPLE: Prospective experimental animal study at a university research center (Kayseri, Türkiye). Adult female New Zealand white rabbits underwent bilateral MSFE with deproteinized bovine bone graft; those with sinus pathology or systemic illness were excluded.

PREDICTOR VARIABLES: Osteoporosis induction status (yes/no) and systemic B longum supplementation (yes/no), crossed to produce 4 groups (n = 6 each).

MAIN OUTCOME VARIABLES: Primary - micro-computed tomography trabecular microarchitecture at 8 weeks: trabecular number, trabecular separation, bone surface density, and bone mineral density. Secondary - qualitative histological bone maturity.

COVARIATES: None.

ANALYSES: According to distribution, four-group comparisons used one-way analysis of variance with the Tukey honestly significant difference test or the Kruskal-Wallis test with the Dunn-Bonferroni test. All pairwise comparisons were corrected for multiple comparisons; statistical significance was set at P ≤ .05.

RESULTS

Twenty-four rabbits (n = 6 per group) completed the study. Under osteoporotic conditions, animals receiving B longum had statistically significantly higher trabecular number [3.83 (0.12) versus 3.19 (0.32) mm-1; P = .011], bone surface density [16.22 (0.36) versus 14.18 (0.92) mm-1; P = .005] and lower trabecular separation [202 (4) versus 235 (24) μm; P = .009] than those not receiving probiotics. Bone mineral density and closed porosity percentage did not differ statistically significantly (P ≥ .5). No micro-computed tomography parameter differed between the osteoporosis + probiotic and control groups (all P ≥ .1). Histologically, the osteoporosis + probiotic group showed more mature bone than the osteoporosis-only group.

CONCLUSIONS AND RELEVANCE: Within the limits of this rabbit model, systemic B longum improved trabecular microarchitecture after MSFE under osteoporotic conditions, approaching healthy control values. Probiotics may be a low-morbidity adjunct in osteoporotic patients undergoing preimplant augmentation; clinical translation requires further study.