ECTS Abstracts (2015) 1 P291

Residual Ridge Resorption of the Human Mandible: a Histological and Micro-CT Analysis

Hannah Dekker, Elizabeth Bloemema, Chris Ten Bruggenkate, Bert Schulten & Nathalie Bravenboer

VU University Medical Center, Amsterdam, The Netherlands.

Following tooth loss, residual ridge resorption (RRR) commences. This is a chronic, progressive, irreversible and cumulative process resulting in the decrease of denture bearing area, compromising prosthodontic rehabilitation with complete dentures. Although numerous causative factors have been mentioned, little is known about the changes in the bone on a cellular level. Therefore, we aimed to investigate the relationship between clinical parameters such as mandibular height (MH) and duration of the edentulous state (DE) with bone histology and micro-CT in mandibular bone of edentulous patients. Twenty-seven patients requiring dental implants for mandibular overdentures, were included, and screened for bone metabolism disorders and DE and MH were registered. During implant surgery bone biopsies were harvested from the mandible. Bone mineral density (BMD) and BV/TV were determined by micro-CT (Scanco medical). Standardised histomorphometry was applied on Goldner and TRAP stained bone tissue sections(NIS elements, Nikon) on cortical and trabecular bone separately. Student’s t-test and Spearman correlations were calculated using GraphPad software. DE is negatively correlated with MH (p=0,0135, R=-0,5297 CI -0,7877 to -0,1135). In trabecular bone, BMD was strongly associated with MH (p<0,0001, R=-0,738 CI: -0,890 to -0,438) but not with DE (p=0,142, R=0,332, CI=-0,130 to 0,675). Bone mass indices (BMD, BV/TV) as well as bone formation indices (OS/BS, OV/BV) were not different between men and women while osteoclast number (NOcl/BS) was significantly higher in women compared with men (p=0.035).Only in women, a significant correlation between DE and osteoclast number was observed (p=0,0153, R=0,787). In edentulous patients mandibular height is decreasing in time, but only the mandibular height is associated with trabecular BMD. Differences between men and women are observed for osteoclast number, indicating that in edentulous women bone resorption more strongly increases in time compared to edentulous men, possibly resulting in more bone loss.

Disclosure: The authors declared no competing interests.

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