Controlled mechanical early loads improve bone quality and quantity around implants: An in vivo experimental study

Abstract

Objectives: This study aimed to investigate the effects of early loads on bone quality and quantity around implants and to compare the effects of early loads on bone quality and quantity with the effects of conventional loads. Materials and Methods:Grade IV-titanium implants with buttress threads were placed in rat maxillary bone 4 weeks after extraction of first molars. A controlled mechanical load (10 N, 3 Hz, 1800 cycles, 2 days/week) was started via the implants 1 and 3 weeks after implant placement for 2 weeks (early and conventional loads, respectively). Bone quality, defined as distribution of bone cells, types and orientation of collagen fibers, and production of semaphorin3A, its receptor neuropilin-1, and sclerostin, were quantitatively evaluated. Results:Early loads substantially and positively affected bone quality by changing the preferential alignment of collagen fibers with increased production of type I and III collagens, semaphorin3A, and neuropilin-1, increased osteoblast numbers, decreased production of sclerostin, and decreased osteoclast numbers both inside and outside the implant threads, when compared with non-loaded conditions. Conventional loads changed bone quality around implants slightly. Interestingly, early loads had significantly stronger effects on bone quality and quantity based on the evaluation parameters than conventional loads.Conclusions: This is the first report to provide scientific evidence for load initiation time based on both bone quality and quantity around implants. These new findings show that implants with buttress threads transmitted early loads optimally to bone tissue by improving bone quality and quantity inside and outside the implant threads.

Clinical performance of immediately placed and restored progressive-type implants in the esthetic zone: a prospective observational study

“…Even though the underlying evidence is very limited, immediate provisionalization did not seem to have an influence on the survival and success rates [ 3 ]. Apart from a decreased treatment time and avoidance of a removable provisional prosthesis [ 4 ], the mechanical stimulus associated with a controlled immediate restoration may also contribute to the quality and quantity of bone formation [ 5 ]. On the contrary, however, immediate implant placement and the achievement of an adequate primary stability may clearly be challenged by the integrity and morphology of the extraction socket [ 6 ].…”

Effect of intraoral administration of parathyroid hormone on osseous and soft tissue healing around implants in ovariectomized rat maxillae

“…Administration route effects on bone cells inside and outside the areas of the implant threads were then evaluated to verify which routes are superior for bone quality, defined as bone cells including osteoblasts, osteoclasts, and osteocytes in this study (Kuroshima, Kaku, et al., 2017; Suzue et al., 2022). The administration route effects on the number of osteocytes were the same inside and outside the areas of the threads between systemic and intraoral intermittent PTH administrations (Figure 6g and Table 4).…”

“…Bone cells, including osteocytes, osteoblasts, and osteoclasts, were stained, and several histomorphometric parameters were assessed as indicators of the bone quality around the implants (Kuroshima et al., 2015; Kuroshima, Nakano, et al., 2017; Sasaki et al., 2015; Suzue et al., 2022; Uto et al., 2017), although the preferential alignment of collagen and biological apatite was also included for evaluation of bone quality (Nakano et al., 2002). All sections were viewed and photomicrographed using a light microscope (Axio Scope A1; Carl Zeiss Meditec, Inc., Jena, Germany).…”

“…The false discovery rate was used to correct for multiple testing. Significance was determined with a p ‐value and q ‐value < .05, as in our previous animal study (Suzue et al., 2022). All statistical analyses were conducted with Systat 13 (Systat Software).…”

“…In 2000, the National Institutes of Health (NIH) proposed that investigating bone quality, as well as BMD, is absolutely necessary for the determination of bone strength (NIH Consensus Development Panel on Osteoporosis Prevention, 2001). According to our previous investigations, bone cells, collagen fibers, and biological apatite have been proven to potentially become determinant factors of bone quality (Kuroshima et al., 2015; Kuroshima, Nakano, et al., 2017; Sasaki et al., 2015; Suzue et al., 2022; Uto et al., 2017). Our previous study demonstrated that subcutaneous intermittent PTH administration significantly increased bone volume and BMD, in addition to improved bone quality around implants placed into rat tibiae (Uchida et al., 2020).…”