The influence of mechanical stimulation on osteoclast localization in the mouse maxilla: bone histomorphometry and finite element analysis

Abstract

The mechanism of traumatic bone resorption in the denture-bearing bone has not yet been established with regard to the osteoclastic activity in relation to the mechanical stimulus. The purpose of this study was to clarify whether osteoclast appearance in maxilla depends on the strain intensity, using the murine loading model. The maxillary palate of thirteen-week-old male C57BL/6 mice was subjected to continuous pressure of 2 kPa (low stimulation, n = 4) or 7 kPa (high stimulation, n = 4) for 30 min/day for 7 consecutive days, and the mice were sacrificed after the last loading. The control group underwent the same protocol without load (n = 4). An animal-specific finite element model was constructed based on morphology and characteristics obtained from the micro-CT data and used to calculate the strain intensity of the bone. The bone histomorphometric technique revealed significant reduction of cortical bone volume and significant increase of bone resorption parameters such as osteoclast number in the bone tissue under the loading contact in comparison to the control (p < 0.05). The osteoclasts were observed in the subsurface region adjacent to the loading contact and the peripheral region of the marrow space in the intracortical region of the cortical bone in the mouse maxilla in both stimulation groups. An average of more than 90 % of the osteoclasts was observed in the areas with strain intensity higher than 85.0μ strain for the high stimulation group. The result suggests that the osteoclastic resorption is location-dependent and is also sensitive to the local strain intensity.

Effects of occlusal forces on the peri‐implant‐bone interface stability

“…Studies in mice showed an increased number of osteoclasts and higher resorption rates in continuous overloaded palatal bone. Therefore, the authors concluded that the osteoclastic resorption is location‐dependent and is sensitive to the local strain intensity …”

Determination of vibration acceleration mechanism and vibration load application duration from a non-biological perspective: Orthodontic Acceleration

“…Since the properties of bone material are constantly changing with its metabolism, we can only observe the macroscopic results of the alveolar bone reconstruction process, so this work also addresses the material properties in a macroscopic sense. Depending on the location of load application which also affects osteoclast resorption (Fujiki K, 2013), the direction of vibratory load application is divided into the lingual, lip, and gingival orientation in this work, as shown in Figure 2b.…”

“…The low-intensity mechanical signal formed by the stimulated bone depends on the frequency of the mechanical signal rather than the strain amplitude (Judex S, 2018;Shipley T, 2019). In addition to accelerating orthodontic teeth movement (Chen Y, 2020), vibrations can also affect osteoclast activity in the maxilla and is sensitive to the intensity of strain localized in that zone (Fujiki K, 2013). There is an obvious lack of data on the changes in alveolar bone parameters during orthodontic acceleration in most existing research studies using biological models.…”

Potential for estimation of Young's modulus based on computed tomography numbers in bone: A validation study using a nano-indentation test on murine maxilla

“…After gently removing the soft tissue surrounding the bone, the maxilla of each mouse was harvested. The dissected maxillae were sectioned parallel to the frontal plane for histological analysis, as described previously [21,22] (Figure 1). Each sample was sectioned with a low-speed diamond saw (BS-3000; EXAKT Apparatebau GmbH, Norderstedt, Germany) at a thickness of approximately 1-2 mm at a position 2-3 mm behind the tip of the nose.…”

“…ROI-1 was defined at the cortical region of the palate, close to the median, approximately 500 µm away from the basis of the incisal tooth (Fujiki et al 2013, Suzuki et al 2016), while ROI-2 was also set at the cortical bone structure, approximately 500 µm outside of the ROI-1. Each ROI comprised an area of 0.7 × 0.7 mm.…”