Osteogenic effects of bioabsorbable magnesium implant in rat mandibles and in vitro

Abstract

Background Bone augmentation or grafting is often required for placement of dental implants or surgical reconstruction of bony defects. Bioabsorbable magnesium implant was shown to promote osteogenesis in long bones. The objectives of this study were to determine osteogenic effects of pure magnesium (Mg) in rat mandible and underlying mechanisms. Methods Pure Mg was implanted in sockets after rat mandibular incisors were extracted. Titanium (Ti) was used as control. Systemic effects were determined by serum Mg level and histologic analyses of liver and kidney. Local Mg concentration was measured by microscopy‐energy‐dispersive spectroscopy (SEM‐EDS). Alveolar bone was analyzed by micro‐computed tomography (micro‐CT) and histology. Osteogenic effects of 0.8 to 20 mM magnesium chloride (MgCl2) on periosteum‐derived cells (PDCs) were evaluated by proliferation, alizarin red staining and quantitative RT‐PCR assays. Results Systemic effects were similar in Mg and Ti groups. Higher local Mg concentration was detected in Mg group (P < 0.05). Micro‐CT showed higher alveolar bone volume (2‐ and 6‐weeks post‐operation) and denser cancellous bone (2 weeks post‐operation) in Mg group, with significant amount of new subperiosteal bone formation on lateral alveolar bone surfaces by H&E staining. In PDC culture, proliferation rates, osteogenic gene expression for runt related transcription factor 2 (Runx2), bone sialoprotein (Bsp) and osteocalcin (Ocn), as well as calcium nodule formation rose significantly in 5, 10, and 20 mM MgCl2 groups. Conclusions Rapid osteogenesis (especially subperiosteal) is induced by pure Mg in rat mandibular alveolar bone. Osteogenic capacity of PDCs is enhanced by higher Mg ion concentrations in vitro.

Biodegradable metals for bone defect repair: A systematic review and meta-analysis based on animal studies

“…Seven studies were excluded for failing to report on any of the six outcome measures for the systematic review. After excluding six conference abstracts, five duplicate studies and 26 studies with fracture animal model as research objective, 30 animal studies of bone defect repair with biodegradable metals were included, with 25 in English [ [55] , [56] , [57] , [58] , [59] , [60] , [61] , [62] , [63] , [64] , [65] , [66] , [67] , [68] , [69] , [70] , [71] , [72] , [73] , [74] , [75] , [76] , [77] , [78] , [79] ] and five in Chinese [ [80] , [81] , [82] , [83] , [84] ] ( Fig. 1 ).…”

“…After rigorous screening, animal studies of bone defect repair with the following two kinds of biodegradable metals were included, pure magnesium [ 62 , [70] , [71] , [72] , 76 ] and magnesium alloy [ [55] , [56] , [57] , [58] , [59] , [60] , [61] , [63] , [64] , [65] , [66] , [67] , [68] , [69] , [71] , [72] , [73] , 75 , 77 , 78 , [80] , [81] , [82] , [83] , [84] ], and pure Zn [ 74 ] and Zn alloys [ 79 ]. The 30 included studies consisted of 20 randomized controlled studies [ 55 , [58] , [59] , [60] , [63] , [64] , [65] , [66] , [67] , 71 , [74] , [75] , [76] , [77] , [78] , [80] , [81] , [82] , [83] , [84] ] and ten controlled studies [ 56 , 57 , 61 , 62 , [68] , [69] , [70] , 72 , 73 , 79 ]. The animal models in the included studies were rabbits [ 55 ...…”

“…The 30 included studies consisted of 20 randomized controlled studies [ 55 , [58] , [59] , [60] , [63] , [64] , [65] , [66] , [67] , 71 , [74] , [75] , [76] , [77] , [78] , [80] , [81] , [82] , [83] , [84] ] and ten controlled studies [ 56 , 57 , 61 , 62 , [68] , [69] , [70] , 72 , 73 , 79 ]. The animal models in the included studies were rabbits [ 55 , 57 , 58 , 60 , 61 , 63 , 65 , 70 , 72 , 73 , 75 , 80 , 82 , 84 ], rats [ 56 , 59 , 64 , 69 , 71 , 74 , 76 , 79 , 81 , 83 ], mice [ 62 ], sheep [ 66 , 68 ], beagles [ 77 ], guinea pigs [ 78 ] and pigs [ 67 ]. Ages were mostly between five weeks [ 56 , 64 ] and 12 months [ 77 ] and weights between 2.0 kg [ 61 ,…”

“…The sample sizes were between three [ 72 ] and 56 [ 70 ]. Bone defect models included tibial defect [ 55 , 57 , 59 , 60 , 63 , 69 , 70 ] (23%), femoral defect [ 56 , 61 , 64 , 70 , 71 , 73 , 78 , [81] , [82] , [83] ] (33%), mandibular defect [ 58 , 65 , 67 , 72 , 76 , 80 , 82 ] (23%), femoral condyle defect [ 68 , 79 ] (6%), skull defect [ 62 , 74 , 75 ] (10%), ulna defect [ 84 ] (3%) and orbital defect [ 77 ] (3%). CSD models included skull defect model [ 62 , 74 ] (6%) and ulna defect model [ 84 ] (3%) (see Fig.…”

“… F 12 Mos. 5–7 kg Rabbit mandible Ø: 0.85 mm U 6 Weeks N He, Wei 2020 [ 76 ] China Ran Rats/SD 18/18 F 3 Mos. / alveolar bone Ø: 1.4 mm U 6 Weeks N Magnesium alloy Erdmann, N 2010 [ 55 ] Germany Ran NZW 24/16 F Adult 3.81 ± 0.84 kg Both tibiae Ø: 3.5 mm U 8 Weeks N Celarek, A 2012 [ 56 ] Austria Ctrl Rats/SD / M 5 weeks 140–160 g Each distal femur Ø: 1.5 mm U 6 Mos.…”