Tooth movement out of the bony wall using augmented corticotomy with nonautogenous graft materials for bone regeneration

Abstract

This prospective randomized split-mouth study was performed to compare the effects of augmented corticotomy with those of different nonautogenous bone graft materials combined with orthodontic tooth movement in dogs. Decortication was performed on the buccal bone surface of 6 male beagle dogs that were randomly assigned to receive grafts of deproteinized bovine bone mineral, irradiated cortical bone, or synthetic bone. Immediate orthodontic force was applied to the second and third premolars for buccal tipping for 6 weeks. The pocket depth and width of keratinized tissue (WKT) were measured. Histologic and histomorphometric analyses were performed. The probing depth, WKT, and ratio of the area of new bone to that of total bone on the buccal side were not significantly different between groups. All groups had considerable new bone formation on the pressure side. New bone formation on the buccal side and buccal plate formation in the coronal direction along the root surfaces were induced by the bone-derived and PDL-derived mesenchymal matrix, respectively. The angular change between groups was significantly different (P < 0.001). Augmented corticotomy using nonautogenous graft materials facilitated tooth movement without fenestrations and accelerated new bone formation on the pressure side.

Figures

Figure 1

Surgical procedure. Full-thickness flap elevation and corticotomy were performed on the buccal side (a). Deproteinized bovine bone mineral (DBBM) particles (b), irradiated cortical bone (ICB) particles (c), and micromacroporous biphasic calcium phosphate (SB: MBCP+) particles (d) were grafted. Primary closure was obtained, and activation of P2 and P3 for buccal tipping was started with a closed coil spring (200 g) ((e) and (f)).

Figure 2

Methods of measurements. (a)–(d) Maxilla, buccal tipping angle (red dotted line) and buccal bone wall area. (e)–(h) Mandible, buccal tipping angle (red dotted line) and buccal bone wall area. Yellow arrow indicates PDL-derived mesenchymal matrix, white arrow indicates buccal mesenchymal matrix, and red arrow indicates bone-derived mesenchymal matrix. (b), (f) Yellow arrow and stars indicate PDL-derived mesenchymal matrix. New bone formation was observed around grafted particles that were embedded in PDL-derived mesenchymal matrix. (c), (g) White arrow and stars indicate the buccal mesenchymal matrix, which plays the role of thick periosteum. (d), (h) Red arrow and stars indicate bone-derived mesenchymal matrix that appears to be loose connective tissue. Masson's trichrome stain. Original magnification for (a) and (e): ×12.5; for (b), (c), (d), (f), (g), (h): ×100.

Figure 3

(a) Buccal tipping angle (°). (b) New bone area (NB, %). *P < 0.05.

Figure 4

Microphotograph of a buccopalatal section from the maxilla. (a) Deproteinized bovine bone mineral (DBBM) graft. (b) Higher magnification of (a). Red stars indicate DBBM particles that were embedded in and bridged with newly formed bone within the bone-derived mesenchymal matrix. (c) Higher magnification of (b). Active aggregated osteoblasts were observed to form new bone matrix. (d) Irradiated cortical bone (ICB) graft. Most of the grafted ICB particles were resorbed. Grafted ICB particles were embedded in bone-derived mesenchymal matrix, encircled by a newly formed bone wall (yellow arrows). Newly formed bone walls in the mesenchymal matrix appeared to represent buccal bone expansion or bursting. (e) Higher magnification of (d). Grafted particles were bridged with newly formed bone. (f) Higher magnification of (e). Active osteoclasts and osteoblasts are shown. Grafted ICB particles were still resorbed by osteoclasts within the bone-derived mesenchymal matrix. (g) Micromacroporous biphasic calcium phosphate (SB; MBCP+) graft. Some of the grafted SB particles were embedded in the newly formed buccal bone wall and faced the PDL-derived mesenchymal matrix. (h) Higher magnification of (g). Grafted SB particles were resorbed by osteoclasts in the PDL-derived mesenchymal matrix and embedded in newly formed buccal bone. Small capillaries were abundant around the grafted particles (black star). (i) Higher magnification of (h). The surface of grafted SB particles was covered with newly formed bone and resorbed by osteoclasts in the process of remodeling. Masson's trichrome stain. Original magnification for (a), (d), and (g): ×12.5; for (b), (e), and (h): ×100; for (c), (f), and (i): ×400.

Figure 5

Photomicrograph of a buccolingual section from the mandible. (a) Deproteinized bovine bone mineral (DBBM) graft. (b) Higher magnification of (a). DBBM particles (red star) were embedded in and bridged with newly formed bone within the bone-derived mesenchymal matrix. Resorption by osteoclasts at the buccal side and new bone formation at the inner side by osteoblasts were observed simultaneously. (c) Higher magnification of (b). New bone formation on the surface of the grafted DBBM particles (red star) and active osteoblasts were observed. (d) Irradiated cortical bone (ICB) graft. Most grafted ICB particles were resorbed. Grafted ICB particles were embedded in bone-derived mesenchymal matrix, encircled by a newly formed bone wall. (e) Higher magnification of (d). Grafted ICB particles (yellow star) were still resorbed by osteoclasts within the bone-derived mesenchymal matrix, and newly formed bone was bridged with and formed in the grafted particle. (f) Higher magnification of (e). Active osteoblasts forming new bone were observed inside the grafted ICB particles. (g) Micromacroporous biphasic calcium phosphate (SB; MBCP+) graft. Most of the grafted SB particles were embedded in the newly formed bone-derived mesenchymal matrix that formed buccal bone. The thickness of the newly formed bone wall was outstanding. (h) Higher magnification of (g). Grafted SB particles (black star) were embedded in and bridged with newly formed buccal bone. (i) Higher magnification of (h). Active new bone-forming osteoblasts were observed at the outer surface of the buccal bone wall. Masson's trichrome stain. Original magnification for (a), (d), and (g): ×12.5; for (b), (e), and (h): ×100; for (c), (f), and (i); ×400.