Creation of Bone and Soft Tissue in Postmaxillectomy Patients Using Curvilinear Transport Distraction Osteogenesis

[Nerve growth factor combined with dental pulp stem cells promotes peri-implant osseointegration in rats]

OBJECTIVE

To observe the effect of nerve growth factor (NGF) combined with dental pulp stem cells (DPSCs) on periimplant osseointegration in rats and explore the underlying mechanism.

METHODS

Cultured DPSCs were treated with NFG or with NFG plus the TrkA antagonist K252a, and after osteogenic induction, the formation of calcium nodules was observed and the expressions of RUNX2 and osteocalcin (OCN) were detected with Western blotting. SD rat models with femoral implantation of dental implants were established and divided into control, DPSCs, DPSCs+NGF, DPSCs+K252a, and DPSCs+ NGF+K252a groups, and in all but the control group, DPSCs were injected locally before placement of the implants (n=8); NGF, K252a and their combination were injected intraperitoneally on a daily basis for 4 weeks. All the rats underwent micro-CT, and the peri-implant bone tissues were collected for HE staining and detection of RUNX2 and OCN expressions using Western blotting.

RESULTS

In cultured DPSCs, the number of calcium nodules and the expression levels of RUNX2 and OCN were significantly higher in NGF group than in the control group (P < 0.05), and were significantly lower in NGF+K252a group than in NGF group (P < 0.05). In the rat models, the BMD, TB. Th, TB. N and expressions of RUNX2 and OCN in the peri-implant bone tissues were significantly higher in DPSCs group and DPSCs+NGF group than in the control group (P < 0.05), significantly higher in DPSCs+NGF group than in DPSCs group (P < 0.05), comparable between DPSCs+K252a group and DPSCs group (P> 0.05), and significantly lower in DPSCs+NGF+K252a group than in DPSCs+NGF group (P < 0.05).

CONCLUSION

NGF combined with DPSCs can promote osseointegration in the peri-implant tissues in rats possibly due to a TrkA-mediated effect of NGF for promoting osteogenic differentiation of the DPSCs.

Revascularized Fibula Free Flap Reconstruction and Curvilinear Transport Distraction Osteogenesis in Closure of Large Postmaxillectomy Defects: A New Gold Standard?

Introduction:

The revascularized fibula free flap (RFFF) is the most popular method of postmaxillectomy reconstruction. This article proves that the use of curvilinear transport distraction osteogenesis (CTDO) is an efficacious way in closing large defects in the maxilla and a superior alternative to the RFFF.

Methods and Materials:

In a prospective cohort study of six postmaxillectomy patients, CTDO was applied and the new bone (regenerate) was compared with the parent bone from which it had been regenerated. These results were compared with a retrospective group of six participants of similar age and sex who had undergone RFFF reconstruction as an external control. Clinical measurements taken at the depth of the alveolar vestibule were recorded at three different exact points juxtaposed, namely (A) lateral incisor, (B) first premolar, and (C) first molar. These areas of interest were similar to those chosen on the CT scans. Impressions were taken from all the patients and stone casts were made. The width of the alveolar bone was computed based on the measurements made from the stone casts. The stone casts were then used to calculate the width and depth of the soft tissue and bone in the maxilla in the (A), (B), and (C) regions.

Results:

The regenerate possessed anatomical and physiological characteristics equal to the parent bone. For the CTDO patients, prosthetic rehabilitation of the dentition was supported by dental implants after osseointegration of the latter into the newly created bone and soft tissue.

Discussion:

The production of the curvilinear bone and soft tissue along a horizontal plane has been demonstrated. The new alveolar bone achieved the correct width and depth to create a physiological vestibule and a functional/esthetic zone for the placement of dental implants. In addition, the shape of the palatal vault was also maintained. The CTDO method is a reliable method of maxillary reconstruction and has a better anatomical and functional outcome than the RFFF.