Periodontal regeneration is still a challenge for periodontists and tissue engineers, as it requires the simultaneous restoration of different tissues-namely, cementum, gingiva, bone, and periodontal ligament (PDL). Here, we synthetized a chitosan (CH)-based trilayer porous scaffold to achieve periodontal regeneration driven by multitissue simultaneous healing. We produced 2 porous compartments for bone and gingiva regeneration by cross-linking with genipin either medium molecular weight (MMW) or low molecular weight (LMW) CH and freeze-drying the resulting scaffolds. We synthetized a third compartment for PDL regeneration by CH electrochemical deposition; this allowed us to produce highly oriented microchannels of about 450-µm diameter intended to drive PDL fiber growth toward the dental root. In vitro characterization showed rapid equilibrium water content for MMW-CH and LMW-CH compartments (equilibrium water content after 5 min >85%). The MMW-CH compartment degraded more slowly and provided significantly more resistance to compression (28% ± 1% of weight loss at 4 wk; compression modulus H = 18 ± 6 kPa) than the LMW-CH compartment (34% ± 1%; 7.7 ± 0.8 kPa) as required to match the physiologic healing rates of bone and gingiva and their mechanical properties. More than 90% of all human primary periodontal cell populations tested on the corresponding compartment survived during cytocompatibility tests, showing active cell metabolism in the alkaline phosphatase and collagen deposition assays. In vivo tests showed high biocompatibility in wild-type mice, tissue ingrowth, and vascularization within the scaffold. Using the periodontal ectopic model in nude mice, we preseeded scaffold compartments with human gingival fibroblasts, osteoblasts, and PDL fibroblasts and found a dense mineralized matrix within the MMW-CH region, with weakly mineralized deposits at the dentin interface. Together, these results support this resorbable trilayer scaffold as a promising candidate for periodontal regeneration.
This study has revealed that oral implants may osseointegrate equally well irrespective of whether their bed was prepared utilizing conventional drills with abundant cooling or Piezosurgery(®). Moreover, the surface coating of implants with dendrimers phosphoserine and polylysine did not improve osseointegration.
Background
Innovative customized computer‐aided design/computer‐assisted manufacture (CAD‐CAM) titanium meshes have been proposed for guided alveolar bone regeneration. Histological confirmation on the quality of the regenerated bone is needed. Purpose of the study is to assess the integration capabilities of these innovative meshes and to evaluate the histological features of the regenerated alveolar bone.
Materials and methods
Twenty partially edentulous patients, with severe posterior mandibular atrophy, underwent a guided bone regeneration technique by means of customized CAD‐CAM titanium mesh in association with a mixture of autologous bone in chips and deproteinized bovine bone (1:1). At 9 months of healing, titanium meshes and bone samples were collected and histomorphometrically analyzed.
Results
In all patients, implants were placed according to the original plan. At histologic analysis, mesh appeared well osseointegrated, except that in sites where membrane exposure occurred. In all sites, newly formed tissue resulted highly mineralized, well‐organized, and formed by 35.88% of new lamellar bone, 16.42% of woven bone, 10.88% of osteoid matrix, 14.10% of grafted remnants, and 22.72% of medullary spaces. Blood vessels were the 4% of the tissue.
Conclusions
Data from this study support the use of customized CAD/CAM titanium mesh for regeneration of vital, well‐structured, and vascularized alveolar bone.
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