Surgical reconstructive treatment for infraosseous peri-implantitis defects with a submerged healing approach: A prospective controlled study

Background: The aim of this study was to assess the reconstructive potential of a submerged healing approach for the treatment of infraosseous peri-implantitis defects. Methods: Patients with a diagnosis of peri-implantitis were recruited. Implant suprastructures were removed before the surgical treatment, which included implant surface and defect detoxification using implantoplasty, air-power driven devices, and locally delivered antibiotics. The augmentation procedure included a composite bone graft and a non-resorbable membrane followed by primary wound coverage and a submerged healing of 8 months, at which point membranes were removed, and peri-implant defect measurements were obtained as the primary outcome. Secondary endpoints included assessment of cone-beam computed tomography (CBCT) and probing depth (PD) reductions. Results: Thirty implants in 22 patients were treated. A significant clinical bone gain of 3.22 ± 0.41 mm was observed at 8 months. Radiographic analysis also showed an average gain of 3.47 ± 0.41 mm. Three months after installment of new crowns, final PD measures showed a significant reduction compared to initial examinations and a significant reduction in bleeding on probing compared to examinations at the pre-surgical visit. Conclusions: Reconstruction of infraosseous peri-implantitis defects is feasible with thorough detoxification of implant sites, and a submerged regenerative healing approach.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/169155/1/Wen et al. 2021.pdfDescription of Wen et al. 2021.pdf : Full text of published articleSEL

An automated 3D-printed perfusion bioreactor combinable with pulsed electromagnetic field stimulators for bone tissue investigations

In bone tissue engineering research, bioreactors designed for replicating the main features of the complex native environment represent powerful investigation tools. Moreover, when equipped with automation, their use allows reducing user intervention and dependence, increasing reproducibility and the overall quality of the culture process. In this study, an automated uni-/bi-directional perfusion bioreactor combinable with pulsed electromagnetic field (PEMF) stimulation for culturing 3D bone tissue models is proposed. A user-friendly control unit automates the perfusion, minimizing the user dependency. Computational fluid dynamics simulations supported the culture chamber design and allowed the estimation of the shear stress values within the construct. Electromagnetic field simulations demonstrated that, in case of combination with a PEMF stimulator, the construct can be exposed to uniform magnetic fields. Preliminary biological tests on 3D bone tissue models showed that perfusion promotes the release of the early differentiation marker alkaline phosphatase. The histological analysis confirmed that perfusion favors cells to deposit more extracellular matrix (ECM) with respect to the static culture and revealed that bi-directional perfusion better promotes ECM deposition across the construct with respect to uni-directional perfusion. Lastly, the Real-time PCR results of 3D bone tissue models cultured under bi-directional perfusion without and with PEMF stimulation revealed that the only perfusion induced a ~ 40-fold up-regulation of the expression of the osteogenic gene collagen type I with respect to the static control, while a ~ 80-fold up-regulation was measured when perfusion was combined with PEMF stimulation, indicating a positive synergic pro-osteogenic effect of combined physical stimulation

An automated 3D-printed perfusion bioreactor combinable with pulsed electromagnetic field stimulators for bone tissue investigations

In bone tissue engineering research, bioreactors designed for replicating the main features of the complex native environment represent powerful investigation tools. Moreover, when equipped with automation, their use allows reducing user intervention and dependence, increasing reproducibility and the overall quality of the culture process. In this study, an automated uni-/bi-directional perfusion bioreactor combinable with pulsed electromagnetic field (PEMF) stimulation for culturing 3D bone tissue models is proposed. A user-friendly control unit automates the perfusion, minimizing the user dependency. Computational fluid dynamics simulations supported the culture chamber design and allowed the estimation of the shear stress values within the construct. Electromagnetic field simulations demonstrated that, in case of combination with a PEMF stimulator, the construct can be exposed to uniform magnetic fields. Preliminary biological tests on 3D bone tissue models showed that perfusion promotes the release of the early differentiation marker alkaline phosphatase. The histological analysis confirmed that perfusion favors cells to deposit more extracellular matrix (ECM) with respect to the static culture and revealed that bi-directional perfusion better promotes ECM deposition across the construct with respect to uni-directional perfusion. Lastly, the Real-time PCR results of 3D bone tissue models cultured under bi-directional perfusion without and with PEMF stimulation revealed that the only perfusion induced a similar to 40-fold up-regulation of the expression of the osteogenic gene collagen type I with respect to the static control, while a similar to 80-fold up-regulation was measured when perfusion was combined with PEMF stimulation, indicating a positive synergic proosteogenic effect of combined physical stimulations

Comparison of titanium dioxide scaffold with commercial bone graft materials through micro-finite element modelling in flow perfusion

TiO2 scaffolds have previously shown to have promising osteoconductive properties in previous in vivo experiments. Appropriate mechanical stimuli can further promote this osteoconductive behaviour. However, the complex mechanical environment and the mechanical stimuli enhancing bone regeneration for porous bioceramics have not yet been fully elucidated. This paper aims to compare and evaluate mechanical environment of TiO2 scaffold with three commercial CaP biomaterials, i.e. Bio-Oss, Cerabone and Maxresorb under simulated perfusion culture conditions. The solid phase and fluid phase were modelled as linear elastic material and Newtonian fluid, respectively. The mechanical stimulus was analysed within these porous scaffolds quantitatively. The results showed that the TiO2 had nearly heterogeneous stress distributions, however lower effective Young’s modulus than Cerabone and Maxresorb. The permeability and wall shear stress (WSS) for the TiO2 scaffold was significantly higher than other commercial bone substitute materials. Maxresorb and Bio-Oss showed lowest permeability and local areas of very high WSS. The detailed description of the mechanical performance of these scaffolds could help researchers to predict cell behaviour and to select the most appropriate scaffold for different in vitro and in vivo performances. © 2018 Springer Verla

Influencia de la presión de compactación durante la colocación del injerto óseo particulado en la angiogénesis y en la neoformación ósea en los procedimientos de regeneración ósea guiada

Introducción: En la actualidad, la compactación que se realiza sobre los injertos óseos particulados durante los procedimientos de regeneración ósea guiada se realiza de forma manual y no controlada, sin reparar en la fuerza que se ejerce sobre dichos biomateriales. El objetivo de este estudio fue, por tanto, el de mostrar si la fuerza de compresión en el empaquetamiento del injerto óseo particulado influye en los resultados de regeneración ósea en cuanto a la angiogénesis y a la neoformación ósea. Material y métodos: Para poder llevar a cabo el experimento in vivo, se diseñó, fabricó y calibró un instrumento compactador para uso clínico capaz de realizar la compactación de los injertos óseos particulados de una forma controlada y precisa, estandarizando así este procedimiento. Tras la comprobación con diversos estudios in vitro de la diferente reorganización de las partículas con el empleo de diferentes fuerzas de compresión, se procedió a la realización de un estudio in vivo. Para ello se fijaron dos cilindros de titanio en la calota de 8 conejos de Nueva Zelanda. Los defectos resultantes eran de 6,9 mm de diámetro y 4 mm de altura. Ambos defectos se rellenaron con partículas de hidroxiapatita bovina sometidas a una fuerza de compresión de 0,7 kg/cm2 o de 1,6 kg/cm2 antes de cubrirse con una membrana de colágeno reabsorbible. A las 6 semanas los animales fueron sacrificados y se evaluaron los resultados histológicamente en dos zonas de interés, la porción más próxima a la calota (ROI1) y la más alejada (ROI2), en el cuerpo del cilindro.Resultados: Se observó que junto a la bóveda craneal (ROI1), la neoformación ósea (NBF) fue de 29,0% ± 8,8% y de 27,6% ± 8,2% tras emplear una baja y una alta fuerza de compresión, respectivamente; el contacto hueso-biomaterial (BBC) fue de 58,2% ± 25,0% y de 69,3% ± 22,9%, respectivamente (p > 0,05). En el área más alejada de la calota junto a la membrana de colágeno (ROI2), la NBF fue de 4,9% ± 5,1% y de 5,7% ± 4,7% tras emplear una baja y una alta fuerza de compresión respectivamente y el BBC fue de 18,3% ± 20,8% y de 20,1% ± 15,9% (p > 0,05). Además, el número y el área de los vasos sanguíneos no se vieron afectados significativamente por estas fuerzas de compresión. Conclusión: Según los resultados obtenidos y teniendo en cuenta las limitaciones del estudio, se puede concluir que ambas fuerzas de compresión aplicadas dieron como resultado una consolidación similar de la hidroxiapatita bovina expresada por la formación de nuevo hueso y la vascularización según un modelo de aumento de la bóveda craneal de conejo.<br /