Synergic Action of Systemic Risedronate and Local Rutherpy in Peri-implantar Repair of Ovariectomized Rats: Biomechanical and Molecular Analysis.

Postmenopausal osteoporosis and poor dietary habits can lead to overweightness and obesity. Bisphosphonates are the first-line treatment for osteoporosis. However, some studies show that they may increase the risk of osteonecrosis of the jaw. Considering the antimicrobial, angiogenic and vasodilatory potential of nitric oxide, this study aims to evaluate the local activity of this substance during the placement of surface-treated implants. Seventy-two Wistar rats were divided into three groups: SHAM (SHAM surgery), OVX + HD (ovariectomy + cafeteria diet), and OVX + HD + RIS (ovariectomy + cafeteria diet + sodium risedronate treatment), which were further subdivided according to the surface treatment of the future implant: CONV (conventional), TE10, or TE100 (TERPY at 10 or 100 µM concentration); n = 8 per subgroup. The animals underwent surgery for implant installation in the proximal tibia metaphysis and were euthanized after 28 days. Data obtained from removal torque and RT-PCR (OPG, RANKL, ALP, IBSP and VEGF expression) were subjected to statistical analysis at 5% significance level. For biomechanical analysis, TE10 produced better results in the OVX + HD group (7.4 N/cm, SD = 0.6819). Molecular analysis showed: (1) significant increase in OPG gene expression in OVX groups with TE10; (2) decreased RANKL expression in OVX + HD + RIS compared to OVX + HD; (3) significantly increased expressions of IBSP and VEGF for OVX + HD + RIS TE10. At its lowest concentration, TERPY has the potential to improve peri-implant conditions.

Polydioxanone Membrane Compared with Collagen Membrane for Bone Regeneration.

Guided bone regeneration (GBR) is an approach that induces osteopromotion through the regenerative membranes. These barriers exhibit bioactive behavior and mechanical function. Polydioxanone is a synthetic option, already used in medicine and dentistry, with good results in bone regeneration. This study aimed to evaluate bone repair in critical defects in rat calvaria using a polydioxanone membrane (Plenum® Guide) compared with a commercially available collagen-based membrane (Bio-Gide®). The bone defects were filled with Plenum® Osshp, a synthetic bone graft, hydroxyapatite:ß-tricalcium phosphate, 70:30%, Group PG (Plenum® Guide + Plenum® Osshp), and Group BG (Geistlich Bio-Gide® + Plenum® Osshp). The specimens were submitted to immunohistochemical (RUNX2 and OPN), gene expression (RUNX2, IBSP, and VEGF), histometric, and microtomography analyses after 07, 15, 30, and 60 days postoperative. PG group showed greater immunolabeling area for RUNX2 and OPN, higher gene expression of VEGF (3.15 ± 0.85), and IBSP (24.9 ± 0.59). However, there was no statistical difference between groups in the histometric analysis regarding the percentage of connective tissue PG (0.83 ± 0.45), BG (0.70 ± 0.34), neoformed bone PG (0.60 ± 0.4), BG (0.65 ± 0.51), and remaining biomaterial PG (0.84 ± 0.31), BG (0.91 ± 0.33). In addition, there was no statistical difference between groups by micro-CT analysis. The absorbable-synthetic membrane, Plenum® Guide, is an effective membrane for guided bone regeneration.

PTH 1-34-functionalized bioactive glass improves peri-implant bone repair in orchiectomized rats: Microscale and ultrastructural evaluation.

The objective of this work was to investigate the use of Biogran® functionalized with parathyroid hormone (PTH) 1-34 by sonochemistry for the local delivery of this anabolic agent to the implant site. The effects of Biogran® and topical administration of PTH 1-34 on peri-implant bone regeneration were evaluated from the microscale to ultrastructural levels in healthy (SHAM) and orchiectomized (ORQ). While some animals only received a titanium implant in their tibial metaphyses (CLOT group), in others the peri-implant defect was first filled with Biogran® either without or with PTH 1-34 functionalization (BG and BGPTH groups, respectively) prior to implant installation. Osseointegration was characterized from a biomechanical perspective by measuring the removal torque with the counter-torque technique. Micro-CT was used to evaluate the percentage of bone volume, trabecular thickness, number and separation, and bone-implant contact (BIC). Dynamics of new bone formation were assessed by measuring fluorochrome area, daily mineral apposition rate, and neoformed bone area using confocal laser microscopy. RT-PCR was performed to evaluate ALP and osteocalcin expression. The interface between newly formed bone and Biogran® was examined using scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) at the micro-and nanoscale, respectively, while elemental analyses were completed in SEM with energy-dispersive X-ray spectroscopy (EDS). STEM imaging demonstrated the intimate attachment of bone to Biogran® (nanoscale level). Overall, the results suggest that the effectiveness of the topical administration of PTH 1-34 at the implant site seems enhanced in osteoporotic bone, promoting peri-implant bone regeneration to comparable levels in healthy conditions.

Improvement of Peri-Implant Repair in Estrogen-Deficient Rats Fed a Cafeteria Diet and Treated with Risedronate Sodium.

(1) Background: Postmenopausal osteoporosis combined with an unhealthy lifestyle can lead to the development of metabolic syndrome, a common condition in individuals requiring oral rehabilitation. Bisphosphonates are used to increase bone mineral density. However, further studies are needed to evaluate the action of this drug on the bone repair process in the jaws. The aim of this study was to evaluate the peri-implant repair of rats with estrogen deficiency and metabolic syndrome treated with risedronate sodium. (2) Methods: Twenty-four female Wistar rats were divided into three groups: SHAM: sham surgery; OVX/SM: ovariectomy combined with a cafeteria diet; OVX/SM/RIS: ovariectomy associated with a cafeteria diet and treatment with sodium risedronate. After 30 days, the animals underwent extraction of the upper first molars. Thirty days after the extraction, an implant was installed in the same region. Sixty days after the implant was installed, the animals were euthanized for biomechanical analysis and confocal microscopic analysis. After confirming the normal distribution of the sample data, a one-way ANOVA test was performed, followed by Tukey's post-test, with a 5% significance level. (3) Results: Significant bone preservation was observed in the risedronate-treated group. Higher removal torque values were obtained by the risedronate-treated group. (4) Conclusions: Better biomechanical performance of the implants installed in the animals treated with risedronate sodium was observed.

Avaliação das respostas de biomineralização pelo Rubus coreanus frente à deficiência de estrógeno: um estudo translacional / Evaluation of biomineralization responses by Rubus coreanus to estrogen deficiency: a translational study

Caracterização da ação local do Rubus coreanus através da funcionalização da superfície dos implantes a serem instalados. Realizado em 2 etapas. Na primeira etapa, foi realizada a caracterização da superfície de implantes funcionalizadas pelos fármacos, a partir de teste físico químico e testes biológicos em culturas de células. Para a cultura de células foram utilizadas células mesenquimais indiferenciadas, isoladas de fêmures de ratas. Foram avaliadas a atividade e a diferenciação celular. Posteriormente, foi realizada a segunda etapa onde foram executados os experimentos in vivo. Para tanto, foram utilizadas 80 ratas Wistar adultas jovens, fêmeas, sendo 32 ratas para o primeiro período de eutanásia (14 dias), e 48 ratas para o segundo período de eutanásia (28 dias). Os grupos experimentais são: SHAM CONV, SHAM DMSO, SHAM RC 200, SHAM RC 400, OVX CONV, OVX DMSO, OVX RC 200 e OVX RC 400, sendo que os animais OVX foram submetidos a ovariectomia bilateral, enquanto que os animais SHAM foram submetidos à cirurgia fictícia de ovariectomia bilateral. Passados 30 dias, todos animais foram submetidos à cirurgia de instalação dos implantes nas metáfises tibiais. Os implantes tiveram as superfícies tratadas com DMSO ou RC 200 ou RC 400, e houve o controle negativo realizado através dos implantes convencionais. A eutanásia dos animais do primeiro período de eutanásia aconteceu aos 14 dias após a instalação dos implantes e as tíbias foram destinadas para a análise biomecânica (contra-torque). Para os animais do segundo período de eutanásia, aos 28 dias após a instalação dos implantes foi realizada a eutanásia dos animais, e as tíbias foram destinadas para as seguintes análises: biomecânica (contra-torque), enquanto do lado contralateral foi realizada a microtomografia computadorizada para avaliação morfométrica do osso formado ao redor dos implantes instalados. Os dados quantitativos foram submetidos ao teste de homocedasticidade para a seleção do teste estatístico apropriado (paramétrico ou não paramétrico), com nível de significância de 5%. Através das análises biomecânica e microtomográfica foi possível verificar resultados semelhantes entre os grupos experimentais. Contudo, o rubus coreanus não foi capaz de atuar de forma positiva no processo de reparo ósseo perimplantar(AU)

Characterization of the local action of Rubus coreanus through the functionalization of the surface of the implants to be installed. Carried out in 2 steps. In the first stage, the characterization of the surface of implants functionalized by drugs was carried out, based on physical-chemical tests and biological tests on cell cultures. For cell culture, undifferentiated mesenchymal cells, isolated from femurs of rats, were used. Cell activity and differentiation were evaluated. Subsequently, the second stage was carried out, where the in vivo experiments were performed. For that, 80 young adult female Wistar rats were used, 32 rats for the first period of euthanasia (14 days), and 48 rats for the second period of euthanasia (28 days). The experimental groups are: SHAM CONV, SHAM DMSO, SHAM RC 200, SHAM RC 400, OVX CONV, OVX DMSO, OVX RC 200 and OVX RC 400, with the OVX animals undergoing bilateral ovariectomy, while the SHAM animals underwent submitted to sham surgery of bilateral ovariectomy. After 30 days, all animals underwent surgery to install the implants in the tibial metaphysis. The implants had their surfaces treated with DMSO or RC 200 or RC 400, and there was a negative control performed using conventional implants. The animals from the first period of euthanasia were euthanized 14 days after implant placement and the tibiae were destined for biomechanical analysis (counter-torque). For animals in the second period of euthanasia, 28 days after implant placement, the animals were euthanized, and the tibiae were destined for the following analyses: biomechanics (counter-torque), while on the contralateral side, computerized microtomography was performed for morphometric evaluation of the bone formed around the installed implants. Quantitative data were submitted to the homoscedasticity test to select the appropriate statistical test (parametric or non-parametric), with a significance level of 5%. Through biomechanical and microtomographic analyzes it was possible to verify similar results between the experimental groups. However, rubus coreanus was not able to act positively in the peri-implant bone repair process(AU)