The Influence of Storage in Saline or Irradiation by Ultraviolet on Implant Hydrophilicity and Osseointegration: An Experimental Study in Rabbits

Storage in aqueous solution or ultraviolet (UV) irradiation can re t ain or regain the hydrophilicity of titanium implant surface. In this study, t hree types of commercial titanium implants were used : ZBL (ZDI Bone L evel ® ), CEL (C-tech Esthetic Line ® ) , and modSLA (Straumann SLActive ® ). ZBL and CEL implants were treated with UV irradiation for 4 h. Surface characterization of the four groups (ZBL, ZBL-UV, CEL-UV, modSLA) was evaluated by scanning electron microscopy and contact angle measurements. The in vivo bone response was evaluated by removal torque (RTQ) tests and histomorphometric analysis at 3, 6 , and 12 weeks post-implantation. A total of 144 implants and 36 rabbits were used for experiments according to a previously established randomization sequence. The ZBL-UV, CEL-UV , andmodSLA groups were hydrophilic, and nanostructures were observed on the modSLA implant surface.ModSLA achieved better RTQ value than ZBL at 12 weeks ( p <0.05). For histomorphometric analysis, ZBL-UV and CEL-UV implants showed higher bone area values in the cancellous bone zone at 6 weeks than did modSLA and ZBL implants ( p <0.05).In the cortical bone zone, all groups showed comparable bone-to-implant contact at all healing time points ( p >0.05).Both storage in saline and UV irradiation could retain or provoke hydr o philic surfaces and improve osseointegration. Compared to storage in saline, UV irradiation displayed slight advantages in promoting new bone formation in cancellous bone zone at an early stage.

Involvement of Ischemia-driven 5LPOX-RvE1-ChemR23 axis in the resolution of post-CABG inflammation in Coronary Arteries

Aims: Expression status of pro-resolving lipid mediators (PLM) and receptors in the post-CABG coronary arteries are largely unknown. Here, we aim to investigate the expression of PLMs in the atherosclerotic post-CABG swine LAD compared to without CABG (LAD-AS), and in isolated coronary artery smooth muscle cells (CASMCs) cultured under ischemia. Methodology: The arteries of interest were harvested from post-CABG atherosclerotic swine and the histomorphology and the expression status of key PLM mediators were quantified using immunostaining. SMCs were cultured under ischemia and confirmed the expression on PLM mediators at transcript and protein level.Results: The histomorphometric analysis revealed considerable alterations in the tissue architecture in LAD-CABG and LAD-AS arteries compared to control. PLM synthetic enzyme 5LPOX was significantly upregulated in LAD-CABG and LAD-AS whereas the other mediators including 12LPOX, 15LPOX, COX2, ChemR23, GPCR18, GPCR120 were decreased in LAD-CABG than control. LPOX enzymes and PLM receptors were upregulated in ischemic CASMCs with respect to control. Western blot showed the upregulation of 5LPOX, and ChemR23. Additionally, higher level of RvE1 was observed in ischemic control CASMCs which was decreased following reperfusion. Conclusion: These findings suggest that the CASMCs withstand the ischemia-triggered proinflammatory episodes by increasing the secretion of RvE1 mediated through 5LPOX and ChemR23 signaling.

Osseointegration of Sandblasted and Acid-Etched Implant Surfaces. A Histological and Histomorphometric Study in the Rabbit

Titanium surface is an important factor in achieving osseointegration during the early wound healing of dental implants in alveolar bone. The purpose of this study was to evaluate sandblasted-etched surface implants to investigate the osseointegration. In the present study, we used two different types of sandblasted-etched surface implants, an SLA™ surface and a Nanoblast Plus™ surface. Roughness and chemical composition were evaluated by a white light interferometer microscope and X-ray photoelectron spectroscopy, respectively. The SLA™ surface exhibited the higher values (Ra 3.05 μm) of rugosity compared to the Nanoblast Plus™ surface (Ra 1.78 μm). Both types of implants were inserted in the femoral condyles of ten New Zealand white rabbits. After 12 weeks, histological and histomorphometric analysis was performed. All the implants were osseointegrated and no signs of infection were observed. Histomorphometric analysis revealed that the bone–implant contact % (BIC) ratio was similar around the SLA™ implants (63.74 ± 13.61) than around the Nanoblast Plus™ implants (62.83 ± 9.91). Both implant surfaces demonstrated a favorable bone response, confirming the relevance of the sandblasted-etched surface on implant osseointegration.

Clinical Efficacy of Polycaprolactone β-Calcium Triphosphate Composite for Osteoconduction in Rabbit Bone Defect Model

The combination of β-tricalcium phosphate (β-TCP) with polycaprolactone (PCL) has been considered a promising strategy for designing scaffolds for bone grafting. This study incorporated PCL with commercially available β-TCP (OsteoceraTM) to fabricate an injectable bone substitute and evaluate the effect of PCL on compressive strength and setting time of the hydraulic cement. The mechanical testing was compliant with the ASTM D695 and ASTM C191-13 standards. Results showed that PCL-TCP composite presented a well-defined architecture with uniform pore distribution and a significant increase in compressive strength compared with β-TCP alone. Eighteen rabbits, each with two surgically created bone defects, were treated using the PCL-TCP composites. The composite materials were resorbed and replaced by newly formed bone tissue. Both PCL-TCP and β-TCP demonstrated equivalent clinical effects on osteoconduction property in terms of the percentage of newly formed bone area measured by histomorphometric analysis. PCL-TCP was proven to be as effective as the commercially available β-TCP scaffold (OsteoceraTM).

Split-Block Graft Versus Cortico-cancellous Block Graft for Horizontal Ridge Augmentation: Cone Beam Computed Tomography and Histomorphometric Study

Objective: The aim of this study was to compare the horizontal dimensional changes of split-bone block and cortico-cancellous block graft in horizontal ridge augmentation using Cone Beam Computed Tomography (CBCT). The quality of the regenerated bone in both groups was compared histologically and histomorphometrically. Material and methods: Twenty patients were randomly divided in two equal groups (n= 10): Split-bone block group which was harvested from the external oblique ridge or cortico-cancellous block graft group which was harvested from the mandibular symphysis. Pre-augmentation crestal ridge width was measured using bone caliper. CBCT scans were taken on the 2nd week and 4th month post-operatively to measure crestal and total horizontal ridge dimensions. A biopsy was collected from the regenerated ridge immediately before implant insertion on the 4th month post-operatively. Results: Pre-augmentation crestal bone widths of both groups were comparable (P= 0.870). On the 2nd week and 4th month post-operatively, split-bone block showed a significantly wider crestal (P= 0.028 and P= 0.001 respectively) and total horizontal ridge dimension (P= 0.025 and P= 0.002 respectively), and on the 4th month post-operatively, it showed significantly lesser resorption at crest (P= 0.040) and in total horizontal ridge dimension (P= 0.017) than cortico-cancellous block. Histologically, the regenerated bone quality was similar in both groups. Histomorphometric analysis showed a non-significant difference in percentage of mature (P= 0.365) and immature collagen (P= 0.531) between both groups. Conclusion: Split-bone block maintained a significantly wider ridge and experienced less resorption after 4 months than the cortico-cancellous block graft, with no difference in regenerated bone quality between both groups. Keywords Dental implants; CBCT; Cortico-cancellous block graft; Histomorphometric analysis; Split-bone block technique.