Active and Passive Tuning of Ultranarrow Resonances in Polaritonic Nanoantennas

[EN] Optical nanoantennas are of great importance for photonic devices and spectroscopy due to their capability of squeezing light at the nanoscale and enhancing light-matter interactions. Among them, nanoantennas made of polar crystals supporting phonon polaritons (phononic nanoantennas) exhibit the highest quality factors. This is due to the low optical losses inherent in these materials, which, however, hinder the spectral tuning of the nanoantennas due to their dielectric nature. Here, active and passive tuning of ultranarrow resonances in phononic nanoantennas is realized over a wide spectral range (approximate to 35 cm(-1), being the resonance linewidth approximate to 9 cm(-1)), monitored by near-field nanoscopy. To do that, the local environment of a single nanoantenna made of hexagonal boron nitride is modified by placing it on different polar substrates, such as quartz and 4H-silicon carbide, or covering it with layers of a high-refractive-index van der Waals crystal (WSe2). Importantly, active tuning of the nanoantenna polaritonic resonances is demonstrated by placing it on top of a gated graphene monolayer in which the Fermi energy is varied. This work presents the realization of tunable polaritonic nanoantennas with ultranarrow resonances, which can find applications in active nanooptics and (bio)sensing.J.M.-S. acknowledges financial support from the Ramon y Cajal Program of the Government of Spain and FSE (Grant No. RYC2018-026196-I) and the Spanish Ministry of Science and Innovation (State Plan for Scientific and Technical Research and Innovation Grant Number PID2019-110308GA-I00). P.A.-G. acknowledges support from the European Research Council under starting Grant No. 715496, 2DNANOPTICA, and the Spanish Ministry of Science and Innovation (State Plan for Scientific and Technical Research and Innovation Grant Number PID2019-111156GB-I00). G.a.-P. and J.T.-G. acknowledge support through the Severo Ochoa Program from the Government of the Principality of Asturias (Grant nos. PA20-PF-BP19-053 and PA-18-PF-BP17-126, respectively). A.Y.N. acknowledges the Spanish Ministry of Science and Innovation (Grant Nos. MAT201788358-C3-3-R and PID2020-115221GB-C42) and the Basque Department of Education (Grant No. PIBA-2020-1-0014) J.H.E. acknowledges support for h-BN crystal growth from the National Science Foundation, Award Number CMMI-1538127. R.H. acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities (National Project Grant No. RTI2018-094830-B-100 and the Project Grant No. MDM-2016-0618 of the Marie de Maeztu Units of Excellence Program), the Basque Government (Grant No. IT1164-19), and the European Union's Horizon 2020 research and innovation programme under the Graphene Flagship (Grant Agreement Numbers 785219 and 881603, GrapheneCore2 and GrapheneCore3). I.D. acknowledges the Basque Government (Grant No. PRE_2019_2_0164). Work at MIT was partly supported through AFOSR Grant No. FA9550-16-1-0382, through the NSF QII-TAQS program (Grant No. 1936263), and the Gordon and Betty Moore Foundation EPiQS Initiative through Grant No. GBMF9643 to P.J.-H

The role of cortical perforations in allogeneic block grafting for lateral augmentation in maxilla: A randomized clinical trial

Abstract Background: The need of decortication on the recipient site remains unclear for bone regeneration. To our knowledge, there are no human clinical trials that studied the influence of decortication on cancellous allogeneic block grafting. Purpose: The aim of the present study is to evaluate the influence of perforating the cortex of the recipient site on cancellous allogeneic block graft integration and revas- cularization in the maxilla. Material and Methods: Twenty-six patients referred for lateral bone augmentation were included in this clinical trial. Patients received freeze-dried bone allograft can- cellous blocks obtained from the iliac crest; cortical perforations of the recipient bed were performed in the test group while in the control group it was left intact. After a 4-month healing period another surgery was performed to place dental implants, and a bone biopsy was collected using a trephine. All samples underwent micro-CT scans, and were processed for histomorphometric and immunohistochemical analysis. Implant survival comparisons were made using a repeated measures analysis of vari- ance (ANOVA) while all other variables were compared using the analysis of covari- ance (ANCOVA). Results: One hundred and nineteen implants were placed into 110 augmented sites. One hundred percent implant survival rate was reported during 24 months follow-up period. No differences were reported in bleeding on probing at 1 (5.6 vs 9%) and 2 years (13.2 vs 12.1%), probing pocket depth at 1 (3.4 ± 0.95 vs 3.6 ± 1.12 mm) and 2 years (3.8 ± 1.02 vs 4.1 ± 1.46 mm), and marginal bone loss at 1 (0.2 ± 0.52 vs 0.3 ± 0.57 mm) and 2 years (0.6 ± 0.91 vs 0.5 ± 0.87 mm). No statistically significant dif- ferences were found in the micro-CT and histomorphometric analysis in terms of newly formed bone (25.7 ± 11.2% vs 22.3 ± 9.7%), soft tissue (33.0 ± 14.7% vs 36.5 ± 15.7%), remnant allograft (39.3 ± 20.4% vs 41.2 ± 22.7%), and bone mineralization (57.2 ± 10.6% vs 53.8 ± 8.7%). Perforating the cortex of the recipient site had no sig- nificant effect on angiogenesis as shown by immunohistochemical analysis of CD34 positive blood vessels (39.21 ± 10.53/mm2 vs 34.16 ± 12.67/mm2). Conclusion: Cancellous allogeneic bone block grafts are a clinically acceptable alter- native for horizontal bone augmentation. Cortical perforations of the recipient site in the maxilla did not improve angiogenesis nor bone formation within the block graft.Depto. de Especialidades Clínicas OdontológicasFac. de OdontologíaTRUEpu

Clinical and radiographic outcomes of allogeneic block grafts for maxillary lateral ridge augmentation: A randomized clinical trial

Abstract Background: A main drawback of bone block graft surgery is the resorption occurring in early stages of healing. To our knowledge, there are no studies comparing out- comes of freeze-dried bone allograft (FDBA) blocks with different architecture. Purpose: The aim of this work was to investigate different factors that can affect graft resorption and to compare the resorption rates of two different types of alloge- neic blocks, corticocancellous and cancellous. Materials and Methods: A randomized clinical trial was designed. Twenty-eight patients referred for onlay bone augmentation prior to implant placement were included in the study. Preoperative computerized tomography (CT) was taken for all patients. Patients received FDBA blocks of either cancellous or corticocancellous bone obtained from the iliac crest. After a 4-month follow-up, postoperative CT was taken. Then, another surgery was performed, with the purpose to place dental implants. The aforementioned groups were compared for bone resorption and implant outcome using analysis of covariance (ANCOVA) and repeated ANOVA mea- sures, respectively. Demographic data, trabecular bone density, and graft sites were also analyzed. Results: A total of 93 implants were placed in the augmented bone sites over 28 patients. A 100% survival rate was achieved during a mean follow-up period of 24 months in both groups. Higher bone resorption rate was found with cancellous bone grafts (29.2%±2.6) compared with corticocancellous grafts (19.3%±2.3). Moreover, higher resorption rates in patients with lower bone density (185 Hounsfield Units) (16.8% ± 2.1) and nonsmokers (22.1% ± 2.3), respectively. Conclusion: Within the limitations of this study, these findings indicate that both corticocancellous and cancellous FDBA grafts constitute a clinical acceptable alterna- tive for bone reconstruction, although cancellous grafts present higher resorption rates. Moreover, host factors such as patient's low bone density and smoking habits may also increase graft resorption rates.Depto. de Especialidades Clínicas OdontológicasFac. de OdontologíaTRUEpu

Split bone block technique: 4-month results of a randomised clinical trial comparing clinical and radiographic outcomes between autogenous and xenogeneic cortical plates

Purpose: To evaluate short-term clinical and radiographic outcomes of bone regeneration procedures using thin cortical porcine xenogeneic bone plates in combination with autogenous bone chips compared with thin autogenous cortical plates and autogenous bone chips. Materials and methods: A total of 19 patients (12 women and 7 men, mean age 58.24 ± 3.09 years) were randomly allocated to two different groups regarding surgical procedure: autogenous cortical plates (ACP group) and xenogeneic cortical plates (XCP group). Preoperative CBCT scans were performed for each patient. Surgical time and postoperative pain were recorded, as well as tissue healing and graft resorption after 4 months, then another surgical procedure was performed to place dental implants. Data were analysed using an analysis of covariance. Results: Twenty-one surgical procedures were performed on 19 patients (10 from the XCP group and 9 from the ACP group). The operative time was significantly lower in the XCP group (25.45 ± 3.88 minutes) than in the ACP group (44.10 ± 3.60 minutes). The XCP group also showed less pain, but not significantly less, than the ACP group. The graft resorption rate in the ACP and XCP groups was 2.03 ± 1.58% and 3.49 ± 2.38% respectively, showing no statistically significant difference. Conclusions: Despite the limited sample size and non-uniform distribution between the maxilla and mandible as surgical sites, the results suggest that XCP and ACP grafts are similar in terms of bone volume gain and graft resorption rate, with no significant differences in wound healing or complication rate. Nevertheless, the XCP group recorded lower pain levels and required significantly less operative time compared to the ACP group.Depto. de Especialidades Clínicas OdontológicasFac. de OdontologíaTRUEpu

Periosteal Pocket Flap technique for lateral ridge augmentation. A comparative pilot study versus guide bone regeneration

Background: Implant rehabilitation of posterior mandibular defects is frequently associated to a horizontal bone loss. There exist several regenerative techniques to supply this bone deficiency, one of which is the Periosteal Pocket Flap Technique (PPF) proposed by Steigmann et al. to treat small horizontal bone defects. The present study proposes a modification of this technique based on the concurrent use of PPF with the use of xenogeneic and autologous bone and Plasma Rich in Growth Factors (PRGF). The aim of this study is to evaluate clinical and radiographic outcomes of the PPF with the use of xenogeneic and autologous bone and PRGF in comparison with conventional Guided Bone Regeneration (GBR) procedures. Methods: Nine patients were enroled in the study (7 women and 2 men, mean age: 53 ± 2.74 years) and allocated to PPF or GBR. In both groups implant placement was performed simultaneously to bone regeneration. Preoperative CBCT scans were performed for each patient. Surgical time and postoperative pain were recorded, as well as tissue healing. Moreover, horizontal bone gain (mm), graft surface area (mm2) and graft volume (mm3) were evaluated. Results: Nine surgeries were performed: 6 PPF and 3 GBR. Regarding clinical outcomes, operative time was significative greater in GBR group than in PPF group (51.67 ± 3.51 min vs. 37 ± 5.69 min; p = 0.008). Postoperative pain was higher in GBR compared to PPF (p = 0.011). Regarding radiographical results, there were not significant differences in horizontal bone gain (PPF: 9.43 ± 1.8 mm; GBR: 9.28 ± 0.42 mm), surface area (PPF: 693.33 ± 118.73 mm2; GBR: 655.61 ± 102.43 mm2), and volume (PPF: 394.97 ± 178.72 mm3; GBR: 261.66 ± 118 mm3) between groups. Conclusions: This prospective study demonstrates that the combination of autograft/xenograft and PRGF in PPF technique is a simpler, cheaper, and faster technique than GBR technique for achieving moderate lateral bone augmentation in implant treatment. Future randomised clinical studies are needed to confirm the results.Depto. de Especialidades Clínicas OdontológicasFac. de OdontologíaTRUEpu