Knowledge about COVID-19 and pandemic impact on Madrid dental students (Spain)

COVID-19 has had a major impact on dental activity, with implications on dental education. The aim of this study was to assess the knowledge about it and the pandemic impact on Spanish dental students. An observational and cross-sectional study with a 1

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

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

Active and Passive Tuning of Ultranarrow Resonances in Polaritonic Nanoantennas

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 (≈35 cm-1 , being the resonance linewidth ≈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