Patterns of antibiotic prescription in implant dentistry and antibiotic resistance awareness among European dentists: A questionnaire-based study

OBJECTIVES

Antimicrobial resistance is an alarming global public health concern, threatening the effective treatment of common infections. This phenomenon is driven by the improper prescription of antibiotics. This study aimed to elucidate the patterns of antibiotic prescription in implant dentistry among European dentists and their awareness of antibiotic resistance.

MATERIALS AND METHODS

An anonymous online validated questionnaire was distributed via e-mail to 6431 recipients through the European Association for Osseointegration. It comprised of 17 structured questions investigating demographic variables, working environment, clinical experience, attitude towards antibiotic prescription in particular in relation to implant dentistry and COVID-19 pandemic, and awareness of antibiotic resistance. Data were collected from April to May 2023.

RESULTS

281 dentists from 33 European countries completed the survey. Almost 80% affirmed to routinely prescribe antibiotics as prophylaxis as well as after dental implant placement, especially in medically compromised patients or in cases of bone grafting. Amoxicillin, alone (61%) or in combination with clavulanic acid (56%), was the most common antibiotic of choice. Awareness of penicillin resistance among respondents was high. For peri-implantitis treatment, more than half reported the use of systemic antibiotics. The large majority (95%) did not prescribe more antibiotics since the beginning of COVID-19 pandemic. Less than 40% declared to follow national guidelines for antibiotic prescription.

CONCLUSION

This survey revealed a high prescription rate of antibiotics in implant dentistry, despite the awareness about antibiotic resistance among the respondents. The development and adherence to European guidelines has been identified as a potential strategy for improving antimicrobial stewardship.

Eligibility and efficacy of a CPC- and CHX-based antiviral mouthwash for the elimination of SARS-CoV-2 from the saliva: A randomized, double-blind, controlled clinical trial

AIM

This study aimed at investigating the efficacy of a 0.05% cetylpyridinium chloride-0.05% chlorhexidine (CPC-CHX) mouthwash in reducing viral load in the saliva as compared with sterile water.

MATERIALS AND METHODS

Forty SARS-CoV-2 positive patients were asked to dispense 4 mL of saliva. Half the patients rinsed for 60 s with 15 mL CPC-CHX, and the remaining patients rinsed with sterile water (control). Four millilitres of saliva were collected after 15, 30 and 60 min after rinsing. Quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) specific for SARS-CoV-2 nucleocapsid protein were performed. For ELISA, the intact (representing the active virus) to total virus load (I/T) was calculated.

RESULTS

SARS-CoV-2 copy numbers/mL from RT-qPCR tended to decrease in the control group, whereas in the CPC-CHX group, an increase was observed after T30. However, mixed linear model analysis revealed no statistical differences between groups (p = .124), time points (p = .616) and vaccinated or non-vaccinated patients (p = .953). Similarly, no impact of group (p = .880), time points (p = .306) and vaccination (p = .711) was observed for I/T ratio values.

CONCLUSIONS

Within the limitation of this study, there was no evidence that the intervention reduced salivary SARS-CoV-2 viral load during the course of 60 min. Therefore, commonly used pre-procedural rinsing might not be clinically relevant.

Micro finite element analysis of continuously loaded mini-implants - A micro-CT study in the rat tail model

Implant migration has been described as a minor displacement of orthodontic mini-implants (OMIs) when subjected to constant forces. Aim of this study was to evaluate the impact of local stresses on implant migration and bone remodelling around constantly loaded OMIs. Two mini-implants were placed in one caudal vertebra of 61 rats, connected by a nickel‑titanium contraction spring, and loaded with different forces (0.0, 0.5, 1.0, 1.5 N). In vivo micro-CT scans were taken immediately and 1, 2 (n = 61), 4, 6 and 8 (n = 31) weeks post-op. Nine volumes of interest (VOIs) around each implant were defined. To analyse stress values, micro-finite element models were created. Bone remodelling was analysed by calculating the bone volume change between scans performed at consecutive time points. Statistical analysis was performed using a linear mixed model and likelihood-ratio-tests, followed by Tuckey post hoc tests when indicated. The highest stresses were observed in the proximal top VOI. In all VOIs, stress values tended to reach their maximum after two weeks and decreased thereafter. Bone remodelling analysis revealed initial bone loss within the first two weeks and bone gain up to week eight, which was noted especially in the highest loading group. The magnitude of local stresses influenced bone remodelling and it can be speculated that the stress related bone resorption favoured implant migration. After a first healing phase with a high degree of bone resorption, net bone gain representing consolidation was observed.

Efficacy of different mouthwashes against COVID-19: A systematic review and network meta-analysis

To evaluate the effectiveness of antiseptic mouthwashes in reducing SARS-CoV-2 load clinically and in vitro. A systematic electronic search (MEDLINE/Scopus/Cochrane) was conducted to identify prospective clinical and in vitro studies published between 2019 included and 16 June 2023 assessing the effectiveness of mouthwashes in reducing SARS-CoV-2 load in saliva or surrogates. Data were summarized in tables and a network meta-analysis was performed for clinical trials. Thirty-five studies (14 RCTs, 21 in vitro) fulfilled the inclusion criteria. The risk of bias was judged to be high for 2 clinical and 7 in vitro studies. The most commonly test product was chlorhexidine alone or in combination with other active ingredients, followed by povidone-iodine, hydrogen peroxide and cetylpyridinium chloride. Overall, the descriptive analysis revealed the effectiveness of the mouthwashes in decreasing the salivary viral load both clinically and in vitro. Network meta-analysis demonstrated a high degree of heterogeneity. Among these studies, only chlorhexidine 0.20% was associated to a significant Ct increase in the saliva 5 min after rinsing compared to non-active control (p = 0.027). Data from clinical and in vitro studies suggested the antiviral efficacy of commonly used mouthwashes. Large well-balanced trials are needed to identify the best rinsing protocols.

In vitro evaluation of granules obtained from 3D sphene scaffolds and bovine bone grafts: chemical and biological assays

Sphene is an innovative bone graft material. The aim of this study was to investigate and compare the physicochemical and biological properties of Bio-Oss® (BO) and in-lab synthesized and processed sphene granules. BO granules of 1000-2000 μm (BO-L), 250-1000 μm (BO-S) and 100-200 μm (BO-p) for derived granules, and corresponding groups of sphene granules obtained from 3D printed blocks (SB-L, SB-S, SB-p) and foams (SF-L, SF-S and SF-p) were investigated. The following analyses were conducted: morphological analysis, specific surface area and porosity, inductively coupled plasma mass spectrometry (ICP-MS), cytotoxicity assay, Alizarin staining, bone-related gene expression, osteoblast migration and proliferation assays. All pulverized granules exhibited a similar morphology and SF-S resembled natural bone. Sphene-derived granules showed absence of micro- and mesopores and a low specific surface area. ICP-MS revealed a tendency for absorption of Ca and P for all BO samples, while sphene granules demonstrated a release of Ca. No cellular cytotoxicity was detected and osteoblastic phenotype in primary cells was observed, with significantly increased values for SF-L, SF-S, BO-L and BO-p. Further investigations are needed before clinical use can be considered.

Autoclaving-induced dimensional changes of three-dimensional printed surgical guides: An in vitro study

OBJECTIVES

Surgical guides are frequently used for dental implant placement. The aim of this study was to evaluate the impact of the 3D printing process itself and subsequent steam autoclaving on the dimensional stability of five different resin/printer combinations (RPCs).

MATERIALS AND METHODS

Fifty identical surgical guides (10 per group) were produced consisting of five RPCs. Half of the guides (5 per group) were steam autoclaved with cycle 1 (121°C, 1 bar, 20.5 min) and the other half with cycle 2 (134°C, 2 bar, 5.5 min). All guides were scanned with a structured-light (SL) 3D scanner before (T0) and after (T1) autoclaving. Linear measurements along the x-, y-, and z-axes were performed at landmarks on the original STL file and on SL scans at T0 and T1, respectively. Wilcoxon signed-rank test, Kruskal-Wallis test, and linear mixed-effects models were performed, depending on the analysis.

RESULTS

Three-dimensional printing was associated with significant dimensional alterations for all RPCs. Steam autoclaving using cycle 1 was associated with significant shrinkage in x- (1 RPC), y- (2 RPCs), and z-direction (2 RPCs), while cycle 2 was also associated with shrinkage in x- (2 RPCs), y- (1 RPC), and z-direction (1 RPC). One resin did not present any dimensional changes independently of the cycle.

CONCLUSIONS

The majority of the guides presented minor but significant shrinkage due to 3D printing itself and both steam autoclaving cycles, the extent varied between different RPCs. Whether these changes compromise implant placement accuracy remains to be investigated.

Two-piece zirconia implants in the posterior mandible and maxilla: A cohort study with a follow-up period of 9 years

OBJECTIVES

Long-term follow-up observations of zirconia implants are rare. This study aimed at evaluating the clinical performance of two-piece zirconia implants in the posterior jaws over 9 years.

MATERIALS AND METHODS

Sixty partially edentulous patients were treated with two-piece zirconia implants. In eight no primary stability could be achieved. Fifty-two patients received the final restoration (i.e., cemented fibreglass abutments and all-ceramic crowns). After 2 years, 2 implants failed and 4 dropouts were recorded. The remaining 46 patients with one target implant each were recalled at 9 years. Besides implant survival, clinical parameters at the implant level (plaque index-PI, bleeding on probing-BOP, probing depth-PD, mucosal recession-MR) were recorded and compared with previously collected data. Mechanical and technical complications were assessed.

RESULTS

Thirty patients responded. The mean observation period was of 111.1 ± 2.2 months. One implant was lost. Data recorded from the remaining 29 implants were analysed. PI values increased overtime. Mean BOP and PD remained unchanged during follow-up. No additional cases of peri-implantitis were recorded over the 10 diagnosed during the first 2 years of follow-up. No significant changes in mean MR values were detected over time, with 65% of the all included implants exhibiting no recession at 9 years and all the others, but one, a maximum MR of 1 mm. Three technical and 6 mechanical complications occurred in 7 patients between 2- and 9-years (6.9% and 20.7%, respectively, at patient level).

CONCLUSION

Within the limitations of the present study, a high survival rate was registered. Albeit frequent mechanical and technical complications, two-piece zirconia implants could represent a valid solution for the replacement of single teeth in the posterior jaws.

Peri-Implant Bone Loss and Overload: A Systematic Review Focusing on Occlusal Analysis through Digital and Analogic Methods

The present review aimed to assess the possible relationship between occlusal overload and peri-implant bone loss. In accordance with the PRISMA guidelines, the MEDLINE, Scopus, and Cochrane databases were searched from January 1985 up to and including December 2021. The search strategy applied was: (dental OR oral) AND implants AND (overload OR excessive load OR occlusal wear) AND (bone loss OR peri-implantitis OR failure). Clinical studies that reported quantitative analysis of occlusal loads through digital contacts and/or occlusal wear were included. The studies were screened for eligibility by two independent reviewers. The quality of the included studies was assessed using the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool. In total, 492 studies were identified in the search during the initial screening. Of those, 84 were subjected to full-text evaluation, and 7 fulfilled the inclusion criteria (4 cohort studies, 2 cross-sectional, and 1 case-control). Only one study used a digital device to assess excessive occlusal forces. Four out of seven studies reported a positive correlation between the overload and the crestal bone loss. All of the included studies had moderate to serious overall risk of bias, according to the ROBINS-I tool. In conclusion, the reported data relating the occlusal analysis to the peri-implant bone level seem to reveal an association, which must be further investigated using new digital tools that can help to standardize the methodology.

Volumetric analysis of the periodontal microstructure under antiresorptive therapy: an experimental study in rabbits

OBJECTIVES

The objective of this study was to volumetrically assess changes in the periodontal microstructure under antiresorptive therapy.

MATERIALS AND METHODS

Microtomographic scans from a total of 9 Dutch Belted rabbits having been randomly allocated to either the intravenous administration of amino-bisphosphonate (zoledronic acid) (Za) (n = 5) or a negative control group (nZa) (n = 4) were obtained at 10 months following a repeated drug administration. A quantification of the periodontal space thickness (P.Th) of both maxillary and mandibular most posterior premolars, as well as of the 2nd molars was performed. Bone micromorphometry was assessed by means of bone volume per total volume (BV/TV), the bone mineral density (BMD), trabecular thickness (Tb.Th), trabecular number (Tb.N), bone surface (BS), and the specific bone surface (BS/BV).

RESULTS

Za was associated with significantly higher P.Th (P = 0.010), which was most pronounced in the upper jaw. Bone micromorphometry revealed no significant differences among the two groups, i.e., Za and nZa, for all the investigated parameters.

CONCLUSIONS

Volumetric analysis revealed that antiresorptive therapy was associated with periodontal space widening, whereas major effects on the bone micro-morphology could not be observed.

CLINICAL RELEVANCE

A deep understanding of specific periodontal and alveolar bone alterations in patients under antiresorptive therapy might help to prevent the onset of medication-related osteonecrosis of the jaw.

Exosomes Derived from Dental Pulp Stem Cells Show Different Angiogenic and Osteogenic Properties in Relation to the Age of the Donor

Craniofacial tissue reconstruction still represents a challenge in regenerative medicine. Mesenchymal stem cell (MSC)-based tissue engineering strategies have been introduced to enhance bone tissue repair. However, the risk of related complications is limiting their usage. To overcome these drawbacks, exosomes (EXOs) derived from MSCs have been recently proposed as a cell-free alternative to MSCs to direct tissue regeneration. It was hypothesized that there is a correlation between the biological properties of exosomes derived from the dental pulp and the age of the donor. The aim of the study was to investigate the effect of EXOs derived from dental pulp stem cells of permanent teeth (old donor group) or exfoliated deciduous teeth (young donor group) on MSCs cultured in vitro. Proliferation potential was evaluated by doubling time, and commitment ability by gene expression and biochemical quantification for tissue-specific factors. Results showed a well-defined proliferative influence for the younger donor aged group. Similarly, a higher commitment ability was detected in the young group. In conclusion, EXOs could be employed to promote bone regeneration, likely playing an important role in neo-angiogenesis in early healing phases.

Nanostructured Modifications of Titanium Surfaces Improve Vascular Regenerative Properties of Exosomes Derived from Mesenchymal Stem Cells: Preliminary In Vitro Results

(1) Background: Implantation of metal-based scaffolds is a common procedure for treating several diseases. However, the success of the long-term application is limited by an insufficient endothelialization of the material surface. Nanostructured modifications of metal scaffolds represent a promising approach to faster biomaterial osteointegration through increasing of endothelial commitment of the mesenchymal stem cells (MSC). (2) Methods: Three different nanotubular Ti surfaces (TNs manufactured by electrochemical anodization with diameters of 25, 80, or 140 nm) were seeded with human MSCs (hMSCs) and their exosomes were isolated and tested with human umbilical vein endothelial cells (HUVECs) to assess whether TNs can influence the secretory functions of hMSCs and whether these in turn affect endothelial and osteogenic cell activities in vitro. (3) Results: The hMSCs adhered on all TNs and significantly expressed angiogenic-related factors after 7 days of culture when compared to untreated Ti substrates. Nanomodifications of Ti surfaces significantly improved the release of hMSCs exosomes, having dimensions below 100 nm and expressing CD63 and CD81 surface markers. These hMSC-derived exosomes were efficiently internalized by HUVECs, promoting their migration and differentiation. In addition, they selectively released a panel of miRNAs directly or indirectly related to angiogenesis. (4) Conclusions: Preconditioning of hMSCs on TNs induced elevated exosomes secretion that stimulated in vitro endothelial and cell activity, which might improve in vivo angiogenesis, supporting faster scaffold integration.

The Effects of Three Chlorhexidine-Based Mouthwashes on Human Osteoblast-Like SaOS-2 Cells. An In Vitro Study

Several decontamination methods for removing biofilm from implant surfaces during surgical peri-implantitis treatment have been reported, including the intraoperative usage of chlorhexidine (CHX)-based antiseptics. There is a lack of information on possible adverse effects on bone healing. The study aimed to examine the impact of three CHX-based mouthwashes on osteoblast-like cells (SaOS-2) in vitro. Cells were cultured for three days in 96-well binding plates. Each well was randomly treated for either 30, 60 or 120 s with 0.05% CHX combined with 0.05% cetylpyridinium chloride (CPC), 0.1% CHX, 0.2% CHX or sterile saline (NaCl) as control. Cell viability, cytotoxicity and apoptosis were assessed at day 0, 3 and 6. Cell viability resulted in being higher in the control group at all time points. At day 0, the CHX 0.2 group showed significantly higher cytotoxicity values compared to CHX 0.1 (30 s), CHX + CPC (30 s, 60 s and 120 s) and control (60 s and 120 s), while no significant differences were identified between CHX + CPC and both CHX 0.1 and NaCl groups. All test mouthwashes were found to induce apoptosis to a lower extent compared to control. Results indicate that 0.2% CHX presented the highest cytotoxic effect. Therefore, its intraoperative use should be carefully considered.

Bone remodelling patterns around orthodontic mini-implants migrating in bone: an experimental study in rat vertebrae

Background

Orthodontic implant migration has been clinically observed in presence of continuous loading forces. Recent studies indicate that osteocytes play a crucial role in this phenomenon.

Objectives

Aim of this study was to investigate local osteocytic gene expression, protein expression, and bone micro-structure in peri-implant regions of pressure and tension.

Material and methods

The present work reports a complementary analysis to a previous micro-computed tomography study. Two customized mini-implants were placed in one caudal rat vertebra and connected by a nickel–titanium contraction spring generating different forces (i.e. 0, 0.5, 1.0, and 1.5 N). Either at 2 or 8 weeks, the vertebrae were harvested and utilized for 1. osteocytic gene expression using laser capture micro-dissection on frozen sections coupled with qPCR, 2. haematoxylin–eosin staining for qualitative and quantitative analyses, 3. immunofluorescence staining and analysis, and 4. bone-to-implant contact on undecalcified samples.

Results

At the two time points for all the performed analyses no significant differences were observed with respect to the applied force magnitudes and cell harvesting localization. However, descriptive histological analysis revealed remarkable bone remodelling at 2 weeks of loading. At 8 weeks the implants were osseointegrated and, especially in 1.0 and 1.5 N groups, newly formed bone presented a characteristic load bearing architecture with trabecula oriented in the direction of the loading.

Conclusions

The present study confirmed that stress-induced bone remodelling is the biological mechanism of orthodontic implant migration. Bone apposition was found at ‘tension’ and ‘pressure’ sites thus limiting implant migration over time.

Summary of European guidelines on infection control and prevention during COVID-19 pandemic

Objectives

The current COVID‐19 pandemic highlighted the need for a review of guidelines on infection control and prevention to ensure safe delivery of dental care. However, it is not clear to what extent the rapidly published European guidelines reflect the current evidence and thus provide homogeneous recommendations.

Material & Methods

Guidelines from all European Union countries, Scotland, Switzerland and United Kingdom were retrieved. Information on triage, mouth rinse, personal protective equipment (PPE) for aerosol free/ generating procedures (non‐AGP/AGP) and treatment of potentially infectious patients were summarized and compared with recommendations from international organizations (WHO, ECDC, CDC).

Results

All included countries (30/30) published COVID‐19 guidelines in 2020. All countries recommended triage and to postpone non‐urgent treatment of potentially infectious patients. Hydrogen peroxide (1%–1.5%) was the most frequently recommended antiseptic mouth rinse to reduce viral load (24/30). PPE for non‐AGP treatments included mainly surgical masks (21/30) or FFP2/FFP3/N95 masks (16/30), whereas FFP2/FFP3 masks (25/30) and face shields (24/30) were recommended for AGP by the vast majority of guidelines. For high‐risk/COVID positive patients, most countries recommended maximum protection and treatment in specialized dental clinics (22/30).

Conclusion

There was general agreement among recommendations for triage, mouth rinse, and PPE during AGP and treatment of potentially infectious patients. In contrast, recommendations on PPE for non‐AGP treatment varied considerably among the European countries possibly due to limited scientific evidence regarding transmission risk during non‐AGP treatments.

Dental care during COVID-19 pandemic: follow-up survey of experts' opinion

Objectives

The purpose of the present survey is to give an update of European experts' opinion on infection control and prevention in dentistry during second wave of pandemic. The secondary aim was to analyze how experts' opinion changed in the light of the new scientific evidence since the first wave.

Material & Methods

An anonymous online 14‐item questionnaire was sent to a total of 27 leading academic experts in Oral (and Maxillofacial) Surgery from different European countries, who had completed a previous survey in April‐May 2020. The questionnaire covered the topics of dental setting safety, personal protective equipment (PPE), and patient‐related measures to minimize transmission risk. Data collection took place in November‐February 2020/21.

Results

26 experts participated in the follow‐up survey. The overall transmission risk in dental settings was scored significantly lower compared to the initial survey (p < .05), though the risk associated with aerosol‐generating procedures (AGP) was still considered to be high. Maximum PPE was less frequently recommended for non‐AGP (p < .05), whereas the majority of experts still recommended FFP2/FFP3 masks (80.8%), face shields or goggles (88.5%), gowns (61.5%), and caps (57.7%) for AGP. Most of the experts also found mouth rinse relevant (73.1%) and reported to be using it prior to treatment (76.9%). No uniform opinion was found regarding the relevance of COVID‐19 testing of staff and patients.

Conclusion

With the continuation of dental care provision, transmission risk has been scored lower compared to the first wave of pandemic. However, high risk is still assumed for AGP, and maximum PPE remained advised for the respective treatments.

COVID-19: Review of European recommendations and experts' opinion on dental care. Summary and consensus statements of group 5. The 6th EAO Consensus Conference 2021

Objectives

The present work reports the EAO workshop group 5 and consensus plenary discussions and statements based on two reviews summarising European guidelines and experts’ opinion on infection control and prevention (ICP) in dentistry during the pandemic.

Material

Two manuscripts were presented at the 6th EAO Consensus Conference. The first study compared the most recent national guidelines/recommendations of European countries. The second paper was an experts’ opinion‐based survey on application of ICP regulation during the second wave. The outcome of COVID‐19 group discussion was presented to all participants of the consensus to come to an agreement about the consensus statements and clinical recommendation.

Results

The dynamic of the pandemic had an impact on rapidly published and frequently updated national guidelines in Europe. As guidelines were not based on solid evidence, they were supplemented by experts’ opinion on ICP in dentistry. The dental care should be guaranteed during the pandemic; however, in case of suspected or confirmed COVID‐19 disease, the treatment should be postponed if possible. Remote triage and patient‐related measures (i.e., social distancing, hand hygiene and mask wearing) were recommended to be the most efficient to reduce SARS‐CoV‐2 transmission. The type of personal protective equipment for dental staff should be adequate to the procedure and infection risk.

Conclusions

Adequate infection control protocols have to be followed by healthcare professionals and patients to minimise the spreading of COVID‐19. We foresee the importance of continuously updating the national dental guidelines, considering the evolution of the pandemic and new scientific evidence becoming available.

Efficacy of 0.05% Chlorhexidine and 0.05% Cetylpyridinium Chloride Mouthwash to Eliminate Living Bacteria on In Situ Collected Biofilms: An In Vitro Study

Chlorhexidine (CHX) mouthwashes are frequently used as an adjunctive measure for the treatment of periodontitis and peri-implantitis, as well as in patients on maintenance therapy. However, their prolonged use is associated with several side effects. This study aimed at evaluating if a mouthwash with a reduced concentration of CHX combined with cetylpyridnium chloride (CPC) was as effective as a conventional CHX mouthwash in the reduction in living cells in oral biofilms attached to hydroxyapatite (HA) and micro-rough titanium (Ti) surfaces. Four healthy volunteers wore a customized acrylic appliance containing HA and Ti discs for in situ plaque accumulation. Biofilms were grown on the discs for 24 or 48 h and then randomly exposed for 60 s to: 0.05% CHX + 0.05% CPC, 0.1% CHX (positive control) or sterile saline (negative control). Viability assay and live-dead staining were performed to quantify bacterial viability and to distinguish live and dead cells, respectively. At both time points, contrary to saline, CHX, both alone and in combination with CPC, exhibited high antibacterial properties and induced a significant reduction in biofilm viability. This study demonstrates the potential of mouthwashes containing a low concentration of CHX combined with CPC as effective antibacterial agents for long-term applications with reduced undesired side effects.

Electrospun PCL-Based Vascular Grafts: In Vitro Tests

BACKGROUND

Electrospun fibers have attracted a lot of attention from researchers due to their several characteristics, such as a very thin diameter, three-dimensional topography, large surface area, flexible surface, good mechanical characteristics, suitable for widespread applications. Indeed, electro-spinning offers many benefits, such as great surface-to-volume ratio, adjustable porosity, and the ability of imitating the tissue extra-cellular matrix.

METHODS

we processed Poly ε-caprolactone (PCL) via electrospinning for the production of bilayered tubular scaffolds for vascular tissue engineering application. Endothelial cells and fibroblasts were seeded into the two side of the scaffolds: endothelial cells onto the inner side composed of PCL/Gelatin fibers able to mimic the inner surface of the vessels, and fibroblasts onto the outer side only exposing PCL fibers. Extracellular matrix production and organization has been performed by means of classical immunofluorescence against collagen type I fibers, Scanning Electron-Microscopy (SEM) has been performed in order to evaluated ultrastructural morphology, gene expression by means gene expression has been performed to evaluate the phenotype of endothelial cells and fibroblasts.

RESULTS AND CONCLUSION

results confirmed that both cells population are able to conserve their phenotype colonizing the surface supporting the hypothesis that PCL scaffolds based on electrospun fibers should be a good candidate for vascular surgery.

Implantoplasty: Carbide burs vs diamond sonic tips. An in vitro study

OBJECTIVES

Implantoplasty (IP) is a treatment option for peri-implantitis. Mechanical concerns were raised on fracture resistance of implants subjected to this procedure. This study aimed to compare two methods of IP in terms of implant wear and fracture resistance, and of surface topography.

MATERIAL AND METHODS

Eighteen cylindrical screw-shaped dental implants (4 mm diameter, 13 mm length) with an external hexagonal connection were used. IP was performed on the first 6-mm implant surface with a sequence of burs or diamond sonic tips, both followed by an Arkansas finishing. IP duration and implant weight variation were recorded. Micro-computed tomography (micro-CT) was used to evaluate material loss. Implant fracture resistance was assessed by static compression test. Surface topography analysis was performed with a stylus profilometer. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) was applied for implant surface morphology and elemental characterization.

RESULTS

Micro-CT showed less material loss in sonic compared to burs. No statistically significant difference was found between the mean fracture resistance values reached in bur and sonic, both followed by Arkansas, and with respect to control. IP performed with burs led to a smoother surface compared to sonic. Equivalent final surface roughness was found after Arkansas in both IP procedures. SEM-EDS showed a deburring effect associated to sonic and revealed carbon and aluminum peaks attributable to contamination with sonic diamond tips and Arkansas bur, respectively.

CONCLUSIONS

IP with sonic diamond tips was found to be more conservative in terms of structure loss. This could have a clinical relevance in case of narrow-diameter implants.

Dental care during COVID-19 pandemic: Survey of experts' opinion

Objectives

The current COVID‐19 outbreak in conjunction with the need to provide safe dental treatments and the limited knowledge on the efficacy of protective measures has posed dentists into a challenging situation. Therefore, the present article aimed at collecting experiences and recommendations of frontline clinical experts on critical aspects of dental treatment provision during pandemic.

Material & Methods

From a total of 32 European countries, one leading academic expert in Oral and Maxillofacial Surgery or Oral Surgery per country was asked to participate in an anonymous online 10‐item survey on COVID‐19 covering the topics of safety of dental settings, personal protective equipment (PPE), and patient‐related measures to reduce transmission risk. Data collection took place from April 12th to May 22nd, 2020.

Results

A total of 27 experts from different European countries completed the survey. The transmission risk of SARS‐CoV‐2 in dental settings for aerosol‐generating procedures was considered high by all experts except two. For aerosol‐free and aerosol‐generating procedures, more than 80% of the experts recommended face protection and caps for every single treatment. For aerosol‐generating procedures, additional measures (FFP2/FFP3 masks and gowns) were suggested by the vast majority of the experts. To reduce transmission risk, all experts recommended limiting aerosol‐generating procedures and reducing the number of patients in waiting areas as well as hand hygiene for the patients.

Conclusion

The limitation of aerosol‐generating procedures along with the usage of adequate personal protection equipment was considered to be crucial to protect dental healthcare providers and patients, thus reducing the transmission risk of COVID‐19.

Automatic Digital Design of the Occlusal Anatomy of Monolithic Zirconia Crowns Compared to Dental Technicians' Digital Waxing: A Controlled Clinical Trial

PURPOSE

Reconstructing the occlusal morphology of posterior teeth in definitive dental prosthesis can be challenging. The use of the correlation technique enables replication of the information and occlusal anatomy of interim dental prostheses to the definitive ones. The purpose of this controlled clinical trial was to compare the static and dynamic contacts (SDC) of monolithic zirconia crowns designed with correlation and library techniques.

MATERIAL AND METHODS

Twenty-four patients were included in the study for a total of 28 molars. For each abutment tooth, an interim crown was fabricated and two digital scans, with and without the interim crown in place were made. Two single crowns were designed using correlation and library techniques. Fifty-six monolithic zirconia crowns were milled. The interim and definitive crowns were evaluated intraorally for SDC by using a 24-μm-thick blue articulating foil. After removing the interim and definite crowns, extraoral photographs were taken to calculate the SDC area using software (ImageJ) and analyzed by the Kruskal-Wallis test.

RESULTS

The average and ± standard deviation (SD) of area of the occlusal marks on interim crowns was 32.27 ± 3.45 mm² . Definitive crowns designed by using the correlation technique had an area of 31.01 ± 3.73 mm² ; the area in the library technique was 36.85 ± 5.78 mm² . No statistically significant difference was found (p = 0.091) between the occlusal mark areas of the interim and definitive crowns designed by using the correlation technique. Whereas, there were significant differences between the areas of occlusal marks of the interim and definitive crowns designed by using the library technique, and between the areas of occlusal marks of definitive crowns designed by using the correlation and library techniques (p < 0.001).

CONCLUSION

The average area of the SDC of monolithic zirconia crowns designed by using the correlation technique was similar to that of interim crowns. The library technique was less effective when replicating the SDC compared to the correlation technique.

Recommendations for Dental Care during COVID-19 Pandemic

Dental clinics were suspected to be a hotspot for nosocomial transmission of coronavirus disease 19 (COVID-19), yet there has been no clear recommendation about emergency dental care and appropriate personal protective equipment during pandemics. In this paper, we aim to summarize recommendations for (i) patient risk assessment, (ii) patient triage, and (iii) measures to prevent infection of health professionals and nosocomial transmission in dental clinics. The available evidence was collected by performing searches on PubMed, Embase, and Cochrane databases. We reviewed papers on COVID-19, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), influenza, and related respiratory viral diseases. Legal and ethical frameworks, as well as international (e.g., World Health Organization (WHO)) and national (e.g., public health institutes, dental associations) guidelines were screened to summarize recommendations related to dental emergency care. To assess the patient risk, a questionnaire was developed to classify patients at unknown, high, and very high risk. Patient triage recommendations were summarized in a flow chart that graded the emergency level of treatments (i.e., urgent, as soon as possible, and postpone). Measures to prevent disease transmission based on current evidence were grouped for dental health professionals, dental clinics, and patients. The present recommendations may support health professionals implement preventative measures during the pandemic.

Bioactive Glass and Silicate-Based Ceramic Coatings on Metallic Implants: Open Challenge or Outdated Topic?

The overall success and long-term life of the medical implants are decisively based on the convenient osseointegration at the hosting tissue-implant interface. Therefore, various surface modifications and different coating approaches have been utilized to the implants to enhance the bone formation and speed up the interaction with the surrounding hosting tissues, thereby enabling the successful fixation of implants. In this review, we will briefly present the main metallic implants and discuss their biocompatibility and osseointegration ability depending on their chemical and mechanical properties. In addition, as the main goal of this review, we explore the main properties of bioactive glasses and silica-based ceramics that are used as coating materials for both orthopedic and dental implants. The current review provides an overview of these bioactive coatings, with a particular emphasis on deposition methods, coating adhesion to the substrates and apatite formation ability tested by immersion in Simulated Body Fluid (SBF). In vitro and in vivo performances in terms of biocompatibility, biodegradability and improved osseointegration are examined as well.

Biocompatibility and antibacterial properties of zirconium nitride coating on titanium abutments: An in vitro study

Improving soft tissue attachment and reducing bacterial colonization on titanium abutments are key factors for the long-term maintenance of healthy soft and hard peri-implant tissues. This in vitro study was conducted to compare the biocompatibility and antibacterial activity of four different surfaces: uncoated Ti6Al4V, anodized, and coated with titanium nitride or zirconium nitride. Surface topography was investigated with a high-resolution system for measuring surface finishes. Human gingival fibroblast (HGF) adhesion and proliferation were examined using MTT assay, Scanning Electron Microscopy (SEM) imaging, immunofluorescence analysis and real-time PCR for selected target genes. The hemolysis and AMES tests were performed to assess the chemical compounds’ blood compatibility and mutagenic potential, respectively. Antibacterial activity was tested against five bacterial strains isolated from the oral cavity (Streptococcus salivarius, S. sanguinis, S. mutans, S. sobrinus, S. oralis), and the percentage of dead bacteria was calculated. Roughness measurements confirmed a substantial similarity between the surfaces and their compatibility with clinical applications. MTT assay, SEM analysis and immunofluorescence staining showed adhesion and proliferation of HGFs cultured on all the examined surfaces. PCR confirmed that HGFs produced extracellular matrix components efficiently on all the surfaces. No hemolytic activity was detected, and the AMES test confirmed the surfaces’ clinical safety. For all tested bacterial strains, biofilms grown on the zirconium nitride surface showed a higher percentage of dead bacteria than on the other disks. The titanium nitride surface inactivated bacterial biofilms, too, but to a lesser extent.

Novel Nanotechnologies for Brain Cancer Therapeutics and Imaging

Despite progress in surgery, radiotherapy, and in chemotherapy, an effective curative treatment of brain cancer, specifically malignant gliomas, does not yet exist. The efficacy of current anti-cancer strategies in brain tumors is limited by the lack of specific therapies against malignant cells. Besides, the delivery of the drugs to brain tumors is limited by the presence of the blood-brain barrier. Nanotechnology today offers a unique opportunity to develop more effective brain cancer imaging and therapeutics. In particular, the development of nanocarriers that can be conjugated with several functional molecules including tumor-specific ligands, anticancer drugs, and imaging probes, can provide new devices which are able to overcome the difficulties of the classical strategies. Nanotechnology-based approaches hold great promise for revolutionizing brain cancer medical treatments, imaging, and diagnosis.

A hyaluronan-based scaffold for the in vitro construction of dental pulp-like tissue

Dental pulp tissue supports the vitality of the tooth, but it is particularly vulnerable to external insults, such as mechanical trauma, chemical irritation or microbial invasion, which can lead to tissue necrosis. In the present work, we present an endodontic regeneration method based on the use of a tridimensional (3D) hyaluronan scaffold and human dental pulp stem cells (DPSCs) to produce a functional dental pulp-like tissue in vitro. An enriched population of DPSCs was seeded onto hyaluronan-based non-woven meshes in the presence of differentiation factors to induce the commitment of stem cells to neuronal, glial, endothelial and osteogenic phenotypes. In vitro experiments, among which were gene expression profiling and immunofluorescence (IF) staining, proved the commitment of DPSCs to the main components of dental pulp tissue. In particular, the hyaluronan-DPSCs construct showed a dental pulp-like morphology consisting of several specialized cells growing inside the hyaluronan fibers. Furthermore, these constructs were implanted into rat calvarial critical-size defects. Histological analyses and gene expression profiling performed on hyaluronan-DPSCs grafts showed the regeneration of osteodentin-like tissue. Altogether, these data suggest the regenerative potential of the hyaluronan-DPSC engineered tissue.

Nanostructured guidance for peripheral nerve injuries: a review with a perspective in the oral and maxillofacial area

Injury to peripheral nerves can occur as a result of various surgical procedures, including oral and maxillofacial surgery. In the case of nerve transaction, the gold standard treatment is the end-to-end reconnection of the two nerve stumps. When it cannot be performed, the actual strategies consist of the positioning of a nerve graft between the two stumps. Guided nerve regeneration using nano-structured scaffolds is a promising strategy to promote axon regeneration. Biodegradable electrospun conduits composed of aligned nanofibers is a new class of devices used to improve neurite extension and axon outgrowth. Self assembled peptide nanofibrous scaffolds (SAPNSs) demonstrated promising results in animal models for central nervous system injuries, and, more recently, for peripheral nerve injury. Aims of this work are (1) to review electrospun and self-assembled nanofibrous scaffolds use in vitro and in vivo for peripheral nerve regeneration; and (2) its application in peripheral nerve injuries treatment. The review focused on nanofibrous scaffolds with a diameter of less than approximately 250 nm. The conjugation in a nano scale of a natural bioactive factor with a resorbable synthetic or natural material may represent the best compromise providing both biological and mechanical cues for guided nerve regeneration. Injured peripheral nerves, such as trigeminal and facial, may benefit from these treatments.

[Steinert's myotonic dystrophy: severe neonatal form with unknown family history]

A child with severe generalized hypotonia and respiratory insufficiency, with an unknown positive family history for Steinert's disease, is referred. We want to point out the importance of correct anamnesis and of physical examination during pregnancy to suspect and diagnose rare and incurable fetal pathologies.

CASE REPORT

The child was born after caesarean section. Polyhydramnios and decreased fetal movements were noticed during pregnancy. At birth, the baby presented asphyxia (Apgar 4/6) and respiratory insufficiency: he was then intubed. He received assisted ventilation for 37 days. At the physical examination, the child appeared hypotonic, hyporeflexic, without sucking reflex, with arthrogryposis and ligament laxity. On first day, chest X-ray showed paralysis of the right hemidiaphragm. His mother presented with hypotonia of the facial muscles, lid drop, light muscular weakness, positivity to neostigmine test: we then assumed that the baby was affected by transient neonatal myasthenia gravis and neostigmine was carried on. Anyway, the general conditions of the baby didn't improve. We were able to establish diagnosis of Steinert's disease (a form of muscular dystrophy with autosomal dominant inheritance with incomplete penetrance) after some other examinations (negativity of acetylcholine receptor antibodies, elevation of creatine kinase level, myopathic pattern on electromyography). Gene DMPK alteration was documented with a molecular genetic test.