Scaffolds for Dentin-Pulp Complex Regeneration

Background and Objectives: Regenerative dentistry aims to regenerate the pulp-dentin complex and restore those of its functions that have become compromised by pulp injury and/or inflammation. Scaffold-based techniques are a regeneration strategy that replicate a biological environment by utilizing a suitable scaffold, which is considered crucial for the successful regeneration of dental pulp. The aim of the present review is to address the main characteristics of the different scaffolds, as well as their application in dentin-pulp complex regeneration. Materials and Methods: A narrative review was conducted by two independent reviewers to answer the research question: What type of scaffolds can be used in dentin-pulp complex regeneration? An electronic search of PubMed, EMBASE and Cochrane library databases was undertaken. Keywords including "pulp-dentin regeneration scaffold" and "pulp-dentin complex regeneration" were used. To locate additional reports, reference mining of the identified papers was undertaken. Results: A wide variety of biomaterials is already available for tissue engineering and can be broadly categorized into two groups: (i) natural, and (ii) synthetic, scaffolds. Natural scaffolds often contain bioactive molecules, growth factors, and signaling cues that can positively influence cell behavior. These signaling molecules can promote specific cellular responses, such as cell proliferation and differentiation, crucial for effective tissue regeneration. Synthetic scaffolds offer flexibility in design and can be tailored to meet specific requirements, such as size, shape, and mechanical properties. Moreover, they can be functionalized with bioactive molecules, growth factors, or signaling cues to enhance their biological properties and the manufacturing process can be standardized, ensuring consistent quality for widespread clinical use. Conclusions: There is still a lack of evidence to determine the optimal scaffold composition that meets the specific requirements and complexities needed for effectively promoting dental pulp tissue engineering and achieving successful clinical outcomes.

Type I Diabetes in Zebrafish Reduces Sperm Quality and Increases Insulin and Glucose Transporter Transcripts

Type I diabetes is a prominent human pathology with increasing incidence in the population; however, its cause is still unknown. This disease promotes detrimental effects on reproduction, such as lower sperm motility and DNA integrity. Hence, the investigation of the underlying mechanisms of this metabolic disturbance in reproduction and its transgenerational consequences is of the utmost importance. The zebrafish is a useful model for this research considering its high homology with human genes as well as its fast generation and regeneration abilities. Therefore, we aimed to investigate sperm quality and genes relevant to diabetes in the spermatozoa of Tg(ins:nfsb-mCherry) zebrafish, a model for type I diabetes. Diabetic Tg(ins:nfsb-mCherry) males showed significantly higher expression of transcripts for insulin a (insa) and glucose transporter (slc2a2) compared to controls. Sperm obtained from the same treatment group showed significantly lower sperm motility, plasma membrane viability, and DNA integrity compared to that from the control group. Upon sperm cryopreservation, sperm freezability was reduced, which could be a consequence of poor initial sperm quality. Altogether, the data showed similar detrimental effects related to type I diabetes in zebrafish spermatozoa at the cellular and molecular levels. Therefore, our study validates the zebrafish model for type I diabetes research in germ cells.

May carriers at nanoscale improve the Endodontic's future?

Nanocarriers (NCs) are dynamic nanovehicles used to transport bioactive derivatives like therapeutical formulations, drugs and/or dyes. The current review assists in understanding the mechanism of action of several recent developed NCs with antimicrobial purposes. Here, nine NCs varieties are portrayed with focus on nineteen approaches that are fulfil described based on outcomes obtained from in vitro antimicrobial assays. All approaches have previously been verified and we underline the biochemical challenges of all NCs, expecting that the present data may encourage the application of NCs in endodontic antimicrobial basic research. Methodological limitations and the evident base gaps made not possible to draw a definite conclusion about the best NCs for achieving efficient antimicrobial outcomes in endodontic studies. Due to the lack of pre-clinical trials and the scarce number of clinical trials in this emergent area, there is still much room for improvement on several fronts.

Outcome of selective root canal retreatment-A retrospective study

AIM

Selective root canal retreatment is when the treatment is limited to root(s) with radiographic evidence of periapical pathosis. The goals of this retrospective study were as follows: (i) evaluate the clinical and radiographic (periapical radiographs [PR] or cone-beam computerized tomographs [CBCT]) outcome of selective root canal retreatment after ≥12 months follow-up; (ii) evaluate the periapical status of the unretreated roots; and (iii) assess tooth survival.

METHODOLOGY

A retrospective study (January 2018 to April 2021) was conducted to identify permanent multirooted teeth that underwent selective root canal retreatment. Clinical records, PR and CBCT were examined to ascertain variables of interest. Outcomes (per root and per tooth) were classified into 'favourable' or 'unfavourable' using well-established clinical and radiographic healing criteria. Treatment outcomes for the whole tooth and per root were compared as well as bivariate associations between the treatment outcome of the retreated roots and the treatment-related parameters (quality of root filling, sealer extrusion, iatrogenic mishaps and type of restoration) were analysed using Fisher's exact test (α = .05). Survival was recorded in months.

RESULTS

A total of 75 teeth (195 roots) in 75 subjects were available for outcome analysis. The favourable outcome per tooth was 86.7%. At follow-up, 92.6% of the retreated roots had a favourable outcome. From the unretreated roots, 3.5% showed radiographic signs of an emerging periapical lesion. No statistical difference was shown between the outcomes per root and per tooth between both groups. None of the treatment-related parameters had a direct influence on the outcome of the retreated roots. The survival rate at 12-48 months after retreatment was 91.5%.

CONCLUSIONS

Selective root canal retreatment is associated with a favourable outcome in a majority of cases. Unretreated roots rarely developed radiographic signs of a new periapical lesion at follow-up. Future high-quality clinical trials with larger sample sizes and longer follow-up periods are required to confirm these findings.

Health behaviours as predictors of the Mediterranean diet adherence: a decision tree approach

OBJECTIVE

This study aimed to identify health behaviours that determine adolescent's adherence to the Mediterranean diet (MD) through a decision tree statistical approach.

DESIGN

Cross-sectional study, with data collected through a self-fulfilment questionnaire with five sections: (1) eating habits; (2) adherence to the MD (KIDMED index); (3) physical activity; (4) health habits and (5) socio-demographic characteristics. Anthropometric and blood pressure data were collected by a trained research team. The Automatic Chi-square Interaction Detection (CHAID) method was used to identify health behaviours that contribute to a better adherence to the MD.

SETTING

Eight public secondary schools, in Algarve, Portugal.

PARTICIPANTS

Adolescents with ages between 15 and 19 years (n 325).

RESULTS

According to the KIDMED index, we found a low adherence to MD in 9·0 % of the participants, an intermediate adherence in 45·5 % and a high adherence in 45·5 %. Participants that regularly have breakfast, eat vegetable soup, have a second piece of fruit/d, eat fresh or cooked vegetables 1 or more times a day, eat oleaginous fruits at least 2 to 3 times a week, and practice sports and leisure physical activities outside school show higher adherence to the MD (P < 0·001).

CONCLUSIONS

The daily intake of two pieces of fruit and vegetables proved to be a determinant health behaviour for high adherence to MD. Strategies to promote the intake of these foods among adolescents must be developed and implemented.

Influence of Preoperative Pulp Inflammation in the Outcome of Full Pulpotomy Using a Dog Model

INTRODUCTION

This study aimed to evaluate the impact of preoperative pulp inflammation on the histologic outcome of full pulpotomy performed in mature permanent posterior teeth using 4 different biomaterials.

METHODS

Five beagle dogs (providing a total of 120 roots) were selected. Dentin exposure was performed in teeth from the second and third quadrants. One week later, full pulpotomy procedures were performed using 4 different bioactive materials (ProRoot MTA [MTA], TotalFill BC Putty [BC], Biodentine [BIO], and an experimental cement [ie, pulp capping material]). The hemostasis time was registered. After 14 weeks, the animals were killed. Pulp-dentin tissues were histologically and radiographically assessed. The significance level was set at .05.

RESULTS

Teeth with previously exposed dentin revealed a statistically significant increase in the time required to achieve hemostasis (P < .001), therefore confirming the pulp inflammation status induced by 1-week exposure of occlusal dentin before performing full pulpotomy. There was no radiographic evidence of root resorption, periapical radiolucency, or lamina dura alterations. No statistically significant differences were observed between normal and inflamed pulp regardless of the evaluated histologic parameters. Moreover, histologic data concerning calcified barrier formation and the pulp tissue response show better results for BIO without statistical differences compared with MTA or BC (P > .05). The pulp capping material presented a lower performance, with statistically significant differences being detected in regard to the remaining 3 tested materials (P < .001).

CONCLUSIONS

Radiographic and histologic outcomes of full pulpotomy are not jeopardized by short-term preoperative pulp inflammation. Moreover, BIO, MTA, and BC cements present suitable alternatives to be used as pulp capping agents.

Coronary artery fistulas: a single-center case series

Introduction

Coronary artery fistulas (CAFs) are rare anomalous connections between a coronary artery and a major vessel or cardiac chamber. Currently they are being increasingly encountered due to the more widespread use of various imaging modalities and coronary angiography. Although the vast majority of CAFs are incidentally diagnosed and have no clinical relevance, they can cause significant morbidity such as myocardial infarction, congestive heart failure and endocarditis.

Methods

A consecutive series of 55867 coronary arteriograms performed in our Cardiology Department from 2007 to 2019 was retrospectively investigated for the presence of coronary artery fistulas. Patients clinical, angiographic and therapeutic data up to november 2019 were analyzed. Data were obtained from medical records of hospital stay and subsequent consultations.

Results

We identified 50 patients who were diagnosed with one or more CAFs, with ages between 5 and 85 years (mean 59 years). 62% (n=31) were males.

The great majority of patients had a single fistula (n=34, 68%), 11 patients had two fistulas (22%), 1 patient had 3 fistulas (2%) and 4 patients had multiple fistulas (8%).

CAFs arose more frequently from the left anterior descending artery (n=27), followed by the right coronary (n=18), left circumflex (n=15), left main (n=5) and intermediate artery (n=2). The most frequent drainage site was the pulmonary artery (n=38).

The majority of CAFs were incidentally found (n=32; 64%) and thought to have no significance for the patients' clinical status. As for the rest of the patients, CAFs were diagnosed during evaluation of: a heart murmur (n=7); exertional chest pain with no associated significant atherosclerotic coronary artery disease (n=7); exertional dyspnea (n=2); positive exercise stress test (n=1); NSTEMI and cardiac arrest (n=1).

Regarding treatment, watchful waiting was the main approach (n=40; 80%). 3 patients had their CAFs closed during surgery for another heart condition (CABG/aortic valve replacement). In 1 patient, heart surgery was specifically conducted for fistula closure. 6 patients (12%) underwent fistula transcatheter closure.

Conclusion

CAFs are rare coronary anomalies and the majority has no clinical relevance, so watchful waiting is the commonest approach. When they are hemodynamically significant or symptoms/complications arise, surgical or transcatheter closure should be considered. This study describes the angiographic, clinical and therapeutic data of CAFs detected along the last 12 years in a single tertiary care center catheterization laboratory.

Funding Acknowledgement

Type of funding source: None

P1310 Prosthetic valve endocarditis or thrombus?

One cause of constitutional syndrome in patients previously submitted to valve replacement surgery is a prosthetic endocarditis; this occurs in 1-6% of valve surgeries and has an adverse prognosis. Although this is a likely etiology, it is important to keep other possibilities in mind. This clinical case is about a 61 years old male, with known history of smoking, atrial fibrillation anticoagulated with warfarin (with low TTR), and rheumatic fever in childhood, with severe aortic stenosis/regurgitation and moderate mitral regurgitation. In August 2018 he was admitted in our hospital with mitral valve endocarditis cause by Streptococcus agalactiae. He was submitted to an aortic and mitral valve replacement surgery with 2 bioprothesis. Three months later he was admitted again with weight loss, fatigue, dyspnea for small efforts and worsening anemia. The first diagnosis hypothesis was prosthetic endocarditis. The echocardiogram showed normo-functioning aortic bioprothesis; obstructive mitral bioprothesis with an image suggestive of a vegetation; and a de novo mass in the left auricle, compatible with a thrombus. This clinical case was discussed in Heart Team: as the patient was clinically stable, it was opted for an initial conservative approach; although there was a strong clinical suspicion that all the clinical case was due to thrombotic manifestations (assuming that the vegetations had a non-infectious origin), he was nonetheless medicated with vancomycin, gentamicin and rifampicin, as the diagnosis of early culture negative prosthetic endocarditis could not be discarded. He was anticoagulated with enoxaparin. In the reevaluation echocardiogram there was a significative reduction of the left atrial thrombus and disappearance of the mitral valve vegetation image, with improvement of the mitral valve prosthetic gradients. The case was discussed again in Heart Team: due to the clinical evolution, the hypothesis that this was all caused by a thrombotic manifestation grew stronger; it was opted not to submit the patient to a new surgery and the antibiotic therapy was suspended. To study the pro-thrombotic state and the constitutional syndrome, a full body CT was requested: "hilar-mediastinal and bilateral hilar adenopathy; right supraclavicular adenopathy; splenomegaly with infarcted area." The right hilar adenopathy was biopsied; the pathologic exam revealed non-small cells lung carcinoma. The patient was discharged, medicated with warfarin and oriented to outpatient Oncology consult. Any cancer can be associated with thrombotic manifestations. In this case, considering the heavy smoking burden, lung cancer is one of the first etiologies to consider. The thrombotic manifestations of the non-small cells lung carcinoma are due to a paraneoplastic mechanism and might precede the cancer diagnosis. This clinical case highlights the importance of thinking of different etiologies in the differential diagnosis of a constitutional syndrome.

Abstract P1310 Figure. Left auricle mass

Microdiet Formulation with Phospholipid Modulate Zebrafish Skeletal Development and Reproduction

Dietary phospholipids' (PLs) content, origin, and profile are known to affect fish development and reproductive performance, but their effects in zebrafish (Danio rerio) nutrition are still poorly investigated. Therefore, this study aimed to assess the effect of practical microdiets containing plant-based and marine PL sources in zebrafish growth, survival, skeletal development, and reproductive performance. Reproductive performance was evaluated according to sperm motility, number of eggs, egg morphometry, hatching rate, and offspring standard length at 5 days postfertilization (dpf). For this purpose, seven microdiets were used, where two control diets were tested along with a supplementation with soybean lecithin (SL) as a plant-based PL source, and krill oil (KO) and copepod oil (CO) as marine PL sources, or in combinations (SLCO and SLKO). KO supplementation decreased larval growth performance and induced severe skeletal anomalies. SL supplementation reduced sperm total motility but improved offspring length at 5 dpf. CO supplementation increased sperm motility and the number of spawned eggs. Our results showed that a careful selection of the origin of dietary PL sources for microdiet formulation is critical to ensure adequate skeletal development and reproductive success. This study contributes to the improvement of zebrafish microdiet formulation and optimization of zebrafish husbandry practices.

An Insight into Advanced Approaches for Photosensitizer Optimization in Endodontics-A Critical Review

Apical periodontitis is a biofilm-mediated disease; therefore, an antimicrobial approach is essential to cure or prevent its development. In the quest for efficient strategies to achieve this objective, antimicrobial photodynamic therapy (aPDT) has emerged as an alternative to classical endodontic irrigation solutions and antibiotics. The aim of the present critical review is to summarize the available evidence on photosensitizers (PSs) which has been confirmed in numerous studies from diverse areas combined with several antimicrobial strategies, as well as emerging options in order to optimize their properties and effects that might be translational and useful in the near future in basic endodontic research. Published data notably support the need for continuing the search for an ideal endodontic photosensitizer, that is, one which acts as an excellent antimicrobial agent without causing toxicity to the human host cells or presenting the risk of tooth discoloration. The current literature on experimental studies mainly relies on assessment of mixed disinfection protocols, combining approaches which are already available with aPDT as an adjunct therapy. In this review, several approaches concerning aPDT efficiency are appraised, such as the use of bacteriophages, biopolymers, drug and light delivery systems, efflux pump inhibitors, negative pressure systems, and peptides. The authors also analyzed their combination with other approaches for aPDT improvement, such as sonodynamic therapy. All of the aforementioned techniques have already been tested, and we highlight the biological challenges of each formulation, predicting that the collected information may encourage the development of other effective photoactive materials, in addition to being useful in endodontic basic research. Moreover, special attention is dedicated to studies on detailed conditions, aPDT features with a focus on PS enhancer strategies, and the respective final antimicrobial outcomes. From all the mentioned approaches, the two which are most widely discussed and which show the most promising outcomes for endodontic purposes are drug delivery systems (with strong development in nanoparticles) and PS solubilizers.

Selection Criteria of Zebrafish Male Donors for Sperm Cryopreservation

Selection criteria for sperm cryopreservation are highly relevant in zebrafish since sperm quality is particularly variable in this species. Successful cryopreservation depends on high-quality sperm, which can only be ensured by the selection of breeders. Consequently, male selection and management are a priority to improve cryopreservation, and therefore, this study aimed to characterize optimal age and sperm collection frequency in zebrafish. For this purpose, males from wild type (AB) and from a transgenic line [Tg(runx2:eGFP)] were sampled at 6, 8, 12, and 14 months. For each age, sperm were collected at time 0 followed by samplings at 2, 7, and 14 days of rest. Sperm quality was assessed according to motility and membrane viability parameters. Quality assessment showed that Tg(runx2:eGFP) displayed significantly higher motility than AB and younger males showed higher motility in both lines. Sperm collection frequency affected membrane viability. While AB fish recovered sperm viability after 14 days of rest, Tg(runx2:eGFP) could not recover. Consequently, it may be important to study the sperm quality of each zebrafish line before sperm cryopreservation. Taking into consideration the results achieved in both lines, sperm collection should be performed between 6 and 8 months of age with a minimum collection interval of 14 days.

Electric ultrafreezer (- 150 °C) as an alternative for zebrafish sperm cryopreservation and storage

Zebrafish sperm cryopreservation is a fundamental methodology to manage and back-up valuable genetic resources like transgenic and mutant strains. Cryopreservation usually requires liquid nitrogen for storage, which is expensive and hazardous. Our objective was to evaluate if electric ultrafreezers (- 150 °C) are a viable alternative for zebrafish sperm storage. Zebrafish sperm was cryopreserved in the same conditions (- 20 °C/min), stored either in liquid nitrogen or in an ultrafreezer, and thawed after 1 week, 1 month, and 3 months. Sperm motility, membrane integrity, and fertilization ability were assessed. There were no significant differences in motility and hatching rate throughout storage time. Additionally, we aimed at understanding if cryopreservation directly in an ultrafreezer (- 66 °C/min) could improve post-thaw sperm quality. Freezing at - 20 °C/min was performed as before, and compared to samples cryopreserved with a fast cooling rate by placing directly in an ultrafreezer (- 66 °C/min). Sperm quality was assessed according to motility, viability, DNA fragmentation, and apoptosis (annexin V). The - 66 °C/min cooling rate showed significantly higher membrane and DNA integrity, and lower number of cells in late apoptosis in comparison to the other treatments. This study showed that zebrafish sperm cryopreservation and storage in an ultrafreezer system is possible and a fast cooling rate directly in ultrafreezer improves post-thaw sperm quality.

Antimicrobial Photodynamic Therapy against Endodontic Enterococcus faecalis and Candida albicans Mono and Mixed Biofilms in the Presence of Photosensitizers: A Comparative Study with Classical Endodontic Irrigants

Endodontic biofilms eradication from the infected root canal system remains as the primary focus in endodontic field. In this study, it was assessed the efficacy of antimicrobial Photodynamic Therapy (aPDT) with the Zn(II)chlorin e6 methyl ester (Zn(II)e₆Me) activated by red light against monospecies and mixed biofilms of Enterococcus faecalis and Candida albicans. The results were compared with the ones obtained with Rose Bengal (RB), Toluidine Blue-O (TBO), the synthetic tetracationic porphyrin (TMPyP) as well as classical endodontic irrigants (3% NaOCl, 17% EDTA and 2% CHX). The antimicrobial efficacy of aPDT toward monospecies and mixed biofilms was quantified resorting to safranin red method. The changes of biofilm organization and of cellular ultrastructure were evaluated through several microscopy techniques (light, laser confocal and transmission electron microscopy). Zn(II)e₆Me once activated with light for 60 or 90 s was able to remove around 60% of the biofilm’s biomass. It was more efficient than TBO and RB and showed similar efficiency to TMPyP and classical irrigants, CHX and EDTA. As desirable in a PS, Zn(II)e₆Me in the dark showed smaller activity than TMPyP. Only NaOCl revealed higher efficiency, with 70–90% of the biofilm’s biomass removal. The organization of biofilms and the normal microbial cell ultrastructure were extensively damaged by the presence of Zn(II)e₆Me. aPDT with Zn(II)e₆Me showed to be an efficient antimicrobial strategy deserving further studies leading to a future clinical usage in endodontic disinfection.

Sea bass sperm freezability is influenced by motility variables and membrane lipid composition but not by membrane integrity and lipid peroxidation

Cryopreserved sperm quality depends on the characteristics of fresh sperm. Thus, it is necessary to establish a group of variables to predict the cryopreservation potential of the fresh samples with the aim of optimizing resources. Motility, viability, lipid peroxidation and lipid profile of European sea bass (Dicentrarchus labrax) sperm were determined before and after cryopreservation to establish which variables more accurately predict the sperm cryopreservation potential in this species. Cryopreservation compromised sperm quality, expressed as a reduction of motility (46.5 ± 2.0% to 35.3 ± 2.5%; P<0.01) and viability (91.3 ± 0.7% to 69.9 ± 1.6%; P<0.01), and produced an increase in lipid peroxidation (2.4 ± 0.4 to 4.0 ± 0.4 μmoles MDA/mill spz; P<0.01). Also, significant changes were observed in the lipid composition before and after freezing, resulting in a reduction in the cholesterol/phospholipids ratio (1.4 ± 0.1 to 1.1 ± 0.0; P<0.01), phosphatidylcholine (47.7 ± 0.8% to 44.2 ± 0.8%; P<0.01) and oleic acid (8.7 ± 0.2% to 8.3 ± 0.2%; P<0.05) in cryopreserved sperm, as well as an increase in lysophosphatidylcholine (4.4 ± 0.3% to 4.8 ± 0.3%; P<0.01) and C24:1n9 fatty acid (0.5 ± 0.1% to 0.6 ± 0.1%; P<0.05). Motility, velocity, cholesterol/phospholipids ratio, monounsaturated fatty acids and the n3/n6 ratio were positively correlated (P<0.05) before and after freezing, whereas, viability and lipid peroxidation were not correlated. Motility and the cholesterol/phospholipids (CHO/PL) ratio were negatively correlated (P<0.05) with each other and the CHO/PL ratio was positively correlated (P<0.05) with lipid peroxidation. Therefore, the results demonstrated that motility and plasma membrane lipid composition (CHO/PL) were the most desirable variables determined in fresh samples to predict cryo-resistance in European sea bass sperm, taking into account the effect of both on cryopreserved sperm quality.