A Systematic Review on Organ-on-a-Chip in PDMS or Hydrogel in Dentistry: An Update of the Literature.

Organs-on-a-chip (OoCs) are microfluidic devices constituted by PDMS or hydrogel in which different layers of cells are separated by a semipermeable membrane. This technology can set many parameters, like fluid shear stress, chemical concentration gradient, tissue-organ interface, and cell interaction. The use of these devices in medical research permits the investigation of cell patterning, tissue-material interface, and organ-organ interaction, mimicking the complex structures and microenvironment of human and animal bodies. This technology allows us to reconstitute in vitro complex conditions that recapitulate in vivo environments. One of the main advantages of these systems is that they represent a very realistic model that, in many cases, can replace animal experimentation, eliminating costs and related ethical issues. Organ-on-a-chip can also contain bacteria or cancer cells. This technology could be beneficial in dentistry for testing novel antibacterial substances and biomaterials, performing studies on inflammatory disease, or planning preclinical studies. A significant number of publications and reviews have been published on this topic. Still, to our knowledge, they mainly focus on the materials used for fabrication and the different patterns of the chip applied to the experimentations. This review presents the most recent applications of organ-on-a-chip models in dentistry, starting from the reconstituted dental tissues to their clinical applications and future perspectives.

What Is the Impact of Antimicrobial Photodynamic Therapy on Oral Candidiasis? An In Vitro Study.

This study aimed to evaluate the ability of photodynamic therapy, based on the use of a gel containing 5% delta aminolaevulinic acid (ALAD) for 45' followed by irradiation with 630 nm LED (PDT) for 7', to eradicate Candida albicans strains without damaging the gingiva. C. albicans oral strains and gingival fibroblasts (hGFs) were used to achieve these goals. The potential antifungal effects on a clinical resistant C. albicans S5 strain were evaluated in terms of biofilm biomass, colony forming units (CFU/mL) count, cell viability by live/dead analysis, and fluidity membrane changes. Concerning the hGFs, viability assays, morphological analysis (optical, scanning electronic (SEM), and confocal laser scanning (CLSM) microscopes), and assays for reactive oxygen species (ROS) and collagen production were performed. ALAD-mediated aPDT (ALAD-aPDT) treatment showed significant anti-biofilm activity against C. albicans S5, as confirmed by a reduction in both the biofilm biomass and CFUs/mL. The cell viability was strongly affected by the treatment, while on the contrary, the fluidity of the membrane remained unchanged. The results for the hGFs showed an absence of cytotoxicity and no morphological differences in cells subjected to ALAD-aPDT expected for CLSM results that exhibited an increase in the thickening of actin filaments. ROS production was augmented only at 0 h and 3 h, while the collagen appeared enhanced 7 days after the treatment.

The Influence on Osseointegration of Immediate Functional Loading on Single Crowns: A Randomized, Double-Blind, Split Mouth Controlled Clinical Trial with Histomorphometric Evaluation.

PURPOSE: To evaluate the influence of immediate loading on osseointegration and bone density of implants installed in a healed alveolar bone crest and supporting single crowns. MATERIALS AND METHODS: Two solid titanium transmucosal mini-screws were inserted in the distal regions of the mandible in 14 patients. One mini-implant was immediately functionally loaded, whereas the other was left unloaded. After two months of healing, biopsies were retrieved and new bone, old bone, and total bone (new and old bone) were assessed. RESULTS: Histological examination was performed on biopsies This peer-reviewed, accepted manuscript will undergo final editing and production prior to print publication. from 12 patients (n=12). New bone-to-implant contact percentage (BIC%) was 40.3 ± 16.8 % and 55.1 ± 19.1 % (p=0.043) at the unloaded and loaded sites, respectively, while the total BIC% was 44.9 ± 17.0 % and 59.5 ± 18.8 %, respectively (p=0.034). The new bone density was 45.9 ± 11.6 % and 45.9 ± 16.7 % in the unloaded and loaded implants, respectively (p=0.622). CONCLUSIONS: Immediate loading positively affected bone apposition on the implant surface, while no effect on bone density was observed after 2 months of healing.

Alveolar Ridge Preservation Procedures Performed with a Freeze-Dried Bone Allograft: Clinical and Histologic Outcomes in a Case Series: Part II

INTRODUCTION: Tooth extractions can result in alveolar bone dimensional changes, necessitating additional bone grafting for implant placement. Alveolar Ridge Preservation (ARP) aims to counteract post-extraction changes. This study evaluates the bone regenerative properties of a freeze-dried bone allograft (FDBA) and the clinical outcomes of implants in grafted extraction sites. MATERIALS AND METHODS: This case series enrolled 33 patients undergoing single/multiple tooth extractions followed by ARP. Biopsies were harvested during implant placement for histologic and histomorphometric analysis. Clinical outcomes included marginal bone loss and Pink Esthetic Score (PES). RESULTS: 25 patients completed the study. FDBA augmented sockets exhibited new bone formation adjacent to graft particles. Implants (n=25) showed 100% survival and success rates at 1 and 2 years. PES improved significantly over time (p<.001), while marginal bone loss did not significantly differ at 1 and 2 years (p=.096). Specimens showed trabecular bone, residual FDBA particles, and marrow spaces. High magnification revealed immature bone and woven bone bridges around graft particles. No inflammatory cells were observed. CONCLUSIONS: The case series provides valuable insights into ARP performed with FDBA; implants were placed after 3 months of healing without any additional bone augmentation, the histologic outcomes were favorable, and implants were successful after a 2-year period of follow-up.

3D printed dental implants with a porous structure: The in vitro response of osteoblasts, fibroblasts, mesenchymal stem cells, and monocytes.

AIMS: The first aim of this study was to characterize the surface topography of a novel 3D-printed dental implant at the micro- and macro-level. Its second aim was to evaluate the osteogenic, angiogenic, and immunogenic responses of human oral osteoblasts (hOBs), gingival fibroblasts (hGFs), mesenchymal stem cells (hAD-MSCs), and monocytes to this novel implant surface. METHODS: A 3D-printed Ti-6Al-4 V implant was produced by selective laser melting and subjected to organic acid etching (TEST). It was then compared to a machined surface (CTRL). Its biological properties were evaluated via cell proliferation assays, morphological observations, gene expression analyses, mineralization assessments, and collagen quantifications. RESULTS: Scanning electron microscopy analysis showed that the TEST group was characterized by a highly interconnected porous architecture and a roughed surface. The morphological observations showed good adhesion of cells cultured on the TEST surface, with a significant increase in hOB growth. Similarly, the gene expression analysis showed significantly higher levels of osseointegration biomarkers. Picrosirius staining showed a slight increase in collagen production in the TEST group compared to the CTRL group. hAD-MSCs showed an increase in endothelial and osteogenic commitment-related markers. Monocytes showed increased mRNA synthesis related to the M2 (anti-inflammatory) macrophagic phenotype. CONCLUSIONS: Considering the higher interaction with hOBs, hGFs, hAD-MSCs, and monocytes, the prepared 3D-printed implant could be used for future clinical applications. CLINICAL RELEVANCE: This study demonstrated the excellent biological response of various cells to the porous surface of the novel 3D-printed implant.

Complex magnetic fields represent an eco-sustainable technology to counteract the resistant Candida albicans growth without affecting the human gingival fibroblasts.

Novel technologies such as complex magnetic fields-CMFs represent an eco-sustainable proposal to counteract the infection associated to resistant microorganisms. The aim of this study was to evaluate the effect of two CMF programs (STRESS, ANTIBACTERIAL) against clinical antifungal resistant C. albicans also evaluating their uneffectiveness on gingival fibroblasts (hGFs). The STRESS program was more efficacious on C. albicans biofilm with up to 64.37% ± 10.80 of biomass and up to 99.19% ± 0.06 CFU/ml reductions in respect to the control also inducing an alteration of lipidic structure of the membrane. The MTT assay showed no CMFs negative effects on the viability of hGFs with a major ROS production with the ANTIBACTERIAL program at 3 and 24 h. For the wound healing assay, STRESS program showed the best effect in terms of the rate migration at 24 h, showing statistical significance of p < 0.0001. The toluidine-blue staining observations showed the typical morphology of cells and the presence of elongated and spindle-shaped with cytoplasmic extensions and lamellipodia was observed by SEM. The ANTIBACTERIAL program statistically increased the production of collagen with respect to control and STRESS program (p < 0.0001). CMFs showed a relevant anti-virulence action against C. albicans, no cytotoxicity effects and a high hGFs migration rate. The results of this study suggest that CMFs could represent a novel eco-sustainable strategy to counteract the resistant yeast biofilm infections.

Semi-occlusive CAD/CAM titanium mesh for guided bone regeneration: Preliminary clinical and histological results.

PURPOSE: Guided bone regeneration is a widely used technique for the treatment of atrophic arches. A broad range of devices have been employed to achieve bone regeneration. The present study aimed to investigate the clinical and histological findings for a new titanium CAD/CAM device for guided bone regeneration, namely semi-occlusive titanium mesh. MATERIALS AND METHODS: Nine partially edentulous patients with vertical and/or horizontal bone defects underwent a guided bone regeneration procedure to enable implant placement. The device used as a barrier was a semi-occlusive CAD/CAM titanium mesh with a laser sintered microperforated scaffold with a pore size of 0.3 mm, grafted with autogenous and xenogeneic bone in a ratio of 80:20. Eight months after guided bone regeneration, surgical and healing complications were evaluated and histological analyses of the regenerated bone were performed. RESULTS: A total of 9 patients with 11 treated sites were enrolled. Two healing complications were recorded: one late exposure of the device and one early infection (18.18%). At 8 months, well-structured new regenerated trabecular bone with marrow spaces was mostly present. The percentage of newly formed bone was 30.37% ± 4.64%, that of marrow spaces was 56.43% ± 4.62%, that of residual xenogeneic material was 12.16% ± 0.49% and that of residual autogenous bone chips was 1.02% ± 0.14%. CONCLUSION: Within the limitations of the present study, the results show that semi-occlusive titanium mesh could be used for vertical and horizontal ridge augmentation. Nevertheless, further follow-ups and clinical and histological studies are required.

Mineralization and morphology of peri-implant bone around loaded and unloaded dental implants retrieved from the human mandible.

PURPOSE: Limited data is reported regarding the bone mineralization around dental implants in the first months from insertion. The study analyzed the peri-implant bone around loaded and unloaded implants retrieved from human mandible after 4 months from placement. METHOD: The composition and mineralization of human bone were analyzed through an innovative protocol technique using Environmental-Scanning-Electron-Microscopy connected with Energy-Dispersive-X-Ray-Spectroscopy (ESEM/EDX). Two regions of interest (ROIs, approximately 750×500 µm) for each bone implant sample were analyzed at the cortical (Cortical ROI) and apical (Apical ROI) implant threads. Calcium, phosphorus, and nitrogen (atomic%) were determined using EDX, and the specific ratios (Ca/N, P/N, and Ca/P) were calculated as mineralization indices. RESULTS: Eighteen implant biopsies from ten patients were analyzed (unloaded implants, n=10; loaded implants, n=8). For each ROI, four bone areas (defined bones 1-4) were detected. These areas were characterized by different mineralization degree, varied Ca, P and N content, and different ratios, and by specific grayscale intensity detectable by ESEM images. Bony tissue in contact with loaded implants at the cortical ROI showed a higher percentage of low mineralized bone (bone 1) and a lower percentage of remodeling bone (bone 2) when compared to unloaded implants. The percentage of highly mineralized bone (bone 3) was similar in all groups. CONCLUSION: Cortical and apical ROIs resulted in a puzzle of different bone "islands" characterized by various rates of mineralization. Only the loaded implants showed a high rate of mineralization in the cortical ROI.

Electron Microscopy (EM) Analysis of Collagen Fibers in the Peri-Implant Soft Tissues around Two Different Abutments.

The design of the implant prosthesis-abutment complex appears crucial for shaping healthy and stable peri-implant soft tissues. The aim of the present animal study was to compare two implants with different healing abutment geometries: a concave design (TEST) and a straight one (CTRL). Transmission electron microscopy (TEM) was used to quantify the three-dimensional topography and morphological properties of collagen at nanoscale resolution. 2 swine were included in the experiment and 6 implants per animal were randomly placed in the left or right hemimandible in either the physiologically mature bone present between the lower canine and first premolar or in the mandibular premolar area, within tooth extraction sites. Each CTRL implant was positioned across from its respective TEST implant on the other side of the jaw. After 12 weeks of healing, 8 specimens (4 CTRL and 4 TEST) were retrieved and prepared for histological and TEM analysis. The results showed a significantly higher percentage of area covered by collagen bundles and average bundle size in TEST implants, as well as a significant decrease in the number of longitudinally oriented bundles with respect to CTRL implants, which is potentially due to the larger size of TEST bundles. These data suggest that a concave transmucosal abutment design serves as a scaffold, favoring the deposition and growth of a well-organized peri-implant collagen structure over the implant platform in the early healing phase, also promoting the convergence of collagen fibers toward the abutment collar.

Red Light and 5% Aminolaevulinic Acid (5%) Inhibit Proliferation and Migration of Dysplastic Oral Keratinocytes via ROS Production: An In Vitro Study.

Undiagnosed and untreated oral precancerous lesions often progress into malignancies. Photodynamic therapy (PDT) might be a minimally invasive alternative to conventional treatments. 5-aminolevulinic acid (5-ALA) is one of the most commonly used photosensitizers in PDT, and it is effective on many cancer types. However, its hydrophilic characteristic limits cell membrane crossing. In the present study, the effect of a newly formulated gel containing 5% 5-ALA in combination with red light (ALAD-PDT) on a premalignant oral mucosa cell line was investigated. The dysplastic oral keratinocyte (DOK) cells were incubated with ALAD at different concentrations (0.1, 0.5, 1, and 2 mM) at two different times, 45 min or 4 h, and then irradiated for 7 min with a 630 nm LED (25 J/cm2). MTT assay, flow cytometry, wound healing assay, and quantitative PCR (qPCR) were performed. ALAD-PDT exerted inhibitory effects on the proliferation and migration of DOK cells by inducing ROS and necrosis. mRNA analysis showed modulation of apoptosis-related genes' expression (TP53, Bcl-2, survivin, caspase-3, and caspase-9). Furthermore, there was no difference between the shorter and longer incubation times. In conclusion, the inhibitory effect of the ALAD-PDT protocol observed in this study suggests that ALAD-PDT could be a promising novel treatment for oral precancerous lesions.

Photodynamic Therapy with Aminolevulinic Acid Enhances the Cellular Activity of Cells Cultured on Porcine Acellular Dermal Matrix Membranes Used in Periodontology.

This study aims to test a photodynamic protocol based on a gel containing aminolevulinic acid followed by red-LED (ALAD-PDT) irradiation on human gingival fibroblasts (hGFs) and osteoblasts (hOBs) cultured on a porcine acellular dermal matrix membrane (PADMM). In the previous literature, ALAD-PDT showed solid antibacterial activity and proliferative induction on HGFs cultured on plates and HOBs cultured on a cortical lamina. PADMMs are used in dentistry and periodontology to treat gingival recessions and to increase the tissue thickness in the case of a thin biotype without the risks or postoperative discomfort associated with connective tissue grafts. However, one of the possible complications in this type of surgery is represented by bacterial invasion and membrane exposition during the healing period. We hypothesized that the addition of ALAD-PDT to PADMMs could enhance more rapid healing and decrease the risks connected with bacterial invasion. In periodontal surgery, PADMMs are inserted after a full-thickness flap elevation between the bone and the flap. Consequently, all procedures were performed in parallel on hOBs and hGFs obtained by dental patients. The group control (CTRL) was represented by the unexposed cells cultured on the membranes, group LED (PDT) were the cells subjected to 7 min of red LED irradiation, and ALAD-PDT were the cells subjected to 45 min of ALAD incubation and then to 7 min of red LED irradiation. After treatments, all groups were analyzed for MTT assay and subjected to histological examination at 3 and 7 days and to the SEM observations at 3, 7, and 14 days. Different bone mineralization assays were performed to quantify the effects of ALAD-PDT on hOBs: ALP activity, ALP gene expression, osteocalcin, and alizarin red. The effects of ALAD-PDT on hGFs were evaluated by quantifying collagen 1, fibronectin, and MMP-8. Results showed that ALAD-PDT promoted cellular induction, forming a dense cellular network on hOBs and hGFs, and the assays performed showed statistically significantly higher values for ALAD-PDT with respect to LED alone and CTRLs. In conclusion, ALAD-PDT could represent a promising aid for enhancing the healing of gingival tissues after PADMM applications.

ESEM-EDX Mineralization and Morphological Analysis of Human Retrieved Maxillary Sinus Bone Graft Biopsies before Loading.

This study aimed to analyze the morphology of bone graft granules, the presence of granule demineralization, and bone morphology in retrieved human maxillary sinus bone graft biopsies. Healthy patients underwent sinus bone augmentation using lateral access. Two different dimensions of the antrostomy were performed, a 4 mm or 8 mm height. After 6 months, all sites received one implant using a flap technique, crestal positioning, and submerged healing. Implant biopsies were retrieved after 3 months and were histologically processed. The ESEM analysis was performed on the entire portion of the peri-implant bone (up to 750 µm from the implant thread). Three different regions of interest (ROIs) were selected: the coronal, middle, and apical portions of the implant. In these areas, EDX was performed, and calcium (Ca), phosphate (P), nitrogen (N), and their atomic ratios (Ca/P, Ca/N, and P/N) were calculated. Different bone tissue electron-dense areas were detected through grayscale intensity quantification of ESEM images with different organic (N) or inorganic (Ca,P) compositions. A total of 16 biopsies from 16 healthy patients were analyzed. Bone graft granules were mostly detected in the apical ROI. New bone tissue bridges were detected in the apical and middle ROI. These structures, with lower Ca/N and P/N ratios, were connected and enveloped the bone graft granules. Cortical ROI revealed the most mineralized bone tissue. Conclusions: After 9 months, bone graft resorption was only partially completed and new bone tissue appeared less mineralized in the middle and apical ROI than in the coronal ROI.

Influence of abutment macro- and micro-geometry on morphologic and morphometric features of peri-implant connective tissue.

OBJECTIVES: The aim of the present human observational study is to provide morphologic and morphometric analysis of peri-implant connective tissue next to abutments with divergent or convergent macro-geometry and different surface micro-characteristics. MATERIALS AND METHODS: Thirty patients were rehabilitated with single implants in the posterior area and one out of three different healing abutments with a one-stage technique: machined divergent abutment (DIV-MAC), machined convergent abutment (CONV-MAC) or convergent abutment with ultrathin threaded surface (CONV-UTM). At 3 months postimplant insertion, peri-implant soft tissue was harvested; the following outcomes were investigated: histomorphometry (vertical width of connective and epithelial components) as detected by histology and polarized light; and connective tissue vertical width and 3D organization as detected by synchrotron-based high-resolution phase-contrast-based tomography (PhC-µCT). RESULTS: Significant differences in connective tissue vertical dimension (aJE-AM) were found between DIV-MAC and both CONV-MAC and CONV-UTM, both by histology and PhC-µCT, with significantly higher values for the last two groups. Moreover, 2D histological analysis did not find significant differences in the junctional epithelium vertical dimension (PM-aJE). Importantly, PhC-µCT analysis revealed, at 3D level, significant greater amount and density of collagen bundles for CONV-UTM compared with the other two groups. CONCLUSIONS: Convergent abutment profiles, regardless of their surface micro-geometry, seem to favor axial development of peri-implant connective tissue. Moreover, ultrathin threaded surfaces seem associated with denser and greater connective tissue organization, which might improve peri-implant soft tissue seal.

Alveolar Ridge Preservation Procedures Performed with a Freeze-Dried Bone Allograft: Histologic Outcomes in a Cohort Study.

The primary aim of this study was to assess the histomorphometric outcomes of extraction sockets grafted with freeze-dried bone allograft (FDBA) and sealed with a collagen membrane after 3 months of healing in specific region of interest (ROI) areas. The secondary aims were to analyze the biomaterial resorption rate, the bone-to-biomaterial contact (BBC), and the area and perimeter of grafted particles compared with commercially available FDBA particles. Fifteen patients underwent tooth extractions and ridge preservation procedures performed with FDBA and a collagen membrane. Bone biopsy samples were harvested after 3 months at the time of implant placement for histologic and histomorphometric analysis. Two areas of concern (ROI1 and ROI2) with different histologic features were identified within the biopsy samples; ROI1, ROI2, and commercially available particles were analyzed and compared. The following parameters were analyzed: newly formed bone, marrow space, residual graft particles, perimeter and area of FDBA particles, and BBC. The histomorphometric analysis showed 35.22% ± 10.79% newly formed bone, 52.55% ± 16.06% marrow spaces, and 12.41% ± 7.87% residual graft particles. Moreover, the histologic data from ROI1 and ROI2 showed that (1) the mean percentage of BBC was 64.61% ± 27.14%; (2) the newly formed bone was significantly higher in ROI1 than in ROI2; (3) the marrow space was significantly lower in ROI1 than in ROI2; and (4) the FDBA particles in ROI1 sites showed significantly lower area and perimeter when compared to commercially available FDBA particles. This latter data led to the hypothesis that FDBA particles embedded in newly formed bone undergo a resorption/remodeling process.

Effect of alveolar ridge preservation on peri-implant mucositis and peri-implantitis prevalence: A multicenter, cross-sectional study.

OBJECTIVES: Alveolar ridge preservation (ARP) is a procedure with the aim to reduce bone resorption that occurs after tooth extraction, facilitating the following implant placement. The aim of this cross-sectional study was to evaluate the prevalence of mucositis and peri-implantitis around implants inserted in sites treated with ARP and to investigate possible risk factors. MATERIALS AND METHODS: Patients who received at least one dental implant inserted in a grafted socket were considered eligible for this study. Patients were recalled for a follow-up visit; medical history, clinical and demographic data were collected. Univariate logistic regression analyses have been performed for both implant-level and patient-level variables. Indeed, moderation analysis was used to investigate the indirect relationship between age and marginal bone level. RESULTS: Fifty-one patients who received 61 implants were enrolled in this cross-sectional study. Thirty-three implants were classified as "healthy" (54.1%), 23 implants showed signs of peri-implant mucositis (37.7%), and 5 implants were diagnosed with peri-implantitis (8.2%). Data analyzed at the patient level showed that 49% of the patients were healthy, 45.1% of the patients had mucositis and 5.9% of the patients were affected by peri-implantitis. Mandibular sites and type III grafted sockets showed a significant association with peri-implantitis; in addition, a history of periodontitis and an increase in age showed higher risks of developing mucositis or peri-implantitis. CONCLUSIONS: Implants inserted in grafted sockets showed favorable rates of healthy implants in the long term. CLINICAL RELEVANCE: The ridge preservation procedures do not seem to increase the risk of developing mucositis or peri-implantitis.

Hemostatic Collagen Sponge with High Porosity Promotes the Proliferation and Adhesion of Fibroblasts and Osteoblasts.

The use of biomaterial for tissue repair involves the interaction between materials and cells, and the coagulum formation represents the first step of tissue healing. This process is particularly critical in the oral cavity, where the wounds are immediately subjected to the masticatory mechanical stress, saliva invasion, and bacterial attack. Therefore, the present study aimed to explore the structural features and the biological activities of a hemostatic collagen sponge on human gingival fibroblasts (HGFs) and human oral osteoblasts (HOBs). The microstructure of the collagen sponge was characterized by a scanning electron microscope (SEM) and histological analysis. The porosity was also calculated. To investigate biological activities, HGFs and HOBs were cultured on the collagen sponges, and their adhesion was observed at SEM on the third day, while cell viability was investigated at the third and seventh days by Tetrazolium (MTT) assay. For osteoblasts seeded on collagen sponge the mineralization ability was also evaluated by alkaline phosphatase (ALP) assay at the seventh day, and by Alizarin red staining on the 14th. Furthermore, the gene expression of ALP and osteocalcin (OCN) was investigated after 3, 7 and 14 days. SEM images of the sponge without cells showed a highly porous 3D structure, confirmed by the measurement of porosity that was more than 90%. The samples cultured were characterized by cells uniformly distributed and adhered to the sponge surface. Proliferation ended up being promoted, as well as the mineralization ability of the osteoblasts, mainly at the mature stage. In conclusion, this collagen sponge could have a potential use for tissue healing.

The Antibacterial and Antifungal Capacity of Eight Commercially Available Types of Mouthwash against Oral Microorganisms: An In Vitro Study.

This work aimed to evaluate and compare the antimicrobial actions and effects over time of eight types of mouthwash, based on the impact of chlorhexidine on the main microorganisms that are responsible for oral diseases: Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans. The mouthwashes' antimicrobial action was determined in terms of their minimum inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration (MBC/MFC), and time-kill curves at different contact times (10 s, 30 s, 60 s, 5 min, 15 min, 30 min, and 60 min), against selected oral microorganisms. All the mouthwashes showed a notable effect against C. albicans (MICs ranging from 0.02% to 0.09%), and higher MIC values were recorded with P. aeruginosa (1.56% to >50%). In general, the mouthwashes showed similar antimicrobial effects at reduced contact times (10, 30, and 60 s) against all the tested microorganisms, except with P. aeruginosa, for which the most significant effect was observed with a long time (15, 30, and 60 min). The results demonstrate significant differences in the antimicrobial actions of the tested mouthwashes, although all contained chlorhexidine and most of them also contained cetylpyridinium chloride. The relevant antimicrobial effects of all the tested mouthwashes, and those with the best higher antimicrobial action, were recorded by A-GUM® PAROEX®A and B-GUM® PAROEX®, considering their effects against the resistant microorganisms and their MIC values.

Functionalization of a Cortical Membrane with a Photodynamic Protocol.

Guided bone regeneration (GBR) comprehends the application of membranes to drive bone healing and to exclude non-osteogenic tissues from interfering with bone regeneration. However, the membranes may be exposed to bacterial attack, with the risk of failure of the GBR. Recently, an antibacterial photodynamic protocol (ALAD-PDT) based on a gel with 5% 5-aminolevulinic acid incubated for 45 min and irradiated for 7 min by a LED light at 630 nm, also showed a pro-proliferative effect on human fibroblasts and osteoblasts. The present study hypothesized that the functionalization of a porcine cortical membrane (soft-curved lamina, OsteoBiol) with ALAD-PDT might promote its osteoconductive properties. TEST 1 aimed to verify the response of osteoblasts seeded on lamina with respect to the plate surface (CTRL). TEST 2 aimed to investigate the effects of ALAD-PDT on the osteoblasts cultured on the lamina. SEM analyses were performed to study the topographical characteristics of the membrane surface, the adhesion, and the morphology of cells at 3 days. The viability was assessed at 3 days, the ALP activity at 7 days, and calcium deposition at 14 days. Results showed the porous surface of the lamina and the increase in cell attachment of osteoblasts with respect to controls. The proliferation, the ALP, and bone mineralization activity of osteoblasts seeded on lamina resulted in being significantly higher (p < 0.0001) than controls. Results also showed an additional significative enhancement (p < 0.0001) in the proliferative rate in ALP and calcium deposition after applying ALAD-PDT. In conclusion, the functionalization of the cortical membranes cultured with osteoblasts with the ALAD-PDT improved their osteoconductive properties.

Emerging Effects of Resveratrol Derivatives in Cells Involved in Oral Wound Healing: A Preliminary Study.

Recently, there has been an increasing interest in finding new approaches to manage oral wound healing. Although resveratrol (RSV) exhibited many biological properties, such as antioxidant and anti-inflammatory activities, its use as a drug is limited by unfavorable bioavailability. This study aimed to investigate a series of RSV derivatives (1a-j) with better pharmacokinetic profiles. At first, their cytocompatibility at different concentrations was tested on gingival fibroblasts (HGFs). Among them, derivatives 1d and 1h significantly increased cell viability compared to the reference compound RSV. Thus, 1d and 1h were investigated for cytotoxicity, proliferation, and gene expression in HGFs, endothelial cells (HUVECs), and oral osteoblasts (HOBs), which are the main cells involved in oral wound healing. For HUVECs and HGFs, the morphology was also evaluated, while for HOBs ALP and mineralization were observed. The results showed that both 1d and 1h did not exert negative effects on cell viability, and at a lower concentration (5 µM) both even significantly enhanced the proliferative rate, compared to RSV. The morphology observations pointed out that the density of HUVECs and HGFs was promoted by 1d and 1h (5 µM) and mineralization was promoted in HOBs. Moreover, 1d and 1h (5 µM) induced a higher eNOS mRNA level in HUVECs, higher COL1 mRNA in HGFs, and higher OCN in HOBs, compared to RSV. The appreciable physicochemical properties and good enzymatic and chemical stability of 1d and 1h, along with their promising biological properties, provide the scientific basis for further studies leading to the development of RSV-based agents useful in oral tissue repair.

Osteoblasts and Fibroblasts Interaction with a Porcine Acellular Dermal Matrix Membrane.

The use of collagen membranes has remained the gold standard in GTR/GBR. In this study, the features and the biological activities of an acellular porcine dermis collagen matrix membrane applicable during dental surgery were investigated, and also by applying hydration with NaCl. Thus, two tested membranes were distinguished, the H-Membrane and Membrane, compared to the control cell culture plastic. The characterization was performed by SEM and histological analyses. In contrast, the biocompatibility was investigated on HGF and HOB cells at 3, 7, and 14 days by MTT for proliferation study; by SEM and histology for cell interaction study; and by RT-PCR for function-related genes study. In HOBs seeded on membranes, mineralization functions by ALP assay and Alizarin Red staining were also investigated. Results indicated that the tested membranes, especially when hydrated, can promote the proliferation and attachment of cells at each time. Furthermore, membranes significantly increased ALP and mineralization activities in HOBs as well as the osteoblastic-related genes ALP and OCN. Similarly, membranes significantly increased ECM-related and MMP8 gene expression in HGFs. In conclusion, the tested acellular porcine dermis collagen matrix membrane, mainly when it is hydrated, behaved as a suitable microenvironment for oral cells.