Platelet rich growth factor in the treatment of complex corneal disorders

Background. Platelet rich growth factor (PRGF) is an autologous blood product rich in proteins and growth factors which can be rapidly obtained from patient blood. Clinically, it is an affordable treatment with potentially broad spectrum of applications in ophthalmology especially in the treatment of complex or refractory corneal wounds. The aim of this study was to evaluate the efficiency of autologous platelet-rich factor in the treatment of complex corneal disorders. The study was performed at the Ophthalmology Department of International Clinic, Orhei, Moldova in January - December 2022. Materials and Methods. There were 28 patients with corneal surface disorders, among which 7 patients with chemical burns, 4 patients with corneal ulcers, 5 patients with corneal dystrophies, 8 with advanced pterygium and 4 with neurotrophic keratopathy. Visual acuity varied from hand motion to 0.7. Solid PRGF was either just placed on the corneal surface or sutured with 2 nodes of 10-00 nylon suture at conjunctiva. If necessary, the procedure was repeated. All patients had corneal OCT scan before and after the treatment. Results. Improved visual acuity and less subjective symptoms were observed in all patients. Complete healing of cornea was observed in all patients with chemical burns and corneal dystrophies. As well considerable improvement experienced 3 of 4 patients with corneal ulcers (reduced size and depth of the ulceration, improved visual acuity, smaller conjunctival injection). Also an improvement was seen in 2 of 4 patients with neurotrophic keratopathy. All patients after pterygium surgery had clear cornea and no recurrences over 6-month period after treatment None of the patients reported general or local side effects of the treatment. Conclusions: PRGF is a reliable and effective therapeutic tool to promote wound healing in complex corneal disorders

Does intraoperative bone density testing correlate with parameters of primary implant stability? A pilot study in minipigs

Objectives: Bone density, surgical protocol, and implant design are the major deter-minants of primary stability. The goal of this animal trial was to investigate potentialcorrelations of intraoperative bone density testing with clinical and histologic param-eters of primary implant stability.Material and methods: Following extractions of all mandibular premolars and subse-quent healing, four implants each were placed in a total of four minipigs. Bone den-sity was determined by applying intraoperative compressive tests using a devicenamed BoneProbe whereas measurements of implant insertion torque and resonancefrequency analysis were used for evaluating implant stability. Bone mineral density(BMD) and bone to implant contact were quantified after harvesting mandibularblock sections. Spearman rank correlation tests were performed for evaluating corre-lations (α = .05).Results: Due to variation in clinical measurements, only weak correlations could beidentified. A positive correlation was found between the parameters bone to implantcontact and BMD (Spearman's rho .53; p=.05) whereas an inverse correlation wasobserved between BMD and implant stability (Spearman's rho −.61; p=.03). BothBoneProbe measurements in the cortical and trabecular area positively correlatedwith implant insertion torque (Spearman's rho 0.60; p=.02). A slightly stronger corre-lation was observed between the average of both BoneProbe measurements andimplant insertion torque (Spearman's rho.66; p=.01).Conclusions: While establishing exact relationships among parameters of implant sta-bility and the measurement techniques applied would require greater sample size,intraoperative compressive testing of bone might, despite the weak correlations seenhere, be a useful tool for predicting primary implant stability

Electrochemical Disinfection of Root Canals Bears No Risk of Damaging Periapical Tissues in a Dog Model

Boron-doped diamond (BDD) electrodes have been advocated as a potential treatment alternative to the established methods for root canal disinfection. As healing of periapical tissue is important in this context, the associated risk of host tissue damage was to be evaluated. Following in vitro cell culture experiments (HeLa cells), root canal treatment was performed in an animal trial comparing BDD electrode application and the currently used rinsing media with respect to cell viability and host tissue damage. Statistical analyses comparing the size of radiolucency were based on Kruskal-Wallis and Nemenyi’s All Pairs tests (α = 0.05). The direct application of BDD electrodes had a time-dependent effect on cell viability comparable to H2O2 , NaOCl, and CHX application. In contrast to the chemical treatment, the effect of BDD electrodes was transient. Conventionally treated teeth and teeth additionally treated with BDD electrodes did not significantly differ from each other with respect to the size of the periapical radiolucency as observed radiographically (vertical p = 0.998 and horizontal p = 0.878) and histologically (vertical p = 0.940 and horizontal p = 0.862). While showing greater disinfection efficiency, the application of BDD electrodes for the electrochemical disinfection of root canals does not have a greater risk of host tissue damage compared to the conventional treatment

Pilot study on the applicability of boron-doped diamond electrodes for tooth whitening

Objectives While various approaches are available for tooth whitening, the basic concept employs the use of peroxides in the form of gels, which are applied to tooth surfaces. Previous studies have shown that reactive oxygen species acting as potent disinfectants can be produced using boron-doped diamond (BDD) electrodes for the electrolysis of water. With these electrodes being applicable, for example, for endodontic treatment, it was the goal of this pilot study to use such electrodes for tooth whitening. Material and Methods Two groups (n = 10) of intact clinical crowns were obtained by horizontally cutting off roots of extracted human teeth. The crowns were either bleached by applying a commercially available agent based on 40% hydrogen peroxide or were immersed in saline undergoing electrolysis with BDD electrodes. Whitening of specimens was judged on standardized photographs by examiners with three different levels of experience. Statistical analysis was based on Gwet's AC2 coefficient with quadratic weights, Shapiro–Wilk tests, and two-way analysis of variance of aligned rank transformed data (level of significance set at α = .05). Results Levels of reliability ranging from fair to substantial were recorded for single persons while the level of reliability ranged between fair and moderate for groups of raters. The level of experience had no significant effect on the ratings (p = .2500). The bleaching method had a significant effect on ratings (p = .0005) with BDD electrodes showing less effect. Conclusions Bleaching by applying BDD electrodes was possible, but was not as effective as the use of commercially available in-office whitening gel. A potential explanation may be seen in different concentrations of reactive oxygen species

Preclinical Testing of Boron-Doped Diamond Electrodes for Root Canal Disinfection—A Series of Preliminary Studies

While numerous approaches have meanwhile been described, sufficient disinfection of root canals is still challenging, mostly due to limited access and the porous structure of dentin. Instead of using different rinsing solutions and activated irrigation, the electrolysis of saline using boron-doped diamond (BDD) electrodes thereby producing reactive oxygen species may be an alternative approach. In a first step, experiments using extracted human teeth incubated with multispecies bacterial biofilm were conducted. The charge quantities required for electrochemical disinfection of root canals were determined, which were subsequently applied in an animal trial using an intraoral canine model. It could be shown that also under realistic clinical conditions, predictable disinfection of root canals could be achieved using BDD electrodes. The parameters required are in the range of 5.5 to 7.0 V and 9 to 38 mA, applied for 2.5 to 6.0 min with approximately 5 to 8 mL of saline. The direct generation of disinfective agents inside the root canal seems to be advantageous especially in situations with compromised access and limited canal sizes. The biologic effect with respect to the host reaction on BDD-mediated disinfection is yet to be examined

Root Canal Obturation by Electrochemical Precipitation of Calcium Phosphates

Achieving adequate disinfection and preventing reinfection is the major goal in endodontic treatment. Variation in canal morphology and open porosity of dentine prevents achieving complete disinfection. Questionable biocompatibility of materials as well as a lack of sealing ability questions the usefulness of current obturation methods. With a novel disinfection approach based on the use of boron-doped diamond (BDD) electrodes having shown promising results it was the goal of this series of experiments to investigate the possibility of BDD-mediated in situ forming of a biocompatible obturation material. A combination of calcium phosphate and maleic acid was used as precursor solution while Ion Chromatography Mass Spectrometry (IC-MS), Raman spectroscopy (RAMAN), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), dye penetration and micro-computed tomography (µCT) were applied for characterizing the precipitate. It was possible to achieve a BDD-mediated precipitation of brushite in a clinically applicable timeframe. However, tight sealing of the canal system based on brushite could not be achieved

Bone tissue regeneration using different 3D matrices

Introduction. There are several types of grafts used in the treatment of bone defects [1]. During the research, was tested the regeneration capacity of critical bone defects with several types of materials. Materials and methods. To 18 New Zealand rabbits, under general anesthesia in both parietal bones, 8 mm in diameter critical defects were made. In the defects made in the right parietal bones were transplanted (n=3): collagen sponges cross-linked with 25% glutaraldehyde (GA) vapours, collagen sponges cross-linked with 25 mM riboflavin under UV-A [3], lamellas of demineralised bone matrix (DBM), shredded DBM [2], and 3D printed PLA discs; the control materials were transplanted in defects made in the left parietal bones: minced autologous iliac bone and Colapan. The rabbits were removed from the experiment at 12 weeks, the calvarias were fixed in 10% buffered formaldehyde. The regenerated defects were examined histologically by Hematoxylin-Eosin staining, and scanning electron microscopy (SEM) [4]. Results. The histological examination of defects treated with minced autologous bone showed an inflammatory process with necrosis and resorption of transplanted bone trabeculae. In defects treated with Colapan formation of bone trabeculae in the areas of contact with the native bone was determined. The defects treated with cross-linked collagen sponges showed a dense and regularly distributed collagen fibers when using GA and degenerated, loose with thin fibrillar structure for riboflavin. When DBM lamellas were used, debris of DBM matrix and disorganized fibrous connective tissue with an infiltrative character were found. The shredded DBM fragments were consolidated with fibrous tissue and at the periphery of the fragments, trabecular extensions of newly formed bone were determined. In spaces between filaments of PLA discs were found thick collagen fibers forming bundles and newly formed trabeculae of reticular fibrous bone. SEM showed that transplanted materials changed significant their structure except the PLA discs. Conclusions. The difference between the obtained results showed that not all materials can be used for an efficient regeneration of critical bone tissue defects. Compared to the control and the other experimental groups, shredded DBM at 12 weeks filled the defect with bone-like tissue

In Vitro Evaluation of the Cytotoxic Potential of Thiosemicarbazide Coordinating Compounds in Hepatocyte Cell Culture

Cancer is a global medical problem and, despite research efforts in the field of tumor treatment, there is currently a shortage of specific anticancer drugs. Most anticancer drugs show significant side effects. The liver is the organ that has central functions in drug metabolism, being a major target of the harmful action of anticancer compounds. In this context, it is essential to evaluate the cytotoxic effects of potential anticancer substances. Therefore, hepatotoxicity and hepatocyte viability were determined in vitro to evaluate the action of seven new local thiosemicarbazide coordination compounds (CCT) on normal liver cells. Doxorubicin was used as a reference substance. The control group consisted of hepatocytes not exposed to CCT action. The cell viability of hepatocytes treated with CCT decreased significantly by 5–12% compared to the control, but was statistically significantly higher by 5–14% compared to doxorubicin, except after CMD-8 and CMT-67 influence, when it does not change. Thus, new local CCT had a selective effect on hepatocytes in vitro and were less hepatotoxic compared to doxorubicin, which may be the basis for further study of its potential in anticancer drugs

In Vitro Evaluation of the Cytotoxic Potential of Thiosemicarbazide Coordinating Compounds in Hepatocyte Cell Culture

Cancer is a global medical problem and, despite research efforts in the field of tumor treatment, there is currently a shortage of specific anticancer drugs. Most anticancer drugs show significant side effects. The liver is the organ that has central functions in drug metabolism, being a major target of the harmful action of anticancer compounds. In this context, it is essential to evaluate the cytotoxic effects of potential anticancer substances. Therefore, hepatotoxicity and hepatocyte viability were determined in vitro to evaluate the action of seven new local thiosemicarbazide coordination compounds (CCT) on normal liver cells. Doxorubicin was used as a reference substance. The control group consisted of hepatocytes not exposed to CCT action. The cell viability of hepatocytes treated with CCT decreased significantly by 5%-12% compared to the control, but was statistically significantly higher by 5%-14% compared to doxorubicin, except after CMD-8 and CMT-67 influence, when it does not change. Thus, new local CCT had a selective effect on hepatocytes in vitro and were less hepatotoxic compared to doxorubicin, which may be the basis for further study of its potential in anticancer drugs