Psychoactive substance use in patients diagnosed with attention-deficit/hyperactivity disorder: an exploratory study.

Introduction: Attention-deficit/hyperactivity disorder (ADHD) was originally treated as a neurodevelopmental disorder that occurs mainly in children and tends to diminish or disappear with age, but we now know that symptoms persist into adulthood in over 50% of ADHD patients. Undiagnosed individuals often turn to psychoactive substance to minimize the negative aspects of functioning and improve quality of life. Methods: The study was conducted online using random sampling through a Facebook group administered by physicians and targeted to patients diagnosed with ADHD. The study was naturalistic and exploratory, therefore no hypothesis was made. 438 correctly completed questionnaires were received. Analysis of the results showed that people with ADHD turn to psychoactive substances relatively frequently. Results: The most commonly used stimulants include alcohol, marijuana, 3,4-methylenedioxymethamphetamine (MDMA), amphetamine/methamphetamine, and psilocybin. In the study population, methylphenidate is the most commonly used drug among patients. After treatment with psychostimulants, the majority of respondents note a decrease in symptoms of hyperactivity disorder, especially in male patients. Conclusion: It is necessary to perform proper diagnostics and actively look for ADHD symptoms in patients who tend to use psychoactive substances.

Telemetric Assessment of Continuous Positive Airways Pressure (CPAP) Effectiveness and Adherence in Obstructive Sleep Apnea during COVID-19 Pandemic.

Obstructive sleep apnea is the most common sleep-related breathing disorder. In the pandemic times of the new coronavirus SARS-CoV-2, CPAP (Continuous Positive Airway Pressure) therapy of obstructive sleep apnea became even more challenging. After the pandemic outbreak in March 2020, most CPAP treatment recommendations changed because of rising concerns about CPAP usage safety for patients and their families. Therefore, we examined the effectiveness of CPAP and adherence to the therapy of 149 adults with obstructive sleep apnea in the period of two years from 4 March 2019 to 3 March 2021 (before pandemic breakout and during the first year of pandemic). Data on CPAP parameters and adherence to therapy were obtained via a telemetric system. Together, our results demonstrated that the COVID-19 pandemic had no significant impact on CPAP therapy parameters and adherence in whole study group. However, detailed analysis acknowledged that some demographic and clinical features influenced CPAP therapy. The results showed that across subgroups of patients differentiated on the basis of age, gender, co-existing diabetes mellitus, or hypertension, the COVID-19 pandemic seemed to affect CPAP effectiveness. Our results provide a good starting point for discussion on CPAP therapy recommendations during pandemic times.

The Effect of Chlorhexidine Disinfectant Gels with Anti-Discoloration Systems on Color and Mechanical Properties of PMMA Resin for Dental Applications.

Chlorhexidine (CHX)-based dental hygiene products are widely used by dental patients. As these products may have long-term contact with denture poly(methyl methacrylate) (PMMA) resin, anti-discoloration systems (ADSs) were included in them to prevent discoloration of the natural teeth and dental materials. Purpose: The aim of this study was to evaluate the effect of two newly designed CHX-containing gels with ADSs and two commercial products with ADSs (Curasept 0.5% and Curasept 1%) in preventing staining and to analyze the mechanical properties of heat-curing PMMA denture base resin. Materials and methods: Twenty-five discs (five for each test group) of PMMA dental resin with a thickness of 1 mm and a diameter of 20 mm were polymerized according to the manufacturer's instructions and stored in distillate water at a temperature of 37 °C. The surface of the specimens was covered with two commercially available gels-Curasept 1% and Curasept 0.5%, or two experimental gel formulations containing 1% CHX. PMMA specimens stored in distilled water were used as control. The initial values of color and Brinell hardness of the specimens were measured immediately after specimen preparation. The changes in color and Brinell hardness, as well as water sorption, and solubility of the specimens were measured after one year of conditioning. Statistical analysis of the obtained data was performed using one-way analysis of variance and Dunn-Bonferroni post hoc tests. Results: In the group of specimens covered with gel 1 with citric acid or Curasept 0.5%, the color change was clinically acceptable (ΔE* < 2.7). In the specimens stored in contact with gel 2 with polyvinylpyrrolidone (PVP) and Curasept 1%, the ΔE* values were 3.6 and 3.67, respectively. In the control group, the level of hardness decreased significantly from 150 to 140 during the experiment. In addition, a statistically significant decrease in hardness was observed in specimens stored with Curasept 1% and gel 2 with PVP. Specimens stored in contact with Curasept 0.5% and gel 1 with citric acid also showed a lower hardness, but the change was not statistically significant. The sorption of all the groups of PMMA specimens ranged from 22.83 to 24.47 µg/mm3, with no significant differences found between them. All the PMMA specimens stored in contact with the tested CHX gels exhibited a significantly higher solubility (6.84 ± 7.91 µg/mm3) compared to the control group (6.74 µg/mm3), with the highest solubility noted for specimens stored with Curasept 1%. Conclusions: The results showed that CHX used in the gel form with ADSs at a concentration of 0.5% and the experimental gel containing 1% CHX with citric acid caused limited changes to the color and mechanical properties of the PMMA denture base resin during the study period. These gels may be safely used by dental patients for oral hygiene regimen even for prolonged periods of time. ADSs contained in these gels seem to be effective in preventing CHX discoloration.

Adhesion as a component of retention force of overdenture prostheses-study on selected Au based dental materials used for telescopic crowns using atomic force microscopy and contact angle techniques.

Contemporary prosthetic materials are characterized by highly specific preparation for a given application. This means that at the stage of their creation, not only their function is taken into account, but also the long-term behavior of this material during use. In the case of telescopic crowns, an important factor not yet appearing in the research is the aspect of adhesion force and its dependence on the type of biomaterial, but also the properties of human saliva. The use of artificial saliva, which creates a lubricating layer, reduces the wear on the surface of the telescopic crowns by reducing friction. The impact of artificial saliva on the formation of chemical bonds between prosthetic elements, thus contributing to the so-called retention force has not yet been studied. In this work, two types of measurements of gold telescopic crown materials in the aspect of the adhesion process are presented. Obtained results allowed to fully characterize this phenomenon. We modeled the load force between the microcircuit and the surface under study to suit the conditions between the primary and secondary crowns in the patient's mouth.

Release and Recharge of Fluoride Ions from Acrylic Resin Modified with Bioactive Glass.

BACKGROUND: Oral hygiene is essential for maintaining residual dentition of partial denture wearers. The dental material should positively affect the oral environment. Fluoride-releasing dental materials help to inhibit microbial colonization and formation of plaque as well as to initiate the remineralization process in the early cavity area. AIM: To evaluate fluoride ion release and recharge capacity, sorption, and solubility of polymethyl methacrylate (PMMA) dental resin modified with bioactive glass addition. MATERIALS AND METHODS: Two bioactive glass materials (5 wt% Kavitan, 10 wt% Kavitan, and 10 wt% Fritex) and pure 10 wt% NaF were added to dental acrylic resin. After polymerization of the modified resins, the release levels of fluoride anions were measured based on color complex formation by using a spectrophotometer after 7, 14, 28, and 35 days of storage in distilled water at 37 °C. Subsequently, specimens were brushed with a fluoride-containing tooth paste on each side for 30 s, and the fluoride recharge and release potential was investigated after 1, 7, and 14 days. Sorption and solubility after 7 days of storage in distilled water was also investigated. RESULTS: The acrylic resins with addition of 10% bioactive glass materials released fluoride ions for over 4 weeks (from 0.14 to 2.27 µg/cm2). The amount of fluoride ions released from the PMMA resin with addition of 10 wt% Fritex glass was higher than that from the resin with addition of 10 wt% Kavitan. The acrylic resin containing 10 wt% NaF released a high amount of ions over a period of 1 week (1.58 µg/cm2), but the amount of released ions decreased rapidly after 14 days of storage. For specimens containing 5 wt% Kavitan glass, the ion-releasing capacity also lasted only for 14 days. Fluoride ion rechargeable properties were observed for the PMMA resin modified with addition of 10 wt% Fritex glass. The ion release levels after recharge ranged from 0.32 to 0.48 µg/cm2. Sorption values ranged from 10.23 µm/mm3 for unmodified PMMA resin to 12.11 µm/mm3 for specimens modified with 10 wt% Kavitan glass. No significant differences were found regarding solubility levels after 7 days. CONCLUSIONS: The addition of 10 wt% Fritex and 10 wt% Kavitan bioactive glass materials to heat-cured acrylic resin may improve its material properties, with bioactive fluoride ion release ability lasting for over 4 weeks. The resin modified with 10 wt% Fritex glass could absorb fluoride ions from the toothpaste solution and then effectively release them. Addition of fluoride releasing fillers have a small effect on sorption and solubility increase of the modified PMMA resin. CLINICAL SIGNIFICANCE: The addition of bioactive glass may be promising in the development of the novel bioactive heat-cured denture base resin.

Biological Response Induced in Primary Human Gingival Fibroblasts upon Exposure to Various Types of Injectable Astringent Retraction Agents.

Traditional chemo-mechanical retraction/displacement materials can impact the gingival margin tissues. This study was undertaken to analyze biological responses induced in human gingival fibroblasts (HGFs) upon application of injectable astringent-based agents used in the cordless retraction technique. HGFs were exposed to hemostatic agents (five gels, three pastes, and one foam) based on aluminium chloride, aluminium sulphate and ferric sulphate. Changes in cell viability and proliferation were evaluated using an MTT assay and a BrdU assay. The cytoskeleton structure organization (zyxin and F-actin) was visualized by confocal laser scanning microscopy. Oxidative stress was determined using the Griess Reagent System. The RNA expression levels of antioxidant enzymes were quantified by real-time RT-PCR. The statistical significance was evaluated using Student's t-test and one-way ANOVA with post-hoc Tukey HSD test. The evaluated agents did not downregulate fibroblast viability or proliferation. No significant cytoskeleton reorganization was observed. Only one agent (Expasyl) induced oxidative stress, demonstrated by the increased level of nitrites. Incubation with the studied agents significantly increased the RNA expression of some antioxidant enzymes (SOD1, SOD3, GPX1). However, no significant influence on the expression of SOD2 and HMOX1 was detected. The injectable forms of chemical retraction agents revealed biocompatibility with HGFs, suggesting their potential clinical usefulness in gingival margin retraction.

Update on Acrylic Resins Used in Dentistry.

Acrylic resins are the most commonly used materials in prosthetics and orthodontics until now. They have a well-documented history of use as biomaterials in the manufacturing of different types of dental appliances. The objective of this study was to describe the properties of acrylic resins and the processing methods used for these materials in dentistry. The review depicts the most important achievements in this area, indicating that the resin technology evolved in different directions. The mechanical and biological properties of acrylic resins were improved by the addition of mineral or natural fibers, and/or fillers, including nanofillers, as well as by poly(methyl methacrylate) surface modification. The presence of residual monomer was reduced as a result of postpolymerization activity. New types of acrylic resins were developed for processing Computer-Aided Design/Computer- Aided Manufacturing systems and three-dimensional printing.

The three-point bending test of fiber-reinforced composite root canal posts.

BACKGROUND: The primary reason for using a post is to retain the core with the objective to restore the missing coronal tooth structure. To achieve optimum results, the materials that are used to restore endodontically treated teeth should have physical and mechanical properties that are similar to that of dentin. OBJECTIVES: To characterize the strength parameters of fiber-reinforced composite (FRC) posts with the application of a three-point test. The mean fracture load, flexural strength and flexural modulus were taken into consideration. MATERIAL AND METHODS: For the three-point strength tests, 5 kinds of fiberglass root-posts were used: GC Fiber Post (GC America, Alsip, USA), Mirafit White (Hager Werken, Duisburg, Germany), Innopost (InnoTech, Verona, Italy), Rebilda Post (Voco, Cuxhaven, Germany), and EverStick Post (GC Europe, Leuven, Belgium). For each system, 15 FRC posts were tested. All posts had the same diameter, length and shape. The three-point test was carried out in accordance with ISO 10477:2004, using the Instron-5944 testing machine (Instron, Norwood, USA). The test was carried out until the sample was broken. RESULTS: The highest force values (67.6 N) were recorded for the GC posts, and the lowest force required to break the sample (29.6 N) was noted for the EverStick Posts. In the case of bending strength, the highest values were also recorded for GC posts (912.4 MPa). Low bending strengths were obtained for the Mirafit White posts (537.2 MPa); however, the EverStick Posts were the weakest (436.2 MPa). Rebilda posts showed the highest modulus of elasticity - 31.1 GPa. The lowest values of the elastic modulus were registered for EverStick Posts - 12.5 GPa. CONCLUSIONS: There were statistically significant differences in fracture loads, flexural strengths and flexural modulus of the FRC-post systems tested. Individually polymerized FRC material showed lower flexural properties than compared prefabricated FRC posts.

Polish Propolis-Chemical Composition and Biological Effects in Tongue Cancer Cells and Macrophages.

The purpose of this study was to compare the chemical composition and biological properties of Polish propolis. Ethanol, ethanol-hexane, hexane and hexane-ethanol extracts of propolis from three different regions of Poland were prepared. On the basis of the evaluation of their chemical composition as well as the extraction yield and free radical scavenging activity, the ethanol and hexane-ethanol extractions were proposed as the most effective methods. Subsequently, the biological properties of the extracts were evaluated to investigate the selectivity of an anticancer effect on tongue cancer cells in comparison to normal gingival fibroblasts. The obtained products demonstrated anticancer activity against tongue cancer cells. Additionally, when the lowest extract concentration (100 µg/mL) was applied, they were not cytotoxic to gingival fibroblasts. Finally, a possible anti-inflammatory potential of the prepared products was revealed, as reduced mitochondrial activity and proliferation of macrophages exposed to the extracts were observed. The results obtained indicate a potential of Polish propolis as a natural product with cancer-selective toxicity and anti-inflammatory effect. However, further studies are still needed to thoroughly explain the molecular mechanisms of its action and to obtain the promising health benefits of this versatile natural product.

Influence of silanized silica and silanized feldspar addition on the mechanical behavior of polymethyl methacrylate resin denture teeth.

STATEMENT OF PROBLEM: Artificial denture teeth made of polymethyl methacrylate (PMMA) resin have good adhesion to the denture base but are relatively soft and have limited wear resistance during function. PURPOSE: The purpose of this in vitro study was to evaluate the influence of the addition of 2 inorganic nanofillers on the flexural strength, maximal displacement, elastic modulus, Isolde impact resistance, and Brinell hardness of acrylic resin denture teeth. MATERIAL AND METHODS: Heat polymerizing polymethyl methacrylate resin was mixed with silanized silica or silanized feldspar in concentrations of 5 wt%, 10 wt%, and 15 wt%. The first test was conducted after 24 hours of storage in laboratory conditions, and the second assessment was conducted after 3 months of storage in distilled water at 37 °C. The Brinell hardness was evaluated, and the elastic modulus and maximal displacement at fracture were calculated. The flexural strength and Isolde impact resistance were measured with a 3-point flexural test. Acrylic resin specimens without filler addition were used as a control group. Statistical analysis included 2-way ANOVA for independent variables (α=.05) and the Student t test for time-dependent changes (α=.05). These were performed with Statistica 12 software. RESULTS: The acrylic resin specimens modified with the addition of silanized feldspar had significantly higher Brinell hardness, elastic modulus, maximal displacement, and flexural strength and also had no adverse effect on Isolde impact resistance compared with the conventional acrylic resin. Silica filler increased the Brinell hardness and elastic modulus of acrylic resins but significantly reduced the flexural strength and Isolde impact resistance.

In vitro effects of vasoconstrictive retraction agents on primary human gingival fibroblasts.

The biological activity of chemical retraction/displacement agents in surrounding periodontal tissues is of unquestionable importance, but the activity of these agents has not been completely elucidated. In the present study, we aimed to evaluate the in vitro effects of vasoconstrictive retraction agents on primary human gingival fibroblasts (HGFs). A total of six commercial adrenergic solutions (0.05 and 0.01% HCl-epinephrine, two based on 0.05% HCl-tetrahydrozoline, 0.05% HCl-oxymetazoline, and 10% HCl-phenylephrine) and three experimental gel formulations (EG-1, EG-2, and EG-3) were used to treat primary HGFs. The biological effect of the retraction treatment on the expression of collagen types I and III was detected by performing immunocytochemical analysis. The generation of reactive oxygen species triggered by the retraction agents were evaluated by using the dichlorofluorescein (DCF) fluorescent probe. The effect of retraction agents on the expression of fibronectin was visualized by confocal laser scanning microscopy. According to the results, experimental retraction gels did not limit the expression of collagen types I and III. EG-3 even induced the synthesis of both types of collagen. The DCF assay indicated oxidative stress similar to the control cells for most of the selected retraction agents. Experimental gels did not cause degradation of the cellular shape and morphology of the primary HGFs. The proposed experimental retraction gels in the present study demonstrated higher biocompatibility with primary HGFs, suggesting their use as clinical vasoconstrictive agents for the application of gingival retraction with minimal damage to periodontal tissues.

Modifications of Polymeric Membranes Used in Guided Tissue and Bone Regeneration.

Guided tissue/bone regeneration (GTR/GBR) is a widely used procedure in contemporary dentistry. To achieve the required results of tissue regeneration, soft tissues that reproduce quickly are separated from the slow-growing bone tissue by membranes. Many types of membranes are currently in use, but none of them fulfil all of the desired features. To address this issue, further research on developing new membranes with better separation characteristics, such as membrane modification, is needed. Many of the current innovative modified materials are still in the phase of in vitro and experimental studies. A collective review on new trends in membrane modification to GTR/GBR is needed due to the widespread use of polymeric membranes and the constant development in the field of dentistry. Therefore, the aim of this review was to present an overview of polymeric membrane modifications to the GTR/GBR reported in the literature. The authors searched databases, including PubMed, SCOPUS, Web of Science, and OVID, for relevant studies that were published during 1999-2019. The following keywords were used: guided tissue regeneration, membranes, coating, and modification. A total of 17 papers were included in this review. Furthermore, the articles were divided into three groups that were based on the type of membrane modification: antibiotic coating, ion-use modifications, and others modifications, thus providing an overview of current existing knowledge in the field and encouraging further research. The results of included studies on modified barrier membranes seem to be promising, both in terms of safety and benefits for patients. However, modifications result in a large spectrum of effects. Further clinical studies are needed on a large group of patients to clearly confirm the effects that were observed in animal and in vitro studies.

Changes in hardness of addition-polymerizing silicone-resilient denture liners after storage in artificial saliva.

STATEMENT OF PROBLEM: The hardness of silicone resilient denture liners was reported to be more stable than that of acrylic resin resilient denture liners. However, the changes in hardness of these materials in artificial saliva are unclear. PURPOSE: The purpose of this in vitro study was to evaluate changes in the hardness of addition-polymerizing silicone-resilient denture liners for long-term use after storage in artificial saliva. MATERIAL AND METHODS: Four addition-polymerizing silicone resilient denture liners were tested: GC Reline Soft, Elite Soft Relining, Megabase, and Mucopren Soft. All were long-term relining materials of the soft type. Fifteen disk-shaped specimens were prepared for each of the tested materials (40 mm in base diameter, 8 mm in thickness). Their initial hardness was assessed with a Shore A durometer, after which they were stored in artificial saliva at a temperature of 37°C. Hardness was examined after 7, 30, and 90 days. Statistical analysis was performed using parametric ANOVA for dependent and independent variables and Tukey honest significant difference (HSD) post hoc tests (α=.05). RESULTS: All resilient denture liners increased in hardness during the experiment. The change was least for Elite Soft Relining, and GC Reline Soft was the hardest material. Initially, Megabase and Mucopren Soft were significantly softer than the other 2 materials, but their hardness increased rapidly after the first 7 days of specimen conditioning, achieving values close to Elite Soft Relining. CONCLUSIONS: Within the limitations of the study, room temperature vulcanizing addition-polymerizing polyvinyl siloxanes of the soft type have different initial hardness, and this changes with storage time in artificial saliva at the temperature of the oral cavity.

Analysis of the electrolytically polished skeletal dentures surfaces using various nano- and microscopic technologies.

PURPOSE: The surface roughness of the dental restorations is significant to the denture plaque adhesion. METHODS: In this work, we present the complex analysis of the electropolished CoCrW alloy remanium® star (Dentaurum, Germany) samples with laserengraved fiducial marks performed using complementary set of micro- and nanoscopic techniques: optical profilometry (OP), atomic force microscopy (AFM), scanning electron microscopy (SEM) and focused ion beam (FIB) milling. RESULTS: Both mean and RMS roughness of the samples were reduced by electopolishing process, however, the results obtained using OP and AFM exhibited some discrepancies. This was caused by the relatively high local protruding defects developed on the processed surface. The cross-sections of the protrusions were made to analyze the cause of their formation as the EDS elemental content maps revealed that their composition was uniform. We also analyzed the local roughness in the smaller areas free from the defects. CONCLUSIONS: In that case, both OP and AFM techniques delivered the same results. Analysis of results showed that various methods used for the surface roughness evaluation have to be used simultaneously to obtain complete and true analysis of the technological CoCrW samples.

Spectrophotometric evaluation of 5-layer acrylic teeth hyperpigmentation caused by selected food colors: In vitro study.

BACKGROUND: Prosthetic treatment restores proper chewing function and facial aesthetics, and enhances the quality of life. The overall aesthetic result of the use of removable prostheses is correlated with the type of artificial teeth used and with the maintenance of aesthetic effect and color stability. OBJECTIVES: The aim of the study was to evaluate the formation and intensity of discoloration caused by the dyes present in selected 5-layer acrylic teeth. MATERIAL AND METHODS: The study material was a group of 90 5-layer acrylic teeth. Samples were immersed in black tea and dry red wine for 6 months. The control group was immersed in distilled water and consisted of 30 samples. The teeth were subjected to spectrophotometric examination at the start of the study, after 24 h, 7 days, 14 days, 1 month, 4 months, and 6 months. RESULTS: Among the teeth examined, in about 85% of the samples the color corresponded with the order. Teeth immersed in black tea became darker. From the 7th day to the 6th month, none of the samples changed their brightness. The teeth had the same degree of brightness. The teeth did not change tone during the experiment. Teeth immersed in dry red wine changed their shade to A starting on the 14th day, and by the 4th month all samples had changed shade to A or C. The 5-layer teeth had quite high shade stability until the 14th day of observation. In the control group, the teeth did not change tone and individual brightness changed more in the direction of brighter shades and less in the darker direction. In the study group, 93% of the samples did not change their brightness. CONCLUSIONS: Both black tea and dry red wine cause tooth discoloration, more intensely in the case of the 2nd fluid. Acrylic teeth with a 5-layer structure ensure good color stability over time. It improves the quality and aesthetics of the restorations used.

Electromyographic Analysis of Masticatory Muscles in Cleft Lip and Palate Children with Pain-Related Temporomandibular Disorders.

Aim: The aim of this study was to assess the electrical activity of temporalis and masseter muscles in children with cleft lip and palate (CLP) and pain-related temporomandibular disorders (TMD-P). Methods: The sample consisted of 31 CLP patients with a TMD-P (mean age 9.5 ± 1.8 years) and 32 CLP subjects with no TMD (mean age 9.2 ± 1.7 years). The children were assessed for the presence of temporomandibular disorders (TMD) using Axis I of the Research Diagnostic Criteria for TMD (RDC/TMD). Electromyographical (EMG) recordings were performed using a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany) in the mandibular rest position and during maximum voluntary contraction (MVC). Results: The rest activity of the temporalis and masseter muscles was significantly higher in TMD-P group compared with non-TMD children. A significant decrease in temporalis muscle activity during MVC was observed in TMD-P patients. There was a significant increase in the Asymmetry Index for temporalis and masseter muscle rest activity in the TMD-P group. Conclusion: Cleft children diagnosed with TMD-P have altered masticatory muscle activity, and this can affect their muscle function.

The bond shear strength of methacrylate materials used to reduce dental and alveolar undercuts.

BACKGROUND: The reduction of dental and alveolar undercuts on plaster models is an important issue in the process of planning partial and complete prostheses. In recent years, new materials such as methacrylate resins that can be used to reduce undercuts have emerged. Their great advantage is high temperature insensitivity and relatively high ease of use. OBJECTIVES: The study aimed at determining the factors that affect the shear bond strength, and which material can be better used at the laboratory stage of preparing the plaster model to facilitate the denture bearing area and reduce the traumatizing impact of the prosthesis. MATERIAL AND METHODS: In the study, 2 composite materials Block-Out Gel LC (VOCO GmbH, Cuxhaven, Germany) and LC Block-Out Resin (Ultradent Products Inc., South Jordan, USA) were used for tests on the Tewerock and Stodent plaster. Specimens consisted of 20 mm × 10 mm × 10 mm plaster blocks as a base, and composite cylinders of 3 mm diameter and 5 mm height, attached to the blocks. The base of the sample was combined with a composite cylinder in the Individo Light Box halogen lamp (VOCO GmbH, Cuxhaven, Germany). A total of 120 samples were studied. The shear bond strength (SBS) test was performed using the Hounsfield H5KS model HTE S/N D83281 fitted with a 5.000-N head using a cutting knife speed of 5 mm/ min. RESULTS: LC Block-Out Resin and Block-Out Gel LC materials deposited on class III plaster and polymerized at temperatures of up to 100°C had the best SBS (5.59 MPa and 4.0 MPa, respectively). Samples made of LC Block-Out Resin and class IV plaster showed no statistically significant differences between all the groups. Additional polymerization under 2.4 bar was the most effective in improving SBS among Block-Out Gel LC and class IV plaster samples. CONCLUSIONS: The results of the studies show that both the plaster type and the polymerization process have a significant effect on the SBS of light-cured methacrylate material to plaster.

The Setting Time of Polyether Impression Materials after Contact with Conventional and Experimental Gingival Margin Displacement Agents.

PURPOSE: The compatibility of chemical gingival margin displacement agents with polyether impression materials has not been determined. The aim of this study was to evaluate the setting time of polyether impression elastomers after contact with conventional and experimental gingival displacement agents. MATERIALS AND METHODS: The study compared the setting time of two polyether impression materials: medium body (Impregum Penta Soft) and light body (Impregum Garant L DuoSoft) after contact with 10 gingival displacement agents, including 5 conventional astringents (10%, 20%, and 25% aluminum chloride, 25% aluminum sulfate, and 15.5% ferric sulfate) and 5 experimental adrenergics (0.1% and 0.01% HCl-epinephrine, 0.05% HCl-tetrahydrozoline, 0.05% HCl-oxymetazoline, and 10% HCl-phenylephrine). As many as 120 specimens (60 light body and 60 medium body) were mixed with 20 µl of each of 10 gingival displacement agents, and the time to achieve maximum viscosity was measured with a viscometer. The setting times of these specimens were compared with the control group of 12 specimens, which were polymerized without contact with the displacement agents. The experiments were performed in two environments: 23°C and 37°C (± 0.1°C). Individual and average polymerization time compatibility indices (PTCI) were calculated. Data were analyzed by 2-way ANOVA (α = 0.05). RESULTS: The evaluated chemical displacement agents from both groups changed the setting time of light- and medium-body PE. The negative individual PTCI values achieved astringent (20% aluminum chloride) with two PE in both temperature environments. The average PTCI values of the experimental displacement agents at laboratory and intraoral temperatures were significantly higher than the conventional agents. CONCLUSIONS: The present findings suggest that experimental retraction agents can be recommended clinically as gingival margin displacement agents with minimal effects on the setting time of medium- and light-body polyether impression materials; however, direct contact of chemical displacement agents and polyether impression materials can be avoided.

The assessment of prosthetic needs of ESRD patients and the general population in Poland on the basis of the Eichner classification and teeth number: A brief, preliminary report.

BACKGROUND: End-stage renal disease (ESRD) patients are considered as a group of high risk of oral cavity diseases. One of the determinants of alveolar bone loss and increased teeth mobility in ESRD patients might be the bone abnormalities associated with chronic kidney disease-mineral and bone disorder (CKD-MBD). OBJECTIVES: The aim of the study was to compare the general health condition, number and location of teeth in a group of ESRD patients with the group of peers from general population and revealing the risk factors of tooth loss. MATERIAL AND METHODS: The ESRD group included 63 patients, 23 females and 40 males, undergoing dialysis with a mean age of 62.4 ± 15.6. The general population sample consisted of 37 people, 20 females and 17 males, applying for general practitioner visit, with a mean age of 65.5 ± 11.1. All the participants were using just public health care insurance. The data analysis was based on anamnesis, history of CKD, selected biochemical parameters of blood tests and clinical examination. RESULTS: There was no statistical difference in the prosthetic needs of patients undergoing dialysis and the general population. In both groups the situation is alarming. CONCLUSIONS: The new procedures are needed to develop complex health care for ESRD and general population patients, emphasizing prophylaxis of tooth-loss and prosthetic treatment in order to maintain good level of life quality.

The analysis of cytotoxicity of an experimental preparation used for the reduction of dentin hypersensitivity.

BACKGROUND: The problem of effective treatment of dentin hypersensitivity is still valid and not fully resolved. OBJECTIVES: The aim of the study was to evaluate the potential toxicity against body tissues of an experimental preparation which is supposed to reduce dentin hypersensitivity and to compare it to a commercial formulation Seal & Protect (Dentsply) by means of measuring the activity of mitochondrial dehydrogenases (the MTT assay). MATERIAL AND METHODS: The study used an original protective formulation which is supposed to eliminate hypersensitivity of dentin. A commercial preparation Seal & Protect (Dentsply) was used as the comparative material. Cytotoxic activity of the tested preparations (experimental and commercial) on murine lymphocyte cells CCL-1™ (NCTC clone 929) was determined in indirect contact with the use of the MTT test that measured the activity of the mitochondrial dehydrogenase enzyme. RESULTS: A comparison of the results obtained in the MTT assay for the commercial preparation Seal & Protect (Dentsply) and the experimental formulation indicates that an experimental formulation has considerably lower cytotoxicity before polymerization, when compared to the commercial formulation, regardless of its dilution. However, after the polymerization of the commercial formulation was completed, its parameters improved significantly, especially for higher dilution values (1 : 10 and 1 : 15). Results for the experimental formulation are higher, particularly for the dilution value of 1 : 5. The overall summary of the results obtained from the MTT assay for the commercial preparation Seal & Protect (Dentsply) and the experimental formulation indicates that the experimental formulation had a significantly lower cytotoxicity before polymerization in comparison with the commercial formulation, regardless of dilution. CONCLUSIONS: Estimating the biocompatibility of a given material is not simple, and measurement methods are rapidly evolving, as more and more is known about the interaction between dental materials and oral tissues, and also as a result of improvements in testing techniques.