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Permeability of latex gloves after contact with dental materials.

The use of latex examination gloves in the dental office has become the standard of care. However, the effectiveness of gloves as a barrier after coming into contact with specific dental materials is still uncertain. To examine the effects of dental materials is still uncertain. To examine the effects of dental materials on latex, 100 latex examination glove finger tips were divided into 10 groups. Each group was manipulated in a different dental material for 15 minutes. Permeability was detected by the passage of herpes virus across the latex membrane, rinsed from the inner glove surface and titrated onto Vero cells. Significant virus leakage was discovered in gloves treated with acrylic monomer, chloroform, and orange solvent. Little virus leakage was noted in bleach, soap, and 30% phosphoric acid etchant treated gloves, and no virus leakage was found with composite resin, ethanol, formocresol, and water treated gloves. These data were supported with scanning electron micrographs taken of the treated glove samples and comparing with the controls. When certain dental materials are manipulated while wearing gloves, irreversible damage to the material occurs and may increase the practitioner's exposure to pathogens.

Animals↗

Dental materials in pediatric dentistry.

Dental materials for the restorative armamentarium in pediatric dental care continue to improve in esthetics and function. This review describes the application of some contemporary materials and concepts. Fluoride-releasing glass ionomers are appropriate for use as luting cements and as liners and bases. The glass ionomer cements have minimal solubility in oral fluids and possess the capability of inhibiting secondary caries. Amalgam and composite resin are effective for class II restorations, although amalgam placement is considerably less time consuming and less technique sensitive. Composite resins, particularly more highly filled resins, are appropriate for anterior restorative care. The use of ceramic glass inserts may provide strength and decrease restorative time for composite resin restorations in the future. When planning treatment for pediatric dental patients, each patient and restorative material to be used should be evaluated on an individual basis, in order to provide appropriate care within each material's limitations. Pediatric restorative dentistry involves the use of many materials. As materials improve in durability, strength, esthetics, and anticariogenic properties, the concepts of contemporary pediatric restorative dentistry change. Certainly, the traditional principles of restorative dentistry remain practical and significant in the practice of dentistry. Although these traditional concepts are extremely relevant, newer materials allow for modifications to be made during treatment planning in restorative dentistry. This review presents some newer materials and concepts and their applications in current pediatric restorative dentistry.

Child↗

Summaries of clinically relevant studies of dental materials from the 1995 meeting of the American Association for Dental Research.

The object of this review is to provide clinical research information. Each year, several hundred dental materials research papers are presented at the AADR meeting. For additional information about these studies, consult the abstracts published in J Dent Res 1995;74(special issue):12-257. Papers presented to the AADR Dental Materials Group are published in microfilm and microfiche, available in dental school libraries.

Composite Resins↗

Biological testing of dental materials: development of national and international standards.

Testing of dental materials helps to ensure that they are of satisfactory quality. Most standardized testing programs have focused on the physical, chemical, and mechanical properties of the materials, and started at the National Bureau of Standards, USA, in 1919. The need for biological evaluation of dental materials became evident after some material-related adverse incidents. The first document concerning standardized testing of the biological properties of dental materials was published by the American Dental Association in 1972. During the last twenty-five years, increased attention has been focused on the evaluation of biological properties by standardized testing. The development of standards concerning biological testing of dental materials since 1972 at the national and international level is described.

American Dental Association↗

Skin and mucosal reactions associated with dental materials.

The selection of dental materials for specific treatment purposes is primarily based on their physical properties. The composition of materials available indicates that there is the potential for adverse biological effects. The amounts of substances released are usually too low to cause any overt systemic toxic effects. However, many of the chemicals used in dentistry are irritating and may cause local damage. Also, in reactions mediated via the amplifying mechanisms of the immune system, small amounts may lead to clinical manifestations of allergic contact dermatitis and urticaria. A special problem in the diagnosis of adverse events occurs when intraoral exposure leads to generalized urticarial reactions. Due to a low level of suspicion, extraoral reactions are rarely associated with dental treatment modalities. Occupational dermatoses represent a serious problem, especially the development of an allergy to constituents of the resin-based filling materials and adhesives. The monomers of resin-based materials are volatile and penetrate latex and vinyl gloves easily. Allergic contact dermatitis related to resin-based materials may be occupationally disabling.

Adhesives↗

In vivo validation of the historical in vitro thermocycling temperature range for dental materials testing.

In dental research, restorative materials have been regularly subjected to alternating in vitro thermal stress in investigations since the 1950s, in order to simulate in vivo alternating temperature stress and to artificially stress them in vitro. The provocation temperature is mostly 5 degrees C for cold provocation, and 55 degrees C for hot provocation. These temperatures are determined quite arbitrarily based on very few examinations in vivo. Extensive temperature data for the approximal space of teeth, which is decisive for the success of fillings adhesively attached to dentin, has so far not been addressed. The objective of this study was to examine the interproximal temperature characteristics created in the space of all teeth in vivo with thermal alternating stress, and therefore to validate the in vitro standardized thermal alternating stress of 5-55 degrees C. Fifteen study participants with healthy teeth were used to determine the temperature in each inter-dental space, resulting from hot/cold provocation in the upper and lower jaw, from the central incisor to the second molars. This was performed by a thermal element (cable sensor GTF 300, Greisinger Electronic GmbH, Regenstauf, Germany). The temperature sensor was attached with dental floss into the interproximal space and the temperature was recorded by the computer. The participants in the pilot test had to state when they were able to sip an 85 degrees C hot drink. That particular temperature value was taken for hot provocation as maximum temperature reference. Cold ice water (0 degrees C) was used for cold provocation as minimum temperature reference. The respective recordings with a total of 14 measurements for each individual were performed simultaneously in the upper and lower jaw. The study participants were to start with hot provocation, followed by cold provocation. This cycle was repeated at least once with an individual dwell time. The highest recorded approximal space temperature was 52.8 degrees C in the lower jaw, between the first and the second premolar. The lowest temperature of 13.7 degrees C was recorded in two participants in the upper jaw, between the 1st and 2nd incisor, and between the two central incisors. The mean of the maximum temperatures was 43.8+/-3.7 degrees C, and the mean of the minimum temperatures 24.2+/-4.6 degrees C. The mean initial temperature was 35.2+/-1.3 degrees C. None of the recordings reached either the upper threshold (55 degrees C) or the lower threshold (5 degrees C). This study showed that the actual thermal stress in the interproximal space of teeth is slightly lower than the one used in in vitro examinations. For class II cavities, most of the alternating temperature stress limits selected at 5-55 degrees C cover the actually occurring temperature interval quite well.

Adolescent↗

Restorative dental materials: scanning electron microscopy and x-ray microanalysis.

Restorative dental materials include the materials used to repair damaged teeth and/or replace missing teeth. The definition could be extended to include a much broader group of dental materials, but this paper concentrates only on those materials used to restore the crown portion of damaged teeth. Auxiliary materials, materials for removable denture prostheses, and root canal materials are excluded. Progress and recent research utilizing SEM (Scanning Electron Microscopy), EDS (Energy Dispersive Spectroscopy), and some related methods are presented for the following dental materials: dental amalgam, enamel and dentin bonding agents, dental composites, dental cements, casting alloys for crowns and bridges, and ceramic-metal and ceramic restorative materials. In addition to the basic characterization of these materials by SEM/EDS techniques, examples of replication methods for SEM study of restorative materials in situ are discussed. Some examples are also presented in the direct use of SEM/EDS for characterization of changes and degradation of restorative materials which occur during clinical use.

Dental Materials↗

The radiopacity of glass ionomer dental materials.

Although some glass ionomer dental materials are described as radiopaque by the manufacturer, it is rare for the actual degree of radiopacity to be specified. Using a technique previously described for measurement of the radiopacity of enamel, dentine and composite resin dental materials, the radiopacity of a number of glass ionomer materials, including restorative, lining and luting cements, was determined.

Dental Cements↗

Myofibroblasts in connective tissue capsules around implanted dental materials.

For testing the biocompatibility of dental materials in an experimental animal model the capsular tissues around the implanted dental materials were examined light and electron microscopically. The exudative inflammation and fibrosis at different times after implantation were thought to be the indicators of the degree of the compatibility. Starting from the knowledge of the occurrence of myofibroblasts in reparative granulation tissue we looked for such cells in the capsular tissues. Myofibroblasts were especially found at three weeks after onset of the experiments. Structural peculiarities of this fibroblast modulation are emphasized. Myofibroblasts are considered as an essential link between the early exudative reaction and the late fiber formation in tissue reactions after mechanical injury.

Animals↗

International distribution of dental materials publications and patents.

International patterns of research and development in the field of restorative dental materials were examined with data on publications (1981-85) and patents (1979-88). It was found that United States-based authors produced approximately one-half of all dental materials journal articles published worldwide, while US inventors had nearly the same share of the US dental materials patents. During the periods studied, the share of US patents in dental materials awarded to US inventors declined, while the share of US patents awarded to Japanese inventors rose. The role of the United States in research (as measured by journal articles) remained stable. Nations differed in the degree to which their researchers specialized in particular research areas. US-based authors and inventors were relatively over-represented in prosthetic materials and under-represented in dental cements, an area in which the British and the Japanese concentrated more of their activity. There was some, but not complete, agreement in the patterns of national specialization as indexed by patent and publication data. When dental materials data were compared with data for broader fields of science and technology, important differences were found. For publications, US-based authors displayed greater dominance in dental materials than in the fields of dentistry, chemistry, and materials science. US-based inventors' share of US dental materials patents was smaller than their share of all US patents. These analyses demonstrated that it was possible to use indicators derived from publication and patent data files to conduct insightful studies of a discrete specialty of science and technology.

Databases, Bibliographic↗

The influence of surface area on the in vitro cytotoxicity of a range of dental materials.

In the toxicity testing of dental materials the quantity of material used may have a profound influence on the biological response obtained. This was investigated in vitro by assessing the cytotoxicity of equal volumes of nine materials in artificial cavities of three different diameters, chosen to cover the range found in vivo. With seven materials there was a significant increase in toxicity with increasing surface area. The pattern of response of different materials within specific groups was fairly uniform. The degree of toxicity of the test materials relative to controls was also investigated. From the data obtained it is apparent that the maximum cavity diameter appropriate for the material under test must be considered when evaluating the toxicity of dental materials.

Animals↗

Dental materials: 1995 literature review.

This critical review of the published literature on dental materials for the year 1995 has been compiled by the Dental Materials Panel of the United Kingdom. It continues the series of annual reviews started in 1973 and published in the Journal of Dentistry. Emphasis has been placed upon publications which report upon the materials science or clinical performance of the materials. The review has been divided by accepted materials classifications (fissure sealants, glass polyalkenoate cements, resin composites, dentine bonding, dental amalgam, endodontic materials, casting alloys, investment materials, resin-bonded bridges and ceramo-metallic restorations, all ceramic restorations, denture base and soft lining materials, impression materials, dental implants, orthodontic materials and biomechanics). Three hundred and thirty articles published in 68 titles have been reviewed.

Biomechanical Phenomena↗

In vitro evaluation of dental materials.

Biocompatibility has been described as the ability of a material to perform with an appropriate host response in a specific application. Appropriate host response means no (or a tolerable) adverse reaction of a living system to the presence of such a material. An adverse reaction may be due to the toxicity of a dental material. Therefore toxicity may be regarded as one reason for nonbiocompatibility of a dental material. The toxicity of a dental material can be evaluated by in vitro tests, animal experiments and clinical trials. There exists a variety of different in vitro test methods. The most widely used biological systems for toxicity screening of dental materials are cell cultures. Cell cultures for toxicity screening of dental materials are valuable tools for understanding their biological behavior, if the limitations of the methods are taken into consideration, especially concerning the interpretation of the results. Further research should concentrate on better simulations of the in vivo situation in cell cultures. In this review the applications of various cell culture methods to evaluate the cytotoxicity of a wide range of dental materials, e.g. metals, alloys, polymers and cements, are described.

Animals↗

[Mouth diseases and dental materials: potential for study with cytofluorometry].

BACKGROUND: The potential dental materials have of inducing mouth diseases is well known, and various methods have been developed to investigate this phenomenon. Among these there are histological studies of the pulp and periodontium exposed to dental materials, both in vivo and in vitro in humans and animals. Other studies are based on the clinical observation of the effects induced by dental materials. Aim of the paper is to evaluate the use of flow cytometry to analyse crevicular fluid to study its content in terms of inflammatory cells and inflammation mediators. METHODS: Samples of crevicular fluid were collected by aspiration using a bevelled needle mounted on a 5 ml syringe from patients without periodontitis and with periodontitis and multiple heterogeneous dental restorations. This method was adopted since it allows to place the cells of the fluid in suspension. Part of the fluid was analysed by cytology and part by flow cytometry. RESULTS: In the patients without periodontal disease cytological examination revealed the presence of desquamated epithelial cells and colonies of cocci, rods and spirochaetae. In the patients with periodontal disease the same examination revealed, besides the above, the presence of inflammatory cells. Flow cytometry confirmed the findings of cytological examination, thus proving to be an effective method for studying crevicular fluid. CONCLUSIONS: This method allows to identify specific inflammatory cells or mediators of inflammation in crevicular fluid and may therefore prove to be very useful in the study of alterations induced by some dental materials at the level of the gingival sulcus.

Adult↗

Dental materials: 1997 literature review.

This review of the published literature on dental materials for the year 1997 has been compiled by the Dental Materials Panel of UK. It continues a series of annual reviews started in 1973. Emphasis has been placed upon publications, which report upon the materials science or clinical performance of the materials. The review has been divided by accepted materials classifications (fissure sealants, glass polyalkenoate cements, dentine bonding, dental amalgam, endodontic materials, casting alloys, ceramometallic restorations and resin-bonded bridges, ceramics, denture base resins and soft lining materials, impression materials, dental implant materials, orthodontic materials, biomechanics and image processing, resin composites, and casting investment materials and waxes). Three hundred and thirty three articles have been reviewed.

Dental Materials↗

Genotoxicity of dental materials.

This study was performed to characterize the (possible) DNA-damaging properties of dental materials and to identify specific compounds that contribute to this genotoxicity. For screening, three tests that assay for different aspects of genotoxicity (i) the bacterial umu-test; (ii) the eucaryotic DNA synthesis inhibition test; and (iii) the in vivo alkaline filter elution technique were chosen. This investigation gives several lines of evidence that most dental materials tested (14 chemical monosubstances present in dental devices and 7 extracts of dental materials) yield 'positive' results in at least one of the genotoxicity tests, however, with effects ranging from 'borderline' to 'strong positive'. The extracts of the widely used dental materials Vitrebond and AH26 elicited clear concentration-related genotoxic responses in all test systems. On the basis of these data and public concern, more attention has to be given to local or systemic complications which may be associated with the use of dental materials.

Animals↗