Apical periodontitis is produced in the majority of cases by intraradicular infection. Treatment consists in the elimination of the infectious agents by endodontia. Even when carrying out a correct cleansing and filling of canals, it is possible that periapical periodontitis will persist in the form of an asymptomatic radiolucency, giving rise to the post-endodontic periapical lesion.
Fluoride has long been known to influence the activity of various enzymes in vitro. Later it has been demonstrated that many effects primarily attributed to fluoride are caused by synergistic action of fluoride plus aluminum. Aluminofluoride complexes have been widely used as analogues of phosphate groups to study phosphoryl transfer reactions and heterotrimeric G proteins involvement. A number of reports on their use have appeared, with far-reaching consequences for our understanding of fundamental biological processes. Fluoride plus aluminum send false messages, which are amplified by processes of signal transduction. Many investigations of the longterm administration of fluoride to laboratory animals have demonstrated that fluoride and aluminofluoride complexes can elicit impairment of homeostasis, growth, development, cognition, and behavior. Ameliorative effects of calcium, vitamins C, D, and E have been reported. Numerous epidemiological, ecological, and clinical studies have shown the effects of fluoride on humans. Millions of people live in endemic fluorosis areas. A review of fluoride interactions from molecules to disease is necessary for a sound scientific assessment of health risks, which may be linked to the chronic intake of small doses of fluoride and aluminum from environmental and artificial sources.
The clinical manifestations of contact allergic dermatitis to dental materials are not uniform. This study was performed to detect the frequent allergens in the dental series associated with contact dermatitis and to define the causal relationship between the different allergens and the relevant clinical presentations. Between the years 2000 and 2004, 134 patients, aged 20-80 years, were patch tested. 121 patients were included in the study. The most frequent oral manifestations were cheilitis and perioral dermatitis (25.6%), burning mouth (15.7%), lichenoid reaction (14.0%), and orofacial granulomatosis (10.7%). 18 (14.9%) patients were dental personnel, all of whom suffered from hand dermatitis. The common allergens detected included goldsodiumthiosulphate (14.0%), nickel sulfate (13.2%), mercury (9.9%), palladium chloride (7.4%), cobalt chloride (5.0%), and 2-hydroxyethyl methacrylate (5.8%). Positive reactions to metals were frequent in all the different clinical variants, and no specific association between a specific clinical presentation and a particular allergen was found. Allergy to mercury was not a significant factor contributing to the pathogenesis of oral lichenoid reactions. However, a strong association with contact allergy to mercury in dental fillings was found in 2 patients with orofacial granulomatosis.
Apical periodontitis is a chronic inflammatory disorder of periradicular tissues caused by aetiological agents of endodontic origin. Persistent apical periodontitis occurs when root canal treatment of apical periodontitis has not adequately eliminated intraradicular infection. Problems that lead to persistent apical periodontitis include: inadequate aseptic control, poor access cavity design, missed canals, inadequate instrumentation, debridement and leaking temporary or permanent restorations. Even when the most stringent procedures are followed, apical periodontitis may still persist as asymptomatic radiolucencies, because of the complexity of the root canal system formed by the main and accessory canals, their ramifications and anastomoses where residual infection can persist. Further, there are extraradicular factors — located within the inflamed periapical tissue — that can interfere with post-treatment healing of apical periodontitis. The causes of apical periodontitis persisting after root canal treatment have not been well characterized. During the 1990s, a series of investigations have shown that there are six biological factors that lead to asymptomatic radiolucencies persisting after root canal treatment. These are: (i) intraradicular infection persisting in the complex apical root canal system; (ii) extraradicular infection, generally in the form of periapical actinomycosis; (iii) extruded root canal filling or other exogenous materials that cause a foreign body reaction; (iv) accumulation of endogenous cholesterol crystals that irritate periapical tissues; (v) true cystic lesions, and (vi) scar tissue healing of the lesion. This article provides a comprehensive overview of the causative factors of non-resolving periapical lesions that are seen as asymptomatic radiolucencies post-treatment.
The precautionary principle calls for preventive actions in the face of uncertain information about risks. It serves as a compass to better guide more health-protective decisions in the face of complex risks. Applying precaution requires thinking more broadly about risks, taking an interdisciplinary approach to science and policy, and considering a wide range of alternatives to potentially harmful activities. While often criticized as antiscientific, the precautionary principle represents a challenge to scientists and public health professionals to develop newer and more effective tools for characterizing and preventing complex risks, in addition to being more explicit about uncertainties. This article examines the role and application of precaution in the context of dental practice, where activities that may convey risks also have public health benefits, and risk trade offs are a possibility. We conclude that the precautionary principle is not at odds with, but rather complements evidence-based practice in situations of scientific uncertainty and complex risks.
This report presents the committee’s review of the scientific basis of EPA’s MCLG and SMCL for fluoride, and their adequacy for protecting children and others from adverse health effects. The committee considers the relative contribution of various sources of fluoride (e.g., drinking water, food, dental-hygiene products) to total exposure, and identifies data gaps and makes recommendations for future research relevant to setting the MCLG and SMCL for fluoride. Addressing questions of economics, risk-benefit assessment, or water-treatment technology was not part of the committee’s charge.
In dentistry, a variety of potentially allergenic metals are used, such as mercury, palladium, nickel, gold, chromium, cobalt and other metals. This paper describes a diagnostic approach from a dentist’s point of view, which enables analysis of metals in a patient’s oral cavity. If metal allergy is suspected, a micro analysis can be used to determine which metals are present in the restorations. When the exact composition of the dental materials is known, the patient can be tested in vivo (patch test) and/or in vitro (lymphocyte proliferation test) to reveal sensitization. Two patients with nickel allergy are described where removal of nickel-containing materials (bridge and orthodontic wire) resulted in the marked alleviation of symptoms and improvement of health. Finally, if allergy to specific metals has been established, the restorations containing the implicated metals should be removed to discontinue the exposure and thus facilitate the patient’s health.
The objective of this study was to determine the concentration changes of 13 elements in erythrocytes and plasma after the removal of dental amalgam and other metal alloys. Blood samples from 250 patients were collected, separated into erythrocytes and plasma, and analyzed by inductively coupled plasma-mass spectrometry. The 250 patients were divided into 3 groups (Negative, Zero, and Positive) depending on their estimation of quality of life in an earlier study. Magnesium in plasma, selenium and mercury in plasma, and erythrocytes showed decreased concentrations after amalgam removal in all groups (p < 0.05). Titanium in plasma, copper in plasma, and erythrocytes and zinc in plasma exhibited decreased concentrations after amalgam removal in the Negative and Positive groups (p < 0.05). Silver in plasma and gold in erythrocytes decreased in the Zero and Positive groups after amalgam removal (p < 0.05). Copper in erythrocytes and silver and gold in plasma showed higher concentrations after amalgam removal in the Negative compared to the Positive group (p < 0.05), suggesting that patients in the Negative group excrete metals slowly. Moreover, the cobalt levels in plasma were lowest in the Negative group and only this group showed a significant increase in vitamin B12 levels in blood after amalgam removal.
OBJECTIVES:
This study was carried out to investigate the potential of titanium to induce hypersensitivity in patients chronically exposed to titanium-based dental or endoprosthetic implants.
METHODS:
Fifty-six patients who had developed clinical symptoms after receiving titanium-based implants were tested in the optimized lymphocyte transformation test MELISA against 10 metals including titanium. Out of 56 patients, 54 were patch-tested with titanium as well as with other metals. The implants were removed in 54 patients (2 declined explantation), and 15 patients were retested in MELISA.
RESULTS:
Of the 56 patients tested in MELISA, 21 (37.5%) were positive, 16 (28.6%) ambiguous, and 19 (33.9%) negative to titanium. In the latter group, 11 (57.9%) showed lymphocyte reactivity to other metals, including nickel. All 54 patch-tested patients were negative to titanium. Following removal of the implants, all 54 patients showed remarkable clinical improvement. In the 15 retested patients, this clinical improvement correlated with normalization in MELISA reactivity.
CONCLUSION:
These data clearly demonstrate that titanium can induce clinically-relevant hypersensitivity in a subgroup of patients chronically exposed via dental or endoprosthetic implants.
The aim of this investigation was to determine the influence of fluoride in certain mouthwashes on the risk of corrosion through galvanic coupling of orthodontic wires and brackets. Two titanium alloy wires, nickel-titanium (NiTi) and copper-nickel-titanium (CuNiTi), and the three most commonly used brackets, titanium (Ti), iron-chromium-nickel (FeCrNi) and cobalt-chromium (CoCr), were tested in a reference solution of Fusayama-Meyer artificial saliva and in two commercially available fluoride (250 ppm) mouthwashes, Elmex and Meridol. Corrosion resistance was assessed by inductively coupled plasma-atomic emission spectrometry (ICP-MS), analysis of released metal ions, and a scanning electron microscope (SEM) study of the metal surfaces after immersion of different wire-bracket pairs in the test solutions. The study was completed by an electrochemical analysis. Meridol mouthwash, which contains stannous fluoride, was the solution in which the NiTi wires coupled with the different brackets showed the highest corrosion risk, while in Elmex mouthwash, which contains sodium fluoride, the CuNiTi wires presented the highest corrosion risk. Such corrosion has two consequences: deterioration in mechanical performance of the wire-bracket system, which would negatively affect the final aesthetic result, and the risk of local allergic reactions caused by released Ni ions. The results suggest that mouthwashes should be prescribed according to the orthodontic materials used. A new type of mouthwash for use during orthodontic therapy could be an interesting development in this field.