adam, Author at IAOMT Library

A comparative study of fluoride-releasing adhesive resin materials.

One of the most important and exciting properties of recently introduced dental restorative materials is their ability to release fluoride ions, as this has several advantageous effects on tooth structures. They have been extensively used as fluoride-releasing filling and luting materials. Recently, fluoride-releasing adhesive resins and fluoride-releasing adhesive resin cement have been developed and introduced for clinical use. The purpose of this study was to evaluate the fluoride release from these adhesive resins and the fluoride uptake by both enamel and dentin, as well as the acid-resistance of these tooth structures. Based on our results, we conclude that fluoride-releasing adhesive resins and luting cements are useful for the prevention of initial or secondary caries, especially along the margins of restorations.

By Han L, Edward C, Okatmoto A, Iwaku M.|2018-07-23T17:05:20+00:00January 1st, 2002|Fluoride|

The mercury burden in waste water released from dental clinics.

The aim of this study was to estimate mercury burden in waste water samples collected during one working day in 27 dental clinics. The samples were subjected to authorized analysis using the technique of QS-IE Enhanced Cold Vapour Mercury Analyzer to estimate the amount of mercury discharged. The mean value of mercury discharged was 2.49 parts per billion (ppb) for the clinics equipped with amalgam separators and 94.75 ppb for the clinics without amalgam separators. Some of the small amalgam particles released when new fillings are placed or during removal of old restorations form a sediment in tubes and drains. The remaining particles are carried with the waste water stream to the local purifying plant. If threshold values for heavy metal content including mercury are exceeded, the sludge is not allowed to be recycled as fertiliser. Installation of an approved amalgam-separating apparatus in dental clinics is recommended so as to reduce considerably the discharge of mercury into waste water.

By al-Shraideh M, Al-Wahadni A, Khasawneh S, al-Shraideh MJ.|2018-07-18T16:34:54+00:00January 1st, 2002|Mercury|

Fluoroquinolones and risk of Achilles tendon disorders: case-control study.

Fluoroquinolones have been associated with tendon disorders, usually during the first month of treatment,1–5 but the epidemiological evidence is scanty. We did a nested case-control study among users of fluoroquinolones in a large UK general practice database to study the association with Achilles tendon disorders.

By Van der Linden PD, Sturkenboom MC, Herings RM, Leufkens HG, Stricker BC.|2018-08-03T15:12:57+00:00January 1st, 2002|Fluoride|

Validity of MELISA® for metal sensitivity testing

Platelet-rich fibrin (PRF) therapy has been widely applied in regenerative dentistry, and PRF preparation has been optimized to efficiently form fibrin clots using plain glass tubes. Currently, a shortage of commercially available glass tubes has forced PRF users to utilize silica-coated plastic tubes. However, most plastic tubes are approved by regulatory authorities only for diagnostic use and remain to be approved for PRF therapy. To clarify this issue, we quantified silica microparticles incorporated into the PRF matrix. Blood samples were collected into three different brands of silica-containing plastic tubes and were immediately centrifuged following the protocol for advanced-PRF (A-PRF). Advanced-PRF-like matrices were examined using a scanning electron microscope (SEM), and silica microparticles were quantified using a spectrophotometer. Each brand used silica microparticles of specific size and appearance. Regardless of tube brands and individual donors, significant, but not accidental, levels of silica microparticles were found to be incorporated into the A-PRF-like matrix, which will be consequently incorporated into the implantation sites. Presently, from the increasing data for cytotoxicity of amorphous silica, we cannot exclude the possibility that such A-PRF-like matrices negatively influence tissue regeneration through induction of inflammation. Further investigation should be performed to clarify such potential risks.

By Valentine-Thon E, Schiwara HW.|2020-01-30T01:42:05+00:00January 1st, 2002|Mercury|

Laboratory evaluation of amalgam separators.

Background: Amalgam in dental wastewater is receiving increasing scrutiny from regulators because of national, state and local initiatives to reduce or virtually eliminate the discharge of mercury and mercury-containing items into the environment. Amalgam separators are considered to be one means of reducing the amount of amalgam that dental offices discharge into sewers. The purpose of this study was to evaluate the amalgam removal efficiency of commercially available amalgam separators and the total mercury concentration in the effluent from laboratory testing.

Methods: The authors evaluated the amalgam removal efficiency of 12 amalgam separators according to International Organization for Standardization, or ISO, Standard 11143 for Amalgam Separators. Total mercury concentration in the effluent was calculated using the mass of amalgam particles larger than 1.2 micrometers and the volume of effluent, together with U.S. Environmental Protection Agency, or EPA, Method 245.1 for amalgam particles smaller than 1.2 microm. Total dissolved mercury also was determined.

Results: The results show that all 12 amalgam separators exceeded the ISO 11143 requirement of 95 percent amalgam removal efficiency. Statistical differences were found in the efficiencies of the separators. Both the total mercury concentration and total dissolved mercury concentration in the effluent demonstrated large variations.

Conclusions and clinical implications: This laboratory evaluation shows that amalgam separators removed at least 96.09 percent of the amalgam in samples with particle-size distribution as specified in ISO 11143. Total mercury concentration and total dissolved mercury concentration in the effluent varied widely for each amalgam separator. Additional research is needed to develop test methods to evaluate the efficiency of amalgam separators in removing small amalgam particles, colloidal amalgam particles and ionic mercury in solution.

By Fan PL, Batchu H, Chou HN, Gasparac W, Sandrik J, Meyer DM|2020-12-21T01:02:22+00:00January 1st, 2002|Mercury|

Particle versus mercury removal efficiency of amalgam separators.

OBJECTIVE:
The intent of this project was to evaluate the efficiency of three commercial amalgam separators based on mercury and particle removal.

METHODS:
Dental wastewater samples were collected from a 54-chair dental clinic and a one chair private dental office. Atomic absorption spectrometry was used to measure mercury, and a laser diffractometer method to determine the particle size distributions.

RESULTS:
The mercury removal efficiency of the three units ranged from 26.5 to 61.8% for the 54-chair clinic and from 80.8 to 94.7% for the one chair office. Following treatment, the particle size range of the effluent was 8.3-19.2 microm for the 54-chair office and 27.5-41.4 microm for the one-chair clinic. For particle samples based on the silver-copper and copper standards, the three amalgam separators had a particle removal efficiency ranging from 92.3 to 99.9%. The initial particle size distributions for these samples were all under 100 microm.

CONCLUSIONS:
The efficiency of the amalgam separators is influenced by the initial concentration of the dental wastewater, the physical setup of the discharge system before the dental wastewater reaches the separators, and the addition of chemicals to the dental wastewater. In addition, it is likely that assessment of efficiency based on particle removal by weight may not be as effective as removal based on concentration.

By Drummond JL, Liu Y, Wu TY, Cailas MD.|2018-07-20T00:15:18+00:00January 1st, 2002|Mercury|

Epidemiology of contact allergy in adults.

BACKGROUND:

We aimed to determine the prevalence of contact sensitization in the general population and to investigate associations with important sociodemographic and medical characteristics.

METHODS:

Within a population-based nested, case-control study in Germany, we performed patch tests with 25 standard allergens in 1141 adults (50.4% female, age median 50 years). Additional information was obtained by a dermatologic examination, a standardized interview, and blood analysis.

RESULTS:

At least one positive reaction was exhibited by 40.0% of the subjects, with reactions most frequently observed to fragrance mix (15.9%), nickel (13.1%), thimerosal (4.7%), and balsam of Peru (3.8%). Women were sensitized more often than men (50.2% vs 29.9%, OR 2.36, CI 1.84-3.03), and this was also significant for fragrance mix, nickel, turpentine, cobalt chloride, and thimerosal. Contact sensitization was more frequent in subjects who reported adverse skin reactions (53.8% vs. 32.6%; OR 2.41, CI 1.85-3.14), and this was particularly true for sensitization to nickel (45.5% vs 8.8%, OR 8.64, CI 5.67-13.17) and fragrance mix (29.0% vs 14.0%, OR 2.51, CI 1.60-3.91) and the corresponding intolerance of fashion jewelry and fragrances. Contact sensitization decreased with increasing degree of occupational training (unskilled 45.9%, apprenticeship 40.1%, technical college 40.4%, and school of engineering 12.5%; P=0.023; trend test P=0.042). Significant associations of contact sensitization and presence of allergen-specific IgE antibodies, atopic eczema, or psoriasis were not observed. Frequency estimates for the general adult population based on these findings were 28.0% for overall contact sensitization and 11.4% for fragrance mix, 9.9% for nickel, and 3.2% for thimerosal.

CONCLUSIONS:

It is concluded that contact allergy is influenced by sociodemographic parameters and plays an important role in the general population.

By Schäfer T, Böhler E, Ruhdorfer S, Weigl L, Wessner D, Filipiak B, Wichmann HE, Ring J.|2020-01-27T23:29:13+00:00January 1st, 2001|Other|

Effects of four Ni–Ti preparation techniques on root canal geometry assessed by micro computed tomography.

AIM:

The aim of this study was to compare the effects of four preparation techniques on canal volume and surface area using three-dimensionally reconstructed root canals in extracted human maxillary molars. In addition, micro CT data was used to describe morphometric parameters related to the four preparation techniques.

METHODOLOGY:

A micro computed tomography scanner was used to analyse root canals in extracted maxillary molars. Specimens were scanned before and after canals were prepared using Ni-Ti – K-Files, Lightspeed instruments, ProFile.04 and GT rotary instruments. Differences in dentine volume removed, canal straightening, the proportion of unchanged area and canal transportation were calculated using specially developed software.

RESULTS:

Instrumentation of canals increased volume and surface area. Prepared canals were significantly more rounded, had greater diameters and were straighter than unprepared canals. However, all instrumentation techniques left 35% or more of the canals’ surface area unchanged. Whilst there were significant differences between the three canal types investigated, very few differences were found with respect to instrument types.

CONCLUSIONS:

Within the limitations of the micro CT system, there were few differences between the four canal instrumentation techniques used. By contrast, a strong impact of variations of canal anatomy was demonstrated. Further studies with 3D-techniques are required to fully understand the biomechanical aspects of root canal preparation.

By Peters OA, Schönenberger K, Laib A|2019-05-24T23:06:54+00:00January 1st, 2001|Other|

Mercury toxicity and systemic elimination agents

This paper reviews the published evidence supporting amalgam toxicity and clinical techniques that facilitate mercury elimination. A literature review is provided which documents effective mercury elimination strategies to improve mercury toxicity syndromes. Considering the weight of evidence supporting mercury toxicity, it would seem prudent to select alternative dental restoration materials and consider effective mercury elimination strategies if mercury toxicity is present.

By Mercola J, Klinghardt D.|2019-05-30T21:25:51+00:00January 1st, 2001|Mercury|

Recommendations for using fluoride to prevent and control dental caries in the United States.

Widespread use of fluoride has been a major factor in the decline in the prevalence and severity of dental caries (i.e., tooth decay) in the United States and other economically developed countries. When used appropriately, fluoride is both safe and effective in preventing and controlling dental caries. All U.S. residents are likely exposed to some degree to fluoride, which is available from multiple sources. Both health-care professionals and the public have sought guidance on selecting the best way to provide and receive fluoride. During the late 1990s, CDC convened a work group to develop recommendations for using fluoride to prevent and control dental caries in the United States. This report includes these recommendations, as well as a) critical analysis of the scientific evidence regarding the efficacy and effectiveness of fluoride modalities in preventing and controlling dental caries, b) ordinal grading of the quality of the evidence, and c) assessment of the strength of each recommendation. Because frequent exposure to small amounts of fluoride each day will best reduce the risk for dental caries in all age groups, the work group recommends that all persons drink water with an optimal fluoride concentration and brush their teeth twice daily with fluoride toothpaste. For persons at high risk for dental caries, additional fluoride measures might be needed. Measured use of fluoride modalities is particularly appropriate during the time of anterior tooth enamel development (i.e., age <6 years). The recommendations in this report guide dental and other health-care providers, public health officials, policy makers, and the public in the use of fluoride to achieve maximum protection against dental caries while using resources efficiently and reducing the likelihood of enamel fluorosis. The recommendations address public health and professional practice, self-care, consumer product industries and health agencies, and further research. Adoption of these recommendations could further reduce dental caries in the United States and save public and private resources.

By Kohn WG, Maas WR, Malvitz DM, Presson SM, Shaddik KK.|2018-07-24T20:30:05+00:00January 1st, 2001|Fluoride|

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About Han L, Edward C, Okatmoto A, Iwaku M.