Review of Related Lit. Local Tech Com

7/28/2019 Review of Related Lit. Local Tech Com

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CONCEPTUAL

LOCAL

Foreword:

Although clinician's skills and experience play a major role in designing and fabrication of theoptimum prosthodontic restorations, the selection of denture resins is equally important,especially when the patient has been using the prostheses since long.

IMPLEMENTING RULES AND REGULATIONS ON

(INDUSTRIAL HYGIENE) OF THE SANITATION is to considered among all practitioners.

he pursuit ofeconomic growth by the government through an accelerated

industrial development saw the emergence and proliferation of various

types and sizes of industries all over the country. This has tremendously

improved the economy and increased employment opportunities.

However, advances in technology in terms of the introduction of new chemicals,

processes, and techniques interlinked with development brought forth the inevitable

risks to life and limb resulting from increased exposure of workers to occupational

health hazards, injuries; and work-related illnesses.

In the light of this reality, the response of government is to assume. a proactive

stance to ensure that the fundamental task of safeguarding and promoting the

well-being of the Filipino workers is not compromised nor relegated to the

background.

In 1991, 15 years after the promulgation of PO 856, otherwise known as the

Sanitation Code of the Philippines, the Implementing Rules andRegulations (lRR)

for Chapter \,(11 - Industrial Hygiene of the Code was formulated to give full force

to the implementation of the provisions ofsaid chapter.

The onset of globalization brings to the fore the need to update and amend the

existing IRR ifwe are to respond to the challenges confronting our workers as they


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constantly adjust to the demands of the time and the changes taking place in their

work environment.

This amended version of the IRR is the collective effort of our partners from the various sectors

ofsociety, representing the different government agencies, NGOs, professional organizations, the academe, industry/management, and labor sector.

It is hoped that enforcement of this IRR will translate into concrete action our

aspiration to provide the nation's valuable human resources with a healthier and

safer work environment conducive to higher productivity and efficiency.

--ALBERTO G. ROMUALDEZ JR., M.D., M.P


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World Health Organization Geneva, 1998

The International Programme on Chemical Safety (IPCS),established in 1980, is a joint venture of the United NationsEnvironment Programme (UNEP), the International Labour Organisation(ILO), and the World Health Organization (WHO). The overallobjectives of the IPCS are to establish the scientific basis forassessment of the risk to human health and the environment fromexposure to chemicals, through international peer review processes, asa prerequisite for the promotion of chemical safety, and to providetechnical assistance in strengthening national capacities for thesound management of chemicals.

The Inter-Organization Programme for the Sound Management ofChemicals (IOMC) was established in 1995 by UNEP, ILO, the Food andAgriculture Organization of the United Nations, WHO, the UnitedNations Industrial Development Organization, and the Organisation forEconomic Co-operation and Development (Participating Organizations),following recommendations made by the 1992 UN Conference onEnvironment and Development to strengthen cooperation and increasecoordination in the field of chemical safety. The purpose of the IOMCis to promote coordination of the policies and activities pursued bythe Participating Organizations, jointly or separately, to achieve thesound management of chemicals in relation to human health and theenvironment.

WHO Library Cataloguing in Publication Data

Methyl methacrylate.

(Concise international chemical assessment document ; 4)

1.Methacrylates - toxicity 2.Environmental exposure3.Occupational exposure I.International Programme on ChemicalSafety II.Series

ISBN 92 4 153004 9 (NLM Classification: QV 50)ISSN 1020-6167

The World Health Organization welcomes requests for permission toreproduce or translate its publications, in part or in full.Applications and enquiries should be addressed to the Office ofPublications, World Health Organization, Geneva, Switzerland, whichwill be glad to provide the latest information on any changes made tothe text, plans for new editions, and reprints and translationsalready available.


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ENVIRONMENTAL FATE

A. Environmental Release

Methyl methacrylate is released to ambient air from productionfacilities, end-product manufacturers and storage (U.S. EPA1985). No atmospheric monitoring information was found formethyl methacrylate in the secondary sources searched;however, the chemical has been detected in the workplace undervarious conditions. In a polystyrene production plant,time-weighted-average (TWA) concentrations of 66 and 169 partsper billion (ppb) methyl methacrylate were detected in theworkers' breathing zones and the air of the workplace,respectively; maximum breathing zone and workplaceconcentrations were 378 and 3300 ppb, respectively. At fiveUS plants manufacturing polymethyl methacrylate, 8-hour TWAlevels of methyl methacrylate were measured at 16 to 360 mg/m3(3.9-87.84 ppm) (U.S. EPA 1985).

Of 204 heavily industrialized sites tested in the Chicago and

Illinois River basin area, only one surface water samplecontained methyl methacrylate (concentration of 10 ppb) (U.S.EPA 1985). Methyl methacrylate (10 ppb) has been detected inone of nine sites monitored in Lake Michigan, in a few USdrinking waters (


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methyl methacrylate may leach into groundwater (U.S. EPA

Methyl methacrylate;

toxicity;

dental appliances

Methyl methacrylate (MMA), a monomer of acrylic resin, has a wide variety of dental, medical and industrial

applications. Concerns have been raised regarding its potential toxicity in dental use, both for the patient and

also in the workplace. Dental patients are also exposed to MMA leached from some dental appliances and the

effects, at least in vitro , appear toxic to cells and may cause local mucosal irritation or even an allergic reaction.

When exposed to MMA in the dental clinic, dentists and other dental staff appear to occasionally suffer

hypersensitivity, asthmatic reactions, local neurological symptoms, irritant and local dermatological reactions.

The integrity of latex gloves may also be compromised after exposure to MMA during dental procedures. MMA

is not thought to be carcinogenic to humans under normal conditions of use. Techniques should be employed

to reduce patients' exposure to MMA during dental procedures in order to reduce the risks of possible

complications. Dental staff should avoid direct contact with MMA and room ventilation should be optimised.

---Leggat, P. A. and Kedjarune, U. (2003), Toxicity of methyl methacrylate in dentistry. International Dental

Journal, 53: 126 131. doi: 10.1111/j.1875-595X.2003.tb00736.x

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Associate Professor Ureporn Kedjarune, Head, Department of Oral Biology and Occlusion, Faculty of Dentistry,

Prince of Songkla University, Hat Yai, Songkhla 90112 Thailand.

Methyl methacrylate is primarily used as a chemical intermediate that is further processed topolymers. Main products are acrylic sheets, methacrylate esters, moulding, extrusion, emulsion anddispersion polymers as well as reactive resins. The substance is used in reactive resin preparationswhich are applied in industrial and skilled trade sectors such as in floor coatings, adhesives and dentalproducts. Methyl methacrylate may be a residual component in paints, lacquers and varnishes. Oralintake of small amounts of residual monomer migrating from food packaging materials may be a routefor consumer exposure. Consumers may be exposed to methyl methacrylate via variable amounts of residual monomer in a wide range of applications. From plastic products containing the methylmethacrylate-monomer migration of methyl methacrylate takes place.

GENERAL COMMENTS

The health part of the document is of excellent quality. The CSTEE agrees with the general conclusionthat there is a need for limiting the risks of methyl methacrylate concerning skin sensitisation and


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respiratory tract irritation at many workplaces in the chemical industry, industrial area and skilledtrade, and during use of casting resins. In addition, in several inhalation and combined inhalation anddermal exposure scenarios systemic toxicity gives rise to concern. The CSTEE does not agree withconclusion ii) for workers, as there is a need for further testing (inhalation sensitisation study androdent 2-generation reproduction study).

The environmental part of the Risk Assessment Report is written in a clear and concise form. Thedocuments follows the recommendations of the TGD, clarifying whether default or specific values havebeen used in the calculations. Calculations have been excluded from the RAR text but included asappendices. This solution produces a nice document, the rationale of which can be easily followed, andthe required transparency for decision-making kept. The conclusions are supported by the CSTEE.

---http://ec.europa.eu/health/scientific_committees/environmental_risks/opinions/sctee/sct_out90_en.htm


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