Dental technician

Handlers of methyl methacrylate cement have developed paresthesia of the fingers. Dental technicians who use bare hands to mold methyl methacrylate putty had significantly slower distal sensory conduction velocities from the digits, implicating mild axonal degeneration in the area of contact with methyl methacrylate. The toxic effect on the nervous tissues may be due to diffusion into the nerve cells causing lysis of the membrane lipids and destruction of the myelin sheath. 

Seppalainen A, Rajaniemi R Local neurotoxicity of methyl methacrylate among dental technicians. Am J Ind Med 5 471-477, 1984. 

L A dental technician begins to display symptoms, including tremors, depression, and insomnia. Which of the following chemicals present in the workplace may be responsible for the symptoms ... 

C. The symptoms are characteristic of a person chronically exposed to vapors released from elemental mercury. Since the dental technician may handle elemental mercury, including mishandling, the symptoms presented may occur. While the technician may be exposed to solvent vapors released from dental adhesives, the symptoms are not characteristic of this type of exposure. Fluoride toxicity would not be expected because these are not symptoms associated with fluoride ingestion, and the patient and not the technician would be most likely exposed to quantities high enough to cause any symptoms. The technician has little exposure to li-docaine, and the symptoms are not typical of lido-caine toxicity. 

Selden Al, Persson B, Bornberger-Dankvardt SI, et al. 1995. Exposure to cobalt chromium dust and lung disorders in dental technicians. Thorax 50 769-772. 

Donaghy M, Rushworth G, Jacobs JM. Generalized peripheral neuropathy in a dental technician exposed to methyl methacrylate monomer. Neurology 1991 41(7) 1112-16. 

Dental technicians are potentially exposed to various occupational dusts and chemicals and pulmonary granulomatosis has been reported (15). 

Dental technicians Soaps and detergents, soldering fluxes, adhesives, acrylics, solvents, mercury... 

Cartridge makers Cement workers Ceramics makers Chemical equipment workers Construction workers Cutlery makers Demolition workers Dental technicians Diamond polishers Dye makers... 

Be unfortunately, this is still contained in some dental alloys because the mechanical qualities are improved by its presence. Indeed, beryllium is highly allergenic and toxic, and several cases of lung berylliosis have been reported in dental technicians working with alloys containing Be (Lob and Hugonnaud 1977 Choudat 1982 Choudat etal. 

Example 22-1 A dental technician takes X-rays of patients teeth. The control cord for the X-ray machine allows the technician to stand 3 ft away. If the control cord were longer and allowed the technician to stand 9 ft away, what reduction in radiation level would result ... 

Hairdresser Baker Electroplaters Florfet Confectioner Tile setters Plumber Metal. Surfiaoeworker Dental technician Cooks Health service Mechanician Leather worker... 

Hairdressers Bakers Electropfaters Florists Confectioners Tiiers Plumbers Metalworkers, welders Dental Technicians Cooks... 

Workers handling raw material, in particular sand and kaolin the latter also regularly contains considerable quantities of silica Dental technicians... 

Choudat D (1994) Occupational lung diseases among dental technicians. Tuber Lung Dis 75 99-104 Christy WC, Rodnan GP (1984) Conjuged progressive systemic sclerosis (scleroderma) report of the disease in husband and wife. Arthritis Rheum 27 1180-1182 Conrad K, Mehlhorn J, Liithke K, Dorner T, Frank KH (1996) Systemic lupus erythematosus after heavy exposure to quartz dust in uranium mines clinical and serological characteristics. Lupus 5 62-69... 

The following chapter describes different aspects of occupational contact dermatitis of dental personnel. In particular, occupational skin problems of dentists, dental assistants, dental technicians and orthodontists will be discussed. 

In a German study, 24% of the dental technicians with suspected occupational skin disease who were investigated were found to suffer from ICD (Rustemeyer and Frosch 1996). Major factors contributing to the development of ICD were found to be wet work with plaster, grinding and physical irritation, as caused by polishing of metal and plastic materials (Estlander et al. 1984 Rustemeyer and Frosch 1996). 

In recent studies among dental technicians, slight forms of ICD were observed frequently (Peiler, Rustemeyer and Frosch, unpublished data). In general, these skin affections were accepted to be normal among employees and did not result in consultation with a dermatologist. Since in ICD the barrier function of the epidermis is damaged, contact allergens can easily penetrate into the skin and, thus, result in increased risk of contact sensitization (Nishijima et al. 1997). In Table 3, common contact irritants for dental personnel are summarized. 

Table 6. Pattern of concomitant positive patch-test reactions to the major methacrylates, as evaluated in 35 dental technicians with occupational allergic contact dermatitis (adapted from Rustemeyer and Frosch 1996)...

Cleenewerck MB (1997) Current features of allergic occupational dermatoses. Rev Fr Allergol Immunol Clin 37 617-633 Estlander T, Rajaniemi R, Jolanki R (1984) Hand dermatitis in dental technicians. Contact Dermatitis 10 201-205 Estlander T, Kanerva L, Kari O, Jolanki R, Molsa K (1996) Occupational conjunctivitis associated with type IV allergy to methacrylates. Allergy 51 56-59... 

Hydroquinone is mainly used in photography, in black and white, X-ray, and microfilm developers. Sensitization can be found in dental technicians too. 

Melamine-formaldehyde resin (MFR) is an active ingredient of strong (reinforced) plasters. Sensitization was reported in a plaster-room technician, who applied resin-reinforced plaster casts, and in dental technicians. MFR was contained in a strong dental plaster used for mouldings. Used as a textile finish resin, it was also found to be an allergen in a women who replaced clothes in a store. MFR also releases formaldehyde, which may be the sensitizer. 

Pentaerythritol triacrylate is a multifunctional acrylic monomer. It can be found in photopolymerizable printer s ink. Sensitization was decribed in dental technicians and in a textile fabric printer. 

Methacrylates are used in the production of a great variety of polymers. As they are moderate to strong sensitizers, sensitization occurs in many professions. Dental technicians, assistants, and surgeons are frequently exposed. Methacrylates were reported as occupational allergens in chemically cured sculptured nails. 

Sensitization to 1,4-butanediol dimethacrylate (BUD-MA) was reported in dental technicians, with cross reactivity to methylmethacrylate. 

The crosslinking agent of acrylic resins, ethyleneglycol dimethacrylate (EGDMA), is employed to optimize the dilution of high-viscosity monomers and to link together the macromolecules costituting the polymer. It caused contact dermatitis in dental technicians and dental assistants. A case was also reported in a car rear-view mirror manufacturer. 

Farli M, Gasperini M, Francalanci S, Gola M, Sertoli A (1990) Occupational contact dermatitis in 2 dental technicians. Contact Dermatitis 22 282-287 Kanerva L, Jolanki R, Estlander T (1995) Occupational allergic contact dermatitis from 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate in a modified acrylic structural adhesive. Contact Dermatitis 35 84-89... 

Sensitization to 2-hydroxyethyl methacrylate mainly concerns dental technicians and dentists, but can also occur in other workers, such as printers. 

---