title: Concomitant contact allergy to formaldehyde and methacrylic monomers in students of dental medicine and dental patients.
abstract: OBJECTIVE
  A multitude of acrylic monomers is used in dentistry. Formaldehyde is a ubiquitous chemical agent, which is an ingredient of some dental materials and may be released from methacrylate-based composites. The purpose of the study is to evaluate the incidence and the risk of cross-sensitization to some methacrylic monomers (methylmethacrylate - MMA, triethyleneglycol dimethacrylate - TEGDMA, ethyleneglycol dimethacrylate - EGDMA, 2,2-bis-[4-(2-hydroxy-3-methacrylo-xypropoxy)phenyl]-propane - Bis-GMA, 2-hydroxy-ethyl methacrylate 2-HEMA, and tetrahydrofurfuryl methacrylate) and formaldehyde in students of dentistry, dental professionals and dental patients.
  
  
  METHODS
  A total of 139 participants were included in the study, i.e., occupationally exposed dental professionals, students of the 3rd, 4th and 6th year of dental medicine, and occupationally unexposed dental patients. They were patch-tested with methacrylic monomers and formaldehyde. The results were subjected to statistical analysis (p < 0.05).
  
  
  RESULTS
  From the allergic to formaldehyde students of the 3rd and 4th year of dental medicine, 46.2% were also sensitized to MMA. Among the group of patients, the incidence of cross-sensitization to formaldehyde and methacrylic monomers was as follows: to TEGDMA - 20.6%, to ethyleneglycol dimethacrylate - 20.7%, to 2-HEMA - 20.7% and to tetrahydrofurfuryl methacrylate - 24.1%. Contact allergy to MMA was diagnosed among 22.7%, and to TEGDMA - among 27.1% of the students of the 3rd and 4th year of dental medicine. In the group of occupationally unexposed dental patients the prevalence of contact allergy to ethyleneglycol dimethacrylate was 20.7%, to Bis-GMA - 27.6%, to 2-HEMA - 44.9% and to tetrahydrofurfuryl methacrylate - 38.0%.
  
  
  CONCLUSIONS
  The students of the 3rd and 4th year of dental medicine could be outlined as a group at risk of sensitization to MMA and TEGDMA and of cross-sensitization to MMA and formaldehyde. Probably, due to the ubiquitous occurrence of formaldehyde and the wide use of composite resins and bonding agents containing TEGDMA, ethyleneglycol dimethacrylate, 2-HEMA and tetrahydrofurfuryl methacrylate in dentistry, the group of dental patients could be at risk of cross-sensitization to formaldehyde and some methacrylic monomers.
authors.affiliation: Medical Faculty, Department of Hygiene, Medical Ecology and Nutrition, Medical University, Sofia, Bulgaria, saly_grigory@abv.bg.
authors.forename: Maya
authors.initials: M
authors.lastname: Lyapina
authors.forename: Maria
authors.initials: M
authors.lastname: Dencheva
authors.forename: Assya
authors.initials: A
authors.lastname: Krasteva
authors.forename: Mariana
authors.initials: M
authors.lastname: Tzekova
authors.forename: Angelina
authors.initials: A
authors.lastname: Kisselova-Yaneva
mesh_terms: D000328:Adult; D002031:Bulgaria / Q000453:epidemiology; D003429:Cross Reactions; D003764:Dental Materials / Q000009:adverse effects*; D017449:Dermatitis, Allergic Contact / Q000453:epidemiology / Q000209:etiology*; D009783:Dermatitis, Occupational / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005557:Formaldehyde / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008689:Methacrylates / Q000009:adverse effects*; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D010361:Patients; D012307:Risk Factors; D013335:Students, Dental; D011795:Surveys and Questionnaires
chemical_list: D003764:Dental Materials; D008689:Methacrylates; D005557:Formaldehyde