title: Impact of nocturnal bruxism on mercury uptake from dental amalgams.
abstract: The mercury (Hg) release from dental amalgam fillings increases by mechanical stimulation. The aim of this study was to investigate the possible impact of nocturnal bruxism on Hg exposure from dental amalgams and to evaluate the effect of an occlusal appliance. 88 female patients from an orofacial pain clinic with a complete maxillary and mandibular dentition, a normal frontal vertical overbite with cuspid guidance, and at least 4 occlusal amalgam fillings in contact with antagonists in intercuspidal position, were examined with the Bruxcore bruxism monitoring device to measure the level of on-going nocturnal bruxism. Based on the degree of abrasion recorded, the subjects were divided into a group defined as bruxists, (n = 29), another group defined as non-bruxists, (n = 32), serving as controls, the intermediate group being discarded. The Hg exposure was assessed from the Hg concentration in plasma and urine, corrected for the creatinine content. In a regression model with bruxism as the only explanatory variable, no significant effect of bruxism was found, but when the number of amalgam fillings, chewing gum use, and other background variables were taken into account, there was a limited impact of bruxism on Hg in plasma. The nocturnal use of an occlusal appliance did not, however, significantly change the Hg levels. This study indicates that mechanical wear on amalgams from nocturnal bruxism may increase the Hg uptake, but the magnitude of this effect seems to be less than from the use of chewing gum.
authors.affiliation: Orofacial Pain Clinic, Postgraduate Dental Education Centre, Orebro County Council, Sweden. goran.isacsson@pain.se.astra.com
authors.forename: G
authors.initials: G
authors.lastname: Isacsson
authors.forename: L
authors.initials: L
authors.lastname: Barregård
authors.forename: A
authors.initials: A
authors.lastname: Seldén
authors.forename: L
authors.initials: L
authors.lastname: Bodin
mesh_terms: D000042:Absorption; D000293:Adolescent; D000328:Adult; D002012:Bruxism / Q000503:physiopathology* / Q000517:prevention & control; D002638:Chewing Gum; D003404:Creatinine / Q000097:blood / Q000652:urine; D003723:Dental Amalgam / Q000737:chemistry*; D019554:Dental Restoration Wear; D003793:Dental Restoration, Permanent; D004781:Environmental Exposure; D005069:Evaluation Studies as Topic; D005157:Facial Pain / Q000503:physiopathology / Q000517:prevention & control; D005260:Female; D006801:Humans; D008628:Mercury / Q000097:blood / Q000737:chemistry* / Q000493:pharmacokinetics / Q000652:urine; D008875:Middle Aged; D017090:Occlusal Splints; D012044:Regression Analysis; D013314:Stress, Mechanical; D013499:Surface Properties; D011795:Surveys and Questionnaires
chemical_list: D002638:Chewing Gum; D003723:Dental Amalgam; D003404:Creatinine; D008628:Mercury