title: Evaluation of oral tissue response and blood levels of mercury released from dental amalgam in rats.
abstract: Dental amalgam is the most common restorative material used in dentistry. It was reported that amalgam might constitute potential toxic hazards to pregnant patients and foetuses through mercury release and absorption. The present study aimed to investigate the vital tissue response in contact to dental amalgam plus determination of blood mercury levels in mother and offspring Wistar strain albino rats. Pregnant mothers were divided into two main groups each had dental amalgam implanted into either an oral mucosa incision or a bony socket following extraction. Third and fourth groups included the offspring rats of mothers from the first and second groups, respectively. The blood mercury levels and histopathology of oral tissues were analyzed in mothers at one and six months post-implantation and in offspring rats one day after birth. The blood mercury levels of mothers increased significantly at six months (P<0.01) as compared to levels at one month. However, blood mercury levels were not significant (P>0.05) when the two offspring (third and fourth) groups were compared. Histopathology results from mothers showed inflammatory response at the bottom of the socket, one month after amalgam implantation. At six months, teeth germs showed vacuolation of the abnormal odontoblasts with globular dentine formation. Degenerated periodontal fibres and thin trabeculae forming the bony sockets with large marrow spaces were evident. A fibrous connective tissue capsule surrounded the amalgam mass inside the mucosa of mothers at one month and was evident also at 6 months with a huge inflammatory cell infiltrate. Teeth germs showed elongated odontoblasts with intercellular oedema, thinner dentine and bony trabeculae with wider marrow spaces. Offspring rats showed comparable oral tissue response.
  
  
  CONCLUSIONS
  There is a positive correlation between blood mercury levels and oral tissue response in mothers, however, the negative impact of mercury on oral tissues of offspring rats was due to high mercury levels in their mothers' blood during pregnancy. We would recommend that women should - as far as possible - postpone having dental amalgam filling placed or removed during pregnancy to avoid its harmful effect on the foetus. Further clinical studies are recommended to test our findings in man.
authors.affiliation: Department of Oral Biology, College of Dentistry, University of Dammam, Dammam, Saudi Arabia.
authors.forename: Essam
authors.initials: E
authors.lastname: Soussa
authors.forename: Yosreya
authors.initials: Y
authors.lastname: Shalaby
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Maria
authors.forename: Ola M
authors.initials: OM
authors.lastname: Maria
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001853:Bone Marrow / Q000187:drug effects / Q000473:pathology; D003238:Connective Tissue / Q000187:drug effects / Q000473:pathology; D003723:Dental Amalgam / Q000737:chemistry*; D003804:Dentin / Q000187:drug effects / Q000473:pathology; D003810:Dentinogenesis / Q000187:drug effects; D005260:Female; D008628:Mercury / Q000009:adverse effects* / Q000097:blood / Q000737:chemistry; D009061:Mouth Mucosa / Q000187:drug effects* / Q000473:pathology; D009804:Odontoblasts / Q000187:drug effects / Q000473:pathology; D010513:Periodontal Ligament / Q000187:drug effects / Q000473:pathology; D011247:Pregnancy / Q000097:blood; D011297:Prenatal Exposure Delayed Effects; D051381:Rats; D017208:Rats, Wistar; D013280:Stomatitis / Q000139:chemically induced; D013997:Time Factors; D014059:Tongue / Q000187:drug effects; D014083:Tooth Germ / Q000187:drug effects* / Q000473:pathology; D020390:Tooth Socket / Q000187:drug effects* / Q000473:pathology
chemical_list: D003723:Dental Amalgam; D008628:Mercury