title: Experimental orthodontic tooth movement and extensive root resorption: periodontal and pulpal changes.
abstract: Previous studies have reported changes both in dental pulp and in periodontal ligament (PDL) following orthodontic tooth movement. However, pulpal changes following extensive root resorption after orthodontic tooth movement have not been studied in detail. The aim of this study was therefore to evaluate inflammatory changes, both in the dental pulp and in the compressed PDL, after experimentally induced extensive root resorption. Extensive root resorption was induced in rats by the activation and re-activation of orthodontic force, with a short intervening period of no force application. The distribution of immune cells, nerve fibres and blood vessels was studied immunohistochemically using antibodies against CD68-immunoreactive (IR) cells, major histocompatibility complex (MHC) class II Ia-expressing cells, CD43-IR cells, protein gene product 9.5 (PGP 9.5), and laminin. In the compressed PDL of experimental first molars, significantly increased density of CD68-IR cells and MHC class II Ia-expressing cells were found, whereas the density of CD43-IR cells were unchanged when compared with control second molars. In the compressed PDL, there was an increased density of blood vessels, but no sprouting of nerve fibres. In the dental pulp, however, no increased density of immune cells or sprouting of nerve fibres was recorded. In conclusion, inflammation after extensive root resorption was confined to the compressed PDL, whereas the dental pulp was unaffected.
authors.affiliation: Department of Clinical Dentistry, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway. polbhat.tripuwabhrut@iko.uib.no
authors.forename: Polbhat
authors.initials: P
authors.lastname: Tripuwabhrut
authors.forename: Pongsri
authors.initials: P
authors.lastname: Brudvik
authors.forename: Inge
authors.initials: I
authors.lastname: Fristad
authors.forename: Sivakami
authors.initials: S
authors.lastname: Rethnam
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D003782:Dental Pulp / Q000276:immunology / Q000473:pathology*; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D007797:Laminin / Q000032:analysis; D007963:Leukocytes, Mononuclear / Q000473:pathology; D051917:Leukosialin / Q000032:analysis; D008264:Macrophages / Q000473:pathology; D008297:Male; D055806:Microvessels / Q000473:pathology; D008963:Molar / Q000276:immunology / Q000473:pathology; D009412:Nerve Fibers / Q000473:pathology; D010513:Periodontal Ligament / Q000276:immunology / Q000473:pathology*; D010518:Periodontitis / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D011312:Pressure; D011671:Pulpitis / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012391:Root Resorption / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D013601:T-Lymphocytes / Q000473:pathology; D014087:Tooth Movement Techniques / Q000009:adverse effects*; D043222:Ubiquitin Thiolesterase / Q000032:analysis; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000949:Histocompatibility Antigens Class II; D007797:Laminin; D051917:Leukosialin; D043222:Ubiquitin Thiolesterase; C539355:CD68 protein, rat; D000097382:CD68 Molecule; C489034:UCHL1 protein, rat