title: Root resorption related to hypofunctional periodontium in experimental tooth movement.
abstract: Orthodontic movement of non-occluding teeth may result in undesirable apical root resorption. These teeth present with a histologically altered periodontium and are considered to be hypofunctional. The purpose of this study was to compare the amount of root resorption associated with a normal and a hypofunctional periodontium in rats during experimental tooth movement caused by heavy continuous force. The mandibular first molar was induced into a non-occluding condition in the hypofunctional periodontium group. Mesial orthodontic force was applied by means of 50-gram-force closed-coil springs for 15 days in both groups. The active root-resorption lacunae from histological sections, identified by tartrate-resistant acid phosphatase, were measured in terms of length, depth, and area. The results showed that the amount of root resorption was significantly greater in teeth with a hypofunctional periodontium than in those with a normal periodontium (p < 0.05). These results suggest that orthodontic movement of non-occluding teeth should be performed with caution.
authors.affiliation: Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Science, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Sringkarnboriboon
authors.forename: Y
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: K
authors.initials: K
authors.lastname: Soma
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D007527:Isoenzymes / Q000032:analysis; D008297:Male; D008310:Malocclusion / Q000503:physiopathology / Q000628:therapy; D008963:Molar / Q000473:pathology; D009969:Orthodontic Wires; D010519:Periodontium / Q000473:pathology / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012391:Root Resorption / Q000209:etiology* / Q000473:pathology; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D000071681:Tartrate-Resistant Acid Phosphatase; D014087:Tooth Movement Techniques / Q000295:instrumentation; D016474:Weight-Bearing / Q000502:physiology
chemical_list: D015415:Biomarkers; D007527:Isoenzymes; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase