Effects of clodronate on early alveolar bone remodeling and root resorption related to orthodontic forces: a histomorphometric analysis.
BACKGROUND
The objective of this study was to evaluate the short-term effects of clodronate, a first-generation bisphosphonate, on early alveolar bone remodeling and root resorption related to orthodontic tooth movement.


METHODS
The samples consisted of 54 sex-matched Wistar rats (weight, 180-230 g) allocated to the 2.5 mmol/L clodronate, 10 mmol/L clodronate, and control groups (n = 18 for each group). After application of a nickel-titanium closed-coil spring (force, 60 g) between the maxillary central incisor and first molar, 2.5 mmol/L of clodronate, 10 mmol/L of clodronate, or saline solution was injected into the subperiosteum adjacent to the maxillary first molar every third day. All animals received tetracycline, calcein, and alizarin red by intraperitoneal injection at 1, 6, and 14 days, respectively. The amounts of tooth movement were measured at 3, 6, 9, 12, and 15 days. The animals were killed at 4, 7, and 17 days. Histomorphometric analyses of bone mineral appositional rate, labeled surface, percentage of root resorption area, and number of root resorption lacunae of the mesiobuccal root of the maxillary first molar at 4, 7, and 17 days were done. One-way analysis of variance (ANOVA) with the post-hoc test were done for statistical analyses.


RESULTS
Rats in the 10 mmol/L clodronate group had significant decreases of tooth movement (12 and 15 days, P <0.05) and percentages of root resorption area and numbers of root resorption lacunae (7 day, P <0.05), and increases of labeled surface and mineral appositional rates (17 day, P <0.05) over those of the 2.5 mmol/L clodronate and control groups.


CONCLUSIONS
Although clodronate might decrease root resorption related to orthodontic tooth movement, patients should be informed about a possible decrease in the amount of tooth movement and a prolonged period of orthodontic treatment.
Department of Orthodontics, School of Dentistry, Seoul National University, Seoul, Korea.
Josefina
J
Choi
Seung-Hak
SH
Baek
Jae-Il
JI
Lee
Young-Il
YI
Chang
D000539:Alveolar Process / Q000187:drug effects* / Q000473:pathology; D000818:Animals; D000880:Anthraquinones; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000494:pharmacology*; D016723:Bone Remodeling / Q000187:drug effects*; D002113:Calcification, Physiologic / Q000187:drug effects; D004002:Clodronic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D003722:Dental Alloys / Q000737:chemistry; D005260:Female; D005452:Fluoresceins; D005456:Fluorescent Dyes; D007180:Incisor / Q000187:drug effects / Q000473:pathology; D008297:Male; D008963:Molar / Q000187:drug effects / Q000473:pathology; D009532:Nickel / Q000737:chemistry; D009969:Orthodontic Wires; D051381:Rats; D017208:Rats, Wistar; D012391:Root Resorption / Q000473:pathology / Q000517:prevention & control*; D013314:Stress, Mechanical; D013752:Tetracycline; D013997:Time Factors; D014025:Titanium / Q000737:chemistry; D014087:Tooth Movement Techniques / Q000295:instrumentation / Q000379:methods*
D000880:Anthraquinones; D050071:Bone Density Conservation Agents; D003722:Dental Alloys; D005452:Fluoresceins; D005456:Fluorescent Dyes; D004002:Clodronic Acid; C040654:titanium nickelide; C010078:alizarin; D009532:Nickel; D014025:Titanium; D013752:Tetracycline; C007740:fluorexon