Histological Alterations from Condyle Repositioning with Functional Appliances in Rats

Objective: This study was designed to assess the morphological and histological alterations of the condyle of rats undergoing forward mandibular repositioning via functional appliance.

Materials and Methods: Functional appliances were mounted onto the upper jaws of rats. Morphological analysis was conducted on micro-CT images of sacrificed animals. Histological changes in condyle were examined by immunohistochemistry using proliferating cell nuclear antigen (PCNA), matrix metalloproteases (MMPs), vascular endothelial growth factor (VEGF), tissue inhibitors of matrix metalloproteinases (TIMP-1), interleukin 1b (IL-1β), Aggrecan and Type II collagen. Osteoclast activity was identified by tartrate-resistant acid phosphatase (TRAP) staining.

Results: Morphological analysis confirmed the forward positioning of the condyles of rats by the appliance, but the position gradually returned to normal on days 14 after treatment. An increase in PCNA positive cells was observed in the posterior region of the condyles on days 7, whereas PCNA positive cells decreased in the anterior region. Aggrecan and Type II collagen localization increased in the posterior region throughout the entire period, but decreased in the anterior region on days 14. In both regions, IL-1β and VEGF localization was significantly increased for 14 days while MMPs localization was evident throughout the entire period. The TRAP positive cells were significantly elevated on days 3 and 7.

Conclusions: These results suggest that the functional appliance therapy induces significant morphological and histological changes in the anterior and posterior regions of the condyle and subsequently causes adaptive cellular functions such as chondrocyte differentiation and cartilage matrix formation.

functional appliance; mandibular condyle; histological analysis; cartilage

1. McNamara JA Jr. Components of class II malocclusion in children 8-10 years of age. Angle Orthod 51: 177-202, 1981.

2. Pancherz H, Ruf S, Kohlhas P. “Effective condylar growth” and chin position changes in Herbst treatment: a cephalometric roentgenographic long-term study. Am J Orthod Dentofacial Orthop 114: 437-446, 1998.

3. Ruf S, Pancherz H. The mechanism of Class II correction during Herbst therapy in relation to the vertical jaw base relationship: a cephalometric roentgenographic study. Angle Orthod 67: 271-276, 1997.

4. Peltola JS, Könönen M, Nyström M. A follow-up study of radiographic findings in the mandibular condyles of orthodontically treated patients and associations with TMD. J Dent Res 74: 1571-1576, 1995.

5. Peltola JS NM, Könönen M, Wolf J. Radiographic structural findings in the mandibular condyles of young individuals receiving orthodontic treatment. Acta Odontol Scand 53: 85-91, 1995.

6. Rabie AB, Shum L, Chayanupatkul A. VEGF and bone formation in the glenoid fossa during forward mandibular positioning. Am J Orthod Dentofacial Orthop 122: 202-209, 2002.

7. Sobue T, Yeh WC, Chhibber A, Utreja A, Diaz-Doran V, Adams D, Kalajzic Z, Chen J, Wadhwa S. Murine TMJ loading causes increased proliferation and chondrocyte maturation. J Dent Res, 90: 512-516, 2011.

8. Rabie AB, She TT, Hägg U. Functional appliance therapy accelerates and enhances condylar growth. Am J Orthod Dentofacial Orthop 123: 40-48, 2003.

9. Ruf S, Pancherz H. Temporomandibular joint remodeling in adolescents and young adults during Herbst treatment: A prospective longitudinal magnetic resonance imaging and cephalometric radiographic investiga-tion. Am J Orthod Dentofacial Orthop 115: 607-618, 1999.

10. Bendeus M, Hägg U, Rabie B. Growth and treatment changes in patients treated with a headgear-activator appliance. Am J Orthod Dentofacial Orthop 121: 376-384, 2002.

11. Kuroda S, Tanimoto K, Izawa T, Fujihara S, Koolstra JH, Tanaka E. Biomechanical and biochemical characteristics of the mandibular condylar cartilage. Osteoarthritis Cartilage 17: 1408-1415, 2009.

12. Wattanachai T, Yonemitsu I, Kaneko S, Soma K. Functional lateral shift of the mandible effects on the expression of ECM in rat temporomandib-ular cartilage. Angle Orthod 79: 652-659, 2009.

13. Kantomaa T, Pirttiniemi P. Changes in proteoglycan and collagen content in the mandibular condylar cartilage of the rabbit caused by an altered relationship between the condyle and glenoid fossa. Eur J Orthod 20: 435- 441, 1998.

14. Teramoto M, Kaneko S, Shibata S, Yanagishita M, Soma K. Effect of compressive forces on extracellular matrix in rat mandibular condylar cartilage. J Bone Miner Metab 21: 276-286, 2003.

15. Reynolds JJ. Collagenases and tissue inhibitors of metalloproteinases: a functional balance in tissue degradation. Oral Dis 2: 70-76, 1996.

16. Nagase H, Woessner JF Jr. Matrix metalloproteinases. J Biol Chem 274: 21491-21494, 1999.

17. Giannelli G, Erriquez R, Iannone F, Marinosci F, Lapadula G, Antonaci S. MMP-2, MMP-9, TIMP-1 and TIMP-2 levels in patients with rheumatoid arthritis and psoriatic arthritis. Clin Exp Rheumatol 22: 335-338, 2004.

18. Jackson C, Nguyen M, Arkell J, Sambrook P. Selective matrix metallo-proteinase (MMP) inhibition in rheumatoid arthritis-targetting gelatinase A activation. Inflamm Res 50: 183-186, 2001.

19. Von den Hoff JW, Delatte M. Interplay of mechanical loading and growth factors in the mandibular condyle. Arch Oral Biol 53: 709-715, 2008.

20. Pufe T, Harde V, Petersen W, Goldring MB, Tillmann B, Mentlein R. Vascular endothelial growth factor (VEGF) induces matrix metallopro-teinase expression in immortalized chondrocytes. J Pathol 202: 367-374, 2004.

21. Quinn R. Comparing rat’s to human’s age: how old is my rat in people years? Nutrition 21: 775–777, 2005.

22. Lee KY, Park JH, Tai K3, Chae JM. Treatment with Twin-block appliance followed by fixed appliance therapy in a growing Class II patient. Am J Orthod Dentofacial Orthop 150: 847-863, 2016.

23. Jung JK, Sohn WJ, Lee Y, Bae YC, Choi JK, Kim JY. Morphological and cellular examinations of experimentally induced malocclusion in mice mandibular condyle. Cell Tissue Res 355: 355-363, 2014.

24. Kubota E, Imamura H, Kubota T, Shibata T, Murakami K. Interleukin 1 beta and stromelysin (MMP3) activity of synovial fluid as possible markers of osteoarthritis in the temporomandibular joint. J Oral Maxil-lofac Surg 55: 20-27, 1997.