IADR Abstract Archives

Cell Responses to Mechanical Loading in Human Cleidocranial Dysplasia

The cleidocranial dysplasia (CCD) is an autosomal dominant skeletal disorder characterized by an anomaly of the enchondral and intramembranous bone formation. Affected individuals may have hypo- or aplastic claviculae, brachycephaly, hypertelorism, supernumerary and ectopic teeth, dental root and crown abnormalities as well as a delayed tooth eruption. CCD is caused by mutations of the Runt-related transcription factor 2 (RUNX2) gene that plays a key role in osteoblast differentiation and osteoblast-specific gene expression. In addition, an important role of RUNX2 in the mechanoransduction process of osteoblasts was demonstrated.

Objective: An in-vitro study was established to analyse if and to what extent biomechanical loading regulates the RUNX2 gene expression in periodontal ligament (PDL) cells of patients with and without CCD.

Methods: PDL cells were obtained from supernumerary teeth of three CCD patients as well as from teeth of normal patients. The CCD patients were genotyped for several single nucleotide polymorphisms linked to the RUNX2 locus. PDL cells were grown by explants technique and subjected to static and dynamic strain of 3 and 20 % for up to 24 h. Subsequently, the RUNX2 gene expression was determined by real-time PCR. For statistical analysis, the Mann-Whitney U test was applied (p<0.05).

Results: The expression of RUNX2 mRNA was significantly affected by biomechanical forces in both CCD and normal patients. In normal patients, tensile strain of low magnitude stimulated significantly the RUNX2 gene expression, whereas tensile strain of high magnitude was mostly inhibitory. In CCD patients, the RUNX2 mRNA expression was significantly reduced irrespective of the magnitude at which the strain was applied.

Conclusion: Although clinical findings suggest that an orthodontic treatment can be performed successfully in CCD patients, our in-vitro results imply that the response of PDL cells to biomechanical loading is altered.

Acknowledgement: This study was supported by the German Research Foundation (KFO208/TP7).


Continental European, Israeli, Scandinavian Divisions Meeting
2009 Continental European, Israeli, Scandinavian Divisions Meeting (Munich, Germany)
Munich Germany
2009
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Scientific Groups
  • Rath-deschner, Birgit  ( Department of Orthodontics, University of Bonn, Bonn, N/A, Germany )
  • Deschner, James  ( Department of Periodontology, Operative and Preventive Dentistry, University of Bonn, Bonn, N/A, Germany )
  • Reichert, Christoph  ( Department of Orthodontics, University of Bonn, Bonn, N/A, Germany )
  • Wenghoefer, Matthias  ( Department of Oral and Maxillofacial Plastic Surgery, University of Bonn, Bonn, N/A, Germany )
  • Reimann, Susanne  ( Oral Technology, University of Bonn, Bonn, N/A, Germany )
  • Gotz, Werner  ( Department of Orthodontics, University of Bonn, Bonn, N/A, Germany )
  • Jager, Andreas  ( Department of Orthodontics, University of Bonn, Bonn, N/A, Germany )
    • Oral Session
    Prosthodontics & Craniofacial Development
    09/10/2009