Signalling molecules in jaw bones and gingival tissues of patients with Class II and Class III dentofacial deformities.

OBJECTIVES: To detect signalling molecule specificities in jaw bone growth zones in skeletal class II and class III patients and compare them to those of a control group. MATERIAL AND METHODS: Twenty skeletal Class II and 20 skeletal Class III patients who underwent orthognathic surgery treatment were in the study group and five skeletal Class I patients who had impacted third molars extracted were in the control group. During the orthognathic surgery, tissue samples were taken from the tuber maxillae, ramus mandibulae anterior and posterior part together with mucosa from the gingival transitory fold in the second molar region of the lower jaw. The samples were stained to detect TGF-ß, BMP2/4, FGFR1, VEGF, OC, OP and MMP2 expression. The distributions of these factors were assessed semiquantitatively. RESULTS: We observed significant expression of TGF-ß, BMP2/4, OC and OP in the bone tissue of the study group. FGFR1 expression was more pronounced only in mucosa. VEGF and MMP2 were found only in some tissue samples. More apoptotic cells were observed in the bone tissue and soft tissue of the control patients than in those of the skeletal Class II and Class III patients, in which apoptotic cell frequencies were relatively equal. CONCLUSION: From bone tissue in tuber maxillae region the greater TGF-ß and BMP2/4 expression is seen in Class III and control groups, comparing to Class II. In ramus mandibulae anterior part the expression of significant factors in bone tissue growth (TGF-ß un BMP2/4) is higher in the control group and Class II patients, while in ramus mandibulae posterior part higher expression of TGF-ß and BMP2/4 is in Class III patients, comparing to Class II, which indicates to a preserved growth potential in these jaw bone regions. More active bone extracellular matrix protein (osteocalcin and osteopontin) expression in tuber maxillae region both in class II and class III patient groups and different expression in ramus mandibulae anterior part, prove to the bone mineralization and metabolism activity changes, which, perhaps, characterize just these dentofacial deformations.

Forward mandibular positioning enhances the expression of Ang-1 and Ang-2 in rabbit condylar chondrocytes.

Functional appliances correct dental malocclusion, partly by exerting an indirect mechanical stimulus on the condylar cartilage, initiating novel bone formation in the condyle. Angiopoietin is involved in the angiogenesis associated with novel bone formation. This study aimed to determine the expression of angiopoietin (Ang)­1 and ­2 following forward mandibular positioning (FMP) in the condylar chondrocytes of rabbits. Sixty rabbits (age, 8 weeks) were randomly allocated to the experimental and control groups (n=30 per group). In the experimental group, FMP was induced by a functional appliance. Five rabbits from the experimental group and the control group were sacrificed following 3 days and 1, 2, 4, 8 and 12 weeks, respectively. The right temporomandibular joints (TMJs) were collected and the expression of Ang­1 and -2 was evaluated by immunohistochemical staining. The expression of Ang-1 increased at day 3 and reached a peak at 2 weeks, whereas Ang­2 reached maximal expression 4 weeks after FMP. Subsequently, the expression of Ang­1 and ­2 gradually decreased. Thus, FMP enhanced the expression of Ang­1 and Ang­2 in condylar cartilage, which is related to angiogenesis in the process of endochondral ossification.