Unit:
Department of DentistryΒιβλιοθήκη Οδοντιατρικής
Dissertation committee:
Τσολάκης Απόστολος, Αναπληρωτής Καθηγητής, Τμήμα Οδοντιατρικής, Σχολή
Επιστημών Υγείας, ΕΚΠΑ
Χαλαζωνίτης Δημήτριος, Καθηγητής, Τμήμα Οδοντιατρικής, Σχολή
Επιστημών Υγείας, ΕΚΠΑ
Περρέα Δέσποινα, Καθηγήτρια, Τμήμα Iατρικής, Σχολή
Επιστημών Υγείας, ΕΚΠΑ
Αγγελόπουλος Χρίστος, Καθηγητής, Τμήμα Οδοντιατρικής, Σχολή
Επιστημών Υγείας, ΕΚΠΑ
Γκιζάνη Σωτηρία, Αναπληρώτρια Καθηγήτρια, Τμήμα Οδοντιατρικής, Σχολή
Επιστημών Υγείας, ΕΚΠΑ
Τόσιος Κωνσταντίνος, Αναπληρωτής Καθηγητής, Τμήμα Οδοντιατρικής, Σχολή
Επιστημών Υγείας, ΕΚΠΑ
Βάρδας Εμμανουήλ, Επίκουρος Καθηγητής, Τμήμα Οδοντιατρικής, Σχολή
Επιστημών Υγείας, ΕΚΠΑ
Original Title:
Histological, radiographic and biochemical changes of the temporomandibular joint in rats following mandibular compressive loading
Translated title:
Histological, radiographic and biochemical changes of the temporomandibular joint in rats following mandibular compressive loading
Summary:
Objective
To investigate changes (radiographic, biochemical, histological) of the condyle and the mandible in rats that have undergone restriction in the mandibular growth through mechanical loading with an orthodontic / orthopedic device compared to rats without using the device.
Materials and Methods
Seventy-two Wistar rats were used in this study. They were divided into two equal groups of thirty-six rats each. Each group consisted of 3 subgroups. For each experimental subgroup there was a corresponding control subgroup, with no devices. The first day of the experiment was the 30th day of life of the experimental animals and the total duration of the experiment was 90 days. The animals were sacrificed after 30 (subgroups A1, B1), 60 (subgroups A2, B2) and 90 (subgroups A3, B3) days from the start of the experiment. On the 60th day of the experiment the orthodontic devices were removed from the remaining animals. During the whole experimental period, rats were fed mashed food. Cone beam computed tomographies were used for three-dimensional analysis. Blood samples were collected from the eye. Enzyme-linked immunosorbent assay (ELISA) kits were used to determine OPG, RANKL and MCSF levels in the blood serum. After sacrifice, the mandibular condyles were isolated and examined histologically.
Results
From the three-dimensional radiographic analysis, measurements revealed significant differences in the anteroposterior dimensions between experimental and control subgroups. However, the observed changes in the vertical dimensions, Condylion/Go’ - Menton and the Intercondylar distance proved insignificant. No statistically significant changes by group or timing were found in the levels of OPG, RANKL and MCSF. Histological analysis revealed significant histomorphometric differences in the mandibular condyle. In particular, the Bone Surface / Total Surface ratio was found diminished in both the anterior and posterior condylar regions. Lastly, a significant reduction was found in the Posterior Condylar Cartilage Thickness.
Conclusions
1. Posterior mandibular displacement of the mandible in growing rats affects the morphology of the mandible and culminates in the development of a smaller mandible at a grown age.
2. The orthodontic / orthopedic intervention was not shown to affecting the levels of the studied proteins in the systemic circulation.
3. Posterior mandibular displacement can cause histological region-specific changes in the microarchitecture of the condylar bone and cartilage thickness.
The present study emphasized the long-term stability of the outcomes, revealing that the mandible does not show catch-up growth following treatment.
Main subject category:
Health Sciences
Keywords:
Mandibular growth; Mandibular posterior displacement; Mandibular length; Condylar growth; Rat; Class III malocclusion; Orthodontic treatment, Osteoprotegerin, RANKL, MCSF, Condylar cartilage thickness
Number of references:
179
