The effect of calcitonin on osseous healing in guinea pig mandible

Detection and size differentiation of simulated tooth root defects using flat-panel volume computerized tomography (fpVCT)

OBJECTIVE

Our aim was to evaluate the capacity of flat-panel volume computerized tomography (fpVCT) to enable the observer to detect and differentiate 3 different sizes of simulated tooth root defects in radiographs.

STUDY DESIGN

Three simulated tooth root defects of different sizes and a defect-free area (160 sites in total) were randomly distributed on the buccal and lingual surface of 20 mandibular premolar roots of Sus scrofa domestica with round burs. For the imaging of the specimens, an fpVCT prototype was used. Findings were evaluated by 3 observers.

RESULTS

Cavity 0 (no lesion) was correctly identified in 53%, cavity 1 in 69%, cavity 2 in 96%, and cavity 3 in 89%. Altogether, the simulated cavities were classified in a correct manner in 77%. The values were compared using receiver operating characteristic curves. The area under the curve (AUC) for cavity 0 versus the pooled results for cavities 1-3 was found to be 0.72. The AUC for the pooled results for 0-2 (no pathologic impact) versus cavity 3 (potential pathologic impact) was 0.94. There was no significant dependence of the results on the observer (P = .37). Results with P < .05 were considered to be significant.

CONCLUSIONS

Flat-panel volume computerized tomography, which is currently used only as a research tool, has a high potential in detection and differentiation at an early stage of external root resorption cavities with pathologic relevance..

Effects of calcitonin on the biomechanics, histopathology, and radiography of callus formation in rats

BACKGROUND

This study was designed to examine the effect of salmon calcitonin on fracture repair.

METHODS

A transverse middiaphyseal fracture of the right tibia was surgically induced, and stabilized by an intramedullary Kirschner wire. Eighty male Wistar rats were arbitrarily assigned to four groups of 20 animals each. Groups I and II were the controls and did not receive any medication but did receive placebo injections. The other two groups received 5 IU/kg/day salmon calcitonin intramuscularly for 6 weeks (Group III) or for 10 weeks (Group IV) postoperatively. The formation and healing of the bones were determined by radiographic and histopathological analyses and by biomechanical tests.

RESULTS

In radiographic examinations, there were no statistically significant differences between groups I and III at week 6 or between groups II and IV at week 10. However, the histopathological evaluation scores were higher in the calcitonin group at the early stage (6 weeks) of fracture healing, which indicates a more mature callus formation (P < 0.05). The values for maximum torsional moment during fracture were higher in the calcitonin group in both stages of fracture healing (P < 0.01).

CONCLUSIONS

This study could have two important clinical implications. (1) Higher scores for the histopathological evaluation and a greater resistance to moment force applied at an early stage (week 6) of fracture healing imply that calcitonin intake might enable us to allow earlier mobilization and weight-bearing in clinical cases with rigid fixation. (2) At a late stage of fracture healing (week 10), the significantly better (P < 0.0001) results obtained in the biomechanical parameters used might imply that calcitonin intake could enable us to perform early implant removal, and strongly suggest that the strength and quality of the callus formation could be improved by administering calcitonin following a fracture.