ABSTRACT
Objective: pulp regeneration within the root canal of necrotic teeth is considered an ideal treatment to allow for continued root development and recover teeth vitality. This study aims to evaluate the inductive effect of platelet-rich plasma [PRP] on expression of angiogenesis factors and pulpal revascularization of immature necrotic teeth
Materials and Methods: in this experimental animal study, we randomly divided 28 immature premolars from two mixed breed dogs into four groups, two experimental, negative and a positive control. Premolars in negative control group were left intact to develop normally. In the positive control and experimental groups, we removed the pulps and induced pulp necrosis, after which the chambers were sealed. Then, we applied the revascularization protocol in the experimental teeth located in the right quadrant. Two months later, the same protocol was applied to the left quadrant. The root canals were disinfected by irrigation with sodium hypochlorite [NaOCl] solution and application a triple antibiotic past. Following the induction of a blood clot [BC] inside the canal space, the coronal portion of the canals was assigned to either of two experimental groups: group 1 [BC+PRP+ mineral trioxide aggregate [MTA]], group 2 [BC+MTA]. Access cavities were sealed with a Glass Ionomer. The jaws that held the teeth were processed for histologic analysis of newly formed tissue and immunohistochemical evaluation according to vascular endothelial growth factor [VEGF] and factor VIII expressions in the canals
Results: histological analysis demonstrated no significant difference in the formation of new vital tissue inside the root canals between groups1 [42.8%] and 2 [43.5%, P>0.05]. Based on immunohistochemical evaluation, micro-vessel density [MVD] of the granulation tissues in both groups were similar and were higher compared with the normal pulp. We observed strongly positive expressions of VEGF and factor VIII in the stromal and endothelial cells, with severe intensity after one month. Both factors showed down-regulation at three months postoperative
Conclusion: PRP could not increase the formation of new vital tissue. The immunohistochemical results showed that VEGF and factor VIII played a pivotal role in the formation of new vessels inside the root canals of immature, non-vital teeth
ABSTRACT
The purpose of this study was to evaluate vertical facial and dental changes after orthodontic treatment with extraction of first four premolars, and to find whether long facial height could influence the treatment result. Fifty-six orthodontic patients with the minimum age of 15, whose treatment plan involved extracting four first premolars, participated in the study. The patients included 30 females and 27 males. Cephalometric measurements before and after treatment were compared using a paired T-test. Independent T-test was employed to compare post treatment changes for each parameter between normal and long face groups. The same analysis performed between male and female subjectsTreatment changes revealed a significant increase in the vertical distance from the upper molar to palatal plane, the lower molar to mandibular plane and Menton to palatal plane in all groups. There was significantly more increase in most post-treatment linear measurements in males than in females, with the same direction in both genders. There were no significant differences between normal and long face in any measurement. All patients showed some extrusion of the molar teeth after extraction of the premolars. The difference between normal and long face groups was not significant