ABSTRACT
Nitric oxide [NO] produced by NO synthase [N O S] is considered a factor for vascular and immune system control, and it is increased according to mechanical stimuli. This study was aimed to examine the expression of Nitric oxide synthase in the periodontal ligament and alveolar bone surrounding the nonfunctional and hyperfunctional teeth. Twenty five rabbits used in this study were classified as five rabbits for teeth in normal occlusion, ten rabbits with nonfunctional right lower first molar by grinding the opposing teeth and ten rabbits with right lower first molar in trauma from occlusion by bonding 0.5 mm3 of light - cured composite. After two weeks all animals were sacrificed, the specimens were taken and prepared for immunohistochemical staining of N O S. the quantitative evaluations of the immune reactions were performed by digital image analysis. The result of this study had revealed that the N O S more detectable in the blood vessels, periodontal ligament and bone cells surrounding teeth subjected to trauma from occlusion followed by teeth in normal occlusion but less detectable surrounding nonfunctional teeth. So we conclude that Nitrous Oxide mediator which synthesized from L-arginine in process catalyzed by nitric oxide synthase may play an important regulatory role blood vessels expansion and as mediator of mechanical stress maintaining the integrity of periodontal tissue under physiological conditions
ABSTRACT
Purpose: An animal study was earned out to evaluate the effect of locally implanted polylactic polyglycolic acid [Fisiograft] on bone repair in induced bone defects
Materials and Method: Eighteen, 2-3 months old, male guinea pigs weighing between 200 and 250 grams were used in this study. After anesthesia, each animal was subjected to implantation of Fisiograft in an induced bony cavity at the right side of the submental region. A similar bony cavity was induced on the left side to serve as a control. Animals were divided into 3 groups, each of 6. They were sacrificed at 2, 6 and 12 weeks following implantation. The mandibles were dissected out, fixed, decalcified and stained using both hematoxylin and eosin and Massqn's trichrome stains
Results: There was no evidence of adverse responses in any of the animals throughout the study. At 2 and 6 weeks, histological examination revealed that gradual new bone formation took place at the experimental sides in a more rapid rate than that occurred at the control sides. At 12 weeks, the level of reossirlcation had adjusted similarly in both study and control sides
Conclusion: Fisiograft is allowing fibro-vascular tissue ingrowth, permitting bone healing in a more rapid rate, completely reabsorbed, and do not cause foreign body reactions. These advantages make it a promising choice when the jaw bone augmentation is needed
ABSTRACT
To avoid the hepatic first pass drugs effects, different absorption enhancers were used to achieve the optimal drug delivery via the buccal mucosa. Twenty male rabbits were used in this study weighing from 400-500 gm. These animals were divided into four groups; the 1[st] one [comprised 2 animals] was considered as a control group, while the 2[nd], 3[rd] and the 4[th] [6 animals each] were considered as experimental groups. A patch material was adhered to the buccal mucosa opposite to the upper first molar of the control group. Also the patch materials soaked with sodium glycodeoxycholate [GDC] solution 1%, 2% and 3% were adhered to the buccal mucosa in the same site of the 2[nd] 3[rd] and 4[th] experimental groups respectively, one hour daily for three weeks. The specimens were taken from the buccal mucosa after sacrification of the animals to be prepared for ultra- structural examination by transmission electron microscope. The results had revealed that the application of 1% of GDC was the safest concentration than 2% and 3% which was the most toxic one as revealed by the presence of deleterious and dramatic harmful ultrastructural changes in desmosmal, hemidesmosomal attachments and in the mitochondriae. These harmful changes had comprised the loss of desmosmal, hemidesmosomal attachments and lysis of mitochondrial matrix and its cristae with the presence of electron dense drug material inside the mitochondriae and in the connective tissue around blood capillaries associated with collagen fibers degeneration. In contradictory, the 1% GDC concentration had passed intercellulary without these pervious harmful intracellular changes indicating that the pathway of GDC 1% concentration is passing through the buccal mucosa intercellulary without intracellular leakage of its drug material. Thus we can concluded that the absorption enhancement is no longer the main problem but instead of that; the safety of the enhancers, the route of administration and the concentration effect relationship of the enhancer are important issues to achieve optimal drug absorption enhancement. So GDC at 1% concentration may improve delivery of various chronic administration of drugs into systemic circulation through buccal mucosa