Differential expression of neuropeptide Y Y1 receptors during pulpal inflammation.

AIM: To study the pattern of neuropeptide Y (NPY) Y1 receptor (Y1R) localization in the normal dental pulp and during different stages of pulpal inflammation. The hypothesis was that the expression of Y1R varies during different stages of pulpitis. METHODOLOGY: Pulp exposure injury was made on first molar teeth of Sprague-Dawley rats. Animals were killed 3, 7, 14, 21, 28 and 46 days after pulp exposure. Jaws were removed, decalcified and processed for immunohistochemistry for identification and localization of Y1R. Double labelling was performed using antibodies for laminin, CD43 and CD4 with Y1R. RT-PCR was performed to verify gene expression of Y1R in dental pulp and trigeminal ganglion. RESULTS: RT-PCR revealed the presence of NPY-Y1R in the dental pulp, trigeminal ganglion and gingiva. With immunohistochemistry, in control rats, Y1R was mainly located in capillaries and small vessels in the dental pulp as well as in the odontoblastic layer. No YIR was noted on immune cells in normal pulp. In pulpitis, immune cells such as CD43+ granulocytes and CD4+ lymphocytes expressed Y1R. As pulpitis progressed, there was a significant decrease in number of blood vessels expressing Y1R in the odontoblast layer when compared to control rat pulp. CONCLUSIONS: This study gives evidence that Y1R is a modulator of pulpal inflammation.

Hemostasis in endodontic microsurgery.

There are numerous ways to achieve hemostasis. With the abundance of hemostatic agents available and with the introduction of new products, one has to make an objective decision. A good agent achieves hemostasis within a short period of time, is easy to manipulate, is biocompatible, does not impair or retard healing, must be relatively inexpensive, is reliable, and works best for the particular surgical procedure. With these purposes in mind, the following sequence is recommended to achieve hemostasis during endodontic microsurgery. I. Presurgical: Give 2 to 3 Carpules of 1:50,000 epinephrine local anesthetic with multiple infiltration sites throughout the entire surgical field. II. Surgical: A. Remove all granulation tissue. B. Place an epinephrine pellet into the bony crypt followed by dry sterile cotton pellets. Apply pressure for 2 minutes. Remove all the cotton pellets except the first epinephrine pellet. Continue with the surgical procedure and remove the epinephrine pellet before final irrigation and closure. C. Alternatively, calcium sulfate can be mixed into a thick putty and packed against the bone cavity. Because it is a biodegradable material, calcium sulfate can be left in situ. In fact, in large bone defects and through-and-through lesions, additional calcium sulfate can be placed to fill the entire bone cavity as a barrier material. Healing is more predictable with little chance of scar tissue formation. Calcium sulfate resorbs in 2 to 4 weeks. D. Small bleeding sites in the bone can be brushed with ferric sulfate solution. III. Postsurgical: Tissue compression before and after suturing cuts down on postsurgical bleeding and swelling. Hemostasis is imperative in endodontic microsurgery for better visualization, a good environment for placement of retrograde filling material, and a more efficient surgical procedure with less blood loss.

Barrier membrane techniques in endodontic microsurgery.

The ultimate goal in endodontic microsurgery is the predictable regeneration of periapical tissues. One of the main concerns in treating an endodontically treated tooth which has a through-and-through osseous defect is that incomplete bone healing may be inevitable. This article reviews the use of different barrier membranes for bone regeneration. In addition, the indications, techniques, and prognosis of calcium sulfate in guided bone regeneration are presented.