Complete physical mapping of IL6 reveals a new marker associated with chronic periodontitis.

BACKGROUND AND OBJECTIVE: Interleukin-6 (IL-6) is a powerful stimulator of osteoclast differentiation and bone resorption. Production of IL-6 is modulated by polymorphisms, and higher levels of this cytokine are found locally in patients with chronic periodontitis. In this study we performed a modern approach - Complete physical mapping of the IL6 gene - to identify the polymorphisms associated with chronic periodontitis in a southern Brazilian population sample. MATERIAL AND METHODS: One-hundred and nine individuals of both genders (mean age: 41.5 ± 8.5 years) were divided into a study group (56 participants with periodontitis) and a control group (53 individuals without periodontitis). After collection and purification of DNA, nine tag single nucleotide polymorphisms (SNPs; rs1524107, rs2069835, rs2069837, rs2069838, rs2069840, rs2069842, rs2069843, rs2069845 and rs2069849) covering the entire gene were selected according to the information available on the International HapMap Project website and evaluated using real-time PCR. RESULTS: Differences in the distribution of the following parameters were statistically significant between study and control groups: number of teeth (p = 0.030); probing depth (p < 0.001); clinical attachment level (p < 0.001); gingival index (p < 0.001); plaque index (p = 0.003); calculus index (p < 0.001); and dental mobility (p < 0.001). It was found that marker rs2069837 (located in intron 2 of IL6) under G dominant was associated with protection against chronic periodontitis in a Brazilian population in the presence of clinical variables, such as visible plaque, dentist visit frequency and dental floss use, and was suggested for the first time as a marker of susceptibility to chronic periodontitis. CONCLUSION: Complete physical mapping of IL6 (using tag SNPs) was carried out for the first time, unveiling allele G of polymorphism rs2069837 (located in the second intron of IL6) as a suggestive marker of protection against chronic periodontitis in a Brazilian population.

Histological and immunohistochemical evaluation of biphasic calcium phosphate and a mineral trioxide aggregate for bone healing in rat calvaria.

This work focused on the process of bone repair of defects in standardized calvaria of Wistar rats treated with biphasic calcium phosphate (BCP), mineral trioxide aggregate (MTA), or a combination of the two. Eighty Wistar rats were divided into four treatment groups and were examined at 2 and 8 weeks. A surgical defect was created in the calvaria using a 6-mm diameter trephine drill. The cavity was treated with BCP, MTA, or BCP+MTA; untreated rats with clot formation served as controls. Samples were evaluated histologically and by immunohistochemical staining for areas of new osteoid tissue and new bone tissue, as well as the percentage of labelled cells using anti-bone morphogenetic protein receptor type 1B (anti-BMPR1B) antibodies. Statistically significant differences were found for all dependent variables (area of new osteoid tissue, area of new bone, and percentage immunostaining) by group (P<0.0001) and time (P<0.0001), and for the interaction of the two (P<0.0001). The MTA group at 8 weeks showed the highest amount of osteoid tissue. The same group also exhibited the highest amount of bone tissue formation. The 2-week MTA samples and 2-week BCP+MTA samples exhibited the highest percentages of stained cells. The best results in terms of the area of osteoid and bone tissue formation and the percentage of BMPR1B were observed for the MTA group, confirming that the combination of BCP+MTA does not result in a significant improvement.

Bismuth subgallate as a topical haemostatic agent at the palatal wounds: a histologic study in dogs.

This study evaluated the early recovery process of the palatal wounds of dogs using bismuth subgallate. Five healthy adult male dogs underwent eight 5-mm partial-thickness punch biopsies in two paired columns on the palatal mastigatory mucosa. For the haemostasis, one side received moistened gauze pressure (test group 1), and the other received bismuth subgallate (test group 2). A description of the epithelium and connective tissue repair was made at 3, 7, 14 and 21 days. During the first days, a mass of disorganized tissue covered the connective tissue, in which there was intense chronic inflammation, and migration of epithelium cells from the edges towards the central region to close to the wound was seen. The final evaluation demonstrated well organized epithelial and connective tissues in all the samples. Epithelium thickness was measured at 0, 14 and 21 days, from images of the digitalized histological sections. In comparisons between the test groups, the bismuth subgallate group was slightly better than the saline group, but no statistically significant difference was found at 21 days. It was possible to conclude that bismuth subgallate did not interfere in the tissue repair of the palatal mastigatory mucosa in dogs.

Osseointegration of oxidized and turned implants in circumferential bone defects with and without adjunctive therapies: an experimental study on BMP-2 and autogenous bone graft in the dog mandible.

The aim of the study was to compare the integration and implant stability of turned and oxidized titanium implants when placed in experimental bone defects with autogenous bone graft, BMP-2 or without adjunctive therapy. Four defects were prepared on each side of the mandible of 12 mongrel dogs five months after tooth extractions. Implants with turned and oxidized surfaces were placed in the defects. The circumferential gaps were filled with either autogenous bone grafts, a BMP-allogeneic dog mixture in a thermoplastic carrier, carrier alone or left without any treatment (control). There were no statistically significant differences between control and treated sites, neither for turned nor for oxidized implants with regard to histomorphometric measurements in ground sections and to implant stability as measured with resonance frequency analysis (RFA) after 4 and 12 weeks of healing. However, oxidized implants showed a significantly higher stability after 4 weeks and a tendency (p < 0.1) of that after 12 weeks. Histomorphometry showed more bone contacts for oxidized than for turned implants. It is concluded that oxidized implants gain stability more rapidly and integrate with more bone contacts than implants with a turned surface when placed in bone defects.