Salivary immunoglobulin A and G subclasses in HIV positive patients.

Many of the opportunistic infections in HIV are related to the mucous membranes, but the protection of oral mucosal compartment mediated by IgA and IgG subclasses in saliva is still not well documented. Therefore, the aim of this study was to investigate the status of salivary IgA and IgG subclass in HIV positive patients. Levels of IgG1, IgG2, IgG3 and IgG4 were determined by ELISA and IgA1 and IgA2 by radial immunodiffusion in the resting whole saliva of 33 HIV patients and 21 HIV-seronegative healthy controls and were expressed in mg/L (IgA) and ug/L (IgG) of saliva. Salivary IgA2 was significantly reduced in the HIV positive patients (p<0.0009) when compared to the healthy controls, but no differences in salivary IgA1 level between HIV patients and healthy controls were found. On the other hand, salivary IgG1, IgG2, IgG3 and IgG4 subclasses were increased (p<0.0009) in HIV patients in comparison to the healthy controls. We can conclude that inspite of IgA2 deficiency which was found in studied HIV positive patients, mucosal antibody responses are quite normal and might not predispose development of oral opportunistic infections.

Changes in dentin after insertion of self-threading titanium pins with 3 methods: a scanning electron microscope pilot study.

STATEMENT OF PROBLEM: Inserting a self-threading pin can cause dentinal cracks, but it is not known whether dentin bonding agents can penetrate these cracks. PURPOSE: Part I of this in vitro pilot study was conducted to document the presence of dentinal cracks after the placement of self-threading pins with 3 methods. Part II was conducted to observe changes in dentin when a dentin bonding agent was applied before insertion of the self-threading pins. MATERIAL AND METHODS: The crowns of 14 noncarious third molars were sectioned horizontally 2 mm above the cemento-enamel junction, and the occlusal portions were discarded. The teeth were put into a nontransparent bag and divided randomly into 2 groups. Group 1 consisted of 12 teeth. In each tooth, 4 pinholes were prepared with a handpiece at normal rotation speed (30,000 rpm). Self-threading pins were placed into 3 of the pinholes in each tooth: 1 manually, 1 by handpiece at 7000 rpm, and 1 by handpiece at 30,000 rpm. The fourth pinhole was left empty and served as the control. All group 1 teeth were sectioned vertically through the pins, dental hard tissue, and control pin holes. The examination surface of each specimen in group 1 was polished, and the smear layer was removed with Calcinase and NaOCl solutions. After dehydration in ascending grades of alcohol, specimens were coated with a 10- to 15-nm-thick layer of gold and examined with a scanning electron microscope. In the remaining 2 teeth (group 2), a dentin bonding agent was introduced into the pinholes prior to pin placement. Two pins were placed manually and 2 by handpiece at 30,000 rpm. After pin placement, sectioning, cleaning, and dehydration, the specimens were examined with a scanning electron microscope, and x-ray mapping was performed to determine the presence of titanium, silicon, and calcium. RESULTS: Craze lines in dentin were associated with 54.5% of pins placed manually and 54.5% of pins placed with a handpiece at reduced speed (7000 rpm). Dentinal cracks were associated with 50% of pins placed with a handpiece at standard speed and with 16.7% of the control pinholes. X-ray mapping analysis revealed the presence of the dentin bonding agent between the pin and dentin wall. The dentin bonding agent was not found in the dentinal cracks except at the crack orifice. SUMMARY: Within the limitations of this pilot study, the method of pin insertion had no direct bearing on the presence of dentinal cracks. The dentin bonding agent tested did not fill the entire space of dentinal cracks but did occlude their orifices and fill the spaces between pin surface and dentin walls in the pin preparation.