Identification of Candida dubliniensis in a study of HIV-seropositive pediatric dental patients

PURPOSE: The combination of an immature immune system and suppressed cellular immunity in children with HIV infections provides optimal conditions for rapid disease progression. As a result, pediatric AIDS has become a major epidemiological challenge. Oral fungal colonization remains one of the most common opportunistic infections observed in both adult and pediatric HIV infected patients. Although Candida albicans is the most frequently isolated opportunistic fungal species, a recently characterized Candida species, C. dubliniensis, has gained considerable attention due to its almost exclusive association with HIV-seropositive individuals. The purpose of this study was to prospectively screen for the presence of C. dubliniensis among pediatric HIV+ patients. METHODS: Oral samples taken from twenty-seven children were cultured for the presence of yeast. All positive yeast isolates obtained were screened for the presence of C. dubliniensis by use of tests for germ tube and chlamydospore production, detection of inability to grow at 45 degrees C, by colony color on CHROMagar Candida medium, coaggregation with Fusobacterium nucleatum ATCC 49256 and by the results of sugar assimilation testing with the API 20C AUX yeast identification system. RESULTS: Among the 27 patients tested, 3 patients were found to harbor C. dubliniensis, one of which also grew C. glabrata; 12 patients were colonized with C. albicans, while the remaining 12 patients were negative for yeast. Identification of the three C. dubliniensis isolates was genetically confirmed by electrophoretic karyotyping. All three C. dubliniensis isolates were found to be susceptible to fluconazole (MIC < or = 0.25 ug/ml). CONCLUSIONS: These results confirm the presence of this novel species in a dental pediatric HIV seropositive population and support the need for further investigation into the prevalence and pathogenesis of C. dubliniensis.     

Effects of transforming growth factor beta1 (TGFbeta-1) and dentin non-collagenous proteins (DNCP) on human embryonic ectomesenchymal cells in a three-dimensional culture system

Cranial neural crest-derived ectomesenchymal cells represent a population of pluripotent stem cells giving rise to many of the various oro-facial and dental tissues. The factors determining the terminal fate of these cells are still unclear. The potentiality of human embryonic ectomesenchymal cells from the first branchial arch have been investigated when isolated and grown in a three-dimensional (3D)-collagen gel culture system in the presence of dentin matrix-derived non-collagenous proteins (DNCP) and TGFbeta-1. Functional differentiation of cells showing some characteristics of odontoblast-like cells could be observed when the cells were cultured with DNCP+TGFbeta-1 or DNCP, however, only cytological differentiation was observed during culture with TGFbeta-1 alone. The characteristics of these cells was assessed by morphological appearance, expression of the odontoblast phenotype marker dentin sialophosphoprotein (DSPP), increased alkaline phosphatase levels and formation of mineralised nodules in vitro. The results indicate that these embryonic cells from the first branchial arch are capable of responding to the inductive stimulus of DNCP or DNCP+TGFbeta-1 when isolated and grown in the 3D collagen gel culture system. The capacity of the isolated cells to differentiate into mineralizing cells showing some characteristics of odontoblast-like cells under these growth conditions highlights the potential of such approaches for tissue engineering strategies for hard-tissue regeneration after injury.     

A study of Streptococcus mutans levels in both infants with bottle caries and their mothers

A bstract — A relationship was sought between the rampant form of caries in infants known as bottle caries and Streptococcus mutans levels in both these infants and their mothers. Streptococcus mutans scores in children with active bottle caries were high. Mothers' and children's scores were significantly related, providing a basis for further studies of efficient primary prevention.     

Dentin adhesion and microleakage of a resin-based calcium phosphate pulp capping and basing cement

An experimental resin-based bioactive calcium phosphate cement, intended as a pulp capping and basing material, was evaluated for dentin shear bond strength and microleakage. The interfacial morphology was examined by scanning electron microscopy (SEM). For microleakage, dentin cavities without (Group A) or after (Group B) acid etching were restored with the calcium phosphate cement. A resin-based calcium hydroxide (VLC Dycal; Group C) was used as control material according to the manufacturer's instructions. After water storage and thermocycling, the microleakage was scored using a AgNO(3) staining procedure. For the shear bond strength, flat exposed dentin surfaces were treated as for the microleakage test. Metal irises pressed against the dentin surface were filled with the cements, which were photocured. Both tests were carried out after 1 wk. While acid etching did not result in significantly greater microleakage, it led to higher shear bond strength, and allowed, as shown by SEM, the formation of a hybrid layer and resin tags. Both groups treated with the calcium phosphate cement had significantly lower microleakage scores and higher mean shear bond strength values than the groups treated with the control material.     

Intraosseous anesthesia: a review

The recent introduction of intraosseous injection devices has renewed interest in the modality of local anesthesia. Three devices currently available are the Stabident System, the Hypo Brand Intraosseous Needle, and the Cyberjet System. The Stabident System is the most popular and the only one for which published research is available. Primary intraosseous anesthesia is 45 percent to 93 percent effective but of short duration. Supplemental intraosseous anesthesia is 80 percent to 90 percent effective and provides profound anesthesia of long duration (60 minutes or longer). It is used when a prior conventional infiltration or nerve block is inadequate. During use of an anesthetic solution with a vasoconstrictor for intraosseous anesthesia, 46 percent to 100 percent of patients reported an increase in heart rate. There was a 2 percent to 27 percent incidence of moderate and sometimes severe pain during the intraosseous procedure. Postoperative complications occurred in 2 percent to 15 percent of patients and lasted one to 14 days.     

Dental amalgam. Designs for research in human populations

Questions have been raised about the safety of dental amalgam. The main point of contention is whether the mercury contained in dental restorations is released in sufficient quantities to pose a public health hazard. Most scientists agree that current evidence is not sufficient to show that amalgam restorations pose a general health threat. But researchers on both sides of this debate agree that much remains to be learned about any potential toxicity of dental amalgam--an issue serious enough to merit additional research.     

A CAD-CAM Ceramic Inlay Technique

This article details the technique of a Cerec computer-aided designed (CAD) and computer-aided manufactured (CAM) inlay. Using a ceramic material the unit can mill an inlay from an optical "impression" that is then bonded to place using a dual-cure composite resin cement.