Evaluation of Glazing and Polishing Systems for Novel Chairside CAD/CAM Lithium Disilicate and Virgilite Crowns.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of glazing, two zirconia, and two lithium disilicate polishing systems on surface roughness of a CAD/CAM lithium disilicate and virgilite ceramic with atomic force microscopy (AFM) and visual assessment performed by dental students and faculty. METHODS AND MATERIALS: Sixty maxillary right central incisor crowns made of a novel chairside CAD/CAM lithium disilicate and virgilite (CEREC Tessera) were milled for glazing and polishing. The crowns were divided into six groups: no polishing/glazing provided (NoP/G); glazed (GZ); glazed and polished with Brasseler Dialite LD Lithium Disilicate (DiLD); glazed and polished with Meisinger Luster Lithium Disilicate (LuLD); glazed and polished with Brasseler Dialite ZR Zirconia (DiZR); and glazed and polished with Meisinger Luster Zirconia (LuZR). Surfaces were scanned with AFM to measure roughness (Ra) and root mean square roughness (Rq) and generate micrographs. Crowns were visually assessed by 10 dental students and 10 dental school faculty members to determine clinical acceptableness. RESULTS: Glazing and all polishing kits significantly reduced Ra and Rq compared to no polishing/glazing. No significant Ra differences were found between glazing and all polishing kits (p>0.05). DiZR significantly reduced Rq compared to other groups (p<0.05). Visual assessment showed that GZ, LuLD, and DiZR were the most clinically acceptable crowns. CONCLUSION: Polishing and glazing considerably improve the surface smoothness of maxillary central incisor crowns fabricated out of a chairside CAD/CAM lithium disilicate and virgilite ceramic. Altogether, zirconia polishing systems provided smoother and more clinically acceptable surfaces than the lithium disilicate kits.

Polyamine metabolism impacts T cell dysfunction in the oral mucosa of people living with HIV.

Metabolic changes in immune cells contribute to both physiological and pathophysiological outcomes of immune reactions. Here, by comparing protein expression, transcriptome, and salivary metabolome profiles of uninfected and HIV+ individuals, we found perturbations of polyamine metabolism in the oral mucosa of HIV+ patients. Mechanistic studies using an in vitro human tonsil organoid infection model revealed that HIV infection of T cells also resulted in increased polyamine synthesis, which was dependent on the activities of caspase-1, IL-1ß, and ornithine decarboxylase-1. HIV-1 also led to a heightened expression of polyamine synthesis intermediates including ornithine decarboxylase-1 as well as an elevated dysfunctional regulatory T cell (TregDys)/T helper 17 (Th17) cell ratios. Blockade of caspase-1 and polyamine synthesis intermediates reversed the TregDys phenotype showing the direct role of polyamine pathway in altering T cell functions during HIV-1 infection. Lastly, oral mucosal TregDys/Th17 ratios and CD4 hyperactivation positively correlated with salivary putrescine levels, which were found to be elevated in the saliva of HIV+ patients. Thus, by revealing the role of aberrantly increased polyamine synthesis during HIV infection, our study unveils a mechanism by which chronic viral infections could drive distinct T cell effector programs and Treg dysfunction.

Oral immune dysfunction is associated with the expansion of FOXP3+PD-1+Amphiregulin+ T cells during HIV infection.

Residual systemic inflammation and mucosal immune dysfunction persist in people living with HIV, despite treatment with combined anti-retroviral therapy, but the underlying immune mechanisms are poorly understood. Here we report that the altered immune landscape of the oral mucosa of HIV-positive patients on therapy involves increased TLR and inflammasome signaling, localized CD4+ T cell hyperactivation, and, counterintuitively, enrichment of FOXP3+ T cells. HIV infection of oral tonsil cultures in vitro causes an increase in FOXP3+ T cells expressing PD-1, IFN-γ, Amphiregulin and IL-10. These cells persist even in the presence of anti-retroviral drugs, and further expand when stimulated by TLR2 ligands and IL-1ß. Mechanistically, IL-1ß upregulates PD-1 expression via AKT signaling, and PD-1 stabilizes FOXP3 and Amphiregulin through a mechanism involving asparaginyl endopeptidase, resulting in FOXP3+ cells that are incapable of suppressing CD4+ T cells in vitro. The FOXP3+ T cells that are abundant in HIV-positive patients are phenotypically similar to the in vitro cultured, HIV-responsive FOXP3+ T cells, and their presence strongly correlates with CD4+ T cell hyper-activation. This suggests that FOXP3+ T cell dysregulation might play a role in the mucosal immune dysfunction of HIV patients on therapy.

Students' satisfaction with electrical handpieces in an educational setting.

OBJECTIVE: This article presents the evaluation and outcome of improvements carried out at Case Western Reserve School of Dental Medicine (CWRU) based on feedback provided by students during implementation of electrical handpieces technology in the school. METHODOLOGY: Students were surveyed in February 2010 (first survey) regarding their satisfaction with the existing clinical set-up for electrical handpieces. Following a change in clinical setting and integration of the control box into the dental unit in November 2010, students were administered the same survey as in February 2010 (second survey). RESULTS: There was an increased level of satisfaction with electric handpieces in the new clinical setting; these levels were significant regarding the ergonomics of the handpiece and clinical setting, operation of the handpiece, and technical maintenance. There was a significant shift from those who were categorically against using electrical handpieces after graduation towards those were 'not sure' regarding the adoption of electric technology in their practice. CONCLUSIONS: Specifically improving the clinical setting of a control box for electrical handpieces can influence overall student perception regarding the quality of handpieces and their operation.

Antifungal resistance of candidal biofilms formed on denture acrylic in vitro.

Denture biofilms represent a protective reservoir for oral microbes. The study of the biology of Candida in these biofilms requires a reliable model. A reproducible model of C. albicans denture biofilm was developed and used to determine the susceptibility of two clinically relevant C. albicans isolates against 4 antifungals. C. albicans, growing as a biofilm, exhibited resistance to amphotericin B, nystatin, chlorhexidine, and fluconazole, with 50% reduction in metabolic activity (50% RMA) at concentrations of 8, 16, 128, and > 64 microg/mL, respectively. In contrast, planktonically cultured C. albicans were susceptible (50% RMA for the same antifungals was obtained at 0.25, 1.0, 4.0, and 0.5 microg/mL, respectively). In conclusion, results obtained by means of our biofilm model show that biofilm-associated C. albicans cells, compared with cells grown in planktonic form, are resistant to antifungals used to treat denture stomatitis.

Clinical implications of drugs taken by our patients.

An awareness of the various medications commonly prescribed for patients to self-administer will assist clinicians to anticipate the most commonly encountered medical diagnoses; will give clues to a patient's physical and emotional ability to undergo and respond to dental care; will alert clinicians to potential drug-drug and drug-disease interactions, and to the presence of drug-induced illness; and provide invaluable information that will help the clinician identify high-risk patients who may experience a life-threatening medical emergency while in the dental office.