In Vitro Study of Zirconia Surface Modification for Dental Implants by Atomic Layer Deposition.

Zirconia is a promising material for dental implants; however, an appropriate surface modification procedure has not yet been identified. Atomic layer deposition (ALD) is a nanotechnology that deposits thin films of metal oxides or metals on materials. The aim of this study was to deposit thin films of titanium dioxide (TiO2), aluminum oxide (Al2O3), silicon dioxide (SiO2), and zinc oxide (ZnO) on zirconia disks (ZR-Ti, ZR-Al, ZR-Si, and ZR-Zn, respectively) using ALD and evaluate the cell proliferation abilities of mouse fibroblasts (L929) and mouse osteoblastic cells (MC3T3-E1) on each sample. Zirconia disks (ZR; diameter 10 mm) were fabricated using a computer-aided design/computer-aided manufacturing system. Following the ALD of TiO2, Al2O3, SiO2, or ZnO thin film, the thin-film thickness, elemental distribution, contact angle, adhesion strength, and elemental elution were determined. The L929 and MC3T3-E1 cell proliferation and morphologies on each sample were observed on days 1, 3, and 5 (L929) and days 1, 4, and 7 (MC3T3-E1). The ZR-Ti, ZR-Al, ZR-Si, and ZR-Zn thin-film thicknesses were 41.97, 42.36, 62.50, and 61.11 nm, respectively, and their average adhesion strengths were 163.5, 140.9, 157.3, and 161.6 mN, respectively. The contact angle on ZR-Si was significantly lower than that on all the other specimens. The eluted Zr, Ti, and Al amounts were below the detection limits, whereas the total Si and Zn elution amounts over two weeks were 0.019 and 0.695 ppm, respectively. For both L929 and MC3T3-E1, the cell numbers increased over time on ZR, ZR-Ti, ZR-Al, and ZR-Si. Particularly, cell proliferation in ZR-Ti exceeded that in the other samples. These results suggest that ALD application to zirconia, particularly for TiO2 deposition, could be a new surface modification procedure for zirconia dental implants.

Effects of heated tobacco products and conventional cigarettes on dental implant wound healing: experimental research.

Smoking affects wound healing and is associated with dental implant failure. Heated tobacco products (HTPs) appear to be less harmful than conventional cigarettes (CCs); however, there is limited analytical data to support this claim. This study aimed to compare HTPs and CCs for their impact on wound healing using L929 mouse fibroblast cells and evaluate whether HTPs also lead to failure in implant therapy. Materials and methods: Cigarette smoke extract (CSE) was obtained from CCs (Marlboro, Philip Morris) and HTPs (Marlboro Heat Sticks Regular for IQOS, Philip Morris) and initiated a wound-healing assay with a cell-free area created in the centre of a titanium plate by sticking a 2-mm-width line tape. The L929 mouse fibroblast cells were exposed with 2.5 and 5% CSE from HTPs and CCs and then seeded in the titanium plate. A scratch wound-healing assay was initiated when all samples were at 80% confluence. The number of cells migrating to the wound site was counted after 12, 24, and 48 h. Results: Cell migration decreased after CSE exposure from both CCs and HTPs. At each time-point with 2.5% CSE, cell migration in the HTP group was less than that of the CC group. There were significant differences between the 2.5% CC and 2.5% HTP groups and the 5% CC and 5% HTP groups after 24 h. HTPs and CCs had similar effects in the wound-healing assay. Conclusion: Therefore, HTP use may be a risk factor for poor dental implant healing.

Cytotoxic, genotoxic, and toxicogenomic effects of heated tobacco products and cigarette smoke in human primary keratinocytes.

INTRODUCTION: Heated tobacco products (HTPs) appear to be less harmful to health than conventional cigarettes (CCs). However, limited analytical data are available to support this claim. This study aimed to compare the cytotoxic, genotoxic, and toxicogenomic effects of HTPs and CCs in carcinogenesis via multistep gene mutations in the oral mucosal cells. METHODS: Cigarette smoke extract (CSE) was obtained from HTPs and CCs. Primary human oral keratinocytes (HOKs) were treated with 5% and 20% CSE from HTPs and CCs. Cell survival rate assays were performed after 6, 12, and 24 h. After 6 h, DNA double-strand breaks (DSBs) were evaluated using anti-γH2AX antibodies with immunohistochemistry. mRNAs expressions of mediator of DNA damage checkpoint 1 (MDC1) and ataxia telangiectasia and Rad3-related protein (ATR), were analyzed. Expressions of miR-22 and miR-185 were analyzed because miR-22 targets MDC1 and miR-185, ATR. RESULTS: The HOKs had equivalent survival rates after exposure to the same concentrations of CSE from CCs and HTPs. HTPs increased foci formation of γH2AX in HOKs, as did CCs (without CSE vs 20% HTP, p<0.05; without CSE vs 20% CC, p<0.05). Expressions of MDC1 and ATR decreased in cells exposed to CSE from CCs and HTPs (MDC1: without CSE vs 20% HTP, p<0.05; without CSE vs 20% CC, p<0.05; ATR: without CSE vs 20% HTP, p<0.05; without CSE vs 20% CC, p<0.05). Expressions of miR-22 and miR-185 were not significantly increased when exposed to CSE from CCs or HTPs. CONCLUSIONS: HTPs and CCs had similar cytotoxic effects. HTPs are genotoxic, can cause DSBs, and have toxicogenomic damage because they inhibit the MDC1 and ATR-CHK1 DNA repair pathways in the oral mucosa. The miRNA-mRNA axis was not related to these inhibitions.

Secondary Squamous Cell Carcinoma of the Tongue Complicated with Bronchiolitis Obliterans as a Manifestation of Graft-versus-Host Disease following Peripheral Blood Stem Cell Transplantation.

Peripheral blood stem cell transplantation (PBSCT) has increasingly been used for hematologic cancer therapy, resulting in improved survival rates. However, risks include graft-versus-host disease (GVHD) and secondary solid tumors. Here, we describe a case of tongue squamous cell carcinoma (SCC) complicated by bronchiolitis obliterans (BO) following PBSCT. A 42-year-old man with a history of acute lymphocytic leukemia treated with PBSCT presented with multiple white lesions and erosions on the tongue and buccal mucosa that are compatible with oral chronic GVHD (NIH criteria: score 2). The lesions were presented for 8 years. The patient had a history of BO manifested as GVHD. During follow-up, an exophytic mass was rapidly developed on the left dorsum of the tongue. Biopsy of this lesion confirmed SCC (cT2N0M0). Pulmonary function testing for general anesthesia was almost normal. Hemiglossectomy, supraomohyoid neck dissection, and tongue reconstruction were performed. Thirteen months after surgery, the patient showed neither recurrence of tumor nor progression of oral GVHD. However, the patient died of respiratory failure due to repeated pneumothoraxes and deterioration of BO.

Drug-induced hypersensitivity syndrome due to mexiletine hydrochloride associated with reactivation of human herpesvirus 7.

It has been suggested that reactivation of human herpesvirus 6 (HHV-6) infection may be involved in the pathogenesis of drug-induced hypersensitivity syndrome. We report a 45-year-old Japanese man who developed a generalized papuloerythematous rash, fever, hepatitis, lymphadenopathy and lymphocytosis with an increased number of atypical lymphocytes. He was diagnosed with DIHS due to mexiletine hydrochloride based on laboratory data, results of a patch test and the clinical course of his complaint, and was treated with systemic steroids. In order to determine whether HHV-6 or -7 was associated with the patient's disease, serological assays and PCR were carried out. Significant increases in antibody titers against HHV-6 and -7 were observed from day 12 to 24. From PCR analysis, none of the peripheral blood mononuclear cells or skin tissue samples contained HHV-6 DNA. All samples, however, were found to contain HHV-7 DNA. Reactivation of HHV-7 could be responsible for drug-induced hypersensitivity syndrome.

[Intravascular ultrasound and angioscopy].

We observed pulmonary artery thrombi and parietal lesions in patients with acute pulmonary thromboembolism (APTE), using intravascular ultrasound (IVUS) and angioscopy (AS). In APTE without underlying disease mainly non-echorich intraluminal mass was noted, with a pulsatile and thin intima. On AS red thrombi with white fibrin coating could be directly observed, and no parietal lesions were found. The findings of the pulmonary arterial intima and thrombus were different between APTE and chronic pulmonary thromboembolism (CPTE), and even among CPTE cases. IVUS and AS are useful in characterizing the thrombi and related pulmonary artery lesions in PTE.