A review of the recent literature on maxillary overdenture with dental implants.

The recent literature on maxillary implant overdenture (IOD) was reviewed in order to clarify its predictability and establish treatment guidelines. Electronic searches were performed using PubMed, and articles about maxillary IOD written after 1990 were reviewed, focusing on the following items: I. implant survival rate, II. maxillary IOD survival rate, III. number of implants, IV. attachment type, V. follow-up period, VI. implant system, and VII. opposing dentition. The review revealed an implant survival rate of 61-100% and an overdenture survival rate of 72.4-100%. The attachments used included bars, balls, locators, and telescope crowns. The minimum and maximum observation periods were 12 months and 120 months, respectively, and the number of implants used for supporting IOD ranged from 2 to 8. At present, there is no strong evidence to indicate that maxillary IOD is clearly superior for all the items examined. However, the existing data indicate that maxillary IOD has almost the same therapeutic effect as fixed implant superstructures, and is a treatment option that can be actively adopted for patients in whom fixed superstructures cannot be applied for various reasons.

Uptake of Nanotitania by Gingival Epithelial Cells Promotes Inflammatory Response and Is Accelerated by Porphyromonas gingivalis Lipopolysaccharide: An In Vitro Study.

Titanium is often used in the medical field and in dental implants due to its biocompatibility, but it has a high rate of leading to peri-implantitis, which progresses faster than periodontitis. Therefore, in the present study, the expression of cytokines from gingival epithelial cells by nanotitania was investigated, which is derived from titanium in the oral cavity, and the additional effect of Porphyromonasgingivalis (periodontopathic bacteria) lipopolysaccharide (PgLPS) was investigated. Ca9-22 cells were used as a gingival epithelial cell model and were cultured with nanotitania alone or with PgLPS. Cytokine expression was examined by reverse transcription-quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. In addition, cellular uptake of nanotitania was observed in scanning electron microscopy images. The expression of interleukin (IL)-6 and IL-8 significantly increased in Ca9-22 cells by nanotitania treatment alone, and the expression was further increased by the presence of PgLPS. Nanotitania was observed to phagocytose Ca9-22 cells in a dose- and time-dependent manner. Furthermore, when the expression of IL-11, related to bone resorption, was investigated, a significant increase was confirmed by stimulation with nanotitania alone. Therefore, nanotitania could be associated with the onset and exacerbation of peri-implantitis, and the presence of periodontal pathogens may worsen the condition. Further clinical reports are needed to confirm these preliminary results.

Applications of three-dimensional printers in prosthetic dentistry.

This narrative review aims to provide an overview of recent studies and case reports on three-dimensional (3D) printing, and to verify the applicability of 3D printers in the field of dental prostheses. This review was performed by conducting a search of PubMed. The clinical application of fabricating a prosthesis made with cobalt-chromium is considered possible depending on the material and hardware of the 3D printer. However, it is currently difficult to assess the clinical use of 3D-printed zirconia crowns. Further research is required, such as verification of materials used, margin morphology, and hardware. Clinically acceptable results have been reported for patterns using 3D printers. Interim restorations made using a 3D printer have been reported with good results that are considered clinically usable. Dentures made with 3D printers need further verification in terms of strength and deformation. Custom trays made with 3D printers are clinically useful, however, issues remain with design time and effort. Although several studies have reported the usefulness of 3D printers, further verification is required since 3D printers are still considered new technology.

Titanium nanoparticles potentially affect gingival tissue through IL-13α2 receptor expression.

PURPOSE: To determine the effects of titanium nanoparticles, that may have been scattered after dental implant placement, on gene and promoter expression, and gingival tissue. METHODS: Ca9-22 cell lines were used as gingival epithelial cells to assess the effects of titanium dioxide nanomaterials as titanium nanoparticles. Cells were cocultured with or without titanium dioxide nanomaterials prior to gene and promoter expression analysis. Expression of interleukin-13α2 receptor was investigated using real-time quantitative reverse-transcription polymerase chain reaction and immunofluorescence staining. Additionally, the enhanced messenger ribonucleic acid (mRNA) expression of transforming growth factor ß1 was analyzed using the same method. RESULTS: Titanium dioxide nanomaterials affected gene and promoter expression in Ca9-22 cells: among the 160 upregulated genes, the upregulation of IL13RA2, which encodes interleukin-13α2 receptor, was the highest (8.625 log2 fold change). Immunofluorescence staining confirmed the increased expression of interleukin-13α2 receptor, which enhanced transforming growth factor ß1 expression by stimulation with interleukin-13. CONCLUSION: Titanium dioxide nanomaterials applied on the gingival epithelium around the dental implant may increase interleukin-13α2 receptor expression. In turn, this can enhance the secretion of transforming growth factor ß1, which is known to promote the differentiation of osteoclasts involved in bone resorption, and potentially affect gingival tissue.

Establishment of Epithelial Attachment on Titanium Surface Coated with Platelet Activating Peptide.

The aim of this study was to produce epithelial attachment on a typical implant abutment surface of smooth titanium. A challenging complication that hinders the success of dental implants is peri-implantitis. A common cause of peri-implantitis may results from the lack of epithelial sealing at the peri-implant collar. Histologically, epithelial sealing is recognized as the attachment of the basement membrane (BM). BM-attachment is promoted by activated platelet aggregates at surgical wound sites. On the other hand, platelets did not aggregate on smooth titanium, the surface typical of the implant abutment. We then hypothesized that epithelial BM-attachment was produced when titanium surface was modified to allow platelet aggregation. Titanium surfaces were coated with a protease activated receptor 4-activating peptide (PAR4-AP). PAR4-AP coating yielded rapid aggregation of platelets on the titanium surface. Platelet aggregates released robust amount of epithelial chemoattractants (IGF-I, TGF-ß) and growth factors (EGF, VEGF) on the titanium surface. Human gingival epithelial cells, when they were co-cultured on the platelet aggregates, successfully attached to the PAR4-AP coated titanium surface with spread laminin5 positive BM and consecutive staining of the epithelial tight junction component ZO1, indicating the formation of complete epithelial sheet. These in-vitro results indicate the establishment of epithelial BM-attachment to the titanium surface.

[Incidence of taste disorder associated with cancer patients undergoing chemotherapy on an ambulatory basis].

Taste disorders are a common complaint among cancer patients undergoing chemotherapy on an ambulatory basis. We conducted a survey on the incidence of such disorders among 74 patients, and 45.95% (34 of 74 patients) developed taste disorders. When stratified by medication into a regimen including 5-FU and one including taxanes, taste disorders were found in 59.0% (23 of 39 patients) of the former and 60.0% (9 of 15) of the latter. The survey also included the effects of taste disorders on patients appetites. Both regimens led to reduced appetite in a number of these patients (39.1% and 44.4%, respectively). Among patients on the 5-FU-containing regimen, the FOLFOX/FOLFIRI therapy was found to be responsible for loss of appetite. Regarding change in tastes, many patients stated that the medication dulled their taste sensation except for bitterness; their capacity to sense intensity of taste remained unchanged. It was found that acute taste disorders develop frequently among patients on a high dosage of 5-FU or a taxane-containing regimen.

[Development of taste disorders following FOLFOX-FOLFIRI therapy and its effects on the QOL of patients with colorectal cancer].

Taste disorders are frequent occurrences among those patients under the FOLFOX-FOLFIRI regimen for colorectal cancer. We conducted a study on the development of taste disorders among colorectal cancer patients under this regimen and the effect of such disorders on their QOL. Taste disorders occurred in 58.1%(18/31 cases)of these patients and the disorders affected appetites in 50%(9 cases). The changes in taste sensations were subtle in most but some described certain tastes as exaggerated. Others reported changes in all taste sensations, including sweet, salty, bitter and sour, as well as deliciousness. When tested via the QOL Survey Sheet(Quality of Life Questionnaire for Cancer Patients Treated with Anticancer Drugs: QOL-ACD), the QOL was found to have deteriorated significantly in those who stated that taste disorders affected their appetite, in comparison with those who were unaffected. In patients with colorectal cancers and treated with the FOLFOX-FOLFIRI regimen, taste disorders are frequent occurrences. The poor nutritional state due to a loss of appetite may constitute a factor responsible for a lowering QOL.

[Prevention of oxaliplatin-related neurotoxicity by glutathione infusions].

We have used glutathione for prevention of oxaliplatin-related neurotoxicity with reference to the article of Cascinu et al. We investigated oxaliplatin-related neurotoxicity in Kariya Toyota General Hospital(KTGH)and compared with the data described in the article of Gamelin about the severity of its neurotoxicity. Grade 3 neurotoxicity was observed in only 5 of 44 patients(11.4%). The median number of cycles and cumulative dose of oxaliplatin were 12 cycles(5-27 / cycles)and 802.2(273.2-1,952.4)mg/m(2), respectively, at Grade 3 neuropathy. We evaluated retrospectively neuro-toxicity grade at cumulative oxaliplatin doses of approximately 500-520 mg/m(2). The severity of neurotoxicity observed in KTGH was significantly lower than in the group without Ca/Mg. We found no difference between the group with glutathione and / with Ca/Mg. Glutathione infusions seemed to prevent oxaliplatin-related neurotoxicity.