The initial adhesion of cells to the implant surface and the subsequent behavior of the cells are important for their biocompatibility. This study investigated the continuousness of the effects of glow-discharge (GD) treatment on the adhesion of cells to titanium.
Polished titanium plates (30 mm in diameter, 2 mm in thickness) were treated with GD. Human gingival fibroblast (hGF) cells were seeded on each treated sample. After 6 h of culture, cells were fixed and stained with TRITC-phalloidin to count the number of attached cells. After 24 h of culture, the cells were fixed and incubated with antibody against vinculin to examine the formation of focal adhesion. Titanium disks were treated using GD in a plasma chamber for 20-240 s. To compare with the effects of ultraviolet (UV) treatment, the titanium disks were exposed to UV for 6-48 h. Untreated titanium disks were used as controls (CON) . The hydrophilic status of the titanium surfaces was analyzed by XPS analysis, and the wettability was examined by the spread of 5 μL of H₂O. Titanium disks treated with GD were in the air for 0-6 h after the treatment to examine the continuousness of the effects of GD treatment. The maximum wettability was observed by GD treatment for 120 s, whereas the maximum wettability by UV treatment was observed by the 48 h of UV treatment. The effect of GD decreased by half at 1 h after GD treatment and converged with the CON level at 6 h. The number of hGF cells attached to GD and UV after 6 h of incubation was significantly greater than that attached to CON. The number of vinculin immuno-positive focal adhesion per cell was significantly greater on GD and UV treated disks than on CON disks. Neither the number of attached cells nor focal adhesion formation showed significant differences between GD and UV.
These findings demonstrated that only 2 min of GD treatment on the titanium surfaces caused similar wettability and cell attachment as 48 h of UV treatment. However, the effect of GD treatment disappeared within 6 h in the air. The present study suggests that GD treatment is quite easy but titanium implants treated with GD should be used as soon as possible after GD treatment.

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Y-TZP is used in the field of dental implants mainly for abutment, and Y-TZP fixtures have already been marketed in Europe and the U.S. However, it is that Y-TZP suffers low-temperature degradation, and so shows decreased strength under hydrothermal treatment. Therefore, effects of hydrothermal processes on the low-temperature degradation of a Y-TZP were examined in this study.
Hydrothermal treatment were conducted using a special autoclave under four conditions: at 134℃ and 0.2 MPa for 5 hours (h) or 100 h; or at 180℃ and 1.0 MPa for 5 h or 20 h. Five test specimens for each condition, including a test without hydrothermal process, were prepared. Measurement was conducted using the IF method under conditions of indentation fracture load of 294 N and indentation time of 15 s. Fracture toughness values were calculated from the obtained measurement values. The test specimens after the measurements were observed under a scanning electron microscope (SEM) . Furthermore, X-ray diffractometry (XRD) was conducted to measure phase transformation caused by hydrothermal treatment. In addition, to observe differences of crystal structure, mirror polished test specimens were baked again as a thermal etching process, and then observed under SEM.
For conventional Y-TZP, surface fracture occurred under conditions of 134℃/0.2 MPa/100 h, 180℃/1.0 MPa/5 h, and 180℃/1.0 MPa/20 h; therefore, measurement could not be conducted under these conditions. The fracture toughness values of the untreated specimen and hydrothermal specimen treated at 134℃/0.2 MPa/5 h were 7.36 MPa/m^1/2 and 7.02 MPa/m^1/2, respectively. There was no significant difference between these two conditions. For the novel Y-TZP, measurements were conducted under all conditions, and fracture toughness values were between 14.98 and 15.60 MPa/m^1/2. No significant differences were observed among the conditions in the results of multiple comparisons. Results of XRD showed a notable increase of monoclinic crystals and decrease of tetragonal crystals at 134℃/100 h, 180℃/5 h, and 180℃/120 h by the conventional Y-TZP. The novel Y-TZP indicated a smaller increase of monoclinic crystals and minimal decrease of tetragonal crystals. In the novel Y-TZP, zirconia grains and sparse alumina grains were observed by SEM observation.
The results of this study indicated that the novel Y-TZP has a higher fracture toughness value and not lowtemperature degradation than conventional Y-TZP.

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Purpose: The purpose of this study was to investigate the expression of involucrin and filaggrin in the peri-implant epithelium(PIE) .
Materials and Methods: Titanium implants, 2 mm in diameter and 5 mm in length, were surgically implanted in the palatal region of rats. Animals were sacrificed at 3, 7, 14 and 28 days after the implantation. Paraffin sections were cut, and hematoxylin-eosin and immunohistochemical staining was performed using primary antibodies to involucrin and filaggrin.
Results: Involucrin in the PIE immunoreacted with almost all epithelial cells except basal cells 3 days after implantation, but was positive only in the upper area of the spinous layer at 7, 14 and 28 days after implantation. Further, involucrin-positive cells could be observed in the apical portion of the PIE at 3 and 7 days after implantation, but not at 14 and 28 days. The measurement of the involucrin ratio decreased day by day. Filaggrin immunoreacted at the upper portion of the spinous layer of normal oral mucosal epithelium, but not in the entire layer of PIE at 3, 7 and 14 days or in the apical portion of the PIE at 28 days after implantation.
Conclusion: The PIE in the apical portion is structured by basal cells which contact the implant material, but the barrier function of the cornified layer does not function well at an early stage.

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Objectives: To investigate so-called lingual foramina (LF), which is important for surgery in the anterior portion of the mandible, using various imaging modalities.
Materials and Methods: Twenty-one consecutive patients who underwent intraoral radiography or intraoral source panoramic radiography and multi detector computed tomography (MDCT) or cone-beam computed tomography (CBCT) in the anterior portion of the mandible for various diseases were examined for the presence, number, location, direction, distance of LF to the alveolar crest, and depth of LF.
Results: LF was detected in only MDCT or CBCT. The numbers of LF were 1(8 out of 21, 38%), 2(8 out of 21, 38%), 3 (3 out of 21, 14%) and 4 (2 out of 21, 10%). The horizontal locations were in the midline (66%) , right side (17%), and left side (17%). The vertical directions were upwards (42%) , downwards (32%) , and horizontal (27%), respectively. The most common distance to the alveolar crest was“between 20 mm and 25 mm,” whereas the most common depth was“2 mm to 3 mm.”
Conclusions: MDCT or CBCT may be needed to detect LF. In particular, CBCT is recommended from the viewpoint of radiation exposure to patients. Our study suggested that the numbers of LF tend to be larger than previously reported, and so operators should interpret CT images in detail.

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This clinical case report describes a case of bilateral partial edentulism in the posterior mandible with skeletal mandibular protrusion. The patient was a 43-year-old woman with the chief complaint of masticatory and cosmetic disturbance. In this case, dental implants were used to anchor non-surgical orthodontics. Three dental implants were placed in the posterior mandible, then orthodontic treatment was carried out using these dental implants as orthodontic anchors. In addition, orthodontic mini-screws were placed for vertical intrusion of lower anterior teeth. After correction of reversed occlusion of anterior teeth and extrusive upper and lower teeth, the final implant-supported superstructure was inserted. Implant prostheses and oral hygiene were maintained in excellent condition during 3 years of follow-up.

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We present a case of malignant lymphoma of the mandible diagnosed by coincidentally-developed mental hypoesthesia after placement of a dental implant. A 60-year old woman who underwent dental implant placement by a dental practitioner visited our hospital because of postoperative mental hypoesthesia. Orthopantomography and CT revealed perforated bone defects at the posterior molar and ramus region of the mandible, but could not demonstrate a causal relationship between the implantation and the hypoesthesia. In blood test results, the values of sIL-2R and LDH were abnormally elevated. A tumor arising from soft tissue around the molar region was biopsied, and a diagnosis of diffuse large B-cell lymphoma was confirmed histopathologically. This tumor was treated at the Department of Hematology by the R-CHOP chemotherapy regimen, resulting in complete remission of the tumor, and masticatory function was adequately restored using dental implants. It was concluded that early detection and rapid cure are the key to maintaining oral function.

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A questionnaire survey was conducted to determine the information required by patients prior to providing informed consent for dental implant surgery. Questionnaires were distributed to 1,585 patients who visited the Tokyo Medical and Dental University Hospital for oral implants between January 2012 and December 2012, of which 1,159 (73%) valid questionnaires were collected. The results showed that preservation of an adjacent tooth was the reason that 32% of participants chose implant therapy. Over 70% of participants indicated that their main concerns regarding implant therapy were aftereffects of surgery, the number of years the implants would be in place, and treatment cost. Regarding knowledge about implant therapy, patients' most frequent reply was“ I do not know” when asked about postoperative pain, peri-implantitis, the importance of implant maintenance, and the relationship between general health and implant therapy. Fifty-nine percent of the patients recognized smoking as a risk factor for periodontal disease, of which 23% recognized smoking as a risk factor for implant therapy. Sixty-one percent of patients replied“ more than 20 years” when asked about the number of years that they believed the implants would be in place. This research identified the information required by patients in order to provide informed consent. Comprehensive information is required before informed consent is sought, as the majority of patients did not possess sufficient knowledge regarding implant therapy.

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