It was demonstrated that periodontopathic bacteria including ‘red complex species’ could invade into the apical gingiva of periodontitis patients. The precise mechanism, however, remains to be elucidated. We assessed here the invasion mechanism of periodontal pathogens across the gingival epithelial barrier through two putative routes (transcellular and paracellular routes). After preculture of a gingival epithelial cell line (Ca9-22) on a filter insert of the double-chamber culture system, the suspensions of the laboratory strains of Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf), Treponema denticola (Td) and Aggregatibacter actinomycetemcomitans (Aa) were added to the upper chamber on the layered cells. At appropriate times of incubation, the translocated bacteria into the lower chamber were quantified by real-time PCR (q-PCR). Then, the disruption of cell-cell junctions in Ca9-22 was examined by the translocation of FITC-dextran. The bacteria which had invaded and persisted within Ca9-22 were also assessed by q-PCR. The results indicated that Pg invaded significantly at 6 hours of incubation through both transcellular and paracellular routes. Tf and Aa could also possess the invasive ability, although they utilized only the transcellular route. Consequently, many periodontal pathogens can invade significantly across the gingival epithelial barrier, whereas the translocation route may differ between the organisms.
To clarify the relationship between para-functional activity of the masticatory muscles and damage status of the implant superstructure, muscle activity in normal daily life was examined using a portable electromyograph (EMG).
Ten patients with repeat fractures of the superstructures caused by unconscious bruxism were enrolled. Those were classified into two groups depending on the damage: catastrophic failure (CF)and control (CO). The portable EMG recording device employed in this study has a one-channel EMG recording system and is composed of a remote control, a main unit, and an electrode unit. The portable EMG recording device was worn on the masseter muscle during the morning period (about 24 hours), and was able to detect bruxism without interfering in daily life. Obtained EMG data was transferred to the computer and analyzed using proprietary software. Based on our previous studies, thresholds were arranged to set the standard.
Bruxism-like events were observed in all subjects, and events beyond the threshold were also detected. The muscle mass activity per observed hour (parafunction) during awaking was higher than that during sleeping in all subjects. CF was significantly higher than CO. In contrast, no significant difference of functional activity was detected between those groups (P<0.05: MannWhitney U-test).
Patients with CF recorded greater muscle mass activity than the patients with CO. Those results suggested that the damage in the implant supported prostheses could be correlated to muscular mass activity.
We examined the accuracy, including trueness and precision, of the intraoral scanners comparing with laboratory desktop scanner to clarify the error level of intraoral scanners.
Measurements were performed using a computer numerical control coordinate measuring machine (CNCCMM) of the reference models as a control. Subsequently, intraoral scanners and a laboratory desktop scanner were used for measurements of the reference. Trueness and precision of distance were evaluated by image analyzing software.
The trueness measured by the True Definition Scanner(TDS) and Carestream3500 (CS) was bigger than that measured by TRIOS3(TR3) and KaVo(KA). With regard to reference model, there was a significant difference between the precision measured by CS and that measured by the other scanners. With regard to reference model, error of trueness measured by CS was significantly bigger, compared with the one measured by the other scanners. However, error range of intraoral scanners, except for CS, was considerably small.
The results of this study indicated that an optical impression method with an intraoral scanner could be applied to implant therapy for multiple teeth missing.
The purpose of our research is to identify causative metals by using Pertilce Induced X-ray Emission (PIXE) to directly analyze trace elements in the oral mucosal tissue affected by oral lichen planus (OLP). The subjects were 44 patients with OLP, and the patients were 16 males and 28 females, with a mean age of 62.9. The control was an elemental analysis by PIXE of the oral mucosa of 100 healthy persons.
Seventeen essential elements―Si, Cu, V, Cr, Mn, Fe, Co, Ni, Zn, Se, Mo, Sn, Ge, As, Br, Rb, and Pd ―were detected. Twelve contaminating elements were also detected―Al, Ti, Ga, Sr, Zr, Nb, Ag, Sb, Au, Hg, Pb, and Y. These findings were similar to those of mucosal tissue from healthy individuals. A comparison of detection rates and abundance showed that the mucosal tissue of the OLP group tended to have lower detection rates but a higher abundance of contaminating elements that should not exist in the body than the mucosal tissue of healthy individuals.
Additionally, the types of elements detected from serum, mucosal tissue, and saliva collected from the same individual were identical.
It is possible that contaminating elements accumulate in the mucosal tissue and are excreted along with the shedding of the mucosal epithelium.