The Effects of Ultraviolet Light-Emitting Diodes with Different Wavelengths on Periodontopathic Bacteria In Vitro.

Objective: The aim of this study was to examine effects of recently developed ultraviolet light-emitting diodes (UV LEDs) wavelengths on in vitro growth and gene expression of cultural periodontopathic bacteria, and on viability of experimental gingival fibroblasts. Materials and methods: Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, and Streptococcus oralis were irradiated by UV LEDs (265, 285, 310, 365, and 448 nm) at 600 mJ/cm2 and grown anaerobically in vitro. The colony forming units were counted after 1 week. Cell morphology was observed using a scanning electron microscope (SEM). Quantitative real-time polymerase chain reaction was performed to investigate gene expression changes by 310 nm irradiation. Viability of the irradiated human gingival fibroblasts was evaluated using WST-8 assay. Results: Both 265 and 285 nm resulted in the complete death of bacteria and fibroblasts, whereas 310 nm caused partial killing and suppression of bacterial growth and much less damage to the fibroblasts in vitro. Both 365 and 448 nm resulted in no significant change. SEM showed that P. gingivalis cells gradually degraded from day 2 or 3 and were severely destructed on day 5 for 265, 285, and 310 nm. The 310 nm irradiation transiently suppressed the transcripts of SOS response- and cell division-relative genes. Conclusions: Both 265 and 285 nm may induce powerful bactericidal effects and severe fibroblast phototoxicity, and 310 nm may induce partial killing or growth suppression of bacterial cells with much less fibroblast phototoxicity. UV lights may have potential for bacterial suppression, with situations dependent on wavelength, in periodontal and peri-implant therapy.

Evaluation of Root Canal Anatomy of Maxillary Premolars Using Swept-Source Optical Coherence Tomography in Comparison with Dental Operating Microscope and Cone Beam Computed Tomography.

OBJECTIVE: This study aimed to evaluate the ability of swept-source optical coherence tomography (OCT) to detect internal anatomy of maxillary premolars in comparison with dental operating microscope (DOM) and cone beam computed tomography (CBCT). BACKGROUND DATA: The ability of OCT to observe the pulp horn during cavity preparation and assess the remaining dentin thickness (RDT) has been demonstrated, whereas validation of OCT in comparison with other imaging techniques seems required. METHODS: Ten extracted human maxillary premolars were sectioned perpendicular to the tooth axis from the occlusal surface at approximately 2 mm increments. OCT and DOM were performed after each cut, and microfocus X-ray computed tomography (micro-CT; reference standard) and CBCT were conducted before sectioning and after the first and second cuts. Three examiners evaluated all images for presence of the pulp horn/pulp chamber, isthmus, lateral canals, and the number of root canals. RDT was determined from OCT, micro-CT, and CBCT images. Correlations were analyzed with Pearson's correlation coefficient. RESULTS: OCT had a sensitivity and specificity of 0.90 and 0.80 in detecting the pulp horn/pulp chamber and 0.84 and 0.71 in detecting the isthmus, respectively. The three techniques showed strong correlations in detecting the number of root canals compared with micro-CT. OCT and DOM did not detect lateral canals. For RDT values, strong correlations were observed between micro-CT and CBCT, micro-CT and OCT, and CBCT and OCT (p < 0.01 for all). CONCLUSIONS: Under the present experimental condition, OCT accurately measured RDT and detected internal tooth anatomy such as the pulp horn, isthmus, and root canals.

Evaluation of bulk-fill systems: microtensile bond strength and non-destructive imaging of marginal adaptation

Abstract The objective of this study was to investigate microtensile bond strength (MTBS) and interfacial adaptation (IA) of bulk-fill restorative systems bonded to dentin in Class-I-preparations. Box-shaped preparations (4-mm-long, 3-mm-wide, 2-mm-high) made in extracted molars, and Teflon matrix with the same dimensions positioned over the occlusal surface were restored, providing a total of 4-mm composite depth using three bulk-fill restorative systems: Tetric EvoCeram Bulk Fill with Tetric N-Bond (TEC/TNB), SureFil SDR Flow with XP Bond (SDR/XPB) and Filtek Bulk Fill Flowable Restorative with Scotchbond Universal (FBF/SBU); or incrementally restored with a conventional restorative system: Herculite Classic with OptiBond FL (HER/OBF). The specimens were sectioned into beams and the MTBS measured after 24-hours or one-year storage. For evaluation of IA, round-tapered tooth preparations (3-mm-diameter, 1.5-mm-deep) were made, restored with each material and their cross-sectional images were obtained after 24-hours using optical coherence tomography (OCT). The gap percentage for each restoration system was calculated using image analysis software. MTBS for both storage periods: HER/OBF=TEC/TNB=SDR/XPB>FBF/SBU (ANOVA, Tukey's post-hoc, P<0.05) differed significantly among groups, which values were significantly reduced after one-year. SDR/XPB showed comparatively lesser gap formation at the tooth-interface after 24 hours (ANOVA, Dunnett's T3 post-hoc, P<0.05). For deeper restorations, bond strength of TEC/TNB and SDR/XPB can be equal to that of HER/OBF after 24-hours and one-year; however, in a shallower preparation, SDR/XPB showed greater initial interfacial adaptation.

Bactericidal effects of 310 nm ultraviolet light-emitting diode irradiation on oral bacteria.

BACKGROUND: Ultraviolet (UV) light is used for phototherapy in dermatology, and UVB light (around 310 nm) is effective for treatment of psoriasis and atopic dermatitis. In addition, it is known that UVC light (around 265 nm) has a bactericidal effect, but little is known about the bactericidal effect of UVB light. In this study, we examined the bactericidal effects of UVB-light emitting diode (LED) irradiation on oral bacteria to explore the possibility of using a 310 nm UVB-LED irradiation device for treatment of oral infectious diseases. METHODS: We prepared a UVB (310 nm) LED device for intraoral use to examine bactericidal effects on Streptococcus mutans, Streptococcus sauguinis, Porphyromonas gingivalis, and Fusobacterium nucleatum and also to examine the cytotoxicity to a human oral epithelial cell line (Ca9-22). We also examined the production of nitric oxide and hydrogen peroxide from Ca9-22 cells after irradiation with UVB-LED light. RESULTS: Irradiation with the 310 nm UVB-LED at 105 mJ/cm2 showed 30-50% bactericidal activity to oral bacteria, though 17.1 mJ/cm2 irradiation with the 265 nm UVC-LED completely killed the bacteria. Ca9-22 cells were strongly injured by irradiation with the 265 nm UVC-LED but were not harmed by irradiation with the 310 nm UVB-LED. Nitric oxide and hydrogen peroxide were produced by Ca9-22 cells with irradiation using the 310 nm UVB-LED. P. gingivalis was killed by applying small amounts of those reactive oxygen species (ROS) in culture, but other bacteria showed low sensitivity to the ROS. CONCLUSIONS: Narrowband UVB-LED irradiation exhibited a weak bactericidal effect on oral bacteria but showed low toxicity to gingival epithelial cells. Its irradiation also induces the production of ROS from oral epithelial cells and may enhance bactericidal activity to specific periodontopathic bacteria. It may be useful as a new adjunctive therapy for periodontitis.

Change in Food Intake Status of Terminally Ill Cancer Patients during Last Two Weeks of Life: A Continuous Observation.

BACKGROUND: The oral food intake of terminally ill cancer patients is known to gradually decrease, but there are few reports about how oral intake changes around the terminal stage. It is important to clarify changes in oral food intake, as such changes affect the support and care of terminally ill cancer patients. OBJECTIVE: We aimed to clarify changes in oral food intake in terminally ill cancer patients during the last 2 weeks before death. METHODS: This retrospective cohort study was conducted at a designated cancer center hospital in Japan from January 2013 to June 2013. The subjects were recognized as clinically terminally ill cancer patients who were hospitalized for ≥14 days, and who had death as their reason for hospital discharge. One researcher investigated basic patient information and the food intake status of the subjects using their medical records. The basic information investigated was gender, age, type of cancer, and the presence of gastrointestinal obstruction 14 days prior to death. The Food Intake LEVEL Scale (FILS) was prospectively recorded. RESULTS: After applying the exclusion criteria, 108 subjects were finally included in the analysis (59 males aged 70.3 ± 13.3 years; 49 females aged 70.3 ± 14.5 years). The FILS gradually declined, and half of the subjects were unable to take food orally 6 days before death. In 81 subjects, after excluding subjects with gastrointestinal obstruction, the FILS gradually declined, and half of the subjects were unable to take food orally 4 days prior to death. CONCLUSIONS: Many terminally ill cancer patients can take food orally up to a few days prior to their death. Therefore, various specialists should support the oral intake of terminally ill cancer patients until immediately before their death.

Application of optical coherence tomography to identify pulp exposure during access cavity preparation using an Er:YAG laser.

OBJECTIVE: The study aimed to evaluate the ability of optical coherence tomography (OCT) to guide and identify pulp exposure using an erbium: yttrium-aluminum-garnet (Er:YAG) laser. BACKGROUND DATA: The Er:YAG laser has been proven to be effective in ablating dental hard tissue and offers advantages, as there is none of the vibration and noise you get with conventional methods, but it has limitations in relation to the tactile feedback that would aid in identification of entry into the pulp chamber. Based on depth-resolved optical reflectivity, OCT technology has been developed to provide high-resolution, cross-sectional images of the internal structure of biological tissues. MATERIALS AND METHODS: The pulp chambers of 20 human mandibular incisors were examined, and the average thickness of hard tissue covering the pulp chamber was assessed using micro-computed tomography (micro-CT) images. An Er:YAG laser was used to gradually penetrate the hard tissue over the pulp chamber under microscopic guidance. The preparation was constantly imaged using a swept-source OCT at 10 sec intervals until a pulp chamber exposure was identified using the technology. The pulp exposure was re-examined under the microscope and compared with micro-CT images for verification. RESULTS: The pulp exposures of 20 incisors were all verified microscopically and with micro-CT images. The thickness of hard tissue penetrated by the laser ranged from 0.44 to 1.69 mm. CONCLUSIONS: Swept-source OCT is a useful tool for identifying pulp exposure during access opening with the Er: YAG laser.

Thermal taste and anti-aspiration drugs: a novel drug discovery against pneumonia.

Despite the development of strong antibiotics, the pneumonia death is increasing all over the world in these decades. Among the people who died of pneumonia, the majority were 65 years old or over. Although pneumonia is recently categorized into several entities, aspiration pneumonia includes all entities. Therefore, targeting dysphagia and aspiration to treat pneumonia is a promising strategy and anti-aspiration drugs will be a part of pneumonia treatment. The swallowing reflex in elderly people was temperature-sensitive and the improvement of swallowing reflex by temperature stimuli could be mediated by the thermosensing TRP channels at pharynx. The administration of capsaicin as an agonist stimulus of TRPV1, a warm temperature receptor, decreased the delay in swallowing reflex. Red wine polyphenols improved swallowing reflex by enhancing TRPV1 response. Food with menthol, agonist of TRPM8 which is a cold temperature receptor, also decreased the delay in swallowing reflex. Olfactory stimulation such as black pepper was useful to improve the swallowing reflex for people with low ADL levels or with decreased consciousness. Thus, recent advancement of geriatrics found several anti-aspiration drugs such as thermosensing TRP channel agonists, black pepper odor, amantadine, cilostazol, theophylline and angiotensin- converting enzymes inhibitors. Thermosensing TRP channel agonists include capsaicin, capsiate, menthol, and red wine polyphenols. Controls of swallowing are mediated by various stages of neural system from peripheral sensory nerves to the entire cerebral cortex. Each anti-aspiration drug acts on various sites of neural axis of swallowing reflex. The combination of various anti-aspiration drugs may improve dysphagia and prevent aspiration pneumonia.

Location dependency of the spatial resolution of cone beam computed tomography for dental use.

OBJECTIVE: This study evaluates the spatial resolution of cone beam computed tomography for dental use (CBCT) via modulation transfer function (MTF) analyses. STUDY DESIGN: Two models of CBCT system, 3DX FPD8 and FineCube v.12, were used. MTF analysis was applied to each CBCT system using a thin tungsten wire technique. RESULTS: The MTF curves in the radial direction on the XY-plane were concordant regardless of position, whereas the curves in the azimuthal direction tended to decrease as the distance from the rotation center increased. In the Z-axis direction, the MTF curve of the medial level of the field of view was superior to that of any other level. CONCLUSION: The spatial resolution of CBCT systems depends on the location within the field of view. Because the spatial resolution was the highest in the medial level and rotation center position, an object should be placed at this position during a CBCT examination.

Detection of root surface fractures with swept-source optical coherence tomography (SS-OCT).

OBJECTIVE: The purpose of this study was to compare optical coherence tomography (OCT) with the existing technologies, to assess its accuracy and utility in detecting vertical root fractures of extracted human teeth. BACKGROUND DATA: The detection of root fractures in teeth that have undergone root canal treatment is challenging because of the great difficulty in differentiating these fractures from morphologic or radiographic anomalies. OCT methods are based on depth-resolved optical reflectivity and have been developed to reduce the invasiveness and radiation exposure inherent to other techniques. METHODS: Twelve extracted human mandibular teeth (totaling 25 roots) that were free of caries, calculus, and root treatment were used, and assessed by microfocus computed tomography, the current gold standard for fracture detection. The ability of appropriately trained observers to detect root fractures using visual, microscopic, and swept-source OCT (SS-OCT) techniques were compared. micro-CT and SS-OCT produce three-dimensional images of the tooth from which to diagnose fractures, but CT scanning involves radiation exposure that is not required in SS-OCT. RESULTS: Seventeen of the 25 roots were found to have fractures by microfocus CT. These findings were replicated by SS-OCT, which revealed fractures exhibiting identical origin, size, and angulation within the root. We found that SS-OCT gave results compatible to the gold standard technique, and that SS-OCT and microscopy were more effective for identifying root fractures than was visual observation alone. CONCLUSIONS: SS-OCT may represent a novel, noninvasive, noncontact and nonexposure alternative to the conventional methods used for assessing root fractures in teeth.

Non-Hodgkin lymphoma involving the mandible: imaging findings.

OBJECTIVE: The aim of this study was to investigate the imaging findings of non-Hodgkin lymphoma (NHL) involving the mandible. STUDY DESIGN: The imaging studies of 4 patients with NHL involving the mandible were retrospectively reviewed. Panoramic and computerized tomographic (CT) images were available for all patients. Magnetic resonance imaging (MRI) was available for 3 patients. RESULTS: On panoramic images, an apparent radiolucent lesion was found in only 2 of 4 cases. However, in all cases careful observation demonstrated imaging findings suggesting malignancy. On CT and MRI, tumor replaced the bone marrow in all cases and spread to the surrounding soft tissue in 3 cases. Cortical bone destruction tended to be mild for the extent of tumor involvement. CONCLUSIONS: NHL involving the mandible tended to show slight or mild cortical bone destruction relative to the extent of the tumor involvement. Careful observation was considered to be necessary when interpreting conventional images, because they might not clearly demonstrate bone destruction.

Swept-source optical coherence tomography as a new tool to evaluate defects of resin-based composite restorations.

OBJECTIVES: Current diagnostic imaging modalities for resin-based composites (RBC) do not possess sufficient resolution and cross-sectional tomographic imaging to detect defects of RBC restorations in real-time. The purpose of this in vivo study was to investigate swept-source optical coherence tomography (SS-OCT) as a new tool to evaluate defects of RBC restorations. METHODS: We evaluated for the failure of RBC restorations in 52 patients (11 male, 41 female) at the Division of Oral and Dental Surgery, National Centre for Geriatrics and Gerontology, Japan. SS-OCT images of the 132 RBC restorations were obtained in order to investigate their marginal adaptation, porosity and internal integrity. RESULTS: Rates of defective restorations in terms of marginal adaptation, large porosity and gap formation were 65.2 percent, 27.3 percent, and 15.2 percent, respectively. Only 18.9 percent of the RBC restorations had no defects. CONCLUSIONS: SS-OCT has the potential to provide higher-resolution information related to the structure of RBC restorations currently unavailable with any diagnostic or imaging method.

In vivo imaging of human labial glands using advanced optical coherence tomography.

OBJECTIVE: Optical coherence tomography (OCT) has emerged as a high-resolution noninvasive clinical imaging application. The purpose of this study was to show OCT images of human labial glands obtained using a swept-source (SS) OCT system. STUDY DESIGN: Labial gland OCT imaging was carried out using our new SS-OCT system for 5 healthy volunteers using a hand-held in vivo OCT scanning probe. The labial tissue was scanned in a superior to inferior direction in 2 and 3 dimensions. RESULTS: The resulting 2- and 3-dimensional ultrahigh-resolution images of in vivo OCT human labial minor salivary glands revealed the epithelium, connective tissue, lobes, and duct. OCT was capable of providing simultaneous and noninvasive structural information with high resolution. CONCLUSION: This clinical imaging modality promises to have clinical impact in the diagnosis of such conditions as Sjögren syndrome and xerostomia.

Osteonecrosis associated with short-term oral administration of bisphosphonate.

Orally administered bisphosphonates are generally considered a first-line medication for treatment of osteoporosis. As a side effect of bisphosphonates, osteonecrosis of the jaws (ONJ) has been reported worldwide. Most reports of osteonecrosis are attributed to the use of bisphosphonates administered intravenously for the treatment of bone disorders such as multiple myeloma. However, osteonecrosis has also been diagnosed in patients receiving oral bisphosphonates. The management of a patient with spontaneous removable partial denture prosthesis-related ONJ associated with short-term oral administration of bisphosphonate is described.

Evaluation of oral vascular anomalies using optical coherence tomography.

Optical coherence tomography (OCT) is a new method of biomedical imaging that can generate high-resolution, cross-sectional images of microstructures. The purpose of this study was to present the first OCT images of oral vascular anomalies using a new advanced OCT scanner that we have developed, and to discuss the application of our system for oral soft tissues. Knowledge of the size and area of the vascular structures can be useful for the diagnosis and choice of the best treatment. Before excision, oral vascular malformations were assessed by OCT in vivo. Histopathological sections were taken and compared with the OCT images to make clinicopathological correlations. OCT provided clear images of all the vascular lesions examined. Oval to roundish, signal-poor areas sharply demarcated by a surrounding signal-rich layer correlated well with the histopathological diagnosis. OCT images provide information about subsurface structure non-invasively that is otherwise obtainable only by examination of a biopsy specimen. The analysis of oral vascular lesions by OCT provides new insights into non-invasive diagnosis and can be helpful in the selection of the most appropriate treatment.