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Dive into the research topics where Takaharu Goto is active.

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Featured researches published by Takaharu Goto.


Journal of Dentistry | 2012

Biofilm formation of Candida albicans on implant overdenture materials and its removal

Jing Li; Katsuhiko Hirota; Takaharu Goto; Hiromichi Yumoto; Yoichiro Miyake; Tetsuo Ichikawa

OBJECTIVES The purposes of this study were to clarify the surface characteristics of various implant overdenture materials and the capabilities of Candida albicans adherence and biofilm formation on these surfaces, and to investigate the role of salivary mucin in biofilm formation. METHODS Seven commonly used implant and restorative materials were assessed. The surface roughness averages of all materials were limited to 0.07-0.10 μm. Contact angles and salivary mucin absorption were measured. After 90-min initial adhesion and 2-day biofilm formation, the amounts of C. albicans were determined by counting colony-forming units and the morphological characteristics were observed by scanning electron microscopy (SEM). The effects of saliva coating and the influences of material surface property on initial adhesion, biofilm formation and its removability were analysed by univariate two-way analysis of variance and multiple linear regression analysis. RESULTS Surface contact angle of materials, the index of hydrophobicity, was found to be correlated positively with initial adhesion and biofilm formation of C. albicans. A negative correlation between mucin absorption and removability of Candida biofilm indicates that mucin plays an important role in biofilm formation and its rigidity. SEM observation also revealed fewer Candida cells on saliva-coated Ti than on saliva-coated hydroxyapatite or acrylic resin. CONCLUSIONS The materials with different hydrophobic property and compositions display diverse manners of salivary mucin absorption, initial adhesion and biofilm formation. The hydrophobic materials encourage enhanced initial adhesion, subsequently resulting in the active biofilm formation. Mucin has decisive effects on Candida immobilization and biofilm development on the materials. CLINICAL SIGNIFICANCE Surface hydrophilic property and composition of materials and salivary proteins, especially mucin, affect the process of Candida biofilm formation and influence the amount and rigidity of formed biofilm. The present data may be applied as a reference for selecting materials in implant overdenture treatment from a microbiological point of view.


PLOS ONE | 2013

Oral factors affecting titanium elution and corrosion: an in vitro study using simulated body fluid.

Hideki Suito; Yuki Iwawaki; Takaharu Goto; Yoritoki Tomotake; Tetsuo Ichikawa

OBJECTIVES Ti, which is biocompatible and resistant to corrosion, is widely used for dental implants, particularly in patients allergic to other materials. However, numerous studies have reported on Ti allergy and the in vitro corrosion of Ti. This study investigated the conditions that promote the elution of Ti ions from Ti implants. METHODS Specimens of commercially pure Ti, pure nickel, a magnetic alloy, and a gold alloy were tested. Each specimen was immersed in a simulated body fluid (SBF) whose pH value was controlled (2.0, 3.0, 5.0, 7.4, and 9.0) using either hydrochloric or lactic acid. The parameters investigated were the following: duration of immersion, pH of the SBF, contact with a dissimilar metal, and mechanical stimulus. The amounts of Ti ions eluted were measured using a polarized Zeeman atomic absorption spectrophotometer. RESULTS Eluted Ti ions were detected after 24 h (pH of 2.0 and 3.0) and after 48 h (pH of 9.0). However, even after 4 weeks, eluted Ti ions were not detected in SBF solutions with pH values of 5.0 and 7.4. Ti elution was affected by immersion time, pH, acid type, mechanical stimulus, and contact with a dissimilar metal. Elution of Ti ions in a Candida albicans culture medium was observed after 72 h. SIGNIFICANCE Elution of Ti ions in the SBF was influenced by its pH and by crevice corrosion. The results of this study elucidate the conditions that lead to the elution of Ti ions in humans, which results in implant corrosion and Ti allergy.


Physiology & Behavior | 2015

Influence of food volume per mouthful on chewing and bolus properties.

Takaharu Goto; Atsuko Nakamich; Megumi Watanabe; Kan Nagao; Miwa Matsuyama; Tetsuo Ichikawa

BACKGROUND Behaviors relating to food intake, i.e., speed of chewing, number of chews, and bite size, are important for decreasing energy intake, which might reduce excess body weight and thus metabolic risk. This study aimed at investigating the influence of mouthful volume on the number of chews and food bolus properties in addition to clarifying appropriate eating behaviors related to mouthful volume. METHODS Fifteen young Japanese women volunteered to participate. The subjects were asked to spit the food bolus in a glass dish just before swallowing when eating 3 different foods: boiled rice, fish sausage, and peanuts. The 3 physical properties of solidity, adhesiveness, and cohesiveness were measured in the bolus, and the number of chews was noted. RESULTS The number of chews significantly increased with increasing mouthful volume with all 3 foods; conversely, the number of chews per unit of food weight (g) decreased significantly with boiled rice and fish sausage. Trends were observed for solidity and cohesiveness, which varied with increasing mouthful volumes. CONCLUSIONS Decreased mouthful volume resulted in a greater number of chews per weight of food and more appropriate bolus properties; therefore, a change in mouthful volume could be a useful behavior modification for regulation of energy intake.


Scientific Reports | 2016

Periodontal tactile input activates the prefrontal cortex

Nobuaki Higaki; Takaharu Goto; Tetsuo Ichikawa

The prefrontal cortex (PFC) plays a role in complex cognitive behavioural planning, decision-making, and social behaviours. However, the effects of sensory integration during motor tasks on PFC activation have not been studied to date. Therefore, we investigated the effect of peripheral sensory information and external information on PFC activation using functional near-infrared spectroscopy (fNIRS). Cerebral blood flow (CBF) was increased around bilateral Brodmann areas 46 and 10 during visual and auditory information integration during an occlusal force (biting) task. After local anesthesia, CBF values were significantly decreased, but occlusal force was similar. In conclusion, the effects of peripheral sensory information from the periodontal ligament and external information have minimal impacts on occlusal force maintenance but are important for PFC activation.


Journal of Prosthodontics | 2016

Part-Digitizing System of Impression and Interocclusal Record for Complete Denture Fabrication.

Takashi Matsuda; Takaharu Goto; Kazutomo Yagi; Toshiya Kashiwabara; Tetsuo Ichikawa

Few studies have reported the application of digital technology to removable dentures, particularly for the process of impression and interocclusal recording for complete denture fabrication. This article describes a part-digitizing system of impression and interocclusal records for complete denture fabrication. The denture foundation area in an edentulous mouth, including the border areas and residual ridge, is outlined by tracing the surfaces with a 3-D pen-type digitizer. Specialized trays for final impressions and interocclusal records were generated using computer-aided design and manufactured using the digital data. Final impression and interocclusal records were carried out using these specialized trays. The computer-aided method using preliminary digital impressions and specialized trays would be feasible for clinical use for complete denture fabrication.


PLOS ONE | 2013

Blue-Violet Laser Modification of Titania Treated Titanium: Antibacterial and Osteo-Inductive Effects

Takanori Kawano; Widyasri Prananingrum; Yuichi Ishida; Takaharu Goto; Yoshihito Naito; Megumi Watanabe; Yoritoki Tomotake; Tetsuo Ichikawa

Background Many studies on surface modifications of titanium have been performed in an attempt to accelerate osseointegration. Recently, anatase titanium dioxide has been found to act as a photocatalyst that expresses antibiotic properties and exhibits hydrophilicity after ultraviolet exposure. A blue-violet semiconductor laser (BV-LD) has been developed as near-ultraviolet light. The purpose of this study was to investigate the effects of exposure to this BV-LD on surface modifications of titanium with the goal of enhancing osteoconductive and antibacterial properties. Methods The surfaces of pure commercial titanium were polished with #800 waterproof polishing papers and were treated with anatase titania solution. Specimens were exposed using BV-LD (λ = 405 nm) or an ultraviolet light-emitting diode (UV-LED, λ = 365 nm) at 6 mW/cm2 for 3 h. The surface modification was evaluated physically and biologically using the following parameters or tests: surface roughness, surface temperature during exposure, X-ray diffraction (XRD) analysis, contact angle, methylene blue degradation tests, adherence of Porphyromonas gingivalis, osteoblast and fibroblast proliferation, and histological examination after implantation in rats. Results No significant changes were found in the surface roughness or XRD profiles after exposure. BV-LD exposure did not raise the surface temperature of titanium. The contact angle was significantly decreased, and methylene blue was significantly degraded. The number of attached P. gingivalis organisms was significantly reduced after BV-LD exposure compared to that in the no exposure group. New bone was observed around exposed specimens in the histological evaluation, and both the bone-to-specimen contact ratio and the new bone area increased significantly in exposed groups. Conclusions This study suggested that exposure of titanium to BV-LD can enhance the osteoconductivity of the titanium surface and induce antibacterial properties, similar to the properties observed following exposure to UV-LED.


Journal of Prosthodontic Research | 2017

Duplication of complete dentures using general-purpose handheld optical scanner and 3-dimensional printer: Introduction and clinical considerations.

Kosuke Kurahashi; Takashi Matsuda; Takaharu Goto; Yuichi Ishida; Teruaki Ito; Tetsuo Ichikawa

PURPOSE To introduce a new clinical procedure for fabricating duplicates of complete dentures by bite pressure impression using digital technology, and to discuss its clinical significance. METHODS The denture is placed on a rotary table and the 3-dimensional form of the denture is digitized using a general-purpose handheld optical scanner. The duplicate denture is made of polylactic acid by a 3-dimensional printer using the 3-dimensional data. CONCLUSION This procedure has the advantages of wasting less material, employing less human power, decreasing treatment time at the chair side, lowering the rates of contamination, and being readily fabricated at the time of the treatment visit.


Journal of Prosthodontics | 2015

Influence of Matrix Attachment Installation Load on Movement and Resultant Forces in Implant Overdentures

Takaharu Goto; Kan Nagao; Yuichi Ishida; Yoritoki Tomotake; Tetsuo Ichikawa

PURPOSE This in vitro study investigated the effect of attachment installation conditions on the load transfer and denture movements of implant overdentures, and aims to clarify the differences among the three types of attachments, namely ball, Locator, and magnet attachments. MATERIALS AND METHODS Three types of attachments, namely ball, Locator, and magnetic attachments were used. An acrylic resin mandibular edentulous model with two implants placed in the bilateral canine regions and removable overdenture were prepared. The two implants and bilateral molar ridges were connected to three-axis load-cell transducers, and a universal testing machine was used to apply a 50 N vertical force to each site of the occlusal table in the first molar region. The denture movement was measured using a G(2) motion sensor. Three installation conditions, namely, the application of 0, 50, and 100 N loads were used to install each attachment on the denture base. The load transfer and denture movement were then evaluated. RESULTS The resultant force decreased with increasing installation load for all attachments. In particular, the resultant force on implants on the loading side of the Locator attachment significantly decreased when the installation load was increased from 0 to 50 N, and that for magnetic attachment significantly decreased when the installation load was increased from 50 to 100 N. For the residual ridges on the loading side, the direction of the forces for all attachments changed to downward with increasing installation load. Furthermore, the yaw Euler angle increased with increasing installation load for the magnetic attachment. CONCLUSIONS Subject to the limitations of this study, the use of any installation load greater than 0 N is recommended for the installation of ball and Locator attachments on a denture base. Regarding magnetic attachments, our results also recommend installation on a denture base using any installation load greater than 0 N, and suggest that the resultant force acting on the implant can be decreased by increasing the installation load; however, a large installation load of 100 N should be avoided when installing the attachment on the denture base to avoid increasing the denture movement.


Research in Gerontological Nursing | 2017

Development of an Oral Assessment Sheet for Evaluating Older Adults in Nursing Homes

Shizuko Yanagisawa; Masanori Nakano; Takaharu Goto; Masami Yoshioka; Yasuhiko Shirayama

A new general use oral assessment sheet (OAS), comprising three items each in three categories (i.e., oral hygiene, biting and chewing, and oral function), was developed to improve the oral health of older adults requiring nursing care. Seventy-nine care workers used the assessment sheet to evaluate oral conditions in 188 institutionalized older adults. Forty-five care workers and three dental professionals then assessed oral conditions in 45 institutionalized older adults using the test-retest method before and after dental professional guidance. Cronbachs alpha of the OAS was 0.72, and 0.65, 0.57, and 0.82 for the three subcategories of oral hygiene, biting and chewing, and oral function, respectively. After dental professional intervention, absolute and relative agreement coefficients increased to more than 0.6 and 0.89, respectively. Reliability and validity of the OAS were verified, and difficulties in oral assessment experienced by care workers were identified. [Res Gerontol Nurs. 2017; 10(5):234-239.].


Journal of Texture Studies | 2017

Changes in food bolus texture during mastication

Sachie Wada; Takaharu Goto; Keiko Fujimoto; Megumi Watanabe; Kan Nagao; Atsuko Nakamichi; Tetsuo Ichikawa

The purpose of this study was to survey the changes that occur in bolus texture from intake to swallowing during the mastication process for four types of food materials and to identify how texture is related to the number of chews. We recruited 15 young Japanese participants for this study. The subjects were asked to spit the food bolus just before swallowing when eating four different foods: cracker, boiled rice, hard gelatine gel, and soft gelatine gel. Three physical properties (hardness, adhesiveness, and cohesiveness) were measured in the bolus after being chewed for 25, 50, 75, 100, and 125% of the normal number of chews. Occlusal force and pressure as well as stimulated whole saliva volume were also measured. Extensive variation in the number of chews existed between subjects, but minimal intra-subject variation was observed. Hardness was observed to decrease, whereas cohesiveness and adhesiveness increased in a chew-dependent manner for the cracker, soft gelatine gel, and hard gelatine gel, but not boiled rice. Bolus texture appears to be largely related to the number of chews. Hardness also tended to be influenced by occlusion. The adhesiveness and hardness of the boiled rice were also greatly influenced by saliva volume and occlusal force, respectively. Hardness is an important rheological factor in food bolus texture and likely plays a significant role in determining the appropriate number of chews. Adhesiveness and cohesiveness appear to be secondary factors in this process. PRACTICAL APPLICATIONS We propose a model of oral processing for application in determining the appropriate number of chews for an individual. Hardness appears to be an important rheological factor in food bolus texture, with adhesiveness and cohesiveness being secondary aspects. When food is hard or difficult to swallow, chewing behavior will likely be more influenced by the perception of bolus texture.

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Kan Nagao

University of Tokushima

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Yuki Iwawaki

University of Tokushima

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