Toshinobu Takemoto

Differential Effects of Various Growth Factors and Cytokines on the Syntheses of DNA, Type I Collagen, Laminin, Fibronectin, Osteonectin/Secreted Protein, Acidic and Rich in Cysteine (SPARC), and Alkaline Phosphatase by Human Pulp Cells in Culture

The purpose of this study is to differentiate roles of several growth factors and cytokines in proliferation and differentiation of pulp cells during development and repair. In human pulp cell cultures, laminin and type I collagen levels per cell remained almost constant during the whole culture period (22 days). On the other hand, secreted protein, acidic and rich in cysteine (SPARC/osteonectin) and alkaline phosphatase (ALPase) levels markedly increased after the cultures reached confluence. Laminin and type I collagen, as well as fibronectin, stimulated the spreading of pulp cells within 1 h. Adding transforming growth factor‐β (TGF‐β) decreased laminin and ALPase levels, whereas it increased SPARC and fibronectin levels 3‐ to 10‐fold. Western and Northern blots showed that TGF‐β enhanced SPARC synthesis at the protein and mRNA levels. Basic fibroblast growth factor (bFGF) decreased type I collagen, laminin, SPARC, and ALPase levels without changing the fibronectin level. Platelet‐derived growth factor (PDGF) selectively decreased laminin, SPARC, and ALPase levels. Epidermal growth factor (EGF) also decreased SPARC and ALPase levels. Tumor necrosis factor‐α (TNF‐α) and interleukin‐1β (IL‐1β) decreased type I collagen and laminin levels, and abolished SPARC and ALPase syntheses. Of these peptides, bFGF and PDGF showed the greatest stimulation of [3H]thymidine incorporation into DNA. TGF‐β, EGF, and TNF‐α had less effect on DNA synthesis, whereas IL‐1β inhibited DNA synthesis. These findings demonstrated that TGF‐β, bFGF, EGF, PDGF, TNF‐α, and IL‐1β have characteristically different patterns of actions on DNA, laminin, type I collagen, fibronectin, ALPase, and SPARC syntheses by pulp cells. J. Cell. Physiol. 174:194–205, 1998.

Bovine milk fermented with Lactobacillus rhamnosus L8020 decreases the oral carriage of mutans streptococci and the burden of periodontal pathogens

AIM   The aim of this study was to find the oral isolate of lactobacilli, which has the potential to inhibit either periodontal, cariogenic, or fungal pathogens in vitro, and to examine the effects of bovine milk fermented with the isolate on the oral carriage of cariogenic and periodontal pathogens. METHODS   The inhibitory effects of the supernatant of Man-Rogosa-Sharpe broth, in which each of 42 oral isolates of lactobacilli grown, was examined. One isolate, Lactobacillus rhamnosus L8020, that showed the potential to inhibit either periodontal, cariogenic, or fungal pathogens in vitro, was used to examine the effects of fermented milk on the oral carriage of cariogenic and periodontal pathogens, which was examined by a placebo-controlled and cohort trial using 50 participants. RESULTS   Edible yogurt containing Lactobacillus rhamnosus L8020 significantly reduced the oral carriage of mutans streptococci (P < 0.01) and four periodontal pathogens examined: Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, and Fusobacterium spp. (P < 0.01), but the phenomenon were not observed with the placebo yogurt (P > 0.05). CONCLUSION   These results suggest that yogurt with Lactobacillus rhamnosus L8020 could reduce the risk of dental caries and periodontal disease.

Chewing Gum Containing Citric Acid Reduces the Burden of Periodontal Pathogens

Objective: In a preliminary study, we noted that citric acid has the potency to induce human beta defensins (hBD-2) in salivary secretions. As hBDs are thought to ameliorate periodontal disease by suppressing key periodontal pathogens we developed a citric acid-containing chewing gum (CA-gum) to test this hypothesis. Here we report, the effect of CA-gum on three major periodontal pathogens Prevotella intermedia (Pi), Tannerella forsythia (Tf), Treponema denti- cola (Td) and Fusobacterium species (Fb). Methods: A randomized, double-blind, placebo-controlled trial with 61 individuals, was conducted over 14 days. Each subject was allowed to chew CA-gum (31 subjects) or placebo gum (30 subjects) at irregular intervals, but was instructed to eat at least three pieces of gum a day. None had active caries, symptoms of gingivitis or periodontal disease, smoking history, or concurrent medication. To determine the levels of oral carriage of the putative pathogens, saliva was collected from each subject by paraffin chewing in a standard manner and, the number of total cultivative microorganisms (CFUs) determined. Five key periodontal pathogens, Pg, Pi, Tf, Td and Fb present in saliva were determined quantitatively using real-time polymerase chain reaction (PCR) (BML Inc., Saitama, JAPAN). Results: Compared with the placebo chewing gum group the CA-gum group had significantly lower levels of Prevotella intermedia, Tannerella forsythia, and Fusobacterium spp. in their saliva. (Wilcoxon t-test; p 0.05).

Cellular immuno-competence of infected root canal contents in pathogenesis of periapical lesions

The soluble fractions of infected root canal contents (IRCC) were collected from about 300 human extracted teeth and examined for the presence of mononuclear cell (MNC) chemotaxis and cellular immunocompetence. IRCC showed remarkable chemotactic activity for polymorphonuclear leukocytes but a weak activity for MNC. However, generation of intrinsic MNC chemotaxis and induction of cellular immunity were confirmed in rats given repeated injections of IRCC.

Dental hygienists’ perceptions of professionalism are multidimensional and context-dependent: a qualitative study in Japan

BackgroundDue to the declining birth rate and aging of Japanese society, the roles and responsibilities of dental hygienists are continuously expanding. Medical professionalism needs to be pursued continuously throughout one’s career in order to improve dental care and treatment. Although conceptualising professionalism is essential to the education of health professionals, professionalism in the field of dental hygiene has not been defined or adequately examined in Japan. The purposes of this study are to investigate dental hygienists’ perceptions of the constituent elements of professionalism and the factors affecting their perceptions.MethodsSemi-structured interviews were conducted with 18 dental hygienists in Japan. Drawing on the conceptualisation of professionalism in medicine described by Van de Camp et al., the transcribed data were thematically analysed.ResultsThe dental hygienists in this study perceived 70 constituent elements that were categorised into eight core competencies related to professionalism. These competencies were further classified into three main themes: intrapersonal, interpersonal, and public professionalism. There were three sociohistorical factors that affected their perceptions of the constituent elements, namely academic background (university or technical school), the contexts of any previously provided dental care (university hospital or dental clinic), and their social interactions with their colleagues during their engagement in dental practice (dental team or interprofessional team). Moreover, according to their sociohistorical backgrounds, the dental hygienists saw themselves variously as scholars (university graduates), facilitators (university hospital), skillful artisans (dental clinic), or collaborators (interprofessional team).ConclusionsDental hygienists’ perceptions of professionalism are multidimensional and context-dependent, so culture- and professional-specific elements need to be included in educational curricula and continuing professional development programmes. In particular, the conceptualisation of professionalism in the field of dental hygiene as described in this study can be a springboard for enhancing undergraduate education and clinical training.

Changes in bacterial number at different sites of oral cavity during perioperative oral care management in gastrointestinal cancer patients: preliminary study

Abstract Objective The objective of this study was to clarify differences in bacterial accumulation between gastrointestinal cancer patients who underwent severely invasive surgery and those who underwent minimally invasive surgery. Material and Methods We performed a preliminary investigation of gastrointestinal cancer patients who were treated at the Department of Surgery, Takarazuka Municipal Hospital, from 2015 to 2017 (n=71; 42 laparoscopic surgery, 29 open surgery) to determine changes in bacterial numbers at different sites of the oral cavity (tongue dorsum, gingiva of upper anterior teeth, palatoglossal arch), as well as mouth dryness and tongue coating indices. Specifically, patients received professional tooth cleaning (PTC), scaling, tongue cleaning, and self-care instruction regarding tooth brushing from a dental hygienist a day before the operation. Professional oral health care was also performed by a dental hygienist two and seven days after surgery. Oral bacteria numbers were determined using a bacterial counter with a dielectrophoretic impedance measurement method. Results The number of bacteria at all three examined sites were significantly higher in the open surgery group when compared to the laparoscopic surgery group on the second postoperative day. Relevantly, bacterial count in samples from the gingiva of the upper anterior teeth remained greater seven days after the operation in patients who underwent open surgery. Furthermore, the dry mouth index level was higher in the open surgery group when compared to the laparoscopic surgery group on postoperative days 2 and 7. Conclusions Even with regular oral health care, bacterial numbers remained high in the upper incisor tooth gingiva in gastrointestinal cancer patients who received open surgery. Additional procedures are likely needed to effectively reduce the number of bacteria in the gingival area associated with the upper anterior teeth.