Improvement in oral function not only improves swallowing function but also helps prevent lifestyle-related diseases, such as stroke and diabetes. Therefore, modern dental care needs to provide support for overall body management as well as oral health management. A significant correlation has been reported between oral function indicated by maximum lip pressure and maximum tongue pressure and motor function evaluated by grip strength and the Timed Up and Go (TUG) Test in older persons. However, the correlation between oral and motor function in young adults has not been clarified. This study aimed to investigate the correlation between oral and motor function in young adults, and to examine the effectiveness of oral health support for maintaining general health.

The participants were 24 female students enrolled at the Department of Dental Hygiene in Nippon Dental University College at Tokyo. We measured maximum tongue pressure to evaluate oral function. We also measured grip strength, TUG, and the 30-Second Chair Stand Test (CS-30) to evaluate motor function. Subsequently, we statistically investigated the correlation between oral and motor function.

We found a significant correlation between maximum tongue pressure and grip strength (r = 0.560 (p <0.001)). However, no significant correlation was found between maximum tongue pressure and TUG, or between maximum tongue pressure and CS-30.

Grip strength is considered to indicate the basic physical strength of the entire body. Therefore, our results indicate a correlation between oral function and general physical fitness. The findings suggest the need for dental hygienists to understand the correlation between oral function and general physical fitness and to support patients in the acquisition of exercise habits to maintain eating and swallowing functions throughout their life.

Periodontal disease is caused by bacterial infection of the oral cavity, and Porphyromonas gingivalis (P. gingivalis) is the main cause of chronic periodontitis. Regular toothbrushing and the routine use of antibacterial agents are common methods of plaque control. The use of so-called “probiotic” microorganisms to prevent infection in this context has recently attracted increased attention. The current study assessed the bactericidal activities of Lactobacillus salivarius, Lactobacillus acidophilus, and Lactobacillus casei—which are commonly used as probiotics—against P. gingivalis. Mixed cultures containing each Lactobacillus species and P. gingivalis in equal concentrations were generated, and the subsequent numbers of viable bacteria were measured. The odors of mixed cultures were also measured. Furthermore, the disc diffusion method was used to investigate P. gingivalis viability in the presence of solutions derived from Lactobacillus cultures in conjunction with the measurement of inhibitory zones. Bactericidal activity against P. gingivalis was observed in all mixed cultures. Odor was also reduced. Notably however, in disc diffusion antimicrobial tests using culture-derived solutions there were no significant differences in any inhibitory zones. Live lactic acid bacteria may exert bactericidal effects on P. gingivalis. In the present study, it was suggested new possibilities for the prevention of periodontal disease using probiotics, including Lactobacillus bacteria.

In recent years, dentists and dental hygienists have had increased opportunities to consult on occlusal conditions and oral habits at health checkups for young children. This study aimed to clarify the correlation between the oral habits of 3 to 5-year-old children, who are still developing oral habits, and the personal oral hygiene practices of their parents. The obtained results were expected to contribute to dental health instruction for reducing the incidence of poor oral habits and increasing parents’ interest in dental care.

The questionnaire survey was conducted with parents of 5 to 6-year-old children participating in the “Teeth and Oral Health Week Project” held in the Hadano and Isehara Districts of Kanagawa Prefecture and parents of 3 to 6-year-old children attending K nursery school in Tokyo.

The most common oral habit of children was “finger sucking” at 29.7%, whereas “nothing in particular” accounted for 34.9%. Less than half of the children had no oral habits. Therefore, many children had some kind of oral habit. The results showed a significant correlation between the frequency of parents assisting with teeth brushing and children having or not having a finger-sucking habit.

Parents who practice good personal oral hygiene can reduce or eliminate the occurrence of poor oral habits in children. This finding suggests the importance of a thorough approach to providing instruction on personal oral hygiene practices to both children and parents.

The importance of extending healthy life expectancy has recently been greatly emphasized

and the public’s awareness of health is increasing. Acquiring regular eating habits is extremely important to maintain and improve health. Fermented foods have been considered good for health for a relatively long time. Lactic acid bacteria are typical bacteria found in fermented foods, and they are known to stimulate the immune system, regulate the intestines, and reduce cholesterol. In the field of dentistry, these bacteria have been reported to have an inhibitory effect on the development of caries and the growth of bacteria associated with periodontal disease, and oral care products containing various lactic acid bacteria to make use of these effects have been developed and marketed.

The aim of this study was to examine the growth inhibitory effect of commercially-available foods containing lactic acid bacteria on Streptococcus mutans (S.mutans) and Candida albicans (C.albicans) in oral care, and to evaluate the usefulness of these products as oral care tools. Specifically, three types of test foods were dissolved to prepare a test food solution, and we measured the proliferative ability of S.mutans and C.albicans in culture solutions with set amounts of test food added. The results demonstrated that there is a difference in their effect on the growth of S.mutans and C.albicans even in food marketed as containing lactic acid bacteria.

In future studies, it will be necessary to examine the duration of this effect and determine whether this effect holds in patients with oral disease, as well as to investigate whether there is a growth inhibitory effect on periodontal disease bacteria other than S. mutans and C. albicans.

The factors that trigger dental anxiety in patients include the sounds that characterize the environment of the dental clinic and the past treatment experiences of the patient. However, there is a dearth of literature on the strategies that dental hygienists can use to create an environment that prevents and reduces dental anxiety in patients. Therefore, the objective of the present study was to analyze the relationship between dental imagery and the environmental factors that trigger dental anxiety. A total of 114 participants, consisting of 58 first graders and 56 third graders from Nippon Dental University Niigata Junior College, responded to a survey questionnaire. We used chi-square test of independence to analyze individual differences in dental imagery and the factors that trigger dental anxiety in first graders and third graders. Environmental factors such as the “sound,” “smell,” and “dental equipment” of a dental clinic were reported as triggers of dental anxiety. Sound-related factors (e.g., the sound emitted by dental cutting devices during treatment) were frequently reported as triggers that evoke negative dental imagery and were described using words such as “pain” and “scary.” With regard to smell-related factors, aromatherapy was believed to alleviate negative dental imagery and dental anxiety among patients who experience anxiety in response to the smell of medicine. With regard to dental equipment-related factors, some participants reported that they became anxious when they viewed dental equipment, whereas others reported that they became anxious when they did not view them. These findings serve as an empirical base upon which appropriate corrective action that is aimed at mitigating dental anxiety in patients can be undertaken. Specifically, since the environment of the dental clinic has been found to be related to dental imagery, medical personnel can mitigate dental anxiety in patients by addressing environmental triggers.

Factors affecting plaque removal include toothbrush type, brushing method, and brushing pressure. In this study, the conditions of brushing method and pressure, which are different in different brush types, were changed, and a comparative examination was performed to assess plaque removal rate.

Toothbrushes were classified into 3 types: flat, dome, and mountain-cutting. Artificial plaque was applied on the mandibular left first molar. The plaque removal rate was determined using a cleaning tester after 5 strokes of brushing with bristles of 20 mm length and pressures of 150, 200, and 250 gf by scrubbing and bath methods.

In the scrubbing method, the mountain-cutting toothbrush had a higher plaque removal rate compared to the other toothbrush types, at brushing pressures of 150 and 200 gf. With the flat toothbrush, as the brushing pressure increased, the brush spread evenly, increasing the contact area with the tooth surface, thereby increasing the plaque removal rate. In the bath method, when the brushing pressure was set to 200 or 250 gf, the mountain-cutting toothbrush had the highest plaque removal rate. It is considered that at low brushing pressures, mountain-shaped bristles do not spread, decreasing the contact area between the brush and the tooth surface, resulting in a low plaque removal rate.

However, with mountain-cutting toothbrushes, as the plaque removal rate is greatly affected by the brushing pressure, detailed brushing pressure guidance is considered necessary when teaching patients the brushing method.