An in vitro study of digital impressions and three-dimensional printed models of orbital defects using mobile devices and monoscopic photogrammetry.

PURPOSE: The purpose of this study was to perform an in vitro evaluation of digital impressions using a mobile device and monoscopic photogrammetry in cases of orbital defects with undercuts. METHODS: Three 10-mm-square cubes were attached to a diagnostic cast of a patient with a right orbital defect. Still images acquired with a mobile device were used to generate facial three-dimensional (3D) data. Two types of still images were used: one was a whole face image, and the other was a defect site-focused image. For comparison, an extraoral scanner was used to obtain facial 3D data. Five dental technicians fabricated 3D printed models using additive manufacturing and measured the distances between the measurement points using a digital caliper. The discrepancy between the distances measured on the diagnostic cast of the patient and the 3D printed model was calculated. Friedman test was used to analyze the discrepancy, and the Bonferroni test was used to verify the differences between the pairs. RESULTS: Statistical significance was found with respect to the type of 3D model fabrication method. CONCLUSION: Within the limitations of this in vitro study, the results suggested that the workflow can be applied to digital impressions of the maxillofacial region.

How school life with international students develops the intercultural competence of domestic dental students.

INTRODUCTION: Reflecting multicultural society, the diversity of the healthcare professional students' ethnicities and cultures is promoted around the world. However, most of the healthcare professional education in Japan had been targeted mainly at students who follow the Japanese language and culture. The aim of this study is to clarify what Japanese dental students have culturally experienced and how they developed intercultural competence during their school life with international dental students in Japan. MATERIALS AND METHODS: We conducted semi-structured interviews with 18 of the sixth-grade students in standard Japanese undergraduate dental programmes who shared required classes in Japan with non-Japanese-speaking international dental students in preclinical programmes. Based on the qualitative analysis of the interviews, we administered a questionnaire survey to 82 dental trainees (the seventh grade) in clinical training programmes who just graduated from various Japanese dental schools. Then, the answers of the questionnaire were statically analysed. RESULTS: The interview identified a total of 37 constituent elements regarding "students' attitudes and experiences in school days" and "perceptions and motivations." Analysis of the questionnaire showed that the group experiencing a learning environment with international students had various communication with and respect for their various classmates and had the ambition to develop themselves. Especially, the participants who had international experiences both in and out of classrooms showed more active attitude on intercultural communication. CONCLUSIONS: Overall, for Japanese dental students, daily contact with international students gave direct and indirect cross-cultural experiences and recognitions. In particular, the Japanese students were stimulated active perceptions. The findings of this study can be used for future discussion about the cross-cultural education and collaboration of healthcare professionals not only within Japan but also around the world.

In Vivo Efficacy of Lacticaseibacillus rhamnosus L8020 in a Mouse Model of Oral Candidiasis.

Oral candidiasis presents with multiple clinical manifestations. Among known pathogenic Candida species, Candida albicans is the most virulent and acts as the main causative fungus of oral candidiasis. Novel treatment modalities are needed because of emergent drug resistance and frequent candidiasis recurrence. Here, we evaluated the ability of Lacticaseibacillus rhamnosus L8020, isolated from healthy and caries-free volunteers, to prevent against the onset of oral candidiasis in a mouse model. Mice were infected with C. albicans, in the presence or absence of L. rhamnosus L8020. The mice were treated with antibiotics and corticosteroid to disrupt the oral microbiota and induce immunosuppression. We demonstrated that oral consumption of L. rhamnosus L8020 by C. albicans-infected mice abolished the pseudomembranous region of the mouse tongue; it also suppressed changes in the expression levels of pattern recognition receptor and chemokine genes. Our results suggest that L. rhamnosus L8020 has protective or therapeutic potential against oral candidiasis, which supports the potential use of this probiotic strain for oral health management.

Comprehensive analysis of transcriptional profiles in oral epithelial-like cells stimulated with oral probiotic Lactobacillus spp.

OBJECTIVE: The mechanisms of action of probiotics can vary among species and among strains of a single species; thus, they can affect host cells in a complex manner. In the present study, Lactobacillus spp. were evaluated for their ability to adhere to gingival epithelial-like cells. Comprehensive analyses of transcriptional profiles of mouse gingival epithelial GE1 cells treated with L. rhamnosus L8020 were performed to assess the putative in vivo probiotic potential of this strain. METHODS: Five Lactobacillus spp., isolated from the oral cavity, traditional Bulgarian yoghurt, and the feces of a healthy human, were each co-cultured with GE1 cells. Adhesion assays with serial dilution plating and DNA microarray analysis were performed to identify differentially expressed genes (DEGs) in GE1 cells grown in co-culture with L. rhamnosus L8020. RESULTS: The oral isolates L. rhamnosus L8020, L. casei YU3, and L. paracasei YU4 demonstrated significantly greater adhesion compared with the non-oral isolates. In total, 536 genes in GE1 cells exhibited more than twofold upregulation or downregulation, compared with the 0 h timepoint, during co-culture with L. rhamnosus L8020. Gene ontology enrichment analysis revealed that DEGs were differentially enriched in a time-dependent manner. Early responses involved widespread changes in gene expression. CONCLUSIONS: This study reveals changes in expression of genes involved in the epithelial physical barrier and immune response in gingival epithelial-like cells co-cultured with L. rhamnosus L8020. Further investigations regarding the molecular mechanisms by which L. rhamnosus L8020 serves as a probiotic may provide evidence to support clinical use.

Accuracy of a three-dimensional dentition model digitized from an interocclusal record using a non-contact surface scanner.

OBJECTIVES: For orthodontic treatment, it is important to assess the dental morphology, as well as the position and inclination of teeth. The aim of this article was to develop an efficient and accurate method for the three-dimensional (3D) imaging of the maxillary and mandibular dental morphology by measuring interocclusal records using an optical scanner. MATERIALS AND METHODS: The occlusal and incisal morphology of participants was registered in the intercuspal position using a hydrophilic vinyl polysiloxane and digitized into 3D models using an optical scanner. Impressions were made of the maxilla and mandible in alginate materials in order to fabricate plaster models and created into 3D models using the optical scanner based on the principal triangulation method. The occlusal and incisal areas of the interocclusal records were retained. The buccal and lingual areas were added to these regions entirely by the 3D model of the plaster model. The accuracy of this method was evaluated for each tooth, with the dental cast 3D models used as controls. RESULTS: The 3D model created from the interocclusal record and the plaster model of the dental morphology was analysed in 3D software. The difference between the controls and the 3D models digitized from the interocclusal records was 0.068±0.048mm, demonstrating the accuracy of this method. LIMITATIONS: The presence of severe crowding may compromise the ability to separate each tooth and digitize the dental morphology. CONCLUSIONS: The digitization method in this study provides sufficient accuracy to visualize the dental morphology, as well as the position and inclination of these teeth.

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.

Degree of immobilization of synthetic RGDS(PO(3)H(2))PA peptides on titanium surfaces.

The purpose of this study was to characterize the chemical interaction between titanium surfaces and the peptide RGDS(PO(3)H(2))PA (P-RGD) synthesized from RGD peptide (RGD) and o-phospho-L-serine (P-Ser), and to determine the degree of peptide immobilization on the titanium surface. X-ray photoelectron spectroscopy showed that the adsorption amount of RGD was significantly smaller than those of P-Ser and P-RGD (p<0.05). Furthermore, although it appeared that P-RGD bonded to the surface, ultrasonic rinsing with water caused it to dissociate, releasing RGD and leaving only S(PO(3)H(2))PA bonded to the surface. These findings show that although it remains difficult to obtain a stable P-RGD layer, the phosphate functional group greatly improves immobilization of the molecule on titanium surfaces.

A proposed index for residual periodontal ligament support.

An index was developed to estimate the residual periodontal ligament support for individual teeth during treatment planning for partially edentulous patients. The Residual Periodontal Ligament Index (rPLI) was derived from a formula that calculates the remaining area of periodontal attachment and the Normal Periodontal Ligament Index (nPLI). To illustrate the applicability of the rPLI, the total nPLI scores of the remaining teeth corresponding to Eichner subclasses of partial edentulism were charted by assessing the average occlusal support numerically. The rPLI is proposed to be a possible suitable tool for epidemiologic research on the progression of tooth loss and the survival rate of prostheses.

Body weight and serum albumin change after prosthodontic treatment among institutionalized elderly in a long-term care geriatric hospital.

OBJECTIVES: An important purpose of denture treatment is the improvement of nutritional intake. This is especially important for the dependent elderly who have a high risk of protein-energy malnutrition. To evaluate the impact of denture treatment on such a population, we compared body weight as an indicator of nutritional status before and 6 months after prosthodontic treatment. METHODS: This study was conducted in a long-term care geriatric hospital in Hiroshima, Japan from October 2004 to September 2006. One hundred and four patients received complete or partial denture treatment in both jaws. Nineteen patients were lost to the study because of the development of severe physical conditions or death. Among the remaining 85 patients, 66 used their new prostheses and 19 did not. Body weight and serum albumin levels were examined at prosthesis insertion and 6 months after treatment. RESULTS: Six months after prosthodontic treatment body weight changes were significantly different between users and non-users regardless of denture type and, in addition, serum albumin level were significantly increased among individuals using partial denture in either or both jaws (P < 0.05). CONCLUSION: It can be concluded that prosthodontic treatment may improve the nutritional status of institutionalized elderly.

Chemical interaction between titanium implant surface and amino acids.

The purpose of this study was to investigate the chemical interaction between titanium implant surface and amino acids. Pure titanium disks were pretreated with 10 N HCl and ultrapure water at room temperature for 30 minutes each. Disks were then modified with one of the three amino acids--L-aspartic acid, L-serine, or L-threonine--at 37 degrees C for 12 hours. Modification with oxalic acid was used as a control. By means of X-ray photoelectron spectroscopy (XPS), amino acid powders and the modified surfaces without or with ultrasonic water rinsing were chemically analyzed. It was revealed that the N 1s peak which originated from amino acids was not or hardly detected in the wide scan spectra of amino acid-modified surfaces. Moreover, the COO- peak which originated from oxalic acid could hardly be detected in the narrow scan spectrum of the C is region of oxalic acid-modified surface with ultrasonic water rinsing. Based on the results of this study, it was concluded that amino acids could not chemically bond to the titanium surface.

Influence of mental status on removable prosthesis compliance in institutionalized elderly persons.

PURPOSE: It is well-recognized that many institutionalized elderly persons with dementia do not wear dentures. The objective of this study was to evaluate the current status of denture use among elderly patients with dementia, in association with degree of mental impairment, to provide information relating to a decision-making process for optimal denture treatment. MATERIALS AND METHODS: From August 2001 to December 2002, 101 hospitalized elderly persons in a geriatric hospital dental clinic received removable denture treatment by two certified prosthodontists. Prior to denture treatment, patient mental status was evaluated using the Mini Mental Status Examination (MMSE). Basic activities of daily living, including mobility, feeding, toilet use, dressing, and bathing, were also evaluated. Denture acceptance was determined 6 months after denture delivery. RESULTS: Eight patients were excluded; 73 patients had accepted their dentures and 20 had not 6 months after denture delivery. The mean MMSE score for patients who did not accept denture delivery (11.7+/-7.0) was significantly lower than that of those who did accept and wear their dentures (16.0+/-6.8). CONCLUSION: The cognitive status of institutionalized elderly persons with dementia should be a criterion for clinical decision making relating to denture treatment.