Effect of CD146+ SHED on bone regeneration in a mouse calvaria defect model.

OBJECTIVE: Stem cells from human exfoliated deciduous teeth (SHED) have bone regeneration ability and potential therapeutic applications. CD146, a cell adhesion protein expressed by vascular endothelial cells, is involved in osteoblastic differentiation of stem cells. The effect of CD146 on SHED-mediated bone regeneration in vivo remains unknown. We aimed to establish efficient conditions for SHED transplantation. MATERIALS AND METHODS: SHED were isolated from the pulp of an extracted deciduous tooth and cultured; CD146-positive (CD146+ ) and CD146-negative (CD146- ) populations were sorted. Heterogeneous populations of SHED and CD146+ and CD146- cells were transplanted into bone defects generated in the skulls of immunodeficient mice. Micro-computed tomography was performed immediately and 4 and 8 weeks later. Histological and immunohistochemical assessments were performed 8 weeks later. RESULTS: Bone regeneration was observed upon transplantation with CD146+ and heterogeneous populations of SHED, with significantly higher bone regeneration observed with CD146+ cells. Bone regeneration was higher in the CD146- group than in the control group, but significantly lower than that in the other transplant groups at 4 and 8 weeks. Histological and immunohistochemical assessments revealed that CD146+ cells promoted bone regeneration and angiogenesis. CONCLUSION: Transplantation of CD146+ SHED into bone defects may be useful for bone regeneration.

Bone Differentiation Ability of CD146-Positive Stem Cells from Human Exfoliated Deciduous Teeth.

Regenerative therapy for tissues by mesenchymal stem cell (MSCs) transplantation has received much attention. The cluster of differentiation (CD)146 marker, a surface-antigen of stem cells, is crucial for angiogenic and osseous differentiation abilities. Bone regeneration is accelerated by the transplantation of CD146-positive deciduous dental pulp-derived mesenchymal stem cells contained in stem cells from human exfoliated deciduous teeth (SHED) into a living donor. However, the role of CD146 in SHED remains unclear. This study aimed to compare the effects of CD146 on cell proliferative and substrate metabolic abilities in a population of SHED. SHED was isolated from deciduous teeth, and flow cytometry was used to analyze the expression of MSCs markers. Cell sorting was performed to recover the CD146-positive cell population (CD146+) and CD146-negative cell population (CD146-). CD146 + SHED without cell sorting and CD146-SHED were examined and compared among three groups. To investigate the effect of CD146 on cell proliferation ability, an analysis of cell proliferation ability was performed using BrdU assay and MTS assay. The bone differentiation ability was evaluated using an alkaline phosphatase (ALP) stain after inducing bone differentiation, and the quality of ALP protein expressed was examined. We also performed Alizarin red staining and evaluated the calcified deposits. The gene expression of ALP, bone morphogenetic protein-2 (BMP-2), and osteocalcin (OCN) was analyzed using a real-time polymerase chain reaction. There was no significant difference in cell proliferation among the three groups. The expression of ALP stain, Alizarin red stain, ALP, BMP-2, and OCN was the highest in the CD146+ group. CD146 + SHED had higher osteogenic differentiation potential compared with SHED and CD146-SHED. CD146 contained in SHED may be a valuable population of cells for bone regeneration therapy.

A new masticatory performance scale to integrate food biting, comminution and mixing ability in removable partial denture wearers.

BACKGROUND: The existing masticatory performance (MP) tests cannot comprehensively evaluate objective masticatory function. OBJECTIVES: We aimed to examine the construct validity and responsiveness and determine the clinically minimum important difference (MID) and related factors of a newly developed MP scale to integrate food biting, comminution and mixing ability in patients with removable partial dentures (RPDs). METHODS: Masticatory performance tests using gummy jelly, peanuts and colour-changeable gum were performed before and 3 months after RPD treatment in 248 partially dentate patients. A 10-point ordinal subscale was created for each MP test based on the distributions of MP values, and the three subscales were integrated into a single scale (iMP scale). We analysed the correlations between MP values and iMP scores and determined the effect size for RPD treatments and the MID on the basis of patient perception of chewing ability. RESULTS: iMP scores exhibited moderate correlations with the three MP values (|ρ| = 0.73-0.79, p < .001) and with the change scores (|ρ| =0.61-0.64, p < .001). The mean iMP score significantly increased after RPD treatment (p < .001), and the effect size was 0.35. Of the 248 patients, 55 (22%) reported a slight improvement in chewing ability with a mean iMP score change of 2.1 points. Sex and the number of missing teeth were significantly associated with iMP scores (p < .05). CONCLUSIONS: The iMP scale comprehensively evaluated objective masticatory function, including food biting, comminution and mixing ability in RPD wearers, and an increase of two points on the iMP scale was considered to be the MID in RPD treatments.

Responsiveness of methods to evaluate chewing ability after removable partial denture treatments.

BACKGROUND: The ability of an instrument to detect a clinically important change in patient-reported outcomes following prosthetic treatment is critical for its use in clinical practice and research settings. OBJECTIVES: This study aimed to examine the responsiveness of instruments in evaluating patient perception of chewing ability after removable partial denture (RPD) treatment in a prospective cohort. METHODS: A single 100-mm visual analogue scale (VAS), 20-item food intake questionnaire (FIQ) and 6-point chewing difficulty scale (CDS) were administered to 248 partially edentulous patients to evaluate chewing ability pre- and post-RPD treatment. We conducted a statistical comparison between the pre- and post-treatment scores and determined the effect size (r) of RPD treatment for the instruments. RESULTS: A significant improvement in chewing ability after RPD treatment was identified by VAS and CDS (P < .05), but not by FIQ (P = .16), which identified an improvement after controlling for sex, age, the number of missing teeth and presence/absence of existing removable dentures. The effect size was medium for VAS (r = .54), weak for CDS (r = .14-.17) and absent for FIQ (r = -.09). The increase in r was significantly associated with impaired chewing ability before treatment (ρ = -0.87, P < .001). CONCLUSIONS: These results suggest that the 100-mm VAS, followed by CDS, is the most responsive instrument to detect an improvement in chewing ability after RPD treatment. Pre-treatment impairment of chewing ability was associated with better responsiveness of the instruments.

Pre-treatment impairment of oral health-related quality of life is associated with variations in minimal clinically important differences among patients with removable partial denture treatment.

BACKGROUND: The minimal clinically important differences (MID) of the Oral Health-related Quality of Life (OHRQoL) are the benchmark to meaningfully interpret treatment outcomes. However, there is no available information regarding the factors impact the MID variations after removable partial denture (RPD) treatment. OBJECTIVE: The purpose of this study was to determine the influence of the pre-treatment OHRQoL impairment on the MID in the oral health impact profile (OHIP) after RPD treatment. METHODS: In this prospective study, OHIP and Self-reported Oral Health (SROH) questionnaires were administered to patients before and 3 months after RPD treatment. The MID in each OHIP version (OHIP-49, OHIP-20, OHIP-14 and OHIP-5) was the mean score of patients who showed a minimum SROH improvement. Multiple linear regression analysis was conducted to determine the influence of the pre-treatment OHIP summary score on the MID score. RESULTS: Among 248 participants who completed both evaluations, 85 (34%) patients had minimum SROH improvements after RPD treatment. Multiple regression analysis indicated that each 10-point increase in the pre-treatment summary OHIP score was associated with an increase in the MID score of three points for OHIP-49 and four points for OHIP-20, OHIP-14 and OHIP-5 (P < .05), after controlling for age, sex and the number of missing teeth. Therefore, the MID increased as the pre-treatment OHRQoL was impaired. CONCLUSIONS: The MID was accounted for by approximately one-third of the pre-treatment summary score, independent of the OHIP version, in the interpretation of the effects of RPD treatment on patients' OHRQoL.

Comparison of the bone regeneration ability between stem cells from human exfoliated deciduous teeth, human dental pulp stem cells and human bone marrow mesenchymal stem cells.

Cleft lip and palate is the most common congenital anomaly in the orofacial region. Autogenous iliac bone graft, in general, has been employed for closing the bone defect at the alveolar cleft. However, such iliac bone graft provides patients with substantial surgical and psychological invasions. Consequently, development of a less invasive method has been highly anticipated. Stem cells from human exfoliated deciduous teeth (SHED) are a major candidate for playing a significant role in tissue engineering and regenerative medicine. The aim of this study was to elucidate the nature of bone regeneration by SHED as compared to that of human dental pulp stem cells (hDPSCs) and bone marrow mesenchymal stem cells (hBMSCs). The stems cells derived from pulp tissues and bone marrow were transplanted with a polylactic-coglycolic acid barrier membrane as a scaffold, for use in bone regeneration in an artificial bone defect of 4 mm in diameter in the calvaria of immunodeficient mice. Three-dimensional analysis using micro CT and histological evaluation were performed. Degree of bone regeneration with SHED relative to the bone defect was almost equivalent to that with hDPSCs and hBMSCs 12 weeks after transplantation. The ratio of new bone formation relative to the pre-created bone defect was not significantly different among groups with SHED, hDPSCs and hBMSCs. In addition, as a result of histological evaluation, SHED produced the largest osteoid and widely distributed collagen fibers compared to hDPSCs and hBMSCs groups. Thus, SHED transplantation exerted bone regeneration ability sufficient for the repair of bone defect. The present study has demonstrated that SHED is one of the best candidate as a cell source for the reconstruction of alveolar cleft due to the bone regeneration ability with less surgical invasion.

Responsiveness of methods to evaluate objective masticatory function in removable partial denture treatments.

Purpose The aim of this study was to examine the responsiveness of chewing tests after removable partial denture (RPD) treatment in this prospective cohort study.Methods Pre- and post-RPD treatment, objective masticatory function was evaluated in 248 patients via chewing tests involving peanuts, a gummy jelly, and a color-changeable gum. A statistical comparison was performed between the pre- and post-treatment scores, and the standardized response mean (SRM) was determined as the treatment effect size (ES).Results After RPD treatment, the median particle size in the sieving method using peanuts significantly decreased, and the glucose concentration in the gummy jelly method significantly increased (P < 0.001). The ESs of the sieving and gummy jelly methods were larger (|SRM| = 0.3-0.4) than that of the gum method (|SRM| = 0.1). In the subgroup analysis, the sieving and gummy jelly methods resulted in a broader effective range (|SRM| ≥ 0.3) than the gum method. In patients without pre-treatment dentures, the ES was medium in the sieving method (|SRM| = 0.6) and weak in the gummy jelly and gum methods (|SRM| = 0.3-0.4). The pre-treatment level of masticatory function was significantly correlated with ES (ρ = 0.93, P < 0.001).Conclusions These results suggest that the sieving and gummy jelly methods are more responsive than the gum method for RPD treatment and that the pre-treatment scores affect the responsiveness.

Minimal clinically important differences of oral health-related quality of life after removable partial denture treatments.

OBJECTIVES: This study aimed to determine the minimal clinically important difference (MID) of the oral health-related quality of life (OHRQoL) in removable partial dentures (RPDs) wearers, using the oral health impact profile (OHIP). METHODS: In this study, RPD patients were asked to complete the OHIP and self-reported oral health (SROH) questionnaires before the treatment and 3 months after the RPD treatment. The Wilcoxon signed ranked test compared the pre- and post-treatment status and the Spearman correlation analysis evaluated the relationship between the pre- and post- treatment change scores of the OHIP and SROH. The median OHIP change score in a subgroup that showed minimum SROH improvement was determined as the MID. RESULTS: Of the 277 participants, 248 (89.5 %) completed the pre-and post- treatment evaluations. SROH and OHIP scores showed significant improvements after RPD treatment (P < 0.05). The OHIP change scores showed significant moderate correlations with the SROH change scores (P < 0.05). The MIDs for the summary scores of OHIP-49, 20, 14, and 5 versions were 14, 7, 3, and 2 points, respectively. An additional 2-3 points were assigned to the four dimensions (oral function, orofacial pain, orofacial appearance, and psychological impact). CONCLUSIONS: An OHIP change of more than 14 points (OHIP-49), 7 points (OHIP-20), 3 points (OHIP-14), 2 points (OHIP-5) and 2-3 points (4 dimensions) was considered clinically meaningful in RPD treatments. CLINICAL SIGNIFICANCE: The proposed MID scores could be used as a benchmark for clinical decision making, interpretation of RPD treatment effects on OHRQoL, and sample size calculations in clinical trials.

Simultaneous interrelationship between the oral health behavior and oral health status of mothers and their children.

The purpose of this study was to examine the simultaneous interrelationships of oral health behavior and oral health between mothers and their children using the linear structural relations (LISREL) program. The subjects comprised 117 pairs of mothers and their children aged between 8 and 11 years. Dental status was expressed as DMFT. The Oral Rating Index (ORI) for mothers and ORI for children (ORI-C) were used as measures of gingival health. Hiroshima University Dental Behavioral Inventory (HU-DBI) was used for the assessment of mothers' oral health behavior. HU-DBI had a direct positive relationship to ORI, a direct negative relationship to DFT, and a direct positive association with ORI-C. Toothbrushing had a direct negative relationship to ORI-C. The hypothesized model was found to be closely consistent with the data. These results indicate that the periodontal health status of mothers is directly related to the oral health status of their children, and that toothbrushing by children is directly related to their gingival health.

High prevalence of Helicobacter pylori detected by PCR in the oral cavities of periodontitis patients.

BACKGROUND: Helicobacter pylori has been associated with the development of peptic ulcers and gastric cancer. Although it may be transmitted through the oral cavity, it is unknown whether the oral cavity acts as a permanent reservoir for this bacterium. The purpose of this study was to use nested polymerase chain reaction (PCR) to clarify whether the oral cavity acts as a reservoir for H. pylori. METHODS: The existence of H. pylori in the oral cavity was determined by nested PCR in 57 subjects and by culture method in 18 subjects. The presence of periodontopathic bacteria was also determined by 16S rRNA-based PCR method. RESULTS: Although H. pylori was rarely detected in the oral cavity by culture technique, it was frequently detected (35.1%) by nested PCR in the oral cavity, especially among periodontitis patients who had the bacterium in the gastrointestinal tract (46.4%). Among the subjects who harbored H. pylori in the stomach or duodenum, 41.2% of patients with periodontal pockets > or = 4 mm and 9.1% of subjects without pockets showed H. pylori in dental plaque, although a statistically significant difference was not observed. One patient who had periodontal pockets retained H. pylori in the oral cavity even after eradication of the bacterium from the stomach and duodenum. Most (8/10) of the patients who had H. pylori in dental plaque harbored Bacteroides forsythus in their oral cavities. CONCLUSION: Close attention should be given to periodontitis patients who harbor H. pylori in the oral cavity.