Study of factors related to the reflection abilities of dental trainees

INTRODUCTION

This study analysed the internal and external factors related to the reflection abilities of dental trainees.

PARTICIPANTS AND METHODS

We created transcripts from oral presentations by the dental trainees of Hiroshima University Hospital (n = 35, 2012-2013) at a significant event analysis conference. The reflection depths were compared between the trainees of the university hospital and external clinical combination groups. We determined and statistically analysed the reflection depths.

RESULTS

At the end of training, a Mann-Whitney U-test revealed a significant difference in the median reflection depths of the groups (U = 66, W = 342 and P = 0.007). The results of multiple regression analysis indicated a significant relation between the reflection depth and external training completion (P = 0.024). There were no relations with other factors, including gender and academic background.

CONCLUSION

Experiences in external clinics create a close connection between the staff and trainees because communities of practice can cause deeper reflections. We need to create small groups in large-scale organisations such as university hospitals. This construct can be adapted not only for Japanese dental trainees but also for global dental and other medical trainees.

Effect of oxygen vacancy segregation in Au or Pt/oxide hetero-interfaces on electronic structures

We investigated the effects of oxygen vacancy segregation on electronic structures in the vicinity of hetero-interfaces between noble metals (Au and Pt) and yttria stabilized zirconia by performing first-principles calculations and Bader analysis.

A Role for Proteoglycans in Mineralized Tissue-Titanium Adhesion

Biomechanical properties of the bone-titanium interface have rarely been studied, due to the technical limitations involved; whether biological bonding mechanisms exist has not been determined. We hypothesized that a selected set of proteoglycan/glycosaminoglycan complexes plays a role in establishing the adhesion between bone and titanium, and utilized the rat bone-marrow-derived osteoblastic culture model to gain an insight into the hypothesis. Gene expression of selected proteoglycan core proteins was up-regulated in the osteoblasts cultured on titanium compared with those on polystyrene. Various sulfated glycosaminoglycans were immunochemically localized at mineralized tissue-titanium interfaces. The administration of various glycosaminoglycan-degrading enzymes into the cultures resulted in a 25–45% reduction of the tissue-titanium interfacial strength, measured by a nanoscratch test; while the hardness and elastic modulus of the mineralized tissue, evaluated by nano-indentation, were not altered. In conclusion, glycosaminoglycan degradation resulted in a decreased interfacial strength between cultured mineralized tissue and titanium, but did not alter the intrinsic strength of the mineralized tissue, suggesting a role for proteoglycan/glycosaminoglycan complexes in the establishment of tissue-titanium adhesion.

Treponema medium Glycoconjugate Inhibits Activation of Human Gingival Fibroblasts Stimulated with Phenol-Water Extracts of Periodontopathic Bacteria

Oral treponemes are well-known as causative agents of periodontal diseases; however, the details have not been fully clarified. Here, we examined the effects of Treponema medium glycoconjugate on the activation of human gingival fibroblasts using phenol-water extracts from Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum subsp. nucleatum, and Actinobacillus actinomycetemcomitans. The phenol-water extracts activated human gingival fibroblasts to mediate IL-8 production, as well as IL-8 mRNA expression, phosphorylation of p38 mitogen-activated protein kinase, and expression of intercellular adhesion molecule-1. T. medium glycoconjugate exhibited no activation of human gingival fibroblasts, while phenol-water extract-induced activation of human gingival fibroblasts was clearly inhibited by T. medium glycoconjugate. Furthermore, binding of biotinylated phenol-water extracts to CD14 in the presence of LPS-binding protein was blocked with T. medium glycoconjugate. These results suggest that T. medium glycoconjugate has an inhibitory effect on host cell activation by periodontopathic bacteria caused by binding to CD14- and LPS-binding protein.

Detectable Dioxins in Human Saliva and Their Effects on Gingival Epithelial Cells

Dioxin, a powerful hormone-disrupting chemical, exhibits serious health effects when it reaches body fat. Here we analyzed coplanar polychlorinated biphenyls (PCBs) and polychlorinated-dibenzo- p-dioxins (PCDDs) in human saliva as compared with blood specimens, and examined their effects on human gingival epithelial cells (HGEC). High levels of tri- and tetrachlorinated PCBs were found in saliva, whereas we detected predominantly hexa- and heptachlorinated PCBs in blood. Among PCDDs, the saliva and blood specimens contained mainly 1,2,3,4,6,7,8,9-octachlorodibenzo- p-dioxin (OCDD). Among the toxic dioxins proposed by the World Health Organization (WHO) in 1998, 2,3′,4,4′,5-pentachlorobiphenyl (PCB 118) and OCDD, which were mainly found in saliva, significantly induced IL-8 production in HGEC. Furthermore, these two dioxins markedly augmented IL-8 production stimulated with fimbriae from Porphyromonas gingivalis, which is well-known as a pathogenic factor in periodontal diseases. These results suggest that dioxins in saliva may be a risk factor for periodontal diseases.

Hyper-expression of Osteocalcin mRNA in Odontoblasts of Hyp Mice

The Hyp mouse is a murine homologue of human X-linked hypophosphatemia that displays hypo-mineralization in bone and dentin. In this study, we tested the hypothesis that the defect in Hyp mice leads to alterations in the expression of dentin matrix proteins that may be associated with the hypo-mineralization changes in the tissues. Quantitative RT-PCR analyses showed that expression of the osteocalcin gene in Hyp mice tooth germ samples was significantly higher than in wild-type mice, whereas the gene expressions of osteonectin, osteopontn, dentin matrix protein 1, and type I collagen in both types of mice were similar. Further, cultured Hyp mice tooth germ samples exhibited a higher expression of the osteocalcin gene than did those from wild-type mice, which was in accord with the results of our in vivo analysis. These findings suggest that osteocalcin mRNA is highly expressed in Hyp mice odontoblasts and may be associated with dentin hypo-mineralization.

Harder and Stiffer Bone Osseointegrated to Roughened Titanium

Mechanisms underlying the beneficial anchorage of roughened titanium implants have not been identified. We hypothesized that the implant surface roughness alters intrinsic biomechanical properties of bone integrated to titanium. Nano-indentation performed on two- and four-week post-implantation bone specimens of rats revealed that bone integrated to acid-etched titanium was approximately 3 times harder than that integrated to the machined titanium, both at the osseointegration interface and at the inner area of the peri-implant bone. The hardness of the acid-etched surface-associated bone was equivalent to that of untreated cortical bone at week 4, while the bone hardness around the machined surface was equivalent to that of the untreated trabecular bone. The elastic modulus of the integrated bone was 1.5 to 2.5 times greater around the acid-etched surface than around the machined surface. Analysis of the data suggests that the implant surface roughness affects the biomechanical quality of osseo-integrated bone, and that the bone integrated to the acid-etched surface is harder and stiffer than the bone integrated to the machined surface.

Genes Differentially Expressed in Titanium Implant Healing

Bone generation occurs around titanium implants; however, its underlying mechanisms are unknown. We hypothesized that molecular determinants distinct from those undertaking normal bone healing regulate osseointegration. Using differential display-polymerase chain-reaction in the male rat model, we isolated 3 genes that are differentially expressed in bone healing with implants, but not in osteotomy healing. A homology search indicated that these 3 genes are apolipoprotein E, prolyl 4-hydroxylase α-subunit, and an unknown transcript. Differential expression of these genes was remarkable during early healing stages up to week 2, and accelerated with rough acid-etched surfaces compared with machined surfaces. The differential expression was confirmed in the female rats, with enhanced expression for the acid-etched surfaces. The osseointegration-unfavorable condition created by gonadal estrogen deficiency reduced the level of differential expression. This study provides evidence that selected gene transcripts are induced by titanium implants under regulatory control strongly associated with the nature of osseointegration.

Longitudinal study of factors affecting taste sense decline in old-old individuals

The sense of taste plays a pivotal role for personal assessment of the nutritional value, safety and quality of foods. Although it is commonly recognised that taste sensitivity decreases with age, alterations in that sensitivity over time in an old-old population have not been previously reported. Furthermore, no known studies utilised comprehensive variables regarding taste changes and related factors for assessments. Here, we report novel findings from a 3-year longitudinal study model aimed to elucidate taste sensitivity decline and its related factors in old-old individuals. We utilised 621 subjects aged 79-81 years who participated in the Septuagenarians, Octogenarians, Nonagenarians Investigation with Centenarians Study for baseline assessments performed in 2011 and 2012, and then conducted follow-up assessments 3 years later in 328 of those. Assessment of general health, an oral examination and determination of taste sensitivity were performed for each. We also evaluated cognitive function using Montreal Cognitive Assessment findings, then excluded from analysis those with a score lower than 20 in order to secure the validity and reliability of the subjects' answers. Contributing variables were selected using univariate analysis, then analysed with multivariate logistic regression analysis. We found that males showed significantly greater declines in taste sensitivity for sweet and sour tastes than females. Additionally, subjects with lower cognitive scores showed a significantly greater taste decrease for salty in multivariate analysis. In conclusion, our longitudinal study revealed that gender and cognitive status are major factors affecting taste sensitivity in geriatric individuals.

Dietary Intake Is Associated with Occlusal Force Rather Than Number of Teeth in 80-y-Old Japanese

There has been a growing interest in the association between the number of teeth and dietary intake in older populations. However, people around the age of 80 y have frequently lost most of their teeth, and dental prostheses replacing the missing teeth play an important role in masticatory function. Therefore, masticatory function cannot be evaluated by the number of teeth alone. The occlusal force of the complete dental arches is an index of masticatory function, reflecting not only the number of teeth, but the effect of removable dentures. The purpose of this cross-sectional study was to determine the relative importance of the number of teeth and occlusal force in association with dietary intake in 80-y-old Japanese people.

This study included 760 community-dwelling Japanese people aged 79 y to 81 y. The authors measured bilateral maximal occlusal force in the intercuspal position using pressure-sensitive sheets. Removable denture wearers kept their dentures in place during the measurements. Energy-adjusted food groups and nutrient intake during the preceding month were assessed by a brief self-administered diet history questionnaire. The authors assessed linear trends in food and nutrient intake in relation to the number of teeth and occlusal force after adjusting for gender and socioeconomic status (education level, financial status, family structure, resident area and BMI). P values of < 0.05 were considered to be statistically significant.

The authors found that the number of teeth was not associated with the energy-adjusted intake of any food group examined. In contrast, a decline in occlusal force was significantly associated with a lower intake of vegetables, fish and shellfish, protein, polyunsaturated fatty acids, dietary fiber and most vitamins and minerals ( P for trend < 0.05). We conclude that food and nutrient intake was more closely associated with occlusal force than the number of teeth in community-dwelling Japanese people aged 79 y to 81 y.

Knowledge Transfer Statement: This cross-sectional study of older Japanese people showed that, after controlling for considerable covariates, occlusal force rather than the number of teeth is positively associated with energy-adjusted intake of vegetables, fish and shellfish, protein, polyunsaturated fatty acids, dietary fiber and most of vitamins and minerals. This means that reduced occlusal force may unconsciously lead older people toward a habitual unhealthy dietary intake. Older people have frequently lost most of their teeth and require prosthetics to restore masticatory function. Bilateral occlusal force is therefore a better measure of masticatory function than the number of remaining teeth. Our findings suggest that prosthetic rehabilitation is a significant factor in the prevention and management of chronic diseases and frailty through better dietary intake in older populations.

Factors related to taste sensitivity in elderly: cross-sectional findings from SONIC study

The sense of taste is important, as it allows for assessment of nutritional value, as well as safety and quality of foods, with several factors suggested to be associated with taste sensitivity. However, comprehensive variables regarding taste and related factors have not been utilised in previous studies for assessments of sensitivity. In the present study, we performed cross-sectional analyses of taste sensitivity and related factors in geriatric individuals who participated in the SONIC Study. We analysed 2 groups divided by age, 69-71 years (young-old, n = 687) and 79-81 years (old-old, n = 621), and performed a general health assessment, an oral examination and determination of taste sensitivity. Contributing variables were selected by univariate analysis and then subjected to multivariate logistic regression analysis. In both groups, females showed significantly better sensitivity for bitter and sour tastes. Additionally, higher cognitive scores for subjects with a fine taste for salty were commonly seen in both groups, while smoking, drinking, hypertension, number of teeth, stimulated salivary flow salt intake and years of education were also shown to be associated with taste sensitivity. We found gender and cognitive status to be major factors affecting taste sensitivity in geriatric individuals.

Clinical Value of Pet with 18F-Fluorodeoxyglucose and L-Methyl-11C-Methionine for Diagnosis of Recurrent Brain Tumor and Radiation Injury

We studied 15 patients clinically suspected to have recurrent brain tumor or radiation injury, using positron emission tomography (PET) with 18F-fluorodeoxyglucose (18FDG) and L-methyl-11C-methionine (11C-Met). PET with 11C-Met (Met-PET) clearly delineated the extent of recurrent brain tumor as focal areas of increased accumulation of 11C-Met, and was useful for early detection of recurrent brain tumor. PET with 18FDG (FDG-PET) showed focal 18FDG-hypermetabolism in one patient with malignant transformation of low grade glioma, and demonstrated its usefulness for evaluation of malignant transformation. 18FDG-hypometabolism was observed in all patients with radiation injury, but was also found in one patient with recurrent malignant brain tumor. 11C-Met uptake in 3 patients with radiation injury was similar to that of the normal cortical tissue. FDG-PET can be used to initially exclude recurrent brain tumor which is seen as 18FDG-hypermetabolism. The combined use of Met-PET in addition to FDG-PET can improve the accuracy of differentiation of recurrent brain tumor with 18FDG-hypometabolism from radiation injury.

Angioscopic External Valvuloplasty in the Treatment of Varicose Veins

Objective:

To report on the surgical treatment of varicose veins by angioscopic valvuloplasty to preserve the long saphenous vein (LSV) and the efficacy of this method compared with conventional stripping and high ligation.

Methods:

A total of 306 limbs in 187 patients with reflux at the sapheno-femoral junction to below knee level were operated on using intraoperative angioscopy to diagnose valve insufficiency. Angioscopic external valvuloplasty was attempted for the subterminal valves in the LSV by three techniques: total plication of the dilated annulus by running polypropylene sutures (technique 1), plication by autogenous femorofascial sleeve or Dacron-reinforced silicone (technique 2), and plication of the commissure with shortening of the cusps from outside the vein wall (technique 3). Partial stripping or segmental ligation was performed for varicose veins below knee level and the incompetent perforating veins were treated simultaneously by suprafascial ligation.

Results:

The subterminal valves were classified as follows: valves with elongated and atrophic cusps – type I, 136 (44%); valves with expanded and depressed commissures with cusp changes – type II, 108 (35%); valves that had cusps with other deformities – type III, 38 (13%); and absence of valves between the saphenofemoral junction and mid-thigh level, 24 limbs (8%). Valvuloplasty of the LSV was successfully performed in 62 limbs (20%). There were two cases with occlusion of the LSV (3%) and four with recurrence of varicose veins (6%) at 2–89 (mean 55, SD 21) months follow-up.

Conclusions:

Angioscopic external valvuloplasty is effective in the treatment of varicose veins to preserve the LSV. Further data are needed for complete evaluation of this procedure.

Immunoglobulin A Nephropathy in a Living Kidney Donor Diagnosed and Treated After Transplantation: A Case Report

OBJECTIVE

We report the clinical course and pathologic findings of a kidney transplant donor who was diagnosed with immunoglobulin A (IgA) nephropathy by means of preimplantation biopsy and was later treated with methylprednisolone and tonsillectomy.

CASE REPORT

The patient was a 57-year-old woman who met the criteria for kidney donation and was accepted as a donor. Donor nephrectomy was performed, and the preimplantation biopsy revealed that the donor had IgA nephropathy. One month after the nephrectomy, the donor's laboratory findings indicated proteinuria and hematuria. Because these findings indicated active IgA nephropathy, we decided to perform tonsillectomy and methylprednisolone pulse therapy. Soon after these treatments, the patient's proteinuria and hematuria were no longer observed.

CONCLUSIONS

Subclinical IgA nephropathy can be incidentally found on preimplantation biopsies of living kidney donors. As demonstrated in this case, IgA nephropathy can become exacerbated and requires therapeutic intervention after kidney donation. Informed consent and careful observation should be used before and after transplantation, even for donors who have been determined to be eligible for kidney donation.