The oral carriage rate of Candida in healthy humans ranges from 40% to 60%. However for a prolonged period, the oral candidal prevalence in humans was documented essentially using data from studies in the West as their prevalence in inhabitants in different regions of the world, including Asia was not known. Yet, recent reports from a number of studies indicate the quality, quantity and prevalence of oral yeasts differ between Asia and other regions for reason that are still unclear. This mini review on such data from Asian studies on oral carriage of Candida provides another intriguing facet of the behavior of this ubiquitous yeast.
Tooth loss compromises human oral health. Although several prosthetic methods, such as artificial denture and dental implants, are clinical therapies to tooth loss problems, they are thought to have safety and usage time issues. Recently, tooth tissue engineering has attracted more and more attention. Stem cell based tissue engineering is thought to be a promising way to replace the missing tooth. Mesenchymal stem cells (MSCs) are multipotent stem cells which can differentiate into a variety of cell types. The potential MSCs for tooth regeneration mainly include stem cells from human exfoliated deciduous teeth (SHEDs), adult dental pulp stem cells (DPSCs), stem cells from the apical part of the papilla (SCAPs), stem cells from the dental follicle (DFSCs), periodontal ligament stem cells (PDLSCs) and bone marrow derived mesenchymal stem cells (BMSCs). This review outlines the recent progress in the mesenchymal stem cells used in tooth regeneration.
To evaluate the effect of single or dual field irradiation (IR) with the same dose on damage to miniature pig parotid glands.
Sixteen miniature pigs were divided into two IR groups (n=6) and a control group (n=4). The irradiation groups were subjected to 20 Gy X‐radiation to one parotid gland using single‐field or dual‐field modality by linear accelerator. The dose‐volume distributions between two IR groups were compared. Saliva from parotid glands and blood were collected at 0, 4, 8 and 16 weeks after irradiation. Parotid glands were removed at 16 weeks to evaluate tissue morphology.
The irradiation dose volume distributions were significantly different between single and dual field irradiation groups (t=4.177, P=0.002), although dose volume histogramin (DVH) indicated the equal maximal dose in parotid glands. Saliva flow rates from IR side decreased dramatically at all time points in IR groups, especially in dual field irradiation group. The radiation caused changes of white blood cell count in blood, lactate dehydrogenase and amylase in serum, calcium, potassium and amylase in saliva. Morphologically, more severe radiation damage was found in irradiated parotid glands from dual field irradiation group than that from single field irradiation group.
Data from this large animal model demonstrated that the radiation damage from the dual field irradiation was more severe than that of the single field irradiation at the same dose, suggesting that dose‐volume distribution is an important factor in evaluation of the radiobiology of parotid glands.
To characterize the odontogenic capability of apical bud and phenotypical change of apical bud cells (ABCs) in different microenvironment.
Incisor apical bud tissues from neonatal SD rat were dissected and transplanted into the renal capsules to determine their odontogenic capability. Meanwhile ABCs were cultured and purified by repeated differential trypsinization. Then ABCs were cultured with conditioned medium from developing apical complex cells (DAC‐CM). Immunocytochemistry, reverse transcriptase polymerase chain reaction (RT‐PCR) and scanning electron microscope (SEM) were performed to compare the biological change of ABC treated with or without DAC‐CM.
First we confirmed the ability of apical bud to form crown‐like structure ectopically. Equally important, by using the developing apical complex (DAC) conditioned medium, we found the microenvironment created by root could abrogate the “crown” features of ABCs and promote their proliferation and differentiation.
ABCs possess odontogenic capability to form crown‐like tissues and this property can be affected by root‐produced microenvironment.
To clarify the role of PTCH in patients with NBCCS‐related and non‐sydromic keratocystic odontogenic tumors.
Mutation analysis was undertaken in 8 sporadic and 4 NBCCS‐associated KCOTs.
Four novel and two known mutations were identified in 2 sporadic and 3 syndromic cases, two of which being germline mutations (c.2179delT, c.2824delC) and 4 somatic mutations (c.3162dupG, c.1362–1374dup, c.1012 C>T, c.403C>T).
Our findings suggest that defects of PTCH are associated with the pathogenesis of syndromic as well as a subset of non‐syndromic KCOTs.
To evaluate the effects of maxillary sinus floor elevation by a tissue‐engineered bone complex of β‐tricalcium phosphate (β‐TCP) and autologous osteoblasts in dogs.
Autologous osteoblasts from adult Beagle dogs were cultured in vitro. They were further combined with β‐TCP to construct the tissue‐engineered bone complex. 12 cases of maxillary sinus floor elevation surgery were made bilaterally in 6 animals and randomly repaired with the following 3 groups of materials: Group A (osteoblasts/β‐TCP); Group B (β‐TCP); Group C (autogenous bone) (n=4 per group). A polychrome sequential fluorescent labeling was performed post‐operatively and the animals were sacrificed 24 weeks after operation for histological observation.
Our results showed that autologous osteoblasts were successfully expanded and the osteoblastic phenol‐types were confirmed by ALP and Alizarin red staining. The cells could attach and proliferate well on the surface of the β‐TCP scaffold. The fluorescent and histological observation showed that the tissue‐engineered bone complex had an earlier mineralization and more bone formation inside the scaffold than β‐TCP along or even autologous bone. It had also maximally maintained the elevated sinus height than both control groups.
Porous β‐TCP has served as a good scaffold for autologous osteoblasts seeding. The tissue‐engineered bone complex with β‐TCP and autologous osteoblasts might be a better alternative to autologous bone for the clinical edentulous maxillary sinus augmentation.