Dental treatments in patients with special needs provided by university medical center in Southern Taiwan: a retrospective study.

OBJECTIVES: We perform special-need dental treatment at outpatient department (OPD), under general anesthesia (GA) when necessary, and provide domiciliary dental care. We aim to evaluate the profile and the characteristics of special needs patients (SNPs). MATERIALS AND METHODS: We consecutively enrolled 3117 SNPs from January 1, 2019 to December 31, 2022. Eighty patients with rare or genetic diseases were excluded. Demographic data were retrospectively collected. RESULTS: There were totally 3037 SNPs (mean age: 48.2 years; range, 1-100; male-to-female ratio, 1.5); 89.1% (n = 2705) SNPs received dental care at the OPD (OPD-SNPs), 7.9% (n = 239) received dental treatment under GA, and 3.0% (n = 93) received domiciliary dental care. Among those SNPs who received dental treatment under GA (n = 239), 91.2% (n = 218) were mental/intellectual disabled, and most underwent cavity filling (69.5%) and dental extractions (56.5%). OPD-SNPs with mental/intellectual disabilities (n = 1340) received significantly more items of dental treatment than those without (n = 1365). SNPs with more severe disabilities received more fluoride application and ultrasonic scaling (both p < 0.001, trend tests). Interestingly, among OPD-SNPs with mental/intellectual disabilities (n = 1340), more severe patients received more fluoride application (p < 0.001) and ultrasonic scaling (p < 0.001) but fewer root canal treatment (p = 0.007, trend test). CONCLUSIONS: GA benefited SNPs with more dental procedures, including invasive items. SNPs with mental/intellectual disabilities can tolerate more measures and SNPs with more severe mental/intellectual disabilities received more preventive measures but less invasive measures. Similarly, more severe SNPs with other disabilities received more preventive measures but not invasive measures. CLINICAL RELEVANCE: Our findings may provide useful information for special needs dentists and for doctor-patient communication.

Dental cement's biological and mechanical properties improved by ZnO nanospheres.

Metal oxide nanoparticles are a new class of important materials used in a wide variety of biomedical applications. Bulk zinc oxide (ZnO) particles have been used for temporal or permanent luting cement because of their excellent mechanical strength and biocompatibility. ZnO nanoparticles have distinct optical and antibacterial properties and a high surface-to-volume ratio. We investigated the mechanical and antibacterial properties of luting cement with different ratios of ZnO nanospheres. We showed that luting cement with 5% and 10% ZnO nanospheres was less soluble in low-pH (pH 3) artificial saliva. Antibacterial activity was 40% higher for Streptococcus mutans and 90% higher for Porphyromonas gingivalis when >10% (w/v) of the bulk particles were replaced with ZnO nanospheres in ZnO polycarboxylate cement. ZnO nanospheres were also biocompatible with mammalian cells. Additionally, the compressive strength was 1.2 times greater and the diametral tensile strength was 1.5 times greater for cements with 10% ZnO nanospheres than for conventional ZnO polycarboxylate cement. We propose a new method for improving dental luting cement by integrating it with ZnO nanospheres. This method simultaneously adds their greater antibacterial, mechanical, and acid resistance properties and retains an outstanding degree of biocompatibility.

Single Crystalline Iron Silicide and Beta-Iron Disilicide Nanowires Formed through Chemical Vapor Deposition.

In this paper, we report the synthesis of iron silicide and ß-iron disilicide nanowires with chemical vapor deposition; remarkably, the latter has drawn much attention but has seldom been achieved. We also propose the formation mechanisms for the two phases. To investigate the effects of the growth parameters on compositions and morphologies of the iron silicide nanowires, we changed and studied the reaction time, substrate temperature, position of samples, and pressure. The reaction concentration was found to be altered by all of the parameters; thus, we observed different nanowires in terms of morphologies and compositions with scanning electron microscopy. To confirm the growth direction and crystal structure of the nanowires, we conducted x-ray diffraction and high-resolution transmission electron microscopy studies. With the potential of being utilized as circuit elements in electronic devices for Schottky barriers, ohmic contacts, and interconnection among silicon-based transistors, the silicide work at nanoscale is beneficial for nanoelectronics. Understanding the effects of these growth parameters facilitates the control of nanowire growth with better quality.

A continuous flow system for assessing fluoride release/uptake of fluoride-containing restorative materials.

OBJECTIVES: The aim of this study was to develop a continuous flow system to mimic the kinetics of salivary flow in the mouth and to study the fluoride (F) release/uptake characteristics of both a conventional (Fuji IX) and a resin-modified glass ionomer (Vitremer) in such system. METHODS: Five discs were made for each material. The disc was suspended in a drip chamber sustaining 2 ml of deionized water. The flow rate was controlled at 20 ml/h by an infusion pump. The F release in the drip chamber was assessed at designated time points for up to 6 days. The discs were subjected to 1 min exposures of 0.2% sodium fluoride (NaF); the F re-release was assessed for another 12 h. RESULTS: Following a brief initial burst of F release, the rate decreased rapidly. Vitremer reached a steady low after 8 h, while Fuji IX reached a steady low after 90 min. Cumulative F release was measured from both the effluence and the drip chamber and showed that Vitremer released and took up more F than Fuji IX, both before and after F treatment. Cumulative amounts of fluoride in the drip chamber were much less than that in the effluence. The daily release rate patterns from the two materials were parallel. However, the hourly release rate of Vitremer decreased more gradually than Fuji IX. After sodium fluoride (NaF) treatment, F can be recharged easily and re-released rapidly within 90 min. CONCLUSION: This study indicates that the continuous flow method can be used to assess F release/uptake of the material. This method may represent a closer model to in vivo conditions.

A peripheral ameloblastic fibro-odontoma in a 3-year-old girl: case report, immunohistochemical analysis, and literature review.

Ameloblastic fibro-odontoma (AFO) predominantly occurs in the jaw bones of children and young adults. Extraosseous AFO is extremely rare. We describe a peripheral ameloblastic fibro-odontoma in the maxillary gingiva of a 3-year-old girl. The clinical appearance resembled fiery red reactive gingival lesions. The histopathological examination of the excised lesion showed small islands and cords of odontogenic epithelium with cellular myxoid stroma in the subepithelial tissue. The mass contained calcified material and an enamel-like deposit. Many small blood vessels appeared in the connective tissue surrounding the odontogenic epithelium. The immunohistochemical assays showed strong reactivity for amelogenin, ß-catenin, CD44, and CD31 in the tissue sections. There was no recurrence after the 1-year follow-up. Because this lesion clinically resembles other nonneoplastic lesions and is very rare in gingiva, establishing a correct diagnosis is achieved only based on specific histological characteristics. Conservative excision of the tumor is the treatment of choice.

Human enamel rod presents anisotropic nanotribological properties.

The AFM combined nanoindentation was performed to observe the ultrastructure of enamel rod from various section plans and positions while probing their mechanical and tribological properties of the area. The nanohardness and the elastic modulus of the head region of the enamel rods are significantly higher than that of the tail region and the axial-sectional plane. Both nanohardness and elastic modulus gradually decrease from enamel surface toward dentino-enamel junction. Such a variation correlates well with the decreasing trend of calcium composition from our element analysis. The friction coefficient and nanowear of the enamel showed an inversed trend to the hardness with respect to their relative topological position in the long axis of enamel rod toward DEJ. The relationship between the nanowear depth and the distance from the outer enamel surface to DEJ presented exponential function. The results presented clarify the basic nanomechanical and nanotribological properties of human enamel rods and provide a useful reference for the future development of dental restorative materials.