ABSTRACT
Objective:To prepare a peptide fluorescent probe based on aggregation-induced emission and to investigate its application in the detection of early caries.Methods:Eight aspartate-serine-serine (DSS) were combined with aggregation-induced emission material to prepare peptide fluorescent probes, and an artificial demineralization model was established in vitro. The samples were immersed in the peptide fluorescent probe solution for 1 min, and a fluorescence imaging system was applied to examine the tooth samples and collect images and fluorescence data. Scanning electron microscopy was also applied to observe the phenotype of the teeth, and electron microscopy was applied to detect the calcium-phosphorus ratio on the enamel surface of the teeth. Polarized light microscopy was also applied to observe the enamel area of the teeth. Results:The fluorescence intensity of demineralized teeth was clearly observed to be lower than that of normal teeth in the peptide fluorescent probe-treated area, and the difference was statistically significant ( P < 0.05). The results of scanning electron microscopy showed that the enamel surface of the demineralized group had more irregular pores, while the enamel surface of the undemineralized group was flatter with only some irregular accumulation of flakes. The results of polarized light microscopy showed that a clear birefringence could be observed in the enamel region of normal teeth, while a black area or the disappearance of the birefringence effect accompanied by a partial black dark shadow could be observed in the enamel region of demineralized teeth. Conclusions:An aggregation-induced luminescence-based peptide fluorescent probe was successfully prepared, which can precisely localize the enamel and show some application value in early caries detection.
ABSTRACT
Orthodontic tooth movement is achieved by remodeling periodontal ligament, alveolar bone and other periodontal tissues in response to mechanical loading. The periodontal ligament is the fibrous connective tissue connecting cementum and alveolar bone, which plays an important role in the transmission, absorption and dispersion of supporting teeth and biting force. When orthodontic forces are applied to the teeth, load transfer occurs from the tooth through the periodontal ligament to the alveolar bone. The remodeling of periodontal ligament interacts with the alveolar bone formation and absorption alternately. As the initial factor of orthodontic tooth movement, the stress/strain of periodontal ligament is involved in the process of alveolar bone remodeling and affects the direction and speed of tooth movement. Therefore, the biomechanical properties of the periodontal ligament have received extensive attention. In this paper, the related researches on the structural changes and biomechanical characteristics of the periodontal ligament during orthodontic tooth movement were reviewed as well as the researches on the mechanical constitutive model of the periodontal ligament. The mechanical response and biomechanical mechanism of the periodontal ligament were discussed in order to provide a theoretical basis for accurate numerical simulation of orthodontic tooth movement.
ABSTRACT
<p><b>OBJECTIVE</b>This study aimed to evaluate the potency of optical coherence tomography (OCT) to detect early occlusal caries compared with clinical visual examination.</p><p><b>METHODS</b>Approximately 97 sites of occlusal fissures on 77 extracted accessional human teeth were scored by three examiners using conventional visual examination and OCT. Results of histological examination on these sites obtained by polarimicroscope served as a gold standard to analyze the sensitivity (SE), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV). Results of the area under receiver operating characteristic (ROC) curve (AUC) by visual examination and OCT were also analyzed. The Spearman's rank correlation coefficient with histology and the inter-examiner reliability were compared.</p><p><b>RESULTS</b>For sites of enamel demineralization limited to the outer 1/2 of the enamel layer, the detection rate of OCT (14/25) was obviously higher than that of the clinical and visual examination (3/25). SE, SP, PPV and NPV of OCT during diagnosis of the early occlusal caries (0.83, 0.64, 0.87 and 0.57) were higher than that of the visual examination (0.79, 0.60, 0.85 and 0.50). AUC (95%CI) of OCT and the visual examination were 0.737 (0.569-0.822) and 0.696 (0.614-0.859), respectively. No statistically significant difference was observed between the results. Results of OCT correlated well with histology (r=0.559, P<0.05). The inter-examiner reliability of OCT was medium.</p><p><b>CONCLUSIONS</b>OCT can accurately detect early occlusal lesions atraumatically with high sensitivity and effectiveness. OCT exhibits the potential of auxiliary clinical diagnosis enhancing detection rate and finally implementing early diagnosis and early intervention of early occlusal lesions in clinical practice.</p>
Subject(s)
Humans , Dental Caries , Dental Enamel , ROC Curve , Reproducibility of Results , Tomography, Optical CoherenceABSTRACT
Medical ultrasound imaging suffers from poor resolution due to its inherit imaging mechanism.In order to obtain the important diagnostic image in detail,restoration procedure needs to be performed.However,in practical ultrasound imaging,it's difficult to demonstrate the degradation process in detail.Therefore,blind image deconvolution is applied to estimate the original image from the degraded image with unknown point spread function or little available prior knowledge.In this paper,the main algorithms of medical ultrasound image restoration based on blind deconvolution are reviewed and classified into two categories,priori or joint with the image,according to the identification methods,and the basic theories and improved methods are analyzed and discussed.Finally,the future directions in blind restoration for medical ultrasound images are proposed.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the efficacy of optical coherence tomography (OCT) in imaging and quantitatively evaluating early enamel caries and provide experimental evidence for the clinical diagnosis of early caries.</p><p><b>METHODS</b>The smooth surface of bovine teeth showing early artificial caries and demineralization changes was scanned by an all fiber-based OCT for images and optical profiles, which were compared with images from a polarized light microscope (PLM) and mineral loss from an atomic absorption spectrometer. Data were analyzed by paired-sample t-test and Pearson correlation analysis using SPSS software.</p><p><b>RESULTS</b>The images of enamel with early caries and demineralization from OCT coincided with those from PLM. The integrated reflectivity loss in the early caries group was significantly lower than that in the demineralized group (P < 0.05), whereas no significant difference in demineralized depth was found between the two groups (P > 0.05). A linear correlation was observed between integrated reflectivity loss and mineral loss (P < 0.05).</p><p><b>CONCLUSION</b>OCT can be used to nondestructively and accurately image early caries and quantify lesion extent and degree, suggesting the extensive use of this approach in the clinical diagnosis of early caries.</p>
Subject(s)
Animals , Cattle , Dental Caries , Dental Enamel , Tomography, Optical Coherence , Tooth DemineralizationABSTRACT
Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-β (TGF-β) superfamily, acting as important regulators in embryogenesis and bone and cartilage formation and repair.The complexity of BMPs action has early been unveiled by generous cell and molecular biology approaches and transgenic animal studies.Genetic engineering allows for the mass production of BMPs for clinical use of bone repair, but the desirable scaffold material is also needed to ensure controlled release and maximum biological activity of BMPs at the surgical site.Currently, BMP-2 and BMP-7 have been approved by United States Food and Drug Administration for clinical therapy in long bone fracture, spinal fusion and oral and maxillofacial surgery.The results are satisfactory, but the side effects have been also widely concerned.The functions and clinical applications of BMPs in bon repair are reviewed.
ABSTRACT
BACKGROUND:Sodium alginate and chitosan are the polycation and polyanion natural polymer materials respectively, and they can be crosslinking agents complementing each other to form composite gel and avoid the cytotoxicity resulting from some common crosslinking agents . OBJECTIVE:To prepare the chitosan-sodium alginate composite gel and evaluate its cytotoxicity in vitro. METHODS:Chitosan was dissolved in 0.25 mol/L acetic acid to make a 30 g/L mass concentration solution, and 0.1 mol/L NaOH solution was added to neutralize its acidity. Neutralization of the chitosan solutions leads to the formation of a precipitate in ultrasmal particles. Then the chitosan and 3%sodium alginate solution in deionized water were mixed in 1:1 volume ratio by high frequency oscil ating to produce composite gel. The composite gel were detected by scanning electron microscopy and Fourier transform infrared spectrometry after freeze-drying. The 24-hour and 72-hour leaching solutions of composite gel, 24-hour and 72-hour leaching solutions of polyethylene and phenol solution were added to the L-929 cells’ culture medium respectively in order to evaluate the cytotoxicity of composite gel in vitro. RESULTS AND CONCLUSION:The results of Fourier transform infrared spectrometry showed the variation of characteristic peak values of composite gel which were different from sodium alginate and chitosan;and under scanning electron microscope, a spatial network structure formed with abundant intervals. Result of the cytotoxicity valuation was qualified for the chitosan-sodium alginate composite gel. These findings indicate that the chitosan-sodium alginate composite gel can be used as tissue engineering scaffold materials.
ABSTRACT
Objective Quantitative analysis of optical coherence tomography (OCT) images of naturally occurred early enamel caries was performed to find quantitative parameter indicator for detecting early caries by OCT.Methods Three human premolars with enamel natural caries in D0,D1,and D2 stages were selected respectively and scanned by OCT.The ratios of the average gray value of the caries region (object region) and sound region (background region),namely,the object-background contrast (OBC) were calculated in OCT images and selected as the quantitative parameters to analyze the OBC trend of different degree of enamel caries.Results Within the fixed depth,the OBC value showed a trend of first increase and then decrease with the severity of dental caries,indicating that OBC value increased with the severity of dental caries from normal to D1 stage,and then decreased from D1 to D2 stage.Conclusion The OBC value can be used as a new quantitative indicator for OCT to estimate the severity of naturally occurred early caries.