Using Intraoral Scanning Technology for Three-Dimensional Printing of Kennedy Class I Removable Partial Denture Metal Framework: A Clinical Report.

Removable partial dentures (RPDs) are used to restore missing teeth and are traditionally fabricated using the lost-wax casting technique. The casting process is arduous, time-consuming, and requires a skilled technician. The development of intraoral scanning and 3D printing technology has made rapid prototyping of the RPD more achievable. This article reports a completed case of direct fabrication of a maxillary RPD metal framework (Kennedy Class I) using intraoral scanning and 3D printing techniques. Acceptable fit and satisfactory clinical outcome were demonstrated. Intraoral scanning and 3D printing for fabrication of the RPD metal framework is a useful alternative to conventional impression and casting techniques, especially for patients suffering from nasal obstruction or intolerance.

Soft tissue image reconstruction using cone-beam computed tomography combined with laser scanning: a novel method to evaluate the masticatory mucosa.

OBJECTIVE: To construct a 3-D model of the masticatory mucosa to measure the thickness of the facial/lingual gingiva and palatal mucosa. STUDY DESIGN: Maxillofacial regions of 8 volunteers were scanned using cone-beam computed tomography to generate 3-D maxillary and mandibular models. Digital models were obtained by laser scanning of the impressions. Models were constructed using global data registration and Boolean subtraction. Accuracy was assessed by comparison against control patients with a periodontal pack around their gingival boundaries. Inter- and intra-observer variability were determined. RESULTS: Masticatory mucosa models (in stereolithography format) showed the gingival and mucosal contours. The gingival thickness of the 3-D models and controls were not significantly different (P > .05). The interclass correlation coefficient and Kappa values indicated good intra-observer and inter-observer agreement, respectively. CONCLUSIONS: Cone-beam computed tomography combined with laser scanning can be reliable for visualizing and measuring the thickness of the masticatory mucosa.

Prospects application of polypyrrole-based immunosensor to Porphyromonas gingivalis quantification in subgingival plaque samples.

BACKGROUND: Periodontitis still poses a serious threat to oral and systemic health condition of humans. The proportion of the main pathogenic bacteria change in localized sites was associated with the initiation of the disease process. However, the limitations of microbiological diagnostic aids rendered the diagnosis of active periodontitis status point-of-care or chair-side based on microbiological data difficult. METHODS: Porphyromonas gingivalis, a major putative etiological agent in the initiation and progression of chronic periodontitis, was used as the experimental subject. An immunosensor based on polypyrrole-coated interdigitated array microelectrodes was developed to quantify Porphyromonas gingivalis in pure culture, gingival crevicular fluid and saliva samples. The regression equation for the normalized impedance change (NIC) versus Porphyromonas gingivalis concentration (C) was measured. The correlation between results of the immunosensor and quantitative real-time PCR method in quantifying Porphyromonas gingivalis in subgingival plaque samples was evaluated. RESULTS: Results of the study revealed that the lowest detection limits of the immunosensor was 1.9 x 10(4), 2.7 x 10(5), and 2.7 x 10(6) cells/mL in pure culture, gingival crevicular fluid, and saliva samples respectively. The values determined using the immunosensor strongly correlated with those obtained using quantitative real-time PCR method (R2 = 0.91, p < 0.05). The immunosensor did not require any labels and amplification steps, and the total detection time from sampling to measurement was less than one hour. CONCLUSIONS: The immunosensor developed in the present study offered some insight into monitoring the change in the number of periodontal bacteria chair-side during routine clinical practice.

Response of human periodontal ligament cells to baicalin.

BACKGROUND: Periodontitis is the most common cause of tooth loss in adults. Periodontal ligament cell (PLC)-based therapy is considered one of the most promising methods in periodontal tissue regeneration. The traditional Chinese medicine baicalin has been shown to possess antimicrobial and anti-inflammatory activities and enhance cell proliferation and alkaline phosphatase activity. The aim of this study is to investigate the response of human PLCs (HPLCs) to baicalin. METHODS: The effect of baicalin on cultured HPLC proliferation was measured with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The effect of baicalin on the expression of osteoprotegerin (OPG), receptor activator of nuclear factor-κB ligand (RANKL), core binding factor α1 (Cbfα1), and osteocalcin (OC) was determined by quantitative real-time polymerase chain reaction and immunodetection. RESULTS: Baicalin at a concentration of 0.01 µg/mL promoted HPLC proliferation, upregulated OPG messenger RNA (mRNA) and protein expression, and downregulated RANKL mRNA and protein expression. In addition to reducing the RANKL/OPG expression ratio significantly, it also increased Cbfα1 and OC mRNA and protein expression. CONCLUSION: Baicalin showed multifaceted regulation of genes with important roles in tissue growth and differentiation, and thus it has the potential to be a promising candidate for HPLC-based periodontal regeneration therapy.

Effect of icariin on cell proliferation and the expression of bone resorption/formation-related markers in human periodontal ligament cells.

Periodontitis is a common destructive inflammatory disease that leads to changes in the tooth-supporting tissues. Human periodontal ligament cells are essential in periodontal tissue regeneration. The traditional Chinese medicine icariin promoted bone formation, stimulated the osteogenic differentiation of preosteoblastic cells and inhibited osteoclast differentiation and bone resorption. Thus, in the present study, the effect of icariin on cell proliferation and the expression of osteoprotegerin (OPG), receptor activator of nuclear factor-κB ligand (RANKL), core binding factor α1 (Cbfa1) and osteocalcin (OC) was investigated in human periodontal ligament cells, by an MTT assay, qPCR and western blot analysis. The results demonstrated that icariin promoted cell proliferation in a dose- and time-dependent manner, upregulated OPG, Cbfa1 and OC expression, and downregulated RANKL production and the RANKL/OPG expression ratio. This suggested the potential value of icariin in treating alveolar bone resorption and promoting periodontal tissue regeneration, due to its ability to stimulate the proliferation and osteogenic differentiation of human periodontal ligament cells and inhibit osteoclast differentiation.

Phenotypic changes in nonfimbriated smooth strains of Aggregatibacter actinomycetemcomitans grown in low-humidity solid medium.

Aggregatibacter actinomycetemcomitans is the primary etiologic agent of localized aggressive periodontitis. In vitro, it can undergo fimbriated rough to nonfimbriated smooth phenotypic transition, accompanied by an increase in invasive ability and a decrease in adhesive ability. No opposite direction phenotypic transition was reported. To better understand its pathogenicity, the authors studied the morphological changes of nonfimbriated smooth strains induced by growth environmental humidity. Transmission electron microscopy was used to identify fimbriae expression change. It was found that the lower medium humidity, the more fimbriae reexpressed. In conclusion, the smooth strain of A. actinomycetemcomitans can reexpress the fimbriae in lower humidity environment.

Detection of bacterial cells by impedance spectra via fluidic electrodes in a microfluidic device.

In this study, a novel method for detecting bacterial cells in deionized (DI) water suspension is presented by using fluidic electrodes with a hydrodynamic focusing technique. KCl solution was utilized as both sheath flow and fluidic electrodes, and the bacterial suspension was squeezed to form three flowing layers with different conductivities on a microfluidic chip. An impedance analyzer was connected with the KCl solution through two Ag/AgCl wires to apply an AC voltage to fluidic layers within a certain frequency for impedance measurements. Porphyromonas gingivalis and Escherichia coli were detected and linear relationships were found between the impedance and the logarithmic value of the bacterial concentration in certain cell concentration ranges. It is demonstrated that bacterial detection using the microdevice is rapid and convenient, with a chip made of simple flow channels, and the detection sensitivity of cell counting can be tuned by varying the width of the sample flow layer through changing input velocities, showing a detection limit of 10(3) cells mL(-1).