Plasma-arc generated light inhibits proliferation and induces apoptosis of human gingival fibroblasts in a dose-dependent manner.

OBJECTIVE: This study examined the effects of blue light exposure on the proliferation and cytotoxicity of human gingival fibroblasts (HGF). Cellular mechanism by which blue light causes cytotoxic effects was also investigated. METHODS: HGF were exposed to the plasma-arc generated blue light with various energy densities ranging from 2 to 48J/cm(2). After light exposure of the cells, they were processed for analyzing tritium incorporation, succinate dehydrogenase (SDH) activity, trypan blue exclusion, and DNA fragmentation. In addition, possible mechanism of the light-mediated cytotoxicity was investigated through flow cytometric and Western blot analyses. RESULTS: Blue light exposure significantly inhibited proliferation and SDH activity of HGF in a dose-dependent manner; exposure more than 12J/cm(2) had a toxic effect on the cells. The blue light-induced cytotoxicity of the cells resulted from apoptosis, as proven by the migration of many cells to the sub-G(1) phase of cell cycle and the appearance of DNA ladders. Additional experiments revealed that blue light induces apoptosis of HGF through mitochondrial stress and poly (ADP ribose) polymerase cleavage. SIGNIFICANCE: This study suggests that plasma-arc generated blue light exerts some harm to cells, particularly damaging effect to DNA, and thus a long curing time more than recommended can cause biological damage on the oral tissue.     

CASE STUDIES for Dentistry: development of a tool to author interactive, multimedia, computer-based patient simulations

Computer-based patient simulations have been used to enhance the dental curriculum since the 1980s. This article describes the development of CASE STUDIES for Dentistry (CSD), a patient case simulation building template, developed at Virginia Commonwealth University, with which authors who have no programming expertise can create realistic, effective, interactive multimedia patient simulations by entering their own information and images into a straightforward, fill in the blanks interface. This program was written with Authorware, by Macromedia Inc. Design considerations included emphasis on information collection and analysis, synthesis of collected information, hypothesis proposal and testing, diagnosis, and treatment planning. The program consists of easily accessible interfaces for both authors and students. Authors build simulated patients using typed-in text and their own images. Faculty can build computer-based simulated patients so that students can immediately practice what they learn in class within a simulated doctor-patient relationship. CSD allows building simulations ranging from simple to complex patients in multiple disciplines. Robust feedback and other features allow students to learn both process and content in a self-directed, interactive environment.     

Automatic hole repairing for cranioplasty using Bézier surface approximation

Cranioplasty is the procedure that repairs holes or defects in the skull with cranial implants. When the bone from the hole is missing, damaged, or infected, the defect needs to be covered with an artificial plate to protect the brain. In this study, a hole-repairing algorithm is developed to aid shaping artificial plates for cranioplasty by describing a method for filling holes in defective biomodels with unstructured triangular surface meshes or in stereolithography format. The resulting patching meshes interpolate the shape and density of the surrounding mesh. The steps in repairing a hole include hole identification, hole triangulations using genetic algorithm (GA) optimization, and a customized advancing-front meshing technique using surface approximations based on a Quartic Bézier Gregory patch.     

Hypohyperdontia: literature review and report of seven cases

Hypodontia in combination with hyperdontia (hypohyperdontia) is a condition of mixed numeric variation in the human dentition. A comprehensive review on the hypohyperdontia literatures reported prevalence ranges from 0.002% to 3.1%. Our seven cases of hypohyperdontia involved both the maxillary and the mandibular arches. A traditional narrative review is included to describe the prevalence, etiology, and previously reported cases on hypohyperdontia. Furthermore, we opine that comprehensive clinical and radiographic examinations are essential for recognizing such rare dental anomalies. Judicious use of radiographs not only enhances the detection of hypohyperdontia, but also leads to changes in the course of management.     

A newly designed resonance frequency analysis device for dental implant stability detection

Resonance frequency (RF) analysis technology was used to design a new dental implant stability detector. To calibrate and test the performance of this novel apparatus, in vitro and in vivo models, respectively, were used. The RF values of the test implants detected using our new device and a commercially available analogous device (Osstell) were compared. Further, implant stability status was also detected clinically using our device at 2, 4, 8, and 12 weeks after surgery. A high correlation was demonstrated between the values measured with the two devices (y = 0.31x-12.45; R2 = 0.98, p < 0.05). In our clinical tests, an initial RF value above 10.0 kHz indicated that the implant was ready to accept functional loading, while values in the 4.0-10.0 kHz range reflected the need for further osseointegration. In conclusion, these results indicated that our new device might be useful in a clinical setting for evaluating the healing status of a placed implant.     

Immunoglobulins in milk from cows immunized with oral strains of Actinomyces, Prevotella, Porphyromonas, and Fusobacterium.

Immunization of pregnant cows with bacteria leads to the presence of high concentrations of specific antibodies in colostrum and milk. A total of 14 cows was immunized with single strains of heat-killed oral bacteria or pools of strains of Actinomyces, Porphyromonas, Prevotella, and Fusobacterium. Two cows were treated with adjuvant alone. The mean percentages of IgG1, IgG2, IgM, and IgA in all of the milks were 83.8, 3.8, 9.3, and 3.1, respectively. ELISA and whole cell agglutination assays demonstrated high titers in the milks from the cows immunized with either individual strains or the bacterial pools. The highest titers determined by ELISA belonged to the IgG1 isotype and in several milks were 64-fold greater than titers in milk from cows treated with adjuvant alone. The concentrations of all antibodies and the titers determined by ELISA and whole cell agglutination assays markedly decreased from the first to the sixth milkings. The functional specificity of the antibodies was demonstrated by agglutination tests against a wide range of bacteria including members of Actinomyces, Fusobacterium, Porphyromonas, Prevotella, Streptococcus, Eubacterium, Propionibacterium, Peptostreptococcus, Bacteroides, Actinobacillus, Haemophilus, Capnocytophaga, and Wolinella. Minimal cross-reactions with bacteria in other genera were observed with all of the milks. High-titer milk preparations have been obtained from immunized cows, and the capacity of the bovine antibodies to agglutinate target bacteria indicates their potential usefulness in oral passive immunization studies.     

Progressive dysphagia in an elderly male

Dysphagia can result from a variety of causes, including central nervous and peripheral nervous system, myogenic, and structural disorders. A 76-year-old man underwent anterior cervical disketomy and fusion 10 years ago, with progressive dysphagia noted 2 years ago. Endoscopy showed an oropharyngeal tumor, and lateral plain film evaluation of the neck revealed a cervical plate extrusion. Removal of the instrumentation and tumor with primary closure of the pharyngeal perforation was performed, and dysphagia was resolved postoperatively. We report the case of an unusual presentation in the pharynx. We should not neglect this rare diagnosis, because it can progress to a life-threatening outcome.     

Assessing the relationship between children's oral health status and that of their mothers

BackgroundThe authors conducted a study to describe the relationship between the oral health of young children and that of their mothers.MethodsUsing data from the Third National Health and Nutrition Examination Survey and a related birth certificate–linked file, the authors compiled a sample of 1,184 mother/child pairs for children aged 2 through 6 years. The authors performed logistic and cumulative logistic regression analyses by using children's caries experience and untreated caries status as dependent variables. They evaluated the mothers' untreated caries status and tooth loss status along with other covariates, including age, race/ethnicity and poverty status.ResultsChildren of mothers who had high levels of untreated caries were more than three times as likely (odds ratio [OR], 3.5; 95 percent confidence interval [CI], 2.0–6.2) to have higher levels of caries experience (treated or untreated dental caries) compared with children whose mothers had no untreated caries. A similar relationship was observed between mothers' tooth loss and caries experience among their children. The children of mothers with high levels of tooth loss were more than three times as likely (OR, 3.3; 95 percent CI, 1.8–6.4) to have higher levels of caries experience compared with children of mothers with no tooth loss; for mothers with moderate tooth loss, the OR was 2.3 (95 percent CI, 1.5–3.5).ConclusionsMothers' oral health status is a strong predictor of the oral health status of their children.Practice ImplicationsPreventive plans for children should be based on a caries risk assessment. The results of this study demonstrate that basic information obtained from the child's mother regarding her oral health status is valuable in helping the dentist determine the child's caries risk.     

Repeated oral hygiene instructions alone, or in combination with metronidazole dental gel with or without subgingival scaling in adult periodontitis patients: a one-year clinical study

The aims of the present study were to evaluate the clinical efficacy of, and to monitor microbiologically, repeated oral hygiene instructions alone or in combination with metronidazole 25% gel or subgingival scaling with or without metronidazole gel in treatment of new, residual or recurrent periodontal pockets in previously treated adult periodontitis patients. Ten suitable patients were included in this randomized single-blind clinical study with an intra-individual design. Clinical parameters were measured before and at 1, 3, 6, 9 and 12 months after treatment. Subgingival plaque samples were taken at every examination from one selected site in each quadrant. Smears from plaque samples were silver-stained and differential counting was performed under light microscopy at 1000X magnification. Four treatment modalities: (i) oral hygiene instruction (OHI) alone; (ii) OHI and metronidazole dental gel; (iii) OHI and subgingival scaling; (iv) OHI and subgingival scaling plus metronidazole gel, were randomly assigned to one quadrant of each patient. At the 12-month examination, the mean reductions in probing pocket depth were 2.6 mm after OHI alone, 2.8 mm after OHI and metronidazole gel, 3.3 mm after OHI and subgingival scaling and 2.6 mm after oral OHI and subgingival scaling plus metronidazole gel. The mean gains in probing attachment level were 2.2 mm, 1.9 mm, 2.7 mm and 1.6 mm, respectively. Although there were statistically significant differences in treatment responses between some treatment modalities at some time points, these were not considered to be clinically significant. Differential counts showed a shift towards a healthy microflora in response to all treatment modalities. From the 12-month results, it was concluded that the metronidazole 25% gel produced positive effects on the clinical parameters and on the subgingival plaque microbiological composition in new, residual or recurrent pockets in previously treated chronic periodontitis patients. However, the metronidazole gel alone or in combination with scaling does not seem to have any additional clinically significant therapeutic effects over and above those derived from improved oral hygiene resulting from monthly recalls, with or without subgingival scaling.