Myofascial pain and toothaches

Despite improved understanding of orofacial pain in recent years, accurate diagnosis of pain is still challenging in modern dentistry. Many disorders in the head and neck region are known to refer pain to dental structures and imitate dental pain. Due to the location of the perceived pain dental clinicians are often involved in the diagnosis and management of the pain. Myofascial pain (MFP) is widely believed to be the most frequently occurring orofacial pain of non-odontogenic origin. It has long been known that MFP could mimic pulpitic symptoms. Past studies have shown that MFP is a relatively prevalent condition among the general population and the one that is most often misdiagnosed by dentists. Despite its prevalence and the potential for misdiagnosis, there has been little investigation into this old problem, and information about myofascial pain remains fragmented and poorly understood. In this article some of the features associated with myofascial pain will be highlighted. The inter-relationship between myofascial pain and toothaches will also be examined and suggestions made in the areas of diagnosis and management of the condition. It is hoped that dental clinicians will be able to differentiate and manage the conditions effectively when dealing with them in the future.     

Using extracted teeth for research: the effect of storage medium and sterilization on dentin bond strengths

BACKGROUND: The Centers for Disease Control and Prevention has adopted guidelines for infection control of extracted teeth used for research and teaching, requiring that teeth be sterilized before use. The authors conducted a study to test the null hypothesis that the storage medium and sterilization method have no effect on composite-to-dentin bond strengths. MATERIALS AND METHODS: The authors collected 170 bovine incisors, cleaned them and placed them randomly into one of six storage media at 37 degrees C for 60 days: distilled water (dH(2)O), 0.9 percent sodium chloride, 0.5 percent chloramine-T, 5.25 percent sodium hypochlorite (NaClO), 2 percent glutaraldehyde and 10 percent formalin. For sterilization, they autoclaved a subset of 10 specimens from every sample, while they stored another subset of 10 specimens from every sample (except for the 10 percent formalin sample) in 10 percent formalin for 14 days. The authors then embedded the specimens in epoxy and ground flat the facial surface to expose middle-depth dentin, which they polished to 600 grit. They used a dental adhesive to apply composite to the exposed dentin. The authors tested the composite-to-dentin shear bond strength 24 hours after bonding. They analyzed the data using global analysis of variance and, when appropriate, multiple post hoc tests (P = .05). RESULTS: Storage in NaClO resulted in significantly lower bond strength than that of the other treatment specimens. Sterilization with the autoclave negatively affected the bond strength of specimens stored initially in dH(2)O or 10 percent formalin, while sterilization with formalin alone had no significant effect on bond strengths. CONCLUSIONS: Storing bovine teeth in 5.25 percent NaClO may negatively affect composite-to-dentin bond strengths. Immersion in 10 percent formalin might be the best option for storage and sterilization of bovine teeth that are to be used in dental bonding studies in vitro.     

Effect of bisphosphonates on anodized and heat-treated titanium surfaces: an animal experimental study

Background: Recent investigations reported that osseointegration of titanium implants can be significantly reinforced with a nanostructure treated with anodic oxidation and heat treatment. This experimental study investigates the effect of bisphosphonates on the nanotubular implant surface in rats. Methods: Thirty‐six titanium implants were divided into three groups: 1) machine‐turned (MT), 2) anodized and heat‐treated (AH), and 3) anodized and heat‐ and bisphosphonate‐treated (AHB) groups. The 36 implants were randomly placed in both tibias of 18 male Wistar rats. After 2 and 4 weeks, the levels of osseointegration of the implants were evaluated by a removal torque test and microcomputerized tomography (μCT). Peri‐implant bone tissue on the extracted region was examined for the expression of type I collagen and osteocalcin. Results: The AHB group showed the highest removal torque at 2 and 4 weeks (13.92 ± 1.51 Ncm and 18.10 ± 2.15 Ncm, respectively) followed, in order, by the AH group (11.63 ± 1.58 Ncm at 2 weeks and 14.80 ± 2.34 Ncm at 4 weeks) and MT group (4.30 ± 0.76 Ncm at 2 weeks and 6.20 ± 1.33 Ncm at 4 weeks) with statistically significant differences between the MT and other two groups at both time points. μCT images also revealed a denser appearance around implants in the AHB group than in the other groups. Levels of type I collagen and osteocalcin expression were similar between the MT and AH groups; however, the values were significantly higher in the AHB group compared to the other groups, which were 220.85% ± 71.09% and 363.04% ± 100.21%, respectively (P <0.05). Conclusion: Within the limits of this experiment, it was concluded that surface loading with bisphosphonates significantly improved the degree of osseointegration of titanium implants with a nanostructure.     

Mechanical properties of computer-aided design/computer-aided manufacturing resin composites assuming perfect silane coupling using in silico homogenization of cryo-electron microscopy images

Purpose

The aim of this study was to determine the mechanical properties of computer-aided design/computer-aided manufacturing (CAD/CAM) resin composites for dental restoration assuming perfect silane coupling by in silico homogenization analysis using a three-dimensional model constructed from cryo-electron microscopy (cryo-EM) images.

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.