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Digital dental radiography allows for exchange of images between primary and secondary care. However, it is common practice for radiographs to be printed out and attached to referrals. This study investigates the loss of diagnostic information of printed radiographs compared to the on-screen digital image. The best quality was achieved with images printed onto radiographic film or onto photographic paper with an inkjet printer. Laser and inkjet printer output onto 80 gsm office paper resulted in a loss of diagnostic information. Wherever possible, radiographs should be transmitted digitally between clinicians to maintain image integrity. Clinical Relevance: This paper illustrates the potential pitfalls of printing radiographs to be sent with referrals.

This study was undertaken to determine whether periosteum from different bone sources in a donor results in the same formation of bone and cartilage. In this case, periosteum obtained from the cranium and mandible (examples of tissue supporting intramembranous ossification) and the radius and ilium (examples of tissues supporting endochondral ossification) of individual calves was used to produce tissue-engineered constructs that were implanted in nude mice and then retrieved after 10 and 20 weeks. Specimens were compared in terms of their osteogenic and chondrogenic potential by radiography, histology, and gene expression levels. By 10 weeks of implantation and more so by 20 weeks, constructs with cranial periosteum had developed to the greatest extent, followed in order by ilium, radius, and mandible periosteum. All constructs, particularly with cranial tissue although minimally with mandibular periosteum, had mineralized by 10 weeks on radiography and stained for proteoglycans with safranin-O red (cranial tissue most intensely and mandibular tissue least intensely). Gene expression of type I collagen, type II collagen, runx2, and bone sialoprotein (BSP) was detectable on QRT-PCR for all specimens at 10 and 20 weeks. By 20 weeks, the relative gene levels were: type I collagen, ilium >> radial ≧ cranial ≧ mandibular; type II collagen, radial > ilium > cranial ≧ mandibular; runx2, cranial >>> radial > mandibular ≧ ilium; and BSP, ilium ≧ radial > cranial > mandibular. These data demonstrate that the osteogenic and chondrogenic capacity of the various constructs is not identical and depends on the periosteal source regardless of intramembranous or endochondral ossification. Based on these results, cranial and mandibular periosteal tissues appear to enhance bone formation most and least prominently, respectively. The appropriate periosteal choice for bone and cartilage tissue engineering and regeneration should be a function of its immediate application as well as other factors besides growth rate.

The aim of this study was to compare the accuracy of cephalometric measurements made with digital tracing software (FACAD) with equivalent hand-traced measurements, and to evaluate the reproducibility of each method. Pre- and post-surgical lateral cephalographs of 30 adult patients (12 males and 18 females, median age = 25 years, standard deviation = 8.7) who had undergone orthognathic treatment were scanned into a computer. One operator identified 25 landmarks digitally on the computer display and manually on acetate paper. Measurements on the 60 radiographs were duplicated, and measurement error of each method was determined with interclass correlation. A paired t-test was used to detect differences between the manual and digital methods. Overall, greater variability in digital cephalometric measurements was found. Differences in Gn', Li, Si, and Ii-Li measurements between the two methods were statistically (P < 0.05), but not clinically significant. The findings indicate that the results of the two investigated tracing methods are similar and that digital tracing with FACAD is reliable and can be used routinely.

Our study aimed to determine the accuracy of a low-cost, paper-based 3D printer by comparing a dry human mandible to its corresponding three-dimensional (3D) model using a 3D measuring arm. One dry human mandible and its corresponding printed model were evaluated. The model was produced using DICOM data from cone beam computed tomography. The data were imported into Maxilim software, wherein automatic segmentation was performed, and the STL file was saved. These data were subsequently analysed, repaired, cut and prepared for printing with netfabb software. These prepared data were used to create a paper-based model of a mandible with an MCor Matrix 300 printer. Seventy-six anatomical landmarks were chosen and measured 20 times on the mandible and the model using a MicroScribe G2X 3D measuring arm. The distances between all the selected landmarks were measured and compared. Only landmarks with a point inaccuracy less than 30% were used in further analyses. The mean absolute difference for the selected 2016 measurements was 0.36 ± 0.29 mm. The mean relative difference was 1.87 ± 3.14%; however, the measurement length significantly influenced the relative difference. The accuracy of the 3D model printed using the paper-based, low-cost 3D Matrix 300 printer was acceptable. The average error was no greater than that measured with other types of 3D printers. The mean relative difference should not be considered the best way to compare studies. The point inaccuracy methodology proposed in this study may be helpful in future studies concerned with evaluating the accuracy of 3D rapid prototyping models.

Bone biomechanical performance is a complex trait or, more properly, an ensemble of complex traits. Biomechanical performance incorporates flexibility under loading, yield and failure load, and energy to failure; all are important measures of bone function. To date, the vast majority of work has focused on yield and failure load and its surrogate, bone mineral density. We performed a reciprocal intercross of the mouse strains HcB-8 and HcB-23 to map and ultimately identify genes that contribute to differences in biomechanical performance. Mechanical testing was performed by 3-point bending of the femora. We measured femoral diaphysis cross-sectional anatomy from photographs of the fracture surfaces. We used beam equations to calculate material level mechanical properties. We performed a principal component (PC) analysis of normalized whole bone phenotypes (17 input traits). We measured distances separating mandibular landmarks from calibrated digital photographs and performed linkage analysis. Experiment-wide α = 0.05 significance thresholds were established by permutation testing. Three quantitative trait loci (QTLs) identified in these studies illustrate the advantages of the comprehensive phenotyping approach. A pleiotropic QTL on chromosome 4 affected multiple whole bone phenotypes with LOD scores as large as 17.5, encompassing size, cross-sectional ellipticity, stiffness, yield and failure load, and bone mineral density. This locus was linked to 3 of the PCs but unlinked to any of the tissue level phenotypes. From this pattern, we infer that the QTL operates by modulating the proliferative response to mechanical loading. On this basis, we successfully predicted that this locus also affects the length of a specific region of the mandible. A pleiotropic locus on chromosome 10 with LOD scores displays opposite effects on failure load and toughness with LOD scores of 4.5 and 5.5, respectively, so that the allele that increases failure load decreases toughness. A chromosome 19 QTL for PC2 with an LOD score of 4.8 was not detected with either the whole bone or tissue level phenotypes. We conclude that first, comprehensive, system-oriented phenotyping provides much information that could not be obtained by focusing on bone mineral density alone. Second, mechanical performance includes inherent trade-offs between strength and brittleness. Third, considering the aggregate phenotypic data allows prediction of novel QTLs.

Fibromodulin (Fmod) is a keratan sulfate small leucine-rich proteoglycan which is enriched in bones and teeth. In order to determine its functions on bone and tooth mineralization we characterized the phenotype of Fmod-deficient (Fmod-KO) mice using a new-generation microfocus computerized tomography system (micro-CT) and software allowing advanced visualization of 3-D data. Three-week-old and 10- week-old Fmod-KO mandibles and teeth were compared with those of age-matched wild-type (WT) mice. In both young and mature mice the Fmod-KO mandibles were hypomineralized, especially the posterior (proximal) part of the mandible as it appeared to be the main target of the molecule deficiency whereas less extensive alterations were found in the alveolar bone. In transverse sections, larger marrow spaces were observed in the Fmod-KO mice compared with age-matched young or mature WT mice. Quantitative evaluation of the pulp volume of the first molar and 3-D reconstructions suggested that dentinogenesis was diminished in 3-week-old Fmod-KO teeth. In contrast, increased dentin formation was found in 10-week-old Fmod-KO mice and it was accompanied by a reduced pulp volume. Thus, the differential effects of Fmod deficiency on bones and teeth appear to diverge in adult mice. This may result from the previously reported differences in the molecular weight of Fmod in the 2 tissues or from compensatory mechanisms due to the overexpression of DSP and DMP-1 in the dental pulp of Fmod-KO. It is also possible that a single molecule plays diverging roles in a tissue-specific or region-specific manner.

The enamel layerof kallikrein 4 (Klk4)-null mice has a normal thickness and a decussating pattern of enamel rods, but it contains residual enamel proteins, is less highly mineralized, and fractures in its deepest part just above the dentino-enamel junction (DEJ). The plane of fracture is puzzling because the deepest enamel is deposited earliest and, through the action of the secretory stage enamel protease (Mmp20), is the most mature part of the enamel layer at the time of the onset of Klk4 expression.To characterize the planes of fracture in Mmp20- and Klk4-null mice and to localize Klk4 expression in developing teeth.Klk4- and Mmp20-null mice were sacrificed at 7 weeks and their mandibular incisors were characterized by scanning electron microscopy. Klk4(+/)(lac)(Z) mice were mated with Klk4(+/)(lac)(Z) mice. Offspring were genotyped by polymerase chain reaction. Klk4(+/)(+), Klk4(+/)(lac)(Z), and Klk4(lac)(Z/)(lac)(Z) (null) littermates on postnatal days 5, 8, 11, and 14 were processed for β-galactosidase histochemistry.The enamel layer fractures at the DEJ in Mmp20-null mice, and fractures occur in enamel above the DEJ in Klk4-null mice. Klk4 is not expressed by secretory-stage ameloblasts, murine odontoblasts beneath the secretory stage, or maturation-stage ameloblasts. Klk4 is specifically expressed by transition and maturation-stage ameloblasts.The breakage of enamel near the DEJ in Klk4-null mice is not due to a failure of odontoblasts to express Klk4, but it relates to a progressive hypomineralization of enamel with depth.

Accurate evaluation of transverse mandibular dimension is a controversial and rarely addressed topic. Although mandibular narrowing via symphyseal osteotomy and bilateral ramus sagittal split was initially described more than 30 years ago, the development of a simple and effective clinical tool to assess the outcome of such procedures remains elusive. Although many quantitative modalities, such as frontal cephalogram, tomography, and interdental distance measurement, are in current use, each possesses significant liabilities. Prompted by a need for improved accuracy, simplicity, and reliability in the clinical setting, we developed and used a novel occlusographic analysis. The Madjidi occlusographic analysis does not rely on the position or tilt of moveable teeth; therefore, orthodontic changes do not influence quantification of mandibular position. Contours and mandibular relationships of interest are seen clearly, radiation is unnecessary, and occlusographic analysis can be quickly reproduced in the clinical setting using widely available materials. Although the evaluation of transverse mandibular dimension after surgical narrowing is frequently more controversial than accurate, the Madjidi occlusographic analysis is a reliably simple solution to an often complex problem.

Objective The aim of this study was to compare the accuracy of 3 modalities of digital panoramic radiographs—monitor-displayed images and printed copies on glossy paper and on blue transparent film—for assessment of position and morphology of mandibular third molars. Study design 164 third molars were recorded with one of 2 digital panoramic systems (Digora and Orthophos Plus) and assessed by 4 observers on 3 radiographic modalities: monitor display, glossy paper, and transparent film. The assessments were compared with surgeons' findings at the time of the operation (“gold standard”). Results Overall, the observer variation was larger than the variation between methods. A detailed paired analysis revealed some differences between the modalities for some diagnostic categories, but these were few and inconsistent. Conclusion Printed images from the Kodak 1200 ink-jet printer on glossy paper and blue transparent film may be as accurate as the original monitor-displayed digital panoramic images from the Digora and Orthophos Plus systems for assessment of position and morphology of mandibular third molars.

Digital panoramic radiographs may be viewed with computer monitors or archived as thermal or laser prints. To compare the available diagnostic information from thermal print images to that of corresponding computer monitor images, four calibrated evaluators performed a qualitative analysis of 13 specified anatomic features in 60 pairs of digital panoramic images presented in random order on a computer monitor and as thermal printed images. Each anatomic site was rated both for subjective diagnostic quality and diagnostic utility using a nominal scale. Computer monitor images more often were subjectively judged to have better quality. Within the parameters of this study, both formats had acceptable diagnostic utility for the majority of the anatomic features evaluated.

Accurate and repeatable methods for recording tooth contacts are required for the clinical management of problems related to occlusion. A thorough understanding of the materials and procedures used in these methods is important to achieve desirable results in the treatment of such problems. This study compared three occlusal examination methods to determine the influence of materials and procedures on the number of tooth contacts recorded. Tooth contacts were analyzed at two lateral mandibular positions with each method. It was found that the method that uses black silicone recorded the highest number of tooth contacts. Thus the most frequent type of occlusal pattern observed was full-balanced occlusion. This study suggested that the disparities of results reported in literature on occlusal contact patterns could be the result of the different materials and methods used for occlusal registration.