Rapid Bacterial Detection and Gram-Identification Using Bacterially Activated, Macrophage-Membrane-Coated Nanowired-Si Surfaces in a Microfluidic Device.

Bacterially induced sepsis requires rapid bacterial detection and identification. Hours count for critically ill septic patients, while current culture-based detection requires at least 10 h up to several days. Here, we apply a microfluidic device equipped with a bacterially activated, macrophage-membrane-coating on nanowired-Si adsorbent surfaces for rapid, bacterial detection and Gram-identification in bacterially contaminated blood. Perfusion of suspensions of Gram-negative or Gram-positive bacteria through a microfluidic device equipped with membrane-coated adsorbent surfaces detected low (<10 CFU/mL) bacterial levels. Subsequent, in situ fluorescence-staining yielded Gram-identification for guiding antibiotic selection. In mixed Escherichia coli and Staphylococcus aureus suspensions, Gram-negative and Gram-positive bacteria were detected in the same ratios as those fixed in suspension. Results were validated with a 100% correct score by blinded evaluation (two observers) of 15 human blood samples, spiked with widely different bacterial strains or combinations of strains, demonstrating the potential of the platform for rapid (1.5 h in total) diagnosis of bacterial sepsis.

Liposomes with Water as a pH-Responsive Functionality for Targeting of Acidic Tumor and Infection Sites.

A lipid named DCPA was synthesized under microwave-assisted heating. DCPA possesses a pyridine betaine, hydrophilic group that can be complexed with water through hydrogen bonding (DCPA-H2 O). DCPA-H2 O liposomes became protonated relatively fast already at pH<6.8, due to the high HOMO binding energy of DCPA-H2 O. In murine models, DCPA-H2 O liposomes had longer blood circulation times than natural DPPC or cationic DCPM liposomes, while after tail-vein injection DCPA-H2 O liposomes targeted faster to solid tumors and intra-abdominal infectious biofilms. Therapeutic efficacy in a murine, infected wound-healing model of tail-vein injected ciprofloxacin-loaded DCPA-H2 O liposomes exceeded the ones of clinically applied ciprofloxacin as well as of ciprofloxacin-loaded DPPC or DCPM liposomes.

Eradicating Infecting Bacteria while Maintaining Tissue Integration on Photothermal Nanoparticle-Coated Titanium Surfaces.

Photothermal nanoparticles locally release heat when irradiated by near-infrared (NIR). Clinical applications initially involved tumor treatment, but currently extend toward bacterial infection control. Applications toward much smaller, micrometer-sized bacterial infections, however, bear the risk of collateral damage by dissipating heat into tissues surrounding an infection site. This can become a complication when photothermal nanoparticle coatings are clinically applied on biomaterial surfaces requiring tissue integration, such as titanium-made, bone-anchored dental implants. Dental implants can fail due to infection in the pocket formed between the implant screw and the surrounding soft tissue ("peri-implantitis"). We address the hitherto neglected potential complication of collateral tissue damage by evaluating photothermal, polydopamine nanoparticle (PDA-NP) coatings on titanium surfaces in different coculture models. NIR irradiation of PDA-NP-coated (200 µg/cm2) titanium surfaces with adhering Staphylococcus aureus killed staphylococci within an irradiation time window of around 3 min. Alternatively, when covered with human gingival fibroblasts, this irradiation time window maintained surface coverage by fibroblasts. Contaminating staphylococci on PDA-NP-coated titanium surfaces, as can be per-operatively introduced, reduced surface coverage by fibroblasts, and this could be prevented by NIR irradiation for 5 min or longer prior to allowing fibroblasts to adhere and grow. Negative impacts of early postoperative staphylococcal challenges to an existing fibroblast layer covering a coated surface were maximally prevented by 3 min NIR irradiation. Longer irradiation times caused collateral fibroblast damage. Late postoperative staphylococcal challenges to a protective keratinocyte layer covering a fibroblast layer required 10 min NIR irradiation for adverting a staphylococcal challenge. This is longer than foreseen from monoculture studies because of additional heat uptake by the keratinocyte layer. Summarizing, photothermal treatment of biomaterial-associated infection requires precise timing of NIR irradiation to prevent collateral damage to tissues surrounding the infection site.

Polarization of Macrophages, Cellular Adhesion, and Spreading on Bacterially Contaminated Gold Nanoparticle-Coatings in Vitro.

Biomaterial-associated infections often arise from contaminating bacteria adhering to an implant surface that are introduced during surgical implantation and not effectively eradicated by antibiotic treatment. Whether or not infection develops from contaminating bacteria depends on an interplay between bacteria contaminating the biomaterial surface and tissue cells trying to integrate the surface with the aid of immune cells. The biomaterial surface plays a crucial role in defining the outcome of this race for the surface. Tissue integration is considered the best protection of a biomaterial implant against infectious bacteria. This paper aims to determine whether and how macrophages aid osteoblasts and human mesenchymal stem cells to adhere and spread over gold nanoparticle (GNP)-coatings with different hydrophilicity and roughness in the absence or presence of contaminating, adhering bacteria. All GNP-coatings had identical chemical surface composition, and water contact angles decreased with increasing roughness. Upon increasing the roughness of the GNP-coatings, the presence of contaminating Staphylococcus epidermidis in biculture with cells gradually decreased surface coverage by adhering and spreading cells, as in the absence of staphylococci. More virulent Staphylococcus aureus fully impeded cellular adhesion and spreading on smooth gold- or GNP-coatings, while Escherichia coli allowed minor cellular interaction. Murine macrophages in monoculture tended toward their pro-inflammatory "fighting" M1-phenotype on all coatings to combat the biomaterial, but in bicultures with contaminating, adhering bacteria, macrophages demonstrated Ym1 expression, indicative of polarization toward their anti-inflammatory "fix-and-repair" M2-phenotype. Damage repair of cells by macrophages improved cellular interactions on intermediately hydrophilic/rough (water contact angle 30 deg/surface roughness 118 nm) GNP-coatings in the presence of contaminating, adhering Gram-positive staphylococci but provided little aid in the presence of Gram-negative E. coli. Thus, the merits on GNP-coatings to influence the race for the surface and prevent biomaterial-associated infection critically depend on their hydrophilicity/roughness and the bacterial strain involved in contaminating the biomaterial surface.

Applications and Perspectives of Cascade Reactions in Bacterial Infection Control.

Cascade reactions integrate two or more reactions, of which each subsequent reaction can only start when the previous reaction step is completed. Employing natural substrates in the human body such as glucose and oxygen, cascade reactions can generate reactive oxygen species (ROS) to kill tumor cells, but cascade reactions may also have potential as a direly needed, novel bacterial infection-control strategy. ROS can disintegrate the EPS matrix of infectious biofilm, disrupt bacterial cell membranes, and damage intra-cellular DNA. Application of cascade reactions producing ROS as a new infection-control strategy is still in its infancy. The main advantages for infection-control cascade reactions include the fact that they are non-antibiotic based and induction of ROS resistance is unlikely. However, the amount of ROS generated is generally low and antimicrobial efficacies reported are still far <3-4 log units necessary for clinical efficacy. Increasing the amounts of ROS generated by adding more substrate bears the risk of collateral damage to tissue surrounding an infection site. Collateral tissue damage upon increasing substrate concentrations may be prevented by locally increasing substrate concentrations, for instance, using smart nanocarriers. Smart, pH-responsive nanocarriers can self-target and accumulate in infectious biofilms from the blood circulation to confine ROS production inside the biofilm to yield long-term presence of ROS, despite the short lifetime (nanoseconds) of individual ROS molecules. Increasing bacterial killing efficacies using cascade reaction components containing nanocarriers constitutes a first, major challenge in the development of infection-control cascade reactions. Nevertheless, their use in combination with clinical antibiotic treatment may already yield synergistic effects, but this remains to be established for cascade reactions. Furthermore, specific patient groups possessing elevated levels of endogenous substrate (for instance, diabetic or cancer patients) may benefit from the use of cascade reaction components containing nanocarriers.

Applications of 3D printing on craniofacial bone repair: A systematic review.

OBJECTIVES: Three-dimensional (3D) bioprinting, a method derived from additive manufacturing technology, is a recent and ongoing trend for the construction of 3D volumetric structures. The purpose of this systematic review is to summarize evidence from existing human and animal studies assessing the application of 3D printing on bone repair and regeneration in the craniofacial region. DATA & SOURCES: A rigorous search of all relevant clinical trials and case series was performed, based on specific inclusion and exclusion criteria. The search was conducted in all available electronic databases and sources, supplemented by a manual search, in December 2017. STUDY SELECTION: 43 articles (6 human and 37 animal studies) fulfilled the criteria. The human studies included totally 81 patients with craniofacial bone defects. Titanium or hydroxylapatite scaffolds were most commonly implanted. The follow-up period ranged between 6 and 24 months. Bone repair was reported successful in nearly every case, with minimal complications. Also, animal intervention studies used biomaterials and cells in various combination, offering insights into the techniques, through histological, biochemical, histomorphometric and microcomputed tomographic findings. The results in both humans and animals, though promising, are yet to be verified for clinical impact. CONCLUSIONS: Future research should be focused on well-designed clinical trials to confirm the short- and long- term efficacy of 3D printing strategies for craniofacial bone repair. CLINICAL SIGNIFICANCE: Emerging 3D printing technology opens a new era for tissue engineering. Humans and animals on application of 3D printing for craniofacial bone repair showed promising results which will lead clinicians to investigate more thoroughly alternative therapeutic methods for craniofacial bone defects.

MSX1 mutations and associated disease phenotypes: genotype-phenotype relations.

The Msx1 transcription factor is involved in multiple epithelial-mesenchymal interactions during vertebrate embryogenesis. It has pleiotropic effects in several tissues. In humans, MSX1 variants have been related to tooth agenesis, orofacial clefting, and nail dysplasia. We correlate all MSX1 disease causing variants to phenotypic features to shed light on this hitherto unclear association. MSX1 truncations cause more severe phenotypes than in-frame variants. Mutations in the homeodomain always cause tooth agenesis with or without other phenotypes while mutations outside the homeodomain are mostly associated with non-syndromic orofacial clefts. Downstream effects can be further explored by the edgetic perturbation model. This information provides new insights for genetic diagnosis and for further functional analysis of MSX1 variants.

Osteoblast integration of dental implant materials after challenge by sub-gingival pathogens: a co-culture study in vitro.

Sub-gingival anaerobic pathogens can colonize an implant surface to compromise osseointegration of dental implants once the soft tissue seal around the neck of an implant is broken. In vitro evaluations of implant materials are usually done in monoculture studies involving either tissue integration or bacterial colonization. Co-culture models, in which tissue cells and bacteria battle simultaneously for estate on an implant surface, have been demonstrated to provide a better in vitro mimic of the clinical situation. Here we aim to compare the surface coverage by U2OS osteoblasts cells prior to and after challenge by two anaerobic sub-gingival pathogens in a co-culture model on differently modified titanium (Ti), titanium-zirconium (TiZr) alloys and zirconia surfaces. Monoculture studies with either U2OS osteoblasts or bacteria were also carried out and indicated significant differences in biofilm formation between the implant materials, but interactions with U2OS osteoblasts were favourable on all materials. Adhering U2OS osteoblasts cells, however, were significantly more displaced from differently modified Ti surfaces by challenging sub-gingival pathogens than from TiZr alloys and zirconia variants. Combined with previous work employing a co-culture model consisting of human gingival fibroblasts and supra-gingival oral bacteria, results point to a different material selection to stimulate the formation of a soft tissue seal as compared to preservation of osseointegration under the unsterile conditions of the oral cavity.

In vivo biofilm formation on stainless steel bonded retainers during different oral health-care regimens.

Retention wires permanently bonded to the anterior teeth are used after orthodontic treatment to prevent the teeth from relapsing to pre-treatment positions. A disadvantage of bonded retainers is biofilm accumulation on the wires, which produces a higher incidence of gingival recession, increased pocket depth and bleeding on probing. This study compares in vivo biofilm formation on single-strand and multi-strand retention wires with different oral health-care regimens. Two-centimetre wires were placed in brackets that were bonded to the buccal side of the first molars and second premolars in the upper arches of 22 volunteers. Volunteers used a selected toothpaste with or without the additional use of a mouthrinse containing essential oils. Brushing was performed manually. Regimens were maintained for 1 week, after which the wires were removed and the oral biofilm was collected to quantify the number of organisms and their viability, determine the microbial composition and visualize the bacteria by electron microscopy. A 6-week washout period was employed between regimens. Biofilm formation was reduced on single-strand wires compared with multi-strand wires; bacteria were observed to adhere between the strands. The use of antibacterial toothpastes marginally reduced the amount of biofilm on both wire types, but significantly reduced the viability of the biofilm organisms. Additional use of the mouthrinse did not result in significant changes in biofilm amount or viability. However, major shifts in biofilm composition were induced by combining a stannous fluoride- or triclosan-containing toothpaste with the mouthrinse. These shifts can be tentatively attributed to small changes in bacterial cell surface hydrophobicity after the adsorption of the toothpaste components, which stimulate bacterial adhesion to the hydrophobic oil, as illustrated for a Streptococcus mutans strain.

Low-intensity pulsed ultrasound (LIPUS) and pulsed electromagnetic field (PEMF) treatments affect degeneration of cultured articular cartilage explants.

PURPOSE: Articular cartilage has some capacity for self-repair. Clinically used low-intensity pulsed ultrasound (LIPUS) and pulsed electromagnetic field (PEMF) treatments were compared in their potency to prevent degeneration using an explant model of porcine cartilage. METHODS: Explants of porcine cartilage and human osteoarthritic cartilage were cultured for four weeks and subjected to daily LIPUS or PEMF treatments. At one, two, three and four weeks follow-up explants were prepared for histological assessment or gene expression (porcine only). RESULTS: Non-treated porcine explants showed signs of atrophy of the superficial zone starting at one week. Treated explants did not. In LIPUS-treated explants cell clusters were observed. In PEMF-treated explants more hypertrophic-like changes were observed at later follow up. Newly synthesized tissue was present in treated explants. Gene expression profiles did indicate differences between the two methods. Both methods reduced expression of the aggrecan and collagen type II gene compared to the control. LIPUS treatment of human cartilage samples resulted in a reduction of degeneration according to Mankin scoring. PEMF treatment did not. CONCLUSIONS: LIPUS or PEMF prevented degenerative changes in pig knee cartilage explants. LIPUS reduced degeneration in human cartilage samples. LIPUS treatment seems to have more potency in the treatment of osteoarthritis than PEMF treatment.

Reliability and validity of measurements of facial swelling with a stereophotogrammetry optical three-dimensional scanner.

Volume changes in facial morphology can be assessed using the 3dMD DSP400 stereo-optical 3-dimensional scanner, which uses visible light and has a short scanning time. Its reliability and validity have not to our knowledge been investigated for the assessment of facial swelling. Our aim therefore was to assess them for measuring changes in facial contour, in vivo and in vitro. Twenty-four healthy volunteers with and without an artificial swelling of the cheek were scanned, twice in the morning and twice in the afternoon (in vivo measurements). A mannequin head was scanned 4 times with and without various externally applied artificial swellings (in vitro measurements). The changes in facial contour caused by the artificial swelling were measured as the change in volume of the cheek (with and without artificial swelling in place) using 3dMD Vultus software. In vivo and in vitro reliability expressed in intraclass correlations were 0.89 and 0.99, respectively. In vivo and in vitro repeatability coefficients were 5.9 and 1.3 ml, respectively. The scanner underestimated the volume by 1.2 ml (95% CI -0.9 to 3.4) in vivo and 0.2 ml (95% CI 0.02 to 0.4) in vitro. The 3dMD stereophotogrammetry scanner is a valid and reliable tool to measure volumetric changes in facial contour of more than 5.9 ml and for the assessment of facial swelling.

Surgically facilitated orthodontic treatment: a systematic review.

INTRODUCTION: Corticotomy and dental distraction have been proposed as effective and safe methods to shorten orthodontic treatment duration in adolescent and adult patients. A systematic review was performed to evaluate the evidence supporting these claims. METHODS: PubMed, Embase, and Cochrane databases were searched until April 2013 for randomized controlled trials, controlled clinical trials, and case series with 5 or more subjects that focused on velocity of tooth movement, reduction of treatment duration, or complications with various surgical protocols. There were no language restrictions during the search phase. Publications were systematically assessed for eligibility, and 2 observers graded the methodologic quality of the included studies with a predefined scoring system. RESULTS: Eighteen articles met the inclusion criteria. Seven studies were clinical trials, with small investigated groups. Only studies of moderate and low values of evidence were found. Surgically facilitated treatment was indicated for various clinical problems. All publications reported temporarily accelerated tooth movement after surgery. No deleterious effects on the periodontium, no vitality loss, and no severe root resorption were found in any studies. However, the level of evidence to support these findings is limited owing to shortcomings in research methodologies and small treated groups. No research concerning long-term stability could be included. CONCLUSIONS: Evidence based on the currently available studies of low-to-moderate quality showed that surgically facilitated orthodontics seems to be safe for the oral tissues and is characterized by a temporary phase of accelerated tooth movement. This can effectively shorten the duration of orthodontic treatment. However, to date, no prospective studies have compared overall treatment time and treatment outcome with those of a control group. Well-conducted, prospective research is still needed to draw valid conclusions.

Biofilm formation on stainless steel and gold wires for bonded retainers in vitro and in vivo and their susceptibility to oral antimicrobials.

OBJECTIVE: Bonded retainers are used in orthodontics to maintain treatment result. Retention wires are prone to biofilm formation and cause gingival recession, bleeding on probing and increased pocket depths near bonded retainers. In this study, we compare in vitro and in vivo biofilm formation on different wires used for bonded retainers and the susceptibility of in vitro biofilms to oral antimicrobials. MATERIALS AND METHODS: Orthodontic wires were exposed to saliva, and in vitro biofilm formation was evaluated using plate counting and live/dead staining, together with effects of exposure to toothpaste slurry alone or followed by antimicrobial mouthrinse application. Wires were also placed intra-orally for 72 h in human volunteers and undisturbed biofilm formation was compared by plate counting and live/dead staining, as well as by denaturing gradient gel electrophoresis for compositional differences in biofilms. RESULTS: Single-strand wires attracted only slightly less biofilm in vitro than multi-strand wires. Biofilms on stainless steel single-strand wires however, were much more susceptible to antimicrobials from toothpaste slurries and mouthrinses than on single-strand gold wires and biofilms on multi-strand wires. Also, in vivo significantly less biofilm was found on single-strand than on multi-strand wires. Microbial composition of biofilms was more dependent on the volunteer involved than on wire type. CONCLUSIONS: Biofilms on single-strand stainless steel wires attract less biofilm in vitro and are more susceptible to antimicrobials than on multi-strand wires. Also in vivo, single-strand wires attract less biofilm than multi-strand ones. CLINICAL SIGNIFICANCE: Use of single-strand wires is preferred over multi-strand wires, not because they attract less biofilm, but because biofilms on single-strand wires are not protected against antimicrobials as in crevices and niches as on multi-strand wires.

Application of cone beam computed tomography in facial imaging science.

The use of three-dimensional (3D) methods for facial imaging has increased significantly over the past years. Traditional 2D imaging has gradually being replaced by 3D images in different disciplines, particularly in the fields of orthodontics, maxillofacial surgery, plastic and reconstructive surgery, neurosurgery and forensic sciences. In most cases, 3D facial imaging overcomes the limitations of traditional 2D methods and provides the clinician with more accurate information regarding the soft-tissues and the underlying skeleton. The aim of this study was to review the types of imaging methods used for facial imaging. It is important to realize the difference between the types of 3D imaging methods as application and indications thereof may differ. Since 3D cone beam computed tomography (CBCT) imaging will play an increasingly important role in orthodontics and orthognathic surgery, special emphasis should be placed on discussing CBCT applications in facial evaluations.

Overexpression of osteoprotegerin promotes preosteoblast differentiation to mature osteoblasts.

OBJECTIVE: The hypothesis of the present study is that overexpression of osteoprotegerin (OPG) promotes preosteoblast maturation. MATERIALS AND METHODS: The preosteoblast cell line MC3T3-E1 was transfected with OPG overexpression. OPG expression was confirmed by enzyme-linked immunosorbent assay (ELISA) and Western blot. Changes in the transcription factors in OPG-expressing cells were assessed by real-time polymerase quantitative polymerase chain reaction (RT-qPCR). Alkaline phosphate (ALP) expression was measured by ELISA. RESULTS: The success of stable transfection of MC3T3-E1 cells with OPG overexpression was confirmed by MoFlow sorting followed by G418 selection. RT-qPCR showed that expression of RunX2, the most important osteoblast differentiation controlling factor, was suppressed. Smad1 and Akt1, as well as ALP, were upregulated in the OPG overexpressing cells. CONCLUSION: Results from the present study provide evidence that overexpression of OPG in preosteoblasts promotes its differentiation into mature osteoblasts.

Craniofacial morphological characteristics of Chinese adults with normal occlusion and different skeletal divergence.

The aim of the present study was to examine the craniofacial morphologic characteristics of different vertical dysplasias in a population of Chinese adults with normal occlusion. Sixty-nine subjects (39 males and 30 females) were selected from 800 healthy students between 18 and 24 years of age. Lateral cephalograms were obtained and 27 hard and 10 soft tissue measurements were analysed. The subjects were then divided into three groups: high angle, low angle, or control according to the value of FH-MP. Intraclass correlation coefficient was determined for the repeated measurements. One-way analysis of variance was used to determine the differences between the groups. The results showed that the low-angle group had a larger cranial basis angle (N-S-Ar) and the high-angle group had a shorter maxilla (Ans-Ptm; P < 0.01). The high-angle group displayed vertical hyperdivergency with increased PP-OP, OP-MP, gonial, and lower gonial angles, whereas the low-angle group showed significant hypodivergence with decreased values for all variables (P < 0.01). The low-angle group displayed a more protrusive chin and the high-angle group a more retrusive chin (P < 0.01). Differences in dentoalveolar measurements in the divergent groups were mainly in the anterior region. Moreover, the low-angle group had a thicker and the high-angle group a thinner lower dentoalveolus (P < 0.01). For face height measurements, the main differences in the divergent groups were at the anterior lower third (P < 0.01). Soft tissue deviations were less obvious in the high-angle group and in general less significant than those of the hard tissues in both divergent groups. Significantly different morphological characteristics exist in Chinese adults with vertical dysplasia but normal occlusion. Major skeletal cephalometric changes were found for the lower facial third. The soft tissues showed a well-adapting mechanism of soft tissue coverage for the skeletal dysplasia.

The role of collagen receptors Endo180 and DDR-2 in the foreign body reaction against non-crosslinked collagen and gelatin.

Despite the use of collagen-derived scaffolds in regenerative medicine, little is known about the degradation mechanisms of these scaffolds in vivo. Non-crosslinked dermal sheep (NDSC) and gelatin disks were implanted subcutaneously in mice. NDSC disks showed a very low degradation rate, despite the presence of high numbers of macrophages and the influx of neutrophils. This was attributed to the presence of the matrix metalloproteinase inhibitor TIMP-1. The limited degradation occurred mainly in the later stages of the foreign body reaction, and could be attributed to (1) phagocytosis by macrophages due to a co-expression of Endo180 and MT1-MMP on these cells (intracellular degradation) and (2) the presence of MMP-13 due to an upregulation of the expression of the DDR-2 receptor (extracellular degradation). In contrast, gelatin disks degraded quickly, due to the efficient formation of large giant cells as well as the presence of MMP-13; the inhibitor TIMP-1 was absent. The DDR-2 receptor was not expressed in the gelatin disks. Endo180 and MT1-MMP were expressed, but at most times no co-expression was seen. We conclude that the physical state of collagen (native or denatured) had a dramatic outcome on the degradation rate and provoked a completely different foreign body reaction.

Comparison between two-dimensional and midsagittal three-dimensional cephalometric measurements of dry human skulls.

The aim of this study was to compare two- and three-dimensional cephalometric values by using a three-dimensional analysis based on the midsagittal plane. Spherical metal markers were fixed on to the anatomical landmarks of 10 human skulls, which were examined radiographically with conventional lateral cephalograms and cone-beam computed tomographic (CBCT) scans. Preprogrammed analyses calculated the 18 angular and linear two- and three-dimensional cephalometric values. An error study was made to assess the accuracy and reliability of the methods used. Both sets of values were compared using Wilcoxon's signed-rank test. Probabilities of less than 0.05 were accepted as significant. Reliability of the measurements was assessed by intraclass correlation coefficients (ICC) based on absolute agreement. The method error (ME) was tiny (mean ME<0.61 measuring unit) and reliable (ICC>0.97). Comparison of the two- and three-dimensional measurements showed that that they were reliable (ICC>0.88) and that there were no significant differences (P=0.41-1.00). The values from the cephalometric analyses were comparable and interchangeable when using the midsagittal three-dimensional approach as described.

Accuracy and reliability of facial soft tissue depth measurements using cone beam computer tomography.

It is important to have accurate and reliable measurements of soft tissue thickness for specific landmarks of the face and scalp when producing a facial reconstruction. In the past several methods have been created to measure facial soft tissue thickness (FSTT) in cadavers and in the living. The conventional spiral CT is mostly used to determine the FSTT but is associated with high radiation doses. The cone beam CT (CBCT) is a relatively new computer tomography system that focuses on head and neck regions and has much lower radiation doses. The aim of this study is to determine the accuracy and reliability of CBCT scans to measure the soft tissue thicknesses of the face. Seven cadaver heads were used. Eleven soft tissue landmarks were identified on each head and a punch hole was made on each landmark using a dermal biopsy punch. The seven cadaver heads were scanned in the CBCT with 0.3 and 0.4mm resolution. The FSTT at the 11 different sites (soft tissue landmarks) were measured using SimPlant-ortho volumetric software. These measurements were compared to the physical measurements. Statistical analysis for the reliability was done by means of the interclass coefficient (ICC) and the accuracy by means of the absolute error (AE) and absolute percentage error (APE). The intra-observer (0.976-0.999) and inter-observer (0.982-0.997) correlations of the CBCT and physical measurements were very high. There was no clinical significant difference between the measurements made on the CBCT images and the physical measurements. Increasing the voxel size from 0.4 to 0.3mm resulted in a slight increase of accuracy. Cone beam CT images of the face using routine scanning protocols are reliable for measuring soft tissue thickness in the facial region and give a good representation of the facial soft tissues. For more accurate data collection the 0.3mm voxel size should be considered.

Comparison of low-intensity pulsed ultrasound and pulsed electromagnetic field treatments on OPG and RANKL expression in human osteoblast-like cells.

OBJECTIVE: To compare two clinically applied treatments to stimulate bone healing-low-intensity pulsed ultrasound (LIPUS) and pulsed electromagnetic field (PEMF)-for their effects on RANKL and OPG expression in osteoblast-like cells in vitro. MATERIALS AND METHODS: LIPUS or PEMF was applied to Saos-2 cells for 10 minutes or 3 hours. RANKL and OPG expressions were analyzed at 0, 4, 8, or 12 hours after treatment with real-time PCR. Secreted protein levels in culture supernatant were analyzed at the same posttreatment time points using specific ELISA assays. RESULTS: Neither LIPUS nor PEMF had an effect on RANKL protein expression. OPG protein was significantly increased by LIPUS after 0 and 4 hours (brief short-term effect) and was increased almost 2.5-fold by PEMF after 8 hours. The mRNA levels of OPG and RANKL were hardly affected by LIPUS treatment at any time point. PEMF induced a fivefold increase in RANKL mRNA expression at t = 0. A brief PEMF treatment of 10 minutes resulted in downregulation of RANKL expression after 0 and 4 hours and upregulation at 12 hours. OPG mRNA was downregulated after 8 hours. CONCLUSION: The effects of LIPUS or PEMF expression on OPG and RANKL are limited. From our experiments, it seems that LIPUS treatment resulted in a quick protein response, while the response of cells to PEMF (3 hours) was delayed. The increase in OPG protein at 8 hours post PEMF treatment is indicative of reduction of osteolysis.