Buccal Bone Plate Remodeling After Immediate Implant Placement With and Without Synthetic Bone Grafting and Flapless Surgery: Radiographic Study in Dogs

Recent studies in animals have shown pronounced resorption of the buccal bone plate after immediate implantation. The use of flapless surgical procedures prior to the installation of immediate implants, as well as the use of synthetic bone graft in the gaps represent viable alternatives to minimize buccal bone resorption and to favor osseointegration. The aim of this study was to evaluate the healing of the buccal bone plate following immediate implantation using the flapless approach, and to compare this process with sites in which a synthetic bone graft was or was not inserted into the gap between the implant and the buccal bone plate. Lower bicuspids from 8 dogs were bilaterally extracted without the use of flaps, and 4 implants were installed in the alveoli in each side of the mandible and were positioned 2.0 mm from the buccal bone plate (gap). Four groups were devised: 2.0-mm subcrestal implants (3.3 x 8 mm) using bone grafts (SCTG), 2.0-mm subcrestal implants without bone grafts (SCCG), equicrestal implants (3.3 x 10 mm) with bone grafts (EGG), and equicrestal implants without bone grafts (ECCG). One week following the surgical procedures, metallic prostheses were installed, and within 12 weeks the dogs were sacrificed. The blocks containing the individual implants were turned sideways, and radiographic imaging was obtained to analyze the remodeling of the buccal bone plate. In the analysis of the resulting distance between the implant shoulder and the bone crest, statistically significant differences were found in the SCTG when compared to the ECTG (P = .02) and ECCG (P = .03). For mean value comparison of the resulting linear distance between the implant surface and the buccal plate, no statistically significant difference was found among all groups (P > .05). The same result was observed in the parameter for presence or absence of tissue formation between the implant surface and buccal plate. Equicrestally placed implants, in this methodology, presented little or no loss of the buccal bone. The subcrestally positioned implants presented loss of buccal bone, even though synthetic bone graft was used. The buccal bone, however, was always coronal to the implant shoulder.

An extraordinary new species of Melanophryniscus (Anura, Bufonidae) from southeastern Brazil

We describe a new species of bufonid from a lowland, sandy soil, restinga habitat in the state of Espirito Santo, southeastern Brazil. Based on the shared occurrence of putative morphological synapomorphies of Melanophryniscus and the results of a phylogenetic analysis of DNA sequences of a broad sample of bufonids, and other anurans, we assign the new species to Melanophryniscus. The new species possesses several peculiar character states that distinguish it from all other Melanophryniscus including, but not limited to: fingers II, III, and V much reduced; nuptial pad with few enlarged, brown-colored spines on medial margin of finger II; seven presacral vertebrae, the last fused with the sacrum; and ventral humeral crest prominent, forming a spinelike projection.

Gingival Papilla Dimensions in Anterosuperior Regions Adjacent to Single-Tooth Implants

This study compared the dimensions of gingival papillae in anterosuperior areas presenting at natural teeth (teeth sites) or single-tooth implants adjacent to natural teeth (implant-tooth sites) by analyzing determined distances. A total of 45 teeth and 46 implant-tooth sites were carefully selected. Clinical evaluation consisted of visual and quantitative analyses with millimeter grids on radiographs. Implant-tooth sites showed a smaller gingival papilla dimension than tooth sites (P < .01). Both evaluated distances (contact point to bone crest and between the roots of adjacent teeth or implant platform to root of adjacent tooth) in all groups significantly influenced the presence/absence of gingival papillae (P < .01). (Int J Periodontics Restorative Dent 2012;32:93-100.)

RGMa and RGMb expression pattern during chicken development suggest unexpected roles for these repulsive guidance molecules in notochord formation, somitogenesis, and myogenesis

Background: Repulsive guidance molecules (RGM) are high-affinity ligands for the Netrin receptor Neogenin, and they are crucial for nervous system development including neural tube closure; neuronal and neural crest cell differentiation and axon guidance. Recent studies implicated RGM molecules in bone morphogenetic protein signaling, which regulates a variety of developmental processes. Moreover, a role for RGMc in iron metabolism has been established. This suggests that RGM molecules may play important roles in non-neural tissues. Results: To explore which tissues and processed may be regulated by RGM molecules, we systematically investigated the expression of RGMa and RGMb, the only RGM molecules currently known for avians, in the chicken embryo. Conclusions: Our study suggests so far unknown roles of RGM molecules in notochord, somite and skeletal muscle development. Developmental Dynamics, 2012. (C) 2012 Wiley Periodicals, Inc.

Alveolar Bone Morphology in Patients With Bilateral Complete Cleft Lip and Palate in the Mixed Dentition: Cone Beam Computed Tomography Evaluation

Objectives: To verify the thickness and level of alveolar bone around the teeth adjacent to the cleft by means of cone beam computed tomography (CBCT) in patients with complete bilateral cleft lip and palate prior to bone graft surgery and orthodontic intervention. Method: The sample comprised 10 patients with complete bilateral cleft lip and palate (five boys and five girls) in the mixed dentition. The mean age was 9.5 years, and all subjects showed a G3 interarch relationship according to the Bauru index. The thickness of alveolar bone surrounding the maxillary incisors and the maxillary canines was measured in CBCT axial section using the software iCAT Xoran System. The distance between the alveolar bone crest and the cement-enamel junction (CEJ) was measured in cross sections. Results: The tomography images showed a thin alveolar bone plate around teeth adjacent to clefts. No bone dehiscence was observed in teeth adjacent to clefts during the mixed dentition. A slight increase in the distance between the alveolar bone crest and the CEJ was observed in the mesial and lingual aspects of canines adjacent to cleft. Conclusion: In patients with BCLP in the mixed dentition, teeth adjacent to the alveolar cleft are covered by a thin alveolar bone plate. However, the level of alveolar bone crest around these teeth seems to be normal, and no bone dehiscence was identified at this age.

Non-functionant urinary bladder paraganglioma

Introduction: Paragangliomas are rare tumors origined on chromaffin-cells of neural crest and can be located from skull base to pelvis, on sympathetic or parasympathetic paraganglia. They account on less than 0,06% of all urinary bladder tumors, with only few hundreds of cases reported in literature since the first record by Zimmermmann in 1953. Case Report: A 63 year-old woman referring irritative urinary symptoms was submitted to an ultrassonography that disclosed an irregular-shaped nodulation on her bladder. CT confirmed the existence of a nodulation on bladder's anterior wall. Patient had normal levels of urinary catecholamins and Vanilmandelic acid. Tumor was excised and posterior immunohistochemical study revealed it was a paraganglioma. Nowadays, ten months after surgery, patient stills healthy and disease-free. Discussion: Paragangliomas can be classified as functionant or non-functionant, according to its production of cathecolamins, which can cause the same symptom complex of pheocromocytomas. About 10-15% of bladder paragangliomas are malignant, and potential metastasis are more common to lymph nodes, lungs and bones. 131-MIBG iodine cyntilography is the most sensitive method for diagnosis and surgery (transurethral resection or cystectomy) is the best choice for treatment.

Cloning and characterization of a novel alternatively spliced transcript of the human CHD7 putative helicase

Abstract Background The CHD7 (Chromodomain Helicase DNA binding protein 7) gene encodes a member of the chromodomain family of ATP-dependent chromatin remodeling enzymes. Mutations in the CHD7 gene are found in individuals with CHARGE, a syndrome characterized by multiple birth malformations in several tissues. CHD7 was identified as a binding partner of PBAF complex (Polybromo and BRG Associated Factor containing complex) playing a central role in the transcriptional reprogramming process associated to the formation of multipotent migratory neural crest, a transient cell population associated with the genesis of various tissues. CHD7 is a large gene containing 38 annotated exons and spanning 200 kb of genomic sequence. Although genes containing such number of exons are expected to have several alternative transcripts, there are very few evidences of alternative transcripts associated to CHD7 to date indicating that alternative splicing associated to this gene is poorly characterized. Findings Here, we report the cloning and characterization by experimental and computational studies of a novel alternative transcript of the human CHD7 (named CHD7 CRA_e), which lacks most of its coding exons. We confirmed by overexpression of CHD7 CRA_e alternative transcript that it is translated into a protein isoform lacking most of the domains displayed by the canonical isoform. Expression of the CHD7 CRA_e transcript was detected in normal liver, in addition to the DU145 human prostate carcinoma cell line from which it was originally isolated. Conclusions Our findings indicate that the splicing event associated to the CHD7 CRA_e alternative transcript is functional. The characterization of the CHD7 CRA_e novel isoform presented here not only sets the basis for more detailed functional studies of this isoform, but, also, contributes to the alternative splicing annotation of the CHD7 gene and the design of future functional studies aimed at the elucidation of the molecular functions of its gene products.

Impact of different fluoride concentrations and pH of dentifrices on tooth erosion/abrasion in vitro

Background: This in vitro study analysed the effect of different fluoride concentrations in acidic or neutral liquid dentifrices in protecting enamel and dentine from erosive and abrasive wear. Methods: Bovine enamel and dentine specimens (n = 132) were randomly allocated to 11 groups (each n = 12): experimental liquid dentifrices with 550 ppm F, 1100 ppm F, 5000 ppm F or 0 ppm F/placebo (each at pH 4.5 and pH 7.0); and commercial dentifrices with 550 ppm F (Colgate Baby, pH 7.0), 1100 ppm F (Crest, pH 7.0) and 5000 ppm F (Duraphat, pH 7.0). The specimens were subjected to erosion for 90 seconds, 4 times/day, over 7 days. Immediately after the first and last erosion, the specimens were brushed for 15 seconds using one of the dentifrices. Tooth wear was measured profilometrically (lm) and analysed by ANOVA (p < 0.05). Results: All fluoridated liquid dentifrices significantly reduced enamel wear compared to the placebo and commercial dentifrices. Only liquid dentifrices with 1100 and 5000 ppm F significantly reduced dentine wear compared to placebo dentifrice. The pH had no effect, but the consistency had a significant impact on the effect of dentifrices. Conclusions: Liquid dentifrices with high F concentration appear to be a good option to prevent tooth wear

Biomechanical comments about Triassic dinosaurs from Brazil

Triassic dinosaurs of Brazil are found in Santa Maria and Caturrita formations, Rio Grande do Sul state, Brazil. There are three species known from the Santa Maria Formation (Staurikosaurus pricei, Saturnalia tupiniquim and Pampadromaeus barberenai), and two from Caturrita Formation (Guaibasaurus candelariensis and Unaysaurus tolentinoi). These dinosaur materials are, for the most part, well preserved and allow for descriptions of musculature and biomechanical studies. The lateral rotation of the Saturnalia femur is corroborated through calculations of muscle moment arms. The enhanced supracetabular crest of Saturnalia, Guaibasaurus, Staurikosaurus, Herrerasaurus ischigualastensis, Efraasia minor and Chormogisaurus novasi suggests that basal dinosaurs may have maintained an inclination of the trunk at least 20º on the horizontal axis. The pectoral girdle articulation of basal sauropodomorphs (Saturnalia and Unaysaurus) was established using a new method, the Clavicular Ring, and the scapular blade remains near 60º on the horizontal axis. This is a plesiomorphic condition among sauropodomorphs and is also seen in the articulated plateosauridae Seitaad ruessi. The Brazilian basal dinosaurs were lightweight with a body mass estimated around 18.5 kg for Staurikosaurus, 6.5 kg for Saturnalia, and 17 kg for Guaibasaurus. Pampadromaeus probably weighed 2.5 kg, but measures of its femur are necessary to confirm this hypothesis. The Triassic dinosaurs from Brazil were diversified but shared some functional aspects that were important in an evolutionary context.

Morse taper implants at different bone levels: a finite element analysis of stress distribution

AIM: To explore the biomechanical effects of the different implantation bone levels of Morse taper implants, employing a finite element analysis (FEA). METHODS: Dental implants (TitamaxCM) with 4x13 mm and 4x11 mm, and their respective abutments with 3.5 mm height, simulating a screwed premolar metal-ceramic crown, had their design performed using the software AnsysWorkbench 10.0. They were positioned in bone blocks, covered by 2.5 mm thickness of mucosa. The cortical bone was designed with 1.5 mm thickness and the trabecular bone completed the bone block. Four groups were formed: group 11CBL (11 mm implant length on cortical bone level), group 11TBL (11 mm implant length on trabecular bone level), group 13CBL (13mm implant length on cortical bone level) and group 13TBL (13 mm implant length on trabecular bone level). Oblique 200 N loads were applied. Von Mises equivalent stresses in cortical and trabecular bones were evaluated with the same design program. RESULTS: The results were shown qualitatively and quantitatively by standard scales for each type of bone. By the results obtained, it can be suggested that positioning the implant completely in trabecular bone brings harm with respect to the generated stresses. Its implantation in the cortical bone has advantages with respect to better anchoring and locking, reflecting a better dissipation of the stresses along the implant/bone interfaces. In addition, the search for anchoring the implant in its apical region in cortical bone is of great value to improve stabilization and consequently better stress distribution. CONCLUSIONS: The implant position slightly below the bone in relation to the bone crest brings advantages as the best long-term predictability with respect to the expected neck bone loss.

QSAR models for inhibitors of physiological impact of Escherichia coli that leads to diarrhea

Quantitative structure – activity relationships (QSARs) developed to evaluate percentage of inhibition of STa-stimulated (Escherichia coli) cGMP accumulation in T84 cells are calculated by the Monte Carlo method. This endpoint represents a measure of biological activity of a substance against diarrhea. Statistical quality of the developed models is quite good. The approach is tested using three random splits of data into the training and test sets. The statistical characteristics for three splits are the following: (1) n = 20, r2 = 0.7208, q2 = 0.6583, s = 16.9, F = 46 (training set); n = 11, r2 = 0.8986, s = 14.6 (test set); (2) n = 19, r2 = 0.6689, q2 = 0.5683, s = 17.6, F = 34 (training set); n = 12, r2 = 0.8998, s = 12.1 (test set); and (3) n = 20, r2 = 0.7141, q2 = 0.6525, s = 14.7, F = 45 (training set); n = 11, r2 = 0.8858, s = 19.5 (test set). Based on the proposed here models hypothetical compounds which can be useful agents against diarrhea are suggested.

Funzionalizzazione della mandibola dopo ricostruzione con lembo libero rivascolarizzato di fibula "single strut". Al di là del deficit di verticalità.

Obiettivi: Valutare la modalità  più efficace per la riabilitazione funzionale del limbo libero di fibula "single strut", dopo ampie resezioni per patologia neoplastica maligna del cavo orale. Metodi: Da una casistica di 62 ricostruzioni microvascolari con limbo libero di fibula, 11 casi sono stati selezionati per essere riabilitati mediante protesi dentale a supporto implantare. 6 casi sono stati trattati senza ulteriori procedure chirurgiche ad eccezione dell'implantologia (gruppo 1), affrontando il deficit di verticalità  della fibula attraverso la protesi dentaria, mentre i restanti casi sono stati trattati con la distrazione osteogenetica (DO) della fibula prima della riabilitazione protesica (gruppo 2). Il deficit di verticalità  fibula/mandibola è stato misurato. I criteri di valutazione utilizzati includono la misurazione clinica e radiografica del livello osseo e dei tessuti molli peri-implantari, ed il livello di soddisfazione del paziente attraverso un questionario appositamente redatto. Risultati: Tutte le riabilitazioni protesiche sono costituite da protesi dentali avvitate su impianti. L'età  media è di 52 anni, il rapporto uomini/donne è di 6/5. Il numero medio di impianti inseriti nelle fibule è di 5. Il periodo massimo di follow-up dopo il carico masticatorio è stato di 30 mesi per il gruppo 1 e di 38.5 mesi (17-81) di media per il gruppo 2. Non abbiamo riportato complicazioni chirurgiche. Nessun impianto è stato rimosso dai pazienti del gruppo 1, la perdita media di osso peri-implantare registrata è stata di 1,5 mm. Nel gruppo 2 sono stati riportati un caso di tipping linguale del vettore di distrazione durante la fase di consolidazione e un caso di frattura della corticale basale in assenza di formazione di nuovo osso. L'incremento medio di osso in verticalità è stato di 13,6 mm (12-15). 4 impianti su 32 (12.5%) sono andati persi dopo il periodo di follow-up. Il riassorbimento medio peri-implantare, è stato di 2,5 mm. Conclusioni: Le soluzioni più utilizzate per superare il deficit di verticalità  del limbo libero di fibula consistono nell'allestimento del lembo libero di cresta iliaca, nel posizionare la fibula in posizione ideale da un punto di vista protesico a discapito del profilo osseo basale, l'utilizzo del lembo di fibula nella versione descritta come "double barrel", nella distrazione osteogenetica della fibula. La nostra esperienza concerne il lembo libero di fibula che nella patologia neoplastica maligna utilizziamo nella versione "single strut", per mantenere disponibili tutte le potenzialità  di lunghezza del peduncolo vascolare, senza necessità  di innesti di vena. Entrambe le soluzioni, la protesi dentale ortopedica e la distrazione osteogenetica seguita da protesi, entrambe avvitate su impianti, costituiscono soluzioni soddisfacenti per la riabilitazione funzionale della fibula al di là  del suo deficit di verticalità . La prima soluzione ha preso spunto dall'osservazione dei buoni risultati della protesi dentale su impianti corti, avendo un paragonabile rapporto corona/radice, la DO applicata alla fibula, sebbene sia risultata una metodica con un numero di complicazioni più elevato ed un maggior livello di riassorbimento di osso peri-implantare, costituisce in ogni caso una valida opzione riabilitativa, specialmente in caso di notevole discrepanza mandibulo/fibulare. Decisiva è la scelta del percorso terapeutico dopo una accurata valutazione di ogni singolo caso. Vengono illustrati i criteri di selezione provenienti dalla nostra esperienza.

Valutazione sperimentale della rigenerazione cartilaginea articolare dopo stimolazione biofisica con campi elettromagnetici pulsati in associazione a trattamenti chirurgici

Diverse tecniche di ingegneria tessutale sono state sviluppate per promuovere la riparazione delle lesioni della cartilagine articolare. Nonostante i buoni risultati clinici a breve termine, il tessuto rigenerato fallisce nel tempo poiché non possiede le caratteristiche meccaniche e funzionali della cartilagine articolare nativa. La stimolazione con campi elettromagnetici pulsati (CEMP) rappresenta un approccio terapeutico innovativo. I CEMP aumentano l’attività anabolica dei condrociti con conseguente incremento della sintesi della matrice, e limitano l’effetto catabolico delle citochine pro-infiammatorie riducendo la degradazione della cartilagine nel microambiente articolare. I CEMP agiscono mediante l’up-regolazione dei recettori adenosinici A2A potenziando il loro affetto anti-infiammatorio. Lo scopo di questo studio è stato quello di valutare l’effetto della stimolazione con CEMP sulla guarigione di difetti osteocondrali in un modello sperimentale nel coniglio. Un difetto osteocondrale del diametro di 4mm è stato eseguito nel condilo femorale mediale di entrambe le ginocchia di 20 conigli. A destra la lesione è stata lasciata a guarigione spontanea mentre a sinistra e stata trattata mediante inserimento di scaffold collagenico o trapianto di cellule mesenchimali midollari sul medesimo scaffold precedentemente prelevate dalla cresta iliaca. In base al trattamento eseguito 10 animali sono stati stimolati con CEMP 4 ore/die per 40 giorni mentre altri 10 hanno ricevuto stimolatori placebo. Dopo il sacrificio a 40 giorni, sono state eseguite analisi istologiche mediante un punteggio di O’Driscoll modificato. Confrontando le lesioni lasciate a guarigione spontanea, la stimolazione con CEMP ha migliorato significativamente il punteggio (p=0.021). Lo stesso risultato si è osservato nel confronto tra lesioni trattate mediante trapianto di cellule mesenchimali midollari (p=0.032). Nessuna differenza è stata osservata tra animali stimolati e placebo quando la lesione è stata trattata con il solo scaffold (p=0.413). La stimolazione con CEMP è risultata efficace nel promuovere la guarigione di difetti osteocartilaginei in associazione a tecniche chirurgiche di ingegneria tessutale.

Wave driven devices for the oxygenation of bottom layers

This thesis discusses the design of a system to use wave energy to pump oxygen-rich surface water towards the bottom of the sea. A simple device, called OXYFLUX, is proposed in a scale model and tested in a wave flume in order to validate its supposed theoretical functioning. Once its effectiveness has been demonstrated, a overset mesh, CFD model has been developed and validated by means of the physical model results. Both numerical and physical results show how wave height affects the behavior of the device. Wave heights lower than about 0.5 m overtop the floater and fall into it. As the wave height increases, phase shift between water surface and vertical displacement of the device also increases its influence on the functioning mechanism. In these situations, with wave heights between 0.5 and 0.9 m, the downward flux is due to the higher head established in the water column inside the device respect to the outside wave field. Furthermore, as the wave height grows over 0.9 m, water flux inverts the direction thanks to depression caused by the wave crest pass over the floater. In this situation the wave crest goes over the float but does not go into it and it draws water from the bottom to the surface through the device pipe. By virtue of these results a new shape of the floater has been designed and tested in CFD model. Such new geometry is based on the already known Lazzari’s profile and it aims to grab as much water as possible from the wave crest during the emergence of the floater from the wave field. Results coming from the new device are compared with the first ones in order to identify differences between the two shapes and their possible areas of application.

Analysis and mathematical modeling of wave-structure interaction

The aim of this thesis, included within the THESEUS project, is the development of a mathematical model 2DV two-phase, based on the existing code IH-2VOF developed by the University of Cantabria, able to represent together the overtopping phenomenon and the sediment transport. Several numerical simulations were carried out in order to analyze the flow characteristics on a dike crest. The results show that the seaward/landward slope does not affect the evolution of the flow depth and velocity over the dike crest whereas the most important parameter is the relative submergence. Wave heights decrease and flow velocities increase while waves travel over the crest. In particular, by increasing the submergence, the wave height decay and the increase of the velocity are less marked. Besides, an appropriate curve able to fit the variation of the wave height/velocity over the dike crest were found. Both for the wave height and for the wave velocity different fitting coefficients were determined on the basis of the submergence and of the significant wave height. An equation describing the trend of the dimensionless coefficient c_h for the wave height was derived. These conclusions could be taken into consideration for the design criteria and the upgrade of the structures. In the second part of the thesis, new equations for the representation of the sediment transport in the IH-2VOF model were introduced in order to represent beach erosion while waves run-up and overtop the sea banks during storms. The new model allows to calculate sediment fluxes in the water column together with the sediment concentration. Moreover it is possible to model the bed profile evolution. Different tests were performed under low-intensity regular waves with an homogeneous layer of sand on the bottom of a channel in order to analyze the erosion-deposition patterns and verify the model results.