Morphological characteristics of the facial bone wall related to the tooth position in the alveolar crest in the maxillary anterior

The purpose of this study was to analyze whether the position of the tooth in the alveolar ridge influences the thickness of the facial bone wall and the distance between the cemento-enamel junction (CEJ) and osseous zenith (OZ). Cone-beam computed tomography (CBCT) scans from fifty four dentate patients were included in the study (22 male and 32 female, mean age 41. 5 years). The measurements taken included: (1). The Facial bone thickness at 7 different equidistant levels -measuring levels (ML 1-7) - between OZ and the root apex (A). (2) The CEJ -OZ distance. (3) Facial position of the tooth (FPT) relative to a straight line traced from mesial to distal interproximal depressions of the alveolar plate at the level of the CEJ. The Facial bone wall thickness ranged between 0 mm and 3. 8 mm, with greater values at more apical levels. Mean values were smaller than 1 mm at every level except ML7. The CEJ-OZ distance varied between 0. 5 mm and 6. 9 mm (mean 2. 9 mm). The Mean of FPT value was 0. 6 mm. No statistically significant correlation was found between FPT and the CEJ-OZ distance. Weak negative statistically significant correlations were found between FPT and the thickness of the facial bone wall at MP1 and MP3. Within the limits of this study, no clinically relevant correlation between FPT and facial bone thickness - CEJ-OZ distance was found. More studies should be conducted to evaluate a greater number of teeth, especially those that may present misalignment with greater FPT values.El objetivo del presente estudio fue analizar si la posición de la pieza dentaria en el reborde alveolar influencia el espesor de la tabla ósea vestibular y la distancia entre el limite amelo-cementario (LAC) y el cenit óseo (CO). Tomografías computadas haz de cono (TC) de 54 pacientes dentados fueron incluidas en el estudio (22 hombres y 32 mujeres, edad promedio 41. 5 anos). Las medidas registradas fueron: (1) espesor de la tabla ósea vestibular en 7 diferentes niveles de medición (NM1-7) entre CO y el ápice radicular (AR). (2) La distancia LAC-CO. (3) Posición vestibular de la pieza dentaria (PVD) en relación a una línea recta trazada desde la depresión interproximal mesial a la depresión interproximal distal de la tabla ósea a nivel del LAC. El espesor de la tabla ósea vestibular fue 0-3. 8mm, con valores mayores registrados a nivel más apical. El valor promedio fue menor a 1 mm excepto en NM7. La distancia LAC-CO varió entre 0. 5 y 6. 9mm (promedio 2. 9mm). El promedio de PVD fue de 0. 6mm. No se encontró correlación estadísticamente significativa entre la PVD y la distancia LAC-CO. Se halló una correlación débil negativa estadísticamente significativa entre la PVD y el espesor de la tabla ósea vestibular en NM1 y NM3. Dentro de las limitaciones de este estudio, no se encontró una correlación clínicamente significativa entre PVD y espesor de la tabla ósea vestibular - distancia LAC-CO. Se deben llevar a cabo más estudios para evaluar un mayor número de piezas dentarias, especialmente aquellas que se encuentran desalineadas con valores PVD mayores

Alveolar dimensional changes relevant to implant placement after minimally traumatic tooth extraction with primary closure

The purpose of this study is to evaluate the dimensional changes that occur in the alveolar ridge after minimally traumatic tooth extraction by means of computed tomography (CT), with special focus on the portion of bone supporting the gingival zenith. Twenty subjects with indication for singlerooted tooth extraction and preserved alveolar walls were selected for this study. After a minimally traumatic extraction, two CT scans were performed; the first within 24 hours postextraction (TC1) and the second 6 months (TC2) later. A radiographic guide with a radiopaque marker was used to obtain references that enabled accurate measurements over time, in both vertical and horizontal directions. The bone crest immediately apical to the gingival zenith was identified and termed "osseous zenith". The displacement of the osseous zenith in horizontal and vertical direction was analyzed and correlated with several alveolar anatomical variables with the aim of identifying possible predictors for bone remodeling. Dimensional changes that occur in postextraction sockets within a 6month period showed significant vertical and horizontal displacement of the osseous zenith (p<0.001). Mean vertical resorption was 2.1 ± 1.7 mm, with a median of 1.9 mm and a range of 0.2 to 7.5 mm. Mean horizontal resorption was 1.8 ± 0.8 mm with a median of 1.7 mm and a range of 0.6 to 4.4 mm. However, no correlation was found between the width of the facial alveolar crest and the displacement of the osseous zenith. The results of the present study showed that if the width of the facial crest at the apicalcoronal midpoint is less than 0.7 mm, a high degree of displacement of the osseous zenith (> 3 mm) should be expected. The present study suggests that the width of the alveolar crest at its midlevel, rather than crestal width, may be correlated with the displacement of the osseous zenith.El objetivo del presente estudio es evaluar los cambios dimen sio nales que ocurren en el reborde alveolar luego de realizar una exodoncia atraumática mediante tomografía computada, con especial atención en el tejido óseo que soporta el cénit gingival. Se seleccionaron 20 sujetos con indicación de exodoncia de piezas unirradiculares y que presentaban las paredes alveolares conservadas. Luego de llevar a cabo una exodoncia atraumática se realizaron dos tomografías computadas (TC); la primera dentro de las 24 hs postexodoncia (TC1) y la segunda a los 6 meses (TC2). Se utilizó una guía radiológica con un marcador radiopaco para obtener medidas precisas en el tiempo, tanto en el plano horizontal como vertical. Se identificó la cresta ósea inmediatamente apical al cénit gingival y se definió como “cénit óseo”. Se realizó un análisis del desplazamiento del cénit óseo en el plano horizontal y vertical y se correlacionó con diferentes variables anatómicas con el objetivo de determinar posibles predictores del remo delado óseo. Los cambios dimensionales que ocurren 6 meses postexodoncia mostraron un desplazamiento significativo del cénit óseo (p<0.001) . La reabsorción vertical promedio fue de 2.1 ± 1.7 mm con una media de 1.9 mm y un rango de 0.2 a 7.5 mm. El promedio de reabsorción horizontal fue de 1.8 ± 0.8 mm con una media de 1.7 mm y un rango de 0.6 a 4.4 mm. No se halló correlación entre el ancho de la cresta vestibular y el desplazamiento del cénit óseo. Los resultados del presente estudio mostraron que si el ancho de la cresta vestibular en el punto medio (en sentido apicocoronal) es menor a 0.7mm se puede esperar un desplazamiento del cénit óseo (>3mm). Este estudio sugiere que el ancho de la cresta alveolar en su punto medio podría predecir el desplazamiento del cénit óseo

Black holes, gravitational waves and fundamental physics: a roadmap

The grand challenges of contemporary fundamental physics—dark matter, dark energy, vacuum energy, inflation and early universe cosmology, singularities and the hierarchy problem—all involve gravity as a key component. And of all gravitational phenomena, black holes stand out in their elegant simplicity, while harbouring some of the most remarkable predictions of General Relativity: event horizons, singularities and ergoregions. The hitherto invisible landscape of the gravitational Universe is being unveiled before our eyes: the historical direct detection of gravitational waves by the LIGO-Virgo collaboration marks the dawn of a new era of scientific exploration. Gravitational-wave astronomy will allow us to test models of black hole formation, growth and evolution, as well as models of gravitational-wave generation and propagation. It will provide evidence for event horizons and ergoregions, test the theory of General Relativity itself, and may reveal the existence of new fundamental fields. The synthesis of these results has the potential to radically reshape our understanding of the cosmos and of the laws of Nature. The purpose of this work is to present a concise, yet comprehensive overview of the state of the art in the relevant fields of research, summarize important open problems, and lay out a roadmap for future progress. This write-up is an initiative taken within the framework of the European Action on 'Black holes, Gravitational waves and Fundamental Physics'

Self-medication in patients seeking care in a dental emergency service

The aims of this work were: To determine what percentage of firsttime patients to the Dental Emergency Department at the School of Dentistry of Buenos Aires University had taken medications to relieve or treat their condition. To determine what percentage of these had used selfmedication, and which were the most frequently taken medicines. To determine whether there is an association between selfmedication and educational level, and between selfmedication and whether the patient has health coverage. This was an observational, crosssectional study which reviewed 567 clinical histories of patients who visited the Dental Emergency Department from March 2015 to September 2016. The following parameters were assessed: sex, age, reason for consultation, medication, dose, interval, duration and indication. Patients' educational level and whether they had health coverage were ascertained. Confidence intervals of 95% were calculated for percentages using the Wilson score method. Inferential analyses were performed using the Chisquare test (ᵪ2). Significance level was set at 5%. Eighty five percent (85%,.n=481) of the patients had taken at least one medication; 77% (n=372) had used selfmedication. The most frequently used medicines were nonsteroid antiinflammatory drugs (61%), antibiotics (34%) and glucocorticoids (2%). No association was found between selfmedication and patients' having health coverage (ᵪ2=13; p=0.08). No significant association was found between educational level and selfmedication (ᵪ2=10; p=0.22). Nevertheless, the lowest percentages of selfmedication were found in subjects with complete university studies (77%; CI95: 60% to 89%), while the highest percentages were found in subjects with incomplete primary education (89%; CI95: 69% to 97%), complete primary education (92%; CI95: 82% to 96%) and incomplete secondary educations (90%; CI95: 84% to 94%).High levels of selfmedication were found in the study population. Although no association was found between educational level and selfmedication behavior, the percentage of selfmedication was higher among patients with lower educational levels. The high level of selfmedication highlights the importance of conducting campaigns to raise awareness about the adequate use of medicines.Fil: Stolbizer, Federico. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Roscher, Daniel F.. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Andrada, Maria M.. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Faes, Lautaro. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Arias, Carla. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Siragusa, Cecilia. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Prada, Silvio. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Saiegh, Jonathan. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Rodriguez, Daniel. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Gualtieri, Ariel Félix. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Mendez, Carlos Fernando. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; Argentin