OBJECTIVE: This study aimed to evaluate the importance of a distal proximal contact on the load transfer to the posterior region of the mandible by non-splinted adjacent implant-supported crowns using photoelastic stress analysis. MATERIAL AND METHODS: A rectangular model (68x30x15 mm) was made of polymethylmethacrylate resin to simulate half of the mandibular arch. One model was completed with resin replicas representing the first premolar and second molar and with two 3.75 mm dia.x11 mm internal hexagon threaded implants replacing the second premolar and first molar. The other model was manufactured in the same way but without the second molar. Both models were duplicated using photoelastic resin. The roots of the teeth replicas were covered with a layer of polyether impression material to simulate the periodontal ligament. Two different vertical loads were applied to the crowns as follows: 1 - single static point load alternately applied to the crowns replacing the second premolar and first molar (50 N); 2 - simultaneous static point loads applied to both of the crowns replacing the second premolar and first molar (100 N). The resulting isochromatic fringe pattern in the photoelastic model was monitored and photographed. RESULTS: All loading conditions studied showed that the presence of the second molar has changed the load transmission and the pattern of stresses. CONCLUSION: Results showed that the presence of a second molar proximal contact can help minimize the stresses around the implants.

Este estudo avaliou o efeito de soluções para enxaguatório bucal contendo fluoreto sobre a superfície do titânio comercialmente puro (cp Ti) após fundição odontológica. As amostras (n=50) foram divididas igualmente: grupo A - armazenadas em água destilada a 37 ± 1ºC, grupo B - armazenadas em água destilada a 37 ± 1ºC e imersão diária em NaF a 0,05% durante 3 min, grupo C - armazenadas em água destilada a 37 ± 1ºC e imersão diária em NaF a 0,2% durante 3 min, grupo D - armazenadas em água destilada a 37 ± 1ºC e imersão em NaF a 0,05% a cada 15 dias por 3 min e grupo E - armazenadas em água destilada a 37 ± 1ºC e imersão em NaF a 0,2% a cada 15 dias durante 3 min. A rugosidade superficial foi medida logo após o polimento metalográfico das amostras (T0) e cada 15 dias de experiência até serem alcançados 60 dias (T15, T30, T45, T60). Os dados foram analisados usando ANOVA (α=0,05) e as diferenças não foram estatisticamente significantes (p>0,05) entre as diferentes soluções. Conclui-se que soluções contendo fluoreto (pH 7,0) não danificam a superfície do Ti cp e podem ser usadas como soluções para bochecho usadas por pacientes que possuem restaurações à base de titânio.

This study evaluated the effects of fluoride-containing solutions on the surface of commercially pure titanium (CP Ti) obtained by casting. CP Ti specimens were fabricated and randomly assigned to 5 groups (n=10): group 1: stored in distilled water at 37 ± 1ºC; group 2: stored in distilled water at 37 ± 1ºC and daily immersed in 0.05% NaF for 3 min; group 3: stored in distilled water at 37 ± 1ºC and daily immersed in 0.2% NaF for 3 min; group 4: stored in distilled water at 37 ± 1ºC; and immersed in 0.05% NaF every 15 days for 3 min; and group 5: stored in distilled water at 37 ± 1ºC and immersed in 0.2% NaF every 15 days for 3 min. Surface roughness was measured with a profilometer immediately after metallographic polishing of the specimens (T0) and at 15-day intervals until completing 60 days of experiment (T15, T30, T45, T60). Data were analyzed statistically by ANOVA and Tukey's test (α=0.05). There was no statistically significant difference (p>0.05) in surface roughness among the solutions. In conclusion, fluoride-containing solutions (pH 7.0) used as mouthwashes do not damage the surface of cast CP Ti and can be used by patients with titanium-based restorations.

The purpose of this study was to evaluate the newly formed bone, comparing two different carriers for rhBMP-2, using the decortication and nondecorticatication surgical technique in Wistar rat mandibles, evaluated by radiographic densitometry method. It was used fifty six animals according to specific treatment, which were sacrificed after 3 and 6 weeks after this. It was concluded that the decortication surgical technique was able to optimize the osteoinduction properties of the rhBMP-2, independently of the material carrier used and the period of time, according to radiographic densitometry technique.

El propósito de este estudio es evaluar la neoformación ósea con la densitometría radiográfica, comparando dos transportadores diferentes para el rhBMP-2, mediante la técnica quirúrgica con o sin la retirada previa de la cortical ósea, en mandíbulas de ratas Wistar. Fueron utilizados 56 animales, de acuerdo con el tratamiento específico, sacrificados después de 3 y 6 semanas. La densitometría radiográfica permitió concluir que la técnica quirúrgica de retirada de la cortical puede optimizar las características osteoinductoras del rhBMP-2, independientemente del transportador usado y del tiempo transcurrido.

The aim of this study was to evaluate alterations in the masseter muscle of 30 male guinea-pigs submitted to occlusal alteration. The animals were divided into 2 equal groups, the control group (C) only submitted to surgical stress, and the occlusal altered group (T) submitted to teeth extraction. Each group was subdivided into 3 groups, with 5 animals, for the following studies: macroscopy and vessels distribution, light microscopy and histochemical analysis, with animals' perfusion 2 months after surgery. Data were submitted to statistical analysis. Macroscopically, an anteroposterior orientation of the muscular fibers was found and statistical difference between C and T groups in width (p<0.05). Microscopically, C and T groups showed polygonal muscular fibers with variable diameters, and on the left side of the T group these differences were more pronounced. Histochemically, in both groups, the prevalence of intermediate reactivity fibers and several high reactivity fibers spread out in the deeper area was observed, with no significant differences between superficial fibers on both sides of C and T groups. It was possible to conclude that the masseter muscle in guinea-pigs was sensible to functional chewing alteration.

Arecent innovation in dentistry is the preparation and use of platelet-rich plasma (PRP), a concentrated suspension of the growth factors found in platelets. PRP is involved in wound healing and are postulated as promoters of tissue regeneration. This review represents an update of the uses, applications, mechanism of action and clinical benefits of PRP

Innovaciones recientes en odontología son la preparación y uso de plasma enriquecido de plaquetas (platelet-rich plasma, PRP), una suspensión concentrada de factores de crecimiento presentes en las plaquetas. El PRP está involucrado en la cicatrización y se postula su acción como promotor de la regeneración tisular. Esta revisión corresponde a una actualización de los usos, aplicaciones, mecanismos de acción y beneficios clínicos del PRP

The skeleton has several important functions, such as structural functions that provide mobility, support, and protection for the body. It also has an important function as a reservoir for calcium and phosphorus. The aim of this article is to show the principal hormones that are involved with the bone healing process. In this article, it will be pointed the mineral homeostatic mechanisms in the skeleton, controlled by the calcium-regulating hormones: parathyroid hormone (PTH) that maintains the normal extracellular calcium levels by enhancing osteoclastic bone resorption and liberating calcium from the adult skeleton; estrogen, considering that both osteoblasts and osteoclasts express estrogen receptors, it is reasonable to assume that the effects of estrogen on skeletal remodeling could be caused, at least partly, by a direct effect on bone cells; androgen with important functions on the adult male phenotype, anabolic actions on skeleton, muscle and bone, including the effects of their metabolism in diverse tissues; and steroids that inhibit the synthesis of proteins, collagen, and proteoglycans in articular cartilage, and inactivate vitamin D, limiting calcium absorption by the gastrointestinal tract, and increasing the urinary excretion of calcium, they also inhibit the release of growth hormone, which further decreases soft tissue and bone repair and lead to a decrease in bone, ligament, and tendon strength

El esqueleto humano tiene varias importantes funciones, tales como las estructurales que proporcionan la movilidad, soporte y protección del cuerpo. Además, tiene función de reserva de calcio y fósforo. El objetivo de este artículo es mostrar las principales hormonas envueltas en los procesos de reparación ósea. Se muestran los mecanismos de homeostasis mineral en el esqueleto, controlados por las hormonas reguladoras del calcio: hormona de la paratiroide, que mantiene normales los niveles de calcio extracelular aumentando la reabsorción ósea por osteoclastos y liberando el calcio del esqueleto humano; estrógeno, considerando que tanto los oesteoblastos como los osteoclastos presentan receptores para estrógeno, es razonable presumir que los efectos del estrógeno en la remodelación ósea puedan ser causados, por lo menos parcialmente, por un diferente efecto en las células óseas; andrógeno con importantes funciones en el fenotipo masculino, acciones anabólicas en el esqueleto, músculos y huesos, incluyendo los efectos de su metabolismo en diversos tejidos; y esferoides que inhiben la síntesis de proteínas, colágeno y proteoglicanos en el cartílago articular e inactivan la vitamina D, limitando la absorción de calcio por el tracto gastrointestinal y aumentando la excreción urinaria de calcio, ellos también inhiben la liberación de hormona del crecimiento, lo que llevará a una disminución de tejido blando y de la reparación ósea y en consecuencia a una disminución en la fuerza de los huesos, ligamentos y tendones

The aim of this study was to assess a bilateral comparison of the mandible density in both sex young patients with computer densitometry. Fifty panoramic radiographs were obtained from young patients with ages between 18 and 23 years old (group A = 25 female and group B = 25 male) standardized, using the same X-Ray equipment (Siemens, lOKvp, 7mA), scanned with a 282.110 pixels resolution, and transferred later to a computer and using the SIDEXIS (Sirona, USA) program to analyze the bone densitometry performance. Bilateral sites were standardized with the objective to measure the bone density. Obtained data were registered and submitted to statistical analysis. The following means and standard deviations were obtained, in pixels, for the right and the left side, respectively: group A= 154.36±36.90 e 186.12+31.41, group B= 162.07±34.94 and 180.15+30.96. These values show statistical difference between different sides and groups (p<0.05), with a higher bone density on the left side in both groups, especially in group A

El objetivo de este estudio fue realizar una comparación bilateral de la densidad de mandíbula en pacientes jóvenes de ambos sexos con computadora densitométrica ósea. Fueron obtenidas 50 radiografías panorámicas de pacientes jóvenes entre 18 y 23 años de edad (Grupo A = 25 femenino y el grupo B = 25 masculino), utilizando el mismo equipo de radiografía (Siemens, 1 OKvp, 7mA). Se escaneó con una resolución de 282,110 pixels, transfiriéndose luego a un computador para el estudio por medio del programa SIDEXIS (Sirona, USA) para analizar el desempeño densitométrico de hueso. Los sitios bilaterales fueron estandarizados con el objetivo de medir la densidad de hueso. Los datos obtenidos fueron registrados y sometidos a análisis estadístico. Las medias y los desvíos padrón fueron obtenidos en pixels, para el lado derecho y el lado izquierdo, respectivamente: Grupo A = 154,36±36,90 y 186,12±31,41, grupo B = 162,07±34,94 y 180,15±30,96. Estos valores muestran la diferencia estadística entre lados y grupos diferentes (p<0,05), con una densidad más alta de hueso en el lado izquierdo en ambos grupos, especialmente en grupo A

The aim of this study was to analyze the histoenzymological alterations in the masseter muscle, superficial bundle, in guinea pigs induced by the occlusal alteration. The present study permitted to conclude that the masseter muscle, superficial bundle, in guinea-pigs was little sensible to chewing functional alteration in this period of time

El objetivo de este estudio fue analisar las alteraciones mstoenzimológicas de la capa superficial del músculo maseter, inducidas por la alteración oclusal. Los resultados nos llevan a concluir que la capa superficial del referido músculor, en guinea-pigs, es poco sensible a la alteración funcional masticatoria

The aim of this work is to present, by a literature review, the principal characteristics of TGF-beta, in the regulation and new bone formation

Este trabajo tiene como objetivo presentar, por medio de una revisión de la literatura, las principales características de la TGF-beta en la regulación de la neoformación ósea