Opinions about the clinical utility of platelet-rich plasma (PRP) vary, as a large number of experimental studies have questioned its efficacy. The purpose of this study was to evaluate the effects of PRP on experimental alveolar wound healing in rats. Fifty young adult male Wistar rats were divided in control and PRP groups and submitted to extraction of the right maxillary incisor. In the PRP group, blood was collected by cardiac puncture, and the socket was filled with a PRP gel. Animals were euthanized after 1, 3, 7, 14 and 30 days. Histological and histomorphometric analyses were performed at each experimental time point. Semiquantitative histological analysis showed that the PRP group exhibited significantly more collagen-matrix deposition and less bone-matrix formation in the socket than did the control group from 7 to 30 days. Histomorphometric analyses showed that the PRP group also exhibited lower bone-tissue areas than the control group at 7 (p=0.0250) and 14 days (p<0.0001), but at 30 days, no significant difference between the groups was observed. In the present study, PRP did not enhance alveolar wound healing, and PRP-treated rats exhibited low rates of bone deposition during the intermediate phases of alveolar socket repair.

Las opiniones sobre la utilidad clínica del plasma rico en plaquetas (PRP) varían, ya que un gran número de estudios experimentales han cuestionado su eficacia. El propósito de este estudio fue evaluar los efectos del PRP sobre la cicatrización experimental de heridas alveolares en ratas. Cincuenta ratas Wistar adultas fueron divididas en grupos control y PRP, y fueron sometidas a extracción del incisivo maxilar derecho. En el grupo de PRP, la sangre se recogió por punción cardiaca, y el alvéolo se llenó con un gel de PRP. Los animales se sacrificaron después de 1, 3, 7, 14 y 30 días. Se realizaron análisis histológicos e histomorfométricos en cada momento experimental. El análisis histológico semicuantitativo mostró que el grupo de PRP exhibió significativamente más deposición de matriz de colágeno y menos formación de matriz ósea en el receptáculo que el grupo control de 7 a 30 días. Los análisis histomorfométricos mostraron que el grupo PRP también exhibió áreas de tejido óseo inferiores al grupo control a 7 (p = 0,0250) y 14 días (p <0,0001), pero a los 30 días no se observó diferencia significativa entre los grupos. En el presente estudio, el PRP no mejoró la cicatrización de las heridas alveolares, y las ratas tratadas con PRP mostraron bajas tasas de deposición ósea durante las fases intermedias de la reparación de los receptáculos alveolares.

Os efeitos da fratura unilateral do arco zigomático no crescimento facial foram avaliados através de mensurações cefalométricas. Fratura com desvio medial no lado direito foi realizada em ratos com um mês de idade. Os animais foram sacrificados com três meses de idade e sua mandíbula foi desarticulada. O crânio foi submetido à tomada radiográfica axial e as hemimandíbulas à norma lateral. As mensurações foram realizadas através de um sistema de computador. Foi verificada diferença significante a menor para a altura do corpo e do ramo da mandíbula. Não houve diferença significante para a profundidade da fossa infratemporal, bem como para as diversas mensurações na maxila e para o comprimento mandibular. A tendência de retorno do arco zigomático com desvio à sua posição original foi confirmada.

The effect of unilateral zygomatic arch fracture on facial growth was analysed by means of cephalometric measurements. Medially displaced fracture of the right side was achieved in one month old rats. Reaching three months the animals were sacrified, and their mandibles disarticulated. The skull was submitted to axial radiographic incidence and the hemimandibles to a lateral radiographic incidence. The measurements were made through a computer system. Significant differences were verified with a decrease in body height and ramus of the mandible. There was no significant difference in infratemporal fossae depth, as well as in diverse measurements in maxilla and in mandibular lenght. The tendency of the fractured arch to return to its original position was confirmed.

O comportamento da fratura do arco zigomático no período de crescimento foi avaliado através de mensurações cefalométricas. Fratura com desvio medial no lado direito foi realizada em ratos com um mês de idade. Foi verificada tendência de retorno do arco fraturado à sua posição original, porém, com diferença estatisticamente significante para a profundidade da fossa infratemporal. Entretanto, não houve diferença significante para a distância entre o arco zigomático e a mandíbula, o que pode ser explicado pela presença de desvio significante da mandíbula.

The behavior of the zygomatic arch fracture in the growth period was analyzed by means of cephalometric measurements. Medially displaced fracture of the right side was provoked in one-month-old rats. There was a tendency of the fractured arch to return to its original position, but with statistically significant differences as to the depth of the infratemporal fossa. However, there was no significant difference regarding the distance between zygomatic arch and mandible, which can be explained by the presence of significant deviation of the mandible.