Moacyr Domingos Novelli

Thickness of the remaining enamel after the preparation of cingulum rest seats on maxillary canines

PURPOSE This study evaluated the level of tissue removal that takes place on enamel and dentin during cingulum rest seat preparation. MATERIAL AND METHODS A quantitative evaluation of the thickness of the remaining enamel of cingulum seat preparations to receive removable partial denture rests was carried out in 20 maxillary canines with a light optical microscope. RESULTS Thirty percent of the preparations were overextended into dentinal tissue, and 85% had depths that were insufficient to receive rests.

FRATURA DO ARCO ZIGOMÁTICO NO PERÍODO DE CRESCIMENTO: ESTUDO EXPERIMENTAL EM RATOS

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.

Efeitos da fratura do arco zigomático no crescimento facial em ratos jovens

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.

Estudo da viabilidade do preparo direto para descanso de cíngulo em incisivo central superior

The present research evaluated the viability of the direct preparation of lingual rest seats in maxillary central incisors. Ten completely sound specimens were embedded in acrylic resin supports and distributed among five specialists who prepared the rest seats. The coronary portion of the teeth was then cut using a previously made incisal index as guide. The preparation was characterized by angular and linear measurements that enabled a comparative analysis between the original outline of the tooth and its respective prepared model, while permitting the determination of dentinal exposure. The observations were undertaken in digitized images of these outlines utilizing a specific computer program. From the fifty models prepared under well-established criteria, thirty-three showed perforation of the enamel. Conclusively, the maxillary central incisor may not be indicated to receive a directly prepared lingual rest seat.

Evaluación del Efecto del Plasma Rico en Plaquetas en la Cicatrización de Heridas Alveolares en Ratas

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 heali ng in rats. Fifty young adult male Wistar rats were divided in control and PRP groups and submitted to extraction of the right maxillary in cisor. 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 hi stological analysis showed that the PRP group exhibited significantly more collagen-matrix deposition and less bone-matrix formation in th e socket than did the control group from 7 to 30 days. Histomorphometric analyses showed that the PRP group also exhibited lower bonetissue areas than the control group at 7 (p=0.0250) and 14 days (p<0.0001), but at 30 days, no significant difference between t he groups was observed. In the present study, PRP did not enhance alveolar wound healing, and PRP-treated rats exhibited low rates of bon e deposition during the intermediate phases of alveolar socket repair.

Quality of linear incisions performed by dental students using Er:YAG laser in soft tissue

Introduction: New technologies in dental practice, such as laser, have enabled new strategies to be established in dental education. The aim of this study was to analyze the difficulties that dental students encountered with performing surgical incisions using Er:YAG laser (LE), and the morphology of these incisions. Material and Methods: Sixteen undergraduate dental students and ten dental professionals (DP) enrolled at The Master of Science Program in Laser Dentistry were asked to perform 15 incisions using an LE and 15 with a conventional scalpel. The incisions were compared, based on the shape factor (relation between area and perimeter), which was obtained by a digital image system and by a morphometry software. Data was submitted to statistical analysis of variance (p 0.05). Results: Considering the incisions performed by scalpel, DP showed statistically significant differences (p < 0.01) in relation to control group (CG). Considering the LE, all groups showed significant differences (p<0.0001) in relation to CG, especially the DP group. The main laser technical failures were performing an incision that was not in a straight line, without defined borders, using an inconstant cutting speed, and absence of suction and water jet appliances. None of the groups performed adequate incisions using LE. Conclusion: Greater emphasis is required in relating laser therapy practice to the physical properties of laser, particularly for dental professionals that specialize in laser.