Histological evaluation of dog permanent teeth after traumatic intrusion of their primary predecessors

Abstract –  The aims of this study were to analyze the histomorphology of developing permanent teeth whose primary teeth had suffered traumatic intrusion, as well as to compare the influence of immediate extraction of the intruded tooth to passive re-eruption. Nine dogs from 45 to 50 days old were submitted to the intrusion of the maxillary central and lateral primary incisors using a force applicator adapted to the teeth incisal cuspids. The right side intruded teeth were kept in their sockets and the ones on the left side were extracted 30 min later. After a postoperatory periods of 30 and 60 days, four (group 1) and five (group 2) dogs, respectively, were killed by perfusion. The histological evaluations showed that, in group 1, alterations had occurred in the odontoblastic layer and deposition of the enamel matrix had taken place in some specimens while in group 2, a portion of non-mineralized matrix was observed. We concluded that the morphological changes were because of the immediate trauma of intrusion. No differences were found between the groups where the primary tooth was immediately extracted or left to passively re-erupt.     

Immunoblotting human C4 bound to human erythrocytes in vivo and in vitro.

A study of C4 bound to human erythrocytes in vitro and in vivo has been made by immunoblotting with mouse monoclonal anti-C4c and anti-C4d and human polyclonal anti-C4d (Rodgers and Chido) following SDS-PAGE. Multi-banded patterns differentiated between C4A and C4B isotypes. Treatment of EC4b with trypsin eliminated immunoblotting but not agglutination reactions. Serum inactivation (factor I) of EC4b resulted in banding patterns similar to those obtained from patients' EC4d. Treatment of EC4b membranes with NH2OH affected many of the bands, two were lost, one was markedly reduced and others had altered SDS-PAGE mobility. Interpretation of the bands has been made in terms of C4-acceptor complexes and inactivation fragments of C4. A distinct difference in the banding of C4A and C4B isotypes has been detected.     

Treatment of traumatized primary teeth: a conservative approach

This retrospective study examined some different types of treatment to primary teeth. The aim of this study was to assess the treatment of traumatized primary teeth and the importance of a long-term follow up. Brazilian children in the age group of 1-4 years from a baby clinic took part in the study. Three hundred and fifteen patients suffered some type of traumatic injury, a total of 338 affected teeth. Data were registered in specific records and submitted to statistic analysis. The most prevalent type of treatment was monitor only (85%) followed by tooth extraction and endodontic procedure. Invasive treatments were performed in case of severe traumas, usually 6 months after the injury. We verified that a careful follow up might be the preferential choice to the treatment of traumatic primary teeth even in some severe cases.     

Human imaging of phosphorus in cortical and trabecular bone in vivo.

Phosphorus was imaged in vivo in human cortical and trabecular bone and the T(1) and T(2) (*) were measured. An ultrashort TE (UTE) pulse sequence (TE = 70 microm) was used with half pulse excitation and radial mapping of k-space from the center out. T(2) (*) was measured using multiple echo times and T(1) was measured both by saturation recovery and by a method using different RF pulse amplitudes. Seven normal subjects (32-85 years) were examined. Phosphorus was imaged, with a true in-plane resolution of 2.9 x 2.9 mm and a signal-to-noise ratio (SNR) of 19:1, in both cortical and trabecular bone. The mean T(2) (*) value was 207 +/- 12 micros, and the mean T(1) value was 8.6 +/- 3.0 sec. Images and measurements were obtained in realistic times on a clinical MR system. This may provide a new approach to characterizing disease of bone.