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PubMedDate not supplied

Comparison of knee motion and callus formation in femoral lengthening with the Wagner or monolateral-ring device.

Twenty-three patients who underwent femoral lengthening had proximal fixation with two Shanz screws; however, the type of distal fixation and site of the osteotomy differed. One group had distal fixation with two Shanz screws attached to a Wagner device and had a midshaft osteotomy; the other group had distal fixation with an Ilizarov ring attached to a modified Wagner device and underwent metaphyseal osteotomy. Patients were compared with regard to callus formation, presence of knee subluxation, and range of motion (ROM) at the knee. The average lengthening achieved was 9.9 cm. The type of bone healing was superior when the osteotomy was performed in the metaphysis rather than to the diaphysis. Knee ROM was poorer in the group with the distal fixation by the Ilizarov wires than the group with the Shanz pins. Multiple adhesions caused by Ilizarov wire impalement of muscles appeared to have caused the excessive stiffness. In instances of simultaneous ipsilateral lengthening of the femur and tibia, interconnection of the Ilizarov ring by means of hinges was successful in reducing the incidence of knee subluxation.

Adolescent↗

PubMedDate not supplied

Composite resin bond strength after enamel bleaching.

This study evaluated the effect of enamel bleaching with a commercial product on the sheer bond strength of a composite resin. A total of 45 human extracted permanent molars were used. A flat enamel surface was obtained with 600-grit SiC paper. The teeth were then randomly distributed into three groups of 15 teeth each: Group 1: Enamel etching with 37% phosphoric acid gel (Coe) for 60 seconds, placement of an unfilled resin (Coe) thinly applied with a brush and a composite resin (Occlusin); Group 2: Enamel bleaching (Rembrandt Lighten Bleaching Gel, Den-Mat) for one hour, etching for 60 seconds and placement of unfilled and composite resins. Group 3: Enamel bleaching for 24 hours, etching for 60 seconds, and placement of unfilled and composite resins. A nylon ring over the etched enamel retained the composite resin. The teeth were thermocycled (X100) and sheared with a knife-edged blade in an Instron machine running at a cross-head speed of 1 mm/min. The results in MPa were: Group 1: 12.86 +/- 4.83, Group 2: 12.33 +/- 2.95, and Group 3: 7.67 +/- 1.98. An ANOVA revealed that Groups 1 and 2 were significantly different from Group 3 (P < 0.001). Fracture within the enamel occurred in 53% in Group 1, 33% in Group 2, and 0% in Group 3. The study reveals that the shear bond strength of composite resins is significantly reduced after enamel bleaching for 24 hours.

Analysis of Variance↗