Bone density changes in the apical area after rapid orthodontic extrusion of subgingivally fractured tooth / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the bone density changes in the apical area of subgingivally fractured tooth after rapid orthodontic extrusion.</p><p><b>METHODS</b>Twelve fractured incisors in 11 patients extended 2 - 5 mm below the gingival line were selected. Two weeks after root canal therapy, the subgingival fragment was lifted up and the fracture line was brought 1.5 - 2.0 mm above the level of the gingival line by means of edgewise fixed appliance. After the extrusion completed, the tooth had been stabilized and held for 6 months. The CT Analyser software was used to measure the bone density changes in the apical area on radiographs once a month. Changes of relative value in bone density was quantitatively analyzed.</p><p><b>RESULTS</b>The average period of extrusion was 11 days. The relative value of bone density in the apical region was -39.6% immediately after extrusion and continuously increased afterwards. In the third month, the value (18.5%) changed most rapidly (P < 0.01).</p><p><b>CONCLUSIONS</b>Under the continuous and proper tooth axial extrusion force, the tooth moved rapidly and steadily. The bone density in the apical area approached normal value within 3 months after treatment.</p>

Esthetics restoration after rapid orthodontic extrusion of subgingivally fractured incisor: a case report / 华西口腔医学杂志

A case of a patient with subgingivally fractured incisor was presented. Two weeks after root canal therapy, the subgingival fragment was restored with fiber post, resin core and temporary crown. Gingivoplasty was performed around. after the subgingival fragment had been elevated in the axial direction by means of edgewise fixed appliance. Stabilized and held for 6 months, the incisor was restored with all ceramic crown. Optimal esthetic was achieved when restoration was performed after rapid orthodontic extrusion which had lifted up the fracture line above the level of the gingival line within 14 days. At 6-month follow-up, the periodontal tissues were normal and neither luxation nor relapse was noted.

Influence of repeated sintering on the color of two brands of porcelain-fused-to-titanium / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the influence of repeated sintering on the color of two porcelain-fused-to-titanium, and the differences between the two porcelains.</p><p><b>METHODS</b>Thirty samples were prepared and sintered for 9 times. The color of samples were measured following sintering 1, 3, 5, 7, 9 times by ShadeEye NCC colorimeter according to two brands of porcelains with CIE1976L*a*b* color system, and calculated relevant chrome, chromatism and hue, and statistical analysis.</p><p><b>RESULTS</b>When two brands of porcelains were sintered 5 times, the color parameters had no significant change and sintered continuely, the color parameters of L* and a* had obvious changes, but can't be observed by eyes.</p><p><b>CONCLUSION</b>The color parameters of titanium-porcelains have no significant change after repeated sintering.</p>