This study examined the effect of ligation on the load-deflection characteristics of nickel-titanium (NiTi) orthodontic wire. A modified three-point bending system was used for bending the NiTi round wire, which was inserted and ligated in the slots of three brackets, one of which was bonded to each of the three bender rods. Three different ligation methods, stainless steel ligature (SSL), slot lid (SL), and elastomeric ligature (EL), were employed, as well as a control with neither bracket nor ligation (NBL). The tests were repeated five times under each condition. Comparisons were made of load-deflection curve, load at maximum deflection of 2,000 microm, and load at a deflection of 1,500 microm during unloading. Analysis of Variance (ANOVA) and Dunnett's test were conducted to determine method difference (alpha = 0.05). The interaction between deflection and ligation was tested, using repeated-measures ANOVA (alpha = 0.05). The load values of the ligation groups were two to three times greater than the NBL group at a deflection of 1,500 microm during unloading: 4.37 N for EL, 3.90 N for SSL, 3.02 N for SL, and 1.49 N for NBL (P < 0.01). For the EL, a plateau region disappeared in the unloading curve. SL showed the smallest load. The ligation of the bracket wire may make NiTi wire exhibit a significantly heavier load than that traditionally expected. NiTi wire exhibited the majority of its true superelasticity with SL, whereas EL may act as a restraint on its superelasticity.

The purpose of the present study was to develop a three-dimensional (3D) non-radiographic cephalometric system based on Simon's three planes. In pursuit of cephalometry without irradiation of patients, readiness of data and simplicity of the system, a portable 3D computer-aided, contact-method cephalometric system, equipped with newly developed cephalometric software for chairside use, was developed. The feasibility of its clinical use was examined based on comparison of the measurements obtained with those from conventional radiographic cephalometry on a human dry skull, as well as on three living subjects. From a total of nine measurements, a statistically significant difference was seen in six measurements: FMPA, U1/FH, FMIA, ANB, IMPA, and A-Np for the dry skull; in four measurements: FPA, FMPA, U1/FH, and Pog-Np for subject A; in five measurements: FMPA, U1/FH, FMIA, AN/FH, and A-Np for subject B; and in seven measurements: FMA, FMPA, U1/FH, FMIA, ANB, IMPA, and AN/FH for subject C. A clinically significant difference was found only in one measurement, U1/FH for the dry skull, in four measurements FPA, FMPA, U1/FH, and Pog-Np for subject A, in one measurement AN/FH for subject B, and in three measurements U1/FH, FMIA, and AN/FH for subject C. While demonstrating workability as a chairside tool and whilst there is a need for further refinement in measurement accuracy, this newly developed cephalometric system shows potential applicability, not only in the clinic as an auxiliary to or as a substitute for existing radiographic cephalometry, but also outside the clinic as an epidemiological tool.

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The regenerative capacity of viable cells remaining in cryopreserved vascular allografts is still unclear. Recently, the regenerating gene (Reg) has been documented to play an important role in various regenerating tissues. Here we show the possibility of Reg induction for the enhancement of cryopreserved vascular allograft viability. Cryopreserved rat aortae were isografted or allografted heterotopically. Fresh isografts were also tested. The transplants were retrieved 3, 6, 9, and 12 days after implantation and the intragraft Reg mRNA was measured by a real-time quantitative reverse transcriptional polymerase chain reaction method. Reg expression was not detected before implantation. Reg expression in cryopreserved isografts gradually increased after transplantation, whereas in fresh isografts or cryopreserved allografts it decreased over time after initial expression. Daily administration of 0.5 g/kg nicotinamide (an agent known to be a potent inducer of Reg) induced intragraft Reg mRNA in cryopreserved allografts (p < 0.05) accompanied by augmentation of the intragraft cell population. Daily administration of 0.5 mg/kg FK506 (an immunosuppressant) induced intragraft Reg mRNA both in cryopreserved isografts and allografts (p < 0.01). We conclude that Reg-inductive therapy shows promise as a novel strategy for enhancing the viability of vascular allografts. Moreover, FK506 may be involved in tissue regeneration as well as immunosuppression.

No abstract