Survival of batch numbers within dental implants following incineration as an aid to identification.
(74/129)
Dental implants have become a popular choice of treatment in replacing individual lost teeth or entire dentitions. The physical properties of high corrosion resistance, high structural strength and high melting point, suggest the retention of intact implants following most physical assaults. As the implants are machine made, they lack the individualisation required for their use as identifiers of the deceased, however the Straumann Company (Waldenburg, Switzerland) has recently released information that within the chamber of their implants they have laser etched batch numbers. The number of implants with the same batch number varies from 24 to 2400. The purpose of this study was to ascertain if the batch number was still identifiable following intense heat exposure in a furnace. A Straumann Standard Plus 3.3 x 8 mm implant, with no healing cap nor abutment attached was incinerated to 1125 degrees Celsius. Another Straumann Standard Plus 3.3 x 8 mm implant was also incinerated in the same way as the first implant but with an abutment attached. The results indicated that the first implant had totally oxidised within the internal chamber whilst the second implant following the removal of the abutment revealed an intact identifiable batch number. If the companies constructing implants were to place individual serial numbers rather than batch numbers on these implants then the potential exists for a new approach to be established for the identification of the deceased. (+info)
Implant/abutment vertical misfit of one-piece cast frameworks made with different materials.
(75/129)
Comparison of the marginal fit of different coping materials and designs produced by computer aided manufacturing systems.
(76/129)
In this study, marginal adaptations of different copings fabricated with CAD/CAM or MAD/CAM were analysed. Celay and Zirkonzahn groups were fabricated by MAD/CAM, LAVA and DC-Zircon groups were fabricated by CAD/CAM. Casting metal copings were used as the control group. An implant abutment that was embedded in octagonal acrylic block was used to prepare the copings. Sixteen previously established points were marked and the measurements were performed with the stereomicroscope (at x 150). The marginal fit of the samples were evaluated by calculating the mean measurements of each 16 points. The statistical analysis was performed by Tukey multiple comparisons test at 95% confidence interval. The groups can be summarized as follows in terms of marginal gap, from the lowest to highest: LAVA (24.6 +/- 14.0 microm)+info)
Three-dimensional finite element analysis of posterior fiber-reinforced composite fixed partial denture Part 2: influence of fiber reinforcement on mesial and distal connectors.
(77/129)
The aim of this study was to evaluate the influence of connectors under two different loading conditions on displacement and stress distribution generated in isotropic hybrid composite fixed partial denture (C-FPD) and partially anisotropic fiber-reinforced hybrid composite fixed partial denture (FRC-FPD). To this end, two three-dimensional finite element (FE) models of three-unit FPD from mandibular second premolar to mandibular second molar - intended to replace the mandibular first molar - were developed. The two loading conditions employed were a vertical load of 629 N (applied to eight points on the occlusal surface) and a lateral load of 250 N (applied to three points of the pontic). The results suggested that the reinforcing fibers in FRC framework significantly improved the rigidity of the connectors against any twisting and bending moments induced by loading. Consequently, maximum principal stress and displacement generated in the connectors of FRC-FPD were significantly reduced because stresses generated by vertical and lateral loading were transferred to the reinforcing fibers. (+info)
Immediate implant loading following computer-guided surgery.
(78/129)