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To investigate the effect of laser densification parameters on the cross section geometry of the laser‐densified single line, and thus provide guidance for selecting the laser processing condition to obtain dense shapes with minimum processing defects.

A range of dental porcelain powder lines with small cross section areas (in the order of 1 × 1 mm²) were extruded from micro‐extruders and laser densified with the systematically changed peak laser power intensity, laser beam diameter, and ratio of the laser beam diameter to the width of the powder line.

The peak laser power intensity, laser beam diameter, and ratio of the laser beam diameter to the width of the powder line have substantial influence on the cross section geometry. The effects of these laser processing parameters can be explained in terms of minimization of surface energy in both solid and liquid states, volume shrinkage associated with densification, and temperature gradients present in the powder line during laser densification.

For the first time the cross section geometry of single powder lines in response to laser processing conditions has been systematically investigated, and the result offers guidance for obtaining dense shapes with minimum processing defects.

OUR new features of record and reminiscence appear to have been appreciated by our readers; and, as this number shows, we continue with increased pages and are endeavouring to extend our scope to meet every kind of library interest. There is an atmosphere, of change and, as some think, of crisis, in library matters, especially in those of the public library. The winter to which our minds turn in mid‐September is likely to be interesting and may bring decisions of various kinds. We hope to reflect them, and, as is our invariable custom, invite readers to use us to express their views as well as their experiences.

A three‐dimensional thermal finite element model including the effect of the powder‐to‐solid transition has been developed to investigate the transient temperature distribution and effects of substrate preheating during laser densification of dental powder bed for the layer‐by‐layer fabrication. The model encompasses the effects of the temperature‐ and porosity‐dependent thermal conduction and radiation as well as the temperature‐dependent natural convection. Substrate preheating is found to be important in preventing the formation of cracks in the dental porcelain body during laser densification. The simulation results are found to match the experiments very well.

A 3D finite element model was developed that simulates selective area laser deposition vapor infiltration (SALDVI) of silicon carbide. The model predicts the laser input power history needed to maintain constant surface temperature and the distribution of vapor deposited SiC within the powder bed as well as on the surface of the powder bed. The model considers a moving Gaussian distribution laser beam, temperature‐ and pore‐dependent thermal conductivity, specific heat and temperature‐dependent deposition rate. Furthermore, the model also includes closed‐loop control of the laser power to achieve a desired target processing temperature on the surface of the power bed. Effects of laser scanning rates have been investigated. The simulated solid fraction and SALD distributions are also consistent in the trend with the experimental data.

Commercial dental porcelain powder was deposited via slurry extrusion and laser densified to fabricate dental restorations in a multi‐material laser densification (MMLD) process.

A dental porcelain slurry was made from ball milled dental porcelain powders and extruded using the MMLD system. Extruded lines and rings were laser densified under different conditions in order to study how to build fully dense porcelain layers without warping and cracking during the MMLD process.

The geometric cross section of laser densified porcelain lines were dependent on laser processing parameters. Laser densified single ring showed no warping, and multiple layer body after laser densification showed cracks in the rings. The interface microstructure suggested good bonding between multiple layers. The mechanism to achieve single porcelain ring without warping and cracking is discussed. Alternate ways to build physical tooth layer by layer are proposed.

In the MMLD process, dental porcelain slurry was extruded from a human tooth computer file and laser densified to manufacture dental restorations based on solid freeform fabrication (SFF) principles. The understanding developed will pave the way for fabricating a physical dental restoration unit in the near future.