Effect of pressure on heat transport in polymers used in dentistry

✍ Scribed by Chen, R. Y. S. ;Barker, R. E.

• Publisher: John Wiley and Sons
• Year: 1972
• Tongue: English
• Weight: 293 KB
• Volume: 6
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/jbm.820060303

✦ Synopsis

The thermal properties of dental materials are important in certain aspects of tooth repair and the restoration of dental function. This is especially true for polymeric dental materials, for which low thermal conductivity is often considered an important asset. This paper contains a report on the surprisingly large effect that pressure (well with in the range encountered on the biting surfaces of teeth) can have on heat transfer in polymers that are widely used in dentistry. A sandwich type pressure-conductivity cell has been used to measure the thermal conductivity K of polystyrene, polymethyl methacrylate, polyethyl methacrylate, and poly-n-hutyl methacrylate. The measurements span the range -50 to 50°C and pressures up to 2000 bar. For the polymers mentioned (and many others) K a t a given temperature increases as pressure is increased.

Initial increases in pressure to several hundred bars may typically increase the over-all heat transfer coefficient by a factor of two or more. A t higher pressures, the relative slope ( d K / d p ) / K is typically about 10% per kilobar. Some comments are made about the thermal contact coefficient and the thermal diffusivity which are of more direct interest to dentists than K itself.