Evaluation of healing of pressure ulcers through thermography: a preliminary study

Introduction Thermography is a surface thermal radiation measurement technique whose application has been expanding in the healthcare field. The unhealed wound is a serious public health problem because it intervenes in the quality of life of patients and may cause emotional and psychological losses. The wound temperature can provide quantitative data that allow for the healing process to be monitored. The aim of this study was to verify whether thermography can be used as a method to evaluate the healing of pressure ulcers. Methods Eight participants with sacral pressure ulcers were recruited and randomly divided into two groups: A (control) and B (experimental). Both groups received standard treatment for a period of four weeks, which consisted of a daily cleaning of the pressure ulcers with physiological saline (sodium chloride 0.9%) followed by an alginate hydrogel dressing. The group B received light-emitting diode (LED) phototherapy in addition to standard treatment, three times a week, yielding a total of 12 sessions. Photographs and thermograms of each pressure ulcer were obtained in all sessions in both groups. Results Pressure ulcers treated with LED phototherapy were healed. The pressure ulcer area of group B decreased over the 12 treatment sessions, whereas the pressure ulcer area of group A increased. The ulcer temperature of group B was higher than that of group A during the treatment (temperature difference up to 7.6%). Discussion The present study suggests a relationship between the temperature and area of pressure ulcers and proposes thermography as an adjunctive method for the evaluation of healing processes.

Determination of expander apparatus displacements and contact pressures on the mucosa using FEM modelling considering mandibular asymmetries.

This paper presents a method for prediction of forces and displacements in the expansion screw of a modified mandibular Schwarz appliance and the contact pressure distributions on the mucosa during malocclusions treatment. A 3D finite element biomechanical model of the complete mandible-mucosa-apparatus set was built using computerised tomographic images of a patient's mandible and constructive solid geometry by computer software. An iterative procedure was developed to handle a boundary condition that takes into account the mandibular asymmetries. The results showed asymmetries in the contact pressure distributions that indicated with precision the patient's malocclusion diagnosis. In vivo measurements of contact pressure using piezoelectric sensors agreed with the computational results. It was shown that the left and right ends of the expansion screw move differently with respect to the patient mandible, even though the expansion screw has an opening mechanism to ensure equal stretching at both ends. The contact pressures between the apparatus and the mucosa vary linearly with applied forces, which can simplify the analysis of the biomechanical behaviour of the expander mandible apparatus. The biomechanical modelling proposed in this paper can be a useful tool to improve malocclusions treatment, safely avoiding the use of forces acting on live structures beyond the biological tolerance, which could result in traumatic effects.

Measurement of thermophysical properties of human dentin: effect of open porosity.

UNLABELLED: In dentistry caries removal can be performed with rotatory instruments or high intensity laser. Both techniques can heat the tooth and harm the pulp. The literature review about the measurement of human dentin thermophysical properties revealed a great variation of the values obtained by several authors, and most of the studies are outdated. Most of these studies have not directly measured the thermal diffusivity of human dentin, and the reported values are calculated values based on measurements of conductivity, density and specific heat. OBJECTIVE: The aim of the present study was to measure human dentin thermal diffusivity, density, open porosity and specific heat, and then to calculate its thermal conductivity and analyze the influence of open porosity in these properties. METHOD: The methods used were: flash laser method for measuring thermal diffusivity, method of penetration and immersion with xylol for density and open porosity and differential scanning calorimetry for measuring specific heat. Calculated results of the thermal conductivity are shown as well. RESULT: Results of diffusivity, density, open porosity, specific heat and thermal conductivity of measurements performed on five samples are presented and compared with results of other authors. The open porosity of the samples varied between 1.11% and 3.08% of the sample volume, corresponding to densities ranging between 2090 and 2400 kg m(-3), thermal diffusivity: 0.199 and 0.265 x 10(-6)m2 s(-1), specific heat: 872.5 and 1181.0 J kg(-1)K(-1), thermal conductivity: 0.363 and 0.666 W m(-1)K(-1). CONCLUSION: It has been found that there exist a strong correlation between the open porosity of human dentin and its thermal conductivity and density. Both human dentin thermal conductivity and density decrease with the increasing of open porosity, with a confidence of at least 98% and 96.6%, respectively.