Measurement of Gingival Swelling from Dental Casts by Generation of a Moire Pattern with Laser Light

Abstract

The aim of the study was to develop a sensitive measuring method enabling direct evaluation of gingival swelling to be made as registered on dental casts. On two separate occasions, when different degrees of severity of gingival inflammation were present in the same subject, reversible hydrocolloid impressions were taken of the mandible. The casts obtained were located successively in identical three-dimensional relationships in a field of interference fringes generated by two intersecting beams of collimated helium-neon laser light, and were photographed. The evaluation of the moiré pattern obtained directly by superimposition of the two images of the surface studied indicated that a decrease in gingival height of 0.38 mm in the direction of the camera had occurred between the two occasions. The use of a computer-based image-processing system considerably improved the visibility of the pattern. The reproducibility of the impression technique, as well as the relocation and superimposing techniques, proved satisfactory at the moiré resolution used (0.19 mm). The method has potential application in clinical experimental research, and therefore warrants further evaluation.

New Trends in Dental Biomechanics with Photonics Technologies

“…Their findings were consistent with the hypothesis that within the dentin there are structural adaptations for transferring and minimizing stress. Wouters et al [53] developed a sensitive measuring method, based in Moiré fringe interferometry with a resolution of 0.19 mm, to enable the direct evaluation of gingival swelling.…”

Retractions of the gingival margins evaluated by holographic methods

“…(ii) Holography has a range of dentistry applications [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], including for the qualitative study of dental structures, the evaluation of elastic deformations of soldered gold joints, and the measurement of elastic deformation of prosthodontic appliances. It was also applied to evaluate tooth displacements, the centers of rotations of the teeth, the deformation of human skulls, the stress and strain in the periodontal ligament and alveolar bone after a certain force application -the latter aspects in orthodontics [9][10][11][13][14][15].…”

“…It was also applied to evaluate tooth displacements, the centers of rotations of the teeth, the deformation of human skulls, the stress and strain in the periodontal ligament and alveolar bone after a certain force application -the latter aspects in orthodontics [9][10][11][13][14][15].…”

“…This approach is based on several previous studies regarding the use of holograms in dentistry for the evaluation of tooth movements by superposing a cast and a hologram representing different time moments [13,14], for the direct evaluation of gingival swelling [11,12], and for the measurement of deformations and fractures in dental hard tissues or in composite material, as produced by internal stresses [10].…”

Analyzing spinal deformities by spatial data extracted from computer generated moiré images

“…Wouters et al used moiré phenomenon to examine gum swellings caused by dental implants. 1 Richard Smith et al applied it in the improvement of the dimensional accuracy of tooth implants. 2 In plastic surgery, Sungyeon Ahn et al developed a special grating to quantify the elasticity of human skin based on moiré strain analysis.…”