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Three-dimensional evaluation of mandibular deformation during mouth opening.
- Source :
-
International journal of computerized dentistry [Int J Comput Dent] 2019; Vol. 22 (1), pp. 21-27. - Publication Year :
- 2019
-
Abstract
- Aim: Deformation of the mandible presents a major challenge for many dentists, both in conventional prosthetic supraconstructions and in complex implant restorations. This study aimed to evaluate the three-dimensional (3D) deformation of the mandible in vivo with scannable impression material and an industrial optical scanner.<br />Materials and Methods: In the present study, 20 female and 20 male subjects were examined. In each case, two impressions were made with polyvinylsiloxane: one with the mouth slightly open, and a second with the mouth wide open. The impressions were digitized with an industrial optical scanner and transformed into a virtual model. The two corresponding models were digitally superimposed over all the teeth. Then, an individual local coordinate system was assigned to each individual tooth. Subsequently, a best-fit procedure was performed for each individual tooth. Finally, the open- and closed-mouth models were compared by calculating the differences and rotations in the individual axes. This procedure was performed individually for each tooth.<br />Results: The mean deviations in the x-, y-, and z-coordinates ranged from 0.011 mm at the canines to 0.232 mm at the molars. Larger discrepancies were observed in the female subjects than in the male subjects; however, these differences were not statistically significant.<br />Conclusion: The results demonstrated that the posterior region of the mandible deformed when the mouth was maintained in a wide-open position. Therefore, this position should be avoided when performing dental impressions. Moreover, potential negative consequences of this mandibular deformation should be taken into consideration when planning wide-span fixed dental restorations.
Details
- Language :
- English
- ISSN :
- 1463-4201
- Volume :
- 22
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- International journal of computerized dentistry
- Publication Type :
- Academic Journal
- Accession number :
- 30848251