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A comparison of three methods to evaluate the position of an artificial ear on the deficient side of the face from a three-dimensional surface scan of patients with hemifacial microsomia.
Int J Prosthodont. 2012 Mar-Apr; 25(2):160-5.IJ

Abstract

PURPOSE

Patients with hemifacial microsomia may have a missing ear on the deficient side of the face. The fabrication of an ear for such individuals usually has been accomplished by directly measuring the ear on the normal side to construct a prosthesis based on these dimensions, and the positioning has been, to a large extent, primarily operator-dependent. The aim of the present study was to compare three methods, developed from the identification of landmarks plotted on three-dimensional surface scans, to evaluate the position of an artificial ear on the deficient side of the face compared with the position of the natural ear on the normally developed side.

MATERIALS AND METHODS

Laser scans were undertaken of the faces of 14 subjects with hemifacial microsomia. Landmarks on the ear and face on the normal side were identified. Three methods of mirroring the normal ear on the deficient side of the face were investigated, which used either facial landmarks from the orbital area or a zero reference point generated from the intersection of three orthogonal planes on a frame of reference. To assess the methods, landmarks were identified on the ear situated on the normal side as well as on the face. These landmarks yielded paired dimensional measurements that could be compared between the normal and deficient sides. Mean differences and 95% confidence intervals were calculated.

RESULTS

It was possible to mirror the normal ear image on to the deficient side of the face using all three methods. Generally only small differences between the dimensional measurements on the normal and deficient sides were observed. However, two-way analysis of variance revealed statistically significant differences between the three methods (P = .005).

CONCLUSIONS

The method of mirroring using the outer canthi was found to result in the smallest dimensional differences between the anthropometric points on the ear and face between the normally developed and deficient sides. However, the effects of the deformity can result in limitations in relation to achieving a precise alignment of the ear to the facial tissues. This requires further study.

Authors+Show Affiliations

Department of Fixed and Removable Prosthodontics, Kings College, London, UK. trevor.coward@kcl.ac.ukNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

22371838

Citation

Coward, Trevor J., et al. "A Comparison of Three Methods to Evaluate the Position of an Artificial Ear On the Deficient Side of the Face From a Three-dimensional Surface Scan of Patients With Hemifacial Microsomia." The International Journal of Prosthodontics, vol. 25, no. 2, 2012, pp. 160-5.
Coward TJ, Watson RM, Richards R, et al. A comparison of three methods to evaluate the position of an artificial ear on the deficient side of the face from a three-dimensional surface scan of patients with hemifacial microsomia. Int J Prosthodont. 2012;25(2):160-5.
Coward, T. J., Watson, R. M., Richards, R., & Scott, B. J. (2012). A comparison of three methods to evaluate the position of an artificial ear on the deficient side of the face from a three-dimensional surface scan of patients with hemifacial microsomia. The International Journal of Prosthodontics, 25(2), 160-5.
Coward TJ, et al. A Comparison of Three Methods to Evaluate the Position of an Artificial Ear On the Deficient Side of the Face From a Three-dimensional Surface Scan of Patients With Hemifacial Microsomia. Int J Prosthodont. 2012 Mar-Apr;25(2):160-5. PubMed PMID: 22371838.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A comparison of three methods to evaluate the position of an artificial ear on the deficient side of the face from a three-dimensional surface scan of patients with hemifacial microsomia. AU - Coward,Trevor J, AU - Watson,Roger M, AU - Richards,Robin, AU - Scott,Brendan J J, PY - 2012/2/29/entrez PY - 2012/3/1/pubmed PY - 2012/6/1/medline SP - 160 EP - 5 JF - The International journal of prosthodontics JO - Int J Prosthodont VL - 25 IS - 2 N2 - PURPOSE: Patients with hemifacial microsomia may have a missing ear on the deficient side of the face. The fabrication of an ear for such individuals usually has been accomplished by directly measuring the ear on the normal side to construct a prosthesis based on these dimensions, and the positioning has been, to a large extent, primarily operator-dependent. The aim of the present study was to compare three methods, developed from the identification of landmarks plotted on three-dimensional surface scans, to evaluate the position of an artificial ear on the deficient side of the face compared with the position of the natural ear on the normally developed side. MATERIALS AND METHODS: Laser scans were undertaken of the faces of 14 subjects with hemifacial microsomia. Landmarks on the ear and face on the normal side were identified. Three methods of mirroring the normal ear on the deficient side of the face were investigated, which used either facial landmarks from the orbital area or a zero reference point generated from the intersection of three orthogonal planes on a frame of reference. To assess the methods, landmarks were identified on the ear situated on the normal side as well as on the face. These landmarks yielded paired dimensional measurements that could be compared between the normal and deficient sides. Mean differences and 95% confidence intervals were calculated. RESULTS: It was possible to mirror the normal ear image on to the deficient side of the face using all three methods. Generally only small differences between the dimensional measurements on the normal and deficient sides were observed. However, two-way analysis of variance revealed statistically significant differences between the three methods (P = .005). CONCLUSIONS: The method of mirroring using the outer canthi was found to result in the smallest dimensional differences between the anthropometric points on the ear and face between the normally developed and deficient sides. However, the effects of the deformity can result in limitations in relation to achieving a precise alignment of the ear to the facial tissues. This requires further study. SN - 0893-2174 UR - https://www.unboundmedicine.com/medline/citation/22371838/A_comparison_of_three_methods_to_evaluate_the_position_of_an_artificial_ear_on_the_deficient_side_of_the_face_from_a_three_dimensional_surface_scan_of_patients_with_hemifacial_microsomia_ L2 - http://www.diseaseinfosearch.org/result/9648 DB - PRIME DP - Unbound Medicine ER -