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Influence of maxillary obturator prostheses on facial morphology in patients with unilateral maxillary defects
Influence of maxillary obturator prostheses on facial morphology in patients with unilateral maxillary defects Soshi Hanawa, DDS, PhD,a Aki Kitaoka, DDS,b Shigeto Koyama, DDS, PhD,c and Keiichi Sasaki, DDS, PhDd Tohoku University Graduate School of Dentistry, Sendai, Japan Statement of problem. Facial asymmetry is prominent with individuals with unilateral bone resorption and can lead to decreased quality of life. Purpose. The purpose of this study was to investigate the influence of maxillary obturator prostheses on facial morphology of individuals with unilateral maxillary defects by using 3-dimensional digital stereophotogrammetry. Material and methods. The facial data of 8 participants with unilateral maxillary defects were acquired with a noncontact 3dimensional digitizer, both with and without maxillary prostheses. The mid-facial plane was established by overlapping an original facial image with its mirror image. Displacement at 18 measurement points, including 7 bilateral pairs, was compared between the 2 sides, with and without the prostheses. Asymmetry indices of these 7 pairs also were calculated. Multivariate repeated-measures ANOVA was used to determine differences. Results. Displacements of the lateral and inferior points at the ala of the nose were significantly greater on the defect side than on the normal side. The distances between the ideal and defect side points at the superior ala, the upper lip, and the angle of the mouth decreased significantly with the prosthesis. No significant differences were found in asymmetry indices, but the angle of the upper lip line to the mid-sagittal plane increased significantly with the prosthesis. Conclusions. The 3-dimensional analyzing method developed in this study can be useful in evaluating facial reconstruction with maxillary obturator prostheses with individuals with unilateral maxillary defects. The prostheses affect the region of the nasal ala, the upper lip, and the angles of the mouth. (J Prosthet Dent 2014;-:---)
Clinical Implications Asymmetry that results from a unilateral maxillary defect will not be improved if the individual is only fitted with a maxillary obturator prosthesis of conventional design. It will be necessary to develop new maxillary prosthesis casts to decrease the difference in the linear distances to less than 3 mm between the defect side points and their ideal points around the nose and lips. Oncologic surgery frequently results in facial asymmetry and deformity, and individuals may experience tooth loss; alveolar, maxillary, or mandibular bone resorption; or changes to the residual
ridge of the hard palate. In particular, facial deformity and asymmetry with those patients with extensive unilateral bone loss, where the facial soft tissues over the defect become recessed as a
result of the loss of lip and buccal support, can lead to a decrease in quality of life and psychological disorders.1-3 The facial clinimetric evaluation scale has been used to evaluate the
Presented at the biennial meeting of the International College of Prosthodontists, Turin, Italy, September 2013. Supported by a grant-in-aid for scientific research (no. 24592897) from the Ministry of Education, Culture, Sports, Science and Technology of Japan. a
Assistant Professor, Division of Advanced Prosthetic Dentistry. Graduate student, Division of Advanced Prosthetic Dentistry. c Associate Professor, Maxillofacial Prosthetics Clinic. d Dean, Tohoku University Graduate School of Dentistry; and Professor, Division of Advanced Prosthetic Dentistry. b
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Volume Most previous studies of facial morphology have used 2-dimensional data from digital photographs or sagittal plane projections of laser scans.5-8 However, a comprehensive and accurate assessment of the face should be performed with complex 3dimensional (3D) morphology. Hence, to evaluate quantitatively the effects of denture treatment on facial morphology, an objective 3D assessment of the face is needed. A number of reports used objective assessments to determine facial reconstruction success. Most of these aimed to evaluate changes in facial morphology in young participants during growth,9-12 before and after surgery and/ or after orthodontic treatment,13-17 and before and after surgery for the treatment of cleft lip and cleft palate.18-27 A few reports focused on changes in facial morphology with and without complete dentures.5,28,29 For instance, Kamashita et al5 investigated the relationship
quality of life of individuals with facial nerve paralysis, which usually is accompanied by facial asymmetry.1-3 The scale consists of 6 domains: facial movement, facial comfort, oral function, eye comfort, lacrimal control, and social function. The scores of individuals with facial nerve paralysis were found to be significantly lower than those of control participants in all domains.1 In particular, facial appearance is closely related to social function. In addition to restoring functions, such as mastication, deglutition, and speech, one of the key goals of prosthodontic treatment is to correct facial proportions, which is directly linked to improvement in quality of life and psychological disorders as well as to improved form and function.4 When dental prostheses are used to reconstruct the face, however, assessing facial morphology before and after treatment is imperative.
Table I.
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between the lip support provided by complete dentures and the lateral views of the facial appearance of patients with edentulism. Tartaglia et al8 also evaluated the morphologic changes to facial soft tissue with and without implantsupported prostheses. To our knowledge, no study has investigated facial soft tissue morphology of patients with unilateral maxillary defects by using a 3D approach. Thus, how a maxillary obturator prosthesis affects the face is currently unclear. By using an objective assessment of 3D digital stereophotogrammetry, the aim of the current study was to verify the hypothesis that maxillary obturator prostheses can compensate for facial deformity and asymmetry of patients with unilateral maxillary defects.
MATERIAL AND METHODS Eight individuals (6 men and 2 women; mean age, 69 years; range,
Participant profile information
Participant Age No. (y) Sex
Maxillary Missing Teeth
Defect Side
Aramany Class. No.a
Obturator Type
1
70
M
Right: central incisor; left: central incisor, lateral incisor, canine, first premolar, second premolar, first molar, second molar
Left
4
Hollow
2
69
M
Right: central incisor, lateral incisor, canine, first premolar, second premolar, first molar, second molar; left: central incisor, lateral incisor, canine, first premolar
Right
2
Hollow
3
61
M
Right: central incisor; left: central incisor, lateral incisor, canine, first premolar, second premolar, first molar, second molar
Left
4
Hollow
4
70
M
Right: central incisor, lateral incisor, canine, first premolar, second premolar, first molar
Right
2
Hollow
5
75
M
Right: central incisor, lateral incisor, canine, first premolar, second premolar, first molar, second molar; left: central incisor
Right
1
Hollow
6
76
M
Right: central incisor, lateral incisor, canine, first premolar, second premolar, first molar, second molar; left: central incisor
Right
2
Hollow
7
72
F
Left: central incisor, lateral incisor, canine, first premolar, second premolar, first molar, second molar
Left
1
Hollow
8
59
F
Left: first premolar, second premolar, first molar, second molar
Left
2
Hollow
References 27, 28. a Classes: 1, midline resection; 2, unilateral resection; 3, central resection; 4, bilateral resection.
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59-76 years) with unilateral maxillary defects and facial asymmetry after oncologic surgery and who wore welladapted conventional obturator prostheses participated in this study. The profiles of the participants, including age, sex, number and position of missing teeth, defect side, Aramany classification,30,31 and obturator type, are reported in Table I. The maxillary obturator prostheses were fabricated by making a closed tray impression with the border molding technique for each participant. Individual trays (Tray resin II; Shofu Inc) with modeling plastic impression compound (Impression tray compound; GC Corp) and polyvinyl siloxane impression material (Exahiflex; GC Corp) were used. The ethics committee of the Tohoku University Graduate School of Dentistry approved the study (approval no. 24-20). The participants provided their informed consent to participate in the study after receiving a full explanation of its purpose and methods. A skilled researcher (S. H.) marked a set of 20 soft tissue landmarks on each participant’s face with a skin marker, as outlined in Figure 1. The landmarks were marked while the participant was not wearing his or her maxillary obturator prostheses. The participant was placed in a seated position on a chair with the Frankfort plane parallel to the ground, with eyes open, lips closed naturally, and maxillary and mandibular teeth occluded at the intercuspal position with the tongue and perioral muscles relaxed. The 4 midline landmarks were pronasale (prn), subnasale (sn), labrale superius (ls), and labrale inferius (li). The 8 paired landmarks, with the normal side denoted as n- and the defect side as d-, were ectocanthion (ex: n-ex, d-ex), entocanthion (en: n-en, d-en), alare superius (als: n-als, d-als), alare (al: n-al, d-al), alare inferius (ali: n-ali, d-ali), cheilion (ch: n-ch, d-ch), christa philtri (cph: ncph, d-cph), and otobasion inferius (obi: n-obi, d-obi). For the paired landmarks, the obi pair was used to determine the reference planes. Three-dimensional surface morphologic and color data of the participants’
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1 Twenty facial landmarks were used as measurement points. Midline landmarks: prn, pronasale; sn, subnasale; ls, labrale superius; li, labrale inferius. Paired landmarks (normal side noted as n-, defect side as d-): n-ex, d-ex, ectocanthion; n-en, d-en, entocanthion; n-als, d-als, alare superius; n-al, d-al, alare; n-ali, d-ali, alare inferius; n-ch, d-ch, cheilion; n-cph, d-cph, christa philtri; n-obi, d-obi, otobasion inferius.
2 Noncontacting 3-dimensional digitizer used in this study, Danae 100SP, is equipped with 2 distantly positioned digital cameras. faces with and without their maxillary obturator prostheses in place were acquired by using a noncontact 3D
digitizer (Danae 100SP; NEC Engineering Ltd) (Fig. 2). The 3D digitizer contained a pair of projectors, light emitting
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Volume diode lamps, and digital cameras configured as a stereo pair to obtain 3D coordinates of the facial morphology. The 3D coordinates of the facial data were calculated within an accuracy of 0.18 mm by the sinusoidal grating projection with the phase shift method. During facial data acquisition, the participants were directed to sit motionlessly in a chair with an upright back and headrest. Facial data collection took 0.6 seconds. The 3D facial data were assessed with 3D scanning software (Rapidform2006; INUS Technology Inc and Rapidform Inc). One researcher (S. H.) digitally plotted the marked facial landmarks on enlarged facial images on a computer screen. Twenty measurement points were set for each participant, including 8 bilateral pairs and 7 measurement lines, defined as the lines that connect the measurement points of the 7 bilateral pairs. The accuracy of digital plotting on the computer screen was verified before the experiment. Point plotting was repeated 10 times at 30-second intervals, with the accuracy of plotting defined as the standard deviation of the distances from the median point of 10 recorded points as 3D coordinate calculations. The resulting accuracy of plotting was 0.19 mm. The smallest significant difference values were set for each analysis in light of the accuracies of the digitizer (0.18 mm) and the plotting (0.19 mm). For the analyses of the measurement points and lines in the 3D coordinate system, 3 reference planes perpendicular to each other were set to acquire 3D facial casts of the participants (Fig. 3). The mid-sagittal plane was defined as a plane that passes through 3 arbitrary points along the borderline generated by overlapping the original facial image with its mirror image by using 3D scanning software as previously reported.32,33 The transverse plane was defined as a plane that passes through 3 points; n-ali, n-obi, and the projected point of n-obi onto the midsagittal plane. Finally, the coronal plane was defined as the plane that passes through n-obi and runs perpendicular to the mid-sagittal and transverse planes.
The normal direction of the mid-sagittal plane was defined as the X-axis direction, transverse as Y, and coronal as Z. The 3D coordinates (X, Y, Z) of the measurement points were then calculated. Displacements of the measurement points on each participant’s face when wearing the obturator prosthesis were measured with respect to the 3D coordinates of the measurement points without the prosthesis. The displacements of 7 of the 8 bilateral pairs (by using the obi pair as a reference) were compared between the normal and defect sides. For each of the 7 pairs, the ideal point was defined as the point obtained by inverting the normal side onto the defect side along the midsagittal plane. The distances between the ideal point and the defect side point were then measured. The ideal X coordinates were defined as the projected points of the midline landmarks on the
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mid-sagittal plane, in which the X coordinate was equal to 0. The distances between the ideal coordinates with and without the prosthesis inserted were then measured. Asymmetry indices for the 7 paired measurement points and the angles between the measurement lines and the mid-sagittal plane were calculated. The mean values obtained for all the participants were used in the following statistical analyses. Multivariate repeated-measures ANOVA was used to determine the differences in the displacements of each 3D coordinate (X, Y, Z) of all the measurement points, distances between 3D coordinates, and linear distances between ideal and defect side points, asymmetry indices of the paired measurement points, and angles of measurement lines to the mid-sagittal reference plane with versus without the maxillary prosthesis. If the results of the Mauchly test of
3 Three reference planes, perpendicular to each other, were set to create 3-dimensional facial casts. Normal direction of mid-sagittal plane was defined as X axis direction, transverse as Y, and coronal as Z. A, Mid-sagittal plane. B, Transverse plane. C, Coronal plane.
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sphericity were not statistically significant, then sphericity was assumed. If the results of the test were statistically significant, then the Greenhouse-Geisser correction was used for nonspherical data. The test also was used to compare the linear displacement of the measurement points between the normal and defect sides. Further, the 2-way interactions between any 2 measurement points in all combinations and prostheses on the displacements of each 3D coordinate of all measurement points, on the distances between the ideal and defect side points, and on the asymmetry indices and angles of the measurement lines to the mid-sagittal reference plane were analyzed. Results with P<.05 were regarded as significant. Statistical analyses were performed with statistical software (SPSS v17.0; SPSS Inc).
RESULTS The 3D coordinates of the measurement points on both sides of the face were compared with and without the prosthesis inserted (Table II). All of the midline measurement points, ls, prn, sn, and li, could be located on the defect side without the prosthesis. With the prosthesis in place, prn approached the mid-sagittal plane (X axis) by 0.14 mm and n-ch by 2.22 mm, whereas the sn landmark moved 1.15 mm laterally. Furthermore, d-ali was displaced forward (Z axis) by 5.97 mm, d-cph by 3.62 mm, and sn by 1.55 mm. All of these displacements were determined to be significant. None of the points significantly shifted vertically (Y axis). The linear displacements of d-al (3.36 mm) and d-ali (6.59 mm) with and without the prosthesis were 1.55 and 4.48 mm longer than those of n-al (1.81 mm) and n-ali (2.11 mm), differences also were determined to be significant. The 2-way interactions between any 2 measurement points in all combinations and the prostheses on the displacements of each 3D coordinate of all measurement points are shown in Table III. The significant interactions on the displacements of each 3D coordinate of the
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5 measurement points were found predominantly in the measurement points that had shifted significantly with the prosthesis in place. The distance between the d-als, d-ch, and d-cph points and their respective ideal points decreased significantly when participants wore the prostheses, and the same tendency was observed for d-ali (Table IV). The d-als and d-cph points approached their ideal points by moving forward significantly when the participants were wearing the prostheses. In the vertical and transverse projections, none of the defect points moved significantly closer to their ideal points when the prosthesis was inserted. The interactions between measurement points and prostheses on distances between the ideal and defect side points are shown in Table V. Most of the significant interactions on the distances between the ideal and defect side points were observed in the measurement points, which had approached their ideal points significantly with the prostheses. No significant differences were found in the asymmetry indices. However, the asymmetry index for the cph landmark increased by 8.74% with the prosthesis. The angle associated with the cph landmark significantly increased by 7.94 degrees with the prosthesis (Table VI). The interactions between measurement points and prostheses on the asymmetry indices and angles of measurement lines to the mid-sagittal reference plane are shown in Table VII. No significant interaction was found in the asymmetry indices. The significant interaction was found only in the angle associated with the cph. Wearing the obturator prostheses restored facial morphology around the ala of the nose, the upper lip, and the angle of the mouth on the defect side by changing the position of d-als, dcph, and d-ch to become more symmetrical with the normal side.
DISCUSSION Soft tissue facial morphology can be measured noninvasively in several ways.
Noncontacting optical instruments (eg, laser scanners, stereophotogrammetric digitizers) and contacting instruments (eg, electromagnetic digitizers) are currently used to measure and evaluate the patient’s face in dentistry.5,8-29,32,33 In this study, the participant’s natural appearance was captured by instructing him or her to keep the eyes open, by using halogen lamps as a light source, and by minimizing the influence of body motion by using a short acquisition time. Data acquisition of the entire face required only 1 shot, because the Danae 100SP noncontact 3D digitizer used in this study is equipped with 2 distantly positioned digital cameras, thus decreasing the burden on the participant. In recent years, 3D evaluation of facial morphology has quickly outpaced 2-dimensional evaluations because of rapid advances in computer graphics. The reference for facial analysis now uses a plane as opposed to a line. Hartmann et al32 determined a mid-sagittal reference plane by superimposing the 3D facial image of a normal individual onto its mirror image. Nkenke et al,20 Bilwatsch et al,21 and Stauber et al22 also determined the mid-sagittal reference plane by using similar methods in patients with a cleft lip and cleft palate. Benz et al33 described that the closest point on the superimposed mirror data for each point of an original data set could be determined by bisecting the distances between corresponding pairs of data points, thus establishing a plane of symmetry. In this study, the midsagittal reference plane was determined based on these reports.32,33 Significant displacement of prn, sn, d-al, n-ch, and d-cph was observed when the participants wore their maxillary obturator prostheses, with sn, d-ali, and d-cph shifting forward significantly. Because 7 of the 8 participants had lost the anterior teeth on the defect side, the artificial teeth and the contour of the denture base of the prosthesis altered the shape of the nose and the upper lip on that side. Kamashita et al5 reported changes in lip support with and
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Table II.
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Displacement of measurement points
X (mm), mean (CLs)a Measure. Without Point Pros
With Pros
P
Y (mm), mean (CLs)b Without Pros
With Pros
P
Z (mm), mean (CLs) Without Pros
With Pros
P
LD (mm) Mean (CLs) Displacement
n-ex
44.3 (42.8, 45.9)
44.3 (42.7, 45.9)
.913
46.5 (45.0, 48.1)
46.5 (45.3, 47.8)
.993
80.5 (75.4, 85.6)
80.1 (74.2, 85.9)
.709
2.8 (1.7, 3.9)
d-ex
44.0 (45.4, 42.6)
44.2 (45.5, 42.9)
.330
47.4 (46.3, 48.5)
47.7 (46.5, 48.9)
.386
80.3 (74.8, 85.8)
79.7 (75.3, 84.1)
.488
2.2 (1.3, 3.0)
n-en
20.1 (18.1, 22.1)
19.8 (18.2, 21.4)
.591
47.8 (45.8, 49.7)
47.7 (45.8, 49.5)
.762
83.4 (77.8, 88.9)
82.8 (77.0, 88.6)
.178
1.7 (1.1, 2.3)
d-en
19.3 (20.9, 17.6)
20.4 (22.4, 18.3)
.096
47.7 (45.9, 49.5)
47.9 (46.3, 49.4)
.634
83.2 (77.5, 88.8)
82.9 (77.9, 87.8)
.520
2.3 (1.5, 3.0)
n-als
14.8 (12.7, 16.9)
14.7 (13.0, 16.3)
.806
16.2 (14.2, 18.2)
15.8 (13.8, 17.8)
.290
94.5 (89.5, 99.6)
94.5 (89.5, 99.6)
.992
3.8 (2.6, 4.9)
d-als
15.1 (16.6, 13.6)
15.2 (17.4, 13.1)
.834
18.7 (17.3, 20.0)
18.3 (16.3, 20.4)
.665
93.1 (88.1, 98.1)
94.3 (90.3, 98.2)
.296
3.4 (2.1, 4.6)
n-al
20.9 (19.5, 22.4)
20.7 (19.2, 22.1)
.378
7.2 (6.3, 8.1)
6.8 (5.7, 8.0)
.321
86.5 (83.7, 89.4)
86.5 (83.0, 89.9)
.909
1.8 (1.2, 2.4)
d-al
20.9 (22.1, 19.6)
21.8 (22.7, 20.8)
.098
11.4 (9.1, 13.7)
11.5 (8.7, 14.2)
.859
85.3 (81.6, 89.0)
86.5 (83.2, 89.9)
.252
3.4 (2.4, 4.3)
n-ali
17.3 (15.9, 18.8)
17.6 (16.0, 19.1)
.603
0.0 (0.0, 0.0)
0.3 (0.5, 1.0)
.500
88.8 (85.0, 92.6)
88.4 (84.6, 92.2)
.525
2.1 (1.4, 2.8)
d-ali
17.0 (18.7, 15.4)
18.2 (19.3, 17.0)
.051
3.9 (1.9, 5.9)
4.4 (1.8, 7.0)
.415
84.2 (81.4, 86.9)
90.1 (85.6, 94.6)
.007d
6.6 (3.8, 9.4)
n-ch
26.4 (23.8, 29.0)
24.2 (21.7, 26.6)
.042d
27.0 (28.3, 25.7)
26.7 (28.5, 24.9)
.472
77.4 (75.8, 79.0)
78.9 (76.0, 81.7)
.289
4.3 (2.5, 6.2)
d-ch
25.8 (27.9, 23.8)
26.2 (28.2, 24.3)
.606
19.9 (22.5, 17.2)
20.6 (24.4, 16.8)
.448
75.4 (71.5, 79.2)
76.4 (72.9, 79.8)
.351
4.1 (2.9, 5.2)
n-cph
4.7 (2.9, 6.5)
3.5 (2.1, 5.0)
.226
17.1 (19.7, 14.5)
17.6 (20.1, 15.1)
.311
94.7 (92.0, 97.4)
95.7 (92.7, 98.6)
.061
3.0 (2.1, 3.9)
d-cph
8.9 (10.4, 7.3)
9.1 (10.3, 7.8)
.658
15.1 (17.6, 12.6)
15.7 (18.6, 12.8)
.311
90.7 (87.5, 94.0)
94.4 (91.6, 97.1)
.004d
4.2 (2.7, 5.7)
ls
2.7 (4.4, 1.0)
3.0 (5.0, 1.0)
.156
18.1 (20.4, 15.7)
18.1 (20.8, 15.5)
.927
93.9 (90.9, 96.8)
95.4 (92.8, 98.0)
.113
3.3 (2.3, 4.3)
prn
1.0 (2.3, 0.3)
0.8 (1.9, 0.2)
.032d
10.2 (7.2, 13.1)
9.3 (6.5, 12.1)
.213
108.1 (102.9, 113.3)
108.2 (103.1, 113.2)
.794
2.2 (1.4, 3.0)
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P .213
.174
.650
.040c
.017c
.193
.847
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Table II.
7 (Continued) Displacement of measurement points
X (mm), mean (CLs) Measure. Without Point Pros
With Pros
a
Y (mm), mean (CLs) Without Pros
P
With Pros
b
P
LD (mm) Mean (CLs)
Z (mm), mean (CLs) Without Pros
With Pros
Displacement
P
wn
0.6 (1.5, 0.3)
1.8 (2.4, 1.1)
.022
0.8 (2.2, 0.7)
0.9 (2.5, 0.6)
.623
91.5 (87.9, 95.1)
93.1 (89.3, 96.8)
.027
li
1.8 (4.0, 0.4)
1.6 (3.1, 0.1)
.537
31.6 (34.5, 28.6)
31.3 (34.3, 28.2)
.704
92.9 (89.7, 96.0)
93.7 (89.9, 97.4)
.358
d
d
P
2.7 (2.0, 3.4) 3.5 (2.5, 4.4)
CL, confidence limit; Pros, prosthesis; LD, linear distance;. n, normal side; ex, ectocanthion; d, defect side; en, entocanthion; als, alare superius; al, alare; ali, alare inferius; ch, cheilion; cph, christa philtri; ls, labrale superius; prn, pronasale; sn, subnasale; li, labrale inferius. a Negative values in X coordinates indicate measurement points were located in defect side. b Negative values in Y coordinates indicate below horizontal plane. c Significant difference in paired measurement points between normal and defect sides. d Significant difference in measurement points with vs without prosthesis.
without complete dentures with reference to changes in landmarks projected onto the sagittal plane. They reported that the degree of lip support changes not only the lip contour but also the form of the nasal base
and the appearance of the labiomental sulcus. Fanibunda et al28 also reported the forward shift in both the upper and lower lips after the insertion of complete dentures as a dominant effect of maxillary dentures.
The results of the current study agree with those of previous studies. In contrast, no significant vertical shift was found for any of the landmarks in this study. Similarly, Kamashita et al5 reported that the vertical
Orthogonal array of interactions between measurement points and prostheses on displacement of measurement points (X / Y / Z)
Table III.
Measure. Point
n-en n-als n-al n-ali n-cph n-ch d-ex d-en d-als d-al d-ali d-cph d-ch prn
n-ex
-/-/- -/-/- -/-/- -/-/- - / - / - -/-/- -/-/- -/-/- -/-/- -/-/- -/-/* - / - / * -/-/- -/-/- - / - / - */-/- -/-/-
n-en
-/-/- -/-/- -/-/- - / - / - -/-/- -/-/- -/-/- -/-/- -/-/- -/-/* - / - / * -/-/- */-/- */-/* -/-/ - -/-/-
n-als
-/-/- -/-/- - / - / - -/*/- -/-/- -/-/- -/-/- -/-/- */-/* - / - / - -/-/- -/-/- */-/- -/-/ - -/-/-
sn
ls
li
n-al
-/-/- - / - / - -/-/- -/-/- -/-/- -/-/- -/-/- */-/* - / - / * -/-/- */-/- */-/* -/-/ - -/-/-
n-ali
- / - / - */-/- -/-/- -/-/- -/-/- -/-/- -/-/* - / - / * -/-/- -/-/- -/-/* -/-/- -/-/-
n-cph
-/-/- -/-/- */-/- -/-/- */-/- -/-/* - / - / * -/-/- -/-/- */-/- -/-/- -/-/-
n-ch
-/-/- */-/- -/-/- */-/- */-/* - / - / - -/-/- */-/- */-/- */-/- -/-/-
d-ex
-/-/- -/-/- -/-/- -/-/* -/-/* -/-/- -/-/- -/- /- -/-/- -/-/-
d-en
-/-/- -/-/- -/-/* -/-/* -/-/- -/-/- -/-/* -/-/- -/-/-
d-als
-/-/- -/-/* - / - / - -/*/- -/-/- - / - / - -/-/- -/-/-
d-al
-/-/* -/-/- -/-/--/-/- -/-/- -/-/--/-/-
d-ali
- / - / - -/-/* -/-/* -/-/* -/-/* -/-/*
d-cph d-ch prn
-/-/- -/-/* - / - / - -/-/* -/-/* -/-/- -/-/- -/-/--/-/-/-/* -/*/- -/-/-
sn
-/-/--/-/-
ls
-/-/-
n, normal side; en, entocanthion; als, alare superius; al, alare; ali, alare inferius; cph; christa philtri; ch, cheilion; d, defect side; ex, ectocanthion; prn, pronasale; sn, subnasale; ls, labrale superius; li, labrale inferius; -, no significant interaction between measurement points and prostheses; *, significant interaction between measurement points and prostheses.
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Table IV.
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Distances between ideal and defect side points
X (mm), mean (CLs)
Y (mm), mean (CLs)
Without P Pros
With Pros
Z (mm), mean (CLs)
Without P Pros
With Pros
Linear Distance (mm) mean (CLs)
Measure. Without Point Pros
With Pros
d-ex
1.8 (0.4, 3.2)
1.2 .194 (0.3, 2.2)
1.3 (0.8, 1.9)
1.7 .222 (1.1, 2.3)
1.2 (0.4, 1.9)
1.5 .638 (0.2, 2.7)
2.8 (1.4, 4.2)
3.1 .655 (2.1, 4.1)
d-en
1.4 (0.3, 2.5)
1.6 .827 (0.7, 2.4)
0.9 (0.2, 1.5)
1.3 .120 (0.4, 2.2)
1.1 (0.5, 1.6)
1.0 .872 (0.3, 1.7)
2.4 (1.5, 3.3)
2.4 .973 (1.0, 3.7)
d-als
1.6 (0.8, 2.4)
1.0 .213 (0.4, 1.5)
3.4 (1.5, 5.2)
3.4 .861 (1.5, 5.4)
3.6 (2.6, 4.6)
1.7 .003a (1.0, 2.3)
5.6 (4.0, 7.2)
4.2 .030a (2.4, 6.1)
d-al
1.6 (0.7, 2.5)
1.5 .852 (0.8, 2.2)
4.2 4.3 (1.5, (1.8, 6.5) 7.1)
.859
2.1 (0.9, 3.3)
2.4 .715 (1.3, 3.5)
5.6 (3.5, 7.6)
5.6 .965 (3.0, 8.2)
d-ali
1.8 (0.9, 2.7)
1.8 .988 (0.8, 2.8)
3.9 (1.9, 5.9)
4.4 .358 (1.9, 7.0)
4.7 (2.8, 6.5)
2.6 .092 (1.5, 3.7)
6.7 (4.4, 9.1)
6.1 .438 (4.1, 8.2)
d-ch
3.5 (2.1, 5.0)
2.8 .219 (1.7, 3.9)
7.2 (5.2, 9.1)
6.6 .660 (3.9, 9.4)
3.5 (1.0, 5.9)
2.8 .493 (1.2, 4.5)
9.4 (7.1, 11.6)
8.1 (5.1, .044a 11.0)
d-cph
4.6 (2.4, 6.9)
4.5 .791 2.0 (1.2, (2.7, 7.1) 2.8)
1.8 .542 (0.6, 3.0)
4.0 (2.6, 5.4)
0.8 (0.5, .003a 1.1)
6.8 (4.6, 9.0)
5.3 .038a (3.0, 7.7)
ls
2.7 3.2 (1.5, .213 (1.1, 4.4) 5.0)
prn
1.6 (0.6, 2.5)
1.1 .375 (0.2, 2.1)
sn
1.2 (0.7, 1.7)
1.7 .195 (1.1, 2.4)
li
2.7 (1.0, 4.3)
2.0 .294 (0.7, 3.2)
P
Without Pros
With Pros
P
CL, confidence limit; Pros, prosthesis; d, defect side; ex, ectocanthion; en, entocanthion; als, alare superius; al, alare; ali, alare inferius; ch, cheilion; cph, christa philtri; ls, labrale superius; prn, pronasale; sn, subnasale; li, labrale inferius. a Significant difference in measurement points with vs without prosthesis.
position of the ch was not affected by the degree of lip support when the mandibular positions were kept constant. Analysis of the results of the present study indicates that the soft tissue close to the denture base of maxillary prostheses, such as cph and ali, shifts anteriorly, and that points in the middle distance from the denture base, such as ch and prn, shift laterally. On the normal side, only n-ch moved significantly with insertion of the maxillary prostheses. A previous study with the same analytical method as this one determined the asymmetry indices of the ex, al, and ch points on the right and left sides of normal individuals as well as the angles between the mid-sagittal
plane and the measurement lines that connect these 3 right- and left-side point pairs.34 That study reported asymmetry indices of 2.15% for ex, 3.95% for al, and 2.01% for ch. The angle of ex was 88.4 degrees, al was 87.3 degrees, and ch was 87.9 degrees. In the present study, the asymmetry indices among unilateral maxillary defect participants without a maxillary prosthesis was 2.07% for ex, 3.78% for al, and 6.52% for ch. With the prosthesis, the indices were 0.87% for ex, 4.36% for al, and 5.36% for ch. The angle without the prosthesis was 88.1 degrees for ex, 82.6 degrees for al, and 82.8 degrees for ch. With the prosthesis, the angle of ex was 87.9 degrees, al was 81.9 degrees and ch 83.8 degrees.
The Journal of Prosthetic Dentistry
Asymmetry indices of ex and al among the participants with unilateral maxillary defects were rarely different from those of the unaffected individuals in the previous study. However, the asymmetry index of ch among participants with unilateral maxillary defects was 3% to 5% higher than that of normal participants. No significant difference was found in the angle of the measurement line for ex to the midsagittal plane between the participants with maxillary defect and unaffected individuals, but the angles of the lines for al and ch were 4 to 6 degrees smaller among the participants with unilateral maxillary defects, regardless of whether or not the maxillary prosthesis was in place. In other words, these findings
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Orthogonal array of interactions between measurement points and prostheses on distances between ideal and defect side points (X / Y / Z)
Table V.
Measure. Point n-en n-als n-al n-ali n-cph n-ch
d-ex d-en d-als d-al d-ali d-cph d-ch prn sn ls li
n-ex
-/-/- -/-/* -/-/- -/-/- */-/- -/-/- -/-/- -/-/- -/-/* -/-/- -/-/- -/-/* -/-/-
-
-
-
-
n-en
-/-/* -/-/- -/-/- -/-/* -/-/- -/-/- -/-/- -/-/* -/-/- -/-/- -/-/* -/-/-
-
-
-
-
n-als
-/-/- -/-/- -/-/* -/-/* -/-/- -/-/* */-/- -/-/- -/-/- -/-/- -/-/-
-
-
-
-
n-al
-/-/- -/-/- -/-/- -/-/- -/-/- -/-/* -/-/- -/-/- -/-/* -/-/-
-
*
-
-
n-ali
-/-/- -/-/- -/-/- -/-/- -/-/- -/-/- -/-/- -/-/* -/-/-
-
-
-
-
-/-/- */-/- -/-/- -/-/* -/-/- -/-/- -/-/* -/-/-
-
-
-
-
n-cph n-ch
-/-/- -/-/- -/-/* -/-/- -/-/- -/-/* -/-/*
-
-
-
-
d-ex
-/-/- -/-/* -/-/- -/-/- -/-/* -/-/-
-
-
*
-
d-en
-/-/* -/-/- -/-/- -/-/* -/-/-
-
-
-
-
d-als
-/-/* -/-/- -/-/- -/-/-
-
-
-
-
d-al
-/-/- -/-/* -/-/-
-
-
-
-
d-ali
-/-/- -/-/-
-
-
-
-
-/-/-
-
-
-
-
-
-
-
-
-
-
-
-
-
d-cph d-ch prn sn ls
-
n, normal side; en, entocanthion; als, alare superius; ali, alare inferius; cph, christa philtri; ch, cheilion; d, defect side; ex, ectocanthion; al, alare; prn, pronasale; sn, subnasale; ls, labrale superius; li, labrale inferius; -, no significant interaction between measurement points and prostheses; *, significant interaction between measurement points and prostheses.
indicate that asymmetrical faces with a unilateral maxillary defect cannot be made completely symmetrical with the use of maxillary obturator prostheses of conventional design.
Table VI.
In an eye-tracking study, MeyerMarcotty et al26 found that an observer’s gaze is distracted to the nose and mouth area of a face with a unilateral cleft lip and palate. Moreover, individuals
with unilateral cleft lip and/or palate themselves focused greater attention on their anomalous features compared with participants without cleft lip and/or palate. Loss of teeth, loss of maxillary bone,
Asymmetry indices and angles of measurement lines to mid-sagittal reference plane
Asymmetry Index (%), mean (CLs)a Measurement Point or Line
Without Pros
Angle (degree), mean (CLs)b
With Pros
P
Without Pros
With Pros
P
ex
2.1 (0.5, 3.7)
0.9 (0.4, 1.4)
.185
88.1 (87.4, 88.9)
87.9 (86.9, 88.8)
.152
en
3.5 (0.7, 6.3)
4.4 (2.5, 6.3)
.561
87.4 (86.7, 88.2)
87.5 (86.7, 88.3)
.762
als
5.2 (2.6, 7.7)
6.1 (3.6, 8.5)
.649
83.0 (80.7, 85.3)
82.4 (78.7, 86.2)
.587
al
3.8 (1.6, 5.9)
4.4 (2.5, 6.2)
.684
82.6 (79.7, 85.4)
81.9 (78.6, 85.1)
.457
ali
5.2 (2.6, 7.8)
5.1 (2.5, 7.7)
.936
78.8 (74.9, 82.8)
79.5 (75.9, 83.1)
.314
ch
6.5 (4.1, 9.0)
5.4 (1.6, 9.1)
.677
82.8 (80.2, 85.5)
83.8 (81.7, 85.8)
.128
cph
37.3 (15.4, 59.3)
46.1 (27.2, 64.9)
.309
69.4 (61.3, 77.5)
77.4 (75.9, 83.1)
.012c
CL, confidence limit; Pros, prosthesis; ex, ectocanthion; en, entocanthion; als, alare superius; al, alare; ali, alare inferius; ch, cheilion; cph, christa philtri. a Asymmetry index: j D－N j 100/( D þ N ); D is the distance from defect side measurement point to mid-sagittal plane, N is the distance from normal side point to mid-sagittal plane. b Angle: acute angle between mid-sagittal plane and measurement line that connects measurement point of the normal side to corresponding point of defect side. c Significant difference in measurement points with vs without prosthesis.
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Volume Orthogonal array of interactions between measurement points and prostheses on asymmetry indices and angles of measurement lines to mid-sagittal reference plane
Table VII.
Measurement Point or Line ex en als al
Asymmetry Index
Angle
4.
5.
en als al ali cph ch en als al ali cph ch -
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
ali cph
-
-
-
-
*
-
-
-
-
*
-
-
-
-
*
-
-
*
-
*
-
6.
7.
*
en, entocanthion; als, alare superius; al, alare; ali, alare inferius; cph, christa philtri; ch, cheilion; -, no significant interaction between measurement points and prostheses; *, significant interaction between measurement points and prostheses; ex, ectocanthion.
8.
of life. Changes in facial morphology that result from arbitrary alterations of the flange form of the maxillary prosthesis that do not affect oral function should be investigated. The flange form can affect facial morphology of individuals with maxillary defects, and its limitations will be determined by future research.
9.
loss and/or atrophy of orofacial muscles, loss and/or atrophy of adipose tissue, and cicatricial contracture, depending on the approach, can result from oncologic surgery for maxillary cancer. These postoperative morphologic abnormalities affect maxillofacial morphology, and, because individuals with unilateral maxillary defects also have anomalous features, the observer’s gaze may also focus on the asymmetrical region. Eugene et al35 determined the degree of facial asymmetry required to trigger a conscious perception of an observer by using a simulated model of facial paralysis. They reported that at least 3 mm of facial asymmetry at the oral commissure, brow, or both was required before participants detected the asymmetry. As shown in Table IV, the linear distances between ex, en, ls, prn, sn, and li on the defect side and their ideal points were approximately 3 mm or less, regardless of whether the prosthesis was in place. However, als, al, ali, ch, and cph were 4.23 to 9.39 mm (more than 3 mm) from their ideal points. To restore facial symmetry of patients with unilateral maxillary defects, new types of maxillary prostheses must be developed to decrease the linear distances to less than 3 mm between the defect side points and their ideal points around the nose and lips; new maxillary prostheses may need to be generated to improve patient quality
CONCLUSIONS Within the limitations of this study, the following conclusions were drawn. The maxillary obturator prosthesis significantly changed the facial morphology of the tip of the nose, the inferior nose, the nasal ala, the upper lip on the defect side, and the angles of the mouth on both sides horizontally but did not alter these areas vertically. The maxillary obturator prosthesis improves facial symmetry in the region of the nasal ala, the upper lip, and the angle of the mouth on the defect side of individuals with unilateral maxillary defects.
10.
11.
12.
13.
14.
15.
REFERENCES 1. Kahn JB, Gliklich RE, Boyev KP, Stewart MG, Metson RB, McKenna MJ. Validation of a patient-graded instrument for facial nerve paralysis: the FaCE scale. Laryngoscope 2001;111:387-98. 2. Mehta RP, Hadlock TA. Botulinum toxin and quality of life in patients with facial paralysis. Arch Facial Plast Surg 2008;10:84-7. 3. Ng JH, Ngo RY. The use of the facial clinimetric evaluation scale as a patient-based
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grading system in Bell’s palsy. Laryngoscope 2013;123:1256-60. Dover MS, Worrollo S. Prosthetic rehabilitation of the facial area. Curr Opin Otolaryngol Head Neck Surg 2002;10:129-33. Kamashita Y, Kamada Y, Kawahata N, Nagaoka E. Influence of lip support on the soft-tissue profile of complete denture wearers. J Oral Rehabil 2006;33:102-9. Suzuki A, Suzuki T, Hayakawa I. Influence of occlusal vertical dimension and labiolingual position of artificial anterior teeth in complete dentures on the facial appearance. Prosthodont Res Pract 2006;5:44-51. Lee MS, Chung DH, Lee JW, Cha KS. Assessing soft-tissue characteristics of facial asymmetry with photographs. Am J Orthod Dentofacial Orthop 2010;138:23-31. Tartaglia GM, Dolci C, Sidequersky FV, Ferrario VF, Sforza C. Soft tissue facial morphometry before and after total oral rehabilitation with implant-supported prostheses. J Craniofac Surg 2012;23: 1610-4. Kau CH, Richmond S. Three-dimensional analysis of facial morphology surface changes in untreated children from 12 to 14 years of age. Am J Orthod Dentofacial Orthop 2008;134:751-60. Tolleson SR, Kau CH, Lee RP, English JD, Harila V, Pirttiniemi P, et al. 3-D analysis of facial asymmetry in children with hip dysplasia. Angle Orthod 2010;80:519-24. Primozic J, Perinetti G, Zhurov A, Richmond S, Ovsenik M. Assessment of facial asymmetry in growing subjects with a threedimensional laser scanning system. Orthod Craniofac Res 2012;15:237-44. Primozic J, Perinetti G, Richmond S, Ovsenik M. Three-dimensional evaluation of facial asymmetry in association with unilateral functional crossbite in the primary, early, and late mixed dentition phases. Angle Orthod 2013;83:253-8. Wettstein R, Kalbermatten DF, Rieger UM, Schumacher R, Dagorov P, Pierer G. Laser surface scanning analysis in reconstructive rhytidectomy. Aesthetic Plast Surg 2006;30: 637-40. Schwenzer-Zimmerer K, Chaitidis D, BergBoerner I, Krol Z, Kovacs L, Schwenzer NF, et al. Quantitative 3D soft tissue analysis of symmetry prior to and after unilateral cleft lip repair compared with non-cleft persons (performed in Cambodia). J Craniomaxillofac Surg 2008;36:431-8. Bozic M, Kau CH, Richmond S, Ovsenik M, Hren NI. Novel method of 3-dimensional soft-tissue analysis for Class III patients. Am J Orthod Dentofacial Orthop 2010;138: 758-69. Verzé L, Bianchi FA, Schellino E, Ramieri G. Soft tissue changes after orthodontic surgical correction of jaws asymmetry evaluated by three-dimensional surface laser scanner. J Craniofac Surg 2012;23:1448-52. Yuan L, Shen G, Wu Y, Jiang L, Yang Z, Liu J, et al. Three-dimensional analysis of soft tissue changes in full-face view after surgical correction of skeletal class III malocclusion. J Craniofac Surg 2013;24:725-30.
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18. Duffy S, Noar JH, Evans RD, Sanders R. Three-dimensional analysis of the child cleft face. Cleft Palate Craniofac J 2000;37: 137-44. 19. Sforza C, Peretta R, Grandi G, Ferronato G, Ferrario VF. Soft tissue facial volumes and shape in skeletal Class III patients before and after orthognathic surgery treatment. J Plast Reconstr Aesthet Surg 2007;60:130-8. 20. Nkenke E, Lehner B, Kramer M, Haeusler G, Benz S, Schuster M, et al. Determination of facial symmetry in unilateral cleft lip and palate patients from three-dimensional data: technical report and assessment of measurement errors. Cleft Palate Craniofac J 2006;43:129-37. 21. Bilwatsch S, Kramer M, Haeusler G, Schuster M, Wurm J, Vairaktaris E, et al. Nasolabial symmetry following TennisonRandall lip repair: a three-dimensional approach in 10-year-old patients with unilateral clefts of lip, alveolus and palate. J Craniomaxillofac Surg 2006;34:253-62. 22. Stauber I, Vairaktaris E, Holst A, Schuster M, Hirschfelder U, Neukam FW, et al. Threedimensional analysis of facial symmetry in cleft lip and palate patients using optical surface data. J Orofac Orthop 2008;69: 268-82. 23. Meyer-Marcotty P, Stellzig-Eisenhauer A. Dentofacial self-perception and social perception of adults with unilateral cleft lip and palate. J Orofac Orthop 2009;70: 224-36.
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11 24. Meyer-Marcotty P, Alpers GW, Gerdes AB, Stellzig-Eisenhauer A. Impact of facial asymmetry in visual perception: a 3-dimensional data analysis. Am J Orthod Dentofacial Orthop 2010;137:168.e1-8; discussion 168-9. 25. Meyer-Marcotty P, Kochel J, Boehm H, Linz C, Klammert U, Stellzig-Eisenhauer A. Face perception in patients with unilateral cleft lip and palate and patients with severe class III malocclusion compared to controls. J Craniomaxillofac Surg 2011;39:158-63. 26. Meyer-Marcotty P, Gerdes AB, StellzigEisenhauer A, Alpers GW. Visual face perception of adults with unilateral cleft lip and palate in comparison to controls: an eye tracking study. Cleft Palate Craniofac J 2011;48:210-6. 27. Djordjevic J, Lewis BM, Donaghy CE, Zhurov AI, Knox J, Hunter L, et al. Facial shape and asymmetry in 5-year-old children with repaired unilateral cleft lip and/or palate: an exploratory study using laser scanning. Eur J Orthod 2012. 28. Fanibunda KB, Allcock GC, Thomason JM. Changes in the facial profile following insertion of complete dentures. Eur J Prosthodont Restor Dent 2002;10:143-9. 29. Ushijima M, Kamashita Y, Nishi Y, Nagaoka E. Changes in lip forms on threedimensional images with alteration of lip support and/or occlusal vertical dimension in complete denture wearers. J Prosthodont Res 2013;57:113-21. 30. Aramany MA. Basic principles of obturator design for partially edentulous patients. Part I: classification. J Prosthet Dent 1978;40: 554-7.
31. Aramany MA. Basic principles of obturator design for partially edentulous patients. Part II: design principles. J Prosthet Dent 1978;40: 656-62. 32. Hartmann J, Meyer-Marcotty P, Benz M, Häusler G, Stellzig-Eisenhauer A. Reliability of a method for computing facial symmetry plane and degree of asymmetry based on 3Ddata. J Orofac Orthop 2007;68:477-90. 33. Benz M, Laboureux X, Maier T, Nkenke E, Seeger S, Neukam FW, et al. The symmetry of faces. In: Greiner G, Niemann H, Ertl T, Girod B, Seidel HP, editors. Vision, modeling, and visualization. Amsterdam: IOS Press; 2002. p. 332-9. 34. Hanawa S, Koyama S, Sato N, Sasaki K. Validity of mid-facial reference planes for evaluating asymmetry face [in Japanese]. Maxillofacial prosthetics 2009;32:53-60. 35. Eugene AC, Tarik YF, Lisa EI, Patrick JB. Threshold of visual perception of facial asymmetry in a facial paralysis model. Arch Facial Plast Surg 2011;13:14-9. Corresponding author: Dr Soshi Hanawa Division of Advanced Prosthetic Dentistry Tohoku University Graduate School of Dentistry 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 JAPAN E-mail: [email protected] Copyright ª 2014 by the Editorial Council for The Journal of Prosthetic Dentistry.
Clinical Implications Asymmetry that results from a unilateral maxillary defect will not be improved if the individual is only fitted with a maxillary obturator prosthesis of conventional design. It will be necessary to develop new maxillary prosthesis casts to decrease the difference in the linear distances to less than 3 mm between the defect side points and their ideal points around the nose and lips. Oncologic surgery frequently results in facial asymmetry and deformity, and individuals may experience tooth loss; alveolar, maxillary, or mandibular bone resorption; or changes to the residual
ridge of the hard palate. In particular, facial deformity and asymmetry with those patients with extensive unilateral bone loss, where the facial soft tissues over the defect become recessed as a
result of the loss of lip and buccal support, can lead to a decrease in quality of life and psychological disorders.1-3 The facial clinimetric evaluation scale has been used to evaluate the
Presented at the biennial meeting of the International College of Prosthodontists, Turin, Italy, September 2013. Supported by a grant-in-aid for scientific research (no. 24592897) from the Ministry of Education, Culture, Sports, Science and Technology of Japan. a
Assistant Professor, Division of Advanced Prosthetic Dentistry. Graduate student, Division of Advanced Prosthetic Dentistry. c Associate Professor, Maxillofacial Prosthetics Clinic. d Dean, Tohoku University Graduate School of Dentistry; and Professor, Division of Advanced Prosthetic Dentistry. b
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Volume Most previous studies of facial morphology have used 2-dimensional data from digital photographs or sagittal plane projections of laser scans.5-8 However, a comprehensive and accurate assessment of the face should be performed with complex 3dimensional (3D) morphology. Hence, to evaluate quantitatively the effects of denture treatment on facial morphology, an objective 3D assessment of the face is needed. A number of reports used objective assessments to determine facial reconstruction success. Most of these aimed to evaluate changes in facial morphology in young participants during growth,9-12 before and after surgery and/ or after orthodontic treatment,13-17 and before and after surgery for the treatment of cleft lip and cleft palate.18-27 A few reports focused on changes in facial morphology with and without complete dentures.5,28,29 For instance, Kamashita et al5 investigated the relationship
quality of life of individuals with facial nerve paralysis, which usually is accompanied by facial asymmetry.1-3 The scale consists of 6 domains: facial movement, facial comfort, oral function, eye comfort, lacrimal control, and social function. The scores of individuals with facial nerve paralysis were found to be significantly lower than those of control participants in all domains.1 In particular, facial appearance is closely related to social function. In addition to restoring functions, such as mastication, deglutition, and speech, one of the key goals of prosthodontic treatment is to correct facial proportions, which is directly linked to improvement in quality of life and psychological disorders as well as to improved form and function.4 When dental prostheses are used to reconstruct the face, however, assessing facial morphology before and after treatment is imperative.
Table I.
-
Issue
-
between the lip support provided by complete dentures and the lateral views of the facial appearance of patients with edentulism. Tartaglia et al8 also evaluated the morphologic changes to facial soft tissue with and without implantsupported prostheses. To our knowledge, no study has investigated facial soft tissue morphology of patients with unilateral maxillary defects by using a 3D approach. Thus, how a maxillary obturator prosthesis affects the face is currently unclear. By using an objective assessment of 3D digital stereophotogrammetry, the aim of the current study was to verify the hypothesis that maxillary obturator prostheses can compensate for facial deformity and asymmetry of patients with unilateral maxillary defects.
MATERIAL AND METHODS Eight individuals (6 men and 2 women; mean age, 69 years; range,
Participant profile information
Participant Age No. (y) Sex
Maxillary Missing Teeth
Defect Side
Aramany Class. No.a
Obturator Type
1
70
M
Right: central incisor; left: central incisor, lateral incisor, canine, first premolar, second premolar, first molar, second molar
Left
4
Hollow
2
69
M
Right: central incisor, lateral incisor, canine, first premolar, second premolar, first molar, second molar; left: central incisor, lateral incisor, canine, first premolar
Right
2
Hollow
3
61
M
Right: central incisor; left: central incisor, lateral incisor, canine, first premolar, second premolar, first molar, second molar
Left
4
Hollow
4
70
M
Right: central incisor, lateral incisor, canine, first premolar, second premolar, first molar
Right
2
Hollow
5
75
M
Right: central incisor, lateral incisor, canine, first premolar, second premolar, first molar, second molar; left: central incisor
Right
1
Hollow
6
76
M
Right: central incisor, lateral incisor, canine, first premolar, second premolar, first molar, second molar; left: central incisor
Right
2
Hollow
7
72
F
Left: central incisor, lateral incisor, canine, first premolar, second premolar, first molar, second molar
Left
1
Hollow
8
59
F
Left: first premolar, second premolar, first molar, second molar
Left
2
Hollow
References 27, 28. a Classes: 1, midline resection; 2, unilateral resection; 3, central resection; 4, bilateral resection.
The Journal of Prosthetic Dentistry
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59-76 years) with unilateral maxillary defects and facial asymmetry after oncologic surgery and who wore welladapted conventional obturator prostheses participated in this study. The profiles of the participants, including age, sex, number and position of missing teeth, defect side, Aramany classification,30,31 and obturator type, are reported in Table I. The maxillary obturator prostheses were fabricated by making a closed tray impression with the border molding technique for each participant. Individual trays (Tray resin II; Shofu Inc) with modeling plastic impression compound (Impression tray compound; GC Corp) and polyvinyl siloxane impression material (Exahiflex; GC Corp) were used. The ethics committee of the Tohoku University Graduate School of Dentistry approved the study (approval no. 24-20). The participants provided their informed consent to participate in the study after receiving a full explanation of its purpose and methods. A skilled researcher (S. H.) marked a set of 20 soft tissue landmarks on each participant’s face with a skin marker, as outlined in Figure 1. The landmarks were marked while the participant was not wearing his or her maxillary obturator prostheses. The participant was placed in a seated position on a chair with the Frankfort plane parallel to the ground, with eyes open, lips closed naturally, and maxillary and mandibular teeth occluded at the intercuspal position with the tongue and perioral muscles relaxed. The 4 midline landmarks were pronasale (prn), subnasale (sn), labrale superius (ls), and labrale inferius (li). The 8 paired landmarks, with the normal side denoted as n- and the defect side as d-, were ectocanthion (ex: n-ex, d-ex), entocanthion (en: n-en, d-en), alare superius (als: n-als, d-als), alare (al: n-al, d-al), alare inferius (ali: n-ali, d-ali), cheilion (ch: n-ch, d-ch), christa philtri (cph: ncph, d-cph), and otobasion inferius (obi: n-obi, d-obi). For the paired landmarks, the obi pair was used to determine the reference planes. Three-dimensional surface morphologic and color data of the participants’
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1 Twenty facial landmarks were used as measurement points. Midline landmarks: prn, pronasale; sn, subnasale; ls, labrale superius; li, labrale inferius. Paired landmarks (normal side noted as n-, defect side as d-): n-ex, d-ex, ectocanthion; n-en, d-en, entocanthion; n-als, d-als, alare superius; n-al, d-al, alare; n-ali, d-ali, alare inferius; n-ch, d-ch, cheilion; n-cph, d-cph, christa philtri; n-obi, d-obi, otobasion inferius.
2 Noncontacting 3-dimensional digitizer used in this study, Danae 100SP, is equipped with 2 distantly positioned digital cameras. faces with and without their maxillary obturator prostheses in place were acquired by using a noncontact 3D
digitizer (Danae 100SP; NEC Engineering Ltd) (Fig. 2). The 3D digitizer contained a pair of projectors, light emitting
4
Volume diode lamps, and digital cameras configured as a stereo pair to obtain 3D coordinates of the facial morphology. The 3D coordinates of the facial data were calculated within an accuracy of 0.18 mm by the sinusoidal grating projection with the phase shift method. During facial data acquisition, the participants were directed to sit motionlessly in a chair with an upright back and headrest. Facial data collection took 0.6 seconds. The 3D facial data were assessed with 3D scanning software (Rapidform2006; INUS Technology Inc and Rapidform Inc). One researcher (S. H.) digitally plotted the marked facial landmarks on enlarged facial images on a computer screen. Twenty measurement points were set for each participant, including 8 bilateral pairs and 7 measurement lines, defined as the lines that connect the measurement points of the 7 bilateral pairs. The accuracy of digital plotting on the computer screen was verified before the experiment. Point plotting was repeated 10 times at 30-second intervals, with the accuracy of plotting defined as the standard deviation of the distances from the median point of 10 recorded points as 3D coordinate calculations. The resulting accuracy of plotting was 0.19 mm. The smallest significant difference values were set for each analysis in light of the accuracies of the digitizer (0.18 mm) and the plotting (0.19 mm). For the analyses of the measurement points and lines in the 3D coordinate system, 3 reference planes perpendicular to each other were set to acquire 3D facial casts of the participants (Fig. 3). The mid-sagittal plane was defined as a plane that passes through 3 arbitrary points along the borderline generated by overlapping the original facial image with its mirror image by using 3D scanning software as previously reported.32,33 The transverse plane was defined as a plane that passes through 3 points; n-ali, n-obi, and the projected point of n-obi onto the midsagittal plane. Finally, the coronal plane was defined as the plane that passes through n-obi and runs perpendicular to the mid-sagittal and transverse planes.
The normal direction of the mid-sagittal plane was defined as the X-axis direction, transverse as Y, and coronal as Z. The 3D coordinates (X, Y, Z) of the measurement points were then calculated. Displacements of the measurement points on each participant’s face when wearing the obturator prosthesis were measured with respect to the 3D coordinates of the measurement points without the prosthesis. The displacements of 7 of the 8 bilateral pairs (by using the obi pair as a reference) were compared between the normal and defect sides. For each of the 7 pairs, the ideal point was defined as the point obtained by inverting the normal side onto the defect side along the midsagittal plane. The distances between the ideal point and the defect side point were then measured. The ideal X coordinates were defined as the projected points of the midline landmarks on the
The Journal of Prosthetic Dentistry
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mid-sagittal plane, in which the X coordinate was equal to 0. The distances between the ideal coordinates with and without the prosthesis inserted were then measured. Asymmetry indices for the 7 paired measurement points and the angles between the measurement lines and the mid-sagittal plane were calculated. The mean values obtained for all the participants were used in the following statistical analyses. Multivariate repeated-measures ANOVA was used to determine the differences in the displacements of each 3D coordinate (X, Y, Z) of all the measurement points, distances between 3D coordinates, and linear distances between ideal and defect side points, asymmetry indices of the paired measurement points, and angles of measurement lines to the mid-sagittal reference plane with versus without the maxillary prosthesis. If the results of the Mauchly test of
3 Three reference planes, perpendicular to each other, were set to create 3-dimensional facial casts. Normal direction of mid-sagittal plane was defined as X axis direction, transverse as Y, and coronal as Z. A, Mid-sagittal plane. B, Transverse plane. C, Coronal plane.
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sphericity were not statistically significant, then sphericity was assumed. If the results of the test were statistically significant, then the Greenhouse-Geisser correction was used for nonspherical data. The test also was used to compare the linear displacement of the measurement points between the normal and defect sides. Further, the 2-way interactions between any 2 measurement points in all combinations and prostheses on the displacements of each 3D coordinate of all measurement points, on the distances between the ideal and defect side points, and on the asymmetry indices and angles of the measurement lines to the mid-sagittal reference plane were analyzed. Results with P<.05 were regarded as significant. Statistical analyses were performed with statistical software (SPSS v17.0; SPSS Inc).
RESULTS The 3D coordinates of the measurement points on both sides of the face were compared with and without the prosthesis inserted (Table II). All of the midline measurement points, ls, prn, sn, and li, could be located on the defect side without the prosthesis. With the prosthesis in place, prn approached the mid-sagittal plane (X axis) by 0.14 mm and n-ch by 2.22 mm, whereas the sn landmark moved 1.15 mm laterally. Furthermore, d-ali was displaced forward (Z axis) by 5.97 mm, d-cph by 3.62 mm, and sn by 1.55 mm. All of these displacements were determined to be significant. None of the points significantly shifted vertically (Y axis). The linear displacements of d-al (3.36 mm) and d-ali (6.59 mm) with and without the prosthesis were 1.55 and 4.48 mm longer than those of n-al (1.81 mm) and n-ali (2.11 mm), differences also were determined to be significant. The 2-way interactions between any 2 measurement points in all combinations and the prostheses on the displacements of each 3D coordinate of all measurement points are shown in Table III. The significant interactions on the displacements of each 3D coordinate of the
Hanawa et al
5 measurement points were found predominantly in the measurement points that had shifted significantly with the prosthesis in place. The distance between the d-als, d-ch, and d-cph points and their respective ideal points decreased significantly when participants wore the prostheses, and the same tendency was observed for d-ali (Table IV). The d-als and d-cph points approached their ideal points by moving forward significantly when the participants were wearing the prostheses. In the vertical and transverse projections, none of the defect points moved significantly closer to their ideal points when the prosthesis was inserted. The interactions between measurement points and prostheses on distances between the ideal and defect side points are shown in Table V. Most of the significant interactions on the distances between the ideal and defect side points were observed in the measurement points, which had approached their ideal points significantly with the prostheses. No significant differences were found in the asymmetry indices. However, the asymmetry index for the cph landmark increased by 8.74% with the prosthesis. The angle associated with the cph landmark significantly increased by 7.94 degrees with the prosthesis (Table VI). The interactions between measurement points and prostheses on the asymmetry indices and angles of measurement lines to the mid-sagittal reference plane are shown in Table VII. No significant interaction was found in the asymmetry indices. The significant interaction was found only in the angle associated with the cph. Wearing the obturator prostheses restored facial morphology around the ala of the nose, the upper lip, and the angle of the mouth on the defect side by changing the position of d-als, dcph, and d-ch to become more symmetrical with the normal side.
DISCUSSION Soft tissue facial morphology can be measured noninvasively in several ways.
Noncontacting optical instruments (eg, laser scanners, stereophotogrammetric digitizers) and contacting instruments (eg, electromagnetic digitizers) are currently used to measure and evaluate the patient’s face in dentistry.5,8-29,32,33 In this study, the participant’s natural appearance was captured by instructing him or her to keep the eyes open, by using halogen lamps as a light source, and by minimizing the influence of body motion by using a short acquisition time. Data acquisition of the entire face required only 1 shot, because the Danae 100SP noncontact 3D digitizer used in this study is equipped with 2 distantly positioned digital cameras, thus decreasing the burden on the participant. In recent years, 3D evaluation of facial morphology has quickly outpaced 2-dimensional evaluations because of rapid advances in computer graphics. The reference for facial analysis now uses a plane as opposed to a line. Hartmann et al32 determined a mid-sagittal reference plane by superimposing the 3D facial image of a normal individual onto its mirror image. Nkenke et al,20 Bilwatsch et al,21 and Stauber et al22 also determined the mid-sagittal reference plane by using similar methods in patients with a cleft lip and cleft palate. Benz et al33 described that the closest point on the superimposed mirror data for each point of an original data set could be determined by bisecting the distances between corresponding pairs of data points, thus establishing a plane of symmetry. In this study, the midsagittal reference plane was determined based on these reports.32,33 Significant displacement of prn, sn, d-al, n-ch, and d-cph was observed when the participants wore their maxillary obturator prostheses, with sn, d-ali, and d-cph shifting forward significantly. Because 7 of the 8 participants had lost the anterior teeth on the defect side, the artificial teeth and the contour of the denture base of the prosthesis altered the shape of the nose and the upper lip on that side. Kamashita et al5 reported changes in lip support with and
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Table II.
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Issue
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Displacement of measurement points
X (mm), mean (CLs)a Measure. Without Point Pros
With Pros
P
Y (mm), mean (CLs)b Without Pros
With Pros
P
Z (mm), mean (CLs) Without Pros
With Pros
P
LD (mm) Mean (CLs) Displacement
n-ex
44.3 (42.8, 45.9)
44.3 (42.7, 45.9)
.913
46.5 (45.0, 48.1)
46.5 (45.3, 47.8)
.993
80.5 (75.4, 85.6)
80.1 (74.2, 85.9)
.709
2.8 (1.7, 3.9)
d-ex
44.0 (45.4, 42.6)
44.2 (45.5, 42.9)
.330
47.4 (46.3, 48.5)
47.7 (46.5, 48.9)
.386
80.3 (74.8, 85.8)
79.7 (75.3, 84.1)
.488
2.2 (1.3, 3.0)
n-en
20.1 (18.1, 22.1)
19.8 (18.2, 21.4)
.591
47.8 (45.8, 49.7)
47.7 (45.8, 49.5)
.762
83.4 (77.8, 88.9)
82.8 (77.0, 88.6)
.178
1.7 (1.1, 2.3)
d-en
19.3 (20.9, 17.6)
20.4 (22.4, 18.3)
.096
47.7 (45.9, 49.5)
47.9 (46.3, 49.4)
.634
83.2 (77.5, 88.8)
82.9 (77.9, 87.8)
.520
2.3 (1.5, 3.0)
n-als
14.8 (12.7, 16.9)
14.7 (13.0, 16.3)
.806
16.2 (14.2, 18.2)
15.8 (13.8, 17.8)
.290
94.5 (89.5, 99.6)
94.5 (89.5, 99.6)
.992
3.8 (2.6, 4.9)
d-als
15.1 (16.6, 13.6)
15.2 (17.4, 13.1)
.834
18.7 (17.3, 20.0)
18.3 (16.3, 20.4)
.665
93.1 (88.1, 98.1)
94.3 (90.3, 98.2)
.296
3.4 (2.1, 4.6)
n-al
20.9 (19.5, 22.4)
20.7 (19.2, 22.1)
.378
7.2 (6.3, 8.1)
6.8 (5.7, 8.0)
.321
86.5 (83.7, 89.4)
86.5 (83.0, 89.9)
.909
1.8 (1.2, 2.4)
d-al
20.9 (22.1, 19.6)
21.8 (22.7, 20.8)
.098
11.4 (9.1, 13.7)
11.5 (8.7, 14.2)
.859
85.3 (81.6, 89.0)
86.5 (83.2, 89.9)
.252
3.4 (2.4, 4.3)
n-ali
17.3 (15.9, 18.8)
17.6 (16.0, 19.1)
.603
0.0 (0.0, 0.0)
0.3 (0.5, 1.0)
.500
88.8 (85.0, 92.6)
88.4 (84.6, 92.2)
.525
2.1 (1.4, 2.8)
d-ali
17.0 (18.7, 15.4)
18.2 (19.3, 17.0)
.051
3.9 (1.9, 5.9)
4.4 (1.8, 7.0)
.415
84.2 (81.4, 86.9)
90.1 (85.6, 94.6)
.007d
6.6 (3.8, 9.4)
n-ch
26.4 (23.8, 29.0)
24.2 (21.7, 26.6)
.042d
27.0 (28.3, 25.7)
26.7 (28.5, 24.9)
.472
77.4 (75.8, 79.0)
78.9 (76.0, 81.7)
.289
4.3 (2.5, 6.2)
d-ch
25.8 (27.9, 23.8)
26.2 (28.2, 24.3)
.606
19.9 (22.5, 17.2)
20.6 (24.4, 16.8)
.448
75.4 (71.5, 79.2)
76.4 (72.9, 79.8)
.351
4.1 (2.9, 5.2)
n-cph
4.7 (2.9, 6.5)
3.5 (2.1, 5.0)
.226
17.1 (19.7, 14.5)
17.6 (20.1, 15.1)
.311
94.7 (92.0, 97.4)
95.7 (92.7, 98.6)
.061
3.0 (2.1, 3.9)
d-cph
8.9 (10.4, 7.3)
9.1 (10.3, 7.8)
.658
15.1 (17.6, 12.6)
15.7 (18.6, 12.8)
.311
90.7 (87.5, 94.0)
94.4 (91.6, 97.1)
.004d
4.2 (2.7, 5.7)
ls
2.7 (4.4, 1.0)
3.0 (5.0, 1.0)
.156
18.1 (20.4, 15.7)
18.1 (20.8, 15.5)
.927
93.9 (90.9, 96.8)
95.4 (92.8, 98.0)
.113
3.3 (2.3, 4.3)
prn
1.0 (2.3, 0.3)
0.8 (1.9, 0.2)
.032d
10.2 (7.2, 13.1)
9.3 (6.5, 12.1)
.213
108.1 (102.9, 113.3)
108.2 (103.1, 113.2)
.794
2.2 (1.4, 3.0)
The Journal of Prosthetic Dentistry
P .213
.174
.650
.040c
.017c
.193
.847
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Table II.
7 (Continued) Displacement of measurement points
X (mm), mean (CLs) Measure. Without Point Pros
With Pros
a
Y (mm), mean (CLs) Without Pros
P
With Pros
b
P
LD (mm) Mean (CLs)
Z (mm), mean (CLs) Without Pros
With Pros
Displacement
P
wn
0.6 (1.5, 0.3)
1.8 (2.4, 1.1)
.022
0.8 (2.2, 0.7)
0.9 (2.5, 0.6)
.623
91.5 (87.9, 95.1)
93.1 (89.3, 96.8)
.027
li
1.8 (4.0, 0.4)
1.6 (3.1, 0.1)
.537
31.6 (34.5, 28.6)
31.3 (34.3, 28.2)
.704
92.9 (89.7, 96.0)
93.7 (89.9, 97.4)
.358
d
d
P
2.7 (2.0, 3.4) 3.5 (2.5, 4.4)
CL, confidence limit; Pros, prosthesis; LD, linear distance;. n, normal side; ex, ectocanthion; d, defect side; en, entocanthion; als, alare superius; al, alare; ali, alare inferius; ch, cheilion; cph, christa philtri; ls, labrale superius; prn, pronasale; sn, subnasale; li, labrale inferius. a Negative values in X coordinates indicate measurement points were located in defect side. b Negative values in Y coordinates indicate below horizontal plane. c Significant difference in paired measurement points between normal and defect sides. d Significant difference in measurement points with vs without prosthesis.
without complete dentures with reference to changes in landmarks projected onto the sagittal plane. They reported that the degree of lip support changes not only the lip contour but also the form of the nasal base
and the appearance of the labiomental sulcus. Fanibunda et al28 also reported the forward shift in both the upper and lower lips after the insertion of complete dentures as a dominant effect of maxillary dentures.
The results of the current study agree with those of previous studies. In contrast, no significant vertical shift was found for any of the landmarks in this study. Similarly, Kamashita et al5 reported that the vertical
Orthogonal array of interactions between measurement points and prostheses on displacement of measurement points (X / Y / Z)
Table III.
Measure. Point
n-en n-als n-al n-ali n-cph n-ch d-ex d-en d-als d-al d-ali d-cph d-ch prn
n-ex
-/-/- -/-/- -/-/- -/-/- - / - / - -/-/- -/-/- -/-/- -/-/- -/-/- -/-/* - / - / * -/-/- -/-/- - / - / - */-/- -/-/-
n-en
-/-/- -/-/- -/-/- - / - / - -/-/- -/-/- -/-/- -/-/- -/-/- -/-/* - / - / * -/-/- */-/- */-/* -/-/ - -/-/-
n-als
-/-/- -/-/- - / - / - -/*/- -/-/- -/-/- -/-/- -/-/- */-/* - / - / - -/-/- -/-/- */-/- -/-/ - -/-/-
sn
ls
li
n-al
-/-/- - / - / - -/-/- -/-/- -/-/- -/-/- -/-/- */-/* - / - / * -/-/- */-/- */-/* -/-/ - -/-/-
n-ali
- / - / - */-/- -/-/- -/-/- -/-/- -/-/- -/-/* - / - / * -/-/- -/-/- -/-/* -/-/- -/-/-
n-cph
-/-/- -/-/- */-/- -/-/- */-/- -/-/* - / - / * -/-/- -/-/- */-/- -/-/- -/-/-
n-ch
-/-/- */-/- -/-/- */-/- */-/* - / - / - -/-/- */-/- */-/- */-/- -/-/-
d-ex
-/-/- -/-/- -/-/- -/-/* -/-/* -/-/- -/-/- -/- /- -/-/- -/-/-
d-en
-/-/- -/-/- -/-/* -/-/* -/-/- -/-/- -/-/* -/-/- -/-/-
d-als
-/-/- -/-/* - / - / - -/*/- -/-/- - / - / - -/-/- -/-/-
d-al
-/-/* -/-/- -/-/--/-/- -/-/- -/-/--/-/-
d-ali
- / - / - -/-/* -/-/* -/-/* -/-/* -/-/*
d-cph d-ch prn
-/-/- -/-/* - / - / - -/-/* -/-/* -/-/- -/-/- -/-/--/-/-/-/* -/*/- -/-/-
sn
-/-/--/-/-
ls
-/-/-
n, normal side; en, entocanthion; als, alare superius; al, alare; ali, alare inferius; cph; christa philtri; ch, cheilion; d, defect side; ex, ectocanthion; prn, pronasale; sn, subnasale; ls, labrale superius; li, labrale inferius; -, no significant interaction between measurement points and prostheses; *, significant interaction between measurement points and prostheses.
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Table IV.
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Issue
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Distances between ideal and defect side points
X (mm), mean (CLs)
Y (mm), mean (CLs)
Without P Pros
With Pros
Z (mm), mean (CLs)
Without P Pros
With Pros
Linear Distance (mm) mean (CLs)
Measure. Without Point Pros
With Pros
d-ex
1.8 (0.4, 3.2)
1.2 .194 (0.3, 2.2)
1.3 (0.8, 1.9)
1.7 .222 (1.1, 2.3)
1.2 (0.4, 1.9)
1.5 .638 (0.2, 2.7)
2.8 (1.4, 4.2)
3.1 .655 (2.1, 4.1)
d-en
1.4 (0.3, 2.5)
1.6 .827 (0.7, 2.4)
0.9 (0.2, 1.5)
1.3 .120 (0.4, 2.2)
1.1 (0.5, 1.6)
1.0 .872 (0.3, 1.7)
2.4 (1.5, 3.3)
2.4 .973 (1.0, 3.7)
d-als
1.6 (0.8, 2.4)
1.0 .213 (0.4, 1.5)
3.4 (1.5, 5.2)
3.4 .861 (1.5, 5.4)
3.6 (2.6, 4.6)
1.7 .003a (1.0, 2.3)
5.6 (4.0, 7.2)
4.2 .030a (2.4, 6.1)
d-al
1.6 (0.7, 2.5)
1.5 .852 (0.8, 2.2)
4.2 4.3 (1.5, (1.8, 6.5) 7.1)
.859
2.1 (0.9, 3.3)
2.4 .715 (1.3, 3.5)
5.6 (3.5, 7.6)
5.6 .965 (3.0, 8.2)
d-ali
1.8 (0.9, 2.7)
1.8 .988 (0.8, 2.8)
3.9 (1.9, 5.9)
4.4 .358 (1.9, 7.0)
4.7 (2.8, 6.5)
2.6 .092 (1.5, 3.7)
6.7 (4.4, 9.1)
6.1 .438 (4.1, 8.2)
d-ch
3.5 (2.1, 5.0)
2.8 .219 (1.7, 3.9)
7.2 (5.2, 9.1)
6.6 .660 (3.9, 9.4)
3.5 (1.0, 5.9)
2.8 .493 (1.2, 4.5)
9.4 (7.1, 11.6)
8.1 (5.1, .044a 11.0)
d-cph
4.6 (2.4, 6.9)
4.5 .791 2.0 (1.2, (2.7, 7.1) 2.8)
1.8 .542 (0.6, 3.0)
4.0 (2.6, 5.4)
0.8 (0.5, .003a 1.1)
6.8 (4.6, 9.0)
5.3 .038a (3.0, 7.7)
ls
2.7 3.2 (1.5, .213 (1.1, 4.4) 5.0)
prn
1.6 (0.6, 2.5)
1.1 .375 (0.2, 2.1)
sn
1.2 (0.7, 1.7)
1.7 .195 (1.1, 2.4)
li
2.7 (1.0, 4.3)
2.0 .294 (0.7, 3.2)
P
Without Pros
With Pros
P
CL, confidence limit; Pros, prosthesis; d, defect side; ex, ectocanthion; en, entocanthion; als, alare superius; al, alare; ali, alare inferius; ch, cheilion; cph, christa philtri; ls, labrale superius; prn, pronasale; sn, subnasale; li, labrale inferius. a Significant difference in measurement points with vs without prosthesis.
position of the ch was not affected by the degree of lip support when the mandibular positions were kept constant. Analysis of the results of the present study indicates that the soft tissue close to the denture base of maxillary prostheses, such as cph and ali, shifts anteriorly, and that points in the middle distance from the denture base, such as ch and prn, shift laterally. On the normal side, only n-ch moved significantly with insertion of the maxillary prostheses. A previous study with the same analytical method as this one determined the asymmetry indices of the ex, al, and ch points on the right and left sides of normal individuals as well as the angles between the mid-sagittal
plane and the measurement lines that connect these 3 right- and left-side point pairs.34 That study reported asymmetry indices of 2.15% for ex, 3.95% for al, and 2.01% for ch. The angle of ex was 88.4 degrees, al was 87.3 degrees, and ch was 87.9 degrees. In the present study, the asymmetry indices among unilateral maxillary defect participants without a maxillary prosthesis was 2.07% for ex, 3.78% for al, and 6.52% for ch. With the prosthesis, the indices were 0.87% for ex, 4.36% for al, and 5.36% for ch. The angle without the prosthesis was 88.1 degrees for ex, 82.6 degrees for al, and 82.8 degrees for ch. With the prosthesis, the angle of ex was 87.9 degrees, al was 81.9 degrees and ch 83.8 degrees.
The Journal of Prosthetic Dentistry
Asymmetry indices of ex and al among the participants with unilateral maxillary defects were rarely different from those of the unaffected individuals in the previous study. However, the asymmetry index of ch among participants with unilateral maxillary defects was 3% to 5% higher than that of normal participants. No significant difference was found in the angle of the measurement line for ex to the midsagittal plane between the participants with maxillary defect and unaffected individuals, but the angles of the lines for al and ch were 4 to 6 degrees smaller among the participants with unilateral maxillary defects, regardless of whether or not the maxillary prosthesis was in place. In other words, these findings
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9
Orthogonal array of interactions between measurement points and prostheses on distances between ideal and defect side points (X / Y / Z)
Table V.
Measure. Point n-en n-als n-al n-ali n-cph n-ch
d-ex d-en d-als d-al d-ali d-cph d-ch prn sn ls li
n-ex
-/-/- -/-/* -/-/- -/-/- */-/- -/-/- -/-/- -/-/- -/-/* -/-/- -/-/- -/-/* -/-/-
-
-
-
-
n-en
-/-/* -/-/- -/-/- -/-/* -/-/- -/-/- -/-/- -/-/* -/-/- -/-/- -/-/* -/-/-
-
-
-
-
n-als
-/-/- -/-/- -/-/* -/-/* -/-/- -/-/* */-/- -/-/- -/-/- -/-/- -/-/-
-
-
-
-
n-al
-/-/- -/-/- -/-/- -/-/- -/-/- -/-/* -/-/- -/-/- -/-/* -/-/-
-
*
-
-
n-ali
-/-/- -/-/- -/-/- -/-/- -/-/- -/-/- -/-/- -/-/* -/-/-
-
-
-
-
-/-/- */-/- -/-/- -/-/* -/-/- -/-/- -/-/* -/-/-
-
-
-
-
n-cph n-ch
-/-/- -/-/- -/-/* -/-/- -/-/- -/-/* -/-/*
-
-
-
-
d-ex
-/-/- -/-/* -/-/- -/-/- -/-/* -/-/-
-
-
*
-
d-en
-/-/* -/-/- -/-/- -/-/* -/-/-
-
-
-
-
d-als
-/-/* -/-/- -/-/- -/-/-
-
-
-
-
d-al
-/-/- -/-/* -/-/-
-
-
-
-
d-ali
-/-/- -/-/-
-
-
-
-
-/-/-
-
-
-
-
-
-
-
-
-
-
-
-
-
d-cph d-ch prn sn ls
-
n, normal side; en, entocanthion; als, alare superius; ali, alare inferius; cph, christa philtri; ch, cheilion; d, defect side; ex, ectocanthion; al, alare; prn, pronasale; sn, subnasale; ls, labrale superius; li, labrale inferius; -, no significant interaction between measurement points and prostheses; *, significant interaction between measurement points and prostheses.
indicate that asymmetrical faces with a unilateral maxillary defect cannot be made completely symmetrical with the use of maxillary obturator prostheses of conventional design.
Table VI.
In an eye-tracking study, MeyerMarcotty et al26 found that an observer’s gaze is distracted to the nose and mouth area of a face with a unilateral cleft lip and palate. Moreover, individuals
with unilateral cleft lip and/or palate themselves focused greater attention on their anomalous features compared with participants without cleft lip and/or palate. Loss of teeth, loss of maxillary bone,
Asymmetry indices and angles of measurement lines to mid-sagittal reference plane
Asymmetry Index (%), mean (CLs)a Measurement Point or Line
Without Pros
Angle (degree), mean (CLs)b
With Pros
P
Without Pros
With Pros
P
ex
2.1 (0.5, 3.7)
0.9 (0.4, 1.4)
.185
88.1 (87.4, 88.9)
87.9 (86.9, 88.8)
.152
en
3.5 (0.7, 6.3)
4.4 (2.5, 6.3)
.561
87.4 (86.7, 88.2)
87.5 (86.7, 88.3)
.762
als
5.2 (2.6, 7.7)
6.1 (3.6, 8.5)
.649
83.0 (80.7, 85.3)
82.4 (78.7, 86.2)
.587
al
3.8 (1.6, 5.9)
4.4 (2.5, 6.2)
.684
82.6 (79.7, 85.4)
81.9 (78.6, 85.1)
.457
ali
5.2 (2.6, 7.8)
5.1 (2.5, 7.7)
.936
78.8 (74.9, 82.8)
79.5 (75.9, 83.1)
.314
ch
6.5 (4.1, 9.0)
5.4 (1.6, 9.1)
.677
82.8 (80.2, 85.5)
83.8 (81.7, 85.8)
.128
cph
37.3 (15.4, 59.3)
46.1 (27.2, 64.9)
.309
69.4 (61.3, 77.5)
77.4 (75.9, 83.1)
.012c
CL, confidence limit; Pros, prosthesis; ex, ectocanthion; en, entocanthion; als, alare superius; al, alare; ali, alare inferius; ch, cheilion; cph, christa philtri. a Asymmetry index: j D－N j 100/( D þ N ); D is the distance from defect side measurement point to mid-sagittal plane, N is the distance from normal side point to mid-sagittal plane. b Angle: acute angle between mid-sagittal plane and measurement line that connects measurement point of the normal side to corresponding point of defect side. c Significant difference in measurement points with vs without prosthesis.
Hanawa et al
10
Volume Orthogonal array of interactions between measurement points and prostheses on asymmetry indices and angles of measurement lines to mid-sagittal reference plane
Table VII.
Measurement Point or Line ex en als al
Asymmetry Index
Angle
4.
5.
en als al ali cph ch en als al ali cph ch -
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
ali cph
-
-
-
-
*
-
-
-
-
*
-
-
-
-
*
-
-
*
-
*
-
6.
7.
*
en, entocanthion; als, alare superius; al, alare; ali, alare inferius; cph, christa philtri; ch, cheilion; -, no significant interaction between measurement points and prostheses; *, significant interaction between measurement points and prostheses; ex, ectocanthion.
8.
of life. Changes in facial morphology that result from arbitrary alterations of the flange form of the maxillary prosthesis that do not affect oral function should be investigated. The flange form can affect facial morphology of individuals with maxillary defects, and its limitations will be determined by future research.
9.
loss and/or atrophy of orofacial muscles, loss and/or atrophy of adipose tissue, and cicatricial contracture, depending on the approach, can result from oncologic surgery for maxillary cancer. These postoperative morphologic abnormalities affect maxillofacial morphology, and, because individuals with unilateral maxillary defects also have anomalous features, the observer’s gaze may also focus on the asymmetrical region. Eugene et al35 determined the degree of facial asymmetry required to trigger a conscious perception of an observer by using a simulated model of facial paralysis. They reported that at least 3 mm of facial asymmetry at the oral commissure, brow, or both was required before participants detected the asymmetry. As shown in Table IV, the linear distances between ex, en, ls, prn, sn, and li on the defect side and their ideal points were approximately 3 mm or less, regardless of whether the prosthesis was in place. However, als, al, ali, ch, and cph were 4.23 to 9.39 mm (more than 3 mm) from their ideal points. To restore facial symmetry of patients with unilateral maxillary defects, new types of maxillary prostheses must be developed to decrease the linear distances to less than 3 mm between the defect side points and their ideal points around the nose and lips; new maxillary prostheses may need to be generated to improve patient quality
CONCLUSIONS Within the limitations of this study, the following conclusions were drawn. The maxillary obturator prosthesis significantly changed the facial morphology of the tip of the nose, the inferior nose, the nasal ala, the upper lip on the defect side, and the angles of the mouth on both sides horizontally but did not alter these areas vertically. The maxillary obturator prosthesis improves facial symmetry in the region of the nasal ala, the upper lip, and the angle of the mouth on the defect side of individuals with unilateral maxillary defects.
10.
11.
12.
13.
14.
15.
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