- Email: [email protected]
Placement of Teeth in a Complete Denture: A Cephalometric Study
P l a c e m e n t o f t e e t h in a c o m p l e t e d e n t u r e : a c e p h a lo m e tric s tu d y
Jack H. Rayson, DDS, New Orleans Arthur 0 . Rahn, DDS, Augusta, Ga Robert C. Wesley, DMD Davis Henderson, DDS Charles W. Ellinger, DDS, MSc Marvin Lutes, DMD Quentin Z. Frazier, DMD, Lexington, Ky
To determ ine the placement of a rtificia l teeth in relation to the underlying bone, a cephalometric analysis was made of 28 patients who had com plete dentures. Measurements obtained from the analysis were compared to an accepted ortho dontics standard fo r natural teeth position. Re sults indicate that the a rtific ia l anterior teeth have less labial angulation than the ideal natural teeth of these patients.
420
T he anterior teeth influence the contour o f the low er third o f the face as well as the tonicity of the muscles o f expression. T he currect or ideal position o f teeth for the best facial co ntour has long been o f concern to dentists.1-14 P rostho dontists attem pt to position and arrange artificial teeth so th at they appear natural, and create a pleasing profile. G uides for the accom plishm ent o f these objectives9*14-18 are the incisal papilla, the m ucolabial reflection, phonetics, and p re extraction photographs. A lthough these guides help in the arrangem ent o f artificial teeth, much of the denture appearance m ust be determ ined by the “ esthetic sense” o f the dentist. O rthodontists have studied several groups o f patients who have an ideal natural occlusion and a pleasing profile. F rom cephalom etric analyses o f these patients m ean values for several cranial points and tooth positions have been established. E stablished values can be used in the treatm ent o f patients who have an existing m alocclusion. A pparently, the closer the m alaligned teeth can be positioned to the m ean value established as “ ideal,” the better will be the esthetic result. C ephalom etric radiographs have often been used in dentistry since B roadbent19 established a rath er consistent m ethod for m aking these views. C ephalom etric studies have been done, on patients w ith com plete dentures, relative to bone changes under dentures,20 changes in facial height,20-22 changes in the soft tissue profile,22 and changes in the vertical dim ension of occlu sion and m andibular position.22-24 H ow ever, no reports have been m ade on studies th at com pare tooth placem ent on dentures to orthodontic concepts o f ideal placem ents. T he purpose o f this investigation was to de term ine, by m eans o f a cephalom etric analysis:
how closely the artificial anterior teeth arranged for a com plete denture, w ith use o f the previously m entioned phonetically and esthetically accept able guides, approxim ate the natural tooth m ean values described by som e orthodontists as ideal; and the relative accuracy o f the selected angu lation of the occlusal plan e com pared to the angulation o f the ideal n atu ral plane value.
M eth o d Tw enty-eight w hite patients, who ranged in age from 20 to 65 years w ere included in this study. These 28 patients, 15 m en and 13 wom en, w ere selected from a larger group o f 64 patients who w ere p articipating in another investigation that involved com plete d enture prosthodontics. They had been edentulous from 1 to 30 years w ith a m ean edentulous p erio d o f 12.5 years. All p a tients included in this study w ere edentulous at the tim e they w ere first exam ined. T h ere w ere no available pre-extraction records except p hoto graphs. Two o f the patients h ad n o t w orn com plete dentures previously. T h e rem aining p a tients previously h ad at least one set o f dentures. Selection o f patients for this investigation from the larger group was based on race and the type o f artificial teeth used in their dentures. D ifferent racial groups have facial characteristics and tooth characteristics th at are norm al for them . C o m p ar ison o f acceptable tooth arrangem ents of persons o f different races w ould not be valid. Patients fo r whom acrylic resin artificial teeth w ere r e quired w ere unacceptable for this study. A crylic resin teeth are radiolucent and, therefore, are n o t discernible on radiographic film. T he patients w ere assigned in a random m an n er to five dentists who w ere participating in the denture construction phase o f th e investi gation. T hree o f th e dentists constructed six den tures and tw o constructed five dentures. A ll d en tures w ere constructed in a sim ilar m anner. The anterior teeth w ere arranged by the d entist with use o f the previously m entioned guides. T he occlusal plane was determ ined by th e dentist; the m andibular canine was used to guide the an terio r height, and the retrom olar p a d to guide the posterior height. A ppearance of the trial den tures was approved by the dentist, the patient, and at least one other person. O n the day o f in itial placem ent o f the com pleted dentures, a lateral cephalom etric film was
m ade. T he X -ray source was a 90 kilovolt peak (kvp) m achine which was m ounted with a fixedsource film distance o f 60 inches. E ach p atient’s head was positioned in a cephalostat th at had been adjusted to superim pose the ear rods. T he film was located 14.5 cm from the p atien t’s m idsagittal plane. A fter the h ead was positioned, the p atien t was covered with a lead apron. A ll lateral exposures w ere m ade at 80 kvp with an exposure tim e o f 0.40 second. T he radiographic procedure gave some m agnification to the image on the film. By standardizing the source, the ta r get, and the film distance fo r all patients, how ever, any degree of m agnification projected was consistent for all. ■ Radiographic tracings: A tracing o f each film of the p atient’s left side was m ade on acetate paper. T he following p ertin en t cranial landm arks w ere traced: the cranial line (SN) draw n from the center of the sella turcica to nasion; the m andibu lar plane (gonion, gnathion); the palatal plane (ANS, PNS); the m axillary and m andibular cen tral incisors; and the occlusal plane. T he SN line was used only to aid in orienting the tracing. A line was draw n in the plane o f the long axis o f the m axillary incisor to intersect the p alatal plane. A line was draw n in a like m anner for the m andibular incisor to an intersection with the m andibular plane. T he occlusal plane was draw n betw een the two occluding first m olars and the two central incisors. I t was projected poster iorly to intersect the m andibular plane line (Fig 1). T he following angles w ere m easured: the angle form ed by the intersection of the long axis
Fig 1 ■ Angles are measured to determ ine a rtific ia l tooth placem ent relative to bony base.
Rayson-others: PLACEMENT OF TEETH IN DENTURE ■ 421
Table ■ Measured angles in degrees are shown fo r each patient. P a tie nt no.
1
3
4
5
6
An gle X to palatal plane
87
96.5
95
98.5
85
85.5
78.5
Angle T to m a n d ib u la r plane
81
Interi ncisal angle
1 70
15 9
16 5
Angle of occlusal plane to m a n d i b u la r plane
12
19
15
83.5
71
1 5 8 . 8 17 7
17
16
7
9
13
17
21
88
92
97
82.5
92.5
22
113
91
75
70
78
67
79.5
165
167
161
146
18 0
1 5 4 .5
7
18
24
30
20
20 . 5
line o f the m axillary incisor to the palatal plane; the angle form ed by the intersection o f the long axis line o f the m andibular incisor to the m an d ib u lar plane; the interincisal angle; the angle form ed by th e occlusal plane line and the m an dibular plane line. T he values obtained from m easuring these angles w ere com pared to the m ean values for an ideal natural occlusion* used by the F orsyth D ental C en ter-H arv ard School of D ental M edicine. M any different analyses are available that suggest standards for the natural tooth position, T w eed,2 Sassouni,4 and D ow ns,5 to m ention only a few. F o r this investigation, the F orsyth m a terial was selected as a com parison because it gives a m ean and standard deviation for th e p a r ticular areas of interest to this study, and the F orsyth m easurem ents were m ade on points that can be located with relative accuracy on edentu lous patients. T he Forsyth m aterial used in com parison for this study included: (A ') the angle form ed by the m axillary central incisor and th e palatal plane, m ean 110° with a standard deviation of 6 ° ; (B ') the angle form ed by the m andibular in cisor and the m andibular plane, m ean 9 1 ° with
26
31
33
35
39
42
43
45
92.5
95
97.5
94
95
102
94
98
94 1 3 5 .5
11
81
87
10 0
74
97
87
76
12 4
151
137
16 0
147
157
155
15
20
13 .5
16 . 5
16.5
29
13 .5
a standard deviation o f 8 .8 °; (C ') the interincisal angle form ed by the m axillary and m andibular central incisors, m ean 129° w ith a standard deviation o f 8 .8 °; and (D ') the can t o f the occlu sal plane, m ean 18° with a standard deviation o f 5°. A ll m easurem ents of the an terio r teeth indicate the angle of the tooth relative to its bony base and the angle of the upper incisor and lower incisor to each other. A n analysis of the p atien t’s cranial structures as they related to the m axilla and m an dible was not accom plished since points A and B are not constant in the edentulous p atien t25 and the pogonion m ay have changed its position b e cause o f loss o f the natural teeth. T he esthetic or “E ” line suggested by R icketts26 for the dentulous p atient could have been co n sidered in this analysis. It indicates the am ount of lip support provided by the teeth. A n E line is draw n from the tip o f the nose to the tip o f the soft tissues o f the chin. R icketts suggests that the upper lip should be 4 mm posterior to this line and the lower lip 2 mm posterior for an ideal profile. Such m easurem ents w ere n o t used b e cause of the age of the patients in this study. The nose continues to grow and change shape with age. T he average age o f the patients involved in this study would place them out o f the age group R icketts used in his analysis; this would invalidate the com parison of data.
R e s u lts a n d d is c u s s io n
DEGREE Fig 2 ■ D is trib u tio n graph shows relation of a rtific ia l m axil lary in ciso r to palatal plane.
422 ■ JADA, Vol. 81, August 1970
T he overall data from this investigation are p re sented in the Table. Figure 2 shows a distribution graph of the relationship of the m axillary central incisor to the palatal plane (angle A). F o r the p a tients in this investigation the m ean angle was 94.03° and the standard deviation was 7.31°. Only two o f the patients (7 .1 % ) were w ithin the range of ideal natural teeth. In no instances were
46
48
49
50
97.5
90
96
10 6
53
55
56
57
62
97.5
72
90
92
97
MEAN OF THIS INVESTIGATION 82.81° STANDARD DEVIATION 8 .0 2 ’ 91*
COMPARISON MEAN
8.8*
STANDARD DEVIATIO N
80.5
92
153
161 .5
18
8.5
86.5
91
80
80.5
1 5 3 .5 139
1 62
150 .5
17
19.5
13 . 5
22.5
85 1 6 4 .5
20
90
77
159
165
13
18
m axillary anterior teeth given a labial inclination greater than th at suggested for n atu ral teeth. T he relation o f the m andibular central incisor to the m andibular plane (angle B) is presented in Figure 3. In this m easurem ent it was found that 12 of the d enture patients (4 8 .8 % ) h ad an angle w ithin the F orsyth range. T he m ean angle for patients in this study was 8 2 .8 1 °. O f th e 16 p a tients outside the range, 1 p atien t had an incli natio n greater, and 15 patients h ad inclinations less than th a t suggested. Figure 4 shows the interincisal angle (angle C) in this study. T hree o f the patients (1 4 .2 % ) w ere w ithin the suggested range. Tw enty-five denture patients h ad an interincisal angle n o t in agreem ent w ith the natural tooth ideal. A ll o f these had readings in excess of the established norm . T he m ean value for this study was 156.35° and the stan d ard deviation was 12.14°. Figure 5 shows the angle form ed by the occlu sal plane and the m andibular plan e (angle D). T he angle form ed by the occlusal plan e and the m andibular plane in the d enture patients was m ore consistent with the F orsyth ideal. Tw entyone o f the patients (7 5 % ) h ad an occlusal plane angle in agreem ent w ith the ideal n atu ral teeth. T h e m ean value was 17.27° and the standard deviation was 5.14° for this investigation. F o r the other seven patients, the m easured angle was either above or below the standard. T hese findings indicate th at the 28 patients did not have as m uch angulation in their anterior teeth as exists in the ideal n atu ral teeth. Similar arrangem ents probably cause eith er a lack o f supp o rt o f the verm ilion b order o f the lip or an excessive support o f the m ucolabial fold area o f the lip. T o correct these discrepancies, an a rti ficial tooth should be m oved labially at the in cisal edge or lingually a t its cervical portion to approxim ate a natural position. N ot all patients have the developm ental bone
Fig 3 ■ D istrib u tio n graph shows relation of a rtific ia l m an d ib u la r in ciso r to m andibular plane.
120
130
MEAN FOR THIS INVESTIGATION STANDARD DEVIATION
156.35 12.14°
COMPARISON MEAN STANDARD DEVIATION
129* 8.8°
140
ISO
160
170
160
Fig 4 ■ D istrib u tio n graph shows relation of m axilla ry in cisor to m andibular incisor (in te rin cisa l angle).
I
MEAN FOR THIS INVESTIGATION 17.27° S TANDARD DEVIATION
5.14°
COMPARISON M EAN
18°
STANDARD DE V IA TIO N
5°
Fig 5 ■ D istrib u tion graph shows relation of a rtific ia l o cclu sal plane to m andibular plane.
Rayson—others: PLACEMENT OF TEETH IN DENTURE ■ 423
pattern th a t allows the positioning of the anterior teeth for an ideal profile. It is possible that a lack o f harm onious relationship between the natural teeth and th e ir bony support m ay have contributed to th e prem atu re loss of the p atien t’s natural teeth. T herefore, one w ould expect to have som e patients fo r whom the artificial teeth could not be positioned w ithin the standard established as ideal.
S u m m a r y a n d c o n c lu s io n A cephalom etric analysis was done on 28 patients w ith com plete dentures to determ ine the p lace m en t of th e artificial teeth in relation to the u n d er lying bone. T h e m easurem ents obtained from this analysis w ere com pared to an accepted o rth odon tics stan d ard for natural teeth position. T he re sults of this investigation indicate th a t the a rti ficial anterior teeth have less labial angulation than the ideal natural teeth for these 28 patients. T h e labial inclination o f the m andibular incisors approxim ated the labial inclination o f the natural teeth for 12 o f the patients. T he labial inclination th a t was given the m axillary incisors app roxi m ated th a t o f the natural teeth in only two p a tients. T h e established cant o f the occlusal plane was sim ilar for both the artificial and the ideal natu ral dentition. A fu rth er investigation is planned to construct dentures fo r these same patients and arrange the an terio r teeth w ithin the ranges o f angulation suggested by orthodontics standards. C om parative esthetic and phonetic results w ould then be avail able to guide the dentist in arranging artificial anterior teeth.
The information contained in this articlewas obtained from data previously collected from a research project (5-R01DH000-94-03) supported by the USPHS, division of grants. Doctor Rayson is associate professor and chairman of the department of prosthodontics, Louisiana State University School of Dentistry, 1190 Florida Ave, New Orleans, 70119. Doctor Wesley, Doctor Lutes, and Doctor Frazier are assis tant professors of prosthodontics; Doctor Henderson is associate professor and chairman of the department of prosthodontics; and Doctor Ellinger is an associate professor of prosthodontics and director of complete dentures, Univer sity of Kentucky College of Dentistry, Lexington, 40506. Doctor Rahn is associate professor and chairman of the department of prosthodontics, Medical College of Georgia School of Dentistry, Augusta, Ga. 424 ■ JADA, Vol. 81, August 1970
‘ Worksheet for clinical application of Bjork's analysis, department of orthodontics, Forsyth Dental Center, Boston.
1. Pound. E. Lost—fine arts in the fallacy of the ridges. J Prosth Dent 4:6 Jan 1954. 2. Tweed, C.H. Frankfort mandibular incisor angle (FMIA) in orthodontic diagnosis, treatment planning and prognosis. Angle Orthodont 24:121 July 1954. 3. Frush, J.P., and Fisher, R.D. Introduction to dentogenic restorations. J Prosth Dent 5:586 Sept 1955. 4. Sassouni, V. A roentgenographiccephalometricanalysis of chephalo-facial dental relationships. Amer J Orthodont 41:735 Oct 1955. 5. Downs, W.B. Analaysis of dentofacial profile. Angle Orthodont 26:192 Oct 1956. 6. DeVan, M.M. The appearance phase of denture con struction. Dent Clin N Amer March 1957, p 255. 7. Vig, R.G. The denture look. J Prosth Dent 11:9 JanFeb 1961. 8. Pound, E. Applying harmony in selecting and arranging teeth. Dent Clin N Amer March 1962, p 241. 9. Martone, A.L. Clinical application of concepts of func tional anatomy and speech science to complete denture prosthodontics, Part VIII. The final phases of denture con struction. J Prosth Dent 13:204 March-April 1963. 10. Krajicek, D.D. Achieving realism with complete den tures. J Prosth Dent 13:229 March-April 1964. 11. Martone, A.L. Effects of complete dentures on facial esthetics. J Prosth Dent 14:231 March-April 1964. 12. Martone, A.L. Complete denture esthetics and its relation to facial esthetics. Dent Clin N Amer March 1967, p 89. 13. Hartono, R. The occlusal plane in relation to facial types. J Prosth Dent 17:549 June 1967. 14. Marsden, A.C. Some practical measurements of tooth position in complete dentures. Aust Dent J 12:559 Dec 1967. 15. Maritato, F.R., and Douglas, J.R. Positive guide to an terior tooth placement. J Prosth Dent 14:848 Sept-Oct 1964. 16. Ellinger, C.W. Radiographic study of oral structures and their relation to anterior tooth position. J Prosth Dent 19: 36 Jan 1968. 17. Harper, R.N. Incisal papilla—basis of technic to pro duce positions of key teeth in prosthodontia. J Dent Res 27: 661 Dec 1948. 18. Ribner, M.E. The role of phonetics in denture con struction. Dent Digest 71:106 March 1965. 19. Broadbent, B.H. A new X-ray technique and its appli cation to orthodontics. Angle Orthodont 1:45 1931. 20. Tallgren, A. Reduction in face height of edentulous and partially edentulous subjects during long-term wear. A longitudinal roentgenographic cephalometric study. Odont Scand 24:195 Sept 1966. 21. Ismail, Y.H. and others. Cephalometric study of the changes occurring in the face height following prosthetic treatment. J Prosth Dent 19:321 April 1968. 22. Apfel, D.A. Radiographic cephalometric study of the facial profile in individuals with complete dental prostheses. Amer J Orthodont 45:711 Sept 1959. (Abstract). 23. Basler, F.L. Cephalometric analysis of the vertical dimension of occlusion. J Prosth Dent 11:831 Sept-Oct 1961 24. Swerdlow, H. Roentgencephalometric study of ve rti cal dimension changes in immediate denture patients. J Prosth Dent 14:635 July-Aug 1964. 25. Coccaro, P.J., and Lloyd, R.S. Behavior of points A and B in denture patients. Amer J Orthodont 51:183 March 1965. 26. Ricketts, R.M. Planning treatment on the basis of the facial pattern and an estimate of its growth. Angle Orthodont 27:14 Jan 1957.
Jack H. Rayson, DDS, New Orleans Arthur 0 . Rahn, DDS, Augusta, Ga Robert C. Wesley, DMD Davis Henderson, DDS Charles W. Ellinger, DDS, MSc Marvin Lutes, DMD Quentin Z. Frazier, DMD, Lexington, Ky
To determ ine the placement of a rtificia l teeth in relation to the underlying bone, a cephalometric analysis was made of 28 patients who had com plete dentures. Measurements obtained from the analysis were compared to an accepted ortho dontics standard fo r natural teeth position. Re sults indicate that the a rtific ia l anterior teeth have less labial angulation than the ideal natural teeth of these patients.
420
T he anterior teeth influence the contour o f the low er third o f the face as well as the tonicity of the muscles o f expression. T he currect or ideal position o f teeth for the best facial co ntour has long been o f concern to dentists.1-14 P rostho dontists attem pt to position and arrange artificial teeth so th at they appear natural, and create a pleasing profile. G uides for the accom plishm ent o f these objectives9*14-18 are the incisal papilla, the m ucolabial reflection, phonetics, and p re extraction photographs. A lthough these guides help in the arrangem ent o f artificial teeth, much of the denture appearance m ust be determ ined by the “ esthetic sense” o f the dentist. O rthodontists have studied several groups o f patients who have an ideal natural occlusion and a pleasing profile. F rom cephalom etric analyses o f these patients m ean values for several cranial points and tooth positions have been established. E stablished values can be used in the treatm ent o f patients who have an existing m alocclusion. A pparently, the closer the m alaligned teeth can be positioned to the m ean value established as “ ideal,” the better will be the esthetic result. C ephalom etric radiographs have often been used in dentistry since B roadbent19 established a rath er consistent m ethod for m aking these views. C ephalom etric studies have been done, on patients w ith com plete dentures, relative to bone changes under dentures,20 changes in facial height,20-22 changes in the soft tissue profile,22 and changes in the vertical dim ension of occlu sion and m andibular position.22-24 H ow ever, no reports have been m ade on studies th at com pare tooth placem ent on dentures to orthodontic concepts o f ideal placem ents. T he purpose o f this investigation was to de term ine, by m eans o f a cephalom etric analysis:
how closely the artificial anterior teeth arranged for a com plete denture, w ith use o f the previously m entioned phonetically and esthetically accept able guides, approxim ate the natural tooth m ean values described by som e orthodontists as ideal; and the relative accuracy o f the selected angu lation of the occlusal plan e com pared to the angulation o f the ideal n atu ral plane value.
M eth o d Tw enty-eight w hite patients, who ranged in age from 20 to 65 years w ere included in this study. These 28 patients, 15 m en and 13 wom en, w ere selected from a larger group o f 64 patients who w ere p articipating in another investigation that involved com plete d enture prosthodontics. They had been edentulous from 1 to 30 years w ith a m ean edentulous p erio d o f 12.5 years. All p a tients included in this study w ere edentulous at the tim e they w ere first exam ined. T h ere w ere no available pre-extraction records except p hoto graphs. Two o f the patients h ad n o t w orn com plete dentures previously. T h e rem aining p a tients previously h ad at least one set o f dentures. Selection o f patients for this investigation from the larger group was based on race and the type o f artificial teeth used in their dentures. D ifferent racial groups have facial characteristics and tooth characteristics th at are norm al for them . C o m p ar ison o f acceptable tooth arrangem ents of persons o f different races w ould not be valid. Patients fo r whom acrylic resin artificial teeth w ere r e quired w ere unacceptable for this study. A crylic resin teeth are radiolucent and, therefore, are n o t discernible on radiographic film. T he patients w ere assigned in a random m an n er to five dentists who w ere participating in the denture construction phase o f th e investi gation. T hree o f th e dentists constructed six den tures and tw o constructed five dentures. A ll d en tures w ere constructed in a sim ilar m anner. The anterior teeth w ere arranged by the d entist with use o f the previously m entioned guides. T he occlusal plane was determ ined by th e dentist; the m andibular canine was used to guide the an terio r height, and the retrom olar p a d to guide the posterior height. A ppearance of the trial den tures was approved by the dentist, the patient, and at least one other person. O n the day o f in itial placem ent o f the com pleted dentures, a lateral cephalom etric film was
m ade. T he X -ray source was a 90 kilovolt peak (kvp) m achine which was m ounted with a fixedsource film distance o f 60 inches. E ach p atient’s head was positioned in a cephalostat th at had been adjusted to superim pose the ear rods. T he film was located 14.5 cm from the p atien t’s m idsagittal plane. A fter the h ead was positioned, the p atien t was covered with a lead apron. A ll lateral exposures w ere m ade at 80 kvp with an exposure tim e o f 0.40 second. T he radiographic procedure gave some m agnification to the image on the film. By standardizing the source, the ta r get, and the film distance fo r all patients, how ever, any degree of m agnification projected was consistent for all. ■ Radiographic tracings: A tracing o f each film of the p atient’s left side was m ade on acetate paper. T he following p ertin en t cranial landm arks w ere traced: the cranial line (SN) draw n from the center of the sella turcica to nasion; the m andibu lar plane (gonion, gnathion); the palatal plane (ANS, PNS); the m axillary and m andibular cen tral incisors; and the occlusal plane. T he SN line was used only to aid in orienting the tracing. A line was draw n in the plane o f the long axis o f the m axillary incisor to intersect the p alatal plane. A line was draw n in a like m anner for the m andibular incisor to an intersection with the m andibular plane. T he occlusal plane was draw n betw een the two occluding first m olars and the two central incisors. I t was projected poster iorly to intersect the m andibular plane line (Fig 1). T he following angles w ere m easured: the angle form ed by the intersection of the long axis
Fig 1 ■ Angles are measured to determ ine a rtific ia l tooth placem ent relative to bony base.
Rayson-others: PLACEMENT OF TEETH IN DENTURE ■ 421
Table ■ Measured angles in degrees are shown fo r each patient. P a tie nt no.
1
3
4
5
6
An gle X to palatal plane
87
96.5
95
98.5
85
85.5
78.5
Angle T to m a n d ib u la r plane
81
Interi ncisal angle
1 70
15 9
16 5
Angle of occlusal plane to m a n d i b u la r plane
12
19
15
83.5
71
1 5 8 . 8 17 7
17
16
7
9
13
17
21
88
92
97
82.5
92.5
22
113
91
75
70
78
67
79.5
165
167
161
146
18 0
1 5 4 .5
7
18
24
30
20
20 . 5
line o f the m axillary incisor to the palatal plane; the angle form ed by the intersection o f the long axis line o f the m andibular incisor to the m an d ib u lar plane; the interincisal angle; the angle form ed by th e occlusal plane line and the m an dibular plane line. T he values obtained from m easuring these angles w ere com pared to the m ean values for an ideal natural occlusion* used by the F orsyth D ental C en ter-H arv ard School of D ental M edicine. M any different analyses are available that suggest standards for the natural tooth position, T w eed,2 Sassouni,4 and D ow ns,5 to m ention only a few. F o r this investigation, the F orsyth m a terial was selected as a com parison because it gives a m ean and standard deviation for th e p a r ticular areas of interest to this study, and the F orsyth m easurem ents were m ade on points that can be located with relative accuracy on edentu lous patients. T he Forsyth m aterial used in com parison for this study included: (A ') the angle form ed by the m axillary central incisor and th e palatal plane, m ean 110° with a standard deviation of 6 ° ; (B ') the angle form ed by the m andibular in cisor and the m andibular plane, m ean 9 1 ° with
26
31
33
35
39
42
43
45
92.5
95
97.5
94
95
102
94
98
94 1 3 5 .5
11
81
87
10 0
74
97
87
76
12 4
151
137
16 0
147
157
155
15
20
13 .5
16 . 5
16.5
29
13 .5
a standard deviation o f 8 .8 °; (C ') the interincisal angle form ed by the m axillary and m andibular central incisors, m ean 129° w ith a standard deviation o f 8 .8 °; and (D ') the can t o f the occlu sal plane, m ean 18° with a standard deviation o f 5°. A ll m easurem ents of the an terio r teeth indicate the angle of the tooth relative to its bony base and the angle of the upper incisor and lower incisor to each other. A n analysis of the p atien t’s cranial structures as they related to the m axilla and m an dible was not accom plished since points A and B are not constant in the edentulous p atien t25 and the pogonion m ay have changed its position b e cause o f loss o f the natural teeth. T he esthetic or “E ” line suggested by R icketts26 for the dentulous p atient could have been co n sidered in this analysis. It indicates the am ount of lip support provided by the teeth. A n E line is draw n from the tip o f the nose to the tip o f the soft tissues o f the chin. R icketts suggests that the upper lip should be 4 mm posterior to this line and the lower lip 2 mm posterior for an ideal profile. Such m easurem ents w ere n o t used b e cause of the age of the patients in this study. The nose continues to grow and change shape with age. T he average age o f the patients involved in this study would place them out o f the age group R icketts used in his analysis; this would invalidate the com parison of data.
R e s u lts a n d d is c u s s io n
DEGREE Fig 2 ■ D is trib u tio n graph shows relation of a rtific ia l m axil lary in ciso r to palatal plane.
422 ■ JADA, Vol. 81, August 1970
T he overall data from this investigation are p re sented in the Table. Figure 2 shows a distribution graph of the relationship of the m axillary central incisor to the palatal plane (angle A). F o r the p a tients in this investigation the m ean angle was 94.03° and the standard deviation was 7.31°. Only two o f the patients (7 .1 % ) were w ithin the range of ideal natural teeth. In no instances were
46
48
49
50
97.5
90
96
10 6
53
55
56
57
62
97.5
72
90
92
97
MEAN OF THIS INVESTIGATION 82.81° STANDARD DEVIATION 8 .0 2 ’ 91*
COMPARISON MEAN
8.8*
STANDARD DEVIATIO N
80.5
92
153
161 .5
18
8.5
86.5
91
80
80.5
1 5 3 .5 139
1 62
150 .5
17
19.5
13 . 5
22.5
85 1 6 4 .5
20
90
77
159
165
13
18
m axillary anterior teeth given a labial inclination greater than th at suggested for n atu ral teeth. T he relation o f the m andibular central incisor to the m andibular plane (angle B) is presented in Figure 3. In this m easurem ent it was found that 12 of the d enture patients (4 8 .8 % ) h ad an angle w ithin the F orsyth range. T he m ean angle for patients in this study was 8 2 .8 1 °. O f th e 16 p a tients outside the range, 1 p atien t had an incli natio n greater, and 15 patients h ad inclinations less than th a t suggested. Figure 4 shows the interincisal angle (angle C) in this study. T hree o f the patients (1 4 .2 % ) w ere w ithin the suggested range. Tw enty-five denture patients h ad an interincisal angle n o t in agreem ent w ith the natural tooth ideal. A ll o f these had readings in excess of the established norm . T he m ean value for this study was 156.35° and the stan d ard deviation was 12.14°. Figure 5 shows the angle form ed by the occlu sal plane and the m andibular plan e (angle D). T he angle form ed by the occlusal plan e and the m andibular plane in the d enture patients was m ore consistent with the F orsyth ideal. Tw entyone o f the patients (7 5 % ) h ad an occlusal plane angle in agreem ent w ith the ideal n atu ral teeth. T h e m ean value was 17.27° and the standard deviation was 5.14° for this investigation. F o r the other seven patients, the m easured angle was either above or below the standard. T hese findings indicate th at the 28 patients did not have as m uch angulation in their anterior teeth as exists in the ideal n atu ral teeth. Similar arrangem ents probably cause eith er a lack o f supp o rt o f the verm ilion b order o f the lip or an excessive support o f the m ucolabial fold area o f the lip. T o correct these discrepancies, an a rti ficial tooth should be m oved labially at the in cisal edge or lingually a t its cervical portion to approxim ate a natural position. N ot all patients have the developm ental bone
Fig 3 ■ D istrib u tio n graph shows relation of a rtific ia l m an d ib u la r in ciso r to m andibular plane.
120
130
MEAN FOR THIS INVESTIGATION STANDARD DEVIATION
156.35 12.14°
COMPARISON MEAN STANDARD DEVIATION
129* 8.8°
140
ISO
160
170
160
Fig 4 ■ D istrib u tio n graph shows relation of m axilla ry in cisor to m andibular incisor (in te rin cisa l angle).
I
MEAN FOR THIS INVESTIGATION 17.27° S TANDARD DEVIATION
5.14°
COMPARISON M EAN
18°
STANDARD DE V IA TIO N
5°
Fig 5 ■ D istrib u tion graph shows relation of a rtific ia l o cclu sal plane to m andibular plane.
Rayson—others: PLACEMENT OF TEETH IN DENTURE ■ 423
pattern th a t allows the positioning of the anterior teeth for an ideal profile. It is possible that a lack o f harm onious relationship between the natural teeth and th e ir bony support m ay have contributed to th e prem atu re loss of the p atien t’s natural teeth. T herefore, one w ould expect to have som e patients fo r whom the artificial teeth could not be positioned w ithin the standard established as ideal.
S u m m a r y a n d c o n c lu s io n A cephalom etric analysis was done on 28 patients w ith com plete dentures to determ ine the p lace m en t of th e artificial teeth in relation to the u n d er lying bone. T h e m easurem ents obtained from this analysis w ere com pared to an accepted o rth odon tics stan d ard for natural teeth position. T he re sults of this investigation indicate th a t the a rti ficial anterior teeth have less labial angulation than the ideal natural teeth for these 28 patients. T h e labial inclination o f the m andibular incisors approxim ated the labial inclination o f the natural teeth for 12 o f the patients. T he labial inclination th a t was given the m axillary incisors app roxi m ated th a t o f the natural teeth in only two p a tients. T h e established cant o f the occlusal plane was sim ilar for both the artificial and the ideal natu ral dentition. A fu rth er investigation is planned to construct dentures fo r these same patients and arrange the an terio r teeth w ithin the ranges o f angulation suggested by orthodontics standards. C om parative esthetic and phonetic results w ould then be avail able to guide the dentist in arranging artificial anterior teeth.
The information contained in this articlewas obtained from data previously collected from a research project (5-R01DH000-94-03) supported by the USPHS, division of grants. Doctor Rayson is associate professor and chairman of the department of prosthodontics, Louisiana State University School of Dentistry, 1190 Florida Ave, New Orleans, 70119. Doctor Wesley, Doctor Lutes, and Doctor Frazier are assis tant professors of prosthodontics; Doctor Henderson is associate professor and chairman of the department of prosthodontics; and Doctor Ellinger is an associate professor of prosthodontics and director of complete dentures, Univer sity of Kentucky College of Dentistry, Lexington, 40506. Doctor Rahn is associate professor and chairman of the department of prosthodontics, Medical College of Georgia School of Dentistry, Augusta, Ga. 424 ■ JADA, Vol. 81, August 1970
‘ Worksheet for clinical application of Bjork's analysis, department of orthodontics, Forsyth Dental Center, Boston.
1. Pound. E. Lost—fine arts in the fallacy of the ridges. J Prosth Dent 4:6 Jan 1954. 2. Tweed, C.H. Frankfort mandibular incisor angle (FMIA) in orthodontic diagnosis, treatment planning and prognosis. Angle Orthodont 24:121 July 1954. 3. Frush, J.P., and Fisher, R.D. Introduction to dentogenic restorations. J Prosth Dent 5:586 Sept 1955. 4. Sassouni, V. A roentgenographiccephalometricanalysis of chephalo-facial dental relationships. Amer J Orthodont 41:735 Oct 1955. 5. Downs, W.B. Analaysis of dentofacial profile. Angle Orthodont 26:192 Oct 1956. 6. DeVan, M.M. The appearance phase of denture con struction. Dent Clin N Amer March 1957, p 255. 7. Vig, R.G. The denture look. J Prosth Dent 11:9 JanFeb 1961. 8. Pound, E. Applying harmony in selecting and arranging teeth. Dent Clin N Amer March 1962, p 241. 9. Martone, A.L. Clinical application of concepts of func tional anatomy and speech science to complete denture prosthodontics, Part VIII. The final phases of denture con struction. J Prosth Dent 13:204 March-April 1963. 10. Krajicek, D.D. Achieving realism with complete den tures. J Prosth Dent 13:229 March-April 1964. 11. Martone, A.L. Effects of complete dentures on facial esthetics. J Prosth Dent 14:231 March-April 1964. 12. Martone, A.L. Complete denture esthetics and its relation to facial esthetics. Dent Clin N Amer March 1967, p 89. 13. Hartono, R. The occlusal plane in relation to facial types. J Prosth Dent 17:549 June 1967. 14. Marsden, A.C. Some practical measurements of tooth position in complete dentures. Aust Dent J 12:559 Dec 1967. 15. Maritato, F.R., and Douglas, J.R. Positive guide to an terior tooth placement. J Prosth Dent 14:848 Sept-Oct 1964. 16. Ellinger, C.W. Radiographic study of oral structures and their relation to anterior tooth position. J Prosth Dent 19: 36 Jan 1968. 17. Harper, R.N. Incisal papilla—basis of technic to pro duce positions of key teeth in prosthodontia. J Dent Res 27: 661 Dec 1948. 18. Ribner, M.E. The role of phonetics in denture con struction. Dent Digest 71:106 March 1965. 19. Broadbent, B.H. A new X-ray technique and its appli cation to orthodontics. Angle Orthodont 1:45 1931. 20. Tallgren, A. Reduction in face height of edentulous and partially edentulous subjects during long-term wear. A longitudinal roentgenographic cephalometric study. Odont Scand 24:195 Sept 1966. 21. Ismail, Y.H. and others. Cephalometric study of the changes occurring in the face height following prosthetic treatment. J Prosth Dent 19:321 April 1968. 22. Apfel, D.A. Radiographic cephalometric study of the facial profile in individuals with complete dental prostheses. Amer J Orthodont 45:711 Sept 1959. (Abstract). 23. Basler, F.L. Cephalometric analysis of the vertical dimension of occlusion. J Prosth Dent 11:831 Sept-Oct 1961 24. Swerdlow, H. Roentgencephalometric study of ve rti cal dimension changes in immediate denture patients. J Prosth Dent 14:635 July-Aug 1964. 25. Coccaro, P.J., and Lloyd, R.S. Behavior of points A and B in denture patients. Amer J Orthodont 51:183 March 1965. 26. Ricketts, R.M. Planning treatment on the basis of the facial pattern and an estimate of its growth. Angle Orthodont 27:14 Jan 1957.