Denture tooth central incisor Part II
selection: An analysis of the natural maxillary compared to the length and width of the face:
Arthur M. LaVere, DDS,* Keith R. Marcroft, DMD,b Roland C. Smith, DDS,* and Robert J. Sarka, DDS, MSC University
of the Pacific,
School
of Dentistry,
San Francisco,
Calif.
This is the second part of a project conducted by the Removable Prosthodontic Faculty to compare the length and width of the maxillary central incisor with the length and width of the face. In this article, gender of the students was the main consideration. Three hundred fifty men and 138 women students participated in the project. (J PROSTHET DENT 1992;67:810-2.)
F
or the past 4 years, 488 doctoral dental students and 12 departmental faculty participated in a project to determine the relationship of the length and width of the maxillary incisors and the length and width of the face. There were 350 men and 138 women students. Working in pairs, each student measured the length and width of the right maxillary central incisor on the other student’s cast,
and also the length and width of that student’s face using the Trubyte (Dentsply International, Inc., York, Pa.) tooth indicator. A faculty member verified all measurements. The readings were recorded on a prescription form that also indicated the subject’s gender. Part I of this report ineluded results of all subjects, whereas Part II separates the results according to gender. RESULTS
aProfessor, Removable Prosthodontics Department. bClinical Associate Professor, Removable Prosthodontics Department. CAssociate Professor, Removable Prosthodontics Department.
This project revealed that 112 of the 488 subjects had a face width larger than their cast width measurement. Eighty-four (75 %) were men and 28 (25% ) were women. Of the 11.3 students who had face widths the same size as the
10/l/35795
Table
I All
subjects
Men
Women
-
Face width versus cast width FW larger than CW FW smaller than CW FW the same as CW Total Face width within +0.5 mm of cast Face width within f 1 mm of cast width Face width within + 1.5 mm of cast width Face width within + 2.0 mm of cast width Face length versus cast length FL longer than CL, FL shorter than CIL FL the same CL Total Face length within +0.5 mm of cast length Face length within k 1 mm of cast length Face length within f 1.5 mm of cast length Face length within k2.0 mm of cast length Identical measurements Face length and width both the same as cast FW, Face width;
810
CW, cast width;
FL, face length;
%
90
N
%
N
112 263 -113 488 294 402 453 476
23.0 53.9 23.2
84 182 - 84 350 212 287 326 341
75.0 69.2 74.3
28 81 - 29 138 82 115 127 135
25.0 30.8 25.7
353 64 7
72.3 13.1 14.5
71.7 70.3 73.2
45.1 66.6 83.6 90.8
73.2 74.5 74.0 72.5
100 19 - 19 138 59 83 106 122
28.3 29.7 26.8
488 220 325 408 443
253 45 - 52 350 161 242 302 321
19
3.9
13
68.4
6
31.6
N
60.2 82.4 92.8 97.5
72.1 71.4 72.1 71.6
27.9 28.6 28.0 28.4
26.8 25.5 26.0 27.5
CL, cast length.
JUNE
1992
VOLUME
67
NUMBER
6
DENTURE
TOOTH
SELECTION:
PART
II
100 90 80 70 g 60 850 %40 30 20 10 0
Fig.
2. Percentage
cast widths, 84 (74.3% ) were men and 29 (25.7%) were women. Of the 263 students who had face widths smaller than their cast widths, 182 (69.2%) were men and 81 (30.8%) were women. Of the 64 students who had facial lengths smaller than cast length, 45 (70.3%) were men and 19 (29.7%) were women. Of the 71 students who had facial lengths the same as the cast length, 52 (73.2%) were men and 19 (26.8%) were women (Table I). Of the 353 students who had facial lengths longer than cast lengths, 253 (71.7 % ) were men and 100 (28.3%) were women. The percentage of men versus women when facial dimensions were compared to cast dimensions was nearly the same as that in the total number of subjects in virtually every category of measurement. Indeed, there was no instance in which it varied by a statistically significant amount when subjected to chi-square analysis (Figs. 1 and 2).
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
of women
Table
by category.
II.
Comparison
of face forms
All subjects
Square Tapering Ovoid Square tapering
(N = 488)
MelI
Women
N
%
N
%
N
%
52 17 190
10.7 3.5 38.9
229
46.9
46 14 105 182
88.5 82.4 55.3 79.5
6 3 85 47
11.5 17.6 44.7 20.5
CONCLUSION It is evident from these results that if the Trubyte tooth indicator is used to select denture teeth for patients in the 20 to 30 year age group, more than 50 % of the teeth selected will be narrower than the natural incisors and 72% of the
811
LAVEREETAL
teeth selected will be longer for both men and women. On the other hand, the majority of the teeth selected will be within 1 mm of both the length and width of the natural tooth dimensions. An interesting sidelight of this project resulted when face forms were determined by use of the tooth indicator (Table II).
Contributing authors Daniel M. Castagna, DDS, Stafford J. Duhn, DDS, Benjamin E. Dooley, DMD, Anthony R. Maniscalco, DDS, Susan J. Protzel, DDS, Dennis D. Shinbori, DDS, Craig S. Yarborough, DDS, Gerald W. Holloway, CDT, University of the Pacific, School of
Dentistry, Removable Prosthodontics Department.
Reprint requests to: ARTHUR M. LAVERE, DDS SCHOOL OF DENTISTRY UNIVERSITY OF THE PACIFIC 2155 WEBSTER ST. SAN FRANCISCO, CA 94115
Laboratory teeth Sheldon Winkler, Jason KwokC
wear DDS,a
investigation George
E. Monasky,
of resin posterior DDS,
MSP,b
denture
and
Temple University, Schoolof Dentistry, Philadelphia, Pa. This investigation compared the wear resistance of three “improved” resin posterior denture tooth formulations with two conventional products on a mechanical toothbrush abrasion machine. The ability of the teeth to resist this type of abrasion was evaluated by determination of the weight loss during 339 hours of brushing with firm nylon bristle toothbrushes. All brands exhibited negligible loss, with the conventional brands performing better than the “improved” formulations. (J PROSTHET DENT 1992;67:812-4.)
R
esin teeth were introduced in the early 1930s and are used today in the fabrication of a majority of removable prostheses. Among the advantages claimed for resin teeth, as opposed to porcelain teeth, are a more natural appearance, less breakage, a reduction of clicking, a better bond between the teeth and the resin base, and the ease of grinding, recontouring, and repo1ishing.l A major disadvantage of resin teeth is the rapid wear of posterior tooth surfaces. While the wear resistance of acrylic resin teeth has improved since their introduction to the profession, the possibility exists that the wear factor can unfavorably affect the occlusal vertical dimension and tooth relationships, causing stresseson the oral mucosa and underlying bone and adversely influencing esthetics.
Partially supported by Grant No. 07.535RU from the Ben Franklin Partnership Program of the Commonwealth of Pennsylvania. BProfeasor,Department of Prosthodontics. bProfesaor,Department of Prosthodontics. “Dental student, researchassistant. 10/l/36563
812
An investigation of the abrasion characteristics of anatomic acrylic resin denture teeth produced by three different manufacturers (Dentsply International, York, Pa., Myerson Tooth Corp., Cambridge, Mass., and Lactona Corp., Morris Plains, N.J.) found small but clinically insignificant differences among the brands tested. The investigators concluded that the selection of teeth should be based on personal preference and esthetic considerations rather than on assumed differences in wear rates.2 In an attempt to “provide all the ease of adjustment and patient adaptability usually associated with plastic” while providing increased wear resistance,3 a major artificial tooth manufacturer developed a new tooth material (Trubyte Bioform IPN, Dentsply International, York, Pa.). These teeth were said to minimize the disadvantages of acrylic resin teeth and enhance certain of their desirable qualities.* The new tooth material was composed of an unfilled, highly cross-linked, interpenetrating polymer network. Interpenetrating polymer networks are structures formed when a polymer is cross-linked into a three-dimensional network occupied by a second cross-linked polymer. The
JUNE1992
VOLUME67
NUMBER6
selection: An analysis of the natural maxillary compared to the length and width of the face:
Arthur M. LaVere, DDS,* Keith R. Marcroft, DMD,b Roland C. Smith, DDS,* and Robert J. Sarka, DDS, MSC University
of the Pacific,
School
of Dentistry,
San Francisco,
Calif.
This is the second part of a project conducted by the Removable Prosthodontic Faculty to compare the length and width of the maxillary central incisor with the length and width of the face. In this article, gender of the students was the main consideration. Three hundred fifty men and 138 women students participated in the project. (J PROSTHET DENT 1992;67:810-2.)
F
or the past 4 years, 488 doctoral dental students and 12 departmental faculty participated in a project to determine the relationship of the length and width of the maxillary incisors and the length and width of the face. There were 350 men and 138 women students. Working in pairs, each student measured the length and width of the right maxillary central incisor on the other student’s cast,
and also the length and width of that student’s face using the Trubyte (Dentsply International, Inc., York, Pa.) tooth indicator. A faculty member verified all measurements. The readings were recorded on a prescription form that also indicated the subject’s gender. Part I of this report ineluded results of all subjects, whereas Part II separates the results according to gender. RESULTS
aProfessor, Removable Prosthodontics Department. bClinical Associate Professor, Removable Prosthodontics Department. CAssociate Professor, Removable Prosthodontics Department.
This project revealed that 112 of the 488 subjects had a face width larger than their cast width measurement. Eighty-four (75 %) were men and 28 (25% ) were women. Of the 11.3 students who had face widths the same size as the
10/l/35795
Table
I All
subjects
Men
Women
-
Face width versus cast width FW larger than CW FW smaller than CW FW the same as CW Total Face width within +0.5 mm of cast Face width within f 1 mm of cast width Face width within + 1.5 mm of cast width Face width within + 2.0 mm of cast width Face length versus cast length FL longer than CL, FL shorter than CIL FL the same CL Total Face length within +0.5 mm of cast length Face length within k 1 mm of cast length Face length within f 1.5 mm of cast length Face length within k2.0 mm of cast length Identical measurements Face length and width both the same as cast FW, Face width;
810
CW, cast width;
FL, face length;
%
90
N
%
N
112 263 -113 488 294 402 453 476
23.0 53.9 23.2
84 182 - 84 350 212 287 326 341
75.0 69.2 74.3
28 81 - 29 138 82 115 127 135
25.0 30.8 25.7
353 64 7
72.3 13.1 14.5
71.7 70.3 73.2
45.1 66.6 83.6 90.8
73.2 74.5 74.0 72.5
100 19 - 19 138 59 83 106 122
28.3 29.7 26.8
488 220 325 408 443
253 45 - 52 350 161 242 302 321
19
3.9
13
68.4
6
31.6
N
60.2 82.4 92.8 97.5
72.1 71.4 72.1 71.6
27.9 28.6 28.0 28.4
26.8 25.5 26.0 27.5
CL, cast length.
JUNE
1992
VOLUME
67
NUMBER
6
DENTURE
TOOTH
SELECTION:
PART
II
100 90 80 70 g 60 850 %40 30 20 10 0
Fig.
2. Percentage
cast widths, 84 (74.3% ) were men and 29 (25.7%) were women. Of the 263 students who had face widths smaller than their cast widths, 182 (69.2%) were men and 81 (30.8%) were women. Of the 64 students who had facial lengths smaller than cast length, 45 (70.3%) were men and 19 (29.7%) were women. Of the 71 students who had facial lengths the same as the cast length, 52 (73.2%) were men and 19 (26.8%) were women (Table I). Of the 353 students who had facial lengths longer than cast lengths, 253 (71.7 % ) were men and 100 (28.3%) were women. The percentage of men versus women when facial dimensions were compared to cast dimensions was nearly the same as that in the total number of subjects in virtually every category of measurement. Indeed, there was no instance in which it varied by a statistically significant amount when subjected to chi-square analysis (Figs. 1 and 2).
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
of women
Table
by category.
II.
Comparison
of face forms
All subjects
Square Tapering Ovoid Square tapering
(N = 488)
MelI
Women
N
%
N
%
N
%
52 17 190
10.7 3.5 38.9
229
46.9
46 14 105 182
88.5 82.4 55.3 79.5
6 3 85 47
11.5 17.6 44.7 20.5
CONCLUSION It is evident from these results that if the Trubyte tooth indicator is used to select denture teeth for patients in the 20 to 30 year age group, more than 50 % of the teeth selected will be narrower than the natural incisors and 72% of the
811
LAVEREETAL
teeth selected will be longer for both men and women. On the other hand, the majority of the teeth selected will be within 1 mm of both the length and width of the natural tooth dimensions. An interesting sidelight of this project resulted when face forms were determined by use of the tooth indicator (Table II).
Contributing authors Daniel M. Castagna, DDS, Stafford J. Duhn, DDS, Benjamin E. Dooley, DMD, Anthony R. Maniscalco, DDS, Susan J. Protzel, DDS, Dennis D. Shinbori, DDS, Craig S. Yarborough, DDS, Gerald W. Holloway, CDT, University of the Pacific, School of
Dentistry, Removable Prosthodontics Department.
Reprint requests to: ARTHUR M. LAVERE, DDS SCHOOL OF DENTISTRY UNIVERSITY OF THE PACIFIC 2155 WEBSTER ST. SAN FRANCISCO, CA 94115
Laboratory teeth Sheldon Winkler, Jason KwokC
wear DDS,a
investigation George
E. Monasky,
of resin posterior DDS,
MSP,b
denture
and
Temple University, Schoolof Dentistry, Philadelphia, Pa. This investigation compared the wear resistance of three “improved” resin posterior denture tooth formulations with two conventional products on a mechanical toothbrush abrasion machine. The ability of the teeth to resist this type of abrasion was evaluated by determination of the weight loss during 339 hours of brushing with firm nylon bristle toothbrushes. All brands exhibited negligible loss, with the conventional brands performing better than the “improved” formulations. (J PROSTHET DENT 1992;67:812-4.)
R
esin teeth were introduced in the early 1930s and are used today in the fabrication of a majority of removable prostheses. Among the advantages claimed for resin teeth, as opposed to porcelain teeth, are a more natural appearance, less breakage, a reduction of clicking, a better bond between the teeth and the resin base, and the ease of grinding, recontouring, and repo1ishing.l A major disadvantage of resin teeth is the rapid wear of posterior tooth surfaces. While the wear resistance of acrylic resin teeth has improved since their introduction to the profession, the possibility exists that the wear factor can unfavorably affect the occlusal vertical dimension and tooth relationships, causing stresseson the oral mucosa and underlying bone and adversely influencing esthetics.
Partially supported by Grant No. 07.535RU from the Ben Franklin Partnership Program of the Commonwealth of Pennsylvania. BProfeasor,Department of Prosthodontics. bProfesaor,Department of Prosthodontics. “Dental student, researchassistant. 10/l/36563
812
An investigation of the abrasion characteristics of anatomic acrylic resin denture teeth produced by three different manufacturers (Dentsply International, York, Pa., Myerson Tooth Corp., Cambridge, Mass., and Lactona Corp., Morris Plains, N.J.) found small but clinically insignificant differences among the brands tested. The investigators concluded that the selection of teeth should be based on personal preference and esthetic considerations rather than on assumed differences in wear rates.2 In an attempt to “provide all the ease of adjustment and patient adaptability usually associated with plastic” while providing increased wear resistance,3 a major artificial tooth manufacturer developed a new tooth material (Trubyte Bioform IPN, Dentsply International, York, Pa.). These teeth were said to minimize the disadvantages of acrylic resin teeth and enhance certain of their desirable qualities.* The new tooth material was composed of an unfilled, highly cross-linked, interpenetrating polymer network. Interpenetrating polymer networks are structures formed when a polymer is cross-linked into a three-dimensional network occupied by a second cross-linked polymer. The
JUNE1992
VOLUME67
NUMBER6
