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Perceptions of dentofacial morphology by laypersons, general dentists, and orthodontists
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0
ARTICLES
Perceptions of dentofacial morphology by laypersons, general dentists, and orthodontists Birte Prahl-A ndersen, DDS, PhD H erm an Boersma, DDS, PhD Frans P. G. M. van der Linden, DDS, PhD Alton W. Moore, DDS, MS,
Eleven drawings of facial profiles and 11 photographs of dentitions were evaluated by parents, general practitioners of dentistry, and orthodontists for normality and for the necessity for orthodontic treatment. A three-point scale was used.
T
Jinp draw ings of facial profiles and color photographs of dentitions were subjectively rated by three in dependent groups to determ ine per ception of norm ality in dentofacial morphology. One group included parents of children participating in the Nymegen Growth Study, one was com posed of general practi tioners of dentistry, and the third was made up of orthodontists. The purpose of the study was to obtain inform ation about the differences betw een the three groups in their judgm ent of typical m orphological features and their assessm ent of the need for orthodontic treatm ent.
Materials and methods W ithin the framework of the Nyme gen Growth Study ,1 1,150 fathers and m others were requested to rate
independently 11 line draw ings of facial profiles and 11 intraoral color photographs (Fig 1 , 2). The same pictures were subm itted for sim ilar rating to 83 orthodontists practicing in The N etherlands and to a ran dom ly selected group of 170 general practitioners of dentistry. Responses were received from 54 of the or thodontists and from 72 of the den tists. A predeterm ined three-point scale was used to evaluate the pic tures. The parents could choose be tw een normal, as it should be (1 ); slightly deviating, but not disturb ing (2 ); and abnormal, requiring treatm ent (3). The dentists and orthodontists were asked to indicate w hich de scription they considered m ost ap propriate to the pictures: this profile or dentition is norm al (1 ); this pro
file or dentition is deviating from norm al, but does not require or thodontic treatm ent (2 ); or this pro file or dentition is deviating from normal and does require orthodon tic treatm ent (3). The draw ings were presented on separate sheets m easuring 1 0 x 10 cm. The color photographs were presented separately and were 6X9 cm. The symbols seen on the pic tures were not on the originals.
Findings The Table presents the calculated means and standard deviations for the values of the responses to the 22 pictures. The ratings of the den tists and orthodontists are com bined because prelim inary evalua tion show ed that there w ere no sig nificant differences (with two ex ceptions) in the responses of the two groups. The m eans were calculated by to taling the individual responses for each evaluation according to the num erical rating system (1, 2, or 3), m ultiplying by 100 , and dividing by the num ber of responses. Thus, the m ean values range between 100 and 300. The standard deviation for each mean value was com puted in JADA, V ol. 98, February 1979 ■ 209
A R T IC L E S
the usual way. The symbols or “ + ” and “ (—)” or “ (+ )” are used to designate general conform ity in the group in th e evaluation. T he sym bols and w ere applied to m ean values betw een 250 and 300 and indicate that the m ajority rated the condition in the picture as ab norm al requiring treatm ent; m ean values of lCjO to 150, “ + ” or “ (+ )”, indicate they w ere judged as norm al by the majority. The profiles and dentitions rated as norm al by the m ajority of the parents are indicated by th e symbol “ + ” in the Table and in the Figures. Those rated as abnorm al, requiring treatm ent, are indicated by a m inus symbol, “ — The same procedure w as used for the com bined evaluations of the dentists and orthodontists; the same plus and m inus symbols w ere used, bu t they are enclosed in par entheses. The boxes on th e left in the illustrations indicate the par en ts’ responses, and the boxes on the right indicate the responses of the professionals. A significant difference betw een the judgm ent of the tw o groups (parents and professionals) is in d i cated by an asterisk placed beneath the highest value on the reproduc tions of the test illustrations and in the significance colum n in the Ta ble. The pictures that did not have adequate conformity in th e evalua tion, that is, m ean values betw een 151 and 249, do not have a symbol. In general, the dentists and or thodontists rated m ore of the test exam ples as abnormal th a n did the parents. An exception is picture 22 of a dentition that represents the “ugly duckling” stage of dental de velopm ent. For this exam ple (pic ture 22 ), there was also a significant difference registered betw een den tists and orthodontists. The latter more often scored picture 22 as norm al. The reverse w as true for profile picture 10 , in w hich more dentists found it acceptable than did orthodontists. For evaluations of bqth pictures 22 and 10 , the par ents were fairly uniform in their judgm ent. A greater consistency of rating was found for the profes210 ■ JADA, V ol. 98, February 1979
í V
y V
y
í
f( 7 + .r *
F ig 1 ■ L ine d ra w in g s o f fa c ia l p ro file s u s e d in e v a lu a tio n o f d e n to fa c ia l m o rp h o lo g y ; + m e a n s r a te d b y m a jo rity o f p a re n ts a s n o rm a l; - m e a n s r a te d b y m a jo rity o f p a r e n ts a s a b n o rm a l, re q u irin g tre a tm e n t; (+ ) m e a n s r a te d b y m a jo rity o f d e n tis ts a n d o rth o d o n tis ts a s n o rm a l; ( - ) m e a n s r a te d b y m a jo rity o f d e n tis ts a n d o rth o d o n tists a s a b n o rm a l, re q u irin g tre a tm e n t;* in d ic a te s s ig n ific a n t d if fe re n c e b e tw e e n p a re n ts ' a n d p ro fe s sio n a ls ’ e v a lu a tio n s , a n d is p la c e d u n d e r h ig h e s t value.
sional group. They were consistent in rating nine of the 11 facial profile \draw ings and nine of the 11 color photographs of the dentition. The averages and standard deviations in the Table allow com parison of the
rating given by the different groups. The data show interesting differ ences in the ratings of the different pictures as w ell as in the variation found in the judgm ent of the par ents and professionals.
ARTICLES
Discussion Results of the study indicate that a significant difference exists in the subjective evaluation of morphological characteristics in the dentofacial region between parents, dentists, and orthodontists. The observed differences are probably related to the differences among the three groups in knowledge of and experience in the subject. 2 Parents considered more pictures normal and acceptable than did the professional groups .3· 6 The differences between the dentists and orthodontists were small. It is assumed that the orthodontists considered the "ugly duckling" aspect of picture 22 as a normal developmental stage of the dentition. The higher rating of abnormality by orthodontists for picture 10 is probably related to the number of . orthodontists associating the profile with a Class II, Division 2, deep bite malocclusion similar to picture 15. Visual appearance was used as the only discriminating component in the determination of abnormality and the need for orthodontic treatment. Undoubtedly, the majority of the evaluators were influenced, consciously or subconsciously, by psychological, social, and other factors that they associated with the pictures.7- 9 The degree of handicapping accompanying dentofacial malformations is a combination of many factors and is related strongly to the person's psychosocial adjustment as well as to actual impairment of function or oral health. 1 <>- 12 Further, other considerations more readily assessable by dentists and orthodontists are essential in deciding whether treatment is indicated or desirable . These considerations include the state of oral hygiene, predisposition to caries, condition of the periodontium, the attitude of the patient and his motivation, and the actual need for orthodontic treatment. 13- 15 To determine the need for orthodontic treatment of a population and to distribute adequately the available manpower for the co"rrec-
Fig 2 • Dentitions used in evaluation. Symbols same as in Figure 1.
Table • Means and standard deviations for the values of responses by parents and by general dentists and orthodontists to drawings of facial profiles and photographs of dentitions.
No.
Mean
c·
SD
Dentists and orthodontists Mean SD Facial profile drawings
1 2 3 4 5 6 7 8 9 10
247 188 165 225 130 104 238 225 260 105 150
0 0 0 0
59 68 71 64 53 23 60 65 58 25 57
298 284 257 300 183 105 294 283 294 146 213
Parents
11
+ +
0 0
+ +
c
(-) (-) (-) (-) 0
(+)
(-! ~= (+
0
Differences between parents and professionals Significance' P value
13 37
X X
54
X X X
0 56 21 26 37 25 57 59
X X X X X
.0000 .0000 .0000 .0000 .0000 .7291 .0000 .0000 .0000 .0000 .0000
Color photographs of dentitions
12 13 14 15 16 17 18 19 20 21 22
276 206 228 292 230 142 290 267 183 224 297
0 0 0
+
0 0
50 73 72 29 66 65
32 51 73 67 18
288 296 237 299 263 135 292 273 290 244 262
(-) (-) 0
(- ) (+) (+)
(-) (-) (-) 0
(-)
33 20 53 9 48 53 27 48 32 54 58
X X X X
X X X
•c = Conformity in evaluation by majority of evaluators. = Significance of differences (P S .01).
t
tion of malocclusions, it must be realized that the image the layman has of a normal and abnormal dentofacial region differs significantly
from that of the professional who refers and treats malocclusions. Results of the study indicate that this is true at least in The Netherlands.
Prahl-Andersen-others : PERCEPTIONS OF DENTOFACIAL MORPHOLOGY • 211
.0092 .0000 .2005 .0061 .0000 .2343 .4930 .2055 .0000 .0015 .0000
A R T IC L E S
Summary Line draw ings of facial profiles and color photographs of dentitions w ere evaluated subjectively by 1,150 parents, 72 general practi tioners of dentistry, and 54 or thodontists w ith regard to the norm ality and abnorm ality in den tofacial m orphology and the need for orthodontic treatm ent. A significant difference was found b e tw e e n 'th e evaluations of the parents and the professional groups in ten of the 11 facial pro files and in seven of the 11 photo graphs of dentitions. In general, the parents considered more of the exam ples acceptable and not requiring orthodontic treatm ent than did the professional groups. The dentists and orthodon tists deviated significantly in their ratings only in their judgm ent of the “ugly d uckling” exam ple (picture 2 2 , h igher abnorm al rating by the dentists) and the profile example 10 (higher abnorm al rating by or thodontists). A num ber of orthodon tists may have associated the condi tion in picture 10 w ith a Class II,
212 m JADA, V ol. 98, February 1979
Division 2 m alocclusion and, as such, scored it abnormal.
T h is in v e stig atio n w as su p p o rte d in p a rt b y a g ra n t to th e N y m e g en G row th S tu d y from “ T he P rev e n tio n F u n d ,” th e H ague, T h e N e th er lan d s.
Drs. P ra h l-A n d erse n an d B oersm a are af filia te d w ith a n d Prof. v a n d e r L in d e n is h e ad o f th e d e p a rtm e n t of o rth o d o n tic s, U n iv ersity o f N y m eg en, T h e N e th erla n d s. Dr. M oore w as a F o g arty S e n io r In te rn a tio n a l F ello w a n d is p ro fesso r o f o rth o d o n tic s, U n iv e rsity o f W ash in g to n . S eattle. A d d re ss re q u e sts for re p rin ts to Dr. P rah l-A n d erse n . D epartm ent of O rth o d o n tic s, S ch o o l of D e ntistry, U n iv e rsity of N y m eg en . P h ilip s v a n L eydenlaan 25, N y m egen, T h e N e th erla n d s.
1. P rah l-A n d erse n , B., a n d K ow alski, C.J. A m ix ed lo n g itu d in a l, in te rd is c ip lin a ry stu d y of th e g ro w th a n d d e v e lo p m e n t o f D utch c h il dren . G ro w th 37:281-295, 1973. 2. S eco rd, P.F., a n d B ackm an, C.W. M aloc c lu sio n a n d p sy ch o lo g ica l factors. JADA 59:931-938, 1959. 3. In g erv all, B., a n d H edegard, B. A w are n e ss o f m a lo c c lu s io n a n d d e sire of o rth o d o n tic tre a tm e n t in 18-year-old S w e d ish m en. A cta O d o n to l S c a n d 32:93-101, 1974. 4. In g erv all, B. P rev a le n c e of d e ntal a n d oc c lu sa l a n o m a lies in S w e d ish c o n sc rip ts. A cta
O d o n to l S c a n d 32:83-92, 1974. 5. L in d eg a rd , B., a n d o thers. N eed a n d d e m a n d for o rth o d o n tic tre a tm e n t. T a n d la e g e b la d et 75(12}:1198-1210, 1971.
6. Shaw, W.C.; Lewis, H.G.; and Robertson, N.R. P e rc e p tio n o f m a lo c clu sio n . Br D ent J 138(6):211-216, 1975. 7. B eier, E.G., a n d others. R esponse to th e h u m a n face as a s tan d a rd stim u lu s: re e x am in atio n . J C onsult Psych 21(2):165-170, 1957. 8. F isk, R.O. P h y sio lo g ical an d so cio p sy c h o lo g ic al sig n ific a n ce o f m alo c clu sio n . J C an D ent A ssoc 29(l):635-643, 1963. 9. M acgregor, F.C. Social an d p sy ch o lo g ica l im p lic a tio n s o f d e ntofacial d isfig u re m e n t. A ngle O rth o d 40{3):231-233, 1970. 10. C lifford, E. P sychological a sp e c ts of o rofacial an o m alies: S peculations in s e a rc h of data. A SH A R eport no. 8, 1973. 11. C ohen, L.K. Social psych o lo g ical factors a sso c iated w ith m alo cclu sio n . Int D ent J 20:643-653, 1970. 12. Cox, N .H ., a n d V an d e r L in d en , F.P. Fa cial h a rm o n y . A m J O rthod 60:175-183, 1971. 13. K ow alski, C.J., a n d Prahl-A ndeT sen, B. S e le c tio n o f d e n to fa c ial m e a su re m e n ts for an o rth o d o n tic tre a tm e n t p rio rity in d e x . A ngle O rth o d 4 6 (l):94-97. 1976. 14. P rah l-A n d erse n , B., a n d B oersm a, H. De b e h o efte a an o rth o d o n tisc h e b e h a n d e lin g e n bij e en N ijm eegse p o p u la tie v a n 10, 5 jaar o u d e k in d e re n . N ed T ijd sc h r T a n d h e e lk 80:308-311, 1973. 15. S trieker, G. P sy ch o lo g ical issu e s p e r ta in in g to m a lo c clu sio n . A m J O rth o d 58(3):276-283, 1970.
0
ARTICLES
Perceptions of dentofacial morphology by laypersons, general dentists, and orthodontists Birte Prahl-A ndersen, DDS, PhD H erm an Boersma, DDS, PhD Frans P. G. M. van der Linden, DDS, PhD Alton W. Moore, DDS, MS,
Eleven drawings of facial profiles and 11 photographs of dentitions were evaluated by parents, general practitioners of dentistry, and orthodontists for normality and for the necessity for orthodontic treatment. A three-point scale was used.
T
Jinp draw ings of facial profiles and color photographs of dentitions were subjectively rated by three in dependent groups to determ ine per ception of norm ality in dentofacial morphology. One group included parents of children participating in the Nymegen Growth Study, one was com posed of general practi tioners of dentistry, and the third was made up of orthodontists. The purpose of the study was to obtain inform ation about the differences betw een the three groups in their judgm ent of typical m orphological features and their assessm ent of the need for orthodontic treatm ent.
Materials and methods W ithin the framework of the Nyme gen Growth Study ,1 1,150 fathers and m others were requested to rate
independently 11 line draw ings of facial profiles and 11 intraoral color photographs (Fig 1 , 2). The same pictures were subm itted for sim ilar rating to 83 orthodontists practicing in The N etherlands and to a ran dom ly selected group of 170 general practitioners of dentistry. Responses were received from 54 of the or thodontists and from 72 of the den tists. A predeterm ined three-point scale was used to evaluate the pic tures. The parents could choose be tw een normal, as it should be (1 ); slightly deviating, but not disturb ing (2 ); and abnormal, requiring treatm ent (3). The dentists and orthodontists were asked to indicate w hich de scription they considered m ost ap propriate to the pictures: this profile or dentition is norm al (1 ); this pro
file or dentition is deviating from norm al, but does not require or thodontic treatm ent (2 ); or this pro file or dentition is deviating from normal and does require orthodon tic treatm ent (3). The draw ings were presented on separate sheets m easuring 1 0 x 10 cm. The color photographs were presented separately and were 6X9 cm. The symbols seen on the pic tures were not on the originals.
Findings The Table presents the calculated means and standard deviations for the values of the responses to the 22 pictures. The ratings of the den tists and orthodontists are com bined because prelim inary evalua tion show ed that there w ere no sig nificant differences (with two ex ceptions) in the responses of the two groups. The m eans were calculated by to taling the individual responses for each evaluation according to the num erical rating system (1, 2, or 3), m ultiplying by 100 , and dividing by the num ber of responses. Thus, the m ean values range between 100 and 300. The standard deviation for each mean value was com puted in JADA, V ol. 98, February 1979 ■ 209
A R T IC L E S
the usual way. The symbols or “ + ” and “ (—)” or “ (+ )” are used to designate general conform ity in the group in th e evaluation. T he sym bols and w ere applied to m ean values betw een 250 and 300 and indicate that the m ajority rated the condition in the picture as ab norm al requiring treatm ent; m ean values of lCjO to 150, “ + ” or “ (+ )”, indicate they w ere judged as norm al by the majority. The profiles and dentitions rated as norm al by the m ajority of the parents are indicated by th e symbol “ + ” in the Table and in the Figures. Those rated as abnorm al, requiring treatm ent, are indicated by a m inus symbol, “ — The same procedure w as used for the com bined evaluations of the dentists and orthodontists; the same plus and m inus symbols w ere used, bu t they are enclosed in par entheses. The boxes on th e left in the illustrations indicate the par en ts’ responses, and the boxes on the right indicate the responses of the professionals. A significant difference betw een the judgm ent of the tw o groups (parents and professionals) is in d i cated by an asterisk placed beneath the highest value on the reproduc tions of the test illustrations and in the significance colum n in the Ta ble. The pictures that did not have adequate conformity in th e evalua tion, that is, m ean values betw een 151 and 249, do not have a symbol. In general, the dentists and or thodontists rated m ore of the test exam ples as abnormal th a n did the parents. An exception is picture 22 of a dentition that represents the “ugly duckling” stage of dental de velopm ent. For this exam ple (pic ture 22 ), there was also a significant difference registered betw een den tists and orthodontists. The latter more often scored picture 22 as norm al. The reverse w as true for profile picture 10 , in w hich more dentists found it acceptable than did orthodontists. For evaluations of bqth pictures 22 and 10 , the par ents were fairly uniform in their judgm ent. A greater consistency of rating was found for the profes210 ■ JADA, V ol. 98, February 1979
í V
y V
y
í
f( 7 + .r *
F ig 1 ■ L ine d ra w in g s o f fa c ia l p ro file s u s e d in e v a lu a tio n o f d e n to fa c ia l m o rp h o lo g y ; + m e a n s r a te d b y m a jo rity o f p a re n ts a s n o rm a l; - m e a n s r a te d b y m a jo rity o f p a r e n ts a s a b n o rm a l, re q u irin g tre a tm e n t; (+ ) m e a n s r a te d b y m a jo rity o f d e n tis ts a n d o rth o d o n tis ts a s n o rm a l; ( - ) m e a n s r a te d b y m a jo rity o f d e n tis ts a n d o rth o d o n tists a s a b n o rm a l, re q u irin g tre a tm e n t;* in d ic a te s s ig n ific a n t d if fe re n c e b e tw e e n p a re n ts ' a n d p ro fe s sio n a ls ’ e v a lu a tio n s , a n d is p la c e d u n d e r h ig h e s t value.
sional group. They were consistent in rating nine of the 11 facial profile \draw ings and nine of the 11 color photographs of the dentition. The averages and standard deviations in the Table allow com parison of the
rating given by the different groups. The data show interesting differ ences in the ratings of the different pictures as w ell as in the variation found in the judgm ent of the par ents and professionals.
ARTICLES
Discussion Results of the study indicate that a significant difference exists in the subjective evaluation of morphological characteristics in the dentofacial region between parents, dentists, and orthodontists. The observed differences are probably related to the differences among the three groups in knowledge of and experience in the subject. 2 Parents considered more pictures normal and acceptable than did the professional groups .3· 6 The differences between the dentists and orthodontists were small. It is assumed that the orthodontists considered the "ugly duckling" aspect of picture 22 as a normal developmental stage of the dentition. The higher rating of abnormality by orthodontists for picture 10 is probably related to the number of . orthodontists associating the profile with a Class II, Division 2, deep bite malocclusion similar to picture 15. Visual appearance was used as the only discriminating component in the determination of abnormality and the need for orthodontic treatment. Undoubtedly, the majority of the evaluators were influenced, consciously or subconsciously, by psychological, social, and other factors that they associated with the pictures.7- 9 The degree of handicapping accompanying dentofacial malformations is a combination of many factors and is related strongly to the person's psychosocial adjustment as well as to actual impairment of function or oral health. 1 <>- 12 Further, other considerations more readily assessable by dentists and orthodontists are essential in deciding whether treatment is indicated or desirable . These considerations include the state of oral hygiene, predisposition to caries, condition of the periodontium, the attitude of the patient and his motivation, and the actual need for orthodontic treatment. 13- 15 To determine the need for orthodontic treatment of a population and to distribute adequately the available manpower for the co"rrec-
Fig 2 • Dentitions used in evaluation. Symbols same as in Figure 1.
Table • Means and standard deviations for the values of responses by parents and by general dentists and orthodontists to drawings of facial profiles and photographs of dentitions.
No.
Mean
c·
SD
Dentists and orthodontists Mean SD Facial profile drawings
1 2 3 4 5 6 7 8 9 10
247 188 165 225 130 104 238 225 260 105 150
0 0 0 0
59 68 71 64 53 23 60 65 58 25 57
298 284 257 300 183 105 294 283 294 146 213
Parents
11
+ +
0 0
+ +
c
(-) (-) (-) (-) 0
(+)
(-! ~= (+
0
Differences between parents and professionals Significance' P value
13 37
X X
54
X X X
0 56 21 26 37 25 57 59
X X X X X
.0000 .0000 .0000 .0000 .0000 .7291 .0000 .0000 .0000 .0000 .0000
Color photographs of dentitions
12 13 14 15 16 17 18 19 20 21 22
276 206 228 292 230 142 290 267 183 224 297
0 0 0
+
0 0
50 73 72 29 66 65
32 51 73 67 18
288 296 237 299 263 135 292 273 290 244 262
(-) (-) 0
(- ) (+) (+)
(-) (-) (-) 0
(-)
33 20 53 9 48 53 27 48 32 54 58
X X X X
X X X
•c = Conformity in evaluation by majority of evaluators. = Significance of differences (P S .01).
t
tion of malocclusions, it must be realized that the image the layman has of a normal and abnormal dentofacial region differs significantly
from that of the professional who refers and treats malocclusions. Results of the study indicate that this is true at least in The Netherlands.
Prahl-Andersen-others : PERCEPTIONS OF DENTOFACIAL MORPHOLOGY • 211
.0092 .0000 .2005 .0061 .0000 .2343 .4930 .2055 .0000 .0015 .0000
A R T IC L E S
Summary Line draw ings of facial profiles and color photographs of dentitions w ere evaluated subjectively by 1,150 parents, 72 general practi tioners of dentistry, and 54 or thodontists w ith regard to the norm ality and abnorm ality in den tofacial m orphology and the need for orthodontic treatm ent. A significant difference was found b e tw e e n 'th e evaluations of the parents and the professional groups in ten of the 11 facial pro files and in seven of the 11 photo graphs of dentitions. In general, the parents considered more of the exam ples acceptable and not requiring orthodontic treatm ent than did the professional groups. The dentists and orthodon tists deviated significantly in their ratings only in their judgm ent of the “ugly d uckling” exam ple (picture 2 2 , h igher abnorm al rating by the dentists) and the profile example 10 (higher abnorm al rating by or thodontists). A num ber of orthodon tists may have associated the condi tion in picture 10 w ith a Class II,
212 m JADA, V ol. 98, February 1979
Division 2 m alocclusion and, as such, scored it abnormal.
T h is in v e stig atio n w as su p p o rte d in p a rt b y a g ra n t to th e N y m e g en G row th S tu d y from “ T he P rev e n tio n F u n d ,” th e H ague, T h e N e th er lan d s.
Drs. P ra h l-A n d erse n an d B oersm a are af filia te d w ith a n d Prof. v a n d e r L in d e n is h e ad o f th e d e p a rtm e n t of o rth o d o n tic s, U n iv ersity o f N y m eg en, T h e N e th erla n d s. Dr. M oore w as a F o g arty S e n io r In te rn a tio n a l F ello w a n d is p ro fesso r o f o rth o d o n tic s, U n iv e rsity o f W ash in g to n . S eattle. A d d re ss re q u e sts for re p rin ts to Dr. P rah l-A n d erse n . D epartm ent of O rth o d o n tic s, S ch o o l of D e ntistry, U n iv e rsity of N y m eg en . P h ilip s v a n L eydenlaan 25, N y m egen, T h e N e th erla n d s.
1. P rah l-A n d erse n , B., a n d K ow alski, C.J. A m ix ed lo n g itu d in a l, in te rd is c ip lin a ry stu d y of th e g ro w th a n d d e v e lo p m e n t o f D utch c h il dren . G ro w th 37:281-295, 1973. 2. S eco rd, P.F., a n d B ackm an, C.W. M aloc c lu sio n a n d p sy ch o lo g ica l factors. JADA 59:931-938, 1959. 3. In g erv all, B., a n d H edegard, B. A w are n e ss o f m a lo c c lu s io n a n d d e sire of o rth o d o n tic tre a tm e n t in 18-year-old S w e d ish m en. A cta O d o n to l S c a n d 32:93-101, 1974. 4. In g erv all, B. P rev a le n c e of d e ntal a n d oc c lu sa l a n o m a lies in S w e d ish c o n sc rip ts. A cta
O d o n to l S c a n d 32:83-92, 1974. 5. L in d eg a rd , B., a n d o thers. N eed a n d d e m a n d for o rth o d o n tic tre a tm e n t. T a n d la e g e b la d et 75(12}:1198-1210, 1971.
6. Shaw, W.C.; Lewis, H.G.; and Robertson, N.R. P e rc e p tio n o f m a lo c clu sio n . Br D ent J 138(6):211-216, 1975. 7. B eier, E.G., a n d others. R esponse to th e h u m a n face as a s tan d a rd stim u lu s: re e x am in atio n . J C onsult Psych 21(2):165-170, 1957. 8. F isk, R.O. P h y sio lo g ical an d so cio p sy c h o lo g ic al sig n ific a n ce o f m alo c clu sio n . J C an D ent A ssoc 29(l):635-643, 1963. 9. M acgregor, F.C. Social an d p sy ch o lo g ica l im p lic a tio n s o f d e ntofacial d isfig u re m e n t. A ngle O rth o d 40{3):231-233, 1970. 10. C lifford, E. P sychological a sp e c ts of o rofacial an o m alies: S peculations in s e a rc h of data. A SH A R eport no. 8, 1973. 11. C ohen, L.K. Social psych o lo g ical factors a sso c iated w ith m alo cclu sio n . Int D ent J 20:643-653, 1970. 12. Cox, N .H ., a n d V an d e r L in d en , F.P. Fa cial h a rm o n y . A m J O rthod 60:175-183, 1971. 13. K ow alski, C.J., a n d Prahl-A ndeT sen, B. S e le c tio n o f d e n to fa c ial m e a su re m e n ts for an o rth o d o n tic tre a tm e n t p rio rity in d e x . A ngle O rth o d 4 6 (l):94-97. 1976. 14. P rah l-A n d erse n , B., a n d B oersm a, H. De b e h o efte a an o rth o d o n tisc h e b e h a n d e lin g e n bij e en N ijm eegse p o p u la tie v a n 10, 5 jaar o u d e k in d e re n . N ed T ijd sc h r T a n d h e e lk 80:308-311, 1973. 15. S trieker, G. P sy ch o lo g ical issu e s p e r ta in in g to m a lo c clu sio n . A m J O rth o d 58(3):276-283, 1970.