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progress in orthodontics 1 3 ( 2 0 1 2 ) 42–48
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Original article
A Controlled Study on Diagnostic and Prognostic
Measurements of Palatally Displaced Canines
on Lateral Cephalograms
Heidi M. Novak a , Tiziano Baccetti b,∗ , Lauren M. Sigler a , James A. McNamara Jr. c
a
Research Assistant, Department of Orthodontics and Pediatric Dentistry, School of Dentistry,
The University of Michigan, Ann Arbor, USA
b Assistant Professor, Department of Orthodontics, The University of Florence, Florence, Italy;
Thomas M. Graber, Visiting Scholar, Department of Orthodontics and Pediatric Dentistry, School of Dentistry,
The University of Michigan, Ann Arbor, USA
c Thomas M. and Doris Graber, Endowed Professor of Dentistry, Department of Orthodontics and Pediatric Dentistry,
School of Dentistry; and Research Professor, Center for Human Growth and Development, The University of Michigan, Ann Arbor, USA
a r t i c l e
i n f o
a b s t r a c t
Article history:
Objectives: The aim of this prospective controlled study was to determine the role that the
Received 12 July 2011
lateral cephalogram can play in the detection of palatally displaced canines (PDCs).
Accepted 13 July 2011
Materials and methods: The study was comprised of 85 subjects in the late mixed dentition.
Thirty-five subjects had PDCs (either unilateral or bilateral) identified on the panoramic
Keywords:
radiograph (PDC group), and 50 subjects presented with a normal pathway of upper per-
Diagnosis
manent canine eruption as assessed on panoramic radiographs (No-PDC group). Linear and
Displaced canines
angular measurements on the lateral cephalograms concurrent with panoramic radiographs
Impacted canines
were compared between the PDC and No-PDC group statistically.
Lateral cephalogram
Results: All angular measurements that incorporated the main axis of the canine (to Frankfort
horizontal, to the palatal plane, or to the axis of the central incisor) were significantly smaller
in the PDC group (p<0.001). In terms of linear measurements, both the distance from the tip
of the canine to the vertical axis of the central incisor parallel to Frankfort horizontal and
the distance from the tip of the canine to the anterior alveolar ridge parallel to Frankfort
horizontal showed significantly larger values in the PDC subjects than in normal controls.
On the contrary, the vertical distance from the tip of the canine to the functional occlusal
plane did not reveal any significant difference between the PDC and the No-PDC group.
Conclusions: Early diagnosis of PDC is essential in order to avoid the occurrence of final canine
impaction. If 3-D images of a displaced canine cannot be acquired, a lateral cephalogram can
be a useful tool for the early detection of PDC in the late mixed dentition. The angle between
the vertical axis of the canine and the palatal plane demonstrate diagnostic value when
assessing PDCs. Values for this angle smaller than 102 degrees can indicate the presence of
PDC.
© 2011 Società Italiana di Ortodonzia SIDO. Published by Elsevier Srl. All rights reserved.
∗
Corresponding author. Department of Orthodontics, University of Florence, Via del Ponte di Mezzo 46-48 – 50127 Florence, Italy.
E-mail address: tbaccetti@unifi.it (T. Baccetti).
1723-7785/$ – see front matter © 2011 Società Italiana di Ortodonzia SIDO. Published by Elsevier Srl. All rights reserved.
doi:10.1016/j.pio.2011.07.001
progress in orthodontics 1 3 ( 2 0 1 2 ) 42–48
1.
Introduction
Natural history studies have reported 0.2 to 2.3 percent of
orthodontic populations to have at least one impacted maxillary canine tooth.1 In European populations, approximately
85% of maxillary canine impactions are oriented palatally.1,2
Palatal maxillary canine impaction is thought to have a genetic
etiology.3 The pathogenesis of palatal canine impaction is
characterized by an early developmental stage that can be
reversed with treatment. At this stage, the canine is considered to be a “palatally displaced canine (PDC),” as it presents
with an intraosseous palatal position prior to expected time
of eruption.1
If left untreated, PDCs generally progress to impaction
after the pubertal growth spurt and will require surgical
intervention.4,5 Recent studies reported prevalence rates for
impaction of PDCs ranging from 75-85%.6,7 Failure to recognize and treat maxillary canine displacement may result in
root resorption of adjacent teeth8–10 and/or the formation of
cysts.11–13 Furthermore, patients with PDCs that progress to
impaction will incur higher treatment costs, more complex
treatment plans, and delayed treatment timetables.14,15
Early interceptive treatment measures of PDCs aimed to
prevent the final occurrence of maxillary canine impaction
have been proven to be effective. These treatments include
deciduous canine extraction that may be coupled with protocols that include molar distalization and/or treatment for
Class II or Class III tendencies and/or treatment for mildto-moderate tooth-size/arch-size discrepancies.7,16–19 Early
detection and adequate evaluation of the PDC condition
is a necessary prerequisite for each of these treatment
approaches. Currently, PDCs are detected most commonly
by assessing maxillary canine position using panoramic
radiographs.11 Using these radiographs, a PDC is characterized
by an increased angle between the main axis of the canine
and the midline and/or the cusp overlapping the ipsilateral
central or lateral incisors.9 Diagnosis of PDC on panoramic
radiographs is recommended in the late mixed dentition after
the age of 10 years, while earlier evaluation does not appear
to be reliable due to developmental processes in the eruption
of the permanent canine.7,11,20 During the same age period,
panoramic radiograph evaluation for PDCs can be supplemented by digital palpation of the maxillary canine region.21,22
The lateral cephalogram also is a type of radiograph that
can supplement detection of palatally displaced canines. The
lateral cephalogram, that are part of the standard radiographic
records for orthodontic treatment planning, can provide
additional information about the location and severity of displacement of upper permanent canines with an anomalous
eruption pathway. However, there have been hardly any studies as to the role the lateral cephalograms can play potentially
in describing the intraosseous position of PDCs. One study by
Orton et al.23 used lateral cephalograms to investigate root
resorption caused by unerupted palatal canines. The study
included the angle of the coronal vertical axis of the canine
to the Frankfort horizontal, the distance between the apex of
the canine and the occlusal plane, and canine sagittal position to evaluate the ability of an ectopic canine in causing root
resorption.
43
The goal of the present prospective controlled study was
to evaluate the use of measurements on lateral cephalograms
for overall PDC detection in the late mixed dentition.
2.
Materials and methods
The study included subjects from a two-center prospective
clinical trial at the Department of Orthodontics and Pediatric
Dentistry of the University Michigan and the Department of
Orthodontics at the University of Florence, Italy, between 1985
and 2009. Enrollment criteria for subjects in the trial were as
follows:
• Caucasian ancestry;
• age range from 9.5 to 13.0 years;
• late mixed dentition stage;
• stage of skeletal growth ranging from CS1 to CS4 as evaluated on lateral cephalograms according to the cervical
vertebral maturation method;24
• absence of previous orthodontic treatment; and,
• absence of supernumerary teeth, odontomas, cysts, craniofacial malformations, or sequelae of traumatic injuries.
The study sample included 85 subjects with the listed
features above. Thirty-five of them had PDCs (either unilateral or bilateral) identified on the panoramic radiograph (PDC
group), while 50 subjects presented with a normal pattern
of upper permanent canine eruption pathway as assessed
on panoramic radiographs (No-PDC group). Informed consent
was signed by the parents of all subjects enrolled in the trial
in both of the research sites.
2.1.
Diagnostic Measurements at T1
The following measurements proposed by Ericson and Kurol11
were performed on panoramic radiographs of all subjects
(Fig. 1):
• alpha angle: mesial inclination of the crown of the permanent canine to the midline (Fig. 1A);
• d distance: distance of the cusp tip of the permanent canine
to the occlusal line (Fig. 1B);
• sector: indicating the mesial position of the crown of the displaced canine with respect to the central and lateral incisors
(5 sectors, with sector 1 indicating the position of the crown
of the displaced canine posterior to the distal aspect of
the lateral incisor and sector 5 in correspondence with the
mesial half of the upper central incisor) (Fig. 1C).
As indicated by Ericson and Kurol,11 these measurements
are valid diagnostic variables for PDC within the age range
studied in this trial. Palatal displacement of the canine(s) was
confirmed by means of Clark’s tube shift rule using multiple
intraoral radiographs of the canine region.25
Lateral cephalograms of all subjects concurrent with
the panoramic radiographs were analyzed. The following
measurements were performed on the lateral cephalograms
(Fig. 2):
• Angle of the vertical axis of the canine to the Frankfort plane
(VAC-FH, degrees);
• Angle of the vertical axis of the canine to the palatal plane
(VAC-PP, degrees);
44
progress in orthodontics 1 3 ( 2 0 1 2 ) 42–48
Fig. 1 – Measurements of canine position on a panoramic radiograph. A) alpha angle; B) d distance; C) sector.
• Angle of the vertical axis of the canine and the vertical axis
of the central incisor (VAC-VAI, degrees);
• Distance from the tip of the canine to the vertical axis of the
central incisor parallel to Frankfort horizontal (dC-VAI, mm);
• Distance from tip of the canine to the anterior alveolar
ridge parallel to Frankfort horizontal (dC-AAR, mm);
• Distance from the tip of the canine to the functional
occlusal plane (dC-FOP, mm) (Fig. 3).
The magnification factor for the panoramic films in both
groups was 18%, while the magnification factor of the lateral
cephalograms was 8%.
2.2.
Fig. 2 – Measurements of canine position on a lateral
cephalogram: A. Angle of the vertical axis of the canine to
the Frankfort plane (VAC-FH, degrees); B. Angle of the vertical
axis of the canine to the palatal plane (VAC-PP, degrees);
C. Angle of the vertical axis of the canine and the vertical
axis of the central incisor (VAC-VAI, degrees); D. Distance
from the tip of the canine to the vertical axis of the central
incisor parallel to Frankfort horizontal (dC-VAI, mm);
E. Distance from tip of the canine to the anterior alveolar
ridge parallel to Frankfort horizontal (dC-AAR, mm);
F. Distance from the tip of the canine to the functional
occlusal plane (dC-FOP, mm).
Power of the Study and Method Error
The estimate of the power of the study was performed before
the beginning of the clinical part of the trial. Taking into consideration the standard deviations of the diagnostic measures
on the panoramic radiographs from a previous study7 and the
use of non-parametric or categorical statistics, the calculated
power of the study exceeded 0.90 at an alpha=0.05 with the
sample sizes of 50 subjects and 35 subjects in the 2 examined
groups, respectively.
Accuracy of measurements on panoramic radiographs
was calculated using the Dahlberg’s formula26 on measures
repeated on 15 subjects selected randomly from the two
groups. The method error was smaller than 1.5◦ for angular
measures, and smaller than 1 mm for the linear distances.
The appraisal of the sector of canine displacement showed
a reproducibility of 100%.
2.3.
Statistical analysis
The descriptive statistics for demographic data (age and
gender) as well measurements on panoramic films and
lateral cephalograms comparisons were carried out with
progress in orthodontics 1 3 ( 2 0 1 2 ) 42–48
45
10 years 3 months ± 10 months. The No-PDC group was comprised of 26 female subjects and 24 male subjects, and the
PDC group was comprised of 24 female subjects and 11 male
subjects.
The descriptive statistics for the measurements on
panoramic films in the 2 groups is reported in Table 2. There
was a statistically significant difference in both alpha angle
and sector between the No-PDC group and PDC group, with
the PDC group showing greater values for the angle and more
severe sectors of displacement. No statistically significant difference between the 2 groups was found for the d distance.
The descriptive statistics for the measurements on lateral
cephalograms in the 2 groups. The VAC-FH and the VAC-PP
angles were significantly smaller in the PDC group (about
-6 degrees and -12.8 degrees, respectively). The VAC-VAI angle
was significantly smaller in PDC subjects as well (-4.8 degrees
difference). The dC-VAI and the dC-AAR distances showed
significantly greater values in the PDC group (5.4 mm and
3.9 mm) than in the No-PDC group. No significant difference
was assessed for the dC-FOP distance between the 2 groups.
4.
Fig. 3 – Graphical illustrations of the average intraosseous
position of the upper permanent canine in the PDC
group (A) and in the No-PDC group (B).
Mann-Whitney U tests (p<0.05) for metric measures and with
chi-squared tests (p<0.05) for categorical measures. Statistical
analysis was performed with statistical software (Statistical Package for the Social Sciences, SPSS, Version 16.0.1
Chicago, IL).
3.
Results
The mean age (Table 1) for the No-PDC group was 10 years
2 months ± 6 months. The mean age for the PDC group was
Discussion
Early diagnosis of PDC is required in order to plan adequate
interceptive approaches that may prevent the occurrence of
final canine impaction. PDCs are detected most commonly
by assessing maxillary canine position using panoramic
radiographs,11 and this assessment is usually supplemented
by digital palpation of the maxillary canine region.21,22
Although lateral cephalograms are needed regularly for
orthodontic treatment planning, the literature is lacking studies on the role of this diagnostic tool in describing the
intraosseous position of PDCs, with the exception of Orton
et al.23 who used lateral cephalograms to investigate root
resorption caused by palatally impacted canines. The study
included the angle of the coronal vertical axis of the canine
to the Frankfort horizontal, the distance between the apex of
the canine and the occlusal plane, and canine sagittal position to evaluate the ability of an ectopic canine in causing root
resorption. The aim of the current study was to evaluate the
information derived from lateral cephalograms for overall PDC
detection in the late mixed dentition.
Both the alpha angle and sector measurements on a
panoramic radiograph in the late mixed dentition confirmed
their diagnostic value in detecting PDCs.20 There was an
average difference in alpha angle between PDC and No-PDC
subjects of about 20 degrees, with the angle significantly
greater in the PDC group. In terms of sector of intraosseous
position, the No-PDC group did not present any maxillary
canine in sectors 3 or 4, while the percentage of PDC cases
showing displacement of the canine in these sectors was 34%.
The measures on the lateral cephalograms corresponding
to the panoramic radiographs provided significant information regarding the palatal displacement of the canines in the
PDC subjects. All angular measures describing the inclination
of the main axis of the canine to the Frankfort plane, or to the
palatal plane, or to the axis of the central incisor were significantly smaller in the PDC group. The values derived from the
No-PDC group can be used as reference values when assessing the relative position of the canine on a lateral cephalogram
46
progress in orthodontics 1 3 ( 2 0 1 2 ) 42–48
Table 1 – Descriptive statistics for the measurements on panoramic films and between-group comparisons
PDC Group
n =35
Panoramic Radiographic Measures
Mean
Alpha angle
d distance
SD
27.5
17.0
9.7
3.6
Number of Cases
Sector 1
Sector 2
Sector 3
Sector 4
No-PDC Group
n = 50
Percentage
8
15
8
4
PDC vs No-PDC
Mean
SD
MW-Test
7.6
14.1
3.9
3.1
***
NS
Number of Cases
Percentage
46
4
0
0
92%
8%
0%
0%
23%
43%
23%
11%
Chi-squared test
***
*** p<0.001; NS=not significant.
during the mixed dentition. It should be pointed out, however,
that the measures of canine inclination that include the main
axis of the central incisor may be strongly influenced by the
relative inclination of this tooth to the craniofacial structures.
Similar considerations can be made with regard to the inclination of the maxillary canine to FH, as this variable can be
influenced by the relationships between FH and the maxillary bone. More reliable information regarding the position of
the upper permanent canine within the maxillary bony structures can be derived from the analysis of the inclination of
the canine to the palatal plane. Subjects showing PDC exhibit,
on average, a VAC-PP angle which is about 13 degrees smaller
than subjects with a normal eruption pattern of the canine.
The decreased angulation of the canine relative to the palatal
plane indicates the palatal displacement of the crown of the
tooth. The “effect size” (the ratio between the mean betweengroup difference and the mean of the standard deviations
of the two groups)27 for the comparison between PDC and
No-PDC subjects as to the VAC-PP angle was highly significant (>2). This means that the between-group difference was
significantly greater than the individual variability within the
groups when assessing the value for the angular measure,
thus demonstrating the diagnostic validity of this variable.
The findings of the present study can be compared with
those of the report by Orton et al.23 limited to the use of the
angle between the vertical axis of the canine and the Frankfort
horizontal. In the previous study, the authors identified as
normal eruption pathway an inclination of the canine relative
to FH of 100 to 115 degrees. These values are similar to the
findings of the current investigation, as we found the canine
to be normally located within the bony structures when the
VAC-FH angle was between 99.7 to 116.3 degrees.
As for the distances, both the dC-VAI and the dC-AAR measures showed significantly larger values in the PDC subjects
than in normal controls. However, these results were expected
on the basis of the between-group differences in the previously
reported angular measurements. On the contrary, the vertical distance dC-FOP did not reveal any significant difference
between PDC and No-PDC groups. This finding confirmed also
the lack of diagnostic value of the d distance on panoramic
radiographs.
The recent development of low-dose or cone-beam
computerized tomography is improving significantly the possibility to appraise the intraosseous position of maxillary
canines in growing subjects. However, in the lack of 3-D imaging locating the canine within the maxillary bony structures,
Table 2 – Descriptive statistics for the measurements on lateral cephalograms
PDC Group
n = 35
No-PDC Group
n = 50
PDC vs No-PDC
Lateral Cephalogram Measures
Mean
SD
Mean
SD
Vertical axis of the canine and the
Frankfort plane (VAC-FH ◦ )
Vertical axis of the canine to the palatal
plane (VAC-PP◦ )
Vertical axis of the canine to the vertical
axis of the central incisor (VAC-VAI◦ )
Cusp tip of the canine to the axis of the
central incisor, parallel to Frankfort
horizontal (dC-VAI, mm)
Cusp tip of the canine to the anterior
alveolar ridge, parallel to Frankfort
horizontal (dC-AAR, mm)
Cusp tip of the canine perpendicular
to the occlusal plane (dC-FOP, mm)
102.1
5.9
108.0
6.3
-5.9
***
96.4
5.7
109.2
6.5
-12.8
***
3.2
2.6
8.0
6.7
-4.8
***
9.6
4.2
4.2
2.1
5.4
***
12.8
4.3
8.9
2.3
3.9
***
10.4
2.4
10.0
3.1
0.4
NS
***p<0.001; NS=not significant.
Mean Difference
MW-Test
progress in orthodontics 1 3 ( 2 0 1 2 ) 42–48
the use of a lateral cephalogram appears to be a valuable
adjunct for the diagnosis of PDC in late mixed dentition
patients.
5.
Conclusions
The lateral cephalogram is able to provide useful information
regarding the intraosseous position of maxillary permanent
canines in the late mixed dentition that can supplement
indications derived classically from panoramic radiographs.
Among a series of angular and linear measures on a lateral
cephalogram, the angle between the vertical axis of the canine
and the palatal plane demonstrate diagnostic value when
assessing PDCs. Values for this angle smaller than 102 degrees
can indicate the presence of PDC.
Conflict of interest
The authors have reported no conflicts of interest.
Riassunto
Obbiettivi: L’obbiettivo di questo studio prospettico controllato
è stato quello di determinare il ruolo che la teleradiografia in
proiezione latero-laterale può avere nell’identificazione del dislocamento palatino dei canini (PDC).
Materiali e metodi: Lo studio ha analizzato 85 soggetti in fase di
dentatura mista tardiva. Trentacinque soggetti presentavano PDC
(mono- o bilaterale) identificato sulla ortopantomografia (gruppo
PDC) e 50 soggetti presentavano un percorso eruttivo normale
dei canini superiori permanenti valutato sulla ortopantomografia
(gruppo No-PDC). Misurazioni lineari ed angolari sulle teleradiografie latero-laterali corrispondenti alle ortopantomografie sono state
confrontate statisticamente tra i due gruppi.
Risultati: Tutte le misurazioni angolari che comprendevano l’asse
del canino (rispetto al piano di Francoforte, al piano palatino, e
all’asse dell’incisivo centrale) erano significativamente minori nel
gruppo PDC (p<0.001). Per quanto riguarda le misurazioni lineari
le distanze parallele al piano di Francoforte dalla cuspide del canino
all’asse dell’incisivo centrale e dalla cuspide del canino al margine
alveolare anteriore erano significativamente maggiori nei soggetti
con PDC. La distanza verticale dalla cuspide del canino al piano
occlusale funzionale non mostrava differenze significative nei due
gruppi.
Conclusioni: La diagnosi precoce di PDC è fondamentale per evitare
l’inclusione del canino permanente. Se non è possibile acquisire
immagini tridimensionali di un canino in malposizione intraossea,
una teleradiografia in proiezione latero-laterale può essere utile per
identificare precocemente il dislocamento palatino del canino in fase
di dentatura mista tardiva. L’angolo tra l’asse del canino e il piano
palatino si è dimostrato di valore diagnostico nella valutazione del
dislocamento palatino del canino permanente. In particolare, valori
per quest’angolo inferiori a 102 gradi possono indicare la presenza
di PDC.
Résumé
Objectifs: Cette étude contrôlée prospective vise à préciser le rôle
que le céphalogramme latéral peut jouer dans la détection de canines
incluses en palatin (PDCs).
47
Matériels et méthodes: L’étude a porté sur 85 patients en denture
mixte tardive. Trentecinq sujets avaient des canines incluses en
palatin (uni ou bilatérales) identifiées à l’aide de radiographies
panoramiques (groupe PDC) et 50 sujets présentaient une evolution
normale de l’éruption de la canine permanente supérieure comme le
montrent les radiographies panoramiques (groupe non- PDC). Comparaison des mesures angulaires et linéaires des céphalogrammes
latéraux et en même temps des radiographies panoramiques entre
le groupe PDC et le groupe non-PDC, à des fins statistiques.
Résultats: Toutes les mesures angulaires qui comprenaient l’axe
principal de la canine (plan horizontal de Francfort, plan palatin, ou
bien l’axe de l’incisive centrale) faisaient état de valeurs nettement
plus faibles dans le groupe PDC (p. <0,001). En termes de mesures
linéaires, la distance de l’apex de la canine à l’axe vertical de l’incisive
centrale parallèle au plan horizontal de Francfort et la distance de
l’apex de la canine au bord alvéolaire antérieur parallèle au plan
horizontal de Francfort faisaient état de valeurs nettement plus
élevées chez les sujets PDC que dans le groupe de contrôle. Par contre,
la distance verticale de l’apex de la canine au plan occlusal fonctionnel ne montrait aucune différence significative entre le groupe PDC
et le groupe non-PDC.
Conclusions: Un diagnostic précoce de canine incluse en palatin
est fondamental dans le but d’éviter l’apparition d’une inclusion de
canine. Si l’imagerie en 3D d’une canine incluse ne peut être obtenue,
un céphalogramme latéral peut s’avérer un bon outil pour une détection précoce de PDC dans la denture mixte tardive. L’angle entre l’axe
vertical de la canine et le plan palatin ont une valeur de diagnostic
lorsqu’on aborde des situations de canines incluses en palatin. A
cet effet, des valeurs inférieures à 102 degrés peuvent indiquer la
présence de canines incluses en palatin.
Resumen
Objetivos: Se realizó este estudio controlado prospectivo para determinar el papel que el cefalograma lateral puede jugar en la detección
de caninos impactados por palatino (PDCs).
Materiales y métodos: el estudio abarcó a 85 sujetos en la fase
de dentición mixta tardía. Treinta y cinco sujetos tenían caninos
impactados por palatino (unilateral o bilateral), identificados por
radiografias panorámicas (Grupo PDC) y 50 sujetos presentaban un
camino normal de la erupción del canino superior permanente como
se desprendía de las radiografías panorámicas (grupo no-PDC). Se
llevó a cabo la comparación de las mediciones lineales y angulares de
los cefalogramas laterales y al tiempo de las radiografías panorámicas entre el grupo PDC y el grupo no-PDC a fines estadísticos.
Resultados: Todas las mediciones angulares que abarcaban el eje
principal del canino (plano horizontal de Frankfort, plano palatal, o
eje del incisivo central) resultaron tener valores netamente inferiores
en el grupo PDC (p<0.001). En términos de mediciones lineales,
tanto la distancia del tip del canino al eje vertical del incisivo central
paralelo al plano horizontal de Frankfort y la distancia del tip del
canino al margen alveolar anterior paralelo al plano horizontal de
Frankfort experimentaron valores significativamente más altos en
los sujetos con caninos impactados por palatino que en el grupo de
control. En cambio, la distancia vertical del tip del canino al plano
oclusal funcional no experimentó diferencia significativa entre el
grupo PDC y el grupo no-PDC.
Conclusiones: Un diagnóstico precoz de PDC es básico para evitar
la aparición de una impactación de canino. Si no es posible conseguir
imágenes en 3D de un canino impactado, un cefalograma lateral
48
progress in orthodontics 1 3 ( 2 0 1 2 ) 42–48
puede ser una buena herramienta para una detección temprana de
PDC en la dentición mixta tardía. El ángulo entre el eje vertical del
canino y el plano palatino demuestra que tiene valor de diagnóstico
cuando se valoren situaciones de caninos impactados por palatino.
Valores inferiores a 102 grados pueden indicar presencia de PDC.
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