Download this PDF file

International Journal of Contemporary Orthodontics
doi: 10.1013/IJCO/1701-0002
Original Research
Assessment of Tip, Torque and Tooth Size Discrepancies In
Angles Class II Division-2 Patients
Gaurav Patil 1, Dhruvi Pradhan2, Ridima Gupta2, Amol Patil 2
1
2
Private Practise, Pune, Maharashtra, India
Bharati Vidyapeeth Dental College and Hospital, Pune, Maharashtra, India
Abstract
Objective: To evaluate the tip and torque values of patients with angles class II division 2 malocclusion and compare
values obtained with those from Andrews and other studies and see the variance or similarity if any.
Materials and methods: Models of maxillary and mandibular arch are prepared. The measurement was done by
protractor device with adjustable readout arm and Boley gauge with sharpened points. The facial axis-point were
marked on each crown of the maxillary and mandibular arch. The facial axis clinical is the reference line from which
crown angulations and inclinations are measured.
Results - Positive tip values were obtained for all the maxillary teeth except the maxillary second molar.
incisors, canines and molars were less angulated. Negative tip values were obtained for mandibular incisors, canines
and first premolars
Introduction
Orthodontists treat various malocclusions of the jaws and aims
at establishing esthetic, functional and harmonious occlusion.
The emphasis at present is on treating the face as a whole and
not just the occlusion; however, the importance of achieving an
ideal occlusion that is in harmony with the face has not
diminished since the time of Dr. E.H. Angle.
The most comprehensive and exhaustive study to
understand the relationship of teeth was undertaken by Andrews
in 1964. He made extensive measurements on 120 non
orthodontic normal casts of white North American origin to
develop his "six keys to normal occlusion”.
The presence of disproportionately sized teeth in either
maxillary or mandibular arch can make it difficult to obtain an
occlusion with good alignment, ideal overjet, ideal overbite, and
Correspondence: Gaurav Patil, MDS
Private Practice Pune
Email [email protected]
a Class I molar relationship. In order for the maxillary teeth to
fit well with the mandibular teeth, a definite proportionality of
tooth size should exist. Therefore, the ability to analyze the
proportionality of the maxillary and mandibular teeth is an
important diagnostic tool at the initial stages of treatment.
There is a need to establish the tip and torque values for
class II division 2 patients to find out if they are comparable or
in variance with those established by Andrews, which forms the
basis of the bracket prescription of most pre-adjusted edgewise
appliance systems.
The present study was carried out to study tip, torque
and tooth size discrepancy values in subjects exhibiting class II
div2 malocclusion and no previous history of orthodontic
treatment. In addition the data was compared to that of original
research values of Andrews.
Materials and methods
30 patients selected who are diagnosed as having Angles class
II division 2 malocclusion (Fig.1). Subjects are selected from
the sample that was initially screened through purposive
Patil et al.
Vol. 1 Issue 1
Fig 2:Protractor positioned on the trimmed cast to measure crown tip
Fig 1: Representation of occlusion of Class II division 2 subjects
sampling technique. The screened subjects who fulfilled the
selection criteria were selected.
Selection Criteria:
Inclusion Criteria:
1.
2.
3.
Subjects in the age group of 14- 30 years.
Subjects having Angles class II division 2
malocclusion.
No history of orthodontic treatment.
Exclusion Criteria:
1.
2.
Angles Class I, Class II division 1 and class III
molar relation.
Subjects with craniofacial anomalies.
Method of Collection of Data:
Alginate impressions of 30 subjects who satisfied the above
mentioned criteria were made for both maxillary and
mandibular arches, poured with orthokal and study models
prepared and Protractor device with adjustable readout
arm was used for measurement of Tip, Torque and Tooth Size
as follows: the base of the protractor was placed on the
occlusion plane, parallel to a line that would connect the contact
points of the crown being measured. The protractor readout arm
was adjusted parallel the crown's FACC. The angulation of
the crown was read from where the line of the read out arm
fell on the protractor's scale (Fig.2).
Crown Inclination / Torque:
The protractor was positioned at right angles to line
that would connect the contact points of the crown being
measured. The protractor's read out arm was adjusted to
parallel and tangent to the FACC at facial axis point, and the
inclination the crown was read on the protractor's scale (Fig.3).
Tooth Size Discrepancies:
Bolton analysis was used to determine disproportion
in size between maxillary and mandibular teeth.First, the
individual mesiodistal measurements of all teeth from the
first molars mesially were recorded. Tooth size
measurements were taken with a sharp pointed Boley gauge,
measuring the widest mesiodistal dimension of each tooth
as described by Bolton. Next, the determination of tooth size
discrepancy was made according to the method outlined by
Bolton.
The overall ratio as calculated from the greatest
mesiodistal measurement of the teeth in each arch from first
molar to first molar. The anterior ratio was calculated from
greatest mesiodistal measurement of the six anterior teeth in
each arch.
Method of Measurements:
The measurements were carried out by using protractor
with adjustable read out .
The facial axis of clinical crown and its midpoint,
the facial axis-point were marked on each crown of the both
maxillary and mandibular arch. The facial axis clinical
crown is the reference line from which crown angulation and
inclination are measured.
Crown Angulation/tip:
Sum mandibular “12”
Overall ratio = ---------------------------------------------- x 100
Sum
maxillary “12”
Sum mandibular “6”
----------------------------------------------- x 100
Sum maxillary “6”
The mean, median, range, standard deviation were calculated
for both overall "12" ratio and anterior "6" ratio.
Anterior ratio =
The procedure of measuring each of the cast is
International Journal of Contemporary Orthodontics
2
Vol. 1 Issue 1
.
Patil et al.
Fig 3: Protractor positioned on the trimmed cast to measure crown torque
Statistical analysis
Measurements are presented as Mean ± SD and range values.
95% confidence limits are found for each tooth separately
and are presented along with mean and standard deviation.
Table 2: Inclination / Torque values
Maxillary arch:
Maxillary central incisors: The mean tip values were found to
be 1.48° with a SD of 5.31 and a range of -11 to 13°.
Results
The aim of the present study is to assess the tip/torque
and tooth size discrepancies of Class II division 2 patients. From
sample of 30 casts, tip and torque measurements were carried
out as described by Andrew's. Anterior and posterior tooth size
ratios were determined as described by Bolton. The results are
as follows
Angulations/tip values: Mean values were found from the 30
subjects as shown in Table 1
Maxillary lateral incisors: The mean tip values were found to
be 7.4°with a SD of 5.85 and a range of -17 to 24° .
Maxillary canines: The mean tip values were found to be 6.45°
with a SD of 8.83 and a range of -11 to 35°.
Maxillary first premolars: The mean tip values were found to
be 5.18° with a SD 4.97 and a range of -5 to 14° .
Maxillary second premolars: The mean tip values were found
to be 5.05° with a SD of 6.23 and a range of -10 to 20° .
Maxillary first molars: The mean tip values were found to be
4.78° with a SD of 5.04 and a range of -7 to 13° .
Maxillary second molars: The mean tip values were found to
be -1.89° with a SD of 7.42 and a range of -15 to 12°.
Mandibular arch:
Mandibular central incisors: The mean tip values were found
to be -0.94° with a SD 3.97 and a range of -10 to 6°.
Mandibular lateral incisors: The mean tip values were found
to be -2.33° with a SD 4.71 and a range of -15 to 9°.
Mandibular canines: The mean tip values were found to be 2.8° with a SD 4.98 and a range of -21 to 9° .
Table 1: Angulation / Tip values
Mandibular first premolars: The mean tip values were found
to be -1.7° with a SD 3.59 and a range of -10 to 5°.
Mandibular second premolars: The mean tip values were
found to be 0.93° with a SD 3.61 and a range of -7 to 8°.
3
International Journal of Contemporary Orthodontics
Patil et al.
Vol. 1 Issue 1
Table 3: Boltons Analysis
Mandibular first molars: The mean tip values were found to
be 3.13° with a SD 3.41 and a range of -15 to 10°.
Mandibular second molars: The mean tip values were found
to be 6.64° with a SD 5.49 and a range of -13 to 20°.
Inclinations/torque values : Mean values were found from the
30 subjects as shown in Table 2
Maxillary arch
Maxillary central incisors: The mean torque values were found
to be -10° with a SD 6.98 and a range of -25 to 8°.
Maxillary lateral incisors: The mean torque values were found
to be 5.4° With a SD 8.35 and a range of -14 to 20°.
Maxillary canines: The mean torque values were found to be 1.57° with a SD 6.28 and a range of -13 to 10°.
Table 5: Comparison of Mandibular arch parameters between study group and
Andrews
Data (Mean
±SD)
Mandibular
arch:
Mandibular central incisors: the mean torque values were
found to be -2.26° with a SD 6.08 and a range of -17 to 10°.
Mandibular lateral incisors: the mean torque values were
found to be -1.98° with a SD 5.33 and a range of -15 to 10°.
Mandibular canines: the mean torque values were found to be
-4.48° with a SD 5.41 and a range of -15 to 7°.
Mandibular first premolars: the mean torque values were
found to be -6.68° with a SD 5.41 and a range of -19 to 10°.
Mandibular second premolars: the mean torque values were
found to be -8.68° with a SD 4.56 and a range of -20 to 0°.
Mandibular first molars: the mean torque values were found
to be -14.23° with a SD 5.53and a range of -30 to -4°.
Maxillary first premolars: The mean torque values were found
to be -4.1° with a SD 4.59 and a range of -6-9° and a range of 13 to 4°.
Mandibular first molars: the mean torque values were found
to be -14.23° with a SD 5.53and a range of -30 to -4°.
Maxillary second premolars: The mean torque values were
found to be -6.06° with a SD 4.24 and a range of -15 to 4°.
Mandibular second molars: the mean torque values were
found to be -18.59° with a SD 8.4 and a range of -30 to 31°.
Maxillary first molars: The mean torque values were found to
be -6.65° with a SD 3.39 and a range of -20 to 4°.
Maxillary to mandibular tooth size relationship was
calculated using Bolton's Analysis.
Maxillary second molars: The mean torque values were found
to be -3.6° with a SD 6.65 and a range of -18 to 10°.
The mean anterior ratio was 76.82% with a SD of 4.11
Table 4: Comparison of Maxillary arch parameters between study group and
Andrews Data (Mean ±SD)
International Journal of Contemporary Orthodontics
Table 6: Comparison of Maxillary arch parameters between study group and Currim
and Wadkar Group (Mean ±SD)
4
Vol. 1 Issue 1
.
Patil et al.
and the overall ratio was 90.93% with a SD of 3.63 (Table III).
Discussion
Data from our study was compared mainly with the
data of Andrews's original study but values from other studies
were also compared in relation to our study to give an insight
into the variations and similarities between racial groups.
Positive tip values were obtained for all the maxillary
teeth except the maxillary second molar, however the premolars
were more angulated than Andrews’s sample. Mandibular
incisor, canines and first premolars showed negative
angulation.
The present study showed positive crown inclinations
for maxillary lateral incisors, where as negative crown
inclinations for maxillary central incisors, canines, premolars
and molars. Mandibular incisors showed increased negative
inclination /torque values. Canines, premolars and molars
were less inclined than Andrews sample which showed
higher and progressively increasing negative torque values
from canine to molars.In the mandibular arch, all teeth in our
sample were more upright than those in Andrew’s sample.
The mean Maxillary and Mandibular tooth size ratios,
overall and anterior, were similar to Bolton's ratios showing
mild degree of discrepancy.
Short comings of the present study:

More number of sample size may be included for
accurate results.
Accurately calibrated digital devices may be used to
measure tip, torque and tooth size discrepancies to get
accurate readings.

The values obtained for angulation and inclination in
subjects with Class II division 2 malocclusion are:
Table 8: Comparison of Maxillary and Mandibular arch parameters with Vardimon and
Lambertz Group and Morrow’s Data (Means ±SD)
Angulations of Maxillary teeth: 1.48°± 5.31 for the
central incisors, 7.4° ± 8.85 for lateral incisors, 6.45° ± 8.83
for canines, 5.18° ± 4.97 for first premolars, 5.05° ± 6.23for
second premolars, 4.78° ± 5.04for first molars and -1.89
±7.42 for second molars
Angulations of Mandibular teeth: -0.94° ± 3.97 for
central incisors, -2.33° ± 4.71 for lateral incisors, -2.8° ±
4.98 for canines, -1.7° ± 3.59 for first premolars, 0.93° ±
3.61 for second premolars, 3.13° ± 3.41 for first molar and
6.64° ± 5.49 for second molar.
Inclinations of Maxillary teeth: -10° ± 6.98 for central
incisors, 5.4° ± 8.35 for lateral incisors, -1.57° ± 6.28for
canines, -4.1° ± 4.59 for first premolars, -6.06° ± 4.24 for
second premolars, -6.65° ± 3.39 for first molars and -3.6°
± 6.65 for second molars.
Inclination of Mandibular teeth: central incisors -2.26°
± 6.08 ; lateral incisors -1.98° ± 5.33; canine, -4.48° ± 5.41;
first premolars -6.68° ± 5.41;second premolars -8.68° ± 4.56;
first molars -14.23° ± 5.53; and second molars -18.59° ±
8.4. A low degree of boltan’s discrepancy was found.
Conclusion
The conclusions drawn from the present study are;

Table 7: Comparison of Manidbular arch parameters between Study group and
Currim and Wadkar Group (Mean ±SD)
5


Positive tip values were obtained for all the maxillary
teeth except the maxillary second molar.
Maxillary incisors, canines and molars were less
angulated.
Negative tip values were obtained for mandibular
incisors, canines and first premolars.
International Journal of Contemporary Orthodontics
Patil et al.


Vol. 1 Issue 1
Maxillary incisors were retroclined and maxillary
molars showed reduced inclination.
Mandibular incisors were more upright, where as
canine, premolar and molar are less inclined.
Reference
1. Sangcharearn Y, Ho C. Upper incisor angulation and its
effect
on
molar
relationships.Angle
Orthod.
2007;77:221–225.
2. Delivanis HP, Kuftinec MM. Variation in morphology
of the maxillary central incisors found in class II, division
2 malocclusions. Am J Orthod. 1980;78:438–443.
3. Andrews LF. The six keys to normal occlusion. Am J
Orthod. 1972;62:296–309.
4. Ash MM, Nelson SJ. Wheeler’s Dental Anatomy,
Physiology, and Occlusion. 8th ed. St Louis, Mo:
Saunders; 2003.
5. Bolton WA. Disharmony in tooth size and its relation
to the analysis and treatment of malocclusion. Angle
Orthod.1958;28:13–30.
6. Ho CT, Freer TJ. The graphical analysis of tooth width
discrepancy. Aust Orthod J. 1994;13(2):64–70.
7. Anthanasiou AE. Orthodontic Cephalometry. London,
UK:Mosby-Wolfe; 1995.
8. Williams A, Woodhouse C. The crown to root angle of
maxillary central incisors in different incisal classes. Br J
Orthod.1983;10:159–161.
9. Rudolph DJ, Dominguez PD, Ahn K, Thinh T. The use
of tooth thickness in predicting intermaxillary tooth-size
discrepancies. Angle Orthod. 1998;68:133–138.
10. O’Higgins EA, Kirschen RH, Lee RT. The influence
of maxillary incisor inclination on arch length. Br J
Orthod. 1999;26:97–102.
11. Bennett J, McLaughlin R. Orthodontic Appliance.
London, UK: Mosby-Wolfe;1993.
12. Sondhi A. Anterior interferences: their impact on
anterior inclination and orthodontic finishing procedures.
Semin Orthod. 2003;9:204–215.
13. Sarver D, Sample L. How to avoid surgical failures.
Semin Orthod. 1999; 5: 257-274
International Journal of Contemporary Orthodontics
6