T scan and its application in orthodontics

T SCAN AND ITS
APPLICATIONS IN
ORTHODONTICS
PRESENTED BY:
DR. PAYAL OSTWAL
M.D.S III YEAR

Contents
• Introduction
• Conventional occlusal indicators
• Evolution of T scan
• T scan assembly
• Software components
• Benefits, limitations and accuracy of T scan
• Orthodontic applications
• conclusion

Introduction
• Dental occlusion is defined as the static or dynamic
inter-arch relation and corresponds to all possible
contacts established between the opposing teeth.
• The most frequent occlusal position reference is
represented by the maximum
intercuspation that corresponds
to the full and maximal contact
of two arches.

• In 1976, Roth presented the following functional
aspects of the occlusion as being fundamental for
completion of the orthodontic cases:
• 1. Teeth must present maximum intercuspal (MI)
position with the jaw in centric relation (CR).
• 2. In centric relation, all posterior teeth must present
axial occlusal contacts, and the anterior teeth must
maintain a distance of 0.0005 inches between them
Roth RH. The maintenance system and occlusal dynamics. Dent Clin North Am
1976;20:761-788

• 3. During laterotrusion, the canines must disocclude
the posterior teeth (canine guidance).
• 4. During protrusion, the upper anterior teeth must
occlude with the lower anterior teeth and the first
premolar or the second premolar (in extraction
cases), aiming at disoccluding all posterior teeth
(immediate anterior guidance);
• 5. No interference must be present on the balancing
side.

T scan and its application in orthodontics

• The conventional or traditional methods used in
clinical practice for occlusal contact selection during
occlusal adjustment procedures are non–digital.
• Static dental materials are placed between opposing
teeth to imprint, or mark with color, the occlusal
contacts.
• Occlusal adjustments are accomplished using the
appearance characteristics of these nondigital
indicators

• Articulation Paper Strips: That leave
ink marks on the teeth where occlusal
contacts exist.
• Shim-Stock Foils: Which are tugged
and pulled from between the teeth,
to detect withdrawal resistance that
supposedly indicates the presence of
forceful tooth contacts.

• Elastomeric Impression Materials:
Which, when injected between
opposing teeth to locate occlusal
contacts, are displaced completely
where there is tooth contact.
• Occlusal Wax Sheets: Which are
softened and then imprinted by
opposing teeth. Wax perforations
or apparent wax thinness indicate
occlusal contact, or near contact

• None of these static dental materials have
demonstrated the capability to quantify occlusal
forces, to detect occlusal contact time simultaneity,
or determine the sequence of tooth contacts that
occur during a mandibular closure into maximum
intercuspation.
• These static dental materials are indicators of contact
location only and are incapable of quantifying
occlusal force and timing information.
Koos, Bernd & Godt, Arnim & Schille, Christine & Göz, Gernot. (2010). Precision of an Instrumentation-
based Method of Analyzing Occlusion and its Resulting Distribution of Forces in the Dental Arch. Journal of
orofacial orthopedics

• Differences in the intensity of marks may represent
differences in force intensity or could simply reflect
the specific occlusal morphology or the condition of
the occlusal enamel or restoration surface.
• Variations in articulating paper marking may also
arise from differences in paper thickness, the extent
to which it is impregnated with saliva, and the force
of the patient’s bite.
Kerstein RB. Articulating paper mark misconceptions and computerized occlusal analysis
technology. Dent Implantol Update 2008;19(6):41-6.

Solution!!!
• Computerized occlusal analysis is a digital technology
that can record real time relative occlusal force
variance
• T scan records occlusal force and time data from first
contact point into maximum intercuspation and can
identify excursive interference duration that occur
within dynamic occlusal function.

• Computerized occlusal analysis technology evolved in
1984.( Earliest publication by Maness et al. 1987)
Subjectively analysed occlusion
Objective precision measurement
Maness WL, Benjamin M, Podloff R. Computerized occlusal analysis: a new technology. Quintessence Int 1987;
18:292

• Detected relative occlusal force variances can be
employed clinically to precisely balance an unbalanced
occlusion, by using targeted time-based and force-
based occlusal adjustments,

EVOLUTION OF T SCAN
• The T-Scan system was developed as a relative
occlusal force measuring system.
T Scan I
(1984)
T Scan II
(1995)
T Scan III
(2004)
Turbo
(2008)
T Scan 8
(2014)

T SCAN I
• Blue sensor was developed in 1984 that comprised of
an epoxy matrix that encased a pressure sensitive ink
grid formed in the shape of a dental arch

Patyk A, Lotzmann U, Paula JM, Kobes JWR. Ist das T scan eine diagnotisch relevante methode zur
okklusions-kontrolle.ZWR 1989;98;686-94
G1
sensor
foil
Thick,
inflexible &
short shelf life
Inaccurate
readings
G2 sensors were made of urethane which significantly
increased the shelf life and flexibility of sensors although
thickness remained same

T SCAN II 1995
• Redesigned entire hardware compatible with 8 bit
technology that ran under windows architecture.
• Able to record 256 differing levels of occlusal force
compared to 16 level with T scan I.
• G3 sensors with reduced thickness- 1997
• HD sensors-2001

• Garcia G et al 1997
• T scan II reliable method for analysis of occlusal
contact distribution in maximum intercuspation.
Garrido Garcia, V. C., Garcia, C. A. & Gonzalez, S. O. Evaluation of occlusal contacts in maximum
intercuspation using the T-Scan system. J. Oral Rehabil. 24, 899–903 (1997).
• Kerstein 1994
• Disclusion time reduction study
• Measurement capacity of T scan II was highly
reproducible.
Kerstein R. Disclusion time measurement studies: Stability of disclusion time – A 1-year follow-up. J Prosthet Dent
1994;72:164-8

T SCAN III 2004
• USB connection
• Integration with electromyography
system
• Force outliers
• Individual tooth timing

T SCAN III TURBO (2008)
• Recording speed of mandibular movement increased
from 0.01 second to 0.003 second thereby capturing
3 times more occlusal data for analysis.
• Increased ability to locate more non simultaneous
tooth contact sequence and aberrant occlusal force
concentration

ASSEMBLY
• Sensor and a support
• Handle assembly
• System unit
• Computer software
• Printer

Sensor
• The sensor is the key component.
• It is 60 micrometers thick and made of a polyester
film.
• T-Scan sensors are available in two sizes:
1. Large and
2. Small.

Calibration of Sensor
• When patients bite on the sensor, the resultant
change in electric resistance is converted into images
on the screen.
• The program can be operated in two modes:
Time analysis
Force analysis

• Time analysis:
• The location and sequence of occlusal contacts,
showing in a different color the location of the first,
second and third or more contacts .
• On the top of the monitor screen is displayed the
timing of each successive contact with regard to the
first.

• Force analysis:
• This mode offers the operator with data on the
location and relative force of tooth contact. On the
bottom of the screen, bite length can be read.
• Within force analysis, two additional modes can be
selected, instantaneous (which registers mandibular
positions) and sequential (which registers the
intensity of contacts during mandibular movement

• Recording technique:
• For this, the sensor is inserted into the patient's
mouth in such a way as to make its support aligned
centrally with the midline of the upper incisors.
• The patient is then asked to bite on the sensor in a
maximum intercuspation position.
• After the handle button is pressed the arch model is
automatically created on the screen

• A view of the arch upon which the forces exerted are
represented by color histograms ;
• – a familiar occlusal view resembling the picture
given by articulating paper and,
• – two graphs that illustrate the development of
forces over time, as shown below

• The software components of T-Scan are as follows:
• a. Menu bar
• b. Tool bar
• c. Scanning page view side bar
• d. 2D and 3D force view windows
• e. Occlusal time table
• f. Graph
• g. Navigation bar.

• Data interpretation –
• The data recorded is shown as a force film, in which
the center of force trajectory shows the history of
the path of the center of the force from the
beginning of the force movie recording to the current
displayed frame .
• In the occlusal view of contacts, the diamond
represents the center of force and the adjoining
tracing shows its movements during the registration.

• Thus, by gaining information on the earliest occlusal
contact, it can be adjusted and simultaneous occlusal
contact can be established .
• The consequence of this occlusal therapy is that the
patient can feel a more widespread contact sensation
at the end, the reason being that the establishment of
true and measurable bilateral simultaneous occlusal
contacts is achievable using the T Scan.

Dynamic analysis
• An important and useful feature of the T-scan is its
ability to register occlusal contacts during
mandibular excursive movements in real time,
eliminating any need for mounting models on an
articulator.

Benefits
• Improved diagnosis
• Increased quality of care
• Decreased treatment time
• Increased comfort of dental prosthetics
• Reduced risk of implant failure, traumatized teeth,
unstable dentures, ineffective splints, and porcelain
fractures

• Legal documentation of outcome
• Enhanced patient education
• Build your practice
• Increased referral business from other physicians

LIMITATIONS
• Relatively thicker sensors
• May get easily damaged
• Two unlike modes –may mimic different occlusal data

Accuracy of T-scan
• Harvey et al 1992
• Found substantial variability in the results with
unpredictable variation scattered among the uses,
levels of force and articulator immediate side sift
treatments when performing a preliminary test of
reproducibility of a computerized occlusal system.
Harvey WL, Osborne JW, Hatch RA. A preliminary test of the replicability of a
computerized occlusal analysis system. J Prosthet Dent 1992;67(5):697-700.

• Hsu et al 1992
• Sensors did not have the same sensitivity
throughout their surface and the T-scan always
recorded fewer occlusal contacts than were actually
present as checked by occlusal foils.
Hsu M, Palla S, Gallo LM. Sensitivity and reliability of the T-scan system for occlusal
analysis. J Craniomandib Disord 1992;6:17-23.

• Hirano et al 2002
• In vitro study on accuracy and repeatability of the T-
Scan II system reported that T-Scan force recordings
were acceptably precise, especially for the
moderately high level and default level
Hirano S, Okuma K, Hayakawa I. In vitro study on accuracy and repeatability of the T Scan H system Kokubyo
Gakkai Zasshi. 2002 Sep;69(3):194-201.

• Koos B et al 2012
• Tested the accuracy and reliability of an
instrumentation-based method of analysing
occlusion and its resulting distribution of forces in
the dental arch.
• A combination of this method with marking foils
would be ideal because the pressure-sensitive foils in
this system do not produce any contact markings
intraorally.
Koos B, Holler J, Schille C, Godt A. Time-dependent analysis and representation of force distribution and
occlusion contact in the masticatory cycle. Ј Orofac Orthop. 2012 May; 73(3): 204–14.

• Qadeer S et al 2016
• Comparison of closure occlusal force parameters in post-
orthodontic and non-orthodontic subjects using T-Scan®
III
• A significant occlusal force discrepancy was found in the
post-orthodontic subjects, with higher force percentages
observed posteriorly and much less percentage force
anteriorly, when compared to the natural dentition
subjects.
• T scan may be recommended for orthodontic case
finishing.
Sarah Qadeer , Lili Yang , Letrit Sarinnaphakorn & Robert B. Kerstein (2016): Comparison of closure occlusal force
parameters in post-orthodontic and non-orthodontic subjects using T-Scan® III DMD occlusal analysis,
CRANIO®

Orthodontic applications
• It is understood that at the completion of the
orthodontic treatment, there should be
simultaneous contact of all teeth with good timing
and equal intensity of masticatory force distribution
in all mandibular movements.
• All schools of occlusal philosophy state that there
should be canine protected occlusion with anterior
teeth less loaded than the posterior teeth
Cohen-Levy J, Cohen N. Computerized occlusal analysis in Dentofacial orthopedics: indications and clinical use
the T-scan III system. J Dentofacial Anomalies Orthod. 2012;15(2):203–228.

• “What should be the established end
result of occlusal function?”
• 1. Achieving ideal tooth to tooth relation is enough
to obtain measurably balanced occlusion
• 2. After appliance therapy, will the occlusal contacts
spontaneously improve the overall occlusal force
balance from settling?
• 3. Pretreatment dental asymmetry is corrected
orthodontically; will there be posttreatment occlusal
force distribution in a symmetrical fashion?

• Orthodontists are constantly being challenged with
the task of providing their patients with acceptable
esthetics and masticatory function.
• Although esthetics is often the patient’s immediate
and primary goal, function becomes far more
important over the lifetime.
• So developing a sound, functional masticatory
system is the primary goal of all orthodontic therapy.

Temporomandibular disorders (TMD) and
T-scan III
• Temporomandibular disorders is a collective term
used to describe joints, masticatory muscles, and
associated structures, all of which have common
symptoms such as pain and limited mouth opening.
American Association of Oral and Maxillofacial Surgeons (AAOMS). The temporomandibular joint (TMJ).
Retrieved on 10/14/2007

• There exists a relation between complaints of
patients with TMD and static occlusion parameters.
• Dzingute et al
• Values of the centre of the occlusal force distance
and the asymmetry index of occlusal force in TMD
patients with pain in the temporomandibular joint
(TMJ) were significantly higher than in the control
group.
Agnė Dzingutė, Gaivilė Pileičikienė, Aušra Baltrušaitytė, Gediminas Skirbutis. Evaluation of the relationship between the
occlusion parameters and symptoms of the temporomandibular joint disorder. Acta Med Litu. 2017; 24(3): 167–175

• Haralur et al
• Determined the dynamic occlusal parameters using
Tscan III.
• Among the dynamic occlusal parameters evaluated
centric slide and balancing side interferences were
found to be highly influential in TMD etiology. TMD
patients had prolonged disclusion time compared to
healthy TMJ patient
Satheesh B. Haralur, Digital Evaluation of Functional Occlusion Parameters and their Association with
Temperomandibular Disorder. Journal of Clinical and Diagnostic Research. 2013 Aug, Vol-7(8): 1772-1775

Does orthodontic treatment cause TMD??
McNamara, Seligman and Okeson listed eight
conclusions that refute this possible association.
• 1 Signs and symptoms of TMD occur in healthy
individuals
• 2 Signs and symptoms of TMD increase with age,
Thus, TMD that originates during orthodontic
treatment may not be related to the treatment.
• 3 Orthodontic treatment performed during
adolescence generally does not increase or decrease
the chances of developing TMD later in life.
McNamara JA Jr, Seligman DA, Okeson JP. Occlusion, orthodontic treatment, and temporomandibular disorders: a
review. J Orofac Pain. 1995;9:73–90

• 4 The extraction of teeth as part of an orthodontic
treatment plan does not increase the risk of
developing TMD.
• 5 There is no elevated risk for TMD associated with
any particular type of orthodontic mechanics.
• 6 Although a stable occlusion is a reasonable
orthodontic treatment goal, not achieving a specific
gnathologically ideal occlusion does not result in
TMD signs and symptoms.

• 7 No method of TM disorder prevention has been
demonstrated.
•
• 8 When more severe TMD signs and symptoms are
present, simple treatments can alleviate them in
most patients

Orthodontic treatment and TMD
• Headgear and/or class II elastics in correction of
Class II malocclusions with deep interlocking cusps.
Distal pressure on condyle
• HENRICKSON et al
• Patients treated with headgear or class II elastics
didn’t show any signs and symptoms of TMD in the
follow up period of 2 years
Henrikson T, Nilner M. Temporomandibular disorders and the need for stomatognathic treatment in orthodontically treated
and untreated girls. Eur J Orthod. 2000;22:283–292. 82. Rey D, Oberti G, Baccetti T. Evaluation of temporomandib

• Does the removal of teeth as part of an orthodontic
protocol lead to a greater incidence of TMD??
• Sadowsky and Coworkers
• They reported there is no increase in the risk of
development of joint sounds regardless of whether
teeth were removed.
.Sadowsky C, Theisen TA, Sakols EI. Orthodontic treatment and temporomandibular joint sounds –a longitudinal
study. Am J Orthod Dentofacial Orthop. 1991;99:441–447.

• Can orthodontic treatment lead to a posterior
displacement of the mandibular condyle?
• Gianelly et al did the study collecting the tomograms
to evaluate condylar position.
• CT of patients before and after orthodontic
treatment were taken and compared.
• No differences in condylar position were noted
between groups
Gianelly AA. Orthodontics, condylar position, and TMJstatus. Am J Orthod Dentofacial Orthop. 1989;95:521–3.

• Should the occlusion of orthodontic patients be
treated to specific gnathologic standards ?
• Roth et al and Williamson have maintained that
TMDs may result from a failure to treat orthodontic
patients to gnathologic standards that include the
establishment of a “mutually protected occlusion”
and proper seating of the mandibular condyle within
the glenoid fossa

• In summary,
• T-scan III provides a means of discerning anomalies
in the centering and intensity of occlusal forces that
reflect functional asymmetries and muscular spasms.
• However, it is only to be used to supplement, not
substitute for, clinical examinations, and radiographic
imaging.

• Orthodontic treatment may lead to occlusal
discrepancies in the arch due to changing the occlusal
relationships
• Qadeer et al
• Occlusal analysis using T scan III
• Significant occlusal force discrepancy was found in the
post-orthodontic subjects, with higher force percentages
observed posteriorly and much less percentage force
anteriorly, when compared to the natural dentition.
Sarah Qadeer , Lili Yang , Letrit Sarinnaphakorn & Robert B. Kerstein (2016): Comparison of closure occlusal force
parameters in post-orthodontic and non-orthodontic subjects using T-Scan® III DMD occlusal analysis, CRANIO®
Orthodontic End-Result Occlusal Function

• Agbaje et al
• 30 healthy adults with normal occlusion and 40
patients undergoing orthognathic surgery.
• T scan analysis of occlusion in both groups showed
better occlusal force distribution after surgery.
• Thus T scan can be helpful to portray pre and post
operative occlusal contact distribution.

• In Orthodontics, the assessment of occlusal quality has
relied mostly on the visual inspection of occlusal
contacts, by using:
• The intercuspation of stone dental casts.
• Subjectively Interpreting articulating paper marks.
• Listening to oral patient “feel” feedback.

• Neither of these techniques gives the clinician
information about the “timing” of the contacts.
• T scan records occlusal contact force distribution in
real time and also quantifies the time duration of any
frictional occlusal surface engagement.
Occlusal balancing easier

• Besides good esthetics, form and function, achieving
a balanced occlusion is an important goal after
restorative, prosthodontic, or orthodontic treatment.
• Hence, occlusal balancing procedures are of
significant importance after dental treatment, and
many methods are used in clinical practice to
attempt to achieve this occlusal harmony.

Occlusal trauma
• It has been suggested that eccentric occlusal forces
could be a factor in the etiology of abfraction cervical
lesions and that the existence of occlusal micro-
trauma could have a deleterious effect on
periodontal tissues and osseointegrated implants.
• To prevent such undesirable outcomes, occlusal
equilibration has been suggested as the treatment
modality

• Occlusal interferences can induce
• tooth pain,
• mobility,
• masticatory muscle hyperactivity.
• Damaged restorations
• Fractured teeth
• Receding gums or loose teeth
• Pain in the muscles, teeth and jaw joint
• Night time teeth grinding
• Headache and neck pain
• Greater tooth wear and sensitivity

Abfraction
• Associated with bruxism, wear facets, and premature
contacts.
• In the framework of orthodontic treatment, it may
be worthwhile for orthodontists to discern specific
areas of interference and to modify the values of
lateral torque during finishing stages of treatment.
• Furthermore, to guard against bruxism,
orthodontists may use thermoformed splints to
afford mechanical protection to teeth that could be
damaged by unhealthy constraints.

Patient motivation
• T scan offers a great pictorial representation of
patient’s occlusal contacts.
• Easy to motivate patients

Conclusion
• The T-scan III system is a new computerized occlusal
analysis tool that can provide an abundance of
information.
• The T-scan III system offers orthodontists immediate
access to patient’s functional occlusion.
• They can see the static and dynamic quality of inter-
arch contacts in real time in a form that can be
preserved in a record for comparison at any future
date.

T scan and its application in orthodontics

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