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The Rational of Orthodontic Treatment

Today we will talk about the rational of orthodontic treatment.Let us start

with the definition, what does orthodontic mean??

Ortho = straight

Dontics = teeth

Orthodontic: is that branch of dentistry that deals with the growth and

development of the face, oral structures and occlusion , and with the

diagnosis ,interception and treatment of occlusal anomalies .

Malocclusion : any features of dental alignment or occlusion at variance

from the ideal.

So anything abnormal with the alignment of the teeth which means that

that teeth are not straight , or not in contact with each other will affect the

occlusion ,like if the upper teeth are ok and the lower teeth are ok and well

aligned but when they occlude together there is a problem.. this is called

"malocclusion".

Plz refer to slide # 3:

You can see this tooth (the upper right canine ) is outside the dental arch so it

is mal-aligned, if you notice the lateral incisor is in cross-bite with the lower

lateral incisor ,( it bites inside the lower lateral incisor)!

What are the indications for orthodontic treatment ?

Why does the orthodontic patient come to your clinic seeking orthodontic

treatment?

1- aesthetics : is the most common cause for orthodontic treatment,

patients come to orthodontists seeking ortho treatment mainly for aesthetic.

Remember you are treating patients not moving teeth !))

So orthodontic treatment can improve:

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- The appearance of the teeth : slide # 6.

- The appearance of the teeth within the face: slide # 7 .

- The appearance of the face: slide # 8 . (this pt. was having class 3 skeletal

malocclusion before treatment)

2 - functional :

(speech , mastication , TMDS)

A-Speech : some of the malocclusion features can affect the development

of speech, however the logical question is: when does the speech start to

develop?

We agree that speech starts to develop at early age ( less than 3 years) so

ortho treatment is not necessarily the treatment.

Studies have shown that ortho treatment can't treat speech problems, but it

can be carried out as adjunctive to speech therapy.

So we should inform the patient that ortho treatments will not necessary

improve the speech, so we should refer him to speech therapist and arrange

the treatment with him.

B-Mastication : (slide # 10) : in this photograph you can see that the

patient has " a big lateral open bite", if you have this malocclusion you will not

be able to masticate, some malocclusion features can affect the efficiency of

mastication, also if the patient has " anterior open bite" between upper and

lower incisors he will not be able to incise, so ortho treatment eliminate these

features can improve the masticatory function.

C- TMDS = Temporo-Mandibular joint Dysfunction Syndrome :

muscles of pain, especially in the chronicor acuteis term covering : Wiki

. The primary temporomandibular jointof the inflammationand/or mastication

, with secondary ismbruxor parafunction, as in the case of -cause is muscular hyper

, like various types of displacement of the musculoskeletal systemeffects on the oral

, which is the painthat can result in significant temporomandibular jointdisc in the

most common TMD symptom, combined with impairment of function. Because the

disorder transcends the boundaries between several health-care disciplines — in

.neurologyand dentistryparticular,

Symptoms:clicking, pain in muscles of mastication,trismus,etc..

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There are many claims (without evidence) regarding this.

It has been claimed that certain malocclusion features are linked to TMDS,

like :

Deep overbite*

Class 3 with large –ve overjet *

Increased overjet*

*AOB(anterior open bite)

*Cross bite

However do these cause TMDS?

"Linked": means- they examined a population of patients & they recorded the

malocclusion features: AOB, increased overjet,crossbite etc…..& they

recorded the signs & symptoms of TMDS if they exist …they found that big

number of patients who have TMDS & its symptoms have increased overjet

for example ,or deep overbite.

Does that mean it's the cause and affects the relationship?! No.

Association doesn’t mean cause .

And why did they take this piece of information eventually?

Because again they examined patients with deep overbite or big overjet but

they don’t have TMDS problems, so if this is the cause why it didn’t cause

TMDS in those patients?

So association does not mean cause, and again treatment of these

features doesn’t mean relation of TMDS.

However; there is one malocclusion feature which has been strongly linked to

"functional, we call it is cross bite with mandibular displacementTMDS which

displacement", do you know what this is?

Imagine the patient bites and there is premature contact on one tooth or two

teeth, do you think the patient will keep biting on those two teeth or the

single tooth? eventually this will cause a trauma, and because of the pain; the

patient will try to get maximum intercuspation by displacing the mandible

either to the right to avoid the premature contact and the interference or to

the left or anteriorly, so the pt. will have displacement.

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If the patient displaces the mandible to the right he will has clear cross bite "

unilateral cross bite".

If the pt. displaces the mandible forward he will has anterior crossbite with

–ve overjet ,ex: "class 3".

So this is the only feature that has been linked to TMDS signs and symptoms.

75% of patients have unilateral cross bite, usually have mandibular

displacement, so you should examine the pt. when you try to manipulate the

mandible to force the pt. biting into " protruded contact position", because

it’s the most reproducible position !.

In this case if the patient has mandibular displacement (because of the

crossbite) the pt. will bite on the premature contact, after that the pt. will go

through dental displacement !! but at least you can make sure that the pt. has

mandibular displacement, in this case you need to treat the pt. as soon as

possible, either to eliminate the TMDS or to prevent the development as

prophylactic.

So functional indication for treatment is when you see a pt. with crossbite and

mandibular displacement even if he doesn't have TMDS (prophylactic).

3- prosthetics : (slide #14) :look at this photograph , this pt. has

congenitally missing lateral incisors , do u think this pt. will accept this big

gaps? (He needs a solution either to fill these gaps with teeth or prosthetic

replacement for this space), however any prosthodontist can't do the

prosthetic replacement.

The prosthodontist will refer the pt. to orthodontist, asking him :

1-can you open the space for me to replace the lateral incisor ?

2-Do you think this pt. will benefit more from closing the space and then I can

reshape the canines to look like the lateral incisors?

So orthodontically either you close or open the space, it depends on many

features , for ex: if the pt. has increased overjet you need to reduce it by

moving the upper teeth back , what do we usually do?

We extract teeth to create space for those teeth to move back, when you

extract premolars to move the central incisors and canines back and open the

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space for the lateral incisors or will you accept those lateral incisors as

extraction space to be used?

In this case you may decide to close just the space and reduce the overjet.

If the pt. has crowding do we use those spaces to align the teeth and relief the

crowding? Or when you extract some teeth and treat them with

prosthodontic replacement which needs long time or extra cost? So it

depends on many features.

On the other hand the pt. may prefer to have the six anterior teeth for big

smile, and when you explain to the pt. the two options of treatment the pt.

may decide that he want the missing teeth to be replaced.. so go ahead and

extract my back teeth.

So the decision should be jointly made between the orthodontist and the pt.

4- prophylactic :

There are many claims (without evidence) that straighter & well aligned teeth

will suffer less from dental caries !!!

a-Dental health

b-trauma

c-teeth attrition , fracture and gingival recession

a- dental health:

Some people think that straighter teeth and aligned teeth will suffer from

less dental carries and periodontal pocket because the patient will be able to

brush his teeth easily.. is this logic? I don’t think so..

The doctor has crowding in his lower teeth and he brushes his teeth and they

are sound; however he seen a lot of pt. with very aligned teeth and have a lot

of restorations and carries

It relates to patient attitudes & his oral hygiene behave.. if the pt. brush his

teeth carefully even though they are crowding.

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What do you think is easier for the pt. to clean the crowding teeth? Or to

clean teeth with fixed appliances?--> crowding teeth.

So if the pt. can't maintain good oral hygiene to crowding teeth .. they for sure

by the end of ortho treatment after two years of fixed appliances they will

have multiple carries teeth.

Development of pathology around teeth especially impacted teeth.

The most common pathology is : cyst..

Cyst inside the bone can get larger and larger and it can affect the roots of the

adjacent teeth.

So in order to prevent such problems we need orthodontic treatment to bring

that impacted teeth into occlusion.

Slide # 19 :

Impacted tooth can cause problem, look at that impacted tooth you can see

dentigerous cyst around it, with time if this cyst gets larger it may reach the

border of the mandible and so any trauma can cause mandibular fractures.

:b-trauma

Teeth most commonly affected for trauma are the upper incisors , prominent

incisors are at high risk of trauma, most common damage for this is the

enamel fracture.

The risk factors for this trauma :

-increased overjet

-prominent upper incisors: 3 times at risk than normal teeth.

-incompetent lips

*competent : means that at least lips are touching each other.

*Overjet > 6 mm increase high risk of trauma.

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c-Attrtition , fracture and gingival recession:

Now if the pt. is biting this way ( the upper lateral biting incisor inside the

lower lateral incisor-the first pic.).. do you think with time it will cause

attrition? Yes, it will

Look at this photograph (slide 21): (a) continuous biting in this way will cause

attrition of the enamel of the upper lateral incisor this way will keep the tooth

move forward causing gingival recession.

(b+c) the same is here attrition of the upper centrals and gingival recession to

the lower centrals.

(d) This deep overbite we can’t see the lower anteriors at all, from inside the

lower anterior biting on the palate will cause gingival recession from inside,

and in some sever cases the upper incisors causing recession for the lower

anteriors.

There is no attrition of the normal teeth because it has normal relationship(

overbite 3-5mm & overjet 3mm) no premature contact.

Benefits & Risks: Any orthodontic treatment to be given should be weighted according to the

risk-benefit equation.

what do you think the benefits the pt. will have by the end of the treatment

and what do you think the risk he will have by the end of the treatment ?! ,

and so you will be able to select your pt. ( selection is very important in

orthodontics

What are the benefits in general? We must weigh the benefits against the

risks before the treatment :

1-aesthetic: orthodontic treatment can close or open spaces to replace teeth

!

2-mastication (it can improve the masticatory function)

3-speech(orthodontic treatment can be carried out as adjunctive to speech

therapy )

4- does it prevent cystic formation or any pathological formation around the

impacted teeth?

5-does it prevent trauma?

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6-does it prevent dental caries or periodontal disease as prophylactic?

Benefits:

improved appearance – better self esteem & self confidence , it will

have psychological effect also..( 60% of children teasted about their

teeth were upset by this).

In theory : well aligned teeth are easier to keep clean-better dental

& periodontal health.

BUT very little evidence that straighter teeth suffer less pathology !!

Risks:

1-dental carries

2-calcification (around the brackets)

3-root resorption : if we apply heavy force root resorption alveolar bone

resorption

4-gingival recession

5-relapse: you may end your treatment with good results but the pt. didn't

wear the retainers after the treatment!

6-medical history: ex: infective endocarditis - any procedure causing bleeding

and bacterial contamination will put the pt. at risk for IE.

Ideal pt. for orthodontic treatment is:

1-pt. with mouth free pathology

2-good oral hygiene

3-cooperative: uncooperative pts.- have not wear the elastics at some stage of

treatment for example) this will affect the duration & the results of the

treatment

4-medically ok..

Forgive us for any mistake

Jumana Othman & hadeel khutaba