Ortodonzia

PROPORTIONS

In recent years, many adult patients seek for orthodontic treatment to improve their smile or facial aesthetic.

Sometimes a simple teeth straightening can be enough, other times a maxillofacial surgeon is required to improve

the patient’s case.

While dealing with adults we should understand if the patient only searches for a straightening of teeth or for a

modification in their face proportions, the latter obtained mostly through surgical procedures.

We should also learn how to see properly a face.

Of course beauty is subjective, but we should learn what to look for and why we like a face or not.

We need a sort of educational beauty training both from a frontal and from a profile side.

The most important features regarding face beauty are averageness, sexual dysmorphism, youthfulness & symmetry.

The ideal proportions are related to the golden ratio number (1,618) that expresses harmony and symmetry.

In art and also nature we can see this number reproduce over and over.

However proportion does not necessarily define beauty, and features out of this make a face more attractive.

So, modern orthodontic treatment goals are :

Improve facial and smile appearance. Malocclusion is a disease only if the patient sees it like that.

→ Establish a normal oral function and performance allowing physiological adaptation.

→ Obtain an optimal occlusion proper for our patient.

→ Achieve stability of dentition expecting the physiological rebound, since our goal is to maintain the results

→ throughthrugh life. 3 AZ

ORTHODIAGNOSIS

The first step of a proper orthodiagnosis is the collection of all the infos we need. This means that we should proceed

with a medical and dental anamnesis for both young and adult patients.

Then we proceed with the clinical examination, that includes both extraoral and intraoral examination.

This step actually comprehends orthodontic records, models, pictures and radiographs.

Among the essential records we have model casts, pantograph, OPT and cephalogram.

MEDICAL AND DENTAL HISTORY

This step can be approached with a written form to give to the patient/parents, that they fill while waiting and we

should then check, or by filling it ourselves through an interview.

A. PATIENT COMPLAIN : major reason for seeking orthodontic treatment. It can either come from the patient or

from the parents.

› The main reasons are :

i. Impaired dentofacial aesthetics causing psychosocial problems → malocclusion per se is not

a disease, it can be if it causes psychosocial problems or facial disharmony.

ii. Functional problems → usually speech or TMJ problems. This problems can only slightly be

treated by orthodontics, the usually require a TMJ specialist intervention.

iii. Enhance dentofacial aesthetics → a good facial aesthetic is much important in our society,

leading to a better social quality of life.

› The form should also include patient name, telephone and various infos.

› Should we not use a paper form, we can still put all the information in our software.

B. MEDICAL HISTORY : we should know about medical conditions that could affect the orthodontic treatment.

i. Allergies → allergy to metals, acrylics or nickel should be taken into account.

We should always prove that the allergy is real, and if so we should search substitute materials.

ii. Asthma → these patients are more prone to root resorption, and require monitoring each

6 months. Heavy orthodontic forces could trigger this situation.

iii. Coagulation disorders → treatment causing bleeding should be avoided.

iv. Diabetes → these patient are more prone to periodontal disease, so sometimes we should

need the aid of a periodontist.

v. Epilepsy → the medications used to treat epilepsy lead to gingival hypertrophy. These patients

require a careful plaque control and sometimes also surgical intervention.

vi. Heart valve conditions → being more susceptible for infections, these patients require

premedication with antibiotics before invasive procedures.

vii. High blood pressure → the medications used to treat the condition also cause gingival

hyperplasia. Again these patients require careful plaque control.

viii. Osteoporosis → these patients take bisphosphonates to improve their condition, and in

orthodontic treatment these medications could lead to tooth movement and osteonecrosis.

ix. Muscle hyperactivity / hypoactivity → patients with mental or physical handicaps can also

have muscular problems. We should always evaluate if is worth to start the orthodontic

treatment since there is a higher probability of relapse and other dental complications.

x. Rheumatoid arthritis / psoriatic arthritis → this condition can lead to TMJ degeneration and

condyle flattening, sometimes causing facial asymmetry.

› Sometimes it can include questions about the diet. A well balanced diet helps to better

understand pathologies like caries.

C. DENTAL HISTORY : this part of the form should include both data from the past and the present.

i. Timing of dentition → if the patient had an early deciduous dentition he’ll have also an early

permanent dentition, and the same is for a late dentition.

We should carefully consider time to find the appropriate time to start the treatment.

ii. Dental anomalies → supernumerary teeth, congenital abnormalities…

iii. Fillings, caries, restorations.

iv. Traumas, fractures, infections.

v. Difficulty breathing.

vi. Bad habits → thumb sucking, tongue trusting, mouth breathing.

vii. Speech problem → usually mentioned early in the visit.

viii. Tooth grinding / clenching → in youngs is usually due to muscle stress so not important.

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D. GROWTH AND DEVELOPMENT

i. Physical growth evaluation → we should carefully evaluate growth and development of the

patient to properly time orthodontic treatment.

ii. Jaws growth → in particular stages of growth we can modify the growth of the jaws through

specific treatments. We can identify the pubertal peak through biological signs or

cephalogram, or even by the parents information.

iii. Pubertal spurt → this is independent from the age, since girls have an early pubertal spurt (10-

11 years) while boys have a late pubertal spurt (15-16 years).

CLINICAL EXAMINATION

The first visit should take more time than the others, since we want to give to the parents and the patient a sense of

professionality and a good impression.

We should prepare the basis for the following analysis and get a clear idea of the case.

EXTRAORAL EXAMINATION allows us to evaluate proportions since symmetry and proportions increase the

attractiveness. Since our treatment in growing patients can alter their facial appearance we should understand

properly facial aesthetics.

FRONTAL FACIAL ANALYSIS

→ Symmetry

 Minor asymmetries exist in all patients, so no

 one is perfectly symmetric.

Taking a picture eases the analysis of

 symmetry, and we can do it by dividing the

face in 5 areas.

The pa r-ex r is the first line traced

— in the postaurale (pa) R point,

which is the most posterior point

on the helix.

The ex r-en r is the line traced in

— the exocanthion (ex) R point, that

is the lateral point of palpebral

fissure at outer canthus of the eye.

The en r-en r is the line traced in

— the endocanthion (en) R point,

which is the medial point of

palpebral fissure at inner canthus of the eye.

All these lines are repeated on the other side of the face, and are called en l-en l ,

— ex l-en l and pa l-ex l .

We can also trace the midline that passes in cupid’s bow

— and glabella ( ) to better help us

most protruded forehead point

assess the asymmetries.

The girl on the right presents a clear vertical discrepancy in the eyes

 and a little deviation of the chin on the right.

We can’t solve the discrepancy of the eyes, but we know that

sometimes this asymmetry is also present in the occlusion. This

means that we should carefully search for this kind of skeletal

asymmetries.

To check for orbital symmetry we should instead make the

 interpupillary line that should be parallel to the floor and the

occlusal plane.

If we want to look for proportion, each fifth should be the same width of an eye.

 Also the mouth width should be equal to the distance between the medial margins of eyes.

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Lips

 We should analyse the patient lips both in rest position and slightly touching.

 If the patient can’t close its lips without straining the periorbital muscles we can say that the

 patient has incompetent lips. This can be due to short upper lip or too high vertical dimension.

Other patients instead can display a gummy smile that could be due to short incisors or a

 passive eruption of gingiva. However a gummy smile is largely acceptable in young patients.

Buccal corridors

 We aim to avoid buccal corridors at the end of the treatment.

 It can be either due to a narrow maxilla, due to a palatine

 inclined maxillary posterior teeth or a combination of both.

Smile line

 The curve of the smile line should be touching the lower lip.

 There is no specific rule valid for each patient.

 We want always to prevent a flat smile line or reverse smile line,

 because these are considered unattractive.

Smile symmetry

 We should see the same size and shape of teeth on

 both sides.

The relation of intraoral tissue to lips should be the

 same.

We should notice if there is an inclination in maxillary

 skeletal base.

Important mention should be given to different

 amount of tooth eruption on both sides.

Dental midline

 A discrepancy of less than 2mm between upper dental midline and facial midline is not

 perceived.

An unparallel incisor relation could be due to an open bite on one side or even to an oblique

 inclination of the incisors.

If upper and lower dental midline are aligned but off from facial midline, it is not evident up to

 2mm. This can also be simply treated with an extraction to move the midline.

.

PROFILE FACIAL ANALYSIS

→ Lips

 On a profile view we can modify lip appearance thanks to incisor inclination.

 Special attention should be given to lip posture and tonicity. Lips at rest form the normal

 interlabial gap range around 1 – 3 mm.

If patient strains too much the perioral muscle it means we have too much gap.

We then should consider the anteroposterior position of the lips with a context for each

 patient. We know that lips position differs much based on age (loss of tonicity) and race.

Soft tissue profile analysis

 To assess if the lips are too anterior or too

 posterior we can use different aesthetic

lines.

E-line : nasal tip to soft tissue pogonium.

o The upper lip should be 4mm behind and

the lower lip 2mm behind.

This is highly dependant on nasal and chin

dimension