Vu Orthodontics - Orthodontist - Braces  & Invisalign

Biomechanics, Philosophy, and Physiology

Among other things, the following are always considered at every office visit:

• biomechanics
• physiologic conditions
• oral hygiene
• periodontal condition
• progress/improvement

The biomechanics employed is continually and carefully evaluated for each patient because patients come with different conditions. 

Our philosophy is to use light forces for physiologic consideration such that teeth move at optimum speed with minimum discomfort to the patient. If discomfort is unavoidable, it would be reduced to the lowest level.  The progression of the arch wires are carefully selected to ensure the patient would experience minimum discomfort.

Some misconception exists regarding the necessary force applied and teeth movement.  Some people thought using heavier force would make teeth move faster.  In fact, the force that is compatible with physiologic condition is very light.  Any heavier force would cause injury to the tissues which then require time for healing.  The treatment time ends up to be longer.  In addition, heavier forcces increase risk of root resorption, cause teeth to tip, and exacerbate periodontal disease. 

Types of Braces 

Braces consist of two components: brackets and archwire. 

Our office provides the following braces for both children and adults:

• conventional metal braces (Fig. 1)
• conventional ceramic braces (Fig. 2)
• self-ligation metal braces (Fig. 3)
• self-ligation ceramic braces (Fig. 4)

Conventional Braces

Conventional braces consist of two types: conventional metal braces and conventional ceramic braces.

Conventional metal braces require elastic ties (or color ties) to tie the archwire to the brackets.  Color ties are often preferred by some children, teenagers, and young adults.  This is an advantage because they can use the color of the "color ties" to coordinate with the colors of their clothes and other jewleries. Some treat their braces like their jewlery.  But the major disadvantage is the elastic ties result in high friction that would impede the function of the braces.  In an effort to reduce the unavoidable friction, some doctors use stainless steel (SS) ligature to tie (ligate) the archwire to the brackets.  But, the end of SS ligature often get undone and cause severe irritation to the patient's cheek or lip or both.  

Fig. 1  Conventional metal braces

 Fig. 2  Conventional ceramic braces

Conventional ceramic braces also require elastic ties to tie the archwire to the brackets.  Some adults prefer ceramic braces to avoid being called "metal mouth."  Naturally, the color of choice for "color ties" is clear.  Unfortunately, this "clear" elastic ties will turn yellow after a color food or drink, causing an unsightly appearance.   

For normal bite or deep bite, ceramic braces should only be placed on the upper arch.  The reason is ceramic is an extremely hard substance, so if ceramic braces are placed in the lower arch, then they will abrade the upper teeth.  For most people, only the upper teeth are shown when they smile, so having the metal braces on the lower teeth is not an esthetic problem.

Conventional ceramic braces have even higher friction than the conventional metal braces because typical archwire is metal, and metal-to-ceramic contact has higher friction than metal-to-metal contact.  Thus, treatment time with conventional ceramic braces are typically longer comparing to conventional metal braces.

Treatment time using conventional braces (metal and ceramic) are longer compared to that using self-ligation braces.

Self-ligation Braces

Unlike conventional metal braces, self-ligation braces are more efficient because of less friction.  Studies have shown that self-ligating brackets significantly lower frictional forces.  Thus, they result in more efficacy in teeth movement; decrease the number of appointments; and shorten treatment time.

For moderate crowding cases, self-ligation braces may reduce the treatment time in about six months (comparing to conventional metal braces).  Since self-ligation braces are with less friction, they are much more efficient than conventional braces.  Self-ligation braces are safe and effective.

Similar to conventional braces, self-ligation braces also consist of two types: self-ligation metal braces and self-ligation ceramic braces. 

Self-ligation Metal Braces: SPEED.  In our practice, at the beginning phase of braces, we employ NiTi Supercable.  This special archwire (uniquely designed by Strite Limited for SPEED braces) exerts the lightest force possible to minimize discomfort that some patients might experience.  If this discomfort is unavoidable, it would be minimized to the lowest level.  After that, the progression of the arch wires will be carefully selected to ensure the patient would experience no pain nor discomfort.   

                Fig. 3  Self-ligation braces: SPEED

Fig.4 Self-ligation ceramic braces: In-Ovation C

Self-ligation Ceramic Braces: In-Ovation® C. This type of ceramic bracket allows doctors to treat patients efficiently and effectively with self-ligation and superb aesthetics.

An alternative to braces: Invisalign

Invisalign (Fig. 5) uses a series of clear aligners that are custom-molded to fit you. The virtually invisible aligners gradually reposition your teeth into a smile you'll be proud of. 

Not everyone is a good candidate for Invisalign.  Some people prefer to call Invisalign as "less-visible braces."  Similar to "clear braces," Invisalign has certain advantages and disadvantages (pro's and con's.)

The following characteristics are unique to Invisalign:

• Remove aligners to eat, brush and floss
• Change aligners every two or three weeks
• Teeth move little-by-little with each aligner
• Regular progress checks with your orthodontist

Fig. 5a  Invisalign: full-face smile

Fig. 5b  Invisalign: smile (showing the aligner)

Fig. 5c  Profile: Invisalign aligner vs. metal braces

Basic types of treatment

• Phase I
• Phase II
• Full

Who needs Phase I?

Phase I is for children (typically around 7-9 years old) with mixed dentition, meaning with mixed "baby" teeth and permanent teeth.  Baby teeth or "milk" teeth are layman terms whereas primary teeth and deciduous teeth are the technical terms. Deciduous is considered a more correct term by many dentists.  Permanent teeth is alsc called adult teeth.

Typical indications for Phase I are

• cross-bites (either anterior or posterior or both)
• crooked front teeth
• upper front teeth stick out
• psychological reason (e.g., for better self esteem, more confidence, etc.)

Phase I may eliminate the need for Phase II or reduce the severity of the dental problem in Phase II (if Phase II becomes necessary).

Treatment time for Phase I is approximatelly 12-18 months which allows the necessary corrections to be made.  If this treatment time becomes longer, patients and parents often get burnt out and discouraged (for a later Phase II).

Who needs Phase II?

Phase II is for children (typically around 12 years old, give and take) who have gone through Phase I previously, and it is best when only one or two deciduous molars remain.  If braces are started at this particular time, advantage of leeway spaces can be utilized such that crowding problem can be resolved easier or without harmful side effects.

There is often a break time between Phase I and Phase II.  How long is the break time?  If Phase I is delayed, then this break time becomes shorter. 

Ideally, the second molars must also be fixed if they are malaligned at the end of Phase II.

The combined treatment time and cost of Phase I and Phase II will certainly exceed those of single-phase treatment, but so will the quality of the results. The reason is the results would be more stable, meaning relapse will less likely to occur.

It is important to inform/educate the patients and their parents the advantages of intercepting growth-and-development problems and avoiding treatment as an adult.

Who needs Full (phase)?

Full (phase) is either for people with all adult teeth or for those with one or two "baby" teeth left so that would be equivalent with combining Phase I and Phase II into a single phase.  The second molars must be fixed if they are malaligned.