Orthodontics

There are many reasons to straighten your teeth. The primary reason for most people is to improve the esthetics, however other reasons include to improve the occlusion and make hygiene easier. The popularity of orthodontics is also increasing, particularly with adults and the use of clear aligners. This is largely due to the improved technology with clear aligners, which is allowing for movements previously not thought possible.

What is Dental Orthodontics?

Orthodontics refers to the purposeful movement of teeth to improve the occlusion, appearance and/or in preparation for restorative dentistry. The classic appearance of orthodontics is the metal brackets attached to the facialThe ‘outside’ surface of the teeth that directly face either the lips or cheeks. surface of teeth with a wire across the front. Newer style of orthodontics involves clear aligners, which are clear molds of plastic that are removable. Most often completed during adolescence, orthodontics is a relatively slow process that can take months to years to fully complete. However in the end, this treatment can really change the appearance, facial structure and smile which is a common insecurity amongst Americans.

What is the Primary Goal of Orthodontics?

The primary goal of all orthodontics can be essentially boiled down to moving a tooth or teeth to a better position. While seemingly simple and straightforward, there is a reason why orthodontics is a specialty as it can get very complicated. The teeth, gums, and jaws must be in harmony to work appropriately in order to last a lifetime. If teeth are occluding non harmoniously, it will lead to many potentially debilitating problems over time. Here are a few goals of orthodontic treatment:

• Correct Malocclusion – As a general rule of thumb, when the teeth are in the correct position they last longer. When teeth are in the natural position they were originally designed to be in, the posterior teeth protect the anterior teeth and vise versa during chewing and tearing. When the teeth are not correctly protecting each other it can lead to excessive wear, fracture, problems in the temporomandibular joint (TMJ) and collapse of the vertical dimension of occlusion (VDO).  
• Improve Esthetics – This is typically the primary reason most people seek orthodontic treatment. Spacing and crowding both can be unaesthetic, so even if the malocclusion isn’t severe, people can still seek orthodontic treatment to reposition teeth in a more aesthetically pleasing fashion. 
• Optimally Position Teeth for Restorative Work – When there is insufficient or excessive space for restorative work such as crowns or implants, teeth need to be repositioned for the best outcome. An instance where this is relevant is when a back tooth is extracted in the past and over time a tooth mesialThe surface of the tooth that is between teeth and is closest to the midline. or distalThe surface of the tooth that is between the teeth and is furthest away from the midline. to the gap have drifted into space of the extracted tooth. In order to replace the extracted tooth, there needs to be enough space to place a prosthetic in which case orthodontics is required to move teeth to gain space.
• Change Facial Features – While a much more uncommon reason for orthodontics, repositioning teeth can change how a face appears. This is most noticeable when looking in the profile view for underdeveloped jaws. By moving some of the teeth around, it is possible to provide more lip support and give a minor ‘facelift’. Although not typically a primary chief complaint, this can be a secondary benefit to orthodontic treatment.

What is the Ideal Occlusion?

The ideal occlusion is a concept of harmonious contact between the teeth of the upper and lower jaw that supports the skeletal structures and joints, protects the teeth during regular excessive use, and is aesthetically pleasing. Due to the variance in humans, there is no cookie cutter occlusion that is ideal for everyone. Instead the aim is to give each individual their own ideal occlusion. While the specifics will vary from provider to provider, here are a few things dentists and orthodontists are looking for:

• Approximately 20% overbite. The maxillary incisors should cover about 20% of the mandibular incisors when biting down.
• Minimal overjet. The maxillary anterior teeth should be just anterior to the mandibular anterior teeth.
• Class I canine relationship. This is defined as the mesial of the maxillary canine coinciding with the distal of the mandibular canine.
• Class I molar relationship. This is defined as the mesiobuccal cusp of the maxillary first molar occluding with the buccalThe same surface as ‘facial’ but technically only on posterior teeth. groove of the mandibular first molar.
• Physiologic rest position. This is the natural position of the jaws that positions the temporomandibular joint in a naturally restful position and eliminates pathologic muscle movements.

Why is the Ideal Occlusion Important?

The ideal occlusion is important because it increases the odds of long term success or in other words, your teeth last longer with pain free joints. When in the ideal position, the teeth are able to not only function properly, but also better protect itself from overuse. Many people unknowingly grind their teeth, a condition known as bruxism. Since teeth are unique bones that do not regeneration, bruxism leads to a multitude of long term problems. They can include:

• Fracturing of teeth
• Excessive wear 
• Collapsed vertical dimension of occlusion (VDO)
• Pain in the TMJ, also known as temporomandibular joint disorder

While these conditions can take many years to manifest symptoms, the definitive solution is extensive and expensive once the symptoms become severe enough. For instance, excessive wear on the teeth wears the teeth down to nubs, collapsing the VDO and requires full mouth reconstruction (FMR) to correct the issue. FMR requires placing crowns on almost all, if not all, of the teeth to reestablish the VDO and realign the jaws.

Additionally when the teeth are in the ideal occlusion, the back and front teeth can protect each other during eating in a term called mutually protected occlusion or canine guidance. Since humans are omnivores, our teeth are shaped with the intent to either bite and tear or grind. The front teeth are used to bite and tear while the back teeth are used to chew up and grind the food into smaller particles. Since the front and back teeth have different purposes, they are shaped differently and during chewing and grinding the front teeth protect the back and the back teeth protect the front at the same time. When teeth are not positioned ideally, they are more prone to fracturing and premature wear.

How Does Orthodontics Work?

Orthodontics works by placing a light but constant pressure on a tooth in a specified direction. The constant pressure signals the osteocytes within the bone to remodel so that bone is simultaneously formed and laid down. This process allows teeth to slowly move through the jawbone over time without pathologic destruction of bone. 

The amount of pressure required to elicit teeth movement is not significant, however it must be constant. An example of tooth movement is from excessive thumb sucking. Although an unwanted displacement, when a child constantly sucks on his or her thumb, the front teeth will procline which leads to an anterior open bite. While the child isn’t putting significant pressure on the teeth while thumb sucking, the constant nature will move the teeth over time.

Additionally a concept of orthodontics is not only to move teeth, but also to keep teeth from moving. Adult teeth in particular will generally move towards the midline or to the opposing arch. This means when a tooth is extracted, the surrounding or opposing teeth typically drift into the open space. This can cause periodontal pocketing and difficulty with hygiene. In order to get the teeth back to where they need to be, a dentist or orthodontist will move the teeth appropriately.

What Are The Advantages Of Orthodontics?

The primary advantage of orthodontics is by moving the tooth itself, the need for more invasive procedures is either reduced or eliminated. For instance, if someone wants to close the gaps between their teeth, orthodontics can easily move the teeth into a better position to improve aesthetics. This leaves the natural tooth structure untouched as opposed to veneers or crowns which often require removal of some tooth. Additionally since there is no synthetic material on the teeth, there will be no need to replace the veneers due to normal wear and tear. 

By placing the teeth in the correct position, the best possible long term outcomes are achieved. While it is possible to fix teeth without the use of orthodontics, the long term oral health will have the best chance of success when orthodontics is used as indicated.

Another important advantage of orthodontics is the improved facial aesthetics, phoneticsThe study of how humans produce and perceive speech. This is affected by the position of teeth, lip tone, space in the mouth amongst other factors., and boost to self-esteem¹Orthodontics: Basic Aspects and Clinical Considerations. Malaligned and crowded teeth are a common source of insecurity and straightening teeth is one aspect to achieving a state of complete physical, mental, and social well being.

What Are The Disadvantages Of Orthodontics?

A big disadvantage of orthodontics is the time required to achieve the desired results. If teeth are moved too quickly, complications²https://europepmc.org/article/med/1298455 are more likely to occur. Thus teeth are moved slowly to have a higher chance of no complications. This often means that orthodontics can take anywhere from a few months up to years to complete treatment. 

Other disadvantages include difficulty with hygiene which is exacerbated with metal brackets as well as compliance with the aligner trays. Clear aligners work well, but sometimes wearing them as prescribed can be difficult for patients and if full compliance isn’t done, it can lead to an unpredictable treatment timeline.

As with any treatment there are also risks to orthodontic treatment. These risks include:

• Damage to the teeth and supporting tissues
• Root resorption
• Tooth discoloration
• Periodontal complications such as recession
• PulpThe nerve tissue of the tooth. damage
• Allergic reactions
• Craniomandibular dysfunction
• Increased difficulty with hygiene, leading to increased risk of caries

Change in facial structure may also occur although this can also be seen as an advantage. Teeth and the supporting jaws help shape the appearance of the face. For example, if the maxillary anterior teeth are severely proclined, it may give off the appearance of buck teeth or lips that are too full. By reclining the teeth, this can be corrected. On the other hand, the opposite is true where the teeth can make the lips and face appear different which may not always be a welcomed change.

What’s the Difference Between Clear Aligners (Invisalign) and Metal Braces?

Orthodontics uses techniques and instruments that will move teeth in a specific direction whether that be rotation, tipping, procline, or intruding to name a few. The two most common methods to complete orthodontic movements are clear aligners and brackets. It should be noted that clear aligners are commonly known as Invisalign, however Invisalign is the specific brand and clear aligners refers to the methodology, similar to how Kleenex is a brand of facial tissues. Brackets can be either metal or porcelain, however metal is much more commonly used.

The biggest difference between the two methods is a push vs pull type movement. Clear aligners push teeth while metal braces pull. Imagine someone trying to move a box from point A to B: that person can either stand behind the box and push or stand in front of the box and pull. In the end the box is still moved from A to B, but the methodology was different. 

Brackets (Metal or Porcelain Braces)

This is what is traditionally known and seen with orthodontic treatment. This style uses metal or porcelain brackets that are attached to the facial or lingual side of the teeth, although metal brackets on the facial surfaces is by and far the most common. There is a metal wire that is attached to the brackets and the wire is bent in a specific manner to guide tooth movement. It is in this way that metal braces move teeth by gently pulling teeth into alignment. 

Advantages of Metal Braces

One of the biggest reasons to use brackets and wire is that there are some movements that are easier or only possible with brackets. One of these movements is extrusion or pulling a tooth out of the gums into the mouth. This is required when a tooth needs help fully erupting or has erupted severely away from where it should have. For example, a canine can erupt extremely apically or be impacted with the closest access to the palate. When this occurs, a bracket is required to be able to pull the tooth into place. Imagine a rock embedded in concrete with only a small area of rock visible. There is no way to push the rock out, but you can attach an anchor to the rock and pull it out.

Another advantage of metal braces is there is no compliance that is required. Since they cannot be removed by the patient, there is no need to worry about keeping track, losing, or wearing the brackets and wire.

Disadvantages of Metal Braces

One of the biggest disadvantages of brackets is the difficulty required for proper hygiene. It is incredibly important that during orthodontic treatment the teeth are maintained in a disease free state. Since the wire and brackets cannot be easily removed, the patient is then required to spend a significantly increased amount of time for proper hygiene. Flossing in particular can be very time consuming, since the floss will need to be threaded between each tooth. Other disadvantages include poor aesthetics and trauma to the soft tissues. Many view metal brackets as ugly and there is a general stigma around getting metal braces as an adult. Additionally those who participate in sports, especially contact sports, are at a much higher risk of lacerated soft tissue. 

Clear Aligners

Commonly known as “Invisalign” due to the company’s marketing efforts, clear aligners refer to the clear trays that are switched out every week or two over the course of treatment. This style of orthodontics has gained immense popularity partly due to increased technology, in particular 3D printing technology. As previously mentioned, this style of orthodontics is the push movement that uses clear plastic to move the teeth into the desired location. Very often attachments, or compositeA synthetic resin that is used for while fillings. This is what most people receive when they get fillings. material in various shapes and forms, are bonded to the facial surface in order to better move the teeth. As the technology advances and acceptance of this style of orthodontics grows, it has the potential to outpace traditional wire and brackets orthodontics.

Advantages of Clear Aligners

The biggest advantages of clear aligners are the improved esthetics and hygienic ability. Historically metal braces, especially for adults, have been seen as unattractive and unaesthetic. This can be a deterrent for those who would otherwise want straight teeth. Although not invisible, clear aligners are not as visually intrusive as metal brackets are. Another big advantage is the ease of hygiene since the trays can be removed. Since they can be removed, the teeth can be easily cleaned as the attachments do not get in the way. 

Another advantage of clear aligners is the ability to simultaneously move multiple teeth. Different teeth can be pushed on at the same time, potentially resulting in a shorter treatment time as opposed to wire and bracket orthodontics.

Disadvantages of Clear Aligners

While there are many advantages, clear aligners are not without disadvantages. The primary one is compliance. How adherent someone is to wearing the aligners as prescribed will dictate the timely success of treatment. Clear aligners are supposed to be worn 22 hours a day – they are only supposed to be removed to eat and for oral hygiene. If someone doesn’t wear them as directed, the teeth will not move as scheduled. This can pose a problem with an age group that regularly receives orthodontic treatment: teenagers. Known to be more rebellious than other age groups, ensuring compliance with clear aligners is going to be key to its success.

Other disadvantages include the inability or difficulty in performing certain movements. While clear aligners are extremely effective and able to do a vast majority of the same movements as metal braces, there are a few movements that are impossible. One such movement is moving an impacted canine into occlusion. From time to time, canine teeth are partially or completely encased in bone, and not even visible from inside the mouth. When this happens, the canine must be exposed and have a traditional wire bracket placed and pulled into place. Clear aligners cannot complete this movement along with a few others.

Why Does Orthodontic Treatment Take So Long

Orthodontic treatment is typically measured by months and not days or weeks. The reason ortho takes a long time is due to the time required by the osteocytes to remove and deposit bone within the jaw. This process does take time, as opposed to many other dental treatments. If teeth are moved too quickly, complications are more likely to occur. If you are planning to undergo orthodontic treatment, expect for the treatment to take at least a few months.