上海·雅嘉齿科

Crown | Orthodontic Treatment | Root Canal Treatment

Crown

A crown refers to the placement of an artificial crown on a tooth. It acts as a 'cap' that fits over the tooth which has been previously shaped and contoured.

Purpose
(1) To restore the original shape and function of teeth.
(2) To improve the aesthetics of teeth, such as shape, size and colour.
(3) To fix a bridge onto the teeth — a fixed bridge is supported by crowns on either / both side.

Materials

(1) Porcelain

Properties:

Aesthetic — the colour and translucency can match the natural teeth

The material is not easily stained

Hard and high in wear resistance

Disadvantage

More expensive than other materials

Application

Tooth veneer or crown

To restore teeth with high aesthetic requirement, especially the front teeth and lower back teeth

(2) Gold alloy

Properties:

Durable

High wear resistance

Gold alloy crown can be quite thin — only a small amount of tooth substance needs to be removed to accommodate it.

Disadvantage

Metallic colour, poor aesthetics.

Application

Used at high stress bearing area where good aesthetics is not a must. For example, back teeth.

(3) Porcelain fused to gold
Properties

Aesthetic — colour of outer surface is similar to natural tooth.

Strong and durable because of the gold alloy base.

Hard.

Disadvantage

More tooth substance needs to be removed from the facial surface of the tooth.

Application

Used on front teeth and back teeth

(4) Stainless steel
Properties

Stainless steel crown is not custom-made. It is preformed with several sizes.

Since the crown is not custom-made, the procedures of fitting are simple and the time taken is relatively short.

Disadvantage

Silvery colour, unaesthetic

Non-stress bearing, not lasting

Since the crown margin is not closely adapted to the tooth, the margin is prone to accumulation of dental plaque which causes dental caries and periodontal disease

Application

Used on molars of deciduous teeth

Orthodontic Treatment

Orthodontic treatment is a series of processes that move the teeth to the desired positions in the mouth by orthodontic appliances.

Orthodontic treatment is a complex dental treatment. Before commencing an orthodontic treatment, you should consult an orthodontist to understand your oral condition and the details of the treatment involved.

A. Purpose

To improve aesthetics.

To improve the occlusion between the upper and lower teeth in order to improve the masticatory function.

To improve the alignment of teeth so that a well-support denture / bridge can be fitted.

B. Types of orthodontic appliances

1. Fixed orthodontic appliance

Materials and mechanism

Orthodontic brackets are attached to the tooth surfaces in appropriate positions so that when the orthodontic brackets and orthodontic wire are tied up, the spring back action of the orthodontic wire will move the teeth.

Gradually, the teeth are moved to the desired positions determined by the shape of the orthodontic wire.

Procedures for fixed orthodontic appliance

Placement of orthodontic brackets.

The orthodontic wire and orthodontic brackets are connected by elastics and stainless steel wire (ligatures).

Regular dental visit should be made according to the instruction of the orthodontist to:

Check the movement of the teeth

Change the elastics or stainless steel wire

Change the orthodontic wire

After the teeth have moved to the desired positions, a retainer is inserted to hold and stabilize the tooth positions.

Treatment duration
Overall treatment duration lasts for about one and a half to three years. The actual time needed depends on the complexity of treatment.

2. Removable orthodontic appliance

Materials and mechanism Springs or screws are embedded in an acrylic plate, which is held in place by clasps, to move the teeth to their desired positions. Procedures for removable orthodontic appliance

Impressions of the teeth are taken.

The removable orthodontic appliance is fabricated in the dental laboratory.

Adjust the springs and screws and let the patient try on the appliance.

Regular dental visits to check the tooth movements and adjust the springs.

After the teeth have moved to the desired positions, the removable orthodontic appliance will serve as a retainer to stabilize the tooth positions.

Treatment duration
The overall duration lasts for about 12 to 18 months. The actual time needed depends on the complexity of treatment.

C. Points to note on orthodontic treatments

If you are wearing orthodontic appliances, you should pay extra attention towards oral hygiene to prevent dental caries and periodontal disease.

If you are wearing a removable orthodontic appliance, the appliance and teeth must be thoroughly cleaned every morning and evening before wearing it again. Leave the appliance in plain water when it is not worn.

If severe discomfort is felt when wearing orthodontic appliances, consult your orthodontist immediately.

Root Canal Treatment

What is root canal treatment?

The procedure involves removing inflamed or damaged tissue from inside a tooth and cleaning, filling and sealing the remaining space.

The pulp, or soft inner tissue of your tooth, is normally surrounded and protected by a layer of dentin. Above the gumline, the dentin is protected by a layer of enamel; below the gumline, the dentin is covered by cementum. When a deep cavity, decay or crack destroys these protective layers, the pulp is exposed to the bacteria in your mouth. This can result in infection inflammation, and, eventually, necrosis (pulp death). A severe blow to the tooth can also damage the pulp. Irritants may

then escape from the end of the root and cause a diseased area (apical lesion) in the bone.
Root canal treatment removes the damaged pulp and irritants. This allows the bone surrounding the root end to repair and heal.

Couldn’t I just have the tooth removed?

You could, but then adjoining teeth may shift and interfere with biting and chewing. You can have a replacement tooth implanted or attached to adjacent healthy teeth, but this can be expensive and require even more dental treatment. There is no real substitute for your own tooth, which is more efficient in chewing and biting than an artificial one would be.

What happens during root canal treatment?

An examination, including X-ray, will be performed. A local anesthetic will be given if necessary. Complete tratment consists of the following five basic steps:

Step 1. An opening is made in the crown of the tooth.
Step 2. The pulp is removed from the pulp chamber and root canals. Tiny instruments are used to clean the root canals and shape them to a form that will ensure they will be well sealed. A temporary filling is placed in the opening to seal the opening and protect the tooth between visits.
Step 3. The root canals are filled and sealed with a material that prevents bacteria from re-entering. The opening in the crown of the tooth is sealed with a temporary filling. Radiographs (x-rays) are made before, during and after treatment.
Step 4. At future appointments, the temporary filling will be replaced with a permanent filling and/or crown.
Step 5. The root canal, permanent filling, and/or crown are evaluated for healing at periodic intervals called recall appointments. Remember, if your tooth hurt before you came in for treatment, it may take a while to heal.

Is this going to hurt?
With modern techniques and anesthetics people report that having a root canal treatment is about as unremarkable as having a cavity filled. Should you experience any discomfort, signal your dentist, who will do everything possible to make you comfortable.

During a Root Canal Treament

Soreness
Most patients experience a little soreness after the appointment.

This may be due to the injection, the necessity of keeping the mouth open for a long time, or the treatment. Your temporary filling will be hard enough to bite on within approximately a half-hour, but avoid biting or chewing on the treated tooth if it hurts.

Pain
Over-the-counter analgesics like acetaminophen, aspirin or ibuprofen usually relieve the discomfort. Should pain last more than a few days, or if severe pain or swelling occur, call your treating department.