Brackets are important components of fixed teeth orthodontic technology, which are directly bonded to the surface of the dental crown with adhesive. The deformed archwire applies various types of orthodontic forces to the teeth through the bracket, thereby moving the teeth and achieving the effect of orthodontic treatment.

Brackets can be classified into metal brackets, ceramic brackets, and composite resin brackets based on their materials. (This type of bracket is rarely used)

According to the application technology, brackets can be roughly classified into: square wire arch brackets, straight wire arch brackets, Begg orthodontic technology brackets, Tip edge orthodontic technology brackets, lingual orthodontic technology brackets, etc. Today, we mainly talk about square wire arch and straight wire arch brackets (the most widely used).

一、Structure of square wire arch bracket:

There is a horizontal groove in the middle of the bracket that accommodates the archwire. The width and depth of the groove can be divided into two types: one is 0.018 inches wide and 0.025 inches deep; The other type is 0.022 inches wide and 0.028 inches deep.

The two types of brackets are referred to as 0.018 brackets and 0.022 brackets, respectively, and are used in conjunction with square archwires of corresponding specifications.

The protrusions at both ends of the bracket are ligature wings, and below the ligature wings are ligature grooves used to fix the archwire, which are used to accommodate ligature wires or ligature rings.

The accuracy of bracket position plays an important role in the entire orthodontic treatment process. Accurate bracket adhesion position can greatly simplify the treatment process, save valuable treatment time, improve treatment efficiency, and shorten the entire orthodontic treatment course.

二、 Key points for bonding square wire arch brackets:

1. The height of the bracket: refers to the vertical distance from the tooth tip or cutting edge to the bracket groove.

2. Axial inclination: For normally arranged teeth, the long axis of the crown has a certain physiological inclination in the near to far range on the tooth surface, so the position of the bracket also needs to consider a certain axial inclination.

3. Near far middle position: The center of the bracket should be aligned with the center of the lip (cheek) surface of the dental crown.

exceptional case:

A: The bracket for twisting teeth is placed on the twisted side of the tongue (the bracket sticks to the side where the teeth are tilted)

B: Tooth extraction case, the bracket is placed on the side close to the gap.

C: The position of the buccal canal is slightly closer to the center.

D: Because everyone's tooth size is different, not everyone's bracket height is fixed, but there is a general ratio, for example, the maxillary canines are 0.5mm higher than the central incisors, and the central incisors are 0.5mm higher than the lateral incisors.

三、 Adhesive position of straight wire arch bracket.

Straight wire arch bracket structure:

1. Gou Gou

0.022 inch x 0.028 inch groove, with preset angles, not all horizontal grooves.

2. Thickness

All data designs included in the brackets are relative to the crown, such as the horizontal angle and thickness of the grooves.

3. Specialized dental use

The preset angle and thickness of the bracket or buccal tube for each tooth of the straight wire arch treatment device are not the same, so they are all specialized for specific teeth (can be mixed in special cases).

Key points for bonding straight wire arch brackets:

(1) Clinical Crown Center.

Clinical dental crown refers to the visible part of teeth with healthy gums exposed in the oral cavity.

The clinical coronal long axis is the line that divides teeth longitudinally into two equal parts, mostly located at the most prominent part of the buccal center of the dental crown. The clinical coronal long axis of molars is the cheek groove between the two large buccal tips.

The intersection of the long axis of the clinical crown and the horizontal line dividing the clinical crown is the center of the clinical crown.

(2) Search for clinical crown centers

Using visual inspection to locate the clinical crown center, align the center point of the bracket groove with the center point of the clinical crown, align the central axis of the bracket with the long axis of the clinical crown, and mark the point on the bracket wing on the far gingival side of the tooth (remember that when the bracket position is correct, the mark point is on the far gingival side)

(3) Why do straight wire arch brackets stick to the clinical crown center of teeth?

If the bracket height is used to determine the position of the bracket, due to the differences in the size and shape of each person's teeth, the adhesive points on each person's dental crown are not fixed.

However, the preset data on the straight wire arch bracket is fixed and cannot be adjusted, which leads to changes in the torque and adduction/abduction settings of the straight wire arch bracket as the bonding position changes, making the straight wire arch bracket very unreliable.

Adhesive bonding of brackets under special circumstances:

*For cases with shallow composite, the upper and lower premolars, the bonding position of brackets, and the clinical crown center closer to the gingival side can reduce the opening and closing of orthodontic treatment in the later stage.

*The position of the front teeth bracket is very important, and inaccurate adhesion can lead to uneven cutting ends of the front teeth. If you are not confident in finding the clinical crown center through visual inspection, you can measure the clinical crown height of the upper central incisor, divide it by 2 to obtain the clinical crown center position of the central incisor, and then use a bracket positioning ruler to locate the position of the central incisor bracket. The bracket height of the lateral incisor is 0.5mm less than that of the central incisor, and the height of the canine teeth is consistent with that of the central incisor. (Approximately 4:3.5:4 or 5:4.5:5 ratio)

*Continuing from the previous point, if the maxillary central incisor (crown) and maxillary lateral incisor (crown) are much larger, the brackets of these two teeth will be stuck at the same height, and after correction, they will look more coordinated. Alternatively, before sticking the brackets, the excessively large and long central incisors may be artificially ground (a small amount of grinding is done in the early stage, and if they are not coordinated in the later stage of orthodontic treatment, the cutting end or bracket position may be adjusted appropriately.

*Inverted brackets 180 ° bonding: lateral incisors with palatal misalignment, individual teeth with reverse alignment, individual lingual misalignment, etc. These types of teeth are prone to crown displacement but root displacement (teeth tilted) during movement.

If the misaligned tooth bracket is inverted 180 ° and bonded, its torque becomes a negative torque in the coronal lingual and root labial directions. When using a square wire arch to move its labial direction, as well as later root control movement, it automatically generates a force that moves the root labial side without the need for additional archwire torque bending.

Disclaimer: The above content is sourced from the internet and is reproduced for sharing purposes only. Any infringement will be deleted.