What Is a Dental Arch?

Also known as dentition. The teeth located in the upper and lower jaws are continuously arranged on the alveolar bone to form a parabolic arch.

Chinese name: Dental arch
Foreign name: Dental Arch

Mechanism of action: Human teeth line up
Dental arch shape: Square
Normal human dental arch: Presented as a relatively neat and regular arc

Dental arch overview

Generally divided into three types, namely square, oval and pointed, often consistent with each person's tooth shape and face shape. It has a supporting effect on the soft tissues of the facial and maxillofacial regions, and allows the tongue to move freely. It has important physiological effects on stirring food, swallowing and pronunciation.

An arched dentition lined with teeth in the alveolar is called a dental arch. The upper arch is called the upper dental arch, and the lower arch is called the lower dental arch. Relatively regular upper and lower dental arches are good for biting, cutting, movement and pronunciation.

Dental arch anatomy

Crowded dentition is one of the most common malformations. It means that the position or gap of the teeth on the dental arch is insufficient, and they cannot be arranged in a regular normal arc, but overlap and displace. The mechanism that causes dentition crowding is the imbalance between tooth mass and bone mass, that is, the length of the dental arch (bone mass) is not enough to accommodate all teeth (tooth mass). Among the pathological factors, genetic factors are the most common cause of underdevelopment of the jaw bone, followed by premature loss of deciduous teeth, retention of deciduous teeth, multiple teeth, etc., which causes insufficient gaps in permanent teeth to eruption, which causes crowded and misplaced teeth. Crowding of the anterior teeth is more common than crowding of the posterior teeth, and it is manifested as single or multiple teeth deviating from the arch of the teeth toward the lips and tongue, near and far, or twisting. It disrupts the normal dental arch shape and occlusal relationship, affects chewing function, and hinders oral hygiene and aesthetics. Orthodontic principles can reduce the amount of teeth or increase the amount of bone according to the irregularity of the amount of bone. Decreasing the amount of teeth can be used to reduce the number (extraction) or reduce diameter method; increase bone can be used partial arch, full arch or push the molars to increase the length of the arch backward. Different methods should be selected clinically according to the degree of congestion.

Dental anatomy

Dental arch

Oval dental arch, pointed circular arch, square circular arch.

(1) There is not much difference in the width of each type of dental arch in the posterior segment, but the difference in the anterior segment is large.

(2) The length of the dental arch varies depending on the shape of the dental arch. The pointed round arch is the longest, the square round arch is the shortest, and the oval arch lies in between.

(3) The arches of the teeth of the Chinese are mostly oval and square. It is generally believed that the face shape, tooth shape and dental arch shape are the same. Therefore, attention should be paid to the characteristics of the facial shape when repairing, and the artificial tooth shape corresponding to it should be selected and arranged in a harmonious arch shape.

Dental arch dental arch length

From the contact point of the central incisor, a perpendicular line is formed to the connection of the arch width of the first premolar area, and the length of this perpendicular line is the length of the anterior segment arch. From the contact point of the central incisor, make a vertical line to the line of the width of the arch between the first molars, and the length of this vertical line is the length of the posterior arch.

Dental arch dental arch measurement

The measurement of tooth mass and bone mass on the model is one of the methods of pre-correction diagnosis. Dental arch measurement includes the measurement of crown width, dental arch length, peripheral arch diameter, internal arch peripheral diameter, and peripheral diameter. The measurement of dental arch congestion also includes the measurement of the length and width of the basal bone. As early as 1923, Lundstron proposed that the shape of the dental arch is related to the apical base bone, that is, the shape of the base bone determines the position of the tooth. Any mechanical force cannot make the base bone grow. By the mid-1950s, Howes also suggested that those with normal basal bone development could expand the dental arch. Dental arch measurement can be used for: normal dental arch measurement as the basis for studying the wrong model. The measurement of the wrong dental arch can be used to understand the severity of the deformity. For example, in the case of crowded dentition, by measuring the difference between the amount of teeth and the bone, that is, the gap required to line up the dentition in the arch; For cases of sparse dentition, it can be known that the bone mass is greater than the difference in the amount of teeth, and how much extra space is in the dentition to determine the treatment plan. Measurements after wrong correction. Comparing the model analysis after correction with the measurement data before correction, we can know the changes in the size of the dental arch before and after correction. There are many methods for measuring the arch. The length and width of the arch can be predicted by using the incisors that have emerged, which is convenient for reference before treatment. The tools used for dental arch measurement are double foot gauge, vernier caliper and meter ruler.