① Use various orthodontic methods to increase bone mass or/and reduce tooth mass, so that tooth mass and bone mass tend to be coordinated, while taking into account the coordination, stability and facial beauty of the teeth, jaws and face.

② Methods to increase bone mass include expanding the length and width of the dental arch, such as stimulating the growth of the jaw and alveolar bone through functional appliances, extending the growth of the alveolar bone through surgical methods such as distraction osteogenesis, and increasing the length and width of the dental arch. The midpalatal suture extends the width of the maxilla, etc.

③ Methods to reduce the number of teeth include reducing the number of teeth through tooth extraction or reducing the mesial and distal width of the teeth through proximal diameter reduction.

① The mechanism of uneven tooth and bone mass: It may be simply that the tooth mass is too large, or the bone mass is simply too small, or both may exist at the same time.

② Severity of dental crowding: The more severe the dental crowding, the more likely it is that teeth will be extracted and corrected.

③ Combined types of malocclusion: For the same amount of dental crowding, different treatment plans may be required for different types of malocclusion. For example, if the maxillary anterior teeth are also crowded, subtractive treatment may be required for Angle Class I malocclusion, while for Angle Class II malocclusion, labial treatment of the maxillary anterior teeth is often used, combined with the maxillary and mandibular and dental treatment. The adjustment of the arch relationship establishes the normal sagittal relationship between the maxillary and mandibular dental arches.

④ Dental health: If there are extra teeth, severely deformed teeth, or severely decayed teeth, consider extracting the above teeth first.

⑤ Maxillofacial growth and development status: Conventional rapid arch expansion and jaw growth stimulation methods are suitable for implementation during the growth and development stage.

Including dental arch length expansion and width expansion, it is the main measure to increase bone mass. The expansion of the dental arch length mainly includes pushing the molars distally and moving the incisors labially. Dental arch width expansion mainly includes midpalatal suture expansion, orthodontic arch expansion and dental arch-alveolar bone functional expansion.

Arch length expansion

There are three ways to expand the dental arch width: orthopedic expansion, orthodontic expansion and functional expansion

orthopedic expansion

Orthodontic expansion:

Functional expansion:

. For mild crowding, dental arch expansion or interproximal diameter reduction is used. For severe crowding, tooth extraction is used. For moderate crowding, most cases are marginal cases where teeth may or may not be extracted. At this time, the patient's dentofacial hard and soft tissue morphology should be considered. , and then decide on the treatment plan after comprehensive measurement and analysis.

① Discovering and removing the cause of the disease is conducive to completing the correction of dental space efficiently and is also conducive to maintaining the results of correction.

② Whether to choose gap closure or centralized gap repair in orthodontic design requires consideration of many factors, such as the reason for the formation of the gap, the location and amount of the gap, the morphology of the patient's dentofacial hard and soft tissues and their relationship, and combined with the patient's main complaint.

(1) Dental space caused by abnormal labial frenulum It needs to be combined with frenulum trimming, removal of thick interdental fibrous tissue, and supracrestal ligament circumcision or interpeak ligament severing. It is common for the fibrous tissue of the upper lip frenulum to become thick and excessively embedded between the incisors, resulting in gaps in the central incisors. The formation of scar after surgery will hinder the closure of the space. If the gap between the central incisors is small, it is recommended to perform frenulum revision surgery after closing the space; If the gap is large, it is recommended to perform orthodontic treatment to close part of the gap, then perform frenulum revision surgery, and close the remaining gap immediately after surgery.

(2) For dentition gaps caused by excessive tongue body, partial tongue resection can be considered if necessary, otherwise it will need to be maintained permanently.

(3) For local gaps caused by impacted teeth, traction or extraction of the impacted teeth must be performed as appropriate.

(4) Get rid of bad oral habits such as thumb-sucking, tongue-sucking, and lip-biting habits, and guide patients to make corrections on their own. If necessary, use appliances to eliminate bad habits.

(5) Scattered teeth caused by periodontal disease require periodontal treatment first. When the periodontal disease is stable, orthodontic treatment can be performed and the gaps can be closed. Regular periodontal maintenance is required during the orthodontic treatment process.

(6) For gaps between the front teeth caused by bad pronunciation habits, patients should undergo pronunciation training and tongue muscle training, and if necessary, use orthodontic devices such as palatal spines to correct them.

① The interactive anchorage method can be used to close the space between the central incisors. The spring closing method between the brackets, the segmented arch plus rubber band traction sliding closing method, etc. can be used. It should be noted that you must not simply put a rubber band directly on the central incisor with a gap to close the gap. Otherwise, the rubber band will slide along the crown to the root tip, causing periodontal tissue lesions and causing the tooth to loosen and fall out.

② For patients who have a space between their teeth and need to shorten their dental arch, they can use the double-curved labial arch of a removable appliance to retract the front teeth to close the space, or they can use a fixed appliance to close the space by closing the curve or sliding method. When adducting the front teeth to close the gap, attention should be paid to the control of overbite. If necessary, the front teeth need to be depressed or the back teeth raised to open the bite. At the same time, attention should be paid to the control of the torque of the front teeth.

① For scattered gaps caused by abnormally small teeth, such as tapered maxillary lateral incisors, fixed appliances can be used to concentrate the gaps in the mesial and distal areas of the modified teeth, and crowns can be used to restore the teeth to their normal shape, which is beneficial to aesthetics and the stability of the occlusal relationship.

② People with congenitally missing teeth or acquired teeth that are not repaired in time are often prone to problems such as tilting and shifting of adjacent teeth and elongation of opposing teeth. Fixed appliances can be used to straighten the adjacent teeth and lower the elongated opposing teeth. , concentrated space for denture repair

①【Indications】General correction is usually used for bimaxillary protrusion that does not exist or only has mild or moderate skeletal factors.

② [Treatment Purpose] The main goal of orthodontic treatment is to reduce the protrusion of the maxillary and mandibular anterior teeth, thereby reducing the lip protrusion and improving the profile appearance and lip closing function.

③[Treatment Plan] Since improving protrusion often requires more retraction of the maxillary and mandibular front teeth, which requires a large amount of space, tooth extraction is often used. Most of the time, 4 first premolars are extracted, and a thick stainless steel square wire is used as a working wire to retract the anterior teeth and close the gap.

④ If the degree of bimaxillary protrusion is mild, the extraction of the second premolar should be considered without additional anchorage to avoid excessive adduction of the anterior teeth;

⑤ For those who refuse to extract the premolars, on the premise that there is alveolar bone distal to the second molars, you can also choose to extract the 4 third molars, and use implants as anchorage to distally move the upper and lower dentition as a whole to achieve adduction. The purpose of reducing anterior teeth and labial protrusion.

⑥ [Possible impact] Orthodontic treatment for bimaxillary protrusion usually takes a long time, and the incisor roots are more likely to be resorbed, and the degree may be severe; in addition, large adduction of the front teeth may cause the tongue to move backward, so close attention is required Airway changes.

① For bimaxillary protrusion with severe skeletal factors, combined orthodontic-orthognathic treatment is required, and surgical retraction of the jaw or alveolar bone is required.

② When establishing the correction goals for bimaxillary protrusion, the patient's racial characteristics and individual aesthetics should be fully considered. There is no absolutely universal profile standard.

③ The growth and development rules of the craniofacial region should also be considered. The general trend is that with age, the forehead gradually becomes protruding, the front teeth gradually become upright, and the lips move backward.

④ For younger patients with bimaxillary protrusion, do not pursue excessive retraction of the front teeth to avoid causing the lips to appear too retracted relative to their actual age.

Anterior crossbite can include individual anterior crossbites or multiple anterior crossbites. Most anterior crossbites refer to the cross-occlusion relationship between more than three maxillary anterior teeth and the opposing teeth, which is a type of malocclusion. This section discusses most anterior crossbites. When the front teeth are crossbited, the molar relationship is mostly mesial, which is called Angle's Class III malocclusion.

① Since anterior crossbite tends to worsen with growth, early correction is particularly important.

② Anterior crossbite, especially skeletal anterior crossbite cases, may recur with growth and development after correction. Therefore, many cases need to be treated in stages, and the correction time is relatively long.

deciduous teeth stage

Teeth replacement period

Early permanent teeth

Remove the cause

Deal with problems that arise during the dentition period in a timely manner

Expander correction

Lingual tilt of the mandibular anterior teeth: You can use a mandibular lip stop to spread the lower lip and break the internal and external force balance of the mandibular anterior teeth. The tongue muscle force promotes the labial movement of the mandibular anterior teeth, thereby reducing deep overjet.

growth modification treatment