15: Bilateral crossbite

15 Bilateral crossbite

Case 1

Summary

Jean has just turned 12. She presents with bilateral buccal crossbites (Fig. 15.1). What are the possible causes and how could it be managed?

image

Fig. 15.1 Case 1: Anterior occlusion at presentation.

History

Complaint

Jean does not like the ‘narrow’ appearance of her upper teeth, especially when she smiles.

History of complaint

Her mother says that Jean’s ‘baby’ teeth had the same appearance and she also has a similar appearance of her upper teeth to her daughter. Jean’s teeth erupted in the position they are in at present. There is no history of trauma to her upper jaw and birth was normal.

Medical history

Jean is asthmatic and uses a salbutamol (Ventolin) inhaler. She is prone to upper respiratory tract infections and is unable to breathe through her nose. Her mother reports that she snores and is prone to day-time drowsiness, which her teachers have noticed. Otherwise she is well. Her mother wonders if the narrow appearance of Jean’s upper teeth is related in any way to her mouth breathing and snoring. She is keen to know if Jean’s mouth breathing and snoring could be improved by any brace treatment.

image What is the relevance of Jean’s mode of breathing to snoring and to her complaint?

Compulsive mouth breathing, due to inability to breathe through the nose, may contribute to an altered head posture and low tongue position; this may lead to unopposed action of buccinator musculature and bilateral narrowing of the upper arch creating bilateral buccal crossbites.

Inability to breathe through the nose is also linked with snoring, which is associated with sleep apnoea, a major cause of day-time drowsiness. Prolonged inflammation of the nasal mucosa associated with allergies (in Jean’s case there is a history of asthma) or chronic infection (she is prone to upper respiratory tract infections) could produce some degree of nasal obstruction and lead to mouth breathing. The normally large pharyngeal tonsils or adenoids in children may also contribute.

Key point

Mouth breathing may contribute to altered head posture, low tongue position and bilateral buccal crossbite, but it is not the sole or even the major cause of such crossbites.

Dental history

Jean is an irregular attender at her general dental practitioner. She has fissure sealants to several molar teeth and one filling. There is no history of digit-sucking.

image How may a digit-sucking habit cause a buccal segment crossbite?

This is given in Table 14.1 (p. 63).

Social history

Jean has two younger sisters. Neither of them have had orthodontic treatment and neither of them have teeth like hers.

Examination

Extraoral

Jean has a Class 1 skeletal pattern with slightly increased FMPA and no facial asymmetry. Lips are incompetent. There are no signs or symptoms associated with the temporomandibular joints.

Intraoral

image The appearance of the teeth on presentation is shown in Figures 15.1 and 15.2. Describe what you see

Fair oral hygiene with generalized marginal gingival erythema.
image visible (please note image are also erupted).
All teeth visible appear caries-free; amalgam restoration in image.
Moderate lower arch crowding; image appear slightly small (contact point displacements were 3 mm between image and image; also between image and image); mild upper arch crowding
Class I incisor relationship; average and complete overbite; upper and lower centreline shifts (upper appears to the left, lower to the right); image in crossbite.
Molar relationship Class I on right and Class III on left with bilateral buccal crossbite affecting image.
image

Fig. 15.2 (A) Case 1: Right buccal occlusion.

image

Fig. 15.2 (B) Case 1: Left buccal occlusion.

image What are the possible causes of bilateral buccal crossbite?

Factors implicated in the aetiology of a bilateral buccal crossbite are given in Table 15.1.

Table 15.1 Possible causes of bilateral buccal crossbite

Bilateral buccal crossbite Possible causes
Skeletal Mismatch in relative widths of arches or anteroposterior discrepancy (commonly associated with Class III malocclusion)
Soft tissues Possible role of adenoids/tonsils (see text)
  Low tongue position possibly due to altered head posture associated with mouth breathing
  Scar tissue of cleft repair restraining growth in upper arch width

Investigations

image What investigations would you undertake in relation to the bilateral buccal crossbite? Explain why.

Clinical

It would be important to ascertain if there is an associated mandibular displacement, although this is rare with bilateral crossbites. It is more usual to have a mandibular displacement associated with a unilateral buccal crossbite.

No mandibular displacement was noted.

Radiographic

A dental panoramic tomogram would be useful to determine the presence, position and form of unerupted third molars. A lateral cephalometric radiograph will also be required (to ascertain the angulation of the upper and lower incisors to their respective dental bases).

The dental panoramic tomogram indicated four third molars of good form and position to be present.

The cephalometric findings were as follows:

SNA = 81°; SNB = 79°; MMPA = 28°; 1 to maxillary plane = 113°; image to mandibular plane = 93°; interincisal angle = 138°; facial % = 56%.

image What is your interpretation of these findings?

Relative to mean values for Caucasians, SNA is normal; SNB is slightly increased; ANB (SNA − SNB) = 2°, indicating a Class I skeletal pattern; MMPA is slightly increased, 1 to maxillary plane is increased, so upper incisors are slightly proclined; image to mandibular plane is normal; interincisal angle is slightly increased; facial % is slightly increased.

All values are within the normal range for Caucasians.

Diagnosis

image What is your diagnosis?

Class I malocclusion on a Class I skeletal pattern with slightly increased FMPA and no facial symmetry. Generalized marginal gingivitis. Moderate lower labial segment crowding: mild upper labial segment crowding with 2’s in crossbite; upper and lower centreline shifts. Molar relationship Class I on right; Class III on left with bilateral buccal crossbite affecting image.

image What is the IOTN DHC grade (see page 203)?

3d – due to contact point displacement between image and image; also between image and image.

Treatment

image What are the aims of treatment?

To improve oral hygiene.
To correct the bilateral buccal crossbite.
To relieve upper and lower arch crowding.
To align upper and lower arches with centreline correction.
To correct the left buccal segment relationship to Class I.

image What treatment would you provide?

Oral hygiene instruction by hygienist. Provided the marginal gingivitis is corrected then proceed to correction of the bilateral buccal crossbite (the need for extractions for relief of crowding and centreline correction should be reviewed following crossbite correction).

image What options are there for management of the bilateral buccal crossbite? Which would you choose?

The options are given in Table 15.2. In view of the severity of the crossbite and the desire to simultaneously, if possible, improve nasal breathing, rapid maxillary expansion (RME) would be the preferred choice of treatment.

Table 15.2 Management options for bilateral buccal crossbite

Management option Indications Comments
Accept and monitor Patient not keen for correction. Not an option here as Jean is keen for correction
Part of underlying skeletal III problem which is likely to worsen with mandibular growth, especially in males
Removable appliance with midline screw or heavy midline spring Primary/early mixed dentition Rate of expansion must be quite slow and force employed low: otherwise retention of appliance compromised by higher expansion forces
Compliance with wear and activation may be problematic
Not cost-effective as often lengthy time required to produce desired expansion
Quadhelix Preferred approach in early mixed dentition Made of 1 mm stainless steel wire attached to bands cemented to molar tooth on each side
3–5 mm maxillary expansion required (mainly dental but some skeletal expansion) Delivers few hundred grams of force
Teeth preferably tipped palatally but molar inclination may be adjusted with fixed appliances later Produces efficient slow expansion
May derotate />

Only gold members can continue reading. Log In or Register to continue

Related posts:

  1. 27: Facial swelling and dental abscess
  2. 39: Gingival bleeding and enlargement
  3. 3: Absent upper lateral incisors
  4. 6: Palatal canines
  5. 14: Posterior crossbite
  6. 38: Dentinogenesis imperfecta

Stay updated, free dental videos. Join our Telegram channel
Tags:
Jan 2, 2015 | Posted by in Orthodontics | Comments Off on 15: Bilateral crossbite

VIDEdental - Online dental courses
Get VIDEdental app for watching clinical videos