Management of anterior open bite during full orthodontic treatment

Some general considerations for the management of anterior open bite during full-banded orthodontic treatment are included in this section. While non-extraction treatment is generally preferred in orthodontics, some open-bite cases may benefit from extractions, primarily to allow for eruption and retroclination of incisors. Some possibilities are as follows:

• If the upper and lower arches show crowding and/or protrusion, upper and lower bicuspid extractions can be considered.

• If the lower arch does not require extraction for lower incisor retroclination, and the molars are more than

3-4 mm Class II, extraction of upper bicuspids only can be considered (Case LJ, p. 184). This will allow for the retraction and retroclination of upper incisors.

• If the lower arch does not require extraction for incisor retroclination, and the molars are less than 3 mm Class II, extraction of upper bicuspids is a concern. It is most difficult to move upper molars forward 4-7 mm and keep their roots in an upright position. This is required for proper Class II molar occlusion. Upper second molar extraction can be considered in such cases, if good third molars are present. This allows for easy distalization of first molars, without opening of the mandibular plane.

• During bracket placement of open-bite cases, the upper and lower anterior brackets can be placed 0.5 mm more gingival than normal (p. 65). This simple procedure helps to achieve bite closure as treatment proceeds.

• It is not recommended that second molars be banded in the early and middle stages of treatment of open-bite cases, because this can lead to the extrusion of the premolars and first molars, and further bite opening. If second molars need to be banded for improved positioning or for torque control later in treatment, it is beneficial to leave curve of Spee in the posterior aspect of the lower arch and to step the archwire up to the second molars in the upper arch. This will minimize extrusion of first molars and bicuspids.

• Appliances described above such as tongue appliances, palatal bars, lingual arches, posterior bite plates, high-pull facebows, and vertical chin cups can be helpful in these cases. Also, tonsil and adenoid evaluation, as well as myofunctional therapy, can be considered.

• If Class II (Pigs 6.26 & 6.27) or Class III elastics are required, they should be attached posteriorly to premolars rather than molars. These 'short' elastics minimize the extrusive effect on the back of the arches.

• The removal of acrylic from the incisor area of the upper retainer is recommended, along with the placement of a small hole in the anterior region as a reminder for the tongue. Positioners can be considered during retention, because of their bite-closing effect (p. 31 I).

Short Class Elastics
Fig. 6.26 Short Class II elastics can be helpful in managing anterior open-bite Class II cases. Here, Class II elastics are carried to hooks on lower second premolar tubes.

Fig. 6.27 In this Class II anterior open-bite case, second premolars were extracted. Short Class II mechanics were applied to Kobyashi ties on the lower first premolars.

Open Bite Treatment

CASE MP_

A male patient, aged 12.7 years, with Class II skeletal bases (ANB 6°) and bimaxillary protrusion and proclination on an average angle pattern of MM 27".

The patient was in the late mixed dentition with all permanent teeth developing. There was some lower anterior crowding and an upper midline shift of 2 mm to the right. It was felt that dental correction could be achieved on a non-extraction basis. However, in order to retract the incisors and achieve facial profile improvement, a decision was made to extract all first premolars and manage the case as a maximum anchorage treatment. An upper palatal bar and a lower lingual arch were placed at the start of treatment. I leadgear support was used at night in order to achieve treatment goals.

Open Bite Treatment

Tooth leveling and aligning procedures were commenced with .016 HAN I' wires, followed by rectangular IIAN'I' wires. I lere, the case is seen with rectangular steel wires and passive tiebacks in place, prior to commencement of correction of overjet and overbite, followed by space closure.

Management Open Bite Open Bite Treatment Open Bite Treatment Anterior Open Bite Correction

M.P.Beginning 12.7 years 1/13/95

Open Bite Treatment

M.P.Beginning 12.7 years 1/13/95

SNA / 84 SNB 78 ANB/ 6 A-N FH 0 Po-N FH -10 WITS 1 GoGnSN 35 FM 28 MM 27 1 to A-Po 16 1 to A-Po 7 1 to Max Plane 125 1 to Mand Plane-' 98

Management Open Bite Overjet Correction Profile Picture

The patient was asked to wear a ')' hook type of headgear during the evenings and nights, together with Class II elastics. In this type of case, a ']' hook headgear can be helpful in both retraction and intrusion of upper incisors in order to achieve optimal facial profile change.

During space closure, the lower lingual arch was discontinued but the upper palatal bar remained in place to support upper anchorage.

After the rectangular wires had been in place for 2 months, bite-opening curves were introduced (p. 137).

Lower second molars (p. 136) were banded to assist in correction of the lower curve of Spec. I Iere, the case is seen after 16 months of treatment. The lower first molar bands were repositioned.

Management Open Bite

10"-20°of palatal root torque

10"-20°of palatal root torque

Anterior Stops Open Bite Open Bite Treatment

w Normal finishing procedures were followed, and appliances were removed after 23 months of active treatment.

m zn ro

Normal retention was provided, with the lower bonded

O retainer extended onto the second premolars.

H 73

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