Other Useful Auxiliaries
Leveling and alignment can be associated with anterior and lateral bite opening. If the tongue starts to interpose in the space, resolve of the opposite can be difficult and tongue habits may develop and may become permanent. An initially simple habit can potentially create a difficult treatment situation. For patients presenting with a habitual tongue thrust, we find that one of the more efficient ways of dealing with this to use prefabricated pads with spikes attached ( Fig. 8.10 ). We recommend using a continuous ligature, which is fitted around each individual attachment; this prevents inadvertent swallowing or aspiration of the lingual attachments.
The spikes may initially be uncomfortable for the patient, and it is advisable to inform and instruct the patient accordingly. Each time the tongue assumes its potentially harmful position the patient is made aware of the spike due to the discomfort. Over time, this leads to the tongue being trained to adopt a different, corrected position. In our experience, the tongue interposition tends to disappear after a short time, but we find it best to leave the spikes in place for at least several months in order to prevent relapse of the tongue interposition.
The locking mechanism in SLBs can be damaged if excessive force is used. This also applies, with occlusal forces when patients bite on brackets in centric occlusion or during mastication. The operator should therefore carefully check for any occlusal interference, particularly if teeth directly occlude on the SLB’s locking mechanism. If this is the case, we recommend either using an anterior bite plane or a posterior bite elevator. Careful evaluation of the temporomandibular joint is advisable before these auxiliaries are applied. When planning bite opening with auxiliaries, it is also advisable to consider the growth pattern. A patient with a brachycephalic deep bite will benefit more from anterior bite elevators, as these allow molar extrusion, while posterior bite elevators invade the leeway space and can cause relative intrusion of the molars.
Bite elevators attached to the palatal surfaces of the upper front teeth are very useful adjuncts. By disoccluding the posterior teeth ( Fig. 8.11 ), they allow uninhibited vertical development of the alveolar processes. Anterior bite planes are particularly useful for patients with class II/2 malocclusions, as they allow simultaneous alignment of both upper and lower arches and bite opening. A reduced lower anterior facial height can be corrected with this approach, especially in combination with a mandibular reverse curve of Spee alignment wire or vertical elastics. The anterior bite planes need to be checked at each appointment, as they may have become ineffective. The proclination of the upper front teeth that is often associated with treatment for a class II/2 incisor relationship may move the attachments anteriorly and thus make them ineffective. Subsequently, the protective function for the lower front teeth may have been lost. The lower labial segment may actually fall behind the bite planes in such a way that alignment of the lower front teeth is prevented, as the posterior aspect of the bite planes constantly pushes the lower labial segment lingually.
Bite planes should not have a negative impact on the patient’s occlusion. If not used correctly, bite planes may force the lower jaw distally, preventing alignment of the lower labial segment, on the one hand, and worsening the sagittal discrepancy on the other. Bite planes may also increase stress on the temporomandibular joint. At the same time, the bite planes should be adjusted to prevent patients from shifting laterally on contact. We find that anterior bite planes can be an extremely useful adjunct to self-ligation treatment, particularly if the above recommendations are followed.
In our experience, the following two techniques have proved useful for manufacturing bite planes.
Anterior Bite Planes
Anterior bite planes can be purchased prefabricated from a number of manufacturers (e.g., Bite Turbo, Ormco), or they can be made to suit the patient’s individual needs. In our practice, we use a preformed mold system known as the Mini-Mold (Ortho Technology), which makes it very easy to fabricate and apply anterior bite planes.
Figure 8.12 is a step-by-step guide on how to fabricate and use the Mini-Mold system. Initially, the enamel surface has to be conditioned. The mold is then filled with the composite and positioned at the desired location on the palatal site of the upper anterior teeth. The composite is then light-cured. Bite planes that have been manufactured in this way are usually stable and do not break or debond. They can be easily adjusted and are also relatively easy to remove. Due to the color of the material, it is easy to recognize residual composite on the palatal surface of the teeth so it can be completely removed following bite opening. Added advantages of this technique in comparison with premanufactured bite-opening appliances (such as bite turbos) are its lower cost and the reduced risk of swallowing or aspiration.
Lateral Bite Planes
Lateral bite planes can be added to the occlusal surface after appropriate conditioning. Either glass ionomer materials or composite materials are suitable for this purpose. In our experience, we have found that a blue glass ionomer cement, Band Lok Blue (Reliance Orthodontics), or Triad VLC Gel (Dentsply) works quite well. The latter is available in a number of different colors. The coloring makes it easier to remove the composite at the end of treatment. Independent of the material and bonding choice, removal of posterior bite planes can often be time-consuming and cumbersome, especially if they have been applied directly to the mandibular occlusal surface.
Omitting the enamel conditioning makes composite removal easier, but the molars have to be banded when this technique is used. The bands are used for fixation of posterior bite planes in the following way: a long wire ligature is threaded around lingual cleats, and the wire runs over the occlusal surface and is then fixed around the buccal tube. Triad VLC Gel, a flowable composite, is then applied ( Fig. 8.13 ). To remove composite, the wire ligature is cut buccally and the posterior bite plane is lifted off the molar together with the ligature.
Case Study 8.1 (Fig. 8.14)
Patient: J.Z., male, age 13.
Diagnostic records: models, panoramic radiograph, lateral cephalometric radiograph, intraoral/extraoral photographs.
Main findings: palatally erupted tooth 13 in crossbite.
Treatment aims: alignment of the canine and correction of the crossbite, alignment of the mandibular incisors.
Appliances: self-ligating brackets, molar bands, posterior bite elevators.
Archwire sequence: 0.012 SE, 0.016 SE, 0.016 × 0.022 SE, 0.018 × 0.025 SE, 0.019 × 0.025 SS.
Alternative treatment strategy: n/a.
Active treatment time: 10 months.
Retention: three-dimensional retention followed by fixed retention.
Bite-opening using a posterior bite plane can be easily achieved by applying a ligature from the lingual to the buccal side. The composite is then added for bite opening. Using a flowable composite is ideal for this purpose. Removing the composite is relatively easy, as the bite plane is removed together with the ligature used to fix it to the occlusal surface.