Bite Reconstruction

Impact of dental occlusion

Dental wear is a part of the normal aging process, but it becomes unphysiological when it follows a specific pattern. There is always a reason for dental occlusion or general medical condition underlying unphysiological wear, usually both of these. Dentition that has worked well for a long time and needed only minor operations can start wearing down unphysiologically; this can go completely unnoticed because wear does not necessarily produce any observable symptoms. When dental wear progresses further, symptoms like muscle pain, headaches, pain in the jaw joint area, repeatedly cracking teeth and/or fillings and structures, tooth sensitivity, worsening of periodontitis (a severe inflammation of soft tissues surrounding the teeth), and teeth splitting may occur.

As a result of wear, the canines bearing the lateral movement load do not function properly or reduce the forces applied to the other teeth. Due to lacking canine guidance, the forces generated by bruxism will grow and increase the incidence of cracks and fractures in molars and premolars, in particular. Canine guidance does not always work even if wear is non-existent; this indicates malocclusion. In bruxism, the lack of canine guidance increases the activation of the temporal muscle and thereby also the tendency towards headaches in the temple area. 

Molars can wear down even if canine guidance functions properly. In this case, an extensive surface of the molars is usually covered with composite fillings. The softer the filling material is, the faster wear proceeds. When the molars rub together, they start wearing down. Inefficient canine guidance will extend the area of the rubbing teeth further. Composite fillings wear down fast compared to tooth enamel or teeth with ceramic structures. This process creates a vicious cycle of filling treatments with growing frequency as the surface of the composite filling gets thinner. The situation can lead to a phenomenon called super eruption.

It is impossible to make the composite filling thick enough, because, due to wear, the opposite tooth in the opposite arch tends to reach out too far into the filling in search of the lacking opposite force in its counterpart, the worn-down tooth. Therefore, there is a lack of free space between the two opposite teeth, and the surface of the worn-down tooth gets thinner, layer by layer.

As wear develops, the incisors (front teeth) also start showing signs of wear, which indicates that occlusal wear has progressed further. The incisors can also wear locally without affecting the occlusion as a whole; this happens, for example, in habitual nail biting. When the whole dentition is affected, the situation often starts worsening at an accelerated pace. This is because the harder enamel wears away and the softer dentin, which is more prone to wear, is exposed on the chewing surfaces. The progress of wear is particularly rapid in situations that involve, for example, untreated sleep apnea or reflux disease. Moreover, frequent chewing of bubble gum can cause severe tooth wear.

Highly localized tooth wear also occurs when the opposite biting surfaces consist of materials that are significantly different. Of course, each case is individual and depends on the tooth in question, the location, and the surface area of the fillings. In rehabilitative treatment, every effort is made to select only the restorative materials that provoke wear as little as possible.

When a composite or amalgam filling has cracked or a new cavity has appeared at the edge of a filling, a more durable structure is required. In molars and premolars, the composite fillings ranging from one interdental space to another or those replacing an entire biting surface and edge are too large to support the residual dental tissue. These large fillings are also prone to wear. As a consequence of high masticatory forces, this kind of structural material mismatch easily leads to cracking of the remaining tooth edges and leaking seams in composite fillings. In most cases, this kind of cracking progresses from the corner of the bottom level of the filling diagonally towards the gum line. If the bottom of the filling has already reached the gum line, the remaining tooth edge will crack even below this level. This type of crack is catastrophic, and removing the tooth is usually the only option. Since cracking starts under the filling, it is often detected too late. A careful analysis of bite and fillings may predict future problems with cracks. In this situation, old fillings need to be replaced by ceramic structures as a preventive measure. Dental ceramics are excellent materials for restoring molars and premolars.

Prosthetic treatment

Bite reconstruction and full-mouth rehabilitation are a couple of the most demanding procedures in prosthetic dental care. Therefore, the primary treatment is to try to prevent teeth and bite collapse through other methods. In full-mouth rehabilitation the whole dentition has to be treated in one way or another instead of treating individual teeth. Therefore, during the process, it is of utmost importance to pay attention to a large variety of different factors to achieve the best predictable result, both functionally and esthetically. Bite reconstruction using solid ceramic structures is an expensive treatment overall, but its benefits compared to more inexpensive treatments are considerable. In the long term, the ceramic structures will keep the bite virtually stable, whereas treatment with composite fillings has to be repeated after 5–15 years of use.

In bite reconstruction, the amount of the addition needed is measured. Usually 1–3 millimeters is sufficient to restore the worn-down teeth to their anatomic shape with the help of different structures. The need to raise the teeth is always defined individually and recorded as repeatable. The teeth are scanned, and based on these images, the treatment is planned with CAD. CAD is used to create an esthetically and functionally optimal dentition. The design is tested with the help of 3D printed models and molds. Then, the sequence of treatments can begin, or the amount of the addition can be increased or decreased further for optimal comfort and esthetics.

Bite reconstruction takes advantage of combinations of several methods (these are described in the SERVICES section). In most cases, both molars and premolars are crowned or restored with ceramic restorations. If the incisors also show wear, they can be restored either with the injection molding technique or ceramic veneers. If the incisors have fillings, too, they can be covered with ceramic crowns. If the dentition is severely worn-down, a crown lengthening surgery is required for setting the crowns. Extensive treatment of bite can be implemented for other reasons, also, than obvious wear. Deep traumatic bite can be treated with localized reconstruction of molars and straightening incisors with aligners. The cases are highly individual and require comprehensive planning.

When the bite treatment is completed, and when the patient has become used to the restored bite, it is time to make a bite guard. A bite guard will protect the structures and teeth against the damages of bruxism and thus lengthen the duration of the structures and the adhesion grip.