The Phenomenon of Popov-Godon occurs when a tooth or teeth are lost and remaining teeth move towards the edentulous space. It is important to understand the effects of a gap on the remaining dentition. Overall it is recognised that a patient only needs to have 5 to 5 intact in both arches to be still able to function and eat adequately.
Loss of a tooth or teeth can cause the following to occur:
1. A process called overeruption of the opposing tooth or teeth can occur. This happens because there is no impediment from an opposing tooth as that is now missing. Overeruption of the opposing tooth can occur either with the alveolar bone intact or without the alveolar bone intact. This causes several problems as follows.
(a) If significant over eruption of the opposing tooth occurs, this means that it will be problematic to restore the gap in the edentulous area of the mouth. There will be not enough room to place a tooth of the same size as was lost. You can therefore either accept that a smaller height of tooth will go into the edentulous space as a replacement or you can adjust the opposing tooth which has over erupted to restore the vertical space. In severe cases where excessive overall reaction has occurred, it can even be necessary to extract the opposing tooth which has over erupted.
Effects on the over erupting tooth include risks of periodontal disease and dental caries. Periodontal disease and caries occurs because of changes to the contact points due to food packing around the open tooth contacts. Furthermore, if any root is exposed, this can make the tooth more vulnerable to dental caries and also periodontal disease from furcation involvement.
2. The tooth or teeth distal to the gap will tend to tilt or migrate mesially. This has the effect of reducing the width of the edentulous space and creating problems in restoring the gap using teeth or tooth of the same dimensions as there was originally. As above, one can either accept a reduced gap or one can try to restore the gap by modifying the tooth/teeth which are encroaching the edentulous space.
The width of the edentulous space is reduced by either the tooth tilting so that the crown tilts but the root is still in the same position or the whole tooth can migrate.
As above, common problems arise because the tooth which has moved can be more susceptible to dental caries and periodontal disease. Susceptibility to dental caries and or periodontal disease is increased due to food packing around open contact points.
Additionally, it is not uncommon to find that occlusal changes are now created such as premature occlusal contacts and an unbalanced bite.
As part of restoring the gap with either a bridge or an implant, one also has to address the occlusion so that the occlusion is free from interferences and is balanced. Occclusal interferences and premature contacts can cause mandibular deviations and also excessive strains on the TMJ. Likewise, it can cause the periodontal ligament of a particular tooth to respond by thickening and widening resulting in clinical mobility.