What might cause space between teeth #29 and #30 in an old patient with limited occlusion?

The presence of space between teeth #29 and #30 in an older patient with limited occlusion is best attributed to the lack of occlusion or mesial drifting of the premolars. In an individual with limited occlusion, the absence of proper contact between opposing teeth can result in a lack of functional stimulation in that area. Consequently, neighboring teeth may drift or shift due to changes in the bite relationship.

If teeth do not engage properly in occlusion, the equilibrium of tooth positioning can be disrupted. This destabilization may lead to mesial drifting, where the adjacent premolars move towards the space created by migration or loss of tooth structure. This movement can contribute to the spacing observed between the teeth.

The other factors, while relevant in different contexts, do not primarily explain the specific situation of spacing due to limited occlusion as effectively. For example, loss of tooth structure may lead to other complications, but it wouldn't solely account for the space caused by occlusal problems and mesial drifting. Similarly, periodontal disease often presents with other clinical features rather than isolated spacing, and an infection would typically cause localized symptoms rather than drifting or spacing in the manner described.