Under the bridges section and tooth movement you show how upper teeth drift down, but it also needs to include the caries that often develops between the teeth that drop down and the tooth still in occlusion.

Also in bridges section the tooth movement that most often occurs, but is not shown, is the tipping of lower molars. Most commonly loss of a lower first molar leads to tipping and the interproximal decay on the distal of the second molar and mesial of the third molar.