The tissue at the gumline of the tooth with the red arrow is not only very red but it is missing what is called the "attached tissue." Without this tissue, which is very pink, bone loss is more likely to occur. This patient does have attached tissue on the other teeth, which is from the neck of the tooth to the line that the green arrows are pointing to.
Tissue was taken from the roof of the patient's mouth and "grafted" to the area shown by the green arrows. Compare the image to the right with the image above. The tissue is much pinker and, therefore, healthier in the above image. The treatment, which took one appointment, should mean that this tooth will be of service to this patient for many more years to come.