The question about BS comes up many times about what does it do. This case demonstrates one of the key ingredients in my opinion of long term success of perio-rest cases. Calculus is located everywhere under CEJ's and concavities etc. If we simply do pocket elimination there is an excellent chance plaque will be allowed to accumulate in the same areas all over again. So by removing areas that cannot be maintained by the patient a significant improvement has occurred for the patient's ability to maintain their hygiene. Notice the large fenestration on the mesiobuccal of #4. Added connective tissue for protection to bone etc. TAKE A SECOND AND NOTICE ALL THE CALCULUS EVERYWHERE.