The first image shows the usual appearance of a tooth with the grooves which may sometimes have discolouration or stains. Then the next image shows the same tooth which has had some preparation with air abrasion. Air Abrasion is a micro sandblasting technique. This treatment step has showed up some brown staining which is tooth decay. A pink bacterial stain has been used which will stain areas where bacteria have infiltrated into the tooth. We have proceeded to remove this staining to prepare the tooth for a filling and then finally the completed resin filling.
Results will vary. All invasive procedures carry risks. You should seek a second opinion prior to treatment.