Sounds to me like you need an extensive supplement therapy program not just iodine. High CRP and homocystine are not normal and signs of impending cardiac disaster.
root canals are in almost every case infected and cause copious amounts of toxins to be released into the body. These toxins cause the body to burn through large amounts of antioxidants, especially vitamin C. Low C levels (among others) have been directly linked to high CRP/homocystine and cardiac health.
Personally I would stear clear of the recommended supplement. For starters its likely overpriced and the proprietary blend usually doesnt do anything anyway not to mention 138mcg of Iodine is nothing. it takes on average 50mg (yes thats MG) a day for 6-12 months before you reach sufficiency at 138mcg a day you never will.
Iodine WITHOUT selenium can exacerbate thyroid conditions. Selenium is a critical element in the conversion/creation of thyroxins AS WELL AS an essential nutrient for neutralizing the toxins created in the process and its these that damage the thyroid directly so ample selenium is essential.
All of that being said you can reach Iodine sufficiency but your thyroid will never produce the necessary amount of thyroxins while you are taking external thyroid meds because it doesnt have to, The body has various feedback mechanisms for nearly every hormone which it uses to adjust production accordingly to keep things where they should be. When the body cant product the hormones it should its generally because the feedback loop is somehow affected and/or the natural ingredients to do so are missing from the diet OR are not taken in at a rate to overcome toxic load imposed on the system.