Book excerpt: The way of periodontal concept is indeed advanced how it had been within the past. We now have a more robust understanding of the etiological factors related to periodontitis, the mechanism involved in periodontal wound healing and inter relationship between patients factors (such as smoking and diabetes) and treatment outcomes. However some controversies associated with periodontology do exist. The rationale of controversy on a selected topic could also be associated with inadequate knowledge of the etiological factors, technical difficulties, and patient related factor affecting the treatment outcomes or some unknown factors. Hence I have tried to cover as number of these controversial topics in periodontology in this text book