The relationship between the portion of the tooth coronal to the alveolar crest of bone compared with the portion embedded in it, has always been regarded as a vital aid in predicting the prognosis of teeth. However, controversy persists as to its impact on diagnosis and treatment planning. This article critically reviews the available literature on the crown-to-root ratio assessment and the shift in paradigm related to the criteria for evaluation of abutment use of periodontally compromised teeth. Also various treatment modalities present to improve an unfavourable crown-toroot ratio have been stated. A Medline search was completed for the time period from 1961 to 2005, along with a manual search to locate relevant peer reviewed articles and textbooks published in English. There was a scarcity of evidence-based research on the topic. Although the use of crown-toroot ratio along with other clinical indices may offer the best clinical predictors, no definite recommendations could be ascertained.