Terminology and Definitions - Anatomical terms: Teeth have two sections - crown and root. The line where these sections join is called the cementoenamel junction. The roots are surrounded by alveolar bone and covered by gingival tissue. - Clinical terms: The terms 'relative crown' and 'relative root' describe how much tooth remains surrounded by bone. In periodontal disease, bone loss reveals more of the root structure, reducing the crown-to-root ratio.

Clinical Importance - The crown-to-root ratio is important for tooth support within the bone. - Root length is longer than crown length, providing stability. - Bone loss affects root support and increases the height of exposed tooth structure. - A minimum 1:1 ratio is necessary for a favorable prognosis.

Models of Human Teeth - Teeth in the alveolar bone have longer roots than crowns. - Teeth experience horizontal and vertical occlusal forces, leading to bone resorption or apposition.

Gingival Tissue and Gingival Recession - The gingival tissue covers the roots and is about 1 millimeter thick. - Gingival recession is related to decreased crown-to-root ratio.

Related Dental Procedures and References - Crown lengthening is a dental procedure related to the crown-to-root ratio. - Post and core is another dental procedure relevant to the ratio. - References such as Czochrowska et al., Carranza's Clinical Periodontology, Trauma from Occlusion Handout, and others provide additional information on the topic.