Surfaces of Teeth and Directions in Relation to Oral Cavity - Axial: A plane parallel to the surface of a tooth. - Buccal: The side of a tooth adjacent to the inside of the cheek. - Cervical: The narrowing of the contours of the tooth surface at or near the CEJ. - Coronal: The direction toward the crown of a tooth. - Distal: The direction toward the gingiva beyond the most posterior tooth in each quadrant. - Lingual: The side of a tooth adjacent to the tongue. - Labial: The side of a tooth adjacent to the inside of the lip. - Palatal: The side of a tooth adjacent to the palate. - Vestibular: The side of a tooth adjacent to the inside of the cheek or lips.

Directions in Relation to Midline and Specific Terms for Teeth - Mesial: The direction toward the anterior midline in a dental arch. - Distal: The direction toward the gingiva beyond the most posterior tooth in each quadrant. - Midline: An imaginary vertical line dividing the left and right sides of the mouth at the teeth. - Superior: The direction toward the head. - Inferior: The direction toward the feet. - Incisal: The direction toward the biting surface of anterior teeth. - Occlusal: The direction toward the biting surface of posterior teeth. - Proximal: The surfaces of teeth that normally lie adjacent to another tooth. - Marginal: The edge of tooth structure that is prepared to meet the edge of a prosthetic crown. - Lateral: A tooth which is away from the midline.

Dental Quadrants and Sextants - Upper right quadrant: Upper right first incisor to upper right wisdom tooth. - Upper left quadrant: Upper left first incisor to upper left wisdom tooth. - Lower right quadrant: Lower right first incisor to lower right wisdom tooth. - Lower left quadrant: Lower left first incisor to lower left wisdom tooth. - Sextant: One of six groups of adjacent teeth.

Combining of Terms - Combining forms can be used to create terms for directions and axes in dentistry. - Examples of combining forms include 'mesio-' for 'mesial' and 'disto-' for 'distal'. - The coronoapical axis is the long axis of a tooth. - Combining forms can be combined to create terms such as 'apicocoronal' (AC) and 'buccoapical' (BA). - Abbreviations for combined terms should only be used in specific contexts and when explicitly defined.

Abbreviations and Ambiguity - The abbreviations for combined terms in dentistry are often ambiguous and not specific to these terms. - Some abbreviations are not even one-to-one specific within the list of combined terms. - Spelling out the combined terms is generally recommended. - Abbreviations should be used sparingly and only in restricted contexts. - The abbreviations can help avoid extensive repetition, especially in academic articles.

Note: The references have been excluded from the groups as they are not directly related to the content organization.