sftc19 Download single image for 35mm slide. Download single PowerPoint screen.	Primary teeth may be retained beyond the normal exfoliation time. One reason for "over-retention" is the lack of a permanent successor. Another cause of retention is ankylosis, a condition in which the root surface becomes fused to the alveolar bone. The primary teeth most commonly ankylosed are the mandibular primary first and second molars, followed by the maxillary primary first and second molars. Extraction of the ankylosed tooth will allow for the eruption of the permanent tooth. Bruxism has also been identified as a factor in over-retention of primary teeth.
sftc20 Download single image for 35mm slide. Download single PowerPoint screen.	(Photo: ankylosed primary molar)
sftc21 Download single image for 35mm slide. Download single PowerPoint screen.	(Radiograph: ankylosed primary molar)