<prompt> Intracoronal retainer placed in the abutment teeth has the following disadvantageIt is unaestheticThey cannot provide support and stabilityDifficult laboratory procedureDifficult to repair and replace  <response>: Internal or precision attachmentsAdvantages:Improved aesthetics, by elimination of a visible retentive component and vertical support.Disadvantages:Difficulty in repair and replacing.Greater cost to the patient.Inability to use in teeth having short clinical crowns and tissue-supported distal extension denture bases. 