Historical clue formulations

• Dental concern — 2023-12-26
• Exponential ___ (function in physics) — 2022-03-12
• Rot — 2022-02-13
• Canine's woe? — 2019-04-20
• Go downhill — 2015-04-12
• Cause of radioactivity — 2015-02-01
• Reason to drill — 2013-06-12
• Tooth problem — 2011-06-20
• Break down — 2010-06-09
• See 18-Across — 2009-12-19
• Tooth trouble — 2009-07-22
• Go bad, as teeth — 2009-03-30
• Tooth trouble — 2003-04-03
• What spots on 1-Down show — 2003-03-18
• Tooth trouble — 2001-12-29
• Tooth problem — 2001-01-02
• Tooth trouble — 1998-08-11
• Rot — 1997-10-15