A 60-year-old man with large DO amalgam at #30 develops pain and mild swelling apparently apical to #29 (Fig.2).  Both teeth (having fused PARL (periapical radiolucency) *) have mild percussion with the tooth #29 having higher mobility.

The tooth #28 seems to have the canal split apically, which is easily identify with CBCT.

Fused PARL

Xin Wei, DDS, PhD, MS 1st edition 03/29/2018, last revision 03/31/2018