Radiographic Findings

Teeth Identified

1. Mandibular Second Molar - the standing tooth
2. Mandibular Third Molar - severely impacted in a mesioangular/horizontal position, wedged directly against the second molar

Diagnosis

Second Molar (37 or 47)

• Deep distal caries - large radiolucency on the distal crown surface, extending subgingivally, in close proximity to or involving the pulp chamber
• Probable pulpal necrosis - the depth and extent of decay strongly suggests pulpal involvement
• Chronic periapical periodontitis - diffuse periapical radiolucency around the root apices, consistent with pulp-derived infection
• Severe localized bone loss - on the distal aspect at the second/third molar interface, significantly apical to the CEJ

Third Molar (38 or 48)

• Mesioangular/horizontal impaction - crown impinging on the distal cervical area of the second molar
• Mild pericoronal radiolucency - possible pericoronitis or follicular space widening
• Root morphology - appears curved/dilacerated, in proximity to the inferior alveolar canal (IAC)

Management Plan

Step 1 - Surgical Extraction of Impacted Third Molar

• Primary intervention to eliminate the plaque trap and chronic inflammatory stimulus
• CBCT recommended before surgery to assess the exact relationship of the third molar roots to the inferior alveolar nerve (the 2D image suggests close proximity)
• Surgical approach with mucoperiosteal flap, bone removal, and sectioning of the tooth

Step 2 - Management of the Second Molar

• Root canal treatment (likely multi-rooted with mesial and distal canals)
• Full-coverage crown restoration after RCT, especially given the loss of distal marginal ridge
• Periodontal review once bone healing occurs post-third molar extraction

Step 3 - Periodontal Follow-up

• Post-extraction bone fill on the distal of the second molar should be monitored
• Early third molar removal historically leads to better bone regeneration on the distal of the second molar

Key Clinical Notes

• The impacted third molar is the root cause of this presentation - it created a non-cleansable pocket that allowed progressive distal caries on the second molar
• Sequencing matters: remove the third molar first, then complete RCT on the second molar, to avoid reinfection of a freshly treated root canal
• If both teeth require extraction, consider future implant planning for the second molar site