Objectives

At the end of this chapter, the reader should understand the aims of root canal instrumentation, have knowledge about the properties and indications of hand and rotary instruments and be able to formulate a strategy to treat curved root canals.

Introduction

A 68‐year‐old male patient was referred by his general dentist to a specialist endodontic practice for root canal treatment of his lower right second mandibular molar (LR7).

Chief Complaint

The patient was pain free but complained of the presence of a ‘gumboil’ adjacent to the LR7 for the last few weeks.

Medical History

Unremarkable.

Dental History

His dentist had replaced a defective subgingival restoration four months previously. The patient then developed a poorly localised ache in the jaw, which resolved after a gingival swelling appeared next to the tooth. The first molar (LR6) had been extracted as a teenager and the LR7 had tilted into the first molar’s position.

Clinical Examination

There were no remarkable extraoral findings. Intraorally, there was a buccal gingival swelling and a sinus tract adjacent to the LR7. There was a localised mid‐buccal periodontal probing defect deeper than 10 mm (Figure 4.6.1), with periodontal probing depths of 1–3 mm elsewhere in the mouth. The LR7 was restored with a disto‐occlusal (DO) composite restoration with poor marginal adaptation and was unresponsive to thermal sensibility tests. The rest of his dentition was moderately restored.

Radiographic Examination

• Alveolar bone heights within normal limits.
• LR7 had a DO restoration with subgingival distal caries, a calcified pulp chamber with long mesial and distal roots with severe curvatures in the apical third. Both apices were associated with an apical radiolucency that extended into the furcation area (Figure 4.6.2a).

Diagnosis and Treatment Planning

A diagnosis of pulp necrosis and asymptomatic apical periodontitis with suppuration associated with the LR7 was reached.

The treatment options for the LR7 were:

• No treatment.
• Non‐surgical root canal treatment and cuspal coverage restoration.
• Extraction (and replacement).

The patient was keen to have root canal treatment to prevent further worsening of his symptoms and retain the tooth.

Treatment

The restorability of the tooth was investigated by removal of the existing composite restoration and distal caries. A gingivectomy with electrosurgery was carried out to expose the distal subgingival cavity margin. The DO cavity was restored with a resin‐modified glass ionomer cement.