NS-ReRCT max premolars Flashcards
What is the number of root canals in maxillary/ mandibular premolars? List all major morphological anomalies associated with maxillary/mandibular premolars.
Anatomical knowledge, including the number of root canals, is important for all root canal treat- ment, especially when locating the root canal orifice. Table 17.1 presents Vertucci’s classification and number of root canals in maxillary/mandibular premolars (Vertucci 1984). Knowledge of the variety of anomalies associated with these teeth is also necessary. For example, mandibular premolars occasionally exhibit dens evaginatus that causes pulpal infection and periapical periodontitis (Cleghorn, Christie & Dong 2007). While rare, mandibular 1st premolars may also present C‐ shaped canals (Cleghorn et al. 2007).
What are the differences between RCT and initial treatment? What should a practitioner be cautious of before starting re‐treatment?
One of the fundamental differences between root canal re‐treatment and initial treatment is that re‐ treated teeth contain previously filled material.The removal of this material comprises the first impor- tant step of re‐treatment protocols. Various methods to remove material have been advocated such as the use of hand files, nickel‐titanium rotary files, and ultrasonic instruments with or without the adjunc- tive use of a solvent.
Moreover, iatrogenic mishaps such as ledge formation, perforation, and broken instruments may have occurred during previous treatment, making sufficient cleaning and shaping difficult to achieve in re‐treatment cases.
Is complete removal of previously filled gutta‐ percha from the root canal possible?
Although one of the aims of re‐treatment is to completely remove the previously filled material, the complete removal of all material, including the sealer, remains a challenge (Duncan & Chong 2008).
What is the success rate of premolar root canal re‐treatment? What is the difference in success rate between root canal re‐treatment and initial treatment?
It should be noted that the success rate of re‐ treatment is lower than that of initial treatment.The success rate of premolar root canal re‐treatment (Table 17.2) has been reported to be between 65% and 71.8% (Ng, Mann & Gulabivala 2008), compared with 80.7% and 86.2% with initial treatment (Ng et al. 2007). Moreover, re‐treatment cases where the tooth has experienced iatrogenic mishaps (e.g., ledge formation) during previous treatment have a significantly reduced success rate compared with cases without iatrogenic difficulties (Gorni & Gagliani 2004).
What condition should a practitioner distinguish from periapical periodontitis before initiating root canal re‐treatment?
Premolars, especially maxillary premolars, are susceptible to vertical root fracture. Differential diagnosis is necessary before re‐treatment is initiated. Common signs and symptoms of vertical root fracture are localized deep periodontal pocket and a sinus tract that is located coronally, close to the gingival margin (Tamse 2006; Tsesis et al. 2010). The most frequent radiographic appearance of a vertical root fracture is the “halo” lesion, which is a combination of periapical and perilateral radiolu- cency surrounding the root (Tamse 2006;Tsesis et al. 2010). If any of the aforementioned features are detected at diagnosis, a practitioner should suspect vertical root fracture.
