Effect of Smear Layer on Endodontic Outcome
Condition: Apical Periodontitis
MeSH terms: Periodontitis; Periapical Periodontitis; Smear Layer
Study type: Interventional

Summary: 
      This study evaluated the effect of removal of smear layer on the success of primary root
      canal treatment.Patients requiring primary root canal treatment in mature mandibular first
      and second molars were allocated to either smear layer positive group and smear layer
      negative group.
    

Detailed description: 
      Patients requiring primary root canal treatment following the diagnosis of pulp necrosis in
      permanent mandibular first and second molars having radiographic evidence of periapical
      radiolucency (minimum size ≥ 2.0 × 2.0 mm) were included in the study. All patients were over
      18 years of age and diagnosis of pulpal necrosis was confirmed by negative response to cold
      and electrical tests, and absence of bleeding on entering the pulp chamber. Patients with
      systemic illness, history of analgesic intake within past 7 days, antibiotics in the last
      3months and patients who were pregnant were excluded from the study. Periodontally
      compromised teeth, previously accessed teeth, teeth that were not suitable for rubber dam
      isolation were also excluded from the study.

      Subjects were allocated to one of the two study groups: smear layer positive group (only
      2.5%NaOCl was used) - SP and smear layer negative group (17% EDTA+2.5%NaOCl was used) - SN.
      Using an equal proportion randomization allocation ratio, patients were assigned to the two
      groups using envelopes containing concealed assignment codes. It was ensured that neither the
      patient, nor the primary investigator was aware of the group till the time of final rinse.

      After administration of local anesthesia, rubber dam isolation of the involved tooth was
      done. Caries was excavated and access cavity prepared using carbide burs in high speed
      handpiece with copious irrigation.Debridement of the pulp chamber was done and all canal
      orifices identified.Working length was obtained with the help of electronic apex locator and
      confirmed radiographically.Hand files number 10, 15 and 20 were used till working length (WL)
      to prepare a smooth reproducible glide path.Canal preparation was done with the help of
      rotary NiTi files. In both groups, 2.5% sodium hypochlorite was used as irrigant after each
      instrument. All the irrigation procedures were performed using a 27 gauge side vented needle.
      After root canal instrumentation, 17% Ethylenediaminetetraacetic acid (EDTA) solution was
      also used to remove smear layer in smear layer negative group, while teeth in smear layer
      positive group was simply rinsed with 2.5% sodium hypochlorite. In both the groups ultrasonic
      activation of irrigant was done. An inter-appointment dressing of calcium hydroxide was
      given. The access cavity was then restored with intermediate restorative material (Dental
      Products of India).

      Patients were prescribed Ibuprofen 400mg with the instructions to take one tablet every 8
      hours in the event of pain.Patients were asked to record the severity of pain using 10 cm VAS
      scale with 0 depicting no pain and 10 depicting maximum pain imaginable. Patients were asked
      to make a mark on the line that represented their level of perceived pain every 24hrs for 7
      days following intervention.

      One week later, patients returned with the completed questionnaires.

      At the same appointment the intracanal dressing was removed with H-files and copious
      irrigation with 2.5% NaOCl in both the groups.

      17% EDTA solution was used to remove smear layer in smear layer negative group, followed by
      2.5% NaOCl while teeth in smear layer positive group were simply rinsed with 2.5% sodium
      hypochlorite.

      Ultrasonic activation of irrigant was done and canals were obturated with the GuttaPercha and
      Zinc Oxide-Eugenol based sealer in both the groups. After obturation, the cavity was restored
      permanently.Immediate post-operative radiograph was then taken using preset exposure
      parameters.Follow up clinical and radiographic examination was carried out every 3 months,
      till a 12 month period. The data gathered was analyzed using suitable statistical methods.
    

Intervention name(s): Root canal treatment with smear layer removal; Root canal treatment without smear layer removal
Intervention type(s): Procedure; Procedure
Intervention description(s): Canal were irrigated with Naocl and EDTA to remove smear layer; only sodium hypochlorite was used for irrigation
Other intervention name(s): irrigation with EDTA; irrigation with only NAOCL
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: EDTA; Postoperative pain; Pulp necrosis; Smear layer