title: Evaluation of New Cone-beam Computed Tomographic Criteria for Radiographic Healing Evaluation after Apical Surgery: Assessment of Repeatability and Reproducibility.
abstract: BACKGROUND
  Conventional 2-dimensional radiography uses defined criteria for outcome assessment of apical surgery. However, these radiographic healing criteria are not applicable for 3-dimensional radiography. The present study evaluated the repeatability and reproducibility of new cone-beam computed tomographic (CBCT)-based healing criteria for the judgment of periapical healing 1 year after apical surgery.
  
  
  METHODS
  CBCT scans taken 1 year after apical surgery (61 roots of 54 teeth in 54 patients, mean age = 54.4 years) were evaluated by 3 blinded and calibrated observers using 4 different indices. Reformatted buccolingual CBCT sections through the longitudinal axis of the treated roots were analyzed. Radiographic healing was assessed at the resection plane (R index), within the apical area (A index), of the cortical plate (C index), and regarding a combined apical-cortical area (B index). All readings were performed twice to calculate the intraobserver agreement (repeatability). Second-time readings were used for analyzing the interobserver agreement (reproducibility). Various statistical tests (Cohen, kappa, Fisher, and Spearman) were performed to measure the intra- and interobserver concurrence, the variability of score ratios, and the correlation of indices.
  
  
  RESULTS
  For all indices, the rates of identical first- and second-time scores were always higher than 80% (intraobserver Cohen κ values ranging from 0.793 to 0.963). The B index (94.0%) showed the highest intraobserver agreement. Regarding interobserver agreement, the highest rate was found for the B index (72.1%). The Fleiss' κ values for R and B indices exhibited substantial agreement (0.626 and 0.717, respectively), whereas the values for A and C indices showed moderate agreement (0.561 and 0.573, respectively). The Spearman correlation coefficients for R, A, C, and B indices all exhibited a moderate to very strong correlation with the highest correlation found between C and B indices (rs = 0.8069).
  
  
  CONCLUSIONS
  All indices showed an excellent intraobserver agreement (repeatability). With regard to interobserver agreement (reproducibility), the B index (healing of apical and cortical defects combined) and the R index (healing on the resection plane) showed substantial congruence and thus are to be recommended in future studies when using buccolingual CBCT sections for radiographic outcome assessment of apical surgery.
authors.affiliation: Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland. Electronic address: thomas.vonarx@zmk.unibe.ch.
authors.forename: Thomas
authors.initials: T
authors.lastname: von Arx
authors.affiliation: Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Simone F M
authors.initials: SF
authors.lastname: Janner
authors.affiliation: Department of Preventive, Pediatric, and Restorative Dentistry, School of Dental Medicine, University of Bern, Bern, Switzerland; Private Practice Limited to Endodontics, Bern, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Hänni
authors.affiliation: Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Bornstein
mesh_terms: D000328:Adult; D000368:Aged; D054893:Cone-Beam Computed Tomography / Q000295:instrumentation* / Q000379:methods*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D017063:Outcome Assessment, Health Care; D010483:Periapical Diseases / Q000000981:diagnostic imaging* / Q000601:surgery*; D019252:Radiography, Dental, Digital / Q000379:methods; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods; D019227:Tooth Apex / Q000000981:diagnostic imaging* / Q000601:surgery*; D014945:Wound Healing / Q000502:physiology*
keywords: Apical surgery; cone-beam computed tomography; healing indices; radiographic healing outcome; repeatability; reproducibility