Impact of cross-sectional root canal shape on filled canal volume and remaining root filling material after retreatment
Abstract
, . Impact of cross-sectional root canal shape on filled canal volume and remaining root filling material after retreatment. International Endodontic Journal.
Aim
To
assess the impact of cross-sectional root canal shape (CSRCS) on the
canal volume that can be filled and the root filling material that
remains following a subsequent retreatment procedure.
Methodology
A
total of 15 extracted two-rooted human maxillary premolars and 15
mandibular first molars were used. Both root canals in the premolars (N = 30) and the distal root canal in the molars (N = 15)
were prepared using ProFile instruments and filled by lateral
compaction using gutta-percha and AH Plus sealer. Canals were later
retreated using the last ProFile used for instrumentation followed by
two ProFiles of increasing size. Teeth were viewed in a μCT
scanner before and after each treatment step. Defined and validated
threshold levels were used to differentiate empty root canal volumes,
root dentine and root filling materials from each other. CSRCS was
defined as the averaged ratio between bucco-lingual and mesio-distal
canal diameter (round ≤ 1, oval 1–2, long oval 2–4 and flattened ≥ 4),
determined for each 1 mm over the total root length. Data were averaged
between the two canals in premolars, only the distal canals were
assessed in molars. Parametric and non-parametric tests were used to
statistically compare the data, alpha = 0.01.
Results
Canals
in premolars had a round CSRCS after preparation (1.0 ± 0.0), whereas
distal counterparts in molars were oval (1.6 ± 0.5). Significantly (P < 0.01)
more canal volume could be filled, and significantly less filling
material remained after retreatment in premolars compared with
mandibular molar distal canals. There was a high correlation between
CSRCS, filled canal volume and remaining filling material.
Conclusions
The endodontic procedures under investigation were significantly influenced by the cross-sectional root canal shape.
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