Improvement of root canal X-ray imaging by delmopinol pretreatment-assisted contrast media infiltration
Nayak, Satyaprasad C.
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This study applied spontaneously surface-active biofilm-penetration aids to un-instrumented tooth root canals to provide better infiltration of x-ray contrast media and development of digital images that would assist in instrumentation as well as identification of smaller channels present. Teeth that require endodontic treatment often present with multiple root canals having complex morphologies difficult to navigate with the aid of only conventional x-rays. Previous attempts to provide better images of these structures by pressure- or vacuum-applied contrast media, in pre-cleaned root canals, produced mixed results unlikely to support such applications in biofilm-compromised natural un-instrumented roots. Recent advances in development of biofilm-collapsing oral rinses, digital radiography, and desktop image analysis tools encouraged this new investigation of surfactant-assisted contrast media penetration of un-instrumented root canals, examining the outcomes by before-and-after image subtraction criteria for extracted human teeth viewed at 0 vs 30 degree angulations to the X-ray beam. US Food and Drug Administration (FDA)- and European Union (EU)-approved delmopinol, a morpholino-ethanol derivative, was selected after evaluation in a bench-scale model test system similar to that successfully used in prior endoscope cleaning studies, employing twisted fiberglass bundles compressed within transparent tooth-sized glass tubes for easy visualization. Sodium alginate gel surrounded and filled all the glass tube channels as a bacterial biofilm exudate surrogate, and gravity vs capillary flow tube transit measurements were made with 1% delmopinol, a 0.2% mouth rinse formulation marketed as DecapinolTM, a comparison surface-active-displacement solution (SADS) previously noted to improve root canal cleaning effectiveness, and iodine-rich fully water-soluble Reno-60 ® contrast medium in widespread clinical use. Extracted teeth were mounted in a silicone resin and placed in a wooden jig for standardized angulation during radiography. The main study used a cross-over design where 13 teeth were radiologically examined as-received and after access opening of the pulp chambers, before and after application of Reno-60 ® . The access-opened teeth were water-stored and examined again, and then were divided into two groups, each subjected to either 1% delmopinol or SADS as a first pretreatment prior to Reno-60 ® addition and digital radiography at 0 and 30 degree angulations. After Reno-60 ® removal, the teeth were subjected to second pre-treatments by the alternative reagent and then Reno-60 ® re-applied prior to additional radiography. All radiographic images were digitally stored and then subjected to pair-wise digital subtractions using Adobe PhotoShop CS for comparison of visualized canal areas. Results were statistically examined using SPSS software and applied t-tests. Statistically significant differences were found favoring 1% delmopinol pretreatment as a contrast media penetration aid for root canals, with even better results after a secondary application of SADS in confirmation of earlier cleaning studies where SADS augmented cleaning effectiveness of other irrigant solutions. Delmopinol, uniquely capable of disrupting biofilm matrix polymers in its FDA- and EU-approved dental plaque dispersant applications, can be a helpful reagent in infiltration, visualization, navigation, and ultimately improved cleaning of endodontic structures.