A novel approach to evaluate the effect of medicaments used in endodontic regeneration on root canal surface indentation

Bone Biology Laboratory http://www.iupui.edu/~bonelab/ Department of Anatomy and Cell Biology Indiana University School of Medicine Department of Biomedical Engineering IUPUIObjectives: To investigate the capability of a novel reference point indentation apparatus to test the indentation properties of root canal surface dentine treated with three intracanal medicaments used in endodontic regeneration. Materials and Methods: Immature human premolars were selected (n=22). Four specimens were obtained from each root and randomly assigned to three treatment groups and a control group. Each specimen was exposed to one of three treatment pastes (triple antibiotic (TAP), double antibiotic (DAP), or calcium hydroxide [Ca(OH)2] or neutral de-ionized water (control) for one or four weeks. After each time-interval, the indentation properties of the root canal dentine surfaces were measured using a BioDent reference point indenter. Two-way ANOVA and Fisher’s Protected Least Significant Differences were used for statistical analyses. Results: Significant differences in indentation parameters and estimated hardness between all groups at both time points were found. TAP treated dentine had the highest significant indentation parameters, followed by DAP treated dentine, untreated control dentine and Ca(OH)2 treated dentine, respectively. Furthermore, TAP treated dentine had the lowest significant estimated hardness, followed by DAP treated dentine, untreated control dentine and Ca(OH)2 treated dentine, respectively. Conclusion: BioDent reference point indenter was able to detect significant differences in indentation properties of root canal dentine treated with various medicaments. Clinical Relevance: The use of a reference point indenter is a promising approach to characterize the indentation properties of root canal surfaces without any surface modification. This might provide an in vitro mechanical measurement that is more representative of the actual clinical situation

Susceptibility of methacrylate-based root canal filling to degradation by bacteria found in endodontic infections

Objectives: To present a case of endodontic failure obturated with a methacrylate-based root filling material, Resilon/ RealSeal (RS). To determine if RS is susceptible to biodegradation by endodontically relevant microbes by a method known to show RS degradation. Method and Materials: Emulsions of RS were dispersed in agar with minimal bacterial nutrients in culture plates. Lipase PS served as a positive control. Pseudomonas aeruginosa, Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis, Porphyromonas asaccharolytica, Enterococcus faecalis, Streptococcus sanguis, Streptococcus mutans, Staphylococcus aureus, and Staphylococcus epidermidis were tested for their ability to biodegrade RS. The bacteria were inoculated in the plates and examined daily for RS degradation for 7 days. Results: Degradation of the emulsified RS manifested in the formation of clear zones around P aeruginosa, P intermedia, P asaccharolytica, S aureus, and S epidermidis. No degradation was seen with the other tested bacteria or in plates that did not contain RS emulsion. Conclusion: Endodontic pathogenic bacteria can degrade RS. These findings complement other work and suggest that the seal and integrity of root canal fillings obturated with RS may be impaired by a microbial insult