Discoloration of roots caused by residual endodontic intracanal medicaments

Spectrophotometric insights: calcium hydroxide influences tooth discolorations induced by short-term application of antibiotic/corticosteroid pastes

OBJECTIVES

This in vitro study aimed to assess the influence of a calcium hydroxide dressing regarding the relative color change (ΔE) of enamel-dentin specimens previously exposed to antibiotic/corticosteroid pastes.

MATERIALS AND METHODS

Eighty bovine enamel-dentin specimens with a cylindrical central cavity were randomly allocated to four groups: NEG (empty), POS (blood), LED (Ledermix), and ODO (Odontopaste) (n = 20 each). The materials were applied and sealed with self-adhesive resin luting material. After 3 weeks, the materials were removed and a calcium hydroxide (Ca(OH)₂) dressing was placed in all cavities. After a further 3-week storage period, the cavities were restored with resin-based composite. Spectrophotometric color measurements were taken over 6 months, and ΔE values were calculated. A Tukey's multiple comparison test was performed to assess significant differences within the treatment groups (p < 0.05).

RESULTS

Tooth discolorations were present after 3 weeks in LED (ΔE 29.14 ± 6.55) and POS (ΔE 18.05 ± 7.03); NEG and ODO remained color stable (ΔE 3.2 ± 1.36 and ΔE 2.3 ± 1.16). The 3-week Ca(OH)₂ dressing decreased discolorations of POS (ΔE 15.93 ± 6.63; p = 0.37), whereas LED showed a further significant increase (ΔE 39.55; p < 0.0001). Between the end of the Ca(OH)₂ dressing and the final restoration no significant color changes were observed in any group (p > 0.9).

CONCLUSIONS

Discolorations induced by LED progressed during the Ca(OH)₂ dressing despite careful removal of all residues.

CLINICAL RELEVANCE

Calcium hydroxide might negatively affect the discoloring potential of Ledermix. This highlights the need for direct intracanal application methods of Ledermix ensuring a material-free access cavity or alternative antibiotic/corticosteroid pastes such as Odontopaste should be used.

Comparison of Two Different Methods in the Removal of Oil-Based Calcium Hydroxide From Root Canal System: A Triple-Blinded Randomised Clinical Trial

OBJECTIVE

To compare the effectiveness of rotary master apical file (RMAF) with ultrasonic activation of endodontic file (UAF) in the removal of silicon oil-based calcium hydroxide (SOBCH) from the canal.

METHODS

Ethical review committee approval and informed consent was obtained. 60 cases with necrotic teeth in which silicon oil-based intracanal medicament (Metapex) was to be placed were randomised in one of the two groups using sealed envelopes containing assignment codes for medicament removal: RMAF and UAF group. After standard protocol of coronal access, cleaning and shaping, silicon oil-based SOBCH was placed using a Lentulo spiral. A periapical radiograph was taken after SOBCH placement to check for adequate adaptation. On 7th day, after instrumentation and medicament removal according to respective group, a second radiograph was taken to evaluate the effectiveness. Effectiveness was calculated using a graded scale in which 0 and 1 are effective and 2 and 3 are ineffective cleaning. Teeth were statistically analyzed using the Mann Whitney U and Chi-square test.

RESULTS

There was no statistically significant difference in the removal effectiveness of group RMAF and Group UAF at coronal (P=0.74) middle (P=0.71) and apical third (P=0.68). According to the graded score both techniques were equally effective in cleaning at all thirds of canal (RMAF=Apical: 1.09+-0.70, Middle: 0.61+-0.80, Coronal: 0.33+-0.48 and UAC=Apical: 1.00+-0.77, Middle: 0.52+-0.74, Coronal: 0.28+-0.46). Effectiveness of SOBCH removal using the two methods was not statistically significant between maxillary and mandibular teeth (P=0.35).

CONCLUSION

Both the removal methods, Ultrasonic activation of file and Rotary master apical file, for SOBCH were equally effective in all the thirds of canal. And none of the techniques were able to completely remove the SOBCH. Effectiveness of SOBCH removal using the two methods was not statistically different between maxillary and mandibular teeth. (EEJ-2020-07-183).

Mechanisms of Staining with Demeclocycline and Doxycycline Root Canal Medicaments

Tetracyclines are a unique class of antibiotics which also have additional effects including anti-inflammatory, anti-resorptive and substantive within the root canal. There has been a long-held view that tetracycline medicaments discolour teeth and should be avoided. The evidence base around this topic was explored, including a review of the methodology used in laboratory studies. A search of PubMed, Medline and Scopus databases was conducted to identify studies of demeclocycline and doxycycline medicaments used in root canal therapy. An analysis of the methodology used in these studies was performed to determine if these replicate current clinical practice. The related literature on mechanisms of tetracycline stability and the effects of light, oxidation, moisture and chemical interactions was examined. Studies investigating the effects of Ledermix paste on segments of bovine dentine and avulsed or reimplanted teeth as well as combinations with other antibiotics were excluded from this review. Even though demeclocycline medicament pastes were introduced in 1962, the first laboratory studies of discolouration were not done until 2000. All later studies followed a similar approach, which included exposure to sodium hypochlorite for up to 30 minutes and storage in moist conditions with 100% humidity. Staining during dark storage and enhanced staining on exposure to light were reported, indicating multiple pathways of degradation of demeclocycline and its reaction products. Light, moisture and oxidation are the key factors which drive discolouration from demeclocycline. Clinical issues from tooth staining can be prevented by removal of medicament pastes from the access cavity, and placement of a sound interim restoration. Use of a doxycycline paste obviates concerns of staining. Laboratory assessments of the potential for staining should replicate in vivo conditions.

Dispersion of near-infrared laser energy through radicular dentine when using plain or conical tips

The aim of this study was to investigate the influence of tip design on patterns of laser energy dispersion through the dentine of tooth roots when using near-infrared diode lasers. Diode laser emissions of 810 or 940 nm were used in combination with optical fiber tips with either conventional plain ends or conical ends, to irradiate tooth roots of oval or round cross-sectional shapes. The lasers were operated in continuous wave mode at 0.5 W for 5 s with the distal end of the fiber tip placed in the apical or coronal third of the root canal at preset positions. Laser light exiting through the roots and apical foramen was imaged, and the extent of lateral spread calculated. There was a significant difference in infrared light exiting the root canal apex between plain and conical fiber tips for both laser wavelengths, with more forward transmission of laser energy through the apex for plain tips. For both laser wavelengths, there were no significant differences in emission patterns when the variable of canal shape was used and all other variables were kept the same (plain vs conical tip, tip position). To ensure optimal treatment effect and to prevent the risks of inadvertent laser effects on the adjacent periapical tissues, it is important to have a good understanding of laser transmission characteristics of the root canal and root dentine. Importantly, it is also essential to understand transmission characteristics of plain and conical fibers tips.