Effect of sodium hypochlorite, isopropyl alcohol and chlorhexidine on the epoxy sealant penetration into the dentinal tubules

BACKGROUND

The sealer penetration into the dentinal tubules might be beneficial, especially in necrotic endodontic cases, as it provides the obstruction of the contaminated tubules.

OBJECTIVES

To determine the effect of 3 final irrigants (sodium hypochlorite (NaOCl), alcohol and chlorhexidine (CHX)) on the penetration of an epoxy sealer into the dentinal tubules.

MATERIAL AND METHODS

The study was carried out on 60 single-canal human teeth with straight roots. The root canals were prepared to the ISO 40/04 size, using the Reciproc® instruments. The teeth were divided into 4 groups (n = 15). The canals in each group were irrigated according to the following scheme: group 1 (control) - 5.25% NaOCl; group 2 - smear layer removal (40% citric acid (CA) and 5.25% NaOCl) and 5.25% NaOCl; group 3 - smear layer removal (as in group 2), and 40% CA, water and 98% isopropyl alcohol; and group 4 - smear layer removal (as in group 2), and 40% CA, water and 2% CHX. The root canals were filled using the vertical condensation technique with gutta-percha and the porphyrin-labeled AH Plus™ sealer. After 3 days, 1-milimeter-thick cross-section slices were cut from the roots at a distance of 2 mm, 5 mm and 8 mm from the apex. The sections were imaged under a confocal microscope and the sealant penetration depth into the dentinal tubules was measured.

RESULTS

The longest resin tags in all parts of the roots were found in group 4 (CHX), and the shortest in group 1 (control). The mean depth of the sealer penetration (in micrometers) was as follows: 21, 22 and 23 (group 1); 201, 231 and 374 (group 2); 170, 232 and 280 (group 3); and 330, 408 and 638 (group 4) in the apical, middle and coronal parts, respectively.

CONCLUSIONS

The final irrigation with CHX resulted in the deepest penetration of the epoxy sealer into the tubules. Isopropyl alcohol had the most negative impact on the sealer penetration into the tubules.

Real-time co-site optical microscopy study on the morphological changes of the dentine's surface after citric acid and sodium hypochlorite: a single-tooth model

BACKGROUND

To this day, the effects of sodium hypochlorite and chelating agents on the smear layer and on the dentine's surface, remain not fully examined. The study is aimed to analyze the dentine's surface treated with 40% citric acid and 5.25% sodium hypochlorite according to two irrigation protocols.

MATERIALS AND METHODS

The study employed a computer-controlled Nikon Eclipse LV100 optical microscope. Ten roots split longitudinally with canals prepared mechanically using the MTwo system to a size of 40/04 were observed. The root halves were divided into two study groups, one half in each of the groups. According to two irrigation protocols, the dentine's surface was irrigated with 40% citric acid and 5.25% sodium hypochlorite, separated with water. Dentine surface was observed in a fixed place and photographed in 500 × magnification after each irrigation stage. The obtained images were then analyzed using computer software (NIS-Elements AR, GIMP-2.6, ImageJ 1.45s).

RESULTS

Various speed of removal of the smear layer and varied morphological changes of the dentine's surface were observed in both examined groups. Double irrigation of the dentine with citric acid for 30 s resulted in complete removal of the smear layer, and double irrigation for 60 s resulted in increased mean diameter of the dentine tubules (degradation of the dentine's surface).

CONCLUSIONS

Double alternating irrigation with citric acid and sodium hypochlorite for 30 s yielded satisfactory results, while double irrigation for 60 s resulted in increased mean diameter of the dentine tubules. A real time assessment of the dentine's surface changes after both tested solutions can improve understanding of the phenomena that occur during the irrigation and as a result it might help to improve clinical outcomes in root canal treatment.

The impact of irrigation protocols on epoxy sealer penetration depth in dentinal tubules. Study involving laser confocal microscopy

The aim was to assess the impact of irrigation protocols ended with ethanol or chlorhexidine on AH Plus penetration into dentinal tubules. 45 root canals were prepared to ISO 40/04, divided into three groups and irrigated with three protocols: Group 1 (control): 5.25% NaOCl; Group 2: 40% CA (citric acid), 5.25% NaOCl, 40% CA, water, ethanol; Group 3: 40% CA, 5.25% NaOCl, 40% CA, water, 2% chlorhexidine. Canals were filled using vertical condensation technique with gutta-percha and fluorescein-stained AH Plus sealer. After 72 h, 1 mm thick cross-sections were cut at 2, 5, 8 mm from the apex. Confocal laser microscope was used to measure the sealer penetration into dentinal tubules. Mean depth of sealer penetration (in micrometres) was 107, 131, 170 (Group 1); 146, 233, 317 (Group 2); 185, 301, 542 (Group 3); in apical, middle and coronal parts, respectively. Irrigation protocol ended with chlorhexidine resulted in the deeper sealer penetration compared with alcohol.

The effects of alternate irrigation of root canals with chelating agents and sodium hypochlorite on the effectiveness of smear layer removal

BACKGROUND

After the mechanical preparation of a root canal, the canal walls are covered with a smear layer. In order to deeply clean the dentinal tubules, removal of the smear layer is recommended. There is no consensus on the length of time of rinsing with chelating agents or irrigation with alternating chelating agents and sodium hypochlorite (NaOCl).

OBJECTIVES

The aim of the study was to evaluate the effectiveness of smear layer removal using 4 irrigation protocols.

MATERIAL AND METHODS

We prepared 42 straight root canals to size ISO40/04 and assigned them into 4 study groups (n = 10) and a control group (n = 2). The root canals were irrigated as follows: in the control group, 180 s with 5.25% NaOCl; in group 1, 60 s with 40% citric acid (CA) and 120 s with NaOCl; in group 2, 120 s with CA and 120 s with NaOCl; in group 3, 30 s CA, 30 s with NaOCl, 30 s CA and 120 s with NaOCl; and in group 4, 60 s with CA, 30 s with NaOCl, 60 s with CA, and 120 s with NaOCl. The roots were split longitudinally and the root canals were observed under ×200-500 magnification. The root canal walls were analyzed in areas 2 mm, 6 mm and 10 mm from the apex.

RESULTS

In the apical and medial sections, the best effects were achieved in groups 3 and 4. In coronal sections, no significant differences between experimental groups were found.

CONCLUSIONS

Within the limitations of this study, it can be concluded that irrigation with alternating NaOCl and CA was the most effective at smear layer removal, regardless of the irrigation time.

[Necrotizing sialometaplasia--diagnostic difficulties--literature review]

Necrotizing sialometaplasia is a benign, self-limiting inflammatory process, which concerns small salivary glands. This kind of lesion is very rare, with difficulties in clinical and histopathological diagnosis. Ulceration is the dominating symptom, which may suggest that it is a malignancy. Lesions usually heal spontaneously.