Effect of calcium hydroxide on inflammatory root resorption and ankylosis in replanted teeth compared with other intracanal materials: a review

Calcium hydroxide (CH) is the gold-standard intracanal dressing for teeth subjected to traumatic avulsion. A common complication after the replantation of avulsed teeth is root resorption (RR). The current review was conducted to compare the effect of CH with that of other intracanal medications and filling materials on inflammatory RR and replacement RR (ankylosis) in replanted teeth. The PubMed and Scopus databases were searched through June 2018 using specific keywords related to the title of the present article. The materials that were compared to CH were in 2 categories: 1) mineral trioxide aggregate (MTA) and endodontic sealers as permanent filling materials for single-visit treatment, and 2) Ledermix, bisphosphonates, acetazolamide, indomethacin, gallium nitrate, and enamel matrix-derived protein (Emdogain) as intracanal medicaments for multiple-visit management of avulsed teeth prior to the final obturation. MTA can be used as a single-visit root filling material; however, there are limited data on its efficacy due to a lack of clinical trials. Ledermix and acetazolamide were comparable to CH in reducing RR. Emdogain seems to be an interesting material, but the data supporting its use as an intracanal medication remain very limited. The conclusions drawn in this study were limited by the insufficiency of clinical trials.

Comparison of endodontic medicaments on bond strength of fiber post to root dentin using resin cement

Statement of the Problem: Endodontic irrigants and medicaments may affect the bond strength of intracanal posts to root dentin

Purpose: The aim of this study was to compare the effect of calcium hydroxide [Ca[OH][2]] and 2% chlorhexidine gel [CHX] on bond strength of fiber post cemented with resin cement to root dentin

Materials and Method: This in vitro experimental study was conducted on 36 mandibular premolars. Canals were prepared using the step back technique. After root canal irrigation, the teeth were divided into three groups of 12. Ca[OH][2] paste and CHX gel were used as intracanal medicaments in the first and second groups respectively. No intracanal medicament was used in the third group [control group]. Access cavities were then sealed and the teeth were incubated for one week. The root canals were then filled using gutta percha and AH26 sealer and the teeth were incubated for 72 hours. Tooth crowns were then cut at the level of the cementoenamel junction and intracanal posts were placed. The teeth were mounted in auto-polymerizing acrylic resin, and incubated for one week .They were then sectioned into 1.5mm thick slices from their coronal surface using a fully automated cutting machine, and subjected to push-out test until failure. The load at debonding was recorded and data were analyzed using one-way ANOVA, post-hoc test and t-test. The coronal margin of the root was at the level of the surface of acrylic resin in the mold

Results: The mean bond strength was 4.45 MPa in the Ca[OH][2], 2.45 MPa in the CHX and 2.48 MPa in the control group. The difference in this regard was statistically significant among groups [p= 0.04]. The Ca[OH][2] group had significant differences with the CHX and control groups [p= 0.03 and p= 0.02, respectively]. The difference between the CHX and control groups was not significant [p= 0.974]

Conclusion: Based on the results, Ca[OH][2] increased the bond strength of fiber post to root dentin but 2% CHX had no effect on bond strength

Effect of triple antibiotic paste and calcium hydroxide as intracanal medicaments on bond strength of composite to dentin

Objective: Considering the use of triple antibiotic paste [TAP] for root canal treatment of open apex teeth, this study aimed to assess the effect of TAP and calcium hydroxide [CH] on bond strength of composite to dentin

Methods: This in-vitro study was conducted on 32 extracted human premolar teeth. After disinfection with 2% thymol solution, the enamel on the buccal surface of specimens was removed to expose a smooth dentin surface parallel to the long axis of the teeth with approximately 19mm2 surface areas. Specimens were divided into three groups of 11, 10 and 11 specimens. In group one, TAP, in group two CH and in group three, saline solution were applied to dentin surfaces for 14 days. After removal of medicaments, composite cylinders were bonded to the dentin surfaces using a bonding agent. Shear bond strength was measured in an Instron machine at a crosshead speed of 1mm/min. Data were analyzed using one-way ANOVA

Results: The highest mean bond strength belonged to the control group [14.4760 MPa] and the lowest belonged to the TAP group [11.5808 MPa]. The mean bond strength in CH group was less than that of the control and higher than that of the TAP group [11.7834 MPa]. However, the difference among the three groups was not statistically significant [p=0.327]

Conclusion: Use of medicaments such as CH and TAP has no effect on bond strength of composite to dentin

Cytotoxicity of triple antibiotic paste and calcium hydroxide against cultured human dental pulp fibroblasts

Objective: In necrotic immature teeth, intra canal medicaments such as triple antibiotic paste [TAP] and calcium hydroxide [CH] are used for root canal disinfection and regeneration treatment. However, the effect of these medicaments on dental pulp fibroblasts has yet to be known. This study aimed to assess the cytotoxicity of CH and TAP against cultured human dental pulp fibroblasts [HDPFs] obtained from third molars

Methods: In this in vitro study, fibroblasts were obtained from the dental pulp of two third molars. Fibroblasts were exposed to 0.1, 1 and 10 mg/mL concentrations of TAP and CH. Six samples were prepared of each medicament and fibroblast viability was evaluated after 72 hours. Data were analyzed using one-way and two-way ANOVA [p<0.001]. The percentage of cell viability was calculated and the cytotoxicity of the medicament was categorized as severe [30%], moderate [30- 60%], mild [60-90%] and non-toxic [>90%]

Results: In TAP samples, only the 10 mg/mL concentration had a significant difference with the control group in terms of the percentage of cell viability and showed moderate cytotoxicity. In CH samples, the 1 and 10 mg/mL concentrations showed significant differences with the control group and were severely cytotoxic

Conclusion: Reduction in cell viability of fibroblasts by increase in concentration was significantly greater in CH compared to TAP group. Thus, in regeneration treatments, these medicaments must be used in concentrations with adequate therapeutic and insignificant adverse effects on fibroblasts

Effects of endodontic tri-antibiotic paste on bond strengths of dentin adhesives to coronal dentin

OBJECTIVES: The aim of this study was to evaluate the effects of tri-antibiotic paste (TAP) on microtensile bond strengths (MTBS) of dental adhesives to dentin. MATERIALS AND METHODS: Sixty extracted molars had their occlusal surfaces flattened to expose dentin. They were divided into two groups, i.e., control group with no dentin treatment and experimental group with dentin treatment with TAP. After 10 days, specimens were bonded using self-etch (Filtek P90 adhesive) or etch-and-rinse (Adper Single Bond Plus) adhesives and restored with composite resin. Teeth were sectioned into beams, and the specimens were subjected to MTBS test. Data were analyzed using two-way ANOVA and post hoc Tukey tests. RESULTS: There was a statistically significant interaction between dentin treatment and adhesive on MTBS to coronal dentin (p = 0.003). Despite a trend towards worse MTBS being noticed in the experimental groups, TAP application showed no significant effect on MTBS (p = 0.064). CONCLUSIONS: The etch-and-rinse adhesive Adper Single Bond Plus presented higher mean bond strengths than the self-etch adhesive Filtek P90, irrespective of the group. The superior bond performance for Adper Single Bond when compared to Filtek P90 adhesive was confirmed by a fewer number of adhesive failures. The influence of TAP in bond strength is insignificant.

Effects of endodontic tri-antibiotic paste on bond strengths of dentin adhesives to coronal dentin

OBJECTIVES: The aim of this study was to evaluate the effects of tri-antibiotic paste (TAP) on microtensile bond strengths (MTBS) of dental adhesives to dentin. MATERIALS AND METHODS: Sixty extracted molars had their occlusal surfaces flattened to expose dentin. They were divided into two groups, i.e., control group with no dentin treatment and experimental group with dentin treatment with TAP. After 10 days, specimens were bonded using self-etch (Filtek P90 adhesive) or etch-and-rinse (Adper Single Bond Plus) adhesives and restored with composite resin. Teeth were sectioned into beams, and the specimens were subjected to MTBS test. Data were analyzed using two-way ANOVA and post hoc Tukey tests. RESULTS: There was a statistically significant interaction between dentin treatment and adhesive on MTBS to coronal dentin (p = 0.003). Despite a trend towards worse MTBS being noticed in the experimental groups, TAP application showed no significant effect on MTBS (p = 0.064). CONCLUSIONS: The etch-and-rinse adhesive Adper Single Bond Plus presented higher mean bond strengths than the self-etch adhesive Filtek P90, irrespective of the group. The superior bond performance for Adper Single Bond when compared to Filtek P90 adhesive was confirmed by a fewer number of adhesive failures. The influence of TAP in bond strength is insignificant.

Fracture strength of mesiobuccal roots following canal preparation with hand and rotary instrumentation: an in vitro study

The aim of this in vitro study was to compare the effect of hand and rotary instruments on fracture strength of tooth roots. Thirty two teeth were randomly divided into two experimental groups of 15 each and one negative control group with two samples. In group 1, step-back technique with conventional stainless steel K-files was used, and in group 2, instrumentation was performed using rotary Ni-Ti Hero642. Samples in control group did not receive cleaning or shaping after access cavity preparation. After obturating each canal, tip of the spreader was locked within canal. The required force for root fracture was measured using Instron testing machine. Recorded data was statistically analyzed using t-test. The mean and standard deviation force required for vertical root fracture were 50.33 +/- 19.1 and 63.1 +/- 25.46 N for hand and rotary groups respectively. However, no significant difference was found between experimental groups. The results indicate that the manual technique did not lower fracture strength of obturated roots in comparison with the rotary preparation technique

Comparing coronal discoloration between AH26 and ZOE sealers

Intrinsic tooth discolorations after endodontic treatment are principally attributed to the composition of necrotic pulp tissue, hemorrhage within the pulp cavity, endodontic medicaments and/or filling materials. Residual sealer left in pulp chamber after obturation can cause discoloration. The objective of this in vitro study was to evaluate coronal discoloration created by AH26 and ZOE sealers after four months. Fifty intact human extracted maxillary central incisors were employed. Access cavities were prepared in all samples and root canals were instrumented; coronal orifices were then sealed using self-cure glass ionomer. The teeth were divided into two experimental groups [n=20] according to utilized sealer in pulp chambers including AH26 and Dorifill [ZOE]. The remaining 10 teeth served as negative and positive controls [n=5]. The access cavities were sealed with self-cure glass ionomer. Teeth were kept in incubator for four month. Preliminary digital images of the teeth were taken and then compared with those related to 4-month follow-up. The images were assessed using Photoshop software. Data was analyzed using paired t-test and independent samples t-test. The teeth which were filled with AH26 sealer showed significantly greater discoloration than those filled with ZOE sealer [Dorifill] [P<0.05]. AH26 sealer causes greater discoloration of the crown compared to ZOE sealer. Despite the other disadvantage of AH26 sealer, it seems that Dorifill is more esthetically considerate

effect of three irrigants on the coronal leakage of the root canals system irrigants

The production of smear layer during canal instrumentation is thought to increase coronal microleakage even after canal obturation. Previous studies have shown that the type of irrigant does not necessarily affect the seal of the obturation. Our study aimed to evaluate the effect of three irrigation solutions [MTAD, citric acid and EDTA/NaOCl] on the coronal microleakage of root canals. Fifty five intact single rooted teeth were instrumented and randomly divided into three experimental groups [15 teeth each] and two control groups [5 teeth each]. Final irrigation was carried out with MTAD in group I, citric acid in group II, and EDTA/NaOCl in group III. EDTA/NaOCl was used for the negative control group and saline irrigation was carried out in the positive control group. After lateral compaction with gutta-percha, the access cavities of the experimental specimens were restored with temporary restorative material. Temporary cement was not used in the positive control group. In the negative control group, access cavities and foramen apices were sealed with glass ionomer. Microleakage of samples was measured using the dye penetration technique. Data were analyzed with ANOVA and Tukey test to determine statistical differences between groups. MTAD, citric acid and EDTA/NaOCl all had less microleakage compared to normal saline. However, no difference was detected between the experimental groups. In this study, all three groups demonstrated effective seal with gutta-percha obturation. This is likely to be due to various factors including their ability to remove smear layer