Bovine Root Dentin Research Articles

Resin Bonding to Root Canal Dentin: Effect of the Application of an Experimental Hydrophobic Resin Coating after an All-in-one Adhesive

Based on the hypothesis the application of a low-viscosity hydrophobic resin coating improves the bond of all-in-one adhesive, the purpose of the study was to evaluate the bond strength of four adhesive systems to bovine root dentin using the push-out test method. The root canals of 32 bovine roots (16 mm) were prepared to a length of 12 mm using a FRC Postec Plus preparation drill. The specimens were allocated into four groups according to the adhesive system used: (Group 1) All-in-one Xeno III; (Group 2) All-in-one Xeno III+ScotchBond Multi-Purpose Plus Adhesive; (Group 3) Simplified Etch & Rinse One Step Plus; and (Group 4) Multi-Bottle Etch & Rinse All-Bond 2. A fiber-reinforced composite retention post was reproduced using an additional silicon impression and fabricated with DuoLink resin cement. The root specimens were treated with the selected adhesive systems, and the resin posts were luted in the canals with DuoLink resin cement. Each root specimen was cross sectioned into four samples (+/-1.8 mm in thickness), and the post sections were pushed-out to determine the bond strength to dentin. Group 2 (2.9+/-1.2) was statistically higher than Group 1 (1.1+/-0.5) and Group 3 (1.1+/-0.5). Groups 1 and 3 showed no statistically significant difference while Group 4 (2.0+/-0.7) presented similar values (p>0.05) to Groups 1, 2, and 3 [(one-way analysis of variance (ANOVA)] and Tukey test, a=0.05). The hypothesis was accepted since the application of the additional layer of a low-viscosity bonding resin improved the bond of the all-in-one adhesive. Further studies must be conducted to evaluate the long-term bond.

Effects of root dentin surface coating with all-in-one adhesive materials on biofilm adherence

Objectives Sealing of exposed root dentinal surfaces with adhesive materials is expected to be a promising approach for preventing root dentin caries. The aim of this study was to evaluate the effects of surface coating with all-in-one adhesives on inhibiting Streptococcus mutans biofilm attachment. Materials and methods Bovine root dentin was cut and ground with #600-grit SiC paper. Each of the three all-in-one adhesives, Hybrid Bond (HB), Reactmer Bond (RB) or Shake One (SO) was single-coated on the dentin surfaces according to the manufacturers’ instructions. The dentin surface without coating served as the control. The surface roughness of the coated and non-coated dentin surfaces was recorded by means of laser microscope measurements. S. mutans artificial biofilms were then grown on the surface of each specimen in a microcosm for 20 h. The amounts of bacteria and water insoluble glucan in the retained biofilm on the surface of the specimens were measured. All numerical data were statistically analyzed using one-way ANOVA & Tukey's HSD ( p < 0.05). Results All of the coated groups showed significantly lower susceptibility to biofilm attachment compared with the non-coated root dentin ( p < 0.05). Among the coated groups, SO showed the lowest susceptibility for biofilm formation. Conclusions Three all-in-one adhesive materials could be effective for root surface coating. A fluoride-releasing adhesive, SO demonstrated the strongest potentiality in resisting biofilm formation.

Influence of brush type as a carrier of adhesive solutions and paper points as an adhesive-excess remover on the resin bond to root dentin.

To evaluate the influence of the brush type as a carrier of priming adhesive solutions and the use of paper points as a remover of the excess of these solutions on the push-out bond strength of resin cement to bovine root dentin. The null hypotheses were that brush type and the use of paper points do not affect the bond strength. The canals of 80 single-root bovine roots (16 mm in length) were prepared at 12 mm using the preparation drill (FRC Postec Plus, Ivoclar). Half of each root was embedded in acrylic resin and the specimens were divided into 8 groups, considering the factors "brush type" (4 levels) and "paper point" (2 levels) (n = 10): Gr 1: small microbrush (Cavi-Tip, SDI); Gr 2: Microbrush (Dentsply); Gr 3: Endobrush (Bisco); Gr 4: conventional brush (Bisco); Gr 5: Cavi-Tip (SDI) + paper points; Gr 6: Microbrush (Dentsply) + paper points; Gr 7: Endobrush (Bisco) + paper points; Gr 8: conventional brush (Bisco) + paper points. The root dentin was treated with a multistep total-etch adhesive system (All Bond 2). The adhesive system was applied using each microbrush, with and without using paper points. One fiber post was molded with addition silicon and 80 posts were made of resin cement (Duolink). The resin posts were luted (Duolink resin cement), and the specimens were stored for 24 h in water at 37 degrees C. Each specimen was cut into 4 disk-shaped samples (1.8 mm in thickness), which were submitted to the push-out test. The brush type (p < 0.0001) (small microbrush > microbrush = endobrush = conventional brush) and the use of paper points (p = 0.0001) (with > without) influenced the bond strength significantly (two-way ANOVA). The null hypotheses were rejected. The smallest brush (Cavi-Tip) and the use of paper points significantly improved the resin bond to bovine root dentin.

Dentine Remineralisation by Simulated Saliva Formulations with Different Ca and Pi Contents

The understanding of the dentine remineralisation process and the ability to reproduce it in vitro are essential to the development of preventive and therapeutic measures. This study investigated how simulated saliva formulations with different Ca and P_i contents and degrees of saturation with respect to biologically relevant calcium phosphates may affect the remineralisation of eroded dentine, as a function of time. Slabs of bovine root dentine (n = 8 per group) were flattened, polished, demineralised by 1% citric acid for 30 and 60 min and remineralised for 3, 7 and 14 days, by one of the following buffered (pH 7) solutions [Ca:P_i ratio, Ca/P_i concentrations (mM), ionic strength]: solution A: 1.6, 1.5/0.9, 0.115; solution B: 1.6, 2/1.25, 0.117; solution C: 1.6, 3.2/2, 0.121; solution D: 0.3, 1.11/3.7, 0.118; solution E: 0.3, 1.45/5, 0.122. Integrated mineral loss (30 and 60 min) was quantified by transverse microradiography after each remineralisation period. ANOVA and regression analyses (α = 0.05) showed, irrespective of the demineralisation time, that the solutions C and E were able to remineralise dentine. This effect increased throughout the remineralisation times and was significantly higher for E. Remineralisation was successfully shown in vitro, under specific conditions of degree of saturation and Ca and P_i contents of the solutions. Optimum remineralisation was observed for the solution E supersaturated with respect to relevant calcium phosphates, with low Ca:P_i ratio and highest P_i concentration.

Study on the potential inhibition of root dentine wear adjacent to fluoride-containing restorations

The purpose of this in vitro study was to determine whether the vicinity of root dentine that had been restored with fluoride-releasing materials was at reduced risk for erosive/abrasive wear compared to root dentine restored with a non-fluoride-containing material. According to a randomized complete block design, standardized cavities prepared on the surface of 150 bovine root dentine slabs were restored with glass-ionomer cement, resin-modified glass ionomer, polyacid-modified resin composite, fluoride-containing or conventional composite. Specimens were coated with two layers of an acid-resistant nail varnish exposing half of the dentine surface and half of the restoration. Subsequently, specimens were either eroded in an acidic drink or left uneroded, then exposed to artificial saliva and abraded in a toothbrushing machine. Wear depth in the vicinity of restorations was quantified by a stylus profilometer, based on the nonabraded areas surrounding the erosion/abrasion region. Two-way ANOVA did not demonstrate significant interaction between restoratives and eroded-uneroded dentine (p=0.5549) nor significant difference among restorative materials (p=0.8639). Tukey's test ascertained that the wear depth was higher for eroded than for uneroded groups. Fluoride-releasing materials seemed to negligibly inhibit wear in the vicinity of restored root dentine subjected to erosive/abrasive challenges.

Evaluation of the Antifungal Substantivity of Sodium Hypochlorite, Chlorhexidine and MTAD

The purpose of this in vitro study was to compare the antifungal substantivity of 1% MTAD, 2% Chlorhexidine (CHX) and 1.3% sodium hypochlorite (NaOCl) in bovine root dentin. One hundred and ten dentin tubes prepared from bovine incisors were infected in vitro for 72 hours with Candida albicans. The specimens were divided in to five groups as follows: CHX; MTAD; and NaOCl; infected dentin tubes (positive control); and sterile dentin tubes (negative control). Dentin chips were collected with round burs into tryptic soy broth (TSB). After culturing the number of colony-forming units (CFU) was counted. In all experimental groups CFU was minimum in the first cultures, and the results obtained were significantly different from each other at any time period (P<0.05). In first culture, the NaOCI group and CHX group showed the lowest and highest number of CFU, respectively. In each group, the number of CFUs increased significantly by time-lapse (P<0.05). In conclusion, the substantivity of MTAD was significantly greater than CHX and NaOCl.

Evaluation of the antibacterial substantivity of several intra‐canal agents

The aim of this in vitro study was to compare the antimicrobial substantivity of 2% chlorhexidine gluconate (CHX), 100 mg ml(-1) doxycycline and 2.6% sodium hypochlorite (NaOCl) in bovine root dentine. Eighty dentine tubes prepared from bovine incisors were infected in vitro for 14 days with Enterococcus faecalis. The specimens were divided into five groups as follows: doxycycline HCl; CHX; NaOCl; infected dentine tubes (positive control); and sterile dentine tubes (negative control). Dentine chips were collected with round burs into tryptic soy broth. After culturing, the number of colony-forming units (CFU) was counted. In all experimental groups, the number of CFU was minimum in the first cultures, and the results obtained were significantly different from each other at any time period (P < 0.05). In the first culture, the NaOCl group and doxycycline HCl group showed the lowest and highest number of CFU, respectively. In each group, the number of CFU increased significantly by time-lapse (P < 0.05). In conclusion, the substantivity of CHX was significantly greater than NaOCl and doxycycline.

Influence of Fluoride-Releasing Restorative Material on Root Dentine Secondary Caries in situ

The usefulness of fluoride-releasing restorations in secondary caries prevention may be questioned because of the presence of other common sources of fluoride and because of ageing of the restorations. This study tested the hypothesis that glass-ionomer cement restorations, either aged or unaged, do not prevent secondary root caries, when fluoride dentifrice is frequently used. Sixteen volunteers wore palatal appliances in two phases of 14 days, according to a 2 × 2 crossover design. In each phase the appliance was loaded with bovine root dentine slabs restored with either glass-ionomer or resin composite, either aged or unaged. Specimens were exposed to cariogenic challenge 4 times/day and to fluoridated dentifrice 3 times/day. The fluoride content in the biofilm (FB) formed on slabs and the mineral loss (ΔZ) around the restorations were analysed. No differences were found between restorative materials regarding the FB and the ΔZ, for either aged (p = 0.792 and p = 0.645, respectively) or unaged (p = 1.00 and p = 0.278, respectively) groups. Under the cariogenic and fluoride dentifrice exposure conditions of this study, the glass-ionomer restoration, either aged or unaged, did not provide additional protection against secondary root caries.

Hybrid layer seals the cementum/4‐META/MMA‐TBB resin interface

Although 4-META/MMA-TBB resin has adhesive properties to dentin, and has been clinically used for the bonding treatment of vertically fractured roots and apicoectomy, there has not been any investigation on the adhesion of 4-META/MMA-TBB resin to cementum. The purpose of this in vitro study was to evaluate the bonding and the sealing ability of 4-META/MMA-TBB resin to cementum. Bovine root cementum and dentin surfaces were treated with a citric acid and ferric chloride solution, and the 4-META/MMA-TBB resin was applied on the treated surfaces before testing. The microtensile bond strength and the leakage levels obtained for the cementum were almost equal to those for the dentin. In SEM and TEM observations, a hybrid layer approximately 2-3 microm in thickness was observed at the interface between the resin and the cementum. It is concluded that 4-META/MMA-TBB resin adhered to cementum via a hybrid layer on cementum, as previously reported for dentin.

The role of Carisolv™ and different auxiliary chemical substances in the removal of bovine root canal smear layer

To evaluate the effectiveness of Carisolv and different auxiliary chemical substances in root canal smear layer (SL) removal. SL was produced in the centre of 40 hemi-disks of bovine root dentine. The samples were divided into four irrigation groups (G): GI (control) - 0.9% NaCl; GII - 1% NaOCl + 0.9% NaCl; GIII - Carisolv + 0.9% NaCl; GIV - 1% NaOCl + 10% citric acid solution + 0.9% NaCl. The photomicrographs (SEM analysis) were coded (0 - absence of SL; 1 - moderate SL; 2 - dense SL with visible tubules; 3 - dense SL with no visible tubules). GIV was more effective in SL removal (P < 0.01). It should be noted that GI and GIII obtained score 3 in 100% of the samples (P > 0.01). NaOHCl, citric acid and NaCl solutions, when used together, presented a better performance in the removal of SL when compared to the other solutions.

Fluoride release and secondary caries inhibition by adhesive systems on root dentine

This study tested the fluoride-release rate and the root caries inhibitory effect of dental adhesives. In phase 1, the fluoride released from samples (n = 5) of the adhesives A (Optibond Solo), B (One-up Bond F), C (Prime & Bond NT), D (Tenure Quick), and also of the controls [+] (glass-ionomer cement) and [-] (non-fluoride releasing adhesive), was quantified on a daily basis during a pH-cycling, caries-simulating phenomenon. In phase 2, restorations were made in bovine root dentine slabs (n = 16) with the same adhesives associated with a non-fluoridated composite. Control [+] restorations were made entirely with glass-ionomer cement. Specimens were thermocycled and submitted to the pH-cycling regimen. Demineralization areas and the presence of the wall lesion (WL) and the inhibition zone (IZ) were determined by polarizing light microscopy in dentine adjacent to the restoration. The highest concentration of fluoride was released by the control [+]; adhesives A, B and C, also released fluoride. No detectable amount of fluoride was released by D or [-]. Smaller areas of demineralization were found with control [+], whereas the demineralization areas of adhesives A-D and [-] did not differ from each other. No WL was detected, and higher percentages of IZ were recorded to [+] and to adhesive A. Although some dental adhesives were able to release fluoride, they could not inhibit secondary caries development as well as the glass-ionomer cement.

Antibacterial efficacy of calcium hydroxide, iodine potassium iodide, betadine, and betadine scrub with and without surfactant against E faecalis in vitro

This study investigated the ability of endodontic irrigants and medicaments to eliminate Enterococcus faecalis from infected dentinal tubules, and whether their antimicrobial action was enhanced by surfactant. For the study, 5-mm dentin disks were sectioned from bovine incisor roots and infected with E faecalis. Lumens were instrumented, and 1 of 7 medicaments (10% Ca(OH) 2, Betadine, or IKI, each with or without surfactant, or Betadine Scrub) was used to flush and fill each lumen. Positive controls received saline. Specimens were incubated for 15 minutes or 24 hours. Quantitative microbiology of the remaining bacteria was performed and groups were compared using a 1-way ANOVA. The addition of surfactant did not enhance the antibacterial action of any medicament. When used as a 24-hour medicament, Ca(OH) 2 consistently failed to eliminate E faecalis, whereas both Betadine Scrub and IKI rendered 90% of samples sterile. IKI was the only agent shown to consistently eliminate E faecalis in a 15-minute time frame. Under the in vitro conditions of this study, IKI was able to eliminate E faecalis from bovine root dentin when used with a 15-minute contact time.

Abrasion of eroded root dentine brushed with different toothpastes.

This study evaluated the surface roughness change and wear provided by different dentifrices on root dentine previously exposed to erosive challenges. According to a randomized complete block design, 150 slabs of bovine root dentine (6 x 3 x 2 mm) were ground flat and polished. In an area of 4 x 3 mm on the dentine surface, specimens were submitted to five erosive/abrasive events, each one composed by: exposure to Sprite Diet or distilled water for 5 min, then to a remineralizing solution for 1 min, and simulation of 5,000 brushing strokes. Four dentifrices--regular (RE), baking soda (BS), whitening (WT) and tartar control (TC)--and distilled water (CO), used as control, were compared. Final texture and the wear depth were evaluated using a profilometer. ANOVA did not show significant interaction, indicating that the effect of dentifrices on both surface roughness change and wear did not depend on whether or not the dentine was eroded ( p>0.05). There was no difference between abrasion of eroded and sound dentine. The Tukey's test revealed that WT, BS and TC provided the highest increase in surface roughness differing from RE and CO. TC yielded the deepest wear of root dentine, whereas RE and CO, the shallowest. No significant difference in wear among BS, TC and WT were observed. Within the limitations of this study, the data showed that abrasion of both eroded and sound root dentine was dependent on the dentifrice used.

Bactericidal effect of a 980-nm diode laser in the root canal wall dentin of bovine teeth.

The aim of this in vitro study was to investigate the antibacterial depth effect of continuous wave laser irradiation with a wavelength of 980 nm in the root canal wall dentin of bovine teeth. The long-term success of an endodontic therapy often fails due to remaining bacteria in the root canal or dentin tubules, which cannot be sufficiently eliminated through the classical root canal preparation technique nor through rinsing solutions. A total of 102 slices of bovine root dentin of different thicknesses (100, 300 and 500 micro m) were prepared. The samples were inoculated from one side with 5 micro L of an enterococcus faecalis suspension of defined concentration. Four slices per slice thickness served as a control group; the rest of the 30 slices per thickness were subjected to laser irradiation - 10 each of these slices were irradiated with distal outputs of 1.75, 2.3, and 2.8 Watts (W). After drying them for 30 sec, the back of the inoculated dentin slice was irradiated for 32 seconds with a 200- micro m fiber optical waveguide under constant movement of the fibers. The remaining bacteria were then detached in NaCl under vibration. The eluate produced by this was - taking account of the degree of dilution - plated out on sheep blood agar plates. After 24 h of incubation, the grown bacterial colonies were able to be counted out and evaluated. By doing so, they were compared with the non-irradiated, but otherwise identically treated control group. With a slice thickness of 100 micro m, the 980-nm diode laser achieved a maximum bacterial reduction of 95% at 1.75 W, 96% at 2.3 W, and 97% at 2.8 W. With a slice thickness of 300 micro m, a maximum of 77% of the bacteria was destroyed at 1.75 W, 87% at 2.3 W, and 89% at 2.8 W. The maximum bacterial reduction with a slice thickness of 500 micro m was 57% at 1.75 W, 66% at 2.3 W, and 86% at 2.8 W. The results of this research show that the 980-nm diode laser can eliminate bacteria that have immigrated deep into the dentin, thus being able to increase the success rate in endodontic therapy.

Durability of Adhesion between 4-META/MMA-TBB Resin and Cementum

4-META/MMA-TBB resin has shown good biocompatibility and remarkable adhesion to dentin. It seems to be suitable for use in periodontal tissues for retrograde root sealing and treatment of vertically fractured roots. For an adhesive resin to be useful clinically, it must bond not only to the dentin but also to the cementum. The purpose of this study was to evaluate the long-term adhesion durability of 4-META/MMA-TBB resin to cementum kept in water at 37 degrees C. Bovine root cementum and dentin surfaces were treated with 10-3 solution before 4-META/MMA-TBB resin was applied on treated surfaces. The micro-tensile bond strength (microTBS) decreased during the first two months; dye leakage value increased during the first four months and stabilized thereafter. No significant differences in adhesion durability were recognized between the dentin and cementum.

Caries Progression and Inhibition in Human and Bovine Root Dentine in situ

Since the use of bovine instead of human dentine to evaluate cariogenic and anticariogenic substances is not well established, this in situ study was conducted. Eleven volunteers wore palatal acrylic devices containing 4 dentine slabs (2 human and 2 bovine). Sucrose solution (20%) was dripped over all slabs 4 times a day, simulating a cariogenic challenge. Dentifrice slurries, fluoridated or not, were dripped over specified dentine slabs 3 times a day to evaluate caries reduction. After 14 days, the biofilm formed on the dentine slabs was collected for microbiological analysis. In dentine, mineral loss (ΔZ) and lesion depth (LD) were determined by cross-sectional microhardness and by polarized light microscopy, respectively. The total streptococci and mutans streptococci counts in the biofilm formed either on human or on bovine slabs, whether treated or not with fluoride dentifrice, were not statistically different. The ΔZ and the LD values of dentine treated with fluoride dentifrice were significantly lower than the values of dentine treated with non-fluoride dentifrice. The differences in the ΔZ and LD values between the human and bovine dentine were not statistically significant. The results suggest that bovine dentine can be used instead of human to evaluate caries development and inhibition.

Effect of a Lactose-Containing Sweetener on Root Dentine Demineralization in situ

Since lactose has been used as an excipient in powdered sweeteners, we evaluated its effect on dentine demineralization, in an in situ crossover study. Twelve adult volunteers wore palatal appliances containing 4 blocks of bovine root dentine, which were submitted 4 times a day to: distilled water (negative control), aqueous solution of powdered sweetener (Zero Cal^®; experimental group), 1.5% lactose solution (active group), 1.5% sucrose solution (positive control). After 15 days, microhardness was determined on dentine surface (SMH) and on the sectioned blocks (CSMH). All groups presented statistical differences in SMH before and after the treatments; water increased, while sweetener, lactose and sucrose decreased SMH. By CSMH, the only significant difference was observed after sucrose treatment. The data suggest that sweeteners containing lactose as a bulking agent may be cariogenic for root dentine.

Effect of tubule orientation and dentin location on the microtensile strength of bovine root dentin.

To investigate the mechanical properties of root dentin and to further clarify the cause of vertical root fracture (VRF), this study evaluated the effect of tubule orientation (parallel, perpendicular and oblique to the cross-section of dumbbell specimens in microtensile tests) and dentin location (cervical, middle, and apical location of the root) on the microtensile strength of bovine root dentin. Each specimen was stressed in tension at a crosshead speed of 1.0 mm/min. The results of the microtensile strength measurements were statistically analyzed with one-way ANOVA and the Fisher PLSD. The oblique group (95.18+/-23.80 MPa) was significantly (p<0.01) higher than the parallel group (38.93+/-5.28 MPa) or the perpendicular group (32.64+/-4.69 MPa). There were no significant differences among the different dentin locations within the parallel group (p>0.05). It was clarified that the VRF occurs frequently in practical situations due to the tubule orientation of root dentin.

Antimicrobial Substantivity of Bovine Root Dentin Exposed to Different Chlorhexidine Delivery Vehicles

Root canal dentin acquires antimicrobial substantivity after exposure to chlorhexidine gluconate (CHX) for 1 wk. Therefore development of a vehicle for delivery of CHX as an intracanal medication is desirable. This in vitro study assessed the efficacy of two CHX delivery vehicles, a controlled-release device and a gel, to affect antimicrobial substantivity of bovine root dentin. Sixty bovine incisor root specimens were prepared with standardized length (10 mm) and canal diameter (3.3 mm), and coated externally with nail polish. Specimens were divided into four equal groups and their canals medicated for 7 days with either: (i) an experimental controlled-release device containing 25% CHX that was immersed in sterile saline; (ii) 2% CHX gel; or (iii) Ca(OH)2 paste. Sterile saline was used as the positive control. After medication, the canals of the specimens were inoculated with Enterococcus faecalis for 21 days. Root canal dentin samples ranging in depth from 0.1 to 0.45 mm were then obtained using sterile round burs of ascending diameter. Each dentin sample was placed in a separate test tube containing Brain Heart Infusion broth and incubated for 24 h. The optical density (OD) of the broth was then measured spectrophotometrically at 540 nm. The positive control showed significantly higher mean OD values (one-way ANOVA and Tukey's Studentized Range Test; p < 0.001) than the three test groups. The CHX controlled-release device group showed significantly lower OD values than the Ca(OH)2 group; however only at dentin depths up to 0.2 mm. In contrast, the CHX gel group consistently showed significantly lower OD values than both the CHX controlled-release device and Ca(OH)2 groups. These results suggest that bovine root canals medicated with 2% CHX gel for 7 days acquire antimicrobial properties for at least 21 days.

Antimicrobial Substantivity of Chlorhexidine-Treated Bovine Root Dentin

Previous studies have demonstrated antimicrobial substantivity in root canal dentin up to 7 days after treatment with chlorhexidine. This in vitro study assessed the antimicrobial substantivity of chlorhexidine-treated bovine root dentin over a period of 21 days. Sixty standardized bovine root sections were randomly divided into three equal groups, and their canals immersed in one of the following solutions: (i) sterile saline; (ii) 2.5% NaOCl; or (iii) 0.2% chlorhexidine (CHX). Half the specimens in each group were treated with the solution for 5 min and the other half for 7 days. After solutions were removed, the specimens were incubated at 37 degrees C in Brain Heart Infusion broth containing Enterococcus faecalis (ATCC 29212). A fresh inoculum was added to the broth every other day over a 21-day period. The canals were then enlarged with sterile burs, and the dentin shavings collected and cultured for the presence of cultivable bacteria in the dentinal tubules. Specimens treated with CHX for 7 days demonstrated significantly less dentin colonization by E. faecalis than the other specimens. CHX has potential as an intracanal medicament, if it can be applied for a period of at least 7 days.