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The solubility in water and 37% phosphoric acid, and compressive strength of four brands of hard-setting calcium hydroxide base materials were studied. Results were highly variable among brands and no correlations appeared to exist between properties studied. One product was significantly different from the others with regard to acid solubility and compressive strength.
AIM: To compare histological responses to zinc oxide-eugenol (ZOE) and calcium hydroxide (CH) pulpectomies in primary molar teeth with inflamed pulps. STUDY DESIGN: This was an experimental study in 17 juvenile baboons (Papio ursinus). METHODS: Pulpitis was induced with fresh human carious dentine or Streptococcus mutans placed into occlusal cavities in 78 primary molars; after 14 days a pulpectomy was performed on the same primary molars with the two root fillings randomly allocated. The root canal openings were then covered with IRM and the cavity filled with amalgam. After 90 days specimens were harvested and examined under the light microscope with the examiner blind to the treatment. RESULTS: Reaction frequencies in the ZOE-treated versus CH-treated teeth were: no recognisable pulp 89% and 82%, internal root resorption 0% and 1%, external root resorption 11% and 24%, presence of bacteria 5% and 18%, periapical abscesses 24% and 52%. STATISTICS: Fisher's exact probability test showed a statistically significant higher prevalence of periapical abscesses in the CH-treated group (P=0.03, relative risk 2.2). CONCLUSIONS: ZOE pulpectomy is preferred to CH for the treatment of infected pulps in primary molars.
The aim of this study was to investigate whether differences in the composition of calcium hydroxide (Ca(OH)2) preparations influence the removal efficiency of irrigation solutions used in combination with filing of the canal. Three Ca(OH)2 preparations were used: Calxyl, Pulpdent paste, and chemically pure Ca(OH)2 mixed with distilled water. Fifty-one single-rooted extracted human teeth were prepared with a step-back technique and divided into groups A, B, and C. In each group, 15 teeth were assigned to each Ca(OH)2 preparation while the remaining two served as positive and negative controls. Each group of treated teeth was divided into three subgroups of five teeth each: subgroup I--canals were irrigated with saline, filed with a #25 file, and finally flushed with saline; subgroup II--canals were irrigated with NaOCl, filed with a #25 file, and finally flushed with NaOCl; and subgroup III--canals were irrigated with NaOCl, filed with a #25 file, and finally flushed with tetrasodium EDTA. Canal sections were then photographed, and the percentage ratios of Ca(OH)2 coated area to the total canal surface area were calculated by image processing analysis. Results revealed: (a) none of the methods efficiently removed all dressing from the walls, and (b) concentration of the paste used had little effect on the efficacy of the methods applied for the removal of the dressing. Excipients (i.e. methylcellulose contained in Pulpdent) possibly effect retention of Ca(OH)2.
AIM: To determine in vitro the time required for recontamination of coronally sealed canals medicated with either calcium hydroxide (CaOH2), 2% chlorhexidine gel (CG) or with a combination of both. METHODOLOGY: Eighty intact, caries-free, premolar teeth with straight roots and mature apices were selected for the study. After biomechanical preparation of 75 teeth, they were randomly divided into nine groups according to the intracanal medicament and the coronal seal with 'Intermediate Restorative Material' (IRM) as follows: (i) 10 teeth medicated with CG, coronally unsealed; (ii) 10 teeth medicated with CaOH2, coronally unsealed; (iii) 10 teeth medicated with CaOH2 + CG, coronally unsealed; (iv) 10 teeth medicated with CG + coronal seal; (v) 10 teeth medicated with CaOH2 + coronal seal; (vi) 10 teeth medicated with CG + CaOH2 + coronal seal; (vii) 10 teeth without intracanal medicament and coronally sealed; (viii) 5 teeth without intracanal medicament and coronally unsealed, used as the positive control group (PC); (ix) 5 teeth with intact crowns used as the negative control group (NC). Glass flasks were filled with Brain Heart Infusion broth (BHI), so that only the root apex was in contact with the broth, while the crown was immersed in human saliva + BHI (3:1). The flasks were then incubated at 37 degrees C in an atmosphere of 10% CO2, and microbial growth was checked daily. RESULTS: All specimens of the PC showed contamination within 1 day of incubation, while the NC showed no evidence of broth turbidity. Recontamination was detected after an average time of 3.7 days in the unsealed canals medicated with CG, 1.8 days in the group medicated with CaOH2 and 2.6 days in the group medicated with CaOH2 + CG. When the crowns were sealed with IRM, recontamination was detected within 13.5 days in the canals medicated with CG, after 17.2 days in the group medicated with CaOH2 and after 11.9 days in the group medicated with CG + CaOH2. The group with no medication, but sealed with IRM, showed recontamination after 8.7 days. There were statistically significant differences between the teeth with or without coronal seal (P<0.05). CONCLUSION: The coronal seal delayed but did not prevent leakage of microorganisms. There was no difference between the various medicaments.
The purpose of this study was to evaluate the influence of calcium hydroxide (Ca(OH)2) treatment on the bond strengths to dentin of a resin-based composite material. Two distinct dental adhesives, Prime & Bond (P&B) NT and Single Bond (SB) were used. One hundred and twenty-seven bovine incisors were mounted in acrylic, ground flat to expose middle dentin, polished to 600-grit, and randomly assigned to 10 groups: (i) 0 days, no Ca(OH)2, P&B NT; (ii) 7 days, no Ca(OH)2, P&B NT; (iii) 7 days, Ca(OH)2, P&B NT; (iv) 30 days, no Ca(OH)2, P&B NT; (v) 30 days, Ca(OH)2, P&B NT; (vi) 0 days, no Ca(OH)2, SB; (vii) 7 days, no Ca(OH)2, SB; (viii) 7 days, Ca(OH)2, SB; (ix) 30 days, no Ca(OH)2, SB; (x) 30 days, Ca(OH)2, SB. All specimens were stored in an incubator at 37 degrees C. Specimens were then retrieved and the dentin surface was rinsed with air/water spray from a triple syringe. Dentin was etched with 37% phosphoric acid (PA) for 15 s, rinsed, blot dried, and coated with adhesive according to manufacturer's instructions. The adhesive was light cured for 10 s, and Filtek Z250 was applied to the surface with a #5 gelatin capsule and light cured for 160 s. Shear bond strengths were measured for each specimen in an Instron unit at a cross-head speed of 0.5 mm min(-1). The data were subjected to anova and Duncan post-hoc tests. Mean shear bond strengths for P&B NT ranged from 8.02 to 11.79 MPa. There was no significant difference between P&B NT groups treated with or without Ca(OH)2 at any time interval. Mean shear bond strengths for SB ranged from 14.70 to 19.54 MPa. No significant difference was found between SB groups treated with or without Ca(OH)2 at 7 days. At 30 days, SB with Ca(OH)2 was significantly higher than SB without Ca(OH)2. Short-term Ca(OH)2 treatment had no detrimental effect on dentin bond strengths to the ethanol or acetone-based adhesive resin systems tested.
Root canals of dog premolar teeth with or without debris were filled with calcium hydroxide with or without pressure. The histologic results, 90 days after treatment, showed better results in the specimens without debris. More favorable results were obtained with the pressure filling when debris was present in small amounts.
The antibacterial activities of camphorated paramonochlorophenol, chlorhexidine, and calcium hydroxide were compared using a clinical and laboratory evaluation. In the clinical experiment, root canals that yielded positive cultures a week after complete chemomechanical preparation and camphorated paramonochlorophenol dressing were medicated with one of the three substances tested. Postmedication samples were taken from the canal 1 week later. In the laboratory experiment, the agar diffusion test was used to evaluate the inhibitory activity of the medicaments against bacteria commonly found in endodontic infections. The results of the clinical evaluation showed that all medicaments were effective in reducing or eliminating the endodontic microbiota, as demonstrated by the incidence of negative cultures. There was no statistically significant difference among the medicaments tested. In the laboratory evaluation, camphorated paramonochlorophenol showed the largest zones of bacterial inhibition against all bacterial strains tested.
Histological characteristics and bone morphogenetic protein-2 (BMP-2) expression were evaluated in apexification procedures using calcium hydroxide [Ca (OH)2] and mineral trioxide aggregate (MTA). In three of four quadrants of the mouth, monkey (Macaca fascicularis) teeth were infected by pulpal exposure to saliva. After 90 days, each group was treated with Ca (OH)2 or MTA. Infected, untreated teeth were used as negative controls and normally developing teeth were used as positive controls. Areas within the apical region of each sample were scored based upon histological findings and BMP-2 expression. Overall, BMP-2 expression in all areas was similar in the Ca (OH)2, MTA, and infection/no treatment groups, which tended to be more immunoreactive for BMP-2 than the untreated group. Use of MTA in combination with Ca (OH)2 may initiate regeneration of the periodontium more quickly than either material used alone, but further studies involving MTA use in apical closure are indicated.
The aim of this study was to investigate the antimicrobial activity of calcium hydroxide (Ca(OH)2) combined with 2% chlorhexidine gluconate (CHX) gel against endodontic pathogens and to compare the results with the ones achieved by Ca(OH)2 mixed with sterile water and by CHX gel alone. Two methods were used: the agar diffusion test and the direct contact test. Ca(OH)2 + 2% CHX gel produced inhibitory zones ranging from 2.84 to 6.5 mm, and required from 30 seconds to 6 hours to eliminate all tested microorganisms. However, 2% CHX gel showed the largest microbial growth zones from 4.33 to 21.67 mm, and required 1 minute or less to inhibit all tested microorganisms. A paste of Ca(OH)2 plus sterile water inhibited only the microorganisms with which it was in direct contact and required from 30 seconds to 24 hours to kill all tested microorganisms. In conclusion, 2% CHX gel + Ca(OH)2 showed better antimicrobial activity than Ca(OH)2 manipulated with sterile water.
The effect of time of the onset of calcium hydroxide (CH) pulpectomy on root resorption of 31 permanent dog incisors was investigated. CH pulpectomy was delayed 4, 9, 14 and 18 days after the teeth were extracted and replanted. Control teeth were replanted 1) without pulpectomy, 2) with a pulpectomy only or 3) with a pulpectomy and CH filling. All teeth were prepared for histologic evaluation 8 weeks after the teeth were replanted. Cross section were examined using a computer microscope and linear (micron) and/or square areas (micron 2) of surface (SRR), inflammatory (IRR), and replacement (RRR) root resorption were calculated. From this data the percentage of linear and area resorption was averaged for each group. Duncan multiple range t-test (P < or = 0.05) revealed that teeth in which a pulpectomy with CH filling was done extraorally had significantly greater SRR than the rest of the groups; teeth in which a pulpectomy without CH filling was done extraorally had significantly greater RRR than teeth in which CH pulpectomy was delayed for 18 days; there was no significant difference in SRR, IRR or RRR when CH placement was delayed 4, 9, 14 or 18 days after replantation. Although it was not significant the overall resorption was least when CH pulpectomy was delayed 18 days.
OBJECTIVE: We evaluated the intracanal antibacterial potential of tetracycline or erythromycin mixed with calcium hydroxide (CH) against enterococci in vivo. STUDY DESIGN: Fifty-five teeth in which enterococci were present were dressed for 1 month with either tetracycline (28 teeth) or erythromycin (27 teeth) mixed with CH. RESULTS: The tetracycline mixture was effective against enterococci in 22 teeth (79%). In 7 teeth, other microorganisms were recovered, resulting in a total antimicrobial effect of 54%. The corresponding results for erythromycin were 96% and 56%. CONCLUSIONS: The antimicrobial treatment of CH in combination with either erythromycin or tetracycline had a significant effect on enterococci, but the overall antimicrobial effect was relatively weak. Erythromycin mixed with CH seems to be a valuable option in the battle against monoinfections of enterococci.
The purpose of this study was to evaluate the dentinal tubule penetration of root canal sealers after root canal dressing with calcium hydroxide (Ca(OH)2). Forty-two single-rooted teeth were instrumented to size 60. Six teeth served as the control group, and the remaining teeth were assigned to two groups. Root canals of the first group were filled with the Ca(OH)2 paste; the second group was filled with TempCanal, and all were incubated for 7 days. The samples were either irrigated with only NaOCl or with EDTA, followed by NaOCl to remove Ca(OH)2. All of the teeth were obturated with CRCS, AH26, and Ketac Endo by a lateral condensation technique. The specimens were then kept at the same conditions for another 7 days, and then all of the roots were prepared for scanning electron microscopic evaluation. Scanning electron microscopic examination revealed that Ca(OH)2 was not completely removed from the root canal surfaces, and root canal sealers did not penetrate into the dentinal tubules when only NaOCl was used. EDTA followed by NaOCl irrigation resulted in complete removal of Ca(OH)2 and root canal sealers penetrated into the dentinal tubules.
In the two case reports, pulpectomy is described as the treatment of choice for a necrotic pulp. A calcium hydroxide paste was used as root canal filling. Its simple application and subsequent good resorption during by the eruption of the permanent tooth strengthened that choice.
The objective of this study was to investigate the antimicrobial action of mineral trioxide aggregate (MTA), Portland cement, calcium hydroxide paste (CHP), Sealapex and Dycal. The chemical elements of MTA and two Portland cements were also analyzed. Four standard bacterial strains: Staphylococcus aureus (ATCC 6538), Enterococcus faecalis (ATCC 29212), Pseudomonas aeruginosa (ATCC 27853), Bacillus subtilis (ATCC 6633), one wild fungus, Candida albicans (ICB/USP-562), and one mixture of these were used. Thirty Petri plates with 20 ml of BHI agar were inoculated with 0.1 ml of the experimental suspensions. Three cavities, each one measuring 4 mm in depth and 4 mm in diameter, were made in each agar plate using a copper coil and then completely filled with the product to be tested. The plates were pre-incubated for 1 h at environmental temperature followed by incubation at 37 degrees C for 48 h. The diameters of the zones of microbial inhibition were then measured. Samples from diffusion and inhibition halos were extracted from each plate and immersed in 7 ml BHI broth and incubated at 37 degrees C for 48 h. Analyses of chemical elements present in MTA and in two samples of Portland cement were performed with a fluorescence spectrometer Rx. The results showed that the antimicrobial activity of CHP was superior to those of MTA, Portland cement, Sealapex and Dycal, for all microorganisms tested, presenting inhibition zones of 6-9.5 mm and diffusion zones of 10-18 mm. MTA, Portland cement, and Sealapex presented only diffusion zones and among these, Sealapex produced the largest zone. Dycal did not show inhibition or diffusion zones. Portland cements contain the same chemical elements as MTA except that MTA also contains bismuth.
In this in vitro study, we investigated the effects of the use of two different calcium hydroxide (Ca(OH)2) preparations as an intracanal dressing on the sealing ability of two different sealers were investigated. Eighty-eight freshly extracted, single-rooted maxillary anterior teeth were used. After the root canals were hand-instrumented, they were divided into six groups of 10 each. The root canals were dressed with Ca(OH)2 paste, either mixed with sterile water (in groups 1 and 2) or with glycerine (in groups 3 and 4). The dressed root canals were incubated in 100% humidity at 37 degrees C for 7 days. In groups 5 and 6, the root canals were not dressed. After the root canal dressings were removed by irrigation with 5.25% NaOCl and reaming with a K-type file, all canals of the experimental groups were obturated with sealer and gutta-percha using a cold lateral condensation technique. Calciobiotric Root Canal Sealer, (CRCS), (in groups 1, 3 and 5) and Diaket (in groups 2, 4 and 6) were used as sealers. All specimens were placed in India ink for 7 days, and the amount of apical leakage was scored. Eight further prepared specimens were dressed with Ca(OH)2 plus water or Ca(OH)2 plus glycerine and examined with scanning electron microscopy (SEM) following the removal of dressings. There was a statistical difference in the leakage patterns amongst the 6 experimental groups (P < 0.05). Specimens in group 2 exhibited less leakage than the other experimental groups, except group 4 (P < 0.05). There were no other significant interactions. SEM examination revealed that Ca(OH)2 crystals were present on the surface of smear layer in both groups where Ca(OH)2 paste had been placed, but they did not penetrate into the dentinal tubules.
Synthetic materials used in dentistry may trigger various inflammatory responses. In order to evaluate biocompatibility, standardized implants of Calcium Hydroxide (CH), Glass Ionomer Cement (GIC) and Light-activated Dental Adhesive (LDA) were surgically introduced into Wistar rats' back bone. Six (experimental) animal groups, five each, and two Sham (S) groups were studied after 15 and 30 days from surgery. In each animal, the density of mast cells and interstitial fibrosis volume was evaluated by quantitative light microscopy. In addition, the interaction between the disk material and its fibrous capsule was evaluated by scanning electron microscopy. The density of mast cells per area (N(A)[mast cells]) was lower in CH group than in LDA group. GIC group displayed N(A)[mast cells] results intermediate between CH and LDA groups (p<0.05). The smallest interstitial fibrosis volume density (Vv[f]) was observed in CH group, then in GIC group, while the greatest in LDA group. After 30 days, the fibrosis in LDA group was 30% higher than in CH group (p<0.05). In S group, discreet fibrosis restricted to surgical area was present, with few mast cells near the vessels. Significant interaction between fibrous capsule and the surrounding disk material was most evident in CH group. The implanted materials induced mast cell migration, distinct fibrosis development, suggesting that CH is the most biocompatible material among those tested.
AIM: To evaluate the capacity to remove a calcium hydroxide (Ca(OH)2) paste from the root canal and to evaluate the efficacy of Ca(OH)2 removal during passive ultrasonic irrigation using either sodium hypochlorite (NaOCl) or water as an irrigant. METHODOLOGY: Sixteen mandibular premolars were used. Each root was prepared to the apical foramen using GT instruments of size 30, 0.06 taper. Each root was split longitudinally. In one half of the root, a groove was cut in the canal wall 2-6 mm from the apex which was then filled with a Ca(OH)2 paste. Subsequently the roots were reassembled. In group 1 (n = 16), the teeth were ultrasonically irrigated using 50 mL 2.0% NaOCl as the irrigant. Group 2 (n = 16) was treated in the same manner as group 1, but using 50 mL water in place of the NaOCl. In group 3 (n = 16), the teeth were irrigated by syringe injection of 50 mL 2.0% NaOCl. The quantity of remaining Ca(OH)2 in the groove was scored and the data analysed with Kruskal-Wallis and Mann-Whitney tests. RESULTS: The difference in remaining Ca(OH)2 between all groups was statistically significant (P < 0.001). Group 1 had significantly lower scores than group 2 (P < 0.001) and group 3 (P = 0.002), but there was no significant difference between groups 2 and 3 (P = 0.765). CONCLUSIONS: Passive ultrasonic irrigation with 2% NaOCl was more effective in removing Ca(OH)2 paste from artificial root canal grooves than syringe delivery of 2% NaOCl or water as irrigant.
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