pH changes in root dentin after root canal dressing with gutta-percha points containing calcium hydroxide

A comparison of hydroxyl ion diffusion through root dentine from various calcium hydroxide preparations

Different calcium hydroxide [Ca(OH)2 ] formulations are available. The aim was to assess differences in hydroxyl ion release with different formulations. Sixty-six teeth were divided one control (n = 6) and four experimental (n = 15) groups: (i) Pulpdent Paste; (ii): DT Temporary Dressing; (iii): Ca(OH)2 powder/saline; (iv): Ca(OH)2 points; (v): no medicament. pH was measured in inner dentine and outer dentine cavities over 12 weeks. Inner dentine pH rose rapidly for all groups except the points and controls. Peak pH was reached by day 2 before dropping and stabilising (8.0-9.2). Outer dentine pH rose steadily until day 21 for aqueous solutions and then stabilised (8.0-8.5). The points had minimal pH increase for the entire period. There were no significant differences in hydroxyl ion release between the aqueous solutions. Type of paste base did not affect release and diffusion of hydroxyl ions which continued for 84 days.

An In-vitro Evaluation of the pH Change Through Root Dentin Using Different Calcium Hydroxide Preparations as an Intracanal Medicament

CONTEXT

The aim of the study was to evaluate the pH variation in the surrounding medium after the use of two different vehicles of Calcium hydroxide - Saline (aqueous), Propylene glycol (viscous) and Calcium hydroxide containing guttapercha points over a period of 7 days as an intracanal medicament.

MATERIALS AND METHODS

Sixty single rooted premolars were decoronated at the cementoenamel junction and cleaned and shaped uptil size 40 master apical file. External defects were made on the mesial surface in the coronal third of the roots and divided randomly into 4 groups. One control and three experimental. In the control - group I the root canals were left empty. In the experimental groups - group II was filled with Ca(OH)2 + saline, group III was filled with Ca(OH)2 + propylene glycol and group IV the root canals were filled with Calcium hydroxide points. The coronal accesses were sealed with 3mm of Cavit G and all the surfaces of the root except the defect were covered with 3 coats at Nail varnish. The samples were then placed in air tight vials containing 2ml of distilled water. The vials were kept in an incubator and the pH of the surrounding medium was measured using a digital pH meter after 1,3,5 and 7 days respectively.

RESULTS

A statistically significant difference (p<0.05) existed between the experimental groups over the observation period. At day 1, a high pH was recorded by the calcium hydroxide points and saline groups and a lower pH by the propylene group. At day's 3 and 5, the maximum pH was recorded by the propylene glycol group and minimum by the calcium hydroxide points and saline groups. At day 7, the pH of all the groups had dropped, with propylene glycol recording the maximum pH followed by saline and lastly calcium hydroxide points.

CONCLUSION

Within the limitations of this study, a viscous vehicle is better among other vehicles, calcium hydroxide paste of propylene glycol provided the highest 7 days release of hydroxyl ions.

Evaluation of calcium ion release and change in pH on combining calcium hydroxide with different vehicles

Introduction:

Intracanal medicaments have traditionally been used in endodontics to disinfect root canals between appointments. Calcium hydroxide is widely used as an intracanal medicament for disinfection and to promote periapical healing. It is stable for long periods, harmless to the body, and bactericidal in a limited area. The efficacy of calcium hydroxide as a disinfectant is dependent on the availability of the hydroxyl ions in the solution that depends on the vehicle in which the calcium hydroxide is carried. In general, three types of vehicles are used: Aqueous, viscous or oily. Some in vitro studies have shown that the type of vehicle has a direct relationship with the concentration and the velocity of ionic liberation as well as with the antibacterial action when the paste is carried into a contaminated area.

Aim of the Study:

To evaluate the calcium ion release and measure the change in pH of the environment that occurred when calcium hydroxide was combined with different vehicles (distilled water, propylene glycol, calcium hydroxide containing gutta-percha points and chitosan) over different time periods.

Materials and Methods:

Forty single rooted mandibular first premolar teeth were decoronated for this study. Working length was established and the root canals were enlarged and irrigation accomplished with 2 ml of NaOCl solution after every file. The teeth were then randomly divided into four groups. The canals were then packed with different preparations of calcium hydroxide using the following vehicles-distilled water, propylene glycol, gutta-percha points and chitosan. Calcium ion release in different groups was analyzed using an ultraviolet spectrophotometer at 220 nm. The change in pH of was determined using a pH meter. Results were statistically evaluated using one-way ANOVA test.

Result:

For calcium ion release, Group 2 showed cumulative drug release of 81.97% at the end of 15 days, whereas Group 1, 3 and 4 showed a release of 99.53, 17.98, 74.93% respectively with a significant difference among all groups. Group 1 reached the highest Ca²⁺ level (39.79%) at the end of 1 day but showed almost complete release of calcium hydroxide at the end of 15 days. Group 3 showed least calcium ion release (17.98%) at 15 days. Group 4 showed a sustained release of Ca⁺² ions from 74% at 15 days to 95% at the end of 30 days. After the 1^st h; Group 1 showed the highest pH level (11.8). However, pH reduced to 7.8 at the end of 30 days in this group. Group 2 showed the highest pH value (10.35), followed by Group 4 (10.32) after 30 days.

Conclusion:

Chitosan can be used as a promising vehicle for calcium hydroxide to maintain an alkaline pH and to allow sustained release of calcium ions in the root canal system.

Influence of calcium hydroxide points on the quality of intracanal dressing filling

Purpose

The aim of this study was to evaluate, in vitro, the quality of calcium hydroxide [Ca(OH)₂] paste filling (Ultracal, Ultradent) associated or not with Ca(OH)₂-containing gutta-percha points (Calcium Hydroxide Plus Points™, Roeko) in curved root canals.

Material and Methods

One hundred and twenty roots of extracted human teeth, randomly divided into three curvature ranges (mild - 0 to 14°; moderate - 15° to 29°; severe - >30°) were used. After chemomechanical preparation, the roots were assigned to 4 groups (n=30), according to the technique of intracanal dressing placement: group 1 - Ca(OH)₂ paste was applied with a lentulo spiral; group 2 - Ca(OH)₂ paste was applied with a lentulo spiral and a Ca(OH)₂ point was inserted into the canal; group 3 - Ca(OH)₂ paste was applied with a Navitip™ tip (supplied with Ultracal system); group 4 - Ca(OH)₂ paste was applied with a Navitip™ tip and a Ca(OH)₂ point was inserted into the canal. The roots were cleared and the quality of apical third filling was assessed by a calibrated experienced examiner. The specimens were examined under stereomicroscopy and scored 1 to 4 (i.e., from inadequate to complete root canal filling). The results were analyzed statistically by ANOVA and Duncan's post hoc test at 5% significance level.

Results

There were no statistically significant differences (p>0.05) among the curvature degrees in groups 1, 3 and 4. Severely curved roots in group 2 presented bordering significance (p=0.05). The groups that associated the use of Ca(OH)₂ paste and points (2 and 4) showed better apical filling than the other groups, but this difference was statistically significant (p<0.001) only for roots with severe curvature.

Conclusion

According to the results of this study, the curvature degree did not influence the quality of filling. The techniques that used Ca(OH)₂-containing gutta-percha points yielded better filling of the apical third in roots with severe curvature.

Growth at high pH increases Enterococcus faecalis adhesion to collagen

AIM

To evaluate the effect of growth at pH levels from 7.1 to 9.5 on the adherence of Enterococcus faecalis to bovine serum albumin (BSA) and collagen type I.

METHODOLOGY

Enterococcus faecalis strain A197A was grown in broth of adjusted pHs varying between 7.1 and 9.5. Aliquots of bacterial suspensions were added to wells coated either with BSA or with collagen type I. Bacteria adhering to the surfaces were stained with crystal violet. Spectrophotometric measurements of the dissolved stain were used to assess the number of bacteria adhering to the surfaces. The data obtained were analysed using the Kolmogorov-Smirnov test, Levene's test and Student's t-test, with alpha = 0.05 as the level for statistical significance.

RESULTS

The adhesion of E. faecalis to BSA-coated surfaces decreased inversely with alkalinity of the growth medium. The pH 7.1-grown bacteria bound to BSA significantly more than the other BSA groups. On the contrary, the adhesion to collagen type I-coated surfaces of bacteria grown at pH 8.0 and 8.5 was significantly greater than for those grown at pH 7.1.

CONCLUSIONS

A minor increase in pH up to 8.5, which may be a consequence of insufficient treatment with alkaline medicaments such as calcium hydroxide, increases the collagen-binding ability of E. faecalis, in vitro. This can be a critical mechanism by which E. faecalis predominates in persistent endodontic infections.

pH changes in root dentin after intracanal placement of improved calcium hydroxide containing gutta-percha points

The in vitro pH changes in root dentin over a period of 2 weeks was investigated in 48 extracted bicuspids after intracanal placement of either Roeko Calcium Hydroxide Plus Points, aqueous calcium hydroxide paste, or gutta-percha points (control group) after root canal preparation. Microelectrodes were placed in outer and inner root dentin at cervical, middle, and apical thirds of the root to measure the pH at 1 h, 2 h, 3 h, 1 day, 3 days, 7 days, and 14 days. Roeko Calcium Hydroxide Plus Points reached a peak inner dentine pH of 11.67 and a peak outer dentine pH of 10.82 at 3 h. In addition, Roeko Calcium Hydroxide Plus Points maintained an outer dentine pH above 9.5 for approximately 2 days, whereas the aqueous calcium hydroxide paste did not reach this pH. However, the alkalinity in dentin with Roeko Calcium Hydroxide Plus Points was maintained for 7 days only, whereas aqueous calcium hydroxide paste maintained an alkaline environment throughout the 2-week period.