Influence of different vehicles on the pH of calcium hydroxide pastes

Biomimetic Tissue Engineering Strategies for Craniofacial Applications

Biomimetics is the science of imitating nature's designs and processes to create innovative solutions for various fields, including dentistry and craniofacial reconstruction. In these areas, biomimetics involves drawing inspiration from living organisms/systems to develop new materials, techniques, and devices that closely resemble natural tissue structures and enhance functionality. This field has successfully demonstrated its potential to revolutionize craniofacial procedures, significantly improving patient outcomes. In dentistry, biomimetics offers exciting possibilities for the advancement of new dental materials, restorative techniques, and regenerative potential. By analyzing the structure/composition of natural teeth and the surrounding tissues, researchers have developed restorative materials that mimic the properties of teeth, as well as regenerative techniques that might assist in repairing enamel, dentin, pulp, cementum, periodontal ligament, and bone. In craniofacial reconstruction, biomimetics plays a vital role in developing innovative solutions for facial trauma, congenital defects, and various conditions affecting the maxillofacial region. By studying the intricate composition and mechanical properties of the skull and facial bones, clinicians and engineers have been able to replicate natural structures leveraging computer-aided design and manufacturing (CAD/CAM) and 3D printing. This has allowed for the creation of patient-specific scaffolds, implants, and prostheses that accurately fit a patient's anatomy. This review highlights the current evidence on the application of biomimetics in the fields of dentistry and craniofacial reconstruction.

An in vitro comparison of calcium ions release and diffusion ability of calcium hydroxide-based intracanal medicament in combination with three different vehicles like propolis, chitosan, and propylene glycol

Context

Calcium hydroxide, which is an intracanal medicament, is widely used in endodontics. Improvements can be made to its effectiveness, as calcium hydroxide is dependent on the vehicle.

Aim

The study aims to compare and evaluate the release and diffusion ability of calcium hydroxide when mixed with - propolis, chitosan, and propylene glycol.

Methods

For this study, 33 single-rooted extracted premolar teeth have been decoronated. After the working length and enlargement of the canals had been established, different preparations of calcium hydroxide with vehicles such as propolis, chitosan, and propylene glycol were loaded into the canals. Atomic absorption spectrophotometry was used to analyze the release of calcium ions in three groups, while a digital pH meter was used to determine an acid change.

Results

Atomic absorption spectrophotometry showed sustained releases of calcium ions and the digital pH meter showed increased diffusion capacity in the propylene glycol paste group in comparison to the other two groups.

Conclusion

Propylene glycol vehicle made it easier to enter calcium hydroxide into the dentinal tubules.

Novel strategies enhancing endodontic disinfection: Antibacterial biodegradable calcium hydroxide nanoparticles in an ex vivo model

Due to the high failure rates associated to endodontic disinfection, this study aimed to investigate the antibacterial properties of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) loaded with Ca(OH)2 for endodontic disinfection procedures. Ca(OH)2 NPs production and physicochemical characterization were carried out as well as multiple antibacterial tests using three bacterial strains and an ex vivo model of endodontic infection with extracted human teeth. Agar diffusion test and broth dilution determined the inhibition growth zones (n = 5) and the minimal inhibitory concentration (MIC, n = 5), respectively. Cell viability was assessed using Live/Dead staining with confocal microscopy (n = 5). Data was analysed using ANOVA followed by post-hoc analysis. After 24 h of incubation, Ca(OH)₂ NPs demonstrated a MIC of 10 µg/mL for Porphyromonas gingivalis (p < 0.001) and Enterococcus faecalis and 5 µg/mL for Fusobacterium nucleatum (p < 0.001). Although the agar diffusion test did not exhibit any inhibition area for Ca(OH)2 nor for Ca(OH)₂ NPs, this was probably due to the buffering effect of the agar medium. However, the antibacterial capacity was confirmed in an ex vivo model, where instrumentalized teeth were infected with Enterococcus Faecalis and treated after 28 days of culture. A significant reduction in bacterial metabolic activity was confirmed for Ca(OH)2 NPs (40 % reduction with a single dose) and confirmed by Live/Dead staining. In conclusion, Ca(OH)₂-loaded PLGA NPs present promising antibacterial efficacy for endodontic disinfection procedures.

Therapeutic Potential of Chlorhexidine-Loaded Calcium Hydroxide-Based Intracanal Medications in Endo-Periodontal Lesions: An Ex Vivo and In Vitro Study

Endo-periodontal lesions are challenging clinical situations where both the supporting tissues and the root canal of the same tooth are infected. In the present study, chlorhexidine (CHX)-loaded calcium hydroxide (CH) pastes were used as intracanal medications (ICMs). They were prepared and tested on pathogens found in both the root canal and the periodontal pocket. Exposure to 0.5% and 1% CHX-loaded ICMs decreased the growth of Porphyromonas gingivalis and was effective in eradicating or inhibiting an Enterococcus faecalis biofilm. CH was injected into the root canal of extracted human teeth immersed in deionized water. CHX-loaded ICMs resulted in the transradicular diffusion of active components outside the tooth through the apex and the lateral dentinal tubules, as shown by the release of CHX (from 3.99 µg/mL to 51.28 µg/mL) and changes in pH (from 6.63 to 8.18) and calcium concentrations (from 2.42 ppm to 14.67 ppm) after 7 days. The 0.5% CHX-loaded ICM was non-toxic and reduced the release of IL-6 by periodontal cells stimulated by P. gingivalis lipopolysaccharides. Results indicate that the root canal may serve as a reservoir for periodontal drug delivery and that CHX-based ICMs can be an adjuvant for the control of infections and inflammation in endo-periodontal lesions.

The Vehicles of Calcium Hydroxide Pastes Interfere with Antimicrobial Effect, Biofilm Polysaccharidic Matrix, and Pastes' Physicochemical Properties

The objective of the present study was to investigate the pH, volumetric alteration, antimicrobial action, and effect on biofilm matrix polysaccharides of calcium hydroxide (CH) pastes with different vehicles available in endodontics: CH + propylene glycol (CHP), UltraCal XS^®, Metapaste^®, and Metapex^®. The pH was analyzed at different time intervals using a pH meter. For volumetric alteration, a microtomographic assay was performed before and after immersion in water. Enterococcus faecalis was chosen for microbiological tests. The bacterial viability and extracellular matrix were quantified with direct contact evaluation (dentin blocks) and at the intratubular level (dentin cylinders) using LIVE/DEAD BacLight and Calcofluor White dyes via confocal laser scanning microscopy (CLSM). Kruskal-Wallis and Dunn's tests were used to analyze pH and direct contact assays, while one-way ANOVA and Tukey tests were used to analyze volumetric alteration and intratubular decontamination (α = 0.05). Higher pH values were obtained during the initial days. Volumetric alterations were similar in all groups. Lower bacterial viability was obtained for dentin blocks and cylinders when CH pastes were used. UltraCal XS and Metapex had lower values for the extracellular matrix. The pH of all CH pastes decreased with time and did not promote medium alkalization for up to 30 days. CH paste can reduce bacterial viability through direct contact and at an intratubular level; however, UltraCal XS and Metapex are involved with lower volumes of extracellular matrices.

Calcium hydroxide-loaded PLGA biodegradable nanoparticles as an intracanal medicament

AIM

To develop a formulation in which calcium hydroxide (Ca(OH)₂) was successfully loaded into poly(lactic-co-glycolic acid) (PLGA) biodegradable nanoparticles (NPs) to be used in the field of endodontics as an intracanal medicament, including NP optimization and characterization, plus drug release profile of the NPs compared with free Ca(OH)₂. Additionally, the depth and area of penetration of the NPs inside the dentinal tubules of extracted teeth were compared with those of the free Ca(OH)₂.

METHODOLOGY

Ca(OH)₂ NPs were prepared using the solvent displacement method. NPs was optimized with a central composite design to obtain a final optimized formulation. The morphology of the NPs was examined under transmission electron microscopy (TEM), and characterization was carried out using X-ray diffraction (XRD), Fourier transform infrared (FTIR) and differential scanning calorimetry (DSC). The drug release profile of the Ca(OH)₂ NPs and free Ca(OH)₂ was evaluated up to 48 h. Finally, the depth and area of penetration inside the dentinal tubules of extracted teeth were examined for both the Ca(OH)₂ NPs and free Ca(OH)₂ using the Mann-Whitney U test to determine any significant differences.

RESULTS

Utilizing the optimized formulation, the Ca(OH)₂ NPs had an average size below 200 nm and polydispersity index lower than 0.2, along with a highly negative zeta potential and suitable entrapment efficiency percentage. The spherical morphology of the Ca(OH)₂ NPs was confirmed using TEM. The results of the XRD, FTIR and DSC revealed no interactions and confirmed that the drug was encapsulated inside the NPs. The drug release profile of the Ca(OH)₂ NPs exhibited a prolonged steady release that remained stable up to 48 h with higher concentrations than the free Ca(OH)₂. After examination by confocal laser scanning microscopy, Ca(OH)₂ NPs had a significantly greater depth and area of penetration inside dentinal tubules compared with the free drug.

CONCLUSIONS

Ca(OH)₂-loaded PLGA NPs were successfully optimized and characterized. The NPs exhibited a prolonged drug release profile and superior penetration inside dentinal tubules of extracted teeth when compared to Ca(OH)₂ .

To evaluate and compare the compressive strength of root dentin exposed to calcium hydroxide, mixed with various vehicles for a period of 30 days – An in vitro study

Background:

Long-term use of intracanal medicaments such as calcium hydroxide (CH) reduces the fracture resistance of dentin.

Aim:

This study aimed to evaluate and compare the compressive strength of root dentin exposed to CH, mixed with various vehicles after 30 days of placement.

Settings and Design:

Sixty single-rooted extracted human permanent premolars were collected, and complete instrumentation was done. Samples were divided into six groups.

Materials and Methods:

In Group I, no medicament was placed. In Group II, Group III, and Group IV, the root canals were filled with CH powder mixed with normal saline, distilled water, and local anesthetic solution. In Group V and Group VI, the root canals were filled with Metapaste and RC-Cal. Access cavities were sealed using IRM and were stored for 30 days. Teeth sectioned to obtain a 5 mm thick dentin cylinder subjected to compressive loading to evaluate the fracture resistance using a universal testing machine.

Statistical Analysis:

Results were analyzed using one-way ANOVA and multiple comparisons using Bonferroni test.

Results:

Highest mean compressive strength was recorded in Group I followed by Group II, Group IV, Group VI, Group III, and Group V.

Conclusions:

CH when used as a root canal dressing material will reduce the compressive strength of the teeth irrespective of the form of CH and vehicle.

Hydrophilic Natural Polymers for Sustained-controlled Release of Calcium Hydroxide

Calcium Hydroxide (CH) is commonly employed as intracanal medicament in endodontics. In order to maximize its therapeutic effects, it is essential to develop new approaches for preparing the controlled drug release systems which, in turn, facilities the dissociation of CH into calcium and hydroxyl ions. This work studies the sustained-controlled release of calcium ions and the effect of pH changes on the different formulation of CH with hydrophilic natural polymers over a period of 30 days. Various formulations were prepared by combining CH with gelatin, aloe vera and gum tragacanth. Root canals of 60 human teeth were instrumented and filled with a different formulation of CH and suspended in plastic tubes containing distilled water. Three formulas of polymer/CH were evaluated, and pure CH powder was used as a control. At specific time intervals, the calcium ions release and the pH changes of the medium in different formulations were analyzed. The main interactions between the studied polymers and CH were investigated using FTIR spectra. The antibacterial activity of formulations against Enterococcus faecalis was also studied. Faster release of CH was observed for aloe vera/CH. Gum tragacanth/CH showed a slow-release during the first 15 days. In contrast, only Gelatin/CH formulation showed a prolonged release with statistically significant differences (P < 0.05). The pure CH showed significantly higher pH values than the other formulations. The Gelatin/CH formulation was a better sustained-release system than the pure CH, and it can be used as a promising vehicle for CH in the root canal treatment.

Biomimetic Aspects of Restorative Dentistry Biomaterials

Biomimetic has emerged as a multi-disciplinary science in several biomedical subjects in recent decades, including biomaterials and dentistry. In restorative dentistry, biomimetic approaches have been applied for a range of applications, such as restoring tooth defects using bioinspired peptides to achieve remineralization, bioactive and biomimetic biomaterials, and tissue engineering for regeneration. Advancements in the modern adhesive restorative materials, understanding of biomaterial-tissue interaction at the nano and microscale further enhanced the restorative materials' properties (such as color, morphology, and strength) to mimic natural teeth. In addition, the tissue-engineering approaches resulted in regeneration of lost or damaged dental tissues mimicking their natural counterpart. The aim of the present article is to review various biomimetic approaches used to replace lost or damaged dental tissues using restorative biomaterials and tissue-engineering techniques. In addition, tooth structure, and various biomimetic properties of dental restorative materials and tissue-engineering scaffold materials, are discussed.

Chitosan/gelatin as a new nano-carrier system for calcium hydroxide delivery in endodontic applications: Development, characterization and process optimization

The main aim of this study is preparation, optimization and in vitro characterization of Chitosan/Gelatin nano-carriers (NCs) for calcium hydroxide (CH) to improve its therapeutic potential. The designed system can be used in the endodontic applications demanding a sustained release of calcium and hydroxyl ions. Modeling and optimization of CH loaded polymeric NCs were performed using response surface methodology (RSM) based on central composite surface statistical design. The effect of Chitosan concentration (0.1-1% w/v), Gelatin concentration (0.1-1% w/v) and CH concentration (0.05-0.4% w/v) on the particle size, polydispersity index (PDI), drug loading (DL) and encapsulation efficiency (EE) of CH loaded polymeric NCs were investigated. Optimized CH loaded polymeric NCs formulation which obtained using RSM showed spherical and smooth surface with a particle size of 292 nm, PDI of 0.32, DL of 88.8% and EE of 99%. Optimized formulation was evaluated for in vitro calcium ion release in phosphate buffer solution (PBS) at pH 7.4 for 14 days. The presence of hydrogen bonding and some intermolecular interactions between Chitosan/Gelatin polymeric materials were confirmed using Fourier transform infrared (FTIR) analysis. These interactions enable Chitosan/Gelatin NCs to load CH and maintain sustained release of Calcium ions from CH during experimental period.

A Comparative Study of Ion Diffusion from Calcium Hydroxide with Various Herbal Pastes through Dentin

AIM

The aim of this study was to evaluate the diffusion ability of ions through dentinal tubules of different nonalcoholic calcium hydroxide-containing herbal pastes and compare it with the calcium hydroxide paste prepared with saline.

MATERIALS AND METHODS

A total of 36 single-rooted premolar teeth were used in this study. The tooth crowns were removed and the root canals were prepared. Depending on the vehicle to be used for preparing calcium hydroxide pastes, six groups were made: Group I: Ca(OH)₂ saline paste (control group), group II: Ca(OH)₂ papaya latex paste, group III: Ca(OH)₂ coconut water paste, group IV: Ca(OH)₂ Ashwagandha (Withania somnifera) paste, group V: Ca(OH)₂ Tulsi (Ocimum tenuiflorum) paste, and group VI: Ca(OH)₂ garlic (Allium sativum) paste. After biomechanical preparation, calcium hydroxide herbal paste dressings were applied and sealed with resin-based cement. The teeth were placed in containers with deionized water, and the pH of the water was measured at regular intervals over 3, 24, 72, and 168 hours.

RESULTS

We observed that all herbal pastes allowed the diffusion of ions, but pastes prepared with Ashwagandha and papaya latex showed more ion diffusion after 168 hours and marked increase in pH, depicting better support for calcium hydroxide action.

CONCLUSION

We conclude that Ashwagandha and papaya latex allow better diffusion of calcium hydroxide through den-tinal tubules, thus enhancing its action, and advise its use as a vehicle for placing intracanal medicament.

HOW TO CITE THIS ARTICLE

Dausage P, Dhirawani RB, Marya J, Dhirawani V, Kumar V. A Comparative Study of Ion Diffusion from Calcium Hydroxide with Various Herbal Pastes through Dentin. Int J Clin Pediatr Dent 2017;10(1):41-44.

Antimicrobial Activity and Physicochemical Properties of Calcium Hydroxide Pastes Used as Intracanal Medication

INTRODUCTION

The aim of the present study was to evaluate the pH, calcium release, solubility, and antimicrobial action against biofilms of calcium hydroxide + saline solution, Calen (SS White Artigos Dentários Ltd, Rio de Janeiro, Brazil) (CH/P), Calen camphorated paramonochlorophenol (CMCP) (CH/CMPC), and calcium hydroxide + chlorhexidine (CH/CHX) pastes.

METHODS

The pH of the pastes was determined with a calibrated pH meter placed in direct contact with each paste. The root canals of acrylic teeth (N = 10) were filled with the previously mentioned intracanal dressings and immersed in ultrapure water to measure hydroxyl (pH meter) and calcium ion release (atomic absorption spectrophotometer) at time intervals of 3, 7, 15, and 30 days. To assess solubility, the root canals of acrylic teeth (N = 10) were filled with the previously mentioned pastes and scanned by micro-computed tomographic imaging before (initial) and after 7, 15, and 30 days of immersion in ultrapure water. The solubility of each specimen was the difference between the initial and final volume scanning. For antimicrobial analysis, monospecies and dual-species biofilms were in vitro induced on dentin blocks (N = 20). Afterward, they were treated with the pastes for 7 days. Live/dead dye and a confocal microscope were used to measure the percentage of living cells. Data were statistically compared (P < .05).

RESULTS

The highest OH^- ion release values were found in 3 and 30 days. Ca²⁺ releases were greater in CH/CMCP. CH/P and CH/CMCP showed a higher percentage of volume loss values. CH/CHX presented the greatest antimicrobial action.

CONCLUSIONS

CH/P and CH/CMPC showed higher solubility values in the period analyzed. Seven days of contact may be insufficient for calcium hydroxide + saline solution, CH/P, and CH/CMCP pastes to kill bacterial cells in the biofilms studied. Chlorhexidine added to CH favored greater effectiveness against the previously mentioned bacterial biofilms.

Ions Release and pH of Calcium Hydroxide-, Chlorhexidine- and Bioactive Glass-Based Endodontic Medicaments

Abstract This study evaluated pH and release of calcium, sodium and phosphate ions from different medications in human dentin. Fifty premolars were prepared and randomly divided into groups: (CHX) - 2% chlorhexidine gel; (CHX + CH) - CHX + calcium hydroxide PA; (CH) - CH + propylene glycol 600; (NPBG) - experimental niobium phosphate bioactive glass + distilled water; (BG) - bioactive glass (Bio-Gran) + distilled water. The specimens were immersed in deionized water and the pH variations were measured. The quantification of ions in the solutions was made by inductively coupled plasma - atomic emission spectroscopy (ICP/AES) at 10 min, 24 h, 7, 14, 21 and 30 days. The results were analyzed by ANOVA and Tukey`s test, with a significance level of 5%. CH had the highest level of calcium ions release at 30 days, while CHX and BG released more sodium ions. BG, NPBG and CHX released a higher amount of phosphate ions. The pH of CH was significantly higher compared with the other groups. CH favored the greatest increase of pH and calcium ions release. The bioactive glasses released more sodium and phosphate ions and presented an alkaline pH immediately and after 30 days.

Measurement of pH and calcium ions release from different calcium hydroxide pastes at different intervals of time: Atomic spectrophotometric analysis

AIM

To evaluate the effect of different vehicles on pH and release of calcium ions from calcium hydroxide (CH) paste from apical third of root canals.

METHODS

40 single rooted extracted human mandibular premolars were instrumented with RevoS files (MicroMega) up to ISO size 40. The teeth were divided into 4 groups on the basis of vehicle as follows: Group I - calcium hydroxide mixed with 2% chlorhexidine; Group II - calcium hydroxide mixed with propylene glycol; Group III - calcium hydroxide mixed with glycerine; and Control - calcium hydroxide mixed with double distilled water. Each group had two subgroups (n = 5) on the basis of the calcium hydroxide delivery. Subgroup A - calcium hydroxide paste placed with spiral filler (Lentulospiral) subgroup B - calcium hydroxide paste placed with flat wire filler (Paste Inject). pH and calcium ion release was evaluated at 24 h, 48 h, 7th day, 15th day and 30th day using a pH meter and atomic absorption spectrophotometer respectively.

RESULTS

The calcium release from various groups was highest for CH+glycerine (Group III) followed by CH+chlorhexidine (Group I), CH+propylene glycol (Group II) and CH+double distilled water (control). At all the intervals the differences in calcium ion release among the groups were statistically significant (p < 0.05), except on day 7. Delivery technique did not have a significant effect on calcium ion release. Highest pH values were recorded from CH+glycerine group at day 30 for both the delivery systems, however rise in pH from day 1 to day 30 were non-significant in all groups with both delivery systems.

CONCLUSION

Demonstrable changes in calcium ion release occurred from the calcium hydroxide mixed with various vehicles and CH+glycerine group showed the maximum calcium ion release at all intervals and highest pH day 30.

Calcium Hydroxide Dressing Influences the Obturation of Simulated Lateral Canals

AIM

The aim of this study was to investigate the influence of calcium hydroxide dressing on the filling of simulated lateral canals by different obturation techniques.

MATERIALS AND METHODS

Sixty single-root-premolars were instrumented. Simulated lateral canals were drilled on each third of the roots. The teeth were divided into four groups: no dressing and obturation by lateral condensation technique (G1), dressing with calcium hydroxide and obturation by lateral condensation technique (G2), no dressing and obturation by hybrid technique (G3) and, dressing with calcium hydroxide and obturation by hybrid technique (G4). The teeth were maintained at 37°C in 100% humidity for 7 days, and obturation techniques were performed. Radiographs were taken and filled or unfilled lateral canals were counted. Data were analyzed using analysis of variance (ANOVA) followed by Tukey's test (a = 5%).

RESULTS

The hybrid technique filled large number of lateral canals as compared to lateral condensation technique, regardless the use of intracanal medication (p < 0.05). Calcium hydroxide decreased the number of lateral canals filled for both lateral and hybrid techniques (p < 0.05). Significant differences were observed when comparing the number of filled and unfilled lateral canals in the same root third of each group (p < 0.05).

CONCLUSION

Regardless the obturation technique, calcium hydroxide dressing reduced the penetration of filling material in simulated lateral canals.

CLINICAL SIGNIFICANCE

The persistence of calcium hydroxide residues reduces the penetration of filling material in simulated lateral canals, possibly representing a potential cause of failure in the future.

Evaluation of hydroxyl ion diffusion in dentin and injectable forms and a simple powder-water calcium hydroxide paste: an in vitro study

Background:

Intra canal medicaments are used to reduce the number of bacteria and reinfection in endodontic procedures. Calcium Hydroxide was introduced to endodontics by Herman as an intracanal antimicrobial agent.

Objectives:

The aim of this study was to present an injectable formulation of calcium hydroxide then compare the final pH of this new formulation with Metapaste and evaluate the effect of a mixture of Calcium Hydroxide powder with water on human extracted teeth.

Patients and Methods:

A total of 49 extracted human single-canal roots without caries and visible microcracks were included in this study. The teeth were decoronated and length of teeth was measured 1 mm anatomic apex. The canals were prepared using step-back technique. A cavity was created in the middle third of the buccal surface of all roots. The teeth were randomly divided into five groups: Group A (n = 15): In this group the root canals were filled with a mixture of calcium hydroxide powder and distilled water. Group B (n = 15): Included roots that were filled with Metapaste. Group C (n = 15): Root canals of this group were filled with new formulation of calcium hydroxide paste. Group D (negative control, n = 2): Included roots that were filled with a mixture of calcium hydroxide powder and distilled water. Group E (positive control, n = 2): Root canals of this group were filled with a mixture of calcium hydroxide powder and distilled water. Each tooth was immersed in a separate closed container with 4 mL saline for 2 weeks, pH of liquids were measured with an electrical pH meter after 7 and 14 days. The SPSS software (version 13) was used for data analysis. Analysis of variance (ANOVA) and Tukey tests were used for the statistical evaluation of results.

Results:

There was no significant difference at 7th day between the groups (P = 0.17) but at 14th day, a significant difference was observed between the groups (P = 0.04).

Conclusions:

The new formulation of calcium hydroxide with methylcellulose base has slower ionic dissolution, more durability and longevity of alkaline properties in comparison to combination of powder with distilled water and is comparable with other commercial products.

Nonsurgical treatment of two periapical lesions with calcium hydroxide using two different vehicles

Calcium hydroxide is used extensively as an intracanal medicament in endodontics for many years. It is used in various clinical situations such as to promote apexification, to repair perforation, to enhance healing of periapical lesions, to control root resorption, and to control exudation in teeth with persistent periapical inflammation. This paper presents a case report in which Ca(OH)2 was used as an intracanal medicament for treatment of periradicular lesions using two different vehicles in two different teeth of same patient.

Effect of indomethacin on surface treatment and intracanal dressing of replanted teeth in dogs

PURPOSE

This study evaluated the healing process of teeth replanted after root treatment and intracanal dressing with indomethacin alone or indomethacin with calcium hydroxide (Ca[OH]2).

MATERIALS AND METHODS

Through a case-control study, 24 teeth of 6 adult dogs were extracted, dried, and divided into 4 groups according to the root surface treatment protocols performed before replantation and the intracanal medication used after replantation. In group 1 (negative control), root surfaces were treated by immersion in a 0.9% saline solution and then replanted. In the other groups, the roots were immersed for 10 minutes in Ca(OH)2 (group 2), indomethacin (group 3), or a solution of indomethacin and Ca(OH)2 (group 4). After 2 weeks, group 1 teeth were subjected to single-visit root canal treatment and obturation with gutta-percha and sealer consisting of zinc oxide and eugenol. The teeth in the other groups were subjected to intracanal dressing with the same material used for immersion. After an additional period of 28 weeks, the animals were euthanized and the jaws containing the replanted teeth were processed for histologic analysis. Histometric values were statistically analyzed, with significance set at a P value less than or equal to .05.

RESULTS

Group 1 exhibited significantly more normal periodontium than group 4 (P = .02). Total resorption was greater in group 4 than in group 1 (P = .02). No statistically significant difference in the percentage of surface resorption or in total inactive resorption was observed between the groups.

CONCLUSIONS

The findings of this study suggest that intracanal dressing and topical root treatment with Ca(OH)2 with or without indomethacin is not recommended for teeth dried for 50 minutes, but the use of indomethacin alone as root surface treatment for delayed tooth replantation deserves further study using longer drying periods. In addition, the present results suggest that a single-visit root canal, performed up to 2 weeks after replantation, might be indicated for teeth dried for up to 50 minutes.

Comparative evaluation of pH and antibacterial effect of various calcium hydroxide combinations on E. faecalis and its effect on root strength: An in vitro study

AIM

To evaluate and compare the pH and antibacterial property of Ca(OH)(2) combined with iodine potassium iodide (IKI) or chlorhexidine (CHX) on E. faecalis and to assess and compare their effect on fracture resistance of root dentin.

MATERIALS AND METHODS

CHX (0.5%) The following test materials were used: Group I Calcium hydroxide + saline, Group II Calcium hydroxide + CHX (0.5%) and Group III Calcium hydroxide + IKI (2%). For antibacterial activity, 60 root dentin blocks (20 in each group) were infected by E. faecalis followed by placement of medicaments. At the end of 24 h and 7 days, 10 samples from each group were randomly chosen and assessed for antibacterial activity. For evaluation of root strength, 30 teeth were used and stored in sterile saline after placement of medicament. At the end of 30 days, samples were subjected to fracture resistance testing on the Universal Strength Testing Machine. Hounsfield strength testing machine, UK pH of the various calcium hydroxide combinations was determined with a digital pH meter.

STATISTICAL ANALYSIS

Kruskal Wallis test, Mann Whitney U test, and one-way ANOVA test for intergroup comparison and Wilcoxon's signed rank test and student's paired t test for intragroup comparison.

RESULTS

Group III showed significantly greater antibacterial activity against E. faecalis, followed by group II and control group. There was no statistically significant change in the pH and root strength values among all the groups.

CONCLUSION

The present study revealed that IKI or CHX in combination with Ca(OH)2 is an effective medicament against E. faecalis.

The pH changes of calcium hydroxide mixed with six different vehicles

OBJECTIVE

The aim of this study was to determine the pH values of calcium hydroxide mixed with sterile saline, glycerin, Xylocaine pump spray, Citanest Octapressin, 0.2% chlorhexidine solution, and Ultracaine DS.

STUDY DESIGN

pH values of all vehicles were measured by a pH microelectrode before calcium hydroxide powder was added to 2 mL of the vehicle until the solutions were saturated (n = 10). After all the saturated samples were prepared, pH was remeasured at 0, 10, 20, 30, and 45 minutes; 1, 24, and 48 hours; and 7 days.

RESULTS

When pH changes over the time course were compared, there were no statistically significant differences among mean pH values of 0, 10, 20, 30, 45 minutes, 1 hour, and 24 hours (P = .754) and mean pH values of these groups were significantly lower than the mean pH value of 48 hours and 7 days (P < .05). The highest mean pH value was observed at day 7. When different vehicles were compared, the lowest mean pH value was observed in sterile saline. The mean pH value of Xylocaine was the highest (P < .05).

CONCLUSION

The result of this study indicated that when calcium hydroxide powder was mixed with glycerin, Xylocaine pump spray, Citanest Octapressin, 0.2% chlorhexidine solution, Ultracaine DS, and sterile saline solution, the mixtures became very highly alkaline. However, the pH values of the mixtures increased significantly after 24 hours. When one of these vehicles is used for root canal medication, a calcium hydroxide mixture might be left in place at least 7 days.