Calcium hydroxide: root resorption and perio-endo lesions

Synthesis and characterization of experimental endodontic sealers containing bioactive glasses particles of NbG or 45S5

OBJECTIVE

This study evaluated the influence of adding bioactive glasses particles [Niobophosphate (NbG) or bioglass (45S5)] into endodontic cements in relation to physical, chemical and biological properties.

METHODS

The following commercial cements were used as comparison: AH Plus (Dentsply), Endofill (Dentsply), MTA Fillapex (Angelus) and EndoSequence (BC Sealer, Brasseler). Setting time, radiopacity, flow rate, weight loss/variation, alkaline capacity (pH) at different time-intervals (24h/48h/7d/14d/28d), bioactivity (assessed under SEM/EDS, FTIR/ATR and XDR) and cell viability were measured. Data were analyzed by One-way ANOVA/Holm-Sidak post-test (α = 5%) (normal distribution) and Kruskal-Wallis/Students-Newman-Keuls post-test (α = 5%) (non-normal distribution).

RESULTS

Bioactive endodontic experimental cements (containing NbG or 45S5) had high alkalinization capacity. The experimental cements presented high weight loss/variation (p < 0.001). 45S5 experimental cement did not present radiopacity (p < 0.001). AH Plus had the lowest cell cytotoxicity when compared to the other tested cements (p < 0.001). Regarding bioactivity, SEM/EDS analyses showed precipitates with high concentrations of Ca/P for 45S5 and NbG, as well as for MTA Fillapex and BC Sealer. AH plus and Endofill did not present bioactive precipitates. FTIR/ATR and XDR analyses found hydroxyapatite precursors for NbG, 45S5, MTA Fillapex and BC Sealer.

SIGNIFICANCE

The incorporation of bioactive particles (NbG or 45S5) into endodontic cements had potential to neutralize acidic environments and induced formation of hydroxyapatite precursors. Clinically, these would produce a cement that is bactericidal and have the potential to improve tissue healing. The improved radiopacity and flowability would facilitate the visualization of the material in the radiograph and the filling of anatomical complexities during root canal obturation. As drawbacks, the excessive weight loss and post-setting cytotoxicity could result in clinical degradation of the cement and adjacent tissue irritation for the patient.

Comparative study of pulpal responses to ProRoot MTA, Vitapex, and Metapex in canine teeth

Background/purpose

ProRoot MTA, Vitapex, and Metapex are widely used for pulp treatment of primary tooth. The aim of this study was to compare the pulpal responses to ProRoot MTA, Vitapex, and Metapex in a canine model of pulpotomy.

Materials and methods

Pulpotomy procedure was performed to 34 teeth (21 incisors and 13 premolars) and ProRoot MTA, Vitapex or Metapex was applicated to artificially exposed pulp tissues. After 13 weeks, the teeth were extracted and processed with hematoxylin-eosin staining for histologic evaluation. All specimens were evaluated in several categorys related to calcific barrier, inflammatory responses and the area of calcific barrier formation was measured.

Results

Most of the specimens in the ProRoot MTA group developed a calcific barrier at the pulp amputation site and showed a low level of inflammatory response. However, in comparison to ProRoot MTA group, a small amount of calcific barrier formed in Vitapex and Metapex groups.

Conclusion

This in vivo study found that Vitapex and Metapex induced similar pulpal responses but showed poor outcomes compared with using ProRoot MTA. Vitapex and Metapex are therefore not good substitutes for ProRoot MTA in direct pulp capping and pulpotomy.

Flow characteristics and alkalinity of novel bioceramic root canal sealers

Objective

This study aimed to examine the physical properties (pH and flow) of 2 novel bioceramic sealers.

Materials and Methods

The tested sealers were a calcium hydroxide sealer (Sealapex) and 2 bioceramic sealers (BioRoot RCS and TotalFill BC Sealer). Flow measurements were conducted according to ISO 6876/2012, with a press method of 0.05 mL of sealer. The pH of fresh samples was tested immediately after manipulation, while set samples were stored for 3 times the recommended setting time. The predetermined time intervals ranged from 3 minutes to 24 hours for fresh samples and from 10 minutes to 7 days and 4 weeks for the set samples. Analysis of variance was performed, with p = 0.05 considered indicating significance.

Results

The mean flow values were 26.99 mm for BioRoot, 28.19 for Sealapex, and 30.8 mm for TotalFill BC Sealer, satisfying the ISO standard. In the set samples, BioRoot RCS had higher pH values at 24 hours to 1 week after immersion in distilled water. At 2 weeks, both bioceramic sealers had similar pH values, greater than that of Sealapex. In the fresh samples, the bioceramic sealers had significantly higher initial pH values than Sealapex (p < 0.05). At 24 hours post-immersion, all sealers showed an alkaline pH, with the highest pH observed for TotalFill.

Conclusions

The TotalFill BC Sealer demonstrated the highest flow. The bioceramic sealers initially presented higher alkaline activity than the polymeric calcium hydroxide sealer. However, at 3 and 4 weeks post-immersion, all sealers had similar pH values.

Clinical Evaluation of Ozone on Dentinal Lesions in Young Permanent Molars using the Stepwise Excavation

AIM

To evaluate the clinical changes in dentin of deep carious lesions in young permanent molars, following ozone application with and without the use of a remineralizing solution, using the stepwise excavation.

STUDY DESIGN

The sample included 162 first permanent immature molars, showing deep occlusal carious cavities that were indicated for indirect pulp capping. Teeth were divided into 2 main groups according to the method of ozone treatment. Each group was further subdivided equally into test and control subgroups. Following caries excavation, color, consistency and DIAGNOdent assessments of dentin were evaluated after 6 and 12 months.

RESULTS

Regarding dentin color and consistency, no significant differences were observed following ozone application, with and without a remineralizing solution. There were no significant differences between ozone treatment, and calcium hydroxide during the different evaluation periods, except in group I cases after 6 months, concerning the dentin color. The DIAGNOdent values were significantly reduced following ozone application, with or without a remineralizing solution, as well as between test and control cases in group I after 6 months.

CONCLUSIONS

Ozone application through the stepwise excavation had no significant effect on dentin color and consistency in young permanent molars. DIAGNOdent was unreliable in monitoring caries activity.

Physicochemical Properties of Epoxy Resin-Based and Bioceramic-Based Root Canal Sealers

Three bioceramic sealers (EndoSequence BC sealer, EndoSeal MTA, and MTA Fillapex) and three epoxy resin-based sealers (AH-Plus, AD Seal, and Radic-Sealer) were tested to evaluate the physicochemical properties: flow, final setting time, radiopacity, dimensional stability, and pH change. The one-way ANOVA and Tukey's post hoc test were used to analyze the data (P = 0.05). The MTA Fillapex sealer had a highest flow and the BC Sealer presented a flow significantly lower than the others (P < 0.05). The BC Sealer and MTA Fillapex samples were not set in humid incubator condition even after one month. EndoSeal MTA had the longest setting time among the measurable materials and Radic-Sealer and AD Seal showed shorter setting time than the AH-Plus (P < 0.05). AH-Plus and EndoSeal MTA showed statistically higher values and MTA Fillapex showed statistically lower radiopacity (P < 0.05). BC Sealer showed the highest alkaline pH in all evaluation periods. Set samples of 3 epoxy resin-based sealers and EndoSeal MTA presented a significant increase of pH over experimental time for 4 weeks. In conclusion, the bioceramic sealer and epoxy resin-based sealers showed clinical acceptable physicochemical properties, but BC Sealer and MTA Fillapex were not set completely.

Power Hydrogen Evaluation of Apexification Materials: EndoCal 10, Mineral Trioxide Aggregate and Calasept Plus

AIM

The present study was to evaluate pH values of apexification materials.

MATERIALS AND METHODS

The materials were placed in 1 cm long and 4 mm diameter tubes. After sample immersion, glass flasks were hermetically sealed with rubber caps to attenuate any effects of external environmental factors and maintained at 37°C. The power hydrogen of the pastes was measured 1 hour, 3 hours, 8 hours, 24 hours, 72 hours and 7 days after preparation. pH was calibrated with solutions of known pH (7.0). Mann-Whitney test were used to determine significant differences.

RESULTS

The mean pH of all medications was < 12.0 throughout the experiment. At 24 hours, EndoCal 10 had the highest pH of all the materials (p < 0.05).

CONCLUSION

According to the results obtained, it may be concluded that calcium oxide (EndoCal 10) presented the highest pH compared with mineral trioxide aggregate (MTA) and Calasept Plus [Ca(OH)2].

CLINICAL SIGNIFICANCE

Apexification is an important treatment in immature teeth. For this reason, used materials in apexification should have some properties, such as high pH and stimulating to be hard tissue. Therefore, the material should be chosen carefully in apexification of immature teeth.

Physical properties of 5 root canal sealers

INTRODUCTION

The aim of this study was to evaluate the pH change, viscosity and other physical properties of 2 novel root canal sealers (MTA Fillapex and Endosequence BC) in comparison with 2 epoxy resin-based sealers (AH Plus and ThermaSeal), a silicone-based sealer (GuttaFlow), and a zinc oxide-eugenol-based sealer (Pulp Canal Sealer).

METHODS

ISO 6876/2001 specifications were followed. The pH change of freshly mixed and set sealers was evaluated during periods of 1 day and 5 weeks, respectively. The viscosity was investigated at different injection rates (72, 10, and 5 mm/min) at room temperature by using a syringe-based system that was based on the Instron 3360 series universal testing system.

RESULTS

The flow, dimensional change, solubility, and film thickness of all the tested sealers were in agreement with ISO 6876/2001 recommendations. The MTA Fillapex sealer exhibited a higher flow than the Endosequence BC sealer (P < .05). The MTA Fillapex and Endosequence BC sealers showed the highest film thicknesses among the tested samples. The Endosequence BC sealer exhibited the highest value of solubility, which was in accordance with 3% mass fraction recommended by the ISO 6876/2001, and showed an acceptable dimensional change. The MTA Fillapex and Endosequence BC sealers presented an alkaline pH at all times. The pH of fresh samples of the AH Plus and ThermaSeal sealers was alkaline at first but decreased significantly after 24 hours. The viscosity of the tested sealers increased with the decreased injection rates.

CONCLUSIONS

The tested sealers were pseudoplastic according to their viscosities as determined in this study. The MTA Fillapex and Endosequence BC sealers each possessed comparable flow and dimensional stability but higher film thickness and solubility than the other sealers tested.

An in vitro Study of Diffusibility and Degradation of Three Calcium Hydroxide Pastes

Aims and objectives : The aim of this in vitro study is to assess the diffusibility and degradation of three calcium hydroxide pastes. Materials and methods : Three pastes were prepared by mixing calcium hydroxide powder with three different vehicles namely water, propylene glycol and CMCP for the investigation. The three pastes were sealed in porcelain caps and immersed in distilled water for the diffusion study. The change in the pH of the surrounding water indicated the rate and degree of diffusion in the degradation study (1 to 7 days, 14th day, 21st day and 30th day). The pastes were exposed to an atmosphere of carbon dioxide in the degradation study to assess the degree to which they can undergo degradation by carbonation. Mordant Black or Solochrome Black indicator was used for the estimation. Results and conclusion : Calcium hydroxide readily diffuses from all the three pastes. Calcium hydroxide diffuses marginally less from a paste made with propylene glycol as compared to CMCP paste. The comparative stability of Ca(OH)2 was studied and the results showed that consistently significant protection is imparted to Ca(OH)2 by CMCP over widely ranging periods.

Calcium hydroxide-based root canal sealers: a review

The aim of this review was to consider laboratory experiments and clinical studies of calcium hydroxide-based root canal sealers. An extensive search of the endodontic literature was made to identify publications related to calcium hydroxide-based root canal sealers. The articles were assessed for the outcome of laboratory and clinical studies on their biological properties and physical characteristics. Comparative studies with other sealers were also considered. Several studies were evaluated covering different properties of calcium hydroxide-based sealers including physical properties, biocompatibility, leakage, adhesion, solubility, antibacterial properties, and periapical healing effect. Calcium hydroxide-based root canal sealers have a variety of physical and biological properties. Comparative studies reveal their mild cytotoxicity, but their antibacterial effects are variable. Further research is required to establish the tissue healing properties of calcium hydroxide in root canal sealers.

Periodontal healing after replantation of intentionally rotated teeth with healthy and denuded root surfaces

The purpose of the study was to evaluate periodontal healing after replantation of intentionally rotated teeth with healthy and denuded root surfaces. Ten teeth with hopeless prognoses because of extensive alveolar bone loss and deep pockets extending to the apexes only on one or two surfaces, but with a healthy periodontal apparatus on the other surfaces, were selected. A mucogingival flap was elevated and the teeth were extracted carefully so as not to damage the healthy remnant of the periodontal membrane remaining on the root surfaces. Thorough extra-oral debridement was performed on the contaminated root surface and the remnant was carefully conserved. Retrofilling was also done to eliminate an endodontic cause of attachment loss. The teeth were horizontally rotated and then replanted so that the healthy root would face the connective tissue at the initially periodontally involved sites, and the root planed surfaces, which had been periodontally involved, would face the surfaces of the alveolar sockets at initially healthy sites. The teeth were splinted with adjacent teeth. Clinical parameters and radiographic examination were performed pre-operatively, and at 3 or 6 months, 1, 2, and 3 years postoperatively. One tooth was extracted 1.5 years postoperatively due to reduced support and the treatment strategy of the patient. The other nine teeth were well maintained without any discomfort for the whole maintenance period of 3 years. In all teeth, areas that previously had no pocketing but were now against denuded root surfaces maintained the previous pocket depth readings. In areas where a deep pocket was present but now had a root surface with healthy periodontium, a distinct decrease of mean pocket depth was observed at the first reexamination 3 months postoperatively. The mean radiographic alveolar bone level increased from 0.3% to 45.3% in 2 years and was thereafter maintained for the entire observation period. Loss of periodontal space and possible root resorption were observed in only one case without other ankylotic symptoms. These results suggest that the healing without ankylosis of an extensive denuded root surface may occur by mechanisms other than the maintenance of a viable periodontal ligament on the root surface.

Calcium hydroxide pastes: classification and clinical indications

REVIEW ARTICLE: Calcium hydroxide has been used in endodontology for many years. The aim of this paper is to review the various formulations of calcium hydroxide that have been described, with specific reference to the vehicle used to carry the compound. The requirements for a vehicle are described, and ex vivo and in vivo studies reviewed. Vehicles can be classified into aqueous, viscous and oily, the clinical properties of calcium hydroxide changing depending on the vehicle. The review also describes the use of various active components that have been added to calcium hydroxide, including antimicrobial and anti-inflammatory agents. This review will help clinicians to make informed judgements about which formulations of calcium hydroxide should be used for specific endodontic procedures.

Apexification: case report

Apexification is a process/procedure well recognized and accepted by clinicians and researchers alike. Calcium hydroxide is most commonly used to induce an apical hard tissue barrier which may be composed of different tissues but its mechanism of action is still unknown. The epithelial cell rests of Malassez have been implicated in apexification although case reports exist which apparently dispute this. The following case report demonstrates an unusual case of apexification following root filling, surgery and retreatment where the role of the epithelial cell rests of Malassez is discussed.

Review of calcium hydroxide

Calcium hydroxide is a material which has been used for a variety of purposes since its introduction into dentistry in the early part of the twentieth century. In its pure form, the substance has a high pH, and its dental use relates chiefly to its ability to stimulate mineralization, and also to its antibacterial properties. A range of products has been formulated with different therapeutic actions, the effects of which are partially dependent upon the tissue to which they are applied. The material is reviewed under the following general headings: biochemical actions; dental formulation; uses.

Multiple external root resorption

Presented is an unusual case of multiple external root resorption. Although the cause of this resorption was not determined, several possibilities are presented. Trauma from occlusion, periodontal and pulpal inflammation, and resorption of idiopathic origin are all discussed as possible causes.