Calcium chloride-enriched calcium aluminate cement promotes in vitro osteogenesis.

AIM: To evaluate the effects of 2.8% or 10% calcium chloride (CaCl2 ) in calcium aluminate cement (CAC) with either bismuth oxide (Bi2 O3 ) or zinc oxide (ZnO) as radiopacifiers on the progression of osteogenic cell cultures. METHODOLOGY: Rat calvaria-derived cells were grown on Thermanox® coverslips for 24 h and exposed to samples of (i) CACb: with 2.8% CaCl2 and 25% Bi2 O3 ; (ii) CACb+: with 10% CaCl2 and 25% Bi2 O3 ; (iii) CACz: with 2.8% CaCl2 and 25% ZnO; or (iv) CACz+: with 10% CaCl2 and 25% ZnO, placed on inserts. Nonexposed cultures served as the control. Calcium and phosphorus contents in culture media were quantified. The effects of the cements on cell apoptosis, cell viability and acquisition of the osteogenic cell phenotype were evaluated. Data were compared by Kruskal-Wallis test (α = 5%). RESULTS: CACb+ promoted the highest levels of calcium in the culture media; CACz+, the lowest levels of phosphorus (P < 0.05). CACz+ and CACb increased cell apoptosis (P < 0.05). CACb reduced cell viability (P < 0.05) and the expression of the osteoblastic phenotype. CACz+ and CACb+ promoted greater cell differentiation and matrix mineralization compared to CACz and CACb (P < 0.05). CONCLUSION: For CAC with the lower CaCl2 content, the use of Bi2 O3 was detrimental for osteoblastic cell survival and differentiation compared to ZnO, while CAC with the higher CaCl2 content supported the acquisition of the osteogenic cell phenotype in vitro regardless of the radiopacifier used. Thus, CAC with 10% CaCl2 would potentially promote bone repair in the context of endodontic therapies.

Osteogenic cell response to calcium aluminate-based cement.

AIM: To evaluate the effect of a calcium aluminate-based cement (CAC+) on the development of the osteogenic phenotype in vitro. METHODOLOGY: Rat calvaria-derived cells were grown on Thermanox® coverslips for 24 h and then exposed to either samples (4-h set) of CAC+ or mineral trioxide aggregate (MTA) placed on Transwell® inserts for periods of up to 14 days. Nonexposed cultures were used as the controls. The comparisons were made using the nonparametric Kruskal-Wallis test, followed by the Student-Newman-Keuls post hoc test when appropriate. RESULTS: The results showed that proximity to MTA or CAC+ samples inhibited cell growth, whereas at a distance, viable and proliferative cells adhered to and spread on the Thermanox® , expressing osteoblast differentiation markers prior to mineralization of the extracellular matrix. Compared with MTA, the osteogenic cell cultures exposed to CAC+ exhibited significantly greater cell viability, alkaline phosphatase (ALP) activity and expression of runt-related transcription factor 2, osterix, ALP, bone sialoprotein and osteocalcin (P < 0.05 for all). For the osteogenic cell cultures exposed to CAC+, the quantification of matrix mineralization was not altered (P > 0.05). CONCLUSIONS: CAC+ supported the acquisition of the osteogenic cell phenotype in vitro, rendering this novel material a potential alternative to MTA in endodontic procedures. Further in vivo studies are needed to verify if the beneficial in vitro effects of CAC+ on osteoblastic cells correspond to an increase and/or acceleration of bone repair in the periapical region.

Chemical, physical and mechanical properties of a novel calcium aluminate endodontic cement.

AIM: To evaluate the influence of additives on several physical and chemical properties of a novel endodontic cement based on calcium aluminate in comparison with mineral trioxide aggregate (MTA). METHODOLOGY: Manipulation tests, measurements of temperature, pH, ionic conductivity, compressive strength, apparent porosity, and pore size distribution were carried out on Gray-MTA (Angelus) and calcium aluminate cement (Secar-71, Kerneos) with and without various additives: a polymeric dispersant, CaCl(2) as plasticizer, and ZnO as radiopacifier. RESULTS: The calcium aluminate cement without additives had a setting time of approximately 60min, and when combined with Li(2) CO(3) it decreased to 10min. The material also released Ca(2+) ions and alkalinized the medium. Moreover, the addition of additives (dispersant, plasticizer, and radiopacifier) improved its properties resulting in a material with a viscosity of 57mPas, enhanced handling properties, a mechanical strength of 81MPa, a porosity of 4% and pores with small diameter (0.25µm). MTA had no temperature increase (that indicates setting) up to 400min, a mechanical strength of 34MPa, and porosity of 28% with pores 2.5µm in diameter. CONCLUSION: The novel cement set more rapidly, had better fluidity, improved handling properties, higher mechanical strength, and reduced porosity with lower pore size compared to Gray-MTA Angelus.

Treatment of inflammatory internal root resorption with mineral trioxide aggregate: a case report.

AIM: To report the treatment and follow-up of a maxillary central incisor with internal resorption managed by root canal treatment, white mineral trioxide aggregate (MTA) repair and a fibre-glass post for reinforcement. SUMMARY: This study presents a case of extensive internal root resorption affecting tooth 11 (FDI) in a 28-year-old male patient, with a history of trauma in that region. The substantial loss of tooth structure, including cementum, and a perforation with lateral periodontal communication were complicating factors. Despite a guarded prognosis but encouraged by a healthy periodontal condition, treatment based on reconstructing the tooth with white MTA and a fibre-glass core was carried out. Follow-up radiographs over 20 months demonstrated the maintenance of a functional tooth. The tooth did, however, discolour after MTA treatment. KEY LEARNING POINTS: Because of its insidious pathology, internal root resorption can extend to significant dimensions before being recognized. MTA plus the fitting of a fibre-glass post provided adequate, functional rehabilitation of a compromised tooth for 20 months. Despite the favourable biological and mechanical properties of white MTA, considerable tooth discolouration may occur.