Mesiobuccal Root Canal Morphology of Maxillary First Molars in a Brazilian Sub-Population - A Micro-CT Study

Objective: This study aimed to investigate the root canal system morphology of maxillary first molar mesiobuccal (MB) roots in a Brazilian sub-population using micro-computed tomography. Methods: Ninety-six MB roots were scanned with a micro-CT (Skyscan 1173, Bruker). Three-dimensional images were analyzed regarding the number of pulp chamber orifices, the number and classification of the canals, the presence of accessory canals in different thirds of the root as well as the number and type of apical foramina. Results: A single entrance orifice was found in 53.0% of the samples, two in 43.9% and only 3.1% had three orifices. The second mesiobuccal root canal (MB2) was present at some portion of the root in 87.5% of the specimens. A single apical foramen was present in 16.7%, two in 22.9%, and three or more foramina in 60.4% of the roots. Only 55.3% and 76.1% of the root canals could be arranged by Weine's and Vertucci's classifications, respectively. Conclusion: The number of orifices at the pulp chamber level could not work as a predictor of the MB2 presence. The most prevalent canal configuration was Weine type IV / Vertucci type V. The anatomical complexity of the MB root could not be entirely classified by the current most accepted classifications.status: publishe

Injectable phosphopullulan-functionalized calcium-silicate cement for pulp-tissue engineering: An in-vivo and ex-vivo study

OBJECTIVE: To evaluate, by means of an ex-vivo human tooth-culture model and in-vivo minipig animal study, the pulpal inflammatory reaction and reparative dentin-formation capacity of an injectable phosphopullulan-based calcium-silicate cement (GC, Tokyo, Japan) upon pulp capping, this in comparison with the commercial reference material Biodentine (Septodont). METHODS: For the ex-vivo tooth model, 9 freshly-extracted teeth from 3 different patients were pulp-capped with the experimental biomaterial (n = 3), Biodentine (n = 3) or left uncapped (control; n = 3). The teeth were kept in fresh culture medium for 4 weeks and, upon fixation three-dimensional Micro-CT and histology were performed. For the in-vivo animal study, 40 teeth from 3 minipigs were exposed and pulp capped with the experimental biomaterial containing phosphopullulan (n = 24) or Biodentine (n = 16) for 7 or 70 days. The inflammatory reaction and the tissue-regenerative potential was qualitatively and semi-quantitatively characterized using three-dimensional micro-CT and histology. RESULTS: Ex vivo, the treatment with the experimental phosphopullulan-based calcium-silicate cement and Biodentine stimulated the formation of fibrous tissue and mineralized foci. In vivo, early inflammatory reaction and regeneration of the pulp-tissue interface was promoted by both bioceramic materials after 7 and 70 days, respectively. SIGNIFICANCE: Our findings bring new insights into calcium-silicate-mediated dental pulp repair and regeneration. The novel ready-to-use and self-adhering functionalized calcium-silicate cement revealed effective pulpal repair potential.status: publishe

Preclinical effectiveness of an experimental tricalcium silicate cement on pulpal repair

OBJECTIVES: To investigate the pulpal repair potential of an experimental zirconium-oxide containing tricalcium-silicate cement, referred to as 'TCS 50'. MATERIALS AND METHODS: The effect of TCS 50 on viability, proliferation, migration, and odontoblastic differentiation of human dental pulp cells (HDPCs) was assessed using XTT assay, in-vitro wound healing assay and RT-PCR, respectively. Additionally, the pulp-capping potential was evaluated using a vital human tooth model. Statistical analysis was performed using non-parametric Kruskal-Wallis test and post-hoc test (Mann-Whitney U test). The tests were performed at a significance level of α = 0.05. RESULTS: The effect of TCS 50 towards HDPCs was dose dependent. Undiluted TCS 50 extract showed no immediate adverse impact on cell viability (p > .05); however, it significantly inhibited proliferation and migration of HDPCs (p  .05), and it significantly enhanced odontoblastic differentiation of HDPCs (p < .05). In pulps capped with TCS 50 for both 2 and 4 weeks, H&E staining revealed a normal morphology of pulp tissue; mineralized foci with cellular components entrapped in the matrix were formed underneath the exposure site. Collagen I expression was weak within the matrix of mineralized foci, while the expression of nestin was positive for entrapped cellular components within the mineralized foci, indicating that the formed mineralized foci corresponded to an initial form of reparative dentin formation. CONCLUSION: TCS 50 is capable of generating an early pulp-healing reaction and therefore could serve as a promising pulp-capping agent.status: publishe

Experimental tricalcium silicate cement induces reparative dentinogenesis

OBJECTIVES: To overcome shortcomings of hydraulic calcium-silicate cements (hCSCs), an experimental tricalcium silicate (TCS) cement, named 'TCS 50', was developed. In vitro research showed that TCS 50 played no negative effect on the viability and proliferation of human dental pulp cells, and it induced cell odontogenic differentiation. The objective was to evaluate the pulpal repair potential of TCS 50 applied onto exposed minipig pulps. METHODS: Twenty permanent teeth from three minipigs were mechanically exposed and capped using TCS 50; half of the teeth were scheduled for 7-day and the other half for 70-day examination (n=10). Commercial hCSCs ProRoot MTA and TheraCal LC were tested as references (n=8). Tooth discoloration was examined visually. After animal sacrifice, the teeth were scanned using micro-computed tomography; inflammatory response at day 7 and day 70, mineralized tissue formation at day 70 were assessed histologically. RESULTS: Up to 70 days, TCS 50 induced no discoloration, ProRoot MTA generated gray/black discoloration in all teeth. For TCS 50, 40.0% pulps exhibited a mild/moderate inflammation at day 7. No inflammation was detected and complete reparative dentin with tubular structures was formed in all pulps after 70 days. ProRoot MTA induced a similar response, TheraCal LC generated a less favorable response in terms of initial inflammation and reparative dentin formation; however, these differences were not significant (Chi-square test of independence: p>0.05). SIGNIFICANCE: TCS 50 induced reparative dentinogenesis in minipig pulps. It can be considered as a promising pulp-capping agent, also for aesthetic areas.status: publishe