Screening of hydrogel-based scaffolds for dental pulp regeneration-A systematic review.

OBJECTIVE: The aim of this systematic review was to evaluate the most appropriate hydrogel scaffold type (natural, synthetic or hybrid) to be applied with stem cells for dental pulp regeneration. The findings should help clinicians make an informed choice about the appropriate scaffold to be applied for this approach. DESIGN: Three electronic databases were searched (Medline, Web of Science and Scopus). The review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). RESULTS: From 4990 potentially relevant studies initially identified, 18 papers fulfilled the eligibility criteria and were considered for this review. Natural scaffolds were applied in most studies. Collagen was the most studied scaffold. In 5 of 10 studies, only growth factors were added to the constructs. Even without growth factors, these scaffolds containing stem cells were able to support the formation of dentin. The synthetic scaffolds were the least studied. Only 4 studies were selected, and in 3 of them, the same scaffold (Puramatrix) was evaluated. Puramatrix by itself was unable to form dental pulp when dental pulp stem cells were not present. Synthetic and hybrid hydrogels were unable to attract stem cells from the host. The presence of growth factors in these constructs seems to be of relevance since dental pulp tissue formation was achieved only when the hybrid scaffold was applied with growth factors. CONCLUSION: All types of hydrogel-based scaffolds, when containing mesenchymal stem cells, are able to form connective tissue with different degrees of similarity to dental pulp. However, current data is too heterogeneous to compare and identify the advantages of any specific scaffold.

Fracture incidence of instruments from a single-file reciprocating system by students in an endodontic graduate programme: a cross-sectional retrospective study.

AIM: To assess the fracture incidence of instruments from single-file reciprocating systems when used by students in an endodontic graduate programme. METHODOLOGY: Dental records and periapical radiographs of patients treated by students on an endodontic graduate programme using reciprocating systems were assessed. Data on tooth type, number of treated root canals, number of fractured instruments, fragment size, angle, radius, arc length and position of root canal curvature where fractures occurred were tabulated for analysis. The risk of fracture was calculated for each group of teeth, root canal and root thirds, whilst the incidence of fractures reported for the reciprocating systems was compared using the chi-squared test at 5% significance level. RESULTS: Overall, 2056 root canals (826 teeth) from 810 patients were included. The incidence of fractured files from single-file reciprocating systems in relation to a number of instrumented canals was 0.92%. Fracture rates of 0.84% and 0.93% were found in 830 and 1226 root canals instrumented with WaveOne and Reciproc systems, respectively. No significant differences were observed between the systems. The highest fracture rate was 52.6% in the mesiobuccal root of mandibular molars. The central angle, radius and arc length of the curvature of root canals where the instruments fractured ranged from 58° to 84°, from 1.7 to 7.2 mm and from 2.4 to 7.6 mm, respectively. CONCLUSION: The use of WaveOne and Reciproc single-file reciprocating systems in an endodontic graduate programme was associated with a low incidence of instrument fractures.