Regeneration of pulp-dentin complex using human stem cells of the apical papilla: in vivo interaction with two bioactive materials.

OBJECTIVES: To compare the regenerative properties of human stem cells of the apical papilla (SCAPs) embedded in a platelet-rich plasma (PRP) scaffold, when implanted in vivo using an organotypic model composed of human root segments, with or without the presence of the bioactive cements - ProRoot MTA or Biodentine. MATERIAL AND METHODS: SCAPs were isolated from third molars with incomplete rhizogenesis and expanded and characterized in vitro using stem cell and surface markers. The pluripotency of these cells was also assessed using adipogenic, chondrogenic, and osteogenic differentiation protocols. SCAPs together with a scaffold of PRP were added to the root segment lumen and the organotypic model implanted on the dorsal region of immunodeficient rats for a period of 4 months. RESULTS: Presence of SCAPs induced de novo formation of dentin-like and pulp-like tissue. A barrier of either ProRoot MTA or Biodentine did not significantly affect the fraction of sections from roots segments observed to contain deposition of hard material (P > 0.05). However, the area of newly deposited dentin was significantly greater in segments containing a barrier of Biodentine compared with ProRoot MTA (P < 0.001). CONCLUSIONS AND CLINICAL RELEVANCE: SCAPs offer a viable alternative to other dental stem cells (DSCs) in their regenerative properties when enclosed in the microenvironment of human tooth roots. The present study also suggests that the presence of bioactive materials does not hinder or impede the formation of new hard tissues, but the presence of Biodentine may promote greater mineralized tissue deposition.

Collagenated Porcine Heterologous Bone Grafts: Histomorphometric Evaluation of Bone Formation Using Different Physical Forms in a Rabbit Cancellous Bone Model.

Collagenated porcine-derived bone graft materials exhibit osteoconductive properties and the development of different formulations intends to enhance bone regeneration. This study aims to evaluate bone healing in a rabbit cancellous bone defect in response to grafting with different physicochemical forms of heterologous porcine bone. Twenty-six adult male New Zealand White rabbits received two critical size femoral bone defects per animal (n = 52), each randomly assigned to one of the five tested materials (Apatos, Gen-Os, mp3, Putty, and Gel 40). Animals were sacrificed at 15- and 30-days post-surgery. Qualitative and quantitative (new bone, particle and connective tissue percentages) histological analyses were performed. Histomorphometry showed statistically significant differences in all evaluated parameters between mp3 and both Putty and Gel 40 groups, regardless of the timepoint (p < 0.05). Moreover, statistical differences were observed between Apatos and both Putty (p = 0.014) and Gel 40 (p = 0.007) groups, at 30 days, in regard to particle percentage. Within each group, regarding new bone formation, mp3 showed significant differences (p = 0.028) between 15 (40.93 ± 3.49%) and 30 (52.49 ± 11.04%) days. Additionally, intragroup analysis concerning the percentage of particles revealed a significant reduction in particle occupied area from 15 to 30 days in mp3 and Gen-Os groups (p = 0.009). All mp3, Gen-Os and Apatos exhibited promising results in terms of new bone formation, thus presenting suitable alternatives to be used in bone regeneration.

Therapeutic letters: A qualitative study exploring their influence on the hope of parents of children receiving pediatric palliative care in Portugal.

PURPOSE: The purpose of this qualitative descriptive study was to explore the hope experiences of parents of children diagnosed with complex chronic conditions (CCCs) who received therapeutic letters. DESIGN AND METHODS: A purposive sample of 10 parents of inpatient children with CCCs was recruited from a pediatric palliative care unit in a Portuguese public hospital. A demographic form and audio-recorded semi-structured, face-to-face interviews were conducted with each participant to explore the experiences, processes, and meanings of hope, and to describe how parents of children receiving pediatric palliative care perceived the usefulness of receiving therapeutic letters. The interviews were transcribed verbatim, and using a thematic analysis, a systematic approach to data analysis was completed. FINDINGS: Data analysis resulted in three main themes including Trust in the Future; Strengthening Hope; and Moments of Hope. Findings highlight the positive influence of therapeutic letters including supporting parental hope, facilitating personal inner-strengthening, recognition of parental skills, and promotion of self-efficacy during hospitalization. The themes and related subthemes add value to the existing literature and highlight the need for supportive palliative nursing care aimed at promoting parental hope. PRACTICE IMPLICATIONS: To optimize the value of supporting parental hope, therapeutic letters can be delivered at the time of diagnosis, during times of celebration, and when learning the difficult tasks of daily childcare. Additional research can inform the development of a formal hope-based intervention to provide an evidence base from which to enhance the well-being of parental caregivers of children who have CCCs.

Histologic Evaluation of Regenerative Endodontic Procedures with the Use of Chitosan Scaffolds in Immature Dog Teeth with Apical Periodontitis.

INTRODUCTION: The aim of this study was to evaluate histologically the newly formed tissues after regenerative endodontic procedures (REPs) in dogs using either a blood clot (BC) or 2 different formulations of a chitosan hydrogel as scaffolds. METHODS: Apical periodontitis was induced by inoculating immature teeth with oral plaque in 4 beagle dogs. Teeth (n = 96) were divided into 2 control (n = 20) and 4 test groups (n = 76) according to the treatment: apexification and REPs with BC, sodium hyaluronate:chitosan (HA:CS) scaffolds, or pectin:chitosan (P:CS) scaffolds. All root canals were disinfected with 2.5% sodium hypochlorite and a triple antibiotic paste intracanal medicament before evoked bleeding, clot formation, or scaffold placement. Thirteen weeks after treatment, the animals were sacrificed and the jaw blocks harvested for histologic processing, histomorphometric analysis, and statistical analysis. RESULTS: The lumens of the root canals were completely filled with mineral trioxide aggregate with evidence of a mineralized apical bridge between the root canal walls in 83% of the samples in the apexification group. Vital vascularized tissue was found in the REP groups; apical closure happened in 66.7% of these treatments, and root growth was detected more often as an increase in thickness (85.6%) than in length (45.6%). The greatest amount of mineralized tissue inside the canal was observed in the BC group, with statistical significance compared with the HA:CS and P:CS groups (P < .05). Further histologic evaluation revealed the presence of apical papilla. CONCLUSIONS: The addition of chitosan scaffolds to blood in regenerative procedures in dogs did not improve the formation of new mineralized tissues along the root canal walls or the histologic evidence of the regeneration of a pulp-dentin complex.