Umeå University's logo

Aim: To compare differences in the disinfection efficacy of calcium hydroxide (CH) and chlorhexidine gluconate (CHD) dressings in pulp revitalization (PR) of traumatized immature necrotic teeth; to investigate the microflora in successful/failed PR and whether bacterial persistence influences the outcomes of PR.

Methods: Microbiological assessment of the average bacterial load (CFU/sample) and bacterial diversity (taxa/sample) was performed on 41 teeth at three timepoints (S2-before, S3-after debridement and S5- after root canal dressing).

Results: The primary microflora was more diverse in successful cases than in failed. Decreases in CFU/sample and taxa/sample occurred S2 - S3, though new increases occurred at S5 in the CHD subgroup (successful and failed) and CFU/sample in the CH subgroup (failed). At S5, the successful cases showed more bacterial decreases. No specific species was associated with the outcomes with no statistical differences between the disinfection efficacy.

Conclusions: There were no statistical differences in CH and CHD efficacy. At S5, microflora persisted in both successful and failed outcomes, but the abundance and diversity increased significantly only in the failed cases. The successful outcomes presented higher diversity and higher decreases of the primary microflora at S5 than the failed outcomes. The abundance and diversity increased significantly at S5 only in failed cases.

The boreal forest ecosystems of the northern hemisphere are dominated by conifers, of which Norway spruce (Picea abies [L.] H. Karst.) is one of the most common species. Due to its economic interest to the agroforestry industry, as well as its ecological significance, it is important to understand seasonal growth and biomass production in Norway spruce. Solid evidence that the circadian clock regulates growth in conifers has proved elusive, however, resulting in significant gaps in our knowledge of clock function in these trees. Here, we reassess the impact of the circadian clock on growth in Norway spruce. Using a combination of approaches monitoring the physiology of vegetative growth, transcriptomics and bioinformatics, we determined that the clock could be playing a decisive role in enabling growth, acting in specific developmental processes influenced by season and geographical location to guide bud burst and growth. Thus, the evidence indicates that there is time for spruce.

This study investigates the role of the circadian clock in the regulation of gibberellin (GA) metabolism and growth in hybrid aspen (Populus tremula x P. tremuloides (Ptt)). We revealed a conserved function of the clock homolog PttEARLY BIRD1 (PttEBI1), but also implicated its rolein controlling tree growth. GA metabolite profiling and transcriptomic analysis in hybrid aspenlines with modulated expression of PttEBI1 or the core clock homologs PttLATE ELONGATED HYPOCOTYLs (PttLHYs) revealed significant changes in GA metabolism. These alterations werelinked to the differential expression of PttGA2ox8, a gene encoding an enzyme with both GA2-oxidase and GA20-oxidase activities. Our results indicate that modifications to circadian clockcomponents can significantly influence both GA metabolism and tree growth, providing potential strategies for improving tree biomass production.