No abstract

Utilization efficiency (LUE) of lightflecks by leaves increases with decreasing duration of the lightfleck, and depends on photosynthetic induction. Sun and shade leaves differ with respect to photosynthetic induction. Shade leaves may become fully induced by a series of light pulses, whereas photosynthetic induction of leaves from partial shade or full sun depends on continuous light. Additionally, shade leaves maintain a higher induction state over longer periods in dim light or darkness than sun leaves. Both features are advantageous to shade leaves in a highly dynamic light environment. We determined whether pioneer plants and late-successional species differ in photosynthetic induction dynamics and LUE during the establishment phase when both plant types are growing in the shade of the understory. We also determined the effects of shade acclimation and successional position of species on photosynthetic induction and LUE. Results from temperate and tropical rain forests indicate a trade-off between leaf acclimation to shade and the successional position of species. Light acclimation is important, but in deep shade, late-successional species maintain a higher induction state over longer periods than pioneer species.

BackgroundMany adolescents have poor plaque control and sub-optimal toothbrushing behavior. Therefore, we compared the efficacy of an interactive power toothbrush (IPT) to a manual toothbrush (MT) for reducing dental plaque and improving toothbrushing compliance.MethodsIn this randomized, parallel single-blind clinical study, adolescents brushed twice daily with either a MT (Oral-B® Indicator soft manual toothbrush) or an IPT (Oral-B® ProfessionalCare 6000 with Bluetooth). Subjects brushed for 2 min, plus an additional 10 s for each ‘Focus Care Area’. At screening and Week 2, afternoon pre-brushing plaque was assessed via the Turesky Modification of the Quigley-Hein Plaque Index (TMQHPI), and supervised brushing duration was measured.ResultsSixty subjects were randomized; 98% completed. At Week 2, the mean reduction in whole mouth plaque relative to baseline was 34% (p < 0.001) for the IPT versus 1.7% (p = 0.231) for the MT. For Focus Care Areas, the IPT yielded a 38.1% mean TMQHPI reduction (p < 0.001) versus 6.2% for the MT (p < 0.001). Mean brushing time versus baseline increased 34 s in the IPT group (p < 0.001) while remaining flat in the MT group (p = 1.0).ConclusionsOver 2 weeks, adolescents using an IPT experienced superior plaque reduction and increased overall brushing time versus those using a MT.Trial registrationThis trial was retrospectively registered (ISRCTN10112852) on the 18th, June 2018.

A randomized clinical trial comparing plaque removal efficacy of an oscillating-rotating power toothbrush to a manual toothbrush by multiple examiners Abstract: Objective: To determine whether multiple examiners can demonstrate consistent plaque removal advantages for an oscillatingrotating power toothbrush versus a manual toothbrush. Methods: This was a replicate-use, single brushing, examiner-blind, randomized, two-treatment, four-period crossover clinical trial involving four examiners. Subjects were randomized to one of four treatment sequences involving two toothbrushes: an oscillating-rotating power toothbrush or a manual toothbrush. At each of the four visits, subjects arrived having abstained from oral hygiene for 24 h prior, and brushed with their assigned toothbrush and a marketed fluoride dentifrice under supervision unaided by a mirror. Plaque was assessed by each examiner using the Turesky-Modified Quigley-Hein Plaque Index at each study period before and after brushing. Data was analysed separately for each examiner using the analysis of covariance for crossover design. Results: Ninety-five subjects between the ages of 18 and 70 met the entrance criteria and were enrolled in the study. Eighty-seven subjects completed all four periods of the study. Both brushes delivered a significant plaque reduction when compared to baseline. Significant treatment differences were observed for all four examiners -ranging from 0.10 to 0.16 -in favor of the oscillating-rotating brush (P < 0.001). There were no adverse events reported or observed for either brush. Conclusions: All four examiners demonstrated the power toothbrush removed significantly more plaque after a single brushing than the standard manual toothbrush. Both brushes were well tolerated.

Background. Clinical investigations of plaque removal efficacy of power toothbrushes in children are limited. Aim. To compare plaque removal of a power versus manual toothbrush in a paediatric population. Design. This was a randomised, replicate-use, single-brushing, examiner-blinded, two-treatment, four-period crossover clinical trial in children 8-11 years of age. Subjects were randomly assigned to a treatment sequence involving an oscillating-rotating power toothbrush and a manual toothbrush control. Subjects brushed under supervision with a NaF dentifrice. Plaque was assessed pre-(baseline) and post-brushing using the Turesky Modification of the Quigley-Hein Plaque Index by two examiners. Plaque scores were averaged for mixed and permanent dentition on a per-subject basis and analysed using a mixed-model ANCOVA for a crossover design. Results. Forty-one subjects (mean 9.0 years) were randomised and completed the trial. Both the power brush and manual brush provided statistically significant mean plaque reductions versus baseline in all analyses (P < 0.001). For both examiners, plaque removal was significantly (P < 0.001) larger for the power brush in permanent and mixed dentitions. The interexaminer correlations for the permanent dentition were strong (ICC = 0.68-0.88) for pre-brushing plaque across all periods.Conclusions. An oscillating-rotating power toothbrush provided superior plaque reduction versus a manual toothbrush in children.