The in vitro remineralizing effect of CPP-ACP and CPP-ACPF after 6 and 12 weeks on initial caries lesion

Objective: The aim of this in vitro study was to determine the effects of remineralization promoting agents containing casein phosphopeptidestabilized amorphous calcium phosphate (CPP-ACP), or CPP-ACP in combination with fluoride (CPP-ACPF) on artificial white spot lesions (WSLs) after 6 and 12 weeks. Methodology: White spot lesions were created on 123 sectioned premolars (246 specimens) with a demineralization solution during a 96 hours pH-cycling regime. Two experimental groups were created: a CPP-ACP group (Tooth MousseTM), and a CPP-ACPF group (Mi Paste PlusTM). Additionally, two control groups were created, one using only a conventional toothpaste (1450 ppm fluoride) and another one without any working agents. All teeth were also daily brushed with the conventional toothpaste except the second control group. Tooth MousseTM and Mi Paste PlusTM were applied for 180 seconds every day. The volume of demineralization was measured with transverse microradiography. Six lesion characteristics regarding the lesion depth and mineral content of WSLs were also determined. Results: The application of CPP-ACP and CPP-ACPF had a significant regenerative effect on the WSLs. Compared to Control group 1 and 2 the volume of demineralization after 6 weeks decreased significantly for CPP-ACP (respectively p<0.001 and p<0.001) and CPP-ACPF (respectively p=0.001 and p=0.003). The same trend was observed after 12 weeks. For the CPP-ACPF group, WSL dimensions decreased significantly between 6 and 12 weeks follow-up (p=0.012). The lesion depth reduced significantly after application of CPP-ACP and CPP-ACPF but increased significantly in the Control groups. Mineral content increased for CPP-ACP and CPP-ACPF after an application period of 12 weeks, but this was only significant for CPP-ACP. Conclusions: Long-term use of CPP-ACP and CPP-ACPF in combination with a conventional tooth paste shows beneficial effects in the recovery of in vitro subsurface caries lesions

vrp-1 regulates Yolk Protein Production in Caenorhabditis elegans

status: publishe

An esthetic evaluation of unilateral canine substitution for a missing maxillary lateral incisor

Objectives: The aim of this study is to determine whether variation in size, morphology, and color of a unilateral substituted maxillary canine has influence on the dentogingival attractiveness perceived by dental professionals and laypeople. Materials and Methods: A frontal clinical photograph of a patient with unilateral canine substitution was used as standard picture. Five different series were created by modification of following parameters with a raster graphics editor (Photoshop CS 6): (1) width, (2) color, (3) gingival margin height, and (4) crown tip morphology of the substituted canine and (5) the gingival margin height of the neighboring first premolar. For each parameter, the photograph deviating the most from the standard photograph, was combined into a final series. Four groups of examiners (orthodontists, periodontists, dentists, and laypeople) were asked to rank the photographs from most to least attractive. Results: One hundred seventy-four examiners ranked the photographs in order of attractiveness. Overall, a darker canine color (mean rank 4.361.03) and a more pronounced canine tip morphology (mean rank 3.471.11) were significantly ranked as most unattractive (P<.05). The gingival height of the neighboring premolar was ranked as least unattractive by all groups of examiners (mean rank 1.30 +/- 0.74). Conclusions: Darker canine color and a pronounced tip morphology of a substituted canine are rated as the most unattractive by dental professionals and laypeople. CLINICAL SIGNIFICANCE: The present study showed that the canine color and crown tip morphology are important parameters when considering unilateral canine substitution, both for professionals and laypeople. There is a general preference in favor of canines with a light color and a reduced incisal tip

Computational assessment of the deployment of bistable scissor structures

Preassembled scissor structures are transportable and can be transformed rapidly while offering a huge volume expansion. Intended geometrical incompatibilities between the members during transformation can be introduced as a design strategy to obtain bistability, which allows instantaneously achieving some structural stability in the deployed state. In such bistable scissor structures, these incompatibilities result in the bending of some specific members that are under compression with a controlled snap-through behavior. This contribution investigates the nonlinear structural behavior of bistable scissor structures during transformation using finite element models. Attempts to model the complete transformation cycle of bistable scissor structures remain scarce, partially because the underlying phenomena and modeling concepts are complex. The main goal of this contribution is to propose a 3D nonlinear structural model for the simulation of the deployment of bistable scissor structures including geometrical imperfections.info:eu-repo/semantics/publishe