Influence of varying titanium base abutment heights on retention of zirconia restorations: An in vitro study.

STATEMENT OF PROBLEM: Implant manufacturers have introduced titanium base (Ti-Base) abutments with increased abutment heights, ostensibly, to increase the retention of the bonded restoration and to improve overall strength. However, evidence regarding the effects of increasing Ti-Base height on improving retention is lacking. PURPOSE: The purpose of this in vitro study was to evaluate the effect of different Ti-Base abutment heights on the retention of zirconia implant-supported crowns. MATERIAL AND METHODS: Thirty Ti-Base abutments of the same diameter and heights of 3.5 mm (n=10), 4.5 mm (n=10), and 5.5 mm (n=10), were used for testing. Zirconia restorations were cemented onto the Ti-Base abutments with a resin cement after treatment with a 10-methacryloyloxydecyl dihydrogen phosphate primer by a single operator using a positioning device. The zirconia-Ti-Base restorations were tightened to an implant analog embedded in an autopolymerizing resin block. The specimens were placed and tested in a universal testing machine for pull-out testing. Retention was measured by recording the force at load drop. Statistical analysis was performed using 1-way analysis of variance with the Tukey method for pairwise comparisons. RESULTS: The abutment height had a significant effect on retention (P=.010). Ti-Base abutments of 4.5 and 5.5 mm had significantly greater retention than Ti-Base abutments of 3.5 mm (P=.020, P=.040, respectively). However, Ti-Base abutments of 4.5 and 5.5 mm in height were statistically similar (P=.890). CONCLUSIONS: An increase in the height of Ti-Base abutments above the standard 3.5 mm height significantly improved the retention of the overlying restoration.

Improving Palliative Care and Medical Assistance in Dying Practice in Canada: How Patients-Partners Could Contribute to Continuing Medical Education.

Medical Assistance in Dying (MAiD) is still considered an evolving practice in Canada. Practitioners are facing the challenge of staying up to date and hence need efficient continuing medical education (CME). A patient-partner has been recently invited as a keynote speaker to CME activities in Canada to share her perspectives and views about patient engagement in palliative care and MAiD practice, calling for compassion. To our knowledge, few data exist on patient-partners' contribution to CME on these topics. Based on that experience, we discuss different issues on patient engagement's contribution in such CME events and call for further research.

Efficacy of a novel post-foaming dental gel on gingival inflammation: A randomized controlled clinical trial.

BACKGROUND: A pilot randomized controlled clinical trial was performed to evaluate the efficacy of a post-foaming dental gel containing cetylpridinium chloride (CPC), hydrogen peroxide (H2 O2 ), sodium bicarbonate, and antioxidants on periodontal/oral health. METHODS: Individuals with gingivitis or mild-moderate periodontitis (n=36) were included and randomly assigned to Group 1 and 2 with foaming gel loaded on a mouthpiece with a light source and controlled warming heat built-in unit or on a toothbrush, respectively, in addition to regular twice-daily brushing. Group 3 served as control with twice daily brushing and further assigned split-mouth to Group 3a-un-flossed and Group 3b-flossed. Gingival index (GI) and bleeding on probing (BOP) were evaluated in addition to plaque index (PI), pocket depth, and clinical attachment level at days 14, 28, 42 (treatment), and 60 (maintenance). Subgingival plaque microbial profiles and gingival crevicular fluid (GCF) cytokine levels were determined by DNA-DNA hybridization and multiplexing assays, respectively. Exploratory analyses included esthetic outcomes: changes in tooth color and levels of volatile sulfur compounds in breath. Statistical analyses were conducted using ANOVA with a post hoc analysis of Fisher's LSD. RESULTS: Use of post-foaming gel in both test groups resulted in significant changes in GI and BOP at Day 42 compared to control and un-flossed control (P<0.05). Device-enhanced foaming gel significantly reduced the PI in Group 1 at Day 42 compared to control and un-flossed control (P=0.02; P=0.007, respectively). GCF IL-6 and TNF-α levels were significantly reduced in Group 2 compared to control (PIL-6 =0.01, PTNF-α =0.02). Post-foaming gel resulted in greater reductions in periodontopathogens, whereas health-associated species remained stable. Despite cessation of adjunct treatments, Group 1 and 2 continued having reduced levels of GI, BOP, and PI at Day 60 (P<0.05). CONCLUSIONS: The novel post-foaming dental gel improves oral health by reducing gingival inflammation at the local site in addition to better esthetic outcomes.

Assessment of the Silver Penetration and Distribution in Carious Lesions of Deciduous Teeth Treated with Silver Diamine Fluoride.

The aim of this study was to determine the effects of 38% silver diamine fluoride (SDF) on carious lesions of human deciduous teeth. Ten extracted deciduous incisors with caries were collected and treated with SDF. After the treatment, the teeth were sectioned through the center of the carious lesion. The extent of sliver precipitation was examined using quantitative backscattered electron scanning electron microscopy (qBSE-SEM), energy-dispersive X-ray spectroscopy (EDX), and micro-computed tomography (micro-CT). The qBSE-SEM images revealed that the silver particles could penetrate through the pellicle complex, along with the rod sheaths into the demineralized enamel rods and the dentinal tubules, and form silver-enriched barriers surrounding the carious lesions at depths up to 2,490.2 µm (mean 744.7 ± 448.7 µm) within the dentinal tubules of the carious lesions, but less likely in the sound enamel. The EDX spectrum analysis revealed that carbon, oxygen, phosphorus, chlorine, silver, and calcium were the main elements detected in the lesions treated with SDF. Additionally, sodium, magnesium, aluminum, silicon, zinc, sulfur, and fluorine were detected as the minor elements within the SDF precipitation "zone." The micro-CT analysis further showed that in the deep cavitated lesions, the silver precipitation could be observed in the pulp chamber. These findings provide new evidence defining the SDF mode of action for arresting caries and suggest that the application of a highly concentrated SDF solution on deciduous teeth should be used with caution for various carious lesions.

Dopamine D1 receptor agonist treatment attenuates extinction of morphine conditioned place preference while increasing dendritic complexity in the nucleus accumbens core.

The dopamine D1 receptor (D1R) has a role in opioid reward and conditioned place preference (CPP), but its role in CPP extinction is undetermined. We examined the effect of D1R agonist SKF81297 on the extinction of opioid CPP and associated dendritic morphology in the nucleus accumbens (NAc), a region involved with reward integration and its extinction. During the acquisition of morphine CPP, mice received morphine and saline on alternate days; injections were given immediately before each of eight daily conditioning sessions. Mice subsequently underwent six days of extinction training designed to diminish the previously learned association. Mice were treated with either 0.5mg/kg SKF81297, 0.8mg/kg SKF81297, or saline immediately after each extinction session. There was a dose-dependent effect, with the highest dose of SKF81297 attenuating extinction, as mice treated with this dose had significantly higher CPP scores than controls. Analysis of medium spiny neuron morphology revealed that in the NAc core, but not in the shell, dendritic arbors were significantly more complex in the morphine conditioned, SKF81297-treated mice compared to controls. In separate experiments using mice conditioned with only saline, SKF81297 administration after extinction sessions had no effect on CPP and produced differing effects on dendritic morphology. At the doses used in our experiments, SKF81297 appears to maintain previously learned opioid conditioned behavior, even in the face of new information. The D1R agonist's differential, rather than unidirectional, effects on dendritic morphology in the NAc core suggests that it may be involved in encoding reward information depending on previously learned behavior.

Impact of resolvin E1 on murine neutrophil phagocytosis in type 2 diabetes.

Diabetic complications involve inflammation-mediated microvascular and macrovascular damage, disruption of lipid metabolism, glycosylation of proteins, and abnormalities of neutrophil-mediated events. Resolution of inflamed tissues to health and homeostasis is an active process mediated by endogenous lipid agonists, including lipoxins and resolvins. This proresolution system appears to be compromised in type 2 diabetes (T2D). The goal of this study was to investigate unresolved inflammation in T2D. Wild-type (WT) and genetically engineered mice, including T2D mice (db/db), transgenic mice overexpressing the human resolvin E1 (RvE1) receptor (ERV1), and a newly bred strain of db/ERV1 mice, were used to determine the impact of RvE1 on the phagocytosis of Porphyromonas gingivalis in T2D. Neutrophils were isolated and incubated with fluorescein isothiocyanate-labeled P. gingivalis, and phagocytosis was measured in a fluorochrome-based assay by flow cytometry. Mitogen-activated protein kinase (MAPK) (p42 and p44) and Akt (Thr308 and Ser473) phosphorylation was analyzed by Western blotting. The mouse dorsal air pouch model was used to evaluate the in vivo impact of RvE1. Results revealed that RvE1 increased the neutrophil phagocytosis of P. gingivalis in WT animals but had no impact in db/db animals. In ERV1-transgenic and ERV1-transgenic diabetic mice, phagocytosis was significantly increased. RvE1 decreased Akt and MAPK phosphorylation in the transgenic animals. In vivo dorsal air pouch studies revealed that RvE1 decreases neutrophil influx into the pouch and increases neutrophil phagocytosis of P. gingivalis in the transgenic animals; cutaneous fat deposition was reduced, as was macrophage infiltration. The results suggest that RvE1 rescues impaired neutrophil phagocytosis in obese T2D mice overexpressing ERV1.

Architectural design of the pelvic floor is consistent with muscle functional subspecialization.

INTRODUCTION AND HYPOTHESIS: Skeletal muscle architecture is the strongest predictor of a muscle's functional capacity. The purpose of this study was to define the architectural properties of the deep muscles of the female pelvic floor (PFMs) to elucidate their structure-function relationships. METHODS: PFMs coccygeus (C), iliococcygeus (IC), and pubovisceral (PV) were harvested en bloc from ten fixed human cadavers (mean age 85 years, range 55-102). Fundamental architectural parameters of skeletal muscles [physiological cross-sectional area (PCSA), normalized fiber length, and sarcomere length (L(s))] were determined using validated methods. PCSA predicts muscle-force production, and normalized fiber length is related to muscle excursion. These parameters were compared using repeated measures analysis of variance (ANOVA) with post hoc t tests, as appropriate. Significance was set to α = 0.05. RESULTS: PFMs were thinner than expected based on data reported from imaging studies and in vivo palpation. Significant differences in fiber length were observed across PFMs: C = 5.29 ± 0.32 cm, IC = 7.55 ± 0.46 cm, PV = 10.45 ± 0.67 cm (p < 0.001). Average L(s) of all PFMs was short relative to the optimal L(s) of 2.7 µm of other human skeletal muscles: C = 2.05 ± 0.02 µm, IC = 2.02 ± 0.02 µm, PC/PR = 2.07 ± 0.01 µm (p = <0.001 compared with 2.7 µm; p = 0.15 between PFMs, power = 0.46). Average PCSA was very small compared with other human muscles, with no significant difference between individual PFMs: C = 0.71 ± 0.06 cm(2), IC = 0.63 ± 0.04 cm(2), PV = 0.59 ± 0.05 cm(2) (p = 0.21, power = 0.27). Overall, C had shortest fibers, making it a good stabilizer. PV demonstrated the longest fibers, suggesting that it functions to produce large excursions. CONCLUSIONS: PFM design shows individual muscles demonstrating differential architecture, corresponding to specialized function in the pelvic floor.