Comparative effectiveness of hand scaling by undergraduate dental students following a two-week pre-clinical training course

BACKGROUND The Bologna reform resulted in a drastic restructuring of pre-clinical training courses at the University of Zurich. The aim of this study was to assess student pre-clinical scaling/root planning skills after just 8.5 hours of manual training. MATERIAL AND METHODS Three consecutive classes of dental students (n = 41; n = 34; n = 48) were tasked with removing lacquer concrement from the maxillary left canine on a typodont using Gracey and universal (Deppeler M23A) curettes. At baseline (prior to instruction), a timed five-minute session of scaling/root planning was undertaken. The second scaling/root planning session was held immediately following training. Eight experienced dental hygienists and eight lay people served as positive and negative controls, using the same instruments and time limit, respectively. Instrumented teeth were collected, scanned and planimetrically analysed for the percentage of tooth surface cleaned. Statistical analyses were performed to assess the dental students' improvement after the training (Wilcoxon signed-rank test) and to compare it to that of laypeople and dental hygienists (Kruskal-Wallis rank sum test followed by Conover's post hoc test). RESULTS At baseline, the dental students' mean scaling scores of the cleaned surfaces were not significantly different than those of laypeople (29.8%, 31.0%, 42% vs 27.9%). However, after 8.5 hours of manual training, the students' ability to clean the maxillary tooth improved significantly and they achieved mean removal values of 61.7%, 79.5% and 76% compared to the 67.4% (P < .001) of the experienced dental hygienists (Tables Tables  and ). There were no statistically significant differences between the scores achieved by students after training and those achieved by experienced dental hygienists. CONCLUSION A shortened pre-clinical training time was sufficient for students to acquire the basic scaling/root planning skills needed in preparation for clinical training. Further research is needed to identify ways to help students consistently reach highest skill levels

The effect of clinical education on optimizing self-care by dental students in Switzerland

Students, who may begin their dental education with sub-optimal oral self-care practices, are taught they should motivate patients to clean interdentally and reduce/stop smoking. To better understand their internalization of these concepts, students were surveyed at two distinct time points. Student cohorts from four Swiss universities were asked to complete an interdental cleaning/smoking habit questionnaire at the beginning of their pre-clinical education (n = 110) and again a year later, when beginning treatment of patients (n = 115). A local cohort (n = 28) was observed for comparison. All subjects participated voluntarily and anonymously. Interdental cleaning ≥ 3 times per week was performed by 48% first-year and 43% secondyear students in Basel, 60% and 76% in Bern, 60% and 70% in Geneva, 41% and 49% in Zurich, and 29% in the local cohort. Logistic regression using gender, class year and school as explanatory variables showed gender (p < 0.001) and school (p = 0.018) influenced cleaning frequency, with the odds being 3.16 [95% CI: 1.76, 5.67] times higher for females to perform interdental cleaning ≥ 3 times per week. Smoking was reported both years in numbers too low to analyze. Approximately 29% of the local cohort and 52% of the first-year students displayed an interdental cleaning frequency congruent with oral health recommendations. Adequate cleaning frequency increased for second-year students to 58%, which was not significant. Further study is needed to determine why more dental students do not themselves clean interdentally

The effect of green tea as an adjunct to scaling and root planing in non-surgical periodontitis therapy: a systematic review

OBJECTIVE To provide a systematic overview on the efficacy of green tea catechin as an adjunct to scaling and root planing (SRP) in terms of probing pocket depth (PPD). MATERIALS AND METHODS A systematic literature search was performed using electronic databases in PubMed, Scopus, Medline, Cochrane, CINAHL, and Web of Science on randomized clinical trials up to January 2017. The research question was posed in accordance with PRISMA guidelines. RESULTS The search provided 234 studies. After analyzing the full texts, five studies were included, with four studies qualifying for meta-analysis. Mean PPD reduction was significantly higher (α = 0.05) when green tea catechin was used as an adjunct to SRP (test group) than with SRP alone (control group). The difference in the reduction was 0.74 mm [0.35-1.13; 95% CI]. CONCLUSION The local application of green tea catechin as an adjunct to SRP may result in a beneficial reduction in PPD. Due to the highly heterogeneous data and some risk of bias, however, this data still needs to be interpreted with caution. CLINICAL RELEVANCE The finding suggests that green tea catechin may be a topical adjunct to SRP without negative side effects

Dissecting Colistin Resistance Mechanisms in Extensively Drug-Resistant Acinetobacter baumannii Clinical Isolates

Nosocomial infections with; Acinetobacter baumannii; are a global problem in intensive care units with high mortality rates. Increasing resistance to first- and second-line antibiotics has forced the use of colistin as last-resort treatment, and increasing development of colistin resistance in; A. baumannii; has been reported. We evaluated the transcriptional regulator PmrA as potential drug target to restore colistin efficacy in; A. baumannii; Deletion of; pmrA; restored colistin susceptibility in 10 of the 12 extensively drug-resistant; A. baumannii; clinical isolates studied, indicating the importance of PmrA in the drug resistance phenotype. However, two strains remained highly resistant, indicating that PmrA-mediated overexpression of the phosphoethanolamine (PetN) transferase PmrC is not the exclusive colistin resistance mechanism in; A. baumannii; A detailed genetic characterization revealed a new colistin resistance mechanism mediated by genetic integration of the insertion element IS; AbaI; upstream of the PmrC homolog EptA (93% identity), leading to its overexpression. We found that; eptA; was ubiquitously present in clinical strains belonging to the international clone 2, and IS; AbaI; integration upstream of; eptA; was required to mediate the colistin-resistant phenotype. In addition, we found a duplicated IS; AbaI; -; eptA; cassette in one isolate, indicating that this colistin resistance determinant may be embedded in a mobile genetic element. Our data disprove PmrA as a drug target for adjuvant therapy but highlight the importance of PetN transferase-mediated colistin resistance in clinical strains. We suggest that direct targeting of the homologous PetN transferases PmrC/EptA may have the potential to overcome colistin resistance in; A. baumannii; IMPORTANCE; The discovery of antibiotics revolutionized modern medicine and enabled us to cure previously deadly bacterial infections. However, a progressive increase in antibiotic resistance rates is a major and global threat for our health care system. Colistin represents one of our last-resort antibiotics that is still active against most Gram-negative bacterial pathogens, but increasing resistance is reported worldwide, in particular due to the plasmid-encoded protein MCR-1 present in pathogens such as; Escherichia coli; and; Klebsiella pneumoniae; Here, we showed that colistin resistance in; A. baumannii; , a top-priority pathogen causing deadly nosocomial infections, is mediated through different avenues that result in increased activity of homologous phosphoethanolamine (PetN) transferases. Considering that MCR-1 is also a PetN transferase, our findings indicate that PetN transferases might be the Achilles heel of superbugs and that direct targeting of them may have the potential to preserve the activity of polymyxin antibiotics

Use of network analysis to capture key traits affecting tomato organoleptic quality

The long-term objective of tomato breeders is to identify metabolites that contribute to defining the target flavour and to design strategies to enhance it. This paper reports the results of network analysis, based on metabolic phenotypic and sensory data, to highlight important relationships among such traits. This tool allowed a reduction in data set complexity, building a network consisting of 35 nodes and 74 links corresponding to the 74 significant (positive or negative) correlations among the variables studied. A number of links among traits contributing to fruit organoleptic quality and to the perception of sensory attributes were identified. Modular partitioning of the characteristics involved in fruit organoleptic perception captured the essential fruit parameters that regulate interactions among different class traits. The main feature of the network was the presence of three nodes interconnected among themselves (dry matter, pH, and °Brix) and with other traits, and nodes with widely different linkage degrees. Identification of strong associations between some metabolic and sensory traits, such as citric acid with tomato smell, glycine with tomato smell, and granulosity with dry matter, suggests a basis for more targeted investigations in the future

Examining molecular interactions and dynamics in centrosome and centriole assembly

Centrioles are cellular organelles that give rise to the centrosome, a structure composed of a pair of centrioles surrounded by pericentriolar material. Centrosomes perform a variety of different cellular functions: they are the main microtubule organising centre in animal cells and are important signalling hubs. The centrosome is composed of hundreds of different proteins, but only a handful are essential. In Drosophila, Sak/Plk4, Ana2, Sas-6, Sas-4 and Asl are required for centriole assembly and Spd-2 and Cnn are indispensable for PCM assembly. Many questions remain regarding how these proteins behave, interact and are regulated, as genetic analysis of these processes is often complicated by the absence of centrioles when these proteins are mutated. In this thesis, I apply recent technological advancements and a biological model system to the study of essential centriole proteins. Using newly developed fluorescent proteins, I am able to localise Sak over the cell cycle in live embryos. Developing and applying a correlative microscopy approach, I was able to localise the protein termini of Ana2 and Sas-6 with nanometre precision to the centriole cartwheel. With the further characterisation and utilization of an in vivo centriole model system, I shed light on the direct contribution of Sak, Asl and Sas-4 on the Ana2/Sas-6 interaction, definitively identify the role of Asl in Spd-2 and Cnn recruitment, and develop a protein-protein interaction assay. The latter led me to identify novel Cdk1/Cyclin B phosphorylation sites on Ana2, providing a possible insight into the cell cycle and centriole duplication cycle link.</p

Examining molecular interactions and dynamics in centrosome and centriole assembly

Centrioles are cellular organelles that give rise to the centrosome, a structure composed of a pair of centrioles surrounded by pericentriolar material. Centrosomes perform a variety of different cellular functions: they are the main microtubule organising centre in animal cells and are important signalling hubs. The centrosome is composed of hundreds of different proteins, but only a handful are essential. In Drosophila, Sak/Plk4, Ana2, Sas-6, Sas-4 and Asl are required for centriole assembly and Spd-2 and Cnn are indispensable for PCM assembly. Many questions remain regarding how these proteins behave, interact and are regulated, as genetic analysis of these processes is often complicated by the absence of centrioles when these proteins are mutated. In this thesis, I apply recent technological advancements and a biological model system to the study of essential centriole proteins. Using newly developed fluorescent proteins, I am able to localise Sak over the cell cycle in live embryos. Developing and applying a correlative microscopy approach, I was able to localise the protein termini of Ana2 and Sas-6 with nanometre precision to the centriole cartwheel. With the further characterisation and utilization of an in vivo centriole model system, I shed light on the direct contribution of Sak, Asl and Sas-4 on the Ana2/Sas-6 interaction, definitively identify the role of Asl in Spd-2 and Cnn recruitment, and develop a protein-protein interaction assay. The latter led me to identify novel Cdk1/Cyclin B phosphorylation sites on Ana2, providing a possible insight into the cell cycle and centriole duplication cycle link.</p

Influence of ultrasonic tip distance and orientation on biofilm removal

OBJECTIVE The aim of this study is to assess the effects of ultrasonic tip distance and orientation on the removal of a multispecies biofilm under standardized conditions in vitro. METHODS Six-species biofilms were grown on hydroxyapatite discs for 64 h and treated with a magnetostrictive ultrasonic tip (Cavitron) placed either on contact or at 0.25- and 0.5-mm distance. The treatment was performed for 15 s with either the tip at right angle or sideways. Biofilm removal was evaluated by assessing the viable bacteria in each supernatant and compared to respective controls. In the latter, biofilms were mechanically removed and evaluated in supernatants to assess adhering and floating bacteria. Colony-forming units (CFU) were determined by cultivation on solid media. Any remaining biofilm on the treated discs was also visualized after staining with green-fluorescent SYTO® 9 stain using a confocal laser scanning microscope (CLSM). Mann-Whitney U tests and Bonferroni correction were used to analyze the results between the groups. RESULTS Sideways application of the ultrasonic tip at distances of 0.25 and 0.5 mm removed as many bacteria as present on the control discs compared to the tip on contact (p < 0.05). All other application modes, especially the ultrasonic tip applied perpendicularly on contact, showed no statistical significance in removing biofilm. CONCLUSION Overall, data indicated that bacterial detachment depended on tip orientation and distance, especially when the tip was applied sideways similar to the clinical setting. CLINICAL RELEVANCE Biofilm removal by means of ultrasonic debridement remains a crucial aspect in the treatment of periodontal disease. To ensure sufficient biofilm removal, the tip does not necessarily require contact to the surface, but an application parallel to the surface on the side is recommended

Treatment Success and User-Friendliness of An Electric Toothbrush App: A Pilot Study

Electronic and mobile health (eHealth/mHealth) are rapidly growing areas in medicine and digital technologies are gaining importance. In dentistry, digitalization is also an emerging topic, whereby more and more applications are being offered. As an example, using real-time feedback, digital application software (an app) was designed to help users brush their teeth more accurately. However, there is no data on the effectiveness and haptic of such apps. Therefore, a single-blinded, randomized controlled clinical trial was designed: twenty volunteers received an electric toothbrush with an associated app to assess whether the app-assisted toothbrushing is better than without. After a short period of familiarization with the electric toothbrush, plaque index (O'Leary et al. 1972) was recorded and subjects were assigned to the test (with app; n = 10) or the control group (no app; n = 10). At the end of the 2-week pilot study period, plaque was again assessed and participants in the test group completed a questionnaire about the app's user-friendliness. Statistical analysis revealed no significant differences between the test and control groups. The plaque index improved on average by 8.5% points in the test and 4.7% points in the control group. Fifty percent of the test group participants were of the opinion that they had achieved better cleaning results and would recommend the app to others, although the app contributed only marginally to increased plaque removal. However, such apps may nevertheless be helpful as motivational tools, especially when tracking and monitoring cleaning data. Therefore, more development and research on this topic is indicated