Lubricating conditions: effects on friction between orthodontic brackets and archwires with different cross-sections.

OBJECTIVE: This study investigated the effect of the condition of lubrication on the friction between brackets and NiTi archwires of different rounded cross-sections. METHODS: Brackets (Roth, GAC) were affixed to a device connected to a universal testing machine into which segments of archwire were placed (NiTi, Nitinol, GAC) with cross-sections of 0.012-in, 0.016-in and 0.020-in. Once the wire was in the bracket slot, the following lubricants were applied: human saliva (HS: positive control), distilled water (DI), mucin-based (MUC) or carboxymethylcellulose-based (CMC) artificial saliva. In the negative control group, no lubricant was used. The combination between the wire cross-sections and the lubrication condition generated 15 groups with 15 samples each. Data were submitted to two-way analysis of variance and Tukey's test. RESULTS: There was no significant interaction between the wire cross-section and the condition of lubrication (p= 0.901). Irrespective of whether lubricants were used or not, there was a significant increase in friction with an increase in the cross-section of the wire (p< 0.001). For any wire, the group tested in the presence of MUC was not different from that in which HS was applied. On the other hand, when the application of lubricants was suppressed, significantly higher friction values were observed. The CMC group and the DI group demonstrated intermediate behavior. CONCLUSIONS: Friction increased with the increase of the cross-section of the NiTi archwire, but regardless of the archwire, friction with MUC artificial saliva was similar to that of HS and lower than in dry conditions.

Physical Activity Reduces the Prevalence of Periodontal Disease: Systematic Review and Meta-Analysis.

Background: Regular physical activity boosts several physical capacities and reduces many inflammatory markers of several diseases. In this sense, periodontal disease is a multifactorial inflammatory disease of tooth supporting tissues that has been claimed to trigger processes of systemic alterations. The aim of this systematic review and meta-analysis was to assess the effects of physical activity on periodontal disease. Methods: Observational studies published until August 2018 were searched in online databases (PubMed, Scopus, Web of Science, The Cochrane Library, LILACS, OpenGrey, and Google Scholar) after developing a PECO statement that focused on the comparison between adults that followed a routine of exercises or presented a sedentary lifestyle and its effects on periodontal disease. Searching and data extraction were conducted by following PRISMA guidelines. Registration protocol: CRD42016049661. Quality assessment and risk of bias were analyzed by following Fowkes and Fulton protocol. Results: A total of 512 references were retrieved, while only seven were considered eligible. Two meta-analysis involving the prevalence of periodontal disease and unadjusted/adjusted Odds ratio were performed. One of studies did not find association between clinical periodontal parameters and physical activity. Six articles suggested an association between periodontal disease and regular practice of physical activity since a reduction of periodontal prevalence was observed. Moderate level of evidence was demonstrated on GRADE analysis. Conclusion: Physical activity was associated as a potential tool for reduction of periodontal disease prevalence. The frequency of physical activity is directly related to a low occurrence of periodontitis. However, it is important that further investigations evaluate the effects of other exercise variables, such as volume and intensity, on the periodontal disease prevalence.

Periodontitis As A Risk Factor For Stroke: A Systematic Review And Meta-Analysis.

This systematic review and meta-analysis investigate the association between periodontitis and stroke. This review followed the methods established by the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Searches were conducted in five databases and two sources of grey literature. After the selection of the articles, a risk of bias evaluation was performed. Three meta-analyzes were performed: Assessing the overall association between stroke and periodontitis in case-control studies; Ischemic stroke and periodontitis in case-control studies; The association between stroke and periodontitis in cohort studies. Heterogeneity was assessed using the I2 index and the odds ratio was also calculated (p < 0.05). The Grading of Recommendations Assessment, Development and Evaluation (GRADE) was applied to evaluate the level of evidence. 2193 potentially relevant studies were identified, with 10 studies included in qualitative and quantitative analysis. All the articles were considered with low risk of bias and a low level of certainty. The results demonstrated a positive association between both disorders and increased risk for stroke among cohort studies (RR 1.88 [1.55, 2.29], p<0.00001, I2=0%) and for ischemic stroke events in case-control studies (RR 2.72 [2.00, 3.71], p<0.00001, I2= 4%). Periodontitis may represent a risk factor for stroke, especially in ischemic events. However, new studies with a robust design are necessary for a reliable conclusion.

Is there an association between asthma and periodontal disease among adults? Systematic review and meta-analysis.

This systematic review and meta-analysis aimed to investigate a possible association between asthma and periodontal disease in adults. This study was conducted by Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and the searches were performed on the following databases: PubMed, Scopus, Web of Science, Cochrane, LILACS, OpenGrey e Google Scholar. In this systematic review, observational studies with adult humans, which evaluated patients with and without asthma, were selected to verify the association between both diseases. To qualitative analysis, Fowkes and Fulton guidelines was used and for the quantitative analysis, it was used the mean and standard deviation from each group (with and without asthma), using confidence interval (CI) 95% and heterogeneity were tested using I2 index. Furthermore, a summary of the overall strength of evidence was presented using Grading of recommendations, assessment, development, and evaluation (GRADE). 3395 studies were identified, 11 were included on this systematic review to qualitative analysis and 6 of them to quantitative synthesis. Six meta-analyses were performed to the following clinical parameters: plaque index (PI), gingival index (GI), bleeding on probing (BOP), papillary bleeding index (PBI), calculus index (CI), clinical attachment loss (CAL). The meta-analysis results for CI was (p < 0.00001, I2 = 0%) PBI (p < 0.00001, I2 = 0%), CAL (p = 0,03, I2 = 98%) showed higher means for the asthmatic group. For BOP (p = 0.20 I2 = 83%), GI (p = 0.14 I2 = 97%) and PI (p = 0.53 I2 = 95%) non-statistical difference was found. The level of evidence analysis (GRADE) presented a low level of evidence among the clinical parameters. This systematic review and meta-analysis observed that asthmatic individuals present more periodontal disease, especially gingivitis, when compared to healthy individuals, but further studies with similar methods are necessary to evaluate interactions between both diseases.

Lubricating conditions: effects on friction between orthodontic brackets and archwires with different cross-sections

Abstract Objective: This study investigated the effect of the condition of lubrication on the friction between brackets and NiTi archwires of different rounded cross-sections. Methods: Brackets (Roth, GAC) were affixed to a device connected to a universal testing machine into which segments of archwire were placed (NiTi, Nitinol, GAC) with cross-sections of 0.012-in, 0.016-in and 0.020-in. Once the wire was in the bracket slot, the following lubricants were applied: human saliva (HS: positive control), distilled water (DI), mucin-based (MUC) or carboxymethylcellulose-based (CMC) artificial saliva. In the negative control group, no lubricant was used. The combination between the wire cross-sections and the lubrication condition generated 15 groups with 15 samples each. Data were submitted to two-way analysis of variance and Tukey's test. Results: There was no significant interaction between the wire cross-section and the condition of lubrication (p= 0.901). Irrespective of whether lubricants were used or not, there was a significant increase in friction with an increase in the cross-section of the wire (p< 0.001). For any wire, the group tested in the presence of MUC was not different from that in which HS was applied. On the other hand, when the application of lubricants was suppressed, significantly higher friction values were observed. The CMC group and the DI group demonstrated intermediate behavior. Conclusions: Friction increased with the increase of the cross-section of the NiTi archwire, but regardless of the archwire, friction with MUC artificial saliva was similar to that of HS and lower than in dry conditions.

Resumo Objetivo: este estudo investigou o efeito das condições de lubrificação no atrito entre braquetes e fios de NiTi de diferentes secções transversais. Métodos: os braquetes (Roth, GAC) foram fixados a um dispositivo conectado a uma máquina de ensaio universal, que recebeu segmentos de fio de NiTi (Nitinol, GAC) com secções de 0,012"; 0,016" ou 0,020". Após o fio ter sido instalado no slot do braquete, aplicou-se um dos seguintes lubrificantes: saliva humana (SH: controle positivo), água destilada (AD) ou saliva artificial à base de mucina (MUC) ou de carboximetilcelulose (CMC). No grupo controle negativo, nenhum lubrificante foi utilizado. As combinações entre as secções dos fios e as condições de lubrificação geraram 15 grupos, com 15 amostras cada. Os dados foram submetidos à análise de variância a dois critérios e ao teste de Tukey. Resultados: não houve interação significativa entre a secção do fio e a condição de lubrificação (p = 0,901). Independentemente de ter sido utilizado ou não lubrificante, observou-se elevação significativa do atrito com o aumento da secção transversal do fio (p < 0,001). Para qualquer um dos fios, o grupo testado na presença de MUC não diferiu daquele em que se aplicou SH. Por outro lado, quando suprimiu-se os lubrificantes, constatou-se atrito significativamente mais elevado. Os grupos CMC e AD demonstraram comportamento intermediário. Conclusões: o atrito se elevou com o aumento da secção transversal dos fios de NiTi, mas a despeito do fio, o atrito com a saliva à base de MUC foi similar àquele com a SH e menor do que sob condição a seco.