SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: Dentistry journal

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The human body supports the growth of a wide array of microbial communities in various niches such as the oral cavity, gastro-intestinal and urogenital tracts, and on the surface of the skin. These host associated microbial communities include yet-un-cultivable bacteria and are influenced by various factors. Together, these communities of bacteria are referred to as the human microbiome. Human oral microbiome consists of both symbionts and pathobionts. Deviation from symbiosis among the bacterial community leads to “dysbiosis”, a state of community disturbance. Dysbiosis occurs due to many confounding factors that predispose a shift in the composition and relative abundance of microbial communities. Dysbiotic communities have been a major cause for many microbiome related systemic infections. Such dysbiosis is directed by certain important pathogens called the “keystone pathogens”, which can modulate community microbiome variations. One such persistent infection is oral infection, mainly periodontitis, where a wide array of causal organisms have been implied to systemic infections such as cardio vascular disease, diabetes mellitus, rheumatoid arthritis, and Alzheimer’s disease. The keystone pathogens co-occur with many yet-cultivable bacteria and their interactions lead to dysbiosis. This has been the focus of recent research. While immune evasion is one of the major modes that leads to dysbiosis, new processes and new virulence factors of bacteria have been shown to be involved in this important process that determines a disease or health state. This review focuses on such dysbiotic communities, their interactions, and their virulence factors that predispose the host to other systemic implications.

Concepts: Immune system, Inflammation, Archaea, Disease, Infectious disease, Bacteria, Microbiology, Infection

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Successful management of oral mucositis, dysgeusia and oral dryness was made with fivesessions of photobiomodulation. The severity of oral mucositis was measured according to the World Health Organization scale for the assessment of oral mucositis. Dysgeusia testing was performed according to the International Standards Organization (ISO). For the assessment of oral dryness or hyposalivation, quantity of the total resting and stimulated saliva (Q-sal, mL/min) was measured.Photobiomodulation parameters, applications, and treatment protocol used were suggested by an international multidisciplinary panel of clinicians and researchers with expertise in the area of supportive care in cancer and/or PBM clinical application and dosimetry. This case report confirms the effectiveness of photobiomodulation therapy in the management of oral mucositis, dysgeusia, and oral dryness.

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Sports dentistry assumes a clinical relevance, not only in the prevention of orofacial trauma by the use of mouthguards, but also with the development of intraoral devices that aim to provide greater occlusal stability, as well as a greater balance in the level of certain structures of the cranio-cervical-mandibular complex. In this way, the dentistry can have an intervention action on sports performance.

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Molar incisor hypomineralisation (MIH) is a common enamel condition, presenting with incisor opacities, which may be of psychosocial concern to children. This clinical study sought to determine whether minimally invasive treatment, aiming to improve incisor aesthetics, would also improve children’s oral health-related quality of life (OHRQoL). 111 MIH patients, aged 7⁻16 years, referred to a UK Dental Hospital, were invited to complete the Child Oral Health Impact Profile (C-OHIP-SF19) prior to any intervention (T₀) and again at one-month following the intervention (T₁) for MIH. Treatment regimens included one or more of the following: Microabrasion; resin infiltration; tooth whitening; resin composite restoration. Data were obtained for 93 children with a mean age of 11 years. Mean total C-OHIP-SF19 score at T₀ was 47.00 (SD = 9.29; range = 0⁻76) and this increased significantly at T₁ to 58.24 (SD = 9.42; range = 0⁻76; p < 0.001, paired t-test), indicating a marked improvement in self-reported OHRQoL. There were no statistically significant differences according to gender. This is the first study to show that simple, minimally invasive dental treatment, to reduce the visibility of enamel opacities, in MIH, can have a positive impact on children's wellbeing.

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Wind instrumentalists like clarinetists, may present a muscular hyperactivity on certain groups of the cranio-cervico-mandibular complex, due to their musical activity. Therefore, the use of infrared thermography can be used to assess and characterize the orofacial structures involved in clarinet performance.

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The aim of this study was to investigate the association of stress and anxiety with the expectation, perception and memory of dental pain among schoolchildren. A follow-up study involving 46 children aged 9 to 12 years was conducted in a public school in the city of Petropolis (RJ), Brazil. Demographic characteristics, stress (children’s stress scale), and state and trait anxiety (state⁻trait anxiety inventory) were recorded before a dental procedure to restore the occlusal surface of a permanent first molar under local anaesthetic. Dental pain was assessed using the faces pain scale before (dental pain expectation), immediately after (dental pain perception) and six weeks after (memory of dental pain) the dental procedure. Dental pain expectation scores were significantly higher than dental pain perception, independent of the levels of stress, state anxiety and trait anxiety. Children with high scores of stress (OR 1.05 95%CI 1.02⁻1.09), state anxiety (OR 1.15 95%CI 1.05⁻1.27) and trait anxiety (OR 1.18 95%CI 1.07⁻1.30) were more likely to report greater scores of dental pain expectation. Children anticipated more dental pain than what was actually perceived after the dental restoration. Children with greater levels of stress and anxiety have a distorted evaluation of expected dental pain before the dental procedure.

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Aging invokes physiological changes, such as immunosenescence and inflammation, that could increase host susceptibility to oral microbiome shifts that enable periodontitis progression in later life. At present, there is a dearth of studies specifically evaluating the oral microbiome and periodontitis in older adults. We used high-throughput untargeted sequencing methods and functional metagenomic analyses to assess and compare the subgingival biofilm of postmenopausal women (mean age 71 years) according to periodontitis status. Subgingival plaque samples were obtained from 15 postmenopausal women with no periodontitis, and from 15 women with severe periodontitis, determined by probing measures. The 16S rRNA gene (V1⁻V3 region) was sequenced on the 454 FLX platform. The PICRUSt technique was used to provide information on what the potential functional characteristics of microbiota might be in healthy, compared with diseased, periodontium. The subgingival microbiome associated with periodontitis showed clear differences to that associated with health. Of the 464 species identified, 22.8% had elevated abundance in disease, while only 6.3% had elevated abundance in health. Among the 12 most prevalent organisms in periodontitis, one-half have previously been recognized as periodontal pathogens by other investigators. The subgingival microbiome in periodontitis contained genes that could code for specific activities, including microbial mobility, synthesis of endotoxin, and proteolytic degradation. The healthy microbiome included genes that could code for sustaining microbial life, including encoding for transporters, glycolysis, gluconeogenesis, the Krebs cycle, and protein kinases. In the present study on postmenopausal women, aged 60 and older, the subgingival microbiome differed in composition and potential function between those with and without periodontitis. Studies of functional gene expression, such as transcriptomics, are needed to definitively identify the molecules carrying out functions associated with pathogenic subgingival complexes. This, in turn, could lead to identification of targets for enhanced management of periodontitis and, possibly, other diseases, in later life.

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On account of its proven clinical efficacy, the combination of systemically administered amoxicillin and metronidazole is frequently adjuncted to non-operative periodontal therapy and well documented. Potential drawbacks of this regimen, e.g., side effects and problems with the compliance, led to an ongoing search for alternatives. Azithromycin, an antibiotic extensively used in general medicine, has recently found its niche in periodontal therapy as well. This systematic review aimed to analyze the in vitro antimicrobial efficacy of amoxicillin plus metronidazole versus azithromycin. For this purpose, a systematic literature search was performed, and studies published up to 29 March 2018 referenced in Medline, Embase, Cochrane, and Biosis were independently screened by two authors. An additional hand search was performed and studies focusing on the evaluation of in vitro antimicrobial efficacy of amoxicillin + metronidazole or azithromycin on bacteria from the subgingival biofilm were included. English and German language research reports were considered. From 71 identified articles, only three articles were eligible for inclusion. These studies showed heterogeneity in terms of analytical methods and strains explored. However, all studies used multispecies biofilm models for analysis of the antimicrobial activity. Unanimously, studies reported on more pronounced antimicrobial effects when applying the combination of amoxicillin + metronidazole, compared to azithromycin. Based on the few studies available, the combination of amoxicillin + metronidazole seemed to display higher antimicrobial efficacy in vitro than azithromycin.

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The transcription factor Twist1 is known to be closely associated with the formation of bone by mesenchymal stem cells and osteoblasts; however, the role of Twist1 in cementogenesis has not yet been determined. This study was undertaken to elucidate the roles of Twist1 in cementoblast differentiation by means of the gain- or loss-of-function method. We used alkaline phosphatase (ALP) and alizarin red S staining and quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) to determine whether the forced transient expression or knock-down of Twist1 in a mouse cementoblast cell line, OCCM-30, could affect cementogenic differentiation. Silencing Twist1 with small interference RNA (siRNA) enhanced the formation of mineralized tissue. The expression of several cementogenesis markers, such as bone sialoprotein (BSP), osteopontin (OPN), dentin matrix protein1 (DMP1), and dentin sialophosphoprotein (DSPP) mRNA, were upregulated. Transient Twist1 overexpression in OCCM-30 consistently suppressed mineralization capacity and downregulated the differentiation markers. These results suggest that the Twist1 transcription factor may play a role in regulating cementoblast differentiation.

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Advances in adhesive dentistry have led to increased use of indirect restorations. In some situations, indirect composite techniques are more advantageous than direct composite filling techniques, such as establishing proper occlusal and interproximal anatomy, reducing polymerization shrinkage stress, and promoting the degree of conversion. This article presents a case about restoring the lower right first molar with extensive loss of tooth structure by the composite onlay to achieve a proper anatomic form and rehabilitate chewing function. This one-year clinical case encourages clinicians to manage large decay of posterior tooth conservatively. The given functional and esthetic outcomes demonstrate the promising applicability of the indirect composite technique.