Metabolomic Signatures of In Vitro Biofilm Maturation of Streptococcus mutans.

The Streptococcus mutans is commonly find in oral environment in both symbiont and dysbiotic conditions, where for the last one it causes the break in homeostatic balance and, in association with other microorganisms' community, results in dental caries process. Additionally, it is important to determine the low molecular weight metabolites profile from Streptococcus mutans to distinguish the endogenous and exogenous compounds from patient subjected to salivary metabolomic studies. Thus, the objective of the present study was to characterize the in vitro metabolomic profile of the maturation of a single-species Streptococcus mutans biofilm using metabolomic approach by 1H-nuclear magnetic resonance (NMR) spectroscopy. A distinct metabolomic profile was observed after 2 days of biofilm maturation, independently of the presence of enamel substrate. Sucrose, lactate, and fructose were the main metabolites responsible for the distinction. The sucrose was consumed by S. mutans in higher levels in the initial experimental periods than at 6 days of biofilm growth. Lactate and fructose were the main compounds secreted, regardless of the type of growth, but it was also observed production of propionate, iso-butyrate, and pyruvate. Pyruvate metabolism and glycolysis/gluconeogenesis were the main pathways related to biofilm growth. The results contribute to the determination of compounds that are resulted from oral microbial activity and help to guide further metabolomics studies.

Evaluation of mandibular implant-supported fixed prosthesis retained by 3 dental implants, 1 straight and 2 angled: A retrospective clinical study.

STATEMENT OF PROBLEM: The minimum number of implants to support fixed complete dentures is still unclear. PURPOSE: The purpose of this retrospective clinical study was to evaluate the survival rate of fixed complete dentures supported by 3 immediately loaded implants opposing maxillary complete dentures. MATERIAL AND METHODS: A retrospective study of edentulous patients rehabilitated with complete dentures opposing mandibular metal-resin implant-supported fixed complete dentures supported by 3 immediately loaded implants was conducted in a 48-hour protocol. Fifty-one machined and 99 rough-surface implants were evaluated from 2.2 up to 8 years. Implant loss, peri-implant outcomes, and mechanical complications were assessed by considering the influence of age, sex, health status, smoking, excessive alcohol consumption, educational level, and socioeconomic status. The presence of comorbidities in relation to the implant surface or the cantilever lengths was also evaluated. RESULTS: Four machined and 6 rough-surface implants failed, a 6.7% failure rate. The cantilever length varied from 3.3 to 22.9 mm. Mechanical complications were abutment screw loosening (3.0%), prosthetic screw loosening (17%), screw fracture (1%), superstructure detachment and fractures (16%), metal framework fracture (2%), maxillary denture fractures (6%), and mandibular prosthesis loss (4%). Peri-implant mucositis was found in 27% of participants. The cumulative implant and mandibular prosthesis survival rates were 93.3% and 96%, respectively. None of the variables evaluated, including demographic data and health status, were found to influence clinical failures and/or mechanical complications. CONCLUSIONS: Mandibular fixed complete dentures supported by 3 implants can be considered a successful treatment with reduced costs compared with those of other fixed options for application in public health.

Salivary metabolome of children and adolescents under peritoneal dialysis.

OBJECTIVE: To study the influence of peritoneal dialysis (PD) on the salivary metabolite profile of children and adolescents with renal failure. MATERIALS AND METHODS: Healthy children/adolescents (n = 31; mean age: 12.18 ± 3.76) and children/adolescents subjected to PD (n = 12; mean age: 10.10 ± 4.25) were recruited. Oral health status assessed by the dmft/DMFT and Volpe-Manhold calculus indices. The 1H spectra were acquired in a 600-MHz Bruker nuclear magnetic resonance spectrometer and were subjected to multivariate analysis using partial least squares discriminant analysis (PLS-DA), orthogonal PLS-DA (O-PLS-DA), and univariate analysis through chi-square and t tests (SPSS 20.0, IL, USA), with a significance level of p < 0.05. RESULTS: A similar caries pattern (p = 0.57; chi-square test) was observed between the healthy (dmft = 0.72 ± 1.28 and DMFT 0.93 ± 2.30) and PD groups (dmft = 2.14 ± 3.67, DMFT 0.33 ± 0.71) and dental calculus (p > 0.05, t test). PLS-DA and O-PLS-DA were able to distinguish both groups (ACC = 0.85, R2 = 0.80, Q2 = 0.15). Salivary metabolites decrease in creatine, propionate, and sugar levels in the PD group and an increase in creatinine, butyrate, and lactate levels when compared with the healthy group. CONCLUSIONS: Children and adolescents subjected to PD have a different salivary metabolic profile from that of their healthy subjects. CLINICAL RELEVANCE: Complications of peritoneal dialysis procedures could be monitored by proper knowledge of saliva characteristics as predictors of peritonitis-related outcome. The use of metabolomics in pediatric nephrology may be an innovative methodology for the early diagnosis and monitoring of kidney diseases.

Does the natural maxillary dentition influence the survival rate of mandibular metal-resin implant-supported fixed complete dentures? A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Consensus is lacking regarding the influence of the maxillary dentition on the survival rate of a mandibular metal-resin implant-supported fixed complete denture (MRISFCD) with distal cantilevers. PURPOSE: The purpose of this systematic review was to identify whether an opposing natural dentition influences the survival rate of mandibular MRISFCDs. MATERIAL AND METHODS: A literature search was performed up to February 2018 from MEDLINE/PubMed, Scopus, Web of Science, Cochrane Library, BBO/LILACS databases and also in the non-peer-reviewed literature through Open Grey. Clinical studies regarding natural (ND), removable prostheses (RP), and complete fixed maxillary implant dentitions (ID) with at least a year of follow-up were included. The quality of the included studies was analyzed, and the risk of bias was reported. A meta-analysis comparing the survival rate of ND with RP and ND with ID was performed with a confidence interval (CI) of 95%, and heterogeneity was tested by an I2 index. Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach was used to determine the certainty of the evidence. RESULTS: From a total of 112 ND, 69 ID, and 204 RP in the maxillary dentition, the overall prevalence of failures was 5.4% (6/112; 95% CI [2.3 to 10.76]) for ND, 13.99% (20/69; 95% CI [0.77 to 39.41]) for ID, and 4.9% (10/204; 95% CI [0.69 to 12.18]) for RP. No statistical differences were detected in the success rates between ND and RP (risk difference = 0.00 [-0.06, 0.06]; P=.93; I2=27%) or between ND and ID (risk difference=0.00 [-0.06, 0.07]; P=.97; I2=0%), both with moderate evidence. CONCLUSION: With a moderate certainty of evidence, it is suggested that natural maxillary dentitions do not affect the survival rate of mandibular MRISFCDs differently from other prosthetic designs.