Membrane-plate transition in leaves as an influence on dietary selectivity and tooth form.

Primates need accurate sensory signals about food quality to forage efficiently. Current evidence suggests that they target leaf foods based on color at long-range, reinforcing this with post-ingestive sensations relating to leaf toughness evoked during chewing. Selection against tough leaves effectively selects against high fiber content, which in turn gives a greater opportunity of acquiring protein. Here we consider a novel intermediate mechanical factor that could aid a folivore: leaves may transform mechanically from membranes (sheets that cannot maintain their shape under gravitational loads and thus 'flop') early on in development into plates (that can maintain their shape) as they mature. This transformation can be detected visually. Mechanical tests on two species of leaf eaten by southern muriqui monkeys (Brachyteles arachnoides) in Southern Atlantic Forest, Brazil, support a membrane-to-plate shift in turgid leaves during their development. A measure of this mechanical transition, termed lambda (λ), was found to correlate with both leaf color and toughness, thus supporting a potential role in leaf selection. Muriquis appear to select membranous leaves, but they also eat leaves that are plate-like. We attribute this to the degree of cresting of their molar teeth. A dietary choice restricted to membranous leaves might typify the type of 'fallback' leaf that even frugivorous primates will target because membranes of low toughness are relatively easily chewed. This may be relevant to the diets of hominins because these lack the bladed postcanine teeth seen in mammals with a specialized folivorous diet. We suggest that mammals with such dental adaptations can consume tougher leaf 'plates' than others.

The influence of abutment disconnections on peri-implant marginal bone: A systematic review.

PURPOSE: To assess the failure rate of dental implants and prosthetic restoration, complications and marginal bone loss (MBL) of implants restored with an immediate definitive abutment at the time of the implant placement, and implants that were evaluated according to a standard prosthetic protocol (SPP), which includes multiple abutment changes. MATERIALS AND METHODS: This systematic review followed the guidelines of the PRISMA statement (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). An electronic search with no date or language restriction was run in January 2018 in the PubMed/MEDLINE, Cochrane Central Register of Controlled Trials, Web of Science, and complemented with a manual search. Randomised clinical trials with at least a 12-month follow-up evaluating the use of a definitive abutment and a SPP were included. The Cochrane Collaboration Risk of Bias tool was used to evaluate the included studies. The outcome measures were: implant and prosthetic failure; aesthetics; complications; and peri-implant MBL. The results were pooled using a random-effect model with mean differences (MDs) for continuous outcomes and risk ratio for dichotomous outcomes with a 95% confidence interval (CI). RESULTS: The search identified a total of 714 studies. After the screening process five studies were included in the analysis. The five studies included had a limited sample size, a short follow-up period, and four studies were considered at high risk of bias. The meta-analysis revealed that five studies using an immediate definitive abutment over a 12- to 18-month follow-up resulted in lower MBL, with a MD of -0.32 mm (95% CI -0.45 to -0.19: P < 0.0000). At the end of a 3-year follow-up two studies showed a MD of -0.33 mm (95% CI -0.63 to -0.03: P = 0.03, which also favours the definitive abutment group. Regarding implant failure rate, complications, and probing depth, no significant difference was found between the groups. CONCLUSIONS: Within the limitations of this meta-analysis, reducing the number of abutment changes contributes to statistically significant lower MBL. However, the clinical significance of this reduction in bone loss should be interpreted with caution. A high implant success rate was reported by all studies for both control and test groups.

O emprego dos anestésicos locais em Odontologia: Revisão de Literatura / The usage of local anesthetics in Dentistry: Review of Literature

Anestésicos locais são usados diariamente nos consultórios odontológicos, existindo vários tipos de soluções contendo ou não vasoconstritores. É consenso na literatura de que não se pode indicar o mesmo anestésico para todos os pacientes, dadas suas características individuais, sua condição sistêmica normal ou a presença de doenças como diabetes ou hipertensão, além da possibilidade da gravidez. O uso inadequado do anestésico pode levar a sérios riscos para a saúde do paciente ou até mesmo ao óbito. Após a análise e discussão dos trabalhos relatados na literatura, a indicação do anestésico local parece ser um pouco negligenciada quanto ao conhecimento científico. Com as inúmeras variáveis sistêmicas do paciente, tipo e dosagem dos anestésicos a maioria dos profissionais e estudantes de Odontologia revelaram dificuldade nesta escolha.

The local anesthetics are used daily in the dental office there are several types of solutions with or without vasoconstrictor. Furthermore, there is consensus in the literature that one cannot indicate the same anesthetic for all patients, given their individual characteristics, their systemic condition normal or being a carrier of diseases such as diabetes or hypertension and the possibility of pregnancy. And the inappropriate use of anesthetic can lead to serious health risks of the patient or even to death. After analysis and discussion of the works reported in the literature they indicate that the local anesthesia seems to be somewhat neglected as scientific knowledge and with numerous systemic variables of the patient, type and dosage of anesthetics most professionals and dental students showed a lot of difficulty in this choice.