Randomized in situ study on the efficacy of CO2 laser irradiation in increasing enamel erosion resistance.

OBJECTIVES: The aim of this double-blind, randomized in situ study was to evaluate the erosion-preventive effect of a specific set of CO2 laser parameters, associated or not with fluoride. METHODS: Two hundred forty bovine enamel blocks were prepared for individual palatal appliances (n = 6 samples/appliance). The study had four phases of 5 days each, with ten volunteers and the following treatments: CO2 laser irradiation (L), fluoride treatment (F), combined fluoride and laser treatment (FL), and no treatment, control (C). Laser irradiation was performed at 0.3 J/cm2 (5 µs/226 Hz/10.6 µm) and the fluoride gel contained AmF/NaF (12'500 ppm F-/pH = 4.8-6). For erosive demineralization, the appliances were immersed extra-orally in citric acid (0.05 M/20 min/pH = 2.3) twice daily. Analysis of enamel surface loss was done using a 3D-laser profilometer on 3 days. Additionally, fluoride uptake was quantified and scanning electron microscopies were done. Data were analyzed with repeated measures ANOVA and post hoc pairwise comparisons (α = 0.05). RESULTS: At all analyzing days, both laser groups caused the lowest means of enamel loss, which were also statistically significant lower than C (p < 0.05). At day 5, FL means ± SD (33.6 ± 12.6 µm) were even significantly lower than all other groups (C 67.8 ± 15.4 µm; F 57.5 ± 20.3 µm; L 46.8 ± 14.5 µm). Significantly increased enamel fluoride uptake was observed for both fluoride-containing groups (p < 0.05) at day 1. CONCLUSION: Compared to the control, the CO2 laser irradiation with a specific set of laser parameters (0.3 J/cm2/5 µs/226 Hz) either alone or in combination with a fluoride gel (AmF/NaF) could significantly decrease enamel erosive loss up to 5 days in situ. CLINICAL RELEVANCE: Combined CO2 laser-fluoride treatment has a significant anti-erosive effect.

Independent reversals to terrestriality in squirrels (Rodentia: Sciuridae) support ecologically mediated modes of adaptation.

The family Sciuridae is one of the most widespread and ecologically diverse lineages of rodents and represents an ideal model for investigating the evolution of locomotion modes and the historical biogeography of terrestrial mammals. We used a comprehensive database on locomotion modes, an updated phylogeny and novel biogeographic comparative methods to reassess the evolution of locomotion of squirrels and to investigate whether these locomotion modes evolved convergently in different continents. We found that locomotion changes occurred in different independent lineages of the family, including four reversals to terrestriality and one evolution of gliding. We also found evidence for Eurasia as the centre of origin of Sciuridae, challenging the classification of the oldest squirrel fossil records from the early Oligocene in North America. Additionally, Eurasia is also the possible centre of origin for most of squirrel subfamilies and tribes, and where locomotion changes have occurred. Parallel locomotion shifts could be explained by the adaptation towards different ecological niches followed by colonization of new continents.

Cardiovascular responses to different stages of restorative dental treatment unaffected by local anaesthetic type.

BACKGROUND: The aim of this study was to evaluate the cardiovascular effects of maxillary infiltration using 2% lidocaine with 1:100,000 adrenaline, 4% articaine with 1:200,000 adrenaline, and 4% articaine with 1:100,000 adrenaline in different stages during restorative dental procedures. METHODS: Twenty healthy patients randomly received 1.8 mL of the three local anaesthetics. Systolic blood pressure, average blood pressure, diastolic blood pressure, and heart rate were evaluated by the oscillometric and photoplethysmograph methods in seven stages during the appointment. RESULTS: Statistical analysis by ANOVA and Tukey tests of cardiovascular parameters did not show significant differences between the anaesthetic associations. There were significant differences for the parameters among different clinical stages. CONCLUSIONS: The variation of cardiovascular parameters was similar for lidocaine and articaine with both adrenaline concentrations and showed no advantage of one drug over the other. Cardiovascular parameters were influenced by the stages of the dental procedures, which showed the effect of anxiety during restorative dental treatment.

Intoxicação crônica por flúor. Prevalência de fluorose dentária em escolares / Chronic fluorine intoxication. Prevalence of dental fluorosis in schoolchildren

O propósito do presente trabalho foi avaliar a prevalência de fluorose dentária, em escolares (n=956), residentes e nascidos na cidade de São Paulo, onde a água de abastecimento público tem uma concentração de 0,7 ppm de flúor.Para detectar a presença de fluorose dental, foram examinados escolares de ambos sexos, na faixa etária de seis a 16 anos de idade, matriculados na rede pública de ensino, usando o índice Thylstrup e Fejerskov (TF).Os resultados indicam que fluorose dentária (TF³1) ocorreu em 49 por cento dos estudantes, com predominância no sexo feminino.Há elevado predomínio de fluorose leve na maioria dos casos (TF³1) de 62 por cento, TF=2 de 24 por cento e TF=3 de 7 por cento.A análise global dos resultados mostrou que o flúor associado com outros fatores de risco aumentou a prevalência de fluorose, tendo exercido papel significante no declínio da cárie dental na população estudada.

Cardiovascular alterations caused by the administration of 2% mepivacaine HCl with 1:20,000 levonordefrin (Carbocain) in dogs.

We studied possible cardiovascular effects (systolic, diastolic, mean arterial blood pressures, and heart rate) caused by intraoral infiltrative administration of 2% mepivacaine HCl with 1:20,000 levonordefrin in dogs (Canis familiaris), using a Beckman electrophysiograph. Doses used were 0.514 and 1.542 mg/kg body weight corresponding to one and three 1.8-ml cartridges, respectively, in 70-kg average weight adult men. A statistically significant increase was observed in the systolic and the mean arterial blood pressures.