Success rate of first attempt 4% articaine para-apical anesthesia for the extraction of mandibular wisdom teeth.

Dental extraction is one of the acts that cannot be undertaken or carried out without total analgesia. Unfortunately, the success of anesthesia is not always systematic. Failures are noted during the extraction of mandibular wisdom teeth and pain management therefore remains a challenge for their extraction. The anesthesia technique and nature of the adapted anesthetic solution are controversial. However, the most commonly used technique is the Lower Alveolar Nerve Block (IANB). This technique has disadvantages (trismus, risk of intra-arterial injection and hematoma) and a failure rate of up to 88%. In some survey, 90% of 93 practitioners had difficulty obtaining proper anesthesia. Other clinical studies have also shown overall failure rates of 37%-47%, and 15%-35% on healthy lower molars. Recent studies have evaluated the success rate of articaine at between 54% and 94%, while others have shown that for mandibular teeth, articaine is more effective in para-apical anesthesia than lidocaine. Sixty subjects were selected for the study. The aim was to evaluate the overall success rate of first intention 4% articaine para-apical anesthesia during extraction of third mandibular molars. The overall success rate of para-apical anesthesia was 87%.

Using (137)Cs and (210)Pbex and other sediment source fingerprints to document suspended sediment sources in small forested catchments in south-central Chile.

A study of the impact of forest harvesting operations on sediment mobilization from forested catchments has been undertaken in south-central Chile. The study focused on two sets of small paired catchments (treatment and control), with similar soil type, but contrasting mean annual rainfall, located about 400 km apart at Nacimiento (1200 mm yr(-1)) and Los Ulmos (2500 mm yr(-1)). The objective was to study the changes in the relative contribution of the primary sources of fine sediment caused by forestry operations. Attention focused on the pre-harvest and post-harvest periods and the post-replanting period was included for the Nacimiento treatment catchment. The sediment source fingerprinting technique was used to document the contributions of the potential sources. Emphasis was placed on discriminating between the forest slopes, forest roads and channel erosion as potential sources of fine sediment and on assessing the relative contributions of these three sources to the sediment yield from the catchments. The fallout radionuclides (FRNs) (137)Cs and excess lead-210, the environmental radionuclides (226)Ra and (40)K and soil organic matter (SOM) were tested as possible fingerprints for discriminating between potential sediment sources. The Kruskal-Wallis test and discriminant function analysis were used to guide the selection of the optimum fingerprint set for each catchment and observation period. Either one or both of the FRNs were selected for inclusion in the optimum fingerprint for all datasets. The relative contribution of each sediment source to the target sediment load was estimated using the selected fingerprint properties, and a mixing model coupled with a Monte Carlo simulation technique that takes account of uncertainty in characterizing sediment source properties. The goodness of fit of the mixing model was tested by comparing the measured and simulated fingerprint properties for the target sediment samples. In the Nacimiento treatment catchment the relative contribution from the forest slopes and forest roads increased from 16 to 25% and from 37 to 45%, respectively, after clearcutting. Similar changes in source contributions associated with clearcutting were documented for the Los Ulmos treatment catchment, where the relative contribution of the forest slopes increased from 10.5 to 30% and that of the roads from 10 to 20%. The results indicate that the changes in sediment source are closely related to the disturbance of the catchment by clearcutting, but are also influenced by the amount of rainfall that occurred after clearcutting. They also emphasise the need to implement better management practices during forest harvesting, to reduce the increase in sediment mobilization from catchment slopes and roads, which can result in loss of valuable soil and associated nutrients from the forest floor and cause degradation of the water quality of adjacent streams.

[Acquirement of the Spanish vocabulary among rural and urban students of the 9th region]. / Adquisición del vocabulario castellano entre escolares rurales y urbanos de la novena región.

In order to test the assumption that rural children from the Araucanía region at southern Chile start school with significant handicaps in the acquirement of the spanish vocabulary when compared with their urban peers, the Peabody Picture Vocabulary Test (PPVT, spanish version) was used to compare a first group including all those children attending third grade at a public school from a low socio economic level neighborhood of the city of Temuco, Chile (n = 44, age average 9.01 years, s = 0.51) against a second group including all those children attending the same grade at three public schools from the rural areas surrounding the same city (n = 37, age average 9.07 years, s = 0.52). Previously, 19 children aged 3 to 5 years were tested both with the PPVT and with the chilean instrument for the measurement of development at the age group (TEPSI). Both scores show a positive correlation (r = 0.64, p = 0.05). Average scores for the PPVT among rural children were lower than among urban children (64.07, s = 11.36 against 103.05, s = 10.99, p = less than 0.01). In a second stage, 39 children attending 7th grade at the urban school (age average 13.61 years, s = 0.64) and 27 children of the same grade from the rural schools (age average 13.69 years, s = 0.69) were tested with the same instrument.(ABSTRACT TRUNCATED AT 250 WORDS)