The role of the endodontic microflora in pulpal disease and in endodontic treatment failures is well established. Thus the need for effective microbial control is one of the important justifications for biomechanical procedures. However the efficacy of this stage of treatment is dependent upon the vulnerability of the involved species, which may not be uniform. The aim of this study was to investigate variations in the susceptibilities of members of the root canal microflora to routine biomechanical procedures. Forty-two root canals were investigated microbiologically. Samples were collected before and after instrumentation and the bacterial findings were compared. In 15 cases of 'primary' root canal therapy, despite changes in the population size, no significant change in the species composition of the microflora was observed. However in 27 cases 'secondary' treatment, a decrease in the number of isolations of Peptostreptococcus spp. was found (P = 0.008). When all 42 cases were considered together, significant decreases were found between first and second samples for anaerobes (P = 0.0117) and for Grampositive species (P = 0.008), especially Peptostreptococcus spp. (P = 0.02). It was therefore concluded that certain species are more resistant to the biomechanical procedures than others.
Although a wide range of bacterial species has been isolated from infected dental root canals it remains necessary to determine whether any particular group of such bacteria is associated with specific endodontic symptoms and clinical signs. In this study 30 root canals were examined microbiologically; of these, 14 were associated with pain, 20 with tenderness to percussion, 23 presented with wet root canals, seven with swelling, five with purulent exudate and four with a sinus. Clinical and microbiological correlation was observed particularly with regard to pain where anaerobes were isolated from 93% of painful canals and only from 53% of painfree canals. The former yielded means of 2.5 anaerobic species and 1.6 facultative species per canal, compared with 1.5 and 2.4 in painfree canals. Prevotella spp. were isolated from 64.2% of painful canals and 12.5% of painless canals (P < 0.01) similarly, peptostreptococci were isolated from 71.4% of painful and 31.3% of painless canals (P < 0.05). It was concluded that a significant association exists between pain and the presence of Prevotella and Peptostreptococcus spp. in dental root canals.
Significant associations have been reported between (a) specific bacterial species isolated from root canals and (b) between individual bacterial species and endodontic symptoms and signs. The prime objective of this study was to determine whether particular combinations of specific bacteria are associated with individual endodontic symptoms and signs. Seventy root canals were investigated microbiologically taking care to maintain the viability of obligate anaerobes, which accounted for 64% of the total species isolated, including Peptostreptococcus micros, Prevotella melaninogenica, Prevotella oralis, Eubacterium aerofaciens, Eubacterium lentum, Fusobacterium nucleatum, Prevotella buccae and Prevotella intermedia. Significant associations were found between individual clinical features and the following pairs of species: (a) pain (37 cases) and Peptostreptococcus spp./Prevotella spp., Peptostreptococcus spp./Prevotella melaninogenica, Pstr. micros/Prev. melaninogenica (all P < 0.01); (b) swelling (23 cases) and Pstr. micros/Prevotella spp. (P < 0.01); (c) 'Wet' canal (57 cases) and Prevotella spp./Eubacterium spp. (P < 0.01), Peptostreptococcus spp./Eubacterium spp. (P < 0.05). Thus data from this investigation suggests that statistically significant associations exist between individual endodontic symptoms and signs and particular combinations of specific bacteria.
Previous research on the effect of lecture handouts on student learning indicates that students who are given skeletal handouts usually perform better in course examinations than students who take all their own notes. The present study investigates whether the amount of detail in the handout is a critical factor in this. A randomized groups experiment was conducted in the context of a course on dental surgery. Four lecture handout conditions (headings and full text; headings and key points; headings only; no supplementary materials) were compared on tests 2 days and 2 weeks after the lecture. The significant differences between conditions were: 'headings only' better than 'headings and key points' on the first test; 'headings only' better than 'no supplementary materials' on the second test; and 'headings and full text' better than 'no supplementary materials' on the second test. These results indicate that the amount of detail is a critical factor in handout effectiveness.Most students attending lecture courses in higher education take notes and use them for private study. Previous research has investigated whether reviewing such notes improves student performance in course examinations. Hardly surprisingly, there is widespread evidence of suchan effect. In a recent review, Kiewra (1985a) lists 22 studies on this issue, of which 17 found a facilitating effect and five no significant result. Four further studies not included in Kiewra's review also report a facilitating effect (Crawford, 1925a, b;Hartley and Marshall, 1974;Hartley, 1976).However, any benefit gained from reviewing notes will depend on their quality as a record of the lecture. To investigate this, a number of researchers have 'marked' students' lecture notes for accuracy and completeness, and then correlated these scores with the students' examination performance after they have used the notes for private study (Howe, 1970a;Fisher and Harris, 1974;Hartley and Marshall, 1974;Aiken, Thomas and Shennum, 1975;Maddox and Hoole, 1975;Locke, 1977). All these studies report significant positive correlations between the quality of the students' notes and their examination performance, but a poor quality of note-taking overall. Research on the quality of lecture notes is reviewed by Kiewra (1985b), who cites five studies in addition to the above, each of which also revealed a serious degree of incompleteness and inaccuracy. It is likely, therefore, that students would learn more from lectures if they obtained a better record of the lecture content. One way of attempting to ensure this is to issue
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.