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Biomedical subjects

B P Gomes

Publications and source records attributed to B P Gomes.

17 recordsLinked to original sources
PubMed2001

Apical extrusion of debris and irrigants using two hand and three engine-driven instrumentation techniques.

AIM: To evaluate the weight of debris and irrigant volume extruded apically from extracted teeth in vitro after endodontic instrumentation using the balanced force technique, a hybrid hand instrumentation technique, and three engine-driven techniques utilizing nickel-titanium instruments (ProFile .04, Quantec 2000 and Pow-R). METHODOLOGY: Five groups of 20 extracted human teeth with single canals were instrumented using one or other of five techniques: balanced force, hybrid, Quantec 2000, ProFile .04, or Pow-R. Debris extruded from the apical foramen during instrumentation were collected into preweighed 1.5 mL tubes. Following instrumentation, the volume of extruded irrigant fluid was determined by visual comparison to control centrifuge tubes filled with 0.25 mL increments of distilled water. The weight of dry extruded dentine debris was also established. RESULTS: Overall, the engine-driven techniques extruded less debris than the manual ones. However, there was no statistical difference between the balanced force technique and the engine-driven methods. The volume of irrigant extruded through the apex was directly associated with the weight of extruded debris, except within the ProFile group. The hybrid technique was associated with the greatest extrusion of both debris and irrigant. CONCLUSIONS: Overall, the engine-driven nickel-titanium systems were associated with less apical extrusion.

Dental High-Speed Technique↗
PubMed2001

In vitro antimicrobial activity of several concentrations of sodium hypochlorite and chlorhexidine gluconate in the elimination of Enterococcus faecalis.

AIM: The aim of this study was to assess, in vitro, the effectiveness of several concentrations of NaOCl (0.5%, 1%, 2.5%, 4% and 5.25%) and two forms of chlorhexidine gluconate (gel and liquid) in three concentrations (0.2%, 1% and 2%) in the elimination of E. faecalis. METHODOLOGY: A broth dilution test using 24-well cell culture plates was performed and the time taken for the irrigants to kill bacterial cells was recorded. Isolated 24 h colonies of pure cultures of E. faecalis grown on 10% sheep blood plus Brain Heart Infusion (BHI) agar plates were suspended in sterile 0.85% NaCI solution. The cell suspension was adjusted spectrophotometrically to match the turbidity of a McFarland 0.5 scale. One mL of each tested substance was placed on the bottom of wells of 24-well cell culture plates (Corning, NY), including the control group (sterile saline). Six wells were used for each time period and irrigant concentration. Two mL of the bacterial suspension were ultrasonically mixed for 10 s with the irrigants and placed in contact with them for 10, 30, and 45 s; 1, 3, 5, 10, 20, and 30 min; and 1 and 2 h. After each period of time, 1 mL from each well was transferred to tubes containing 2 mL of freshly prepared BHI + neutralizers in order to prevent a residual action of the irrigants. All tubes were incubated at 37 degrees C for 7 days. The tubes considered to have positive growth were those which presented medium turbidity during the incubation period. Data were analysed statistically by the Kruskal-Wallis test. with the level of significance set at P < 0.05. RESULTS: All irrigants were effective in killing E. faecalis. but at different times. Chlorhexidine in the liquid form at all concentrations tested (0.2%, 1% and 2%) and NaOCI (5.25%) were the most effective irrigants. However, the time required by 0.2% chlorhexidine liquid and 2% chlorhexidine gel to promote negative cultures was only 30 s and 1 min, respectively. CONCLUSIONS: Even though all tested irrigants possessed antibacterial activity, the time required to eliminate E. faecalis depended on the concentration and type of irrigant used.

Anti-Infective Agents, Local↗
PubMed2001

Glycol methacrylate: an alternative method for embedding subcutaneous implants.

The aim of this investigation was to study the use of glycol methacrylate (GMA) as an embedding material for rat subcutaneous tissue, which received implants of tubes with endodontic sealer. After fixation, the specimens were dehydrated in a growing alcohol series up to 95%, immersed in infiltration GMA solution and then in embedding solution. The blocks were cut into 3.0 microm sections and stained with hematoxylin-eosin. The quality of cell definition and staining allowed a quantitative analysis of the cells infiltrated in the end of the tubes. It was also possible to identify each type of inflammatory cell. Moreover, it was possible to distinguish clearly chronic from acute inflammatory cells. The GMA technique is easy to execute and reproducible, and provides a better definition of tissue cells, thus permitting definition of the degree of the inflammatory process. Therefore, it is an excellent alternative for the evaluation of the biocompatibility of endodontic sealers.

Animals↗
PubMed2001

In vitro assessment of the antimicrobial action and the mechanical ability of chlorhexidine gel as an endodontic irrigant.

The objective of this study was to assess the chlorhexidine gluconate gel as an endodontic irrigant. First the ability of chlorhexidine gel to disinfect root canals contaminated in vitro with Enterococcus faecalis was investigated. A scanning electron microscope was also used to evaluate its cleansing ability compared with endodontic irrigants commonly used, such as sodium hypochlorite and chlorhexidine gluconate liquid. The results indicated that the chlorhexidine gel produced a cleaner root canal surface and had an antimicrobial ability comparable with that obtained with the other solutions tested. It was concluded that chlorhexidine gluconate in gel form has potential for use as an endodontic irrigant.

Anti-Infective Agents, Local↗
PubMed2000

In vitro antimicrobial activity of propolis and Arnica montana against oral pathogens.

Arnica and propolis have been used for thousands of years in folk medicine for several purposes. They possess several biological activities such as anti-inflammatory, antifungal, antiviral and tissue regenerative, among others. Although the antibacterial activity of propolis has already been demonstrated, very few studies have been done on bacteria of clinical relevance in dentistry. Also, the antimicrobial activity of Arnica has not been extensively investigated. Therefore the aim here was to evaluate in vitro the antimicrobial activity, inhibition of adherence of mutans streptococci and inhibition of formation of water-insoluble glucan by Arnica and propolis extracts. Arnica montana (10%, w/v) and propolis (10%, w/v) extracts from Minas Gerais State were compared with controls. Fifteen microorganisms were used as follows: Candida albicans--NTCC 3736, F72; Staphylococcus aureus--ATCC 25923; Enterococcus faecalis--ATCC 29212; Streptococcus sobrinus 6715; Strep. sanguis--ATCC 10556; Strep. cricetus--HS-6; Strep. mutans--Ingbritt 1600; Strep. mutans--OMZ 175; Actinomyces naeslundii--ATCC 12104, W 1053; Act. viscosus OMZ 105; Porphyromonas gingivalis; Porph. endodontalis and Prevotella denticola (the last three were clinical isolates). Antimicrobial activity was determined by the agar diffusion method and the zones of growth inhibition were measured. To assess cell adherence to a glass surface, the organisms were grown for 18 h at 37 degrees C in test-tubes at a 30 degree angle. To assay water-insoluble glucan formation, a mixture of crude glucosyltransferase and 0.125 M sucrose was incubated for 18 h at 37 degrees C in test-tubes at a 30 degree angle. Arnica and propolis extracts (20 microl) were added to these tubes to evaluate the % of inhibition of cell adherence and water-insoluble glucan formation. The propolis extract significantly inhibited all the microorganisms tested (p < 0.05), showing the largest inhibitory zone for Actinomyces spp. The Arnica extract did not demonstrate significant antimicrobial activity. Cell adherence and water-insoluble glucan formation were almost completely inhibited by the propolis extract at a final concentration of 400 microg/ml and 500 microg/ml, respectively. The Arnica extract showed slight inhibition of the adherence of the growing cells (19% for Strep. mutans and 15% for Strep. sobrinus) and of water-insoluble glucan formation (29%) at these same concentrations. Thus, the propolis extract showed in vitro antibacterial activity, inhibition of cell adherence and inhibition of water-insoluble glucan formation, while the Arnica extract was only slightly active in those three conditions.

Actinomyces↗
PubMed2000

Radiographic analysis of the development of periapical lesions in normal rats, sialoadenectomized rats and sialoadenectomized-immunosuppressed rats.

The purpose of this study was to investigate and to compare radiographically the development of periapical lesions in the lower left first molar of normal rats, sialoadenectomised rats and sialoadenectomised-immunosuppressed rats. Sixty male Wistar rats, weighing from 170 to 200 g were utilized. The animals were divided equally into three groups: group I--20 normal rats; group II--20 sialoadenectomised rats; and group III--20 sialoadenectomised-immunosuppressed rats. Groups II and III were sialoadenectomized using the modified Cheyne technique. After 2 weeks, group III was submitted to a immunosuppression regimen by daily subcutaneous cyclosporin A injection (10 mg/kg body weight). After 1 week of immunosuppression for this group, the pulps of all the animals (group I, II and III) were exposed to the oral cavity, to produce apical periodontitis. Five animals of each group were killed 7, 14, 21 and 28 days after pulpal exposure. Their mandibles were surgically removed and radiographically analysed. The lesions were measured using 'Global Lab Image' software. The results showed predictable growth of the lesions during the experimental period. No significant difference was observed between the groups. It was concluded that possible changes in the oral flora and in the host immune response due to xerostomia associated or not to the immunosuppression did not alter the development of the periapical lesions in rats.

Animals↗
PubMed1997

Possible lethal enhancement of toxins from putative periodontopathogens by nicotine: implications for periodontal disease.

AIM: To test the hypothesis that lethal synergy in the chick embryo model may occur between nicotine and bacterial products (cell-free extracellular toxins and cell lysates) of five putative periodontopathogens. METHODS: The lethality of cell-free extracellular toxins and cell lysates of five periodontal species was assessed with or without nicotine in the chick embryo assay system. Ten putative periodontopathogens (five species) were studied: Prevotella intermedia (n = 5), Porphyromonas gingivalis (n = 1), Porphyromonas asaccharolytica (n = 1), Fusobacterium nucleatum (n = 2), and Fusobacterium necrophorum (n = 1). RESULTS: Simultaneous testing of cell-free extracellular toxins from isolates W50, PS2, PS3, PS4, and PS5 and nicotine resulted in a percentage kill significantly greater than expected (Fisher's Exact test). Simultaneous testing of cell lysates from isolates W50, PS2, and PS5 and nicotine resulted in a percentage kill significantly greater than expected (Fisher's Exact test). CONCLUSIONS: Lethal synergy in the chick embryo model may occur between nicotine and toxins from putative periodontopathogens (both cell-free extracellular toxins and cell lysates). This may be an important mechanism by which smoking increases the severity of periodontal disease.

Animals↗
PubMed1996

Associations of endodontic symptoms and signs with particular combinations of specific bacteria.

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.

Adolescent↗
PubMed1996

The use of a modelling technique to investigate the root canal morphology of mandibular incisors.

The prime objective of this study was to develop and test a method of modelling the dental root canal system using a vinyl resin, type UCAR-VYHD. It also aimed to verify if the resin models allow a three-dimensional evaluation of those features of the pulpal morphology of human permanent mandibular incisor teeth, which might be associated with periodontal disease. One hundred and eleven freshly extracted teeth were studied. Pre-extraction clinical records and periapical radiographs were used to deduce the presence or absence of periodontal disease. Each extracted tooth was radiographed in two perpendicular planes before being opened by conventional orthograde endodontic technique, and photographed in a scanning electron microscope. The patent pulp space was then obturated with the vinyl resin. Scanning electron photomicrographs of the resin replicas and of the teeth were compared with the earlier radiographic images to correlate the morphological findings. The numbers of root canals and apical foramina were recorded. This study showed that in mandibular incisors with periodontal disease there was a relatively low incidence of lateral canals (7.2%). The modelling technique was found to be reliable, reproducible, and provided sufficient detail to allow three-dimensional analysis of root canal morphology.

Adult↗
PubMed1996

Variations in the susceptibilities of components of the endodontic microflora to biomechanical procedures.

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.

Bacteria↗
PubMed1994

Associations of specific bacteria with some endodontic signs and symptoms.

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.

Bacteria, Anaerobic↗
PubMed1994

Positive and negative associations between bacterial species in dental root canals.

Significant associations have been previously reported between certain pairs of bacterial species isolated from human dental root canals. The aim of this study was to examine microbiologically a more extensive series of cases, with particular reference to obligate anaerobes which accounted for 64% of total isolations. A total of 65 different species was isolated and individual root canals yielded a maximum of eleven bacterial species. Highly significant positive associations (p < 0.001) were found between Peptostreptococcus spp. and Prevotella spp., between Peptostreptococcus spp. and P. melaninogenica, between P. micros and Prevotella spp., P. micros and P. melaninogenica and between Prevotella spp. and Eubacterium spp., all with an ODDS ratio of > 9.0. In contrast, negative and highly significant associations (p < 0.01) were found only between the four species pairs: B. vulgatus/F. necrophorum, P. magnus/Bifidobacterium spp., B. gracilis/F. nucleatum and between B. gracilis/Fusobacterium spp.; all with an ODDS ratio of < 0.5. Some previously published associations were confirmed and some new associations were found, while some negative associations became apparent.

Bacteria, Aerobic↗
PubMedDate not supplied

Clinical significance of dental root canal microflora.

OBJECTIVES: Previous work by this group has shown that a significant association exists between pain and the presence of either Prevotella or Peptostreptococcus spp. in dental root canals. The aim of this study was to examine a more extensive series of canals microbiologically, to determine whether any other particular endodontic symptoms or clinical signs showed specific associations with individual bacterial species. METHODS: Seventy root canals were examined microbiologically and clinical data collected to investigate in detail such associations. RESULTS: Of the canals studied, 37 were associated with pain, 49 with tenderness to percussion, 23 with swelling, six with purulent exudate and 57 presented with wet root canals. Anaerobes were isolated from 70.3% of painful canals and from 29.7% of pain-free canals. Significant associations were found between (a) pain and either Prevotella spp. or peptostreptococci, both with P < 0.01; (b) tenderness to percussion and Prevotella spp. (P < 0.01) or anaerobes (P < 0.05); (c) swelling and Eubacterium spp. (P < 0.01), or with Prevotella spp. or Pstr. micros, both with P < 0.05; (d) purulent exudate and any one of F. necrophorum (P < 0.01), Prev. loescheii, Streptoccoccus constellatus or Bacteroides spp. (each P < 0.05); (e) wet canal and facultative anaerobes (P < 0.01), and any one of the genera of Eubacterium, Peptostreptococcus, Prevotella or Propionibacterium (each P < 0.05). CONCLUSION: It was concluded that several different endodontic clinical signs and symptoms are significantly associated with specific bacterial species.

Adult↗
PubMedDate not supplied

An unusual alteration in the shape of a tooth.

Dental anomalies are an important issue and dentists should be able to manage these conditions. Often, treatment is not necessary; however, some abnormalities may affect the esthetics or function of teeth and can lead to other problems. This case report presents an unusual case of alteration in shape affecting the left lower canine in a 34-year-old woman.

Adult↗