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Biomedical subjects

J D Pécora

Publications and source records attributed to J D Pécora.

At least 19 recordsLinked to original sources
PubMed2006

Anatomoradiographic description of the teeth of pacas bred in captivity (Agouti paca, Linnaeus, 1766).

Two newborn males, two adult males 9 and 72 months old, one newborn female and two adult females of 30 and 54 months old pacas were used. Animals were radiographed on lateral recumbency, teeth were extracted and the vestibulolingual and mesiodistal lengths were achieved at the occlusal surface, besides the longitudinal length. The lower incisors presented greater length in relation to the other ones and sinuous shape; the upper incisors, relatively smaller, are practically straight. There is no canine tooth, and after a great diastema there is one premolar and three molars in each hemiarcade. In adult pacas, the enamel of incisors presents yellowish colour, mainly in the labial surface; in the premolars and molars, the enamel is present as internal sheets disposed nearly in a parallel way and in vestibulolingual direction, through practically all the dental length, which provides several joined teeth aspect.

Animals↗
PubMed2005

Er:YAG laser: antimicrobial effects in the root canals of dogs' teeth with pulp necrosis and chronic periapical lesions.

OBJECTIVE: Our goal in this study was to evaluate the antimicrobial effect of Er:YAG laser applied after biomechanical preparation of the root canals of dog's teeth with apical periodontitis. BACKGROUND DATA: Various in vitro studies have reported effective bacterial reduction in infected root canals using Er:YAG laser. However, there is no in vivo research to support these results. METHODS: Forty root canals of dogs' premolar teeth with pulp necrosis and chronic periapical lesions were used. An initial microbiological sample was taken, and after biomechanical preparation was carried out, a second microbiological sample was taken. The teeth were divided into two groups: Group I-biomechanical preparation was taken of root canals without Er:YAG laser application; Group II-biomechanical preparation was taken of root canals with Er:YAG laser application using 140-mJ input, 63-mJ output/15 Hz. After coronal sealing, the root canals were left empty for 7 days at which time a third microbiological sample was taken. The collected material was removed from the root canal with a #40 K file and placed in transport media. It was serially diluted and seeded on culture dishes selective for anaerobes, aerobes, and total streptococci. Colony-forming units per milliliter (CFU/mL) were counted. RESULTS: Groups I and II showed an increase of CFU/mL for all microorganisms 7 days after treatment, being statistically significant for anaerobes in Group I and for anaerobes and total streptococci in Group II. When comparing CFU/mL of Groups I and II, there was a statistically significant increase after 7 d for total streptococci in Group II. CONCLUSION: Er:YAG laser applied after biomechanical preparation did not reduce microorganisms in the root canal system.

Animals↗
PubMed2002

Clinical aspects of pulpal-periodontal lesions.

It is well known that the main purpose of dentistry is to keep teeth in the oral cavity so that they may fulfill their various roles. This case report demonstrates a method to treat a situation involving a pulpal-periodontal lesion, by using a simple and efficient combined therapy. The clinician can thereby determine the cause of the lesion (pulpal and/or periodontal) and subsequently establish the correct treatment, thus improving the prognosis of the case.

Adult↗
PubMed2001

Control of microorganisms in vitro by calcium hydroxide pastes.

AIM: The aim of this study was to determine the influence of vehicles on the antimicrobial efficiency of calcium hydroxide. METHODOLOGY: A total of 588 size 50 sterile absorbent paper points, were immersed in various microbial suspensions for 3 min. The points were then placed on Petri dishes and covered with intracanal dressings containing calcium hydroxide: Ca(OH)2 + saline; Ca(OH)2 + camphorated paramonochlorophenol; Ca(OH)2 + 1% chlorhexidine solution: Ca(OH)2 + 3% sodium lauryl sulphate; Ca(OH)2 + Otosporin. After 1 min, 48 and 72 h and 7 days, 147 absorbent paper cones were removed from contact with the intracanal dressings and individually transported and immersed in 5 mL of Letheen Broth, followed by incubation at 37 degrees C for 48 h. Microbial growth was evaluated by turbidity of the culture medium. A 0.1-mL inoculum obtained from the Letheen Broth was transferred to 5 mL of BHI, and incubated at 37 degrees C for 48 h. Bacterial growth was again evaluated by turbidity of the culture medium. Positive BHI tubes were selected and inocula were spread on the surface of BHI agar and incubated at 37 degrees C for 48 h. Gram staining of the BHI growth and from colonies growing on BHI agar was carried out. RESULTS: An antimicrobial effect occurred after 48 h on the cultures of S. mutans, E. faecalis, S. aureus, P aeruginosa, B. subtilis, C. albicans and a mixed culture, irrespective of the intracanal dressing. CONCLUSIONS: Under the conditions of this study, the various vehicles associated with calcium hydroxide pastes did not influence the time required for microbial inactivation.

Anti-Infective Agents, Local↗
PubMed2001

Microleakage of a resin sealant after acid-etching, Er:YAG laser irradiation and air-abrasion of pits and fissures.

OBJECTIVE: The aim of this in vitro study was to assess microleakage underneath a filled pit-and-fissure sealant bonded to occlusal surfaces treated by four enamel etching techniques. SUMMARY BACKGROUND DATA: There has been no report of a study assessing microleakage of a pit-and-fissure sealant, comparing acid-etching, Er:YAG laser and air-abrasion for treating enamel surface. METHODS: Forty extracted human third molars were selected and randomly assigned into four groups of ten teeth: group I, the occlusal surfaces were acid-etched; group II, a very short pulsed Er:YAG laser was used to treat the surfaces; group III, aluminum oxide air-abrasion was associated with acid-etching; group IV, Er:YAG laser was associated with acid-conditioning. The surfaces were sealed and the teeth were stored for 7 days in distilled water. Then, specimens were thermocycled, immersed in a 0.2% rhodamine solution, sectioned, and analyzed for leakage using an optical microscope connected to a video camera. The images were digitized and analyzed by software that allowed microleakage assessment in millimeters. RESULTS: Statistical analysis showed that occlusal surfaces treated exclusively by the Er:YAG laser (group II) provided the poorest marginal sealing and that acid-etching (group I) was statistically similar to aluminum oxide air-abrasion + acid etching (group III) and to Er:YAG laser + acid-etching (group IV). CONCLUSIONS: The results suggest that complementing either air-abrasion or Er:YAG laser irradiation with a subsequent acid-conditioning did not lessen microleakage at the enamel-sealant interface when compared with an acid-etched group. It was also observed that treating the enamel surface exclusively by Er:YAG laser resulted in the highest degree of leakage.

Acid Etching, Dental↗
PubMed2001

Evaluation of the effect of EDTAC, CDTA, and EGTA on radicular dentin microhardness.

The effect of EDTAC (ethylenediamine tetra-acetic acid plus Cetavion, an ammonium surfactant), CDTA (cyclohexane-1,2-diaminetetra-acetic acid), and EGTA (ethylene glycol-bis-(beta-amino-ethyl ether) N,N,N',N'-tetra-acetic acid) on the microhardness of radicular dentin of the cervical third of human teeth was studied. Five newly extracted maxillary incisors were sectioned transversely at the cementoenamel junction, and the crowns were discarded. The roots were embedded in blocks of high-speed polymerized acrylic resin and cut transversely into 1-mm sections. The second slice of the cervical third of the root of each tooth was sectioned and divided into four parts. Each part was placed on an acrylic disc that was used as a base for microhardness measurement. Fifty microliters of 15% EDTAC, 1% CDTA, or 1% EGTA were applied to the dentin surface. Deionized and distilled water was used as control. Dentin microhardness was then measured with a Vicker's microhardness apparatus with a load of 50 g for 15 s. Statistical analysis showed that the three chelating solutions significantly reduced dentin microhardness when compared with water; however, there was no statistically significant difference among the three solutions.

Analysis of Variance↗
PubMed2001

Evaluation of Er:YAG laser and EDTAC on dentin adhesion of six endodontic sealers.

The effect of Er:YAG laser application and EDTAC on the adhesion of epoxy resin-based endodontic sealers to human dentin was evaluated in vitro. A total of 99 extracted human maxillary molars with their crowns worn flat were used. The teeth were divided into 3 groups: group 1, the dentin surface received no treatment; group 2, EDTAC was applied to the dentin surface for 5 min; group 3, the dentin surface received Er:YAG laser application (2.25 W potency; 11 mm focal distance; 4 Hz frequency; 200 mJ energy; 62 J total energy; 313 mean impulse). Three teeth from each group were analyzed by scanning electron microscopy for changes in dentin surface. The epoxy resin root canal sealers used were: AH Plus, Topseal, Sealer 26, AH 26, and Sealer Plus. The zinc oxide eugenol-based sealer Fillcanal was used as control. Adhesion was measured with a Universal testing machine. The results showed a statistically significant difference at the level of 1% among the dentin treatments. The dentin treated with Er:YAG laser showed greater adhesion with the sealers than dentin treated with EDTAC which was greater than dentin that received no treatment. The Tukey test showed the formation of 5 groups in decreasing order of adhesion: AH Plus, Topseal and Sealer 26, AH 26, Sealer Plus, and Fillcanal (Grossman cement).

Adhesives↗
PubMed2001

Modeling capacity of ENDOflash files in simulated root canals.

With the development of rotary nickel-titanium files and their applications in Endodontics, the concepts of root canal preparation have changed. The objective of this research is to evaluate the transportation of simulated root canals caused by stainless steel ENDOflash rotary files compared to nickel-titanium ProFile files (.04, .06 and Orifice Shapers). Twenty-four simulated root canals with a 30 degrees curvature were randomly divided into 2 groups and prepared with ENDOflash or ProFile files according to manufacturers' instructions. Comparison between the simulated root canals before and after instrumentation showed significant differences (p < 0.001) between the groups, with greater transportation observed with ENDOflash files. One case of deformation was observed with a ProFile instrument (#20/.04) and there were no fractures.

Dental Alloys↗
PubMed2001

Dental anomaly: dens evaginatus (talon cusp).

Dens evaginatus is a developmental anomaly characterized by the occurrence of an extra cusp shaped as a tubercle projecting from the palatal or buccal surfaces (talon cusp). In the anterior dentition, dens evaginatus is more commonly found in the maxilla and on the palatal surface of the tooth. The authors present a case of dens evaginatus in a maxillary central incisor, in which the evagination was removed and routine endodontic treatment was performed.

Adolescent↗
PubMed2001

Solvent action of sodium hypochlorite on bovine pulp and physico-chemical properties of resulting liquid.

The solvent effect of 4 concentrations of sodium hypochlorite (0.5, 1.0, 2.5, and 5.0%) on bovine pulp tissue and the level of residual chlorine, pH and surface tension before and after dissolution were studied in vitro. A fragment of bovine pulp was submersed in sodium hypochlorite that circulated in an apparatus with a peristaltic pump and Luer Lok syringe. The higher the concentration of sodium hypochlorite the faster the dissolution of the pulp tissue. All concentrations of sodium hypochlorite reduced the pH and the surface tension and the higher concentrations of the solution had the least consumption of chlorine during tissue dissolution. Thus this study indicated that residual chlorine was directly proportional to concentration in the process of pulp tissue dissolution and that there was residual chlorine at all concentrations used.

Animals↗
PubMed2000

Treatment of middle-apical level root fracture in necrotic teeth.

The purpose of this paper is to present two case reports of dental trauma with middle-apical level root fractures and pulp necrosis. The treatment consisted of programmed applications of calcium hydroxide until a calcified barrier was formed at the fracture level. The technique presented here proved efficient in treating horizontal fractures at the middle and apical thirds of the root.

Adult↗
PubMed2000

In vitro study of the effect of aged eugenol on the flow, setting time and adhesion of Grossman root canal sealer.

In the present study, the effect of aged eugenol (up to 180 days) on the flow, setting time and adhesion of Grossman root canal sealer was evaluated, following the American Dental Association specification number 57 for root canal sealers. An Instron Universal testing machine 4444 was used for testing adhesion. There were statistically significant differences between groups, with a higher flow, lower setting time and adhesion for aged eugenol. It can be concluded that time affects eugenol, with consequent effects on Grossman sealer.

Adhesiveness↗
PubMed2000

Antimicrobial and chemical study of MTA, Portland cement, calcium hydroxide paste, Sealapex and Dycal.

The objective of this study was to investigate the antimicrobial action of mineral trioxide aggregate (MTA), Portland cement, calcium hydroxide paste (CHP), Sealapex and Dycal. The chemical elements of MTA and two Portland cements were also analyzed. Four standard bacterial strains: Staphylococcus aureus (ATCC 6538), Enterococcus faecalis (ATCC 29212), Pseudomonas aeruginosa (ATCC 27853), Bacillus subtilis (ATCC 6633), one wild fungus, Candida albicans (ICB/USP-562), and one mixture of these were used. Thirty Petri plates with 20 ml of BHI agar were inoculated with 0.1 ml of the experimental suspensions. Three cavities, each one measuring 4 mm in depth and 4 mm in diameter, were made in each agar plate using a copper coil and then completely filled with the product to be tested. The plates were pre-incubated for 1 h at environmental temperature followed by incubation at 37 degrees C for 48 h. The diameters of the zones of microbial inhibition were then measured. Samples from diffusion and inhibition halos were extracted from each plate and immersed in 7 ml BHI broth and incubated at 37 degrees C for 48 h. Analyses of chemical elements present in MTA and in two samples of Portland cement were performed with a fluorescence spectrometer Rx. The results showed that the antimicrobial activity of CHP was superior to those of MTA, Portland cement, Sealapex and Dycal, for all microorganisms tested, presenting inhibition zones of 6-9.5 mm and diffusion zones of 10-18 mm. MTA, Portland cement, and Sealapex presented only diffusion zones and among these, Sealapex produced the largest zone. Dycal did not show inhibition or diffusion zones. Portland cements contain the same chemical elements as MTA except that MTA also contains bismuth.

Aluminum Compounds↗
PubMed1999

Effect of different grades of gum rosins and hydrogenated resins on the solubility, disintegration, and dimensional alterations of Grossman cement.

In the present study, we investigated the effect of the addition of different grades of gum rosins and hydrogenated resins to Grossman cement on dimensional stability, solubility and disintegration. pH and conductivity, which may affect these properties, were also determined. The experiments were performed according to Specification 57 of the American Dental Association for root canal cements using Grossman cements containing three gum rosins (grades X, WW, and WG) and two hydrogenated resins (Staybelite and Staybelite ester 10). The results showed that the solubility, disintegration, and dimensional stability of Grossman cement containing Staybelite and Staybelite ester 10 were inferior to the values considered acceptable by the American Dental Association Specification 57.

Analysis of Variance↗
PubMed1999

Effect of vehicle on antimicrobial properties of calcium hydroxide pastes.

The current discussion about the importance of intracanal dressings and the effect of vehicles on calcium hydroxide pastes is justified by controversy concerning the achievement of complete disinfection after preparation of infected root canals and the real antimicrobial effect of these vehicles. The aim of this study is to investigate the role of vehicles in the antimicrobial effect of calcium hydroxide pastes. Well-conducted research about the characteristics of calcium hydroxide, such as antimicrobial potential, physico-chemical aspects and histocompatibility, gives credibility to the choice of this medication in several clinical situations. Different vehicles have been added to calcium hydroxide in an attempt to enhance its properties. Scientific reasoning indicates the use of hydrosoluble vehicles (distilled water, saline) associated with calcium hydroxide because of their chemical characteristics of dissociation, diffusibility and filling capability which are decisive for the biological behavior, i.e., antimicrobial qualities and induction of tissue repair.

Anti-Infective Agents, Local↗
PubMed1998

The external and internal anatomy of human mandibular canine teeth with two roots.

This study investigated the internal anatomy of 65 human mandibular canines with two well-defined roots. The teeth were decalcified and injected with gelatin coloured with india ink. Diaphanization was carried out using clear resin to allow permanent preservation. It was found that all mandibular canines with two roots had two root canals. Lateral canals were found in 68.9% of teeth and 19.7% had lateral canals at the bifurcation. The results of the external measurements (cusp tip to root apex) showed that the average buccal root length was 23.0 mm and the average lingual root length was 22.7 mm. The maximum and minimum buccal lengths were 26.7 mm and 17.9 mm respectively and the maximum and minimum lingual lengths were 27.2 mm and 17.1 mm respectively. The buccal root was the larger of the two in 47.7% of teeth and 43.1% had roots of equal size. The lingual root was larger than the buccal root in 9.2% of cases. Clinicians should be aware of the anatomical variation that exists for mandibular canines.

Cuspid↗
PubMed1998

External and internal anatomy of third molars.

The external and internal anatomy of 269 third molars (155 maxillary and 114 mandibular) were studied. The teeth were measured, classified according to their root number and shape and the internal anatomy was observed by the use of diaphanization. A great anatomical variability was found, with the presence of up to 5 roots in maxillary third molars and 3 roots in mandibular third molars. The number of root canals followed the same pattern.

Dental Pulp Cavity↗