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Biomedical subjects

Maria Fidela de Lima Navarro

Publications and source records attributed to Maria Fidela de Lima Navarro.

12 recordsLinked to original sources
PubMed2006

Effect of hygroscopic expansion on the push-out resistance of glass ionomer-based cements used for the luting of glass fiber posts.

This study examined the contribution of hygroscopic expansion of glass-ionomer (GIC) and resin modified glass-ionomer (RMGIC) luting cements to the push-out resistance of fiber posts. Glass fiber posts were luted to post spaces using different cements. Experimental specimens were stored in water, while control specimens were desiccated and stored in mineral oil to eliminate water from intraradicular dentinal tubules and/or the external environment that could have contributed to hygroscopic expansion of the cements. Thin slice push-out tests revealed no difference in retention strengths of resin composite cements that were stored in water or oil. Conversely, GIC and RMGIC cements exhibited increased retention strengths after water sorption. As unfavorable cavity geometry is taxing to dentin bond integrity in root canals, a strategy that relies on increasing the frictional resistance to post dislodgement via delayed hygroscopic expansion of glass-ionomer based materials may be a more pragmatic approach to fiber post retention.

Acrylic Resins↗
PubMed2005

Effect of different finishing and polishing techniques on the surface roughness of microfilled, hybrid and packable composite resins.

This study examined the average surface roughness (Ra, microm) of 2 microfilled (Durafill and Perfection), 1 hybrid (Filtek Z250) and 2 packable composite resins (Surefil and Fill Magic), before (baseline) and after eight different finishing and polishing treatments. The surface roughness was assessed using a profilometer. Ten specimens of each composite resin were randomly subjected to one of the following finishing/polishing techniques: A -- carbide burs; B -- fine/extrafine diamond burs; C -- Sof-Lex aluminum oxide discs; D -- Super-Snap aluminum oxide discs; E -- rubber polishing points + fine/extrafine polishing pastes; F -- diamond burs + rubber polishing points + fine/extrafine polishing pastes; G -- diamond burs + Sof-Lex system; H -- diamond burs + Super-Snap system. Data were analyzed using two-way ANOVA and Tukey's HSD test. Significant differences (p<0.05) were detected among both the resins and the finishing/polishing techniques. For all resins, the use of diamond burs resulted in the greatest surface roughness (Ra: 0.69 to 1.44 microm). The lowest Ra means were obtained for the specimens treated with Sof-Lex discs (Ra: 0.11 to 0.25 microm). The Ra values of Durafill were lower than those of Perfection and Filtek Z250, and these in turn had lower Ra than the packable composite resins. Overall, the smoothest surfaces were obtained with the use the complete sequence of Sof-Lex discs. In areas that could not be reached by the aluminum oxide discs, the carbide burs and the association between rubber points and polishing pastes produced satisfactory surface smoothness for the packable and hybrid composite resins, respectively.

Aluminum Oxide↗
PubMed2005

Microhardness of resin-based materials polymerized with LED and halogen curing units.

The purpose of this study was to evaluate the microhardness of resin-based materials polymerized with a LED (light-emitting diode) light-curing unit (LCU) and a halogen LCU. Twenty cylindrical specimens (3.0 mm in diameter and 2.0 mm high) were prepared for each tested material (Z100, Definite and Dyract). Specimens were light-cured with two LCUs (Ultraled and Curing Light 2500) for either 40 or 60 s on their top surfaces. Hardness was measured on top and bottom surfaces of each specimen. Statistical analysis was done by ANOVA and Tukey's test (p<0.05). There was no significant difference in hardness between LED LCU and halogen LCU for Z100 and Dyract on top surface. Conversely, lower hardness was recorded when Definite was light-cured with the LED LCU than with the halogen lamp. On bottom surface, hardness was significantly lower for all materials light-cured with LED LCU. Z100 was harder than Dyract and Definite regardless of the light curing unit. There was no significant difference in hardness between the exposure times on top surface. Higher hardness was obtained when the materials were light-cured for 60 s on bottom surface. The tested LED was not able to produce the same microhardness of resin-based materials as the halogen LCU.

Compomers↗
PubMed2004

In vivo effect of a resin-modified glass ionomer cement on enamel demineralization around orthodontic brackets.

Because the risk of dental caries increases with the use of orthodontic appliances and its control cannot depend only on the patient's self-care, this study evaluated the effect of a glass ionomer cement on reducing enamel demineralization around orthodontic brackets. Fourteen orthodontic patients were randomly divided into 2 groups of 7; they received 23 brackets fitted to their premolars, bonded with either Concise (3M Dental Products, St Paul, Minn), a composite resin (control group), or Fuji Ortho LC (GC America, Chicago, Ill), a resin-modified glass ionomer cement (experimental group). The volunteers lived in a city that has fluoridated water, but they did not use fluoridated dentifrices during the study. After 30 days, the teeth were extracted and longitudinally sectioned; in the enamel around the brackets, demineralization was assessed by cross-sectional microhardness. The determinations were made at the bracket edge cementing limits, and at occlusal and cervical points 100 and 200 microm away from them. In all of these positions, indentations were made at depths from 10 to 90 microm from enamel surface. Analysis of variance showed statistically significant effects for position, material, depth, and their interactions (P<.05). The Tukey test showed that the glass ionomer cement was statistically more efficient than the control, reducing enamel demineralization in all analyses (P<.05). The use of glass ionomer cement for bonding can be encouraged because it decreases the development of caries around orthodontic brackets.

Acrylic Resins↗
PubMed2004

Occlusal caries detection: a comparison of DIAGNOdent and two conventional diagnostic methods.

OBJECTIVES: The aims of this study were: 1) to compare the DIAGNOdent readings for the detection of caries on three different macroscopically sound and intact occlusal surfaces for the baseline measurement; and 2) to compare this laser device with visual and radiographic inspection. METHODOLOGY: Forty-five extracted premolars and molar human teeth were cleaned with a pumice slurry. Then 74 sites were defined and radiographs were taken from each one. Three examiners performed the examinations and took the DIAGNOdent measurements. Sensitivity and specificity were calculated for each diagnostic system, as well as intra- and inter-examiner reproducibility using Kappa tests. The cut-off point for visual and radiographic inspection was 1-2, and for the DIAGNOdent the manufacturer's instructions were followed. RESULTS: No statistical difference was found for the three predefined sound sites used for baseline measurements with DIAGNOdent. The visual inspection showed high sensitivity; radiographic inspection and DIAGNOdent measurements showed low sensitivity and high specificity. The highest intra- and inter-reproducibility was found with the DIAGNOdent. CONCLUSION: The thickness of the enamel did not have any effect on the readings with DIAGNOdent. It was concluded that in a low prevalence sample, the visual inspection provided the highest proportion of true disease identified correctly, and DIAGNOdent provided the highest proportion of non-disease identified correctly.

Bicuspid↗
PubMed2003

Effect of caries preventive measures directed to expectant mothers on caries experience in their children.

The aim of this prospective study was to determine the effectiveness of caries preventive measures started during pregnancy on the caries experience of first-time mothers and their infants. Eighty-one pregnant women with low social background were selected on the basis of the presence of active carious lesions and were randomly divided into control (38) and experimental (43) groups. The initial dental status (DMFS and white spot lesions) was established through clinical examination. The prophylactic measures were repeated during pregnancy and 6 and 12 months after delivery. Both groups received primary care intervention. They were instructed in relation to the etiologic factors of dental caries and received oral hygiene kits. Oral hygiene instructions were reinforced through interactive brushing. The experimental group also received antimicrobial treatment (topical application of NaF and iodine solution immediately after prophylaxis and 3 and 5 days later) and restorative care using glass ionomer cement. By the time the children were 2 years of age, 33.3% of the infants in the control group and 14.7% in the experimental group had caries activity. A significant difference in caries prevalence was observed between children with and without visible dental plaque. The mean number of tooth surfaces with carious lesions (including areas of demineralization) was higher among the children in the control group compared to the experimental group (6.3 x 3.2), however, with no statistical significance. Maternal caries increase was a significant factor influencing the caries experience of the children. These data support the evidence of an association between caries prevalence in young children and clinical (dental plaque) and maternal factors.

Adult↗
PubMed2003

Clinical evaluation of the ART technique using high density and resin-modified glass lonomer cements.

PURPOSE: The aim of this study was to evaluate the performance of two different glass ionomer cements using the Atraumatic Restorative Treatment (ART) technique in permanent teeth. MATERIALS AND METHODS: A total of 473 ART restorations were placed in 208 schoolchildren (7-12 years of age) by two previously trained operators, using high density and resin-modified glass ionomer cements. All the restorations were photographed at baseline and the patients were asked about postoperative sensitivity. After a period of 8 months, 193 patients were present after recall and 428 restorations were evaluated and photographed. Two independent examiners carried out the evaluation. RESULTS: The results showed a success rate of 86.2% for occlusal restorations with Fuji IX and 88.4% for those restored with Fuji Plus. A total of 86.7% of the approximal restorations with Fuji Plus were also judged to be successful after 8 months. No association was found between the materials and the clinical performance of the ART restorations in class I cavities. CONCLUSION: The type of restorative material did not influence the success or failure rates in class I cavities within this period. Fuji IX showed promising performance for occlusal ART restorations and Fuji Plus is also a promising material for occlusal and approximal ART restorations.

Chi-Square Distribution↗
PubMed2002

Mechanical properties and bond strength of glass-ionomer cements.

PURPOSE: The objective of this study was to evaluate the mechanical properties and bond strength of glass-ionomer cements (GICs) and resin-modified GICs (RM-GICs) that are indicated as restorative materials for the Atraumatic Restorative Treatment (ART) technique. MATERIALS AND METHODS: Fifteen disk specimens for the diametral tensile strength (DTS) test and fifteen cylindrical specimens for the compressive strength (CS) test were made of each GIC: Ketac-Fil, Ketac-Molar (ESPE), Fuji IX and Fuji PLUS (GC). Forty human molars were sectioned and embedded in resin with either buccal or lingual surfaces exposed for the tensile bond strength (TBS) test. The surface was ground until a flattened area of enamel or dentin was obtained. After conditioning, inverted truncated cones of GICs were prepared on the flat tooth surfaces. The powder:liquid ratio of Fuji PLUS was adjusted for restorative purposes. Prior to testing, specimens were stored for 24 h (TBS test) and for 1 h, 24 h, and 7 days (CS and DTS tests) in deionized water at 37 degrees C. They were then loaded at a crosshead speed of 1.0 mm/min for CS and 0.5 mm/min for DTS and TBS tests until failure occurred. The data were submitted to two-way ANOVA at 0.05 level of significance, followed by a Tukey-Kramer test for multiple comparisons. RESULTS: The mean CS values ranged from 90.27 to 170.73 MPa and DTS means from 6.21 to 22.32, with test periods from 1 h to 7 days. The means for TBS ranged from 4.90 to 11.36 MPa and from 2.52 to 5.55 MPa in enamel and dentin, respectively. No differences were found between materials with the CS test except at 1 hour. The resin-modified GIC (RM-GIC) had the highest DTS, with no changes between the test periods, and the highest TBS for both enamel and dentin. CONCLUSION: Among the GICs tested, RM-GIC showed higher values of DTS and TBS.

Analysis of Variance↗
PubMedDate not supplied

Evaluation of Class I ART restorations in Brazilian schoolchildren: three-year results.

Atraumatic Restorative Treatment (ART) has been adopted around the world to avoid unnecessary extractions, especially in non-industrialized countries. The development of specific glass ionomer cements marketed for the ART technique has contributed to the technical success rate. In this study, Ketac-Molar (3M ESPE, Dental Medzin, Germany) was used to restore 150 Class I cavities in 118 Brazilian public school children, aged from 7-12 years. At baseline and at subsequent recalls, CPI probes with a ball-end of 0.5 millimeters (mm) were used to assess loss of restorative material, and photographic color transparencies of restorations were made. After six months, 83 patients returned for follow-up examinations, with 71.8% of their restorations designated as acceptable. After three years, 49 patients with 57 ART-restorations were evaluated, with 21.0% of these restorations graded as acceptable. Another 29.8% of their restorations had been replaced by more permanent materials. The main objective of the ART technique is tooth retention; this was achieved for 94.7% of the restored teeth in a high caries risk population who returned for recalls.

Brazil↗
PubMedDate not supplied

Antibiotic prophylaxis in a patient with penicillin allergy and recurrent bacterial endocarditis: a case report.

Bacterial endocarditis (BE) is a rare and life-threatening heart infection that can be caused by oral microorganisms. Patients with specific cardiac valvular abnormalities as well as those with a history of recurrent episodes of endocarditis are considered to be at high-risk for developing BE. Antibiotic prophylaxis is recommended for high-risk individuals when bleeding is anticipated during dental procedures. Penicillins are the antibiotics of choice in preventing endocarditis, while other medications are indicated for patients with penicillin allergies. This case presentation outlines antibiotic prophylaxis prior to restorative care for a 44-year-old man who had a prosthetic heart valve, history of recurrent infective endocarditis and penicillin allergy. Intravenously administered vancomycin and gentamicin were prescribed due to the patients' level of risk and bleeding propensity. This article was written to raise the awareness of dental practitioners to the antibiotic prophylaxis options available for the treatment of patients with cardiac and associated systemic conditions.

Adult↗
PubMedDate not supplied

5-year clinical performance of resin composite versus resin modified glass ionomer restorative system in non-carious cervical lesions.

AIM: To comparatively assess the 5-year clinical performance of a 1-bottle adhesive and resin composite system with a resin-modified glass ionomer restorative in non-carious cervical lesions. METHOD AND MATERIALS: One operator placed 70 restorations (35 resin modified glass ionomer restorations and 35 resin composite restorations) in 30 patients under rubber dam isolation without mechanical preparation. The restorations were directly assessed by 2 independent examiners, using modified USPHS criteria at baseline and 6, 12, 24 and 60 months. RESULTS: Twenty-two patients were available for recall after 5 years (73.3% recall rate) and 55 out of 70 restorations were evaluated. Excellent agreement was registered for all criteria between examiners (kappa > or = 0.85). Sixteen composite restorations were dislodged (51.5% retention) and 1 ionomer restoration was lost (96.4% retention). The McNemar test detected significant differences in resin composite restorations between baseline and 5-year recall for marginal integrity (p<0.001) and retention (p=0.004). For resin modified glass ionomer restorations, no significant differences were identified for all criteria (p>0.05). When comparing both materials, the Fisher exact test pointed out significant differences in retention (p=0.002) after 5 years of clinical service. CONCLUSIONS: After 5 years of evaluation, the clinical performance of resin modified glass ionomer restorations was superior to resin composite restorations.

Acid Etching, Dental↗