Biomedical subjects

L D Oliveira

Publications and source records attributed to L D Oliveira.

4 recordsLinked to original sources

PubMed2005

Structural resistance in immature teeth using root reinforcements in vitro.

The purpose of this study was to evaluate in vitro the efficacy of root reinforcements by light-cured composite resin or zirconium fiber post in simulated immature non-vital teeth. Fifty-six bovine incisors teeth were used for this study. The crown of each tooth was removed in the medium third to obtain a standard length of 30 mm. The specimens were divided into four groups (n = 14): G1) the root canals were instrumented and enlarged to simulate immature non-vital teeth and were reinforced with a light-cured composite resin using a translucent curing post (Luminex system); (G2) the specimens were instrumented, enlarged and they received root reinforcement with zirconium fiber post; G3 (positive control): they received similar treatment to the G1 and G2 groups, but did not receive root reinforcement; G4 (negative control): the roots were not weakened and did not receive reinforcement. Every tooth was submitted to compressive force using an Instron testing machine with an angle of 45 degrees at a speed of 1 mm min(-1) until the fracture. The results showed a markedly increased resistance to fracture in the G1 and G2 (122.38 and 122.08 kg f, respectively). Among the results of G1 and G2 there was not any significant difference (P > 0.05) but they were significantly different from the control groups (P < 0.05). The conclusion is that the use of root reinforcements with zirconium fiber post or composite resin can increase significantly the structural resistance of the weakened teeth, decreasing the risk of the fracture.

Animals↗

PubMed2004

In vitro effects of calcium hydroxide and polymyxin B on endotoxins in root canals.

OBJECTIVES: To evaluate the effects of intracanal medicaments on endotoxins in root canals. METHODS: Seventy-five freshly extracted maxillary incisors were used in this study. The crowns of teeth were sectioned near the CEJ in order to standardize the root length to 14 mm. The root canals were instrumented to an apical size #50 file and irrigated with 1% sodium hypochlorite solution and sterilized with 60Co gamma irradiation. Standardized suspension containing Escherichia coli endotoxin was inoculated into the 60 root canals. The specimens were randomly assigned to 5 groups (n=15), according to the intracanal medicament used: (G1) calcium hydroxide; (G2) polymyxin B; (G3) combination neomycin-polymyxin B-hydrocortisone; (G4) positive control (no intracanal medicament); (G5) negative control (no endotoxin and no intracanal medicament). After 7 days, the detoxification of endotoxin was evaluated by Limulus lysate assay and antibody production in B-lymphocytes culture. RESULTS: Groups 1, 2 and 5 presented the best results by Limulus lysate and were significantly different to groups 3 and 4 (p<0.05). Stimulation of antibodies production in cell culture by groups 1 and 6 was smaller and statistically different than groups 2, 3, 4 and 5 (p<0.05). Groups 2 and 5 induced a small increase in the antibodies production in relation to the groups 1 and 6. Groups 3 and 4 induced a significant increase of antibodies production (p<0.05). CONCLUSIONS: The calcium hydroxide and polymyxin B intracanal medicaments detoxified endotoxin in root canals and altered the properties of LPS to stimulate the antibody production by B-lymphocytes. The combination neomycin-polymyxin B-hydrocortisone did not detoxified endotoxin.

Anti-Bacterial Agents↗

PubMed1999

Persistent Sydenham's chorea.

BACKGROUND: Sydenham's chorea (SC) occurs in 26% of patients with rheumatic fever (RF). Despite usually being described as a self-limited condition, few reports indicate that SC may persist in rare subjects. OBJECTIVE: To investigate the proportion of subjects with SC lasting more than 2 years and if clinical features differentiate patients with SC with a duration of less than 2 years (Group 1) from those with SC lasting more than 2 years (Group 2). METHODS: Prospective assessment of all patients with SC seen at our service from July 1993 through March 1998 analyzing the following: gender; age at onset; frequency of arthritis, carditis, family history of RF and SC; topographic distribution; and chorea severity on a 0-4 scale. RESULTS: Thirty-two patients (19 female, 13 male) were studied. In Group 1 (16 subjects, 50%) the follow-up period was 36.2 +/- 20.0 months; 50% were female; age at onset was 10.9 +/- 2.6 years; arthritis and carditis were present in 37.5% and 31.2%, respectively; family history of SC was reported by 18.7%; hemichorea was seen in 25.8% of subjects; and the mean intensity of chorea was 2.6 +/- 0.8. In Group 2, with a follow-up period of 34.1 +/- 18.9 months, 68.8% were female; age at onset was 9.3 +/- 3.9 years; arthritis and carditis were diagnosed in 18.7% and 50%, respectively; no patient reported a family history of SC; hemichorea was observed in 6.2% of subjects; and the mean intensity of chorea was 2.8 +/- 0.5. No difference was statistically significant. CONCLUSIONS: SC persists in half of our patients. Female gender, possibly related to endocrine factors, as well as the presence of carditis, indicating a more severe disease, may be risk factors for a longer duration of SC.

Acute Disease↗

PubMed1999

Hemifacial spasm and arterial hypertension.

BACKGROUND: Hemifacial spasm (HFS) is a form of segmental myoclonus often associated with vascular compression of the seventh nerve at its exit in the brain stem. Although a few uncontrolled studies describe the association of arterial hypertension (AH) with HFS, their relationship remains to be elucidated. OBJECTIVES: To compare the clinical and radiologic features of patients with HFS and subjects with blepharospasm (BLS) with special emphasis on the presence of AH. MATERIAL AND METHODS: Chart review of all patients with HFS and BLS seen at a hospital-based movement disorders clinic from July 1993 through March 1998, analyzing the following parameters: gender, age at onset, frequency of AH, and abnormalities on computerized tomography (CT) or magnetic resonance imaging (MRI) studies. Neuroimaging studies (52 CT and 14 MRI) were performed in 45 subjects with HFS and in 21 with BFS. All patients were examined by one of the authors (FC). RESULTS: HFS and BLS were diagnosed in 48 (31 women, 17 men) and 34 (28 women, 6 men) patients, respectively. The age at onset was 50.1 +/- 12.6 years in HFS and 50.3 +/- 16.5 years in BLS. AH was diagnosed in 32 (66.7%) subjects with HFS and in 13 (38.2%) patients with BLS (chi-square p = 0.01). Neuroimaging evidence of vascular tortuosity in the cerebello-pontine angle was identified in 16 (25.4%) patients, all of whom had HFS (38.1%). Thirteen of 37 patients with AH who had imaging studies displayed vascular tortuosity in the cerebello-pontine angle (chi-square p = 0.01). CONCLUSIONS: AH is significantly more common in HFS than in BLS. AH is related to vascular tortuosity in the cerebello-pontine angle. Our findings suggest that AH may be an important risk factor for HFS.

Blepharospasm↗