Fracture resistance and mode of failure of various types of root filled teeth.

AIM: To investigate ex vivo the influence of the post system on fracture resistance and failure mode of root filled incisor, canine, premolar and molar teeth. METHODOLOGY: Eighty human teeth were divided into eight groups (n = 10) resulting from the interaction between the two study factors: post system (glass fibre post; cast Ni-Cr alloy post and core) and type of tooth (maxillary incisors, maxillary canines, maxillary premolars and mandibular molars). All roots were prepared with a 2-mm ferrule and restored with metal crown. Fracture resistance (N) was assessed in a mechanical testing device, and the data were analysed by two-way anova (4 × 2) followed by Tukey's test (α = 0.05). The failure mode was evaluated using an optical stereomicroscope and classified according to the location of the failure. Failure mode data were analysed by two-factor anova and Student-Newman-Keuls (SNK) tests (α = 0.05). Correlation between fracture resistance and failure mode was analysed by linear regression. RESULTS: Glass fibre and cast posts and cores had similar fracture resistance, regardless of the type of tooth. Canines and molars had significantly higher fracture resistance (P < 0.001) than premolars. Incisors teeth had significantly lower fracture resistance (P < 0.001) than premolars. The fracture mode for incisors, premolars and molars was more amenable to restoration when the teeth were restored with glass fibre posts. Fracture resistance had no correlation with fracture mode, regardless of the post system and type of tooth analysed. CONCLUSIONS: Post system had no significant effect on fracture resistance, regardless of the type of tooth. The mode of fracture was more restorable with glass fibre posts.

Effect of gamma irradiation and restorative material on the biomechanical behaviour of root filled premolars.

AIM: To investigate ex vivo the influence of gamma irradiation therapy and restorative material on fracture resistance, fracture mode and strain of root filled human premolars. METHODOLOGY: Sixty extracted human maxillary premolar teeth were randomly divided into six groups (n = 10) determined by two study factors: (i) restorative materials: sound teeth, root filled teeth restored with composite resin, root filled teeth restored with amalgam; (ii) gamma irradiation: irradiated (subjected to 60 Gy of gamma irradiation in daily increments of 2 Gy) and nonirradiated. For the strain gauge test, two strain gauges per sample were attached on the buccal and palatal cusp surfaces (n = 5). Strain values were recorded during loading of 0-150 N. Fracture resistance (N) was assessed in a mechanical testing machine (n = 10). Strain gauge for each cusp and fracture resistance data were analysed by two-way anova (3 × 2) followed by the Tukey's honestly significant difference test (α = 0.05). The failure mode was evaluated using an optical stereomicroscope and classified according to the location of the failure. RESULTS: Gamma radiation therapy significantly reduced the fracture resistance of intact teeth. The strain was higher for teeth restored with amalgam than for those restored with composite resin. The teeth restored with composite resin had similar strain values to sound teeth. Nonirradiated teeth had more restorable failures than irradiated teeth. CONCLUSIONS: Gamma irradiation significantly reduced fracture resistance and increased cusp strain. The use of composite resin resulted in better biomechanical behaviour than amalgam for restoring root filled teeth whether or not they were submitted to radiotherapy.

Influence of post system and remaining coronal tooth tissue on biomechanical behaviour of root filled molar teeth.

AIM: To investigate ex vivo the influence of post system and amount of remaining coronal tooth tissue on the fracture resistance, fracture mode and strain of root filled molar teeth. METHODOLOGY: Seventy mandibular human molar teeth were divided into seven groups (n = 10), one control (sound teeth) and six experimental groups resulting from the interaction between the two study factors: post system (Pa, post absence; Gfp, glass fibre post; Cmp, cast Ni-Cr alloy post and core) and amount of remaining coronal tooth tissue (Fe, 2 mm of ferrule; NFe, no ferrule). Teeth in the experimental groups were restored with metal crowns. For the strain gauge test, two strain gauges per sample were attached on the buccal and proximal root surfaces, and the samples of each group (n = 5) were submitted to a load of 0-100N. Fracture resistance (N) was assessed in a mechanical testing device (n = 10). Strain gauge and fracture resistance data were analysed by two-way anova (3 × 2) followed by the Tukey's HSD and Duncan's test (α = 0.05). The failure mode was evaluated using an optical stereomicroscope and classified according to the location of the failure. RESULTS: The absence of ferrule was associated with lower fracture resistance regardless of the post system. Groups restored with glass fibre post and cast Ni-Cr alloy post and core had similar fracture resistance and higher values than groups without posts, regardless of the remaining coronal tooth tissue. Teeth with no ferrule and cast Ni-Cr alloy post and core resulted in catastrophic fractures and those with no ferrule and glass fibre post or no ferrule and post absence resulted in restorable failures. Buccal strain was higher in sound teeth and lower in teeth without posts. Glass fibre post insertion decreased the buccal strain compared to the teeth with ferrule and absence of post. CONCLUSIONS: Two millimetre of ferrule had a significant influence on cusp strain, fracture resistance and failure mode. The glass fibre post was as effective as the cast Ni-Cr alloy post and core in the restoration of root filled molars regardless of the remaining tooth tissue. Absence of a post decreased the fracture resistance and increased the cusp strain.

Effect of gamma irradiation on ultimate tensile strength of enamel and dentin.

The effect of gamma irradiation therapy on the ultimate tensile strength (UTS) of enamel and dentin in relation to prism orientation, dentin tubule orientation, and location is unknown. It was hypothesized that tubule and prism orientation, location, and irradiation have an effect on the UTS of dental structures. Forty human third molars were used, half of which were subjected to 60 Gy of gamma irradiation, in daily increments of 2 Gy. The specimens were evaluated by microtensile testing. Results showed that irradiation treatment significantly decreased the UTS of coronal and radicular dentin and of enamel, regardless of tubule or prism orientation. With or without irradiation, enamel was significantly stronger when tested parallel to its prismatic orientation. Coronal and radicular dentin of non-irradiated specimens presented significantly higher UTS when tested perpendicularly to tubule orientation. However, when the teeth were irradiated, the influence of tubule orientation disappeared, demonstrating that irradiation is more harmful to organic components.

Effects of post system and length on the strain and fracture resistance of root filled bovine teeth.

AIM: To investigate ex vivo the effects of different post systems and lengths on the strain and fracture resistance of root-filled teeth. METHODOLOGY: One hundred and thirty-five bovine incisors were sectioned 15 mm from their apices, root-filled and divided into three groups (n = 45): fibreglass post; prefabricated steel post; cast post and core. Each group was divided into three subgroups (n = 15) according to the post length: 5.0 mm; 7.5 mm; 10.0 mm. All teeth were restored with metal crowns. For strain-gauge measurement, two strain gauges per sample were used. The fracture resistance (N) was measured and the data were analysed with two-way analyses of variance, followed by the Tukey's HSD test (alpha = 05). RESULTS: For all posts, decreased lengths resulted in increased microstrain values. However, the fibreglass posts were associated with lower increases when compared with cast post and cores and prefabricated steel posts, which showed microstrain values two times higher when the post length was 5.0 mm. The two-way analyses of fracture resistance values revealed that post length was statistically significant for the metal posts and not significant for the fibreglass post. The fracture mode analysis indicated that all groups tended to demonstrate root fractures in groups restored with metal posts and resin core fractures in groups restored with fibreglass posts. CONCLUSIONS: The cast post and core when the length was 10.0 mm had the highest fracture resistance; however, the fibreglass post was effective with the three post lengths, with higher fracture resistance than metal posts when the length was 5.0 mm.

Bacterial contamination of blenderized whole food and commercial enteral tube feedings in the Philippines.

Hospital-prepared tube feedings from four Philippine acute-care hospitals were analysed for microbial contamination. Two feedings were prepared on three separate days at each hospital. The tube feedings were either blended natural whole foods or a reconstituted commercial powdered nutritional product. Samples of each feeding were collected for coliform count and standard plate count at the time of preparation and at 1, 2 and 4 h after preparation after maintenance at room temperature (26-31 degrees C). At the time of preparation, mean coliform and standard plate counts for all samples were 10.3 most probable number per gram (MPN/g) and 7.4x10(4)colony-forming units per gram (cfu/g), respectively. Nine of 24 samples (38%) had coliform counts greater than 10 MPN/g, and 22/24 (92%) samples had standard plate counts greater than 10(3) cfu/g. There were significant increases in mean coliform and standard plate counts over 4 h (P=0.0005 and P=0.008, respectively). At 4 h after preparation, the mean coliform and standard plate counts were 18.2 MPN/g and 2.1x10(5) cfu/g, respectively. At this time, 18/24 (75%) samples had coliform counts greater than 10 MPN/g and 20/24 (83%) samples had standard plate counts greater than 10(5) cfu/g. The results of this study show that the microbial quality of the majority of the hospital-prepared enteral tube feedings analysed were not within published guidelines for safety.

von Willebrand factor antigen levels in plasma of patients with malignant breast disease.

von Willebrand factor (vWF) is a protein that mediates platelet adherence to the subendothelium during primary hemostasis. High plasma vWF concentrations have been reported in patients with various types of cancer, such as head and neck, laryngeal and prostatic cancer, probably representing an acute phase reactant. In the present study we determined the plasma levels of vWF antigen (vWF:Ag) by quantitative immunoelectrophoresis in 128 female patients with breast cancer as well as in 47 women with benign breast disease and in 27 healthy female controls. The levels of vWF:Ag were 170.7 +/- 78 U/dl in patients with cancer, 148.4 +/- 59 U/dl in patients with benign disease and 130.6 +/- 45 U/dl in controls (P<0.005). We also detected a significant increase in the levels of vWF:Ag (P<0.0001) in patients with advanced stages of the disease (stage IV = 263.3 +/- 113 U/dl, stage IIIB = 194.0 +/- 44 U/dl) as compared to those with earlier stages of the disease (stage I = 155.3 +/- 65 U/dl, stage IIA = 146.9 +/- 75 U/dl). In conclusion, vWF levels were increased in plasma of patients with malignant breast disease, and these levels correlated with tumor progression.

[Interaction between prescribers, dispensers, and patients: shared information as a possible therapeutic benefit]. / A interação entre prescritores, dispensadores e pacientes: informação compartilhada como possível benefício terapêutico.

The article presents a critical view of the interaction between prescribers, dispensers, and patients, considering information one of the key issues in enhancing the qualitative aspects involved in this complex relationship. It describes the acquisition of information by health professionals, possible sources of this information, and the process involved in transforming it into knowledge. Briefly discussed are the physician's and pharmacist's roles, the patient's expectations as recipient, and consequences of pertinent health interventions.

[Pharmaceutical procurement by the public sector: the quality/cost relationship]. / Aquisição de medicamentos no setor público: o binômio qualidade - custo.

The authors discuss procurement and provision of pharmaceutical products from the perspective of supply management in the public health sector, focusing on two main aspects: quality and cost. The article analyzes issues to be considered by buyers when evaluating drug quality, especially formulation stability, bioequivalence, and the role of generics. Also discussed are factors involving costs and cost management in relation to technological innovations and consumer demands. New alternatives and suggestions are examined and presented for procurement of high-quality, cost-effective drug products.

[Food and nutrition knowledge of school-age children's mothers from elementary and high school from different socioeconomic levels]. / Conocimientos alimentarios y nutricionales de madres de escolares de educación básica y media de diferentes niveles socioeconómicos.

The objective of this study was to determine the degree of knowledge on food and nutrition of school-age children's mothers from Chile's Metropolitan Region and to measure the impact of socioeconomic, sociocultural and demographic variables on knowledge. A representative and proportional sample of 4,509 school-age children was chosen from Chile's Metropolitan Region and the degree of knowledge on food and nutrition on mothers of 1,985 of them was determined. The sample was stratified according to grade (I, II, IV, VI, VIII elementary school grades and I and IV high school grades), sex, type of school and geographic area. Socioeconomic status (SES) was determined through Graffar's modified method. The degree of knowledge on food and nutrition was assessed by a test based on the specific objectives pursued by the elementary school curriculum programs of the Ministry of Education and submitted to adequate statistical proofs for its content validity and reliability. Mother's schooling level mean was 9.7 +/- 4.0 y. The field study was carried out on 1986-1987. Statistical procedures included analysis of variance, Student "t" test for comparison of the means, correlation and regression. Results revealed that mothers did not know food and nutrition matters in fundamental aspects related to the observance of a healthy lifestyle, both, for themselves and their family. The degree of knowledge of food and nutrition significantly and positively correlated with SES, mother's schooling and occupation level, housing conditions (quality and sanitation) and age, and significantly and inversely correlated with the number of sons and crowding, besides of being significantly higher in urban than rural mothers. Mother's schooling level and geographic area were the independent variables with the greatest explanatory power in the food and nutrition knowledge variance (r2 = 0.1723), but mother's schooling level explains 93.2% of the explained variance. Results suggest the need to introduce, during school age, nutrition education programs focused on mother and children to improve the population life quality.

[Food and nutrition knowledge of elementary and high school-age children from Chile's Metropolitan Region]. / Conocimientos alimentarios y nutricionales de escolares de educación básica y media de la Región Metropolitana de Chile.

BACKGROUND: In Chile there is scarce food and nutrition knowledge among school age children. AIM: To determine the degree of food and nutrition knowledge of elementary and high school children and its relationship to socioeconomic status, sex, type of school and geographic area. SUBJECTS AND METHODS: Between 1986 and 1987, a representative and proportional sample of 4509 children was chosen from the Metropolitan Region. This sample was stratified according to school grade, sex, type of school and geographical area. Graffar's modified method was used to measure socioeconomic status. Food and nutrition knowledge was assessed by a specific test for each grade, based on the objectives pursued by the curricular programs of the Ministry of Education. RESULTS: The test was applied to 4197 children. Food and nutrition knowledge was significantly lower in the second subcycle of elementary school, in males, in older children from each grade, in rural areas, in children of low socioeconomic status and in public schools. CONCLUSIONS: School age children were unaware of fundamental aspects related to food and nutrition and curriculum programs of the Ministry of Education should be reformulated to overcome these deficiencies.

Nutrition and learning in Chilean school age children: Chile's Metropolitan Region Survey 1986-1987.

The objective of this study was to determine the interrelationship between the scholastic achievement (SA) test and nutritional status of a representative sample of 4,509 elementary and high school children from Chile's Metropolitan Region. Percentages of weight/age (W/A), height/age (H/A), and weight/height (W/H) were compared to WHO (World Health Organization) Tables, head circumference/age (HC/A) to the Tanner Tables, and brachial anthropometry to Frisancho's norms. Socioeconomic status (SES) was measured by means of Graffar's Modified Method; SA by means of a language and mathematics test. Statistical analysis included correlation, regression, and WHO risk-approach methodology. Results showed that HC/A was the anthropometric parameter with the greatest explanatory power in SA variance and was significantly greater in high school graduates who were 17 y old (r = 0.350; p < 0.001; r2 = 0.122) than in elementary school children, who were 6 y old (r = 0.227; p < 0.001; r2 = 0.049), with a relative risk of 2.1 and 1.5, respectively. The explanatory power of W/A and H/A in SA variance was significantly decreased, and no significant differences were observed among high school students. These findings confirm that HC/A is the most important anthropometric parameter associated with SA. Educational selectivity apparently relates to HC/A, and not to W/A or H/A. These results may be useful in planning nutritional and educational policies.

Evolution of ambulatory pharmacy services at a public health department.

This article is a narrative of the development of several key pharmacy services at a public health department in a metropolitan area fraught with many urban problems and obstacles for delivery of health services to the underserved. The pharmacy operation evolved from a traditional dispensing role to fully integrated clinical pharmacy services.