Prevalence of vertical root fractures in teeth planned for apical surgery. A retrospective cohort study.

AIM: To evaluate retrospectively the prevalence of vertical root fractures (VRFs) in a cohort of patients during apical surgery and the factors possibly associated with VRF. METHODOLOGY: The sample consisted of 944 root filled teeth belonging to 768 patients (49.3% males and 50.7% females; mean age 43.5 ± 11.2 years, range 22-68 years), consecutively referred for endodontic surgery over a six-year period. All patients underwent a clinical assessment of their signs and symptoms. Periapical radiographs of teeth that were candidates for endodontic surgery were taken. Sixty-eight teeth with VRF were identified. Vertical root fractures were identified in pre-surgical screenings in 32 cases (47.1%), and these did not undergo surgery. Another 36 cases of VRF were noted during the intervention for root-end resection. The influence of posts, post type, tooth type, periodontal probing defects, spontaneous pain, sinus tract and follow-up duration was assessed using a logistic regression analysis. RESULTS: Vertical root fractures occurred significantly more frequently (P < 0.001) when a post was present (61 VRF out of 377 teeth with post, prevalence 16.2%) than in teeth without a post (1.2%). Threaded posts and cast posts were significantly more involved in VRF than fibre, silica or carbide posts (P < 0.001). Most fractures (80.9%) occurred 1-5 years after root canal treatment. Sinus tracts, probing defects and spontaneous pain were significantly more associated with VRF cases than with nonfractured teeth. CONCLUSIONS: In the present group of teeth, the major risk for VRF was represented by posts retained by actively engaging the canal via mechanical design (thread) or by frictional fit (cast).

Reference values for respiratory rate in the first 3 years of life.

BACKGROUND: Raised respiratory rate is a useful sign to diagnose lower respiratory infections in childhood. However, the normal range for respiratory rate has not been defined in a proper, large sample. OBJECTIVE: To assess the respiratory rate in a large number of infants and young children in order to construct percentile curves by age; to determine the repeatability to the assessment using a stethoscope and compare it with observation. METHODS: Respiratory rate was recorded for 1 minute with a stethoscope in 618 infants and children, aged 15 days to 3 years old, without respiratory infections or any other severe disease when awake and calm and when asleep. In 50 subjects we compared respiratory rate taken 30 to 60 minutes apart to assess repeatability, and in 50 others we compared simultaneous counts obtained by stethoscope versus observation. RESULTS: Repeatability was good as the standard deviation of differences was 2.5 breaths/minute in awake and 1.7 breaths/minute in asleep children. Respiratory rate obtained with a stethoscope was systematically higher than that obtained by observation (mean difference 2.6 breaths/minute in awake and 1.8 breaths/minute in asleep children; P = .015 and P < .001, respectively). A decrease in respiratory rate with age was seen for both states, and it was faster in the first few months of life when also a greater dispersion of values was observed. A second degree polynomial curve accurately fitted the data. Reference percentile values were developed from these data. CONCLUSIONS: The repeatability of respiratory rate measured with a stethoscope was good. Percentile curves would be particularly helpful in the first months of life when the decline in respiratory rate is very rapid and prevents to use cut off values for defining "normality."

Erythrocyte superoxide dismutase, catalase and glutathione peroxidase activities in beta-thalassaemia (major and minor).

The 'antioxidant' enzymes superoxide dismutase (SD), catalase and glutathione peroxidase (GSH-Px) were found greatly elevated in red blood cells of subjects with beta-thalassaemia minor and similar to normal values in red blood cells of subjects with beta-thalassaemia major. These findings allows us to speculate that red cells in beta-thalassaemia minor react to the increased oxidant threat with augmented antioxidant enzyme activities. The normal levels of antioxidant enzymes in beta-thalassaemia major seem to be due to the presence of normal red cells owing to multiple transfusions.