Fracture behavior of structurally compromised non-vital maxillary premolars restored using experimental fiber reinforced composite crowns

PURPOSE: To study the fracture behavior of direct resin composite crowns with or without experimental fiber reinforcement. METHODS: Clinical crowns of single-rooted maxillary premolars were cut off at the cemento-enamel junction. Canals were prepared with Gates Glidden drills up to size 4. No additional post-space preparations were made. Roots were embedded in acrylic and canal entrances were standardized (depth 2 mm, diameter 1.75 mm). Three groups of 14 samples were treated as follows: (1) custom-made glass FRC post (EverStick Post); fibers 5 mm deep in the canal, (2) similar post-system as (1) with incorporation of a new type of glass fiber fabric, (3) no fiber reinforcement (control). Posts were cemented with resin cement (Panavia F). Resin composite crowns (Filtek Z250) were made using an anatomically formed mold. Static load until fracture was applied using a universal loading device with a cylindrical bar (diameter 2 mm) with a crosshead speed of 5 mm/minute (loading angle: 30 degrees to the tooth long-axis). Failure modes were categorized as favorable and unfavorable failures. RESULTS: There was no significant difference in mean failure loads among the four groups (P > 0.05). Favorable failures occurred significantly more often in Group 2 than in the other groups (P < 0.05). The results suggest that an incorporated glass fiber fabric does not affect the load-bearing capacity of resin composite complete crowns on structurally compromised and non-vital premolars. Incorporation of a glass fiber fabric, however, has a beneficial effect on the failure mode.     

Quality of marginal adaptation evaluation of posterior composites in clinical trials

The evaluation of margins of restorations in clinical trials relies on the subjective assessment of evaluators, with no instrument having been developed, let alone validated, to assist in the process. The purpose of the present study was to assess the quality of evaluations of marginal adaptation by analyzing the distribution of marginal steps rated according to clinical criteria. Replicas of 435 restorations, the marginal qualities of which had been evaluated according to modified USPHS criteria, were randomly selected from the Occlusin multi-center clinical trial program. The marginal step height in the most deteriorated area of each restoration was measured by means of a digital step-height instrument. An overlap between the steps in the restorations with A (Alfa; replacement unnecessary) and B (Bravo; replacement questionable) ratings was found to be in the range of 101 microm to 321 microm. When the steps with a height greater or less than one standard deviation of the mean were excluded, the overlap was reduced to a range of 168 micro m to 173 microm. This finding indicates a marginal height boundary between A and B ratings for marginal adaptation of 170 +/- 3 microm.     

Human immunodeficiency virus-associated Kaposi sarcoma as an immune reconstitution inflammatory syndrome: a literature review and case report

BACKGROUND: Kaposi sarcoma (KS) is the most common human immunodeficiency virus (HIV)-associated neoplasm (HIV-KS). Highly active antiretroviral therapy (HAART) results in a decrease in the incidence and prevalence of HIV-KS as well as in clinical improvement. However, in a subset of subjects who are HIV seropositive, KS may recrudesce early following the introduction of HAART as an immune reconstitution inflammatory syndrome (IRIS). METHODS: The management of a patient who is HIV seropositive with rapid clinical worsening of oral KS lesions shortly after the initiation of HAART was documented. Repeated serologic testing for CD4(+) T-cell count and microscopic examination of two biopsy specimens of the oral lesion, one taken before and the other taken after cytotoxic chemotherapy, followed by surgical excision was the treatment modality used. RESULTS: Microscopic examination of the incisional biopsy specimen taken from the oral lesion at the time of the initial consultation confirmed the clinical diagnosis of KS. The sequential serological tests showed a progressive increase in CD4(+) T-cell counts that paralleled the rapid clinical worsening of the KS disease. This was consistent with the diagnosis of IRIS-associated HIV-KS. Subsequent cytotoxic chemotherapy brought about resolution of the IRIS and regression of the HIV-KS lesions. Microscopic examination of a biopsy specimen obtained after cytotoxic chemotherapy did not show any of the original KS. The residual palatal exophytic mass was excised. CONCLUSIONS: IRIS-associated HIV-KS is not a disease, but rather a temporary paradoxical immunoinflammatory reaction brought about by improvement in immune status following HAART. IRIS-associated HIV-KS can be controlled effectively by limited systemic cytotoxic chemotherapy in the setting of HAART.     

The nature of the remaining dentin surface following application of Carisolv solution

PURPOSE: To evaluate the effect of Carisolv solution on the topography and surface hardness of dentin. METHODS: Two separate studies were carried out. Atomic force microscopy (AFM) was employed to visualize dentin surface topography on slices of previously extracted non-carious and carious teeth following the passive application of Carisolv gel for 30- and 60-second periods. A Wallace hardness instrument was used to measure the dentin surface hardness following active caries removal with Carisolv gel and the specially designed instruments. Conventional caries removal with dental burs and non-carious dentin acted as controls for the latter study. RESULTS: AFM revealed that the passive application of Carisolv gel resulted in smoother surfaces than observed on carious and non-carious dentin. There was a statistically significant difference between the mean hardness values for non-carious and Carisolv-treated dentin (P< 0.05). There was no statistically significant difference between the non-carious and bur-treated dentin nor the Carisolv and bur-treated dentin.     

Chondrosarcoma of the mandible: a case report

Chondrosarcomas are malignant tumours of cartilaginous origin. They range from a well-differentiated growth resembling a benign cartilage tumour to a high-grade malignancy with aggressive local behaviour and the potential to metastasize. Only 5% to 10% of chondrosarcomas are known to occur in the head and neck region. A case of chondrosarcoma of the anterior region of the mandible is presented, along with a review of the relevant literature.     

Root and canal morphology of permanent mandibular molars in a Sudanese population

AIM: To investigate variations in the root canal systems of first and second permanent mandibular molar teeth in a Sudanese population using a clearing technique. METHODOLOGY: Two hundred extracted first and second permanent mandibular molars from three cities in the state of Khartoum were studied. Access cavities were prepared and pulp tissue was removed by immersion in 5% sodium hypochlorite under ultrasonication; Indian ink was then injected into the root canal systems assisted by a vacuum applied apically. The teeth were rendered clear by demineralization and immersion in methyl salicylate before evaluation. The following observations were made (i) number of roots and their morphology; (ii) number of root canals per tooth; (iii) number of root canals per root and (iv) root canal configuration. RESULTS: Overall 59% of mandibular first molars had four canals with 3% having a third distolingual root. Seventy-eight per cent of second mandibular molars had two separate flat roots, whilst 10% were C-shaped. The most common canal system configurations were type IV (73%) and type II (14%). Inter-canal communications were more common in the mesial roots. The prevalence of inter-canal communications was 65% in first molars and 49% in second molars. CONCLUSIONS: In this sample of Sudanese teeth, 59% of the mandibular first permanent molars had four root canals whilst 10% of the mandibular second molars had C-shaped roots/canals.     

Automatic detection of left ventricular ejection time from a finger photoplethysmographic pulse oximetry waveform: comparison with Doppler aortic measurement

Left ventricular ejection time (LVET) is a useful measure of ventricular performance and preload. The present study explores a novel method of continuous LVET monitoring using a noninvasive finger photoplethysmographic pulse oximetry waveform (PPG-POW). A method for the automatic beat-to-beat detection of LVET from the finger PPG-POW is presented based on a combination of derivative analysis, waveform averaging and rule-based logic. The performance of the detection method was evaluated on 13 healthy subjects during graded head-up tilt. Overall, the correlation between the PPG-POW derived LVET and the aortic flow derived LVET was high and significant (r = 0.897, p < 0.05). The bias was -14 +/- 14 ms (mean +/- SD), and the percentage error was 9.7%. Although these results would not be sufficient to satisfy the requirement for clinical evaluation of LVET when absolute accuracy was demanded, the strong correlation between the PPG-POW LVET and the aortic LVET on an intra-subject basis (r = 0.945 +/- 0.043, mean +/- SD) would support the application of PPG-POW to detect the directional change in LVET of an individual. This could be very useful for the early identification of progressive hypovolaemia or blood loss. The present study has demonstrated a promising approach to extract potentially useful information from a noninvasive, easy-to-obtain signal that could be readily acquired either from existing patient monitoring equipment or from inexpensive instrumentation. More extensive investigation is necessary to evaluate the applicability of the present approach in clinical care monitoring.     

CCR10 expression is a common feature of circulating and mucosal epithelial tissue IgA Ab-secreting cells

The dissemination of IgA-dependent immunity between mucosal sites has important implications for mucosal immunoprotection and vaccine development. Epithelial cells in diverse gastrointestinal and nonintestinal mucosal tissues express the chemokine MEC/CCL28. Here we demonstrate that CCR10, a receptor for MEC, is selectively expressed by IgA Ab-secreting cells (large s/cIgA(+)CD38(hi)CD19(int/-)CD20(-)), including circulating IgA(+) plasmablasts and almost all IgA(+) plasma cells in the salivary gland, small intestine, large intestine, appendix, and tonsils. Few T cells in any mucosal tissue examined express CCR10. Moreover, tonsil IgA plasmablasts migrate to MEC, consistent with the selectivity of CCR10 expression. In contrast, CCR9, whose ligand TECK/CCL25 is predominantly restricted to the small intestine and thymus, is expressed by a fraction of IgA Ab-secreting cells and almost all T cells in the small intestine, but by only a small percentage of plasma cells and plasmablasts in other sites. These results point to a unifying role for CCR10 and its mucosal epithelial ligand MEC in the migration of circulating IgA plasmablasts and, together with other tissue-specific homing mechanisms, provides a mechanistic basis for the specific dissemination of IgA Ab-secreting cells after local immunization.     

Effects of blood pressure lowering and metabolic control on systolic left ventricular function in Type II diabetes mellitus

Decreased left ventricular long-axis function may be the earliest stage in subclinical heart failure in Type II diabetes. To assess whether a decrease in SBP (systolic blood pressure) or a change in metabolic control would improve the long-axis function, 48 Type II diabetic patients participating in the CALM II (Candesartan and Lisinopril Microalbuminuria II) study were included in the present study. Patients were examined with tissue Doppler echocardiography at baseline and after 3 and 12 months of follow-up. Corresponding blood pressure, fructosamine and HbA(1c) (glycated haemoglobin) values were obtained. During the follow-up period, a decrease in SBP of 8 mmHg was seen (from 141+/-11 mmHg at baseline to 133+/-12 mmHg; P<0.001) and the peak systolic strain rate was significantly improved (from -1.10+/-0.25 at baseline to -1.25+/-0.22; P<0.01). There was a highly significant relationship between the changes in systolic strain rate, HbA(1c) (P<0.001) and fructosamine (P<0.05), and similarly to changes in left ventricular mass (P<0.05), whereas the correlation to the SBP reduction was not significant. Patients with improved glycaemic control, defined as a reduced HbA(1c) value after 12 months of follow-up, had a significantly improved strain rate (from -1.07+/-0.3 s(-1) at baseline to -1.32+/-0.25 s(-1); P<0.01) compared with patients with increases in HbA(1c) (from -1.14+/-0.25 s(-1) at baseline to -1.16+/-0.27 s(-1); P=not significant). The two groups had comparable baseline values of SBP, left ventricular mass, age and disease duration. In conclusion, changes in left ventricular systolic long-axis function are significantly correlated with changes in left ventricular mass, as well as metabolic control, in hypertensive patients with Type II diabetes mellitus.