Fracture resistance of compomer and composite restoratives

This study evaluated and compared the fracture toughness of compomers and composites. Three compomer (Compoglass F [CG], Vivadent; F2000 [FT], 3M-ESPE; Dyract Posterior [DP], Dentsply) and three composite (Tetric Ceram [TC], Vivadent; Z250 [ZT], 3M-ESPE; Esthet X [EX], Dentsply) restoratives were selected for the study. Single-edged notched specimens (25 x 2 x 2 mm) were fabricated according to manufacturers' instructions and conditioned in distilled water at 37 degrees C for one week prior to testing. Seven specimens were made for each material. The specimens were loaded to failure using an Instron microtester with a crosshead speed of 0.5 mm/minute. Data were subjected to ANOVA/Scheffe's test and Independent Samples T-test at significance level 0.05. The mean fracture toughness (K(IC)) ranged from 0.97 to 1.23 MPam 1/2 for compomers and 1.75 to 1.92 MPam 1/2 for composites. The fracture toughness of compomers was significantly lower than their composite counterparts. No significant difference in K(IC) values was observed among the different composites. When the compomers were compared, FT had significantly higher fracture toughness than DP and CG. In view of their poorer resistance to crack propagation, compomers are not recommended for use in stress-bearing areas.     

Effects of different fluoride recharging protocols on fluoride ion release from various orthodontic adhesives

Objective

The purpose of this study was to find the most effective fluoride recharging protocol for orthodontic adhesives.

Methods

Five orthodontic adhesives were used: a non-fluoride-releasing composite, a fluoride-releasing composite, a polyacid-modified composite (compomer), and two resin-modified glass-ionomer cements (RMGICs). Each specimen was placed into deionized water (DW) and the initial fluoride ion release was measured for 2 months. Each specimen was then subjected to four different treatments to simulate a fluoride recharge: 1000 ppm NaF solution, acidulated phosphate fluoride gel (APF), fluoride-containing dentifrice and DW (control). After topical fluoride treatment, each specimen was submitted to fluoride re-release tests.

Results

Fluoride-containing adhesives initially showed higher rates of fluoride ion release, but significantly declined to lower levels. The overall cumulative fluoride ion release during the initial period was RMGICs > compomer > fluoride-containing composite > non-fluoride-releasing composite. After topical fluoride treatment, the amount of fluoride ion re-released was proportional to the amount of fluoride ion previously released from the adhesives. However, the amount of fluoride ions released only lasted for 2 days and then returned to the levels before fluoride application. The overall cumulative fluoride ion re-release according to the fluoride treatments was APF and NaF solution > dentifrice.

Conclusion

This study suggests that using the combination of RMGICs and a fluoride-containing mouth rinse solution is the most effective protocol for long-term fluoride re-release from orthodontic adhesives, given the difficulty of routine use of APF at home, although all topical fluoride treatments can recharge fluoride ion in adhesives.     

Determination of vertical dimension of dental occlusion

Principles and concepts in determining the vertical dimension of occlusion in mutilated dentitions are summarized. Historically, most concepts have been developed for full dentures. However, in the rehabilitation of a mutilated dentition it is often necessary to increase or change the vertical dimension of occlusion. If the vertical dimension of occlusion has to be altered the patient's adaptability to the new position should be tested during a trial period. Determination of the vertical dimension of occlusion is apparently a combination of art, science and experience.     

Weekend catch-up sleep is independently associated with suicide attempts and self-injury in Korean adolescents

The current study aims to determine the associations of insufficient sleep with suicide attempts and self-injury in a large, school-based Korean adolescent sample.     

Comparison of subgroups based on hemorrhagic lesions between SWI and FLAIR in pediatric traumatic brain injury

Purpose

The purpose of this study was to investigate efficient ways to diagnose and predict clinical outcomes for childhood traumatic brain injury.

Methods

Hemorrhagic signal intensities in nine brain regions were observed using axial fluid-attenuated inversion recovery (FLAIR) and susceptibility-weighted imaging (SWI). After having divided the subjects into mild presentation (GCS 14–15) and moderate-to-severe presentation groups (GCS ≤13), we divided the patients into three subgroups: Subgroup I, hemorrhagic foci observed only on SWI and not on FLAIR; Subgroup II, hemorrhagic foci observed on both SWI and FLAIR in the same brain regions; and Subgroup III, any cases with additional foci on SWI in other brain regions. We investigated the clinical course and compared lesion numbers and distributions of hemorrhagic lesions on SWI among the subgroups.

Results

Three clinical variables (hospitalization period in intensive care unit, total days of hospitalization, and outcome based on Pediatric Cerebral Performance Category Scale score) showed significant relevance to the three subgroups. Subgroup I showed the fewest lesions followed by Subgroups II and III, respectively. In all three subgroups, lesions were most abundant in cortical regions. Lesion in the thalamus, basal ganglia, corpus callosum, and brainstem was least in Subgroup I and gradually increased in Subgroups II and III. Such distinction was more significant in the moderate-to-severe group when compared with the mild group.

Conclusions

In cases of pediatric traumatic brain injury, categorizing patients into one of the above three subgroups based on hemorrhagic lesions on SWI and FLAIR is a promising method for predicting patient’s clinical outcome.     

Reduction cranioplasty for macrocephaly with long-standing hydrocephalus and non-fused fontanelle in Chiari malformation type I

Introduction

Because hydrocephalus is diagnosed and treated at an early stage in pediatric patients, pediatric neurosurgeons rarely encounter patients with hydrocephalic macrocephaly. There are even fewer cases of infants with long-standing hydrocephalus in whom macrocephaly progresses and is accompanied by skull defect due to malunion of suture lines despite long-term CSF diversion treatment.

Case report

We report the case of a male infant with Chiari malformation type I who presented with congenital hydrocephalus and occipital encephalocele that progressed to hydrocephalic macrocephaly with frontal skull defect, despite numerous cerebrospinal fluid diversion operations. The patient eventually recovered successfully after reduction cranioplasty.     

Clinical Outcomes in Patients with Non-Diagnostic Thyroid Fine Needle Aspiration Cytology: Usefulness of the Thyroid Core Needle Biopsy

Background

Patients with non-diagnostic thyroid fine needle aspiration cytology (FNAC) results undergo repeat FNAC or core needle biopsy (CNB) for definite diagnosis or surgical resection, or are followed up by clinical and ultrasound surveillance. We aimed at evaluating the risk of malignancy in patients with non-diagnostic FNACs and their clinical outcomes according to the follow-up modality.

Methods

We retrospectively reviewed 1,496 (8.8 %) cases with a non-diagnostic result on a first aspiration among 17,045 thyroid FNACs performed between October 2008 and August 2012. Of the non-diagnostic FNACs, 389 patients underwent a second FNAC; 125, CNB; and 89, thyroidectomy by clinical indication. The remaining patients were clinically followed up.

Results

The rate of a second non-diagnostic result was significantly higher on repeat FNAC than on CNB (33.2 vs. 2.4 %; p < 0.001). There was no significant difference in the malignancy risk among patients initially non-diagnostic, twice non-diagnostic, and thrice or more non-diagnostic, nor did this differ from the rate following CNB. No further malignancy was found in cases with ≥2 non-diagnostic CNBs. The malignancy risk was 51 % in those who underwent thyroidectomy. The sensitivity for detecting malignancy was 65 and 70 % for repeat FNACs and first CNBs, respectively, with no false positives seen in either test.

Conclusions

Approximately one-third of repeat FNACs after an initial non-diagnostic aspirate are non-diagnostic on repeat examination, and the malignancy risk may not reduce following repetitively non-diagnostic FNACs. However, a single CNB may be enough to exclude malignancy risk for patients with a non-diagnostic aspirate.     

Comparison between high and low molecular weight hyaluronates in knee osteoarthritis patients: open-label, randomized, multicentre clinical trial

Efficacy and safety of high and low molecular weight hyaluronates in knee osteoarthritis patients were compared in a randomized, open-label trial. Patients in the high molecular weight hyaluronate group were treated once weekly for 3 weeks and in the low molecular weight group once weekly for 5 weeks. We evaluated weight-bearing pain, degree of flexion, swelling and knee tenderness; frequency and amount of rescue medication; patient and investigator global assessment of pain, and safety over 12 weeks after final injection of study medication. Significant improvements in pain and WOMAC-Likert scores were observed in both groups, but not between groups. Knee joint pain improvement was noted in both groups by patients and investigators during follow-up. Close correlation was observed between patient- and investigator-reported data. There was no significant difference in side-effects between the groups. In conclusion, the efficacy and safety of high and low molecular weight hyaluronate are similar.