The crushing truth about glass ionomer restoratives: exposing the standard of the standard

ObjectivesThe compressive fracture strength (CFS) test is the only strength test for glass ionomers (GIs) in ISO 9917-1: 2003. The CFS test was the subject of much controversy in 1990 and has been challenged over its appropriateness and reproducibility and the study aimed to revisit the suitability of the CFS test for GIs.MethodsGroups of 20 (four batches of n = 5) cylinders (6.0 ± 0.1 mm height, 4.0 ± 0.1 mm diameter) of three encapsulated GIs were prepared for CFS testing using two mechanical mixing regimes and two operators. The CFS data for each GI restorative were pooled, three-, two- and one-way analyses of variance (ANOVAs) were conducted (p = 0.05) for operator, mixing regime and batch to assess reliability. The data was also analysed according to ISO 9917-1: 2003.ResultsThe three-way ANOVAs showed a significant interaction of operator × mixing regime × batch (p < 0.017) for two of the three encapsulated GIs. However, no significant effects of operator × mixing regime (p > 0.042), operator × batch (p > 0.332), mixing regime × batch (p > 0.056), operator (p > 0.094), mixing regime (p > 0.118) or batch (p > 0.054) were evident. When examined in batches of five (or ten where appropriate) as specified in ISO 9917-1: 2003, inter- and intra-operator variability were evident.ConclusionsThe use of batch-censoring in accordance with ISO 9917-1: 2003 is unsafe when the data scatter reflects a homogenous flaw distribution as it misidentifies operative variability. Despite demonstrating that the CFS test can be performed reliably, the validity of the CFS test for GIs remains under scrutiny.     

Effectiveness of second-opinion radiology consultations to reassess the cervical spine CT scans: a study on trauma patients referred to a tertiary-care hospital

PURPOSE

A second opinion is a valuable resource in confirming proper medical diagnosis and treatment. This study evaluates the effectiveness of second-opinion radiology consultations to reassess the cervical spine computed tomography (CT) scans of the trauma patients referred to our hospital.

METHODS

Cervical spine CT scans of 301 consecutive adult trauma patients, who were referred to our hospital from outside institutions, were analyzed. The emergency radiologists at our institution completed the over-read reports on the CT images obtained at the outside facilities. A single radiologist compared the outside- and over-read reports and determined the discrepancy of the radiologic reports.

RESULTS

Based on the outside reports, 31% of the CT scans had cervical traumatic injury. In 92% of patients, the first-read and the over-read reports had consistent radiologic findings. About 90% of the positive, and 93% of the negative radiologic findings, were reported consistently in the over-read reports. Our analysis showed that the over-read reporting resulted in reassurance of negative findings in 63%; confirmation of positive findings in 29%; clearing a false diagnosis in 3%; and detection of a missed diagnosis in 5%. A rescan was done in 80% of patients with inconsistent and 20% of patients with consistent findings (P < 0.05). The most common missed radiologic findings in the first-reports were transverse and spinous process fractures and the most common misdiagnoses were dens fractures.

CONCLUSION

For a service offering second-opinion consultations on cervical spine trauma, review of outside CT studies improves diagnosis and benefits patient care.The quality of healthcare has become a target of increasing public scrutiny and governmental concern while radiologic evaluation has assumed an increasingly important role in the diagnosis and management of patients (1). Public attention and awareness have increased and amplified the focus on the quality of healthcare (2). Some medical errors are extremely costly particularly with respect to patient morbidity and mortality.Patients referred to the tertiary care centers often arrive with radiologic imaging having already been performed at the primary institution. As part of the care to be delivered by the radiologists at the referral center, a second-opinion interpretation of the imaging studies is often requested, and the formal reports are incorporated into the patient’s permanent medical record at the referral institution where the patient’s management and treatment are determined.The added value of the point-of-care second interpretations can be viewed from the medical perspective of guiding and expediting appropriate treatment as well as from the financial perspective of avoiding unnecessary studies, at times incurring additional patient radiation exposure, when initial examinations need to be repeated or when additional examinations are suggested by the radiologist at an outside institution (3).Multidetector CT is an essential part of the assessment of patients suspected of having cervical spine injury after trauma. Despite all the advantages of multidetector CT, suspected spinal injury continues to be a daily challenge in clinical practice (4). Spine injuries are frequently missed; therefore, a second opinion can potentially improve the diagnosis (5). The purpose of this study was to evaluate the effectiveness of second-opinion radiology consultations to reassess the cervical spine CT scans of the trauma patients referred to our hospital.     

Can the intra-examiner variability of Little's Irregularity Index be improved using 3D digital models of study casts?

Objectives

To compare contact point displacement measurements, used to determine the Little's Irregularity Index (LII) score on study casts and digital models of study casts by an independent examiner.

Methods

The contact point displacement measurements of the six maxillary anterior labial teeth were measured on ten study casts using digital callipers and their associated digital models using Creo Parametric software on five occasions following scanning using a LAVA Chairside Oral Scanner (LCOS) three-dimensional (3D) intra oral scanner. Means, standard deviations and coefficients of variation (CoV) were determined, data analyses (Pearson's correlation coefficients (PCCs) and Intraclass correlation coefficients (ICCs)) and statistical analyses (three and two-way analyses of variance (ANOVAs) and Independent Sample Student's t-tests) were carried out (p < 0.05).

Results

Significant positive correlations for the contact point displacement measurements were evident between all measurement time points for the study casts (r > 0.978; p < 0.0001 and ICC > 0.910; p < 0.0001) and the digital models (r > 0.963; p < 0.0001 and ICC > 0.986; p < 0.0001). The CoV results showed that the contact point displacement measurement data from the digital models was more reproducible than the study casts. Of the 50 Independent Sample Student's t-tests, 21 significant increases (p < 0.042) were reported in contact point displacement measurements <2.9 mm for the digital models compared with the study casts.

Conclusion

The use of 3D digital models can improve the reliability of LII measurements by reducing the subjectivity associated with choosing the anatomic tooth contact points and the awkwardness of measuring the contact point displacements on study casts using a cumbersome calliper technique.

Clinical significance

Intra-examiner variability in the measurement of LII is still evident with digital models suggesting that either improved software specifically aimed at the orthodontic community be identified or a new method for measuring anterior incisor crowding be sought.