Comparison of Fit Between Zirconia and Metal Copings Fabricated Conventionally or Using Different CAD/CAM Techniques.

This study was designed to assess the fit of cobalt chromium copings fabricated using direct metal laser sintering and to compare with copings fabricated from nickel chromium (traditional casting) and zirconia (milled from partially sintered blanks). For both cobalt chromium and zirconia groups, impressions were generated using direct or indirect digitization. There were 5 experimental groups of 12 copings fabricated for a prepared maxillary right molar. The intimacy of fit (measured at the margin, axial wall and occlusal) was assessed using a replica method technique. The results showed that zirconia copings produced using direct digitization had significantly smaller marginal, axial and occlusal measurements compared to other groups (p⟨0.05). Nevertheless, all groups had a mean marginal gap within accepted clinical values. Though there was a decrease in the intimacy of fit from the margin to axial wall to the occlusal surface. It can be concluded that the fit of zirconia copings fabricated using direct digitization was significantly better than the other groups. However, it can be expected that further enhancement and refinement of additive technology such as direct metal laser sintering will offer clinicians a viable alternative to nickel chromium analogue production methods in the future.

Improving survival without reducing quality of life in small-cell lung cancer patients by increasing the dose-intensity of chemotherapy with granulocyte colony-stimulating factor support: results of a British Medical Research Council Multicenter Randomized Trial. Medical Research Council Lung Cancer Working Party.

PURPOSE: The treatment of small-cell lung cancer patients with good performance status aims to improve survival. Dose-intensification could be a way to achieve improved survival but can be limited by neutropenia and thrombocytopenia. Preliminary, nonrandomized feasibility studies showed that doxorubicin, cyclophosphamide, and etoposide (ACE) could be given every 2 (instead of the usual 3) weeks with granulocyte colony-stimulating factor (G-CSF) (lenograstim; Chugai-Rh¿one-Poulenc, Tokyo, Japan) support. The present multicenter randomized trial was designed to examine whether such dose-intensification improves survival while maintaining acceptable toxicity levels. PATIENTS AND METHODS: All patients were randomized to receive six cycles of ACE either every 3 weeks (control [C] group) or every 2 weeks with G-CSF (G group). The standard dose-intensity of ACE was increased by 50% in group G. RESULTS: Four hundred and three patients (G group: n = 201; C group: n = 202) were randomized. The received dose-intensity was 34% higher in the G group than in the C group. Complete response rates were 40% for the G group and 28% for the C group (P =.02), and overall rates were 78% for the G group and 79% for the C group. Survival was longer in the G group (hazard ratio = 0.80; 95% confidence interval, 0.65 to 0.99; P =.04), survival rates for the G and C groups being 47% and 39% at 12 months and 13% and 8% at 24 months, respectively. Metastasis-free survival, nonhematologic toxicity, and quality of life were similar in the two groups. In the G group, there was less neutropenia but more thrombocytopenia and more frequent blood and platelet transfusions. CONCLUSION: Increasing the dose-intensity of ACE with G-CSF support improved survival while maintaining acceptable toxicity.

Treatment of endotracheal or endobronchial obstruction by non-small cell lung cancer: lack of patients in an MRC randomized trial leaves key questions unanswered. Medical Research Council Lung Cancer Working Party.

Symptoms of endotracheal or endobronchial obstruction caused by non-small cell lung cancer (NSCLC) may be relieved with external beam radiotherapy (XRT) or endobronchial treatment. The comparative roles of these two methods need to be established. Patients with predominantly intraluminal obstruction of the trachea, a main bronchus or a lobar bronchus by unresectable NSCLC were randomized to XRT versus the clinician's choice of endobronchial treatment with brachytherapy, laser resection or cryotherapy, according to local availability and practice. Clinicians' assessments included symptoms of obstruction, WHO performance status, lung function tests and adverse effects of treatment. Patients completed a Rotterdam Symptom Checklist at all assessments and a daily diary card to record the severity of major symptoms during the first 4 weeks. To show a difference of 15% in the relief of breathlessness rates at 4 months (from 65% to 80%), 400 patients were required. In spite of our many previously successful lung cancer trials, and initial interest from clinicians in 24 UK centres, who estimated they could randomize 200 patients per year into the present trial, only 75 patients were randomized from seven centres over 3.5 years. Intake to the trial was therefore abandoned in November 1996 although an independent Data Monitoring and Ethics Committee had concluded in April 1996 that the scientific case for the trial was still strong; there were no competing trials; there were no design problems; and much had been done to promote the trial. The main reasons given by centres for the slow intake were: lack of referrals of untreated patients; patients being referred specifically for endobronchial treatment; patients having already received XRT; emergency endobronchial relief of obstruction being necessary; and XRT and endobronchial treatment being considered complementary and not as alternatives. The relative advantages and disadvantages of XRT versus endobronchial treatment remain to be determined. The lack of recruitment to this trial raises the issue of innovative techniques not being given the chance of proving their worth compared with traditional treatments.

The cross-pin retained implant supported restoration: a study of gasket placement and leakage.

BACKGROUND: Advantages of cross-pin retained implant supported restorations (ISRs) include predictable retrieval and predictable retention. Unlike direct to fixture (DTF) or cement retained restorations, the prosthetic design of a cross-pinned restoration retains gaps at the interfaces between the crown, abutment and cross-pin screw. These spaces permit leakage into the suprastructure and gasket placement has been recommended to prevent this leakage. METHODS: Five different gaskets were assessed for their ability to prevent leakage into a cross-pinned ISR. The gaskets tested were: cement admixture on the cross-pin screw; cement admixture on the inner surface of the coping and the cross-pin screw; cement admixture on the inner surface of the coping only; cement admixture placed 1 mm from the margin of the coping and a filler placed in the abutment chimney. results: Only gaskets which sealed both the cross-pin screw interface and the abutment-crown interface prevented leakage. A filler placed in the abutment chimney prevented leakage into this space but did not prevent fluid accumulating between the coping and abutment. Conservative placement of cement at the margin of the coping failed to prevent leakage. CONCLUSIONS: Cement gaskets may effectively prevent leakage into a cross-pinned ISR. However, the use of a cement as a gasket has to be weighed against the issue of predictable retrieval, cement extrusion and incomplete seating.

Strategies for restoration of single implants and use of cross-pin retained restorations by Australian prosthodontists.

BACKGROUND: Implant supported restorations (ISRs) for the single implant may be cement retained or screw retained. Limited scientific evidence exists to support the superiority of a retention type for either implant or prosthetic success. The aim of this study was to assess preferences of Australian prosthodontists when restoring single implants. In particular, clinical practices for cross-pin retained implant supported restorations for a single implant were investigated. METHODS: A written questionnaire comprised of seven questions, some of which had multiple parts and of both open- and closed-format, was sent to 124 Australian prosthodontists. The questionnaire asked recipients to identify: (1) their preference for retention choice when restoring a single implant; (2) the frequency of use; and (3) clinical practice when restoring a cross-pin retained restoration. RESULTS: Seventy-seven per cent of respondents indicated that direct to fixture (DTF) retention was their first preference. DTF retention was also the most frequently employed restoration for single implants. Respondents indicated that cross-pinned ISRs are employed to maintain retrievability or when DTF is not possible. The majority of respondents indicated they always or sometimes use a gasket with cross-pin retained restorations, though gasket type varied. Thirty-eight respondents (31%) indicated that they would never use a cross-pinned retained restoration for a single ISR. CONCLUSIONS: Australian prosthodontists prefer, and more frequently restore single implants, using DTF retention. Queensland prosthodontists prefer cement retained ISRs. In comparison, cross-pinned restorations tend to be the least favoured and least used retention type. In addition, variation in opinion exists regarding the need for a gasket and type of gasket to be placed.

A national survey of the chemotherapy regimens used to treat small cell lung cancer (SCLC) in the United Kingdom.

Many chemotherapy regimens are used for treating SCLC in the United Kingdom, but it is not known, in any detail, which regimens are used, by which specialists, for which types of patient. We conducted a survey among all medical and clinical oncologists, respiratory physicians and general physicians with respiratory interest in the United Kingdom to find out. The questionnaire asked for the number of SCLC patients treated annually; how many were given chemotherapy; the drugs, doses and schedules chosen according to prognostic group (as defined by the clinician); and the reasons for choice of regimen. 1214 questionnaires were sent out, and responses were received from 1070 (88%) clinicians; 266 (25%) of these treated SCLC with chemotherapy. Of 4674 patients given chemotherapy annually, 36% were given it by clinical oncologists, 30% by medical oncologists, 27% by respiratory physicians, and 7% by general physicians. In all, 34 regimens were reported with 151 different combinations of dose and schedule. In 2311 good prognosis patients, 23 regimens were used, the commonest being ACE (doxorubicin, cyclophosphamide, etoposide), ICbE (ifosfamide, carboplatin, etoposide), CAV (cyclophosphamide, doxorubicin, vincristine), CbE (carboplatin, etoposide), and PE (cisplatin, etoposide). In 1517 poor prognosis patients, 21 regimens were used, the commonest being CAV, EV (etoposide, vincristine), CbE, CAV alternating with PE, and oral etoposide. 452 patients were treated regardless of prognosis and for 219 no prognostic criteria were specified. The remaining 175 were given second-line chemotherapy or were given regimens chosen to avoid toxicity or because of intercurrent disease or other reasons. The main reasons affecting choice of regimen were routine local practice, patients' convenience, quality of life considerations, trial results and cost. The results show wide variation in routine practice and will be useful in reporting and planning clinical trials and in deciding on local treatment policies.

Analysis of messy longitudinal data from a randomized clinical trial. MRC Lung Cancer Working Party.

The randomized clinical trial, LU19, conducted by the Medical Research Council Lung Cancer Working Party, was designed to compare ACE (doxorubicin, cyclophosphamide and etoposide) chemotherapy plus G-CSF (granulocyte colony-stimulating factor) at 2-week intervals versus ACE chemotherapy alone at standard 3-week intervals in patients with small-cell lung cancer. This trial investigated whether more intensive administration of ACE would improve overall survival and affect the quality of life of patients. The report on overall survival and other outcome measures will be published in the Journal of Clinical Oncology. In this paper we focus on methods of analysing aspects of data reflecting quality of life. Twelve symptoms of lung cancer and its treatment - cough, haemoptysis, pain, nausea, vomiting, hoarse voice, sore mouth, rash, lethargy, lack of appetite, alopecia, and dysphagia - were scheduled to be assessed on seven occasions for the ACE arm and on eight occasions for the ACE+G-CSF arm by clinicians during the first 18 weeks of the treatment period. However, in practice the number of assessment forms completed per patient ranged from 1 to 9, and assessment time-points were very different from those planned. These 'messy' longitudinal data are explored by both a summary measure approach, in which experience of a symptom is summarized by a single value, and an extensive model-based statistical approach, which explicitly takes into account correlation within repeated measures. These analyses provide a clear picture of symptom comparisons between the two treatments. The application of various methods offers not only an approach to assessing the robustness of the results but also a basis for investigating reasons for inconsistency of results across methods. We conclude that except lethargy, which is worse in the ACE+G-CSF arm, all symptoms are similar across the two arms during the treatment period.