Search

Abstract Background Endobronchial ultrasound (EBUS) and cone-beam computed tomography-derived augmented fluoroscopy (CBCT-AF) are utilized for the diagnosis of peripheral pulmonary lesions (PPLs). Combining them with transbronchial cryobiopsy (TBC) can provide sufficient tissue for genetic analysis. However, cryoprobes of different sizes have varying degrees of flexibility, which can affect their ability to access the target bronchus and potentially impact the accuracy. The aim of this study was to compare the diagnostic efficacy of cryoprobes of varying sizes in CBCT-AF and EBUS for the diagnosis of PPLs. Methods Patients who underwent endobronchial ultrasound-guided transbronchial biopsy (EBUS-TBB) and TBC combined with CBCT-AF for PPLs diagnosis between January 2021 and May 2022 were included. Propensity score matching and competing-risks regression were utilized for data analysis. Primary outcome was the diagnostic accuracy of TBC. Results A total of 284 patients underwent TBC, with 172 using a 1.7-mm cryoprobe (1.7 group) and 112 using a 1.1-mm cryoprobe (1.1 group). Finally, we included 99 paired patients following propensity score matching. The diagnostic accuracy of TBC was higher in the 1.1 group (80.8% vs. 69.7%, P = 0.050), with a similar rate of complications. Subgroup analysis also revealed that the 1.1 group had better accuracy when PPLs were located in the upper lobe (85.2% vs. 66.1%, P = 0.020), when PPLs were smaller than 20 mm (78.8% vs. 48.8%, P = 0.008), and when intra-procedural CBCT was needed to be used (79.5% vs. 42.3%, P = 0.001). TBC obtained larger specimens than TBB in both groups. There is still a trend of larger sample size obtained in the 1.7 group, but there is no statistically different between our two study groups (40.8 mm2 vs. 22.0 mm2, P = 0.283). Conclusions The combination of TBC with CBCT-AF and EBUS is effective in diagnosing PPLs, and a thin cryoprobe is preferred when the PPLs located in difficult areas.

Background/purpose: Patients with disabilities usually have difficulties in communication and mobility, and the quality of the dental treatments are often inferior. This study uses the Taiwan National Health Insurance Database to analyze the quality of dental treatment for patients with disabilities who receive intravenous sedation (IVS). Materials and methods: This study selected patients with disabilities who received dental treatment under IVS. Their oral cavity was divided into three major sections: anterior teeth, upper posterior teeth, and lower posterior teeth. Self-matching of the same section was conducted to observe whether operative dental treatment (OD) with or without IVS affected the occurrence of dental retreatment. This study observed the occurrence of refilling and the duration from the end of treatment until retreatment to compare treatment differences with or without IVS. Results: After self-matching, this study found 158 patients who received dental treatment within the same section with and without IVS. During a follow-up period of 17 years, 75.18% of the patients who received OD treatment required refilling, 10.87% required endodontic treatment, and 5.67% required tooth extraction. After OD treatment with IVS, the risks of refilling, endodontic treatment, and tooth extraction were 0.71 (95% CI: 0.58–0.87, P

Background/purpose: Oral exercise is a training method for swallowing dysfunction in older adults. The study investigated the effect of oral exercise on tongue pressure in older adults in Taiwanese community day care centers over a 3-month period. Materials and methods: Participants over age 50 who were able to communicate and participating for the duration of the 12-week period were recruited from five community day care centers. A 15-min weekly group oral exercise activity was conducted. The tongue pressures were measured and multivariable linear regression models were used to assess the effect of oral exercise intervention on the participants’ tongue pressures. Results: A total of 66 older adult participants, among whom the mean age was 78.06 ± 10.74 years. Tongue pressure continued improving during the intervention period, and the mean tongue pressure at the end of the study was 20.63 ± 10.45 kPa, which was significantly higher than the baseline measurement (16.92 ± 10.62 kPa, p

Abstract Background Rapid on‐site cytologic evaluation (ROSE) helps to improve the diagnostic accuracy in endobronchial ultrasound (EBUS) procedures. However, cytologists are seldom available to perform ROSE in many institutions. Recent studies have investigated the application of deep learning in cytologic image analysis. As such, the present study analyzed lung cytologic images obtained by EBUS procedures, and employed deep‐learning methods to distinguish between benign and malignant cells and to semantically segment malignant cells. Methods Ninety‐seven patients who underwent 104 EBUS procedures were enrolled. Four hundred and ninety‐nine lung cytologic images obtained via ROSE, including 425 malignant and 74 benign, and most malignant were lung adenocarcinoma (64.3%). All the images were used to train a residual network model with 101 layers (ResNet101), with suitable hyperparameters selected to classify benign and malignant lung cytologic images. An HRNet model was also employed to mark the area of malignant cells. Automatic patch‐cropping was adopted to facilitate dataset preparation. Results Malignant cells were successfully classified by ResNet101 with 98.8% classification accuracy, 98.8% sensitivity, and 98.8% specificity in patch‐based classification; 95.5% classification accuracy in image‐based classification; and 92.9% classification accuracy in patient‐based classification. Malignant cell area was successfully marked by HRNet with a mean intersection over union of 89.2%. The automatic cropping method enabled the system to complete diagnosis within 1 s. Conclusions This is the first study to combine lung cytologic image deep‐learning classification with semantic segmentation. The model was optimized for high accuracy and the automatic cropping facilitates the clinical application of our model. The success in both lung cytologic images classification and semantic segmentation on our dataset shows a promising result for clinical application in the future.

Bronchoscopic interventions (BIs) and airway management for bronchoscopy are exceptionally high-risk procedures not only for anesthesiologists, pulmonologists, but also for nursing staff because they expose nurses to COVID-19-containing droplets. However, perioperative changes can be made to the anesthetic management for nonintubated BIs to minimize the spread of COVID-19.

Abstract. To determine the feasibility on maintaining oxygenation of high-flow nasal oxygenation (HFNO) with bispectral index-guided intravenous anesthesia for nonintubated interventional bronchoscopy (NIIB). If desaturation happens, the factors influencing intraprocedural desaturation were also analyzed. This is a single-center retrospective study on patients receiving NIIB with HFNO and intravenous anesthesia guided by bispectral index levels to the depth of general anesthesia, which were between 40 and 60. Intraprocedural desaturation (SPO2

Background/Purpose: Rapid on-site cytologic evaluation (ROSE) has been shown to improve the diagnostic accuracy of endobronchial ultrasound-guided transbronchial biopsy (EBUS-TBB). However, ROSE by a cytopathologist or cytotechnologist is not always available during the procedure. The purposes of this study were to verify that a pulmonologist, after receiving training in cytology, could accurately assess an EBUS-TBB specimen on-site, and to evaluate the contribution of ROSE to EBUS-TBB. Methods: A retrospective chart review of patients who underwent EBUS-TBB for diagnosis of peripheral pulmonary lesions (PPLs) from January 2014 to June 2017 was performed. PPLs without a malignant diagnosis were excluded. The ROSE result determined by a pulmonologist was compared to the formal imprint cytologic report and pathologic report. The diagnostic accuracy of EBUS-TBB was also compared between those with and without ROSE. Results: Two hundred ninety-three patients who underwent 336 EBUS-TBB procedures for PPL diagnosis and were found to have proven malignancy were enrolled. Eighty-six procedures were performed with ROSE. With the formal imprint cytologic diagnosis as the standard, ROSE had 96.9% sensitivity, 68.2% specificity, 89.9% positive predictive value (PPV), 88.2% negative predictive value (NPV), and 89.5% diagnostic accuracy. With the formal pathologic result as the standard, ROSE had 88.2% sensitivity, 80% specificity, 97.1% PPV, 47.1% NPV, and 87.2% diagnostic accuracy, respectively. The diagnostic accuracy was significantly higher when ROSE was performed during EBUS-TBB (88.4% vs 68.0%, P

Abstract This study compared effects of plasma-activated medium (PAM) with effects of conventional clinical thermal therapy on both lung cancer cells and benign cells for management of malignant pleural effusion (MPE). For MPE treatment, chemotherapy, photodynamic therapy, and thermal therapy are used but caused systemic side effects, patient photosensitivity, and edema, respectively. Recent studies show that plasma induces apoptosis in cancer cells with minor effects on normal cells and is cost-effective. However, the effects of plasma on MPE have not been investigated previously. This study applied a nonthermal atmospheric-pressure plasma jet to treat RPMI medium to produce PAM, carefully controlled the long-life reactive oxygen and nitrogen species concentration in PAM, and treated the cells. The influence of PAM treatment on the microenvironment of cells was also checked. The results indicated that PAM selectively inhibited CL1–5 and A549 cells, exerting minor effects on benign mesothelial and fibroblast cells. In contrast to selective lethal effects of PAM, thermal therapy inhibited both CL1–5 and benign mesothelial cells. This study also found that fibroblast growth factor 1 is not the factor explaining why PAM can selectively inhibit CL1–5 cells. These results indicate that PAM is potentially a less-harmful and cost-effective adjuvant therapy for MPE.

BackgroundMicroorganisms of tuberculosis (TB) are frequently difficult to identify from the airway specimen; therefore, lung biopsy for further histologic and microbiologic study is required. Endobronchial ultrasound-guided transbronchial biopsy (EBUS-TBB) is used for the diagnosis of pulmonary malignancy, but is rarely in the TB population. The purpose of this study was to verify the effectiveness and safety of EBUS-TBB with histologic study and tissue culture in the diagnosis of sputum smear-negative pulmonary TB.MethodsPatients who underwent EBUS-TBB with histologic study and TB tissue culture for clinically suspected, but sputum smear-negative pulmonary TB from January 2016 to December 2018, were included. The accuracy of each diagnostic modality was calculated, respectively. Factors that might influence the positive rate of TB culture (washing fluid and tissue specimen) were also evaluated.ResultsOne hundred sixty-one patients who underwent EBUS-TBB for clinically suspected, but sputum smear-negative pulmonary TB, were enrolled, and 43 of them were finally diagnosed as having pulmonary TB. The sensitivity of washing fluid (a combination of smear, culture, and polymerase chain reaction for TB) and tissue specimen (a combination of pathology and tissue culture) via EBUS-TBB for TB diagnosis were 48.8 and 55.8%, respectively. The sensitivity for TB diagnosis would be elevated to 67.4% when both washing fluid and tissue specimens are used. The positive TB culture rate would not statistically increase with a combination of tissue specimens and washing fluid. Univariate analysis revealed that TB microorganisms would be more easily cultivated when lesions had an abscess or cavity on the computed tomography (CT) image (presence vs. absence; 62.5 vs. 26.3%, p = 0.022), heterogeneous echogenicity on the EBUS finding (heterogeneous vs. homogeneous; 93.3 vs. 21.4%, p = 0.001), or a necrotic pattern via histologic study (presence vs. absence; 70.6 vs. 30.8%, p = 0.013). Heterogeneous echogenicity in the EBUS finding was the independent predictor according to the results of multivariate analysis. None of our patients encountered major adverse events or received further intensive care after EBUS-TBB.ConclusionEndobronchial ultrasound-guided transbronchial biopsy is safe and effective for use in diagnosing sputum smear-negative pulmonary TB. EBUS echoic feature is also a predictor of the positive TB culture rate in pulmonary TB. However, tissue culture via EBUS-TBB has little effect in improving the positive TB culture rate.

Endobronchial ultrasound (EBUS)-guided transbronchial biopsy (TBB) is a common procedure used to diagnose peripheral pulmonary lesions (PPLs). However, existing literature did not conclusively show a difference in the ability of EBUS-TBB with and without a guide sheath (GS) to diagnose PPLs. This multicenter cohort study enrolled patients presenting for EBUS-TBB of PPLs that finally proved to be malignant. The diagnostic yield and complication rate were compared between patients undergoing EBUS-TBB with and without a GS (EBUS-TBB+GS versus EBUS-TBB−GS). A propensity score matching method was used to balance differences of pertinent clinical features between the two groups. The original cohort consisted of 975 patients (556 in EBUS-TBB−GS; 419 in EBUS-TBB+GS). GS guidance was more likely to be used with smaller (40 mm versus 44 mm) and middle or lower lobe (60% versus 35%) lesions. After propensity score matching, 720 (360 in each group) patients were included; the diagnostic yields for PPLs were 79% and 78% for EBUS-TBB−GS and EBUS-TBB+GS groups, respectively (p=0.649). The complication rates (5.8% versus 7.2% for bleeding; 0.6% versus 1.9% for pneumothorax) appeared to be lower in the EBUS-TBB+GS group, but the differences did not reach statistical significance. The procedure time was significantly longer in the EBUS-TBB+GS group than in the EBUS-TBB−GS group (29 min versus 24 min; p

Background/Purpose: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has been gradually introduced in the diagnosis of mediastinal tuberculous (TB) lymphadenitis. The purposes of this study were to evaluate the utility of polymerase chain reaction for Mycobacterium tuberculosis (TB-PCR) using EBUS-TBNA rinse fluid and to explore the factors that influence the accuracy of EBUS-TBNA. Methods: A retrospective study with prospective data collection was carried out with patients with unselected mediastinal lymphadenopathy who underwent EBUS-TBNA and a TB-PCR study from April 2010 to July 2017. Patients without TB were excluded. The diagnostic accuracy rate for each diagnostic modality (pathology, smear, culture, and TB-PCR) was calculated respectively. The characteristics of the lymph node (LN) and the pathologic findings were analyzed as possible impact factors. Results: 240 consecutive patients who received EBUS-TBNA were enrolled, and in the end, 21 patients with a diagnosis of TB lymphadenitis were included. When combined with histologic results and traditional microbiologic studies, the diagnostic accuracy of EBUS-TBNA was 57.1%. If TB-PCR was also utilized, the diagnostic accuracy would significantly increase to 71.4% (p

Summary: Background/Objective: Virtual assisted lung mapping (VAL-MAP) is a bronchoscopic lung marking technique developed to assist in navigational lung resection. It can be used for nodule localization and segmental identification. This article presents our initial experience of thoracoscopic pulmonary segmentectomy using combined VAL-MAP and computed tomography (CT)-guided localization. Material and methods: Markings with India Ink were made bronchoscopically, before surgery, using a virtual bronchoscopy system (LungPoint® Planner) without fluoroscopy guidance. Post VAL-MAP CT scans localized the actual markings. All data on patients, markings, and outcomes were retrospectively collected, and the contribution of VAL-MAP to the operation was graded by the surgeon. Results: From March 2017 to September 2017, 24 consecutive patients received the VAL-MAP marking procedure before thoracoscopic segmentectomy. Nineteen patients also received pre-operative CT-guided percutaneous localization after VAL-MAP; fifteen patients received CT-guided localization with dye (patent blue V) and microcoil, and four patients received with dye only. Of the 101 marking attempts made in all the patients, 71 (70.3%) were identified as contributing to the surgery. No clinically evident complications were associated with the procedure. A total of 24 segmentectomies were thoracoscopically conducted for 18 cases of lung cancer and six cases of benign diseases. Conclusion: The combination of VAL-MAP and CT-guided percutaneous localization contribute to precise thoracoscopic pulmonary segmentectomy. Keywords: VAL-MAP, CT-Guided localization, Segmentectomy, Lung cancer

Abstract Primary pulmonary lymphoma is an uncommon disease, and extranodal marginal zone lymphoma of mucosa‐associated lymphoid tissue (MALT) is the most common type of pulmonary lymphoma. The most frequent pattern observed in chest computed tomography (CT) is consolidation, followed by nodules and mass. The differentiation of pulmonary MALT lymphoma from other lung diseases is critical for disease management and treatment. However, pulmonary MALT lymphoma with isolated endobronchial manifestation has seldomly been reported. Here, we report a case of an elderly woman who presented with a four‐month history of cough, dyspnoea, and haemoptysis. Chest CT scan revealed left main bronchus narrowing without lung parenchymal lesion. Bronchoscopic examination was performed, and the diagnosis of primary pulmonary MALT lymphoma with isolated endobronchial involvement was made. She has been successfully treated with rituximab.

This study evaluated the performance of the Xpert MTB/RIF Ultra assay (Xpert Ultra) to detect smear-negative pulmonary tuberculosis (PTB). Xpert Ultra assay was prospectively performed using bronchial washing fluid (BWF) in comparison to COBAS TaqMan MTB (COBAS) assay and mycobacterial culture. Of the 165 enrolled participants, 27 (16.4%) had PTB based on composite reference standard and 16 (9.7%) had culture-confirmed PTB. By the composite reference standard of PTB, the sensitivity of Xpert Ultra (63.0, 95% confidence interval, CI, 42.4–80.6%) was higher than the COBAS assay (25.9%, P = 0.006), BWF-culture (33.3%, P = 0.029) and sputum-culture (37.0%, P = 0.057). Meanwhile, the specificity of Xpert Ultra was 99.3% which was slightly lower than the 100.0% specificity of the COBAS assay (P = 1.000) and cultures (P = 1.000). Against the reference standard of culture-confirmed PTB, Xpert Ultra also had a higher sensitivity (62.5, 95% CI, 35.4–84.8%) than the COBAS assay (31.3%, P = 0.077) and was similar to BWF-culture (56.3%, P = 0.719) and sputum-culture (62.5%, P = 1.000). However, one subject with previously treated old PTB had a false-positive result on the Xpert Ultra assay. This prospective study showed Xpert Ultra assay using BWF had better sensitivity than COBAS assay and mycobacterial cultures but could represent a false positive in patients with inactive old PTB.

Background/Purpose: Endobronchial ultrasound (EBUS) elastography is a new technique that provides information on tissue compressibility during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). The purposes of this study were to evaluate the utility of EBUS elastography in differentiating malignant and benign mediastinal lymph nodes (LNs) and to explore the factors that influence its accuracy. Methods: A retrospective chart review of patients who underwent EBUS-TBNA from October 2016 to July 2017 was performed. EBUS with conventional B-mode features and elastographic patterns were compared with the final pathology results or clinical follow-up. We used the following EBUS elastographic patterns for classification: type 1, predominantly non-blue (green, yellow and red); type 2, part blue, part non-blue; type 3, predominantly blue. The potential impacts of the characteristics of LNs, the underlying lung diseases and obtaining fibrotic components from EBUS-TBNA specimens were evaluated relative to the accuracy of EBUS elastography. Results: A total of 206 LNs from 94 patients were retrospectively evaluated. In classifying type 1 as ‘benign’ and type 3 as ‘malignant,’ the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy rate were 90.6, 82.6, 71.6, 94.7 and 85.2%, respectively. The EBUS elastographic patterns had higher diagnostic yields and negative predictive values than conventional B-mode features. Logistic regression analysis revealed that central necrosis was a factor that influenced the accuracy of elastography in malignant LNs. The fibrotic component within benign LNs could cause an incorrect elastographic pattern. Conclusion: EBUS elastography is a valuable tool in discriminating benign and malignant mediastinal LNs. Keywords: Elastography, Endobronchial ultrasound-guided transbronchial needle, Mediastinal lymph node

Background: Endobronchial ultrasound-guided transbronchial biopsy (EBUS-TBB) is used for the diagnosis of peripheral pulmonary lesions (PPLs), but the diagnostic yield is not adequate. Cone-beam computed tomography-derived augmented fluoroscopy (CBCT-AF) can be utilized to assess the location of PPLs and biopsy devices, and has the potential to improve the diagnostic accuracy of bronchoscopic techniques. The purpose of this study was to verify the contribution of CBCT-AF to EBUS-TBB. Methods: Patients who underwent EBUS-TBB for diagnosis of PPLs were enrolled. The navigation success rate and diagnostic yield were used to evaluate the effectiveness of CBCT-AF in EBUS-TBB. Results: In this study, 236 patients who underwent EBUS-TBB for PPL diagnosis were enrolled. One hundred fifteen patients were in CBCT-AF group and 121 were in non-AF group. The navigation success rate was significantly higher in the CBCT-AF group (96.5% vs. 86.8%, p = 0.006). The diagnostic yield was even better in the CBCT-AF group when the target lesion was small in size (68.8% vs. 0%, p = 0.026 for lesions ≤10 mm and 77.5% vs. 46.4%, p = 0.016 for lesions 10–20 mm, respectively). The diagnostic yield of the two study groups became similar when the procedures with a failure of navigation were excluded. The procedure-related complication rate was similar between the two study groups. Conclusion: CBCT-AF is safe, and effectively enhances the navigation success rate, thereby increasing the diagnostic yield of EBUS-TBB for PPLs.

In this paper, we demonstrate an innovative electromagnetic targeting system utilizing a passive magnetic-flux-concentrator for tracking endobronchoscope used in the diagnosis process of lung cancer tumors/lesions. The system consists of a magnetic-flux emitting coil, a magnetic-flux receiving electromagnets-array, and high permeability silicon-steel sheets rolled as a collar (as the passive magnetic-flux-concentrator) fixed in a guide sheath of an endobronchoscope. The emitting coil is used to produce AC magnetic-flux, which is consequently received by the receiving electromagnets-array. Due to the electromagnetic-induction, a voltage is induced in the receiving electromagnets-array. When the endobronchoscope’s guide sheath (with the silicon-steel collar) travels between the emitting coil and the receiving electromagnets-arrays, the magnetic flux is concentrated by the silicon-steel collar and thereby the induced voltage is changed. Through analyzing the voltage−pattern change, the location of the silicon−steel collar with the guide sheath is targeted. For testing, a bronchial-tree model for training medical doctors and operators is used to test our system. According to experimental results, the system is successfully verified to be able to target the endobronchoscope in the bronchial-tree model. The targeting errors on the x-, y- and z-axes are 9 mm, 10 mm, and 5 mm, respectively.

This two-part study aimed to investigate compliance with the sepsis resuscitation bundle (SRB) and the barriers to its implementation for patients developing septic shock in the general medical wards. Methods: In the first part, medical records of patients who were admitted to the intensive care unit from the general medical wards due to septic shock were reviewed. Compliance rates with the six SRB components were assessed. In the second part, responsible junior physicians (first-year and second-year residents) in the general wards and senior physicians (third-year residents and fellows) were randomly invited for questionnaire-based interviews. Results: In the first part, during the 6-month study period, 40 patients were included. Overall compliance with the SRB within 6 h was only 2.5%, mainly due to femoral catheterization (42.5%) and the lack of measuring central venous oxygen saturation (ScvO2). Delayed completion of SRB components contributed little to the low compliance rate. In the second part, based on the questionnaire results of 71 junior physicians and 64 senior physicians, the junior physicians were less familiar with the SRB guidelines, particularly regarding the meaning of ScvO2 (p = 0.01) and management of low ScvO2 (p = 0.04). Junior physicians were also more reluctant to measure the central venous pressure (CVP; p = 0.04) and the ScvO2 (p = 0.01), and were also less confident with internal jugular vein or subclavian vein catheterization (p

Byline: Ching-Chi Lin (1,2), Ching-Kai Lin (1), Kun-Ming Wu (1), Chon-Shin Chou (1) Keywords: Obstructive sleep apnea syndrome; Cardiopulmonary exercise test; Nasal CPAP; VO2peak; Anaerobic threshold; Oxygen pulse Abstract: This study was done to evaluate whether cardiac dysfunction or abnormal measurements on cardiopulmonary exercise testing (CPET) can be improved after 2 months of nasal CPAP treatment. Twenty patients with moderate or severe OSAS received nasal CPAP treatment. All subjects also underwent blood pressure, simple spirometric, and arterial blood gas (ABG) measurements cardiac evaluation by radionuclide scanning and CPET and an overnight polysomnography sleep study before and after nasal CPAP treatment. No difference in left ventricular ejection fraction (LVEF) was found after 2 months of nasal CPAP treatment, but higher right ventricular ejection fraction (RVEF), VO2peak, VO2peak/kg and workpeak were observed. After 2 months of nasal CPAP treatment, these patients had a lower breathing reserve and a greater increase in anaerobic threshold and oxygen pulse. Moderate to severe OSAS patients before nasal CPAP treatment had abnormal CPET as reflected by lower RVEF, VO2peak/kg, workpeak, anaerobic threshold and oxygen pulse. These abnormalities can be improved after 2 months of nasal CPAP treatment. Author Affiliation: (1) Chest Division, Department of Internal Medicine, Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan (2) Mackay Junior College of Nursing, Taipei, Taiwan Article History: Registration Date: 01/01/2004

Purpose: To determine the cement bond strength and marginal leakage of castings cemented to implant abutments. Materials and Methods: Fifty-six titanium abutments and castings were divided into 7 groups (n = 8), 1 for each cement. Castings were cemented to abutments using 1 of 3 resin-based cements (RES, RES-B, and RES-B-P), a resin-modified glass ionomer (GI), a polycarboxylate cement (PCB), an acrylic urethane cement (UDM), or a zinc phosphate cement (ZP). Specimens were placed in 100% humidity at 37°C for 24 hours. Specimens were subjected to compressive load cycling followed by thermal cycling; they were then immersed for 24 hours in 0.5% basic fuchsin. Castings were removed with an Instron universal testing machine with a crosshead speed of 0.125 cm/min. Leakage was visually graded from 0 (no leakage) to 2 (leakage extended beyond the lower half of the internal surface of the casting). Failure load (FL) was analyzed with analysis of variance and Scheffe's test (α = .05). Chi-square was used to analyze leakage (α = .05). Results: Cements were categorized by FL into 4 statistically unique groups: (1) RES-B-P (351 N) and GI (337 N); (2) ZP (245 N) and RES-B (241 N); (3) PCB (107 N); and (4) RES (63 N) and UDM (55 N). Leakage was greater for the PCB group than for the other groups (7 of 8 specimens demonstrated leakage; P < .01). Three ZP specimens demonstrated leakage. UDM and RES each had 1 specimen with leakage. RES-B-P, RES-B, and GI showed no leakage. Conclusions: Luting agents designated by the manufacturer as provisional cements demonstrated lower resistance to removal, regardless of material type. Luting agents described by manufacturers as "permanent" differed in resistance, with resin cements being most resistant, followed by zinc phosphate and polycarboxylate cements. Provisional cements demonstrated leakage comparable to higher-strength materials. [ABSTRACT FROM AUTHOR]