Introduction: CAD/CAM restorations of deep cavities are the challenges faced by intraoral-scanner (IOS) for accurate 3D data acquisition. This study aimed to evaluate the influence of cavity depth on the accuracy of intraoral digital impressions.

Methods: Three different mesio-occlusal class II inlay cavities on first maxillary molars were designed and 3D-printed with respective proximal box’s height of 1, 2 and 3mm (group 1, 2, 3 respectively), each of which was scanned 10 times using an IOS. The reference scans of inlay cavities were obtained by an industrial scanner. Data were 3D superimposed with reference impression for trueness (n=10) and intergroup superimposed (n=45) for precision. Outcome variables for value of trueness were mean average deviation (mm), minimum/maximum average deviation (mm) and unacceptable/total elements distribution ratio (%), and for value of precision was mean average deviation (mm).

Results: The 1mm-depth group resulted in the best trueness and precision significantly. For the trueness, there were significant differences between 3 groups with each other, the lowest deviation was for group 1 (21μm) statistically, followed by group 2 (24μm), group 3 (26μm). For the precision, group 1 showed the lowest scattered images statistically (mean deviation 4.7μm), then group 2, 3 (6μm and 13.8μm respectively). The deviated areas were located mostly at gingival walls of the cavity.

Conclusion: The deeper the cavity, the less accurate the digital impressions, which may raise clinical concerns. It suggests the cavity elevation with resin composite might optimize the 3D acquisition of IOS to ensure the fitness of CAD-CAM restorations.

Introduction: Several studies have compared the diagnostic value of sputum induction (SI) with flexible fiberoptic bronchoscopy (FOB) in diagnosing pulmonary tuberculosis; however, these investigations yield an inconsistent conclusion. This study aims to evaluate the role of acid-fast bacilli (AFB) testing of SI and bronchoalveolar lavage (BAL) samples in suspected pulmonary tuberculosis cases.

Methods: A prospective study was conducted at the Department of Pulmonary in Cho Ray Hospital (Ho Chi Minh City, Vietnam) between October 2020 and May 2021. The study comprised 60 patients hospitalized with suspected pulmonary tuberculosis who had at least one negative AFB result from spontaneous sputum or gastric lavage. All participants underwent AFB testing of SI and BAL samples on the same day.

Results: Among 60 patients, 25 (41.7%) were diagnosed with pulmonary tuberculosis. Of the patients with pulmonary tuberculosis, 13 had positive AFB results, including four cases with both positive AFB SI and positive AFB BAL results. The sensitivity of AFB SI was significantly lower compared to that of AFB BAL (16% vs. 52%, p = 0.0027). The most common complication associated with the SI method was cough (15%). The proportion of patients able to provide sputum using the SI method was significantly higher than those with spontaneous sputum (p = 0.0499, McNemar test).

Conclusions: SI is a safe and effective method for collecting respiratory specimens, even from patients unable to expectorate spontaneous sputum. FOB should be reserved for suspected cases of pulmonary tuberculosis that are negative for AFB in spontaneous sputum, SI, and gastric lavage.