Three-dimensional finite element analysis of stress and strain distributions in post-and-core treated maxillary central incisors

PURPOSE: To estimate which combination of restorative materials resulted in the most homogeneous stress and strain distributions in post-and-core treated teeth. MATERIALS AND METHODS: Eight experimental finite element models with different material configurations were simulated; both indirect and direct restorations were considered. An arbitrary load of 50 N was applied on the palatal surface of the crown at a 60-degree angle to the tooth's longitudinal axis to simulate tearing function. RESULTS: In all the models, the values of both strain and stress recorded in the middle third of the buccal aspect of the root surface were off the scale. In contrast, the minimum values were noticed at the level of both the apical portion of the post and the root apex. CONCLUSION: The mechanical properties of the crown and core materials influenced both the position of concentration areas and the level of stress and strain along the dentin/cement/post interfaces.     

Starch-induced implant periapical lesion: a case report

This paper reports an implant periapical lesion (IPL) with a previously unreported etiology. The presence of an osteolytic area around the apex and around the middle portion of a stable Straumann hollow-screw implant was found on periapical radiographs 3.5 years after implant placement. Case management involved curettage of the soft tissue surrounding the implant apex as well as resection of the nonosseointegrated portion of the implant. Histopathologic examination revealed a connective fibrous tissue containing a dense chronic inflammatory infiltrate with a foreign-body material. Polarized light microscopy and Fourier transform infrared microspectroscopy identified the foreign-body material as starch particles. Etiology of this IPL was thus related to a foreign-body reaction to starch particles. This exogenous contamination probably originated from starch-coated gloves during the surgical procedure. This case report suggests that IPL may successfully be treated by debridement and implant resection instead of implant removal. Peri-implant apical soft tissue should be systematically submitted for histopathologic examination.     

The orthodontic treatment of TMD patients: EMG effects of a functional appliance

The aim of this work was to test the effects of the Function Generator Bite (FGB) on the masticatory muscles of temporomandibular joint dysfunction (TMD) subjects. Two groups were selected for the study. A group of 20 TMD patients (group F) requiring orthodontic treatment and treated with FGB and a group of 10 healthy subjects (group H) were considered. Both groups were evaluated before the therapy began (TO) and then after 18 months of therapy (T1). An electromyographic analysis of the masseter and temporalis anterior muscles and a clinical evaluation according to the Research Diagnostic Criteria for TMD (RDC/TMD) were performed. A statistical difference between the two groups was observed at TO with respect to the activity index. TMD subjects showed a lower value of the index. Further studies are necessary to fully understand the utility of this EMG index as a diagnostic indicator.     

Can rotatory knee laxity be predicted in isolated anterior cruciate ligament surgery?

Purpose

Despite the overall success of the surgical anterior cruciate ligament (ACL) reconstruction, some patients still present with instability symptoms even after the surgery, mainly due to the presence of associated lesions. At present, the pivot shift test has been reported to be the benchmark to assess rotatory knee laxity. The purpose of this study was to quantitatively evaluate rotatory knee laxity at time-zero in order to determine whether detected post-reconstruction laxity was predictable by its value measured before the reconstruction, which was hypothized to be influenced by the presence of associated lesions.

Methods

Rotatory knee laxity was retrospectively analysed in 42 patients, including two different ACL reconstructions. The maximal anterior displacement and the absolute value of the posterior acceleration reached during the reduction of the tibial lateral compartment were intra-operatively acquired by using a navigation system and identified as discriminating parameters. For each parameter, statistical linear regression analysis (line slope and intercept) was performed between pre- and post-reconstruction values.

Results

No statistically significant influence of the initial posterior acceleration on the post-reconstruction outcome was found (line slope, p > 0.05), although a statistically significant line intercept was indeed identified (p < 0.001). A statistically significant influence on the surgery outcome was instead found for the initial value of the anterior tibial displacement (line slope = 0.39, p = 0.004), meaning that, on average, about 40 % of the post-reconstruction lateral compartment displacement could be explained by the corresponding pre-reconstruction value. Both of these findings highlighted the importance of intra-operative quantification of rotatory knee laxity to identify correct indications for the surgery.

Conclusions

This study provided important implications for the future possibility of defining a quantifying tool able to assess rotatory knee laxity during ACL reconstruction. This could allow detection of additional injuries to secondary restraints by easily performing rotatory knee laxity tests, which in turn could reduce post-surgical recurrence of knee instability.     

Perioperative identifications of non-palpable pulmonary nodules: a narrative review

Early detection of lung cancer is the key to improving treatment and prognosis of this disease, and the advent of advances in computed tomography (CT) imaging and national screening programs have improved the detection rate of very small pulmonary lesions. As such, the management of this sub-centimetric and often sub-solid lesions has become quite challenging for clinicians, especially for choosing the most suitable diagnostic method. In clinical practice, to fulfill this diagnostic yield, transthoracic needle biopsy (TTNB) is often the first choice especially for peripheral nodules. For lesions for which TTNB could present technical difficulties or failed, other diagnostic strategies are needed. In this case, video-assisted thoracic surgery (VATS) is the gold standard to reach the diagnosis of lung nodules suspect of being malignant. Nonetheless it’s often not easy the identification of such lesions during VATS because of their little dimensions, non-firm consistency, deep localization. In literature various marking techniques have been described, in order to improve intraoperative nodules detection and to reduce conversion rate to thoracotomy: CT-guided hookwire positioning, methylene blue staining, intra-operative ultrasound and electromagnetic navigation bronchoscopy are the most used. The scientific evidence on this matter is weak because there are no randomized clinical trials but only case series on single techniques with no comparison on efficacy, so there are no guidelines to refer. From this standing, in this article we conducted a narrative review of the existing literature on the subject, with the aim of outlining a framework as complete as possible. We analyzed strengths and weaknesses of the main techniques reported, so as to allow the clinician to orient himself with greater ease.     

Curative versus palliative treatments for recurrent hepatocellular carcinoma: a multicentric weighted comparison

BackgroundManagement of recurrence after surgery for hepatocellular carcinoma (rHCC) is still a debate. The aim was to compare the Survival after Recurrence (SAR) of curative (surgery or thermoablation) versus palliative (TACE or Sorafenib) treatments for patients with rHCC.MethodsThis is a multicentric Italian study, which collected data between 2007 and 2018 from 16 centers. Selected patients were then divided according to treatment allocation in Curative (CUR) or Palliative (PAL) Group. Inverse Probability Weighting (IPW) was used to weight the groups.Results1,560 patients were evaluated, of which 421 experienced recurrence and were then eligible: 156 in CUR group and 256 in PAL group. Tumor burden and liver function were weighted by IPW, and two pseudo-population were obtained (CUR = 397.5 and PAL = 415.38). SAR rates at 1, 3 and 5 years were respectively 98.3%, 76.7%, 63.8% for CUR and 91.7%, 64.2% and 48.9% for PAL (p = 0.007). Median DFS was 43 months (95%CI = 32-74) for CUR group, while it was 23 months (95%CI = 18-27) for PAL (p = 0.017). Being treated by palliative approach (HR = 1.75; 95%CI = 1.14–2.67; p = 0.01) and having a median size of the recurrent nodule>5 cm (HR = 1.875; 95%CI = 1.22–2.86; p = 0.004) were the only predictors of mortality after recurrence, while time to recurrence was the only protective factor (HR = 0.616; 95%CI = 0.54–0.69; p<0.001).ConclusionCurative approaches may guarantee long-term survival in case of recurrence.     

Cardiovascular magnetic resonance of cardiac tumors and masses

Cardiac masses diagnosis and treatment are a true challenge, although they are infrequently encountered in clinical practice. They encompass a broad set of lesions that include neoplastic (primary and secondary), non-neoplastic masses and pseudomasses. The clinical presentation of cardiac tumors is highly variable and depends on several factors such as size, location, relation with other structures and mobility. The presumptive diagnosis is made based on a preliminary non-invasive diagnostic work-up due to technical difficulties and risks associated with biopsy, which is still the diagnostic gold standard. The findings should always be interpreted in the clinical context to avoid misdiagnosis, particularly in specific conditions (e.g., infective endocarditis or thrombi). The modern multi-modality imaging techniques has a key role not only for the initial assessment and differential diagnosis but also for management and surveillance of the cardiac masses. Cardiovascular magnetic resonance (CMR) allows an optimal non-invasive localization of the lesion, providing multiplanar information on its relation to surrounding structures. Moreover, with the additional feature of tissue characterization, CMR can be highly effective to distinguish pseudomasses from masses, as well as benign from malignant lesions, with further differential diagnosis of the latter. Although histopathological assessment is important to make a definitive diagnosis, CMR plays a key role in the diagnosis of suspected cardiac masses with a great impact on patient management. This literature review aims to provide a comprehensive overview of cardiac masses, from clinical and imaging protocol to pathological findings.