Injection of n-Butyl-2-Cyanoacrylate into the Abdominal Aortic Aneurysm Sac during Endovascular Aortic Repair to Prevent Type II Endoleaks Caused by Lumbar Arteries.

PURPOSE: To evaluate midterm results of whether the strategy to occlude target lumbar arteries using n-butyl-2-cyanoacrylate (nBCA) injection during endovascular aneurysm repair (EVAR) reduced the incidence of Type II endoleak (T2EL) after EVAR. MATERIALS AND METHODS: Between 2013 and 2020, 187 patients underwent EVAR; 106 in the treatment group received nBCA injection during EVAR, whereas 81 in the historical control group did not. The incidence of T2EL at 7 days, need for reintervention, and post-EVAR aneurysmal shrinkage were compared between the groups. RESULTS: Between the treatment group and the control group, significant differences were achieved in the incidence of T2EL (2.8% vs 28.4%; P < .0001) and decreased aneurysmal diameter was observed at 1 year after EVAR (-5.2 vs -3.8 mm; P = .034). In multivariate analysis, nBCA injection (odds ratio [OR], 0.04; P = .001) and younger age (OR, 0.92; P = .036) were significantly associated with a reduced incidence of T2EL. As a possible adverse event associated with nBCA injection, 2 cases of transient lower-limb motor dysfunction (1.9%) were observed. Propensity score analysis revealed that the treatment group had a significantly lower incidence of T2EL than that in the control group (P = .0002) even though there was no difference in the incidence of inferior mesenteric artery coil embolization between the groups. The survival rate without aneurysm sac enlargement (100.0% vs 69.8%; P = .014) and the reintervention-free rate (100.0% vs 63.1%; P = .034) in the treatment group were significantly higher than those in the control group. CONCLUSIONS: Concomitant nBCA injection can provide durable EVAR without T2EL, as supported by the avoidance of reintervention associated with aneurysm sac enlargement.

Pre-endodontic Post and Core Technique for Endodontic and Prosthodontic Treatment.

INTRODUCTION: Displacement of provisional fixed prostheses may result in undesirable and embarrassing outcomes in dental treatments, especially in endodontic treatment. Development of certain counter measures has been necessary to avoid such discomforts. AIM: The aim of this report was to propose a pre-endodontic post and core technique to achieve smooth progress of the treatment. MATERIALS AND METHODS: The patient was a 59-year-old male diagnosed with an infraocclusion caused by wear of his teeth. He received full mouth provisional fixed restorations for a complete oral rehabilitation. Displacement and fracture of the restorations frequently occurred during the observation period for the function of the restorations. Therefore, the pre-endodontic post and core technique was applied to the abutment teeth before their endodontic treatments were started. The technique consisted of three steps as follows: Step 1: Caries removal and dowel preparation were performed for the abutment teeth having apical periodontitis. Composite cores were indirectly fabricated, which had access holes for endodontic treatment. Step 2: The cores were bonded to the teeth. In endodontic treatment, rubber dam appliances were easily placed owing to the core, and proper tooth isolation was accomplished. Step 3: Fiberposts were bonded to the dowel holes through the access holes after the root canal filling. During endodontic treatment, displacement and/or fracture of the provisional restorations did not occur. CONCLUSION: The pre-endodontic post and core technique was effective in obtaining improved retention of provisional restoration, appropriate isolation for endodontic treatment, and sufficient retention of the post and core. CLINICAL SIGNIFICANCE: The pre-endodontic post and core technique is useful for avoiding the discomforts in dental treatments, namely, a smooth transition from endodontic to prosthodontic treatment can be achieved.

Designing anterior cantilever resin-bonded fixed dental prostheses based on finite element analysis.

PURPOSE: A resin-bonded bridge (RBB) is a minimally invasive prosthetic treatment option for intact adjacent teeth. However, it is contentious as to whether the mesial or distal adjacent tooth should be used as an abutment. This study aimed to investigate the potential of finite element analysis (FEA) for the selection of abutment teeth and the determination of the optimal design for anterior cantilever RBBs. METHODS: Three types of RBBs were designed to simulate loss of the maxillary left lateral incisor. The fixed-fixed RBB (FF-RBB) had one retainer each for the left central incisor and canine. Distal- and mesial-cantilever RBBs (D-CRBB and M-CRBB) had a single retainer on the central incisor and canine, respectively. Three-dimensional models for FEA were generated from computed tomography slices and dental casts. FEA was performed for each RBB to evaluate stresses in the intercuspal, protrusive, and lateral mandibular positions. RESULTS: The maximum principal stresses on the bridges in the intercuspal position were 141.9 MPa, 93.6 MPa, and 45.7 MPa, for the FF-RBB, D-CRBB, and M-CRBB, respectively. The stress in the D-CRBB position was greater than in the M-CRBB position in the intercuspal, protrusive, and lateral mandibular positions. CONCLUSIONS: Based on the results, M-CRBB on the canine had a higher clinical performance than D-CRBB on the central incisor. FEA was useful for determining the optimal design of RBB for each patient.

Orthodontic Management of the Edentulous Space Caused by Surgical Removal of a Large Dentigerous Cyst.

Herein, we report the orthodontic management of a patient with excessive bone and permanent tooth loss after surgical cyst removal. The patient was a 13-year-old Japanese boy who was referred to our department by an oral surgeon. He had an edentulous space with alveolar bone loss and loss of 2 permanent molars in the left mandibular region, following surgical removal of a large dentigerous cyst. We decided to close this space orthodontically. First, we moved the left mandibular second premolar into the edentulous region and autotransplanted the left maxillary lateral incisor in the adjacent distal space. We then performed comprehensive orthodontic treatment to establish stable occlusion. Following treatment, functional and stable occlusion of all permanent teeth was achieved without any spaces. The findings from this case suggest that orthodontic treatment is effective in growing patients with edentulous spaces and alveolar bone loss.

Considerations for the selection of interim restoration materials using wear test results.

PURPOSE: The purpose of this study was to examine the wear of resin materials using two-body wear tests and to verify a selection method for optimal interim restoration materials from findings of a diagnostic occlusal device. METHODS: Specimens were prepared from nine different resins used for diagnostic occlusal devices (soft resin) and interim restorations. Wear tests were conducted using an abrasion testing machine. The resulting wear on resin specimens and antagonist stainless-steel styluses was measured using a laser confocal scanning microscope, and the surface conditions were observed through a scanning electron microscope. The data were analyzed with one-way ANOVA and Tukey's multiple comparison test. The findings of the previous study on diagnostic occlusal devices were referred to in order to verify the selection method of optimal interim restoration materials. RESULTS: The maximum wear depth of the soft resin specimens was significantly greater than that of the other specimens (p<0.05) and was equivalent to the wear depth of a diagnostic occlusal device used for 14 nights. The wear of bis-acryl resin material was shallower than that of the other materials (Polymethyl methacrylate and polyethyl methacrylate), and its antagonist stylus was significantly worn (p<0.05). CONCLUSION: The findings of the previous and present studies showed a relationship among the parameters of Electromyography, wear depth of the diagnostic occlusal device, and wear of materials used for interim restorations. Findings related to bruxism can guide in the selection of interim restoration material and the determination of a suitable duration of wear.

Crystalline complex of syndiotactic polystyrene with poly(ethylene glycol) dimethyl ethers.

It has been clarified that syndiotactic polystyrene (sPS) forms co-crystalline structures with polyethylene glycol dimethyl ethers (PEGDMEs) with molecular weights ranging from 178 to 1,000 g·mol(-1) through a guest exchange procedure assisted by a plasticizing agent. The PEGDME molecules are incorporated into the spaces between sPS polymer sheets consisting of (T(2)G(2))(2) helices. The results of X-ray diffraction and gravimetric measurements suggest that one or less molecules are included per unit cell for PEGDME with average molecular weight of 1,000 g·mol(-1), which indicates the possibility that longer polymeric molecules can be introduced into sPS lattices with multiple site occupation.

Automatic segmentation of teeth from dentomaxillofacial 3D-CT images.

CT is an effective tool for image diagnosis because it enables noninvasive observation of internal organs. In the course of CT, 3D-CT, such as a helical scanning CT and a multi-detector row CT, has been developed. With the use of 3D-CT, organs can be observed from several viewing directions. Even now, however, 3D-CT images are generated by manual procedures to extract objective organs using the threshold method. These procedures waste time and effort. Therefore, development of highly automated and effective extracting techniques has been desired. The region growing (RG) method is one of the effective techniques of extracting internal organs. The conventional RG method, however, has some defects. Extracted regions are strongly affected by the threshold value for segmentation. A break point on a region contour yields a leakage of region. To overcome these defects, we formulated a modified region growing method with edge detection (MRGWED) which combines a three-dimensional region growing technique and an edge detection technique. Using the MRGWED, we tried to extract teeth from dentomaxillofacial 3D-CT image data.

Effect of fatigue loading on the screw joint stability of zirconium abutment.

PURPOSE: This study evaluated the effect of fatigue loading on the screw joint stability of a zirconium abutment connected to an external hexagon implant in vitro. MATERIALS AND METHODS: Fifteen titanium and 15 zirconia abutments of 3 different heights (5, 8, and 11 mm) were connected to external titanium implants with titanium screws. A torque gauge was used to measure the reverse torque values before and after loading. An air cylindrical loading device was used to simulate mastication at a 45-degree angle to the longitudinal axis of the implant. RESULTS: There were significant differences (P<0.05) before and after the loading of titanium (5mm) and zirconia (5, 8, and 11 mm) abutments. CONCLUSION: Zirconia abutments for external hexagon implants had durability rates similar to those of titanium abutments after repeating load on the reverse torque of the abutment screw, indicating that the zirconia abutment could be reliably used instead of the titanium abutment.