ABSTRACT
PURPOSE: The authors have been using improved superelastic Nickel-Titanium alloy wire (ISW) to close and align extraction spaces simultaneously, instead of separately using rigid wires for closing extraction spaces and Ni-Ti alloy wires for leveling and aligning. ISW has a low stiffness, which makes it challenging to generate sufficient moments. This study aimed to demonstrate the forces and moments exerted on adjacent brackets using an orthodontic simulator (OSIM) attached to a high-precision 6-axis sensor. MATERIALS AND METHODS: In experiment 1, a 0.016 × 0.022-inch ISW, stainless steel (SS) wire, and ß-titanium wires were ligatured into the two brackets. The 0.018 × 0.025-inch slot self-ligating brackets were bonded to two simulated teeth at the same height, and the experiment was conducted using the high-precision OSIM. The distance between the brackets was 10 mm, the V-bend angles of the installed wires were 10°, 20°, 30°, and 40°, and the apex position was set at the center of the bracket. In experiment 2, 6.0- and 9.0-mm long elastomeric chains were placed on the same brackets as in Experiment 1 to measure forces and moments. The distance between the brackets was increased by 1.0 mm from 6.0 to 15.0 mm. Both experiments were conducted in a 37 °C thermostatic chamber similar to the oral environment. RESULTS AND DISCUSSION: In experiment 1, we measured moments on both sides for all the wires. As the V-bend angle increased, the absolute values of the moments also increased. With a V-bend angle of 10°, there was a significant (p < 0.05) difference in the moment generated in the left and right brackets among the three wire types. In the ISW, -1.67 ± 0.38 Nã»mm was generated in the left bracket, while 0.38 ± 0.26 Nã»mm was generated in the right bracket at 10°. At 20°, -1.77 ± 0.69 Nã»mm was generated in the left bracket, while 2.37 ± 0.94 Nã»mm was generated in the right bracket. At 30°, -2.98 ± 0.49 Nã»mm was generated in the left bracket, while 3.25 ± 0.32 Nã»mm was generated in the right bracket. Moreover, at 40°, -3.96 ± 0.58 Nã»mm was generated in the left bracket, while 3.55 ± 0.53 Nã»mm was generated in the right bracket. Furthermore, in experiment 2, the moments increased in proportion to the increase in distance between the centers of the two brackets. Absolute values of the moments were approximately equal for the left and right brackets. The 6.0-mm elastomeric chain generated a minimum force of -0.09 ± 0.05 N in the left direction when the distance between brackets was 6.0 mm, while a maximum of 1.24 ± 0.3 N when the distance between brackets was 12 mm in the right bracket. In the left bracket, minimum and maximum forces of -0.09 ± 0.07 and 1.3 ± 0.4 N were generated in the right direction, respectively. The 9.0-mm elastomeric chain generated a minimum force of 0.03 ± 0.07 N in the left direction when the distance between brackets was 9.0 mm, while a maximum of 1.3 ± 0.1 N when the distance between brackets was 15 mm in the right bracket. In the left bracket, minimum and maximum forces of 0.05 ± 0.06 and 0.98 ± 0.2 N were generated in the right direction, respectively. CONCLUSION: Mechanical data of the ISW have been collected in the study, which was previously difficult to perform owing to the low stiffness of the wire. It is suggested that the ISW can provide sufficient moments with the addition of V-bends to close the space by bodily movement.
Subject(s)
Alloys , Orthodontic Brackets , Titanium , Orthodontic Wires , Torque , Stainless Steel , Dental Stress Analysis , Materials Testing , Dental AlloysSubject(s)
Antineoplastic Agents , COVID-19 , Febrile Neutropenia , Neoplasms , Humans , Pandemics , Granulocyte Colony-Stimulating Factor/therapeutic use , Neoplasms/therapy , Neoplasms/drug therapy , Febrile Neutropenia/drug therapy , Emergency Service, Hospital , Granulocytes , Antineoplastic Agents/adverse effectsABSTRACT
OBJECTIVES: Elderly acute ischemic stroke (AIS) patients (≥80 years) would have dismal clinical outcomes even after successful endovascular revascularization for large vessel occlusion (LVO) in the anterior circulation. We aimed to identify predictors of 30-day mortality after endovascular thrombectomy (EVT) in the elderly. MATERIALS AND METHODS: We included older patients who underwent EVT for AIS due to LVO within 6â h after stroke onset in the anterior circulation between 2017 and 2019. Patients due to posterior circulation stroke, with intracerebral hemorrhage (ICH) or pre-stroke modified Rankin Scale (mRS) score of 4 and 5 were excluded. The primary outcome was mortality within 30 days of EVT. The association between clinical, imaging, procedural, follow-up imaging and mortality were analyzed. Successful reperfusion was defined as modified Thrombolysis in Cerebral Infarction (mTICI) score of 2b or 3. Possible predictors of 30-day mortality were assessed by univariate and multivariable logistic regression. RESULTS: Total 238 AIS patients eligible for EVT were identified with 58 patients aged 80 years or more. 48 patients met inclusion criteria. Median age was 86 years (age range, 82-102 years). Successful reperfusion was achieved in 38 (79.2%) patients. The 30-day and 90-day mortality rate were 25% and 33.3%, respectively. The independent predictors of 30-day mortality were collateral scores <3 on mCTA (adjusted OR, 16.571; 95% CI, 1.041-263.868; p = 0.047) and number of passes (adjusted OR, 2.475; 95% CI, 1.047-5.847; p = 0.039). CONCLUSIONS: Lower collateral scores on mCTA and higher number of passes in thrombectomy were independently predictive of 30-day mortality in the elderly.
Subject(s)
Brain Ischemia , Endovascular Procedures , Ischemic Stroke , Stroke , Aged , Humans , Aged, 80 and over , Retrospective Studies , Treatment Outcome , Endovascular Procedures/methods , Stroke/surgery , Thrombectomy/methodsABSTRACT
BACKGROUND: The incidence of stroke in young patients (20-50 years old) has increased in recent decades. Unlike the use of good functional outcomes to evaluate prognosis, excellent functional outcomes are a better indicator of return to work among younger patients. The rate of return to work increases with time after stroke. This study investigated the short term (3 months) and long term (1 year) predictors of excellent functional outcomes in young patients after endovascular thrombectomy (EVT). METHODS: We included young patients who underwent EVT for acute ischemic stroke (AIS) due to large vessel occlusion within 6 hours after stroke onset between 2015 and 2021. Patients with intracerebral hemorrhage on pretreatment CT were excluded. The associations between clinical, imaging, and procedure variables, and excellent functional outcomes were analyzed using univariate and multivariable logistic regression analyses. An excellent functional outcome was defined as a modified Rankin Scale score of ≤1. RESULTS: Of the 361 patients with AIS eligible for EVT, 55 young patients (aged 24-50 years) were included. Of these, 36.4% and 41.8% achieved excellent functional outcomes at 3 and 12 months, respectively. Multivariate analysis revealed that smoking was the independent negative predictor of both 3 month (adjusted OR (aOR) 0.232, 95% CI 0.058 to 0.928; p=0.039) and 12 month (aOR 0.180, 95% CI 0.044 to 0.741; p=0.018) excellent functional outcomes. CONCLUSIONS: Current or former smoking habit was an independent negative predictor of both short term and long term excellent functional outcomes in young adults with AIS.
ABSTRACT
OBJECTIVE: Restorative treatment of anterior teeth is often required as the final step of orthodontic therapy to optimize the esthetics and function. This case report presents a direct minimally invasive approach for post-orthodontic recontouring of anterior teeth using the composite injection technique with a digital workflow. CLINICAL CONSIDERATIONS: The extraction of central incisors with short roots was indicated to resolve maxillary anterior crowding. The gained space was closed with lateral incisors, and it was necessary to recontour them and canines to resemble central and lateral incisors, respectively. The restorations were digitally designed, and a transparent silicone index was fabricated from a 3D-printed cast of the digital wax-up. After lateral incisors and canines were bonded with a universal adhesive in the etch-and-rinse mode, a highly filled injectable composite resin was applied into the index. The restorative treatment was preceded by gingivectomy using an Er:YAG laser and home bleaching. CONCLUSIONS: In cases where more complex recontouring of anterior teeth is necessary, the composite injection technique could be a suitable alternative to indirect restorations, because it is straightforward, cost-effective, and does not require any preparation. The digital workflow simplified and expedited the treatment while contributing to its precision. CLINICAL SIGNIFICANCE: Post-orthodontic recontouring using direct composite restorations is well accepted by patients due to low cost and non-invasiveness. However, in complicated cases, the free-hand technique is time-consuming and technique-sensitive. The presented composite injection technique with a digital workflow significantly simplifies and expedites the composite placement while predictably enhancing the treatment outcome.
Subject(s)
Dental Restoration, Permanent , Workflow , Composite Resins , Esthetics, Dental , Humans , IncisorABSTRACT
The purpose of this study is to develop the sensing device which measures three-axis force and three-axis moment for reducing the number of accident in orthodontic treatment. The device is necessary for adequate quantitative evaluation of orthodontic forces during orthodontics. The developed sensing device is composed of six-axis force sensors, tooth models, and arms for connecting sensors and tooth models. The developed device simulates rows of teeth in orthodontic operation and measures $14 \times 6$ axes force and moment from tooth models simultaneously. The averages of the difference of force and moment to theoretical values in each direction are 1.78 % (0.043 N) and 2.72 % (0.60 Nmm) respectively. The average moment applying couple forces is 17.1 % (0.81 Nmm). Then the device is able to measure more accurately as the value of the moment was larger. Therefore using our proposed device, we can conduct the orthodontic treatment which dentition moves large for attaching the rail of wire to the teeth.
Subject(s)
Tooth , Accidents , Biomechanical Phenomena , Models, Dental , Orthodontic Appliance Design , Orthodontic Wires , Stress, MechanicalABSTRACT
BACKGROUND Vascular anomalies of the carotid vessels can be attributed to false embryogenesis. A rare variant called a nonbifurcating carotid artery (NBCA) exists, where typical carotid bifurcation is not recognizable with its typical branches of the external carotid artery (ECA) and internal carotid artery (ICA). This paper describes a case of this anomaly and reviews the embryogenesis of the carotid arteries for explanation. CASE REPORT A 66-year-old man received a routine health examination at our hospital. Initial carotid ultrasound indicated an absence of bifurcation in the right cervical carotid artery, and magnetic resonance imaging of the brain indicated an absence of the proximal cervical segment of the right ICA, with a remnant arterial stump at the expected bifurcation level. No evidence of the carotid bulb was identified. The common carotid artery seemed to continue cranially in the trunk of the ECA, where it exhibited extracranial branches. After distributing these branches, the carotid artery coursed medially at the C2 level, where it ascended into the carotid canal to become the petrosal segment of the ICA. This carotid anomaly was labelled an NBCA. No aberrant intracranial arteries were derived from the NBCA in this case. CONCLUSIONS In this case, the arterial stump was considered a remnant from agenesis of the right ICA. We assumed that the NBCA most likely developed because of false regression of the third embryogenic aortic arch with persistence of the second aortic arch.
Subject(s)
Carotid Arteries/abnormalities , Carotid Arteries/embryology , Aged , Brain/blood supply , Carotid Arteries/diagnostic imaging , Carotid Artery, External/abnormalities , Carotid Artery, External/diagnostic imaging , Carotid Artery, External/embryology , Carotid Artery, Internal/abnormalities , Carotid Artery, Internal/diagnostic imaging , Carotid Artery, Internal/embryology , Humans , Magnetic Resonance Imaging , MaleABSTRACT
BACKGROUND/PURPOSE: The application of an appropriate force system is indispensable for successful orthodontic treatments. Second-order moment control is especially important in many clinical situations, so we developed a new force system composed of a straight orthodontic wire and two crimpable hooks of different lengths to produce the second-order moment. The objective of this study was to evaluate this new force system and determine an optimum condition that could be used in clinics. METHODS: We built a premolar extraction model with two teeth according to the concept of a modified orthodontic simulator. This system was activated by applying contractile force from two hooks that generated second-order moment and force. The experimental device incorporated two sensors, and forces and moments were measured along six axes. We changed the contractile force and hook length to elucidate their effects. Three types of commercial wires were tested. RESULTS: The second-order moment was greater on the longer hook side of the model. Vertical force balanced the difference in moments between the two teeth. Greater contractile force generated a greater second-order moment, which reached a limit of 150 g. Excessive contractile force induced more undesired reactions in the other direction. Longer hooks induced greater moment generation, reaching their limit at 10 mm in length. CONCLUSION: The system acted similar to an off-center V-bend and can be applied in clinical practice as an unconventional loop design. We suggest that this force system has the potential for second-order moment control in clinical applications.
Subject(s)
Orthodontic Brackets , Orthodontic Space Closure/methods , Orthodontic Wires , Tooth Movement Techniques/instrumentation , Bicuspid/surgery , Biomechanical Phenomena , Dental Stress Analysis , Humans , Stress, MechanicalABSTRACT
We developed a device to evaluate the orthodontic force applied by systems requiring high operability. A life-sized, two-tooth model was designed, and the measurements were performed using a custom-made jointed attachment, referred to as an "action stick", to allow clearance for the oversized six-axis sensors. This tooth-sensor apparatus was accurately calibrated, and the error was limited. Vector analysis and rotating coordinate transformation were required to derive the force and moment at the tooth from the sensor readings. The device was then used to obtain measurements of the force and moment generated by the V-bend system. Our device was effective, providing results that were consistent with those of previous studies. This measurement device can be manufactured with force sensors of any size, and it can also be expanded to models with any number of teeth.
Subject(s)
Models, Dental , Tooth Movement Techniques , Biomechanical Phenomena , Orthodontic Wires , ToothABSTRACT
BACKGROUND: The purpose of this study was to evaluate the prostate cancer yield rate of targeted transrectal ultrasound (TRUS)-guided biopsy with cognitive magnetic resonance imaging (MRI) registration without concurrent systematic biopsy in patients with previous negative systematic TRUS-guided biopsy results and persistently elevated prostate-specific antigen (PSA) levels. METHODS: In this prospective study conducted from August 2013 to January 2015, patients with at least one previous negative systematic TRUS-guided biopsy and persistently high PSA (≥4 ng/mL) levels were referred for multiparametric MRI (mpMRI). Those patients with suspicious findings on mpMRI received a subsequent cognitive MRI-TRUS fusion biopsy. The cancer-detection rate, tumor location, and Gleason score were confirmed, and PSA-related data were compared between cancer-yield and noncancer-yield groups. RESULTS: In total, 48 patients were included in this study. MRI was designated to be four and five in 17 patients. Fifteen patients received a cognitive fusion-targeted biopsy, and prostate cancers were detected in 10 patients. The cancer-detection rate was 20.8% (10/48), and the positive-predictive value of MRI was 66.7%. No significant differences were observed in the PSA level, PSA velocity, or transitional zone volume between the cancer-yield and noncancer-yield groups; however, the corresponding difference in PSA transitional zone density was significant (p=0.025). CONCLUSION: Cognitive MRI-TRUS fusion-targeted biopsy without concurrent systematic biopsy can detect significant prostate cancer in patients with previous negative systematic biopsy results and persistently elevated PSA levels. Noncancer-yield patients should undergo active surveillance and further follow-ups.
Subject(s)
Image-Guided Biopsy/methods , Magnetic Resonance Imaging/methods , Prostate/pathology , Prostatic Neoplasms/pathology , Aged , Humans , Male , Middle Aged , Prospective Studies , Prostate-Specific Antigen/blood , Prostatic Neoplasms/classification , Ultrasonography, InterventionalABSTRACT
The major issue in selecting patients for transarterial chemoembolization (TACE) lies in determining the optimal number of TACE sessions that may benefit patients before switching to other therapies. This is often a subjective decision not based on any standardized protocol. The ART (Assessment for Retreatment with Transarterial chemoembolization) score was recently developed to determine patients who may benefit from multiple sessions of TACE for treatment of hepatocellular carcinoma. The primary aim of the study was to validate the ART score in a Taiwanese cohort. The secondary aims were to evaluate overall survival and clinical determinants of improved survival in patients treated with multiple TACE sessions. The ART score, clinical characteristics, and outcomes of 82 patients with hepatocellular carcinoma who received multiple TACE sessions at Taipei Veterans General Hospital from September 2007 to July 2013 were analyzed. Among the 82 patients evaluated, 69.5% (n = 57) had an ART score of 0 to 1.5 and 34.1% (n = 25) had a score of ≥2.5. The median overall survival was 23.1 months and the overall mortality rate was 62.2% (n = 51). The ART score was not associated with survival (P = 0.58). Multivariate Cox regression analysis revealed that tumor size >7.2 cm (hazard ratio 4.44, P < 0.001), aspartate transaminase (AST) level above 95âIU/L (hazard ratio 2.18, P = 0.02), AST increase more than 25% (hazard ratio 2.13, P = 0.02), 2nd/1st (pre-TACE) alpha-fetoprotein ratio (hazard ratio 1.40, P = 0.001), and lack of radiological response to TACE (hazard ratio 2.21, P = 0.02) were independent clinical determinants of survival. The ART score was not found to be effective in selecting patients for TACE retreatment in our Taiwanese cohort. Large tumor size, high AST level, high 2nd/1st (pre-TACE) alpha-fetoprotein ratio, AST increase >25%, and lack of radiological response to TACE were independently associated with shorter survival after TACE therapy.
Subject(s)
Carcinoma, Hepatocellular/therapy , Chemoembolization, Therapeutic/methods , Liver Neoplasms/therapy , Adult , Aged , Carcinoma, Hepatocellular/mortality , Carcinoma, Hepatocellular/pathology , Cohort Studies , Female , Humans , Liver Neoplasms/mortality , Liver Neoplasms/pathology , Male , Middle Aged , Patient Selection , Retreatment , Retrospective Studies , Survival Analysis , Taiwan , Treatment OutcomeABSTRACT
BACKGROUND: Percutaneous cryoablation is a minimally invasive alternative for surgical resection of a renal tumor. We report our experience with applying computed tomography-guided cryoablation in renal tumors, focusing on the technique, safety, and treatment response. METHODS: We retrospectively reviewed the medical records of patients who received cryoablation from October 2009 to August 2013 for renal tumor diagnosed by imaging studies performed at Taipei Veterans General Hospital, Taipei, Taiwan. Patient comorbidities and tumor morphology, technical success rate, tumor control rate, renal function change, and complications were recorded. RESULTS: A total of 30 patients (32 tumors) were treated, comprising 30 renal cell carcinomas and two angiomyolipomas. The mean age of the patients was 73.7 years (range, 34-89 years). The patients were referred for percutaneous cryoablation arising from old age, medical comorbidities, or preexisting malignancy. The mean follow-up period was 15.2 months (range, from 32 days to 47.4 months). According to the Clavien-Dindo classification, surgical complications included one Grade III, four Grade II, and two Grade I complications. The mean decrease in hemoglobin was 0.77 g/dL (range, from +1.1 g/dL to -3 g/dL). The mean hospital stay after cryoablation was 2.2 days (range, 1-10 days). Incomplete ablation was noted in two patients and local tumor recurrence in two patients. One of them received repeated cryoablation and achieved successful local control. Of the 22 renal cell carcinoma patients with follow-up period > 6 months, 19 patients achieved successful local tumor control (86.4%). The percentage change of glomerular filtration rate before and 3-6 months after the procedure was +1.9%, which was statistically nonsignificant (p = 0.94). CONCLUSION: Computed tomography-guided percutaneous cryoablation is a safe and effective technique for treating renal tumors with excellent renal function preservation.