The purpose of this study was to investigate the effect of four kinds of different contact strength on the three-dimensional displacement of an implant-supported fixed bridge using digital laser speckle photography method. An in vitro model of beagle mandible with an implant-supported fixed bridge in its right premolar region was developed. The bridge was Au-Pt metal-ceramic. The contact was recovered to four different tightnesses, named 0, 1, 2, and 3. Different axial concentrated static load was applied to abutments and bridge respectively. The three-dimensional displacement of the implant-supported fixed bridge was measured using digital laser speckle photographic method. The results demonstrated that the influence of contact tightness was mainly on the mesio-distal and buccal lingual parts. When the contact tightness reached number 3, the regularity of displacement distribution was changed. The present study proved that digital laser speckle photography was an effective method of measuring the micro-displacement. One of the criterions of contact recovering decreased the implant displacement effectively without changing the regularity of displacement distribution.
Animals ; Dental Prosthesis, Implant-Supported ; Denture, Partial, Fixed ; Diagnostic Imaging ; methods ; Dogs ; Lasers ; Mandible ; Models, Animal ; Photography

The purpose of this study was to investigate the three-dimensional displacement of the cantilever fixed partial denture (CFPD) under an oblique loading. One Beagle dog was used in this experiment. The CFPD, which used the second premolar and the first molar as abutments and the second molar as pontic, was made in vitro fresh mandible of the Beagle dog, and the digital laser speckle (DLS) technique was employed to measure the three-dimensional displacement of the CFPD under the oblique loading for the first time. We found that when an oblique loading was exerted on the pontic, the displacement of CFPD was the greatest, and the displacement of the abutment near the pontic was smaller than that of the pontic but greater than that of the abutment far from the pontic. We also found that when an oblique loading was exerted on the abutment, the displacement of the directly loaded abutment was greater than that of the other abutment and the pontic. Under the oblique loading, the displacement increased with increasing of load. The experiment demonstrated that it would be advisable for the clinicians to avoid oblique loading, especially the oblique loading of the pontic when using the CPDF. The DLS technique may be one kind of methods for measuring the three-dimensional displacements of the small and irregular objects.
Animals ; Bite Force ; Dental Abutments ; Dental Stress Analysis ; methods ; Denture Design ; Denture, Partial, Fixed ; Dogs ; Imaging, Three-Dimensional ; Lasers ; Male ; Mandible ; Occlusal Adjustment ; Tooth Mobility

Objective:To explore the feasibility, safety and clinical efficacy of ileum augmentation cystoplasty assisted by Da Vinci robot for the treatment of neurogenic bladder.Methods:Retrospective analysis was performed on the data of 12 patients with neurogenic bladder admitted to Zhejiang Provincial People’s Hospital from March 2017 to November 2018, including 11 males and 1 female, with the mean age of 38(12-67). Preoperative symptoms were urinary incontinence, dysuria, decreased bladder capacity, or increased bladder pressure leading to ureteral reflux. All the 12 patients underwent preoperative intermittent catheterization, including 8 patients with spinal cord injury and 4 patients with spinal cord dysplasia. Preoperative serum creatinine(129.58±44.60)μmol/L and total glomerular filtration rate(61.63±18.04)ml/(min·m 2) were observed in 12 patients. Preoperative urodynamic examination showed the safe bladder volume of (95.67±39.10)ml, bladder internal pressure of(63.30±6.02)cmH 2O(1 cmH 2O=0.098 kPa)at the end of filling period, bladder compliance of(10.24±1.14)ml/cmH 2O, residual urine volume of(152.58±80.89)ml, and urine flow rate of(3.88±3.63)ml/s. Bladder contracture was evident on preoperative cystography. Ultrasound examination showed different degree of hydronephrosis and ureter expansion, in all cases, with ureteral reflux grading Ⅰin 2 cases, grade Ⅱ in 4 cases, grade Ⅲ in 4 cases, grade Ⅳ in 2 cases. All the 12 patients underwent robot-assisted ileum augmentation cystoplasty with 5-point puncture. Transverse incision of the bladder wall before full thickness, according to the amount of bladder and quality to decide 30 cm(normal), longitudinal cut back loops and one point after suture fixation in the bladder wall midpoint, fixed point as starting point, in turn, will be blind to the bladder stitching on both sides, the bilateral ureteral placing a single J tube respectively, evaluation of surgical success rate (including intraoperative bleeding, interception of bowel loops are no damage adjacent viscera, ureter openings with and without damage, impermeability, match insufflate whether unobstructed), postoperative complications, anastomotic fistula, intestinal obstruction, abdominal bleeding), urine dynamics test parameters, and patients’ quality of life. Patients were regularly given anticholinergic drugs(2 mg/d) for 6 months after surgery. Results:All the 12 cases in this group were successfully completed without any transfer to open surgery. The operation time was(120.8±12.0)min. Intraoperative blood loss(84.0±23.2)ml. Postoperative intestinal function recovery time(3.3±1.3) d. Postoperative hospital stay(12.1±3.1)d. Postoperative pelvic drainage tube indwelling time (3.8±1.2) d. Catheter and single J tube were removed 2 weeks after operation. Postoperative follow-up averaged 19.4(3-24) months. At 3, 12, 24 months after surgery, the bladder safety volume was rechecked(435.83±33.56), (450.90±31.09), (462.00±33.72)ml, the bladder internal pressure at the end of filling was(18.60±0.92), (15.70±1.42), (12.96±1.34)cmH 2O, the blood creatinine level was(81.43±21.10), (74.34±15.70), (72.90±15.90)μmol/L, and the bladder compliance was(37.94±4.22), (40.40±3.98), (43.42±4.20)ml/cmH 2O and the total glomerular filtration rate(91.52±9.49), (102.18±5.65), (112.41±6.50)ml/(min·m 2) were significantly improved compared with those before surgery( P<0.001). After 24 months of bladder urination training, 1 patient could basically urinate by herself. Three patients were treated with intermittent urinary catheterization supplemented by automatic urination. The remaining 8 patients were completely dependent on urinary catheter for intermittent catheterization. Postoperative complications such as anastomotic fistula, ileus and abdominal bleeding were not found in 12 patients. Conclusions:Ileum bladder enlargement assisted by robot can effectively expand bladder volume, reduce bladder internal pressure, improve bladder compliance, prevent ureteral reflux and protect renal function.