vendex and Foreign-Bodies

Topics: Adult; Dental Implant-Abutment Design; Dental Implantation, Endosseous; Dental Implants, Single-Tooth; Equipment Failure; Foreign Bodies; Friction; Humans; Male; Surface Properties; Torque

Few studies exist for magnetic resonance imaging (MRI) issues and ballistics, and there are no studies addressing movement, heating, and artifacts associated with ballistics at 3-tesla (T). Movement because of magnetic field interactions and radiofrequency (RF)-induced heating of retained bullets may injure nearby critical structures. Artifacts may also interfere with the diagnostic use of MRI.. To investigate these potential hazards of MRI on a sample of bullets and shotgun pellets.. Laboratory investigation, ex vivo.. Thirty-two different bullets and seven different shotgun pellets, commonly encountered in criminal trauma, were assessed relative to 1.5-, 3-, and 7-T magnetic resonance systems. Magnetic field interactions, including translational attraction and torque, were measured. A representative sample of five bullets were then tested for magnetic field interactions, RF-induced heating, and the generation of artifacts at 3-T.. At all static magnetic field strengths, non-steel-containing bullets and pellets exhibited no movement, whereas one steel core bullet and two steel pellets exhibited movement in excess of what might be considered safe for patients in MRI at 1.5-, 3- and 7-Tesla. At 3-T, the maximum temperature increase of five bullets tested was 1.7°C versus background heating of 1.5°C. Of five bullets tested for artifacts, those without a steel core exhibited small signal voids, whereas a single steel core bullet exhibited a very large signal void.. Ballistics made of lead with copper or alloy jackets appear to be safe with respect to MRI-related movement at 1.5-, 3-, and 7-T static magnetic fields, whereas ballistics containing steel may pose a danger if near critical body structures because of strong magnetic field interactions. Temperature increases of selected ballistics during 3-T MRI was not clinically significant, even for the ferromagnetic projectiles. Finally, ballistics containing steel generated larger artifacts when compared with ballistics made of lead with copper and alloy jackets and may impair the diagnostic use of MRI.

Topics: Artifacts; Foreign Bodies; Forensic Ballistics; Humans; Magnetic Resonance Imaging; Torque; Wounds, Gunshot

Nickel-titanium files often separate because of mechanical fatigue. The purpose of this study was to determine safe preparation techniques for separated file removal by using ultrasonics.. Fifty nickel-titanium file fragments were divided into 5 groups. An ultrasonic tip was activated on a file fragment positioned between dentin blocks simulating several canal conditions: Group 1 consisted of the fragment protruding from a pair of straight dentin blocks. For group 2, the fragment was also positioned between 2 straight dentin blocks except one block was positioned 1 mm more apically than the other block, simulating a troughed area that is often created during file removal attempts. For groups 3-5, the fragment was positioned similarly as group 2 but between blocks with 30°, 45°, and 60° curvatures, respectively. The time it took for secondary fracture to occur was recorded, and the data were statistically analyzed.. Fragments with dentin wall supporting on the opposite side of ultrasonic activation site resisted fracture significantly longer than those without it. Fragments in 30° and 45° curved blocks took significantly longer to fracture than the other groups (Fisher protected least significant difference, P < .05).. Secondary fracture of separated files appeared to be reduced when the ultrasonic tip was applied to the inner curvature of the canal.

Topics: Dental Alloys; Dental Pulp Cavity; Dentin; Elasticity; Equipment Design; Equipment Failure; Foreign Bodies; Humans; Nickel; Pliability; Root Canal Preparation; Time Factors; Titanium; Torque; Torsion, Mechanical; Ultrasonics; Vibration

The purpose of this study was to identify the influential factors responsible for clinical instrument separation of reused ProTaper Universal rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland).. Six thousand one hundred fifty-four root canals in 2,654 teeth were prepared using ProTaper Universal files in endodontic clinics. Separation incidence was determined based on the number of treated teeth or canals. Data were collected including the size of fractured instrument, the length and location of a broken segment within the root canal, and the curvature of canal. The chi-square test and independent samples t test were used to determine the statistical significance.. The overall instrument separation incidences were 2.6% according to the number of teeth and 1.1% according to the canal number, respectively. Separation incidences according to the number of teeth or canals were significantly higher (P < .05) in molars than those in premolars or anterior teeth. Because of its largest diameter, F3 file presented the highest separation incidence according to the number of teeth (1.0%) or canals (0.4%); 47.5% instrument separation of mandibular molars and 61.5% instrument separation of maxillary molars happened in the mesiobuccal canals. Moreover, 91.4% fragments were located in the apical third of root canals, and 54.2% instrument separation occurred in severely curved canals. There was a significant difference (P < .05) in the mean fracture length between shaping (2.42 ± 0.73 mm) and finishing files (3.32 ± 0.73 mm).. Separation incidence according to the canal number is more reliable than that according to the number of teeth because of the variable canal number in different teeth. The tooth type, rotary file size, canal location, and anatomy were correlated with the instrument separation of reused ProTaper Universal files.

Topics: Bicuspid; Dental Alloys; Dental Pulp Cavity; Edetic Acid; Equipment Design; Equipment Failure Analysis; Equipment Reuse; Foreign Bodies; Humans; Microscopy, Electron, Scanning; Molar; Nickel; Radiography, Bitewing; Root Canal Irrigants; Root Canal Preparation; Root Canal Therapy; Rotation; Sodium Hypochlorite; Stress, Mechanical; Surface Properties; Titanium; Tooth Apex; Torque

The entanglement of the otological drill with cotton swabs is a common milling fault in ear surgery. To improve operational safety, this paper presents a method for identifying this type of milling fault.. Force and current sensors were installed on a modified otological drill. In accordance with the DC motor model and cutting force model, two features of the milling process were extracted, namely the characteristic curve and the dynamic relationship between the sensor signals. These are complementary features. An adaptive filter was designed to fuse them together and output a curve that was sensitive to milling faults and was stable during normal milling. Based on the filtering data, a rule base is presented for identifying cotton swab entanglement.. Five surgeons were invited to perform an experiment on calvarian bones. The average recognition rate for milling faults was 90%, whereas only 2% of normal millings were identified as milling faults.. The presented method could adapt to the technique of different surgeons and identify milling faults exactly.

Topics: Electromagnetic Fields; Equipment Failure; Equipment Failure Analysis; Feasibility Studies; Foreign Bodies; Humans; Otolaryngology; Otologic Surgical Procedures; Safety; Software; Surgery, Computer-Assisted; Textiles; Torque

Flapless surgery requires penetration of the alveolar mucosa and bone without reflection of mucoperiosteal flaps. Do these techniques force gingival tissue or foreign materials into osteotomies? If so, do such tissues or materials interfere with osseointegration? A proof-of-principle study using a canine model attempted to answer these questions.. Five young adult Hound Labrador mongrel dogs received implants with a moderately roughened surface by anodic oxidation using flapless or conventional one-stage (control) surgery in contralateral jaw quadrants. The implants were placed into the osteotomies, and the international stability quotient (ISQ) was recorded using resonance frequency analysis. These measurements were repeated following a 3-month healing interval when the animals were euthanized, and implants and surrounding tissues were retrieved and processed for histologic analysis.. The implants were stable upon insertion and demonstrated increased stability at 3 months without significant differences between surgical protocols. The histologic evaluation showed high bone-implant contact (flapless surgery: 54.7% +/- 8.4%; control: 52.2% +/- 13.0%; P >0.05) without evidence of gingival tissue or foreign body inclusions. There were no significant differences in marginal bone levels between the surgical protocols. Post-insertion and at 3 months, ISQ values depended on the amount of torque delivered. Immediately post-insertion, for every 1-unit increase in torque value, the ISQ increased by 0.3 (95% confidence interval: 0.1 to 0.4; P = 0.0043). Three months postoperatively, for every one-unit increase in torque the ISQ value decreased 0.2 (95% confidence interval: -0.4 to -0.1; P = 0.0012). The effect of torque on ISQ values was independent of treatment effects and remained significant after adjustment for treatment.. The results suggest that implants placed without flap reflection remain stable and exhibit clinically relevant osseointegration similar to when implants are placed with flapped procedures. Greater torque at implant placement resulted in less implant stability at 3 months.

Topics: Alveolar Process; Animals; Bone Density; Dental Implants; Dogs; Foreign Bodies; Gingiva; Male; Mandible; Models, Animal; Mouth Mucosa; Osseointegration; Osteotomy; Surface Properties; Surgical Flaps; Time Factors; Torque; Wound Healing