Accidental Displacement Research Articles

Accidental displacement of gutta-percha to the lingual periosteum: a case report

Debridement and complete obstruction of a root canal system are success criteria of root canal treat- ment. Endodontic failure is usually due to broken instruments, perforations, overfilling, underfilling, and ledges. Root perforation and the accidental displacement of a gutta-percha point from the periosteum to bone is a rare complication in clinical dental practice. The aim of this report is to present a clinical case of accidental displacement of two gutta-perchas to lingual periosteum in the mandibular premo- lar region, along with its surgical treatment. After surgical removal of the gutta-perchas, the patient's clinical symptoms were eliminated. Surgery is the most accepted treatment for accidentally displaced gutta-percha.

Electron Probe Microanalysis of Exogenous Pigmentation of Oral Mucosa Originating from Dental Alloy: Two Case Reports

Pigmentation of the oral mucosa is relatively common and has a wide variety of etiologies. Although most pigmented lesions of the oral mucosa are associated with deposition of melanin and accidental displacement of a dental alloy, accurate differential diagnosis of a pigmented lesion is important, especially in the case of malignant melanoma. We report two cases of oral mucosal pigmentation associated with accidental displacement of a dental alloy in which malignant melanoma was suspected. Excisional biopsy was carried out in these cases with the incision line set at approximately 5 mm from the lesions. Histopathologically, brownish foreign substances were observed in the lamina propria. Metal quantitative analyses of the extracted specimens were carried out by electron probe microanalysis (EPMA). The metal components and the mass concentration revealed that the metals were derived from a dental casting silver alloy in Case 1 and from a gold-silver palladium alloy in Case 2. Although exogenous pigmentation originating from a dental alloy is not rare, differential diagnosis of oral pigmented lesions is sometimes very difficult. In such cases, histopathological examination may be necessary for the diagnosis to exclude melanocytic lesions and EPMA may be effective to identify the causative dental alloy.

Disentangling the visual cues used by a jumping spider to locate its microhabitat.

Many arthropod species have evolved to thrive only on the leaves of a particular species of plant, which they must be capable of finding in order to survive accidental displacement, developmental transitions or the changing of the seasons. A number of studies have tested whether such species select leaves to land or oviposit on based on their color, shape or size. Unfortunately, many studies did not control for correlates of these characters, such as the brightness of different colors, the areas of different shapes, and the level of ambient illumination in the vicinity of different sizes of leaves. In the present study, we tested for leaf color, shape and size preferences in a leaf-dwelling jumping spider (Lyssomanes viridis) with known summer and winter host plants, while controlling for these correlates. First, color preferences were tested outdoors under the natural illumination of their forest habitat. Lyssomanes viridis did not prefer to perch on a green substrate compared with various shades of gray, but did prefer the second darkest shade of gray we presented them with. Of the green and gray substrates, this shade of gray's integrated photon flux (350-700 nm), viewed from below, i.e. the spider's perspective in the arena, was the most similar to that of real leaves. This relationship also held when we weighted the transmitted photon flux by the jumping spiders' green photopigment spectral sensitivity. Spiders did not prefer the star-like leaf shape of their summer host plant, Liquidambar styraciflua, to a green circle of the same area. When given a choice between a L. styraciflua leaf-shaped stimulus that was half the area of an otherwise identical alternative, spiders preferred the larger stimulus. However, placing a neutral density filter over the side of the experimental arena with the smaller stimulus abolished this preference, with spiders then being more likely to choose the side of the arena with the smaller stimulus. In conclusion, L. viridis appears to use ambient illumination and possibly perceived leaf brightness but not leaf shape or color to locate its microhabitat. This calls for a careful re-examination of which visual cues a variety of arthropods are actually attending to when they search for their preferred host species or microhabitat.

Accidental displacement of a dental implant into the submandibular space during explantation

Dental implants are reliable and widely used, but complications such as peri-implantitis occasionally necessitate their removal. Accidents during removal are similar to those that may occur during extraction, including displacement into another structure in the maxillofacial region. We present a rare case of accidental displacement into the submandibular space, which happened during an attempt to remove an implant.

Accidental displacement of impacted maxillarythird molar: A case report

An unusual case of an impacted right maxillary third molar that was accidentally displaced into the maxillary sinus during exodontia was surgically retrieved almost 2 months later is described. The tooth was removed under Local anesthesia, after maxillary sinus exposure through Caldwell-Luc approach. Postoperative recovery was uneventful. A month after the retrieval surgery, the maxillary sinus was fully healed and the patient did not present with any complaint.

Motor Unit TrackingUsing High Density Surface Electromyography (HDsEMG). Automated Correction of Electrode Displacement Errors.

This article is part of the Focus Theme of Methods of Information in Medicine on "Biosignal Interpretation: Ad-vanced Methods for Neural Signals and Images". The study discusses a technique to automatically correct for effects of electrode grid displacement across serial surface EMG measurements with high-density electrode arrays (HDsEMG). The goal is to match motor unit signatures from subsequent measurements and by this, achieve automated motor unit tracking. Test recordings of voluntary muscle contractions using HDsEMG were performed on three healthy individuals. Electrode grid displacements were mimicked in repeated recordings while measuring the exact position of the grid. A concept of accounting for translational and rotational displacements by making the projection of the recorded motor unit action potentials is first introduced. Then, this concept was tested for the performed measurements attempting the automated matching of the similar motor unit action potentials across different trials. The ability to perform automated correction (projection) of the isolated motor unit action potentials was first shown using large angular displacements. Then, for accidental (small) displacements of the recording grid, the ability to automatically track motor units across different measurement trials was shown. It was possible to track 10 -15% of identified motor units. This proof of concept study demonstrates an automated correction allowing the identification of an increased number of same motor unit action potentials across different measurements. By this, great potential is demonstrated for assisting motor unit tracking studies, indicating that otherwise electrode displacements cannot always be precisely described.

The Sihler staining study of the infraorbital nerve and its clinical complication.

The infraorbital nerve (ION) is a cardinal cutaneous nerve that provides general sensation to the mid face. Its twigs are vulnerable to iatrogenic damage during medical and dental manipulations. The aims of this study were to elucidate the distribution pattern of the ION and thus help to prevent nerve damage during medical procedures and to enable accurate prognostic evaluation where complications do occur. This was achieved by treating 7 human hemifaces with the Sihler modified staining protocol, which enables clear visualization of the course and distribution of nerves without the accidental displacement of these structures that can occur during classic dissection. The twigs of the ION can be classified into the usual 5 groups: inferior palpebral, innervating the lower eyelid in a fan-shaped area; external and internal nasal, reaching the nosewing and philtrum including the septal area between the nostrils, respectively; as well as medial and lateral superior labial, supplying the superior labial area from the midline to the mouth corner. Of particular note, the superior labial twigs fully innervated the infraorbital triangle formed by the infraorbital foramen, the most lateral point of the nosewing, and the mouth corner. In the superior 3-quarter area, the ION twigs made anastomoses with the buccal branches of the facial nerve, forming an infraorbital nervous plexus. The infraorbital triangle may be considered a dangerous zone with respect to the risk for iatrogenic complications associated with the various medical interventions such as implant placement.

Zero-Effort Camera-Assisted Calibration Techniques for Wearable Motion Sensors.

Activity recognition using wearable motion sensors plays an important role in pervasive wellness and healthcare monitoring applications. The activity recognition algorithms are often designed to work with a known orientation of sensors on the body. In the case of accidental displacement of the motion sensors, it is important to identify the new sensor location and orientation. This step, often called calibration or recalibration, requires extra effort from the user to either perform a set of known movements, or enter information about the placement of the sensors manually. In this paper, we propose a camera-assisted calibration approach that does not require any extra effort from the user. The calibration is done seamlessly when the user appears in front of the camera (in our case, a Kinect camera) and performs an arbitrary activity of choice (e.g., walking in front of the camera). We provide experimental results supporting the effectiveness of our approach.

Intraoral management of displaced root into submandibular space under local anaesthesia -A case report and review of literature.

Accidental displacement of an impacted third molar, either a root fragment, crown, or the entire tooth, is a rare complication that occurs during exodontia. The most common sites of dislodgment of an impacted mandibular third molar fragment are the sublingual, submandibular, and pterygomandibular spaces. Removal of a displaced root tip from these spaces may be complex due to poor visualization and limited access. A thorough evaluation of all significant risk factors must be performed in advance to prevent complications. This paper reports the case of a patient who presented with a mandibular third molar root that was displaced into submandibular space. The case was managed intraorally under local anaesthesia and review of the literature.

The Story of a Missing Tooth: A Case Report

The displacement of an impacted third molar, either a root fragment, the crown, or the entire tooth is a complication that rarely occurs during exodontia. Although the complication is well known, reported cases in the dental literature are sparse. We report here an unusual accidental displacement of a mandibular third molar crown into the parapharyngeal space in an adult male patient. As a result if a complication does occur during third molar extraction such in our case, dentists should immediately refer the patient to an oral and maxillofacial surgeon and should not try to remove the displaced root without proper assurance. This is imperative for being able to evaluate the condition of the tooth preoperatively, select adequate instruments and technique, and take good care during extraction and prevent the risk of hemorrhage, neurologic injury, and further displacement of the tooth. Localization with images and proper surgical methods are the keys to retrieving the displaced fragment successfully. In combination with clinical examination, conventional and advanced radiographic techniques were utilized in order to locate the crown for retrieval surgery. This report not only describes the location, but also the surgical removal of an accidentally displaced mandibular third molar displaced in the parapharayngeal space, two weeks after first attempt of extraction.

Accidental Displacement of Dental Implants Into Both Maxillary Sinuses During Surgery

Accidental Displacement of Dental Implants Into Both Maxillary Sinuses During Surgery

Disc-retained tubes for radiologically inserted gastrostomy (RIG): Not up to the job?

To assess the insertion procedure and performance of disc-retained gastrostomy tubes, recording complications and accidental displacements by prospective audit, and to determine whether primary placement of the tube off-licence was feasible. Disc-retained 12F single-lumen Monarch gastrostomy tubes (Enteral UK, Selby, UK) were inserted by three gastrointestinal interventional radiologists in a supra-regional cancer centre. The 12F tubes required a 20F peel-away sheath with four-point gastropexy fixation and were placed under conscious sedation, using electrocardiogram (EEG) bispectral index monitoring. Follow-up was performed in an in-house gastrostomy drop-in clinic at 1 week and 1 month, supplemented with weekly telephone follow-up. Patients also had open access to the gastrostomy drop-in clinic for immediate advice and complication management. Eighteen patients underwent primary insertion of a Monarch gastrostomy tube over 5 months. A total of 6/18 (33%) tubes displaced; 4/18 (22%) completely, 2/18 (11%) occult into the peritoneum. Four of 18 (22%) patients developed infection at the stoma site. Due to the unexpectedly poor performance of the tube, the study was terminated early. Initial experience with the Monarch disc-retained gastrostomy tube demonstrates it unsuitable for primary placement with current protocols. In view of the potentially serious complications, the Medicines and Healthcare Products Regulatory Agency (MHRA) has been informed. A request has been made to the distributer to reassess the tube design and/or review the procedure promoted for primary placement.

Removal of a Maxillary Third Molar Displaced into Pterygopalatine Fossa via Intraoral Approach

The removal of impacted maxillary third molars is one of the most common procedures performed in oral and maxillofacial surgery units with low rates of complications and morbidity. A few cases of accidental displacement of third molars into adjacent anatomical spaces, such as the infratemporal fossa, the pterygomandibular space, the maxillary sinus, buccal space, or the lateral pharyngeal space, during surgical interventions have been reported. In this paper, a case of a maxillary third molar accidentally displaced into the pterygopalatine fossa is presented, and the removal of the tooth via intraoral approach is described.

Accidental displacement of third molars; report of three cases, review of literature and treatment recommendations

AbstractThe displaced third molar is a rare but potentially serious complication of extraction. Every dentist should treat it with care, and when the accident occurs, the general dentist should refer the patient to an oral and maxillofacial surgeon as soon as possible. The surgeon should localise the fragment by appropriate imaging and should remove it by a technique suited to the situation. We present our experience with three displaced third molars: one in the maxillary sinus, one in the submandibular space and one in the pterygomandibular space, all of which were all surgically retrieved without any surgical complications. A review of literature on the subject is examined and a treatment guideline is suggested for use when confronted with such accidents.

Endoscopic Removal of a Maxillary Third Molar Displaced Into the Maxillary Sinus via the Socket

Removal of a maxillary third molar is a common dental procedure, and oral surgeons rarely experience accidental displacement of a maxillary impacted third molar into the maxillary sinus as a complication of this procedure. In the case in which such displacement occurs, the molar is removed via a transantral (Caldwell-Luc) approach through bone removal or window osteotomy of the anterior wall of the maxillary sinus. However, this approach is highly invasive because 2 surgical fields are required at the socket and the anterior wall of the maxillary sinus. Here, we report as a minimally invasive approach endoscopic removal of a maxillary third molar displaced into the maxillary sinus via the socket.

PMO-078 Technical feasibility: mechanically-retained low-profile button gastrostomy

IntroductionA replacement button-gastrostomy has been developed, retained by a mechanical internal fixator formed by loops of the tube shaft. When stretched by the introducer/extractor tool it returns to a completely...

Safe method of extraction to prevent a deeply-impacted maxillary third molar being displaced into the maxillary sinus

b In addition, the bur must be gripped by another instrument. As a safer method for removing deeply-impacted maxillary third molars, we extract them with the repositioning pin that emoval of impacted maxillary third molars is a common peration, usually for orthodontic indications. Displacement f the molar into the maxillary sinus or infratemporal fossa s a rare complication.1,2 However, there is the possibility f accidental displacement when the third molar is deeply mpacted, particularly if its roots are not developed and it lies long the maxillary sinus, or if its roots are developed but it s close to or in the maxillary sinus. We report a safe method f extraction to prevent its displacement into the maxillary inus. After a gingival flap has been raised and the crown of he deeply-impacted maxillary third molar exposed, we drill he crown with a small diamond bur. A repositioning pin s inserted into the handle of a miniscrewdriver (KLS Marin, Tuttlingen, Germany) (Fig. 1) that is used to reduce the ondylar fragment,3 and inserted clockwise into the drilling ole (Fig. 2). Because the pin is fixed tightly by this tapping, he tooth can be removed safely using an elevator and the pin ithout the risk of displacement (Figs. 3 and 4). Excessive force while using the elevator can cause dislacement of the tooth. Experienced and less experienced urgeons alike may encounter such a complication when emoving deeply-impacted maxillary third molars, and thereore a safe method of removal is necessary. Papadogeorgakis 4 t al. reported extraction by rotating a round bur wedged in he crown after drilling 5–7 mm deep into the dentino-enamel unction. However, the bur may loosen with this method

CT fluoroscopy-guided percutaneous gastrostomy with loop gastropexy and peel-away sheath trocar technique in 31 amyotrophic lateral sclerosis patients

In amyotrophic lateral sclerosis (ALS) patients with respiratory impairment and/or advanced disease, performing even mild sedation - as is usually necessary for percutaneous endoscopic gastrostomy (PEG) placements - is fraught with risk. These patients are often referred to Interventional Radiology for alternative percutaneous gastrostomy tube placement options. To report our experience with CT fluoroscopy-guided percutaneous gastrostomy with a novel loop gastropexy and peel-away sheath trocar technique in ALS patients as an alternative to endoscopic techniques. A consecutive series of 31 amyotrophic lateral sclerosis patients in whom endoscopic gastrostomy was considered too dangerous or impossible to perform underwent CT-guided percutaneous gastropexy and gastrostomy and prospective follow-up. All procedures were performed with a 15 FR Freka® Pexact gastrostomy kit, a 16-row CT scanner (Aquilion 16) and single shot CT fluoroscopy mode. The procedure was performed successfully in 30 of 31 patients (20 men, 11 women; median age 60 years, range 38-80 years). In the remaining case the stomach was punctured under CT fluoroscopy and CO2 insufflation was initiated thereafter, leading to successful gastrostomy without prior gastropexy and without further adverse events during follow-up. Two patients reported unproblematic exchange of a balloon tube due to skin irritations with no further adverse events. One patient reported accidental displacement of an exchanged new balloon tube in domestic environment due to balloon leakage: A new balloon tube was easily re-inserted in a hospital the same day. No serious adverse events such as peritonitis, persistent local bleeding, systemic blood loss, or any local infection requiring surgical intervention were observed. Until August 11, 2011 follow-up resulted in 7473 cumulative gastrostomy-days from the date of first placement. Initial results suggest that the described technique under CT guidance is feasible and safe and may especially be advantageous in cases where endoscopic gastrostomy and sedation are contraindicated.

Graphite flake self-retraction response based on potential seeking

The high elastic modulus and interlayer strengths of graphite flakes make them a durable solid superlubricant. Apart from this, they have configurable electrical properties, exhibit quantum Hall effects, and possess a myriad of useful photonic properties. The self-retraction behavior of graphite flakes can have significant impact on the creation of ordered stacks for various applications because any accidental or intentional displacement of the top flake over the stacks below may result in a misalignment of the carbon-carbon atomic arrangement which, in turn, can have influence over the electrical and photonic properties. It has also been revealed that there was a tendency of the displaced microflake to fail at times to return to its original starting position and orientation. Here, we elucidate this behavior by considering the influence of the interlayer potential forces based on minimal potential energy seeking. The maps of the parameters interrogated here provide the ability for precautions to be undertaken. They also potentially permit the creation of an array of microflake stacks in which the metastable states permit different information to be encoded by virtue of the differentiated photonic or electrical characteristics readable from each array site.

Iatrogenic Displacement of Lower Third Molar Roots Into the Sublingual Space: Report of 6 Cases

To describe the clinical characteristics of patients who have had sublingual displacement of a mandibular third molar root, to identify potential risk factors, and to provide the clinician with information on how to prevent and treat this complication. A retrospective analysis was performed of a series of 6 patients who underwent third molar removal with accidental displacement of a root into the sublingual space. All patients were attended at the Department of Oral Surgery, Faculty of Dentistry, University of Barcelona (Spain) from 2000 through 2010. Four patients were men, and the mean age was 38.2 ± 11.3 years. In 1 case, the fragment was removed immediately after the complication, in the same surgical procedure. In 4 cases (66.7%), the displaced root remained asymptomatic (mean follow-up, 25.5 mo), and only 1 patient presented symptoms (swelling and pain in the sublingual region). A second surgical procedure using an intraoral approach was used to extract the displaced fragment in 2 patients. These 2 cases presented transitory nerve impairment of the lingual and inferior alveolar nerves, respectively. Accidental displacement of a lower third molar root into the sublingual space is an uncommon complication. When the fragments are small, surgical removal of the displaced roots seems to be unnecessary, because patients usually remain symptom free. When surgery is needed, a considerable incidence of complications should be expected.