The two-shot technique is an effective stopping power method. The precise mechanisms of action on the bone and soft-tissue structures of the skull; however, remain largely unclear. The aim of this study is to compare the terminal ballistics of the two-shot and single-shot techniques.
Materials and Methods:
40 fresh pigs’ heads were randomly divided into 4 groups (n = 10). Either a single shot or two shots were fired at each head with a full metal jacket or a semi-jacketed bullet. Using thin-layer computed tomography and photography, the diameter of the destruction pattern and the fractures along the bullet path were then imaged and assessed.
A single shot fired with a full metal jacket bullet causes minor lateral destruction along the bullet path. With two shots fired with a full metal jacket bullet, however, the maximum diameter of the bullet path is significantly greater (P < 0.05) than it is with a single shot fired with a full metal jacket bullet. In contrast, the maximum diameter with a semi-jacketed bullet is similar with the single-shot and two-shot techniques.
With the two-shot technique, a full metal jacket bullet causes a destruction pattern that is comparable to that of a single shot fired with a semi-jacketed bullet.
Ballistics; full metal jacket; two-shot technique
Aim was to compare clinical findings with x-ray findings using dental panoramic radiography (DPR). In addition, type and frequency of secondary findings in x-rays were investigated.
Patients were selected on the basis of available DPRs (not older than 12 months). No therapeutic measures were permitted between the DPR and the clinical findings. The clinical findings were carried out by several investigators who had no knowledge of the purpose of the study. A calibrated investigator established the x-ray findings, independently and without prior knowledge of the clinical findings. The evaluation parameters for each tooth were: missing, healthy, carious, restorative or prosthetically sufficient or insufficient treatment. Type and frequency of additional findings in the DPR were documented, e.g. quality of a root canal filling and apical changes.
Findings of 275 patients were available. Comparison showed a correspondence between clinical and radiographic finding in 93.6% of all teeth (n = 7,789). The differences were not significant (p > 0.05). Regarding carious as well as insufficiently restored or prosthetically treated teeth, respectively there were significant differences between the two methods (p < 0.05). The DPRs showed additional findings: root fillings in 259 teeth and 145 teeth with periapical changes.
With reference to the assessment of teeth, there was no difference between the two methods. However, in the evaluation of carious as well as teeth with insufficiently restorative or prosthetic treatment, there was a clear discrepancy between the two methods. Therefore, it would have been possible to have dispensed with x-rays. Nevertheless, additional x-ray findings were found.
Dental findings; Radiographic findings; Dental panoramic radiography (DPR); Clinical examination
To compare two methods of creating three-dimensional representations of mandibular cysts and tumors on the basis of computed tomography (CT) and cone beam computed tomography (CBCT) data.
A total of 71 patients with acquired jaw cysts took part in this retrospective clinical study. CT and CBCT scans were obtained from all patients and saved in the Digital Imaging and Communications in Medicine (DICOM) format. Data were analyzed twice with iPlan software. Analysis was performed manually and using an interpolarization algorithm. The accuracy of the two methods in assessing cyst volume was compared.
Manual delineation did not provide more accurate results than the interpolarization algorithm.
There are no major differences between manual analysis and analysis using the interpolarization algorithm. The use of the algorithm, however, has the advantage of rapidity.
Odontogenic lesion; Segmentation; Cyst volume; iPlan
Changes in ambient pressure occur during flying, diving, or hyperbaric oxygen therapy and can cause different types of pathophysiological conditions and pain including toothache (barodontalgia). We report the case of a patient with severe pain in the region of his mandibular left first molar, which had been satisfactorily restored with a conservative restoration. Pain occurred during an airplane flight and persisted after landing. Radiology revealed a periapical radiolucency in the region of the distal root apex. Pain relief was achieved only after endodontic treatment. On the basis of this paper, we investigated the aetiology and management of barodontalgia. Dentists should advise patients to avoid exposure to pressure changes until all necessary surgical, conservative, and prosthetic procedures have been completed. The influence of pressure divergences should be noted at any time. Under changed environment pressures may be the changing perception of pathologies.
Aim. To measure and validate the permeability of pressure changes in correlation to different root filling techniques. Methods. Eighty extracted single-rooted teeth were randomly assigned to one of eight groups of ten teeth. Following standardized instrumentation and irrigation, root canal fillings were performed using either cold lateral condensation, a warm carrier-based gutta-percha obturation technique, a warm carrier-based Resilon, or warm gutta-percha compaction with the downpack/backfill technique. After insertion of a pressure sensor within the pulp chamber ten teeth of each group then underwent simulated dives with pressure measurement and the other ten a dye penetration test during simulated dives to 5.0 bar. Differences were analyzed statistically (P < 0.05) using one-way analysis of variance (ANOVA). Results. When the warm carrier-based gutta-percha obturation technique and vertical gutta-percha obturation techniques were used, there was significant lower intrapulpal pressure to experimental chamber pressure (P > 0.05). When cold lateral condensation or carrier-based Resilon as used, pressure was sometimes almost completely equalized. Conclusions. Warm gutta-percha obturation techniques provide a largely pressure-tight seal whereas the Resilon obturation technique and cold lateral condensation appear to be unsuitable to pressure changes.
The zygoma plays an important role in the facial contour for both cosmetic and functional reasons; therefore zygomatic bone injuries should be properly diagnosed and adequately treated. Comparison of various surgical approaches and their complications can only be done objectively using outcome measurements which in turn require protocol management and long-term follow up. The preference for open reduction and internal fixation of zygomatic fractures at three points has continued to grow in response to observations of inadequate results from two point and one point fixation techniques.
The objectives of this study were to compare the efficacy of zygomatic bone after treatment with ORIF using 2 point fixation and ORIF using 3 point fixation and compare the outcome of two procedures.
100 patients were randomly divided equally into two groups. In group A, 50 patients were treated by ORIF using two point fixation by miniplates and in group B, 50 patients were treated by ORIF using three point fixation by miniplates. They were evaluated for their complications during and after surgery with their advantages and disadvantages and the difference between the two groups was observed.
A total of 100 fractures were sustained. We found that postoperative complication like decreased malar height and vertical dystopia was more common in those patients who were treated by two point fixation than those who were treated with three point fixation.
Based on this study open reduction and internal fixation using three point fixation by miniplates is the best available method for the treatment zygomatic bone fractures.
Zygomatic fracture; Open reduction; Internal fixation; Three point fixation; Two point fixation
Modern high-velocity projectiles produce temporary cavities and can thus cause extensive tissue destruction along the bullet path. It is still unclear whether gelatin blocks, which are used as a well-accepted tissue simulant, allow the effects of projectiles to be adequately investigated and how these effects are influenced by caliber size.
Barium titanate particles were distributed throughout a test chamber for an assessment of wound contamination. We fired .22-caliber Magnum bullets first into gelatin blocks and then into porcine hind limbs placed behind the chamber. Two other types of bullets (.222-caliber bullets and 6.5 × 57 mm cartridges) were then shot into porcine hind limbs. Permanent and temporary wound cavities as well as the spatial distribution of barium titanate particles in relation to the bullet path were evaluated radiologically.
A comparison of the gelatin blocks and hind limbs showed significant differences (p < 0.05) in the mean results for all parameters. There were significant differences between the bullets of different calibers in the depth to which barium titanate particles penetrated the porcine hind limbs. Almost no particles, however, were found at a penetration depth of 10 cm or more. By contrast, gas cavities were detected along the entire bullet path.
Gelatin is only of limited value for evaluating the path of high-velocity projectiles and the contamination of wounds by exogenous particles. There is a direct relationship between the presence of gas cavities in the tissue along the bullet path and caliber size. These cavities, however, are only mildly contaminated by exogenous particles.
Forensic science; Wound infection; Gunshot; Projectile; Gelatin
It is widely known that stress conditioning can protect microcirculation and induce the release of vasoactive factors for a period of several hours. Little, however, is known about the long-term effects of stress conditioning on microcirculation, especially on the microcirculation of the periosteum of the calvaria. For this reason, we used intravital fluorescence microscopy to investigate the effects of heat shock priming on the microcirculation of the periosteum over a period of several days.
Fifty-two Lewis rats were randomized into eight groups. Six groups underwent heat shock priming of the periosteum of the calvaria at 42.5°C, two of them (n = 8) for 15 minutes, two (n = 8) for 25 minutes and two (n = 8) for 35 minutes. After 24 hours, a periosteal chamber was implanted into the heads of the animals of one of each of the two groups mentioned above. Microcirculation and inflammatory responses were studied repeatedly over a period of 14 days using intravital fluorescence microscopy. The expression of heat shock protein (HSP) 70 was examined by immunohistochemistry in three further groups 24 hours after a 15-minute (n = 5), a 25-minute (n = 5) or a 35-minute (n = 5) heat shock treatment. Two groups that did not undergo priming were used as controls. One control group (n = 8) was investigated by intravital microscopy and the other (n = 5) by immunohistochemistry.
During the entire observation period of 14 days, the periosteal chambers revealed physiological microcirculation of the periosteum of the calvaria without perfusion failures. A significant (p < 0.05) and continuous increase in functional capillary density was noted from day 5 to day 14 after 25-minute heat shock priming. Whereas a 15-minute exposure did not lead to an increase in functional capillary density, 35-minute priming caused a significant but reversible perfusion failure in capillaries. Non-perfused capillaries in the 35-minute treatment group were reperfused by day 10. Immunohistochemistry demonstrated an increase in cytoprotective HSP70 expression in the periosteum after a 15-minute and a 35-minute heat shock pretreatment when compared with the control group. The level of HSP70 expression that was measured in the periosteum after 25 minutes of treatment was significantly higher than the levels observed after 15 or 35 minutes of heat shock exposure.
A few days after heat shock priming over an appropriate period of time, a continuous increase in functional capillary density is seen in the periosteum of the calvaria. This increase in perfusion appears to be the result of the induction of angiogenesis.
Heat shock; periosteum; animal; intravital microscopy; calvaria; microcirculation
The quality of the interdisciplinary interface in oncological treatment between surgery, pathology and radiotherapy is mainly dependent on reliable anatomical three-dimensional (3D) allocation of specimen and their context sensitive interpretation which defines further treatment protocols. Computer-assisted preoperative planning (CAPP) allows for outlining macroscopical tumor size and margins. A new technique facilitates the 3D virtual marking and mapping of frozen sections and resection margins or important surgical intraoperative information. These data could be stored in DICOM format (Digital Imaging and Communication in Medicine) in terms of augmented reality and transferred to communicate patient's specific tumor information (invasion to vessels and nerves, non-resectable tumor) to oncologists, radiotherapists and pathologists.
A 63 year-old male with a huge odontogenic lesion of sinus maxillaris was treated with computer-assisted surgery. After resection of the odontogenic lesion, the sinus wall was reconstructed with a prebended 3D titanium-mesh using CAD/CAM technique. This work provides a new treatment device for maxillary reconstruction via rapid prototyping procedures.
Computer-assisted surgery; rapid prototyping; ondontogenic lesion
The extent of wound contamination in gunshot injuries is still a topic of controversial debate. The purpose of the present study is to develop a model that illustrates the contamination of wounds with exogenous particles along the bullet path.
Material and methods
To simulate bacteria, radio-opaque barium titanate (3-6 μm in diameter) was atomized in a dust chamber. Full metal jacket or soft point bullets caliber .222 (n = 12, v0 = 1096 m/s) were fired through the chamber into a gelatin block directly behind it. After that, the gelatin block underwent multi-slice CT in order to analyze the permanent and temporary wound cavity.
The permanent cavity caused by both types of projectiles showed deposits of barium titanate distributed over the entire bullet path. Full metal jacket bullets left only few traces of barium titanate in the temporary cavity. In contrast, the soft point bullets disintegrated completely, and barium titanate covered the entire wound cavity.
Deep penetration of potential exogenous bacteria can be simulated easily and reproducibly with barium titanate particles shot into a gelatin block. Additionally, this procedure permits conclusions to be drawn about the distribution of possible contaminants and thus can yield essential findings in terms of necessary therapeutic procedures.
gunshot; infection; basic research; radiology
Reconstruction of large mandiblular defects following ablative oncologic surgery could be done by using vascularized bone transfer or, more often, primarily with simultaneous or delayed bone grafting, using load bearing reconstruction plates. Bending of these reconstruction plates is typically directed along the outer contour of the original mandible. Simultaneously or in a second operation vascularized or non-vascularized bone is fixed to the reconstruction plate. However, the prosthodontic-driven backward planning to ease bony reconstruction of the mandible in terms of dental rehabilitation using implant-retained overdentures might be an eligible solution. The purpose of this work was to develop, establish and clinically evaluate a novel 3D planning procedure for mandibular reconstruction.
Materials and methods
Three patients with tumors involving the mandible, which included squamous cell carcinoma in the floor of the mouth and keratocystic odontogenic tumor, were treated surgically by hemimandibulectomy.
In primary alloplastic mandible reconstruction, shape and size of the reconstruction plate could be predefined and prebent prior to surgery.
This study provides modern treatment strategies for mandibular reconstruction.
Mandibular reconstruction; backward planning; patient specific implant; computer-assisted surgery