BACKGROUND Extraction of impacted third molars often leads to severe complications caused by damage to the inferior alveolar nerve(IAN).AIM To proposes a method for the partial grinding of an impacted mandibular third...BACKGROUND Extraction of impacted third molars often leads to severe complications caused by damage to the inferior alveolar nerve(IAN).AIM To proposes a method for the partial grinding of an impacted mandibular third molar(IMM3)near the IAN to prevent IAN injury during IMM3 extraction.METHODS Between January 1996 and March 2022,25 patients with IMM3 roots near the IAN were enrolled.The first stage of the operation consisted of grinding a major part of the IMM3 crown with a high-speed turbine dental drill to achieve sufficient space between the mandibular second molar and IMM3.After 6 months,when the root tips were observed to be away from the IAN on X-ray examination,the remaining part of the IMM3 was completely removed.RESULTS All IMM3s were extracted easily without symptoms of IAN injury after extraction.CONCLUSION Partial IMM3 grinding may be a good alternative treatment option to avoid IAN injury in high-risk cases.展开更多
Objective Ureteral lesions caused by impacted ureteral stones are likely to result in postoperative ureteral stricture.On this basis,the study aimed to investigate if dual-energy spectral computed tomography can predi...Objective Ureteral lesions caused by impacted ureteral stones are likely to result in postoperative ureteral stricture.On this basis,the study aimed to investigate if dual-energy spectral computed tomography can predict ureteral hardening caused by impacted stones and to explore the relationship between different types of ureteral lesions and the risk of ureteral stricture.Methods This prospective study collected data of 93 patients with impacted stones from hospital automation system during January 2018 to October 2019.They underwent an abdominal scan on a dual-energy spectral computed tomography.During surgery,the operator used ureteroscopy to identify ureteral lesions,which were classified into four categories:edema,polyps,pallor,and hardening.Seven months later,90 patients were reviewed for the degree of hydronephrosis.Results Endoscopic observations revealed 38(41%)cases of ureteral edema,20(22%)cases of polyps,13(14%)cases of pallor,and 22(24%)cases of hardening.There were significant differences in hydronephrosis,the period of impaction,the calcium concentration of the ureter,and the slope of the spectral Hounsfield unit curve between the four groups.After that,we evaluated the factors associated with ureteral hardening and found that the calcium concentration of the ureter and hydronephrosis remained independent predictors of ureteral hardening.Receiver operating characteristic curve analysis showed that 5.3 mg/cm^(3)calcium concentration of the ureter is an optimal cut-off value to predict ureteral hardening.The result of follow-up showed that 80 patients had complete remission of hydronephrosis,with a complete remission rate of 61.9%(13/21)in the hardening group and 97.1%(67/69)in the non-hardening group(p<0.001).Conclusion Calcium concentration of the ureter is an independent predictor of ureteral hardening.Patients with ureteral hardening have more severe hydronephrosis after ureteroscopic lithotripsy.When the calcium concentration of the ureter is less than 5.3 mg/cm^(3),ureteral lesions should be actively treated.展开更多
Target made of 2519-T87 aluminum alloy was obliquely impacted by a projectile. Microstructural evolution around the crater was investigated by optical microscopy （OM）, transmission electron microscopy （TEM）, and e...Target made of 2519-T87 aluminum alloy was obliquely impacted by a projectile. Microstructural evolution around the crater was investigated by optical microscopy （OM）, transmission electron microscopy （TEM）, and electron backscattered diffraction （EBSD）. The micro-hardness distribution near the crater after impact was studied. The results indicate that at the entering stage, the amount of adiabatic shear band （ASB） is the most, and the precipitates are as fine as those of the target material; the micro-hardness is higher than that at the other stages. At the stable-running stage, the amount of ASB reduces as the micro-bands increase; the precipitates tend to coarsen, which leads to the decrease of the micro-hardness. At the leaving stage, there is a large amount of micro-bands; the precipitates are refined, and the micro-hardness is higher than that at the stable-running stage. The difference in the micro-hardness of the impact stages is due to work hardening and precipitate coarsening, which is caused by adiabatic temperature rise in the alloy.展开更多
Summary： The purpose of this study was to develop a new way to localize the impacted canines from three dimensions and to investigate the root resorption of the adjacent teeth by using cone beam computed tomography ...Summary： The purpose of this study was to develop a new way to localize the impacted canines from three dimensions and to investigate the root resorption of the adjacent teeth by using cone beam computed tomography （CBCT）. Forty-six patients undergoing orthodontic treatments and having impacted canines in Tongii Hospital were examined. The images of CBCT scans were obtained from KaVo 3D exam vision. Angular and linear measurements of the cusp tip and root apex according to the three planes （mid-sagittal, occlusal and frontal） have been taken using the cephalometric tool of the InVivo Dental Anatomage Version 5.1.10. The measurements of the angular and linear coordinates of the maxillary and mandibular canines were obtained. Using this technique the operators could envision the location of the impacted canine according to the three clinical planes. Adjacent teeth root resorption.of 28.26 % was in the upper lateral incisors while 17.39% in upper central incisors, but no lower root resorption was found in our samples. Accurate and reliable localization of the impacted canines could be obtained from the novel analysis system, which offers a better surgical and orthodontic treatment for the patients with impacted canines.展开更多
Based on ANSYS/LS-DYNA, the dynamics analysis software, and using nonlinear dynamic finite element method, the process of a submarine pipeline impacted by dropped objects is simulated, Some conclusions are drawn： Fir...Based on ANSYS/LS-DYNA, the dynamics analysis software, and using nonlinear dynamic finite element method, the process of a submarine pipeline impacted by dropped objects is simulated, Some conclusions are drawn： First, the damage depth of suspended pipe is smaller than that of the bare pipe in case of the same fall energy, and with the increase of fall energy, the difference grows; Second, with the falling object＇s speed and mass rising, the deformation of pipeline intensifies at the impact site and the maximum vibration amplitude of submarine pipeline increases; Third, when the fall energy is equal, the smaller the contact area of falling objects and pipeline is, the greater the damage depth of pipeline becomes; Fourth, changes of seabed soil parameters （shear elastic modulus, internal friction angle, density） have less influence on the suspended pipeline＇s dent depths and maximum vibration amplitude,展开更多
AIM： To verify the safety and efficacy of plasma shock wave lithotripsy （PSWL） in fragmenting impacted stones in the bile duct system. METHODS： From September 1988 to April 2005, 67 patients （26 men and 41 women...AIM： To verify the safety and efficacy of plasma shock wave lithotripsy （PSWL） in fragmenting impacted stones in the bile duct system. METHODS： From September 1988 to April 2005, 67 patients （26 men and 41 women） with impacted stones underwent various biliary operations with tube （or T-tube） drainage. Remnant and impacted stones in the bile duct system found by cholangiography after the operation were fragmented by PSWL and choledochofiberscopy. A total of 201 impacted stones were fragmented by PSWL setting the voltage at 2.5-3.5 kV, and the energy output at 2-3.1 for each pulse of PSWL. Then the fragmented stones were extracted by choledochofiberscopy. The safety and efficacy of PSWL were observed during and after the procedure. RESULTS： One hundred and ninety-nine of 201 impacted stones （99.0%） in the bile duct system were successfully fragmented using PSWL and extracted by choledochofiberscopy. The stone clearance rate for patients was 97% （65/67）. Ten patients felt mild pain in the right upper quadrant of the abdomen, and could tolerate it well. Eleven patients had a small amount of bleeding from the mucosa of the bile duct. The bleeding was transient and stopped spontaneously within 2 min of normal saline irrigation. There were no significant complications during and after the procedure. CONCLUSION：PSWL is a safe and effective method for fragmenting impacted stones in the bile duct system.展开更多
Extraction of the lower third molar is one of the most common procedures performed in oral surgery. In general, impacted tooth extraction involves sectioning the tooth’s crown and roots. In order to divide the impact...Extraction of the lower third molar is one of the most common procedures performed in oral surgery. In general, impacted tooth extraction involves sectioning the tooth’s crown and roots. In order to divide the impacted tooth so that it can be extracted, high-speed air turbine drills are frequently used. However, complications related to air turbine drills may occur. In this report, we propose an alternative tooth sectioning method that obviates the need for air turbine drill use by using a low-speed straight handpiece and carbide bur. A 21-year-old female patient presented to the institute’s dental hospital complaining of symptoms localized to the left lower third molar tooth that were suggestive of impaction. After physical examination, tooth extraction of the impacted left lower third molar was proposed and the patient consented to the procedure. The crown was divided using a conventional straight low-speed handpiece and carbide bur. This carbide bur can easily cut through the enamel of crown. On post-operative day number five, suture was removed and the wound was extremely clear. This technique could minimise intra-operative time and reduce the morbidity associated with air turbine drill assisted lower third molar extraction.展开更多
The existing models are established based on the fatigue behavior of impacted laminates.It makes them unsuitable for the general use.So,a general 3-D progressive damage fatigue life prediction method for impacted lami...The existing models are established based on the fatigue behavior of impacted laminates.It makes them unsuitable for the general use.So,a general 3-D progressive damage fatigue life prediction method for impacted laminates is developed based on the progressive damage theory and the fatigue behavior of unimpacted unidirectional plies.The model can predict the fatigue life of laminated composites with different ply parameters,geometry,impact damage,and fatigue loading conditions.In order to obtain the impact damage information in the case that no impact test data is available,a whole damage process analysis method for laminated composites under the impact loading and the fatigue loading is analyzed.The predicted damage statuses of composite laminates can be used to analyze the post-impact fatigue life.A parametric modeling program is developed to predict the impact damage process and the fatigue life of impacted laminates based on the whole damage process analysis method.The most relative error between the prediction and the test results is 7.78%.展开更多
BACKGROUND Morphological anomalies of teeth,including talon cusp,dens evaginatus,gemination,fusion,concrescence,root dilaceration,and taurodontism,always involve changes in the enamel,cementum and dentin.Diagnosing co...BACKGROUND Morphological anomalies of teeth,including talon cusp,dens evaginatus,gemination,fusion,concrescence,root dilaceration,and taurodontism,always involve changes in the enamel,cementum and dentin.Diagnosing concrescent teeth through routine clinical examination alone is difficult,and most cases of concrescence are found accidentally during extraction.A definite preoperative diagnosis of concrescence would contribute to a better treatment plan and fewer undesirable complications CASE SUMMARY A 47-year-old woman who complained of left maxillary first molar loss for half a year presented to our department seeking treatment by dental implant restoration.Panoramic radiography and cone-beam computed tomography(CBCT)showed an unclear boundary between the distal root of the second molar and the mesial root of the third molar.The teeth were extracted under local anesthesia,and a definite diagnosis of concrescence was made by histopathological examination.CONCLUSION CBCT is a useful tool for diagnosing and planning the management of tooth concrescence and may be beneficial for reducing unnecessary complications.展开更多
Objective: This study aims to estimate the prevalence of impacted maxillary canines using panoramic radiographs. Methods: A sample of 1321 panoramic radiographs were retrospectively examined for the presence of impact...Objective: This study aims to estimate the prevalence of impacted maxillary canines using panoramic radiographs. Methods: A sample of 1321 panoramic radiographs were retrospectively examined for the presence of impacted maxillary canines. The radiographs were obtained from the records of a private dental clinic from the year 2009 till 2016. Results: The prevalence of impacted canines among the examined population (n = 1321) was found to be 1.8%. There was a significant association between gender and canine impaction (P 0.05) difference in the prevalence of right or left canine impaction was found. Conclusion: The prevalence of impacted maxillary canines (1.8%) in this study was within the range reported among other populations.展开更多
The study is aimed at evaluating the effectiveness of phytoremediation in the management of oil impacted soil in Ekpan communities of Delta state, Nigeria. To do this, the study adopted an experimental research design...The study is aimed at evaluating the effectiveness of phytoremediation in the management of oil impacted soil in Ekpan communities of Delta state, Nigeria. To do this, the study adopted an experimental research design that involve the use of phytoremediation (carpet grass Axonopus compressus) and nutsedge Cyperus rotundus) in the management of petroleum impacted soil site in Ekpan, This experiment spans for three months periods (one planting season). It involves the treatment of the oil impacted site with different plant species and soil amendments. Laboratory analysis of the soil samples was conducted to determine the effect of phytoremediation and soil amendments on hydrocarbon loss in oil impacted sites. The study revealed that the combined effect of Axonopus sp., Cyperus sp. and oil amendments accounted for 59% reduction in hydrocarbon. However Axonopus sp. and Cyperus sp. accounted for 47% and 48% reduction in hydrocarbon respectively. This shows that though, both plant species can be used successfully as a phytoremediation technique for the reclamation of oil impacted soils, but Axonopus sp. and Cyperus sp. was the most effective when applied with soil amendment (organic and inorganic manure). It is therefore recommended that iindigenous plant species (particularly Axonopus sp. and Cyperus sp.) should be used together with soil amendments in phytoremediation rather than the traditional bioremediation involving the use of microorganism. Oil companies operating in the Niger Delta region of Nigeria are encouraged not only to carry out physical clean-up of oil spills but should also carry out bioremediation to restore the environment back to its natural or near natural state. The methodology adopted in this study could be followed by oil companies to manage oil impacted soils in the Niger-Delta environment in Nigeria and indeed everywhere in the world.展开更多
Aim of the study was to evaluate if there is a constant and significant reduction in traumaticity when mas- sively traumatic oral surgical procedures such as the removal of third molars are conducted with only ul- tra...Aim of the study was to evaluate if there is a constant and significant reduction in traumaticity when mas- sively traumatic oral surgical procedures such as the removal of third molars are conducted with only ul- trasonic surgical devices (Piezotomes) expressed in a reduction of postsurgical pain and swelling on the patient’s side since such clinical experiences by the authors suggested this. Since oral surgeons criticize a higher time consumption for surgeries with Piezoto- mes also the objective time consumption was evalu- ated and compared to the traditional methods. Mate- rial and Methods: 56 female and male patients were selected that already underwent a removal of an im- pacted third mandibular molar on one side with rota- ry instruments by bone destructive burring with a still persisting comparable third mandibular molar on the contralateral side complaining about recur- rent pain episodes and were already documented for pain and swelling before. The ultrasonic surgical re- moval with the Piezotome was conducted with a buc- cal osteotomy of the compacta lateral to the impacted third molar, preservation of the resected compacta in saline solution, removal of the third molar by single or multiple dentotomy and full anatomical restitution of the surgical site with the preserved buccal com- pacta. The swelling was documented by kephalome- try 24/48/72 hours and 1 week post surgery, the pain index by the total consumption of ibuprofen-400 mg—tablets. Lesions of the mandible nerve were documented. Netto surgery time was taken from the first incision to the last suture of the procedure. Re-sults: 6 patients had to be excluded from evaluation due to incomplete post surgical follow up. A signify-cant (***, p > 0.999) decrease in pain and swelling of 50% was detected both for the parameters swelling and pain with Piezotome-surgery. No lesions of the mandible nerve were detected with Piezotome sur- gery whereas surgery with rotary instruments re- sulted in 16% hypesthesia at least up to one week. Although netto surgery time was approximately 50% longer when done with the Piezotome at the begin-ning the time consumption normalized with the growing experience of the surgeons back to the time schedule when surgery was performed with rotary instruments revealing no significant differences (-, p < 0.73). Conclusions: The results of this retrospective study suggest that Piezotome-surgery is superior in atraumaticity and soft-tissue safety compared to tra- ditional procedures with burs and grants the patients significantly less post surgical pain and swelling. Al- though—as it is with all new surgical tools and pro- tocols—surgery time is longer at the beginning when purely working with ultrasonic surgical devices time consumption reduces to normal values after a learn- ing curve.展开更多
We present the case of a 46-year old man with a two-year history of losing his denture presenting with cachexia and a two-month history of dysphagia to both liquids and solids associated with odynophagia. Review at th...We present the case of a 46-year old man with a two-year history of losing his denture presenting with cachexia and a two-month history of dysphagia to both liquids and solids associated with odynophagia. Review at the ENT department where a diagnostic rigid oesophagoscopy was done under general anaesthesia showed a denture impacted to the wall of the oesophagus at 17 cm from the incisor. Attempts at retrieval were unsuccessful as the denture was deeply embedded in the oesophageal wall <em>and bled easily on attempted removal</em>. He subsequently underwent a 2-stage surgical management approach by the cardiothoracic surgical team. Patient first underwent nutritional rehabilitation for a month through a created feeding gastrostomy tube via a limited midline laparotomy. He then had a open cervical oesophagotomy and removal of the denture. Currently doing well six months after surgery and tolerating normal oral diet.展开更多
This case presents an unusual transposition of an impacted canine on the central incisor that provides a multidisciplinary approach to its resolution. The patient comes to the consultation for mobility of the central ...This case presents an unusual transposition of an impacted canine on the central incisor that provides a multidisciplinary approach to its resolution. The patient comes to the consultation for mobility of the central incisor. Clinically, tooth mobility was confirmed with tooth crowding and persistence of the temporary canine. Cone beam tomography (CBCT) observed the atypical position of the permanent canine that caused root resorption of the ipsilateral central incisor and the need to extract both teeth. The conservative treatment of the bone structures during the dental enucleation of the impacted canine carried out by odontosection and the immediate bone grafting of the defect projected an acceptable regeneration of the bone volume for the insertion of the implant. The orthodontic treatment managed to correct the bite, position the upper premolar in the place of the canine tooth and maintain the space to place the implant in the central incisor. The three-year follow-up shows maintenance of the peri-implant crestal bone level, the success of orthodontic treatment with recovery of the patient’s function and aesthetics.展开更多
Physicians under-report cases of child abuse or child maltreatment. We present a case of an impacted oesophageal foreign body in a physically abused child. S.H. is a 7-year-old male child who accidentally ingested met...Physicians under-report cases of child abuse or child maltreatment. We present a case of an impacted oesophageal foreign body in a physically abused child. S.H. is a 7-year-old male child who accidentally ingested metal clip while being assaulted by his paternal uncle whom he resides with. He presented with dysphagia, odynophagia and drooling of saliva and urgent x-ray soft tissue neck revealing the presence of the metallic foreign body in the prevertebral region. He had emergency oesophagoscopy with the removal of foreign body, did well and was discharged home 4th day postoperatively after parental counselling. It remains the responsibility of paediatric healthcare providers to consider child maltreatment as a differential diagnosis of any unexplained injury or medical problems, including oesophageal foreign body impaction.展开更多
Objective: To study the local inflammatory stress response and pain mediator secretion after impacted wisdom tooth extraction with high-speed turbine drill combined with original luxator. Methods: Patients who receive...Objective: To study the local inflammatory stress response and pain mediator secretion after impacted wisdom tooth extraction with high-speed turbine drill combined with original luxator. Methods: Patients who received impacted wisdom tooth extraction in the First People's Hospital ofYunnan Province between March 2014 and June 2017 were selected as the research objects and randomly divided into the observation group who accepted impacted wisdom tooth extraction with high-speed turbine drill combined with original luxator and the control group who accepted impacted wisdom tooth extraction with traditional chisel. The contents of inflammatory mediators, stress mediators and pain mediators in gingival crevicular fluid were measured before surgery and 3 days after surgery. Results: Three days after surgery, PTX3, ICAM1, MPO, PGE2, PPARγ, ROS, MDA, 5-HT, CGRP, SP, Gal and ATP contents in gingival crevicular fluid of both groups were higher than those before surgery whereas GPx and T-AOC contents were significantly lower than those before surgery, and PTX3, ICAM1, MPO, PGE2, PPARγ, ROS, MDA, 5-HT, CGRP, SP, Gal and ATP contents in gingival crevicular fluid of observation group were lower than those of control group whereas GPx and T-AOC contents were significantly higher than those of control group. Conclusions: The impacted wisdom tooth extraction with high-speed turbine drill combined with original luxator can reduce the local inflammatory stress response and inhibit the secretion of pain mediators.展开更多
2017 is an election year for Europe,also a year on which hinges the destiny of Europe.In view of the general rise of right-wing populist parties in the EU,there have been concerns if another'black swan'would f...2017 is an election year for Europe,also a year on which hinges the destiny of Europe.In view of the general rise of right-wing populist parties in the EU,there have been concerns if another'black swan'would fly out of the general elections of the Netherland,France and Germany.To date,the Dutch and French展开更多
Background: Despite scientific and technological developments on dentistry, man is still losing their teeth due to several reasons. Tooth loss may result in esthetical and functional discrepancies. Although beginning ...Background: Despite scientific and technological developments on dentistry, man is still losing their teeth due to several reasons. Tooth loss may result in esthetical and functional discrepancies. Although beginning of dental transplantation is quite old, it started to take attraction on scientific basis recently. In recent years, oral implants are being used nearly in all fields of dentistry. Purpose: The purpose of this study was to evaluate 5 year follow-up of a patient with an impacted maxillary canine transplantation and a single-tooth implant. Materials and Methods: In our study an impacted canine was removed and transplanted immediately. Thereafter the missing premolar was replaced by an implant retained cemented crown. The patient was evaluated clinically and radiographically. Clinical periodontal parameters and implant mobility was evaluated, marginal bone level was measured on radiographs. Results: No significant changes have been observed in these parameters and implant mobility between year one and year five of the study. Conclusion: This study has demonstrated that stable long-term results can be achieved with replacement of single teeth with MIS Implant, and cemented crown on abutment with adjacent transplanted canine, with cumulative success rate for five years.展开更多
Aim: Canines are the second most impacted teeth in jaws after third molars. Perforation of the anatomic structures, such as maxillary sinus and nasal fossa, are some of the complications of the surgery. In this case, ...Aim: Canines are the second most impacted teeth in jaws after third molars. Perforation of the anatomic structures, such as maxillary sinus and nasal fossa, are some of the complications of the surgery. In this case, bilateral maxillary impacted canines’ extraction, with the guidance of CBCT is done without any complication. Case: A 24-year-old female patient was referred to Istanbul University, Oral and Maxillofacial Surgery. Left and right deciduous canines and swelling at the right maxillary canine’s labial area were seen during the intraoral examination. Bilateral impacted canines were determined after evaluating the present CBCT images of the patient and orthodontic treatment was advised to the patient. Due to the refusal of orthodontic treament, extractions of the impacted teeth were decided. After the evaluation of CBCT images, the maxillary right canine was determined at the labial site while the maxillary left canine was determined at the palatinale site. Results: Right maxillary canine was lying between the right first incisor and right first molar and It was extracted with mucoperiosteal vestibule flap procedure. For the extraction, the tooth was divided into two pieces from the enamel-cement junction. Left maxillary canine was lying between the left first incisor and left first molar and It was extracted with mucoperiosteal palatinale flap procedure. Flap was stitched primarly with 3/0 silk sutures. Palatinal plaque, which was prepared before the surgery, was applied. Antibiotic, analgesic and moutwash were prescribed to the patient. 1 week following the surgery, stitches were removed and the healing was optimal. Conclusion: Impacted canines are a common clinic condition which requires a multi-discipliner approach. CBCT can increase the success of the treatment by preventing possible complications with determining the proximity of the anatomical structures and the localization of the impacted teeth. There were no sign of complication and the healing was optimal.展开更多
Three different kinds of PELE(the penetrator with lateral efficiency) were launched by ballistic artillery to impact the multi-layer spaced metal target plates.The lmpact velocities of the projectiles were measured by...Three different kinds of PELE(the penetrator with lateral efficiency) were launched by ballistic artillery to impact the multi-layer spaced metal target plates.The lmpact velocities of the projectiles were measured by the velocity measuring system.The damage degree and process of each laye r of target plate impacted by the three kinds of projectiles were analyzed.The experimental results show that all the three kinds of projectiles have the effect of expanding holes on the multi-layer spaced metal target plates.For the normal structure PELE(without layered) with tungsten alloy jacket and the radial layered PELE with tungsten alloy jacket,the diameters of holes on the seco nd layer of plates are 3.36 times and 3.76 times of the diameter of the projectile,re spectively.For radial layered PELE with W/Zr-based amorphous composite jacket,due to the large number of tungsten wires dispersed after the impact,the diameter of the holes on the four-layer spaced plates can reach 2.4 times,3.04 times,5.36 times and 2.68 times of the diameter of the projectile.Besides,the normal structure PELE with tungsten alloy jacket and the radial layered PELE whit tungsten alloy jacket formed a large number of fragments impact marks on the third target plate.Although the number of fragments penetrating the third target plate is not as large as that of the normal structure PELE,the area of dispersion of fragments impact craters on the third target plate is larger by the radial layered PELE.The radial layered PELE with W/Zr-based amorphous composite jacket released a lot of heat energy due to the impact of the matrix material,and formed a large area of ablation marks on the last three target plates.展开更多
文摘BACKGROUND Extraction of impacted third molars often leads to severe complications caused by damage to the inferior alveolar nerve(IAN).AIM To proposes a method for the partial grinding of an impacted mandibular third molar(IMM3)near the IAN to prevent IAN injury during IMM3 extraction.METHODS Between January 1996 and March 2022,25 patients with IMM3 roots near the IAN were enrolled.The first stage of the operation consisted of grinding a major part of the IMM3 crown with a high-speed turbine dental drill to achieve sufficient space between the mandibular second molar and IMM3.After 6 months,when the root tips were observed to be away from the IAN on X-ray examination,the remaining part of the IMM3 was completely removed.RESULTS All IMM3s were extracted easily without symptoms of IAN injury after extraction.CONCLUSION Partial IMM3 grinding may be a good alternative treatment option to avoid IAN injury in high-risk cases.
文摘Objective Ureteral lesions caused by impacted ureteral stones are likely to result in postoperative ureteral stricture.On this basis,the study aimed to investigate if dual-energy spectral computed tomography can predict ureteral hardening caused by impacted stones and to explore the relationship between different types of ureteral lesions and the risk of ureteral stricture.Methods This prospective study collected data of 93 patients with impacted stones from hospital automation system during January 2018 to October 2019.They underwent an abdominal scan on a dual-energy spectral computed tomography.During surgery,the operator used ureteroscopy to identify ureteral lesions,which were classified into four categories:edema,polyps,pallor,and hardening.Seven months later,90 patients were reviewed for the degree of hydronephrosis.Results Endoscopic observations revealed 38(41%)cases of ureteral edema,20(22%)cases of polyps,13(14%)cases of pallor,and 22(24%)cases of hardening.There were significant differences in hydronephrosis,the period of impaction,the calcium concentration of the ureter,and the slope of the spectral Hounsfield unit curve between the four groups.After that,we evaluated the factors associated with ureteral hardening and found that the calcium concentration of the ureter and hydronephrosis remained independent predictors of ureteral hardening.Receiver operating characteristic curve analysis showed that 5.3 mg/cm^(3)calcium concentration of the ureter is an optimal cut-off value to predict ureteral hardening.The result of follow-up showed that 80 patients had complete remission of hydronephrosis,with a complete remission rate of 61.9%(13/21)in the hardening group and 97.1%(67/69)in the non-hardening group(p<0.001).Conclusion Calcium concentration of the ureter is an independent predictor of ureteral hardening.Patients with ureteral hardening have more severe hydronephrosis after ureteroscopic lithotripsy.When the calcium concentration of the ureter is less than 5.3 mg/cm^(3),ureteral lesions should be actively treated.
基金Project (201191107) supported by Science and Technology Plan of Xinjiang,China
文摘Target made of 2519-T87 aluminum alloy was obliquely impacted by a projectile. Microstructural evolution around the crater was investigated by optical microscopy （OM）, transmission electron microscopy （TEM）, and electron backscattered diffraction （EBSD）. The micro-hardness distribution near the crater after impact was studied. The results indicate that at the entering stage, the amount of adiabatic shear band （ASB） is the most, and the precipitates are as fine as those of the target material; the micro-hardness is higher than that at the other stages. At the stable-running stage, the amount of ASB reduces as the micro-bands increase; the precipitates tend to coarsen, which leads to the decrease of the micro-hardness. At the leaving stage, there is a large amount of micro-bands; the precipitates are refined, and the micro-hardness is higher than that at the stable-running stage. The difference in the micro-hardness of the impact stages is due to work hardening and precipitate coarsening, which is caused by adiabatic temperature rise in the alloy.
文摘Summary： The purpose of this study was to develop a new way to localize the impacted canines from three dimensions and to investigate the root resorption of the adjacent teeth by using cone beam computed tomography （CBCT）. Forty-six patients undergoing orthodontic treatments and having impacted canines in Tongii Hospital were examined. The images of CBCT scans were obtained from KaVo 3D exam vision. Angular and linear measurements of the cusp tip and root apex according to the three planes （mid-sagittal, occlusal and frontal） have been taken using the cephalometric tool of the InVivo Dental Anatomage Version 5.1.10. The measurements of the angular and linear coordinates of the maxillary and mandibular canines were obtained. Using this technique the operators could envision the location of the impacted canine according to the three clinical planes. Adjacent teeth root resorption.of 28.26 % was in the upper lateral incisors while 17.39% in upper central incisors, but no lower root resorption was found in our samples. Accurate and reliable localization of the impacted canines could be obtained from the novel analysis system, which offers a better surgical and orthodontic treatment for the patients with impacted canines.
文摘Based on ANSYS/LS-DYNA, the dynamics analysis software, and using nonlinear dynamic finite element method, the process of a submarine pipeline impacted by dropped objects is simulated, Some conclusions are drawn： First, the damage depth of suspended pipe is smaller than that of the bare pipe in case of the same fall energy, and with the increase of fall energy, the difference grows; Second, with the falling object＇s speed and mass rising, the deformation of pipeline intensifies at the impact site and the maximum vibration amplitude of submarine pipeline increases; Third, when the fall energy is equal, the smaller the contact area of falling objects and pipeline is, the greater the damage depth of pipeline becomes; Fourth, changes of seabed soil parameters （shear elastic modulus, internal friction angle, density） have less influence on the suspended pipeline＇s dent depths and maximum vibration amplitude,
文摘AIM： To verify the safety and efficacy of plasma shock wave lithotripsy （PSWL） in fragmenting impacted stones in the bile duct system. METHODS： From September 1988 to April 2005, 67 patients （26 men and 41 women） with impacted stones underwent various biliary operations with tube （or T-tube） drainage. Remnant and impacted stones in the bile duct system found by cholangiography after the operation were fragmented by PSWL and choledochofiberscopy. A total of 201 impacted stones were fragmented by PSWL setting the voltage at 2.5-3.5 kV, and the energy output at 2-3.1 for each pulse of PSWL. Then the fragmented stones were extracted by choledochofiberscopy. The safety and efficacy of PSWL were observed during and after the procedure. RESULTS： One hundred and ninety-nine of 201 impacted stones （99.0%） in the bile duct system were successfully fragmented using PSWL and extracted by choledochofiberscopy. The stone clearance rate for patients was 97% （65/67）. Ten patients felt mild pain in the right upper quadrant of the abdomen, and could tolerate it well. Eleven patients had a small amount of bleeding from the mucosa of the bile duct. The bleeding was transient and stopped spontaneously within 2 min of normal saline irrigation. There were no significant complications during and after the procedure. CONCLUSION：PSWL is a safe and effective method for fragmenting impacted stones in the bile duct system.
文摘Extraction of the lower third molar is one of the most common procedures performed in oral surgery. In general, impacted tooth extraction involves sectioning the tooth’s crown and roots. In order to divide the impacted tooth so that it can be extracted, high-speed air turbine drills are frequently used. However, complications related to air turbine drills may occur. In this report, we propose an alternative tooth sectioning method that obviates the need for air turbine drill use by using a low-speed straight handpiece and carbide bur. A 21-year-old female patient presented to the institute’s dental hospital complaining of symptoms localized to the left lower third molar tooth that were suggestive of impaction. After physical examination, tooth extraction of the impacted left lower third molar was proposed and the patient consented to the procedure. The crown was divided using a conventional straight low-speed handpiece and carbide bur. This carbide bur can easily cut through the enamel of crown. On post-operative day number five, suture was removed and the wound was extremely clear. This technique could minimise intra-operative time and reduce the morbidity associated with air turbine drill assisted lower third molar extraction.
文摘The existing models are established based on the fatigue behavior of impacted laminates.It makes them unsuitable for the general use.So,a general 3-D progressive damage fatigue life prediction method for impacted laminates is developed based on the progressive damage theory and the fatigue behavior of unimpacted unidirectional plies.The model can predict the fatigue life of laminated composites with different ply parameters,geometry,impact damage,and fatigue loading conditions.In order to obtain the impact damage information in the case that no impact test data is available,a whole damage process analysis method for laminated composites under the impact loading and the fatigue loading is analyzed.The predicted damage statuses of composite laminates can be used to analyze the post-impact fatigue life.A parametric modeling program is developed to predict the impact damage process and the fatigue life of impacted laminates based on the whole damage process analysis method.The most relative error between the prediction and the test results is 7.78%.
基金Supported by the Applied Basic Research Program of the 920th Hospital of the Joint Logistics Support Force,No.2019YGB15。
文摘BACKGROUND Morphological anomalies of teeth,including talon cusp,dens evaginatus,gemination,fusion,concrescence,root dilaceration,and taurodontism,always involve changes in the enamel,cementum and dentin.Diagnosing concrescent teeth through routine clinical examination alone is difficult,and most cases of concrescence are found accidentally during extraction.A definite preoperative diagnosis of concrescence would contribute to a better treatment plan and fewer undesirable complications CASE SUMMARY A 47-year-old woman who complained of left maxillary first molar loss for half a year presented to our department seeking treatment by dental implant restoration.Panoramic radiography and cone-beam computed tomography(CBCT)showed an unclear boundary between the distal root of the second molar and the mesial root of the third molar.The teeth were extracted under local anesthesia,and a definite diagnosis of concrescence was made by histopathological examination.CONCLUSION CBCT is a useful tool for diagnosing and planning the management of tooth concrescence and may be beneficial for reducing unnecessary complications.
文摘Objective: This study aims to estimate the prevalence of impacted maxillary canines using panoramic radiographs. Methods: A sample of 1321 panoramic radiographs were retrospectively examined for the presence of impacted maxillary canines. The radiographs were obtained from the records of a private dental clinic from the year 2009 till 2016. Results: The prevalence of impacted canines among the examined population (n = 1321) was found to be 1.8%. There was a significant association between gender and canine impaction (P 0.05) difference in the prevalence of right or left canine impaction was found. Conclusion: The prevalence of impacted maxillary canines (1.8%) in this study was within the range reported among other populations.
文摘The study is aimed at evaluating the effectiveness of phytoremediation in the management of oil impacted soil in Ekpan communities of Delta state, Nigeria. To do this, the study adopted an experimental research design that involve the use of phytoremediation (carpet grass Axonopus compressus) and nutsedge Cyperus rotundus) in the management of petroleum impacted soil site in Ekpan, This experiment spans for three months periods (one planting season). It involves the treatment of the oil impacted site with different plant species and soil amendments. Laboratory analysis of the soil samples was conducted to determine the effect of phytoremediation and soil amendments on hydrocarbon loss in oil impacted sites. The study revealed that the combined effect of Axonopus sp., Cyperus sp. and oil amendments accounted for 59% reduction in hydrocarbon. However Axonopus sp. and Cyperus sp. accounted for 47% and 48% reduction in hydrocarbon respectively. This shows that though, both plant species can be used successfully as a phytoremediation technique for the reclamation of oil impacted soils, but Axonopus sp. and Cyperus sp. was the most effective when applied with soil amendment (organic and inorganic manure). It is therefore recommended that iindigenous plant species (particularly Axonopus sp. and Cyperus sp.) should be used together with soil amendments in phytoremediation rather than the traditional bioremediation involving the use of microorganism. Oil companies operating in the Niger Delta region of Nigeria are encouraged not only to carry out physical clean-up of oil spills but should also carry out bioremediation to restore the environment back to its natural or near natural state. The methodology adopted in this study could be followed by oil companies to manage oil impacted soils in the Niger-Delta environment in Nigeria and indeed everywhere in the world.
文摘Aim of the study was to evaluate if there is a constant and significant reduction in traumaticity when mas- sively traumatic oral surgical procedures such as the removal of third molars are conducted with only ul- trasonic surgical devices (Piezotomes) expressed in a reduction of postsurgical pain and swelling on the patient’s side since such clinical experiences by the authors suggested this. Since oral surgeons criticize a higher time consumption for surgeries with Piezoto- mes also the objective time consumption was evalu- ated and compared to the traditional methods. Mate- rial and Methods: 56 female and male patients were selected that already underwent a removal of an im- pacted third mandibular molar on one side with rota- ry instruments by bone destructive burring with a still persisting comparable third mandibular molar on the contralateral side complaining about recur- rent pain episodes and were already documented for pain and swelling before. The ultrasonic surgical re- moval with the Piezotome was conducted with a buc- cal osteotomy of the compacta lateral to the impacted third molar, preservation of the resected compacta in saline solution, removal of the third molar by single or multiple dentotomy and full anatomical restitution of the surgical site with the preserved buccal com- pacta. The swelling was documented by kephalome- try 24/48/72 hours and 1 week post surgery, the pain index by the total consumption of ibuprofen-400 mg—tablets. Lesions of the mandible nerve were documented. Netto surgery time was taken from the first incision to the last suture of the procedure. Re-sults: 6 patients had to be excluded from evaluation due to incomplete post surgical follow up. A signify-cant (***, p > 0.999) decrease in pain and swelling of 50% was detected both for the parameters swelling and pain with Piezotome-surgery. No lesions of the mandible nerve were detected with Piezotome sur- gery whereas surgery with rotary instruments re- sulted in 16% hypesthesia at least up to one week. Although netto surgery time was approximately 50% longer when done with the Piezotome at the begin-ning the time consumption normalized with the growing experience of the surgeons back to the time schedule when surgery was performed with rotary instruments revealing no significant differences (-, p < 0.73). Conclusions: The results of this retrospective study suggest that Piezotome-surgery is superior in atraumaticity and soft-tissue safety compared to tra- ditional procedures with burs and grants the patients significantly less post surgical pain and swelling. Al- though—as it is with all new surgical tools and pro- tocols—surgery time is longer at the beginning when purely working with ultrasonic surgical devices time consumption reduces to normal values after a learn- ing curve.
文摘We present the case of a 46-year old man with a two-year history of losing his denture presenting with cachexia and a two-month history of dysphagia to both liquids and solids associated with odynophagia. Review at the ENT department where a diagnostic rigid oesophagoscopy was done under general anaesthesia showed a denture impacted to the wall of the oesophagus at 17 cm from the incisor. Attempts at retrieval were unsuccessful as the denture was deeply embedded in the oesophageal wall <em>and bled easily on attempted removal</em>. He subsequently underwent a 2-stage surgical management approach by the cardiothoracic surgical team. Patient first underwent nutritional rehabilitation for a month through a created feeding gastrostomy tube via a limited midline laparotomy. He then had a open cervical oesophagotomy and removal of the denture. Currently doing well six months after surgery and tolerating normal oral diet.
文摘This case presents an unusual transposition of an impacted canine on the central incisor that provides a multidisciplinary approach to its resolution. The patient comes to the consultation for mobility of the central incisor. Clinically, tooth mobility was confirmed with tooth crowding and persistence of the temporary canine. Cone beam tomography (CBCT) observed the atypical position of the permanent canine that caused root resorption of the ipsilateral central incisor and the need to extract both teeth. The conservative treatment of the bone structures during the dental enucleation of the impacted canine carried out by odontosection and the immediate bone grafting of the defect projected an acceptable regeneration of the bone volume for the insertion of the implant. The orthodontic treatment managed to correct the bite, position the upper premolar in the place of the canine tooth and maintain the space to place the implant in the central incisor. The three-year follow-up shows maintenance of the peri-implant crestal bone level, the success of orthodontic treatment with recovery of the patient’s function and aesthetics.
文摘Physicians under-report cases of child abuse or child maltreatment. We present a case of an impacted oesophageal foreign body in a physically abused child. S.H. is a 7-year-old male child who accidentally ingested metal clip while being assaulted by his paternal uncle whom he resides with. He presented with dysphagia, odynophagia and drooling of saliva and urgent x-ray soft tissue neck revealing the presence of the metallic foreign body in the prevertebral region. He had emergency oesophagoscopy with the removal of foreign body, did well and was discharged home 4th day postoperatively after parental counselling. It remains the responsibility of paediatric healthcare providers to consider child maltreatment as a differential diagnosis of any unexplained injury or medical problems, including oesophageal foreign body impaction.
文摘Objective: To study the local inflammatory stress response and pain mediator secretion after impacted wisdom tooth extraction with high-speed turbine drill combined with original luxator. Methods: Patients who received impacted wisdom tooth extraction in the First People's Hospital ofYunnan Province between March 2014 and June 2017 were selected as the research objects and randomly divided into the observation group who accepted impacted wisdom tooth extraction with high-speed turbine drill combined with original luxator and the control group who accepted impacted wisdom tooth extraction with traditional chisel. The contents of inflammatory mediators, stress mediators and pain mediators in gingival crevicular fluid were measured before surgery and 3 days after surgery. Results: Three days after surgery, PTX3, ICAM1, MPO, PGE2, PPARγ, ROS, MDA, 5-HT, CGRP, SP, Gal and ATP contents in gingival crevicular fluid of both groups were higher than those before surgery whereas GPx and T-AOC contents were significantly lower than those before surgery, and PTX3, ICAM1, MPO, PGE2, PPARγ, ROS, MDA, 5-HT, CGRP, SP, Gal and ATP contents in gingival crevicular fluid of observation group were lower than those of control group whereas GPx and T-AOC contents were significantly higher than those of control group. Conclusions: The impacted wisdom tooth extraction with high-speed turbine drill combined with original luxator can reduce the local inflammatory stress response and inhibit the secretion of pain mediators.
文摘2017 is an election year for Europe,also a year on which hinges the destiny of Europe.In view of the general rise of right-wing populist parties in the EU,there have been concerns if another'black swan'would fly out of the general elections of the Netherland,France and Germany.To date,the Dutch and French
文摘Background: Despite scientific and technological developments on dentistry, man is still losing their teeth due to several reasons. Tooth loss may result in esthetical and functional discrepancies. Although beginning of dental transplantation is quite old, it started to take attraction on scientific basis recently. In recent years, oral implants are being used nearly in all fields of dentistry. Purpose: The purpose of this study was to evaluate 5 year follow-up of a patient with an impacted maxillary canine transplantation and a single-tooth implant. Materials and Methods: In our study an impacted canine was removed and transplanted immediately. Thereafter the missing premolar was replaced by an implant retained cemented crown. The patient was evaluated clinically and radiographically. Clinical periodontal parameters and implant mobility was evaluated, marginal bone level was measured on radiographs. Results: No significant changes have been observed in these parameters and implant mobility between year one and year five of the study. Conclusion: This study has demonstrated that stable long-term results can be achieved with replacement of single teeth with MIS Implant, and cemented crown on abutment with adjacent transplanted canine, with cumulative success rate for five years.
文摘Aim: Canines are the second most impacted teeth in jaws after third molars. Perforation of the anatomic structures, such as maxillary sinus and nasal fossa, are some of the complications of the surgery. In this case, bilateral maxillary impacted canines’ extraction, with the guidance of CBCT is done without any complication. Case: A 24-year-old female patient was referred to Istanbul University, Oral and Maxillofacial Surgery. Left and right deciduous canines and swelling at the right maxillary canine’s labial area were seen during the intraoral examination. Bilateral impacted canines were determined after evaluating the present CBCT images of the patient and orthodontic treatment was advised to the patient. Due to the refusal of orthodontic treament, extractions of the impacted teeth were decided. After the evaluation of CBCT images, the maxillary right canine was determined at the labial site while the maxillary left canine was determined at the palatinale site. Results: Right maxillary canine was lying between the right first incisor and right first molar and It was extracted with mucoperiosteal vestibule flap procedure. For the extraction, the tooth was divided into two pieces from the enamel-cement junction. Left maxillary canine was lying between the left first incisor and left first molar and It was extracted with mucoperiosteal palatinale flap procedure. Flap was stitched primarly with 3/0 silk sutures. Palatinal plaque, which was prepared before the surgery, was applied. Antibiotic, analgesic and moutwash were prescribed to the patient. 1 week following the surgery, stitches were removed and the healing was optimal. Conclusion: Impacted canines are a common clinic condition which requires a multi-discipliner approach. CBCT can increase the success of the treatment by preventing possible complications with determining the proximity of the anatomical structures and the localization of the impacted teeth. There were no sign of complication and the healing was optimal.
基金supported by National Natural Science Foundation of China(Grant No.11802141)Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX18_0465)。
文摘Three different kinds of PELE(the penetrator with lateral efficiency) were launched by ballistic artillery to impact the multi-layer spaced metal target plates.The lmpact velocities of the projectiles were measured by the velocity measuring system.The damage degree and process of each laye r of target plate impacted by the three kinds of projectiles were analyzed.The experimental results show that all the three kinds of projectiles have the effect of expanding holes on the multi-layer spaced metal target plates.For the normal structure PELE(without layered) with tungsten alloy jacket and the radial layered PELE with tungsten alloy jacket,the diameters of holes on the seco nd layer of plates are 3.36 times and 3.76 times of the diameter of the projectile,re spectively.For radial layered PELE with W/Zr-based amorphous composite jacket,due to the large number of tungsten wires dispersed after the impact,the diameter of the holes on the four-layer spaced plates can reach 2.4 times,3.04 times,5.36 times and 2.68 times of the diameter of the projectile.Besides,the normal structure PELE with tungsten alloy jacket and the radial layered PELE whit tungsten alloy jacket formed a large number of fragments impact marks on the third target plate.Although the number of fragments penetrating the third target plate is not as large as that of the normal structure PELE,the area of dispersion of fragments impact craters on the third target plate is larger by the radial layered PELE.The radial layered PELE with W/Zr-based amorphous composite jacket released a lot of heat energy due to the impact of the matrix material,and formed a large area of ablation marks on the last three target plates.
