850 research outputs found
Replantation of a maxillary second molar after removal of a third molar with a dentigerous cyst: Case report and 12-month follow-up
The aim of this study was to describe the replantation of a maxillary second right molar, which had been removed
for surgical reasons in order to remove a dentigerous cyst associated with the adjacent third molar, and the case's
12-month follow-up.
A 51-year-old man presented swelling in the right maxillary area. Radiographic examination showed a large radiolucency
in close proximity to the third molar, suggesting a follicular cyst. The third molar was extracted and
the cyst underwent curettage. The second molar had to be extracted to enable complete removal of the cyst and to
achieve primary closure of the wound, which would have been impossible without repositioning the molar. With
this objective, extraoral endodontic treatment was performed, the root-end was resected and prepared with ultrasonic
retrotips, and root-end filling was accomplished with MTA before the molar was replanted. At the 12-month
follow-up, the tooth showed no clinical signs or symptoms, probing depth was no greater than 3 mm and radiographic
examination showed no evidence of root resorption or periapical lesion
A Markovian jump system approach for the estimation and adaptive diagnosis of decreased power generation in wind farms
In this study, a Markovian jump model of the power generation system of a wind turbine is proposed and the authors present a closed-loop model-based observer to estimate the faults related to energy losses. The observer is designed through an H∞-based optimisation problem that optimally fixes the trade-off between the observer fault sensitivity and robustness. The fault estimates are then used in data-based decision mechanisms for achieving fault detection and isolation. The performance of the strategy is then ameliorated in a wind farm (WF) level scheme that uses a bank of the aforementioned observers and decision mechanisms. Finally, the proposed approach is tested using a well-known benchmark in the context of WF fault diagnosis
B and B_s decay constants from QCD Duality at three loops
Using special linear combinations of finite energy sum rules which minimize
the contribution of the unknown continuum spectral function, we compute the
decay constants of the pseudoscalar mesons B and B_s. In the computation, we
employ the recent three loop calculation of the pseudoscalar two-point function
expanded in powers of the running bottom quark mass. The sum rules show
remarkable stability over a wide range of the upper limit of the finite energy
integration. We obtain the following results for the pseudoscalar decay
constants: f_B=178 \pm 14 MeV and f_{B_s}=200 \pm 14 MeV. The results are
somewhat lower than recent predictions based on Borel transform, lattice
computations or HQET. Our sum rule approach of exploiting QCD quark hadron
duality differs significantly from the usual ones, and we believe that the
errors due to theoretical uncertainties are smaller
Immediate loading with fixed full-arch prostheses in the maxilla: review of the literature
Objectives: To critically review the evidence-based literature on immediate loading of implants with fixed full-
arch prostheses in the maxilla to determine 1) currently recommended performance criteria and 2) the outcomes
that can be expected with this procedure.
Study Desing: Studies from 2001 to 2011 on immediate loading with fixed full-arch maxillary prostheses were
reviewed. Clinical series with at least 5 patients and 12 months of follow-up were included. Case reports, studies
with missing data and repeatedly published studies were excluded. In each study the following was assessed: type
of study, implant type, number of patients, number of implants, number of implants per patient, use of post-extrac
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tion implants, minimum implant length and diameter, type of prosthesis, time until loading, implant survival rate,
prosthesis survival rate, marginal bone loss, complications andmean follow-up time. Criteria for patient selection,
implant primary stability and bone regeneration were also studied.
Results: Thirteen studies were included, reporting a total of 2484 immediately loaded implants in 365 patients.
Currently accepted performance criteria regarding patient and implant selection, and surgical and prosthetic pro
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cedures were deduced from the reviewed articles. Implant survival rates went from 87.5% to 100%, prosthesis
survival rates from 93.8% to 100% and radiographic marginal bone loss from 0.8 mm to 1.6 mm.No intraoperative
complications and only minor prosthetic complications were reported.
Conclusions: The literature on immediate loading with fixed full-arch prostheses in the maxilla shows that a
successful outcome can be expected if adequate criteria are used to evaluate the patient, choose the implant and
perform the surgical and prosthetic treatment. Lack of homogeneity within studies limits the relevance of the con
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clusions that can be drawn, and more controlled randomized studies are necessary to enable comparison between
the immediate and the conventional loading procedures
Maxillary sinus lift performed using ultrasound. Evaluation of 21 patients
Purpose: The aim of the present study was to evaluate the sinus membrane perforations that occurred during a sinus lift procedure using the ultrasound technique, and to evaluate the bone gain obtained. Materials and methods: In 21 patients, 26 sinus lifts were performed using ultrasound and filled with bone graft material. The bone height and the bone gain obtained were observed in postoperative orthopantomographs, correcting for previous distortion. Results: Of the 26 maxillary sinus lifts, 4 Schneiderian membrane perforations were observed. The average bone height prior to the intervention was 3.5 mm (scale 0.6- 8.7 mm ) and the average postsurgical bone height was 10.8 mm (scale 7.5- 15.6 mm). An average bone gain of 7.2 mm was observed (range 2.5- 11.7 mm). Conclusions: Based on the results of this study, during ultrasound sinus lift, few Schneiderian membrane perforations occurred and all were small
Dental implants with versus without peri-implant bone defects treated with guided bone regeneration
Background: The guided bone regeneration (GBR) technique is highly successful for the treatment of peri-implant
bone defects. The aim was to determine whether or not implants associated with GBR due to peri-implant defects
show the same survival and success rates as implants placed in native bone without defects.
Material and Methods: Patients with a minimum of two submerged dental implants: one suffering a dehiscence or
fenestration defect during placement and undergoing simultaneous guided bone regeneration (test group), versus
the other entirely surrounded by bone (control group) were treated and monitored annually for three years. Complications with the healing procedure, implant survival, implant success and peri-implant marginal bone loss were
assessed. Statistical analysis was performed with non-parametric tests setting an alpha value of 0.05.
Results: Seventy-two patients and 326 implants were included (142 test, 184 control). One hundred and twenty-five
dehiscences (average height 1.92±1.11) and 18 fenestrations (average height 3.34±2.16) were treated. At 3 years
post-loading, implant survival rates were 95.7% (test) and 97.3% (control) and implant success rates were 93.6%
and 96.2%, respectively. Mean marginal bone loss was 0.54 (SD 0.26 mm) for the test group and 0.43 (SD 0.22
mm) for the control group. No statistically significant differences between both groups were found.
Conclusions: Within the limits of this study, implants with peri-implant defects treated with guided bone regeneration exhibited similar survival and success rates and peri-implant marginal bone loss to implants without those
defects. Large-scale randomized controlled studies with longer follow-ups involving the assessment of esthetic
parameters and hard and soft peri-implant tissue stability are neede
Post-traumatic trigeminal neuropathy. A study of 63 cases
Introduction. Trigeminal neuropathy is most often secondary to trauma. The present study explores the underlying causes and the factors that influence recovery. Material and methods. A retrospective case study was made involving 63 patients with trigeminal neuropathy of traumatologic origin, subjected to follow-up for at least 12 months. Results. Fifty-four percent of all cases were diagnosed after mandibular third molar surgery. In 37 and 19 patients the sensory defect was located in the territory innervated by the mental and lingual nerve, respectively. Pain was reported in 57% of the cases, and particularly among the older patients. Regarding patient disability, quality of life was not affected in three cases, while mild alterations were recorded in 25 subjects and severe alterations in 8. Partial or complete recovery was observed in 25 cases after 6 months, and in 32 after one year. There were few recoveries after this period of time. Recovery proved faster in the youngest patients, who moreover were the individuals with the least pain. Conclusion. Our patients with trigeminal neuropathy recovered particularly in the first 6 months and up to one year after injury. The older patients more often suffered pain associated to the sensory defect. On the other hand, their discomfort was more intense, and the patients with most pain and the poorest clinical scores also showed a comparatively poorer course. © Medicina Oral
Marginal bone loss in relation to platform switching implant insertion depth: an update
A review is made, analyzing marginal bone loss in relation to the depth of implant insertion with platform switching,
according to the position of the neck (supracrestal, crestal or subcrestal), and evaluating survival of the implants.
A PubMed search was made of the studies in animals and humans published between 2005 and 2011, specifying
platform insertion depth (supracrestal, crestal or subcrestal) and registering marginal bone loss from the time of
prosthetic restoration to the end of follow-up (minimum 6 months). A total of 30 studies were included.
The bone loss associated with implants placed at supracrestal level was slightly smaller than in the case of implants
placed at subcrestal level, though statistical significance was not reached. The mean marginal bone loss values were
0.0 mm to 0.9±0.4 mm for the implants with the neck located at supracrestal level; 0.05 mm to 1.40±0.50 mm for
those at subcrestal level; and 0.26±0.22 mm to 1.8±0.39 mm for those in a crestal location, after 6-60 months of
follow-up. The survival rate was 88.6-100% for the implants with the neck positioned at crestal level, versus 98.3-
100% below the crest, and 100% above the crest. The heterogeneity of the studies (surgical technique, platform
surface texture, radiographic measurement techniques, etc.) made it difficult to establish a relationship between
marginal bone loss and the supracrestal, crestal or subcrestal location of platform switching
The outcome of intraoral onlay block bone grafts on alveolar ridge augmentations: a systematic review
Aim: The purpose of this study was to systematically review clinical studies examining the survival and success
rates of implants placed with intraoral onlay autogenous bone grafts to answer the following question: do ridge
augmentations procedures with intraoral onlay block bone grafts in conjunction with or prior to implant placement
influence implant outcome when compared with a control group (guided bone regeneration, alveolar distraction,
native bone or short dental implants.)?
Material and Method: An electronic data banks and hand searching were used to find relevant articles on vertical
and lateral augmentation procedures performed with intraoral onlay block bone grafts for dental implant therapy
published up to October 2013. Publications in English, on human subjects, with a controlled study design –involv-
ing at least one group with defects treated with intraoral onlay block bone grafts, more than five patients and a
minimum follow-up of 12 months after prosthetic loading were included. Two reviewers extracted the data.
Results: A total of 6 studies met the inclusion criteria: 4 studies on horizontal augmentation and 2 studies on
vertical augmentation. Intraoperative complications were not reported. Most common postsurgical complications
included mainly mucosal dehiscences (4 studies), bone graft or membrane exposures (3 studies), complete failures
of block grafts (2 studies) and neurosensory alterations (4 studies). For lateral augmentation procedures, implant
survival rates ranged from 96.9% to 100%, while for vertical augmentation they ranged from 89.5% to 100%.
None article studied the soft tissues healing.
Conclusions: Survival and success rates of implants placed in horizontally and vertically resorbed edentulous
ridges reconstructed with block bone grafts are similar to those of implants placed in native bone, in distracted
sites or with guided bone regeneration. More surgical challenges and morbidity arise from vertical augmentations,
thus short implants may be a feasible optio
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