1,720,977 research outputs found
Damping factor for monitoring the bone interface at dental implants
No full textThe aim of this study is to investigate whether the damping of osseointegrated implants, as measured quantitatively with the Osstell TM equipment, is related to the fractal dimension of peri-implant bone. Fifty-five maxillary implants in function for 3 years before the present study were investigated. Two OsstellTM measurements were obtained for each implant with the transducer oriented first palatally and then distally. Using the half-power bandwidth method, the damping was calculated from the frequency/amplitude plot obtained from the OsstellTM. Damping data were then related to the fractal dimension of peri-implant bone. Fractal dimensions were calculated using a box-counting algorithm on digitally processed intra-oral radiographs of the implants. A Spearman's test was used to verify the correlation between damping and fractal dimension values. All the implants were clinically stable and free from symptoms. The mean ISQ was 63 for the palatal orientation and 71 for the distal orientation. The mean fractal dimension was 1.47; the mean damping value for palatal orientation was 12.3%, while that for the distal orientation was 8.2%. No significant correlation was found. Damping values, measured at peri-implant bone, were found not to be related to a radiographic parameter of trabecular bone pattern like the fractal dimension. The clinical implication would be that OsstellTM graphs displaying distinct or more rounded peaks might both indicate a stable implant as long as the associated implant stability quotients are in the range of satisfactory values proposed in the literature
Edentulia completa del mascellare superiore. Indagine clinico strumentale per la determinazione del corretto tempo di carico implantare permanente.
No full textCorrelation of radiographic fractal analysis with implant insertion torque in a rabbit trabecular bone model
No full textPURPOSE: Insertion torque and resonance frequency analysis are currently used to assess the initial biomechanical competence of an implant. It would be advantageous to have this information during treatment planning. Therefore, the aim of this study was to assess the correlation between a descriptor of bone architecture, namely the fractal analysis of plain radiographs, and implant insertion torque and resonance frequency.
MATERIALS AND METHODS: Sixteen femoral condyles from adult rabbits were subjected to conventional radiography and then received an implant each. The final insertion torque and resonance frequency were recorded for each implant. The fractal dimension of the bone area corresponding to the osteotomy was calculated using a box-counting algorithm. The Spearman test was used to evaluate the correlation between the variables examined.
RESULTS: A linear correlation was observed between fractal dimensions and insertion torque values (rs = 0.704; P = .007). No correlation resulted between fractal dimension and resonance frequency. In addition, a receiver operating characteristic analysis defined a fractal dimension breakpoint of 1.83 to detect soft bone quality, as defined by insertion torque values, with a sensitivity of 80%.
CONCLUSIONS: Given its correlation with insertion torque, the box-counting fractal dimension could be useful to evaluate bone quality at implant sites preoperatively and noninvasively. Further studies are needed to confirm the same accuracy for human bone
One-year outcome of implants strategically placed in the retrocanine bone triangle.
No full textBACKGROUND:
Implant treatment in the partially edentulous maxilla is often challenging because of minimum bone volumes in distal direction.
PURPOSE:
The aim of this study was to evaluate, after 1 year of loading, the outcome of three-unit fixed partial dentures supported by two implants in the retrocanine triangle.
MATERIALS AND METHODS:
Twenty patients with atrophic posterior maxillae participated in the study. A total of 40 implants were placed in residual bone anterior to the sinus wall and posterior to the canine. Implant angulations and lengths were chosen to match as much as possible boundaries of the available bone. After a 6-month healing period, three-unit, screw-retained, fixed partial dentures were delivered. The patients were clinically and radiographically reexamined after 1 year of loading.
RESULTS:
All the implants survived at the end of the follow-up. No differences in bone level changes resulted between axial and tilted implants. No biological or mechanical complications were recorded.
CONCLUSIONS:
Within the limitations of this short-term study on relatively few patients, a positive outcome was seen for three-unit fixed partial dentures supported by two implants. Retrocanine placement of implants with carefully planned lengths and angulations might be an alternative to grafting procedures for restoration of atrophic posterior maxillae
Evaluation of Glyde File Prep in combination with sodium hypochlorite as a root canal irrigant.
No full textThe purpose of this study using a scanning electron microscope was to investigate the efficacy of four different irrigation techniques after canal preparation with Profile Ni-Ti rotary instruments. A modified technique for the use of Glyde File Prep is proposed. Forty anterior teeth were divided into four groups, instrumented, and irrigated as follows: physiological solution (group A), 2.5% sodium hypochlorite (group B), 2.5% sodium hypochlorite and Glyde File Prep (group C), and 2.5% sodium hypochlorite and Glyde File Prep applied at the end of the preparation with sterile paper points (group D). After scanning electron microscopic evaluation at three different levels, debris, smear layer, and dentinal tubules were scored. Groups A and B had significantly more smear layer and less open tubules on the canal walls compared with the group C and group D samples. Differences in the mean amount of debris between group A samples and other irrigation regimes were statistically significant. Copyright © 2002 by The American Association of Endodontists
One-year outcome of narrow diameter blasted implants for rehabilitation of maxillas with knife-edge resorption
No full textOBJECTIVES: This study aimed at assessing the clinical outcome of narrow diameter implants in the treatment of knife-edge edentulous maxillas of adequate bone height but inadequate width (class IV of Cawood and Howell).
MATERIAL AND METHODS: Twelve consecutive patients (eight women and four men, mean age 58 years) with class IV atrophic edentulous maxillas were included in the study. Seventy-three microthreaded TiO(2)-blasted implants were placed and the resonance frequency measured. All the implants had a diameter of 3.5 mm. After 6 months of submerged healing, fixed implant-supported prostheses were delivered to the patients and resonance frequency and radiographic examinations performed. After the first year of loading, the implant outcome was again evaluated clinically, radiographically and with resonance frequency analysis.
RESULTS: All the implants were followed up to 1 year of loading and their survival rate was 100%. Bone loss after 1 year of loading was (mean+/-SD) 0.30+/-0.13 mm. Stability values were (mean+/-SD) 63+/-5.8 ISQ at placement, 60+/-4.7 ISQ at the abutment connection and 61+/-5 ISQ after 1 year of loading. A significant difference resulted between placement and abutment connection values (P=0.03).
CONCLUSIONS: According to the present study, narrow implants may be used to restore edentulous maxillas with atrophies of class IV of Cawood and Howell. When planning the treatment of edentulous maxillas with such a resorption pattern, this possibility has to be considered as an alternative to more demanding grafting techniques
Measurement of enamel thickness in relation to reduction for etched laminate veneers
No full textThe etched porcelain laminate veneer is a new conservative treatment that offers a solution to fractured, discolored, and worn anterior teeth. Preparation of enamel should be 0.5 mm to give minimal porcelain thickness and to avoid an overcontoured restoration. At the same time, dentinal exposure is contraindicated, because resin bonds better with enamel than with dentin. One hundred fourteen extracted teeth were measured at the gingival, middle, and incisal thirds. The resulting data reported on labial enamel thickness of anterior teeth may offer guidance in the preparation of laminate veneers
An eleven-year case report of an avulsed maxillary central incisor after delayed replantation
No full textA 12 year-old girl presented with an avulsed maxillary central incisor for a trauma occurred two days earlier. The avulsed tooth was endodontically treated and replanted. Regardless of the ankylosis and replacement root resorption the tooth was retained for a very favourable nine-year period after trauma. In addition no severe infraposition occurred. When the extraction was necessary, despite the slight atrophy, as a result of compromised alveolar bone development due to ankylosis, an implant-supported crown was placed as definitive rehabilitation without recourse to bone augmentation procedures. In conclusion, delayed replantation in children will require long-term therapeutic commitment. In favourable cases, tooth with delayed replantation might be retained for a very long time thus avoiding the bone atrophy that would have accompanied early tooth loss and, consequently, reducing grafting requirements when a definitive implant-supported restoration will be required
Clinical and Histologic Evaluation of an Active "Implant Periapical Lesion" A Case Report
No full textA new entity called "implant periapical lesion" has recently been described. This lesion could be the result of, for example, bone overheating, implant overloading, presence of a preexisting infection or residual root fragments and foreign bodies in the bone, contamination of the implant, or implant placement in an infected maxillary sinus. This case report describes a titanium implant that was placed in the maxillary premolar region. A fenestration involving the middle portion of the implant was present. After 7 months, the apical portion of the implant showed radiolucency. This lesion rapidly increased in size and a vestibular fistula appeared. A systemic course of antibiotics was not successful, and the implant was then removed. The histologic examination showed the presence of necrotic bone inside the antirotational hole of the implant. The etiology of the implant failure in this instance could possibly be related to bone overheating associated with an excessive tightening of the implant and compression of the bone chips inside the apical hole, producing subsequent necrosis
Use of short implants for functional restoration of the mandible after giant cell tumor removal. Case report.
No full textThe giant cell tumor of the jaws is a rare benign lesion, it has a slow and progressive evolution and it is locally aggressive. Its etiopathogenesis is unknown, it is most common in the mandible and it is often asymptomatic but pain arises from palpation of the area. Diagnosis is made by radiological and histological examination and surgical treatment is necessary. The clinical case of a 28-year-old man affected by a giant cell tumor of the mandible with an aggressive clinical and radiographical behaviour is reported. The patient showed a jaw swelling covered by hyperemic fibro-mucous tissue from tooth 4.6 to 3.4, absence of cortical bone and mobility of teeth. He also reported lip anesthesia. The giant cell tumor diagnosis was made with orthopantomography (OPT), computed tomography (CT) and needle biopsy. The lesion was surgically removed and histological examination confirmed the diagnosis. In spite of the wide loss of bony substance after surgery, the patient was provided with an implant supported fixed prosthesis without previous bone graft. In this case short implants allowed the prosthetic rehabilitation of a mandible with severe ''resorption'' due to surgical removal of a tumor. Implants were placed in the residual bone volume and successfully used to support a fixed prosthesis. The final result is optimal as is the quality of life of the young patient
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