2,136 research outputs found
Implant-abutment interface:bacterial leakage and microgap formation in two different type of Implant connections
No full textAim
The aim of this study is to evaluate, both in vitro and in vivo, two different types of implant-abutment connections: screwed connection and cemented connection, analyzing the permeability of the IAI to bacterial colonization and the stability to chewing forces.
Materials and Methods
In this study were compared two different types of implant-abutment connections: internal hexagon screwed connection (Winsix®, BioSAF IN, Ancona, Italy ) Group 1; and internal hexagon cemented-conical connection (Bone System®, Milano, Italy) Group 2. Group 1 and Group 2 were compared on three levels: impermeability to bacterial penetration an in vitro study, resistance to loading for 5 years a simulated computer model, type of peri-implant bacterial colonization and health of peri-implant soft tissues around the implant for 2 year in an in vivo study.
Results
The results had showed the lower stability to the screwed implant-abutment connection than the cemented implant-abutment connection both for the permeability to the bacterial colonization than for the stability to the chewing forces.
Conclusion
Also if the implants long-term failures are consequences of multi-factorial elements the choice of an adequate implant system is fundamental for the long-term success. Also the choice of connection system is very important and would be preferable to choose implants with cemented connection instead of implants with screwed connection
Determination of vertical dimension of an implant-supported prosthetic rehabilitation with surface electromyography: case report
No full textDetermination of vertical dimension of an implant-supported prosthetic rehabilitation with surface electromyography: case report.
Abstract
The aim of each prosthetic rehabilitation is to achieve a proper occlusion structurally and functionally integrated in the individual neuromuscolar system.
This is particularly important in implant-supported prosthetic rehabilitation because the main cause of implant failure is the presence of an abnormal forces distribution(1).
The forces acting on a prosthetic rehabilitation are amplified by an incorrect determination of Vertical Dimension(2).
The methods proposed in the literature for the determination of occlusion Vertical Dimension are manifold but at present there is no consensus on the methodology to be used for both the variability of results between different methods, both because no author takes into account the effect that the new Vertical Dimension produces on the neuromuscular individual system(3-5).
The aim of this study is to evaluate the possibility of determining a "individually correct" Vertical Dimension through the use of the Surface Electromyography (sEMG).
For this study was selected one male patient, 55 age old, which needed of an superior overdenture.
Were performed three acquisitions throught the use of the electromyograph*: the first at the time of delivery of provisional prothesis, the second after modify of provisional prosthesis and the third at the delivery of final prosthetic.
The "individually correct" Vertical Dimension was achieved by the modify of provisional prosthetic, following the stabilization of indices indicated by the software**: Temporal POC, Masseter POC, Activity Coefficient, Asymmetry Index, Torque and, above all, Impact..
At the time of delivery of final prosthesis, all the considered indices showed the values in the biological range.
The results obtained show that the use of surface electromyography allows to combine the qualitative information with quantitative measurements, allowing the determination of a individually correct Vertical Dimension.
The use of this tool, therefore, can become part of the prosthetic protocol, guiding the operator through the various phases of the prosthetic rehabilitation. This can certainly influence in positive the success rate of implant, since in a system in neuromuscolar equilibrium the overload components of the implant are reduced. A proper distribution of masticatory loads through the prosthetic system, in conjunction with proper hygiene procedures and appropriate strategies for the preservation, is the best guarantee of long-term survival of each implant-supported prosthetic rehabilitation
Extraction Socket Preservation Using Porcine-Derived Collagen Membrane Alone or Associated with Porcine-Derived Bone. Clinical Results of Randomized Controlled Study
No full textObjectives: The aim of present randomized controlled clinical trial was to clinically evaluate hard tissue changes after extraction socket preservation procedures compared to natural spontaneous healing.
Material and Methods: Thirty patients were enrolled in the present study and underwent single-tooth extraction in the premolar/molar areas. Ten sites were grafted with porcine-derived bone covered by collagen membrane, 10 covered by porcine-derived collagen membrane alone, and 10 underwent natural spontaneous healing. Vertical and horizontal bone changes after 3-month were evaluated at implant placement.
Results: The vertical and horizontal bone changes at the extraction sockets treated with collagen membrane alone (vertical: -0.55 [SD 0.11] mm, and horizontal: -1.21 [SD 0.69] mm) and collagen membrane plus porcine-derived bone (vertical: -0.37 [SD 0.7] mm, and horizontal: -0.91 [SD 0.53] mm) were found significantly lower (P < 0.001), when compared to non-grafted sockets (vertical: -2.09 [SD 0.19] mm, and horizontal: -3.96 [SD 0.87] mm).
In type 1 extraction sockets, in premolar sites, and in presence of vestibular bone thicknesses ≥ 1.5 mm, the use of collagen membrane alone revealed similar outcomes to those with additional graft material.
Conclusions: At the re-entry surgery, extraction sockets grafted with porcine-derived bone and covered by collagen membrane, and extraction sockets covered by porcine-derived collagen membrane alone, showed significantly lower vertical and horizontal bone changes, compared to extraction sockets sites underwent natural spontaneous healing. However, a complete prevention of remodelling is not achievable, irrespective of the technique used
Laser therapy in retrograde peri-implantitis. Case reports.
No full textBackground: The term retrograde peri-implantitis is commonly used to describe lesions in the periapical region of dental implant. It is defined as a clinically symptomatic periapical lesion ( diagnosed as radiolucency) that develops shortly after implant insertion while the coronal portion of the implant achieves a normal osseointegration. Etiologic factors that lead to retrograde peri-implantitis include, inter alia, the presence of a pre-existing inflammation. Information about the incidence and treatment of retrograde peri-implantitis is scarce and mostly collected from some sporadic case reports. The aim of this study is to compare manual debridement versus Er:YAG laser treatment as treatment modalities for retrograde preri-implantitis.
Materials and methods: Two patients, that showed a radiolucency around the most apical part of the implant, were included in this study. Both patients were treated with a surgical procedure. The protocol included elevation of a full-thickness flap, complete removal of granulation tissue with hand instruments and curettage of the bony cavity walls. One of two patients also received treatment with Er:YAG laser. The patients were followed at 1 week, 1 month, 3 months, 6 months and 1 year postoperatively.
Results: A 1-month follow-up, both two patients showed no pain or discomfort. No sign of infection was noted. A 3-months follow-up, the patient, who was treated only with manual debridement, showed a recurrence of the lesion while in the patient, who was treated with Er: YAG laser, was observed further progress of bone healing. The radiographic examinations of the patient who was treated with laser, at 6-months follow-up and at 1-year follow-up, showed increase radiographic bone density and new bone formation at the apical region of the implant. The patient remained asymptomatic.
Discussion: The periapical lesion around the implants is a possible cause for implant failure. Quiryen and colleagues suggest that some of the early failures may be linked with an endodontic pathology remaining after tooth extraction. They also reported an almost three times higher incidence of failure for implants suffering from apical peri-implantitis when a endodontic pathology around previously extracted teeth was present. They also suggested that removal of all granulation tissue was sufficient to prevent further progression of the disease. This study instead shows that the addition of treatment with Er:YAG laser may decrease the risk of lesion recurrence
Predictability of post-extraction immediate load implants: Use of standardized clinical protocols
No full textImplant survival and success rates in patients with risk factors: results from a long-term retrospective study with a 10 to 18 years follow-up
No full textOBJECTIVE:
Risk factors for implant therapy are represented by all general and local conditions that through various mechanisms can increase either short-term and long-term failure risk. The aim of this study is to assess the implant survival and implant success rates with single and multiple risk factors.
PATIENTS AND METHODS:
To address the research purpose, a retrospective cohort study was designed and implemented, including a sample of 225 patients with a total of 871 implants placed. The following risk factors were considered: smoking, bruxism, bone augmentation procedures and the presence of load risk (implants with crown/implant relation > 0.8; angulation > 25°; presence of cantilever). Follow-up ranged from 10 years to 18 years (average follow-up 13.6 years). Failures were subdivided into short-term failures, before the prosthetic phase, and long-term failures, after definitive prosthesis. The success criteria published by Albrektsson and Zarb were adopted. A Cox proportional hazard regression model was used to calculate hazard ratio, with a statistically significant p-value <0.05.
RESULTS:
Out of the 871 implants placed, 138 did not meet the success criteria, (success rate 84.16%), sixty (43.47%) were classified as "early failure" and seventy-eight as "late failure" (56.53%). A total of 70 dental implants were removed, with a survival rate of 91.96%.
CONCLUSIONS:
The presence of a single risk factor does not imply a marked increase of failure risk. Among the analyzed factors, the one that proved to be the most dangerous was bruxism, even when presented as the only risk factor. Bruxism with load risk proved to be the most dangerous association (success rate 69.23%) and could be included among the absolute contraindications for implant treatment
A randomized clinical trial about presence of pathogenic microflora and risk of peri-implantitis: comparison of two different types of implant-abutment connections
No full textOBJECTIVE:
The aim of this in vivo study was to evaluate two different types of implant-abutment connections: screwed connection and cemented connection, analyzing peri-implant bacteria microflora as well as other clinical parameters.
PATIENTS AND METHODS:
Twenty implants were selected, inserted in 20 patients, 10 with a screwed implant-abutment connection (Group 1) and 10 with a cemented implant-abutment connection (Group 2). The peri-implant microflora was collected, after at least 360 days from the prosthetic rehabilitation, using paper points inserted in peri-implant sulcus for 30 s. Polymerase chain reaction (PCR) Real-time analyzed the presence of 9 bacteria periodontal-pathogens and Candida albicans.
RESULTS:
Our findings showed that bacteria colonized all Groups analyzed, the average bacterial count was 3.7 E +08 (±1.19) in Group 1, compared to 2.1 E +08 (±0.16) in Group 2; no statistically significant differences were observed (p>0.0.5). In Group 1, however, bacterial colonization of peri-implant sulci was over the pathogenic threshold for 5 bacteria, indicating a high-risk of peri-implantitis. Also in Group 2, results showed a microflora composed by all bacteria analyzed but, in this case, bacterial colonization of peri-implant sulci was over the pathogenic threshold for only 1 bacterium, indicating a lower risk of peri-implantitis. Moreover, clinical parameters (PPD > 3 mm and m SBI > 0) confirmed a greater risk of peri-implantitis in Group 1 compared to Group 2 (p<0.05).
CONCLUSIONS:
We concluded that, also after only 360 days, implants with screwed connection showed a higher risk of peri-implantitis that implants with cemented connection
- …
