The results demonstrated that Straumann implants with the SLActive surface are safe and predictable when used in immediate and early loading procedures. Even in poor-quality bone, survival rates were comparable with those from conventional or delayed loading. The mean bone-level change was not deemed to be clinically significant and compared well with the typical bone resorption observed in conventional implant loading.
The present work focuses on the physicochemical characterization of selected mineral-based biomaterials that are frequently used in dental applications. The selected materials are commercially available as granules from different biological origins: bovine, porcine, and coralline. Natural and calcined human bone were used for comparison purposes. Besides a classical rationalization of chemical composition and crystallinity, a major emphasis was placed on the measurement of various morphostructural properties such as particle size, porosity, density, and specific surface area. Such properties are crucial to acquiring a full interpretation of the in vivo performance. The studied samples exhibited distinct particle sizes (between 200 and 1000 lm) and shapes. Mercury intrusion revealed not only that the total sample porosity varied considerably (33% for OsteoBiol 1 , 50% for PepGen P-15 1 , and 60% for BioOss 1 ) but also that a significant percentage of that porosity corresponded to submicron pores. Biocoral 1 was not analyzed by this technique as it possesses larger pores than those of the porosimeter upper limit. The density values determined for the calcined samples were close to the theoretical values of hydroxyapatite. However, the values for the collagenated samples were lower, in accordance with their lower mineral content. The specific surface areas ranged from less than 1 m 2 /g (Biocoral) up to 60 m 2 /g (BioOss). The chemical and phase composition of most of the samples, the exception being Biocoral (aragonite), were hydroxyapatite based. Nonetheless, the samples exhibited different organic material content as a consequence of the distinct heat treatments that each had received. '
The results suggested that Straumann implants with an SLActive can be used predictably in time-critical (early or immediate) loading treatment protocols when appropriate patient selection criteria are observed. The mean bone level changes observed from baseline to 5 months (0.56 and 0.81 mm) corresponded to physiological observations from other studies, i.e., were not clinically significant. The presence of a significant center effect and treatment x center interaction indicated that the differences in bone level changes between the two groups were center dependent.
ObjectiveThe purpose of this ongoing randomized study was to assess differences in bone level changes and success rates using implants supporting single crowns in the posterior mandible either with platform matched or platform switched abutments.Material and MethodsPatients aged 18 and above, missing at least two teeth in the posterior mandible and with a natural tooth mesial to the most proximal implant site were enrolled. Randomization followed implant placement. Definitive restorations were placed after a minimum transgingival healing period of 8 weeks. Changes in crestal bone level from surgery and loading (baseline) to 12-month post-loading were radiographically measured. Implant survival and success were determined.ResultsSixty-eight patients received 74 implants in the platform switching group and 72 in the other one. The difference of mean marginal bone level change from surgery to 12 months was significant between groups (p < 0.004). Radiographical mean bone gain or no bone loss from loading was noted for 67.1% of the platform switching and 49.2% of the platform matching implants. Implant success rates were 97.3% and 100%, respectively.ConclusionsWithin the same implant system the platform switching concept showed a positive effect on marginal bone levels when compared with restorations with platform matching.
Aim
The aim of this study was to compare clinical and radiographic outcomes of dental implants with different neck characteristics.
Methods
A protocol‐oriented search aimed at the question: “In patients subjected to tooth replacement with screw‐type dental implants does the modification of the implant neck macro‐ or microgeometry contribute to the improvement of survival rates and maintenance of the peri‐implant marginal bone levels?” Primary outcomes were survival and marginal bone level (MBL) changes evaluated on randomized controlled trials with >10 participants and follow‐up >1 year. Risk of bias was evaluated using the Cochrane Collaboration's tool. The review follows the PRISMA statement.
Results
Forty‐three studies compared: (a) One‐ versus two‐piece implants (N = 7); (b) Two‐piece implants with different neck characteristics (machined and rough collars, microthreads, LASER microtexturing) (N = 21); (c) Two‐piece implants with macrogeometry modifications (tapering, back‐tapering, and scalloping) (N = 6). One‐ and two‐piece implants showed similar survival (RR = 0.45, 95% CI: [0.12, 1.66], p = 0.23) and MBL changes (WMD = 0.09 mm, 95% CI: [−0.27, 0.45], p = 0.64) at 1‐year post‐loading. Machined collar implants have higher risk of early failure than rough collar implants (RR = 3.96, 95% CI: [1.12, 13.93], p = 0.03) and 0.43 mm higher bone resorption (95% CI: [0.0, 0.86], p = 0.05). Microthreads (WMD = 0.07 mm, 95% CI: [−0.01, 0.15], p = 0.10) and LASER microtexturing (WMD = 0.15 mm, 95% CI: [−0.35, 0.65], p = 0.56) do not reduce bone resorption. Scalloped implants have 1.26 mm higher resorption (95% CI: [0.72, 2.00], p < 0.001).
Conclusions
One‐ and two‐piece implants have similar survival and MBL changes. Rough collar implants have lower MBL changes than machined collar implants. Additional modifications to rough collars are irrelevant.
Changes in crestal bone level occurred mostly during the first 5 months postloading. After this bone remodeling period, crestal bone level was stable up to 36 months. Implants with a chemically modified surface are safe and predictable for immediate and early loading in the posterior maxilla and mandible.
Two commercial bone grafts used in dentistry (Osteobiol Gen-Os®, a xenograft of porcine origin, and Bonelike®, a hydroxyapatite based synthetic material), in the form of granules, were characterized and evaluated in vivo regarding the intensity of the tissue inflammatory response. These biomaterials were characterized in terms of morphology, particle size distribution, porosity and pore size, specific surface are and density. The chemical composition and structure of the materials were accessed by Fourier-Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD). The graft materials were implanted in the gluteus maximus muscles of Wistar rats and the inflammatory response evaluated through histological analysis, after one week of implantation.The results showed that the two grafts have quite different characteristics in practically all the evaluated properties. While Osteobiol® exhibits a structure and composition similar to the natural bone, Bonelike® is constituted by a main crystalline phase of hydroxyapatite and two secondary phases of -and -tricalcium phosphate. Osteobiol® granules, besides being larger, are irregular, and exhibit sharp-edged tips, while those of Bonelike® are approximately cylindrical, with round contours, and more uniform in size. The in vivo response evaluated from the inflammatory infiltrates revealed that although both implants did not cause severe inflammation, Bonelike® granules elicit a consistently more intense inflammatory reaction than that triggered by the granules of Osteobiol®, particularly in terms of collagen production and formation of fibrous capsule. This reaction was partly explained in terms of the characteristics evaluated for the granules of this material.
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