A full-thickness mucoperiosteal flap was elevated to expose the underlying alveolar bone and allow implant placement in the correct prosthetically driven position. The inter-implant distance was at least 3 mm, while an interproximal space of 1. The implants were positioned in the bleeding socket with hand pressure and driven to their final position using a dedicated mounter at 60 rpm.
The implants were all placed 0. A torque value between 30 and 60 Nm was accepted, depending on the bone density. The repositioned mucoperiosteal flap was then secured with a tension-free suture for primary healing and to avoid bacterial contamination. All of the implants were placed in native crestal bone. No implant was located in a regenerated or post-extractive site. All patients observed a day liquid diet, plus 15 days of soft foods following the implant placement.
Oral hygiene included the modified Bass brushing technique and s 0. The patients were recommended not to use removable partial dentures that may apply pressure over the surgery site.
In some cases, an adhesive provisional Maryland bridge was applied, taking care not to touch the tissue over the implant. The osteointegration time was set at three months for the mandibular implants and six months for the maxillary implants.
During the second-stage surgery, a mid-crestal mesiodistal flap was cut to ensure displacement of the keratinized tissue. The cover screw was manually unscrewed using a dedicated screwdriver and then replaced with a healing abutment. An initial impression was taken using alginate Hydrogum5, Zhermack, Rovigo, Italy to create an individualized impression tray. A second impression using polyether Impregum TM , 3M Italia Srl, Milan, Italy was then taken using the individualized open tray for a pick-up technique.
Using a randomization table, the implants were assigned to either the PS group example in Figure 2 or the NPS group example in Figure 3 and the appropriate type of prosthodontics was then requested from the technician. A provisional screw-retained crown A is set in place in Section 2.
After three months, the emergence profile is transferred to the technician through the individualized transfer technique B to reproduce the same emergence profile of the provisional in the final crown. The PS final rehabilitation C is delivered. After three years the crown shows acceptable integration D and good stability of the buccal gingival zenith. On the right E the X-ray is acquired at the time of the final crown delivery. In the edentulous ridge A is placed an implant in Section 2.
Six months later, the second stage surgery B is performed through a mid-crestal flap for the minimal displacement of the keratinized tissue and a provisional screw-retained crown C is set in place.
Three months later the NPS final rehabilitation is delivered. On the right E is the three years X-ray. A resin screw-retained provisional prosthesis was delivered two weeks after the second-stage surgery. The provisional prosthesis was removed after three months and another impression was taken to manufacture the definitive metal-ceramic prosthesis according to the group assignment. All of the rehabilitations were cemented on milled standard abutments providing for a juxta-gingival emergence profile.
Meanwhile, the rehabilitation for the NPS group used an internal flat-to-flat abutment connection with a matching platform no PS abutment. The occlusion was checked to remove pre-contacts and all interferences in centric, lateral, and protrusive movements. The definitive rehabilitations included both single crowns and partial fixed prostheses, up to a maximum of four elements.
A database was created to collect and process all of the implant and patient information. Patient anamnestic data were collected from the clinical exam and anamnesis. Intraoral radiographs were used to evaluate the implants at the time of implant placement, when delivering the provisional and final crowns, and at the yearly follow-up appointments after the final rehabilitation.
The implant depth Figure 4 was determined based on a periapical radiograph at the time of the implant placement and recorded as the average distance from the implant shoulder to the first radiographic bone-to-implant contact FBIC. FBIC first bone to implant contact measure on a periapical radiograph left and the schematic detail right.
After delivering the definitive crown, the presence of keratinized facial mucosa was checked and the prosthetic crown height TH was quantified Figure 5.
The TH was measured as the distance between the buccal gingival margin at the zenith and the crown incisal edge according to the main axis of the crown itself Figure 5. In more detail, the TH was quantified directly in the mouth, observing the tooth perpendicularly to its facial surface. In the case of doubt, a second observer repeated the measure and an average dimension was registered.
The baseline value was set at the time of the definitive prosthesis delivery, and the measurement was then repeated at one, two, and three years of follow-up from the final crown delivery. TH measurement through the probe. The requested sequence was one set of 90 balanced integer numbers with no sorting, ranging between 0 and 1, respectively associated with the NPS and the PS group.
The assignment was consecutively associated with the implants, following the random set. A descriptive analysis was produced for the consecutively enrolled implants. The total follow-up time was three years from the time of the definitive prosthesis delivery, which occurred three to six months from the provisional prosthetic positioning. The TH baseline was determined at the time of the definitive crown delivery and the follow-up values were measured at one, two, and three years after.
The implants were divided into two groups according to the presence of platform-switching PS group or no-platform-switching NPS group. The delta was measured by subtracting the follow-up TH value from the baseline TH. Consequently, positive values were associated with soft tissue recession, while negative values were related to coronal gingiva repositioning, referred to as definitive prosthodontic rehabilitation.
Hence, recession was identified when the free buccal gingival margin measured at the zenith shifted apically. Meanwhile, gingival growth was associated with a coronal soft tissue migration of the gum. As the distribution was supposed to be normal, a two sample two-tail t -test was applied.
A sample size of 39 subjects per group was used in order to detect a 0. Significance level and required power analysis were derived from previous literature [ 20 , 21 , 22 , 23 , 24 , 25 ].
At the end of the data gathering period, a Shapiro—Wilk test for normality was used to assess the sample distribution. Where the null hypotheses were rejected, the samples were evaluated as non-normally distributed and a Mann—Whitney test was applied to the independent samples. A total of 90 implants were placed according to the standardized surgical and prosthetic protocols fixed at the beginning of the prospective study.
Among the 90 implants enrolled in the study, 77 implants were finally considered in the statistical analysis. The drop-out implants were: two due to missing radiographs during the treatment; nine belonging to patients who were unable to attend the follow-up, were no longer contactable, or moved to a different city; and two that presented signs of mucositis during the observation period.
All of the implants AnyRidge, MegaGen, Seoul, Korea provided a flat-to-flat connection with the same-brand abutment and were placed in both the anterior and posterior region, and the upper and lower jaw. The implant distribution is reported in Table 1 and Table 2.
The peri-implant bone with straight and angulated abutments. Another possible explanation of the abutments. Influence of Platform Switching on Various Factors Bone stability is an important factor in evaluation of affecting crestal bone loss around implants.
Resorption of bone in marginal areas can effect of platform switching on crestal bone loss at non change the surrounding soft tissue profile which can www.
Thus a close proximity of the phonetic changes and food impaction. There are many IAJ to the bone, which is always established factors responsible for influencing the marginal bone loss when implants are placed epicrestally, is including the dental implant connection type. An internal repositioning of the IAJ According to Rodrigo et al [21] osseo integrated implants by platform switching may decrease the effect of with internal connections showed less marginal bone loss ICT and as a result may decrease bone loss.
This is mainly due to presence of platform switching present in The effect of platform switching on marginal bone level internal connection implants. This is because in platform seemed to be dose dependent, i. There is a strong tendency that around two or more concentration, decreased micromovements, and also the adjacent platform switched implants peri implant bone is bacterial colonization takes place at a farther region of better preserved.
The influence on inter implant distance bone. Apico coronal position of implants in relation to crestal bone. This review concluded that the The presence of the soft tissue above the bone is more deeper the implant is placed the more bone explained as a defense mechanism — a sort of barrier or loss will occur.
Presence of various implant microtextures. The from the bacterial invasion of oral cavity. This seal is merely the biologic width that is present on 3. The degree of platform switch. The effect of the natural tooth surface and in a similar way on implants degree of platform switching on marginal bone exposed to oral cavity.
The thickness of this mucosal seal loss is inversely related i. Reliability of examination methods. A three dimensional examination method is more Inflammatory cells were detected in clinically healthy reliable as compared to a two dimensional peri gingival and perimplant mucosa as well as peri implant apical radiograph.
In clinically healthy Effect of platform switching on hard and soft tissues: gingiva and peri implant tissues, mostly T lymphocytes were found in a narrow area of connective tissue lateral Platform switching demonstrates less vertical change in to JE. In the inflamed peri implant tissues B cells the crestal bone heights around implants than expected.
At the histological evaluation There is a good soft tissue healing and maintenance of platform switching, it reduces the inflammatory infiltrate papillae and buccal margin levels were consistently at the IAJ. PS implants behave better than NPS implants, regarding soft and hard tissue maintenance.
In healthy peri implant connective tissue, collagen fibers were well organized and generally are homogeneous. Two main reasons for the reduced bone loss around However in inflamed peri implant tissue the collagen platform switched implants: fibers are loosely packed, thin fibrils, disorganized and not well arranged, impairing the structural resistance of 1.
Shifting of the stress concentration area away soft tissue to bacterial penetration. Mismatching seems to from the cervical bone- implant surface to lead to the establishment of a wider and more resistant ensure less micro movement in the adjacent zone of connective tissue at level of implant abutment bone structure. It shifts the inevitable microgap of the IAJ away from the outer edge of the implant and The fibers that are perpendicular to the implant change neighboring bone.
The IAJ is always encircled their direction and arrange themselves in a circular way by an inflammatory cell infiltrate ICT when they meet the implant surface. In PS implants this 0. The von mises The use of PS implants may help to minimize the stresses in the abutment of platform switched models perimplnat bone loss and consequently alterations on were lower [28] than the abutment of conventional adjacent soft tissues, associated to the correct surgical and models.
The reduction of stresses in in the abutment with prosthetic planning ensuring excellent esthetics and platform switching versus the conventional abutment was function [25].
Specifically by coupling platform switching to abutment emergence profile modification, clinicians will create Stress Analysis by Photoelastic Method [6]: more space around implant abutment interface to allow for the development of additional soft tissue volume, Photoelasticity allows prediction of the mechanical better control of gingival margin and good oral hygiene response of photoelastic model when load is applied.
The maintenance. Evaluation of peri-implant bone loss around platform-switched implants. Prospective clinical evaluation of Morse taper connection implants: Results after 4 years of functional loading. Clin Oral Impl Res ; Biomechanical repercussions of bone resorption related to biologic width: A finite element analysis of three implant-abutment configurations.
Canullo L, Rasperini G. Preservation of peri-implant soft and hard tissues using platform switching of implants placed in immediate extraction sockets: A proof-of-concept study with to month follow-up.
Int J Oral Maxillofac Implant ; Immediate maxillary restoration of single-tooth implants using platform switching for crestal bone preservation: A month study. Int J Oral Maxillofac Implants ; The effects of interimplant distances on papilla formation and crestal resorption in implants with a morse cone connection and a platform switch: A histomorphometric study in dogs.
Influence of 3-D bone to implant relationship on esthetics. Int J Periodontics Restorative Dent ; This article has been cited by. Peri-implant bone level around implants with platform-switched abutments. Journal of Clinical Periodontology. Romanos GE, Javed F. Platform switching minimises crestal bone loss around dental implants: truth or myth?
Journal of Oral Rehabilitation. Implant platform switching concept: a literature review. Eur Rev Med Pharmacol Sci. Lustbader D. Nobel Biocare. Popular, well-proven concept. Clin Implant Dent Relat Res, 16 2 , —
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