Scientifica implantology

Journal of Oral Rehabilitation, 2014; 41:700-708

This literature review aimed to verify if the platform switching technique effectively reduces peri-implant bone loss. The analysis concluded that not only the presence of platform switching but also of other factors, play a role in the preservation of hard tissue levels, such as the design of the coronal emergence of the implant, its three-dimensional placement with respect to the crest, the type of prosthesis applied, initial bone thickness and the primary stability of the fixture.

Clinical Oral Implant Research, 2013; [Epub ahead of print]

A four-month histological study was performed on experimental implants with a revisited concept of Platform Switching compared to conventional implants. The results showed better preservation of the buccal and lingual bone for implants with platform switching.

European Journal of Oral Implantology, 2010 Winter;3(4):285-96

These clinical studies verified in 32 patients that the “one abutment-one time” concept used for rehabilitating single post-extraction implants, combined with the switching platform technique, is functional to the preservation of the peri-implant bone levels.

Medicina Oral Patología Oral Cirugía Bucal. 2011 May 1;16 (3):e400-5

All the studies included in this literature revision showed how the switching platform protocol improved the preservation of bone around the implant.

Med Oral Patol Oral Cir Bucal. 2011 Sep 1;16 (6):e852-6

The aim of this study was to evaluate the biomechanics of the implant-post system in the case of a traditional and switching platform configuration by means of a finite element analysis. With the proper precautions, it can be affirmed that this technology allows bringing the biomechanical events back to a digital model, analysing the distribution of the stress and evaluating any biological repercussions. The higher the definition (number of nodes and elements), the closer to reality the analysis.
In this case, a 3D finite element analysis was conducted after constructing a mesh with 60,000 elements and 100,000 nodes. To make the analysis conditions as real as possible, special attention was placed on the bone definition. This involved drawing both the cortical and medullary component with the different biophysical characteristics (Young module).
Three different implant-post configurations were evaluated:
1. Implant with a diameter of 3.8 mm and corresponding post (Standard control model)
2. Implant with a diameter of 5.5 mm and corresponding post (increased control model)
3. Implant with a diameter of 5.5 mm and 3.8 mm post (experimental model with switching platform configuration).
A Global implant manufactured by Sweden & Martina was used.
In accordance with the literature and the ISO standards which standardise the experimentation conditions, vertical (axial) loads of 130N and horizontal loads of 90N were applied on the crown portion of the post. With these load conditions, the Von Mises stress index was evaluated and the minimum and maximum values were recorded for each implant-post configuration.
At the end of the experimentation, the Von Mises stress levels recorded on the standard configuration induced by the load varied from 150 MPa to 58 Pa (at an implant level) and from 150 Mpa to 52 MPa (at an abutment level); in the configuration of the increased model, the stress levels varied from 45 MPa to 55 Pa (implant) and from 70 MPa to 55 MPa (abutment); in the switching platform configuration, the stress levels measured varied from 190 MPa to 64 Pa (implant) and from 85 MPa to 42 MPa (post). The maximum stress levels transmitted by the implant-post system to the cortical and trabecular bone were respectively 67 Pa and 52 MPa (standard configuration); 54 Pa and 27 MPa (increased configuration) and 64 Pa and 42 MPa (switching platform). An evaluation of the stress levels on the body of the fixture
allowed highlighting a substantial reduction in stress in the threading region, correlated to a diameter difference between the implant and post in the switching platform configuration. In conclusion, it can be affirmed that the switching platform configuration not only leads to a relative reduction in the stress levels compared to standard configurations (both standard and increased), but also to a significant movement in the stress area from the bone to the implant platform, thus potentially generating less overloading of the bone crest.

This mechanical finite element study evaluated the different distribution of the stress levels between implants with a small and large diameter restored with traditional protocol, comparing them with implants restored with reduced abutments according to the switching platform concept. The results demonstrated that the switching platform configuration not only leads to a relative reduction in the stress levels compared to standard narrow and large configurations, but also to a significant movement of the stress area, potentially resulting in less overloading of the bone crest.

Clinical Oral Implant Research, Early View First Published online on 2011, November 2nd

The switching platform technique with a mismatching of 0.85 mm can maintain the bone level of the buccal crest better than a traditionally loaded implant.

International Journal of Oral and Maxillofacial Implants, 2011 May-Jun;26(3):618-30

The authors examined the immunohistochemical relationship between the quality of the receiving bone and peri-implant bone reabsorption at 36 months in sites treated with standard protocol versus switching platform protocol. An individual tendency for reabsorption was observed. The individual bone structure and quality at a local level seemed to be correlated to the level of reabsorption, which was also influenced by the presence of biglycans and the tumour necrosis factor-alpha.

Journal of Clinical Periodontology, 2011; 38: 86?94

This histological study in humans analysed the characteristics of soft tissues around the implant at 48 months, and compared implants rehabilitated with the switching platform concept to the traditional prosthetic protocol. The results showed that the switching platform protocol does not alter the soft tissues and that bone peaks are maintained.

Clinical Oral Implant Research 22, 2011; 438?444

This study demonstrated that implants restored according to the switching platform concept with mismatching of 0.25 mm maintained the same level of bone crest as traditional implants if the smooth part of the neck of traditional implants is left to emerge from the bone.

NumeriUno, 1: 6-7, 2008

PLATFORM SWITCHING AND IMMEDIATE SINGLE TOOTH LOADING IN THE AESTHETIC ZONE

Today’s aesthetic requirements force dentists to use immediate rehabilitation procedures in cases of tooth extraction in the front-upper sectors. In these cases, implant treatment is now a valid alternative to traditional fi xed prosthesis because it does not require the preparation of the teeth next to the edentulous site, therefore resulting in greater preservation. Furthermore, immediate loading protocols have contradicted the Brånemark dogma, which requires a 6-month submerged healing period for
implants inserted in type D3 or D4 bone (upper front sectors). Numerous studies have shown that immediate loading has a long-term effi cacy in single-tooth replacement, which forms the basis of the clinical case presented in this article. The report illustrates the implant therapy of a vertical fracture with traumatic aetiology of an element at the same time as the micro-invasive extraction of the tooth, performed by trying to protect the vestibular cortex as much as possible and the mesial and distal bone peaks. For a better aesthetic result, the implant tunnel for inserting the Ø 5.50 mm and 1.13 mm Global prosthesis was prepared, sinking it 3 mm into the basal bone with a torque of 42 Ncm and fi lling the jumping distance with bovine bone matrix mixed with collagen. The alternate use of drills and osteotomes allowed maintaining the vestibular lump preventing the creation of fenestrations or bone defects.
Within 24 hours, a prosthetization was performed with a provisional crown with direct technique using the Platform Switching restoration concept, screwing a fi nal post with a diameter of 3.8 mm to the implant. The patient was re-evaluated after 12 months to check the healing state of the soft tissues and the bone. Clinical and radiographic controls showed no evidence of gingival recession or aesthetic difficulties. The height of the papillae and of the vestibular and oral gingival margin remained constant. Instead, there was an increase in the distal papillae between the mounting of the final prosthesis and the 12-month follow up. The periodontal parameters showed that there was no bleeding on probing and the probing was always below 3 mm. The radiography showed minimal bone reabsorption even
after the 12-month follow up. The ZirTi surface along the entire length of the implant and the coronal micro-grooving seemed to affect the bone maintenance. Therefore, the aesthetic result was as expected and remained constant over time. The elementary surgical and prosthetic technique made it easy to reproduce the method. The micromechanical qualities (ZirTi surface) and the macromechanical qualities of the Global implant make it resistant to micro-movements, which are detrimental for the long-term stability of the bone-implant interface, making it possible to load the fi nal prosthesis after 2 months of insertion. The early interception of the fracture, the presence of a thick gingival biotype, the morphology of the implant platform, the use of the platform-switching concept and the use of a fi nal abutment on the fi rst day of loading are all extremely important conditions for maintaining the bone and gingival architecture in the long term and, consequently, the aesthetics.