Clinical and Radiographic Evaluation of Crestal Bone Loss Around Implant With or Without Platform Switching Design
Condition: Crestal Bone Loss
MeSH terms: Bone Diseases, Metabolic
Study type: Interventional
Phase: Phase 2

Summary: 
      Implants have become the preferred method of single tooth replacement these days, patients
      receiving implant treatments not only expect restoration of masticatory function, they also
      expect that the prostheses will be esthetically pleasing, easy to clean, and permanent. To
      maintain long-term implant stability, it is important to minimize bone loss around the
      implant, as well as the soft tissue atrophy that accompanies it.
    

Detailed description: 
      The peri-implant bone level has been used as one of the criteria to assess the success of
      dental implants, Platform switching (PLS) for maintaining peri-implant bone levels has gained
      popularity among implant manufacturers over the last few years. However, the assumption that
      the inward shifting of the implant- abutment junction may preserve crestal bone was primarily
      based on serendipitous finding rather than scientific evidence.

      It is known that saucerization around an implant occurs following abutment connection using a
      submerged implant with a butt joint (a two-stage approach), such as the Branemark implant.
      The nature of saucerization varies according to implant type (one-stage or two-stage) and
      abutment connection type. they have reported that the factors that are the most likely causes
      of early crestal bone loss around implants are:

        1. The micro-gap,

        2. The implant crest module,

        3. Occlusal overload, and

        4. The biologic width around the dental implant. At the Toronto Conference 1998, the
           consensus with respect to bone loss around the implant was that bone loss of up to
           approximately 2 mm during the first year of implant function is acceptable, and at this
           level the implant is regarded as successful. There have been many reports on studies to
           ascertain the causes of bone loss around implants and clinical techniques to prevent it.
           Some reports published in 2005 and 2006 state that the platform switching technique, a
           technique in which an abutment that is one-size smaller than the implant platform is
           placed, prevents bone loss around the implant. However, there are only a few reports on
           the mechanism of action or the extent of bone loss prevention, and as such, it is
           difficult to say that the effect of PLS has been thoroughly examined. This review
           article examines the PLS technique and the bone loss preventive effect.

      A lot of clinical studies discussed the concept of platform switching was extensively studied
      histologically and biomechanically. In histomorphometric studies in dogs was no significant
      difference in the marginal bone level around platform- switched and -matched implants after
      28 days of healing. In contrast, other studies reported a significantly less bone loss around
      platform-switched implants after a loading period of 2 to 6months.

      However, there is no consistency among the studies with respect to the study design (e.g. the
      location and depth of the implant, and controlled/non-controlled), and as such, it is
      difficult to evaluate all of these studies using the same evaluation method.

      The review and meta-analysis show that platform switching may preserve interimplant bone
      height and soft tissue levels. The degree of marginal bone resorption is inversely related to
      the extent of the implant- abutment mismatch. But still no general agreement to confirm the
      validity of this concept, so Further long-term, well-conducted, randomized controlled studies
      are needed to confirm the validity of this concept.
    

Intervention name(s): Platform Matched Design (Group A); Platform Switching Design (Group B)
Intervention type(s): Procedure; Procedure
Intervention description(s): 10 patients with missing upper posterior teeth will receive dental implant with platform matched design (the patients will receive implant 4.2mm with same abutment diameter 4.2mm); 10 patients with missing upper posterior teeth will receive dental implant with platform switching design(the patients will receive implant 4.2mm with smaller abutment diameter 3.5 mm
Other intervention name(s): group 1; group 2
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: platform switching; dental implant; crestal bone level; implant stability; postoperative complication