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Title Platform Switching is Ineffective in Perserving Marginal Bone
Clinical Question Does Platform switching concept using different implant/abutment mismatching alter the marginal bone level long term?
Clinical Bottom Line There appears to be no long-term advantage of the platform switching concept over traditionally restored implants when comparing marginal bone levels. (See Comments on the CAT below)
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 24158333 Enkling/201325 patients receiving 2 implants in the posterior edentulous mandible.Randomized Split-mouth Design
Key resultsTwo neighboring implants with a diameter of 4 mm and a length of 9.5 mm were placed with the implant platform at bone level by raising a full thickness flap. The minimum inter-implant distance was defined as 4 mm and the minimum distance between implant and neighboring tooth, as 2 mm. The allocation of the platform-switching and standard platform implants was randomized by means of a computer-generated list before surgery. The size of platform switching (i.e., the circular step) was 0.35 mm: implant shoulder diameter = 4.0 mm vs. abutment diameter at platform = 3.3 mm. After 3 months of submerged healing, implants were reopened, and after 4 months, crowns were cemented on the implants, one with standard platform and one with platform switching. Oral Hygiene was strictly monitored by full-mouth sulcular bleeding index, full-mouth plaque index, and peri-implant probing depth: baseline, reopening (3 months), crown mounting (4 months), and at check-ups of 8, 12, 25 and 38 months. All patients were available for all follow up examinations. After 3 years, the implant survival rate was 100%. The mean intra individual difference in bone loss between platform switched and standard platform was 0.05 ± 0.58 mm (95% confidence interval: –0.19, 0.29). Crestal bone-level alteration depended on time (p < .001) but not on platform type (p = .363). Thus, limited vertical bone loss was observed regardless if a platform switching or a standard-platform concept was applied. The hypothesis of bone resorption–preventing effect of platform switching could not be confirmed, and treatment can be chosen according to the preferences of the clinician.
Evidence Search The following search strategy used in Pub Med: bone loss, dental implants, platform switching
Comments on
The Evidence
There was a large sample of implants restored with platform switching concept using different implant/abutment mismatching. The study represented the full spectrum of possible outcomes for patients who have been restored with this concept. The criteria for each diagnosis were explicit and credible. The diagnostic work up was comprehensive and consistently applied. All the patients were in general good health and were followed for a period of 38 months. There was no conflicting interest of any of the authors with respect to the authorship or publication of this article.
Applicability Implants restored according to platform switching concept is applicable to general dentist, restorative dentist, periodontist, oral surgeon and prosthodontist. The clinical evidence does not confirm the bone resorption-preventing effect of platform switching and thus treatment can be chosen according to the preferences of the clinician.
Specialty/Discipline (General Dentistry) (Oral Surgery) (Periodontics) (Prosthodontics) (Restorative Dentistry)
Keywords Bone level, bone loss, dental implants, implant design, platform switching.
ID# 2605
Date of submission: 01/11/2014spacer
E-mail rozee.rattani@ucdenver.edu
Author Rozee Rattani
Co-author(s) e-mail
Faculty mentor/Co-author Ronald N. Brown, DDS
Faculty mentor/Co-author e-mail Ronald.brown@ucdenver.edu
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
post a rationale
None available
Comments and Evidence-Based Updates on the CAT
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by Tyler Borg (San Antonio, TX) on 04/22/2014
Rozee, Thanks for the CAT! Recent meta-analyses and systematic reviews by both Atieh and Al-Nsour have shown that platform switching does in fact reduce marginal bone loss. The suggested horizontal abutment implant offset is 0.4 mm diameter. PMID: 20575657 PMID: 22299090.

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