Short-term bone level observations associated with platform switching in immediately placed and restored single maxillary implants: a preliminary report.
OBJECTIVE
The aim of this study was to evaluate the short-term bone level response around immediately placed and provisionally restored implants using a platform switching concept.


METHODS
Twenty-two implants with a platform diameter of 5.5 mm were immediately placed in healthy maxillary sites in 22 patients. Resultant circumimplant spaces were filled with a mixture of bovine bone matrix and collagen. The implants were randomly divided into two equal groups: 11 implants connected with 3.8-mm-diameter abutments (test group) and 11 with 5.5-mm-diameter ones (control). Provisional crowns were adapted and adjusted for nonfunctional immediate placement on each implant and the final crowns were constructed 2 months later. Posttreatment assessments were carried out by an independent trained observer at the time of implant placement (baseline), at definitive prosthesis insertion, and every 6 months thereafter. These assessments included periapical radiographs, pocket probing depths (PPD), bleeding on probing (BOP), and modified Plaque Index (mPII) on both implants and first proximal teeth. An image analysis software application was used to compare the bone crestal heights at the mesial and distal aspects of the implants.


RESULTS
The mean follow-up observation period was 25 months and all implants were judged to be successfully osseointegrated. In the test group, radiographic analysis showed an average bone reduction level of 0.30 mm (SD = 0.16 mm). This mean value was statistically significantly different (P < or = .005) from the average reduction in the control group (mean = 1.19 mm, SD = 0.35 mm). No differences between the two groups in PPD, BOP, or mPII were found.


CONCLUSIONS
This preliminary study suggests that immediate single implant restorations in specific maxillary sites with subsequent platform switching may provide peri-implant alveolar bone-level stability.
Canullo
Luigi
L
Department of Orthodontics, University of Bonn, Bonn, Germany. luigicanullo@yahoo.com
Goglia
Giuseppe
G
Iurlaro
Giorgia
G
Iannello
Giuliano
G
D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000145:classification; D000539:Alveolar Process / Q000473:pathology*; D001857:Bone Matrix / Q000637:transplantation; D018786:Bone Substitutes / Q000627:therapeutic use; D003094:Collagen / Q000627:therapeutic use; D003442:Crowns; D000044:Dental Abutments; D019250:Dental Implants, Single-Tooth; D003774:Dental Plaque Index; D003794:Dental Restoration, Temporary; D005260:Female; D005500:Follow-Up Studies; D005884:Gingival Hemorrhage / Q000145:classification; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008437:Maxilla / Q000473:pathology / Q000601:surgery*; D008875:Middle Aged; D008903:Minerals / Q000627:therapeutic use; D016348:Osseointegration / Q000502:physiology; D010514:Periodontal Pocket / Q000145:classification; D016300:Radiography, Bitewing; D016037:Single-Blind Method; D016896:Treatment Outcome
C077540:Bio-Oss; D018786:Bone Substitutes; D008903:Minerals; D003094:Collagen