Catharina Göthberg1,2, Ulrika André1, Kerstin Gröndahl3, Peter Thomsen2, Christer Slotte2,4. 1. Department of Prosthetic Dentistry, The Institute for Postgraduate Dental Education, Jönköping, Sweden. 2. Department of Biomaterials, VINN Excellence Center of Biomaterials and Cell Therapy, Institute for Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden. 3. Department of Oral and Maxillofacial Radiology, The Institute for Postgraduate Dental Education, Jönköping, Sweden. 4. Department of Periodontology, The Institute for Postgraduate Dental Education, Jönköping, Sweden.
Abstract
BACKGROUND: Diverging opinions exist regarding rough surface abutment usage, and abutment exclusion effects are unstudied. PURPOSE: The study aims to: (1) assess tissue response to oxidized or machined abutments or no abutment; and (2) evaluate immediate implant-loading effects. MATERIALS AND METHODS: In a 2005-2008 parallel-group randomized, clinical trial, 50 partially edentulous subjects received threeBrånemark TiUnite™ (Nobel Biocare®, Gothenburg, Sweden) implants. Superstructures were attached via abutments (one with a TiUnite surface - AOX, and one with a machine-milled surface - AM) or directly at implant level (IL). Implants were immediately loaded (test) or unloaded for 3 months (control). Postoperative examinations were done up to 3 years. RESULTS: Forty-seven subjects were reexamined after 3 years. Four and two implants were lost in test and control groups, respectively, during the first year. Thereafter, no implant loss occurred (95.7% survival). After 1 year, mean (SEM) peri-implant marginal bone loss (MBL) was 1.33 (0.08) mm (test) and 1.25 (0.08) mm (control). Between 1 and 3 years, a nonsignificant MBL occurred: 0.36 (0.08) mm (test) and 0.33 (0.06) mm (control). Similar MBL was found at IL (1.81 [0.93] mm) and AOX (1.77 [0.14] mm) after 3 years and was significantly lower at AM (1.42 [0.17] mm) than at IL (groups merged); 42% of the implants displayed mucosal bleeding at 3 years and probing pocket depths varied between 2.13 (0.12) mm and 3.62 (0.15) mm, significantly lower buccally. Bleeding on probing (BoP) in minute amounts was found in 30-45% of the sites and abundant BoP at about 20% of the sites. Soft tissue retracted mostly during year 1 and was more pronounced buccally. Regression analyses revealed significant effects from smoking, periodontal disease, abundant BoP, and a low initial implant stability quotient on MBL. CONCLUSIONS: No further significant MBL was found between 1 and 3 years, irrespective of loading protocol. Use of machined abutments may benefit marginal bone stability over time.
RCT Entities:
BACKGROUND: Diverging opinions exist regarding rough surface abutment usage, and abutment exclusion effects are unstudied. PURPOSE: The study aims to: (1) assess tissue response to oxidized or machined abutments or no abutment; and (2) evaluate immediate implant-loading effects. MATERIALS AND METHODS: In a 2005-2008 parallel-group randomized, clinical trial, 50 partially edentulous subjects received three Brånemark TiUnite™ (Nobel Biocare®, Gothenburg, Sweden) implants. Superstructures were attached via abutments (one with a TiUnite surface - AOX, and one with a machine-milled surface - AM) or directly at implant level (IL). Implants were immediately loaded (test) or unloaded for 3 months (control). Postoperative examinations were done up to 3 years. RESULTS: Forty-seven subjects were reexamined after 3 years. Four and two implants were lost in test and control groups, respectively, during the first year. Thereafter, no implant loss occurred (95.7% survival). After 1 year, mean (SEM) peri-implant marginal bone loss (MBL) was 1.33 (0.08) mm (test) and 1.25 (0.08) mm (control). Between 1 and 3 years, a nonsignificant MBL occurred: 0.36 (0.08) mm (test) and 0.33 (0.06) mm (control). Similar MBL was found at IL (1.81 [0.93] mm) and AOX (1.77 [0.14] mm) after 3 years and was significantly lower at AM (1.42 [0.17] mm) than at IL (groups merged); 42% of the implants displayed mucosal bleeding at 3 years and probing pocket depths varied between 2.13 (0.12) mm and 3.62 (0.15) mm, significantly lower buccally. Bleeding on probing (BoP) in minute amounts was found in 30-45% of the sites and abundant BoP at about 20% of the sites. Soft tissue retracted mostly during year 1 and was more pronounced buccally. Regression analyses revealed significant effects from smoking, periodontal disease, abundant BoP, and a low initial implant stability quotient on MBL. CONCLUSIONS: No further significant MBL was found between 1 and 3 years, irrespective of loading protocol. Use of machined abutments may benefit marginal bone stability over time.