Dental Implants with Internal versus External Connections: 10-year Post-Loading Results of a Pragmatic Multicentre Randomised Controlled Trial

PURPOSE. To compare the effectiveness of identical implants with internal or external connections. MATERIALS AND METHODS. One hundred and twenty patients with any type of edentulism (single tooth, partial or total edentulism) requiring one implant-supported prosthesis were randomly allocated at four centres to two equal groups to receive either implants with external connection (EC) or implants of the same type but with internal connection (IC) (EZ Plus, MegaGen Implant, Gyeongbuk, South Korea). Due to slight differences in implant design/components, IC implants were platform-switched while ECs were not. Patients were followed up for 10 years after initial loading. Outcome measures were: Any prosthesis/implant failures, complications, and marginal bone level changes, as assessed by blinded outcome assessors whenever possible. RESULTS. Sixty patients received 96 EC implants and 60 patients 107 IC implants. Eight patients from the EC group and nine from the IC group dropped out, but all remaining patients were followed up to 10 years post-loading. Two EC patients experienced implant and prosthesis failures versus three IC patients (P = 0.631, diff = 0.02, 95% CI: -0.07 to 0.11). Fifteen complications occurred in 13 EC patients versus 13 complications in 11 IC patients (P = 0.720, diff. = -0.03, 95%o CI: -0.19 to 0.13). There were no statistically significant differences for prosthesis and implant failures and complications between the different con-nection types. Ten years after loading, both groups had lost a significant amount of bone (1.01 mm at EC implants and 1.27 mm at IC implants), but there was no statistically signi-ficant difference in estimated marginal bone levels between the two groups (diff. = 0.07 mm, 95% CI: -0.41 to 0.54 mm, P (ANCOVA) = 0.782). CONCLUSIONS. Acknowledging the difference between EC and IC implants in terms of neck design and platform-switching, 10-year post-loading data revealed no statistically significant differences between the two connection types, and clinicians can therefore choose which they prefer. CONFLICT OF INTEREST STATEMENT. This trial was partially funded by MegaGen Implant, Gyeongbuk, South Korea, the manufacturer of the implants evaluated in this investigation. However, the resulting data belonged to the authors and by no means did the manufacturer interfere with the conduct of the trial or the publication of the results

The Impact of Repeated Abutment Changes on Peri-implant Tissue Stability: Five-year Post-loading Results From a Multicentre Randomised Controlled Trial

PURPOSE. To evaluate the impact of at least three abutment disconnections on hard and soft tissues around conventionally loaded implants versus definitive immediately non-oc-clusally loaded abutments in implants. A secondary aim was to evaluate whether the presence of less than 2 mm of keratinised mucosa is associated with increased soft tissue recession and/or peri-implant marginal bone loss. MATERIALS AND METHODS. Eighty patients requiring one single crown or one fixed partial prosthesis supported by a maximum of three implants were randomised, after implant placement at greater than 35 Ncm, according to a parallel-group design to receive either definitive immediately loaded abutments (definitive abutment or immediate loading group) or transmucosal abutments which were loaded after a delay of 3 months and removed at least three times. Patients were treated in four centres, and each patient contributed to the study with only one prosthesis, which was followed up for 5 years after initial loading. Outcome measures were: prosthesis failures, implant failures, complica-tions, pink aesthetic score (PES), buccal recessions, patient satisfaction, peri-implant marginal bone-level changes and height of the keratinised mucosa. RESULTS. Forty patients were randomly allocated to each group according to a paral-lel-group design. Seven patients from the definitive abutment group versus six from the repeated disconnection group dropped out or died. No patient from the definitive group had implant failures versus three patients who lost five implants in the repeated disconnection group (difference = 9.1%; CI95%:-0.7% to 18.9% to; P = 0.227). Nine patients from the repeated disconnection group lost or had to have their prosthesis remade (four provisional and five definitive prostheses) versus one provisional prosthesis failure in the definitive abutment group; this difference was statistically significant (difference = 23.5%; CI95%: 7.6% to 39.4%; P = 0.017), but was due to the erroneous use of non-indexed abutments in indexed implants in patients from the repeated disconnection group alone. Seven patients from the definitive abutment group versus nine patients from the repeated disconnection group were affected by complications (difference =-5.9%; CI95%:-26.0% to 14.2%; P = 0.775), the difference being not statistically significant. PES scores assessed at 5 years post-loading were 12.1±1.8 for the definitive abutment group and 11.9±1.7 for the repeated abutment changes group (difference = 0.2; CI95%:-0.7 to 1.1; P = 0.615); however, there was a statistically significant difference of 0.20 out of a maximum score of 2 in favour of the definitive abutment group for soft tissue contour alone (P = 0.045). Buccal recessions at 5 years post-loading amounted to-0.19±0.77 mm for the definitive abutment group and-0.07±1.24 mm for the repeated abutment changes group (difference = 0.12 mm CI95%:-0.42 to 0.66; P = 0.662). All patients declared being very satisfied or sati-sfied with the function and aesthetics of their prosthesis and would undergo the same procedure again. Mean peri-implant marginal bone loss 5 years after loading was 0.11±0.30 mm for the definitive abutment group and 0.48±0.73 mm for the repeated abutment change group (difference =-0.37 [SE=0.14] mm; CI95%:-0.66 to-0.09; P = 0.012), the difference being statistically significant. The height of keratinised mucosa at 5 years post-loading was 2.81±1.46 mm in the definitive abutment group and 2.83±1.84 mm in the repeated abutment change group (difference =-0.02 mm; CI95%:-0.85 to 0.80; P = 0.956), and there were no significant differences in marginal bone loss (difference = 0.00 mm; CI95%:-0.32 to 0.32, P = 0.990) or buccal recession (difference = 0.05 mm, CI95%:-0.43 to 0.54, P = 0.826) at implants having less than 2 mm of keratinised mucosa at loading compared to those having more than 2 mm of keratinised mucosa. CONCLUSIONS. Five-year post-loading data show that at least three repeated abutment disconnections significantly increased bone loss by 0.37 mm when compared to no di-sconnection, but this difference may not be clinically significant. While it might be advi-sable to avoid unnecessary abutment disconnection whenever possible, if disconnections are required, no clinically significant side effects may be expected. Immediately non-oc-clusally loaded dental implants are a viable alternative to conventional loading, and no increased bone loss or buccal recessions were noted even at implants with less than 2 mm of keratinised mucosa

Biologic Agents to Promote Periodontal Regeneration and Bone Augmentation

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142088/1/cap0080.pd