Marginal Bone Maintenance and Different Prosthetic Emergence Angles: A 3-Year Retrospective Study

Abstract

The aim of the present retrospective study was to assess marginal bone changes around implants restored with different prosthetic emergence profile angles. Patients were treated with implants supporting fixed dentures and were followed for 3 years. Marginal bone levels (MBL) measured at the prosthesis installation (t0) and at the 3-year follow-up visit (t1) were considered. The MBL change from t0 to t1 was investigated. Two groups were considered: Group 1 for restorations with an angle between implant axis and prosthetic emergence profile >30°, and Group 2 for those with an angle ≤30°, respectively. Moreover, peri-implant soft tissue parameters, such as the modified bleeding index (MBI) and plaque index (PI) were assessed. Seventy-four patients were included in the analysis and a total of 312 implants were examined. The mean EA in groups 1 and 2 was 45 ± 4 and 22 ± 7 degrees, respectively. The mean marginal bone level change (MBL change) of 0.06 ± 0.09 mm and 0.06 ± 0.10 mm were, respectively, in groups 1 and 2. The difference in the MBL change between the two groups was not statistically significant (p = 0.969). The MBL change does not seem to be influenced by the emergence angle for implants with a stable internal conical connection and platform-switching of the abutment diameter.

Association between Peri-Implant Soft Tissue Health and Different Prosthetic Emergence Angles in Esthetic Areas: Digital Evaluation after 3 Years’ Function

“…All implants were restored by means of a 5° internal conical connection and a platform shifting of the prosthetic abutments from the fixture diameter. Such feature, related to the implant-to-abutment connection, seems to be effective in the maintenance of peri-implant bone stability in the mid-to-long term [ 10 ]. After 3 years of follow-up, EA digitally measured on the buccal side was correlated to peri-implant soft tissue parameters as PPD, PI and GI indexes, respectively.…”

“…As previously described by Lops et al [ 10 ] a submerged healing technique was chosen for the implants that were placed (Anyridge, Megagen Implants, Seoul, Korea) 1 to 2 mm below the crestal level [ 15 ], as recommended by the manufacturer.…”

“…On the other hand, in a 3-year follow-up report, no direct correlation between MBL (marginal bone level) change and emergence angles was found by Lops et al [ 10 ]. Moreover, limited evidence about this correlation was highlighted by Mattheos et al [ 13 ] in a critical review.…”

“…Additionally, emergence profile zones were classified [ 9 ] in order to describe their importance in peri-implant tissue shaping and fulfilling aesthetic outcomes. Among such aesthetic criteria, interproximal papilla contour, gingival margin scalloping and buccal soft tissue thickness should be considered [ 10 ]. In addition, soft tissue architecture may contribute to preventing peri-implant soft tissue inflammation, giving patients real chances to follow proper oral hygiene indications [ 11 ].…”

Correlation between accuracy in computer guided implantology and peri-implant tissue stability: a prospective clinical and radiological pilot study

“…To solve the problem of distortion, the measurements were calibrated on the basis of a known landmark, in this case the known length of the implant itself. In cases where the peri-implant marginal bone level was more coronal than the implant shoulder as a result of apico-coronal placement of the implant deeper than the bone crest, the value "0" was reported, regardless of the actual distance between the two references [10].…”