Retrospective Cohort Study of 4,591 Straumann Implants Placed in 2,060 Patients in Private Practice with up to 10-Year Follow-up: The Relationship Between Crestal Bone Level and Soft Tissue Condition

Abstract

The purpose of this report is to describe the crestal bone level (CBL) around implants of various designs, describe the peri-implant soft tissue condition, and evaluate the relationship between the two over time. Materials and Methods: This retrospective cohort study reports on 2,060 patients with 4,591 implants evaluated after 3 months; 1, 3, 5, and 7 years; and up to 10 years. Periapical radiographs were used to evaluate changes in CBL. The peri-implant soft tissue was evaluated using a modified Bleeding Index termed the Implant Mucosal Index (IMI) where: 0 = no bleeding; 1 = minimal, single-point bleeding; 2 = moderate, multipoint bleeding; 3 = profuse, multipoint bleeding; and 4 = suppuration. Results: At 3 months, the mean CBL was 0.06 ± 0.22 mm; by 8 to 10 years, it had increased to 0.44 ± 0.81 mm. The median CBL remained stable throughout the study at < 0.1 mm. At 8 to 10 years, 15% of implants exhibited a CBL > 1.02 mm, and 5% exhibited a CBL > 2.28 mm. More than 50% of patients experienced some bleeding, as seen by an IMI ≥ 1 during follow-up. A positive correlation was found between IMI and CBL, as shown by a mean CBL after 4 years of 0.33 mm, 0.71 mm, and 1.52 mm for IMI = 2, 3, and 4, respectively. One exception was between IMI = 0 and IMI = 1, where no significant difference was found and bone loss was minimal. Conclusion: Bone loss, as measured by changes in CBL during the first 10 years of implant life spans, was minimal for most implants. Nevertheless, it is not unusual to observe implants with advanced bone loss. The soft tissue condition is a good indicator of bone loss. Time alone and minimal bleeding did not correlate with bone loss, but care should be taken for implants with profuse bleeding or suppuration. Int

Estimation of the diagnostic accuracy of clinical parameters for monitoring peri‐implantitis progression: An experimental canine study

“…Interestingly, implants placed in an incorrect bucco‐lingual position (thin buccal bone) were more prone to be associated with more overt clinical signs and hence to a more definitive disease diagnosis. Moreover, the present study tested two indexes proposed in the classic and recent literature for assessing marginal mucosal conditions . Both indexes demonstrated to be reliable for monitoring peri‐implant conditions, since both were strongly correlated to the progression of bone loss.…”

“…based the assessment of marginal mucosal condition on the presence and severity of edema, redness, glazing, ulceration, and bleeding with or without probing. More recently, French et al . modified the original scale described by Mombelli et al .…”

How do peri‐implant biologic parameters correspond with implant survival and peri‐implantitis? A critical review

“…It is therefore obvious that deeper pockets have a higher tendency to bleed. A recent large retrospective cohort study (French et al., 2016) of nearly 5,000 Straumann implants placed in 2,060 patients with up to 10‐year follow‐up concluded that time alone and minimal bleeding did not correlate with bone loss but that care should be taken for implants with profuse bleeding or suppuration. They found the highest mean bone loss around implants with suppuration and minor changes for implants with minimal to moderate or profuse bleeding.…”

“…This latter finding is in accordance with the results of the study of French et al. (2016). They specified that suppuration was detected in implants with the highest bone loss and suggested it could be useful for clinical diagnosis.…”

“…There was actually no difference in the proportion of implants with the absence or presence of bleeding/suppuration in relation to bone loss, bone gain, or bone stability (Roos‐Jansaker, Lindahl, Renvert & Renvert, 2006). Another large cohort study, including 4,591 implants from 2,060 subjects, indicated that minimal bleeding did not correlate with bone loss but multipoint bleeding, profuse bleeding, or suppuration did (French, Cochran & Ofec, 2016). The use of a dichotomous diagnostic criterion (bleeding yes or no) is probably the reason why often high figures of mucositis are reported.…”