Single immediate implants showed high implant survival and limited marginal bone loss in the long term. However, mid-facial recession, mid-facial contour and alveolar process deficiency deteriorated after 1 year. With an aesthetic complication rate of 8/17 in well-selected patients who had been treated by experienced clinicians, type I placement may not be recommended for daily practice.

The present study suggests that implants with lower abutments, reflecting the initial gingival thickness, lose more peri-implant bone, possibly by a re-establishment of the biological width.

Aim To compare immediate implant placement (IIP) to delayed single implant placement (DIP, ≥3 months post‐extraction) in terms of implant survival (primary outcome), surgical, clinical, aesthetic, radiographic and patient‐reported outcomes (secondary outcomes). Materials and Methods Two reviewers independently performed an electronic search in PubMed, Web of Science, EMBASE and Cochrane and a hand search to identify eligible studies up to May 2018. Only randomized controlled trials (RCTs) and non‐randomized controlled studies (NRSs) comparing IIP to DIP with at least 1 year of follow‐up were selected for a qualitative analysis and meta‐analysis. Results The search identified 3 RCTs and 5 NRSs out of 2,589 titles providing data on 473 single implants (IIP: 233, DIP: 240) that had been in function between 12 and 96 months. One RCT showed unclear risk of bias, whereas all other studies demonstrated high risk. Meta‐analysis showed significantly lower implant survival for IIP (94.9%) as compared to DIP (98.9%) (RR 0.96, 95% CI [0.93; 0.99], p = 0.02). All were early implant failures. A subgroup meta‐analysis demonstrated a trend towards lower implant survival for IIP when postoperative antibiotics had not been administered (RR: 0.93, 95% CI [0.86; 1.00], p = 0.07). This was not observed among studies including the administration of postoperative antibiotics (RR: 0.98, 95% CI [0.94; 1.02], p = 0.35). Meta‐analyses showed similar probing depth (WMD 0.43 mm, 95% CI [−0.47; 1.33], p = 0.35) and aesthetic outcomes as assessed by the pink aesthetic score (standardized WMD −0.03, 95% CI [−0.46; 0.39], p = 0.88) for IIP and DIP. Data on marginal bone loss were conflicting and highly biased. Soft tissue recession was underreported and available data were highly biased. Patient‐reported outcomes were underreported, yet both IIP and DIP seemed well tolerated. Conclusion Immediate implant placement demonstrated higher risk for early implant loss than DIP. There is a need for RCTs comparing IIP to DIP with CBCT analyses at different time points and data on midfacial recession with the preoperative status as baseline. In these studies, the need for hard and soft tissue grafting should also be evaluated.

Publications from 2011 to 2015 were selected to evaluate effect of implant surface roughness on long-term bone loss as surrogate for peri-implantitis risk. 87 out of 2,566 papers reported the mean bone loss after at least 5 years of function. Estimation of the proportion of implants with bone loss above 1, 2, and 3 mm as well as analysis the effect of implant surface roughness, smoking, and history of periodontitis was performed. By means of the provided statistical information of bone loss (mean and standard deviation) the prevalence of implants with bone loss ranging from 1 to 3 mm was estimated. The bone loss was used as a surrogate parameter for "peri-implantitis" given the fact that "peri-implantitis" prevalence was not reported in most studies or when reported, the diagnostic criteria were unclear or of dubious quality. The outcome of this review suggests that peri-implant bone loss around minimally rough implant systems was statistically significant less in comparison to the moderately rough and rough implant systems. No statistically significant difference was observed between moderately rough and rough implant systems. The studies that compared implants with comparable design and different surface roughness, showed less average peri-implant bone loss around the less rough surfaces in the meta-analysis. However, due to the heterogeneity of the papers and the multifactorial cause for bone loss, the impact of surface roughness alone seems rather limited and of minimal clinical importance. Irrespective of surface topography or implant brand, the average weighted implant survival rate was 97.3% after 5 years or more of loading. If considering 3 mm bone loss after at least 5 years to represent the presence of "peri-implantitis," less than 5% of the implants were affected. The meta-analysis indicated that periodontal history and smoking habits yielded more bone loss.

Dental implant placement is a common treatment procedure in current dental practice. High implant survival rates as well as limited peri-implant bone loss has been achieved over the past decades due to continuous modifications of implant design and surface topography. Since the turn of the millennium, implant surface modifications have focused on stronger and faster bone healing. This has not only yielded higher implant survival rates but also allowed modifications in surgical as well as prosthetic treatment protocols such as immediate implant placement and immediate loading. Stable crestal bone levels have been considered a key factor in implant success because it is paramount for long-term survival, aesthetics as well as peri-implant health. Especially during the past decade, clinicians and researchers have paid much attention to peri-implant health and more specifically to the incidence of bone loss. This could furthermore increase the risk for peri-implantitis, the latter often diagnosed as ongoing bone loss and pocket formation beyond the normal biological range in the presence of purulence or bleeding on probing. Information on the effect of surface topography on bone loss or peri-implantitis, a disease process that is to be evaluated in the long-term, is also scarce. Therefore, the current narrative review discusses whether long-term peri-implant bone loss beyond physiological bone adaptation is affected by the surface roughness of dental implants. Based on comparative studies, evaluating implants with comparable design but different surface roughness, it can be concluded that average peri-implant bone loss around the moderately rough and minimally rough surfaces is less than around rough surfaces. However, due to the multifactorial cause for bone loss the clinical impact of surface roughness alone on bone loss and peri-implantitis risk seems rather limited and of minimal clinical importance. Furthermore, there is growing evidence that certain patient factors, such as a history of periodontal disease and smoking, lead to more peri-implant bone loss.