A Systematic Review of Survival Rates of Osseointegrated Implants in Fully and Partially Edentulous Patients Following Immediate Loading

Background: The aim of this systematic review was to evaluate the survival rates of immediately loaded implants after at least five years. Besides implant failure, the amount of marginal bone loss around implants and the complication type were assessed. Methods: The electronic search was undertaken on Medline, Scopus, and Cochrane Central Register of Controlled Trials using key terms such as: “immediate loading”, “immediate function”, “immediate restoration”, “immediate temporization”, “dental implants”, “fully edentulous patients”, “partially edentulous patients”. The search terms were combined using the Boolean operators AND, OR. The last electronic search was performed on 15 February 2018. Two authors independently screened the studies, extracted the data, and assessed the risk-of bias. The main outcomes recorded for each study were: implant and prosthesis success and survival, marginal bone level change, incidence and type of complications. Kaplan–Meier analysis was used to estimate cumulative survival rates. Results: Thirty-four prospective studies with at least five-year follow-up, published between 2007 and 2017 were included. A total of 5349 immediately loaded implants in 1738 patients were analyzed. The mean follow-up was 72.4 months (median 60 months, 95% confidence intervals (CI): 64.53, 80.25 months, range 60 to 147 months). The mean weighted implant survival was 97.4% (median 98.15%, 95% CI: 96.29%, 98.54%, range 83.80% to 100%). Cumulative survival rate of implants placed in the mandible was significantly higher than for the maxilla (p < 0.01). No significant difference in failure rate was found among the types of prosthesis employed (p = 0.27). The mean peri-implant bone level change at the end of the follow-up in each study ranged from 0.3 to 1.7 mm. Conclusion: Immediate loading of implants appears to have long-term predictability and success rate under well-defined circumstances.

Novel Use of Silicone Sheets for Immediate Implant Placement in Fresh Molar Extraction Sockets

In the recent years, the immediate placement of dental implants into fresh extraction sites has become an acceptable treatment approach. However, immediate molar implant placement presents specific challenges because of the anatomical and physiologic limitations. Such implant surgeries commonly require procedures that use a barrier membrane to generate bone and soft tissue or one that seals the molar extraction socket through a coronally advanced flap. Here, as an alternative, we report a method for treating molar extraction socket wounds in the hard and soft tissues after immediate placement of an implant using a silicone sheet.

Immediate loading vs. early/conventional loading of immediately placed implants in partially edentulous patients from the patients' perspective: A systematic review

OBJECTIVES

This systematic review aimed at answering the following PICO question: In patients receiving immediate (Type 1) implant placement, how does immediate compare to early or conventional loading in terms of Patient-Reported Outcome Measures (PROMs)?

MATERIAL AND METHODS

Following search strategy development, the OVID, PubMed, EMBASE, and Cochrane Database of Systematic Reviews databases were search for the relevant literature. All levels of evidence including randomized controlled trials, prospective and retrospective cohort studies, and case series of at least five patients were considered for possible inclusion. An additional manual search was performed by screening the reference lists of relevant studies and systematic reviews published up to May 2017. The intervention considered was the placement of immediate implant. Study selection and data extraction were performed independently by two reviewers.

RESULTS

The search yielded a list of 1,102 references, of which nine were included in this systematic review. The limited number of studies included and the heterogeneity of the data identified prevented the performance of a meta-analysis. Three studies, one of which was a randomized controlled trial, allowed the extraction of comparative data specific to the aim of the present systematic review. The remaining studies allowed only data extraction for one single treatment modality and were viewed as single cohort studies. Overall, irrespective of the PROMs chosen, patients' satisfaction was overall high with little difference between the two loading protocols. Moreover, studies indicated a positive impact on oral health-related quality of life following immediate implant placement and loading.

CONCLUSIONS

Within the limitations of the present systematic review, immediate implant placement and loading in single tooth edentulous space seems to be a well-accepted treatment modality from the patients' perspective and is worthy of consideration in clinical practice. However, the paucity of comparative data limits any definitive conclusions as to which loading protocol; immediate or early/conventional, should be given preference based on PROMs.

Implant placement and loading protocols in partially edentulous patients: A systematic review

OBJECTIVES

To systematically review the evidence for the clinical outcome of fixed implant prostheses treated with different combinations of implant placement and loading protocols in partially edentulous patients.

MATERIALS AND METHODS

An electronic search was performed in Medline, Embase, and Central to identify studies investigating the outcome of implants subjected to immediate placement + immediate restoration/loading (Type 1A), immediate placement + early loading (Type 1B), immediate placement + conventional loading (Type 1C), early placement + immediate restoration/loading (Type 2-3A), early placement + early loading (Type 2-3B), early placement + conventional loading (Type 2-3C), late placement + immediate restoration/loading (Type 4A), late placement + early loading (Type 4B), late placement + conventional loading (Type 4C) with implant-supported fixed dental prostheses (IFDPs) in partially edentulous patients. Only human studies with at least 10 cases and a minimum follow-up time of 12 months, reporting on solid-screw-type implants with rough surfaces and an intra-osseous diameter between 3 and 6 mm, were included. A cumulative survival rate for each type of the implant placement and loading protocols was weighted by the duration of follow-up and number of implants.

RESULTS

The search provided 5,248 titles from which 2,362 abstracts and 449 full-text articles were screened. A total of 69 publications that comprised 23 comparative studies (15 randomized controlled trials, 7 controlled clinical trials) and 47 noncomparative studies (34 prospective cohort studies, 13 retrospective cohort studies) were included for analysis. Considerable heterogeneity in study design was found, and therefore, a meta-analysis of controlled studies was not possible. The weighted cumulative survival rate of each type of placement and loading protocol was 98.4% (Type 1A), 98.2% (Type 1B), 96.0% (Type 1C), 100% (Type 2-3B), 96.3% (Type 2-3C), 97.9% (Type 4A), 98.3% (Type 4B), and 97.7% (Type 4C). Type 1C, Type 2-3C, Type 4B, and Type 4C were scientifically and clinically validated (SCV). Type 1A, Type 1B, and Type 4A were clinically documented (CD), and Type 2-3A and Type 2-3B were clinically insufficiently documented (CID).

CONCLUSIONS

Evaluating outcomes in oral implantology by combining the placement and loading protocols are paramount. The selected loading protocol appears to influence the outcome of immediate implant placement.

Implant rehabilitation of the edentulous jaws: Does tilting of posterior implants at an angle greater than 45° affect bone resorption and implant success?: A retrospective study

PURPOSE

This study aimed to (1) investigate the success of posterior implants tilted >45° when 4 immediately loaded implants were used to support full-arch prostheses, eliminating any distal cantilever and (2) examine the effect on marginal bone loss (MBL) of different combinations of anterior multi-unit abutment (MUA) angles and posterior implant tilting angles.

MATERIALS AND METHODS

Records of patients rehabilitated according to the Columbus Bridge Protocol were analyzed. Peri-implant bone levels (PBLs) and MBL were measured for each implant. The influence of posterior implant tilting angle on PBL, MBL, and implant and prosthetic success rate was investigated. The impact on the same endpoints of different anterior MUA angles, and different combinations of anterior MUA and tilted posterior implant angles was also examined.

RESULTS

Records of 41 patients were analyzed, for a total of 46 complete rehabilitations, and 142 implants (52 anterior, 63 posterior tilted ≤45° [group 1], and 27 posterior tilted >45° [group 2]). No implants were lost during the follow-up (25.9 months), and no prosthetic complications were reported. Success rate for posterior implants was 100% in group 1 and 96.3% in group 2. Mean MBL differed significantly between the 2 groups (0.45 mm in group 1, 0.66 in group 2 [P = .04]), but not when the analysis was limited to implants in the same jaw. Implant tilting angle did not correlate with MBL and the MUA angle had no effect on bone resorption around posterior implants, neither in the sample as a whole nor in individual patients.

CONCLUSIONS

Posterior implants tilted >45° to eliminate distal cantilever may be as safe as those tilted less in severely atrophic jaws rehabilitated with immediately loaded, full-arch prostheses supported on 4 implants. Further prospective studies on larger samples of patients and implants and with longer follow-up are needed to confirm these findings.

Complications, risk factors, and failures of immediate functional loading of implants placed in the completely edentulous maxillae: a report of 3 consecutive cases

PURPOSE

The aim of this article was to document the failure of immediate functional loading of implants placed in 3 consecutive completely edentulous maxillae to analyze the possible causes, risk factors, and how to avoid the complications that occur due to this procedure.

MATERIALS AND METHODS

Six implants with standardized length and diameter were placed in 3 consecutive patients with completely edentulous maxillae in the canine, premolar, and molar region bilaterally and flaplessly using computer-guided surgical guides. Screw-retained conversion maxillary prostheses were delivered immediately after the surgery.

RESULTS

Patients complained from severe to moderate pain. For the first and second patients (P1 and P2), 4 implants per patient were lost during the second week after implant surgery, whereas 5 implants were lost during the third week after implant surgery for the third patient (P3).

CONCLUSION

This high failure rate presented in this report may be explained by 1 or more of the following reasons: poor maxillary bone quality, nonaxial loading of the implants, nonrigid splinting material, high forces delivered from the opposing dentition, and/or patients with para-functional habits.

Clinical evaluation of short and wide-diameter implants immediately placed into extraction sockets of posterior areas: a 2-year retrospective study

The objective of the study was to determine the short-term success rate of short and wide single-tooth implants, immediately placed into extraction sockets of the posterior area. A retrospective cohort study design was used. A total of 145 subjects received 162 short and wide-diameter single-tooth implants between 2006 and 2009. A minimal 7-mm residual height and 9-mm ridge width was available in all the implant sites, and the attached gingivae were at least 2 mm wide. All implants were placed and restored with the single crown by one experienced operator. The data were analyzed with descriptive statistics. All implants were placed in molar areas. There were 20 Ankylos implants with a diameter 5.5 or 7 mm and a length of 8 mm and 142 hydroxyapatite-coated implants with a diameter 5 or 6 mm and a length of 5.7 to 8 mm. One of the 162 implants failed before prosthetic restoration, resulting in a survival rate of 99.4% after loading. Patients were followed for up to 56 months (mean = 24 months) after loading of implants. The radiographic and clinical data revealed well-maintained hard and soft tissues with acceptable short-term results. For residual ridges with minimal height but adequate width, the immediate placement of short and wide-diameter implants in fresh extraction sockets may offer a simple and predictable treatment alternative if implants are positioned appropriately after a thorough preoperative analysis.

In vivo monitoring of the bone healing process around different titanium alloy implant surfaces placed into fresh extraction sockets

OBJECTIVES

Increasing surface roughness and coating with tricalcium phosphate of titanium and titanium alloy implants has been proposed to provide better rates of osseointegration. However, how these changes in surface topography and chemistry influence the osseointegration process of immediate implants placed in fresh extraction sockets is unclear. This study investigated the influence of three clinically employed implant surfaces on the early bone healing events in vivo.

METHODS

Machined smooth implants were milled from grade 5 Ti6Al4V titanium. Surfaces were moderately roughened by grit blasting, which were then coated with tricalcium phosphate. Implants were placed into freshly extracted incisor sockets of mandibles of normal Wistar rats and left for 1, 3 and 9 weeks. Healing bone tissue around the implants was examined by histochemistry and immunocytochemistry to localise PCNA proliferative cells, and osteoblast differentiation markers osteopontin and osteocalcin. Positive synthesising cells were counted using image analysis.

RESULTS

Histology indicated no differences in the amount or pattern of bone formation within the healing tissue surrounding the different implant surfaces. Bone healing occurred predominantly on exposed bone surfaces (distance osteogenesis) and not on the implant surface (contact osteogenesis). No differences were observed in the number or timing of PCNA, osteopontin and osteocalcin positive cells within the bone healing tissue around each of the implant analysed.

CONCLUSION

For immediately placed implants, the surface modifications investigated appeared to have little influence on the activity of bone forming cells surrounding the implant, probably due to the high level of distance osteogenesis seen within this scenario.

CLINICAL SIGNIFICANCE

For immediate placement of implants into fresh extraction sockets, titanium implants with roughened surfaces and coating with tricalcium phosphate have negligible influence in accelerating the early bone healing events of osseointegration.

Fractal Patterns Applied to Implant Surface: Definitions and Perspectives

Fractal patterns are frequently found in nature, but they are difficult to reproduce in artificial objects such as implantable materials. In this article, a definition of the concept of fractals for osseointegrated surfaces is suggested, based on the search for quasi-self-similarity on at least 3 scales of investigation: microscale, nanoscale, and atomic/crystal scale. Following this definition, the fractal dimension of some surfaces may be defined (illustrated here with the Intra-Lock Ossean surface). However the biological effects of this architecture are still unknown and should be examined carefully in the future.

Identification card and codification of the chemical and morphological characteristics of 14 dental implant surfaces

Dental implants are commonly used in daily practice; however, most surgeons do not really know the characteristics of these biomedical devices they are placing in their patients. The objective of this work is to describe the chemical and morphological characteristics of 14 implant surfaces available on the market and to establish a simple and clear identification (ID) card for all of them, following the classification procedure developed in the Dohan Ehrenfest et al (2010) Codification (DEC) system. Fourteen implant surfaces were characterized: TiUnite (Nobel Biocare), Ospol (Ospol), Kohno HRPS (Sweden & Martina), Osseospeed (AstraTech), Ankylos (Dentsply Friadent), MTX (Zimmer), Promote (Camlog), BTI Interna (Biotechnology Institute), EVL Plus (SERF), Twinkon Ref (Tekka), Ossean (Intra-Lock), NanoTite (Biomet 3I), SLActive (ITI Straumann), Integra-CP/NanoTite (Bicon). Three samples of each implant were analyzed. Superficial chemical composition was analyzed using X-ray photoelectron spectroscopy/electron spectroscopy for chemical analysis, and the 100 nm in-depth profile was established using Auger electron spectroscopy. The microtopography was quantified using light interferometry. The general morphology and nanotopography were evaluated using a field emission-scanning electron microscope. Finally, the characterization code of each surface was established using the DEC system, and the main characteristics of each surface were summarized in a reader-friendly ID card. From a chemical standpoint, of the 14 different surfaces, 10 were based on a commercially pure titanium (grade 2 or 4), 3 on a titanium-aluminum alloy (grade 5 titanium), and one on a calcium phosphate core. Nine surfaces presented different forms of chemical impregnation or discontinuous coating of the titanium core, and 3 surfaces were covered with residual aluminablasting particles. Twelve surfaces presented different degrees of inorganic pollutions, and 2 presented a severe organic pollution overcoat. Only 2 surfaces presented no pollution (Osseospeed and Ossean). From a morphological standpoint, 2 surfaces were microporous (anodization) and 12 were microrough, with different microtopographical aspects and values. Ten surfaces were smooth on the nanoscale, and therefore presented no significant and repetitive nanostructures. Four implants were nanomodified: 2 implants were nanorough (Osseospeed and Ossean), and 2 were covered with nanoparticles (NanoTite and SLActive). TiUnite and Kohno HRPS were covered with extended cracks all over the surface. Only 8 surfaces could be considered homogeneous. This systematic approach allowed the main characteristics of these commercially available products to be gathered in a single ID card. It can be used as an experimental tool or a method for controlling industrial implant productions. The DEC system could be an interesting basis for the development of a clear and simple ISO standard for dental implant surfaces and other implantable devices.