RCT comparing minimally with moderately rough implants. Part 1: clinical observations

Impact of surface characteristics on the peri-implant microbiome in health and disease

BACKGROUND

Because little is known about the impact of implant surface modifications on the peri-implant microbiome, we aimed to examine peri-implant communities in various surface types in order to better understand the impact of these surfaces on the development of peri-implantitis (PI).

METHODS

One hundred and six systemically healthy individuals with anodized (AN), hydroxyapatite-coated (HA), or sandblasted acid-etched (SLA) implants that were >6 months in function were recruited and categorized into health (H) or PI. Peri-implant biofilm was analyzed using 16S rRNA gene sequencing and compared between health/disease and HA/SLA/AN using community-level and taxa-level metrics.

RESULTS

Healthy implants did not demonstrate significant differences in clustering, alpha- or beta-diversity based on surface modification. AN and HA surfaces displayed significant differences between health and PI (p < 0.05); however, such a clustering was not evident with SLA (p > 0.05). AN and HA surfaces also differed in the magnitude and diversity of differences between health and PI. Six species belonging to the genera Shuttleworthia, Scardovia, and Prevotella demonstrated lower abundances in AN implants with PI, and 18 species belonging to the genera Fretibacterium, Tannerella, Treponema, and Fusobacterium were elevated, while in HA implants with PI, 20 species belonging to the genera Streptococcus, Lactobacillus, Veillonella, Rothia, and family Ruminococcaceae were depleted and Peptostreptococcaceae, Atopobiaceae, Veillonellaceae, Porphyromonadaceae, Desulfobulbaceae, and order Synergistales were enriched.

CONCLUSIONS

Within the limitations of this study, we demonstrate that implant surface can differentially modify the disease-associated microbiome, suggesting that surface topography must be considered in the multi-factorial etiology of peri-implant diseases.

Surface Modifications of Commercial Dental Implant Systems: An Overview

The aim of this review was to perform a comprehensive overview of evidence pertaining to the influence of various surface modifications on the surface roughness, bone implant contact, and the success and complication rates of the implants. Modified sandblasted, large-grit, acid-etched (SLA) implants (SLActive implants) have a higher implant stability quotient compared with conventional SLA implants. Also, when compared between the implant surfaces from various manufacturers, Biomet 3i Nanotite implants were shown to have a relatively higher implant stability quotient compared to Straumann implants as well as the Biomet Osseotite implants. Only one study reports the insertion torque values as obtained by the various implant surfaces, with the findings being statistically similar for all the types, and a higher mean value for Biomet 3i Nanotite implants. Among SLA and SLActive surfaces, the latter was found to have a lower marginal bone loss, and among Astratech implants, the marginal bone loss levels were similar for Osseospeed and Tioblast surfaces. When Osseospeed, TiUnite and SLActive surfaces were compared, Osseospeed was found to have the minimum bone loss while TiUnite was found to have the highest. The bone implant contact percentages are similar and satisfactory for most of the implant surface modifications that are available currently. Upon assessing the recent literature on the survival rates for implants with various surface modifications, it was found that among Nobel Biocare implants, the survival rate was higher for TiUnite implants, compared with the turned surfaces. Surprisingly, among the Straumann implant surfaces, the survival rates were found to be higher for the SLA implants when compared to the modified SLA implants. Only one of the included studies evaluated the survival rate for Astratech implant surfaces and found a 100% survival rate for both the Osseospeed and Tioblast surface implants. Therefore, major advancements have been made in developing novel surfaces of dental implants. The numerous innovations set the stage for rehabilitating patients with high success and predictable survival rates even in challenging conditions.

WITHDRAWN: Interventions for replacing missing teeth: different types of dental implants

BACKGROUND

Dental implants are available in different materials, shapes and with different surface characteristics. In particular, numerous implant designs and surface modifications have been developed for improving clinical outcome. This is an update of a Cochrane review first published in 2002, and previously updated in 2003, 2005 and 2007.

OBJECTIVES

Primary: to compare the clinical effects of different root-formed osseointegrated dental implant types for replacing missing teeth for the following specific comparisons: implants with different surface preparations, but having similar shape and material; implants with different shapes, but having similar surface preparation and material; implants made of different materials, but having similar surface preparation and shape; different implant types differing in surface preparation, shape, material or a combination of these.Secondary: to compare turned and roughened dental implants for occurrence of early implant failure (before prosthetic loading) and occurrence of peri-implantitis.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Oral Health Group's Trials Register (to 17 January 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 12), MEDLINE via OVID (1946 to 17 January 2014) and EMBASE via OVID (1980 to 17 January 2014). We placed no restrictions on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included any randomised controlled trial (RCT) comparing osseointegrated dental implants of different materials, shapes and surface properties having a follow-up in function of at least one year. Outcome measures were success of the implants, radiographic peri-implant marginal bone levels changes and incidence of peri-implantitis.

DATA COLLECTION AND ANALYSIS

At least two review authors independently conducted screening, risk of bias assessment and data extraction of eligible trials in duplicate. We expressed results using fixed-effect models (if up to three studies were present in a meta-analysis) or random-effects models (when there were more than three studies) using mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI). We reported the following endpoints: one, three, five and 10 years after functional loading.

MAIN RESULTS

We identified 81 different RCTs. We included 27 of these RCTs, reporting results from 1512 participants and 3230 implants in the review. We compared 38 different implant types with a follow-up ranging from one to 10 years. All implants were made of commercially pure titanium or its alloys, and had different shapes and surface preparations. We judged two trials to be at low risk of bias, 10 to be at unclear risk of bias and 15 to be at high risk of bias. On a 'per participant' rather than 'per implant' basis, we found no significant differences between various implant types for implant failures. The only observed statistically significant difference for the primary objective regarded more peri-implant bone loss at Nobel Speedy Groovy implants when compared with NobelActive implants (MD -0.59 mm; 95% CI -0.74 to -0.44, different implant shapes). The only observed statistically significant difference for the secondary objective was that implants with turned (smoother) surfaces had a 20% reduction in risk to be affected by peri-implantitis than implants with rough surfaces three years after loading (RR 0.80; 95% CI 0.67 to 0.96). There was a tendency for implants with turned surfaces to fail early more often than implants with roughened surfaces.

AUTHORS' CONCLUSIONS

Based on the results of the included RCTs, we found no evidence showing that any particular type of dental implant had superior long-term success. There was limited evidence showing that implants with relatively smooth (turned) surfaces were less prone to lose bone due to chronic infection (peri-implantitis) than implants with much rougher surfaces (titanium-plasma-sprayed). These findings were based on several RCTs, often at high risk of bias, with few participants and relatively short follow-up periods.

Prevalence of Peri-Implantitis in Implants with Turned and Rough Surfaces: a Systematic Review

Objectives

Moderately-rough implant surface may improve implant therapy in terms of bone integration, but the increased surface roughness might affect the initiation and development of peri-implantitis. The aim of the present review was to compare the prevalence of peri-implantitis in implants with rough and turned (machined) implant surfaces.

Material and Methods

An electronic literature search was conducted of the MEDLINE and EMBASE databases for articles published between 1 January 1990 and 1 March 2018. Clinical human studies in the English language that had reported on prevalence of peri-implantitis in tuned and rough surface implants were searched. The initial search resulted in 690 articles.

Results

Eight articles with 2992 implants were included in the systematic review. The incidence of peri-implantitis for two implant surfaces varied between studies. A meta-analysis was not feasible due to the heterogeneity among studies. Implant with rough surfaces were more favourable for plaque accumulation during short-term follow-up. On a long-term, turned implants surfaces were associated with more plaque and higher peri-implant bone loss. Peri-implant clinical parameters and survival rate for two implant surfaces was similar.

Conclusions

Within the limitations of the present study, rough implant surface does not seem to increase the incidence of peri-implantitis in comparison to turned implants surface.

Effects of modified abutment characteristics on peri-implant soft tissue health: A systematic review and meta-analysis

Objectives

The purpose of this systematic review was to evaluate the impact of the abutment characteristics on peri‐implant tissue health and to identify the most suitable material and surface characteristics.

Methods

A protocol was developed aimed to answer the following focused question: “Which is the effect of the modification of the abutment design in regard to the maintenance of the peri‐implant soft tissue health?” Further subanalysis aimed to investigate the impact of the abutment material, macroscopic design, surface topography and surface manipulation. Randomised controlled trials (RCTs) with a follow‐up of at least 6 months after implant loading were considered as inclusion criteria. Meta‐analyses were performed whenever possible.

Results

Nineteen final publications from thirteen investigations were included. The results from the meta‐analysis indicated that zirconia abutments (Zi) experienced less increase in BOP values over time [n = 3; WMD = −26.96; 95% CI (−45.00; −8.92); p = .003] and less plaque accumulation [n = 1; MD = −20.00; 95% CI (−41.47; 1.47); p = .068] when compared with titanium abutments (Ti). Bone loss was influenced by the method of abutment decontamination [n = 1; MD = −0.44; 95% CI (−0.65; −0.23); p < .001]. The rest of the studied outcomes did not show statistically significant differences.

Conclusions

The macroscopic design, the surface topography and the manipulation of the implant abutment did not have a significant influence on peri‐implant inflammation. In contrast, the abutment material demonstrated increased BOP values over time for Ti when compared to Zi abutments.

Turned versus anodised dental implants: a meta-analysis

The aim of this meta-analysis was to test the null hypothesis of no difference in the implant failure rates, marginal bone loss (MBL)and post-operative infection for patients being rehabilitated by turned versus anodised-surface implants, against the alternative hypothesis of a difference. An electronic search without time or language restrictions was undertaken in November 2015. Eligibility criteria included clinical human studies, either randomised or not. Thirty-eight publications were included. The results suggest a risk ratio of 2·82 (95% CI 1·95-4·06, P < 0·00001) for failure of turned implants, when compared to anodised-surface implants. Sensitivity analyses showed similar results when only the studies inserting implants in maxillae or mandibles were pooled. There were no statistically significant effects of turned implants on the MBL (mean difference-MD 0·02, 95%CI -0·16-0·20; P = 0·82) in comparison to anodised implants. The results of a meta-regression considering the follow-up period as a covariate suggested an increase of the MD with the increase in the follow-up time (MD increase 0·012 mm year(-1) ), however, without a statistical significance (P = 0·813). Due to lack of satisfactory information, meta-analysis for the outcome 'post-operative infection' was not performed. The results have to be interpreted with caution due to the presence of several confounding factors in the included studies.

Implants with an Oxidized Surface Placed Predominately in Soft Bone Quality and Subjected to Immediate Occlusal Loading: Results from an 11-Year Clinical Follow-Up

PURPOSE

The purpose of this clinical follow-up was to document the 11-year outcome of implants with a moderately rough oxidized surface subjected to immediate occlusal loading.

MATERIALS AND METHODS

Twenty-six of 38 patients enrolled in a 5-year prospective study were available for this follow-up analysis, with 33 restorations supported by 66 slightly tapered implants (Brånemark System MkIV, Nobel Biocare, Gothenburg, Sweden). The majority of implants were placed in posterior regions (88%) and into soft bone (76%). Parameters included cumulative survival rate (CSR), radiographic marginal bone level, bleeding on probing (BOP), intrasulcular counts of perio-pathogenic markers (DNA probes), and total bacterial load (TBL).

RESULTS

The CSR was 97.1% at 11.2 years mean follow-up. Mean marginal bone remodeling was 0.47 mm (SD 1.09, n = 65) from 1 year postplacement to 11-year follow-up. BOP was absent at most sites (63.6%). No statistically significant differences in TBL or perio-pathogenic marker species were observed at implants and teeth.

CONCLUSION

The results of the present follow-up show high long-term survival, stable marginal bone levels, and soft tissue outcomes of oxidized surface implants placed predominately in posterior regions and soft bone. The quantity and quality of intrasulcular microbiota were comparable at implants and teeth.

Interventions for replacing missing teeth: different types of dental implants

BACKGROUND

Dental implants are available in different materials, shapes and with different surface characteristics. In particular, numerous implant designs and surface modifications have been developed for improving clinical outcome. This is an update of a Cochrane review first published in 2002, and previously updated in 2003, 2005 and 2007.

OBJECTIVES

Primary: to compare the clinical effects of different root-formed osseointegrated dental implant types for replacing missing teeth for the following specific comparisons: implants with different surface preparations, but having similar shape and material; implants with different shapes, but having similar surface preparation and material; implants made of different materials, but having similar surface preparation and shape; different implant types differing in surface preparation, shape, material or a combination of these.Secondary: to compare turned and roughened dental implants for occurrence of early implant failure (before prosthetic loading) and occurrence of peri-implantitis.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Oral Health Group's Trials Register (to 17 January 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 12), MEDLINE via OVID (1946 to 17 January 2014) and EMBASE via OVID (1980 to 17 January 2014). We placed no restrictions on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included any randomised controlled trial (RCT) comparing osseointegrated dental implants of different materials, shapes and surface properties having a follow-up in function of at least one year. Outcome measures were success of the implants, radiographic peri-implant marginal bone levels changes and incidence of peri-implantitis.

DATA COLLECTION AND ANALYSIS

At least two review authors independently conducted screening, risk of bias assessment and data extraction of eligible trials in duplicate. We expressed results using fixed-effect models (if up to three studies were present in a meta-analysis) or random-effects models (when there were more than three studies) using mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI). We reported the following endpoints: one, three, five and 10 years after functional loading.

MAIN RESULTS

We identified 81 different RCTs. We included 27 of these RCTs, reporting results from 1512 participants and 3230 implants in the review. We compared 38 different implant types with a follow-up ranging from one to 10 years. All implants were made of commercially pure titanium or its alloys, and had different shapes and surface preparations. We judged two trials to be at low risk of bias, 10 to be at unclear risk of bias and 15 to be at high risk of bias. On a 'per participant' rather than 'per implant' basis, we found no significant differences between various implant types for implant failures. The only observed statistically significant difference for the primary objective regarded more peri-implant bone loss at Nobel Speedy Groovy implants when compared with NobelActive implants (MD -0.59 mm; 95% CI -0.74 to -0.44, different implant shapes). The only observed statistically significant difference for the secondary objective was that implants with turned (smoother) surfaces had a 20% reduction in risk to be affected by peri-implantitis than implants with rough surfaces three years after loading (RR 0.80; 95% CI 0.67 to 0.96). There was a tendency for implants with turned surfaces to fail early more often than implants with roughened surfaces.

AUTHORS' CONCLUSIONS

Based on the results of the included RCTs, we found no evidence showing that any particular type of dental implant had superior long-term success. There was limited evidence showing that implants with relatively smooth (turned) surfaces were less prone to lose bone due to chronic infection (peri-implantitis) than implants with much rougher surfaces (titanium-plasma-sprayed). These findings were based on several RCTs, often at high risk of bias, with few participants and relatively short follow-up periods.

Reasons for failures of oral implants

This study reviews the literature regarding the factors contributing to failures of dental implants. An electronic search was undertaken including papers from 2004 onwards. The titles and abstracts from these results were read to identify studies within the selection criteria. All reference lists of the selected studies were then hand-searched, this time without time restrictions. A narrative review discussed some findings from the first two parts where separate data from non-comparative studies may have indicated conclusions different from those possible to draw in the systematic analysis. It may be suggested that the following situations are correlated to increase the implant failure rate: a low insertion torque of implants that are planned to be immediately or early loaded, inexperienced surgeons inserting the implants, implant insertion in the maxilla, implant insertion in the posterior region of the jaws, implants in heavy smokers, implant insertion in bone qualities type III and IV, implant insertion in places with small bone volumes, use of shorter length implants, greater number of implants placed per patient, lack of initial implant stability, use of cylindrical (non-threaded) implants and prosthetic rehabilitation with implant-supported overdentures. Moreover, it may be suggested that the following situations may be correlated with an increase in the implant failure rate: use of the non-submerged technique, immediate loading, implant insertion in fresh extraction sockets, smaller diameter implants. Some recently published studies suggest that modern, moderately rough implants may present with similar results irrespective if placed in maxillas, in smoking patients or using only short implants.