Sandblasting reduces dental implant failure rate but not marginal bone level loss: A systematic review and meta-analysis

Introduction Sandblasting is one of the oldest implant surface modifications to enhance osseointegration. Regarding its superiority over machined surface controversies still exist. Our objective was to compare implant failures (IF) and marginal bone level (MBL) changes between sandblasted and machined dental implants by a meta-analysis utilizing the available data. The PROSPERO registration number of the meta-analysis is CRD42018084190. Methods The systematic search was performed in Cochrane, Embase and Pubmed. Inclusion criteria included participants with neither systemic diseases, nor excessive alcohol consumption, nor heavy smoking. We calculated pooled Risk Ratio (RRs) with confidence intervals of 95% (CIs) for dichotomous outcomes (implant failure) and weighted mean difference (WMD) CIs of 95% for continuous outcomes (marginal bone level change). We applied the random effect model with DerSimonian-Laird estimation. I2 and chi2 tests were used to quantify statistical heterogeneity and gain probability-values, respectively. Results Literature search revealed 130 records without duplicates. Out of these, seven studies met the inclusion criteria and all were included in data synthesis, involving 362 sand-blasted and 360 machined implants. The results indicate that there is an 80% (RR = 0.2 95% CI:0.06–0.67; I2 = 0.0% p = 0.986) lower among sandblasted compared to machined implants after one year of use and 74% (RR = 0.26 95% CI:0.09–0.74; I2 = 0.0% p = 0.968) five years of use, respectively. In contrast, there is no significant difference in MBL (WMD:-0.10mm, 95% CI:-0.20, 0.01; p>0.05; I2 = 0.0%, p = 0.560 and WMD:-0.01mm, 95% CI:-0.12, 0.09; p>0.05; I2 = 26.2%, p = 0.258) between the two implant surfaces after one and five years of use. Conclusions This meta-analysis reveals that sandblasting is superior over machined surface in implant failure but not in marginal bone level in healthy subjects. It also points out the need for further randomized clinical trials with large sample size for objective determination of the clinical benefits of certain implant surface modifications.

First author and title: Astrand, P. 2004 Astra Tech and Brånemark system implants: a 5-year prospective study of marginal bone reactions (The continuation of the study was published by Ravald et al. 2013 Long-term evaluation of Astra Tech and Brånemark implants in patients treated with full-arch bridges. Results after 12-15 years) Bias Authors judgement Support for judgement

Random sequence generation (selection bias)
Low risk Quote: "…patients were randomized in blocks with an equal probability of receiving Astra Tech or Brånemark system implants." Allocation concealment (selection bias)

Unclear
Comment: Not described.

Blinding of participants and personnel (performance bias)
High risk Comment: No blinding described, and probably no blinding occurred, due to the fact that different implant systems need different surgical protocols and special abutments for denture fixation thus study personnel must know the implant type.

Low risk
Quote: "A specialist in oral radiology, who did not take part in the clinical treatment, performed the radiographic evaluation."

Blinding of outcome assessment (detection bias) clinical outcome
High risk Comment: Probably no blinding due to the nature of outcome.

Incomplete outcome data (attrition bias)
Low risk Comment: 3 patients were excluded, one lost the implants (Brånemark), the other two died (Astra). However, all patients were included in the cumulative survival analysis.

Selective reporting (reporting bias)
Unclear risk Comment: No access to study protocol or trial registry entry, but no intext evidence of reporting bias.

Other bias
Low risk Comment: Study appears to be free of other sources of risk.

Random sequence generation (selection bias)
Low risk Quote: "A stratification and a randomization of the 2 surface groups were done. The first implants were selected at random by drawing lots…" Allocation concealment (selection bias)

High risk
Quote: "…thereafter the implants with different surface configurations were inserted alternately."

Blinding of participants and personnel (performance bias)
High risk Comment: No blinding described, and probably no blinding occurred, due to the fact that different implant systems need different surgical protocols and special abutments for denture fixation thus study personnel must know the implant type.

Low risk
Quote: "An experienced radiologist, not otherwise involved in the study, evaluated all the radiographs, blindly."

Blinding of outcome assessment (detection bias) clinical outcome
High risk Comment: No blinding described, due to the difference in characteristics of the two implant systems evaluators could differentiate between the two.

Low risk
Comment: 10 % of participants dropped out (eight from both implant types), otherwise no missing data.

Selective reporting (reporting bias)
Unclear risk Comment: No access to study protocol or trial registry entry, but no intext evidence of reporting bias.

Other bias
Low risk Comment: Study appears to be free of other sources of risk.

Random sequence generation (selection bias)
Unclear risk Quote: "…randomized for the jaw in which both implant systems were applied."

Allocation concealment (selection bias)
Unclear risk Comment: Way of randomization and allocation concealment are not described in the study.

Blinding of participants and personnel (performance bias)
High risk Comment: No blinding described, and probably no blinding occurred, due to the fact that different implant systems need different surgical protocols and special abutments for denture fixation thus study personnel must know the implant type.

Low risk
Comment: Blinding of outcome assessment not described but unlikely to affect measurement of this outcome.

Blinding of outcome assessment (detection bias) clinical outcome
High risk Comment: No blinding described, due to the difference in characteristics of the two implant systems evaluators could differentiate between the two.

Low risk
Comment: No drop outs.

Selective reporting (reporting bias)
Unclear risk Comment: No access to study protocol or trial registry entry, but no intext evidence of reporting bias.

Other bias
Low risk Comment: Study appears to be free of other sources of risk.
Article's first author and title: Tawse Unclear risk Quote: "participants were randomly selected from those requesting the placement of osseointegrated Implants…" Comment: However, the method for randomization is not described.

Allocation concealment (selection bias)
Unclear risk Comment: Selection method not described.

Blinding of participants and personnel (performance bias)
High risk Comment: No blinding described, and probably no blinding occurred, due to the fact that different implant systems need different surgical protocols and special abutments for denture fixation thus study personnel must know the implant type.

Low risk
Comment: Blinding of outcome assessment not described but unlikely to affect measurement of this outcome, "standardized intraoral radiographs" were used.

Blinding of outcome assessment (detection bias) clinical outcome
High risk Comment: No blinding described, due to the difference in characteristics of the two implant systems evaluators could differentiate between the two.

Incomplete outcome data (attrition bias)
Unclear risk Comment: Two participants dropped out, no reason was given.

Selective reporting (reporting bias)
Unclear risk Comment: No access to study protocol or trial registry entry, but no intext evidence of reporting bias.

Other bias
Low risk Comment: Study appears to be free of other sources of risk.