Published online Mar 26, 2020. doi: 10.12998/wjcc.v8.i6.1087
Peer-review started: October 21, 2019
First decision: November 11, 2019
Revised: November 13, 2019
Accepted: December 6, 2019
Article in press: December 6, 2019
Published online: March 26, 2020
Conventional implant surgery involves flap elevation, which may result in increased postoperative discomfort and morbidity. The flapless surgical technique, aided by three-dimensional medical imaging equipment, is regarded as a possible alternative to the conventional approach to alleviate the above issues. However, previous results regarding the role of flapless implant surgery are inconsistent and there is still concern regarding the long-term clinical performance of the flapless surgical technique. To date, no meta-analysis or systematic review comparing the long-term clinical performance of the flapless surgical technique to the conventional approach have been published.
The long-term clinical performance of dental implant treatment can be affected by different surgical techniques. Thus, it is important to compare the long-term outcomes of flapless implant surgery to those of the conventional approach over a follow-up of three years or more. A better insight into this topic would help inform surgeons regarding which type of surgical technique is more beneficial to the long-term prognosis of patients in need of implant insertion.
To compare the long-term clinical performance after flapless implant surgery to that after the conventional approach with flap elevation.
This was a systematic review and meta-analysis. The protocol of this study was defined by the authors prior to the literature search. Nine electronic databases were systematically searched from inception to September 23, 2019. A manual search was also carried out to identify studies that were not indexed in the above databases. Randomised controlled trials (RCTs) and cohort studies comparing the long-term clinical performance after flapless implant surgery to the conventional approach over a follow-up of three years or more were included in the current systematic review. The risk of bias in selected RCTs and cohort studies was assessed using the Cochrane Collaboration’s tool for assessing risk of bias and the Newcastle-Ottawa Scale, respectively. Meta-analyses were conducted to estimate the odds ratios (ORs) or mean differences (MDs) and their 95% confidence intervals (CIs) for the implant survival rate, marginal bone loss, and complication rate of the flapless and conventional groups. Sensitivity analyses were performed to determine if the findings of the current meta-analyses were dependent on any individual study. Moreover, subgroup analyses were carried out to account for the possible effects of the guided or free-hand method during flapless surgery.
Of 1839 records, ten articles (i.e., four RCTs and six cohort studies) involving a total of 8607 participants and 20428 implants satisfied the eligibility criteria and nine of them (i.e., four RCTs and five cohort studies) were included in the meta-analysis. Two RCTs (50%) were evaluated to have an unclear risk of bias and the other two RCTs (50%) were found to have a high risk of bias. Three cohort studies had a low risk of bias, and the other three cohort studies were judged to have a moderate risk of bias. After meta-analyses, there was no significant difference between the long-term implant survival rate [OR = 1.30, 95%CI (0.37, 4.54), P = 0.68], marginal bone loss [MD = 0.01, 95%CI (-0.42, 0.44), P = 0.97], and complication rate [OR = 1.44, 95%CI (0.77, 2.68), P = 0.25] between the flapless implant surgery group and the conventional approach group. The overall results and conclusions of the meta-analyses were not affected by the exclusion or inclusion of individual studies. Moreover, subgroup analyses revealed that there was no statistically significant difference between the implant survival rate [guided: OR = 1.52, 95%CI (0.19, 12.35), P = 0.70; free-hand: n = 1, could not be estimated], marginal bone loss [guided: MD = 0.22, 95%CI (-0.14, 0.59), P = 0.23; free-hand: MD = -0.27, 95%CI (-1.10, 0.57), P = 0.53], or complication rate [guided: OR = 1.16, 95%CI (0.52, 2.63), P = 0.71; free-hand: OR = 1.75, 95%CI (0.66, 4.63), P = 0.26] in the flapless and conventional groups either with the use of a surgical guide or by the free-hand method.
These findings indicated that flapless surgery and the conventional approach have comparable clinical performance over a long-term follow-up of three years or more. The guided or free-hand technique does not significantly affect the long-term effects of flapless surgery. Hence, the flapless technique is considered a promising alternative to the conventional implant approach without significantly compromising the long-term outcomes of implant treatment.
The overall results of long-term clinical performance after flapless implant surgery are acceptable. These findings provide surgeons with evidence-based practical insight that the flapless technique can be considered an alternative to the conventional implant approach in patients with appropriate alveolar bone and soft tissue conditions. Although evidence from the study suggests that guided or free-hand implant insertion does not significantly affect the long-term outcomes of flapless implant surgery, surgeons' experience and relevant cost-effectiveness should be considered regarding the option of a surgical guide or free-hand method in flapless surgery. Further high-quality RCTs with a long-term follow-up are needed for a more robust assessment.