###### Abstract  
Minimising marginal bone loss around dental implants is of paramount importance. The success of methods such as platform switching (PS) and laser-micro-texturing (LM) are well documented. Whether or not a combination of these designs will further improve outcomes has not been studied previously. Hence, this prospective, randomized controlled single-centre pilot study compared the clinical and microbiological outcomes of implants with both PS and LM (test) to implants with only LM (control). A test and control implant were placed in thirteen patients totalling 26 implants. The primary investigated outcome was marginal bone level (MBL); secondary outcomes were peri-implant probing depths (PPD), bleeding on probing (BOP) and marginal tissue height (MTH). Additionally, the presence of five putative periodontal pathogens were assessed using real-time polymerized chain reaction. At 12 months the overall implant survival rate was 95.8%. MBL change was not found to be different between test and control at any time points, but a significant change was detected within the test implants at 6 months compared to baseline (\(p\) = 0.006). No differences were found in the secondary outcomes. Average PPD at 12 months was 2.68 \(\pm\) 0.73 mm and 2.30 \(\pm\) 0.46 mm and average change in MTH was 0.05 \(\pm\) 0.72 mm and \(-0.24\pm 0.59\) mm at tests and controls. No differences were reported in BOP frequency. Total periodontal pathogens count revealed no significant difference among control, test implants and adjacent tooth sites. Within the limitations of this study, it can be concluded that the addition of PS to LM implants does not significantly alter either short-term clinical outcomes or the vulnerability to pathogenic microflora colonization. b 2021 28 April 2021 28 April  
anatomy of the peri-implant tissues [2], clinical decisions [3; 4; 5; 6], operator experience [7] and implant designs [8; 9] may influence the marginal tissue stability. Among the implant design alterations aiming to reduce marginal remodelling are platform switching (PS) [10] and laser micro-texturing (LM) [11]. Both these technologies have shown promise in stabilisingperi-implant tissues. PS is a commonly used design to reduce marginal bone remodelling. It involves a \"mis-match\" of the abutment platform to the underlying implant restorative platform, where the abutment platform is reduced in circumference. This design is thought to reduce the crestal bone remodelling through a manipulation of the biological width or by moving the \"micro-gap\" at the implant abutment interface. The latter may reduce microbial irritation to the tissues. A recent systematic review did not find differences in marginal bone loss around PS and tissue level implants [12]. This hypothetical benefit was originally reported by [PERSON] and [PERSON] in 2006 [13] in a case series with a 13-year follow up. This technique has subsequently been adopted by many mainstream implant brands with varying interpretations regarding the magnitude of mismatch. This has also been followed by a plethora of clinical evidence for its utility [14; 15; 16; 17; 18; 19; 20]. Indeed, [PERSON] et al. [21] conducted a randomised controlled trial which involved 800 implants with varied degrees of platform mismatch. At 21 months, the control group with no platform mismatch was found to have an average of 1.49 mm crestal bone loss; the PS groups were found to have 0.99 mm, 0.82 mm and 0.56 mm of crestal bone loss depending on the degree of platform mismatch. This study concluded that the PS concept did maintain crestal bone levels and that this was also determined by the degree of PS. Furthermore, a systematic review by [PERSON] et al. 2015 [22], including 28 studies, reported that with longer observation periods a greater difference between the PS and regular groups was noted.