Implant placement is a traumatic procedure, resulting in postoperative inflammation and bone resorption. The well-documented correlation between flap elevation and bone loss (Kohler & Ramfjord 1960; Lobene & Glickman 1963; Caffesse et al. 1968; Wood et al. 1972) resulted in the introduction of minimally invasive or flapless techniques, an approach that is gaining popularity in implant dentistry. Flapless implant placement can be performed by minimum incision (Jeong et al. 2007; Sunitha et al. 2008), immediate perforation with the drill through the soft tissues (Becker et al. 2005; Rao & Benzi 2007), computer guidance (Casap et al. 2005; Azari & Nikzad 2008), or soft tissue removal using a tissue punch (Hahn 2000; Cloyd 2009). Flapless implantation has several advantages such as decreased surgical time, maintenance of both soft and hard tissues, decreased postoperative bleeding, faster recovery, and patient’s comfort (Becker et al. 2005). On the other hand, significant disadvantages of flapless placement include the inability to visualize anatomic landmarks and vital structures, the potential for thermal osseous damage from the obstructed external irrigation, the inability to contour bone morphology, the increased risk of implant misplacement in relation to angulation or depth, keratinized gingival tissue loss, and the inability to manipulate soft tissues around emerging implant structures (Sclar 2007).

A total of 20 patients received 30 dental implants following a one-stage protocol. The patients were randomly assigned into two study groups: control group with 15 flapped implants and test group with 15 flapless implants. Follow-up examinations were carried out after 1, 2, 6, and 12 weeks. Clinical recordings, sulcular fluid sampling, microbiological analysis, and digital subtraction radiography were utilized to compare the two surgical approaches. Results: Peri-implant sulcus depth was significantly greater in flapped implants at both 6 and 12 postsurgical weeks (P < 0.001). Flapped implants showed crestal bone loss (0.29 ± 0.06 mm), whereas no bone resorption was detected around flapless implants. Matrix metalloproteinase-8 values were higher to a statistically significant level in the control group at 1 (P = 0.003) and 6 weeks (P = 0.007) after placement. In the test group, the presence of Porphyromonas gingivalis was significantly higher at the 2nd postoperative week (P = 0.005), whereas the counts of Tannerella forsythia were significantly elevated at the 1st (P = 0.005), 2nd (P = 0.001), and 12th (P = 0.002) postoperative weeks, possibly indicating an earlier formation and maturation of the peri-implant sulcus. Patients reported more pain after flapped implant placement.

The significant advantages and increasing popularity of flapless implantation resulted in a considerable number of clinical studies which mainly investigated clinical and radiographic parameters. The goal of the present prospective randomized clinical trial was to compare the placement of flapped vs. flapless dental implants utilizing in addition to custom clinical and radiographic outcomes, microbiological, immunological, and patient centered data. The results demonstrate that flapless implant placement yielded improved clinical, radiographic, and immunological outcomes compared with flapped implantation. The mean values of the investigated clinical parameters (mPLI, mGI and PD) were higher in the flapped compared with the flapless group at both follow-up evaluations, with statistically significant differences in PD and mGI at 6 and 12 weeks and for mPLI at 6 weeks (Table 2). Between the 6th and 12th postoperative weeks, mPLI and mGI were reduced, with the reduction of the mPLI being statistically significant. In agreement with these findings, You et al. (2009) in an experimental study showed that the flapped group had higher GI and bleeding on probing (BOP) compared with the flapless group (GI: 0.9 ± 0.5 and BOP: 0.7 ± 0.4 in the flapped group and zero values for both parameters in the flapless group), 3 months after implant placement.

The present prospective randomized controlled clinical trial compared flapped vs. flapless dental implantation procedures utilizing clinical, radiographic, microbiological, and immunological findings. The results indicated that implants placed with a flapless approach had decreased peri-implant sulcus depth values, a milder postsurgical inflammatory reaction, and no peri-implant bone. The present prospective randomized controlled clinical trial compared flapped vs. flapless dental implantation procedures utilizing clinical, radiographic, microbiological, and immunological findings. The results indicated that implants placed with a flapless approach had decreased peri-implant sulcus depth values, a milder postsurgical inflammatory reaction, and no peri-implant bone h implants placed with the conventional flap surgery. The elevated numbers of specific periodontal pathogens detected around flapless implants possibly indicated an earlier formation and maturation of the peri-implant sulcus in this group. Finally, flapless implantation caused less postoperative pain and was more easily tolerated by patients.

References 

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3. You, T.M., Choi, B.H., Li, J., Xuan, F., Jeong, S.M. & Jang, S.O. (2009) Morphogenesis of the periimplant mucosa: a comparison between flap and flapless procedures in the canine mandible. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics 107: 66–70.
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