Clinical outcomes of flap versus flapless immediately loaded single dental implants in the mandibular posterior region: One-year follow-up results from a randomized controlled trial

Flapless implant placement with immediate functional loading has been reported in anterior locations. However, data on posterior locations are lacking. The purpose of this randomized controlled trial was to determine and compare clinical outcomes of flap versus flapless surgically placed single posterior mandibular dental implants subjected to immediate functional loading. Participants with missing mandibular first molar teeth were recruited and randomized into 2 groups (n=51): flapped and flapless. Dental implants were surgically placed and loaded immediately with interim restorations following implant protective occlusion. Outcome measures were implant failure, crestal bone loss, and periodontal parameters: modified plaque index, modified sulcus bleeding index, and pocket depths. Outcome data were recorded at baseline, 6-month, and 12-month follow-up visits. Cone beam computed tomography scans were used to calculate crestal bone loss, and periodontal outcomes were recorded by using a resin covered periodontal probe (α=.05). After 12 months, similar implant failure rates (P>.05) were found between the groups. Crestal bone loss in the flapped group was statistically higher than in the flapless group at 6 months (0.83 ±0.21 mm versus 0.75 ±0.23 mm) and at 12 months (1.04 ±0.27 mm versus 0.90 ±0.24 mm) from the baseline. The modified plaque index, modified sulcus bleeding index, and peri-implant probing depths (PDs) in both groups increased from the baseline to 6-month follow-ups (Baseline modified plaque index: 0.82 ±0.54 versus 0.79 ±0.21; Baseline modified sulcus bleeding index: 0.74 ±0.21 versus 0.70 ±0.43; Baseline PD: 1.25 ±0.37 mm versus 1.20 ±0.22 mm; 6 months modified plaque index: 1.54 ±0.70 versus 1.21 ±0.45; 6 months modified sulcus bleeding index: 1.93 ±0.54 versus 1.51 ±0.61; 6 months PD: 3.20 ±0.73 mm versus 2.80 ±0.43 mm). At 12-month follow-ups after repeated oral hygiene reinforcements, periodontal parameters had improved (decreased) significantly. Flapless implant insertion with immediate functional loading could be considered as an appropriate treatment option for providing functional restorations on the day of implant placement with minimal surgical intervention, reducing crestal bone loss, and periodontal complications.