Reconstruction of vertical alveolar ridge deficiencies utilizing a high-density polytetrafluoroethylene membrane/clinical impact of flap dehiscence on treatment outcomes: case series

Palkovics D, Bolya-Orosz F, Pinter C, Molnar B, Windisch P. BMC Oral Health. 2022 Nov 15;22(1):490.


Eight patients requiring vertical ridge augmentation for an implant-supported rehabilitation in the mandible or maxilla were treated by a GBR approach in conjunction with a split-thickness flap. Following flap elevation, tenting screws for membrane support were inserted according to the desired bone height and permamem® was applied. The membrane was immobilized with titanium pins or membrane fixation screws on the palatal/lingual site and the defect was grafted with a mixture of cerabone® and autologous bone in the ratio 1:1. After grafting the membrane was folded over the heads of the tenting screws and secured on the buccal aspect. The wound was closed by suturing the periosteum and subsequently the mucosa.


  • Bone volume changes were analyzed using CBCT data recorded pre-operative and 9 months post-augmentation with the help of image segmentation and 3D radiographic subtraction analysis.
  • Effects of a secondary exposure of permamem® on the clinical outcome were assessed by comparing the bone volume changes of cases with and without exposure.


  • 4 cases each presented with and without membrane exposure
  • Average bone gain 9 months post-operative for all cases (n = 8): Volumetric: 0.76 ± 0.33 cm3, linear vertical: 3.80 ± 0.54 mm, linear horizontal: 5.75 ± 0.87 mm
  • For cases with membrane exposure 17%, 14% and 5% less volumetric, linear vertical and linear horizontal bone gain respectively in comparison to cases with submerged healing
  • No additional bone augmentation was necessary during reentry in any of the cases


  • Significant horizonto-vertical bone gain despite secondary exposure of permamem®
  • Gained bone volume allowed for placement of implants at 2nd stage surgery in all evaluated cases
  • Less bone loss in case of exposure of permamem® as compared to other membranes (Garcia et al. 2018, Machtei 2001)
  • Tent-pole technique with permamem® is a powerful method for the reconstruction of vertical bone defects