# Prosthodtic Considerations for Customized Subperiosteal Implants: A Consensus Report
## 3 Results
### Surgical Considerations  
1. Buccal fat pad flaps may be an interesting approach to treat complications and exposures of CSIs. However, their routine use to prevent soft tissue dehikerences is not recommended, since these complications are associated with the CSI design and the amount of keratinized mucosa, rather than with the thickness of the buccal flap [4].
2. An adequate thickness and width of keratinized mucosa is essential to avoid complications. Occasionally, soft tissue augmentation may be necessary prior to CSI placement. Proper soft tissue management is essential to avoid dehikerences [12; 13].
3. Dental extractions should be done prior to CSI placement to allow proper tissue healing. If this is not feasible, basic periodontal therapy should be applied to the remaining teeth to remove biofilm and reduce inflammation (EO).
4. The flap design should maximize the keratinized mucosa (EO). Distal vertical releasing incisions improve surgical access but should be placed far away from the posterior connections of the CSI [14].
5. The prosthetic connection areas should have adequate keratinized mucosa to prevent possible exposures of the CSI (EO).
6. The fixation screw protocol should be adapted according to the bone type involved. The fixation screw direction and primary stability are critical surgical factors (EO).
7. Fixation screws should be placed perpendicular to the bone and in the center of the CSI insertion hole, maintaining the planned direction (EO) (Figure 4).  
Figure 3: Maximly definite prosthesis made of polymethylmethacrylate (PMMA).  
Figure 2: Maximly CSI with transepithelial abutments. Laser sintering titanium Grade 23 (TfiA14V ELI alloy) with thickness of 0.8 mm using an EOS M290 printer. (Avinent, Santpedor, Spain).  
8. The working group recommends the use of self-drilling screws to avoid the use of drills, which may compromise screw stability in areas of alveolar bone in cases of grade V atrophy. In cortical bone areas, such as the nasal buttress and zygomatic bone, drilling prior to screw placement is recommended in order to avoid excessive insertion torque, screw head deformation and/or screw fracture. Depending on the surgeon's experience, the use of drills may be omitted in certain areas [2] (Figure 5).
9. The number of fixation screws should ensure adequate mechanical stability of the CSI. A minimum of two screws per fixation area (palatal, zygomatic or nasal) is recommended [14]. Since the stability of the CSI depends on the number and length of the screws, their placement in the fixation areas should be maximized. Fixation screws in areas close to the alveolar ridge may increase the risk of CSI exposure, since they affect the design of the implant [2] (Figure 6).
10. The use of a surgical cutting guide is essential in patients with grade V atrophy [5]. Placement of the CSI over the alveolar ridge should be avoided in order to minimize the presence of abrupt transitions, which are often associated with implant exposures. Titanium surgical cutting guides are rigid, thus providing greater precision and reducing the risk of particle release during the procedure. Other materials, such as a semirigid polyamide can be used, but further research is required to conduct a correct cost-effectiveness analysis (EO).