Stage 4 – Surgical procedure
Surgery was performed under local anesthesia [Fig. 10](11) and inhalation sedation with permanent monitoring of vital functions, after a complete pre-opperative evaluation by the AIC (anesthesia and intensiv care) doctor. The patient was instructed to administer himself orally amoxicillin 875 mg + clavulanic acid 125 mg every 12 hours for two days prior to surgery.
A crestal incision was performed from tuberosity to tuberosity, with one relieving incision in the midline. Buccal and palatal flaps were raised, exposing the anterior nasal spine, the pyriform apertures, the canine fossae, the zygomatic buttresses and the posterolateral maxillae. Drawing the incision line must be done with a firm movement (for a good elevation of the mucoperiosteum), thus offering increased comfort to the clinician during the medical procedure, by the fact that the bleeding is minimal, a good post-operative healing is ensured (dehiscences are avoided, which at least in the case subperiosteal implant represents an element that can compromise its integrity).
In cases with severe bone atrophy, we can meet two types of mucosae: 1) residual hypertrophic mucosa, with low resilience, very loose, which must be adjusted intraoperatively becuase it has poor vascularity and is very reactive or 2) residual thin mucosa, which can cause difficulties in rounding the edges of the wound. In this case, the mucosae has been reduced during surgery.
The next step after elevating the flap is represented by the placement of the implant itself, after this was removed from the sterile storage box [Fig. 13](11). The implant has a position of maximum intimacy with the residual alveolar bone, intimacy that must be followed, identified and exploited.
The first ostheosynthesis screws that are fixed are those at the extremities of the implant. The initial tightening is not definitive, but gradually, manually.
The flap was closed through multiple single knot ties [Fig. 16](11) done with a synthetic suture, manufactured by polymerising propylene [Fig. 15] (10). The suture is hydrophobic, it absorbs practically no water and is chemically inert. It ensures excellent know security and has a consistently high tear resistence, property which helps us prevent the dehiscences. It is ideal for skin or mucosa suture, where an excellent cosmetic result is critical (6).
Prosthetic impressions were taken immediately after closure, and prosthesis was successfully adapted in the same day, prior to patient discharge. Patient’s old removable denture was used as a provisional, and was padded in office. Thus, the patient being used to it, a much easier transition was endured. After it has been adapted and the abutments were placed, the denture was temporarilly cemented.
Discussion
In the last decades, although a decrease in the number of edentulous patients could be observed, their number still remains high, and with the increase in life expectancy, their need to replace lost teeth also rises. Furthermore, studies show that 1 out of 5 seniors aged 65 or more lost all his teeth. These being said, clinicians must offer viable treatment solutions to patients’ problems.
Endosseous implants have been and still are a suitable solution for those missing teeth, but unfortunatelly in cases with severe bone atrophy they have their limitations. As an alternative, more that 50 years ago, the subperiosteal implant was designed to fulfill this acute need for bone support and has been used ever since. However, the subperiosteal implants were soon surrounded by multiple complications such as implant exposure/woond dehiscences, implant mobility/implant loss, lack of intimacy with the bone due to impression material instability, and of course their popularity decreased. Recently, dentistry has been going through a digital revolution. It’s all about digital acquisition, better software, and more advanced fabrication. It’s the start of a whole new world of fixed prosthetics, including custom implant therapy.
In their study, Cerea and Dolcini described a group of 70 patients who had received custom-made titanium subperiosteal implants made using direct metal laser sintering (DMLS), which demonstrated a survival rate of 95.8% and low complication rates over a 2-year follow-up period. They came to the conclusion that when endosseous implants could not be placed, custom-made DMLS subperiosteal implants could offer a viable alternative treatment method for prosthetic restoration of severely atrophic jaws (7,8).
Conclusion
Althought subperiosteal implants are no longer the only option to restore atrophic jaws, they still remain a less invasive solution. Their high success rates and predictability remain undisputed advantages and, along with the technological evolution and the imprint left by the digital revolution even the worst disadvantages are losing ground, so that the treatment period was reduced from two surgical interventions to only one and thus the physical trauma inflicted on the patient is minimal. By using digital technology, the clinician has the opportunity to foresee the final result of the treatment plan, to realize the design of the future implant based on a 3D model of the patient’s anatomy, thus reducing almost to a minimum the possibility of error in execution. The important aspects that the clinician must continue to pay attention to are the healing stage and the complications associated with subperiosteal implants: dehiscences, implant mobility, framework fracture. These being said, the clinician’s skills to propose, design and place a subperiosteal implant remain and for sure will be an important asses in any ideal treatment plan.
References
  1. Ioan Sîrbu, DDS (DMSc); Subperiosteal Implant Technology: Report from Rumania . J Oral Implantol 1 August 2003; 29 (4): 189–194
  2. Garrido-Martínez P, Quispe-López N, Montesdeoca-García N, Esparza-Gómez G, Cebrián-Carretero JL. Maxillary reconstruction with subperiosteal implants in a cancer patient: A one-year follow-up. J Clin Exp Dent. 2022 Mar 1;14(3):e293-e297. doi: 10.4317/jced.59331. PMID: 35317297; PMCID: PMC8916599.
  3. Lopes LF, da Silva VF, Santiago JF Jr, Panzarini SR, Pellizzer EP. Placement of dental implants in the maxillary tuberosity: a systematic review. Int J Oral Maxillofac Surg. 2015 Feb;44(2):229-38. doi: 10.1016/j.ijom.2014.08.005. Epub 2014 Sep 26. PMID: 25260833.
  4. https://www.treatstock.co.uk/machines/item/220-eosint-m-280 accesat: 02.10.2023
  5. Resnik R. Misch’s Contemporary Implant Dentistry . 4th ed. St. Louis: Mosby; 2021
  6. https://www.resorba.com/ accesat: 09.10.2023
  7. Ângelo DF, Vieira Ferreira JR. The Role of Custom-made Subperiosteal Implants for Rehabilitation of Atrophic Jaws - A Case Report. Ann Maxillofac Surg. 2020 Jul-Dec;10(2):507-511. doi: 10.4103/ams.ams_263_20. Epub 2020 Dec 23. PMID: 33708606; PMCID: PMC7943994.
  8. Cerea M, Dolcini GA. Custom-made direct metal laser sintering titanium subperiosteal implants: A retrospective clinical study on 70 patients. BioMed Res Int.  2018;2018:11
  9. Link: https://www.ab-dent.com/u-product/
  10. Link: https://resorba.com/region/row/product/sutures/mopylen-cv/
  11. Courtesy of Prof. Ioan Sirbu, surgery day.
  12. Dicom images from the CBCT of the pacient realized one month before the surgery
  13. STL images from AB Dental International design of the future implant