<div>Additively Custom-made 3D Printed Subperiosteal Implants for the
rehabilitation of the Severely Atrophic Maxilla (a case report)</div><div>Mahnaz Arshad, D.D.S.<sup>a</sup> , Nourin Khoramshahi,
D.D.S.<sup>b</sup> , Gholamreza Shirani, D.D.S.,
MD<sup>c</sup>.</div><div>a Associate Professor, Department of Prosthodontics, School of
Dentistry, International Campus, Tehran University of Medical Sciences,
Tehran, Iran.</div><div>b D.D.S., School of Dentistry, International Campus, Tehran University
of Medical Sciences, Tehran, Iran.</div><div>c Associate Professor, Department of Oral and Maxillofacial Surgery,
School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran</div><div>Corresponding Author:</div><div>Nourin Khoramshahi, D.D.S.</div><div>School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran</div><div>Address: Farhikhtegan Tower, Dr. Khoramshahi St., Kuhak Blvd, Tehran,
Iran</div><div>Tel: +989102018828</div><div>Fax: +982146147212</div><div>Email: khrmshh@gmail.com</div><div>ORCID:</div><div>Mahnaz Arshad: 0000-0002-6278-6278</div><div>Nourin Khoramshahi: 0000-0002-6547-0877</div><div>Gholamreza Shirani: 0000-0002-6229-1320</div><div>All authors declare that there was no competing interest. The authors
have no relevant financial or non-financial interests to disclose. The
authors did not receive support from any organization for the submitted
work. The patient has signed informed consent before each treatment
procedure. As a result of this transfer, we assign, or otherwise convey
all copyright ownership, including any rights incidental to it,
exclusively to the journal if the journal publishes such work. Also, we
hereby declare that non of the authors listed on the manuscript are
employed by a government agency that has a primary function other than
research and/or education and non of the authors are submitting this
manuscript as an official representative or on behalf of the government.
Additional data may be translated from persian and presented by the
correspond author upon reasonable request.</div><div>Abstract word count: 49</div><div>Manuscript word count: 1537</div><div>Number of figures: 11</div><div>Key Clinical Message</div><div>Subperiosteal implants might be the future first-line treatment in
patients with compromised alveolar ridges, although the use of proper
techniques and pre-surgical imaging is required to ensure treatment
success.</div><div>Abstract</div><div>In the past decade, on account of computer-aided prosthetic
manufacturing techniques, subperiosteal implants were introduced as a
safe option for patients with compromised alveolar ridges. We present 3
years follow-up of a complete maxillary rehabilitation by subperiosteal
implants in a young patient after an endosseous implant treatment
failure.</div><div>Keywords: Subperiosteal Dental Implantation, Alveolar Bone Loss, Bone
Resorption, Endosseous Dental Implantation, Aggressive Periodontitis</div><div>Introduction</div><div>Dental endosseous implants are a favorable replacement for teeth in many
cases. They offer a high success rate and predictable results. Some
studies report that endosseous dental implants’ success rate might rise
to 89-99% (1). However, endosseous implants require a certain amount of
bone quantity and quality to succeed, and their ideal requirements are
not always available. In complicated cases where the alveolar bone is
resorbed or compromised, the endosseous implantation procedure becomes
challenging (2). Several strategies have been suggested aiming to induce
bone regeneration. However, each method comes with many additional risks
and complications. Bone grafts are the most adopted strategy to replace
the resorbed alveolar bone. However, this treatment has many downsides,
such as its complexity, long healing period, increased risk of
complications, patient discomfort in extra-oral grafts, and limited bone
supply in intra-oral grafts (3, 4).</div><div>Subperiosteal implants (S.P.I.s) were first introduced in the 1940s but
were soon eliminated due to prevalent complications. The first models of
subperiosteal implants were custom-made cobalt-chrome or titanium
implants placed below the periosteum and held the prosthesis in place.
These implants lacked adequate fitting and often caused peri-implantitis
by implant movements (1, 5).</div><div>In the past decade, the concept of sub-periosteal implants has reemerged
with the evolving digital technologies used in dental prostheses
fabrications. Using additive manufacturing technology in S.P.I.
fabrication has led to a better fitting and, therefore, a high level of
bone to implant contact, which reduced implant failures dramatically (2,
5).</div><div>In this article, we present a case of S.P.I. in the maxillary after the
failure of endosseous implant-supported prostheses. So a unique
subperiosteal implant with abutments connected to the body of S.P.I. was
designed.</div><div>Case report</div><div>In 2018 a maxillary edentulous 25-yrs-old male patient was referred to
the prosthodontic department of Tehran University of Medical Sciences.
His chief complaint was extreme dissatisfaction with appearance,
mastication, and speech. A detailed medical, dental and social history
was obtained. The medical history and general physical condition were
unremarkable. Dental history showed that the patient lost his teeth six
years ago because of aggressive periodontitis and received dental
rehabilitation by implant-supported full mouth prosthesis, but, after
five years, all maxillary implants failed (Figures 1a, b and c).
Therefore, he requested full mouth dental replacement.</div><div>The clinical and radiographic examination revealed that the previous
implant failure had caused severe alveolar resorption, and the patient
lost a large amount of bone volume (Figure 2). Thus, placing endosseous
implants again was not possible.</div><div>Bone graft surgery requires a prolonged healing period added to the
waiting period in the implant treatments. The patient was young, and
this delay might affect his social and psychological health. Considering
the risk of complications followed by extensive bone graft and the
unpredictable prognosis of this strategy, we decided to perform S.P.I.
reconstruction in the maxilla (Figure 2).</div><div>To achieve the best function and aesthetic possible, first, we obtained
the primary impressions from both jaws using a prefabricated tray and
irreversible hydrocolloid material (Alginate, Zhermack, Badia Polesine
(R.O.), Italy). a special tray was fabricated by auto-polymerizing
acrylic resin and border molded using a green modeling plastic
impression compound (Kerr Corp., Bioggio, Switzerland) to achieve a more
accurate final impression. The final impression was obtained using zinc
oxide eugenol paste (Luralite, Kerr, U.S.A.). A maxillary record base
and a wax rim were fabricated. Jaws relationship was registered then the
Maxillary cast was mounted using an arbitrary face bow (Dentatus,
Dentatus Ltd., NY) on a semi-adjustable articulator (Dentatus A.R.H.,
Dentatus Ltd., NY). The mandibular cast was connected to the maxilla
using a centric relation record. Anterior tooth set-up
(Vivotac/Orthotak, Ivoclar Vivadent, Schaan, Liechtenstein) was
accomplished on the mounted casts, and a diagnostic tooth set-up was
performed and tried in. The acrylic teeth were poured with barium
sulfate (Foshan Xinmei Chemical, Guangdong, China) containing acrylic
resin. This made the teeth opaque so that the occlusal plane and
longitudinal axis of teeth could be detected in the 3D-C.T. scan to
determine the proper location of abutments on S.P.I., The center of the
posterior teeth and the cingulum of anterior teeth to the crest of the
maxillary ridge were perforated with fissure tungsten laboratory bur to
make the lucency in the C.T. scan to determine the longitudinal axis of
final implant abutments (Figures 3 a, b, c, d).</div><div>With the consult of the prosthodontist, the engineer designed the S.P.I.
Therefore a 3D model based on the patient’s C.T. was generated to assess
the optimum S.P.I. design and positioning. After carefully planning the
implants’ placement, we fabricated the S.P.I. using the Additive
Manufacturing technique by Titanium alloy grade 23 (Ti6AL4V-ELI, Bonash
Company, Iran) (Figure 4). The critical point of this design was that
because the abutment was connected to the body and it was impossible to
change the abutment angles, the abutment angles were designed very
precisely using 3D C.T. using a radiographic stent. After manufacturing
the S.P.I., it was screwed into a printed skull, and the prosthodontist
checked the interocclusal clearance and abutments angles and positions
(Figure 4). Then it was scanned, and STL data was sent to the
laboratory. Then S.P.I. was sent to the cleaning room and sterilized
with an autoclave. The patient underwent surgery with general anesthesia
to place the S.P.I (Figures 5 a and b).</div><div>After two weeks, a temporary implant-supported bridge was delivered to
the patient (Figure 6). They were cemented with temporary cement (Temp
bond, Kerr, U.S.A.) (Figure 7a and b). Minor dehiscence was found in the
left premolar area of the maxilla (Figure 8a and b). However, this
dehiscence did not extend in the following sessions. Three months later,
the three-part full ceramic CAD/CAM bridges with BL4 shade for the
maxilla were fabricated based on the scanned data (Figure 9). Crowns
were tried in the mouth, and the fit of frames was checked. The teeth
were adjusted to achieve group function occlusion. Implant-supported
crowns were cemented with temporary cement (TEMP Bond, Kerr, U.S.A.)
(Figure 10). We scheduled follow-up sessions post-delivery, and the
patient was instructed to a careful oral hygiene routine consisting of
waterjet, teeth brushing, and super floss. The patient was satisfied
with the results during the three-year follow-up (Figure 11).</div><div>Discussion</div><div>Since the 1980s, dental endosseous implants have become one of the most
common replacements for teeth (1). However, the need for adequate bone
quality and quantity is not always met. On the other hand, reports show
that bone resorption continues post-implantation, which endangers the
implant condition, and represents a significant challenge for future
treatment. Dental rehabilitation of a resorbed alveolar ridge,
regardless of the cause, requires a complicated course of treatment and
is challenging. Bone grafts are the most common bone replacement in such
cases. However, bone grafts need a long healing period and have
unpredictable results (3, 6). Also, they might cause significant
complications. For instance, a study reports that neural complications
related to an intra-oral bone graft strategy may rise to 50% (7).</div><div>Recent advancements in dental prostheses have allowed us to revisit
older treatments with reduced complication risk. The S.P.I.s are
considered to be a replacement for different types of bone grafting and
other strategies applied on a compromised ridge. With the latest
accomplishments in the field of prostheses manufacturing, we have
overcome most of the previous complications (2, 5).</div><div>In this report, we explained the steps and strategies applied to
fabricate and deliver an S.P.I. for our patient. The patient had lost
his teeth at quite a young age due to aggressive periodontitis and
received dental endosseous implants as a replacement. Unfortunately,
after five years, the prosthesis and implants were explanted, leaving
him in need of another treatment course. This time, the maxillary
alveolar ridge was severely resorbed, and he was no longer a candidate
for endosseous implants. Therefore, we decided to use an S.P.I. for full
mouth rehabilitation. Our 3years follow-up shows that the S.P.I. is in
excellent condition, and the patient is satisfied with the results.</div><div>The results of a retrospective study on 70 patients with S.P.I.s show
that after 2years of follow-up, the survival rate of S.P.I.s was
approximately 96%. In the study, the authors report that only three of
the S.P.I.s failed due to untreatable recurrent infection. (8)</div><div>In a more recent case series study, the survival rate of 10 S.P.I.s in
partially edentulous patients was 100% after 12 months of follow-up.
However, one S.P.I. had a minor immediate post-operative complication
managed successfully by antibiotics and pain-relievers. The authors
believe that the accurate fit of the S.P.I.s was the main reason for the
low incidence of complications resulting in a high survival rate. (9)</div><div>The S.P.I.s have reemerged, especially during the last decade, and
reports of successful S.P.I. dental rehabilitations are increasing
thanks to the new manufacturing techniques. (2) Nevertheless,
underestimating the importance of different procedure steps may cause
many complications and may eventually lead to implant failure. For
instance, using a radiographic stent based on a provisional dental
setting helps determine the perfect design and angulation for the
attachments.</div><div>Authorship</div><div>M.A.: involved in the study conception and design, material preparation,
prosthodontic treatment of the patient, and revised the manuscript;
N.K.: involved in material preparation, drafted and revised the
manuscript; G.S.: involved in the study conception and design, material
preparation, and surgical treatment of the patient.</div><div>Acknowledgments</div><div>The authors thank BONASH (Tehran, Iran) for manufacturing the
subperiosteal implant.</div><div>Conflict of interest</div><div>All the authors of this report wish to disclose that there are no
financial or other conflicts of interest that might have biased the
scientific information in this article.</div><div>Patient consent</div><div>The patient has signed an informed written consent form for publishing
this report. The consent form was translated to persian based on the
journal’s patient consent policies.</div><div>Abbreviation</div><div>S.P.I: Subperiosteal implants</div><div>C.T.: Computed tomography</div><div>CAD/CAM: Computer-Aided Design / Computer-Aided Manufacturing</div><div>References</div><div>1. W Nicholson J. Titanium alloys for dental implants: A review.
Prosthesis. 2020;2(2):100-16.</div><div>2. Mommaerts M. Evolutionary steps in the design and
biofunctionalization of the additively manufactured sub-periosteal jaw
implant ‘AMSJI’for the maxilla. International Journal of Oral and
Maxillofacial Surgery. 2019;48(1):108-14.</div><div>3. Chiapasco M, Tommasato G, Palombo D, Scarnò D, Zaniboni M, Del Fabbro
M. Dental implants placed in severely atrophic jaws reconstructed with
autogenous calvarium, bovine bone mineral, and collagen membranes: A
3‐to 19‐year retrospective follow‐up study. Clinical Oral Implants
Research. 2018;29(7):725-40.</div><div>4. Moy PK, Aghaloo T. Risk factors in bone augmentation procedures.
Periodontology 2000. 2019;81(1):76-90.</div><div>5. Garrido-Martínez P, Quispe-López N, Montesdeoca-García N,
Esparza-Gómez G, Cebrián-Carretero J-L. Maxillary reconstruction with
subperiosteal implants in a cancer patient: A one-year follow-up.
Journal of Clinical and Experimental Dentistry. 2022;14(3):e293.</div><div>6. Um I-W, Ku J-K, Kim Y-M, Yun P-Y, Chang N-H, Kim Y-K, et al.
Allogeneic demineralized dentin matrix graft for guided bone
regeneration in dental implants. Applied Sciences. 2020;10(13):4661.</div><div>7. Chiapasco M, Casentini P, Zaniboni M. Bone augmentation procedures in
implant dentistry. International Journal of Oral &amp; Maxillofacial
Implants. 2009;24.</div><div>8. Cerea M, Dolcini GA. Custom-made direct metal laser sintering
titanium subperiosteal implants: A retrospective clinical study on 70
patients. BioMed research international. 2018;2018.</div><div>9. Mangano C, Bianchi A, Mangano FG, Dana J, Colombo M, Solop I, et al.
Custom-made 3D printed subperiosteal titanium implants for the
prosthetic restoration of the atrophic posterior mandible of elderly
patients: a case series. 3D Printing in Medicine. 2020;6(1):1-14.</div><div>Figures</div><div>Figure 1. Different views of patient 1 year after the initial implants
failure. a: Frontal view, b: Occlusal view, c: Lateral view.</div><div>Figure 2. Panoramic radiography taken 1 year after the initial implants
failure.</div><div>Figure 3. Different views of subperiosteal implants’ 3D model design.</div><div>Figure 4. The fabricated S.P.I model screwed to a printed skull to
evaluate it.</div><div>Figure 5. After final confirmation of the implant, an oral surgery was
performed to place the implant.</div><div>Figure 6.Temporary prosthetic design based on 3D printed skull model.</div><div>Figure 7. The temporary prosthetic cemented in place.</div><div>Figure 8. A minor dehisence occurred in the left premolar area but did
not extend over time.</div><div>Figure 9. The prosthetic design.</div><div>Figure 10. Final prosthetic delivary.</div><div>Figure 11. Panoramic radiography showing implant status after 3 years.</div>