Ethical aspects

This retrospective case series was approved by the local Research Ethics Committee (CAAE 98088718.5.0000.0093). Patients were informed of the nature of the study and procedures, according to the Free and Informed Consent Term. Additionally, this study followed the Helsinki guidelines [19].

Study design

Twelve adult patients of both sexes were evaluated. They were users of total prostheses on totally edentulous maxillae with severe resorption, which prevented the placement of conventional implants between the canine and maxillary tuberosity.

These patients had good health conditions and psychological disposition to undergo common oral surgery procedures under local anesthesia, in addition to the clinical procedures necessary for the fabrication of prostheses. Such patients underwent (1) preoperative examination for planning, (2) transmaxillary implant placement with or without using the homologous bone (used for grafting in the maxillary sinus, simultaneously with the implant placement, when necessary), and (3) prosthetic rehabilitation after the period of osseointegration of the implants (6 months).

Patients, who demonstrated the presence of systemic pathologies (hematological, diabetes, autoimmune diseases), infections, or apparent inflammation in the oral cavity, maxillary sinuses, or any region of the stomatognathic system, were excluded. Patients, who used bisphosphonates and who underwent the head and neck irradiation in a period of 60 months before this study, were also eliminated. Smokers, patients with bruxism or severe jaw tightening, those with poor oral hygiene, and those who were unable to assume the costs of homologous bone or prosthetic rehabilitation after implant osseointegration were also excluded.

The procedures were performed during a period of 5 years (considering the date of the first appointment and the evaluation of the last image). Surgical guides and bio-models (three-dimensional printing) were prepared for the placement of transmaxillary implants (Kopp, Curitiba, Paraná, Brazil) horizontally (Fig. 1). The patients underwent transmaxillary implant placement and prosthesis delivery at the clinic of Instituto Kopp, Curitiba, Paraná, Brazil. The prostheses received immediate loading or late loading, depending on local and surgical conditions. In the pre- and postoperative evaluations, all patients were assessed for OHRQoL using the OHIP-14 questionnaire.