(34) Rehabilitation of the Severely Atrophied Maxilla: Diverse Indications and Treatment Protocols Using Zygomatic Implants, Standard Implants, and Bone Grafting Techniques.

Abstract: The atrophic maxilla is difficult to treat using conventional implant and bone grafting techniques. Zygomatic implants have been a predictable technique to reconstruct the atrophic maxilla. There are multiple treatment combinations that include zygomatic implants, standard implants, and bone grafting; but these have seldomly been described together in the literature.

A retrospective chart review was completed to identify patients that have undergone zygomatic implant placement. Variables included number of zygomatic and standard dental implants, unilateral vs bilateral placement, bone grafting status, osseointegration, hardware complications, smoking status, radiation treatment, infection, and prosthetic rehabilitation. Patients were followed at 6 and 12 months to evaluate abutment fractures, screw loosening, implant hygiene, and soft tissue complications.

We performed a retrospective review of accessible patient charts treated by a single surgeon between 2009-2022, and our data analysis was limited to descriptive statistics.

Twenty-two cases of zygomatic implants were used for maxillary reconstruction. A total of 49 zygomatic implants and 36 standard dental implants were placed. Indications included atrophic maxilla, cleft lip and palate, ectodermal dysplasia, and maxillectomy defect. Different permutations of reconstruction included 6 unilateral zygoma implants with anterior dental implant(s), 2 unilateral zygoma implants for maxillectomy reconstruction, 1 unilateral zygomatic implant with anterior iliac crest bone graft (AICBG) followed by dental implants, 6 bilateral zygomatic implants with anterior maxillary AICBG followed by dental implants, 15 bilateral zygoma implants with anterior dental implants, 3 bilateral zygoma implants without need of additional anterior dental implants, and 4 quad zygomas.

Mean age was 62 years; which included 7 males and 15 females. Success rate for zygoma and dental implants was defined as osseointegration with either delayed or immediate load for prosthetic rehabilitation. Success rate was 100 % for quad zygoma; 100% for unilateral zygomatic implants with additional pre-maxillary implants; 100 % for unilateral zygoma as distal extension of implant supported prosthesis; and 100% for bilateral single zygoma with additional pre-maxillary implants. Success rate for dental implants placed in native maxillary bone without grafting was 96% and 100% for dental implants placed after AICBG. 45 % of the cases were loaded in immediate fashion. All quad zygomas or zygoma implant with immediate standard anterior implant were loaded immediately while all cases involving bone graft to the anterior maxilla were delayed. Complications included one case of sinusitis and buccal dehiscence at level of zygomatic implant platform and a second case where the orbit was entered with subsequent conjunctival laceration.

Maxillary defect classification included ZAGA 0 (5), ZAGA 1 (1), ZAGA 2 (4), ZAGA 3 (3), ZAGA 4 (9). For maxillectomy defects the Brown classification was used; 3 patients had 2B defects. 7 patients had AICBG to anterior maxilla. 3 of 22 patients underwent radiation therapy that involved the maxilla. 36% of patients had history of smoking at time of surgery.

Out of 85 implants placed (49 zygomatic and 36 standard), 98.8% osseointegrated with subsequent use for prosthetic rehabilitation. 100 % of patients had at least one year of service with prosthesis.

In our experience, all methods described to reconstruct the maxilla using zygomatic implants have high predictability and success. Although literature shows that cross-arch stabilization using at least four zygomatic implants, with adequate anterior-posterior spread allows for effective axial loading, we have demonstrated other treatment permutations can also be viable rehabilitation that provides adequate support for prosthetic loading.

Andre A et al. Zygomatic Implants: A Review of a Treatment Alternative for the Severely Atrophic Maxilla. Atlas Oral Maxillofac Surg Clin North Am. 2021 Sep
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