Anatomical analysis of zygomatic bone in ectodermal dysplasia patients with oligodontia

Abstract

Background Abnormalities of some facial bones derived from the ectomesenchyme have been found in ectodermal dysplasia (ED) patients, but the characteristics of the zygoma are unknown. Purpose Comparison between ED patients and normal individuals to understand the anatomical features of the zygoma in ED patients. Materials and Methods Thirty patients diagnosed with ED based on clinical features and/or gene sequence tests and 80 normal individuals were recruited from 2016 to 2018. The thickness of the zygomatic body at 12 points on the superior, middle, and inferior areas and the length of four lines were measured on a three‐dimensional cone beam computed tomography image. Differences between ED patients and normal individuals were then compared. Results The zygomatic thicknesses and lengths were smaller in ED patients than in normal individuals. For ED patients, the largest thicknesses on the superior, middle, and inferior areas of the zygoma were 8.47 ± 1.49, 7.03 ± 1.56, and 5.99 ± 1.22 mm. Conclusion The development of zygomatic thickness on the inferior area and the zygomatic length were insufficient in ED patients with oligodontia. Consequently, zygomatic hypoplasia presented difficulties for the “quad approach” to zygomatic implants in this group of patients.

The Scientific Context of Zygomatic Implant in Bone Loss: A Review.

“…Furthermore, the development of the zygomatic thickness in the inferior area and the zygomatic length were insufficient in patients with oligodontia. Consequently, zygomatic hypoplasia presented difficulties for the "quadruple approach" to ZI in this group of patients [5].…”

“…The amount of zygomatic bone is intrinsic to each patient. In this sense, the zygomatic has a compact and regular trabecular bone with 98.0% density [5][6][7][8][9]. The adequate occlusal stress caused by the forces is supported by the implant transferred mainly through the crest and below the zygomatic, divided into the zygomatic frontal and temporal bone [10].…”

“…Thus, the zygomatic implant (ZI) is an alternative when there is bone loss [5]. The ZI is long, threaded, oxidized and moderately rough, with lengths ranging from 30 to 52.5 mm.…”

“…The ZI is long, threaded, oxidized and moderately rough, with lengths ranging from 30 to 52.5 mm. They have a slanting head that is designed to allow placement of the prosthesis 45 along the axis of the implant, providing an excellent ability to retain, support and stabilize the prosthesis while minimizing leverage [5].…”

Zygomatic implant survival in 9 ectodermal dysplasia patients with 3.5‐ to 7‐year follow‐up

“…The possible complications of ZI surgery include sinusitis, soft tissue infections, paresthesia, and oroantral fistula, penetration of the orbital cavity during the drilling protocol, and failure of the implants (Filho, Amaral, Curra, dos Santos, & Cardoso, 2016;Maló, Nobre, Lopes, Ferro, & Moss, 2015;Nobre, Maló, & Gonçalves, 2015). (Wang et al, 2019).…”