In Focus: Monthly study highlights

1. Long-term survival and complications of Quad Zygoma Protocol with Anatomy-Guided Approach in severely atrophic maxilla: A retrospective follow-up analysis of up to 17 years.

Davó R, Fan S, Wang F, et al. Clin Implant Dent Relat Res. 2023 Dec 12. 

The objective of this retrospective cohort study, conducted by Dr. Ruben Davó et al. was to provide long-term clinical outcomes and complications in the severely atrophic edentulous maxillae treated by the quad zygoma protocol using the Anatomy-Guided Approach (AGA).

A total of 56 patients who received 224 zygomatic implants manufactured by Nobel Biocare (n = 204), Straumann (n=16), and Southern Implant (n = 4) were included and followed for a period of 8.8 ± 3.9 years (range, 1.2-17.0).

Implant survival rate was 97.7%. All patients received immediate acrylic prostheses. The successful rates for the definitive prosthesis were 98.2%.

In 48 patients, the mean score of the OHIP-14 questionnaire was 1.7 ± 2.6 with a follow-up period of 9.0 ± 4.1 years. Local orofacial inflammation (35.7%) and sinusitis (12.5%) were the most common complications, occurring at a mean follow-up of 10.0 (range, 4.2-14.9) and 10.3 (range, 4.3-16.2) years, respectively.

The authors concluded, “The site preparation protocol of the N1 implant system, which includes the use of drilling tools at low speed with no irrigation, simplifies implant site preparation and seems to favor peri-implant bone healing.”

Read the full study in the open-access journal.

2. Clinical outcomes and biological and mechanical complications of immediate fixed prostheses supported by zygomatic implants: A retrospective analysis from a prospective clinical study with up to 11 years of follow-up.

Agliardi EL, Panigatti S, Romeo D, et al. Clin Implant Dent Relat Res. 2021;23(4):612-624.

In this retrospective study, Dr. Agliardi et al. focused on the clinical outcomes and the prevalence of surgical, biological, and prosthetic complications of implant-fixed complete dental prostheses supported by zygomatic implants. 34 patients who had received 90 zygomatic and 53 standard implants (all manufactured by Nobel Biocare) were followed up to 11 years. With only two conventional implant failures, the success rates for conventional and zygomatic implants were 96.2% and 100%, respectively.

No prosthesis was lost throughout the follow-up period. The main surgical complication was the perforations of the Schneiderian membrane in five patients, and seven sinus cavities. Soft tissue hypertrophy ranged between 1.8% and 30% for conventional implants and 1.1%-35% for zygomatic implants. Also, inflammation under the prosthesis ranged between 33% and 50%. For the mechanical complications, abutment loosening was recorded in two patients (5.8%) tooth debonding and fracture of the prosthesis happened in five patients (14.7%), and loosening of the prosthetic screws was reported in one patient (2.9%).

The authors concluded, “Immediate rehabilitation of the severely atrophic maxilla with zygomatic implants alone or in combination with standard implants could be considered a viable treatment modality. [also] Advanced surgical skills, proper learning curve, and adequate prosthetic protocols are necessary to achieve high implant survival rates and reduced prevalence of surgical, biological, and prosthetic complications.”

Check out the full manuscript in PubMed

3. Retrospective cohort assessment of survival and complications of zygomatic implants in atrophic maxillae.

Vrielinck L, Moreno-Rabie C, Coucke W, et al. Clin Oral Implants Res. 2023;34(2):148-156. 

The study aimed to assess the zygomatic implant survival rate and associated complications through a longitudinal retrospective cohort in the long term. A total of 1391 implants (940 zygomatic and 451 conventional, all manufactured by Nobel Biocare) were placed in 302 patients with atrophic maxilla and followed up to 22 years.

The implants had machined (n=159) or anodized (n=781) surfaces. The failure rate of anodized surface implants (TiUnite®) was only 7% in this long-term study, but 23% in the smooth surface implants. The overall survival rate of zygomatic implants was 89.9% after up to 22 years (mean 7.9 ± 4.9).

Sinusitis was the most reported biological complication (n = 138) occurring at a mean follow-up time-point of 4.5 years, whereas infraorbital nerve hypoesthesia occurred more frequently in the non-infectious biological category (n = 8, meantime: 0.3 years).

The most frequent mechanical complication was screw fracture (n = 29, meantime: 4 years). Sinusitis, standard implant loss, zygomatic/peri-zygomatic region infection, and oroantral communication were significantly associated with the loss of zygoma implants.

The authors concluded, “Zygomatic implants offered a high survival rate for the rehabilitation of severely atrophied maxilla. Most losses occurred within the first 5 years. The most frequently observed complication was sinusitis which tends to develop several years following implant placement.”

Check out the full manuscript in PubMed.