Academy

Complex oral rehabilitation on zygomatic and lateral nasal implant

clinical case
Performed by Dr. Shveys Mirela, OMFS, DMD, MD
Malpositioned dental implants represent a challenge for every prosthodontist.
Although nowadays the market offers different systems that can correct the most difficult angulations, there are cases in which this is impossible, and the only solution is to remove them.
Dental implants can be malpositioned as a consequence of poor treatment planning, inaccurate surgery, inexperienced surgeons, or uncooperant patients.
Malpositioned implants may cause biomechanical problems due to the wrong occlusal forces, unacceptable esthetic appearance, or poor hygiene, and therefore, they must be extracted.
In some cases, removal of an osseointegrated important can lead to large soft and hard tissue defects, and the decision to extract using an implant retriever and counter-torque is the best technique for the maxilla. The use of burs or trephine might be necessary for the mandible, where the cortical bone around the implant makes this procedure more difficult.

A 68-year-old female was referred to our clinic for oral rehabilitation of her upper and lower jaws.
The patient had inserted 8 maxillary implants 1 year before, and an attempt of rehabilitation with a removable prosthetic on ball attachment on 2 of them. The others were considered to be ‘difficult‘ to correct (Fig 1)

Clinical examination revealed 6 of the implants exposed to the oral cavity, 3 of them too buccal, the other 3 palatal angulated, and 2 implants submerged. Posterior teeth were extruded in contact with the lower gingiva, making it difficult to have a correct occlusion. Lower teeth with chronic periodontitis, untreated (Fig 2, Fig 3)

On x-ray, we can see the huge vertical bone defect on the frontal maxilla (Fig  4)

The CBCT revealed bone loss on the frontal maxilla and around the implants, the malpositioned implant with vestibular angulation on the right, and palatal angulation on the left (Figs. 5 and 6).

 

The prediction on CBCT for zygomatic implants showed the extraspinal trajectory and the 90-degree angle between the maxilla and zygomatic bone (Fig. 7), a situation very difficult for the implant and soft tissue support.

The treatment plan included extraction of the implant’s maxillary and mandibular teeth and insertion of 4 zygomatic implants for the posterior and 2 classical implants anterior. The anterior maxilla was 4 mm high, and the solution proposed was to insert an angulated implant into the lateral nasal wall for cortical support.

During surgery, the implants and teeth were removed with minimal bone loss (Fig 8 . Fig 9),

and the insertion channels for zygomatic implants were prepared with diamond drills no 1 and 2 from the zygomatic set. The implants were inserted as planned (fig 10, fig 11, fig 12).

 

My protocol included the bone graft and buccal tissue flap for vestibular tissue support (Fig 13); as we know, gingival recession is one of the most frequent complications of zygomatic implants.

In contrast, 5 implants were inserted for fixed rehabilitation. (Fig 14, Fig 15)

The CBCT shows the implant position with bone support intrazygomatic and nasal wall (Fig 16, Fig 17, Fig 18, Fig 19)

The patient has fixed screwed prosthetics on both jaws, with good esthetics and functions.

2 year follow-up shows stability of the bone and soft tissue, as well as good masticatory function (Fig 20-22)

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