Revisions of failing maxillary traditional hybrid dental implant treatments by Dr. Simon Oh with the exceptional “zygomatic and pterygoid implants” by Noris Medical

Surgery by Dr. Simon Oh

Abstract

Revisions of failing maxillary traditional hybrid dental implant treatments can become complicated by the lack of available bone in the maxilla. Having the skill set to provide non-conventional implants such as zygomatic implants and pterygoid implants is paramount in the revision of maxillary hybrid dental implant therapy.

Case

This 50-year-old female with a past medical history of refractory depression and anxiety, presented with a chief complaint of soreness in the upper jaw. The patient had hybrid dental implant therapy 10 years prior, in another state. Upon examination, failing dental implants were noted, as well as unused dental implants with multiple thread exposures. The exposed implants displayed poor coverage of keratinized tissue, as well as multiple thread exposures. The patient had pain on palpation as well. The prosthesis was immobile. After consulting with the patient, it was decided to take the patient to surgery to remove all failing implants and place new dental implants. The patient expressed an absolute need for immediate loading, so a discussion about non-conventional implants took place and was agreed upon.

Surgical Course

This patient was intubated without complications. An attempt to access multiunit level screws was unsuccessful, dental composite had invaded the screw hex. At this time, it was decided to section the prosthesis, and remove the implants. After sectioning the prosthesis into three segments, the implants were easily removed. Upon removal, it was discovered that the prosthesis had no multiunit abutments, and had a combination of fixture level non-engaging abutments, along with some cement-retained abutments.
After the curettage of granulation tissues, two conventional Noris Medical Tuff dental implants were placed in the premaxilla in the area of the lateral incisors. These implants torqued at 30NCm. In light of the low torque in the premaxilla and the lack of residual maxillary bone, a decision was made to over-engineer the maxilla with parallel quad zygomatic implants in positions of the first premolar and canine locations bilaterally, thus provide enough composite torque to allow for immediate loading, while also providing adequate Antero-Posterior Spread.
After the four zygomatic implants were placed, torque on all implants was retested. Upon testing, a greenstick fracture had occurred (white arrow), extending from the buccal plate of the alveolus, into the nasal rim on the right lateral implant. This implant lost all torque and was then removed. The left lateral implant torqued at 25NCm at this time and was a poor candidate for immediate loading.
Upon re-evaluation of the condition of each implant, poor AP spread was noted, and so the decision to augment the case with pterygoid implants was made to fulfill proper AP spread. Bilateral Noris Medical Pteryfit pterygoid implants were placed, which brought the total arch composite torque value to over 250 NCM, along with excellent AP spread. It was decided to immediately load the four zygomatic implants, along with the two pterygoid implants, and to bury conventional anterior implant.
After the healing period, the lateral position implant will be uncovered and included in the final prosthesis to reduce any anterior cantilever.

Discussion

Revisions of failing traditional hybrid dental implant therapy can bring many complications and challenges. In this case, mid surgical corrections had to be made to rescue poor AP spread secondary to the greenstick fracture in the premaxilla after four parallel zygomatic implants were placed, via pterygoid implants. The use of Noris Medical zygomatic and pterygoid implants were paramount in the revision and reconstruction of this patient’s maxilla.

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