Comparison of Intrasinus and Extrasinus Approach for the Placement of Zygomatic Implants in Severely Resorbed Edentulous Maxillary Arch Using Zygomatic Success Code - An In-Vivo Study

When extra-sinus and intra-sinus placed implants are tested individually, slight mobility should be detected with no other associated pathological signs. Instrument used for checking the implant stability is periotest.

Mobility of the implant comes from the elastic modulus of the anchoring zygomatic bone when they are bent by a remotely applied force. On the other hand, the movement must not be rotational, and it will disappear when implants are splinted together. A rotational movement should be considered as a sign of implant failure. Grade I- no mobility, no pain Grade II-light clinical mobility, no pain Grade III-clear clinical mobility, no pain (no evidence of disintegration of the apical part of the implant or rotation Grade IV- clear clinical mobility, rotation and pain evidence of disintegration of apical part of the implant)

Frequently associated complications such as rhinitis and sinusitis were assessed by two scoring systems: Lund-Mackay staging and the Lanza and Kennedy score.

Lund-Mackay stating and Lanza and Kennedy score

This system scored six sinus regions: anterior ethmoid, posterior ethmoid, maxillary sinus, frontal sinus, sphenoid sinus, and osteomeatal complex for sinus pathology. The score 0 represented no abnormality; 1 represented partial opacification; and 2 represented total opacification. For the osteomeatal complex, the score was either 0 or 2. This scoring was done for pre-operative and post-operative evaluation.

Lanza-Kennedy - Rhinosinusal Clinical Symptoms

It is patient-related questionnaire to identify the rhinosinusal clinical symptoms. Each symptom

question is answered by "yes" or "no". The diagnosis of sinusitis requires a "yes" answer in two or more major criteria, one major and two or more minor criteria, or purulence on nasal examination

Soft tissue around the zygomatic implant was assessed at 3 and 6 months after implant placement and prosthetic replacement, where the exposed implant surface was measured from the implant head to the soft tissue recession area.

Prosthetic success depends on the anatomic measurements to assess the implant position of the head of the zygomatic implant.

Four anatomical measurements will be performed to assess the following:

• Perpendicular distance between the tangent to the floor of the nose and sinus floor at the entrance of the zygomatic implant level.
• Perpendicular distance between the tangent to the floor of the nose and the crest of the alveolar ridge at the entrance of the zygoma implant level.

i. The height of the alveolar ridge at the location of the head of the zygomatic implant (measurement 2 minus 1)

• Distance between the midline of the palate and the center of the zygomatic implant head.
• Distance between the midline of the palate and the center of the alveolar ridge.

ii. The position of the head of the zygomatic implants with regard to the center of the crest of the alveolar ridge in the horizontal axial dimension (measurement 4 minus 3).

A positive value on this implant head position