AbstractStatement of problem.
The V-4 implant placement technique is important for restoring patients with maxillary atrophy, but little has been documented on the outcomes of these treatments.Purpose.
The purpose of this study was to evaluate the outcome of immediate function after 1 year when implants were placed without vertical bone augmentation in Cawood-Howell Classes IV-VI maxillary atrophy (Class C-D by the “all-on-four” site classification) with the nasal crest, lateral pyriform rim, and sometimes the zygoma for apical implant fixation.Material and methods.
Function of implants that had been immediately loaded were studied retrospectively after 1 year in 44 patients from 2 different clinics. For each patient studied, 2 angled implants were placed in the midline in the nasal crest/vomer area, and typically, 2 implants were engaged apically in the lateral pyriform rim bilaterally. All 4 of the implants used were angled toward the midline in a V formation, termed “V-4” implant placement. Insertion torque, anterior-posterior spread, implant diameter, implant length, and posterior cantilever were recorded. Implant survival and bone stability were assessed after 1 year. When the lateral pyriform was highly deficient (Class D), zygomatic implants were used posteriorly.Results.
A total of 179 implants were placed in 44 patients followed for 1 to 3 years. Six implants were lost, all in 1 patient. Anterior-posterior spread averaged 16 mm, with an average cantilever of 7.5 mm. Except for the lost implant sites, bone levels were stable throughout treatment for all patients.Conclusions.
The use of 4 implants angled toward the midline, including 2 implants placed into a V-shaped point at the nasal crest and 2 implants placed into an M-shaped point at the pyriform rim bilaterally, showed good stability after 1 year despite gross absence of bone mass as a result of severe maxillary atrophy. The V-4 placement pattern is important for patients with deficient bone mass between the sinus and nasal cavities. In Class D situations where lateral nasal rim bone mass is nearly absent, zygomatic implants can be used.