Rehabilitation of the Atrophic Maxillary Arch with Tilted Implants Protocol: A Proposed Classification of Various Situations

The majority of classifications for implant placement are based on the morphology of the available bone. The positions and angulations of implants in all forms of atrophy are not emphasized. Clinicians find it relatively difficult to insert the posterior tilted fixtures such that maximum anchorage of the bone can be obtained for enhanced primary stability, and there is unpredictability since the exit points (implant apex position) of these implants are not known and visualized prior to treatment. The purpose of this article is to classify the entry points, angulations, and exit points for 6 tilted maxillary implants in anterior-posterior distribution for prompt decision-making and ease of surgery as well as to capitalize on the available bone width.

The retrospective radiographic analysis was performed for 150 maxillary arch edentulous patients restored with fixed prosthesis supported by six tilted implants from April 2021 to April 2023. Post-operative Orthopantomograph (OPG) tracings were performed for maxillary sinus borders to classify the sinus pneumatization, and the entry and exit points of implants were noted with respect to the prosthetic teeth, basal anchoring bone, and implant angulations.

Of the arches treated, 63 were SP1, 34 were SP2, and 16 were SP3 in the maxilla. Many combination arches were encountered as well, including 32 cases of SP1 + SP2 and 5 of SP2 + SP3 combinations. The common preferred entry points were canine, second premolar, and second molar areas.

A functional surgical classification aids in placing all 6 tilted bicortical implants for immediate function while being versatile enough to be used in delayed cases as well. The knowledge of this classification helps to visualize the entry/fixation points, minimizing unpredictable and morbid grafting surgical procedures. It also aids in efficiently delivering patient-centric, minimally-invasive, predictably stable, biomechanically sound, and fixed implant treatments without cantilever in complete edentulism.