# Full-Arch Implant Rehabilitation > Full-arch implant rehabilitation for BDS Oral Surgery — All-on-4 Malo protocol, tilted implants, cross-arch splinting, cantilevers and overdenture options. - Canonical URL: https://prepelephant.com/topics/bds/oral-surgery/full-arch-implant-bds - Exam / course: BDS · Subject: Oral Surgery - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Full-Arch Implant Rehabilitation", PrepElephant, https://prepelephant.com/topics/bds/oral-surgery/full-arch-implant-bds ## Direct answer Four implants — two of them tilted — can carry a complete fixed arch because a rigid cross-arch splinted prosthesis distributes forces across the whole framework. This is the All-on-4 concept of Malo: two axial implants in the anterior maxilla or mandible and two posterior implants tilted 30 to 45 degrees, straddling the maxillary sinus anteriorly or the mandibular canal superiorly, which converts short posterior bone into long implant anchorage and spreads the support polygon to shorten cantilevers. Reported survival in longitudinal series commonly exceeds 95 percent at five to ten years. The alternative full-arch strategies are six to eight implants with conventional positioning, zygomatic implants in the extreme maxilla, and implant overdentures on two to four fixtures — the economical standard in Indian practice. ## What you must remember - **The geometry:** two axial anterior implants plus two distal fixtures tilted 30-45 degrees; tilting lengthens the available bone path, keeps implant apices clear of the sinus and canal, and spreads the anterior-posterior support distance so cantilevers stay short. - **Immediate function:** with high insertion torque in all fixtures, a screw-retained acrylic provisional bridge is fitted within days or on the table — cross-arch splinting plus passive fit is what makes immediate loading safe. - **Cantilever discipline:** distal extensions are kept short — commonly within about one premolar unit, accepting a first molar stop only when the AP spread is generous — because cantilever forces scale with length. - **Surgical specifics:** alveoloplasty is often required to create restorative space (commonly about 15 mm between the fixture platform and the opposing occlusal plane for a screw-retained hybrid); multi-unit abutments straighten the tilted implants' prosthetic access angles. - **Prosthetic architectures:** fixed hybrid (acrylic teeth on a milled titanium or cobalt frame — retrievable, hygiene-friendly), fixed zirconia, and overdenture on Locator or bar attachments — each trading cost, hygiene and repairability. - **Complications:** prosthetic screw loosening or fracture, acrylic tooth wear and fracture, peri-implantitis around any of four load-bearing fixtures (one failure can unhinge the plan), phonetic and hygiene adaptation difficulty, and cantilever overload. - **Evidence anchor:** longitudinal All-on-4 series report implant survival above 95 percent at 5-10 years, with no survival penalty for tilted versus straight implants — the sentence that answers the exam's evidence question. ## From failing dentition to fixed teeth A 56-year-old with generalized severe periodontitis holds a panoramic film of a terminally dentate maxilla: every tooth grade 2 mobile, furcation involvement throughout, and a knife-edge posterior ridge under a pneumatised sinus. The decision tree runs: save nothing, plan the transition. Extraction of all remaining maxillary teeth is combined with alveoloplasty to level the ridge and create restorative space. Two implants go axially into the lateral incisor region; the posterior implants are placed just in front of the sinus walls, tilted roughly 35-40 degrees so their length runs along the anterior sinus wall instead of into it — 4 mm of vertical bone thus receives a 15 mm fixture. Multi-unit abutments correct the angulations, and because insertion torque is high in all four, her existing denture is converted chairside into a screw-retained provisional the same week: no removable prosthesis at any point in her treatment. Mucosal healing and integration are checked over three to four months, hygiene around the fixed provisional is coached — super floss and water irrigators under the frame — and the definitive milled-frame hybrid is delivered against the mandibular dentition or opposing fixed arch. ## Where students slip The question examiners use to separate understanding from recall is why tilting helps: not "because it is easier to place" but because it recruits the dense anterior bone zone, avoids grafting the sinus or canal region, and widens the antero-posterior spread that mechanically supports the cantilever — force distribution is the point. The second slip is prosthetic amnesia: candidates describe the surgery fluently and then forget that everything rests on cross-arch splinting, passive fit, and retrievability, which is why one loose screw is a maintenance visit while one fractured hybrid frame is a laboratory event. The third is offering All-on-4 to everyone: the edentulous patient with good posterior bone is served by conventional placement, the extreme maxillary atrophy case belongs to zygomatic implants, and the patient who cannot afford a fixed hybrid is served better by a two-implant overdenture than by a compromised fixed compromise — in Indian practice the overdenture remains the most common full-arch implant solution precisely on cost-benefit grounds, and saying so earns viva credit. ## Frequently asked questions ### Why are the posterior implants tilted 30-45 degrees? Tilting uses long fixation paths along the anterior sinus wall or above the mandibular canal, avoiding grafting, and increases the antero-posterior spread supporting shorter cantilevers. ### What allows immediate loading of a full-arch prosthesis? High insertion torque in every fixture combined with a rigid, passively fitting, cross-arch splinted provisional that splints the implants into one biomechanical unit. ### How long can the distal cantilever be? Commonly kept within about one premolar-to-first-molar unit depending on the AP spread, since cantilever bending forces grow with length and implant number is fixed at four. ### What are the main prosthetic complications? Screw loosening or fracture, acrylic tooth and denture base wear or fracture, peri-implantitis of individual fixtures, and hygiene difficulty under the frame. ### What is the economical full-arch alternative? An implant overdenture on two to four implants with Locator or bar retention — fewer fixtures, simpler maintenance, and the most widely used full-arch solution in Indian practice.