All-on-X Full-Arch Implant Planning Calculator

Plan All-on-4, All-on-6, or All-on-8 full-arch rehabilitation cases. Enter bone dimensions, A-P spread, loading target, and prosthetic preferences to get cantilever safety analysis, bone adequacy checks, immediate loading eligibility, prosthetic material guidance, and a copyable clinical planning note. All calculations follow the Maló All-on-4 protocol and published EAO consensus guidelines.

⚠️ Clinical decision support only — CBCT analysis and specialist assessment are mandatory before surgery.

1. Case Setup

Maló 2003 · CIDR · original All-on-4 Maló 2011 · COIR · 7-yr follow-up
Testori 2021 · Clin Oral Implants Res · EAO immediate loading

2. Bone Assessment

Enter values from CBCT or OPG measurement.

Maló 2003 · min 10 mm

Symphysis (mandible) or nasal floor to crest (maxilla)

min 8 mm for tilted

Above inferior alveolar nerve (mandible)

min 5 mm

Narrowest point along planned implant sites

Lekholm & Zarb 1985
EAO 2021 · ≥35 Ncm for immediate

Lowest torque recorded across all implants

ISQ ≥65 for loading

Leave blank if RFA not performed

3. A-P Spread & Cantilever

A-P spread = distance from most anterior implant to a line connecting the two most distal implants. Measure from your surgical plan or CBCT.

Francetti 2008 · Clin Oral Implants Res Maló rule: ≤ 1.5× AP

Typical All-on-4 mandible: 18–22 mm

Distal extension beyond most distal implant

Typically 10 (All-on-4) to 14 (full arch)

Distal implant tilt to increase A-P spread & avoid anatomy

4. Patient Risk Factors

Chrcanovic 2016 · J Oral Rehabil · parafunctional loading meta-analysis
Chrcanovic 2015 · J Dent · OR 2.23 failure risk
Cawood & Howell 1988 · Int J Oral Maxillofac Surg

5. Prosthetic Material

Select intended definitive prosthesis material.

Configuration
All-on-4 · Mandible
Immediate loading · 2 axial + 2 tilted (45°)
Prosthetic teeth
12
Tilt angle
45°
A-P spread
20 mm
Material
—

Cantilever Safety Analysis

A-P Spread 20.0 mm
Max safe cantilever (1.5×) 30.0 mm
Adjusted for bruxism 30.0 mm
Planned cantilever 15.0 mm
030 mm (max)
Within safe limit

Bone Adequacy Checks

Immediate Loading
Overall Case Risk
Low

Prosthetic Recommendation

Schematic Arch Plan

Axial Tilted A-P spread Cantilever

Schematic only — not to patient scale

Clinical Planning Note


        


        
        

          Evidence basis: Maló et al. 2003/2011 All-on-4 protocol; Patzelt et al. 2014 systematic review; Testori & EAO 2021 immediate loading consensus; Chrcanovic 2015/2016 risk meta-analyses; Cawood & Howell 1988 atrophy classification; Lekholm & Zarb 1985 bone quality classification.
        


      

    

  


  
  

    
Frequently Asked Questions

    

      

        What is A-P spread and how does it determine cantilever length?
        

          A-P spread (anterior-posterior spread) is the distance from the most anterior implant to a line connecting the two most distal implants. The safe cantilever limit is 1.5× the A-P spread (Maló's rule). For a 20 mm A-P spread, the maximum cantilever is 30 mm. For bruxers or D4 bone, use a 1.0–1.2× multiplier to reduce biomechanical risk.
        

      

      

        What bone dimensions are needed for All-on-4?
        

          Minimum 10 mm anterior height (symphysis / nasal floor to crest), ≥5 mm ridge width. For tilted posterior implants: minimum 8 mm above the inferior alveolar nerve (mandible) or available for the tilted path (maxilla). Widths below 5 mm require ridge splitting or grafting.
        

      

      

        What insertion torque is required for immediate loading?
        

          The EAO 2021 guidelines and Maló protocol require a minimum insertion torque of 35 Ncm across all implants. ≥45 Ncm is preferred. If any implant is below 35 Ncm, switch to a delayed (8–12 week) loading protocol to prevent micromovement during osseointegration.
        

      

      

        All-on-4 vs All-on-6 — which is better?
        

          All-on-4 minimises grafting and surgery time — ideal for moderate atrophy. All-on-6 distributes occlusal load across more implants, allowing longer cantilevers and better tolerance of parafunctional loads. Patzelt et al. (2014) found comparable survival rates (97.3% All-on-4) across studies. All-on-6 is generally preferred for bruxers, larger arches, or zirconia restorations.
        

      

      

        When should zygomatic implants be considered?
        

          Zygomatic implants are indicated when posterior maxillary bone height is less than 4–5 mm with insufficient bone for tilted implants, and when the patient declines sinus grafting. They anchor into the zygoma and allow immediate loading. First described by Brånemark (1998) and validated in severely atrophic maxillae (Aparicio 2006).
        

      

      

        Which prosthetic material is best for All-on-4?
        

          Acrylic PMMA is used for immediate provisionals. Titanium-reinforced hybrid is the most common definitive choice — balances strength, weight, and repairability. Monolithic zirconia offers superior aesthetics but is not repairable and is contraindicated for uncontrolled bruxers due to high stress transfer. PFT frameworks are the gold standard but have the highest cost and lab complexity.