What Are All-on-4 Implants?

All-on-4 is a revolutionary dental implant technique that replaces an entire arch of teeth using just four strategically placed implants. Developed by Dr. Paulo Malo in the 1990s, this treatment provides a fixed, permanent solution for patients missing all or most teeth in an arch, offering immediate function and aesthetics while avoiding extensive bone grafting in most cases.

How All-on-4 Works

The Concept

Rather than replacing each tooth individually (requiring 10-14 implants per arch), All-on-4 uses four implants as anchor points for a full fixed bridge. Two implants are placed vertically in the front jaw where bone is typically denser, and two are angled 30-45 degrees in the back to maximize bone contact and avoid anatomical structures.

Why Angled Implants?

The angled posterior implants are the key innovation that makes All-on-4 possible:

• Maximizes bone contact: Longer implant path through available bone despite limited vertical height
• Avoids sinuses: Upper jaw angles away from maxillary sinuses, eliminating need for sinus lifts
• Avoids nerves: Lower jaw angles away from inferior alveolar nerve
• Distributes forces: Creates wider support polygon, improving load distribution
• Increases stability: Angled implants provide better resistance to lateral forces

The All-on-4 Procedure

Pre-Treatment Planning

Success depends on thorough planning:

• 3D CT scan: Essential for measuring bone, locating nerves/sinuses, planning implant positions
• Digital treatment planning: Computer software maps ideal implant locations
• Surgical guide fabrication: Custom 3D-printed guide ensures planned positions achieved
• Pre-fabricated prosthesis: Temporary teeth made before surgery for immediate placement

Surgery Day (2-3 hours per arch)

Recovery Timeline

• Day 1-7: Swelling and discomfort peak. Soft diet only. Pain managed with prescriptions.
• Week 2-4: Swelling subsides. Transition to softer foods. Most patients return to work week 2.
• Month 2-4: Osseointegration progressing. Gradual diet expansion. Follow-up checks.
• Month 4-6: Osseointegration complete. Final impressions for permanent bridge.
• Month 6+: Permanent bridge placed. Fully functional with normal diet.

Advantages of All-on-4

Fewer Implants Required

Often Avoids Bone Grafting

The angled implant technique utilizes available bone optimally, eliminating need for sinus lifts or major grafting in 70-80% of cases. This saves £3,000-£8,000 in grafting costs and 6-12 months of healing time.

Immediate Teeth

Most All-on-4 patients receive fixed temporary teeth on surgery day. No period without teeth, no uncomfortable dentures during healing. Resume eating soft foods within days.

Fixed, Non-Removable Solution

Unlike dentures, All-on-4 teeth don't move, don't require adhesives, and feel like natural teeth. Brush and floss normally (with adaptations). No embarrassing slipping or clicking.

Restores Chewing Function

All-on-4 restores 80-90% of natural chewing force, compared to 20-25% for dentures. Most patients can eat anything after final bridge placed, including tough meats, raw vegetables, and crunchy foods.

Prevents Further Bone Loss

Implants stimulate bone like natural tooth roots, halting the progressive bone loss that occurs with dentures. This preserves facial structure and prevents the "sunken face" appearance of long-term denture wearers.

Disadvantages and Limitations

Higher Upfront Cost

Requires Adequate Bone

While All-on-4 works with less bone than individual implants, you still need minimum bone volume. Extreme bone loss may require zygomatic implants or extensive grafting instead.

Not Reversible

All-on-4 requires removing any remaining teeth in the arch. This is permanent—you cannot go back to natural teeth. Thoroughly consider this commitment before proceeding.

Prosthesis Eventually Needs Replacement

While implants can last 20-25+ years, the prosthetic bridge typically needs replacement after 10-15 years due to wear. Replacement bridge costs £3,000-£6,000 but doesn't require new implant surgery.

All Implants Must Succeed

With only four implants supporting the arch, each is critical. Loss of one implant can compromise the entire restoration, though this is rare with proper patient selection and maintenance.

All-on-4 vs All-on-6

All-on-6 uses six implants instead of four, providing additional security and stability.

Who Is a Good Candidate?

Ideal Candidates

• Missing all or most teeth in one or both arches
• Currently wearing dentures and frustrated with instability
• Failing teeth requiring extraction
• Sufficient bone volume (at least 5mm height, 5mm width)
• Good general health and oral hygiene
• Non-smoker or willing to quit for treatment
• Realistic expectations about outcomes

Poor Candidates

• Active gum disease (must be treated first)
• Severe bruxism (teeth grinding) without willingness to wear nightguard
• Uncontrolled diabetes (HbA1c over 8%)
• Heavy smokers unwilling to quit (doubles failure risk)
• Insufficient bone and unwilling to consider alternatives
• Unrealistic expectations or psychological issues

Cost Breakdown

Success Rates and Longevity

Factors Affecting Success

• Smoking: Reduces success rate 10-15 percentage points
• Oral hygiene: Critical for long-term success
• Bone quality: Denser bone = better outcomes
• Surgeon experience: Learning curve exists; experience matters
• Regular maintenance: Professional cleanings every 4-6 months essential

Making Your Decision