A 90-Year-Old’s Full-Arch All-on-4 Rehabilitation: Overcoming Severe Osteoporosis

This clinical case study documents a notable case in implant dentistry: the successful full-arch All-on-4 rehabilitation of an 89-year-old patient, whose final fixed restoration was completed as she turned 90. Operating on patients of such advanced age presents significant systemic and biomechanical challenges, which often leads clinicians to consider alternative prosthetic options.

This study outlines how the clinical team at Chengdu Anyu Dental Implant Hospital, led by CTO Professor Wu Dayi, managed severe osteoporosis and advanced age factors to achieve a successful outcome. This case was presented at the 2025 CDIC Implant Symposium and is now shared for international reference on cdchinadental.com.

This case represents the oldest patient to undergo an All-on-4 procedure at Anyu Dental Implant Hospital in recent years:

• Patient Background: Female, born in 1936.
• Clinical Timeline: All-on-4 surgical procedure performed in 2025 at age 89; final fixed bridge installed in 2026 upon reaching age 90.
• Initial Oral Condition: Near-complete edentulism. The upper jaw retained only two severely compromised teeth; the lower jaw retained only two teeth and three residual roots.
• Diagnostic Findings (CBCT): Pre-operative CBCT scans revealed pronounced osteoporosis. Qualitative grayscale assessment indicated low-density cancellous bone; specific Hounsfield Unit (HU) values were not available from the archived imaging data, presenting a primary technical challenge for primary implant stability.

In geriatric implantology, treating patients aged 80 and above elevates the procedure from local functional reconstruction to systemic vital-sign management. The core risks extend beyond localized bone integration:

1. Perioperative Systemic Complications: Surgical and anesthetic stress can trigger acute hypertensive crises, myocardial ischemia, or cerebrovascular accidents.
2. High Risk of Osseointegration Failure: Severe osteoporosis and decreased osteoblast activity significantly slow bone metabolism and integration. Unlike younger patients, bone healing in the elderly is non-linear and may require extended loading intervals.
3. Impaired Healing and Infection Risk: Age-related immune senescence slows soft-tissue wound healing. Peri-implantitis in elderly patients can progress rapidly and is difficult to reverse.
4. Metabolic Disruption: Prolonged fasting and surgical fluid management during extended procedures can induce hypoglycemia or electrolyte imbalances, potentially precipitating cardiac arrhythmias.

Mitigating these risks requires a structured Multidisciplinary Team (MDT) featuring experienced anesthesiologists and cardiologists.

Professor Wu Dayi tailored the surgical execution to overcome the patient’s compromised bone structure:

• Pre-operative Phase: Minimally invasive extraction of the remaining compromised teeth and residual roots in both jaws.
• Intra-operative Execution (Freehand Technique): Four CDIC implants were placed in the mandible using a freehand technique without a surgical guide. Bypassing the guide avoided localized heat accumulation during drilling and prevented cumulative spatial errors in soft cancellous bone, a rationale consistent with reports suggesting that guide-induced errors may be amplified in low-density bone. Professor Wu relied on over 40 years of proprioceptive feedback and tactile experience to navigate anatomical landmarks accurately.
• Abutment Selection: Following minor alveolar contouring, zero-degree composite abutments with gingival heights of 2.5 mm and 3.5 mm were selected based on clinical judgment of soft-tissue thickness and contour, refined over decades of experience, rather than by probe measurement alone.
• Primary Stability: Despite the soft cancellous bone, controlled under-drilling achieved an insertion torque of 35 Ncm—a milestone requiring extensive clinical judgment to distinguish genuine bone engagement from a false stop caused by debris or soft tissue—which, while below the ideal range for dense bone, is considered sufficient for immediate loading in compromised bone when coupled with a protective occlusal scheme.
• Post-operative Immediate Loading: Following flap closure, impressions were taken, and a custom fixed provisional bridge was delivered during the same appointment. The total in-clinic session—including surgery, laboratory steps, and prosthetic delivery—spanned seven hours (10:00 AM to 5:00 PM).

This successful outcome highlights the strict operational preconditions required at our institution for ultra-high-age implantology:

1. Dedicated Anesthesia Team: Continuous arterial line pressure, central venous pressure, and end-tidal CO₂ monitoring throughout the surgical session.
2. Emergency Infrastructure: Fully equipped surgical suites with defibrillators, ventilators, and an established transfer pathway to a tertiary hospital ICU.
3. Pre-operative MDT Clearance: Mandatory evaluations by cardiology, endocrinology, and anesthesiology, including echocardiograms, carotid ultrasounds, and coagulation profiles.
4. Sterile Operating Environment: ISO Class 5 (Class 100) or ISO Class 7 (Class 10,000) laminar airflow suites, depending on the procedure zone, to minimize post-operative infection risks.
5. Advanced Imaging: High-resolution CBCT to analyze bone density parameters and map the inferior alveolar nerve canal.
6. Perioperative Care for Extended Surgery: Extended operative time was managed with controlled fluid therapy, warming blankets, and intermittent lower extremity compression to prevent thromboembolism and hypothermia.
7. Post-operative Care Protocol: High-frequency, structured follow-up visits to monitor both oral healing and general systemic health.
   

Ethical Statement & Disclosures: Written informed consent was obtained from the patient prior to surgery. As a single-case report, these findings reflect the outcome of a highly experienced surgical team and may not be generalizable to routine clinical practice. Long-term follow-up data (≥12 months) will be reported in a subsequent publication.