When a dental implant fails, the cause is rarely the surgeon's drilling technique. My research — including my most-cited publication in Quintessence International on marginal bone loss around implants, and my subsequent retrospective cohort study in Clinical Oral Investigations on implant-retained overdentures — consistently points to the same conclusion: the variables that most powerfully predict implant success are biological, systemic, and behavioural. At Taki Dent, we assess every patient against these variables before treatment begins.
Osseointegration: What It Actually Is
Osseointegration — the term coined by Per-Ingvar Brånemark in the 1960s — describes the direct structural and functional connection between living bone and the surface of a load-bearing implant, without any intervening fibrous tissue. For an implant to be clinically successful long-term, it must achieve two forms of stability:
Primary Stability
Mechanical engagement at the time of placement. Determined by bone density, implant design, and surgical technique. Assessed by insertion torque and resonance frequency analysis (ISQ values).
Secondary Stability
Biological bonding through new bone formation around the implant surface. Develops over 4–12 weeks and depends on surface chemistry, systemic health, and local biology.
The critical "stability dip" occurs 2–4 weeks post-placement when primary stability decreases as initial bone remodels, but before secondary stability has fully developed. This window is when early loading failures typically occur.
Bone Quality and Quantity
The Lekholm-Zarb bone quality classification remains the most clinically useful framework. Dense cortical bone (D1, D2) provides excellent primary stability and supports predictable osseointegration. Soft cancellous bone (D3, D4) — commonly found in the posterior maxilla — requires longer healing times, wider or longer implants where anatomy permits, and in many cases a modified loading protocol.
Bone volume is equally important. Minimum dimensions for reliable implant placement are approximately 1.5 mm of bone on each side of the implant and 1.0 mm apically. Below these thresholds, bone augmentation before or simultaneous with implant placement becomes necessary.
Implant Surface Technology
Modern implant surfaces are not neutral titanium. The major systems used at Taki Dent — Straumann SLA, Nobel Biocare TiUnite, Dentsply XP Coarse — have surface modifications specifically engineered to accelerate osteoblast attachment and proliferation. These processes include:
- Sand-blasting and acid etching (SLA): Creates a macro- and micro-rough surface topology that substantially increases the contact surface area for bone cells.
- Hydrophilised surfaces (SLActive): Chemically active titanium surface with superhydrophilicity. Reduces osseointegration time by approximately 30% in controlled studies.
- Anodised surfaces (TiUnite): Electrochemically oxidised titanium dioxide layer with an open tubular microstructure, enhancing osseoconduction.
The clinical implication of surface science is that implant brand selection genuinely matters. A budget, unvalidated implant system placed in poor bone with an inadequate surface will fail at higher rates than a CE-marked, clinically validated implant in the same bone. This is one reason I am transparent with patients about the implant systems I use.
Smoking: A Major Modifiable Risk Factor
Smoking remains one of the best-evidenced risk factors for implant failure. Nicotine is vasoconstrictive — it reduces blood flow to the alveolar bone and soft tissues, impairing the delivery of osteogenic cells and growth factors needed for osseointegration. Systematic reviews consistently report failure rates 2–3 times higher in smokers than non-smokers.
My protocol requires patients to stop smoking a minimum of four weeks before implant surgery and maintain abstinence through the healing period. I do not classify this as an optional recommendation — it is a clinical requirement for predictable outcomes. The risk can be partially mitigated by enhanced surface implants and longer healing protocols, but cannot be eliminated while smoking continues.
Diabetes and Systemic Health
Controlled Type 2 diabetes (HbA1c below 7.5–8.0%) is not a contraindication to implant treatment. However, uncontrolled diabetes substantially impairs wound healing and bone metabolism through several mechanisms: elevated blood glucose disrupts collagen synthesis, impairs neutrophil function, and promotes pro-inflammatory cytokines that increase marginal bone loss.
For diabetic patients, I require a recent HbA1c result before surgery. If this is above 8.5%, I defer treatment until glycaemic control improves in collaboration with the patient's physician. Post-operatively, more frequent review appointments — at 3, 6, and 12 months — are essential to detect early peri-implant inflammation before it progresses to bone loss.
Post-Operative Protocols and Maintenance
Long-term implant success requires structured maintenance. Peri-implantitis — the inflammatory destruction of bone around an implant — shares a similar aetiology with periodontitis and is equally influenced by patient oral hygiene. My maintenance protocol after definitive restoration is:
The evidence for maintenance is unambiguous: supported implant patients show significantly lower rates of peri-implant bone loss than unsupported patients. An implant is a long-term investment, and the aftercare programme determines whether that investment lasts 20+ years or requires revision at 7.