Crestal remodelling and osseointegration at surface-modified commercially pure titanium and titanium alloy implants in a canine model.

BACKGROUND: Ti-6Al-7Nb alloys exhibit enhanced mechanical properties and corrosion resistance and may represent an improvement to present commercially pure (CP) titanium oral implant technology. OBJECTIVES: To evaluate crestal remodelling and osseointegration at CP titanium compared with Ti-6Al-7Nb alloy oral implants using a canine model. METHODS: Two threaded anodized CP titanium and two Ti-6Al-7Nb alloy anodized oral implants (ø4.5 × 6.1 mm) were placed into each jaw quadrant in the edentulated posterior mandible in six adult male Hound Labrador mongrel dogs. Abutments were placed onto the implants, and the mucogingival flaps were adapted and sutured for transmucosal wound healing. Block biopsies were collected for histometric analysis following an 8-week healing interval. RESULTS: Healing was uneventful. Bone density outside and within the root of the threads averaged (± SE) 49.0 ± 4.5% and 38.7 ± 5.1% for CP titanium implants and 43.2 ± 3.6% and 34.2 ± 4.8% for Ti-6Al-7Nb alloy implants. Mean osseointegration reached 68.0 ± 4.4% and 62.8 ± 2.5% for CP titanium and Ti-6Al-7Nb alloy implants, respectively. Although crestal resorption at lingual sites averaged 0.2 ± 0.1 mm for both technologies, crestal resorption at buccal sites averaged 0.9 ± 0.2 and 1.0 ± 0.6 mm for CP titanium and Ti-6Al-7Nb alloy implants, respectively. There were no statistically significant differences between implant technologies for any parameter assessed. Notably, advanced/advancing buccal crestal resorption exposing the implant threads was observed in 50% of the implants (four of six animals) regardless of implant technology; osteoclastic resorption still observed at 8 weeks following implant placement. CONCLUSION: Within the limitations of study, anodized Ti-6Al-7Nb alloy implants may represent a feasible alternative to benchmark anodized CP titanium implants. Remodelling of the buccal crestal plate resulting in advanced bone loss appears a major impediment to oral implant osseointegration and possibly, in extension, implant maintenance.

Implant/Abutment Biomechanics and Material Selection for Predictable Results.

Change in crestal bone height and volume around endosseous dental implants is a complex issue involving interactions among many variables such as surgical approach, patient health, volume of hard and soft tissues, and implant configuration. Establishing and maintaining a soft-tissue seal around transmucosal abutments on bone-level implants or on the collar of one-stage tissue-level implants is paramount to maintaining crestal bone height, and failing to do so will result in apical migration of the soft tissue onto the implant. Bone-level implants have been constructed with many connection configurations. Locking-taper conical connection implants have proven superior to buttress joint implants at achieving a tight seal and eliminating the microgap at the implant-to-abutment junction and have demonstrated improvements in crestal bone maintenance. Attaining a transmucosal seal on locking-taper conical connection implants is dependent on the use of proven tissue-compatible materials such as titanium and zirconia. Gold and dental porcelain directly to the bone-level implant has been shown to cause tissue recession and bone loss around the implant; use of these materials directly to the implant interface should be confined to one-stage tissue-level implants. Lastly, proper abutment processing and clinical handling finalize the process. Poor dental laboratory processing can lead to loss of the tight locking-taper conical connection seal and screw loosening, while clinicians must keep the abutments clean and sterile. Best practice is for clinicians to inspect all abutments upon receipt from the lab and clean them with soap and water, followed by autoclave sterilization.

Use of Authentic, Integrated Dental Implant Components Vital to Predictability and Successful Long-Term Clinical Outcomes.

The accepted requirements for achieving long-term maintenance and performance of implant treatments include properly matched implant system components, a precise fit and connection between the abutment and implant, and appropriate preload. Satisfying these requisites can be predictably achieved when authentic and suitably compatible components that are engineered and marketed as an integrated implant system are placed. To the contrary, intermixing third-party or aftermarket implant components could result in unpredictable sequelae that negatively affect implant treatment outcomes. Because implant manufacturers strive to balance and integrate all aspects of implant system design (eg, abutment, implant, connections), dentists should understand how and why individual implant component characteristics (eg, fatigue strength, fracture resistance) affect the strength and integrity of the overall implant complex.