The human bone-oxidized titanium implant interface: A light microscopic, scanning electron microscopic, back-scatter scanning electron microscopic, and energy-dispersive x-ray study of clinically retrieved dental implants.

BACKGROUND: Surface modification of titanium implants by anodic oxidation may lead to enhanced bone integration. For instance, in vivo studies have demonstrated formation of more bone contacts in less time than for turned control implants. In addition, oxidized implants have shown a higher resistance to torque forces, indicating a strong interlock between bone and the oxide layer. However, the structure of the oxidized titanium-bone interface in high resolution is not known. PURPOSE: The aim of the study was to analyze the human bone-oxidized titanium interface at a high-resolution level. Of particular interest was the relationship between bone tissue and the pores of the surface oxide. MATERIALS AND METHODS: Twelve clinically retrieved implants with an oxidized surface (TiUnite, Nobel Biocare AB, Göteborg, Sweden) were used. Seven were regular dental implants and five were experimental mini-implants and had been subjected to immediate, early, or no loading. They were retrieved after 5 to 9 months of healing and were processed and analyzed using light microscopy, scanning electron microscopy (SEM) in normal and back-scatter (BS-SEM) modes, and energy-dispersive x-ray (EDX) analysis techniques. RESULTS: Bone formation was observed to occur from adjacent bone structures toward the implant surface, and it was evident that bone formation had occurred at the implant surface. SEM, BS-SEM, and EDX revealed that mineralized bone had grown into the pores of the surface oxide layer, including pores with small diameters (< 2 microm). CONCLUSIONS: The clinically retrieved oxidized implants showed evidence of bone growth into the pores of the surface oxide layer. The findings indicate the establishment of a strong interlock between the bone and the oxidized titanium implant, which is suggested to be beneficial for clinical performance.

Immediate occlusal loading of Brånemark System TiUnite implants placed predominantly in soft bone: 4-year results of a prospective clinical study.

BACKGROUND: Immediate occlusal implant loading has been documented as a viable treatment option for various indications. However, most of the available studies reported on the short-term outcome of this treatment modality. PURPOSE: The purpose of this prospective clinical study was to document, on a long-term basis, the outcome of immediate occlusally loaded Brånemark System Mk IV TiUnite (Nobel Biocare AB, Göteborg, Sweden) implants placed to support fixed reconstructions in various regions of the jaws. MATERIALS AND METHODS: Thirty-eight patients received a total of 51 fixed prosthetic reconstructions, all of which were connected on the day of implant insertion. Twenty restorations replaced single teeth, 30 were fixed partial dentures, and 1 was a full-arch fixed lower restoration. These prostheses were supported by 102 Brånemark System Mk IV TiUnite implants (38 maxillary and 64 mandibular), the majority of which were placed in posterior regions (88%) and mainly in soft bone (76%). Resonance frequency measurements and marginal periimplant soft tissue evaluations were conducted during the course of the study. Furthermore, radiographic examinations were performed at the time of prosthesis delivery and at the 1- and 6-month and 1-, 2-, 3-, and 4-year follow-up visits. This report summarizes the results after 4 years of loading. RESULTS: Three maxillary implants were removed, although stable, in one patient at the 8-week follow-up owing to postoperative infection in the adjacent guided bone regeneration area. No implants were lost further on. This resulted in a cumulative implant success rate of 97.1% after 4 years of prosthetic loading. The mean marginal bone remodeling after 4 years of function was 1.3 +/- SD 0.9 mm. At 4 years, absence of marginal plaque and bleeding on probing was reported for 87% and 69% of the sites, respectively, thereby remaining unchanged since the 1-year follow-up. On average, the interproximal soft tissue fill increased for both mesial and distal papillae from scores of 1.4 +/- 1.1 and 1.0 +/- 1.1, respectively, at the preoperative assessment to 2.0 +/- 0.8 and 1.7 +/- 0.8, respectively, at the 4-year assessment. CONCLUSION: The applied immediate loading protocol, in combination with a slightly tapered implant design and a modified implant surface texture, was shown to be a successful treatment alternative in regions exhibiting soft bone.

One-year prospective three-center study comparing the outcome of a "soft bone implant" (prototype Mk IV) and the standard Brånemark implant.

BACKGROUND: Oral implant treatment ad modum Brånemark has been used for decades in the rehabilitation of edentate and partially dentate patients. Posterior jaw regions frequently exhibit bone of poor texture, and it is often difficult to obtain primary stability. Thus, it may prove beneficial to deviate from the original protocol and to use implants with a modified design, for example, with a slightly tapered geometry. PURPOSE: The purpose of the investigation was to compare the early behavior of a modified (prototype Mk IV, Brånemark System, Nobel Biocare AB, Gothenburg, Sweden; test) implant with that of the standard Brånemark implant (control) in regions of mainly type 4 bone. MATERIALS AND METHODS: Three Swedish centers participated, and a total of 44 patients were treated with oral implants for 39 maxillas and 5 mandibles. The study focused on the most distal right and left implant sites (88 implants), which were randomized to receive either a test or a control implant. Various parameters were recorded, such as registered insertion torque (OsseoCare), Nobel Biocare AB), wobbling during insertion, primary and secondary stability (as measured with resonance frequency), and marginal bone loss. The implants were followed up for 1 year. RESULTS: The test implant more frequently required a higher insertion torque and showed a significantly higher primary stability than the control implant. This difference in stability leveled out over time, and test and control implants exhibited similar secondary stability at abutment operation and at the 1-year visit. Wobbling during insertion was rarely recorded for either of the implant designs. The 1-year cumulative success rate was 93.1% for test implants and 88.4% for control implants. CONCLUSIONS: The modified implant design resulted in an increased primary stability, which may be important when placing implants in jaw regions of type 4 bone. However, independent of the achieved primary stability, successful implants tended to approach similar secondary stability in the two designs tested.

Resonance frequency analysis of implants subjected to immediate or early functional occlusal loading. Successful vs. failing implants.

OBJECTIVES: The objective of this study was to analyze the development of implant stability by repeated resonance frequency analysis (RFA) measurements during 1 year in 23 patients treated according to an immediate/early-loading protocol. The objective was also to evaluate the possible differences between failing and successful implants. MATERIAL AND METHODS: Eighty-one Brånemark System implants were placed in 23 patients for immediate/early-occlusal loading in all jaw regions. Thirty of the implants were placed in extraction sockets and 62 were subjected to GBR procedures. Apart from clinical and radiographic examinations, the patients were followed with RFA at placement, prosthesis connection and after 1-3, 6 and 12 months. Statistical analyses were carried out to study the possible differences between implants that failed during the study period and implants that remained successful. RESULTS: Nine implants failed (11.2%) during the 1 year of loading. RFA showed a distinct different pattern between the implants that remained stable and the implants that were lost. The implants that failed during the course of the study showed a significantly lower stability already after 1 month. CONCLUSION: Within the limitations of this study, it is concluded that failing implants show a continuous decrease of stability until failure. Low RFA levels after 1 and 2 months seem to indicate an increased risk for future failure. This information may be used to avoid implant failure in the future by unloading implants with decreasing degree of stability with time as diagnosed with the RFA technique.