Biomedical subjects

Massimiliano Martignoni

Publications and source records attributed to Massimiliano Martignoni.

4 recordsLinked to original sources

PubMed2005

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.

Coated Materials, Biocompatible↗

PubMed2003

Immediate loading in the maxilla using flapless surgery, implants placed in predetermined positions, and prefabricated provisional restorations: a retrospective 3-year clinical study.

BACKGROUND: Immediate loading of dental implants shortens the treatment time and makes it possible to give the patient an esthetic appearance during the whole treatment period. PURPOSE: The aim of the present study was to evaluate an immediate-loading treatment protocol, which included flapless surgery, implants placed in predetermined positions and connected to prefabricated provisional restorations, and the 3-year clinical results. MATERIALS AND METHODS: A total of 97 Brånemark System Mk IV implants (Nobel Biocare AB, Gothenburg, Sweden) with a machined surface were inserted in the maxillas of 46 patients. A presurgical three-dimensional model of the patients' soft tissue and underlying alveolar bone anatomy was created, which allowed the clinician to place the implants in predetermined positions and connect them to prefabricated provisional restorations. A surgical template with drilling guides corresponding to each implant was used. The apical part of the master guide was equipped with a circular "mucotome," which punched out a 5 mm hole in the mucosa to eliminate the need for flap elevation. The patients received 25 fixed partial prostheses and 27 single-tooth restorations. Bone quality and quantity were assessed. Radiographic examinations were performed on the day of surgery/loading and at the 1-, 2-, and 3-year follow-up visits. RESULTS: All implant sites showed intact buccal and lingual bone walls during surgery, confirming the accuracy of the bone-mapping procedure. The prefabricated temporary restorations fitted, meaning that the implants were positioned clinically in the same way as on the cast. Nine implants in eight patients failed during the first 8 weeks of loading. This resulted in a cumulative survival rate of 91% after 3 years of prosthetic load. The survival rate of splinted implants was 94%. The number of failed implants was significantly higher in cases of single-tooth replacements and placement in soft bone sites and smokers. The failed implants were successfully replaced according to a two-stage protocol. All patients finally received the expected restoration. The marginal bone resorption was on average 1.0 mm during the first year of loading, 0.4 mm during the second year, and 0.1 mm during the third year. CONCLUSIONS: The study confirmed the feasibility of an immediate-loading treatment protocol in the maxilla, which included flapless surgery, implants and abutments placed in predetermined positions, and prefabricated provisional restorations. All failures occurred within the first 2 months of loading. The unchanged survival rate and the low average bone loss found during the following 34-month study period indicate a good long-term prognosis for the performed immediate-loading treatment.

Adult↗

PubMed2003

Immediate loading of Brånemark System TiUnite and machined-surface implants in the posterior mandible: a randomized open-ended clinical trial.

BACKGROUND: Immediate loading of osseointegrating implants shortens the treatment time and makes it possible to give the patient an esthetic appearance during the whole treatment period. A previous retrospective clinical study showed a success rate of 94.2% after 1 year of immediate loading of fixed partial constructions in the maxilla supported by machined-surface implants. The recently introduced Brånemark System TiUnite (Nobel Biocare AB, Gothenburg, Sweden) surface has been shown to better maintain primary implant stability and to help achieve secondary stability earlier compared with the machined surface. PURPOSE: The aim of the present study was to compare TiUnite and machined-surfaced Brånemark System implants when applying immediate loading of partial fixed bridges in the posterior mandible. MATERIALS AND METHODS: Forty-four patients were randomized for test and control therapy. In the test group, 22 patients received 66 Brånemark System TiUnite surface implants supporting 24 fixed partial bridges, all of which were connected on the day of implant insertion. In the control group, 22 patients received 55 Brånemark System machined-surface implants supporting 22 fixed partial bridges, which also were connected on the day of implant insertion. All constructions were two- to four-unit bridges. Bone quality and quantity were assessed. Radiographic examinations were performed on the day of surgery/loading and at the 1-year follow-up visit. RESULTS: Three TiUnite and eight machined-surface implants failed during the first 7 weeks of loading. This resulted in a cumulative success rate of 95.5% for TiUnite surface implants after 1 year of prosthetic load in the posterior mandible. The corresponding cumulative success rate for machined-surface implants was 85.5%. When using the machined-surface implants, the number of failed implants was significantly higher in smokers and in bone quality 4 sites. Such findings were not seen with the use of TiUnite implants, despite the fact that there were more smokers and more implants placed in bone quality 4 in this group. The marginal bone resorption after 1 year of loading was on average 0.9 mm (SD 0.7 mm) with the TiUnite implants and 1.0 mm (SD 0.9 mm) with the machined implants. CONCLUSIONS: The present study demonstrated a 10% higher success rate following immediate loading of partial fixed bridges in the posterior mandible supported by TiUnite surface implants compared with success with machined implants. When using the machined implants, the number of failed implants was significantly higher in smokers and in bone quality 4 sites. Such findings were not seen following the use of TiUnite implants.

Adult↗

PubMed2003

Histology of retrieved immediately and early loaded oxidized implants: light microscopic observations after 5 to 9 months of loading in the posterior mandible.

BACKGROUND: An increased number of publications report that one-stage surgery and immediate/early loading of dental implants may be a feasible approach for prosthetic reconstruction of the edentate patient. However, little is known about the histologic response to implants subjected to immediate/early loading in patients. PURPOSE: The aim of the present study was to histologically evaluate oxidized titanium implants subjected to loading immediately following surgery or after 2 months of healing and removed after 5 to 9 months loading. MATERIALS AND METHODS: Five patients participated in the study; each had consulted for implant treatment in the posterior mandible and subsequently volunteered to have extra implants inserted for the purpose of histologic research. Nine oxidized titanium implants (Brånemark System TiUnite , Nobel Biocare AB, Gothenburg, Sweden) were retrieved after 5 to 9 months in function. Two implants had been loaded the same day, whereas seven implants were loaded after 2 months of healing. Resonance frequency analysis was performed at retrieval on seven implants. Ground sections were prepared for histology and analyzed using light microscopic morphometry. RESULTS: Seven and 8.5 mm implants were placed, predominantly in quality 3 and 4 bone. Four implants were straight (Mk III), and five were tapered (Mk IV). All implants were clinically stable at retrieval and showed ISQ values of 65 to 79 with a mean of 71.4 +/- 4.4. Eight of the implants were able to be used for histology. A gross histologic examination showed an undisturbed healing of soft and bone tissues with no apparent differences between response to immediately and early loaded implants. Lamellar bone surrounded the implants, and remodeling was evident and more marked near the implant surface. A condensation of bone toward the implant surface was seen; this resulted in a lamina dura-like structure in trabecular bone. Thin rims of newly formed bone were often seen following the contour of the implant surface. The morphometric measurements showed a mean bone-to-implant contact value of 84.2 +/- 10.5% and a mean bone area value of 79.1 +/- 6.8%. The two immediately loaded implants showed bone-to-implant contact and bone area values of 92.9 +/- 0.1% and 84.9 +/- 0.9%, respectively. The corresponding values for the six early loaded implants were 81.4 +/- 10.6% and 77.1 +/- 6.8%, respectively. CONCLUSIONS: The present study demonstrated that oxidized implants subjected to immediate or early loading do integrate with soft and bone tissues in the posterior mandible.

Adult↗