Clinical Implant Dentistry and Related Research

Little is known about the long‐term outcome of implants placed in the atrophic maxilla using osteotome sinus floor elevation (OSFE) without grafting.

The study aims to evaluate the long‐term efficiency of the procedure and stability of the peri‐implant bone formed following implant placement without grafting into resorbed posterior maxilla.

Twenty‐five implants (≤10 mm in length) were placed in 17 patients using OSFE without grafting. The mean residual bone height was 5.4 ± 2.3 mm. Bone levels were evaluated at 1, 3, 5, and 10 years using periapical radiographs.

Fifteen patients (23 implants) participated in the 10‐year examination. All implants fulfilled the survival criteria. Following surgery, the implant sites gained endo‐sinus bone (mean: 3.0 ± 1.4 mm). The mean crestal bone loss (CBL) was limited to 1.0 ± 0.9 mm. The difference in mean endo‐sinus bone gain and CBL was statistically significant between 1 and 10 years, but not between 3 and 5, 3 and 10, and 5 and 10 years.

At 10 years, the implant survival rate was 100%. Endo‐sinus bone was mainly gained during the first year. This study demonstrates the long‐term predictability of OSFE without grafting and simultaneous implant placement.

Based on three‐dimensional implant planning software for computed tomographic (CT) scan data, customized surgical templates and final dental prostheses could be designed to ensure high precision transfer of the implant treatment planning to the operative field and an immediate rigid splinting of the installed implants, respectively.

The aim of the present study was to (1) evaluate a concept including a treatment planning procedure based on CT scan images and a prefabricated fixed prosthetic reconstruction for immediate function in upper jaws using a flapless surgical technique and (2) validate the universality of this concept in a prospective multicenter clinical study.

Twenty‐seven consecutive patients with edentulous maxillae were included. Treatments were performed according to the Teeth‐in‐an‐Hour™ concept (Nobel Biocare AB, Göteborg, Sweden), which includes a CT scan‐derived customized surgical template for flapless surgery and a prefabricated prosthetic suprastructure.

All patients received their final prosthetic restoration immediately after implant placement, that is, both the surgery and the prosthesis insertion were completed within approximately 1 hour. In the 24 patients followed for 1 year, all prostheses and individual implants were recorded as stable.

The present prospective multicenter study indicates that the prefabrication, on the basis of models derived from three‐dimensional oral implant planning software, of both surgical templates for flapless surgery and dental pros‐theses for immediate loading is a very reliable treatment option. It is evident that the same approach could be used for staged surgery and in partial edentulism.

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.

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.

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.

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.

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.

Leukocyte‐platelet‐rich plasma (L‐PRP) is considered an important source of growth factors, especially Transforming growth factor β 1 (TGF‐β1), which modulates the proliferation and regulation of mesenchymal cells, and also exerts an influence on the hematopoiesis, osteogenesis, and adipogenesis in bone microenvironment. Thus, the aim of this study was to evaluate the effect of L‐PRP on the calvarial bone repair and compare its results on the presence of TGF‐β1, CD34, CD45, bone morphogenetic protein 2 (BMP2), BMPR1B, and Runx2 proteins detected by immunohistochemistry.

Four bone defects were created on the calvaria of 23 rabbits. The defects were treated with autograft, L‐PRP alone, and L‐PRP mixed with autograft. The animals were euthanized at 2, 4, and 6 weeks post‐surgery.

Unlike autograft and sham groups, the defects treated with L‐PRP demonstrated significant positivity to TGF‐β1, while the BMP2 was scarce. These results coincided with the lower bone matrix deposited and larger medullary area, which were composed of fibrosis, when treated with only L‐PRP, or intense adiposity on defects filled with L‐PRP mixed with autograft. The fibrosis that occurred was associated with a minor percentage of osteoproteins, intense presence of CD34⁺ CD45⁻ cells, and significant expression of TGF‐β1 in all time periods analyzed. The adiposity occurred from the major presence of osteoprogenitor BMPR1B ⁺ Runx2⁺ cells simultaneously to BMP2⁻ TGF‐β1⁺ and CD34⁺ CD45^+/− expressions predominantly on the earlier period.

From this study, it can be concluded that the L‐PRP used alone or mixed to autograft hindered the osteoneogenesis due to suppression of immunoexpression of BMP2, while the immunopositivity of TGF‐β1 was intense. When used alone, the L‐PRP induced a fibrotic condition associated with TGF‐β1 presence and lack of osteoproteins, but when L‐PRP was mixed to autograft, it induced the presence of the osteolineage cells (BMPR1B ⁺ Runx2⁺), but also inhibited the terminal osteoblastic maturation associated with the lack of BMP2 and the presence of TGF‐β1⁺, a fact that contributed to cellular transdifferentiation into fat cells.

The reasons for long‐term marginal bone loss around oral implants are not well understood.

The aim of this paper is to analyze presented evidence behind anticipated reasons for long‐term marginal bone loss around oral implants.

A computerized research was conducted onPubMed inApril 2011 with the following keywords: oral implants and marginal bone resorption/crestal bone loss/bone loss/bone resorption. This search resulted in a total of one thousand one hundred ninety‐four papers of which seven hundred fifty‐three were clinical contributions. Further search and filtering finally resulted in 21 experimental studies and one hundred sixteen clinical studies, which were reviewed.

No evidence was found that primary infection caused marginal bone resorption. Clinical papers that have reported high levels of peri‐implantitis were not supported by data given. Clinical evidence was presented that the so‐called combined factors (implant hardware, clinical handling, and patient characteristics) may lead to marginal bone resorption. However, once tissue damage has been caused by combined factors, inflammation and/or infection may develop secondarily and then result in peri‐implantitis that may need particular clinical treatment.

As marginal bone loss primarily depends on numerous background factors, it seems logical that, for example, the use of poorly constructed implants placed and handled by untrained clinicians may result in high numbers of patients with secondary problems in form of peri‐implantitis; having said this, control of combined factors may likewise lead to very good clinical results where peri‐implantitis would represent a very rare disease indeed even at follow‐up times of 10 years or more.

A 3‐year proof‐of‐principle study was initiated to evaluate the clinical efficacy of immediately loading titanium dental implants with surfaces enhanced with porous tantalum trabecular metal (PTTM). First‐year interim results are presented.

Healthy, partially edentulous patients (n = 30) were enrolled and treated per protocol (minimum insertion torque: ≥35 Ncm) with 37 implants placed in one or two premolar or molar locations in either jaw (study group). Implants were immediately provisionalized out of occlusion with single acrylic crowns. After 7 to 14 days of soft tissue healing, implants were definitively restored in occlusion with ceramometal crowns. Because most study group implants (54.1%, n = 20) had less than 1 year of clinical follow‐up, this interim analysis was limited to the first 22 consecutively placed implants in 17 subjects (10 women and 7 men) who completed 1 year of clinical follow‐up to date (focus group).

To date, one implant failed to integrate in the study group (survival = 97.3%, n = 36/37). Focus group implants achieved 100% (n = 22/22) survival with 0.43 ± 0.41 mm of mean marginal bone loss. There were no serious complications.

Early clinical findings indicated that immediate loading of PTTM implants was safe and effective under the controlled study conditions.