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The structural and functional fusion of the surface of the dental implant with the surrounding bone (osseointegration) is crucial for the short and long term outcome of the device. In recent years, the enhancement of bone formation at the bone-implant interface has been achieved through the modulation of osteoblasts adhesion and spreading, induced by structural modifications of the implant surface, particularly at the nanoscale level. In this context, traditional chemical and physical processes find new applications to achieve the best dental implant technology. This review provides an overview of the most common manufacture techniques and the related cells-surface interactions and modulation. A Medline and a hand search were conducted to identify studies concerning nanostructuration of implant surface and their related biological interaction. In this paper, we stressed the importance of the modifications on dental implant surfaces at the nanometric level. Nowadays, there is still little evidence of the long-term benefits of nanofeatures, as the promising results achieved in vitro and in animals have still to be confirmed in humans. However, the increasing interest in nanotechnology is undoubted and more research is going to be published in the coming years.

Implant site preparation through drilling procedures may cause bone thermonecrosis. The aim of this in vitro study was to evaluate, using a thermal probe, overheating at implant sites during osteotomies through 2 different drilling methods (continuous drilling technique versus intermittent drilling technique) using irrigation at different temperatures. Five implant sites 13 mm in length were performed on 16 blocks (fresh bovine ribs), for a total of 80 implant sites. The PT-100 thermal probe was positioned 5 mm from each site. Two physiological refrigerant solutions were used: one at 23.78°C and one at 6.08°C. Four experimental groups were considered: group A (continuous drilling with physiological solution at 23.78°C), group B (intermittent drilling with physiological solution at 23.78°C), group C (continuous drilling with physiological solution at 6.08°C), and group D (intermittent drilling with physiological solution at 6.08C). The Wilcoxon rank-sum test (2-tailed) was used to compare groups. While there was no difference between group A and group B (W = 86; P =.45), statistically significant differences were observed between experimental groups A and C (W=0; P=.0001), B and D (W=45; P=.0005), and C and D (W =41; P=.003). Implant site preparation did not affect the overheating of the bone. Statistically significant differences were found with the refrigerant solutions. Using both irrigating solutions, bone temperature did not exceed 478°C. [ABSTRACT FROM AUTHOR]

Background: The aim of this retrospective study is to investigate the medium- to long-term prognosis of short implants in partially and totally edentulous patients with mandibular bone atrophy. Methods: The study involved 109 patients with 280 implants placed in the mandible. The implants were 7 or 8.5 mm long and 3.75 or 4 mm in diameter. The implant surfaces were machined (M; n = 176) or rough (R; n = 104). Patients were asked to attend a radiographic and clinical follow-up, and their previous clinical records and radiographs were assessed. Implant-related and prosthetic failures and complications were recorded. Results: The mean follow-up was 9 years (range of 5 to 16 years). The survival rate (SSR) and success rate (SR) were calculated using life-table analysis for both M and R short implants. The M implants had a 16-year SSR of 95.7% and a corresponding SR of 93.9%, whereas the 16-year SSR and SR for the R implants were 97.2% and 95.2%, respectively. The mean ± SD bone resorption for all implants was 1.37 ± 0.5 mm. For marginal bone loss, there was no statistically significant difference between the two implant lengths (P = 0.38) or diameters (P = 0.34) or between the M and R implant surfaces (P = 0.47). Conclusions: Different implant lengths, diameters, and surface treatments do not appear to influence the prognosis of the implant. Within the limitation that most of the short implants were splinted to longer implants, the reduced length of the fixtures did not worsen the long-term survival of the implant-supported fixed prostheses. [ABSTRACT FROM AUTHOR]

Aim To evaluate the influence of implant positioning into extraction sockets on bone formation at buccal alveolar dehiscence defects. Material and Methods In six Labrador dogs the pulp tissue of the mesial roots of 4P4 was removed and the root canals were filled. Flaps were elevated bilaterally, the premolars hemi-sectioned and the distal roots removed. The implants were placed in contact with either the buccal (test site) or with the lingual (control site) bony wall of the extraction sockets. Healing abutments were affixed and triangular buccal bony dehiscence defects, about 2.7 mm deep and 3.5 mm wide, were then prepared. No regenerative procedures were done and a non-submerged healing was allowed. After 4 months of healing, block sections of the implant sites were obtained for histological processing and peri-implant tissue assessment. Results After 4 months of healing, the bony crest and the coronal border of osseointegration at the test sites were located 1.71 ± 1.20 and 2.50 ± 1.21 mm apically to the implant shoulder, respectively. At the control sites, the corresponding values were 0.68 ± 0.63 and 1.69 ± 0.99 mm, respectively. The differences between test and control reached statistical significance ( P < 0.05). Residual marginal bone defects were found both at the test and control sites. A statistically significant difference between test and control sites was only found at the lingual aspects (depth 2.09 ± 1.01 and 1.01 ± 0.48 mm, respectively). Similar heights of the buccal biological width were observed at both sites (about 5.1 mm). Conclusions The placement of implants in a lingual position of the extraction sockets allowed a higher degree of bone formation at buccal alveolar dehiscence defects compared with a buccal positioning. [ABSTRACT FROM AUTHOR]

Objective: The aim of this cross-sectional study was to determine the clinical outcome and patient satisfaction in subjects treated with mandibular overdentures supported by two implants. Material and methods: One hundred and fifty-nine patients, who received restorative therapy in the edentulous mandible consisting of a bar-retained overdenture supported by two osseointegrated implants in a private clinic in Italy, were recalled for a clinical and radiographic examination. One hundred and forty-one subjects with 280 implants attended the examination. The average follow-up time was 3.9 years. The radiographic examination included assessments of the distance between the implant margin and the most coronal position of bone-to-implant contact at the mesial and distal aspects of each implant. A questionnaire regarding comfort, satisfaction with the treatment, aesthetics, speaking capacity and efficiency in chewing was obtained from each subject. Biological and technical complications were recorded and the number of visits due to complications between the delivery of the prostheses and the re-examination was determined. Results: The results from the examination revealed that the number of lost implants was small and the average marginal bone level around the implants was 0.67 mm apical of the implant margin. The most frequently observed complication was hyperplasia of the mucosal tissue under the bar construction. Few patients experienced loosening of retention. The vast majority of patients reported to be satisfied in relation to the restorative therapy from both functional and aesthetic points of view. Conclusion: Patients with edentulous mandibles may be successfully rehabilitated by means of two implants supporting a bar-retained overdenture. To cite this article: Bressan E, Tomasi C, Stellini E, Sivolella S, Favero G, Berglundh T. Implant-supported mandibular overdentures: a cross-sectional study. Clin. Oral Impl. Res. 23, 2012; 814-819. doi: 10.1111/j.1600-0501.2011.02225.x [ABSTRACT FROM AUTHOR]

To evaluate the influence of magnesium-enriched hydroxyapatite (MHA) (SintLife) on bone contour preservation and osseointegration at implants placed immediately into extraction sockets. In the mandibular pre-molar region, implants were installed immediately into extraction sockets of six Labrador dogs. MHA was placed at test sites, while the control sites did not receive augmentation materials. Implants were intended to heal in a submerged mode. After 4 months of healing, the animals were sacrificed, and ground sections were obtained for histomorphometric evaluation. After 4 months of healing, one control implant was not integrated leaving n=5 test and control implants for evaluation. Both at the test and the control sites, bone resorption occurred. While the most coronal bone-to-implant contact was similar between test and control sites, the alveolar bony crest outline was maintained to a higher degree at the buccal aspect of the test sites (loss: 0.7 mm) compared with the control sites (loss: 1.2 mm), even though this difference did not reach statistical significance. The use of MHA to fill the defect around implants placed into the alveolus immediately after tooth extraction did not contribute significantly to the maintenance of the contours of the buccal alveolar bone crest. Caneva M, Botticelli D, Stellini E, Souza SLS, Salata LA, Lang NP. Magnesium-enriched hydroxyapatite at immediate implants: a histomorphometric study in dogs. Clin. Oral Impl. Res. , 2011; 512-517 doi: 10.1111/j.1600-0501.2010.02040.x [ABSTRACT FROM AUTHOR]