Clinical Oral Implants Research

To compare the amount of newly formed bone after sinus floor augmentation with two different particle sizes of bovine bone mineral (BBM) using clinical, micro-computerized tomography (CT) and histological techniques. Bilateral sinus floor augmentations were performed in 10 patients. Six to 9 months later, bone samples were retrieved and analyzed. Results: Both groups were not different in vertical bone height achieved after augmentation, post-operative complications and maximal torque for the insertion of implants. Micro-CT measurements could not detect a statistically significant difference in bone volume between the groups (with a tendency for new more bone in the small granules group). Histomorphometric analysis revealed that both granule sizes produced the same pattern of bone formation, surrounding the graft granules, and producing a shape of a network, "bridging" between the BBM particles. Multi-nucleated giant cells, probably osteoclasts, were observed directly on the BBM particle surface in both groups. The osteoclast-like cells preferred the small-size BBM particles and not the large particles both in the small-size and the large-size granules group. Both sizes of BBM granules preformed equally and achieved the aim of the sinus floor augmentation procedure clinically and histologically.

The purpose of this study was to evaluate retrospectively, after a period of 6-48 months follow-up of prosthetic loading, the survival rate of 103 zygomatic implants inserted in 55 totally edentulous severely resorbed upper jaws. Fifty-five consecutive patients, 41 females and 14 males, with severe maxillary bone resorption were rehabilitated by means of a fixed prosthesis supported by either 1 or 2 zygomatic implants, and 2-6 maxillary implants. This retrospective study calculated the success and survival rates at both the prosthetic and implant levels. Out of 55 prostheses, 52 were screwed on top of the implants, while 3 were modified due to loss of standard additional implants and transformed in semimovable prosthesis. Although osseointegration in the zygomatic region is difficult to evaluate, no zygomatic implant was considered fibrously encapsulated and they are still in function. This study confirms that zygoma bone can offer a predictable anchorage and support function for a fixed prosthesis in severely resorbed maxillae.

To evaluate fundamental cell functions, such as adhesion, IL-6 production and proliferation of human gingival keratinocytes cultured on a newly engineered collagen matrix (CM-10826) and to assess the degree of specific biocompatibility of this new device. Primary cultures of human keratinocytes were derived “in vitro” from biopsies of independent donors. Their true epithelial origin was ensured by the expression of cytokeratin 14. Adhesion, proliferation and production of IL-6 cytokine was then measured in the presence or absence of CM-10826 activity or of its relevant components. Functional tests revealed that keratinocytes adhered to CM-10826 and up-regulated their basal IL-6 production. The type of keratinocytes used expressed cytokeratin 14. Proliferation experiments demonstrated that the best cellular response was observed in the presence of Collagen I, the main component of CM-10826. No undesired effects were observed as for keratinocyte viability, morphology or differentiation. Our results demonstrate that CM-10826 has a favourable biological effect on the “in vitro” response of gingival keratinocytes in terms of IL-6 production, cell growth and adhesion. These findings may encourage a possible use of this collagen membrane as a tissue which, alone, may substitute for autologous gingival grafts thereby overcoming the limitations of autologous tissue.

To address the criticisms raised by Anitua et al. (European Journal of Oral Implantology, 6, 2013, 9-11) to the article "Plasma Rich in Growth Factors (PRGF) in Human Post-Extraction Sockets: an Histological and Histomorphometric Study.", recently published by Farina and colleagues (Clinical Oral Implants Research 2012; doi: 10.1111/clr.12033). All the methodological aspects criticized in the letter by Anitua et al. were thoroughly reconsidered and discussed in a structured short communication. When indicated, pertinent, additional material was included to reinforce our considerations. As most clinical studies in implant dentistry, including previous studies evaluating the efficacy/effectiveness of PRGF, the study by Farina et al. has some limitations. However, it is currently the only published controlled trial using quantitative parameters related to PRGF-induced early bone formation. Despite all limitations, the results of the study by Farina et al., which were based on different quantitative parameters (micro-CT scan, immunohistochemical markers of wound healing and bone deposition), indicated a limited effect of PRGF on early bone formation in extraction sockets.

Background and aimIn cases with limited bone height, short implants could be a good alternative to augmentation procedures. The aim of this randomized controlled trial was to compare the clinical performance of implants of 6mm or 11mm in length in the posterior region. Materials and methodsIn this multicenter trial (six study sites), 95 subjects were included. Subjects were randomly allocated to receiving implants with lengths of either 6 or 11mm both with a diameter of 4mm (OsseoSpeed 4.0 S; Astra Tech AB; Molndal, Sweden). In all cases, there had to be sufficient bone height to allow placement of an implant of at least 11mm in length. Two or three implants were placed per subject using one-stage surgery with a 42-48days' healing period before loading. They were restored with a screw-retained splinted fixed prosthesis. Clinical and radiographic examinations were performed preoperatively, postsurgery, at loading, and 6 and 12months after prosthesis placement. ResultsA total of 208 implants were inserted in 49 subjects receiving 6-mm implants (test) and in 46 subjects receiving 11mm implants (control). Two 6-mm implants failed before loading and one 6 and 11mm implants failed before 1-year evaluation. From loading to the 12months' follow-up, a mean marginal bone gain of 0.06mm in the 6mm group and 0.02mm in the 11mm group was found (P=0.478). Soft tissue behavior was equal in both groups (Bleeding and plaque [P=1.0] probing depth [P=0.91]). Conclusion One-year data indicate that treatment with the 6mm implants is as reliable as treatment with the 11mm implants. This provides a good treatment option in situations with limited bone height in the premolar and molar regions. Whether or not short implants provide a predictable treatment alternative to bone augmentation procedures remains to be investigated in the future randomized controlled clinical trials.

Objective: The purpose of the present study was to histologically and histomorphometrically evaluate the long-term tissue response to deproteinized bovine bone (DPBB) particles used in association with autogenous bone and to compare particle size after 6 months and 11 years, in the same patients, in order to determine possible resorption. Material and methods: Twenty consecutive patients (14 women and six men) with a mean age of 62 years (range 48–69 years) with severe atrophy of the posterior maxilla were included in this study. Thirty maxillary sinuses with <5 mm subantral alveolar bone were augmented with a mixture of 80% DPBB and 20% autogenous bone. Eleven years (mean 11.5 years) after augmentation, biopsies were taken from the grafted areas of the 11 patients who volunteered to participate in this new surgical intervention. The following histomorphometrical measurements were performed in these specimens: total bone area in percentage, total area of the DPBB, total area of marrow space, the degree of DPBB–bone contact (percentage of the total surface length for each particle), the length of all DPBB particles and the area of all DPBB particles. The length and the area of the particles were compared with samples harvested from the same patients at 6 months (nine samples) and pristine particles from the manufacturer. Results: The biopsies consisted of 44.7±16.9% lamellar bone, 38±16.9% marrow space and 17.3±13.2% DPBB. The degree of DPBB to bone contact was 61.5±34%. There were no statistically significant differences between the length and area of the particles after 11 years compared with those measured after 6 months in the same patients or to pristine particles from the manufacturer. Conclusion: DPBB particles were found to be well integrated in lamellar bone, after sinus floor augmentation in humans, showing no significant changes in particle size after 11 years. To cite this article: Mordenfeld A, Hallman M, Johansson CB, Albrektsson T. Histological and histomorphometrical analyses of biopsies harvested 11 years after maxillary sinus floor augmentation with deproteinized bovine and autogenous bone. Clin. Oral Impl. Res. 21, 2010; 961–970. doi: 10.1111/j.1600-0501.2010.01939.x

To compare the survival and peri-implant bone loss of implants with a fluoride-modified surface in smokers and nonsmokers. Patient files of all patients referred for implant treatment from November 2004 to 2007 were scrutinized. All implants were placed by the same experienced surgeon (B. C.). The only inclusion criterion was a follow-up time of at least 2 years. Implant survival and bone loss were assessed by an external calibrated examiner (S. V.) comparing digital peri-apical radiographs taken during recall visits with the post-operative ones. Implant success was determined according to the international success criteria (Albrektsson et al. 1986). Survival of implants installed in smokers and nonsmokers was compared using the log-rank test. Both nonparametric tests and fixed model analysis were adopted to evaluate bone loss in smokers and nonsmokers. One-thousand one-hundred and six implants in 300 patients (186 females; 114 males) with a mean follow-up of 31 months (SD 7.15; range 24-58) were included. Nineteen implants in 17 patients failed, resulting in an overall survival rate of 98.3% at the implant level and 94.6% at the patient level. After a follow-up period of 2 years, the cumulative survival rates was 96.7% and 99.1% with the patient and implant as the statistical unit, respectively. Implant survival was significantly higher for nonsmokers compared with smokers (implant level P=0.025; patient level P=0.017). The overall mean bone loss was 0.34 mm (n=1076; SD 0.65; range 0-7.1). Smokers lost significantly more bone compared with nonsmokers in the maxilla (0.74 mm; SD 1.07 vs. 0.33 mm; SD 0.65; P<0.001), but not in the mandible (0.25 mm; SD 0.65 vs. 0.22 mm; SD 0.5; P=0.298). The present study is the first to compare peri-implant bone loss in smokers and nonsmokers from the time of implant insertion (baseline) to at least 2 years of follow-up. Implants with a fluoride-modified surface demonstrated a high survival rate and limited bone loss. However, smokers are at a higher risk of experiencing implant failure and more prone to show peri-implant bone loss in the maxilla. Whether this bone loss is predicting future biological complications remains to be evaluated.

The aim of this study was to evaluate the biocompatibility of two different barrier materials in cultures of human osteoblast-like cells (CRL 11372) in vitro. Polylactic acid (Epi-Guide; EG) and collagen membrane (Bio-Collagen, BC) were examined. To analyze the effect of materials on cell proliferation, cell numbers and cell viability, cells were cultured on the barrier membranes for 24 and 72 h. Cells plated on culture dishes (CD) served as positive controls. Cell proliferation rate was assessed by the bromodeoxyuridine (BrdU) immunohistochemical technique. The cell numbers of each well were counted. Cell viability was estimated by counting the number of cells, which excluded trypan blue solution. Scanning electron microscopy (SEM) was used to observe the interactions between osteoblastic cells and barrier membranes. The highest number of BrdU-labeled cells were seen on CD after both of the time periods. In comparison with the other two groups, BC showed significantly fewer cells after both time periods. Regarding cell numbers, after 24 and 72 h of incubations CD showed the highest number of cells. The number of viable cells was similar for all the groups. After 72 h for the EG group, SEM view showed flat cells. After 72-h time periods, the BC group revealed a weak adhesion of cells to the barriers. The results demonstrate that cells were able to proliferate on these materials and EG promoted the proliferation of human osteoblast like cells. We prefer to use the EG membrane.

Objectives To provide a metallurgical and histomorphological analysis of hybrid bridgework and associated dental implants which have been in a clinical load bearing situation for a period of 12.5years. Material and methodsThe physical integrity of the hybrid framework was examined with stereoimaging microscopy and scanning electron microscopy for signs of wear, fatigue cracks, corrosion. Elemental spectra and maps of the surface were analysed with an EDAX((R)) Detecting Unit (AMETEK, Inc, Mahwah, NJ, USA). Similarly, the supporting titanium abutments screwed into the implants were examined for fatigue and corrosion. Bone density scans and bone trabecular patterns were obtained from radiographs. Microcomputer tomography was used to assess the bone-implant interface and bone architecture around the implants. Histological sections were stained with 1% basic fuchsin to assess osseous microdamage. ResultsThe study demonstrated that the gold alloy framework to be in satisfactory condition with little indication of corrosion or cracking. The interface between the gold alloy and the titanium abutments likewise demonstrated no obvious corrosion cells. No radiographic evidence of any adverse loss of bone around the implants was noted. Bone mineral density was related to implant position, being higher between the implants. Scanning electron micrograph images confirmed the good bone integration with the implant threads with a high level of organisation, maturation and adaptation for the entire length of the implant. There was no evidence of any microdamage. Conclusions The implants, abutments and hybrid framework were in remarkably good condition considering their length of service.

to evaluate the edentulous ridge dimensions of maxillary posterior sextants with a tridimensional radiographic technique. The influence of the presence/absence of teeth adjacent to the edentulous site on the dimensions of the edentulous ridge was also evaluated. computerized tomography (CT) scans of 127 patients (65 males and 62 females; mean age: 55.2 ± 10.1 years) with at least one missing tooth in the maxillary posterior sextants were analyzed. On CT cross sections, bone height (BH), bone width (BW) at 1, 3, and 7 mm from the most coronal point of the alveolar crest (BW(1 mm) , BW(3 mm) , and BW(7 mm) , respectively) and the relative vertical ridge position (rVRP) were assessed at the first premolar, second premolar, first molar and second molar edentulous sites. the results of the study indicate that (i) the maxillary sinus was radiographically evident in about 50% of first premolar sites and 90-100% of second premolar and molar sites; (ii) BH showed a significant decrease from first premolar to molar sites; (iii) BW(1 mm) was higher at second molar site compared with the first and second premolar sites, BW(3 mm) and BW(7 mm) were higher at each molar site compared with each premolar site; (iv) the proportion of sites with BH ≥ 8mm and BWI mm ≥ 6mm was 28.3%, 18.4%, 8.0% and 18.2% [corrected] at first premolar, second premolar, first molar and second molar sites, respectively. The absence of teeth adjacent to the edentulous site negatively affected rVRP, but not BH and BW. The results of the study indicate that at premolar and molar sites, [corrected] the dimensions of the alveolar crest may call for bone augmentation procedures for proper implant placement in a substantial amount of edentulous patients. When both mesial and distal tooth adjacent to the edentulous site are absent, the placement of implants of adequate dimensions may be more challenging due to a more apical position of the alveolar ridge compared with sites where both adjacent teeth are present.

Metallic implantation materials having high yield strength, low elastic modulus, and non-cytotoxic alloying elements would be advantageous for the long-term stability of implants. This study assessed the surface and mechanical properties, and also in vitro osteoconductivity of ultrafine-grained (UFG) Ti-13Nb-13Zr alloy produced by dynamic globularization without any severe deformation for future biomedical applications as an endosseous implant material. The surface characteristics and mechanical properties were investigated by orientation image microscopy, contact angle measurements, optical profilometry, and uniaxial tension tests. Mouse calvaria-derived pre-osteoblastic cell (MC3T3-E1) attachment, spreading, viability, alkaline phosphatase (ALP) activity, and quantitative analysis of osteoblastic gene expression on UFG Ti-13Nb-13Zr alloy were compared with coarse-grained (CG) Ti-13Nb-13Zr and CG Ti-6Al-4V alloys. Dynamic globularized Ti-13Nb-13Zr alloy has an ultrafine grain size (0.3 μm) and an excellent combination of yield strength and elastic modulus compared with CG alloys, which displayed significantly lower water contact angles compared with CG alloys (P<0.05). The UFG and CG Ti-13Nb-13Zr alloys displayed significantly increased cellular attachment compared with CG Ti-6Al-4V alloy (P<0.05). The UFG Ti-13Nb-13Zr supported better cell spreading and more numerous focal adhesions. ALP activity (P<0.05) and mRNA expressions of the osteoblast transcription factor genes (osterix, Runx2) and marker gene for osteoblast differentiation (osteocalcin) were markedly increased in cells grown on the UFG substrate compared with CG substrates at early incubation timepoints. Enhanced pre-osteoblast response to UFG Ti-13Nb-13Zr substrate is attributable to the non-cytotoxic alloying elements and the submicron scale grain size contributes to the superior surface hydrophilicity and abundant grain boundaries favorable for cell behavior. These findings indicate that dynamic globularized UFG Ti-13Nb-13Zr alloy is promising for load-bearing endosseous implant material because of excellent mechanical and biological compatibilites.

Aim: The aim of the present prospective study was to evaluate the long-term outcome of implants placed simultaneously with guided bone regeneration (GBR) using resorbable and non-resorbable membranes. Materials and methods: The original study population consisted of 72 patients receiving a total of 265 implants. In all GBR-treated sites, demineralized bovine bone mineral (DBBM) was used in combination either with a collagen (CM) or an Expanded polytetrafluoroethylene (e-PTFE) membrane. A total of 112 implants was treated with CM, 41 implants were treated with e-PTFE membranes, and 112 served as a control group because implants were entirely surrounded by bone and did not need any GBR procedures. Clinical and radiographic analyses were performed after a period of 12-14 years. Results: The median follow-up time was 12.5 years (range 12-14 years). A total of 58 patients participated in the present investigation, corresponding to 80.5% of the original study population. The cumulative implant survival rate at the follow-up examination was 93.2%. For the control group the cumulative survival rate was 94.6%, for the CM 91.9%, and for the e-PTFE 92.6%. Differences among the groups were not statistically significant. The radiographically determined marginal bone level (MBL) amounted to: control 2.36 mm (SD), CM 2.4 mm (SD), e-PTFE 2.53 mm (SD). There is no evidence (P < 0.2) that the slope of bone level over time is different for the three treatment groups. Conclusion: It is concluded that implants placed simultaneously with GBR procedures using resorbable or non-resorbable membranes reveal a high survival rate ranging from 91.9% to 92.6%, therefore it is considered to be a safe and predictable therapy. [Correction added after online publication 30 November 2012: the marginal bone level of CM, e-PTFE, and control was corrected to 'control 2.36 mm (SD), CM 2.4 mm (SD), e-PTFE 2.53 mm (SD)' in the Results section].

In dentistry, allergic reactions to Ti implants have not been studied, nor considered by professionals. Placing permanent metal dental implants in allergic patients can provoke type IV or I reactions. Several symptoms have been described, from skin rashes and implant failure, to non-specific immune suppression. Our objective was to evaluate the presence of titanium allergy by the anamnesis and examination of patients, together with the selective use of cutaneous and epicutaneous testing, in patients treated with or intending to receive dental implants of such material. Thirty-five subjects out of 1500 implant patients treated and/or examined (2002-2004) were selected for Ti allergy analysis. Sixteen presented allergic symptoms after implant placement or unexplained implant failures [allergy compatible response group (ACRG)], while 19 had a history of other allergies, or were heavily Ti exposed during implant surgeries or had explained implant failures [predisposing factors group (PFG)]. Thirty-five controls were randomly selected (CG) in the Allergy Centre. Cutaneous and epicutaneous tests were carried out. Nine out of the 1500 patients displayed positive (+) reactions to Ti allergy tests (0.6%): eight in the ACRG (50%), one in the PFG (5.3%)(P=0.009) and zero in the control group. Five positives were unexplained implant failures (five out of eight). Ti allergy can be detected in dental implant patients, even though its estimated prevalence is low (0.6%). A significantly higher risk of positive allergic reaction was found in patients showing post-op allergy compatible response (ACRG), in which cases allergy tests could be recommended.

Various imaging techniques, including conventional radiography and computed tomography, are proposed to localize the mandibular canal prior to implant surgery. The aim of this study is to determine the incidence of altered mental nerve sensation after implant placement in the posterior segment of the mandible when a panoramic radiograph is the only preoperative imaging technique used. The study included 1527 partially and totally edentulous patients who had consecutively received 2584 implants in the posterior segment of the mandible. Preoperative bone height was evaluated from the top of the alveolar crest to the superior border of the mandibular canal on a standard panoramic radiograph. A graduated implant scale from the implant manufacturer was used and 2 mm were subtracted as a safety margin to determine the length of the implant to be inserted. No permanent sensory disturbances of the inferior alveolar nerve were observed. There were two cases of postoperative paresthesia, representing 2/2584 (0.08%) of implants inserted in the posterior segment of the mandible or 2/1527 (0.13%) of patients. These sensory disturbances were minor, lasted for 3 and 6 weeks and resolved spontaneously. Panoramic examination can be considered a safe preoperative evaluation procedure for routine posterior mandibular implant placement. Panoramic radiography is a quick, simple, low-cost and low-dose presurgical diagnostic tool. When a safety margin of at least 2 mm above the mandibular canal is respected, panoramic radiography appears to be sufficient to evaluate available bone height prior to insertion of posterior mandibular implants; cross-sectional imaging techniques may not be necessary.

Retrospectively evaluate the survival, radiographic and peri-implant outcome of single turned Brånemark™ implants after at least 16 years. From 134 patients (C-group), 101 could be contacted concerning implant survival and 50 (59 remaining implants) were clinically examined (I-group). Marginal bone level was radiographically measured from the implant-abutment junction at baseline (=within 6 months after abutment connection) and 1-4, 5-8 and 16-22 years post-operatively. Probing depth, gingival and plaque index were measured. Marginal bone-level changes were analyzed using Friedman's and Wilcoxon's signed ranks tests. Spearman's correlations between radiographic and clinical parameters were calculated. In the C-group, 13 out of 166 implants in 11 out of 134 patients failed (CSR=91.5%). In the I-group (28 males-22 females; mean age 23.9 years at baseline; range 14-57), the mean follow-up was 18.4 years (range 16-22). The mean bone level was 1.7±0.88 mm (range -0.8 to 5) after 16-22 years. Changes in the mean marginal bone level were statistically significant between baseline and the second measuring interval (1-4 years). Thereafter, no significant differences could be demonstrated. The mean interproximal probing depth, gingival and plaque indices were 3.9±1.27 mm, 1.2±0.81 and 0.2±0.48, respectively. Probing depth was moderately correlated with gingival inflammation (r=0.6; P<0.001) but not with bone level (P>0.05). 81.4% of the implants had a bone level ≤2nd thread and 91.5% had a probing depth ≤5 mm. 76.3% had both bone level ≤2nd thread and probing depth ≤5 mm. The single turned Brånemark™ implant is a predictable solution with high clinical survival and success rates. In general, a steady-state bone level can be expected over decades, with minimal signs of peri-implant disease. A minority (5%), however, presents with progressive bone loss.

The aim of the present study was to evaluate the long-term results of dental implants using implant survival and implant success as outcome variables. Of the 76 patients who received 162 implants of the Straumann Dental Implant System during the years 1990-1997, 55 patients with 131 implants were recalled 10-16 years after implant placement for a complete clinical and radiographic examination, followed by a questionnaire that examined the degree of satisfaction. The incidence of biological and technical complications has been carefully analysed for each implant. Success was defined as being free of all these complications over the entire observation period. Associated factors related to peri-implant lesions were analysed for each implant. The long-term implant cumulative survival rate up to 16 years was 82.94%. The prevalence of biological complications was 16.94% and the prevalence of technical complications was 31.09%. The cumulative complication rate after an observation period of 10-16 years was 48.03%, which meant that substantial amounts of chair time were necessary following implant placement. The majority of implant losses and biological complications were concentrated in a relatively small number of patients. Despite a relatively high long-term survival rate, biological and technical complications were frequent. Patients with a history of periodontitis may have lower implant survival rates than patients without a history of periodontitis and were more prone to biological complications such as peri-implant mucositis and peri-implantitis.

The delivery of growth factors for enhanced osseointegration depends on the effectiveness of the carrier systems at the bone-implant interface. This study evaluated the effect of solo and dual delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2) and recombinant human vascular endothelial growth factor (rhVEGF(165) ) from biomimetically octacalcium phosphate-coated implants on osseointegration. Biomimetic implants, bearing either a single growth factor (BMP or VEGF) or their combination (BMP+VEGF), were established, and compared with acid-etched (AE, control) and biomimetic implants without growth factor (CAP). Implants were placed into frontal skulls of nine domestic pigs. The quality of osseointegration was evaluated using microradiographic and histomorphometric analysis of bone formation inside four defined bone chambers of the experimental implant at 1, 2 and 4 weeks. Biomimetic implants, either with or without growth factor, showed enhanced bone volume density (BVD) values after 2 and 4 weeks. This enhancement was significant for the BMP and BMP+VEGF group compared with the control AE group after 2 weeks (P<0.05). All biomimetic calcium-phosphate (Ca-P) coatings exhibited significantly enhanced bone-implant contact (BIC) rates compared with the uncoated control surface after 2 weeks (P<0.05). However, the combined delivery of BMP-2 and VEGF did not significantly enhance BIC at the final observation period. It was concluded that the combined delivery of BMP-2 and VEGF enhances BVD around implants, but not BIC. Therefore, it may be assumed that changes in the surface characteristics should be considered when designing growth factor-delivering surfaces.

A precise and scientifically established method for the evaluation of the bone quality/primary stability is the measure of the insertion torque (IT). The aim of this study was a comparison between the IT values and the bone-implant contact percentage (BIC) of human implants retrieved after a 4/8-week healing period. Seventeen implants, all with a sandblasted and acid-etched surface, were evaluated in the present study. The implants had been retrieved for different causes, after 4/8 weeks, with a 5 mm trephine bur, and immersed in 10% buffered formalin to be processed for histology. A not statistically significant correlation was found between IT and BIC (P<or=0.892). In the present study on human-retrieved implants, no statistically significant correlation was found between the IT values and BIC. These results could be due to a lack of relationship between bone structure and IT, or to the fact that primary stability may not only be influenced by bone volumetrical density and/or bone trabecular connectivity but also by the thickness and density of the cortical layer. Moreover, the present knowledge of the bone microstructure is not enough to explain the relationship of bone quality and primary implant stability.

This prospective randomized match-paired controlled trial aimed to evaluate the impact of implant platform diameter on marginal bone level around implants restored according to the platform switching (PS) concept. A total of 24 implants were examined in 12 patients. All patients received two adjacent implants inserted at the crestal level: 4.3 mm (control group) and 4.8 mm (test group) in diameter. Mesio-distal implant position was randomly performed. According to the PS concept, for restoration, a 3.8 and 4.3 mm diameter abutment was used, respectively in the control and test groups, resulting, in both groups, with 0.25 mm of implant/abutment mismatching. Implant restorations were splinted. Eighteen months after final restoration, periapical standardized digital radiographs were taken to evaluate marginal bone level alterations after loading. The Wilcoxon Signed-Rank Test was selected to identify differences between groups. At the last follow-up, control implants exhibited a mean bone loss value of 1.10 mm (SD: 0.47 mm); the test group showed a mean value of 1.09 mm (SD: 0.08 mm). No statistically significant differences were found between test and control groups. Within the limits of this study, the present results suggest that bone resorption is mostly related to biologic (biologic width re-establishment) rather than to biomechanical factors (implant platform diameter). Furthermore long-term studies with a wider sample size are needed to confirm the platform diameter influence on hard tissue response around implants restored according to the PS concept.

An association between the long-term success and survival of implant-supported prostheses as a function of biomaterial combinations has not been established. The use of cast cobalt-chromium for the suprastructure framework may be an alternative to the conventional approach of using type 3 gold alloys. A retrospective chart audit of all patients who had received implant-supported fixed dental prostheses (FDP) before 1996 was identified in a private practice clinic. Data were recorded for FDPs made from four combinations of alloy frameworks and veneering material, i.e. type 3 gold and cobalt-chromium with ceramic or prefabricated acrylic teeth. The extracted data from the charts were subjected to explorative statistical tests including Kaplan-Meier survival analyses. Patients (n=198) with 270 short and extensive FDPs supported entirely by 1117 implants were identified. The average follow-up observation periods varied between 4 and 220 months, with an average of 120 months. The success and survival, as well as event rates and types of biological and technical complications, were similar for implant-supported FDPs using cobalt-chromium and type 3 gold alloy frameworks veneered with ceramics or prefabricated acrylic teeth. An influence of the suprastructure biomaterial combination on the clinical performance of the individual supporting implants could not be established. Implant-supported FDPs made from type 3 gold or cobalt-chromium frameworks and veneered with ceramic or prefabricated acrylic teeth demonstrate comparable clinical performance. The biomaterial combinations do not appear to influence the success or survival of the individual implants.

(i) To evaluate the survival and success rates of the new Roxolid narrow diameter implant placed in horizontally deficient ridges; and (ii) to evaluate the incidence of prosthetic complications. In a 24-month period (2009-2010) 18 partially or totally edentulous patients received 51 Straumann Roxolid (13 tissue level, 38 bone level) implants. Prosthetic loading of implants was either immediate (four implants; one patient) or delayed (2-12 months after placement; 47 implants; 17 patients). The patients were rehabilitated with either fixed (16 patients; 45 implants) or removable (two patients; six implants) prostheses. All implants successfully achieved osseointegration and all patients completed the planned prosthetic rehabilitation. Peri-implant bone resorption values ranged from 0 to 1 mm at the end of the observation period (range: 3-19 months). Implant survival and success rates were therefore 100%. No prosthetic complications occurred and all implants are still in function; therefore the prosthesis success rate was 100%. Narrow diameter implants fabricated with the new titanium-zirconium alloy were demonstrated to be reliable in supporting both fixed and removable prosthetic rehabilitations in horizontally deficient ridges. Implant survival, peri-implant bone resorption, and prosthetic complication rates were consistent with those reported in the literature for standard diameter implants placed in non-deficient edentulous ridges.

A clinical and radiographical study was performed to compare the outcome of oral rehabilitation in the edentulous mandible by fixed supraconstructions connected to implants installed according to either i) a 1-stage surgical procedure and immediate loading (Experimental Group-EG), or ii) the original 2-stage concept (Reference Group-RG). The EG comprised 16 subjects with edentulous mandibles. Beyond the non-smoking criteria the following specific inclusion criteria were adopted: i) all patients had to consider themselves to be in good general health, ii) the amount of bone had to enable the installation of 5-6, at least 10 mm long fixtures to be bicortically anchored (Mk II fixtures; Nobel Biocare AB, Göteborg, Sweden) between the mental foramina, and iii) the patients had to be available for the follow-up and maintenance programme. A total of 88 implants were placed in the EG (16 patients) compared to 30 in the RG (11 patients). In the EG, fixed appliances were connected to the implants within 20 days following implant installation while the fixed appliances in the RG were connected about 4 months following fixture installation. At the time for delivery of the supraconstructions all 27 patients were radiographically examined, an examination that was repeated at the 18-month follow-up. The analysis of the radiographs from the EG disclosed that during the 18-month observation period the mean loss of bone support amounted to 0.4 mm. The corresponding value observed in the RG was 0.8 mm. During the 18-month observation period no fixture was lost in any of the 2 groups examined. The implants under study as well as those in the reference material were at all observation intervals found to be clinically stable. The present clinical study demonstrated that it is, at least based on an 18-month observation period, possible to successfully load titanium dental implants immediately following installation via a permanent fixed rigid cross-arch supraconstruction. However, such a treatment approach has so far to be strictly limited to the inter-foramina area of the edentulous mandible.

The purpose of this study was to determine the percentage of 'bone area' (BA) and 'bone-to-implant contact' (BIC) of dental implants with different designs and surface modifications after functional loading. Three types of dental implants with fixed partial dentures were placed in the posterior jaws of adult baboons (commercially pure titanium (CpTi) screws, grit-blasted acid-etched (GBAE) screws, and titanium plasma-sprayed (TPS) cylinders), three of the same design per quadrant. After 18 months of functional loading, all implants investigated were successfully integrated in the jawbone and histologic and histomorphometric analyses were carried out. Statistical evaluation was performed with a mixed model with data given as least-square means and standard errors of the mean (SEM). Histologically, direct BIC without connective tissue interposed between implant surfaces and peri-implant bone was seen. Analysis of BA within 1 mm around implants showed significant differences between CpTi (50.5%) and TPS (39.7%) (+/-2.72 SEM; P<0.01) in the maxilla. To account for the different implant designs, absolute BIC was calculated. Significant differences were found between CpTi (23.9 mm) and TPS (15.1 mm) and between GBAE (27.2 mm) and TPS (15.1 mm) (+/-1.05 SEM; P<0.01) in the maxilla and between GBAE (26.5 mm) and TPS (19.6 mm) (+/-1.42 SEM; P<0.01) in the mandible. Overall, the data indicate that, in the maxilla, screw-shaped implants showed more absolute BIC than cylindrical implants, which had less maxillary than mandibular absolute BIC after 18 months of functional loading.

A clinical and radiographical study was performed to evaluate the treatment outcome of single tooth replacements with artificial crowns retained to implants installed according to a 1-stage surgical procedure and immediate loading (Experimental Group = EG) in comparison to the original 2-stage concept (Control Group = CG). The EG comprised 14 patients (= 14 implants) and the CG comprised 8 patients (= 8 implants), all with single tooth losses anterior to the molars. Beyond the non-smoking criterion the following criteria were adopted: i) the amount of bone had to allow for installation of a fixture with a minimum length of 13 mm and Ø = 3.75 mm, ii) the jaw relationship had to allow for bilateral occlusal stability, iii) the patients should be judged to be non-bruxers, and iv) the patients had to be available for the follow-up and maintenance programme. In the EG a temporary crown was connected to the implant within 24 h following fixture installation. Six months later this crown was replaced with a permanent one. In the CG the surgical and prosthetic treatment followed the standard protocol. Out of the 14 fixtures in the EG 2 were lost up to 5 months in function and were subsequently removed. All remaining 12 implants were stable at every subsequent follow-up examination. No fixture losses were recorded in the CG and all implants in this group were stable at the follow-ups. At the 6-month observation interval all the participating 20 patients were radiographically examined, an examination that was repeated at the 18-month follow-up. The analysis of the radiographs from the EG as well as from the CG disclosed that during the 12-month observation period the mean change of bone support was about 0.1 mm. Further studies, designed as controlled multicenter ones, have to be performed before the results of this pilot study can be recommended for more general use.

Objective The aim of this study was to evaluate the effect of scan mode of the cone beam computed tomography (CBCT) in the preoperative dental implant measurements. Material and methodsCompletely edentulous mandibles with entirely resorbed alveolar processes were selected for this study. Five regions were selected (incisor, canine, premolar, first molar, and second molar). The mandibles were scanned with Next Generation i-CAT CBCT unit (Imaging Sciences International, Inc, Hatfield, PA, USA) with half (180 degrees) and full (360 degrees) mode. Two oral radiologists performed vertical measurements in all selected regions; the measurements of half of the sample were repeated within an interval of 30days. The mandibles were sectioned using an electrical saw in all evaluated regions to obtain the gold standard. The intraclass correlation coefficient was calculated for the intra- and interobserver agreement. Descriptive statistics were calculated as mean, median, and standard deviation. Wilcoxon signed rank test was used to determine the correlation between the measurements obtained in different scan mode with the gold standard. The significance level was 5%. ResultsThe values of intra- and interobserver reproducibility indicated a strong agreement. In the dental implant measurements, except the bone height of the second molar region in full scan mode (P=0.02), the Wilcoxon signed rank test did not show statistical significant difference with the gold standard (P>0.05). Conclusions Both modes provided real measures, necessary when performing implant planning; however, half scan mode uses smaller doses, following the principle of effectiveness. We believe that this method should be used because of the best dose-effect relationship and offer less risk to the patient.

The aim of this investigation was to study the acceptance and the rejection of patients referred for single implant restorations based on data from referral, case history, clinical examination and therapy planning. The referrals comprised 184 patients with 251 missing single teeth. Sixty-four per cent of the referred patients were accepted for treatment. There was a difference in acceptance between men and women (75% and 54%, respectively). A negative relationship was noticed between age and acceptance. External trauma (33%), root fractures (16%) and congenitally missing teeth (15%) were the main reasons for lost or missing teeth. Anatomical limitations was the most frequent reason for rejection (76%). Most fillings and crowns on adjacent teeth to the edentulous space did not serve as a contraindication for an implant single-tooth restoration, and thus extensive fillings or not acceptable crowns was the cause of rejection only for a minor group (13%). The great majority of the partially dentate patients showed a very high interest in treatment with single-tooth implants, but some of the patients (4% in all, 11% of those rejected for treatment) did not want implant treatment after having received further information at the specialist clinic.

New technology coupled with a better understanding of tissue biology has played a key role in restoring the somewhat tarnished image of implant dentistry. Thanks to carefully conducted longitudinal studies, it has now become clear that the replacement of missing teeth by artificial implants integrated into the living tissues of the jaws is a predictable procedure, as long as certain guidelines are followed in the manufacture of the implant, in its placement, in its eventual functional loading, and in its maintenance (Adell et al. 1981, Aibrektsson 1988, Albrektsson et al. 1988, Babbush et al. 1986, Kirsch & Mentag 1986, Smithloff 1986,Smithloff & Fritz 1987). Yet, functional success for a natural tooth is dependent on a number of anatomic, physiologic, and environmental considerations which differ in some important respects from those that insure the functional success of an implant. In this paper, we review theanatomic features of the natural dentition with emphasis on the periodontal tissues, and contrast these characteristics with those that exist 1 around well‐integrated endosseous implants.

This study evaluated the survival rate and the clinical, radiographic and prosthetic success of 1920 Morse taper connection implants. One thousand nine hundred and twenty Morse taper connection implants were inserted in 689 consecutive patients, from January 2003 until December 2006. Implants were clinically and radiographically evaluated at 12, 24, 36 and 48 months after insertion (mean follow-up per implant: 25.42 months). Modified plaque index (mPI), modified sulcus bleeding index, probing depth (PD) and the distance between implant shoulder and first crestal bone-implant contact (DIB) were measured in mm. Success criteria included the absence of suppuration and clinically detectable implant mobility, PD<5 mm, DIB<1.5 mm after 12 months of functional loading and not exceeding 0.2 mm for each following year, the absence of recurrent prosthetic complications at the implant-abutment interface. Prosthetic restorations were fixed partial prostheses (364 units), single crowns (SCs: 307 units), fixed full-arch prostheses (53 units) and overdentures (67 units). The overall cumulative implant survival rate was 97.56% (96.12% in the maxilla and 98.91% in the mandible). The cumulative implant success rate was 96.61% (95.25% in the maxilla and 98.64% in the mandible). Only a few prosthetic complications were reported (0.65% of loosening at implant-abutment interface in SCs). The use of Morse taper connection implants represents a successful procedure for the rehabilitation of partially and completely edentulous arches. The absence of an implant-abutment interface (microgap) is associated with minimal crestal bone loss. The high mechanical stability significantly reduces prosthetic complications.

In 1998 and 1999, the ITI DENTAL IMPLANT SYSTEM underwent its greatest modification since it came into existence. Prosthetic possibilities with regard to implant position transfer and master-cast manufacturing have been considerably enlarged by synOcta, surgical instruments have been improved in a multitude of ways and, by introducing SLA, the sand-blasted, large grit, acid-etched surface for oral implants which shortens time to loading by 50%, the ITI and Straumann have achieved a major breakthrough in surface technology.

To assess possible relationships between peri-implant crevicular fluid (PICF) volumes, biochemical markers of the peri-implant immune response, and periodontitis-associated genotype. PICF samples from 29 implant maintenance patients, 24 wearing overdentures, five having single crowns and bridgework (11 patients with peri-implantitis and 18 individuals with healthy peri-implant conditions), were analyzed for per site and per crevicular-fluid-volume concentrations of interleukin-1beta, plasminogen activator inhibitor type 2, and prostaglandin E2 by ELISA. Associations between the three substance concentrations and to crevicular fluid flow rate were analyzed by linear regression analysis. The possible differentiating influence of the composite interleukin-1A and -1B genotype on the patients' peri-implant health and biochemical inflammatory status was checked formally with t-test statistics and the Wilcoxon' test. One implant per patient was chosen for analysis. In patients with healthy peri-implant conditions, genotype-positive individuals showed elevated crevicular fluid flow rates and at the same time reduced mediator concentrations. In patients with an implant affected from peri-implantitis, no statistically significant influence of the periodontitis-associated genotype around the fixture can be stated. There was no statistical difference between per site and per crevicular-fluid-volume concentration analyses. All three mediator concentrations were positively related to each other, while there was a strong negative correlation between crevicular fluid volume and plasminogen activator inhibitor 2 or prostaglandin E2. The Interleukin-1 polymorphism investigated exerted only little influence on the peri-implant crevicular immune response, and this influence appeared to be of limited impact in sites with established peri-implantitis lesions.

Interleukin (IL)-1alpha, IL-1beta and their natural specific inhibitor IL-1 receptor antagonist (IL-1ra) play a key role in the regulation of the inflammatory response in periodontal tissues. Polymorphisms in the IL-1 gene cluster have been associated with severe adult periodontitis. We aimed to investigate the IL-1 gene cluster polymorphisms in patients with peri-implantitis. The study included 120 North Caucasian individuals. A total of 71 patients (mean age 68 years, 76% smokers) demonstrating peri-implantitis at one or more implants as evidenced by bleeding and/or pus on probing and bone loss amounting to >3 threads on Brånemark implants and 49 controls (mean age 66 years, 45% smokers) with clinical healthy mucosa and no bone loss around the implants were recruited for the study. The titanium implants, ad modum Brånemark, had been in function for at least 2 years. Mouthwash samples were collected and used for genotyping of the bi-allelic polymorphisms IL-1A(-889), IL-1B(+3953), IL-1B(-511) and a variable number of tandem repeat IL-1RN gene polymorphisms using PCR technique. Significant differences were found in the carriage rate of allele 2 in the IL-1RN gene between peri-implantitis patients and controls (56.5% vs. 33.3%, respectively; odds ratios (OR) 2.6; 95% confidence interval (CI) 1.2-5.6; P=0.015). Logistic regression analysis taking smoking, gender and age into account confirmed the association between the IL-1RN allele 2 carriers and peri-implantitis (OR 3; 95% CI 1.2-7.6; P=0.02). Our results provide evidence that IL-1RN gene polymorphism is associated with peri-implantitis and may represent a risk factor for this disease.

The aim of this systematic review was to assess the methodological and statistical quality of randomised controlled trials of treatment interventions of dental implant surgery and prosthodontics published between 2004 and 2008. Randomised controlled trials were identified following detailed searches of Medline, EMBASE, CINHAL and the Cochrane Central Register of Controlled Trials. Identified studies were independently assessed by two non-blinded reviewers for 14 key methodological and statistical domains. Information was collected using a customised data collection sheet. The initial Medline search yielded 1484 studies. Following application of inclusion criteria 38 randomised controlled trials, not presenting the same patient material, were identified for this review. Inter-examiner agreement was assessed for all domains (median κ score 0.7). All disagreements were resolved by discussion. Randomisation was adequate in 16 trials (42%), allocation concealment was adequate in seven trials (18%) and outcome assessment was blind in 12 trials (31%). Seven trials (18%) tested the intra/inter-examiner reliability of at least one outcome of interest. Confidence intervals were reported in two trials (5%). Seventeen different statistical tests were used. However, inferential statistical analysis was considered appropriate in only 22 trials (57%). Randomised controlled trials of treatment interventions of dental implant surgery and prosthodontics published between 2004 and 2008 are poorly reported and, by themselves, provide little unbiased evidence to support the clinical decisions that we make.

The aim of this study was to test the hypothesis that recombinant human growth and differentiation factor-5 (rhGDF-5) enhances bone formation in sinus floor augmentations in miniature pigs. The maxillary sinus floors in 12 adult female Goettingen minipigs were augmented with beta-tricalcium phosphate (beta-TCP) on one side. The contralateral test side was augmented using two concentrations of rhGDF-5 (400 microg rhGDF-5/g beta-TCP; 800 microg rhGDF-5/g beta-TCP) delivered on beta-TCP (six animals each). One dental implant was inserted into each sinus floor augmentation. After 4 and 12 weeks, histological and histomorphometric assessment of non-decalcified histological specimens was performed. The results showed significantly higher mean values of volume density (VD) of newly formed bone using the concentration of 400 microg/g beta-TCP (22.8%) compared with the respective control (8%) after 4 weeks (P=0.05). The bone-to-implant contact rates were also significantly enhanced after 4 weeks between test sites (400 microg: 41.9%; 800 microg: 40.6%) and control sites (400 microg: 7.8%; 800 microg: 16.4%) (400 microg: P=0.024; 800 microg: P=0.048). It is concluded that rhGDF-5 delivered on beta-TCP significantly enhanced early bone formation compared with beta-TCP alone in sinus lift procedures in miniature pigs.

The task of this working group was to analyze biological, technical and aesthetic complications of single crowns on implants and fixed dental prostheses with or without cantilevers on implants over 5 years or more. In addition, the group analyzed economic aspects on such implant treatment. A systematic search of the relevant literature was conducted and critically reviewed. Four manuscripts were presented to cover the topics. The consensus statements prepared by the group and later accepted at the plenary session as well as suggestions for future research are presented in this article. The four reviews by Jung et al., Pjetursson et al., Romeo & Storelli and Scheuber et al. are printed separately and present detailed analyses of the research topics.

The task of this working group was to update the existing knowledge base regarding the prevalence of peri-implant tissue destruction, the role of occlusal overload, and the outcome of non-surgical and surgical treatment. The literature was systematically searched and critically reviewed. Four manuscripts were presented in key areas deemed to be essential for the current understanding of the magnitude of the clinical entity peri-implantitis. The role of overload as an etiological component was reviewed. Also available data on the results from non-surgical and surgical interventions for the control of tissue destruction were presented. The consensus statements following plenary session approval, clinical implications, and directions for future research based on the group discussions are presented in this article. The results and conclusions of the systematic review process are presented by the respective authors in the subsequent papers.

This group was assigned the task to review the current knowledge in the areas of implant connections to abutments/reconstructions, fixation methods (cement vs. screw retained) for implant-supported reconstructions, as well as the optimal number of implants for fixed dental prosthesis and implant-supported overdentures. The literature was systematically searched and critically reviewed. Four manuscripts were produced in the four subject areas based on systematically search strategy and consensus statements, clinical recommendations and implication for future research were formulated. The following four position papers were the basis for the consensus statements, the clinical recommendations and directions for future research: The remit of this working group was to update the existing knowledge in the areas of reconstructions on implants. The group acknowledged the results of previous workshops and systematic reviews were provided by the following position papers:

A multicenter retrospective study has been conducted on 226 patients necessitating an implant-supported overdenture in the lower jaw. The patients were provided with 904 osseointegrated implants inserted in the interforaminal area of the mental symphisis (4 implants per patient). 4 titanium implant systems were used: TPS and ITI screw implants (Straumann Institute, Waldenburg, Switzerland); Ha-Ti screw implants (Mathys Dental Implants, Bettlach, Switzerland); NLS screw implants (Friatec, Mannheim, Germany). Immediately after implant placement, a U-shaped gold bar was fabricated and implants were immediately loaded with an implant-retained overdenture. Out of 226 patients treated, 194 were followed from a minimum of 2 years to a maximum of 13 years, with a mean follow-up of 6.4 years, whereas 32 patients dropped out during follow-up. The overall failure rate of implants was 3.1% (24/776 implants), whereas the failure rate of bars was 1.5% (3/194 bars). Results from this study showed that the success rate of immediately loaded implants is similar to that obtained in the case of delayed loading, after osseointegration has taken place. In contrast, this method shortens dental rehabilitation times with relevant satisfaction for patients.

Ultra-sonic bone surgery (USBS) has been recently introduced as a novel osteotomic technique. This clinical study reports on the application of this new technique to perform ridge-split procedures. Over a period of 3.5 years, 57 patients underwent a split-crest procedure with the aim to place 230 implants, 78 in the mandible and 152 in the maxilla, in order to rehabilitate nine full arches, three hemi-arcades, 43 partial bridges and 24 single crowns. The initial ridge width varied between 1.5 and 5 mm, average was 3.2 mm. The final width of the ridge ranged from 4 to 9 mm, average was 6 mm. The split length varied between 4.5 and 40 mm, average was 15 mm. Inserted implants were 3.25-5 mm in diameter however most of them (82.4%) were standard implants of 3.75 mm; implant length was classically 10-13 mm. Two hundred and twenty-eight (99.1%) out of the 230 planned implants were placed, the two non-suitable sites were in the maxilla. In the mandible, the ridge augmentation procedure was drastically eased by performing a basal longitudinal discharge notch. At second stage surgery, eight implants failed to osseointegrate; the success rate for the placed implants was 96.5%. All implants have been loaded for at least 2 months and no implant was lost after loading. One hundred and eighty-one and 77 implants have been loaded for at least 6 and 12 months, respectively. The 3-year life-table analysis of loaded implants showed a cumulative survival rate of 100%. The split-crest procedure performed with USBS showed to be safe and comfortable.

In the present multi-center study, non-submerged ITI implants were prospectively followed to evaluate their long-term prognosis in fully and partially edentulous patients. In a total of 1003 patients, 2359 implants were consecutively inserted. Following a healing period of 3-6 months, the successfully integrated implants were restored with 393 removable and 758 fixed restorations. Subsequently, all consecutive implants were documented annually up to 8 years. At each examination, the clinical status of all implants was evaluated according to predefined criteria of success. Therefore, the data base allowed the evaluation of 8-year cumulative survival and success rates for 2359 implants. In addition, cumulative success rates were calculated for implant subgroups divided per implant type, implant length, and implant location. Furthermore, the actual 5-year survival and success rates could be determined for 488 implants. During the healing period, 13 implants did not successfully integrate, whereas 2346 implants fulfilled the predefined criteria of success. This corresponds with an early failure rate of 0.55%. During follow-up, 19 implants were classified as failures due to several reasons. In addition, 17 implants (approximately 0.8%) demonstrated at the last annual examination a suppurative periimplant infection. Including 127 drop out implants (= 5.4% drop out rate) into the calculation, the 8-year cumulative survival and success rates resulted in 96.7% and 93.3%, respectively. The analysis of implant subgroups showed slightly more favorable cumulative success rates for screw type implants (> 95%) compared to hollow-cylinder implants (91.3%), and clearly better success rates for mandibular implants (approximately 95%) when compared to maxillary implants (approximately 87%). The actual 5-year survival and success rates of 488 implants with 98.2% and 97.3%, respectively, were slightly better than the estimated 5-year cumulative survival and success rates of 2359 implants indicating that the applied life table analysis is a reliable statistical method to evaluate the long-term prognosis of dental implants. It can be concluded that non-submerged ITI implants maintain success rates well above 90% in different clinical centers for observation periods up to 8 years.

To evaluate the demographic, radiological and therapeutic parameters that influence the overall clinical performance of palatal implants subjected to orthodontic loading. The data of all patients who had received an orthodontic palatal implant for skeletal anchorage between January 1998 and December 2007 were reviewed retrospectively. The primary endpoint was the implant loss. The following parameters were assessed by univariate (log-rank test) and multivariate (Cox's regression) analysis: (a) age and gender, (b) vertical bone height along the prospective implant axis, (c) surgeon's experience and (d) implant type. Two-hundred and thirty-nine palatal implants were inserted in patients aged between 10 and 65 years. In all, 11/239 (4.6%) implants were lost: nine during the healing phase and two under functional loading. On univariate analysis, "surgeon's experience" was associated with a better implant survival and vice versa (P=0.0005; log-rank test). The significance of "surgeon's experience" was confirmed by Cox's regression analysis (P=0.001; Wald test). All other parameters had no impact on implant loss. The survival probability of palatal implants is not related to demographic and radiological parameters. Implant losses mainly occurred early in the healing phase of the palatal implant. According to our data, "surgeon's experience" is the cornerstone of palatal implant success.

The present follow-up study evaluated clinical and radiographic parameters of dental implants placed with simultaneous guided bone regeneration with expanded polytetrafluoroethylene (e-PTFE) membranes. All implants were functioning well 24 months after insertion. In all, 63 patients with a total of 91 e-PTFE-augmented implants were integrated in a regular maintenance protocol. Modified periodontal data of 85 implants in 59 patients were recorded at 24 months and indicated no difference to implants placed in sufficient pristine bone. The mean plaque score (mplI) was 0.29, 74% of the sites showed no plaque. The sulcular probing depth ranged from 1 to 7 mm with a mean of 2.6 mm (SD +/- 0.8). Of the sites 96.5% were < or = 4 mm deep, in 49% of them probing resulted in bleeding. Periotest values 6 and 24 months (mean: -3.4 and -3.4) after placement revealed stable peri-implant conditions and sustained osseointegration. The radiographic evaluation performed 6, 12 and 24 months post insertion yielded a mean bone loss of 0.93, 1.36 and 1.51 mm ranging from 0 to 4 mm. The short-term results of our clinical study demonstrated stable peri-implant conditions 2 years after membrane-protected osseous regeneration. The newly formed bone seemed to be able to withstand functional loading in a predictable manner after 18 months.

The present study aimed at evaluating the marginal bone resorption and the peri-implant tissue conditions around Narrow-Neck ITI implants in the implant-prosthetic treatment of the agenesis of maxillary lateral incisors. Thirty patients affected by monolateral or bilateral agenesis of the maxillary lateral incisors were selected. Thirty-four ITI-SLA Narrow Neck implants were inserted and loaded about 4 months after the surgical procedure. The final restorations were realized using Aureo Galvan Crowns veneered with feldspathic ceramics. The follow-up period ranged from 24 to 39 months. Both marginal bone resorption and soft tissue quality were evaluated. The data were statistically analysed using analysis of variance (ANOVA) for repeated measures, one-way ANOVA and Tukey's post hoc test (P=0.05). During the 24-39-month follow-up period, no implant showed either pain and sensitivity or mobility. After 39 months of functional loading, a cumulative survival rate of 97.06% and a cumulative success rate of 94.12% were calculated. In case of maxillary lateral incisor agenesis, the implant-prosthetic approach has proved to be a reliable and predictable treatment for both re-establishment of function and aesthetics. Satisfactory values of marginal bone resorption over time and optimal conditions of peri-implant tissue around Narrow-Neck ITI implants were found.

Implants made from a new titanium-zirconium (TiZr) alloy (Roxolid) have shown good osseointegration with no adverse effects in animal studies. This single-cohort pilot study was performed to evaluate the performance and safe use of reduced-diameter implants made from this new TiZr alloy for the first time in human subjects, in a prospective case-controlled series. In two private specialist clinics, each of 22 patients received one 3.3 mm TiZr test implant with a Regular Neck Standard Plus design. The use of the new implant was restricted to the indications and protocol for the use of the existing 3.3 mm diameter regular-neck implant made from Grade IV titanium. The test implants were splinted to a standard Grade IV titanium Regular Neck implant with a fixed dental prosthesis. Twenty of 22 patients had a successful and surviving implant at the 2-year follow-up; one study implant was lost 80 days after placement due to infection spreading from an adjacent tooth and one patient did not complete the 2-year assessment. The mean change in the functional bone level 2 years after loading was -0.33 ± 0.54 mm (-0.32 ± 0.61 mm and -0.34 ± 0.63 mm mesial and distal, respectively). Patients had healthy peri-implant soft tissues, as indicated by mean probing pocket depths ranging from 2.21 to 2.89 mm after 2 years. Within the limits of this pilot study, the performance of the new implant material was safe and reliable. The new implants meet established success and survival criteria after 2 years.

Aim of this prospective case series was to evaluate the outcome of immediately provisionalized single-piece zirconia implants. A total of 20 zirconia implants were inserted in single-tooth gaps in the maxilla (11) and mandible (9) of 20 patients. Implants were restored with all-ceramic CAD/CAM provisionals without occlusal contacts immediately after placement. Permanent all-ceramic restoration was performed 4 months after surgery. Plaque index (PI), bleeding on probing (BOP), Periotest® (PV), pink aesthetic score (PES), mean radiographic marginal bone levels (MBL), implant survival and success were evaluated up to 24 months. Assessment of PI at baseline and follow-ups after 6, 12, 18 and 24 months revealed 27% (±5.3), 24% (±6), 23% (±6.1), 23% (±5.3) and 22% (±6.4), respectively. Evaluation of BOP revealed 25% (±5.6), 21% (±6), 21% (±7.2), 18% (±5.9) and 15% (±5.5), respectively. Implants presented stable at follow-ups (PV). PES improved, but not statistically significant from 8.13 (±1.5) at baseline to 10 (±2) 24 months after implantation. Measurements of MBL showed a significant bone loss of 1.01 mm within the first year after placement (P < 0.001) and 1.29 mm 24 months post-implant insertion, not reaching further statistically significant levels (P > 0.05). One implant was lost 4 months after placement, resulting in a survival and success rate of 95%. Clinical and radiographic parameters demonstrated a 95% integration of immediately loaded zirconia single-piece implants. A long-term randomized-controlled clinical trial was initiated to confirm evidence of this protocol.

To evaluate the clinical performance of provisional screw-retained metal-free acrylic restorations in an immediate loading implant protocol. Two hundred and forty-two consecutive patients were selected retrospectively, who received 1011 implants and 311 immediate provisional screw-retained implant restorations (2-4 h after implant surgery). The patients were monitored for a period of 2-3 months, until they were referred for a final restoration. The primary variables recorded include the survival time and the appearance of fractures in the provisional restoration, and the independent variables included age, sex, dental arch, type of restoration, type of attachment and components used, as well as cantilevers and opposing dentition. A survival analysis (Kaplan-Meier) and a Cox regression analysis were performed. Twenty-three restorations in 20 patients (8.26%, 95% CI 4.8-11.7) showed at least one fracture (7.39%). More than half of the new fractures (52%, 12 cases) occurred in the first 4 weeks. The cumulative survival probability observed was greater in mandible (P=0.05) and non-cantilever restorations (P=0.001), and in those opposed by full restorations or natural teeth (P=0.001). With an opposing implant-supported prosthesis, the risk of fracture was multiplied by 4.7, and the use of cantilevers as well as the location of the restoration in the maxilla multiply the risk by 3.4-3.5. Immediate provisional screw-retained metal-free implant-supported restorations can be considered a reliable restoration (92.6% remain intact) for the healing period of 3 months.

To assess the stability of the peri-implant bone, the peri-implant soft tissues and the esthetic success of immediately placed implants. In this retrospective study, scalloped-shaped implants were placed immediately and 1.5 mm supracrestally after single-tooth extraction. All implants were immediately restored with an implant-supported temporary crown. Clinical and radiographic parameters were assessed on the day of tooth extraction with subsequent implant placement and temporization, after 6 months at delivery of the final crown, and after 1, after 3, and up to 5 years after crown delivery. All 31 implants were clinically successful and in function during the observation period (mean 3.4 years). The peri-implant soft tissues were clinically healthy as indicated by a low mean plaque (below 0.5) and sulcus bleeding index (below 0.24) values. The distance between the implant shoulder and the first visible bone-to-implant contact (DIBrx) was measured at the mesial and distal aspects of each implant using periapical radiographs. Mean values for DIBrx of 1.73 ± 0.59 mm directly after implant placement and 2.25 ± 0.66 mm after the observation period demonstrated stable peri-implant bone levels. The mean distance from the implant shoulder to the gingival margin on the labial aspect (DIM vestibular) was 2.21 ± 1.09 mm directly after implant placement. Respective values at 1 year, at 3 years and at 5 years after crown delivery remained stable thus demonstrating little if any gingival recession. The assessed mean values for the pink (PES) and white (WES) esthetic score (0 = 0–33% score, 1 = 34–66% score, 2 = 67–100% score) were 8/4 directly after implant placement and 9/10 after 1.5–5.5 years of observation. After an observation time of 1.5–5.5 years all implants demonstrated very stable soft tissue levels with little if any recession on mesial, distal and labial aspects and an esthetic score that was reasonable directly after temporization and developed toward maximum scores over time.

Immediate implant placement after tooth extraction is a successful treatment modality. Primary flap closure is important for satisfactory final results in these procedures. The purpose of this article was to evaluate a surgical approach that would enable predictable primary soft tissue closure over implants placed into fresh extraction sockets. In 24 patients, 26 consecutive implants were placed immediately following extraction of one anterior or premolar maxillary tooth. Primary closure was achieved by a surgical technique based on a rotated palatal flap (RPF), covering the implant. Deproteinized bovine bone was used as grafting material. The apicocoronal distance between the buccal alveolar crestal bone and the coronal aspect of the implant body was measured at time of implant placement (mean 2.6 mm, SD 1.72) and at second stage surgery (mean 0.6 mm, SD 0.70). The difference between both records was calculated. The mean gain in crestal bone was 2.0 mm (SD 1.69, P < 0.001). In 1 patient, where the implant cover screw became exposed early, crestal bone loss was noted. This technique offers a predictable valuable treatment approach to achieve and maintain primary soft tissue coverage and crestal bone regeneration over implants immediately placed within a bony envelope, after extracting maxillary teeth, without the use of barrier membranes.