Search

Objective: To assess the clinical, radiographic and patient‐reported outcomes (PROMs) of posterior zirconia and titanium implants at 1 year of implant loading. Materials and Methods: Forty‐two patients with two adjacent missing teeth were enrolled in a randomized controlled trial with a within‐subject controlled design. Each patient received one zirconia (Zr) and one titanium (Ti) implant, with the mesial and distal positions randomized. The implant restoration consisted of multiple layered zirconia, with the buccal aspect veneered. In group Zr, the restoration was intraorally cemented onto the one‐piece Zr implant, whereas in group Ti, the restoration was extraorally cemented onto the titanium base abutment and intraorally screw‐retained onto the Ti implant. Examinations were performed following restoration delivery at baseline (BL) and at 1 year. Measurements included clinical parameters, radiographic outcomes (MBL) and PROMs. Results: Bleeding on probing showed an increase from BL to 1 year (34 ± 30% for Zr; 25 ± 21% for Ti). MBL remained stable with minimal changes from BL to 1 year, measuring 0.1 ± 0.4 mm (mean ± SD) for Zr and −0.1 ± 0.7 mm for Ti. Veneering fractures were the most frequent technical complication and amounted to 17.5% in group Zr and 5% in group Ti (p =.100). Patients preferred Zr implants for their soft tissue color, with a significant difference in perception between patients and clinicians (p <.017). Conclusion: The study showed that both Zr and Ti implants had similar clinical outcomes, despite a high prevalence of mucositis and a few technical complications. Both implant types demonstrated stable marginal bone levels and similar patient‐reported outcome measures. [ABSTRACT FROM AUTHOR]

Objectives: To prospectively evaluate, as part of an ongoing randomized pilot trial, the clinical outcomes of two‐piece zirconia implants in comparison with titanium implants 80 months after delivery of all‐ceramic (lithium disilicate) single‐tooth restorations. Material and methods: The original sample included 31 (16 zirconia and 15 titanium) implants in 22 healthy patients. In addition to evaluating implant survival and success, a number of clinical or radiographic parameters were statistically analyzed: plaque index (PI), bleeding on probing (BOP), pink esthetic score (PES), and marginal bone loss (MBL). Both implant groups were compared using a Mann–Whitney U test. Results: Three implants (2 zirconia and 1 titanium) had been lost, so that 28 implants (14 zirconia and 14 titanium) in 21 patients could be evaluated after a mean of 80.9 (SD: 5.5) months. All surviving implants had remained stable, in the absence of any fixture or abutment fractures and without any chipping, fracture, or debonding of crowns. The zirconia implants were associated with PI values of 11.07% (SD: 8.11) and the titanium implants with 15.20% (SD: 15.58), the respective figures for the other parameters being 16.43% (SD: 6.16) or 12.60% (SD: 7.66) for BOP; 11.11 (SD: 1.27) or 11.56 (SD: 1.01) for PES; and 1.38 mm (SD: 0.81) or 1.17 mm (SD: 0.73) for MBL. Conclusions: No significant differences were found between the clinical outcomes of two‐piece zirconia and titanium implants based on the aforementioned parameters after 80 months of clinical service. Our results should be interpreted with the limited sample size in mind. [ABSTRACT FROM AUTHOR]

Objective: To compare the contributions of implant hydrophilicity and nanotopography on anchorage in bone. The effect of elevated calcium surface chemistry on bone anchorage was also investigated. Materials and Methods: A full factorial study design was implemented to evaluate the effects of ultraviolet (UV) light and/or sodium lactate (SL) and discrete crystalline deposition of nanocrystals (DCD) treatments on the osseointegration of dual acid‐etched (AE) titanium alloy (Ti6Al4V) and grit blasted and AE (BAE) commercially pure titanium (CpTi) implants. Sodium hydroxide (NaOH)‐treated CpTi implants were immersed in simulated body fluid (SBF) to increase calcium surface chemistry. Implants were placed in the femora of Wistar rats and tested using pull‐out testing (BAE implants: 5, 9, 14 days) or tensile testing (AE implants: 9 days, NaOH implants: 28 days). Results: Ti6Al4V‐AE implants with DCD‐ and UV‐treated surfaces significantly increased bone anchorage compared with untreated Ti6Al4V‐AE alloy implants. Pull‐out testing of BAE‐CpTi implants with the DCD treatment showed increased disruption force values compared with surfaces without the DCD treatment at 5, 9 and 14 days by 4.1N, 13.9N and 15.5N, respectively, and UV‐treated implants showed an increase at 14 days by 8.4N. No difference was found between NaOH + SBF and NaOH + H2O groups. Conclusions: Bone anchorage of implants was found to be improved by UV‐treating implants or nanotopographically complex surfaces. However, implant nanotopography was found to have a greater contribution to the overall bone anchorage and is more consistent compared with the time‐dependent nature of the UV treatment. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the outcomes of excessively loaded implants. Material and Methods: In five dogs, all mandibular premolars were extracted. After 3 months, six implants (three SLA® and three SLActive®) were placed (S). After 4 weeks, implants were restored: one single crown with stable occlusal contacts (SC), one crown and a cantilever unit with excessive occlusal contacts (OL), and a non‐loaded implant (NL). Bleeding‐on‐probing (BoP), attachment level (AL), mucosal margin (GM) were assessed. Resonance frequency analysis (RFA) was assessed weekly. Standardized X‐rays were taken at S, 4 and 24 weeks. Results: Similar findings were observed for SLA® and SLActive® implants regarding PlI, GI, GM, AL, and BL. No significant differences were detected between baseline and 24‐weeks or between treatment modalities for all clinical parameters (p > .05). Six months after loading, RFA values were significantly greater than at implant placement. No significant differences between treatment modalities were found. Linear radiographic measurements yielded similar results between SLA® and SLActive® implants. SLA® OL implants yielded a statistically significant gain on peri‐implant bone density over all other groups (p = .012). Radiographic results were confirmed by descriptive histology. Technically, loosened occlusal screws occurred in 13.3% (SC = 3.3%; OL = 10%), while abutment fractures totalized 23.3% (SC = 6.6%; OL = 16.6%). Conclusions: Excessive occlusal load applied to implants (SLA® or SLActive®) restored with cantilevers did not cause loss of osseointegration or significant changes in their clinical, radiographic, or histologic outcomes. Early excessive occlusal load on SLA® implants promoted a gain in peri‐implant bone density. Excessively loaded implants showed more technical complications. [ABSTRACT FROM AUTHOR]

Objective To evaluate histologically and histomorphometrically, the peri-implant bone reaction around implants subjected to controlled progressive orthodontic loading. Materials and methods In three beagle dogs, bilateral edentulous flat alveolar ridges were created in the maxillary area posterior to the canines. After 8 weeks of healing, 24 implants (Biomet 3i) were inserted in the edentulous sites. Two experimental groups were created. Progressive loading group: Twelve implants were left to heal for 8 weeks uncovered, and abutments were adapted and connected by pairs with Ni-Ti orthodontic springs. A gradual static force of 100, 200 and 300 g was applied for a 3-week period each. Thus, a total progressive loading period of 9 weeks was exercised. Unloaded control group: Twelve implants were left to heal undisturbed. At the end of the experimental period, all implants of both groups were removed with the surrounding bone. Histologic and histomorphometric analyses were performed, and the following parameters were measured: bone-to-implant contact, bone density 1 and 2 mm distant to the implant threads and crestal bone resorption. Median regression models are used for statistical analysis. Results Implants of the progressive loading group exhibited significantly higher percentage of bone-to-implant contact compared to the unloaded control implants ( P = 0.018). Bone density 1 and 2 mm distant to the threads was found to be the same between the two groups ( P = 0.734 and P = 0.961, respectively). Crestal bone resorption did not differ between loaded and unloaded implants ( P = 0.813). Conclusion The application of progressive loading by controlled orthodontic force on osseointegrated implants provoked significant increase in the percentage of bone-to-implant contact of the low-density bone of the dog maxilla. [ABSTRACT FROM AUTHOR]

Aim: To investigate how osseointegration is affected by different nano- and microstructures. The hypothesis was that the surface structure created by dual acid treatment (AT-1), applied on a reduced topography, might achieve equivalent biomechanical performance as a rougher surface treated with hydrofluoric acid (HF). Materials and methods: In a preclinical rabbit study, three groups (I, II, and III) comprised of test and control implants were inserted in 30 rabbits. The microstructures of the test implants were either produced by blasting with coarse (I) or fine (II) titanium particles or remained turned (III). All test implants were thereafter treated with AT-1 resulting in three different test surfaces. The microstructure of the control implants was produced by blasting with coarse titanium particles thereafter treated with HF. The surface topography was characterized by interferometry. Biomechanical (removal torque) and histomorphometric (bone–implant contact; bone area) performances were measured after 4 or 12 weeks of healing. Results: Removal torque measurement demonstrated that test implants in group I had an enhanced biomechanical performance compared to that of the control despite similar surface roughness value (Sa). At 4 weeks of healing, group II test implants showed equivalent biomechanical performance to that of the control, despite a decreased Sa value. Group III test implants showed decreased biomechanical performance to that of the control. Conclusions: The results of the present study suggest that nano- and microstructure alteration by AT-1 on a blasted implant might enhance the initial biomechanical performance, while for longer healing time, the surface interlocking capacity seems to be more important. [ABSTRACT FROM AUTHOR]

Objectives The aim of the study was to evaluate if zirconia implants with micro-grooved surfaces supplemented with melatonin enhance the bone-to-implant contact ( BIC) vs. titanium implants with the same coating. Materials and methods Eighty implants divided in four groups were inserted in the tibia of 20 New Zealand rabbits as follows: (group A) 20 titanium implants; (group B) 20 micro-grooved zirconia implants; (group C) 20 titanium implants supplemented with melatonin and (group D) 20 micro-grooved zirconia implants supplemented with melatonin. Histometric and SEM evaluation of BIC were evaluated after 1 and 4 weeks. Results At 1 week, group C (29.7 ± 2.4%) and group D (28.9 ± 1.3%) implants showed higher BIC% compared with group A and B ( P < 0.05). After 4 weeks, group D showed higher BIC compared with all the groups (47.5 ± 2.2%) ( P < 0.05). Also Connective tissue was higher in groups B (78.9 ± 2.1%) and D (88.7 ± 1.2%) related to titanium and zirconia melatonin untreated at 4 weeks ( P < 0.05). Conclusions Within the limitations of this pilot study in rabbits, we can conclude that the local application of melatonin increases the BIC values in titanium and in zirconia implants at 1 week. [ABSTRACT FROM AUTHOR]

Objectives Aim of this controlled prospective randomized study was to evaluate the outcome of two-piece zirconia implants compared to titanium implants over a period of up to 24 months. Material and methods A total of 31 implants (16 zirconia/Ziterion vario Z® + 15 titanium/Ziterion vario T®) were inserted primary stable (>30 Ncm) in the maxilla (7) and mandible (24) of 22 patients (13 male, nine female) requiring neither bone nor soft tissue augmentation. After a healing period of 6 months in the maxilla and 4 months in the mandible, ceramic abutments were luted adhesively to the zirconia implants and definitive all-ceramic restoration was performed with high-density ceramics. Radiographic bone levels, condition of the peri-implant mucosa, aesthetic outcome, implant survival and success were recorded for up to 24 months. Results Measurements of mean marginal bone levels 24 months after surgery showed a significant bone loss ( P < 0.001) in both groups (Ti: 1.43 ( SD ± 0.67) vs. Zir 1.48 ( SD ± 1.05). One zirconia implant was lost 8 months after restoration. No further complications were recorded, giving an overall survival and success rate of 93.3% for zirconia and 100% for titanium implants after a period of up to 24 months. Conclusions After 24 months, success rates of the two-piece ceramic implants showed no significant difference compared to control two-piece titanium implants. The bonded zirconia implant abutment connection appears to be capable with clinical application over the observed period. However, further control measurements need to confirm the presented data. [ABSTRACT FROM AUTHOR]

Objective To investigate the influence of different surgical techniques on the primary and secondary implant stability using trabecular bone of goats as an implantation model. Material and methods In the iliac crest of eight goats, 48 cylindrical-screw-type implants with a diameter of 4.2 mm (Dyna®; Bergen op Zoom, the Netherlands) were installed, using three different surgical techniques: (i) 5% undersized, using a final drill diameter of 4 mm; (ii) 15% undersized, using a final drill diameter of 3.6 mm; and (iii) 25% undersized, using a final drill diameter of 3.2 mm. Peak insertion torque values were measured by a Digital® (MARK-10 Corporation, New York, NY, USA) torque gauge instrument during placement. At 3 weeks after implantation, removal torque was measured. Histomorphometrically, the peri-implant bone volume was measured in three zones; the inner zone (0-500 μm), the middle zone (500-1000 μm) and the outer zone (1000-1500 μm). Results Evaluation of the obtained data demonstrated no statistically significant difference between different surgical techniques regarding removal torque values. With respect to the percentage peri-implant bone volume (% BV), also no significant difference could be observed between all three applied surgical techniques for both the inner, middle and outer zone. However, irrespective of the surgical technique, it was noticed that the % BV was significantly higher for the inner zone as compared to middle and outer zone ( P < 0.05) around the implant. Conclusion At 3 weeks after implant installation, independent of the used undersized surgical technique, the % BV in the inner zone (0-500 μm) peri-implant area was improved due to both condensation of the surrounding bone as also the translocation of host bone particles along the implant surface. Surprisingly, no mechanical beneficial effect of the 25% undersized surgical technique could be observed as compared to the 5% or 15% undersized surgical technique to improve primary or secondary implant stability. [ABSTRACT FROM AUTHOR]

Objectives Although titanium is commonly used as a favorable bone implant material due to its mechanical properties, its bioactive and osteoconductive capacity is relatively low. Calcium phosphate ceramics, predominantly hydroxyapatite ( HA), have been frequently used for coating purposes to improve the bioactive properties. In view of the suggested osteopromotive capacity of bioactive glasses ( BGs), this study aimed to evaluate the effect of BG incorporation into HA coatings on implant performance in terms of bone contact and bone area. Materials and Methods A total of 48 screw-type titanium implants with magnetron sputter coatings containing different ratios of HA and BG ( HA, HABGLow, and HABGHigh; n = 8) were placed into the mandible of 16 Beagle dogs. After 4 and 12 weeks, their performance was evaluated histologically and histomorphometrically. Peri-implant bone area percentage ( BA%) was determined in three zones (inner, 0-500 μm; middle, 500-1000 μm; and outer, 1000-1500 μm). Additionally, bone-to-implant contact ( BIC%) and first bone-implant contact (1st BIC) were assessed for each sample. Results After 4 weeks, bone-to-implant contact for the HA- and HABGLow-coated groups was significantly higher ( P < 0.05) than for the HABGHigh coatings. Mean values for overall BA% showed comparable values for both the HABGLow (58.3%)- and HABGHigh (56.3%)-coated groups. Data suggest that the relative BA around the HA-coated implants (67.8%) was higher, although this was only significant compared to the HABGHigh group. After 12 weeks, all three groups showed similar bone-to-implant contact and no differences in BA were found. Conclusions The incorporation of BG into HA sputter coatings did not enhance the performance of a dental implant in implantations sites with good bone quality and quantity. On the contrary, coatings containing high concentrations of BG resulted in inferior performance during the early postimplantation healing phase. [ABSTRACT FROM AUTHOR]

Objective Simvastatin has been shown to enhance osseointegration of pure titanium implants in osteoporotic rats. This study aimed to evaluate the relationship between the serum level of bone formation markers and the osseointegration of pure titanium implants in osteoporotic rats treated with simvastatin. Materials and methods Fifty-four female Sprague-Dawley rats, aged 3 months, were randomly divided into three groups: Sham-operated group ( SHAM; n = 18), ovariectomized group ( OVX; n = 18), and ovariectomized with simvastatin treatment group ( OVX + SIM; n = 18). Fifty-six days after ovariectomy, screw-shaped titanium implants were inserted into the tibiae. Simvastatin was administered orally at 5 mg/kg each day after the placement of the implant in the OVX + SIM group. The animals were killed at either 28 or 84 days after implantation and the undecalcified tissue sections were processed for histological analysis. Total alkaline phosphatase ( ALP), bone-specific alkaline phosphatase ( BALP) and bone Gla protein ( BGP) were measured in all animal sera collected at the time of euthanasia and correlated with the histological assessment of osseointegration. Results The level of ALP in the OVX group was higher than the SHAM group at day 28, with no differences between the three groups at day 84. The level of BALP in the OVX + SIM group was significantly higher than both OVX and SHAM groups at days 28. Compared with day 28, the BALP level of all three groups showed a significant decrease at day 84. There were no significant differences in BGP levels between the three groups at day 28, but at day 84, the OVX + SIM group showed significantly higher levels than both the OVX and SHAM groups. There was a significant increase in BGP levels between days 28 and 84 in the OVX + SIM group. The serum bone marker levels correlated with the histological assessment showing reduced osseointegration in the OVX compared to the SHAM group which is subsequently reversed in the OVX + SIM group. Conclusion The results from this study indicate that the serum level of bone formation markers, especially BALP and BGP, could be correlated with the degree of osseointegration around titanium implants in osteoporotic rats treated with simvastatin. [ABSTRACT FROM AUTHOR]

Aim: To investigate bone-to-implant bonding for some novel surface modifications with a hierarchic structure and to correlate the in vivo results with surface roughness parameters. Materials and methods: Newly developed implants surfaces were tested in rabbits and compared with the commercially available OsseoSpeed™ (OS) implant. The blasted test samples were subjected to treatment in oxalic acid (AT-II), followed by subsequent etching in hydrofluoric acid (AT-I). Scanning electron microscopy and X-ray photoelectron spectroscopy were used to characterize the surface topography and chemical composition of the implants. Biomechanical testing after 6 weeks of healing was complemented with the quantification of fluorochromes and the results were subjected to a multivariate statistical analysis. Results: The results show, both with biomechanical- and with histomorphometrical tests, that the AT-I implants with different surface roughness at the micro (blasting), submicro (shallow cavities) and nanolevels (precipitates) have a greater bone tissue integration compared with the AT-II- and OS implants. The 2D bone-to-implant contact (BIC) data were in accordance with the 3D removal torque (RTQ) results even if the former were deduced from implants located in spongeous-type bone and the latter in cortical bone. The increase in RTQ values for the test samples AT-I and AT-II compared with the reference complies with the slightly higher Sa values for these surfaces. Conclusions: Using a combination of conventional methods with novel quantification of florochrome and multivariate analysis, the influence of surface roughness on different levels could be discriminated. The RTQ and BIC values show that the most hierarchical structure with submicro cavities and nanoscale precipitates possesses the most favourable osseointegration properties. To cite this article: Johansson CB, Gretzer C, Jimbo R, Mattisson I, Ahlberg E. Enhanced implant integration with hierarchically structured implants: a pilot study in rabbits Clin. Oral Impl. Res. 23, 2012; 943-953 doi: 10.1111/j.1600-0501.2011.02233.x [ABSTRACT FROM AUTHOR]

Objectives: Platelet releasate has been shown to promote osteogenetic cell proliferation and differentiation. Topography and chemistry of biomaterials have high impact on platelet activation. More specifically, the bioactive cell adhesive peptide sequence Arg-Gly-Asp (RGD) triggers platelet activation mediated by the αIIbβ3 integrin receptor. Accordingly, topographical, chemical and biomimetical (immobilized RGD peptide) modifications of titanium (Ti) surfaces may enhance early platelet activation and bony healing of implants. Therefore, the aim of the study was to evaluate platelet activation with subsequent platelet-derived cytokine release by accordingly modified Ti surfaces. Materials and methods: Pre-treated (PT; mean roughness [ Ra]=0.04 μm, contact angle [CA]=91°), acid-etched (A, Ra=0.83 μm, CA=106°), large grit-sandblasted, acid-etched (SLA, Ra=3.2 μm, CA=109°) as well as hydrophilically modified acid-etched (modA, Ra=0.83 μm, CA=0) and modified large grit-sandblasted, acid-etched (modSLA, Ra=3.2 μm; CA=0°) titanium surfaces were investigated. Additionally, RGD peptides were chemically immobilized on PT, A and SLA surfaces (PT-RGD [CA=18°], A-RGD [CA=0°], SLA-RGD [CA=0°]). The different Ti surfaces were incubated with platelet concentrate of three healthy volunteers at room temperature for 15 min and for 30 min. High thrombogenous collagen served as the control group. Out of the supernatant, platelet consumption was assessed via platelet count (PC). Cytokine release was quantified via the level of platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF). Results: After 15 min, especially the rough SLA surface showed a strong decrease in PC and a strong increase in VEGF and PDGF levels. After 30 min, high platelet consumption as well as high levels of VEGF and PDGF were measured for unspecifically modified (modA) and especially for biomimetic, specifically modified (PT-RGD, A-RGD) surfaces, indicating a delayed effect of the surface modifications on platelet activation. Discussion: Modifications of surface roughness modifications appear to influence early platelet activation and cytokine release after 15 min whereas surface chemistry modifications with increased hydrophilic properties and surface modifications via RGD peptide on plainer surfaces lead to a further, more specific promotion of platelet activation and degranulation after 30 min. The observed effect could be valuable for critical clinical situations like compromised bone sites. To cite this article: Kämmerer PW, Gabriel M, Al-Nawas B, Scholz T, Kirchmaier CM, Klein MO. Early implant healing: promotion of platelet activation and cytokine release by topographical, chemical and biomimetical titanium surface modifications in vitro. Clin. Oral Impl. Res. 23, 2012 504-510. doi: 10.1111/j.1600-0501.2011.02153.x [ABSTRACT FROM AUTHOR]

Background: Immediate/early prosthetic rehabilitation of the edentulous mandible with four or more implants for support of a fixed bridge is a well-documented procedure. Only a few studies have reported on the outcome of using three implants for this purpose. Aim: To retrospectively analyze the clinical outcome when using three implants for support of an immediately loaded fixed bridge in the totally edentulous mandible. Materials and methods: In total, 132 patients (67 females and 65 males, mean age 62.6 years, range 35-85 years) treated with 396 implants (Brånemark System) over an 11-year period in one clinic were retrospectively analyzed with regard to implant survival. Implants with both machined and oxidized surface had been used. Eighty percent of the implants were 13 mm in length or longer. The permanent bridge with acrylic teeth was delivered to the patient the same day. The patients were re-called annually for clinical examinations. Results: All patients had been followed for at least 1 year, with the longest follow-up of 10 years and a mean follow-up of 5 years. Thirteen implant failures in 10 patients were experienced, all occurring during the first 12 months of loading. The overall survival rate was 96.7% for implants and 92.4% for original bridges. More machined than oxidized implants failed, 7% vs. 1.2%. Fourteen additional implants were placed at the time of removal of the failed implants when also the fixed bridge was adjusted on the same day. Thus, all patients received and maintained a fixed bridge, except for a few hours in the 10 failure cases when the bridges were adjusted. Conclusions: This retrospective survival analysis shows that three implants can be used to support a fixed bridge for immediate loading in the edentulous mandible. The study indicated that oxidized implants were more successful than machined ones. To cite this article: Hatano N, Yamaguchi M, Yaita T, Ishibashi T, Sennerby L. New approach for immediate prosthetic rehabilitation of the edentulous mandible with three implants: a rettrospective study. Clin. Oral Impl. Res. 22, 2011; 1265-1269. doi: 10.1111/j.1600-0501.2010.02101.x [ABSTRACT FROM AUTHOR]

The purpose of the present study was to investigate the influence of different implant placement techniques on the early bone healing response in an animal model. In the present study, 24 cylindrical-screw-type implants with a diameter of 4.2 mm (Dyna) were installed, using three different surgical techniques; (1) 5% undersized, using a final drill diameter of 4 mm; (2) 15% undersized, using a final drill diameter of 3.6 mm; and (3) 25% undersized, using a final drill diameter of 3.2 mm. After 3 weeks of implantation period, the peri-implant bone response was histologically evaluated and the percentage of bone-implant contact (%BIC) calculated. New bone formation was more pronounced for implants placed with the 5% undersized or 15% undersized technique, as compared with implants installed with the 25% undersized technique. Histomorphometrical data corroborates these findings as the %BIC was significantly higher for implants inserted with the 5% undersized (47.7 ± 11.1) or 15% undersized protocol (47.5 ± 9.5) as compared with implants inserted with the 25% undersized technique (32.1 ± 9.7). No significant difference in %BIC could be observed between the 5% undersized and 15% undersized installed implants. Within the limitation of the present study, it was concluded that excessive compression of the host bone, when a discrepancy between implant and final drill diameter more than 15%, can result in an inferior tissue response in the early stage of healing. To compare research results in the future, it is advised to specify the term 'undersized' by mentioning the real reduction in diameter. Tabassum A, Meijer GJ, Walboomers XF, Jansen JA, Biological limits of the undersized surgical technique: a study in goats. Clin. Oral Impl. Res. , 2011; 129-134. doi: 10.1111/j.1600-0501.2010.02016.x [ABSTRACT FROM AUTHOR]

Objectives: The aims of this research were to evaluate the efficacy of a bioactive glass–ceramic (Biosilicate®) and a bioactive glass (Biogran®) placed in dental sockets in the maintenance of alveolar ridge and in the osseointegration of Ti implants. Material and methods: Six dogs had their low premolars extracted and the sockets were implanted with Biosilicate®, Biogran® particles, or left untreated. After the extractions, measurements of width and height on the alveolar ridge were taken. After 12 weeks a new surgery was performed to take the final ridge measurements and to insert bilaterally three Ti implants in biomaterial-implanted and control sites. Eight weeks post-Ti implant placement block biopsies were processed for histological and histomorphometric analysis. The percentages of bone–implant contact (BIC), of mineralized bone area between threads (BABT), and of mineralized bone area within the mirror area (BAMA) were determined. Results: The presence of Biosilicate® or Biogran® particles preserved alveolar ridge height without affecting its width. No significant differences in terms of BIC, BAMA, and BABT values were detected among Biosilicate®, Biogran®, and the non-implanted group. Conclusions: The results of the present study indicate that filling of sockets with either Biosilicate® or Biogran® particles preserves alveolar bone ridge height and allows osseointegration of Ti implants. To cite this article: Roriz VM, Rosa AL, Peitl O, Zanotto ED, Panzeri H, de Oliveira PT. Efficacy of a bioactive glass–ceramic (Biosilicate®) in the maintenance of alveolar ridges and in osseointegration of titanium implants. Clin. Oral Impl. Res. 21, 2010; 148–155. doi: 10.1111/j.1600-0501.2009.01812.x [ABSTRACT FROM AUTHOR]

Aim: To analyse possible effects of titanium surface topography on bone integration. Materials and methods: Our analyses were centred on a PubMed search that identified 1184 publications of assumed relevance; of those, 1064 had to be disregarded because they did not accurately present in vivo data on bone response to surface topography. The remaining 120 papers were read and analysed, after removal of an additional 20 papers that mainly dealt with CaP-coated and Zr implants; 100 papers remained and formed the basis for this paper. The bone response to differently configurated surfaces was mainly evaluated by histomorphometry (bone-to-implant contact), removal torque and pushout/pullout tests. Results and discussion: A huge number of the experimental investigations have demonstrated that the bone response was influenced by the implant surface topography; smooth ( Sa<0.5 μm) and minimally rough ( Sa 0.5–1 μm) surfaces showed less strong bone responses than rougher surfaces. Moderately rough ( Sa>1–2 μm) surfaces showed stronger bone responses than rough ( Sa>2 μm) in some studies. One limitation was that it was difficult to compare many studies because of the varying quality of surface evaluations; a surface termed ‘rough’ in one study was not uncommonly referred to as ‘smooth’ in another; many investigators falsely assumed that surface preparation per se identified the roughness of the implant; and many other studies used only qualitative techniques such as SEM. Furthermore, filtering techniques differed or only height parameters ( Sa, Ra) were reported. Conclusions: • Surface topography influences bone response at the micrometre level. • Some indications exist that surface topography influences bone response at the nanometre level. • The majority of published papers present an inadequate surface characterization. • Measurement and evaluation techniques need to be standardized. • Not only height descriptive parameters but also spatial and hybrid ones should be used. [ABSTRACT FROM AUTHOR]

Objectives: Osteoporosis is known to impair the process of implant osseointegration. The recent discovery that statins (HMG-CoA reductase inhibitors) act as bone anabolic agents suggests that statins can be used as potential agents in the treatment of osteoporosis. Therefore, we hypothesized that statins will promote osteogenesis around titanium implants in subjects with osteoporosis. Material and methods: Fifty-four female Sprague Dawley rats, aged 3 months old, were randomly divided into three groups: Sham-operated group (SHAM; n=18), ovariectomized group (OVX; n=18), and ovariectomized with Simvastatin treatment group (OVX+SIM; n=18). Fifty-six days after being ovariectomized (OVX), screw-shaped titanium implants were inserted into the tibiae. Simvastatin was administered orally at 5 mg/kg each day after the placement of the implant in the OVX+SIM group. The animals were sacrificed at either 28 or 84 days after implantation and the undecalcified tissue sections were obtained. Bone-to-implant contact (BIC) and bone area (BA) within the limits of implant threads were measured around the cortical (zone A) and cancellous (zone B) bone regions. Furthermore, bone density (BD) of zone B in a 500 μm wide zone lateral to the implants was also measured. Results: There were no significant differences in BIC and BA measurements in zone A in any of the three groups at either 28 or 84 days after implantation ( P>0.05). By contrast, in zone B, significant differences in the measurement of BIC, BA, and BD were observed at 28 and 84 days between all three groups. Bone healing decreased with lower BIC, BA, and BD around implant in OVX group compared with other two groups, and Simvastatin reversed the negative effect of OVX on bone healing around implants with the improvement of BIC, BA, and BD in zone B. Conclusion: Osteoporosis can significantly influence bone healing in the cancellous bone around titanium implants and Simvastatin was shown to significantly improve the osseointegration of pure titanium implants in osteoporotic rats. [ABSTRACT FROM AUTHOR]

Objectives: To compare the histological features of bone filled with Bio-Oss®, Ostim-Paste® or PerioGlas placed in defects in the rabbit tibiae by evaluating bone tissue composition and the integration of titanium implants placed in the grafted bone. Material and methods: Two cylindrical bone defects, about 4 mm in diameter and 6 mm in depth, were created in the tibiae of 10 rabbits. The defects were filled with either Bio-Oss®, PerioGlas, Ostim®-Paste or left untreated, and covered with a collagen membrane. Six weeks later, one titanium sandblasted and acid-etched (SLA) implant was inserted at the centre of each previously created defect. The animals were sacrificed after 6 weeks of healing. Results: Implants placed in bone previously grafted with Bio-Oss®, PerioGlas or Ostim®-Paste obtained a larger extent of osseointegration, although not statistically significant, than implants placed in non-grafted bone. The three grafting materials seemed to perform in a similar way concerning their contribution towards implant osseointegration. All grafting materials appeared to be osteoconductive, thus leading to the formation of bridges of mineralized bone extending from the cortical plate towards the implants surface through the graft scaffold. Conclusions: Grafting with the above-mentioned biomaterials did not add any advantage to the osseointegration of titanium SLA implants in a self-contained defect. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to evaluate the influence of homeopathic treatment with comfrey ( Shymphytum officinalis 6CH) on radiographic bone density and area around titanium implants. Material and methods: Forty-eight rats were divided into two groups of 24 animals each: a control group (C) and a test group (SO). Each animal received one titanium micro-implant placed in the tibia. The animals in Group SO were subjected to 10 drops of comfrey 6CH per day mixed into their drinking water until the day of sacrifice. Eight animals of each group were sacrificed at 7, 14 and 28 days post-surgery, respectively. Standardized digital radiographs were obtained on the day of implant installation (baseline images) and on the day of sacrifice (final images). Digital subtraction of the two corresponding images was performed to evaluate changes in bone density and the area related to change around the implant between baseline and final images. Results: Subtraction images demonstrated that a significant difference existed in mean shade of gray at 14 days post-surgery between Group SO (mean 175.3±14.4) and Group C (mean 146.2±5.2). Regarding the area in pixels corresponding to the bone gain in Group SO, the differences observed between the sacrifice periods and groups were only significant at 7 days sacrifice between Group SO (mean 171.2±21.9) and Group C (mean 64.5±60.4). Conclusion: Within the limits of this study, comfrey administration promotes an increase in radiographic bone density around titanium implants in the initial period of bone healing. [ABSTRACT FROM AUTHOR]

Aims: (i) To assess the pattern of early bacterial colonization on titanium oral implants after installation, at 12 weeks and at 12 months, (ii) to compare the microbiota at submucosal implant sites and adjacent subgingival tooth sites and (iii) to assess whether or not early colonization was predictive of 12-month colonization patterns. Material and methods: Submucosal/subgingival plaque samples from 17 titanium oral implants and adjacent teeth were analyzed by checkerboard DNA–DNA hybridization 30 min, 12 weeks and 12 months after implant installation. Results: At 12 months, none of the inserted implants had been lost or presented with signs of peri-implantitis. The distribution of sites at implants and teeth with bleeding on probing varied between 2% and 11%. Probing pocket depths ≤3 mm were found at 75% of implant sites. At 12 months, the sum of the bacterial counts of 40 species was statistically significantly higher at tooth compared with implant sites (mean difference: 34.4 × 105, 95% confidence interval −0.4 to 69.4, P<0.05). At 12 months, higher individual bacterial counts at tooth sites were found for 7/40 species compared with implant sites. Detection or lack of detection of Staphylococcus aureus at implant sites at 12 weeks resulted in the highest positive (e.g. 80%) and negative (e.g. 90%) predictive values, respectively. Between 12 weeks and 12 months, the prevalence of Tannerella forsythia increased statistically significantly at implant sites ( P<0.05). Lack of detection of Porphyromonas gingivalis at 12 weeks yielded a negative predictive value of 93.1% of this microorganism being undetectable at implant sites at 12 months. Conclusions: Within the limits of this study, the findings showed (i) a few differences in the prevalence of bacterial species between implant and adjacent tooth sites at 12 months and (ii) high positive and negative predictive values for selected bacterial species. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of the present study was to investigate the effect of local application of platelet-rich plasma (PRP) on the early healing of cortical bone around Ti implants with two different surface configurations. Material and methods: Six goats were used in this study. PRP fractions were obtained from a venous blood sample of the goats and administered immediately before implant insertion. PRP was applied via gel preparation and installation of the gel into the implant site, or via dipping of the implants in PRP fraction before insertion. A total of 36 implants (18 non-coated and 18 Ca-P-coated) were placed into the tibial cortical bone. The animals were sacrificed at 6 weeks after implantation and implants with surrounding tissue were prepared for histological examination. Histomorphometrical variables like the percentage of implant surface with direct bone–implant contact and the percentage of new and old bone adjacent to the implant were evaluated. Results: More interfacial bone-to-implant contact was observed for all the three groups of Ca-P-coated implants and the Ti/PRP liquid group. All groups revealed similar percentages of old and new bone adjacent to the implant. Conclusions: It was concluded that the additional use of PRP did not have any effect on the early cortical bone response to the Ca-P-coated implants, while PRP in a liquid form showed a tendency to increase bone apposition to roughened titanium implants. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to examine the effect of modified titanium (Ti) surfaces on the initial events of plasma proteins adsorption. Materials and methods: ‘Ti disks’ with three types of surface modifications were compared: machined, acid-etched and acid-etched and blasted. Physical and chemical characterizations of the surfaces were performed via scanning electron microscopy (SEM), atomic force microscopy (AFM) used for analysis of surface topography, characterization of the titanium oxide (TiO2) layer was carried out by X-ray photoelectron spectroscopy (XPS) and characterization of surface energy by the determination of contact angles. Evaluation of plasma proteins' adsorption to the treated Ti surfaces was performed by mass spectrometry, confocal laser scanning microscopy and XPS. Quantitative proteins' assessment was carried out by enzyme-linked immunosorbent assay. Results: SEM images revealed major differences in the topography of the examined surfaces. Acid-etched and blasted Ti surfaces were found to have higher roughness values and a thicker TiO2 layer as compared with acid-etched and machined surfaces. Moreover, acid-etched and blasted surfaces showed high surface area differentiation, pointing to a high increase in the three-dimensional (3D) surface area over the 2D surface area compared with the other surfaces. Adsorption of plasma proteins to the acid-etched and blasted Ti surfaces was both qualitatively and quantitatively more intense compared with the machined and acid-etched surfaces. This was shown for each examined protein, total proteins and by the removal degree of the protein coat. Conclusions: The preferential adsorption of plasma proteins to the acid-etched and blasted Ti surfaces may be explained by its topographical characteristics and by the increase of the 3D surface area of this modified surface. [ABSTRACT FROM AUTHOR]

Objectives: To monitor resonance frequency analysis (RFA) in relation to the jawbone characteristics and during the early phases of healing and incorporation of Straumann® dental implants with an SLA surface. Material and methods: 17 Straumann 4.1 mm implants (10 mm) and 7 Straumann 4.8 mm implants (10 mm) were installed and ISQ determined at baseline and after 1, 2, 3, 4, 5, 6, 8 and 12 weeks. Central bone cores were analyzed from the 4.1 mm implants using micro CT for bone volume density (BVD) and bone trabecular connectivity (BTC). Results: Pocket probing depths ranged from 2–4 mm and bleeding on probing from 5–20%. At baseline, BVD varied between 24% and 65% and BTC between 4.9 and 25.4 for the 4.1 mm implants. Baseline ISQ varied between 55 and 74 with a mean of 61.4. No significant correlations were found between BVD or BTC and ISQ Values. For the 4.8 mm diameter implants baseline ISQ values ranged from 57–70 with a mean of 63.3. Over the healing period ISQ values increased at 1 week and decreased after 2–3 weeks. After 4 weeks ISQ values, again increased slightly, no significant differences were noted over time. One implant (4.1 mm) lost stability at 3 weeks. Its ISQ value had dropped from 68 to 45. However the latter value was determined after the clinical diagnosis of instability. Conclusion: ISQ values of 57–70 represented homeostasis and implant stability. However no predictive value for loosing implant stability can be attributed to RFA since the decrease occurred after the fact. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the influence of cyclosporin A (CsA) administration on bone around integrated dental implants assessed by a bone quality index and by quantitative subtraction radiography. Material and methods: A total of 36 machine surface commercial implants were placed in 18 adult rabbits. After a 3-month healing period without any disturbance, the animals were randomly divided into three groups of six animals each. Group A was sacrificed at this time. CsA was injected subcutaneously in an immunosuppressive dose of 10 mg/kg/day in a test group (Group T), and a Group B served as a control, receiving only vehicle. After 3 months of cyclosporin administration, the animals of both Groups B and T were sacrificed. Radiographs were obtained at implant surgery and at the day of sacrifice with a CMOS sensor. Bone quality around the implants was compared between the groups using a bone quality index and quantitative subtraction radiography. Results: The bone analysis showed that in Group T, the bone quality changed dramatically from a dense cortical to a loose trabecular bone structure ( P<0.0001, χ2 test) while in Groups A and B there were no significant differences. Quantitative digital subtraction radiography showed significantly ( P<0.05) lower gray shade values (radiographic density) in a region of bone formation around the implants in Group T (118±12) than in Groups A (161±6) and B (186±10). Conclusion: Within the limits of this study, CsA administration has a negative effect on the quality of bone around integrated dental implant. [ABSTRACT FROM AUTHOR]

A major consideration in designing dental implants is to create a surface that provides strong attachment of the implant to bone, connective tissue and epithelium. The aim of the present study was to examine the influence of different treatments of titanium (Ti) implant surfaces on focal adhesion contact (FAC) formation in fibroblast cultures. Human gingival fibroblasts were cultured on glass sheets and polished Ti discs with different surface coatings (applied by physical vapor deposition (PVD): Ti, titanium nitride (TiN), zirconium nitride (ZrN)) or on Ti discs with different surface topographies. For characterization of all surfaces, modified estimation of surface roughness and spacing parameter was carried out using a contact stylus profilometer. Contact angle measurements were carried out to calculate surface energy. Fibroblasts were prepared for transmission electron microscopy at day 3 after seeding, and the number of FACs and the ratio FAC/cellular cross-sections was determined at a length of 300 μm in ultrathin sections. To visualize the extracellular fibronectin and vitronectin molecules and the intracellular actin and vinculin in FAC areas, immunogold labeling was performed. The results revealed a strong correlation between the number of FACs and the surface roughness. The highest number of FACs and the majority of the immunogold-labeled intra- and extracellular matrix molecules were counted on surfaces with the lowest surface roughness: glass sheets coated with either Ti, TiN or ZrN (roughness average=0.03–0.1 μm). These surfaces appear to favor cellular attachment of human gingival fibroblasts and moreover in previous studies the hard coatings have been shown to reduce bacterial adhesion. [ABSTRACT FROM AUTHOR]

Objectives: This study evaluated the influence of ovariectomy 8 weeks after implant placement on bone integrated to titanium implants. Material and methods: Thirty-eight female rats were submitted to a titanium implant at the tibiae proximal methaphysis. After a healing period of 8 weeks the animals were randomly divided into three groups: control (CTL-10 animals), sham-operated (SHAM-14 animals) and ovariectomy (OVX-14 animals). The CTL group was then sacrificed in order to confirm integration of the implant. The SHAM group was submitted to fictitious surgery and the OVX group was submitted to bilateral ovariectomy. After 12 weeks post-implant placement, the SHAM and OVX groups were sacrificed. In order to confirm the systemic osteopenia in rats, a dual-energy X-ray absorptiometry (DXA) was performed. For the evaluation of bone density, digital radiographs were taken. The grey level of the bone adjacent to implant was measured using image software and the bone density was calculated at six points on both sides of the implant. Results: Densitometry measurements of the femur confirmed systemic bone mass loss in the OVX group. Individualized bone analyses of different regions surrounding the implant showed a significantly lower radiographic bone density ( P<0.05) in the cancellous region of the OVX group (77.48±23.39 grey levels) when compared with the CTL and SHAM groups (91.61±32.10 and 102.57±32.50 grey levels, respectively). Conclusions: The present study showed a decrease of the radiographic bone density in the cancellous region of bone around titanium implants placed 8 weeks before ovariectomy in rats. [ABSTRACT FROM AUTHOR]

Objectives: Cyclopentenone prostaglandins have been shown to promote osteoblast differentiation in vitro. The aim of this study was to examine in a rat model the effects of local delivery of Δ12-prostaglandin J2 (Δ12-PGJ2) on new bone formation and growth factor expression in (i) cortical defects and (ii) around titanium implants. Material and methods: Standardized transcortical defects were prepared bilaterally in the femur of 28 male Wistar rats. Ten microliters of Δ12-PGJ2 at 4 concentrations (10−9, 10−7, 10−5 and 10−3 mol/l) in a collagen vehicle were delivered inside a half-cylindrical titanium chamber fixed over the defect. Contralateral defects served as vehicle controls. Ten days after surgery, the amount of new bone formation in the cortical defect area was determined by histomorphometry and expression of platelet-derived growth factor (PDGF)-A and -B, insulin-like growth factor (IGF)-I/II, bone morphogenetic protein (BMP)-2 and -6 was examined by immunohistochemistry. In an additional six rats, 24 titanium implants were inserted into the femur. Five microliters of carboxymethylcellulose alone (control) or with Δ12-PGJ2 (10−5 and 10−3 mol/l) were delivered into surgically prepared beds prior to implant installation. Results: Δ12-PGJ2 (10−5 and 10−3 mol/l) significantly enhanced new bone formation (33%, P<0.05) compared with control cortical defects. Delivery of Δ12-PGJ2 at 10−3 mol/l significantly increased PDGF-A and -B and BMP-2 and -6 protein expression ( P<0.05) compared with control defects. No significant difference was found in IGF-I/II expression compared with controls. Administration of Δ12-PGJ2 also significantly increased endosteal new bone formation around implants compared with controls. Conclusion: Local delivery of Δ12-PGJ2 promoted new bone formation in the cortical defect area and around titanium implants. Enhanced expression of BMP-2 and -6 as well as PDGF-A and -B may be involved in Δ12-PGJ2-induced new bone formation. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the effect of excessive occlusal load following placement of titanium implants in the presence of healthy peri-implant mucosal tissues. Mandibular bilateral recipient sites in six Labrador dogs were established by extracting premolars and molars. After 3 months, two TPS (titanium plasma sprayed) implants and two SLA (sandblasted, large grit, acid etched) implants were placed on each side of the mandible in each dog. Three implants were lost in the initial healing phase, leaving 45 implants for evaluation. Following 6 months of healing, gold crowns were placed on implants on the test side of the mandible. The crowns were in supra-occlusal contact with the opposing teeth in order to create excessive occlusal load. Implants on the control side were not loaded. Plaque control was performed throughout the experimental period. Clinical measurements and standardised radiographs were obtained at baseline and 1, 3 and 8 months after loading. At 8 months, the dogs were killed and histologic analyses were performed. At 8 months, all implants were osseointegrated. The mean probing depth was 2.5±0.3 and 2.6±0.3 mm at unloaded and loaded implants, respectively. Radiographically, the mean distance from the implant shoulder to the marginal bone level was 3.6±0.4 mm in the control group and 3.7±0.2 mm in the test group. Control and test groups were compared using paired non-parametric analyses. There were no statistically significant changes for any of the parameters from baseline to 8 months in the loaded and unloaded implants. Histologic evaluation showed a mean mineralised bone-to-implant contact of 73% in the control implants and 74% in the test implants, with no statistically significant difference between test and control implants. In the presence of peri-implant mucosal health, a period of 8 months of excessive occlusal load on titanium implants did not result in loss of osseointegration or marginal bone loss when compared with non-loaded implants. To cite this article: Heitz-Mayfield LJ, Schmid B, Weigel C, Gerber S, Bosshardt DD, Jönsson J, Lang NP. Does excessive occlusal load affect osseointegration? An experimental study in the dog. Clin. Oral Impl. Res. doi: 10.1111/j.1600-0501.2004.01019.x [ABSTRACT FROM AUTHOR]

This experimental pilot study was undertaken to evaluate healing of titanium implants transplanted with the surrounding bone into recipient osseous sites in the rabbit mandible. One short implant was inserted in the horizontal portion of the mandible in each of 10 New Zealand rabbits. Subsequently, and during the same session, the implant with 1.5–2.0 mm of bone circumferentially was removed using a trephine bur and immediately transplanted in a through-and-through hole prepared in the contralateral aspect of the mandible. Three months following the transplantation, the animals were sacrificed and the mandibles processed for histological evaluation. The healing pattern was assessed in relation to (1) bone bridging at the interface between the bone core and the surrounding recipient osseous tissue, (2) differences in bone density between the transplanted bone cylinder and the bone at the margins of the recipient site, and (3) bone-to-implant contact (BIC) at the interface. The transplanted graft–implant cores were integrated within the recipient sites in five out of the 10 specimens while the remaining five bone–implant cores showed fibrous encapsulation. Various patterns of resorption were observed within the peri-implant transplanted hard tissues. Percentage BIC ranged between 1% and 72% in the fibrous-encapsulated specimens and between 20% and 62% in the integrated transplants. Within the limits of this pilot study, the results suggest that immediate transplantation of endosseous implants with their surrounding bone into congruous recipient osseous sites cannot predictably yield graft-implant incorporation and osseointegration of the implants. This alternative surgical modality of immediately transplanting a composite bone graft-implant from highly cortical intraoral or extraoral sites to enhance bone quality and/or volume in implant recipient sites such as the maxillary sinus and tuberosity areas needs to be further investigated. To cite this article: Cordioli GP, Atiyeh F, Piattelli A, Majzoub Z. Healing of transplanted composite bone grafts–implants: a pilot animal study. Clin. Oral Impl. Res. 14, 2003; 750–758 [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the cell characteristics that regulate implant osseointegration. The heterogeneity of bone marrow stromal cells obtained from 11 donors was assessed by measuring the expression of a large panel of adhesion molecules. Large differences in expression of adhesion molecules were detected depending on the culture conditions used. Cells cultured in fetal bovine serum induced the expression of different adhesion molecules from cells cultured in human serum. Donor-to-donor variation was determined by measuring the expression of adhesion molecules for stromal cells obtained from different donors that were processed identically. Fat adherent cells but also loose bone marrow cells showed large differences in expression of some but not all adhesion molecules. The flow cytometric data demonstrated large heterogeneity in expression of adhesion molecules, and this heterogeneity was influenced by culture conditions and varied from donor to donor. This demonstrates that the implant encounters different cell types, which could lead to different levels of integration. Surprisingly, in vitro only a subfraction of bone marrow stromal cells attached to titanium coated with ceramic hydroxyapatite. Adaptation of all cell types present in heterogeneous bone marrow to a coated surface is apparently not possible. Differential binding was not caused by aberrant staining of the stromal cells as the results were confirmed with bone marrow cells obtained from transgenic GFP mice. These results demonstrate that hydroxyapatite ceramics are selective in cell recruitment from the bone marrow, explaining the differences found in vivo for these coatings compared with titanium. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the effect of a local single injection of amino-terminally truncated recombinant human fibroblast growth factor-4 (rhFGF-4s) on titanium implant incorporation in a rabbit bone. Material and methods: Thirty-six threaded titanium implants were inserted into the femur and tibia of six rabbits. Three weeks prior to implant insertion 10 μg of FGF-4 in an altelocollagen carrier or the carrier alone was injected into the intended implant sites. Biomechanical evaluation by (i) resonance frequency analysis and (ii) peak removal torque measurements was performed after 6 weeks. The implants with surrounding tissue were processed to undecalcified ground sections followed by light-microscopic quantifications of the bone in threaded area and the apical parts of the implants. Results: A general trend, however not statistically significant, with higher mean values obtained in the above-mentioned tests was found. The FGF-4-treated implants revealed a significantly increased bone area in the apical part of the implants compared to the corresponding control implants. Conclusion: A local single injection of rhFGF-4 may stimulate bone formation around titanium implants in bone. However, further research is required to confirm these results, understand the mechanisms of FGF, and establish optimal dose and delivery methods. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this retrospective study was to analyse bone level alterations over a 5-year period at implants in the maxillary posterior segments in patients with varying experience of periodontal bone loss in the natural dentition before implant placement. Material and methods: 97 partially dentate patients with a total of 346 Brånemark® oral implants in the maxillary posterior segments were included. By assessing the degree of radiographic marginal bone loss in the remaining natural dentition at time of the implant therapy, an age-related bone loss score (ArB-score) was calculated for description of the patient's experience of periodontal destruction. The two end quartiles of the distribution of the subjects with regard to the ArB-score were defined as Non-Perio subjects and Perio subjects, respectively. The primary outcome variables were implant losses (implant failures) and radiographic peri-implant bone loss over the 5-year observation period. Results: A total of 18 implants were lost during the 5 years, resulting in an overall failure rate of 5.2%. The corresponding failure rate was 3.3% for the Non-Perio and 8.0% for the Perio patients. The peri-implant bone loss from the time of abutment connection to 5 years averaged 1.8 mm (SD 0.7). Of the patients, 34% showed a mean bone loss of > 2 mm and 39% of all implants had experienced a bone loss of 2 mm at the 5-year examination. The Non-Perio and Perio patients showed a mean bone loss of 1.7 mm (0.8) and 2.2 mm (0.8), respectively. Multiple regression analysis revealed a statistically significant relationship between the ArB-score and the peri-implant bone level change from abutment connection to 5 years (P < 0.05). In all, 64% of Perio patients had a mean peri-implant bone loss of > 2 mm from the time of abutment connection, compared to 24% for the Non-Perio patients (P < 0.01). The percentage of implants showing 2 mm of bone loss between abutment connection and 5... [ABSTRACT FROM AUTHOR]

The present experimental study was designed to address two issues. The first was to investigate whether oxide properties of titanium implants influenced bone tissue responses after an in vivo implantation time of six weeks. If such a result was found, the second aim was to investigate which oxide properties are involved in such bone tissue responses. Screw-shaped implants with a wide range of oxide properties were prepared by electrochemical oxidation methods, where the oxide thickness varied in the range of 200 nm to 1000 nm. The surface morphology was prepared in two substantially different ways, i.e. barrier and porous oxide film structures. The micropore structure revealed pore sizes of 8 μm in diameter, with a range in opening area from 1.27 μm2 to 2.1 μm2 . Porosity ranged from 12.7% to 24.4%. The crystal structures of the titanium oxide were amorphous, anatase and a mixture of anatase and rutile type. The chemical compositions consisted mainly of TiO2 . Surface roughness ranged from 0.96 μm to 1.03 μm (Sa). Each group of test samples showed its own, defined status with respect to these various parameters. The oxide properties of turned commercially pure titanium implants were used in the control group, which was characterized by an oxide thickness of 17.4 ± 6.2 nm, amorphous type in crystallinity, TiO2 in chemical composition, and a surface roughness of 0.83 μm (Sa). Bone tissue responses were evaluated by resonance frequency measurements and removal torque tests that were undertaken six weeks after implant insertion in rabbit tibia. Implants that had an oxide thickness of approximately 600, 800 and 1000 nm demonstrated significantly stronger bone responses in the evaluation of removal torque values than did implants that had an oxide thickness of approximately 17 and 200 nm (P < 0.05). However, there were no difference between implants with oxide thicknesses of 17 and 200 nm... [ABSTRACT FROM AUTHOR]

Treatment of severe maxillary atrophy despite complex major surgery often ends up with an unsatisfactory result. This paper presents the augmentation of the maxilla with a prefabricated free vascularized fibula flap in combination with ITI® implants (Straumann AG, Waldenburg, Switzerland) in 4 patients. The technique of prefabrication for the reconstruction of maxillofacial defects is described based on the experience with 17 patients. The key points of this treatment are i) preoperative planning and fabrication of the drilling template; ii) prefabrication of the fibula with ITI® implants and performing of a “vestibuloplasty” using a skin graft; iii) technical construction and fabrication of the suprastructure and the denture; iv) reconstruction of the maxilla using the prefabricated fibula as free vascularized flap. The reconstructions with the fibula flaps were successful and the 18 ITI® implants that have been inserted showed good osseointegration without loss of attachment in all 4 patients after a mean observation period of 12 months. [ABSTRACT FROM AUTHOR]

Abstract: Gingival esthetics around natural teeth is based upon a constant vertical dimension of healthy periodontal soft tissues, the Biologic Width. When placing endosseous implants, however, several factors influence periimplant soft and crestal hard tissue reactions, which are not well understood as of today. Therefore, the purpose of this study was to histometrically examine periimplant soft tissue dimensions dependent on varying locations of a rough/smooth implant border in one‐piece implants or a microgap (interface) in two‐piece implants in relation to the crest of the bone, with two‐piece implants being placed according to either a submerged or a nonsubmerged technique. Thus, 59 implants were placed in edentulous mandibular areas of five foxhounds in a side‐by‐side comparison. At the time of sacrifice, six months after implant placement, the Biologic Width dimension for one‐piece implants, with the rough/smooth border located at the bone crest level, was significantly smaller (P<0.05) compared to two‐piece implants with a microgap (interface) located at or below the crest of the bone. In addition, for one‐piece implants, the tip of the gingival margin (GM) was located significantly more coronally (P<0.005) compared to two‐piece implants. These findings, as evaluated by nondecalcified histology under unloaded conditions in the canine mandible, suggest that the gingival margin (GM) is located more coronally and Biologic Width (BW) dimensions are more similar to natural teeth around one‐piece nonsubmerged implants compared to either two‐piece nonsubmerged or two‐piece submerged implants. [ABSTRACT FROM AUTHOR]

Abstract: Textured implant surfaces are thought to enhance endosseous integration. Torque removal forces have been used as a biomechanical measure of anchorage, or endosseous integration, in which the greater forces required to remove implants may be interpreted as an increase in the strength of bony integration. The purpose of this study was to compare the torque resistance to removal of screw-shaped titanium implants having a dual acid-etched surface (Osseotite®) with implants having either a machined surface, or a titanium plasma spray surface that exhibited a significantly more complex surface topography. Three custom screw-shaped implant types – machined, dual acid-etched (DAE), and titanium plasma sprayed (TPS) – were used in this study. Each implant surface was characterized by scanning electron microscopy and optical profilometry. One DAE implant was placed into each distal femur of eighteen adult New Zealand White rabbits along with one of the other implant types. Thus, each rabbit received two DAE implants and one each of the machined, or TPS, implants. All implants measured 3.25 mm in diameter × 4.00 mm in length without holes, grooves or slots to resist rotation. Eighteen rabbits were used for reverse torque measurements. Groups of six rabbits were sacrificed following one, two and three month healing periods. Implants were removed by reverse torque rotation with a digital torque-measuring device. Three implants with the machined surface preparation failed to achieve endosseous integration. All other implants were anchored by bone. Mean torque values for machined, DAE and TPS implants at one, two and three months were 6.00±0.64 N-cm, 9.07±0.67 N-cm and 6.73±0.95 N-cm; 21.86±1.37 N-cm, 27.63±3.41 N-cm and 27.40±3.89 N-cm; and 27.48±1.61 N-cm, 44.28±4.53 N-cm and 59.23±3.88 N-cm, respectively. Clearly, at the earliest time point the stability of DAE implants was comparable to that of TPS implants, while that of the machined implants was an order of magnitude lower. The TPS implants increased resistance to reverse torque removal over the three-month period. The results of this study confirm our previous results that demonstrated enhanced bony anchorage to dual acid-etched implants as compared to machined implants. Furthermore, the present results indicate that dual acid etching of titanium enhances early endosseous integration to a level which is comparable to that achieved by the topographically more complex TPS surfaces. [ABSTRACT FROM AUTHOR]

Abstract: This clinical study was undertaken to: 1) evaluate the use of bioactive glass BiogranTM combined with autogenous bone as grafting material for maxillary sinus augmentation with simultaneous implant placement using radiography and histology; and 2) document the short-term post-loading success of implants inserted in sinus cavities augmented with this material. Unilateral or bilateral sinus augmentation was performed in 12 patients with 3–5 mm of alveolar crestal bone height in the posterior maxilla prior to grafting. The sinuses were grafted with bioactive glass mixed in a 4:1 ratio with autogenous bone. Simultaneously, 2–3 threaded titanium implants were inserted into the augmented sinuses. Second stage surgery was carried out 9 to 12 months post implantation. At abutment connection, 10 core biopsy specimens were taken from different grafted sites and evaluated histologically. All 27 implants were clinically stable at second stage surgery. A mean increase in mineralized tissue height of 7.1±1.6 mm was evident when comparing the pre-surgical CT scans with those performed 9–12 months following the sinus augmentation procedure. Evaluation of the cores yielded a mean of 30.6±5.7% of bone tissue in the grafted sites. One implant failed during the prosthetic phase while the remaining 26 implants were stable 12 months post loading. This study suggests that BiogranTM/autogenous bone graft combination used in one-stage sinus augmentation yields sufficient quality and volume of mineralized tissue for predictable simultaneous implant placement in patients with 3–5 mm of bone height prior to grafting. [ABSTRACT FROM AUTHOR]

Abstract: Twenty-seven patients received 2 microimplants each during implant surgery. One microimplant was blasted with 25 μm sized particles of TiO2; the other was left as machined i.e. a turned surface. Before insertion the surface topography was characterized with an optical confocal laser profilometer. The surface roughness was greater than standard implants, and was similar for both surface modifications averaging over all parts of the implant i.e. tops, valley and flanks. The mean surface roughness from flank measurements only replicated previously reported findings: i.e. significantly rougher surfaces on blasted implants. After a mean healing period of 6.3 months in the maxillae and 3.9 months in the mandible, the microimplants and surrounding tissue were removed with a trephine burr. The histomorphometrical evaluation demonstrated significantly higher bone-to-implant contact for the blasted implants, inserted in the maxilla or in the mandible. Significantly more bone was found inside the threaded area for the blasted implants in the mandible, but there was no difference for implants positioned in maxillae. [ABSTRACT FROM AUTHOR]

Abstract: The aim of the study was to evaluate the effect of lateral static load induced by an expansion force on the bone/implant interface and adjacent peri-implant bone. In 3 beagle dogs, the 2nd, 3rd and 4th mandibular premolars were extracted bilaterally. Twelve weeks later 8 implants of the ITI Dental Implant System were placed in each dog. Crowns connected in pairs were screwed on the implants 12 weeks after implant installation. The connected crowns contained an orthodontic expansion screw yielding 4 loading units in each dog. Clinical registrations, standardized radiographs and fluorochrome labeling were carried out during the 24-week loading period. Biopsies were harvested and processed for ground sectioning. The sections were subjected to histological examination. No evident marginal bone loss was observed at either test or control sites. The bone density and the mineralized bone-to-implant contact were higher adjacent to the lateral loaded implants than at the unactivated control sites. It is suggested that the static load applied to implants in a lateral direction resulted in a structural adaptation of the peri-implant bone. [ABSTRACT FROM AUTHOR]

Abstract: A new X-ray microtomographic technique for non-invasive assessment of the structure of bone surrounding implants was tested. Three titanium microimplants retrieved directly (n=2) or 6 months (n=1) after insertion in 3 patients were used as test samples. Two samples were used dry and one was embedded in plastic resin prior to microtomography. The technique provided high-resolution consecutive cross-sectional X-ray images of the specimens with a slice-to-slice distance of 4.4 to 11.0 μm. The pictures could be imported into an image analysing software with which semiautomatic quantitative measurement of the bone area and three-dimensional images of the specimens could be made. It is suggested that the technique may be used for non-invasive assessment of the bone structure around implants. Further studies are needed to evaluate the accuracy of the technique, for instance by comparing tomographic sections with histologic ones. [ABSTRACT FROM AUTHOR]

Research in implant dentistry has mainly focused on hard tissue integration with much less data available with regards to soft tissue integration involving epithelium and connective tissue. In the present study, the implantogingival junction of unloaded and loaded non-submerged titanium implants has been analyzed histometrically in the canine mandible. In 6 foxhounds, 69 implants were placed. Dogs in the unloaded group were sacrificed 3 months after implant placement. Loaded implants were restored with gold crowns and those dogs were sacrificed after 3 months and 12 months of loading. Non-decalcified histologic sections were analyzed histometrically measuring the dimensions of the Sulcus Depth (SD), the Junctional Epithelium (JE), and the Connective Tissue Contact (CTC). Histometric evaluation revealed that significant changes within tissue compartments (SD, JE, CTC) occurred over time (P<0.05). Sulcus Depth had a mean of 0.49 mm and 0.50 mm after 3 months and 6 months of healing, but after 15 months was 0.16 mm which was significantly different. Similarly, the length of the Junctional Epithelium after 3 months and 6 months of healing was 1.16 mm and 1.44 mm, respectively, and these values were significantly different from measurements taken after 15 months (1.88 mm). The area of Connective Tissue Contact showed a different pattern of change in that after 3 months of healing (1.36 mm) it was significantly different from the same area after 6 months and 15 months which were 1.01 mm and 1.05 mm, respectively. Interestingly, the sum of SD, JE, and CTC, forming the Biologic Width, did not change over the observation period (P>0.05). These data indicate that the Biologic Width is a physiologically formed and stable structure over time in the case of non-submerged, one-piece titanium implants as evaluated histometrically under unloaded and loaded conditions. Dynamic changes did occur, however, within the overall Biologic Width dimension. Thus, the use of non-submerged, one-piece implants allow for stable overall peri-implant soft tissues as evaluated under loaded conditions for up to 12 months. [ABSTRACT FROM AUTHOR]

The objective of the present report was to study the effects of barrier membranes on bone resorption and implant stability in a rabbit onlay bone graft model, using resonance frequency analysis, coordinate measurements on plaster models, removal torque measurements and histology. Disc-shaped bone grafts were harvested from the calvarium and placed with titanium implants in the proximal tibial metaphyses of 9 rabbits. On one side (test) the bone graft/implant was covered by an e-PTFE barrier, while the contralateral side was not covered by a membrane and served as control. Three animals were sacrificed after 8 weeks for histology. In 6 animals the membranes were removed after 8 weeks and the animals were followed for an additional period of 16 weeks. Implant stability and bone height around the implants was assessed for the test and control sides at Day 0 and 8, 16 and 24 weeks postoperatively. Removal torque tests were performed after 24 weeks. The results showed an increase in volume of the bone graft on the test side as long as the barrier membrane was in place. However, after removal of the membrane at 8 weeks the resorption rate was higher on the test side compared to the control side, resulting in a similar bone height after 24 weeks. There were no statistically significant differences in implant stability between the test and control sides at any time point, as measured with resonance frequency analysis. Additionally, no statistically significant differences were found between the test and control sides after 24 weeks, using removal torque measurements, coordinate measurements and histomorphometric evaluation. Thus, in this experimental model, the use of non-resorbable barrier membranes did not improve the stability of implants simultaneously placed with onlay bone grafts. Moreover, extensive resorption of the grafted bone was seen after barrier removal, which resulted in similar bone graft volume for the test and control sides at the end of the... [ABSTRACT FROM AUTHOR]

In a randomized controlled clinical trial carried out at the Ignatius teaching hospital in Breda, The Netherlands, I10 edentulous patients with severe mandibular bone loss were treated with implants of the ITI® Dental Implant System using 3 different treatment strategies: a mandibular overdenture supported by either 2 implants with ball attachments, 2 implants with an interconliecting bar, or by 4 interconnected implants. In this study, results of clinical and radiographic parameters were evaluated and compared over a period of 19 months after implant placement. A total of 283 ITP Dental Implants were placed. Six implants (2%) were lost during the osseointegration period. No further implant losses occurred after that, At the 19 month evaluation mean values and standard deviations for bleeding index were 0.51±0.5 (bleeding incidence=70%) and for plaque index they were 0.46±0.5 (plaque incidence=45%). The mean values and standard deviations for probing depth and loss of attachment were 2.7±1.1 mm and 0.26±O.6 mm respectively. The radiographic evaluation showed a mean bone loss of 1.5 mm± 0.26 after 19 months for all the implants. In cases with 4 interconnected implants there was significantly more bone loss around the central 2 implants (2.1±0.31 mm) in comparison with the lateral 2 (1.4±0.25 mm). No significant correlations were found between plaque and bleeding indices and bone loss. [ABSTRACT FROM AUTHOR]

The purpose of the present in vitro investigation was to measure temperature changes at the implant surface when using pulsed CO2 laser in a simulated implant surface decontamination protocol. Six threaded titanium implants were placed in a fresh resected pig mandible. A 4x4 mm defect was created buccally to each implant in order to expose the implant head and approximately 5 threads. Temperature changes were monitored by two thermocouples placed near the dehiscence and at the apical part of the implant. Several setting combinations of the CO2 laser with regard to output power, pulse width, pulse repetition rate and irradiation time were tested on dry and wet (distilled water) surfaces. Only minor temperature increases were measured when lasing wet titanium surfaces, while the temperature at dry surfaces exceeded the proposed thresholds for bone damage at clinically relevant settings. It is concluded that the CO2 laser when used on a wet implant surface in a pulsed mode at 8 W/l0 ms/ 20 hz during 5 s induces a temperature increase of less than 3oC. This would minimize the risk of temperature induced tissue damage as a result of lasing implant surfaces. [ABSTRACT FROM AUTHOR]

In order to ensure an adequate space where new bone can be formed in guided bone regeneration (GBR), most surgeons fill bone defects with biomaterials. In this work we evaluated new bone regeneration in 10 patients using only a blood clot protected with titanium grids and non-resorbable membranes, without any filling material. A manual measurement of the size of the bone defect, using a plastic probe, was performed at 2 surgical steps. After 5 months of treatment, a biopsy was taken from each patient, fixed and embedded in PMMA, examined microradiographically and morphologically to evaluate the newly-formed bone. Our results showed a good repair of the defects by bone regeneration (about 85% overall), high mineral density of new bone around the implants after 5 months, and steady state deposition processes. These results in GBR, without filling material, apear very promising for implantology and reconstructive odontostomatology practice. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to analyse clinically failed and retrieved implants prior to and after cleaning by means of scanning electron microscopy (SEM) and X-ray induced photoelectron spectroscopy (XPS) as compared to unused controls. Six different chemical and physical techniques for cleaning of contaminated titanium implants were evaluated: 1) rinsing in absolute ethanol for 10 min, 2) cleaning in ultrasonic baths containing trichloroethylene (TRI) and absolute ethanol, 10 min in each solution, 3) abrasive cleaning for 30 s, 4) cleaning in supersaturated citric acid for 30 s, 5) cleaning with continuous CO2 laser in dry conditions at 5 W for 10 s, 6) cleaning with continuous CO2 laser in wet conditions (saline) at 5 W for 10 s. SEM of failed implants showed the presence of contaminants of varying sizes and XPS showed almost no titanium but high carbon signals. XPS of unused titanium implants showed lower levels of titanium as previously reported, probably due to contamination of carbon which increased with time in room air. Cleaning of used implants in citric acid followed by rinsing with deionized water for 5 min followed by cleaning in ultrasonic baths with TRI and absolute ethanol gave the best results with regard to macroscopical appearance and surface composition. However, as compared to the unused implants the results from an element composition point of view were still unsatisfactory. It is concluded that further development and testing of techniques for cleaning of organically contaminated titanium is needed. [ABSTRACT FROM AUTHOR]

Objectives The aim of this consensus meeting was to assess the impact of implant-abutment connection, positioning of the machined collar/microgap, and platform switching on crestal bone level changes. Materials and methods Two comprehensive systematic reviews were prepared in advance of the meeting. Consensus statements, practical recommendations, and implications for future research were based on within group as well as plenary scrutinization and discussions of these systematic reviews. Results Placing the smooth part of the implant below the alveolar crest may lead to bone loss. Despite a more pronounced bone remodeling, the subcrestal positioning of the microgap may help to retain the bony coverage of the rough surface. Crestal bone remodeling has been observed for either internal and external, or conical and butt-joint connections. There was a trend favoring the platform switching concept to prevent or minimize peri-implant marginal bone loss. Conclusions Future research should consider an uniform and comparable study design, either excluding or exactly documenting possible confounding factors. [ABSTRACT FROM AUTHOR]