A pilot study to evaluate the success and survival rate of titanium-zirconium implants in partially edentulous patients: results after 24 months of follow-up

Objectives: 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. Methods: 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. Results: 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. Conclusions: 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. To cite this article:
Barter S, Stone P, Brägger U. A pilot study to evaluate the success and survival rate of titanium–zirconium implants in partially edentulous patients: results after 24 months of follow‐up.
Clin. Oral Impl. Res. 23 , 2012; 873–881.
doi: 10.1111/j.1600‐0501.2011.02231.x     

Tissue integration of a new titanium-zirconium dental implant: a comparative histologic and radiographic study in the canine

Background: This study evaluates a newly developed titanium–zirconium implant (TiZr), comparing it to a commercially available pure titanium (Ti) implant subjected to the same surface treatment. Methods: In nine dogs, 12 implants (six TiZr and six Ti) were randomly placed in the mandible with the implant shoulder at the bone crest and subjected to submerged healing. Standardized radiographs were taken after implantation, and at the sacrifice of 2 weeks (three dogs), 4 weeks (three dogs), and 8 weeks (three dogs). Histologic and histomorphometric measurements were performed on non‐decalcified histologic sections. The main outcome measures included the first bone–implant contact (fBIC) and BIC over time. For statistical analysis, Wilcoxon signed‐rank test and mixed model regressions were applied. Results: From baseline to 8 weeks, a mean bone loss of 0.09 ± 0.33 mm for TiZr and a gain of 0.02 ± 0.33 mm for Ti were calculated radiographically. The number of implants with the fBIC coronal to the reference point (implant shoulder) gradually increased over time, reaching 39% of all TiZr implants and 50% of all Ti implants at 8 weeks. The mean fBIC values for Ti and TiZr were 0.29 ± 0.42 mm and 0.26 ± 0.32 mm (2 weeks), ?0.01 ± 0.20 mm and 0.10 ± 0.28 mm (4 weeks), and ?0.06 ± 0.22 mm and 0.08 ± 0.30 mm (8 weeks), respectively. The mean BIC values peaked at 86.9% ± 6.8% (8 weeks) for TiZr and at 83.4% ± 5.9% (4 weeks) for Ti. No statistically significant differences were observed at any time point. Conclusion: TiZr and Ti bone level implants with chemically‐modified, sandblasted, and acid‐etched surfaces performed similarly in regards to osseointegration in this unloaded canine study.     

Evaluation of a New Titanium‐Zirconium Dental Implant: A Biomechanical and Histological Comparative Study in the Mini Pig

Background: Titanium zirconium alloy with 13–17% zirconium (TiZr1317) shows significantly better mechanical attributes than pure Ti with respect to elongation and fatigue strength. This material may be suitable for thin implants and implant components exposed to high mechanical constraints. Purpose: The aim of this study was to test the hypothesis that TiZr1317 and Ti implants show comparable osseointegration and stability. Materials and Methods: The mandibular premolars (P1, P2, P3) and the first molar (M1) in 12 adult miniature pigs were extracted 3 months prior to the study. Six specially designed implants made from Ti (commercially pure, Grade 4) or TiZr1317 (Roxolid®, Institut Straumann AG, Basel, Switzerland) with a hydrophilic sandblasted and acid‐etched (SLActive, Institut Straumann AG, Basel, Switzerland) surface were placed in each mandible; three standard implants modified for evaluation of removal torque (RT) in one side and three bone‐chamber implants for histologic observations in the contralateral side. RT tests were performed after 4 weeks when also the bone chamber implants and surrounding tissue were biopsied for histologic analyses in ground sections. Results: The RT results indicated significantly higher stability (p = 0.013) for TiZr1317 (230.9 ± 22.4 Ncm) than for Ti implants (204.7 ± 24.0 Ncm). The histology showed similar osteoconductive properties for both implant types. Histomorphometric measurements showed a statistically significant higher (p = 0.023) bone area within the chamber for the TiZr1317 implants (45.5 ± 13.2%) than did the Ti implants (40.2 ± 15.2%). No difference was observed concerning the bone to implant contact between the groups with 72.3 ± 20.5% for Ti and 70.2 ± 17.3% for TiZr1317 implants. Conclusion: It is concluded that the TiZr1317 implant with a hydrophilic sandblasted and acid‐etched surface showed similar or even stronger bone tissue responses than the Ti control implant     

Three-dimensional bone response to commercially pure titanium, hydroxyapatite, and calcium-ion-mixing titanium in rabbits

Three-dimensional bone response to 3 biomaterials--commercially pure titanium (Ti), hydroxyapatite (HA), and calcium-ion-mixing titanium (Ca-Ti)--embedded in the tibiae of rabbits was examined chronologically. The rabbits were sacrificed at 2, 4, and 8 weeks after implantation, and the percent bone volume around each implant was calculated from the implant surface to each of 4 measurements: 36 microns, 0.25 mm, 0.5 mm, and 1.0 mm in 2 regions (cortical bone and bone marrow regions). Percent bone volume in the cortical bone was consistent, whereas in the bone marrow region, the percent bone volume varied according to implant material, implantation period, and distance from the implant surface. With Ti implants the percent increased gradually up to 8 weeks at each distance, whereas in HA and Ca-Ti implants the percent was largest at 4 weeks and increased closer to the surface. The percent with Ti implants was largest at 36 microns to 0.25 mm. Aspect of bone response to Ca-Ti was its position intermediate between those of HA and Ti. The decrease of the percent at 8 weeks was smaller than HA.     

A comparison of 3 different endosseous nonsubmerged implants in edentulous mandibles: a clinical report.

The purpose of this prospective clinical study was to investigate the outcome of 3 different types of endosseous, nonsubmerged implants in the anterior part of the mandible. Fourteen older edentulous patients, 10 females and 4 males, were included. All participants received 3 different types of endosseous implants in the anterior mandible: 1 titanium plasma-sprayed cylindric implant (4 mm in diameter), 1 titanium cylindric implant with hydroxyapatite (HA) coating (4 mm in diameter), and 1 standard threaded titanium implant (3.75 mm in diameter). The 3 types of implants were originally designed to be placed in a 2-step surgical procedure. However, at this stage all implants were simultaneously provided with a temporary abutment that penetrated the mucosa. Three months later the temporary abutments were replaced by ball abutments, which were connected to an overdenture. At 12, 24, and 36 months after surgery, marginal bone resorption and Periotest values were recorded. Two patients died within the 2 first postoperative years. Five of 42 implants (11.9%) failed to osseointegrate. After 3 years, marginal bone resorption around titanium plasma-sprayed implants was significantly greater than that seen around both HA-coated and threaded titanium implants. Threaded titanium implants also had significantly better scores for marginal bone resorption than the HA-coated implants. Periotest values for HA-coated cylinders were significantly lower than test values for the other implants after 3 years (P < .05). The conclusion from this investigation is that nonsubmerged implants showed impaired prognoses compared to implants placed according to the 2-stage concept. Marginal bone resorption around titanium plasma-sprayed cylindric implants was clearly increased compared to the 2 other implant systems. Periotest values for HA-coated cylindric implants were superior to titanium plasma-sprayed and pure titanium implant surfaces.     

Histomorphometric analysis of the osseointegration of four different implant surfaces in the femoral epiphyses of rabbits

Objectives: The surface properties of titanium dental implants are key parameters for rapid and intimate bone–implant contact. The osseointegration of four implant surfaces was studied in the femoral epiphyses of rabbits. Material and methods: Titanium implants were either grit‐blasted with alumina or biphasic calcium phosphate (BCP) ceramic particles, coated with a thin octacalcium phosphate (OCP) layer, or prepared by large‐grit sand blasting and acid‐etched (SLA). After 2 and 8 weeks of implantation, the bone‐implant contact and bone growth inside the chambers were compared. Scanning electron microscopy (SEM) and profilometry showed distinct microtopographies. Results: The alumina‐Ti, BCP‐Ti and OCP‐Ti groups had similar average surface roughness in the 1–2 μm range whereas the SLA surface was significantly higher with a roughness averaging 4.5 μm. Concerning the osseointegration, the study demonstrated a significantly greater bone‐to‐implant contact for both the SLA and OCP‐Ti surfaces as compared with the grit‐blasted surfaces, alumina‐ and BCP‐Ti at both 2 and 8 weeks of healing. Conclusion: In this animal model, a biomimetic calcium phosphate coating gave similar osseointegration to the SLA surface. This biomimetic coating method may enhance the apposition of bone onto titanium dental implants.     

Stability of crestal bone level at platform-switched non-submerged titanium implants: a histomorphometrical study in dogs

Objectives: To investigate the influence of platform switching on crestal bone level changes at non-submerged titanium implants over a period of 6 months.
Material and Methods: Titanium implants ( n =72) were placed at 0.4 mm above the alveolar crest in the lower jaws of 12 dogs and randomly assigned to either matching or non-matching (circumferential horizontal mismatch of 0.3 mm) healing abutments. At 4, 8, 12, and 24 weeks, dissected blocks were processed for histomorphometrical analysis. Measurements were made between the implant shoulder (IS) and the apical extension of the long junctional epithelium (aJE), the most coronal level of bone in contact with the implant (CLB), and the level of the alveolar bone crest (BC).
Results: At 24 weeks, differences in the mean IS–aJE, IS–CLB, and IS–BC values were 0.2 ± 1.2, 0.3 ± 0.7, and 0.3 ± 0.8 mm at the buccal aspect, and 0.2 ± 0.9, 0.3 ± 0.5, and 0.3 ± 0.8 mm at the lingual aspect, respectively. Comparisons between groups revealed no significant differences at either the buccal or the lingual aspects.
Conclusions: It was concluded that (i) bone remodelling was minimal in both groups and (ii) platform switching may not be of crucial importance for maintenance of the crestal bone level.     

Bone tissue responses to glass fiber-reinforced composite implants – a histomorphometric study

Objectives: The aims of this study were to evaluate bone-to-implant contact (BIC) and the osteoconductive capacity of bioactive fiber-reinforced composite implant (FRC) in vivo .
Material and methods: Threaded sand-blasted FRC implants and threaded FRC implants with bioactive glass (BAG) were fabricated for the study. Titanium implants were used as a reference. Eighteen implants (diameter 4.1 mm, length 10 mm) were implanted in the tibia of six pigs using the press-fit technique. The animals were sacrificed after 4 and 12 weeks. Histomorphometric and scanning electron microscopic (SEM) analyses were performed to characterize BIC.
Results: In general, the highest values of BIC were measured in FRC-BAG implants, followed by FRC and Ti implants. At 4 weeks, the BIC was 33% for threaded FRC-BAG, 27% for FRC and 19% for Ti. At 12 weeks, BIC was 47% for threaded FRC-BAG, 40% for FRC and 42% for Ti. Four weeks after implantation, all the implants appeared biologically fixed by a newly formed woven bone arranged in the thin bone trabeculae filling the gap between the implant and the bone of the recipient site. Twelve weeks after implantation, the thickness of the woven bone trabeculae had increased, especially around the FRC-BAG implants.
Conclusion: Our results suggest that the FRC implant is biocompatible in bone. The biological behavior of FRC was comparable to that of Ti after 4 and 12 weeks of implantation. Furthermore, the addition of BAG to the FRC implant increased peri-implant osteogenesis and bone maturation.     

One-year outcome of narrow diameter blasted implants for rehabilitation of maxillas with knife-edge resorption

Objectives: This study aimed at assessing the clinical outcome of narrow diameter implants in the treatment of knife‐edge edentulous maxillas of adequate bone height but inadequate width (class IV of Cawood and Howell). Material and methods: Twelve consecutive patients (eight women and four men, mean age 58 years) with class IV atrophic edentulous maxillas were included in the study. Seventy‐three microthreaded TiO₂‐blasted implants were placed and the resonance frequency measured. All the implants had a diameter of 3.5 mm. After 6 months of submerged healing, fixed implant‐supported prostheses were delivered to the patients and resonance frequency and radiographic examinations performed. After the first year of loading, the implant outcome was again evaluated clinically, radiographically and with resonance frequency analysis. Results: All the implants were followed up to 1 year of loading and their survival rate was 100%. Bone loss after 1 year of loading was (mean±SD) 0.30±0.13 mm. Stability values were (mean±SD) 63±5.8 ISQ at placement, 60±4.7 ISQ at the abutment connection and 61±5 ISQ after 1 year of loading. A significant difference resulted between placement and abutment connection values (P=0.03). Conclusions: According to the present study, narrow implants may be used to restore edentulous maxillas with atrophies of class IV of Cawood and Howell. When planning the treatment of edentulous maxillas with such a resorption pattern, this possibility has to be considered as an alternative to more demanding grafting techniques.     

Early laser-welded titanium frameworks supported by implants in the edentulous mandible: a 15-year comparative follow-up study

Background: Comparative long‐term knowledge of different framework materials in the edentulous implant patient is not available for 15 years of follow‐up. Purpose: To report and compare a 15‐year retrospective data on implant‐supported prostheses in the edentulous mandible provided with laser‐welded titanium frameworks (test) and gold alloy frameworks (control). Materials and Methods: Altogether, 155 patients were consecutively treated with abutment‐level prostheses with two early generations of fixed laser‐welded titanium frameworks (titanium group). Fifty‐three selected patients with gold alloy castings formed the control group. Clinical and radiographic 15‐year data were collected and compared for the groups. Results: All patients who were followed up for 15 years (n = 72) still had a fixed prosthesis in the mandible at the termination of the study. The 15‐year original prosthesis cumulative survival rate (CSR) was 89.2 and 100% for titanium and control frameworks (p = .057), respectively (overall CSR 91.7%). The overall 15‐year implant CSR was 98.7%. The average 15‐year bone loss was 0.59 mm (SD 0.56) and 0.98 mm (SD 0.64) for the test and control groups (p = .027), respectively. Few (1.3%) implants had >3.1‐mm accumulated bone loss after 15 years. The most common complications for titanium frameworks were resin or veneer fractures and soft tissue inflammation. Fractures of the titanium metal frame were observed in 15.5% of the patients. More patients had framework fractures in the earliest titanium group (Ti‐1 group) compared to the gold alloy group (p = .034). Loose and fractured implant screw components were few (2.4%). Conclusion: Predictable overall long‐term results could be maintained with the present treatment modality. Fractures of the metal frames and remade prostheses were more common in the test group, and the gold alloy frameworks had a tendency to work better when compared with welded titanium frameworks during 15 years. However, on the average, more bone loss was observed for implants supporting gold alloy frameworks.     

Titanium Mesh Technique in Rehabilitation of Totally Edentulous Atrophic Maxillae: A Retrospective Case Series

Background: This study evaluates implant‐borne prosthetic rehabilitation of 10 totally edentulous atrophic maxillae after bone reconstruction with a titanium‐mesh technique and particulate bone graft. Methods: Ten atrophic maxillae were reconstructed with 19 titanium meshes and particulate autologous‐heterologous bone. Maxillae were rehabilitated at least 5 months, with placement of 67 implants connected to the prostheses after an additional 4 months of rehabilitation. Cases were evaluated retrospectively in terms of complication rates, particularly on the amount of mesh exposure, implant survival, and success rates at the end of follow‐up. Results: In seven cases, two meshes were prematurely exposed (within 4 to 6 weeks), and five were exposed later (after 4 to 6 weeks). Only two of the later exposures extended >1 cm². Nevertheless, reconstructions allowed implant placement and prosthetic rehabilitation in all cases. Two implants were lost before loading. After mean follow‐up at 39.3 (20 to 56) months since prosthetic loading, all 65 implants were functional (100% implant survival), but 15 implants demonstrated a peri‐implant mean bone resorption of 2.96 mm increased bone loss, yielding a cumulative implant success rate of 76.9%. No prosthetic problem was observed. Conclusions: Use of titanium mesh with particulate bone can be considered a valid option in reconstructing atrophic maxillae to allow for implant‐borne prosthetic rehabilitation. A high level of dehiscence did not compromise final outcome.     

Prospective study with a 2‐year follow‐up on immediate implant loading in the edentulous mandible with a definitive restoration using intra‐oral welding

Objectives: The aim of this prospective study was to evaluate the concept of intra‐oral welding as a suitable technique for the fabrication of a restoration for edentulous mandibles on the same day as surgery using tapered connection implants. Material and methods: Each of 20 patients had an edentulous mandible and received four inter‐foraminal, tapered connection implants. All implants were immediately loaded with a fixed restoration supported by an intra‐orally welded titanium framework. Final abutments were connected to the implants and then a titanium bar was welded to them using an intra‐oral welding unit. This framework was used as a support for the final restoration, which was fitted on the same day as implant placement. Mean marginal bone loss and radiographically detectable alteration of the welded framework were assessed using periapical radiographs immediately after surgery, and at 6‐, 12‐ and 24‐month follow‐up examinations. Results: Seven males and 13 females, with an average age of 56.5 years (SD=15.1; n=20), were consecutively treated with 80 immediately loaded implants. No fracture or radiographically detectable alteration of the welded frameworks was evident. All implants osseointegrated and a 100% implant survival rate was achieved at the 24‐month follow‐up. The accumulated mean marginal bone growth was 0.21 mm (SD 0.25, n=80). The average pocket probing depth was 1.38 mm (SD 0.41). Conclusions: The intra‐oral welding technique applied to the delivery of a final restoration of the edentulous mandible over immediately restored tapered connection implants seems to have no adverse effect on marginal bone loss and implant survival. To cite this article:
Degidi M, Nardi D, Piattelli A. Prospective study with a 2‐year follow‐up on immediate implant loading in the edentulous mandible with a definitive restoration using intra‐oral welding.
Clin. Oral Impl. Res. 21 , 2010; 379–385.
doi: 10.1111/j.1600‐0501.2009.01865.x     

Is titanium–zirconium alloy a better alternative to pure titanium for oral implant? Composition,mechanical properties,and microstructure analysis

IntroductionTitanium (Ti) is widely accepted as a biomaterial for orthopaedic and dental implants, primarily due to its capacity to integrate directly into the bone and its superior corrosion resistance. It has been suggested that titanium–zirconium alloy (TiZr), with 13–17% of zirconium, has better mechanical properties than pure Ti, but there are very few published studies assessing the suitability of TiZr for high-load- bearing implants. This study aimed to compare the mechanical properties and microstructures of TiZr and commercially pure titanium (Ti).MethodologyPure Ti and TiZr alloy discs were prepared and subjected to characterisation by nanoindentation, electron dispersive spectroscopy (EDS), X-ray diffraction (XRD), and electron backscatter diffraction (EBSD).ResultsThe TiZr alloy was found to have significantly lower elastic modulus value (p < 0.0001) and greater hardness than Ti (p < 0.05). The EDS results confirmed the presence of Zr (13–17%) in the TiZr alloy, with XRD and EBSD images showing microstructure with the alpha phase similar to commercially available Ti.ConclusionThe lower elastic modulus, higher hardness, presence of alpha phase, and the finer grain size of the TiZr alloy make it more suitable for high-load-bearing implants compared to commercially available Ti and is likely to encourage a positive biological response.     

Mandibular Fracture in Conjunction with Bicortical Penetration,Using Wide‐Diameter Endosseous Dental Implants

Prosthodontic rehabilitation of a patient with an atrophic edentulous mandible presents a significant challenge in restoring esthetics and function. The purpose of this clinical report is to describe fracture of an atrophic edentulous mandible opposing maxillary natural dentition in association with endosseous dental implants. The patient received two wide‐diameter implants in the anterior mandible for an implant‐assisted mandibular overdenture, in which the implants penetrated the inferior border of the mandible for bicortical stabilization. Three months following implant placement surgery, the patient experienced pain, swelling, and intraoral purulent drainage around the right implant. Panoramic radiograph revealed a fracture of the mandible through the right implant site and signs of infection around the left implant. The implants were removed surgically, and open reduction and fixation of the fracture site were undertaken using a titanium bone fixation plate. This clinical report demonstrates that placement of wide‐diameter implants in conjunction with bicortical penetration in a severely atrophic edentulous mandible can risk fracture of the mandible.     

Effect of Implant Design on Preservation of Marginal Bone in the Mandible

Background: Implant design and surface may have an influence on the marginal bone response during immediate functional loading. Aim: The purpose of this study was to radiographically study the effect of implant design on marginal bone preservation at immediately loaded implants used for prosthetic rehabilitation of the completely edentulous mandible. Materials and Methods: A total of 39 patients, previously treated with five implants for support of a full‐arch fixed bridge in the mandible, were included in the study. Either machined Brånemark® implants (Ma) (Nobel Biocare AB, Gothenburg, Sweden) or surface modified Astra Tech® implants with (Mi) or without a microthreaded neck (Ti) (TiOblast, AstraTech AB, Mölndal, Sweden) were used. All fixtures were loaded with a provisional glass fiber or metal‐reinforced screw‐retained restoration within 24 hours. The provisional restorations were replaced by a 12‐unit screw‐retained metal‐ceramic or metal‐resin cantilever bridge after 3 months. Bone loss from baseline to 1 year of loading was measured by means of intraoral radiographs. Only patients with baseline and 1‐year radiographs of all implants were selected for comparison. Statistical analysis was carried out on both patient and implant levels. Results: The survival rates after 1 year in function were 98.6, 100, and 100% for the Ma, Ti, and Mi implants, respectively. The overall mean bone loss after 1 year was 1.03 mm (SD 0.87; range ?0.77 to 2.5). The mean bone loss was calculated to 1.52 (SD 0.66) for the Ma group, 0.79 (SD 0.79) for the Ti group, and 0.70 (SD 1.01) for the Mi group. There was a significant difference between Ma and Ti (p = .023) and between Ma and Mi (p = .046) groups but not within Ti and Mi implants (p = .70). These conclusions were also valid when the statistical analysis was performed on implant level. Conclusions: There is no impact of design and surface on implant survival in the completely edentulous mandible. Bone preservation in immediately loaded implants in the mandible is influenced by implant design and significantly better on surface‐modified AstraTech implants compared with machined Brånemark implants. In the mandible, a microthread design of the implant collar does not seem to improve bone preservation.     

A 2-year prospective study on immediate loading with fluoride-modified implants in the edentulous mandible

Objectives: Chemically modified surfaces were introduced during the last decade to improve indications for implant treatment. The fluoride‐modified implant (Osseospeed^®) was launched in 2004 and clinical studies suggest a more rapid bone formation and stronger bone to implant contact. However, limited clinical data are available on marginal bone loss and the outcome after >1 year under immediate loading conditions is not fully understood. Hence, the purpose of this prospective study was to present implant survival and marginal bone level data when fluoride‐modified implants are supporting a fully functional rehabilitation from the day after surgery in the completely edentulous mandible. Materials and methods: Twenty‐five patients, completely edentulous in the mandible, were consecutively treated with five fluoride‐modified implants that were functionally loaded with a provisional screw retained restoration. Marginal bone loss was measured from day of surgery to 3, 6, 12 and 24 months. Implants were considered successful after 24 months if radiographic bone loss did not exceed 1 mm and no pain or mobility was caused under a torque of 20 N cm. Statistical analysis was carried out on both patient and implant levels. Results: All implants survived and mean bone loss on implant level after 3, 6, 12 and 24 months was 0.14, 0.13, 0.11 and 0.11 mm, respectively. Bone loss was only statistically significant between baseline and 3 months (P<0.001) and remained unchanged afterward. None of the implants lost >1 mm of bone after 2 years. On the patient level, the mean bone loss after 2 years was 0.12 mm (SD 0.14; range ?0.06 to 0.55) with probing pocket depth 2.45 mm (SD 0.43; range 1.3–3.1) and bleeding index 0.55% (SD 0.34; range 0–1). Conclusion: Immediate loading of fluoride‐modified implants is a predictable treatment yielding a high survival and success rate after 2 years. To cite this article:
Collaert B, Wijnen L, De Bruyn H. A 2‐year prospective study on immediate loading with fluoride‐modified implants in the edentulous mandible.
Clin. Oral Impl. Res. 22 , 2011; 1111–1116.
doi: 10.1111/j.1600‐0501.2010.02077.x     

The effect of platelet-rich plasma upon implant stability measured by resonance frequency analysis in the lower anterior mandibles

Abstract: Using a one‐stage surgical protocol, a total of 34 Brånemark Mk‐III Ti‐Unite implants with a length of 13 mm and a diameter of 3.75 mm were inserted in 10 edentulous mandibles. Of these, seven patients received four and three patients two interforaminal implants. All implants were followed with repeated stability measurements by means of resonance frequency analysis at different time interval: 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44 days. In quadrant III platelet‐rich plasma (PRP) was instilled locally before implant placement, while no PRP was added in quadrant IV to serve as control group (split‐mouth design). Results showed no statistically significant difference between the two groups. Nonetheless, both groups (PRP+control) showed a highly significant reduction of the implant stability quotient (P<0.001) between days 0 and 4. However, no difference was noted between the two groups after day 4, it may be concluded that the instillation of PRP during implant placement in the lower anterior mandible did not add additional benefit.     

Primary stability measurements of single implants in the midline of the edentulous mandible for overdentures

Objectives: To determine the primary stability of the Southern wide diameter (8 mm) implants, Neoss regular diameter (4 mm) implants, and Southern regular diameter (3.75 mm) implants placed in the midline of edentulous mandibles for single‐implant overdentures. Variables related to host site and implant characteristics were investigated to determine their influence on the primary stability of the implants. Materials and methods: A total of 36 implants were placed in the midline symphysis of the edentulous mandibles of 36 participants. Their primary stability was then measured using the magnetic Osstell mentor device. Analysis of variance (ANOVA) was used to compare the mean implant stability quotient (ISQ) scores with one‐way ANOVA for multiple comparisons. Results: The highest measurement (ISQ) of primary stability was for the Southern 8 mm wide diameter implants (84.8, SD 9.8), followed by the Neoss 4 mm regular diameter (82.3, SD 4.8) implants and the Southern 3.75 mm regular diameter implants (75.3, SD 8.4), respectively. The Southern 3.75 mm regular diameter implants had a significantly lower mean ISQ value than the same system 8 mm wide diameter (P=0.004) and the Neoss 4 mm regular diameter implants (P=0.03). No significant differences were observed between the 8 mm and the 4 mm diameter implants (P>0.05). Conclusions: Host‐site variables such as age, gender, bone volume, and quality do not appear to influence the primary stability of the implants. No clear correlation was established between ISQ values and implant diameter. To cite this article:
Alsabeeha NHM, De Silva RK, Thomson WM, Payne AGT. Primary stability measurements of single implants in the midline of the edentulous mandible for overdentures.
Clin. Oral Impl. Res. 21 , 2010; 563–566.
doi: 10.1111/j.1600‐0501.2009.01890.x     

A comparison of hydroxyapatite (HA) -coated threaded,HA-coated cylindric,and titanium threaded endosseous dental implants

PURPOSE: The purpose of this study was to compare the success of hydroxyapatite (HA) -coated and machined titanium (Ti) implants in a 5-year randomized, controlled clinical trial conducted at 2 centers. MATERIALS AND METHODS: Each of 120 edentulous patients received HA-coated threaded, HA-coated cylindric, and machined Ti threaded implants in a randomized design using 5 or 6 implants. Digital radiographs allowed for yearly measurements of bone loss. Calibrated clinicians also measured mobility, Gingival Index, Plaque Index, probing depth, and recession. A Kaplan-Meier analysis was used to compare the proportion of ailing implants (defined as less than 2 mm of alveolar bone loss over 5 years) for each type of implant design. The criteria employed to assess implant outcome included the need for successful implants to lose less than 2 mm of bone support over the 5 years following placement of the prosthesis. RESULTS: This analysis revealed that 95.2% of machined Ti threaded implants and 97.92% of HA-coated threaded implants were successful, while 99.0% of HA-coated cylindric implants experienced less than 2 mm of bone loss (P < .06). DISCUSSION: All types of implants placed in this study had success rates above 95%. CONCLUSION: Over 5 years, the success rate tended to favor HA-coated implants.     

Correlation between early perforation of cover screws and marginal bone loss: a retrospective study

Aim: This retrospective study aimed to determine the consequence of early cover screw exposure on peri‐implant marginal bone level. Material and Methods: Sixty Astra Tech^® MicroThread implants installed in partially edentulous jaws were compared: 20 implants were placed following a two‐stage procedure and were unintentionally exposed to the oral cavity (two‐stage exposed), 20 implants were placed following a two‐stage procedure and were surgically exposed after a subgingival healing time of 3–6 months (two‐stage submerged), and 20 implants were placed following a one‐stage surgical protocol (one‐stage). Digital radiographs were taken at implant placement for all implants, and after abutment surgery for the two‐stage exposed and two‐stage submerged groups or after 3 months for the one‐stage group. Bone loss mesially and distally was measured with an on‐screen cursor after calibration. Results: Mean bone re‐modelling was 1.96 mm (range: 0.2–3.2 mm) around the two‐stage exposed implants, 0.01 mm (range: 0.0–0.3 mm) around the two‐stage submerged implants and 0.14 mm (range: 0.0–1.2 mm) around the one‐stage implants. Conclusion: The unintentional perforation of two‐stage implants resulted in significant bone destruction, probably because the biological width was not considered.