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Purpose: The purpose of the present prospective clinical study was to evaluate the radiographic and clinical outcome of immediately loaded implants in the partial edentulous mandible over a 4-year follow- up period using a modified surgical protocol, primary implant stability criteria, and splinting for inclusion. Materials and Methods: Patients in need of implant treatment in the partial edentate mandible were consecutively included in the study. The implant sites were underprepared to obtain maximal stability. Inclusion criteria for the study were torque of a least 30 Ncm before final seating of the implant and an ISQ greater than 60. A provisional fixed partial denture was delivered within 24 hours and a definitive fixed partial denture within 3 months. The patients were monitored with clinical and radiographic follow-up examinations for up to 4 years. Stability of the implants was measured with resonance frequency analysis at placement and after 6 months. Results: Ninety-six patients were evaluated, and 77 patients who met the inclusion criteria were included. A total of 111 fixed partial dentures supported by 257 Brånemark System implants (77 turned and 180 TiUnite implants) were delivered. Four (1.6%) of the 257 implants did not osseointegrate, giving an overall survival rate of 98.4% after 4 years. Three turned (3.9%) implants and 1 oxidized implant (0.6%) failed after 4 to 13 months. The average marginal bone resorption was 0.7 mm (SD 0.78) during the first year in function. Turned implants showed an average bone loss of 0.5 mm (SD 0.8) and oxidized implants an average of 0.7 mm (SD 0.8). Resonance frequency analysis showed a mean implant stability quotient of 72.2 (SD 7.5) at placement and 72.5 (SD 5.7) after 6 months of loading. Conclusion: It is concluded that immediate loading of implants with firm primary stability in partially edentulous areas of the mandible appears to be a viable procedure with predictable outcome. [ABSTRACT FROM AUTHOR]

Purpose: This article reviews the current knowledge about the influence of surgical factors on implant failure in routine cases and in those where implants have been used in conjunction with bone augmentation procedures. Materials and Methods: Clinical reports published in major scientific journals served as the basis for this review. Results: With few exceptions, most clinical reports were on screw-shaped titanium implants. High failure rates are associated with poor bone quality and the use of short implants in the athrophic maxilla, irradiation, and bone-grafting procedures of the athrophic maxilla. Evidence for high long-term failure rates of press-fit cylinders was found. Moreover, limited clinical experience, lack of preoperative antibiotics, and smoking may lead to higher failure rates. Conclusion: There is a need for further research to increase the success rates in the severly resorbed maxilla. Because of a lack of proper documentation with respect to the great majority of currently used oral implant designs, the influence of different factors and their long-term results remain unknown. [ABSTRACT FROM AUTHOR]

A proposed protocol and differentiated success criteria for long-term evaluation of oral implants are presented. The protocol and criteria were applied to a retrospective patient material treated during a 1-year period and followed for 5 years. The protocol comprised a two-stage analysis of the collected clinical data. First, a quantitative analysis of the outcome was made using a life table. Based on the information obtained during the follow-up, each implant was categorized into one of three groups: unaccounted for, failure, or survival. A qualitative analysis of the survival group was then performed by active testing against defined criteria. Depending on the modes of clinical and radiographic examinations and their results, surviving implants were either further assigned to one of three success grades or remained in the survival group. The data are presented in a four-field table at one level of success. Strict success criteria together with individual stability testing and radiographic examination of each consecutive implant should be used when a new implant system is evaluated or when a new application is explored. Radiography alone and more moderate success criteria may be used to document routine treatments, provided that an already well-documented implant system is studied. [ABSTRACT FROM AUTHOR]

The purpose of this retrospective clinical investigation was to study possible soft tissue complications and marginal bone resorption related to exposed threads of osseointegrated Brånemark oral implants during a 5-year period. Group 1 comprised 27 patients with 38 test implants that had not become completely covered with bone at implant placement. Thirty control implants in 25 of the patients were each next to a test implant and had no exposed threads initially. Group 2 comprised 51 patients with 107 test implants that had developed marginal bone loss beyond the second thread, as judged radiographically at the first annual checkup. Forty-eight control implants showed no or minor marginal bone resorption up to the first thread. Initial marginal defects and fenestrations at Brånemark implants (group 1) did not lead to mucosal problems or progressive marginal bone resorption during the first 5 years of function. Moreover, bone resorption, seen after the first year of loading at initially completely bone-covered implants, did not lead to any specific soft tissue problems, nor did it result in any further progressive bone resorption during a subsequent 4-year period. Based on the observed low incidence of soft tissue pathology at implants with exposed threads, it is suggested that bone augmentation techniques in the situations studied be used with restriction. [ABSTRACT FROM AUTHOR]

The removal torques for screw-shaped pure titanium implants inserted in rabbit tibia and the femoral part of the knee joint and the tissue response to these implants, as quantitated with light microscopic morphometry on ground sections, were compared after 6 weeks, 3 months, and 6 months. The bone surrounding the femoral intra-articular implants was mostly cancellous, while cortical bone was formed around the tibial implants. The torque needed to remove the intra-articular implants increased with time, but there was no such increase for the tibial implants. At 6 weeks, significantly less torque was needed to remove the intra-articular implants in spite of the fact that significantly more bone was found in the threads of these implants as compared with the tibial implants. When calculating the amount of bone in threads situated in the cortical and subchondral passage, more was found in the threads of the tibial implants, which corresponded to the higher removal torque. Additional light microscopic observations on implants unscrewed after 12 months in rabbit tibia indicated that rupture occurred between the implant surface and calcified bone. Findings indicate that the resistance to unscrewing is dependent on the amount of compact bone surrounding a titanium implant. [ABSTRACT FROM AUTHOR]

Screw-shaped commercially pure (CP) titanium and Vitallium® implants were inserted in the rabbit tibial metaphysis. After a healing period of 3 months, it was demonstrated that a higher torque was needed to remove the CP titanium implants (average 24.9 Ncm) compared to Vitallium implants (average 11.7 Ncm). The histomorphometric part of the study revealed more bone-to-metal contact for the CP titanium implants (average 34.7%) compared to the Vitallium implants (average 21.7%). The results obtained in this study could be explained by differences in the topography or in biocompatibility of the metals, or a combination of these two factors. [ABSTRACT FROM AUTHOR]

Clinically retrieved titanium implant cover screws (Brånemark implant system), rinsed in saline or subjected to ultrasonic cleaning and sterilization, as well as unused sterile screws were studied by scanning electron microscopy and implanted in the rat abdominal wall for 6 weeks. Irrespective of cleaning procedure, the heads of the clinically retrieved screws were covered by numerous contaminants not present on the unused screws. The reimplanted screws elicited a different tissue response than the unused screws. The tissue response to the contaminated screws was characterized by a significantly thicker fibrous capsule and by a significantly larger number of macrophages located close to the implant. Moreover, judging from their ultrastructure, studied with transmission electron microscopy, the macrophages appeared to be in a more active state when compared to those located adjacent to unused screws. [ABSTRACT FROM AUTHOR]

Several letters to the editor are presented in response to articles in previous issues including "Direct Bone Anchorage of Oral Implants: Clinical and Experimental Considerations of the Concept of Osseointegration," by Tomas Albrektsson and Lars Sennerby in the January/February 1990 issue and a response Albektsson and Sennerby to a letter to the editor about their article "Direct Bone Anchorage of Oral Implants: Clinical and Experimental Considerations of the Concept of Osseointegration."

Background New implant designs are continuously introduced to the market. It is important to evaluate and report on their clinical performance when used in everyday practice. Purpose The aim of the present study was to evaluate the clinical performance of a novel hydrophilic dental implant for 1 year. Materials and Methods A total of 49 patients previously treated with 102 hydrophilic dental implants ( Neoss Proactive, Neoss Ltd, Harrogate, UK) were retrospectively evaluated with regard to survival rate and marginal bone loss. Fifty-four implants were installed in maxillae and 48 in mandibles to replace single teeth ( n = 21), to support partial bridges ( n = 26), total maxillary bridges ( n = 2), or mandibular overdentures ( n = 2). The majority of patients ( n = 37) had implants placed in healed sites without any adjunctive procedures. In 12 patients, implants were immediately placed in extraction sockets or in conjunction with maxillary sinus floor augmentation. All implant sites had been classified according to the Lekholm and Zarb index. Baseline and 1-year intraoral radiographs were used to calculate marginal bone levels and bone loss. Implant stability quotient ( ISQ) measurements had been taken at placement and after 3 to 4 months of healing Results The implants became rapidly covered with blood at the first contact. One implant was lost, giving a cumulative survival rate ( CSR) of 99.0% after 1 year. The marginal bone loss amounted to 0.7 ± 0.6 mm with 3.5% of the implants showing more than 2 mm of bone loss and no implant more than 3 mm bone loss after 1 year. The primary stability was found to be 72.7 ± 7.5 ISQ, which slightly increased to 73.6 ± 7.2 ISQ ( NS) after 3 to 4 months of healing. The stability was significantly higher in the mandible than in the maxilla at placement and after healing. Conclusion In this limited clinical study, the use of a novel hydrophilic dental implant results in favorable short-term outcomes. [ABSTRACT FROM AUTHOR]

ABSTRACT Background: Extensive atrophy of the alveolar process may require a bone-grafting procedure prior to implant treatment. Autogenous bone grafts from the iliac crest, used as onlay block and particulate bone, have been used together with sinus-lift procedure in order to rehabilitate patients with extremely resorbed maxillae. However, there are to our knowledge no 5-year follow-up studies evaluating the extent of bone-level change in patients treated with respectively block and particulate autogenous bone grafts. Purpose: The purpose of this prospective clinical study was to conduct a 5-year follow-up analysis with focus on bone-level alteration in block versus particulate onlay bone grafts. Material and Methods: Fifteen out of originally 19 patients who were treated with iliac bone grafts and oral implants in the maxilla have been followed through the first 5 postoperative years. In a first study conducted on 19 patients, the role of platelet-rich plasma in conjunction with autogenous bone was evaluated. In this 5-year follow-up study, the marginal bone alterations have been documented at base line, 1 year and 5 years of loading to the nearest 0,1 mm at mesial and distal surfaces of the implants. Two implants were installed on each side of the midline in either block or particulate bone grafts giving test and control sides in each patient. Additionally, two implants on each side were installed in residual bone/grafted sinus floor. Result: Marginal bone alteration in the anterior maxilla appeared larger at the side augmented by block bone at baseline, and after 1 and 5 years of loading, but the change was not statistically significant. Moreover, there was a significantly higher degree of marginal alteration during the first year of loading, compared with the examinations after 5 years. Conclusion: The present follow-up study showed that there is no significant difference in the extension of resorption between block- and particulate autogenous bone grafts over a 5-year period. Most of the resorption occurred during the first year in function. [ABSTRACT FROM AUTHOR]

Background: An increasing number of studies show that immediate/early function of dental implants can be as successful as two-stage procedures. However, the results may not be universal for all implant types and it is important that new implants are tested for this treatment modality. Purpose: The aim was to evaluate an immediate/early function protocol in the maxilla and in the posterior mandible using Neoss implants (Neoss Ltd., Harrogate, UK). Materials and Methods: A total of 21 patients were provided with 69 Neoss implants (4 mm in diameter and 9–15 mm in length) and a provisional bridge within 7 days (mean 4.6 days). Sixteen implants were placed in immediate extraction sites where seven were treated with autologous bone grafts ( n = 6) or bone grafts + resorbable membrane ( n = 1). A final fixed prosthesis was made 3 to 6 months later. The patients were followed-up with clinical examinations for 18 months. In addition, the implants were monitored with resonance frequency analysis (RFA) measurements at surgery and after 1, 2, and 6 months. Intraoral radiographs were taken after surgery and after 1, 6, and 18 months. Results: One implant in an extraction site in the maxilla failed after 1 month, giving a survival rate of 98.5% after 18 months. The mean marginal bone loss was 0.7 mm (SD 0.7) after 18 months. RFA showed a mean implant stability quotient (ISQ) value of 68.1 (SD 8.8) at surgery, which increased to 73.7 (SD 5.7) after 6 months. The primary stability for maxillary and mandibular implants was similar, although mandibular implants showed slightly higher values with time. Implants in extraction sockets showed a lower initial stability than in healed sites, ISQ 65.8 (SD 7.5), which increased to ISQ 67.5 (SD 6.9) after 6 months. The failed implant showed an ISQ of 74 at placement, which decreased to 42 1 month after surgery. Conclusion: Within the limitations of the present study, it is concluded that immediate/early function with Neoss implants is a reliable method with an implant survival rate comparable to that of the traditional two-stage protocol. [ABSTRACT FROM AUTHOR]

Background: The placement of implants using a minimally invasive flapless approach has the potential to reduce operative bleeding and postoperative discomfort and minimize crestal bone loss. This article presents follow-up data on a prospective clinical study of implants placed using a flapless procedure. Methods: The original study reported on 57 patients (33 female patients with an age range of 24 to 86 years; 24 male patients with an age range of 27 to 81 years) recruited from three clinical centers (Tucson, Arizona; Gothenburg, Sweden; and Tel Aviv, Israel) who received 79 implants. After an average of 3 years and 8 months, the patients were contacted and invited to return to their respective clinics for reexamination. Thirty-seven patients with 52 implants returned for a follow-up examination; the remaining 20 patients (27 implants) were not available for reexamination and were considered study drop-outs. Results: The cumulative survival rate at the 3- to 4-year follow-up examination remains at 98.7%, reflecting the loss of one implant. The mean probing depth at abutment connection was 2.2 mm, as reported in the initial study (examination 2 at ~2 years postplacement); it was 2.4 mm at the 3- to 4-year second follow-up examination. This change was not clinically or statistically significant. Bleeding score changes also were not significant between the two intervals. The average crestal bone level was -0.7 mm at examination 2 and -0.8 mm at examination 3, a change that approached significance (P <0.06). Conclusions: Minimally invasive flapless surgery offers patients the possibility of high implant predictability with clinically insignificant crestal bone loss for up to 4 years. Proper diagnosis and treatment planning are key factors in achieving predictable outcomes. [ABSTRACT FROM AUTHOR]

Background: Fixture placement in the tuber area is one way to overcome the problem of insufficient bone volume for routine implant surgery in the posterior maxilla due to severe resorption of jawbone and an extensive enlargement of the maxillary sinus. However, little is known about the long-term results. Purpose: The aim of this study was to retrospectively evaluate the survival rate and marginal bone conditions at fixtures placed in the tuber region of the maxilla. Material and methods: Twenty-one patients previously treated with at least one implant in the tuber region of the maxilla were included in this retrospective analysis. A total of 23 standard Brånemark System fixtures with a turned surface had been surgically placed in the tuber regions and 71 additional implants in adjacent areas to support fixed dental bridges. All implants were allowed to heal for 6–8 months before abutment connection and following prosthetic treatment. The patients were radiographed after 1–12 years for evaluation of marginal bone levels. In addition, the relation between the apex of the fixture in the tuberosity area and the posterior border of the maxilla was measured. Results: Twenty of the 21 patients representing 22 tuber and 64 additional implants were radiographically evaluated. No implants in the tuber areas were lost during the follow-up whereas two fixtures in the anterior region had to be removed, one before loading and the other after 4 years of loading not interfering with the prosthesis stability. The mean marginal bone level at tuber implants was situated on average 1.6 mm (SD 1.1, n=22) from the abutment-fixture junction, whilst the other implants showed an average bone level of 1.9 mm (SD 0.8, n=64). The results were similar when comparing partially and totally edentulous patients. Conclusion: The present retrospective study shows good clinical outcome with standard Brånemark fixtures placed in the tuber region of the posterior maxilla using a two-stage procedure. In appropriate cases where bone of adequate volume and density is available, our data indicate that the technique can be used as an alternative to more extensive surgery and especially to the sinus lift procedure. However, prospective comparative studies are needed in order to evaluate the efficacy of the described technique for this purpose. [ABSTRACT FROM AUTHOR]

Background: Previous studies have shown the formation of more bone contacts with a moderately rough and porous titanium surface, created by anodic oxidation, as compared with nonmodified turned titanium control surfaces. The mechanisms leading to a stronger bone response to oxidized titanium are not well understood. Purpose: The aim of the study was to describe the early events of bone integration of titanium implants with oxidized and turned surfaces. Materials and Methods: Nine adult New Zealand White rabbits and 18 implants were used in the study. One oxidized and one turned threaded titanium implants, which had been placed in the right tibial metaphysis, were analyzed in the present study. The implants were retrieved after 7, 14, and 28 days for light microscopic examination and histomorphometric measurements in ground sections. Results: Integration of oxidized implants was seen to occur as direct bone formation on the surface, while the integration of turned implants was a result of bone ingrowth from preexisting bone and bone marrow. For oxidized implants, an almost acellular, darkly stained layer was seen after 7 to 14 days, which later became populated with osteoblasts. The presence of osteoid seams indicated appositional bone growth from the substrate toward the surrounding tissues. The bone contact values were higher for oxidized implants, and the bone area values were higher for turned implants. Conclusions: The present study confirms the idea that implant surface modification alters the bone tissue response to titanium. The early bone formation following surgery occurs directly on the moderately rough oxidized surface, while turned titanium surfaces are integrated by the ingrowth of bone from the adjacent bone marrow and preexisting bone tissues. [ABSTRACT FROM AUTHOR]

The article explores the review papers about the state of the art of oral implants. One of the review papers suggests one long-term documented oral implant system, while another presents criteria for success for modern oral implants, and the third one warns the clinicians on the use of certain osseointegrated designs. The authors also cite the new oral dental implants from suppliers like Nobel Biocare, Straumann AG, and Biomer 3i.

Purpose: The present retrospective clinical study was undertaken to evaluate the survival rate and marginal bone conditions around Nobel Direct one-piece implants. The purpose was also to compare the results with when these implants are used for immediate/early loading with implants allowed to heal before loading. Material and methods: Forty-three consecutive patients previously treated with 117 Nobel Direct implants at four different centres were evaluated. The implants had been used in both jaws for treatment after loss of single and multiple teeth. Immediate/early loading (within 2 weeks) with a provisional crown/bridge was applied to 95 implants, while 22 implants healed unloaded for 6 weeks to 6 months before loading. Calculations of marginal bone loss were performed in radiographs taken at placement and after an average of 10.2 months (range 1–18 months) of loading. Results: Six (5.1%) of the 117 implants were removed during the follow up. All failed implants belonged to the immediate/early loading group giving a failure rate of 6.3% for this group and 0% for two-stage implants. The failure rate was higher for flapless (7.9%) than for flap surgery (0%). The marginal bone loss was −2.4 mm (SD 1.5) for all implants, while 37.6% showed more than 3 mm of loss during the follow up. Bone loss increased with time of follow up. Implants subjected to immediate/early loading showed more bone loss than two-stage implants: −2.6 mm (SD 1.5) vs. −1.6 mm (SD 1.1). Moreover, 41.3% of immediately loaded and 22.7% of two-stage implants presented with more than 3 mm of bone loss. Conclusions: This short-term retrospective analysis showed a poor clinical outcome of Nobel Direct implants. Extensive marginal bone loss (>3 mm) was found around more than 1/3 of the implants evaluated. Less resorption and no failures were experienced when implants were allowed to heal from 6 weeks to 6 months before occlusal loading. Within the limitations of the present study design, data indicate that immediate loading, the use of this implant for multi-unit constructions and flapless surgery are risk factors for failure of Nobel Direct implants. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this prospective study was to evaluate the Nobel Direct® and Nobel Perfect® one-piece implants (OPIs) when used for immediate function. Material and methods: Forty-eight patients were provided with 115 OPIs for loading with a provisional crown or a bridge within 24 h and followed for at least 12 months with clinical and radiographic examinations. A group of 97 patients previously treated under identical conditions by the same team with 380 two-piece implants (TPIs) for immediate loading in the mandible and maxilla served as the reference group. Results: Six (5.2%) OPIs failed during the follow-up due to extensive bone loss. Five (1.3%) implants failed in the reference group. After 1 year, the mean marginal bone loss was 2.1 mm (SD 1.3) for OPIs and 0.8 mm (SD 1) for TPIs. 20% of OPIs showed more than 3 mm of bone loss compared with 0.6% for TPIs. When compensating for vertical placement depth, OPIs still showed a lower marginal bone level and thus more exposed threads than TPIs. Depending on the criteria used, the success rate for OPIs was 46.1% or 72.2% compared with 85% or 91.6% for TPIs. Conclusions: The Nobel Direct® and Nobel Perfect® OPIs show lower success rates and more bone resorption than TPIs after 1 year in function. Factors such as implant design, insertion depth, rough surface towards the mucosa, in situ preparation and immediate loading may have an influence on the clinical outcome. [ABSTRACT FROM AUTHOR]

Background: A recently introduced implant, the NobelDirect (Nobel Biocare AB, Göteborg, Sweden), has previously been documented with substantial bone resorption in a large number of operated cases. PurposeL The aim of this study was to evaluate the failure rate of NobelDirect implants in a retrospective multicenter survey. Materials and Methods: A total of 550 NobelDirect implants consecutively placed in over 269 patients at 18 centers were evaluated with regard to failure rate after an average follow-up of about 1 year. Results: The overall failure percentage was 10.9% (59 failures). The 58 implants not loaded directly showed only one failure (1.7%) versus 58 failures (11.8%) of those implants that were loaded directly. A chemical x-ray photoelectron spectroscopy analysis of an implant from the original batch showed up to 3.5% silicon at parts of the implants. A retrieval analysis of one implant removed at 2 years after placement demonstrated bone resorption down to the level of the fifth thread. Conclusions: It is concluded that the NobelDirect implant, if placed with a punch procedure, ground down in situ, and loaded directly, shows an unusually high failure rate at 1 year. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to compare the performance of two non-splinted implants used as retention for a mandibular overdenture when applying conventional or early loading protocols. Material and methods: Twenty edentulous patients were treated with two unsplinted and non-submerged implants (15 mm long, TiUnite RP, Brånemark System) in the anterior mandible. The patients were randomly allotted into two groups: (i) test group (Group A), in which the overdenture was connected 1 week after surgery, and (ii) control group (Group B), in which the overdenture was connected after 12 weeks of healing. Resonance frequency analyses (RFA) for implant stability measurements were performed at implant surgery and after 1, 3, 6, 9 and 12 months. Marginal bone levels were evaluated at implant surgery and after 6 and 12 months. Results: No implant from either group was lost and all implants showed less than 1 mm of marginal bone resorption during the first year. The mean implant stability quotient (ISQ) values at implant surgery were 76.2±2.8 for Group A and 75.6±4.5 for Group B. The 12-month measurements showed 76.4±2.5 ISQ and 76.4±2.8 ISQ for Groups A and B, respectively. There were no statistically significant changes between or within the groups with time. There were no differences in marginal bone loss, which was on average 0.3 mm for both groups after 1 year. Conclusion: Although a limited number of patients were followed for 1 year only, the results of the present study indicate that early loading of two unsplinted 15 mm long implants with an overdenture does not negatively affect implant stability or marginal bone conditions when compared with implants subjected to 12 weeks of healing before loading. [ABSTRACT FROM AUTHOR]

Background: Prosthetic treatment of the edentulous maxilla may require bone augmentation to enable placement and integration of dental implants. This constitutes a complex healing situation, and resorption of the grafted bone and failure of the implants often occur. The application of autogenous platelet-rich plasma (PRP) has been suggested to improve incorporation and preservation of bone grafts. Purpose: The aim of this controlled clinical study was to evaluate whether PRP in conjunction with grafting of particulated autogenous bone to the maxilla could improve the integration and clinical function of dental implants. An additional aim was to compare block bone grafts without PRP with PRP-treated particulated bone. Material and Methods: Nineteen consecutive patients were included in the study and treated with iliac bone grafts and dental implants in the maxilla according to a split-mouth design. In the anterior maxilla, particulated bone mixed with PRP (test) was compared with only block grafts without additional PRP (control). In the posterior maxilla, particulated bone grafts with (test) or without (control) PRP were placed as sinus inlay grafts. After 6 months of healing, 152 implants (8 implants/patient) (TiOblast™, Astra Tech AB, Mölndal, Sweden) were placed. Test (PRP; 76 implants) and non-PRP (76 implants) sides were evaluated and compared by implant survival rate, marginal bone level, and implant stability using resonance frequency analysis (RFA) during I year in function. Results: Two control implants in control sites in two patients were lost at abutment connection. After 1 year in function, no further implants were lost, giving an overall survival rate of 98.7%. The marginal bone level measurements showed no significant differences, although there was a tendency toward less resorption on PRP sides. RFA measurements showed statistically significantly higher implant stability quotient values for PRP sites at abutment connection in the anterior but not in the posterior regions. Conclusions: The present clinical study showed that a high implant survival rate and stable marginal bone conditions can be achieved after 1 year of loading in the maxilla following autogenous bone grafting whether or not PRP is used. RFA measurements revealed differences at abutment connection, which could be explained by the type of graft rather than as an effect of PRP. Although no obvious positive effects of PRP on bone graft healing could be demonstrated, the handling of the particulated bone grafts was improved. [ABSTRACT FROM AUTHOR]

Background: Histologic studies have demonstrated the possibility to reestablish direct bone-implant contacts after ligature-induced periimplantitis. The influence of the reosseointegration on the stability of implants is not known. Purpose: The aim of the present investigation was to study bone tissue and associated implant stability alterations that occurred during induction and resolution of periimplantitis using resonance frequency analysis (RFA), radiography, and histology. Materials and Methods: Three implants with smooth (turned) or roughened (SLAR) surfaces were placed in each side of the edentulous mandible of four dogs. Experimental periimplantitis was induced for 3 months. Five weeks later, the animals were treated with antibiotics and surgical therapy and were followed for another 6 months. Periapical radiographs and RFA were used to evaluate marginal bone levels and implant stability throughout the study period. After termination, the tissue-implant interface was evaluated by light microscopy in ground sections. Results: There was a linear relationship between radiographic and RFA findings because continuous loss of marginal bone and a decrease in implant stability were observed for both implant surfaces during the periimplantitis period. Antibiotic treatment and surgical therapy resulted in some reosseointegration, which was more marked for the SLA surface. The resonance frequency values corresponded well to the histometric measurements because reosseointegration resulted in an increase in implant stability. Conclusions: The findings from the present study indicate a linear relationship between marginal bone level and resonance frequency value. It is suggested that the RFA technique is sensitive and may be used to detect even a minor change in the level of bone-implant contact. [ABSTRACT FROM AUTHOR]

Background: Zirconia ceramics are biocompatible and have mechanical properties that make them suitable as materials for dental implants. Little is known about how surface modification influences the stability and bone tissue response to zirconia implants. Purpose: The objective of the investigation was to histologically and biomechanically evaluate the bone tissue response to zirconia implants with two different surface modifications in comparison with machined, nonmodified zirconia implants and oxidized titanium implants. Materials and Methods: Threaded zirconia implants with a diameter of 3.75 mm with either a machined surface (Zr-Ctr) or one of two surface modifications (Zr-A and Zr-B) were manufactured. Oxidized titanium (Ti-Ox) implants 3.75 mm in diameter were also used. The implants were characterized with regard to surface topography using an interferometer. Twelve rabbits received 96 implants using a rotational scheme, two in each tibia and two in each femur. The implants in six rabbits were subjected to removal torque (RTQ) tests after a healing period of 6 weeks. The implants in the remaining six animals were removed en bloc for light microscopic analysis. Back-scatter scanning electron microscopic (BS-SEM) analyses were used to evaluate the state of the bone-implant interface at the modified zirconia implants after RTQ testing. Results: The Ti-Ox and Zr-A implants showed the highest surface roughness, followed by the Zr-B implants and, finally, the Zr-Ctr implants. The nonmodified ZrO2 implants showed statistically significant lower RTQs than all other implants. No significant differences in bone-implant contact or bone area filling the threads were observed. BS-SEM showed intact surface layers of the surface-modified implants after RTQ testing and revealed fracture of the interface bone rather than a separation. Conclusion: The present study showed a strong bone tissue response to surface-modified zirconia implants after 6 weeks of healing in rabbit bone. The modified zirconia implants showed a resistance to torque forces similar to that of oxidized implants and a four- to fivefold increase compared with machined zirconia implants. The findings suggest that surface-modified zirconia implants can reach firm stability in bone. [ABSTRACT FROM AUTHOR]

Background: The influence of thread design at the millimeter level and surface topography at the micrometer level on bone integration and the stability of dental implants have been studied extensively. However, less is known about the influence of implant structures in the range of 50 to 200 µm. Purpose: The present in vivo investigation was undertaken to study if bone formation and implant stability were influenced by 110 (S1) and 200 (S3) µm-wide and 70 µm-deep grooves positioned at a thread flank of oxidized titanium implants. Materials and Methods: Eighteen rabbits and oxidized titanium implants (3.75 mm in diameter and 7 mm long) were used in the study. Nine rabbits received three control implants and three test implants with a 110 µm-wide groove added to one thread flank. The remaining nine rabbits received three control implants and three test implants with a 200 µm-wide groove. The animals were followed for 6 weeks. Removal torque (RTQ) tests were applied to two of the implants in each leg. The remaining implant per leg was retrieved for histology. The degree of bone fill within the grooves and corresponding bone formation at the opposing surfaces, the bone area within the threads, and the degree of bone-implant contact were calculated for each implant. Results: The histologic analyses revealed an affinity for bone formation within the grooves. The RTQ tests showed that the peak RTQ was approximately 30% higher for the S1 implants compared with control implants without a groove. The difference was statistically significant (p < .05) for tibial and pooled implants. A similar but smaller and not statistically significant effect, approximately 8%, was measured for the S3 implants. The histomorphometric measurements confirmed the observed affinity of bone for the grooves. For S1 implants, 78.7 ± 15.8% of the grooves were filled with bone, whereas only 46.2 ± 27% of the corresponding flank surface showed the presence of bone (p < .05). The corresponding figures for S3 and control implants were 72.7 ± 25.1% and 48.5 ± 13.6%, respectively (p < .05). The degrees of bone-implant contact and bone area within the threads were similar for test and control implants. Conclusion: It is concluded that 110 and 200 µm-wide and 70 µm-deep grooves at oxidized implant surfaces stimulated bone to preferentially form within and along the groove in the rabbit model. The 110 µm-wide groove was shown to increase the resistance to shear forces significantly. It is suggested that implants with such a groove may be one way to optimize implant stability in suboptimal clinical conditions. [ABSTRACT FROM AUTHOR]

Background: Long healing periods and submerged implant placement are commonly used in the maxilla. This extends the time of oral handicap and makes the use of immediate loading protocols an attractive option. The current clinical literature on direct loading of dental implants in the maxilla is limited. Purpose: The purpose of this prospective clinical study was to evaluate the clinical outcome and stability of directly loaded Brånemark System* or Replace Select* Tapered implants (Nobel Biocare AB, Göteborg, Sweden) after using a modified surgical protocol and inclusion by primary implant stability. In addition, a reference group treated according to a two-stage protocol was used for comparison. Materials and Methods: Twenty patients planned for prosthetic rehabilitation with implant-supported bridges in the edentulous maxilla participated in the study group. The final decision on immediate loading was made after implant placement using insertion torque and resonance frequency analysis (RFA) as acceptance criteria. All patients were included, and 123 oxidized implants (TiUnite Nobel Biocare AB) were placed using a surgical protocol for enhanced primary stability. A screw-retained temporary bridge was delivered within 12 hours and a final bridge within 3 months of implant placement. The patients were monitored through clinical and radiographic follow-up examinations from implant placement to at least 12 months. Marginal bone level was measured at bridge delivery and after 12 months of loading. Additional RFA measurements were made after 6 months of loading. A reference group comprising 20 patients with 120 implants treated according to a two-stage protocol was used for comparison. Results: One (0.8%) of the 123 implants in the study group failed, and no implant was lost in the reference group. The cumulative survival rates after 12 months of loading were thus 99.2% and 100% for immediate and delayed loading protocols, respectively. The marginal bone resorption was 0.78 (SD 0.9) in the study group and 0.91 {SD 1.04) in the reference group. RFA showed a mean value of 62.9 (SD 4.9) implant stability quotient (ISQ) at placement and 64.5 (SD 4.8) ISQ after 6 months for immediately loaded implants (not significant). The corresponding figures for the reference groups were 61.3 (SD 8.8) ISQ and 62.6 (SD 7.0) ISQ (not significant). There were no statistically significant differences between the groups at any time point. Conclusion: The use of six to seven implants for immediate loading of a fixed provisional bridge is a viable option for implant treatment of the edentulous maxilla, at least when good primary implant stability can be ensured. [ABSTRACT FROM AUTHOR]

Background: Surface modification of titanium implants by anodic oxidation may lead to enhanced bone integration. For instance, in vivo studies have demonstrated formation of more bone contacts in less time than for turned control implants. In addition, oxidized implants have shown a higher resistance to torque forces, indicating a strong interlock between bone and the oxide layer. However, the structure of the oxidized titanium-bone interface in high resolution is not known. Purpose: The aim of the study was to analyze the human bone-oxidized titanium interface at a high-resolution level. Of particular interest was the relationship between bone tissue and the pores of the surface oxide. Material and Methods: Twelve clinically retrieved implants with an oxidized surface (TiUnite, Nobel Biocare AB, Göteborg, Sweden) were used. Seven were regular dental implants and five were experimental mini-implants and had been subjected to immediate, early, or no loading. They were retrieved after 5 to 9 months of healing and were processed and analyzed using light microscopy, scanning electron microscopy (SEM) in normal and back-scatter (BS-SEM) modes, and energy-dispersive x-ray (EDX) analysis techniques. Results: Bone formation was observed to occur from adjacent bone structures toward the implant surface, and it was evident that bone formation had occurred at the implant surface. SEM, BS-SEM, and EDX revealed that mineralized bone had grown into the pores of the surface oxide layer, including pores with small diameters (< 2 µm). Conclusions: The clinically retrieved oxidized implants showed evidence of bone growth into the pores of the surface oxide layer. The findings indicate the establishment of a strong interlock between the bone and the oxidized titanium implant, which is suggested to be beneficial for clinical performance. [ABSTRACT FROM AUTHOR]

Background: Placement of implants with a minimally invasive flapless approach has the potential to minimize crestal bone loss, soft tissue inflammation, and probing depth adjacent to implants and to minimize surgical time. Purpose: The aim of this multicenter study was to evaluate implant placement using a minimally invasive one-stage flapless technique up to 2 years. Materials and Methods: Fifty-seven patients ranging in age from 24 to 86 years were recruited from three clinical centers (Tucson, AZ, USA; Tel Aviv, Israel; Göteborg, Sweden). Seventy-nine implants were placed. A small, sharp-tipped guiding drill was used to create a precise, minimally invasive initial penetration through the mucosa and into bone (Nobel Biocare, Yorba, Linda, CA, USA). Implants were placed according to the manufacturer's instructions, wkh minimal countersinking. The parameters evaluated were total surgical time, implant survival, bone quality and quantity, implant position by tooth type, depth from mucosal margin to bone crest, implant length, probing depth, inflammation, and crestal bone changes. At 2 years, for 79 implants placed in 57 patients, the cumulative success rate using a minimally invasive flapless method was 98.7%, indicating the loss of 1 implant. Changes in crestal bone for 77 baseline and follow-up measurements were insignificant (radiograph 1: mean 0.7 mm, SD 0.5 mm, range 2.8 mm, minimum 0.2 mm, maximum 3.0 mm; radiograph 2: mean 0.8 mm, SD 0.5 mm, range 3.4 mm, minimum 0.12 mm, maximum 3.5 mm). Using descriptive statistics for 78 patients (one implant lost), mean changes for probing depth and inflammation were clinically insignificant. The average time for implant placement was 28 minutes (minimum 10 minutes, maximum 60 minutes, SD 13.1 minutes). Average depth from mucosal margin to bone was 3.3 mm ( SD 0.7 mm, minimum 2 mm, maximum 5 mm, range 3 mm). Thirty-two implants were placed in maxillae and 47 in mandibles. Conclusions: The results of this study demonstrate that following diagnostic treatment planning criteria, flapless surgery using a minimally invasive technique is a predictable procedure. The benefits of this procedure are lessened surgical time; minimal changes in crestal bone levels, probing depth, and inflammation; perceived minimized bleeding; and lessened postoperative discomfort. [ABSTRACT FROM AUTHOR]

Background: Studies indicate that implants placed at the time of extraction have high success rates. Implants must be stable at the time of insertion. Presently there are no data indicating the degree of implant stability when implants are placed at the time of extraction. This study evaluated changes in stability of implants from implant placement to abutment connection utilizing resonance frequency analysis (RFA). The unit of measurement was the international stability quotient (ISQ). Methods: Prior to treatment, patients were given medical history and dental evaluations. Periapical and panogram radiographs were taken. Fifty-two patients requiring extraction of one or two teeth and implant placement immediately after extraction were enrolled in this study. Under conscious sedation and local anesthesia or local anesthesia alone, teeth were atraumatically removed and the extraction sockets were debrided. A total of 73 dental implants (57 in the maxilla, 16 in the mandible) were placed. Using a one-stage approach, all implants were placed within the patient's alveolar envelope and were never placed directly into extraction sockets. All implants were placed into contained extraction sites. Bone augmentation procedures were not performed. After implant insertion, the RFA electronic transducer was attached to the head of the implant with the retaining screw. The device was attached to a computer designed to register RFA scores in ISQ units. RFA measurements were taken at implant placement and abutment connection. Bone qualities, quantity, implant length and width as well as site of placement were recorded. Results: The average interval between implant insertion and abutment connection was 5.6 months (SD 2.05). Two implants were lost between implant insertion and 1 year. At 2 to 3 years, the cumulative survival was 97.2%. Resonance frequency measurements at implant placement showed a mean primary stability of 62.0 (SE 1.1; range 43 to 83 ISQ) and a mean secondary stability after 1 year of 64.0 (SE 1.2; range 40 to 98 [SQ) for all implants. The increase was marginally significant (generalized estimating equation z-statistic 1.79; P value = 0.07). Conclusions: Implants placed at the time of extraction and inserted into native bone and not directly into extractions sockets have a high degree of initial stability as evidenced by RFA measurements. Implants with initial high ISQ levels revealed a slight drop in levels over time, while implants with levels lower than 60 had increases in levels between implant insertion and abutment connection. At 2 to 3 years the cumulative survival rate was 97.2%. [ABSTRACT FROM AUTHOR]

The objective of this study was to analyze the development of implant stability by repeated resonance frequency analysis (RFA) measurements during 1 year in 23 patients treated according to an immediate/early-loading protocol. The objective was also to evaluate the possible differences between failing and successful implants. Eighty-one Brånemark System implants were placed in 23 patients for immediate/early-occlusal loading in all jaw regions. Thirty of the implants were placed in extraction sockets and 62 were subjected to GBR procedures. Apart from clinical and radiographic examinations, the patients were followed with RFA at placement, prosthesis connection and after 1–3, 6 and 12 months. Statistical analyses were carried out to study the possible differences between implants that failed during the study period and implants that remained successful. Nine implants failed (11.2%) during the 1 year of loading. RFA showed a distinct different pattern between the implants that remained stable and the implants that were lost. The implants that failed during the course of the study showed a significantly lower stability already after 1 month. Within the limitations of this study, it is concluded that failing implants show a continuous decrease of stability until failure. Low RFA levels after 1 and 2 months seem to indicate an increased risk for future failure. This information may be used to avoid implant failure in the future by unloading implants with decreasing degree of stability with time as diagnosed with the RFA technique. To cite this article: Glauser R, Sennerby L, Meredith N, Rée A, Lundgren AK, Gottlow J, Hämmerle CHF. Resonance frequency analysis of implants subjected to immediate or early functional occlusal loading. Successful vs. failing implants. Clin. Oral Impl. Res. [ABSTRACT FROM AUTHOR]

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Presents a study which evaluated oxidized titanium dental implants subjected to loading immediately following surgery or after two months of healing and removal after five to nine months loading. Materials and methods; Results; Conclusions.

Presents a study which evaluated the outcome over one year of oxidized titanium implants when loaded with a fixed full-arch bridge in the maxilla after dental implant placement. Materials and methods; Results; Conclusions.

Presents a study on the short-term success rates of TiUnite-surfaced immediate occlusally loaded Brånemark System Mk IV dental implants placed in various regions of the jaws. Materials and methods; Results; Conclusions.

Background: Immediate/early loading protocols are becoming frequently used in implant dentistry, but tile prerequisites for achieving good results and the limitations of such protocols are not fully known. Moreover, the terminology used in immediate/early loading is still confusing. Propose: The purpose of this article is to present the outcome of a consensus meeting on immediate/early loading. Materials and Methods:A consensus meeting was organized during the Sociedad Espanola de Implantes World Congress in Barcelona on May 23, 2002, with the objective to present and discuss the experiences from immediate/early loading protocols in dental implant treatment. The purpose was also to discuss definitions of the terminology used in immediate/early loading. The consensus meeting agenda included presentations from invited experts, followed by a consensus discussion. Results: A consensus statement was agreed on. Conclusions: Multiple independent investigators have demonstrated that immediate/early loading of implants is possible in many clinical situations; however, additional documentation is required. [ABSTRACT FROM AUTHOR]

Editorial. Deals with the successful outcomes with osseointegrated dental implants. Description of early implant treatment protocols; Way to overcome the disadvantages of conventional implant treatment; Information on the journal 'Clinical Implant Dentistry and Related Research.'