Bertil Friberg

A comparison between cutting torque and resonance frequency measurements of maxillary implants. A 20-month clinical study.

Abstract Oral implant treatment ad modum Branemark was undertaken in nine patients with edentulous maxillae. Cutting torque measurements and resonance frequency analyses (RFA) were conducted at implant placement and the corresponding values were subjected to correlation analyses. The implants were also evaluated with RFA at abutment connection and at one-year follow-up in order to identify possible changes in implant stability. A total of 61 implants were inserted, of which 49 were of the Mk II self-tapping type. Two implants were lost during the study period. The cumulative torque was presented as a mean value for the upper/crestal, the middle and the lower/apical third of the implant site respectively, as well as an overall value for the whole site. The highest correlation ( r =0.84, P P =0.047) and between groups 1 and 3 ( P =0.002). When repeating the resonance frequency analyses at second stage surgery and at one-year follow-up, no significant differences were detected between any of the groups. It was shown that the stability of implants placed in softer bone seemed to “catch up” over time with more dense bone sites.

Stability measurements of one-stage Brånemark implants during healing in mandibles: A clinical resonance frequency analysis study

Using a one-stage surgical protocol, 75 implants ad modum Brånemark of three different designs were inserted in 15 edentulous mandibles of high bone density. All implants were followed with repeated stability measurements by means of resonance frequency analysis (RFA) from implant placement to connection of the fixed prostheses (3-4 months), in order to evaluate possible stability changes during healing. It was shown that the resonance frequency (RF) values slightly decreased for the majority of the implants during the study period independent of design. Consequently, the results of the present study indicated that the implants were as stable at time of placement as when measured at 3-4 months post-surgery, i.e. when the prostheses were attached. The available data support the concept of direct loading of implants when inserted between the mental interforaminal regions. One implant failed during healing and the corresponding RF measurement disclosed, at six weeks post-surgery, a value being far below the one registered at implant placement. The lowered RF value indicated the failure several weeks before the mobility was clinically diagnosed. The presence or absence of a fixture/abutment junction did not exert any influence on the marginal bone level, as determined radiographically at the end of the short investigation period.

Digitally Planned, Immediately Loaded Dental Implants with Prefabricated Prostheses in the Reconstruction of Edentulous Maxillae: A 1-Year Prospective, Multicenter Study

BACKGROUND The introduction of digital planning programs has made it possible to place dental implants in preplanned positions and being immediately functionally loaded by using prefabricated prostheses. PURPOSE The aim of this multicenter study was to describe the 1-year results of digitally planned, immediately loaded edentulous maxillae. MATERIALS AND METHODS A total of 312 implants (Brånemark System, TiUnite RP, Nobel Biocare, Göteborg, Sweden) in 52 patients from eight Scandinavian clinics were digitally planned, surgically as well as prosthetically, by using the NobelGuide (Nobel Biocare AB, Göteborg, Sweden) and received prefabricated, immediately loaded fixed prosthetic constructions in the maxillae. Individual implant stability was manually tested at 1-year follow-up. RESULTS All patients received a Procera Implant Bridge (Nobel Biocare AB); however, in two cases, the bridges were reconstructed due to misfit. In five patients, difficulties in getting the surgical guide completely in position, and in five patients, getting the prostheses completely seated, were noted. All but four patients fulfilled the 1-year follow-up. Two implants were lost during the study period, resulting in a cumulative survival rate of 99.4%. The mean marginal bone resorption from implant placement to the 1-year follow-up was 1.3 mm (SD 1.28). More than 2 mm of marginal resorption was noted in 19% of the implants at this instant. The most frequently reported complications during the first year were gingival hyperplasia and prosthesis-related problems (prosthesis screw loosening, occlusal fractures, and occlusal adjustments). CONCLUSION The 1-year results in this multicenter are promising regarding implant and bridge stability; however, the study is planned to be running for at least 3 years.

Marginal Bone Loss at Implants: A Retrospective, Long‐Term Follow‐Up of Turned Brånemark System® Implants

BACKGROUND Lately, presence of progressive bone loss around oral implants has been discussed. PURPOSE The aim of this study was to report in a large patient group with different prosthetic restorations marginal bone level and its change as measured in radiographs obtained from prosthesis insertion up to a maximum 20 years in service. Further, it also aimed to study the impact of gender, age, jaw, prosthetic restoration, and calendar year of surgery. MATERIALS AND METHODS Out of 1,716 patients recorded for clinical examination during 1999, 1,346 patients (78.4%) could be identified. A total of 640 patients (3,462 originally installed Brånemark System implants, Nobel Biocare, Göteborg, Sweden) with a follow-up of >or=5 years were included in the study, while patients with continuous overdentures and augmentation procedures were not. Distance between the fixture/abutment junction (FAJ) and the marginal bone level was recorded. RESULTS The number of implants with a mean bone level of >or=3 mm below FAJ increased from 2.8% at prosthesis insertion to 5.6% at year 1, and 10.8% after 5 years. Corresponding values after 10, 15, and 20 years were 15.2, 17.2, and 23.5%, respectively. Implant-based bone loss was as a mean 0.8 mm (SD 0.8) after 5 years, followed by only minor average changes. Mean bone loss on patient level followed a similar pattern. Disregarding follow-up time, altogether 183 implants (107 patients) showed a bone loss >or=3 mm from prosthesis insertion to last examination. Significantly larger bone loss was found the older the patient was at surgery and for lower jaw implants. CONCLUSIONS Marginal bone support at Brånemark implants was with few exceptions stable over years.

Rehabilitation of Edentulous Mandibles by Means of Five TiUnite™ Implants After One‐Stage Surgery: A 1‐Year Retrospective Study of 90 Patients

BACKGROUND Recently, the present team reported the 1-year data of one-stage surgery and mainly early loading performed in edentulous mandibles using 750 turned Brånemark System implants in 152 patients. PURPOSE The aim of the present investigation was to retrospectively evaluate the 1-year results of the same treatment technique, using Brånemark System implants with an oxidized surface (TiUnite, Nobel Biocare AB, Göteborg, Sweden). The outcome was compared with that of the former study (control) on turned implants. MATERIALS AND METHODS The present study involved 90 individuals with 450 TiUnite implants of mainly the Brånemark System Mark III design, placed in edentulous mandibles and using one-stage surgery. The prosthetic procedure was commenced as a mean 8 days after the surgical intervention. Intraoral radiographs were obtained at prosthesis insertion and at the 1-year annual checkup. Failure rates of test and control groups were compared by means of the chi-square test. RESULTS No implants were found to be mobile up to and including the first annual checkup, resulting in an implant cumulative survival rate (CSR) of 100%. The corresponding CSR for the control group was 97.5%, and this difference in implant survival was statistically significant when analyzed with the chi-square test (p < .001). A statistically significant difference was also demonstrated (p < .01) when conducting the same statistical analysis on the patient level. The mean marginal bone resorption during the first year of function was 0.49 mm (SD 0.56), and the corresponding figures for the control study were 0.39 mm (SD 0.46). The central TiUnite implant, that is, the one placed in or in close relation to the symphyseal region showed significantly more bone loss (p < .05) than the corresponding central turned implant of the control study. Distally positioned test implants demonstrated less marginal bone loss than the corresponding central one. CONCLUSIONS The outcome of 450 TiUnite implants placed in 90 patients with edentulous mandibles, of which 380 implants in 76 patients were followed for 1 year, showed an implant CSR of 100%. The figure was significantly different from the control study result of 97.5% on turned surface implants. The levels of marginal bone were close to identical for test and control implants at the 1-year checkup.

Clinical experience of TiUnite implants: a 5-year cross-sectional, retrospective follow-up study.

BACKGROUND Little is known of the long-term clinical and radiographic performance of moderately rough surface implants. PURPOSE The aim of the present retrospective investigation was to study two pioneer cohorts of patients, that is, the first patients to receive Brånemark System implants with a moderately rough surface (TiUnite, Nobel Biocare AB, Göteborg, Sweden) at the present clinic. TiUnite implants were inserted either in compromised bone sites in a mixed-mouth concept together with turned implants or used solely. Patients were followed up over a period of 5 years with regard to implant survival and the marginal bone response. MATERIALS AND METHODS Patients who received both implant types (mixed group) comprised 41 subjects, and the second group (TiUnite group) comprised 70 subjects. A total of 110 turned and 68 TiUnite implants were placed in the mixed group, and 212 TiUnite implants in the TiUnite group. Follow-up radiographs were obtained at prosthesis placement and at the 1- and 5-year check-ups, and examined by independent observers. RESULTS One turned (0.9%) and two TiUnite (2.9%) implants failed in the mixed group, and three implants (1.6%) failed in the TiUnite group, indicating no significant differences between surfaces or groups (p < .05). The mean marginal bone loss at 5 years was 0.6 mm to 0.8 mm, also indicating no significant differences for the two implant types tested in the mixed group. CONCLUSIONS Cumulative survival rates for the two implant surfaces were favorable at 5 years, and the marginal bone loss was low and similar for both implant surfaces.

Rehabilitation of edentulous mandibles by means of osseointegrated implants: a 5-year follow-up study on one or two-stage surgery, number of implants, implant surfaces, and age at surgery.

BACKGROUND In three former reports, the present team has presented the 1-year outcome of four different treatment procedures handling the edentulous mandible; that is, two-stage and one-stage surgery with turned Brånemark System® (Nobel Biocare AB, Gothenburg, Sweden) implants (Group 1 and 2) and one-stage surgery using either 5 or 4 TiUnite™ (Nobel Biocare AB, Gothenburg, Sweden) implants (Group 3 and 4). PURPOSE The aim of the present investigation was to follow up these patients for a period of 5 years with regard to implant/prosthesis cumulative survival rates, marginal bone loss calculations, clinical complications, and results related to age at surgery. MATERIALS AND METHODS A total of 385 patients, provided with 1,838 implants, were originally included in the four patient groups. All patients received fixed prostheses. The overall majority of patients had each five implants placed. Radiographs were obtained at prosthesis delivery, at the 1 and 5-year follow-up. RESULTS A total of 1,230 implants in 259 patients (67%) were possible to follow up for 5 years. Implant Cumulative Survival Rates (CSR) in 5 years for Groups 1-4 were 99.7, 97.0, 98.5, and 98.6%. The corresponding prosthesis treatment CSR was 100, 99.3, 98.5, and 98.6%, respectively. Significantly, more patients (p< .05) lost turned implants after one-stage surgery (Group 2). Frequency distributions of implants revealed that >1.2 mm bone loss was observed around 75 implants (6.4%). The moderately rough central (midline) implant showed more bone loss than other placed implants (Group 3; p< .05). The youngest half of included patients at surgery (Youngest(50%) ; n=193) presented significantly higher mortality than older patients as well as compared to normal population (p< .05). Patients in the Younger(50%) group showed also an association to patients with complete loss of all implants and patients with most implants with obvious bone loss after 5 years. CONCLUSIONS All four treatment procedures served well during the 5 years of follow-up and only eight patients (2.1%) were complete failures or showed obvious bone loss (>1.8 mm) at several implants (>2 implants), mostly observed in younger patients. The few complications in relation to implant failure and/or obvious bone loss could be associated to both local impact factors (surface, implant site, surgical protocol) as well as to host response factors (systemic health).

Turned Brånemark System® Implants in Wide and Narrow Edentulous Maxillae: A Retrospective Clinical Study

BACKGROUND The available jawbone volume is regarded as one of the most important factors when assessing the prognosis of oral implants in the rehabilitation of the edentulous maxilla. PURPOSE The aim of the current investigation was to retrospectively evaluate and compare the outcome of implants placed in edentulous maxillae with either wide or narrow jaw shapes. The marginal bone loss and implant cumulative survival rates (CSRs) were calculated and analyzed with special reference to smoking habits. MATERIALS AND METHODS The study included 75 individuals with edentulous maxillae, of which 33 patients exhibited wide (group A) and 42 patients exhibited narrow jaw shapes (group B). A total of 506 turned Brånemark System (Nobel Biocare AB, Göteborg, Sweden) implants were inserted (226 in group A and 279 in group B) and followed clinically up to 7 years. Smoking habits were recorded. Radiographs were obtained at connection of prostheses, and at the 1- and 5-year follow-up visit. The marginal bone loss was calculated for the groups and analyzed using t-test. RESULTS Twenty-eight implants were lost during the study period, revealing implant CSRs at 7 years of 94.6% (11/226) and 93.6% (17/279) for wide and narrow crests, respectively. No difference in marginal bone loss was seen between the two groups, although a trend toward more bone loss was recorded for patients with wide crests. Smoking habits were more common in group A (45%) than in group B (31%). During the first year of function, smokers lost significantly more marginal bone than nonsmokers (p = .0447), albeit this difference did not prevail (p > .05) at the end of the study period. CONCLUSIONS The implant CSRs at 7 years were equally good for the two groups of patients with various jaw shapes. Initially, smokers showed significantly more marginal bone loss than nonsmokers.

Introducing a Novel Analysis Technique for Osseointegrated Dental Implants Retrieved 29 Years Postsurgery

PURPOSE To investigate osseointegration of oral implants, which were retrieved from a patient after 29 years in situ, we use novel three-dimensional analysis methods and visualization techniques that supplement conventional two-dimensional analysis. MATERIALS AND METHODS The sample processing involved nondecalcification and embedment in resin. Conventional two-dimensional histomorphometrical methods were conducted. Additionally, the quantification was extended to three-dimensional by using synchrotron radiation micro-computed tomography (SRµCT) technique and two relevant visualization methods for the three-dimensional data were introduced. RESULTS The three-dimensional results involved three-dimensional quantification and visualization of two implant samples with methods beyond state-of-the-art. Traditional two-dimensional histomorphometrical results revealed a mean bone-implant contact (BIC) of about 50%. In most samples, bone area (BA) was lower inside the treads compared with out-folded mirror images, which were confirmed by the three-dimensional quantification. The BIC along four selected regions showed highest percentages in the bottom/valley region and lowest in the thread-peak region. Qualitative observations revealed ongoing bone remodeling areas in all samples. The apical hole demonstrated high osseointegration. CONCLUSION The novel techniques including an animation and an out-folding of BIC and BA enabled a simultaneous visualization of the three-dimensional material obtained from SRµCT data. However, the two-dimensional histological sections were needed for qualitative and quantitative evaluation of osseointegration and, thus, both methods are considered equally important.

Soft Tissue Augmentation in Connection to Dental Implant Treatment Using a Synthetic, Porous Material – A Case Series with a 6-Month Follow-Up

BACKGROUND Bony defects/concavities in the aesthetic zone of maxillae may interfere with the results of prosthetic procedures by producing shading superior to the crown. Such regions can be augmented either by bone or soft tissue autografts, allografts, or xenografts. Tissue shrinkage is thus anticipated, and a method to objectively measure the tissue change is valuable. PURPOSE The aim of this study was to evaluate the use of a synthetic, porous material made of polyurethaneurea for buccal soft tissue augmentation in connection with implant placement in the maxillary front region. Further, to measure over time the change in buccal contour using a computerized technique. MATERIALS AND METHODS Ten patients received 12 Artelon® cylinders (5 × 10 mm) in connection to implant placement. Preoperative and postoperative (at 3 and 6 months) study casts were obtained for computer measurements, using the preoperative reference model as a base. The volume created between the surfaces of the reference model and each of the two following superimposed models was measured in cubic millimeter. Differences in volume from pretreatment to 3 and 6 months, respectively, were compared. RESULTS The clinical observation during follow-up showed normal healing. The increase in mean buccal tissue volume was 50 mm(3) (SD 18) after 3 months and 43 mm(3) (SD 21) after 6 months, measured over a 6 mm × 8 mm area in the maxillary front region, in comparison to before insertion of the cylinder. The reduction from 3 to 6 months was not statistically significant (p = .17). CONCLUSION A synthetic, porous material for soft tissue augmentation was tested in connection to implant placement in the aesthetic zone of maxillae. The buccal contour was followed-up for 6 months using a computer volumetric technique on preoperative and postoperative study casts. Measured tissue volume showed an obvious increase during the study period. The material was biologically well received.