Astra Tech and Brånemark System implants: a prospective 5-year comparative study. Results after one year

Background: Endosseous dental implants are used frequently, and many implant systems are available. The scientific documentation of the implant system presents a great variation, and it is often difficult to compare studies of different systems. Purpose: The aim of this study was to compare two Swedish implant systems (Astra Tech and Brånemark System± implants), in a prospective randomized study. Materials and Methods: Sixty-six patients were equally distributed between the two implant systems; 184 Astra Tech and 187 Brånemark System implants were used. The patients have been followed annually with clinical and radiographic examinations. The results after 1 year are reported. Results: The abutment procedure was found to be easier and less time-consuming with Astra Tech than with Brånemark implants. The operation times in minutes (mean ± SEM) were for the respective implant 35 ± 4.0 and 51 ± 4.8 in the maxilla and 32 ± 3.8 and 43 ± 2.4 in the mandible. The differences in both cases were significant: p <.02 and p <.05, respectively. The failure rate for Astra Tech implants was 0.5% and for Brånemark implants 4.3%. The difference was significant (p <.05); however, taking into account that five of the eight implant losses in the Brånemark implant group occurred in one patient, an intraindividual correlation cannot be excluded. Therefore, this result should be interpreted with caution. The marginal bone level changes were examined already from the fixture installation. The major bone loss was found between fixture installation and baseline. This bone loss was several times greater than the bone loss between the baseline and the 1-year follow-up. The total bone loss during the observation period did not differ significantly between the systems, but they had different resorption patterns. The bone loss in the upper jaw between baseline and 1-year follow-up was 0.22 ± 0.14 and 0.03 ± 0.09 mm for the Astra Tech and Brånemark implants, respectively. In the lower jaw, the loss was -0.31 for both systems. The frequency of plaque accumulation and bleeding on probing did not differ between the implant systems. Conclusions: Abutment connection with Astra Tech implants was simpler than the corresponding surgery with Brånemark System implants and the survival rate of Astra Tech implants was higher than that of Brånemark system implants.     

Astra Tech and Brånemark system implants: a 5-year prospective study of marginal bone reactions

Abstract: This paper describes the 5‐year results of a comparative study between Astra Tech and Brånemark system implants. The aim was to compare the systems primarily with regard to bone level changes, and also with regard to other variables of interest. Sixty‐six patients with edentulous jaws were included in the study. Randomisation schedules were used to allocate the patients to the two implant systems. 184 Astra Tech implants with a titanium‐blasted surface and 187 Brånemark implants with a turned surface were used. The implants were inserted with a two‐stage technique and the insertion followed the routines for the respective implant system. All patients were provided with full‐arch fixed bridges. All patients were followed up with clinical and radiographic examinations from fixture insertion to the 5‐year follow‐up. The total mean bone level change in the upper jaw between fixture insertion and the 5‐year examination was ?1.74±0.45 mm at the Astra implants and ?1.98±0.21 at the Brånemark implants. The corresponding values for the lower jaw were ?1.06±0.19 for Astra and ?1.38±0.17 for Brånemark. The major postoperative changes of the marginal bone level took place between fixture insertion and baseline. During this period, there was also a different pattern of bone remodelling between the implant systems. Between baseline (prosthesis connection) and the 5‐year examination, the marginal bone level changes were small, with no difference between the implant systems. The implant stability was examined with the supraconstructions removed. At the 5‐year examination, the survival rate for Astra Tech implants was 98.4% and for the Brånemark implants it was 94.6%. The difference was not statistically significant.     

Marginal bone reaction to oral implants: a prospective comparative study of Astra Tech and Brånemark System implants

Abstract: In earlier studies of Astra Tech and Brånemark System implants, high survival rates and small marginal bone changes have been demonstrated. The aim of this study was to compare the two systems, primarily with regard to marginal bone changes, but also with regard to other clinical variables of interest. The present paper describes the results after three years. Sixty‐six patients were included in the study and randomly assigned to treatment with Astra Tech implants (n=184) or Brånemark System implants (n=187). The marginal bone level was radiographically examined at fixture insertion, at abutment connection, at baseline (delivery of the prosthetic construction) and at 1‐ and 3‐year follow‐up examinations. Between fixture insertion and the baseline examination, the pattern of marginal bone resorption differed between the two systems. However, there was no significant marginal bone change between baseline and the 1‐year examination or between the 1‐ and 3‐year examinations. Nor were there any differences between the systems. The mean bone loss in the upper jaw between BL (baseline) and 3 years was 0.2±0.3 mm for Astra Tech implants and 0.2±0.1 mm for Brånemark System implants. The corresponding figures for the lower jaw were 0.3±0.2 mm and 0.2±0.1 mm. The survival rate of Astra Tech implants was significantly higher (98.9%) than for Brånemark System implants (95.2%). However, five of the nine implant losses in the Brånemark group occurred in one patient. For that reason, this result must be interpreted with caution. The number of patients with implant losses did not differ significantly between the systems. Few complications were recorded up to 3 years.     

A clinical, radiographic, and microbiologic comparison of Astra Tech and Brånemark single tooth implants

Background: The soft tissues around single tooth implants differ fundamentally from the gingiva around natural teeth. There are very limited data comparing soft tissues around different implant systems. Aim: To assess whether the design characteristics of dental implants, particularly the implant‐abutment junction, may affect the dimensions and health of the peri‐implant soft tissues and radiographic bone levels. Subjects and Method: Fifteen Astra Tech and 15 Brånemark single tooth implants that had been in function for a minimum of 2 years in 30 partially dentate subjects were examined for plaque accumulation, probing depth, and bleeding on probing and compared to contralateral healthy teeth. Standardized radiographs were taken to measure the most coronal bone to implant contact on the mesial and distal surfaces. In addition, samples of subgingival plaque were taken on paper points and examined by darkfield microscopy. Results: Significantly higher mean probing depths (p < .001) and higher mean percentage of spirochetes (p= .003) were found at implants compared to teeth. In this sample, the Brånemark implants had significantly higher probing depths than the Astra Tech implants (median and interquartile range: Astra Tech 2.7 mm [2–3], Brånemark 3.3 mm [3–3.7] p= .026) and the most coronal bone to implant contact was closer to the implant–abutment junction in the Astra Tech implants (Astra Tech 0.6 mm [0.2–0.9], Brånemark 1.6 mm [1.4–2.0]. p < .001). Conclusion: Although there were statistically significant differences between the two implant systems, the clinical differences were small and probably reflect differences in the biologic width in relation to the location and design of the implant‐abutment junction.     

The peri‐implant hard and soft tissues at different implant systems. A comparative study in the dog.

The aim of the present experiment was to study the marginal peri-implant tissues at intentionally non-submerged (1-stage implants) and initially submerged and subsequently exposed implants (2-stage implants). 5 beagle dogs, about 1-year-old, were used. 3 months after the extraction of the mandibular premolars, fixtures of the Astra Tech Implants Dental System®, the Brånemark System® and the Bonefit®-ITI System were installed. In each mandibular quadrant, 1 fixture of each implant system was installed in a randomised order. The installation procedure followed the recommendations given in the manuals for each system. Thus, following installation, the bone crest coincided with the fixture margin of the Astra Tech Implants Dental System® and the Brånemark System®, whereas the border between the plasma sprayed and the machined surface of the Bonefit®-ITI implant system was positioned at the level of the bone crest. Following a healing period of 3 months, abutment connection was carried out in the 2-stage systems (the Astra Tech Implants Dental System® and the Brånemark system®). A 6-month period of plaque control was initiated. The animals were sacrificed and biopsies representing each implant region dissected. The tissue samples were prepared for light microscopy and exposed to histometric and morphometric measurements. The mucosal barrier which formed to the titanium surface following 1-stage and 2-stage implant installations comprised an epithelial and a connective tissue component, which for the 3 systems studied, had similar dimensions and composition. The amount of lamellar bone contained in the peri-implant region close to the fixture part of the 3-implant systems was almost identical. It is suggested that correctly performed implant installation may ensure proper conditions for both soft and hard tissue healing, and that the geometry of the titanium implant seems to be of limited importance.     

Marginal Bone Resorption at Different Treatment Concepts Using Brånemark Dental Implants in Anterior Mandibles

Background: Different implant treatment modalities, one‐ and two‐step surgery, and one‐step surgery combined with early functional loading have successfully been used in the anterior mandible for rehabilitation of edentulism. However, the marginal bone remodeling has not been compared among the three different techniques. Purpose: The purpose was to compare the marginal bone level in a short‐ and long‐term perspective study using Brånemark dental implants placed according to either a one‐ or a two‐step surgical procedure or a one‐step surgical procedure combined with early functional loading. Materials and Methods: Seven patients were treated with a split‐mouth technique with a one‐step surgical technique on one side and a two‐step technique on the other side. In this latter group, the fixtures were submerged during a 3‐ to 4‐month healing period before abutment connection and loading. In 13 patients, following one‐step surgery, the permanent prosthetic suprastructure was connected within 20 days from implant surgery. All patients were operated on by the same surgeon. The level of the marginal bone was radiographically measured relative to the fixture‐abutment junction and was followed up to 5 years from fixture installation. Results: After connection of the supraconstruction, the marginal bone resorption was significantly lower in the early functional loading group compared to the one‐ and two‐step surgical technique groups. However, after 18 months and after 5 years, the marginal bone was located approximately 1 mm apical to the fixture—abutment level in all three groups. Conclusion: There was no difference in marginal bone resorption in a long‐term perspective between one‐ and two‐step surgical procedures and a one‐step surgical procedure with early functional loading of Brånemark dental implants.     

Effects of Implant Design and Surface on Bone Regeneration and Implant Stability: An Experimental Study in the Dog Mandible

Background: Previous experimental studies have shown a higher degree of bone‐implant contact for surface‐enlarged implants compared with machined implants. Yet, there is insufficient evidence that such implants show higher stability and an increased survival rate. Purpose: The purpose of this investigation was to study the integration and stability of grit‐blasted implants with retention elements on the implant neck, with and without marginal bone defects, compared with machined implants without retention elements. Materials and Methods: After tooth extraction of the mandibular premolars in six dogs, two grit‐blasted, partly microthreaded Astra Tech implants and one standard Branemark implant were bilaterally placed in each dog. On one side, 3 ± 3 mm large buccal defects were created, to expose three to four implant threads. The contralateral side served as control, and no defects were made. The animals were sacrificed after 4 months of healing. Implant stability was measured using resonance frequency analysis at implant installation and after 4 months of healing. Histologic and histomorpho‐metric evaluation was made after 4 months of healing. Results: Resonance frequency analysis indicated that all implants in the test and control groups were osseointegrated after 4 months, with a tendency toward higher implant stability for the Astra Tech implants. There was a statistically significant higher increase in resonance frequency for the Astra test implants compared with their corresponding controls. Histology and histomorphometry showed well‐integrated implants with varying degrees of bone repair at the defect sites. The greater bone‐implant contact for the Astra implants was statistically significant. No significant difference between the implants in amount of bone filling the threads was recorded. Conclusions: The Astra Tech implants tested showed a higher degree of bone—implant contact and higher level of bone regenerated at defect sites compared with the Brånemark implants. Resonance frequency analysis demonstrated a significantly higher increase in the Astra test implants compared with their control groups than did the Brånemark test implants versus their controls.     

A comparative study of the clinical efficacy of Screw Vent irnnlants versus Brånemark fixtures, installed in a periodontal clinic

The clinical success of 85 Screw Vent® and 107 Bråemark® implants, consecutively installed in a private periodontal clinic under the same conditions and by the same operator, is compared. Mobile implants were removed and considered as failures. Intraoral radiographs were assessed for the presence of peri-implant radiolucencies and for analysis of bone loss after functional loading. 85 Screw Vent implants were installed in 31 patients. Of 23 implants installed in 9 mandibles, none failed after 16.8 (range 12–25) months of function. Of 62 Screw Vent implants installed in 23 maxillae, 6 failed at abutment connection, 1 failed after 2 months and 2 after 13 months of function. The absolute failure rate after 13.2 (range 6–24) months was 9162. Mean loss of bone was 1.47 mm (-l.O–+4) after 12 months of functional loading. 107 Brånemark fixtures were installed in 25 patients. Of 51 fixtures inserted in 12 mandibles, none failed; of 56 fixtures installed in 13 maxillae 1 failed before and 2 failed during abutment connection. The absolute failure is 3156. All remaining fixtures were immobile after loading. 13 fixtures were more than 6 months in function. Only short-term comparison between both systems is possible because the observation time is longer for the Screw Vent implants. In the 1st year, only 1 implant system was available to the periodontist. Short-term comparison reveals 11.3% versus 5.3% of cumulative failure after 6 months for the Screw Vent and Brånemark implants, respectively. The results indicate that clinical efficacy is as effectively obtained with Screw Vent as with Brånemark implants in the mandible. The outcome of treatment with Screw Vent implants in the maxilla seems less predictable.     

Brånemark and ITI dental implants in the human bone-grafted maxilla: a comparative evaluation

Abstract: The development of new characteristics concerning implant surface makes it interesting to clinically compare different implant systems in the bone‐grafted maxilla. The aim of this evaluation was to compare clinical data of a two‐staged procedure on the augmented extremely atrophic maxilla using either Brånemark‐ or ITI‐fixures. In 25 patients (18 females, seven males) the severely atrophied maxilla was reconstructed with autogenous iliac or mandibular bone and either Brånemark or ITI implants. Seventy‐eight Brånemark implants and 80 SLA‐ITI implants were inserted in the augmented bone and the patients were followed between 20 and 67 months post implantation. The bone graft was transplanted to add bony volume in the maxillary sinus, the anterior floor of the nose and/or the alveolar ridge. After a healing period of 4½ months, dental implants were inserted and left for healing for 8 months. Twelve consecutive patients received machine‐surfaced Brånemark fixtures and 13 consecutive patients received SLA‐ITI fixtures. Gradual loading was applied after healing abutment application. After 6 months the permanent prosthetic reconstruction was provided to the patient, either as a fixed or removable bridge. Comparison in survival rate was performed: 15 machined Brånemark fixtures were lost, resulting in an overall survival rate of 81%. Two ITI fixtures were lost, resulting in an overall survival rate of 98%. The results of this evaluation show that sandblasted large grit acid etched surface‐treated ITI implants has a significant higher survival rate than machine‐surfaced Brånemark implants in autogenous grafted maxillary bone.     

Influence of the sumastructure on the peri‐implant tissue; in beagle dogs

The purpose of this study was to compare clinical, radiographic and histological differences around titanium oral implants loaded with either acrylic-veneered metal or ceramo-metal fixed prostheses. Five beagle dogs were used in this investigation. At the beginning of the study, all mandibular premolars and first molars were extracted. After 3 months of healing, 2 Brånemark implants were installed on each side of the mandibles. Three months later, abutments were inserted on each implant and a daily oral hygiene regime was initiated. One month after abutment connection, the implants on one side of the mandible were restored with an acrylic-veneered metal fixed prosthesis, whereas, on the other side a ceramo-metal fixed prosthesis was inserted. The prostheses were constructed in occlusion with the maxillary first molars. The following clinical parameters were measured around each implant at this time (i.e., baseline), and thereafter, at monthly intervals up to 5 months: Plaque Index; Gingival Index; implant mobility (using the Periotest®); probing depth and clinical attachment level (using the Florida Probe®). In addition, standardized radiographs were taken at baseline and 5 months after insertion of the prostheses and evaluated by subtraction radiography. Another Brånemark fixture was installed on each side of the mandibles 3 months before the end of the study. These implants remained unloaded and submerged for the entire study period. Five months after prosthesis insertion, the animals were killed, and implants with their supporting peri-implant tissues were processed for histological evaluation. Analyses of the clinical, radiographic and histometric parameters revealed no significant differences between the acrylic-veneered and ceramometal loaded implants. All clinical and radiographic parameters remained stable over time. Histological comparison of the alveolar bone height levels around both loaded groups with those from the unloaded, submerged implants revealed that a similar and slight loss of bone height (approximately 0.6 mm) occurred on the loaded groups following abutment connection. It was concluded that both acrylic-veneered metal and ceramo-metal suprastructures appear to be suitable for the restoration of endosseous oral implants. Additional long-term studies in humans, however, are needed evaluating both types of implant-supported prostheses, in a variety of clinical conditions. before final restorative recommendations are made.     

A three-year follow-up report of a comparative study of ITI Dental Implants and Brånemark System implants in the treatment of the partially edentulous maxilla

Background: Many longitudinal studies of different implant systems have been published but few controlled randomized investigations have been reported. A 1‐year report of a comparative study of ITI Dental Implant System® implants (Straumann AG, Waldenburg, Switzerland) and Brånemark System® implants (Nobel Biocare AB, Gothenburg, Sweden) has been published by the present authors. This paper is a 3‐year follow‐up of that randomized study. Purpose: The aim of the study was to compare the outcome of fixed partial prostheses supported by ITI or Branemark implants. The outcome was evaluated primarily in terms of survival rates and changes in marginal bone level. Material and Methods: The study group comprised 28 patients with anterior residual dentition in the maxilla. The patients were provided with two to four implants on each side of the dentition and were randomly allocated to Brånemark implants or ITI implants; 77 ITI implants and 73 Brånemark implants were inserted. After 6 months abutment connections were made to both ITI and Brånemark implants. All patients were provided with fked partial prostheses of gold‐ceramic. The patients were followed up annually with clinical and radiographic examinations for 3 years. Results: Two Brånemark implants and two ITI implants were lost. The Brånemark implants were lost before loading whereas the ITI implants were lost because of periimplantitis. The survival rate for both groups was 97.3%. The mean marginal bone level of the Brånemark implants was situated 1.8 mm from the reference point at both the baseline and the 3‐year examinations. The corresponding values for the ITI implants were 1.4 mm at baseline and 1.3 mm after 3 years. There was no significant difference between the implant systems with regard to bone level or bone level change. A steady state of the marginal bone level was calculated to have been reached after 3 years for 95.5% of the Brånemark implants and 87.1% of the ITI implants. Periimplantitis (infection including pus and bone loss) was observed with seven ITI implants but with none of the Brånemark implants. This difference was statistically significant. Conclusions: No statistically significant differences were found between the implants studied, except for the frequency of periimplantitis, which was higher for the ITI implants. The survival rates were high, and the marginal bone loss was small for both systems.     

Immediate loading of Brånemark System Implants: a comparison between TiUnite and turned implants placed in the anterior mandible

Purpose: The aim of the present study was to compare the treatment outcome of TiUnite^TM‐ and turned‐surfaced Brånemark System® (Nobel Biocare AB, Göteborg, Sweden) implants when applying immediate loading of cross‐arch designed fixed partial dentures in the anterior mandible. Materials and Methods: Fifteen patients with edentulous mandibles participated in the study. In one half of the jaw, between the exit of the nerve‐vessel bundle and the midline, one type of implant was placed and in the remaining half the other type. The implants were loaded the day of surgery via a fixed, temporary supra‐construction. Ten days later, the permanent one was screw retained to the implant pillars. Results: The present 18‐month clinical trial failed to demonstrate any differences regarding healing and cumulative success rate of an an‐oxidized implant surface (TiUnite) and a turned (turned) one when implants in the anterior mandible were exposed to functional load within 24 hours after installation. Conclusion: A high predictability regarding the treatment outcome for immediately loaded Brånemark implants in the anterior mandible was observed. Furthermore, no difference between the traditional turned and the an‐oxidized implant surface (TiUnite) could be observed. However, it has to be stressed that all implants (irrespective of surface) were placed in the anterior mandible and also that all the patients demonstrated a high level of oral hygiene.     

Bone behavior around sleeping and non-sleeping implants retaining a mandibular hinging overdenture

Since 1984 2 implants in the symphyseal area have been used in our center to retain a hinging overdenture. Because this technique was unknown at that time 1 extra implant was installed in between the 2 others and was left submerged (sleeping). The extra implant served as a rescue implant in case 1 of the 2 others would fail. It was the aim of the present report to compare the marginal bone behavior around those sleeping and non-sleeping implants. Between 1984 and 1987 20 completely edentulous patients were provided with 3 implants (Brånemark system), where from 2 were used to retain a hinging overdenture. Ten years later half of the patients could still be traced. Retroalveolar radiographs were made at the abutment installation and after 10 years. None of the non-sleeping or sleeping implants lost, at an individual basis, more than 1.6 and 0.7 mm of marginal bone respectively. On average, non-sleeping implants lost at the right- and left-hand side of the mandible 0.33 and 0.57 mm of bone respectively. However, sleeping implants lost on average 0.16 mm only. Thus non-sleeping implants lose on average more bone when compared to sleeping implants. Surgical trauma at the abutment connection is believed to be the most plausible cause of marginal bone loss around non-sleeping implants.     

Biologic outcome of single-implant restorations as tooth replacements: a long-term follow-up study

Background: The replacement of a single tooth or several teeth by means of single‐implant restorations is an increasingly used method that needs long‐term validation. Purpose: The goal of this study was to evaluate the outcome of single‐implant restorations by means of fixed restorations and to define the prognosis through marginal bone level estimations. Materials and Methods: From November 1986 to June 1998, 270 Brånemark implants (215 in the upper jaw) were installed in 219 patients (106 males). Both anterior and posterior sites were involved. Of the 263 single restorations, 28 were placed in private dental offices. The patients were followed until June 1999. Results: Twelve implants failed before or at abutment connection or within 6 months afterward. Only four implants failed later. The cumulative success rates were 93% for the implants and 96.5% for the restorations over a period of 11 years. The marginal bone loss during the first 6 months after abutment connection reached 0.71 mm and then dropped to 0.036 mm annually over a period of 10 years. Conclusions: Single‐implant restorations (Brånemark System) are a reliable treatment with a good long‐term prognosis. Failures were concentrated during the healing period and early loading phase.     

One-Year Prospective Evaluation of the Early Loading of Unsplinted Conical Brånemark Fixtures with Mandibular Overdentures Immediately following Surgery

Background: Prospective evaluation of the early loading of unsplinted Branemark implants with mandibular over‐dentures opposing conventional dentures is not evident in the implant‐related literature. Purpose: To clinically evaluate progressive and early loading of 20 unsplinted conical Brånemark implants in edentulous mandibles with overdentures. Materials and Methods: Ten edentulous patients all had two conical Brånemark implants placed in the anterior mandible with mandatory primary stability with bicortical anchorage. Ball abutment connection was performed simultaneously. Previously constructed conventional mandibular dentures were temporarily relined with tissue conditioner postoperatively and worn with moderation for the first 2 weeks to allow progressive loading. Early loading of the implants followed after 2 weeks, with inclusion of the respective matrices in the mandibular dentures, using a definitive reline procedure. Results: All patients successfully functioned with their mandibular implant overdentures from 2 to 52 weeks postoperatively. Mean marginal bone loss was within established criteria for success:0.22 mm (SD = 0.48 mm) mesially and 0.30 mm (SD = 0.39 mm) distally on the conical implants. Mobility tests using the Periotest instrument became more negative, although not at statistically significant levels. Difficulties in the management of the peri‐implant mucosa between surgery and loading at 2 weeks were observed in 40% of the patients. Conclusions: These preliminary 1‐year results show that successful early loading of unsplinted conical Brånemark implants with mandibular overdentures is possible.     

Brånemark System and ITI Dental Implant System for treatment of mandibular edentulism. A comparative randomized study: 3-year follow-up

Abstract: In a randomized prospective study, two implant systems were compared in forty consecutive patients treated for mandibular edentulism. The patients were randomly allotted for treatment by the Brånemark^® two‐stage (submerged) system (BRS), or the ITI^® one‐stage (non‐submerged) system. In all, 102 Brånemark selftapping implants and 106 ITI hollow screw implants were installed and all patients were treated with full bridges. Biological and prosthodontic parameters, complications, success rates, clinical efficacy, patient satisfaction and resource requirements were evaluated. No differences were found in plaque accumulation, bleeding or complications during the follow‐up period. The BRS group showed deeper periimplant sulcus, less attached mucosa, larger bridge‐mucosa distance and higher Periotest values. Prosthetic complications were not related to the configuration of the implant systems. After 3 years, the cumulative success rates were 97.9% and 96.8% for the Brånemark and ITI systems, respectively (difference not statistically significant). One implant in the BRS group had failed to osseointegrate at the time of abutment connection, and another was lost after 2 years due to progressive breakdown of bone. In the ITI group, three implants showed progressive bone loss after 1–3 years associated with periimplant infection. All 40 bridges were intact and remained stable throughout the study. There was general patient satisfaction, but about half the Brånemark patients reported difficulty in coping with the surgical procedures. Treatment time was similar for the two systems. It is concluded that both systems meet the current requirements for dental implant systems in the treatment of mandibular edentulism.     

Implant design and interface force transfer. A photoelastic and strain-gauge analysis

Objectives: To compare stress and strain magnitudes of butt‐joint and internal‐cone oral implants in a bone simulant. Material and methods: Photoelastic and strain‐gauged models of solitary Brånemark^®, ITI^® and Astra Tech^® implants were obtained. Vertical and 20° oblique forces of 100 and 150 N were applied on the abutments in separate load cases. Isochromatic fringe patterns around implants were observed and photographed in the field of a polariscope. Strain‐gauge measurements were performed and principal strains induced around implants were calculated. Results: Isochromatic fringe orders of all designs were similar under both loading conditions (P>0.05). Strains around Brånemark^® implants were lower than around Astra Tech^® and ITI^® implants, particularly under vertical loads. The latter implants had similar strain magnitudes (P>0.05), although strains around the conical Astra Tech^® implant were lower under vertical load. Conclusions: Butt‐joint and internal‐cone oral implants have similar force distribution characteristics. The implant–abutment mating design is not a decisive factor affecting stress and strain magnitudes in a bone simulant.     

The anchorage of Brånemark and ITI implants of different lengths. I. An experimental study in the canine mandible

Abstract: The anchorage of machined Brånemark and ITI TPS‐coated implants of various lengths was investigated in an animal model. Brånemark fixtures 7 and 10 mm long and ITI implants 6 and 10 mm long were inserted in the mandible of dogs and were reverse‐torqued after 3 months of healing. The failing mode was different for the two implant systems. For the ITI implants, loosening coincided with the peak reverse‐torque values. For the Brånemark fixtures, two reverse‐torque values were identified and recorded, a ‘start to rotate’ and a peak value. The ‘start to rotate’ values for the 7 and 10 mm Brånemark fixtures were 36.67 and 38.57 Ncm, respectively, the peak values were 61.88 and 69.13 Ncm. The increase in implant length from 7 to 10 mm did not significantly improve the anchorage. The mean reverse‐torque values for the 6‐ and 10‐mm ITI implants were 104.66 and 192.25 Ncm, respectively; the difference was statistically significant. The mean removal torque of the 6‐mm ITI implant was higher than the 7‐ and 10‐mm Brånemark implants. It is suggested that the distinct anchorage magnitude and the distinct loosening patterns registered for both implant systems might be related to the various surface states. The latter might account for the different failure tendencies mentioned in the literature for short Brånemark and ITI implants.     

Clinical performance of a method for the fabrication of implant-supported precisely fitting titanium frameworks: a retrospective 5- to 8-year clinical follow-up study

Background: The CrescoTi Precision® (CTiP) method (CrescoTi Systems, Lausanne, Switzerland) has been introduced as an alternative method for the fabrication of precisely fitting titanium frameworks. The method is supposed to be used with all major implant systems, without the need for abutments. Purpose: The objectives of this clinical and radiographic retrospective follow‐up study were to report the clinical performances of “CTiP‐fabricated” frameworks that are screw retained directly to Brånemark implants as opposed to Brånemark implant/abutment assemblies (Nobel Biocare AB, Gothenburg, Sweden) and to compare the clinical outcomes of these two modalities. Materials and Methods: Thirty‐six patients were provided with 46 fixed prostheses supported by 207 Brånemark regular‐platform implants. Twenty‐seven prostheses were placed on implant/abutment assemblies, and 19 were placed directly at “implant level.” The prostheses had been in function for 5 to 8 years at the time of the final examinations. Results: Three patients did not attend the final examination. All 43 prostheses in the 33 examined patients were still in function. No major mechanical framework complications were observed during the observation period. One implant was lost after loading. There was no difference in bone loss around the abutment‐free implants when compared with the implants provided with abutments. Conclusions: This long‐term clinical test demonstrated that the CTiP technology constitutes a reliable prosthetic treatment concept in combination with Brånemark implants. The results also revealed that the frameworks could be connected directly to the implants without any negative consequences.     

Immediate Occlusal Loading of Single Lower Molars Using Brånemark System® Wide Platform TiUnite™ Implants: A 5‐Year Follow‐Up Report of a Prospective Clinical Multicenter Study

Introduction: Although not essential, molars hold their importance in terms of functional jaw stability, antagonist opposition, and support of facial height. Therefore, implant therapy is an attractive concept in molar areas. However, especially in the posterior mandible, the conventional two‐stage surgical approach to implant therapy was reported to cause higher bone loss and/or higher implant failures with machined implants because of the peculiar anatomic and physiologic conditions of this area. As the TiUnite? (Nobel Biocare AB, Göteborg, Sweden) surface results in faster bone healing than with machined‐surface implants, it was hypothesized that this surface would also improve the performance of wide implants in posterior mandibles. Based on these assumptions, a protocol for immediately loaded implants for single molar replacement was developed. Purpose: This paper aimed to report on the clinical and radiological performance of Brånemark System® TiUnite Wide Platform implants supporting single molars in the lower jaw, loaded immediately and followed for up to 5 years, and to assess if the benefit delivered by oxidized surfaces in the short run is also present after 5 years. Materials and Methods: The study includes 33 consecutive patients treated between March 2001 and September 2003 and monitored until September 2008 in two private dental offices. A total of 40 Brånemark System TiUnite Wide Platform MK III implants were placed. All implants were provided with provisional crowns in full centric occlusion at the time of surgery. Patients were clinically and radiologically followed up for up to 5 years. Results: Two implant failed so that the cumulative success rate at 5 years was 95.0%. The mean marginal bone remodeling (n = 38) expressed as mesial plus distal value averages was ?1.17 mm (SD ± 0.90) at the 5‐year time point. Conclusion: Although limited by the number of patients treated in accordance with the protocol described, 5‐year results encourage the use of immediately loaded single lower molars supported by Brånemark System Wide Platform TiUnite implants and further document the clinical advantages of titanium oxidized surfaces.