Nobel Biocare AB Research Articles

A Retrospective 5-Year Follow-Up Study of Two Different Titanium Implant Surfaces Used after Interpositional Bone Grafting for Reconstruction of the Atrophic Edentulous Maxilla

Long-term comparative follow-up studies of dental implants placed in augmented bone are rare. Variations in design and surface roughness have been found to be important for bone integration of implants. However, there is no clinical evidence that such variations lead to an improved clinical outcome. To compare two different implant systems used after interpositional bone grafting of the severely resorbed maxilla with a modified augmentation technique using fibrin glue. Twenty-two consecutive patients presenting with severe maxillary atrophy underwent reconstruction with Le Fort I osteotomies and interpositional bone grafting. Before placement of bone blocks, the floors of the maxillary sinuses were packed with bone chips mixed with a fibrin glue, to stabilize the graft. After 6 months of graft healing, the first 11 consecutive patients received Brånemark System implants with a turned surface (Nobel Biocare AB, Göteborg, Sweden). The following 11 consecutive patients were treated with Astra Tech implants with a blasted titanium surface (Astra Tech AB, Mölndal, Sweden). All patients received fixed prostheses. Marginal bone resorption and donor and recipient site morbidity were evaluated. All patients were clinically and radiographically observed throughout 5 years of functional loading. In the Brånemark group, 11 (13%) of 84 placed implants were lost, compared to 4 (5.5%) of 72 placed implants in the Astra Tech group. The difference was not significant. All patients retained fixed constructions after 5 years of loading. The mean marginal bone loss was 2.3+/-0.8 mm (range, 0-5.0 mm) in the Brånemark group and 2.4+/-1.4 mm (range, 0-7.0 mm) in the Astra Tech group although again no statistical difference was found. A larger number of implants in the Astra Tech group had a marginal bone resorption of>or=3 mm, and implant success in that group was lower than in the Brånemark group (52% vs 70%). In this study, reconstruction of the severely resorbed maxilla with Le Fort I osteotomy, interpositional bone grafting, and delayed placement of dental implants was found to be a predictable long-term procedure. Although more implants with a turned surface were lost during the follow-up period, there were no statistically significant differences between turned and titanium blasted implants.

Short Implants in the Severely Resorbed Maxilla: A 2‐Year Retrospective Clinical Study

Although the predictability of endosseous dental implants is well documented, the restoration of the posterior region of the maxilla remains a challenge. The placement of short implants is one therapeutic option that reduces the need for augmentation therapy. The purpose of this retrospective study was to assess the survival rates of 6 to 8.5 mm-long implants in the severely resorbed maxilla following a surgical protocol for optimized initial implant stability. The study included 85 patients with 96 short (6-8.5 mm) implants (Brånemark System, Nobel Biocare AB, Göteborg, Sweden) supporting single-tooth and partial reconstructions. The implants had a machined (54) or an oxidized (TiUnite, Nobel Biocare AB) (42) surface. A one-stage surgical protocol with delayed loading was used. The patients were followed for at least 2 years after loading (average follow-up period 37.6 months). The marginal bone resorption was assessed by radiographic readings. Five implants were lost during the first 9 months, and four implants were lost to follow-up. The cumulative survival rate was 94.6%. Four of the failed implants had a machined surface, and one had an oxidized surface. The mean marginal bone resorption after 2 years in function was 0.44 +/- 0.52 mm. This study demonstrates that the use of short implants may be considered for prosthetic rehabilitation of the severely resorbed maxilla as an alternative to more complicated surgical techniques.

Direct Implant Loading in the Edentulous Maxilla Using a Bone Density–Adapted Surgical Protocol and Primary Implant Stability Criteria for Inclusion

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. 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. 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. 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. 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.

All‐on‐4 Immediate‐Function Concept with Brånemark System® Implants for Completely Edentulous Maxillae: A 1‐Year Retrospective Clinical Study

Immediate implant function has become an accepted treatment modality for fixed restorations in totally edentulous mandibles, whereas experience from immediate function in the edentulous maxilla is limited. The purpose of this study was to evaluate a protocol for immediate function (within 3 hours) of four implants (All-on-4, Nobel Biocare AB, Göteborg, Sweden) supporting a fixed prosthesis in the completely edentulous maxilla. This retrospective clinical study included 32 patients with 128 immediately loaded implants (Brånemark System TiUnite, Nobel Biocare AB) supporting fixed complete-arch maxillary all-acrylic prostheses. A specially designed surgical guide was used to facilitate implant positioning and tilting of the posterior implants to achieve good bone anchorage and large interimplant distance for good prosthetic support. Follow-up examinations were performed at 6 and 12 months. Radiographic assessment of the marginal bone level was performed after 1 year in function. Three immediately loaded implants were lost in three patients, giving a 1-year cumulative survival rate of 97.6%. The marginal bone level was, on average, 0.9 mm (SD 1.0 mm) from the implant/abutment junction after 1 year. The high cumulative implant survival rate indicates that the immediate function concept for completely edentulous maxillae may be a viable concept.

Early Loading of Interforaminal Implants Immediately Installed after Extraction of Teeth Presenting Endodontic and Periodontal Lesions

Infection in tooth extraction sites has traditionally been considered an indication to postpone implant insertion until the infection has been resolved. The aim of this study was to evaluate the survival rate of early-loaded implants placed immediately after extraction of teeth with endodontic and periodontal lesions in the mandible. Twenty patients in need of mandibular implant treatment and with teeth showing signs of infection in the interforaminal area were included in the study. The patients received four to six implants (Brånemark System, Nobel Biocare AB, Göteborg, Sweden) in or close to the fresh extraction sockets and received a provisional prosthesis within 3 days. Final prostheses were delivered after 3 to 12 months. The surgical protocol paid special attention to the preservation of high implant stability and control of the inflammatory response. The patients were followed up for 15 to 44 months. No implants were lost, resulting in a 100% survival rate. A mean marginal bone loss of 0.7 mm (SD 1.2 mm) was registered during the observation period. No signs of infection around the implants were detected at any follow-up visit. A high survival rate can be achieved for immediately placed and early-loaded implants in the mandible despite the presence of infection at the extracted teeth.

A Computed Tomographic Scan–Derived Customized Surgical Template and Fixed Prosthesis for Flapless Surgery and Immediate Loading of Implants in Fully Edentulous Maxillae: A Prospective Multicenter Study

Based on three-dimensional implant planning software for computed tomographic (CT) scan data, customized surgical templates and final dental prostheses could be designed to ensure high precision transfer of the implant treatment planning to the operative field and an immediate rigid splinting of the installed implants, respectively. The aim of the present study was to (1) evaluate a concept including a treatment planning procedure based on CT scan images and a prefabricated fixed prosthetic reconstruction for immediate function in upper jaws using a flapless surgical technique and (2) validate the universality of this concept in a prospective multicenter clinical study. Twenty-seven consecutive patients with edentulous maxillae were included. Treatments were performed according to the Teeth-in-an-Hour concept (Nobel Biocare AB, Göteborg, Sweden), which includes a CT scan-derived customized surgical template for flapless surgery and a prefabricated prosthetic suprastructure. All patients received their final prosthetic restoration immediately after implant placement, that is, both the surgery and the prosthesis insertion were completed within approximately 1 hour. In the 24 patients followed for 1 year, all prostheses and individual implants were recorded as stable. The present prospective multicenter study indicates that the prefabrication, on the basis of models derived from three-dimensional oral implant planning software, of both surgical templates for flapless surgery and dental prostheses for immediate loading is a very reliable treatment option. It is evident that the same approach could be used for staged surgery and in partial edentulism.

The Human Bone–Oxidized Titanium Implant Interface: A Light Microscopic, Scanning Electron Microscopic, Back‐Scatter Scanning Electron Microscopic, and Energy‐Dispersive X‐Ray Study of Clinically Retrieved Dental Implants

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. 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. 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. 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 microm). 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.

Immediate/Early Function of Brånemark System® TiUnite™ Implants in Fresh Extraction Sockets in Maxillae and Posterior Mandibles: An 18‐Month Prospective Clinical Study

The advantages of placing implants in fresh extraction sockets and putting them in immediate/early function are many. A predicable protocol opens the possibility of performing a single surgical procedure, giving the patient a temporary prosthesis immediately, and minimizing the shrinkage of hard tissue and soft tissue recession. The aim of the present study was to develop a strict protocol for and to evaluate the feasibility of immediate/ early function on implants placed in fresh extraction sockets located in maxillae and posterior mandibles, including defects around the implants treated according to a regenerative procedure. Nineteen patients were treated after tooth extraction according to an immediate function protocol and were observed for 18 months. Fifty Mk IV TiUnite (Nobel Biocare AB, Göteborg, Sweden) implants were installed in partially edentulous areas in maxillae (n = 17) and posterior mandibles (n = 5). Implants were installed directly into the alveoli, and the temporary prostheses were connected immediately after surgery (n = 11) or within 7 days, that is, an "early function" procedure (n = 11). Thirteen implants did not require any type of regenerative procedure, whereas the remaining 37 implants had filling with autogenous bone, 4 of which also had a resorbable membrane. Standardized intraoral radiographs were taken for evaluation of marginal bone level, and 38 of the implants were systematically checked by resonance frequency analysis. All patients were followed for 18 months, and none of the 50 implants failed. However, one implant showed signs of failure after 6 weeks, but once the occlusal load was removed, the implant regained its stability completely, no longer demonstrated symptoms, and could be used successfully for prosthetic rehabilitation. The mean value of the implant stability quotient was 60 at baseline (range 45-75) and 63 after 6 months (range 46-75). The marginal bone resorption was 0.9 mm (SD 1.1 mm; n = 48) 18 months after implant insertion (1 year after final prosthesis). The immediate placement of implants into fresh extraction sockets combined with immediate/early function procedures seems to be a safe and reliable procedure when using a strict protocol.

Immediate Occlusal Loading of Brånemark System® TiUnite™ Implants Placed Predominantly in Soft Bone: 4‐Year Results of a Prospective Clinical Study

Immediate occlusal implant loading has been documented as a viable treatment option for various indications. However, most of the available studies reported on the short-term outcome of this treatment modality. The purpose of this prospective clinical study was to document, on a long-term basis, the outcome of immediate occlusally loaded Brånemark System Mk IV TiUnite (Nobel Biocare AB, Göteborg, Sweden) implants placed to support fixed reconstructions in various regions of the jaws. Thirty-eight patients received a total of 51 fixed prosthetic reconstructions, all of which were connected on the day of implant insertion. Twenty restorations replaced single teeth, 30 were fixed partial dentures, and 1 was a full-arch fixed lower restoration. These prostheses were supported by 102 Brånemark System Mk IV TiUnite implants (38 maxillary and 64 mandibular), the majority of which were placed in posterior regions (88%) and mainly in soft bone (76%). Resonance frequency measurements and marginal periimplant soft tissue evaluations were conducted during the course of the study. Furthermore, radiographic examinations were performed at the time of prosthesis delivery and at the 1- and 6-month and 1-, 2-, 3-, and 4-year follow-up visits. This report summarizes the results after 4 years of loading. Three maxillary implants were removed, although stable, in one patient at the 8-week follow-up owing to postoperative infection in the adjacent guided bone regeneration area. No implants were lost further on. This resulted in a cumulative implant success rate of 97.1% after 4 years of prosthetic loading. The mean marginal bone remodeling after 4 years of function was 1.3 +/- SD 0.9 mm. At 4 years, absence of marginal plaque and bleeding on probing was reported for 87% and 69% of the sites, respectively, thereby remaining unchanged since the 1-year follow-up. On average, the interproximal soft tissue fill increased for both mesial and distal papillae from scores of 1.4 +/- 1.1 and 1.0 +/- 1.1, respectively, at the preoperative assessment to 2.0 +/- 0.8 and 1.7 +/- 0.8, respectively, at the 4-year assessment. The applied immediate loading protocol, in combination with a slightly tapered implant design and a modified implant surface texture, was shown to be a successful treatment alternative in regions exhibiting soft bone.

One‐Year Results of a Prospective Multicenter Study on Brånemark System® Implants with a TiUnite™ Surface

A moderately rough surface implant (TiUnite, Nobel Biocare AB, Göteborg, Sweden) was introduced in 2000. Laboratory studies and some clinical studies have demonstrated excellent bone response in the early healing phase. The aim of this prospective multicenter study was to follow a large number of consecutively treated patients using Brånemark System implants with the TiUnite surface. The current report constitutes the 1-year data of a planned 3-year study. Originally, the study comprised 43 surgeons from 22 centers in Sweden, Norway, and Finland. Five centers were excluded from the study because of poor compliance. Thus, 187 patients treated with 478 TiUnite implants were followed during 1 year of function. The majority of implants were inserted in maxillae (357 implants), and 78 of the implant sites were assigned the quality 4 figure. Radiographic evaluations were performed. Five implants were lost up to and including the 1-year follow-up, revealing implant cumulative survival rates of 98.6% and 100% for maxillae and mandibles, respectively. Three implants failed in quality 4 bone (3.8%). The mean marginal bone resorption at the end of the study period was 1.4 mm. The number of withdrawals of patients during the first year was high (19.3%). The present investigation showed a high implant cumulative survival rate of 98.9%. Values of marginal bone resorption were within normal ranges. No adverse effects of the TiUnite surface were reported, and complications during the study period were few and similar to those reported for the turned implant surface. However, the high number of excluded patients and the relatively high number of withdrawals must be observed and considered when interpreting data.

Retrospective Clinical Evaluation of 86 Procera AllCeram™ Anterior Single Crowns on Natural and Implant‐Supported Abutments

The Procera AllCeram (Nobel Biocare AB, Göteborg, Sweden, and Procera Sandvik AB, Stockholm, Sweden) technique is one alternative to metal-ceramic restorations. However, few long-term evaluations of its use for single crowns on natural and implant-supported abutments are available. The aim of the present study was to assess the clinical performance of Procera AllCeram single crowns when placed in aesthetic sites supported by either natural teeth or implants over a period of 48 months. Eighty-six single crowns were fabricated and used in 51 patients. The restorations were examined according to the California Dental Association's quality assessment system. One crown was lost after 20 months of follow-up. Of the 85 restorations that completed the 48-month follow-up, only one crown (1.2%) showed a veneering porcelain chip. All crowns were ranked as either excellent or acceptable. The success rates of single crowns supported by natural tooth and implant-supported abutments were 100% and 98.3%, respectively; the total crown success rate was 98.8%. Within the limitations of the present study, Procera AllCeram crowns proved to be a reliable therapeutic choice for the restoration of anterior teeth on both natural and implant-supported abutments. The hybrid glass-ionomer cement used in the present study appeared to be a reliable luting agent.

Oxidized Titanium Implants in Reconstructive Jaw Surgery

Rehabilitation with implant-supported bridges in patients with insufficient bone volumes may require bone reconstructive procedures in conjunction with or prior to implant placement. Clinical follow-up studies using turned titanium and bone grafts have demonstrated higher failure rates than when used in nongrafted patients. Improved bone integration has been demonstrated for oxidized titanium implants; however, their clinical performance in bone reconstruction situations is not known. This study was performed to analyze the survival and stability of oxidized titanium implants placed in patients subjected to reconstructive jaw surgery at one clinic. Two hundred oxidized titanium implants (Mk III, TiUnite, Nobel Biocare AB, Göteborg, Sweden) were placed in 47 patients in conjunction with or secondary to six different reconstructive procedures owing to insufficient bone volume. In all six groups, implant stability was assessed by resonance frequency analysis and manually checked for rotation stability at implant insertion, at the time of abutment connection, and after a minimum of 12 months of loading of the prosthetic construction. Periapical radiographs were taken after a minimum of 12 months of loading (mean 21 months) for evaluation of the marginal bone levels. The mean clinical follow-up period was 30 months. Of the 200 implants, 199 were considered osseointegrated at the time of abutment surgery. At the 12-month postloading follow-up, another two implants were considered not stable. Three implants (1.5%) were ranked as unsuccessful. Clinical experience with 200 consecutive oxidized implants in various reconstruction situations shows a successful outcome, with only three failures (1.5%) during a mean follow-up period of 30 months.

Simplified Methods of Implant Treatment in the Edentulous Lower Jaw: A 3‐Year Follow‐Up Report of a Controlled Prospective Study of One‐Stage versus Two‐Stage Surgery and Early Loading

Interest in the use of one-stage surgery and immediate loading of oral implants has lately been increasing. The aim of this study was to compare the 3-year results of one-stage surgery versus two-stage surgery, early loading versus loading after a 3-month healing period, and the use of one-piece implants versus the use of two-piece implants. The study included 108 patients with edentulous mandibles. Each patient was treated with four Brånemark System implants (Nobel Biocare AB, Göteborg, Sweden) and with full fixed prostheses. Patients were consecutively treated and were distributed in four groups: group A (one-stage surgery), group B (control group with two-stage surgery), group C (one-piece implants), and group D (early loading). In groups A and B Brånemark Standard implants and standard abutments were used. In group C the conical one-piece Brånemark implant was used, and in group D the patients had Brånemark System Mk III implants together with multiunit abutments. All patients were observed for 3 years. Of the 432 inserted implants, 24 were lost. Survival rates in the three experimental groups ranged from 93.2 to 93.3% whereas the survival rate in group B (the control group with two-stage surgery) was 97.5%. The differences between the groups were not statistically significant. The changes in marginal bone level were measured from fixture insertion to the final follow-up at 3 years. The bone loss in group D (early loading) was significantly less than in group B (the control group) whereas there were no differences in marginal bone change between the other groups. Early loading seemed to give good results in the anterior part of the mandible. The survival rate of the early-loaded implants did not significantly differ from that of implants inserted with the conventional two-stage procedure, but the mean marginal bone loss around the surviving implants was less with early loading.

Microbiological and clinical outcomes and patient satisfaction for two treatment options in the edentulous lower jaw after 10 years of function

Long-term data on microbiological and clinical outcome as well as on patient satisfaction after implant therapy in the edentulous mandible are limited. Especially comparisons between fixed full prostheses (FFPs) and overdentures (ODs), or between anchoring systems for the latter are scarce. This study aimed to evaluate both of these parameters at the 10-year follow-up in a group of fully edentulous patients rehabilitated via an OD or a FFP (the latter to allow inter-group comparison). A total of 37 fully edentulous patients (25 ODs, 12 FFPs, age at implant installation ranged from 36 to 85 years) participated in this study. All subjects received their implants (Branemark System, Nobel Biocare AB, Gothenburg, Sweden) 10 years previously. For the ODs different attachment systems (bar, magnets, ball) had been applied that allowed a further intra-group comparison. At the follow-up visit, 10 years after the abutment insertion, a series of periodontal parameters were recorded, long-cone radiographs were taken and subgingival plaque samples were collected for analysis using checkerboard DNA-DNA hybridization. The clinical and radiographic data were recorded at abutment connection and after 1 and 10 years. After 10 years of loading, mean plaque and bleeding indices and changes in attachment or marginal bone level were not significantly different, neither between the OD and FFP group, nor within the OD group. The marginal bone loss between abutment connection and year 10 was 0.86 and 0.73 mm for OD and FFP groups, respectively. The subgingival microbiota at implant sites from all (sub)-groups was comparable, with low numbers of DNA counts (+/-10 x 10(5)) but high detection frequencies of Actinobacillus actinomycetemcomitans (>90%), Porphyromonas gingivalis (>85%) and Tannerella forsythensis (30%). The composition of the subgingival microbiota was influenced by probing depth and bleeding tendency. Patient satisfaction was very high for both types of prosthetic rehabilitation. The FFP group scored only slightly better for chewing comfort and general satisfaction. These data indicate that from the clinical and microbiological standpoint, as well as patient satisfaction, both an OD and a FFP offer a favourable long-term outcome.

Measurements of Soft Tissue Volume in Association with Single‐Implant Restorations: A 1‐Year Comparative Study after Abutment Connection Surgery

Patients with buccal defects due to tooth extraction seem to regain some of the contour at the time of abutment surgery and connection of single-implant crown restorations. It can then be assumed that different abutment systems could restore the buccal contour to different degrees. To measure changes in buccal tissue volume after placing restorations with single-implant crowns using two different abutment systems and to measure soft tissue change during the 1 year after single-implant treatment. Eighteen patients were provided with single-implant restorations in the central incisor area. Nine patients in each group were treated with single-implant crowns supported by either CeraOne abutments (Nobel Biocare AB, Göteborg, Sweden) or customized Procera ceramic abutments (Nobel Biocare AB). Study casts were made before abutment connection, at crown placement, and after 1 year. After the casts were scanned, they were analyzed with a computer, using the model before abutment as a reference. In the area of the single implant, sagittal projections provided images of the models that allowed measurements between the contours at the different situations. Radiography and photography for measuring papillary volume were also performed. All patients exhibited increased "buccal volume" after abutment connection and crown placement (p < .01). A trend to greater increase was observed for the Procera group. Both groups also showed a reduction of buccal tissue 1 year later (p < .05-.01), leaving on average more volume in the Procera group. The papillae recovered spontaneously, and no relationship was observed between the presence of papilla and underlying bone support (p > .05). The buccal tissue increased significantly after placement of the abutment cylinder and the implant crown. This increase of buccal contour was reduced after 1 year. Furthermore, no relationship was established between the presence of papillae and the distance between the contact point and the underlying bone crest.

Fixed Implant‐Supported Prostheses in Elderly Patients: A 5‐Year Retrospective Study of 133 Edentulous Patients Older than 79 Years

An increasing number of elderly patients are treated with implants, but results for the elderly patient in terms of implant success and adaptation to implant prostheses are contradictory. To retrospectively study the 5-year clinical and radiologic performances of fixed implant-supported prostheses placed in edentulous elderly patients and to compare those results with the results of using similar prostheses in a control group of younger patients. The study group comprised 133 edentulous patients who were 80 or more years of age and who were consecutively treated with fixed implant-supported prostheses between January 1986 and August 1998. Altogether 761 Brånemark System implants (Nobel Biocare AB, Göteborg, Sweden) were placed in 139 edentulous jaws. The control group comprised 115 edentulous patients who were younger than 80 years and who were treated consecutively from March 1996 to November 1997 with similar prostheses. In this group 670 implants were placed in 118 edentulous jaws. Information was collected from all postinsertion visits, including the fifth annual checkup, and changes of marginal bone levels were analyzed from intraoral radiographs. The 5-year cumulative survival rate (CSR) for implants in the maxilla was 93.0% in the study group and 92.6% in the control group; the corresponding CSRs for implants in the mandible were 99.5% and 99.7%. The most common complications for patients in the study group were soft tissue inflammation (mucositis) and cheek and lip biting (p < .05) whereas resin veneer fractures were the most common complications for the control group. Overall 5-year marginal bone loss for the study group was 0.7 mm (standard deviation [SD], 0.45) in the upper jaw and 0.6 mm (SD, 0.50) in the lower jaw. Differences in bone levels and bone loss between the two groups did not reach significant levels (p > .05). Implant treatment in the elderly patients showed treatment results comparable to those observed in younger age groups. However, indications of more problems with adaptation could be observed and were reflected in more postinsertion problems. Cleaning problems and associated soft tissue inflammation (mucositis) as well as tongue, lip, and cheek biting were significantly more often observed among the elderly patients (p < .05).

A Surgical Stent for the Brånemark Novum® Bone Reduction Procedure

The Brånemark Novum concept (Nobel Biocare AB, Göteborg, Sweden) was introduced to load implants immediately with a definitive fixed prosthesis in the edentulous mandible. This concept is based on the use of prefabricated templates to allow precise placement of three implants and a prefabricated bar structure for the prosthetic procedure. To obtain three-dimensional stability in these prefabricated templates, surgical bone reduction may be necessary to obtain a stable adaptation between the templates and the recipient bone site. The aim of this work was to design a surgical stent for predictable reduction of the residual alveolar crest prior to the implant placement procedures. A predetermined alveolar crest platform based essentially on a lateral cephalometric radiographic evaluation was simulated on a cast in order to design a transparent resin surgical guide. The predictability potential of the procedure was then evaluated in 10 patients. The prosthetic outcomes were compared with those of a similar group of 10 patients treated without the presented stent by evaluating two factors, namely, the anterior dimensions of the prostheses and the required posterior adjustments of the upper bar. Correlation analysis of our series suggested a good predictability potential for this procedure (r = 0.9215). The mean anterior prosthetic dimension was 32% lower and was more predictable (narrow range of 8-12 mm vs broad range of 8-21 mm) when the stent was used. Furthermore, since half as many posterior adjustments of the upper bar were required, the laboratory procedure was facilitated. This individualized guide allows appropriate bone reduction for obtaining a predictable surgery and prosthetic stage.

Stability of the Implant/Abutment Joint in a Single‐Tooth External‐Hexagon Implant System: Clinical and Mechanical Review

Rigorous efforts have recently been made to reduce the recurrence of implant/abutment joint failure in single-tooth implant restorations. However, the current knowledge about the stability of implant/abutment joints in an external hexagon implant system is incomplete. We reviewed clinical data regarding single-tooth implant treatment with Brånemark implants, specifically the CeraOne abutment system (Nobel Biocare AB, Göteborg, Sweden). In vitro studies on joint stability were systematically assessed. Bending overload and the presence of misfit at the implant/abutment joint interface are the critical mechanical conditions that can make the joint unstable. Appropriate joint fitness and proper alignment of the implant should be assessed, and occlusal adjustment by narrowing the restoration width and flattening cuspal inclination should be applied to avoid bending moments caused by the lateral component of occlusal forces. Sufficient clinical reports of longer duration that evaluate and verify longer-term success of the newly manufactured joint components were unavailable.

Abutment Screw Loosening and Bending Resistance of External Hexagon Implant System after Lateral Cyclic Loading

Rigorous efforts to reduce the recurrence of abutment screw loosening in single-tooth implant restorations have recently been made. However, the behavior of the implant/abutment joint components with respect to critical bending force is still unclear. This study investigated the effect of different cyclic loading periods on abutment screw loosening and bending resistance of a single-tooth external hexagon implant system. Fifteen Brånemark implant assemblies were divided equally into groups A, B, and C. Each assembly consisted of a Brånemark System Mk IV 4 x 10 mm implant (Nobel Biocare AB, Gothenburg, Sweden) mounted in a brass block, a CeraOne 3 mm abutment (Nobel Biocare AB), and an experimental cement-retained superstructure. For groups A and B a cyclic load of 50 N was applied centrally and perpendicular to the long axis of the implant. Targets of 1.0 x 10(6) cycles (40 months of simulated function) and 0.5 x 10(6) cycles (20 months of simulated function) were defined for groups A and B, respectively. Group C (control) was left unloaded for the same loading time period as was group B. Reverse torque was recorded before and after loading, and the difference was calculated. After cyclic loading, specimens were mounted in a testing machine, and the yielding and bending strengths were measured. The data were analyzed with one-way analysis of variance and were compared by means of the Tukey test (p < .05). There were statistically significant differences (p < .001) in the reverse torque difference values of group A ([-5.6 to -3.4] +/- 0.86 Ncm) as compared to those of group B ([-2.4 to -1.6] +/- 0.32 Ncm) and group C ([-0.7 to 0.0] +/- 0.26 Ncm). Likewise, group B showed a significant difference compared to group C (p = .002). On the other hand there was no statistically significant difference in the mean values among the test groups in regard to the yielding and bending strengths (p >.050). Within the limitations of this study, long-term fatigue significantly affected the reverse torque values under centric lateral load (p <.001) whereas it had no significant effect on the resistance of the implant/abutment joint to static bending.

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

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. 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. 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. 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. 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.