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PubMed2004

A 5-year prospective study of single-tooth replacements supported by the Astra Tech implant: a pilot study.

BACKGROUND: Implant-supported single-tooth replacements are an increasingly used method to replace teeth, especially in young patients. Therefore, long-term validation of different treatment modalities with different implant systems is of great importance. PURPOSE: The aim of the present study was to make a biologic, technical, and aesthetic evaluation of single-tooth replacement supported by the Astra Tech implant (Astra Tech AB, Mölndal, Sweden) during a 5-year period. MATERIALS AND METHODS: Twenty patients were divided into two consecutively treated groups. In group A the implants were placed "early" in the extraction sockets, and standard single-tooth abutments were used. In group B the implants were placed "delayed," and preparable abutments were used. Clinical examinations including registration of plaque, bleeding, crown lengths, soft tissue marginal level, papilla height, complications, and radiography were performed yearly. At the 3-year control examination the patient and a dentist evaluated aesthetic appearance with a visual analog scale. RESULTS: An implant survival rate of 100% and a crown survival rate of 95% over a period of 5 years were found. The mean loss of marginal bone adjacent to implants and neighboring teeth was less than 0.5 mm during the 5-year period, and there was no significant difference after crown placement between the treatment modality for group A and that for B. There were fewer clinical complications and repairs in group B than in group A. Soft tissue dimensions were more natural around implant crowns in group B as compared to group A, but this was not reflected in the patients' satisfaction with aesthetic appearance. On the other hand the dentist judged the restorations in group B higher concerning aesthetics than in group A. CONCLUSION: Implant-supported single-tooth replacement with the Astra Tech system is a reliable treatment resulting in a good 5-year prognosis and only few complications.

Adolescent↗
PubMed2004

Implant stability, tissue conditions, and patient self-evaluation after treatment with osseointegrated implants in the posterior mandible.

BACKGROUND: Implant treatment in the posterior mandible is considered challenging because of bone resorption and the presence of the inferior alveolar nerve, which may result in the use of short implants. PURPOSE: To evaluate implant stability, tissue conditions, and patient opinion after treatment with implant-supported bridges in the posterior mandible. MATERIALS AND METHODS: Thirty-four patients treated with implant-supported bridges in the posterior mandible according to a two-stage protocol were clinically and radiographically examined and interviewed after a mean functional time of 3.9 years. One hundred five Brånemark implants (Nobel Biocare AB, Gothenburg, Sweden) were placed in premolar and molar regions to support 40 bridges. Twenty-eight implants were placed anterior to the mental foramen, and 77 implants were placed posterior to the mental foramen. Bridges were supported either by two or by three implants. After 2 to 6 years, the bridges were removed to analyze the resonance frequency of the implants with the use of a special instrument (Osstell instrument, Integration Diagnostics AB, Gothenburg, Sweden), and an implant stability quotient (ISQ) was recorded for each implant. RESULTS: One implant was lost. An ISQ range of 59 to 90 (mean, 70.05) expressed stability of fully integrated implants in the posterior mandible. Significantly higher (p < .024) ISQ values were found in implants in three-implant bridges when compared with implants in two-implant bridges. There were no differences in ISQ values between molars/premolars, implant types, implant widths, implant lengths, anchoring depth, or uni- or bilateral mandibular bridges. Good mucosal health in the periimplant soft tissue and minor bone resorption around the implants were observed. Patients were generally very satisfied with the treatment outcome. CONCLUSIONS: High implant stability can be reached in the posterior mandible. The implants were more stable in three-implant bridges than in two-implant bridges. The patients were highly satisfied with the treatment, and few complications were seen.

Aged↗
PubMed2004

Some biomechanical and histologic characteristics of early-loaded locking pin and expandable implants: a pilot histologic canine study.

BACKGROUND: A two-stage approach with a 3- to 6-month healing period is recommended for the "conventional" osseointegration technique with oral implants. This may induce inconvenience and discomfort for patients, and immediate early loading protocols are preferable. PURPOSE: To compare a new type of implant with two locking pins, designed to allow immediate loading, with an expandable implant design with regard to bone tissue response and implant stability. MATERIALS AND METHODS: The molars and premolars of two beagle dogs were extracted in the mandible, and two types of implants (an apically expandable implant and a locking pin implant) were immediately placed in the sockets. The dogs received at least four implants (two of each type) in each side of the mandible. Implants were loaded with gold-palladium bridges 15 days later. The loaded implants were left for 3 months, and the dogs were sacrificed. Resonance frequency analysis (RFA) was performed at placement and sacrifice. Ground sections for histomorphometry were produced for each implant. RESULTS: Implant stability as measured by RFA was similar for the two types of implants before healing. At termination of the study, stability was higher for the locking pin implants. Bone histomorphometry showed that both types of implant were anchored by the same amount of bone and that bone-titanium interfaces did not differ. CONCLUSION: The locking pin implant showed better secondary stability than did the expandable implant, probably because of a better transmission of strains to bone.

Animals↗
PubMed2004

One-stage surgery and early loading of three implants for maxillary overdentures: a 1-year report.

BACKGROUND: Maxillary implant overdentures opposing mandibular two-implant overdentures are an underused treatment option for edentulous patients. Fewer implants, simple surgery, and short healing periods may increase patients' acceptance of this treatment concept. PURPOSE: To determine implant success, after overdenture loading, of three narrow-diameter roughened-surface implants placed in edentulous maxillas, using a one-stage surgical procedure, a 12-week healing period, and opposing mandibular two-implant overdentures. MATERIALS AND METHODS: Forty edentulous participants with mandibular two-implant overdentures were allocated to two groups with similar implant systems. Each group had three narrow-diameter roughened-surface implants placed into their edentulous maxillas in a one-stage surgical procedure. Standardized intraoral radiography and implant stability tests were performed sequentially at surgery, at 12 weeks (prior to loading), and at 64 weeks (after 1 year of loading with maxillary overdentures). RESULTS: One hundred seventeen implants were placed in 39 participants. After 1 year of loading, 15 implants had failed in 11 patients, 4 implants have been "put to sleep" in 3 patients, and 1 patient has died. Data on marginal bone loss and resonance frequency analysis showed no significant differences between the implant systems. The mean marginal bone loss was 1.30 mm (+/- 0.44 mm) from surgery to 12 weeks and 0.32 mm (+/- 0.48 mm) between 12 and 64 weeks with loading. The mean implant stability quotient and resonance frequency values showed a statistically significant improvement over time, at 56.05 (5,891 Hz), 57.54 (5,981 Hz), and 60.88 (6,167 Hz) at surgery, 12 weeks, and 64 weeks, respectively. The overall success rate for all implants combined was 81%, and the cumulative survival rate was 84.61%. CONCLUSION: In patients with mandibular two-implant overdentures, three narrow-diameter roughened-surface implants can be placed in the edentulous maxilla, using a one-stage surgical procedure, and can be loaded within 12 weeks with overdentures for 1 year.

Aged↗
PubMed2004

Clinical experiences of computer numeric control-milled titanium frameworks supported by implants in the edentulous jaw: a 5-year prospective study.

BACKGROUND: Few long-term follow-up studies on treatment concepts using computer numeric control-milled titanium frameworks have been conducted. OBJECTIVE: To evaluate the clinical and radiographic performance of implant-supported prostheses provided with computer numeric control-milled titanium frameworks in the edentulous jaw and to compare their performance during the first 5 years of function with that of prostheses provided with conventional cast gold alloy frameworks. MATERIALS AND METHODS: A consecutive group of 126 edentulous patients were randomly provided with 67 prostheses with titanium frameworks (test group) in 23 upper jaws and 44 lower jaws and with 62 conventional prostheses with gold alloy castings (control group) in 31 upper jaws and 31 lower jaws. Clinical and radiographic 5-year data were collected for the test and control groups. RESULTS: The frequency of problems was low, and clinical and radiologic performances were similar in both groups. In the test group, the 5-year cumulative survival rates (CSRs) were 94.9% and 98.3% for implants and titanium prostheses, respectively. The respective corresponding CSRs for the control group were 97.9% and 98.2%. More loaded implants were lost in the maxillas in the test group (p < .01), but this difference was not significant on the patient/prosthesis level (p > .05). Smokers lost more implants than nonsmokers lost (p < .01). Similar survival rates were observed for implants in the mandible. One prosthesis was lost in each group because of the loss of implants. Metal fractures were seen only in the control group, and resin veneer fractures were more frequent in the maxilla in the gold alloy group (p < .05). In the test group, the mean marginal bone loss was 0.5 mm (SD, 0.44) in the maxilla and 0.4 mm (SD, 0.50) in the mandible. A similar pattern of bone reaction was observed in the control group. Mean marginal bone loss was similar for smokers and nonsmokers (p > .05). CONCLUSION: Computer numeric control-milled titanium frameworks are a viable alternative to gold alloy castings in the edentulous jaw and present clinical and radiologic performances similar to those of conventional gold alloy frameworks during the first 5 years of function.

Aged↗
PubMed2004

Early function of splinted implants in maxillas and posterior mandibles, using Brånemark System Tiunite implants: an 18-month prospective clinical multicenter study.

BACKGROUND: Immediate or early loading of implants placed in maxillas and posterior mandibles has been a concern as bone density is often low in these areas, making it difficult to establish good initial implant stability. By adapting implant design and insertion protocols, however, high initial implant stability may be achieved in these regions. Further, a modified implant surface texture has been proved to help in maintaining stability during the initial healing period. PURPOSE: The aim of the present study was to investigate the clinical performance of oxidized titanium implants (TiUnite, Nobel Biocare AB, Gothenburg, Sweden) when used for early function in the maxilla and in the posterior mandible, locations where the bone density often is low. A further aim was to evaluate the marginal bone level at oxidized implants and compare it with that of machined-surface implants used in a previous study. MATERIALS AND METHODS: Thirty-one patients were consecutively included in the study, and 37 edentulous areas in maxillas and posterior mandibles were treated. Bruxism and uncontrolled periodontal disease were exclusion criteria. Temporary prostheses were generally placed within 9 days but not after 16 days from implant placement. A previous study applying the same study design and clinical protocol but using machined-surface implants was used for comparisons. RESULTS: Of the 111 implants installed, 1 failed, giving an overall survival rate of 99.1% after 18 months. The prosthesis survival was 100%. The marginal bone resorption was 0.8 mm (standard deviation [SD], 1.0), as opposed to 1.6 mm (SD, 1.3) in the previous study with machined-surface implants, but was not statistically significantly different (p = .10). CONCLUSION: The present clinical protocol (aiming at high primary stability) and the use of oxidized titanium implants for early functional loading in the maxilla and the posterior mandible resulted in a high implant survival rate and a favorable marginal bone level during a follow-up of 18 months. The difference in marginal bone resorption between the oxidized implants in the present study and the machined implants from a previous investigation with the same study design was not statistically significant.

Adult↗
PubMed2004

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 Brånemark 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 fixed 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.

Adult↗
PubMed2004

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.

Adolescent↗
PubMed2005

Screw preloads and measurements of surface roughness in screw joints: an in vitro study on implant frameworks.

BACKGROUND: With the development of milled titanium implant frameworks, new surfaces that have not previously been studied are now being used in screw joints. PURPOSE: The aims of the present study were to compare the preload produced in screw-retained titanium and gold alloy frameworks and the preload for titanium frameworks before and after the application of veneers. Another aim was to try to relate the surface roughness of the screw joints to variations in preload. MATERIALS AND METHODS: Ten identical titanium and five gold alloy frameworks were fabricated. The gold screws were tightened to 10 Ncm. Preload measurements were made for the gold alloy frameworks and before and after the porcelain or acrylic resin veneers had been applied to the titanium frameworks. Surface roughness measurements were made after preload measurements on the screw joint surfaces of the titanium frameworks and corresponding gold screws. RESULTS: The preloads for the titanium and gold alloy frameworks were similar. Preload in both types of frameworks decreased after repeated torques (p<.05-.01) but was unaffected by the application of veneering materials to the titanium frameworks (p>.05). No relationship (p>.05) between preload and surface roughness characteristics was observed. Loaded titanium framework screw sites, however, had lower mean S(a) values than unloaded sites (p<.001), whereas the surfaces of loaded gold screws had higher mean S(a) values compared with the surfaces of control gold screws (p<.05-.001). CONCLUSION: When using gold screws, milled titanium frameworks have preloads similar to those of gold alloy frameworks and preloads for both decrease after repeated tightening. The preload was similar before and after the veneering of the titanium frameworks. Unloaded milled titanium screw sites had rougher surfaces than loaded, and loaded gold screws had rougher surfaces than unloaded. However, no correlation between screw joint surface and preload was observed for veneered titanium frameworks.

Computer-Aided Design↗
PubMed2005

Biologic response of immediately versus delayed loaded implants supporting ill-fitting prostheses: an animal study.

BACKGROUND: Computer-assisted preoperative implant planning and transfer toward the patient allow the production of a prosthesis prior to surgery. This implies that the prosthesis can be installed immediately following implant insertion. An inherent disadvantage of this is a cumulated error, which can lead to prosthesis misfit owing to topographic deviations of the planned versus the installed implants. PURPOSE: The aim of this study was to determine whether prosthesis misfit is compromising the osseointegration of immediately versus delayed loaded implants and whether freshly installed implants adapt to the prosthesis. MATERIALS AND METHODS: In each of five New Zealand White rabbits, two experimental conditions were compared. One tibia harbored the so-called test implant, which originally showed a vertical misfit of about 500 microm with the prosthesis to which it was tightened immediately after implant installation. The control implant was installed in the other tibia and was allowed to heal during 9 weeks before the prosthesis with the vertical misfit of about 500 microm was connected to it. The prostheses were left in place for 12 weeks, after which the animals were sacrificed. RESULTS: All implants healed uneventfully. There were no statistically significant differences between the biologic responses of test and control implants. With a three-dimensional laser scanner, significantly more displacement of the test implants toward the prostheses was observed compared with the control implants. This led to a significant decrease in prosthesis misfit for the test implants compared with the control implants. CONCLUSIONS: This study indicates that prosthesis misfit does not per se lead to biologic failure of immediately loaded or of already osseointegrated implants. In addition, immediately loaded implants seem to topographically adapt to the prosthesis, thereby minimizing the existing misfit.

Alveolar Bone Loss↗
PubMed2005

Evaluation of 31 zygomatic implants and 74 regular dental implants used in 16 patients for prosthetic reconstruction of the atrophic maxilla with cross-arch fixed bridges.

BACKGROUND: The use of a specially designed implant to be anchored in the zygomatic body has been proposed as an alternative to bone grafting in the prosthetic rehabilitation of the severely resorbed maxilla. However, few studies have evaluated the long-term stability and soft tissue conditions of zygomatic implants. PURPOSE: The aim of this retrospective study was to evaluate the clinical performance of zygomatic implants when used for prosthetic reconstruction of atrophic maxillae. MATERIALS AND METHODS: Sixteen patients consecutively treated with 31 zygomatic implants and 74 additional dental implants from 1998 to 2002 were retrospectively evaluated and prospectively followed using a standardized clinical and radiographic study design. Data were collected from the time of implant treatment until the last follow-up RESULTS: The follow-up period ranged from 9 to 69 months from the day of implant treatment, with a mean of 46.4 months (3 years, 10 months). Three (9.7%) of the 31 zygomatic implants were surgically removed because of recurrent sinusitis. Three (4.1%) of the 71 additional dental implants failed to integrate. Poor oral hygiene and gingivitis were seen at most zygomatic implant sites (10/16). Local infections were observed in 9 of 16 patients. Sinusitis occurred in 6 patients. All patients (16/16) eventually received fixed bridges, which were stable throughout the observation period. CONCLUSIONS: The results showed an acceptable outcome with regard to implant and prosthetic survival rates. However, postoperative complications not related to implant and prosthesis stability were frequent. Further investigations of the long-term performance of zygomatic implants and with a focus on soft tissue and maxillary sinus health are needed.

Adult↗
PubMed2005

Stability of implant-abutment interface with a hexagon-mediated butt joint: failure mode and bending resistance.

BACKGROUND: Clinical data showed that the external hexagon implant system with a gold abutment screw has reduced the problem of screw loosening or fracture. However, the behavior of the implant-abutment joint components with respect to unfavorable bending force is still unclear. PURPOSE: This study investigated the joint instability and bending resistance of a single-tooth external hexagon implant system after lateral cyclic loading. MATERIALS AND METHODS: Fifteen implant assemblies (Nobel Biocare, Göteborg, Sweden) were divided equally into three groups: A, B, and C. Each assembly consisted of a Brånemark System Mk IV implant (4 x 10 mm) mounted in a brass block, a CeraOne abutment (3 mm), and an experimental cement-retained superstructure. For group A, a centric lateral cyclic load of 50 N was applied for 1.0 x 10(6), whereas for group B, the same load was eccentrically applied for 1.0 x 10(6) cycles. Group C, the control, was not loaded. After cyclic loading, specimens were mounted in a universal testing machine, and the yield and bending strengths were measured (kg). The external hexagon surface texture was examined using a secondary electron microscope. The data were analyzed with one-way analysis of variance and compared by the Tukey test (alpha = .05). RESULTS: For all test specimens, the abutment screw was plastically bent in the unthreaded portion. Group B had a significantly lower mean yield and bending strengths than group C (p = .005 and .010, respectively). Post-cyclic loading photographs showed that group B implants had marked burnishing around the hexagon corners. The bending force abraded both corner areas of the hexagon surface but left the middle area nearly intact for all tested groups. However, group B had the significantly lowest mean abraded area. CONCLUSION: Within the limits of this study, eccentric rather than centric lateral cyclic loading negatively affected the resistance of the implant-abutment joint to static bending.

Dental Abutments↗
PubMed2005

Direct implant loading in the edentulous maxilla using a bone density-adapted surgical protocol and primary implant stability criteria for inclusion.

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

Aged↗
PubMed2005

Immediate/early function of Brånemark System TiUnite implants in fresh extraction sockets in maxillae and posterior mandibles: an 18-month prospective clinical study.

BACKGROUND: 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. PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Adult↗
PubMed2006

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- 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.

Aged↗
PubMed1998

A prospective multicenter study evaluating loading of osseotite implants two months after placement: one-year results.

Historically, the recommended time between placement and functional loading of machined-surface dental implants has been 3 months for the mandible and 6 months for the maxilla. However, such recommendations are a result of evaluating randomly chosen healing times during the initial phase of implant development and are based on the subsequent clinical outcome of either implant integration or mobility. In recent years, histologic and experimental studies have shown that specifically designed micro-topographic implant surfaces can result in increased bone-to-implant contact at earlier healing times than obtained with machined-surface implants. Histologic and clinical studies investigating early and immediate implant loading support the premise that implants can be placed into function earlier than previously recommended. With the development of specifically designed implant surfaces and the utilization of time-saving surgical (one-stage surgical protocol) and prosthetic (implant position indexing) techniques, patients are now being restored and returning to function sooner than previously thought possible. The purpose of this multicenter clinical investigation is to evaluate the efficacy of loading Osseotite dental implants (3i-Implant Innovations Inc., Palm Beach Gardens, Florida) at 2 months and to determine the effect of early loading on implant performance and survival. A total of 429 Osseotite implants were placed in 155 patients (87 females and 68 males; mean age 54.0 +/- 13.7 yr), at 10 study centers, and subsequently loaded 2.1 +/- 0.7 months following placement. A single-stage surgical protocol was followed, with implants indexed immediately or impressed 4 to 6 weeks following placement. Patient restorative treatments included placement of 83 single-implant provisional restorations and 129 splinted, two-, three-, and four-implant supported maxillary and mandibular provisional restorations. The mean time from prosthetic loading to the most recent follow-up evaluation was 10 +/- 1.3 months. Seven of the 429 implants did not integrate; of these, six were identified prior to loading and one was identified 1 month after loading. The cumulative implant survival rate was 98.5% at 12.6 months. The cumulative post-loading implant survival rate was 99.8% at 10.5 months. The preliminary results of this clinical investigation suggest that successful functional loading of the Osseotite dental implant is possible at 2 months following noncomplicated implant placement.

Adult↗
PubMed2002

Spline implant prospective multicenter study: interim report on prosthetic screw stability in partially edentulous patients.

Loosening of implant abutment and prosthesis screws during functional loading is an industry-wide phenomenon that is especially well documented with the external hexagon implant connection. Although numerous efforts to reduce or eliminate screw loosening have been attempted, the problem still persists, especially with implant restorations in the partially edentulous patient. In 1992, the spline was developed as an alternative to the external hexagon implant-abutment connection. A prospective multicenter study was begun in 1996 to evaluate the abutment and prosthesis screw joint stability of Spline dental implants (Centerpulse Dental Division, Carlsbad, California) over 5 years of post-loading clinical follow-up. From October 1996 to December 2000, 73 partially edentulous patients were consecutively treated with 113 Spline implants placed in two private dental practices. Three patients with 1 implant each withdrew from the study for various reasons; of the remaining 110 implants in 70 patients who continued in the study, 82% (n = 90) were placed between 1997 and 1998. No cases of abutment or prosthesis screw loosening occurred with up to 54 months (mean = 38.95 mo; range, 3-54 mo; mode, 20 mo) of post-loading clinical follow-up. These interim findings of the ongoing study suggest that Spline dental implants may provide a stable prosthetic connection in partially edentulous cases during short-term clinical follow-up.

Dental Abutments↗
PubMed2001

Equivalence testing with dental clinical trials.

Clinical trials whose purpose are to show equivalence of two or more treatments have traditionally utilized methods for demonstrating superiority, and, if no statistical differences are found, the treatments are assumed to be equivalent. Methods for directly demonstrating equivalence have been developed by the pharmaceutical industry to establish the bioequivalence between drug formulations. This approach should have significant future implications for dental research. It is presently well-characterized in the statistical literature, but is virtually unknown within the dental literature and has had limited documented application with dental clinical trials. The purpose of this paper is to consider equivalence testing with dental clinical trials. Equivalence and superiority testing are contrasted, and comparisons between parallel and crossover designs with equivalence testing are discussed. To exemplify equivalency trial methodology for dental research application, several examples are proposed, including, in detail, an implant overdenture clinical trial to test the equivalence of treatment outcome between a two- and a four-implant overdenture treatment. Sample size calculations for otherwise-identical crossover and parallel equivalence studies are demonstrated. Results show that for a power of 0.90, a sample size of 24 is required for the crossover trial and over 150 subjects for the parallel design. For this dental research application, the equivalence/crossover design methodology is shown to be an efficient and appropriate approach.

Cross-Over Studies↗