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Primary Stability (primary + stability)

Distribution by Scientific Domains

Medical Sciences	95%

Selected Abstracts

Micromotion and Stress Distribution of Immediate Loaded Implants: A Finite Element Analysis

CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 4 2009
A. Fazel DDS
ABSTRACT Background: Primary stability and micromotion of the implant fixture is mostly influenced by its macrodesign. Purpose: To assess and compare the peri-implant stress distribution and micromotion of two types of immediate loading implants, immediate loaded screw (ILS) Nisastan and Xive (DENTSPLY/Friadent, Monnheim, Germany), and to determine the best macrodesign of these two implants by finite element analysis. Methods: In this experimental study, the accurate pictures of two fixtures (ILS: height = 13, diameter = 4 mm and Xive: height = 13, diameter = 3.8 mm) were taken by a new digital camera (Nikon Coolpix 5700 [Nikon, Japan], resolution = 5.24 megapixel, lens = 8× optical, 4× digital zoom). Following accurate measurements, the three-dimensional finite element computer model was simulated and inserted in simulated mandibular bone (D2) in SolidWorks 2003 (SolidWork Corp., MA, USA) and Ansys 7.1 (Ansys, Inc., Canonsburg, PA, USA). After loading (500 N, 75° above horizon), the displacement was displayed and von Mises stress was recorded. Results: It was found that the primary stability of ILS was greater (152 µm) than Xive (284 µm). ILS exhibited more favorable stress distribution. Maximum stress concentration found in periapical bone around Xive (,30 MPa) was lesser than Nisastan (,37 MPa). Conclusions: Macrodesign of ILS leads to better primary stability and stress distribution. Maximum stress around Xive was less. [source]

One-Stage Operative Procedure Using Two Different Implant Systems: A Prospective Study on Implant Overdentures in the Edentulous Mandible

CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 4 2001
Andrew Tawse-Smith DDS, Cert Perio (Göteborg)
ABSTRACT Background: Evidence-based reports are needed to support the application of a one-stage surgical protocol for unsplinted implants supporting mandibular overdentures. Purpose: To examine the feasibility and success of using two different dental implant systems (originally designed for two-stage operative technique) using a one-stage operative procedure in patients being rehabilitated with implant mandibular overdentures. Materials and Methods: The study sample involved 24 edentulous subjects (aged 55,80 yr) randomly allocated to two different implant systems, one with a machined titanium implant surface (Steri-Oss, Nobel Biocare, Göteborg, Sweden) and the other with a roughened titanium surface (Southern Implants, Ltd., Irene, South Africa). Two unsplinted implants to support implant overdentures were placed in the anterior mandible of all patients, using a standardized one-stage surgical and prosthodontic procedure. Primary stability and bicortical anchorage of the implants was mandatory before healing abutments were connected at the time of implant placement. Implant overdentures and their respective matrices were inserted following a standard 12-week healing period. Data relating to mobility tests, radiographs, and peri-implant parameters were documented at 12, 16, and 52 weeks after surgery. Results: A success rate of 95.8% for the Steri-Oss and 100% for the Southern Implants was found, without any statistically significant differences in the marginal bone loss. Significant changes in Periotest values were observed for both types between 12 and 52 weeks (p <.001). Minor changes were observed in the peri-implant parameters evaluated. Conclusions: These preliminary findings show a successful application of this one-stage approach for unsplinted implants supporting mandibular overdentures with Steri-Oss and Southern Implant Systems. [source]

Enhancing the mechanical integrity of the implant,bone interface with BoneWelding® technology: Determination of quasi-static interfacial strength and fatigue resistance

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2006
Stephen J. Ferguson
Abstract The BoneWelding® technology is an innovative bonding method, which offers new alternatives in the treatment of fractures and other degenerative disorders of the musculoskeletal system. The BoneWelding process employs ultrasonic energy to liquefy a polymeric interface between orthopaedic implants and the host bone. Polymer penetrates the pores of the surrounding bone and, following a rapid solidification, forms a strong and uniform bond between implant and bone. Biomechanical testing was performed to determine the quasi-static push-out strength and fatigue performance of 3.5-mm-diameter polymeric dowels bonded to a bone surrogate material (Sawbones solid and cellular polyurethane foam) using the BoneWelding process. Fatigue tests were conducted over 100,000 cycles of 20,100 N loading. Mechanical test results were compared with those obtained with a comparably-sized, commercial metallic fracture fixation screw. Tests in surrogate bone material of varying density demonstrated significantly superior mechanical performance of the bonded dowels in comparison to conventional bone screws (p < 0.01), with holding strengths approaching 700 N. Even in extremely porous host material, the performance of the bonded dowels was equivalent to that of the bone screws. For both cellular and solid bone analog materials, failure always occurred within the bone analog material surrounding and distant to the implant; the infiltrated interface was stronger than the surrounding bone analog material. No significant decrease in interfacial strength was observed following conditioning in a physiological saline solution for a period of 1 month prior to testing. Ultrasonically inserted implants migrated, on average, less than 20 ,m over, and interfacial stiffness remained constant the full duration of fatigue testing. With further refinement, the BoneWelding technology may offer a quicker, simpler, and more effective method for achieving strong fixation and primary stability for fracture fixation or other orthopaedic and dental implant applications. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source]

Micromotion and Stress Distribution of Immediate Loaded Implants: A Finite Element Analysis

Early Functional Loading of Unsplinted Roughened Surface Implants with Mandibular Overdentures 2 Weeks after Surgery

CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 3 2003
Alan G.T. Payne BDS, FCD (SA), MDent
ABSTRACT Background: Before early functional loading of unsplinted implants with mandibular overdentures can become widespread, more clinical studies are needed to investigate the success of the approach. Purpose: To evaluate the success rates of two types of roughened titanium surface implants with early 2-week functional loading of paired mandibular interforaminal implants with overdentures. Materials and Methods: Random allocation divided 24 strictly selected edentulous participants into two groups, with each group to receive a different implant system (ITI Dental Implant System, Straumann AG, Waldenburg, Switzerland; or Southern Implant System, Southern Implants, Irene, South Africa). Two implants were placed in the anterior mandible of all participants using one-stage standardized surgical procedures. Previously constructed conventional mandibular dentures (opposing maxillary complete dentures) were temporarily relined and worn by the participants for the first 2 weeks; participants used a soft diet. Two weeks after implant surgery and following some mucosal healing, the mandibular dentures had the tissue conditioner removed and the appropriate matrices included for an unsplinted prosthodontic design. Results: No implant from either group was lost. Resonance frequency analysis (RFA) indicated higher primary stability at surgery for the Southern group than for the ITI group, with a statistically significant difference between the groups throughout the study period. The drop in RF values between surgery and 6 weeks was significant and was greater for the Southern group. RFA also indicated stabilized osseointegration between 6 to 12 and 12 to 52 weeks, with no participant showing any decrease in those values over time. Participants with type 3 bone showed a significant improvement in RF values between 12 and 52 weeks, eventually matching those of participants with type 2 bone. There were no significant differences in marginal bone loss, periimplant parameters, or prosthodontic maintenance between the groups over the study period. Conclusions: Using only strict patient selection criteria, 1-year follow-up data indicate that early functional loading of ITI and Southern implants with mandibular two-implant overdentures is possible as early as 2 weeks after implant surgery. [source]

One-Year Prospective Three-Center Study Comparing the Outcome of a "Soft Bone Implant" (Prototype Mk IV) and the Standard Brånemark Implant

CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2 2003
Bertil Friberg DDS
ABSTRACT Background: Oral implant treatment ad modum Brånemark has been used for decades in the rehabilitation of edentate and partially dentate patients. Posterior jaw regions frequently exhibit bone of poor texture, and it is often difficult to obtain primary stability. Thus, it may prove beneficial to deviate from the original protocol and to use implants with a modified design, for example, with a slightly tapered geometry. Purpose: The purpose of the investigation was to compare the early behavior of a modified (prototype Mk IV, Branemark System, Nobel Biocare AB, Gothenburg, Sweden; test) implant with that of the standard Brånemark implant (control) in regions of mainly type 4 bone. Materials and Methods: Three Swedish centers participated, and a total of 44 patients were treated with oral implants for 39 maxillas and 5 mandibles. The study focused on the most distal right and left implant sites (88 implants), which were randomized to receive either a test or a control implant. Various parameters were recorded, such as registered insertion torque (OsseoCare, Nobel Biocare AB), wobbling during insertion, primary and secondary stability (as measured with resonance frequency), and marginal bone loss. The implants were followed up for 1 year. Results.: The test implant more frequently required a higher insertion torque and showed a significantly higher primary stability than the control implant. This difference in stability leveled out over time, and test and control implants exhibited similar secondary stability at abutment operation and at the 1-year visit. Wobbling during insertion was rarely recorded for either of the implant designs. The 1-year cumulative success rate was 93.1% for test implants and 88.4% for control implants. Conclusions: The modified implant design resulted in an increased primary stability, which may be important when placing implants in jaw regions of type 4 bone. However, independent of the achieved primary stability, successful implants tended to approach similar secondary stability in the two designs tested. [source]

Immediate Provisional for Single-Tooth Implant Replacement with Brånemark System: Preliminary Report

CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2 2001
Edward Hui MDS, FDSRCS, FRCDC
Abstract: Background: The success of osseointegrated implants ad modum Brånemark for single-tooth restorations is documented. Future developments should aim at improving the benefits to patients by decreasing treatment time, minimizing surgical stages, and maximizing esthetic outcomes. Using knowledge from studies of immediate implant placement, one-stage, immediate loading protocols, the authors developed the immediate provisional. Purpose: The purpose of this study was to develop a protocol to provide an immediate solution for restoring a single missing tooth in the esthetic zone. The protocol should be simple, predictable, cost effective, and allow the use of other techniques to improve esthetic outcome. Materials and Method: This prospective clinical study included 24 patients treated from August 1999 to October 2000. Single-tooth implant replacement was done according to immediate provisional protocol. Thirteen of the 24 patients had immediate implant placement after tooth extraction. All implants were placed in the esthetic zone. During surgery, emphasis was placed on obtaining primary stability by achieving bicortical anchorage and maximum insertion torque of at least 40 Ncm. CeraOne (Nobel Biocare) abutments were used, and provisional crowns were fabricated immediately before wound closure. The occlusion was protected by adjacent teeth. Results: Within the follow-up period of between 1 month and 15 months, all fixtures in the 24 patients were stable. Crestal bone loss greater than one thread-width was not detected. The esthetic result was considered satisfactory by all patients. Conclusions: The implant placement and restoration protocol used in this study showed promising initial results for both the immediate implant and healed extraction site groups. The desirable goals of patient satisfaction, excellent esthetic outcomes, and no increase in treatment cost were achieved in this protocol. Further studies to elucidate the potential of the immediate provisional protocol are justified. [source]

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

CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 1 2001
Alan G.T. Payne BDS, FCD(SA), MDent
ABSTRACT 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. [source]

Influence of surgical technique and surface roughness on the primary stability of an implant in artificial bone with different cortical thickness: a laboratory study

CLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2010
Afsheen Tabassum
Abstract Objective: The aim of this biomechanical study was to assess the interrelated effect of both surface roughness and surgical technique on the primary stability of dental implants. Material and methods: For the experiment, 160 screw-designed implants (Biocomp®), with either a machined or an etched surface topography, were inserted into polyurethane foam blocks (Sawbones®). As an equivalent of trabecular bone, a density of 0.48 g/cm3 was chosen. To mimic the cortical layer, on top of these blocks short-fibre-filled epoxy sheets were attached with a thickness varying from 0 to 2.5 mm. The implant sites were prepared using either a press-fit or an undersized technique. To measure the primary stability of the implant, both the insertion and the removal torques were scored. Results: Independent of the surgical technique used, both implant types showed an increased insertion and removal torque values with increasing cortical thickness, although >2 mm cortical layer no further increase in insertion torque was observed. In the models with only trabecular bone (without cortical layer) and with a 1 mm cortical layer, both implant types showed a statistically higher insertion and removal torque values for undersized compared with the press-fit technique. In addition, etched implants showed a statistically higher insertion and removal torque mean values compared with machined implants. In the models with 2 and 2.5 mm cortical layers, with respect to the insertion torque values, no effect of either implantation technique or implant surface topography could be observed. Conclusion: The placement of etched implants in synthetic bone models using an undersized preparation technique resulted in enhanced primary implant stability. A correlation was found between the primary stability and the cortical thickness. However, at or above a cortical thickness of 2 mm, the effect of both an undersized surgical approach, as also the presence of a roughened (etched) implant surface, had no extra effect. Besides the mechanical aspects, the biological effect of undersized drilling, i.e. the bone response on the extra insertion torque forces should also be elucidated. Therefore, additional in vivo studies are needed. To cite this article: Tabassum A, Meijer GJ, Wolke JGC, Jansen JA. Influence of surgical technique and surface roughness on the primary stability of an implant in artificial bone with different cortical thickness: a laboratory study. Clin. Oral Impl. Res. 21, 2010; 213,220. doi: 10.1111/j.1600-0501.2009.01823.x [source]

Immediate functional loading of implants in single tooth replacement: a prospective clinical multicenter study

CLINICAL ORAL IMPLANTS RESEARCH, Issue 8 2008
Mauro Donati
Abstract Objectives: The aim of the present study was to evaluate the outcome of immediate functional loading of implants in single-tooth replacement using two different installation procedures. Material and Methods: One hundred and fifty-one subjects, who required single-tooth rehabilitation in the area of 15,25 and 35,45, were enrolled in eight private clinics in Italy. The implant sites were randomly allocated to one of the following treatment groups. In the control group, in which a standard preparation procedure for implant placement and submerged healing of the implant was used, abutment connection and loading of the implants were performed 3 months after installation. In the test group 1, a standard preparation procedure for the implant placement and immediate functional loading of implant was carried out. In the test 2 group, however, a modified implant installation procedure (osteotome technique) was used followed by immediate functional loading of the implant. Clinical and radiographic examinations were performed at 3 and 12 months of follow-up at all sites. Results: Three implants (5.5%) from the test 2 group (osteotome preparation) and one (2%) from the test 1 group (conventional drill preparation) failed to integrate and were removed one and three months after implant installation. The mean marginal bone loss assessed at 12 months was 0.31 mm (test 1), 0.25 mm (test 2) and 0.38 mm (control) (no statistically significant differences were found between the three treatment groups.) Conclusion: It is suggested that immediate functional loading of implants that are placed with a conventional installation technique and with sufficient primary stability may be considered as a valid treatment alternative in a single-tooth replacement. [source]

Anatomic site evaluation of the palatal bone for temporary orthodontic anchorage devices

CLINICAL ORAL IMPLANTS RESEARCH, Issue 7 2008
Heinrich Wehrbein
Abstract: Objectives: The aim of the present study was to assess the micromorphologic characteristics of the palatal bone from an implantologic standpoint. Materials and Methods: The material consisted of tissue blocks of autopsy material from 22 subjects (18 males, three females) between 18 and 63 years of age. The specimens comprised the anterior median palatal region from 5 to 10 mm behind the incisive foramen. They were prepared in the transversal plane according to ground thin-section technology. The midpalatal area as well as an area of 3 mm bilateral to the midline were assessed, and a classification of quantitative palatal bone availability was developed. Results: The findings could be divided into three classes: (1) class I palatal bone consists almost of compact bone; (2) class II cortical bone layer on oral and nasal sides of palate, broad compact bone in the suture area (,3 mm), loose trabecular bone lateral to the suture area; and (3) class III cortical bone on oral and nasal side, thin compact bone in the suture area (<3 mm) and loose-structured trabecular bone lateral to the suture area. In most sections (72.7%), class I characteristics were found (16 subjects). 18.2% of sections were assigned to class II (four subjects) and only 9.1% of sections were assigned to class III (two subjects). Conclusion: These results document that in most cases a good primary stability of temporary orthodontic anchorage devices should be achieved in the midpalatal and paramedian area of the anterior palate, as the bone quantity available is high. [source]

Injectable calcium phosphate cement as a graft material for maxillary sinus augmentation: an experimental pilot study

CLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2008
Ali Aral
Abstract Objectives: The aim of the present study was to evaluate the efficiency of injectable CaP cement as a graft material around dental implants in the maxillary sinus augmentation procedure. Material and methods: Bilateral sinus augmentation process was carried out in three sheep and two implants were inserted during the same session. Out of a total of 12 installed implants, eight belonged to the so-called experimental group. In the experimental group, injectable CaP cement was used as augmentation material while autologous bone served as control. Results: Histological examination revealed that newly formed bone surrounded the cement completely without an intervening fibrous tissue layer. Following a healing period of 12 weeks, mean bone-to-implant contact (BIC) values in the experimental and control groups were 36±5 and 37±3, respectively. The percentage of BIC was comparable with other experimental sinus augmentation studies. Further, it appeared that the thickness of the cortical bone that covered the outer surface of the maxillary sinus was <2,3 mm, which affected the primary stability of the implants negatively. Conclusion: CaP cement is indeed effective to stimulate bone formation in the sinus elevation procedure. Nevertheless, additional improvements in the cement composition are required to allow final clinical utilization of the material. [source]

Bone density and primary stability in implant therapy

CLINICAL ORAL IMPLANTS RESEARCH, Issue S2 2006
Liene Molly
Abstract Introduction: To improve patient comfort, deviations from the very successful standard osseointegration protocol are being developed. To keep implant failure rates as low as possible, the most perfect treatment planning and a good patient selection are extremely important. Because bone density plays an important role in implant outcome, known relations of bone density could improve treatment planning. Material and methods: A Pubmed search revealed 66 manuscripts investigating and discussing bone density of human jawbone whether or not related to implant stability or outcome. Forty-five of these will be discussed in this review. Results and discussion: Many pre-operative methods of jawbone density assessment are available. Most of those techniques correlate well with one another. Some are more elaborate to use in clinical practice. Primary stability measurements show significant correlations with different bone densities and also with implant outcome; however, not many studies investigate both at the same time. Conclusion: To investigate the outcome of adaptation methods of the surgical protocol with regard to the jawbone density, an objective pre-surgical determination of bone density is necessary. [source]

Significance of primary stability for osseointegration of dental implants

CLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2006
Natalia Lioubavina-Hack
Abstract Aim: To investigate the significance of the initial stability of dental implants for the establishment of osseointegration in an experimental capsule model for bone augmentation. Material and methods: Sixteen male rats were used in the study. In each rat, muscle-periosteal flaps were elevated on the lateral aspect of the mandibular ramus on both sides, resulting in exposure of the bone surface. Small perforations were then produced in the ramus. A rigid, hemispherical Teflon® capsule with a diameter of 6 mm and a height of 4 mm and with a hole in its middle portion, prepared to fit the circumference of an ITI® HC titanium implant of 2.8 mm in diameter, was fixed to the ramus using 4 mini-screws. On one side of the jaw, the implant was placed through the hole in such a way that its apex did not make contact with the mandibular ramus (test). This placement of the implant did not ensure primary stability. On the other side of the jaw, a similar implant was placed through the hole of the capsule in such a way that contact was made between the implant and the surface of the ramus (control). This provided primary stability of the implant. After placement of the implants, the soft tissues were repositioned over the capsules and sutured. After 1, 3, 6 and 9 months, four animals were sacrificed and subjected to histometric analysis. Results: The mean height of direct bone-to-implant contact of implants with primary stability was 38.8%, 52.9%, 64.6% and 81.3% of the implant length at 1, 3, 6 and 9 months, respectively. Of the bone adjacent to the implant surface, 28.1%, 28.9%, 52.6% and 69.6%, respectively, consisted of mineralized bone. At the test implants, no bone-to-implant contact was observed at any observation time or in any of these non-stabilized specimens. Conclusion: The findings of the present study indicate that primary implant stability is a prerequisite for successful osseointegration, and that implant instability results in fibrous encapsulation, thus confirming previously made clinical observations. [source]

Predicting osseointegration by means of implant primary stability

CLINICAL ORAL IMPLANTS RESEARCH, Issue 5 2004
A resonance-frequency analysis study with delayed, immediately loaded ITI SLA implants
Abstract: The purpose of the present clinical study was (1) to evaluate the Osstell as a diagnostic tool capable of differentiating between stable and mobile ITI implants, (2) to evaluate a cut-off threshold implant stability quotient (ISQ) value obtained at implant placement (ISQitv) that might be predictive of osseointegration, (3) to compare the predictive ISQitv of immediately loaded (IL) implants and implants loaded after 3 months (DL). Two patient groups were enrolled, 18 patients received 63 IL implants and 18 patients were treated with 43 DL implants. The ISQ was recorded at implant placement, after 1, 2, 4, 6, 8, 10 and 12 weeks. All implants passed the 1-year loading control. Two implants failed, one DL implant with ISQ at placement (ISQi) of 48 and one IL implant with ISQi of 53. The resonance-frequency analysis (RFA) method was not a reliable diagnostic tool to identify mobile implants. However, implant stability could be reliably determined for implants displaying an ISQ,47. After 1 year of loading, all DL implants with an ISQi,49 and all IL implants with an ISQi,54 achieved and maintained osseointegration. By the end of 3 months, implants with ISQi<60 had an increase of stability. Implants with ISQi 60,69 had their stability decrease during 8 weeks before returning to their initial values. Implants with ISQ>69 had their stability decrease during the first 4 weeks before remaining stable. Although preliminary, these data might orient the practitioner to choose among various loading protocols and to selectively monitor implants during the healing phase. Résumé Le but de l'étude clinique présente a été 1) d'évaluer l'Osstell comme machine de diagnostic capable de différencier l'implant ITI stable et du mobile, 2) d'évaluer un niveau seuil de la valeur du quotient de stabilité implantaire obtenue lors du placement de l'implant (ISQitv) qui pourrait être prophétique pour l'ostéoïntégration, 3) de comparer le jugement ISQitv d'implants immédiatement mis en charge (IL) et d'implants chargés trois mois après leur placement(DL). Deux groupes de patients ont participéà cette étude : 18 patients ont reçu 63 implants IL et 18 autres ont été traités avec 43 implants DL. Le ISQ a été enregistré lors du placement de l'implant et après 1, 2, 4, 6, 8, 10 et 12 semaines. Tous les implants ont passé le contrôle de mise en charge d'une année. Deux implants ont échoué, un DL avec un ISQ lors de son placement de 48 et un implant IL avec un ISQi de 53 lors de son placement. La méthode RFA n'était pas un outil de diagnostic fiable pour identifier les implants mobiles. Cependant la stabilité implantaire pouvait être déterminée de manière sûre pour les implants qui avaient un ISQi 47. Après une année de mise en charge, tous les implants DL avec un ISQi 49 et tous les implants IL avec un ISQi 54 atteignaient et maintenaient l'ostéoïntégration. Après trois mois, les implants avec ISQi 60 montraient une augmentation de stabilité. Les implants avec ISQi de 60 à 69 avaient une diminution de la stabilité durant huit semaines avant de revenir à leur valeur initiale. Les implants avec ISQ>69 voyaient leur stabilité diminuée durant les premières quatre semaines avant de rester stables. Bien que préliminaires, ces données peuvent orienter le praticien pour choisir parmi différents protocoles de mise en charge et de suivre de manière sélective les implants durant la phase de guérison. Zusammenfassung Das Ziel dieser klinischen Studie war, 1) das Osstell als diagnostisches Werkzeug zur Unterscheidung von stabilen und beweglichen ITI-Implantaten zu untersuchen, 2) einen verbindlichen Grenzwert zu bestimmen, der in Form eines Implantatstabilitätsquotienten zum Zeitpunkt der Implantation (ISQitv) erhoben wird, und der als Voraussagewert für die Osseointegration dienen könnte, 3) den ISQitv von sofortbelasteten Implantaten (IL) und von erst nach 3 Monaten belasteten Implantaten (DL) zu vergleichen. Es waren zwei Patientengruppen beteiligt, 18 Patienten erhielten 63 IL-Implantate und 18 Patienten wurden mit 43 DL-Implantaten behandelt. Den ISQ-Wert bestimmte man sofort nach der Implantation, sowie nach 1, 2, 4, 6, 8, 10 und 12 Wochen. Alle Implantate konnten nach einem Jahr überprüft und kontrolliert werden. 2 Implantate gingen verloren, ein DL-Implantat mit einem ISQ bei der Implantation (ISQi) von 48 und ein IL-Implantat mit einem ISQi von 53. Die RFA-Methode war kein verlässliches diagnostisches Werkzeug, um bewegliche Implantate zu erkennen. Man konnte aber für Implantate mit einem ISQ von>47 die Implantatstabilität verlässlich bestimmen. Nach einer Belastung über ein Jahr erreichten alle DL-Implantate mit einem ISQi von>49 und alle IL-Implantate mit einem ISQi von>54 eine stabile Osseointegration. Nach 3 Monaten, erreichten Implantate mit einem ISQi von<60 eine zunehmende Stabilität. Implantate mit einem ISQi von 60-69 verloren in den ersten 8 Wochen einen Teil ihrer Stabilität, bevor sie wieder zu den Anfangswerten zurückkehrten. Implantate mit einem ISQ>69 hatten ihre Stabilitätsabnahme in den ersten 4 Wochen, bevor sie wiederum dauerhaft stabil wurden. Obwohl es erste Daten sind, können sie dem Praktiker helfen, um zwischen den verschiedenen Belastungsprotokollen zu wählen, und um die Implantate ganz individuell durch die Heilungsphase hindurch zu betreuen. Resumen El propósito del presente estudio fue, 1) evaluar el Osstell como herramienta diagnóstica capaz de de diferenciar entre implantes ITI estables y móviles, 2) evaluar un valor de cociente de umbral de corte de estabilidad de implante obtenido al colocar el implante (ISQitv) que pueda ser predictivo de osteointegración, 3) comparar la predictibilidad del ISQitv de los implantes de carga inmediata (IL) e implantes cargados tras 3 meses (DL). Se enroló a dos grupos de pacientes, 18 pacientes recibieron 63 implantes IL y 18 pacientes se trataron con 43 implantes DL. Se recogieron los ISQ al colocar los implantes, tras 1, 2, 4, 6, 8, 10 y 12 semanas. Todos los implantes superaron el control del año. 2 implantes fracasaron, un implante DL con un ISQ al colocarlo (ISQi) de 48 y un implante IL con un ISQi de 53. El método RFA no fue una herramienta fiable para identificar implantes móviles. De todos modos, la estabilidad de los implantes pudo ser determinada con fiabilidad para los implantes que mostraron un ISQ,47. Tras 1 año de carga, todos los implantes DL con un ISQi,49 y todos los IL con ISQi,54 lograron y mantuvieron la osteointegración. Al final de los 3 meses, los implantes con ISQ<60 tuvieron un incremento en la estabilidad. Los implantes con un ISQi de 60-69 tuvieron un descenso de la estabilidad durante 8 semanas antes de volver a sus valores iniciales. Los implantes con ISQ>69 tuvieron un descenso de la estabilidad durante la primeras 4 semanas antes de estabilizarse. Aunque preliminares, estos datos pueden orientar al clínico a escoger entre varios protocolos de carga y monitorizar selectivamente los implantes durante la fase de cicatrización. [source]

Influence of implant taper on the primary and secondary stability of osseointegrated titanium implants

CLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2004
Dominic O'Sullivan
Abstract Objectives: The study presented was designed to analyse the mechanical performance and the primary and secondary stability characteristics of endosseous titanium implants with 1° (EXP1) and 2° (EXP2) of taper when compared with the standard Brånemark design (Nobel Biocare AB, Gothenburg, Sweden). Materials and methods: One pair of 10 mm EXP1 and control implants were placed in the femoral condyles of six rabbits. Paired 6 mm EXP1 and control implants and 6 mm EXP2 and control implants were placed in the tibial metaphysis. The control implants used were 4 mm diameter standard Brånemark implants, the same length as the test implants. At placement, insertion torque (IT) and resonance frequency analysis (RFA) measurements were performed. Six weeks postoperatively when the animals were killed, RFA and removal torque (RT) measurements were made. Results: At placement, significantly higher IT was needed to insert the EXP implants compared with the controls. RFA values were significantly higher for EXP1 implants placed in the tibia but not in the femur. In pooling data from the femur and tibia there was a significant difference. The EXP2 implants failed to insert fully and demonstrated a lower RFA value than may have been expected due to the exposed threads, although this difference was not statistically significant. Conclusions: The results from the present study showed that 1° of taper results in a better primary stability compared with the standard Brånemark design. There was no evidence that the tapered design caused negative bone tissue reactions. All the implants gained in stability during the healing period. Résumé L'étude présente a été effectuée pour analyser la performance mécanique et les caractéristiques de stabilité primaire et secondaire d'implants endoosseux en titane avec un taper (fuselé) 1° (EXP1) et 2 (EXP 2) comparés au modèle ad modum Branemark® standard. Une paire d'implants contrôles et un EXP1 de 10 mm ont été placés dans les condyles fémoraux de six lapins. Des paires d'implants contrôles et EXP1 de 6 mm et des implants contrôles et EXP2 de 6 mm ont été placés dans les métaphyses tibiales. Les implants contrôles utilisés avaient un diamètre standard de 4 mm, la même longueur que les implants tests. Lors du placement, des mesures de force d'insertion (IT) et d'analyse de fréquence de résonnance (RFA) ont été effectuées. Six semaines après l'opération lorsque les animaux ont été euthanasiés, les mesures RFA et les forces d'enlèvement (RT) ont été relevées. Lors du placement un IT significativement plus important a été nécessaire pour insérer les implants EXP1 comparé au contrôle. Les valeurs RFA étaient significativement plus importantes pour les implants EXP1 placés dans le tibia mais pas dans le fémur. En rassemblant les données du fémur et du tibia il y avait une différence significative. Les implants EXP2 ne parvenaient pas àêtre insérés à fond et ont montré une valeur RFA inférieure qui n'était pas inattendue vu les filetages exposés bien que ces différences n'étaient pas statistiquement significatives. Les résultats de l'étude présente ont montré que le taper 1 résultait en une stabilité primaire supérieure comparé au modèle ad modum Branemark® standard. Il n'y avait aucun signe que ce nouveau modèle causait des réactions tissulaires osseuses négatives. Tous les implants ont gagné en stabilité durant leur période de guérison. Zusammenfassung Ziele: Die hier vorgestellte Studie hatte zum Ziel, das mechanische Verhalten und die Charakteristika von Primär- und Sekundärstabilität bei enossalen Implantaten mit einer Gewindeneigung von 1° (EXP1) und von 2° (EXP2) zu untersuchen. Man verglich die Daten mit dem Standarddesign von Brånemark (Nobel Biocare AB, Gothenburg, Schweden). Material und Methode: Man implantierte ein Päärchen von 10mm-Implantaten (EXP1 und Kontrollimplantat) in die Femurkondylen von 6 Kaninchen. Zwei weitere Päärchen von 6mm-Implantaten (EXP1 und Kontrollimplantat, sowie EXP2 und Kontrollimplantat) implantierte man in die Metaphyse der Tibia. Bei den Kontrollimplantaten handelte es sich um Standardtypen von Brånemark mit einem Durchmesser von 4 Millimetern und derselben Länge wie die Testimplantate. Bei der Implantation mass man die Kraft, die es zu Eindrehen der Implantate brauchte (IT) und führte Messungen mit der Resonanzfrequenzanalyse (RFA) durch. Sechs Wochen nach der Operation wurden die Tiere geopfert, die RFA erneut durchgeführt und anschliessend der Ausdrehwiderstand (RT) bestimmt. Resultate: Bei der Implantation brauchte es signifikant grössere IT um die EXP-Implantate einzusetzen, als bei den Kontrollimplantaten. Die RFA-Werte waren bei den EXP1-Implantaten, die in die Tibia geschraubt worden waren, signifikant höher. Dies gilt aber nicht für die in den Femur geschraubten Implantate. Wurden die Daten vom Femur mit denen der Tibia verglichen, so erkannte man signifikante Unterschiede. Die EXP2-Implantate konnten nicht vollständig inseriert werden und zeigten auch tiefere RFA-Werte, als man den freiliegenden Schraubenwindungen entsprechend erwarten könnte. Diese Unterschiede waren aber nicht statistisch signifikant. Zusammenfassung: Die Resultate dieser Studie zeigten, das Schraubenwindungen mit 1° Steigung verglichen mit dem Standarddesign von Brånemark eine bessere Primärstabilität erzielten. Man fand andererseits keine Beweise, dass sich dieses neue Design der Schraubenwindungen negativ auf die Reaktion des Knochengewebes auswirkt. Alle Implantate gewannen während in der Heilphase an Stabilität dazu. Resumen Objetivos: El estudio presentado se diseñó para analizar el rendimiento mecánico y las características de estabilidad primaria y secundaria de implantes endoóseos de titanio con 1o (EXP1) y 2o (EXP 2) de autoroscado al compararlos con el diseño estándar de Brånemark (Nobel Biocare AB, Gothenburg, Suecia). Material y Métodos: Se colocó una pareja de implantes de 10 mm EXP1 y de control en los cóndilos femorales de 6 conejos. Se colocaron pareja de implantes de 6 mm EXP1 y de control y de 6 mm EXP2 y de control en la metáfisis tibial. Los implantes de control utilizados fueron Brånemark estándar de 4 mm de diámetro. A la colocación, se llevaron a cabo mediciones del torque de inserción (IT) y del análisis de la frecuencia de resonancia (RFA). Los animales se sacrificaron a las seis semanas de la operación, y se tomaron medidas del torque de remoción (RT). Resultados: Al colocarse, se necesitó un IT significativamente mas alto para insertar los implantes EXP en comparación con los de control. Los valores RFA fueron significativamente mas altos para implantes EXP1 colocados en la tibia pero no en el fémur. Confrontando los datos del fémur y de la tibia apareció una diferencia significativa. Los implantes EXP2 fracasaron en insertarse completamente y demostraron un menor valor de RFA del que se podía esperar debido a la exposición de las roscas, aunque esta diferencia no fue estadísticamente significativa. Conclusiones: Los resultados del presente estudio mostraron que 1o de autoroscado resultan en una mejor estabilidad primaria comparada con el diseño estándar de Brånemark. No hubo evidencia de que el diseño de autoroscado causara reacciones negativas en el tejido óseo. Todos los implantes ganaron estabilidad durante el periodo de cicatrización. [source]