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ABSTRACT: BACKGROUND: Extensive alveolar bone resorption in the maxilla limits the possibility of successful placement and osseointegration of endosseous implants for future prosthetic rehabilitation. Autogenous bone from the iliac crest may be used as lateral onlays in the atrophic maxilla, both as block and particulate bone. To our knowledge, there is no three-dimensional 2-year follow-up study measuring the volumetric reduction of the augmented areas comparing particulate and block bone grafts. PURPOSE: The aim of this study was to conduct a radiographic 2-year follow-up study, using computed tomographic (CT) images in order to evaluate and compare the extent of bone graft resorption in the frontal maxillae augmented by particulate (test) and block bone (control). MATERIAL AND METHODS: Eleven patients treated with iliac bone grafts and oral implants in the maxilla were followed with CT examinations directly post grafting and after 2years. RESULT: The volumetric changes after 6months were extensive. Additionally, the changes in particulate bone tended to be larger after 2years compared to block bone, using this protocol. However, the difference was not statistically significant. CONCLUSION: The present follow-up study showed that there is radiographically complete integration and embedding of implants installed in grafted bone despite extensive initial graft resorption. There was no significant difference in the amount of volumetric reduction between particulate bone and block bone grafts.
Journal of cranio-maxillo-facial surgery: official publication of the European Association for Cranio-Maxillo-Facial Surgery 12/2011; · 1.25 Impact Factor
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ABSTRACT: Background: Extensive atrophy of the alveolar process may require a bone-grafting procedure prior to implant treatment. Autogenous bone grafts from the iliac crest, used as onlay block and particulate bone, have been used together with sinus-lift procedure in order to rehabilitate patients with extremely resorbed maxillae. However, there are to our knowledge no 5-year follow-up studies evaluating the extent of bone-level change in patients treated with respectively block and particulate autogenous bone grafts. Purpose: The purpose of this prospective clinical study was to conduct a 5-year follow-up analysis with focus on bone-level alteration in block versus particulate onlay bone grafts. Material and Methods: Fifteen out of originally 19 patients who were treated with iliac bone grafts and oral implants in the maxilla have been followed through the first 5 postoperative years. In a first study conducted on 19 patients, the role of platelet-rich plasma in conjunction with autogenous bone was evaluated. In this 5-year follow-up study, the marginal bone alterations have been documented at base line, 1 year and 5 years of loading to the nearest 0,1 mm at mesial and distal surfaces of the implants. Two implants were installed on each side of the midline in either block or particulate bone grafts giving test and control sides in each patient. Additionally, two implants on each side were installed in residual bone/grafted sinus floor. Result: Marginal bone alteration in the anterior maxilla appeared larger at the side augmented by block bone at baseline, and after 1 and 5 years of loading, but the change was not statistically significant. Moreover, there was a significantly higher degree of marginal alteration during the first year of loading, compared with the examinations after 5 years. Conclusion: The present follow-up study showed that there is no significant difference in the extension of resorption between block- and particulate autogenous bone grafts over a 5-year period. Most of the resorption occurred during the first year in function.
Clinical Implant Dentistry and Related Research 08/2011; · 3.53 Impact Factor
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ABSTRACT: The aims of this study were to evaluate the frequency of errors in panoramic radiographs in young orthodontic patients, to register pathologic and abnormal conditions, and to compare these findings with the patient's record. A total of 1287 panoramic radiographs of children and adolescents (530 boys and 757 girls; mean age 14.2 years) were analyzed. The radiographs were obtained of patients referred for orthodontic treatment during a 1 year period. Four observers evaluated the radiographs for 10 common errors, pathologies, and/or anomalies. Cohen's kappa was used for the calculations of inter- and intraobserver variability. Five of the errors were divided into clinically relevant or not clinically relevant errors, i.e. errors influencing diagnosis. Only those pathological findings with a possible influence on orthodontic treatment were compared with the patient's record. Of the 1287 radiographs, 96 per cent had errors. The number of errors in each image varied between 1 and 5, and in 24 per cent of these images, the errors could be of importance for clinical decision making. The most common error was that the tongue was not in contact with the hard palate. Pathologies or anomalies were found in 558 patients and a total of 1221 findings were recorded. Findings of possible relevance for orthodontic treatment were 63, and 12 of those were registered in the patient records. Pathological findings outside the dental arches were low and could be an argument for minimizing the radiation field.
The European Journal of Orthodontics 04/2011; 34(4):452-7. · 0.89 Impact Factor
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ABSTRACT: The aim of this case series was to analyse dimensional alterations of the alveolar ridge and tooth-supporting structures, as well as root resorption, following orthodontic tooth movement into edentulous areas with reduced ridge dimensions. The study involved six subjects (30-70 years) with 10 edentulous jaw areas in the premolar regions. Clinical and radiographic examinations and 3D measurements on scanned study casts were performed at baseline, at retention, and after 1 year of (i) the edentulous area into which the tooth was moved and (ii) the established edentulous area from which the tooth was moved. The orthodontic tooth movement into an edentulous area resulted in most individuals in only minor dimensional alterations of the periodontal tissues. With regard to the width of the alveolar process, the results indicated a decreased width in the newly established edentulous area, whereas in the area into which the tooth had been moved, the width increased. In all cases, the moved tooth showed lateral root resorption on its pressure side at the level of the bone crest at time of retention, but signs of repair were noticed at the 1-year follow-up. Within the limitations of the study, it can be concluded that orthodontic tooth movement results in dimensional alterations of the edentulous ridge and that lateral root resorption is an inevitable side-effect.
The European Journal of Orthodontics 03/2011; · 0.89 Impact Factor
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ABSTRACT: The technical development has given a new type of modality, cone-beam computed tomography (CBCT). This technique has a high potential to solve different diagnostic problems among which is preoperative planning for implants in the posterior mandible.
The aim of this retrospective study was to evaluate the visibility of the mandibular canal and the marginal bone crest and the agreement between observers in images from one CBCT technique.
Thirty consecutive patients were examined with 3D Accuitomo (J. Morita Mfg. Corp., Kyoto, Japan) in one side of the mandible, where the second premolar and molars were lost. The examined volume was 30 by 40 mm. Seven observers evaluated the visibility and the location of the mandibular canal and the marginal crest by visually deciding if the structures were clearly visible, probably visible, or invisible in one cross-sectional image, approximately 1 cm posterior to the mental foramen. In a later session, the observers also marked the two anatomic structures. If the decision was not "clearly visible" or if the anatomic structures were difficult to identify, the observers had to use other cross-sectional, axial, and/or sagittal images in the volume.
The confidence among the observers evaluating the marginal bone crest was high. Two observers never used any other images, and the rest took help in two to seven cases. When marking the mandibular canal, the observers, in general, used more images. In five cases (17%), all the observers only used the single cross-sectional image. The agreement on the position of the canal was also high.
With this CBCT modality (3D Accuitomo), the visibility of the mandibular canal and the marginal crest, as well as the observer agreement of the location of these structures, was high. Hence, the 3D Accuitomo can be recommended for implant planning in the posterior mandible.
Clinical Implant Dentistry and Related Research 10/2008; 11(3):246-55. · 3.53 Impact Factor
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ABSTRACT: Comparatively few studies are available reporting at least 5 years of follow-up data of implant-supported single-tooth replacements.
To evaluate prospectively the 5-year outcome of implant-supported single-tooth prosthetic restorations.
Forty subjects (mean age 41 years), 23 males and 17 females, who required single-tooth prosthetic replacement for a missing tooth were recruited. A total of 45 self-tapping implants (Astra Tech ST-implants)--40 in the maxilla and five in the mandible--were installed in a two-stage procedure. Abutment connection was performed 3-6 months after implant installation. Clinical and radiographic examinations were performed at the completion of the prosthetic treatment and once a year during a 5-year follow-up period. The analysis of peri-implant bone level alteration was performed on subject and implant levels and by the use of analysis of variance and binary logistic regression.
Three patients were lost during the 5 years of follow-up. One implant was lost after 2.5 years in function and another four implants could not be accounted for at the 5-year follow-up examination. The overall failure rate at 5 years was 2.6% (subject level) and 2.3% (implant level). The mean loss of marginal bone at the implants during the first year in function was 0.06 mm (SD 0.67) on the subject level and 0.02 mm (0.65) on the implant level. During the subsequent 4 years the annual change in peri-implant bone level amounted to -0.02 mm (0.22) on both subject and implant levels. Thus, the mean total bone level change over the 5-year interval was -0.14 mm (1.04) on subject level and -0.11 mm (1.00) on the implant level of analysis (p>0.05). The frequency of implants with a 5-year bone loss of > or =1 mm was 13%. Approximately 50% of the implants demonstrated no bone loss.
The present clinical trial on single-tooth replacements with the Astra Tech implant system demonstrated that the bone loss during the first year of function as well as annually thereafter was small.
Journal Of Clinical Periodontology 07/2005; 32(6):567-74. · 3.00 Impact Factor
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ABSTRACT: The aim of this study was to retrospectively analyze whether the inclusion of cantilever extensions increased the amount of marginal bone loss at free-standing, implant-supported, fixed partial dentures (FPDs) over a 5-year period of functional loading.
The patient material comprised 45 periodontally treated, partially dentate patients with a total of 50 free-standing FPDs supported by implants of the Astra Tech System. Following FPD placement (baseline) the patients were enrolled in an individually designed supportive care program. A set of criteria was collected at baseline to characterize the FPDs. The primary outcome variable was change in peri-implant bone level from the time of FPD placement to the 5-year follow-up examination. The comparison between FPDs with and without cantilevers was performed at three levels: FPD level, implant level, and surface level. Bivariate analysis was performed by the use of the Mann-Whitney U-test and stepwise regression analysis was utilized to evaluate the potential influence of confounding factors on the change in peri-implant bone level.
The overall mean marginal bone loss for the implant-supported FPDs after 5 years in function was 0.4 mm (SD, 0.76). The bone level change at FPDs placed in the maxilla was significantly greater than that for FPDs in the mandible (0.6 versus 0.2 mm; p<0.05). No statistically significant differences were found with regard to peri-implant bone level change over the 5 years between FPDs with and without cantilevers at any of the levels of comparisons. The multivariate analysis revealed that the variables jaw of treatment and smoking had a significant influence on peri-implant bone level change on the FPD level, but not on the implant or surface levels. The model explained only 10% of the observed variance in the bone level change.
The study failed to demonstrate that the presence of cantilever extensions in an FPD had an effect on peri-implant bone loss.
Journal Of Clinical Periodontology 12/2004; 31(12):1077-83. · 3.00 Impact Factor
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ABSTRACT: Comparatively few studies with at least 5 years of follow-up are available that describe the use of implants in prosthetic rehabilitation of partially edentulous patients. Randomized, controlled clinical studies that evaluated the effect of different surface designs of screw-shaped implants on the outcome of treatment are also sparse.
To determine, in a prospective randomized, controlled clinical trial, the outcome of restorative therapy in periodontitis-susceptible patients who, following basic periodontal therapy, had been restored with implants with either a machined- or a rough-surface topography.
Fifty-one subjects (mean age, 59.5 years), 20 males and 31 females who, following treatment of moderate-to-advanced chronic periodontitis, required implant therapy for prosthetic rehabilitation were recruited. Seventeen of the patients were current smokers. Following the active treatment, all subjects were included in an individually designed maintenance program. A total of 56 fixed partial dentures (FPDs) and a total of 149 screw-shaped, and self-tapping implants (Astra Tech implants) -- 83 in the maxilla and 66 in the mandible -- were installed in a two-stage procedure. Each patient received a minimum of two implants and by randomization every second implant that was installed had been designed with a machined surface and the remaining with a roughened Tioblast surface. Abutment connection was performed 3-6 months after implant installation. Clinical and radiographical examinations were performed following FPD connection and once a year during a 5-year follow-up period. The analysis of peri-implant bone-level alterations was performed on subject, FPD and implant levels.
Four patients and four FPDs were lost to the 5 years of monitoring. One implant (machined surface) did not properly integrate (early failure), and was removed at the time of abutment connection. Three implants were lost during function and a further eight implants could not be accounted for at the 5-year follow-up examination. The overall failure rate at 5 years was 5.9% (subject level), 5.3% (FPD level) and 2.7% (implant level). Radiographic signs of loss of osseointegration were not found at any of the implants during the 5-year observation period. During the first year in function there was on average 0.33 (SD, 0.61) mm loss of peri-implant marginal bone on the subject and FPD levels and 0.31 (0.81) mm on the implant level. During the subsequent 4 years, the peri-implant bone-level alterations were small. The calculated annual change in peri-implant bone level was -0.02 (0.15) on subject and FPD levels and -0.03 (0.20) on the implant level. Thus, the mean total bone-level change over the 5-year interval amounted to 0.41 mm on all three levels of analysis. In the interval between baseline and 5 years, the machined and the Tioblast implants lost on average 0.33 and 0.48 mm, respectively (p>0.05).
The present randomized, controlled clinical trial that included partially edentulous periodontitis-susceptible subjects demonstrated that bone loss (i) during the first year of function as well as annually thereafter was small and (ii) did not vary between implants with machined- or rough-surface designs.
Journal Of Clinical Periodontology 10/2004; 31(9):713-24. · 3.00 Impact Factor
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ABSTRACT: It was hypothesized that the bending stiffness of the mandible is an important biomechanical parameter in implant dentistry. It was shown how this bending stiffness can be estimated by means of the principal area moments of inertia of the cortical and cancellous cross-sections as obtained by computed tomography, some image processing and subsequent calculation. It was found that the contribution of the cancellous bone to the bending stiffness is normally insignificant and that the principal area moments of inertia of the cortical cross-section show large variations, depending on the degree of resorption. It was furthermore found that the variations in the principal area moments of inertia of the cortical cross-section in one and the same potential implant patient were minor. Finally, in a three-dimensional finite element study, it was found that the peak bone stresses adjacent to implants, resulting from a standardized load at the distal end of an implant-supported bridge, were inversely related to the magnitude of the principal area moment of inertia about the horizontal axis of the cortical cross-section. It was concluded that the principal area moments of inertia of the cortical cross-section and the angulation of the principal axes of inertia might be useful as a quantitative characterization of the mandible stiffness in clinical research and perhaps also in clinical practice.
Clinical Oral Implants Research 09/2004; 15(4):450-8. · 2.51 Impact Factor
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ABSTRACT: A prospective study of one-stage surgery with intrasinus bone transplant and implants has been performed in 26 patients (13 males and 13 females). The aim of the study was to evaluate the success rate with the one-stage sinus lifting procedure in patients with a need for bony augmentation of the alveolar process. Fifteen patients were partially dentate and 11 edentulous. The mean height of the alveolar ridge was 2.5 mm preoperatively (range 1–5.5 mm). 126 fixtures were inserted, 93 in grafted bone and 33 in alveolar bone. Twenty-two patients have been followed for three years, 21 for four years and 11 for five years. The clinical overall survival rate was 69.6% although only 61.2% in grafted bone. Ten of the patients had varying degree of sinusitis post-fixture installation. At the end of the study, 23 patients had permanent bridges. The survival rate was low for inlay supported implants when the one-stage surgical technique was applied. Two-stage surgery may be a safer method.RésuméUne étude prospective d’une chirurgie en une étape avec un transplant osseux intrasinusal et des implants a été effectuée chez 26 patients (treize hommes et treize femmes). Le but de cette étude a été d’évaluer le taux de succès dans un processus d’épaississement du plancher sinusal en une étape chez des patients qui nécessitaient un épaississement osseux du processus alvéolaire. Quinze patients étaient partiellement édentés et onze édentés. La hauteur osseuse restante était de 2.5 mm avant l’opération (1–5.5 mm). Cent vingt-six implants ont été insérés, 93 dans l’os greffé et 33 dans l’os alvéolaire. Vingt-deux patients ont été suivis pendant trois années, 21 pendant quatre années et onze pendant cinq ans. Le taux de survie général clinique était de 70% bien que seulement de 61% dans l’os greffé. Dix des patients avaient un degré variable de sinusite après le placement des implants. A la fin de l’étude, 20 patients ont pû obtenir des bridges permanents. Le taux de survie était bas pour les implants appuyés sur inlay lorsque la technique de chirurgie était effectuée en une étape. La chirurgie en deux étapes semblerait une méthode plus sûre.ZusammenfassungBei 26 Patienten (13 mnnliche und 13 weibliche) wurde eine prospektive Studie über die Anhebung des Sinus durchgeführt, bei welcher in einem einzigen chirurigischen Eingriff ein Knochentransplantat in den Sinus eingebracht und Implantate eingesetzt wurden. Es war das Ziel der Studie, die Erfolgsrate der Anhebung des Sinus in einem einzigen chirurgischen Eingriff bei Patienten, welche eine Augmentation des Alveolarfortsatzes benötigten, zu untersuchen. Fünfzehn Patienten waren teilbezaht und 11 waren zahnlos. Die mittere Höhe des Alveolarfortsatzes betrug vor der Operation 2.5 mm (Bandbreite 1–5.5 mm). Es wurden insgesamt 126 Implantate eingesetzt, 93 davon in transplantierten Knochen und 33 in bestehenden Alveolarknochen. Zweiundzwanzig Patienten konnten über 3 Jahre, 21 über 4 Jahre und 11 über 5 Jahre nachuntersucht werden. Die gesamte klinische Ueberlebensrate der Implantate betrug 69.6%, whrend die Ueberlebensrate im transplantierten Knochen lediglich 61.2% erreichte. Zehn der Patienten litten nach der Implantation an unterschiedlich ausgeprgten Sinusitiden. Beim Abschluss der Studie trugen 20 Patienten festsitzende Rekonstruktionen. Die Ueberlebensrate für die im Transplantat verankerten Implantate war tief, wenn die Behandlung in einem einzigen chirurgischen Eingriff durchgeführt wurde. Das Vorgehen in zwei chirurgischen Eingriffen könnte die sicherere Methode darstellen.ResumenSe llevó a cabo un estudio prospectivo de cirurgía de una sola fase con transplante de hueso intrasinusal e implantes en 26 pacientes (13 varones y 13 hembras). La intención del estudio fue evaluar el índice de éxito con el procedimiento de elevación del seno en una sola fase en pacientes con necesidad de aumento del proceso alveolar. Quince pacientes estaban parcialmente dentados y 11 edéntulos. La altura media de la cresta alveolar fue de 2.5 mm preoperatoriamente (rango 1–5.5 mm). Se insertaron 126 fijaciones, 93 en hueso injertado y 33 en hueso alveolar. Veintidós pacientes han sido seguidos durante tres años, 21 durante cuatro años y 11 durante cinco años. El indice total de supervivencia clínica fue del 69.6% aunque solo 61.2% en hueso injertado. Diez de los pacientes tuvieron diversos grados de sinusitis tras la instalación de la fijación. Al final del estudio 20 pacientes tenían puentes permanentes. El índice de supervivencia fue bajo para implantes colocados aplicando la técnica quirúrgica de una sola fase. La cirugía de dos fases puede ser un método mas seguro.
Clinical Oral Implants Research 09/2001; 12(5):479 - 487. · 2.51 Impact Factor
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ABSTRACT: The purpose of this study was to evaluate the outcome of the 3 different diameters of Brånemark System implants, with special focus on the 5.0-mm-diameter implant.
Ninety-eight patients (99 jaws) with a mean age of 62 years were included in this retrospective report. The mean follow-up period was 2 years and 8 months. A total of 379 Brånemark System implants (3.75 mm diameter, n = 146; 4.0 mm diameter, n = 76; 5.0 mm diameter, n = 157) were placed in 29 edentulous and 70 partially edentulous jaws.
Eight of the 146 implants in the 3.75-mm-diameter group failed (5.5%). The corresponding figures for the 4.0- and 5.0-mm-diameter implants were 3 of 76 (3.9%) and 7 of 157 (4.5%), respectively.
All failures were recorded in maxillae, ie, 18 of the 298 placed, and the majority of these were found in bone quantity group B and quality group 2. Only 3 implants of 131 failed in bone judged as quality 4. The marginal bone loss was low for the 3 implant diameter groups.
The favorable outcome in bone of poor quality is ascribed partly to the use of an adapted preparation technique and extended healing periods for achievement of the best primary and secondary implant stability possible.
The International journal of oral & maxillofacial implants 17(5):671-7. · 1.78 Impact Factor
