Bücher und Digitale Medien

Purpose: This study aimed to conduct a radiological and clinical evaluation of patients who underwent fixed rehabilitation involving subperiosteal implants and to define not only the criteria for failure but also the criteria for survival and success. Materials and methods: Patients suffering from severe atrophy of the maxilla and/or mandible underwent immediate loading with fixed full-arch prostheses supported by custom-made 3D-printed subperiosteal implants. The evaluated outcomes included the success and survival rates of subperiosteal implant prosthetic therapy, surgical complications, and the three-dimensional positions of osteosynthesis screws and sleeves used for implant adhesion to the bone. The SIO criteria (Stability, Inflammation, and Offset) were used for evaluating the success, survival, or failure of subperiosteal implant-prosthetic rehabilitation. Success required no clinical mobility, asymptomatic soft tissues without recession, and no intraoperative deviations from virtual implant planning; while survival allowed transient micromovements, tissue recession without inflammation, and minimal post-surgical implant modifications. Persistent micromotion and implant removal due to aesthetic dissatisfaction or fabrication of a new implant were classified as failures. Non-parametric tests were applied to the datasets with a significance level of p = 0.01. Eighteen patients were followed up for two years. Eleven implants were placed in the upper jaw and 15 in the lower jaw. Temporary instability was observed in four subperiosteal implants, accounting for a survival rate of 84.6% based on the Stability criterion). Two patients suffered from peri-implant soft tissue recession at two years (Inflammation criterion). Preoperative virtual implant positions and achieved postoperative position of 189 titanium osteosynthesis screws and sleeves were analyzed: 98 buccal, 69 linguopalatal, and 22 in other areas. The overall linear sleeve misalignment was 1.66±0.99mm. Horizontal misalignment (1.46±1.03mm) was approximately three times greater than vertical misalignment (0.59±0.21mm), with a significant difference (p value=0.0004). One patient exhibited horizontal and overall misalignments exceeding the maximum threshold suitable for implant success (approximately 5 mm), resulting in 25 successful and only one surviving implant (Offset criterion). No prosthesis failed during the entire follow-up, and no mechanical or functional complications were recorded. The cumulative survival rate was 100% at the two-year follow-up. Conclusions: The proposed SIO criteria defined success, survival, and failure for subperiosteal implant rehabilitation. Transient movements or infection events were classified as survival indicators, while negative Offset results led the implant survival but not success. The present virtual design and planning approach achieved a 73.1% success rate over two years according to the SIO classification. Schlagwörter: Stability-Infection-Offset criteria, subperiosteal implants, success code, fixed prosthesis, immediate loading

Ziel: Ziel dieser retrospektiven Studie war es, die klinischen Veränderungen und Dimensionsveränderungen des Weichgewebes nach Implantatinsertion in abgeheilte Zahnlücken und Sofortbelastung mit individuell vorgeformten bzw. konventionellen Gingivaformern über 3 Jahre zu untersuchen. Material und Methode: Prämolaren- bzw. Molarenimplantate wurden entweder mit individuellen provisorischen Gingivaformern, die im Sinne der biologisch orientierten Präparationstechnik (BOPT) keine Präparationsgrenze aufwiesen (Testgruppe), oder mit konventionellen Gingivaformern (Kontrollgruppe) sofortbelastet. Drei Monate später wurden die definitiven Kronen hergestellt. Ausgewertet wurden die Weichgewebeveränderungen als primäre sowie eventuelle unerwünschte Ereignisse als sekundäre Endpunkte. Ergebnisse: Von den insgesamt 87 ursprünglich eingeschlossenen Patienten wurden 50 für die retrospektive Analyse ausgewählt, davon 23 Patienten in der Test- und 27 Patienten in der Kontrollgruppe. Postoperativ traten in den ersten Tagen zwei Fälle von Mukositis, einer in jeder Gruppe, als unerwünschte Ereignisse auf. Zudem wurden einige wenige technische Komplikationen, darunter die Lockerung von vier verschraubten Kronen dokumentiert. In beiden Gruppen war während der ersten 3 Monate eine signifikante Zunahme der Alveolarkammbreite zu beobachten (Testgruppe: +2,5 ± 0,5 mm; Kontrollgruppe: +1,0 ± 0,9 mm), während sich zwischen den Breiten nach 3 Monaten und denen nach 3 Jahren in beiden Gruppen keine Veränderungen fanden. Ferner ergaben sich bezüglich der Breite der keratinisierten Mukosa keine signifikanten Differenzen zwischen den Baseline-Messungen und den Werten nach Abschluss der Nachbeobachtung. Der Papillenindex nach Jemt zeigte eine höhere Zunahme in der Test- als in der Kontrollgruppe. Schlussfolgerung: Über den 3-jährigen Beobachtungszeitraum waren an den mit individuellen Gingivaformern sofortbelasteten Implantaten bessere Ergebnisse bezüglich der Weichgewebedicke und Breite des keratinisierten Gewebes zu beobachten als an denen der Gruppe mit konventionellen Gingivaformern. Die Anzahl unerwünschter Ereignisse (Mukositis und Dehiszenz) war in beiden Gruppen annähernd gleich. Zudem führten individuelle Gingivaformer zu einer signifikanten Zunahme der Alveolarkammbreite, die hier doppelt so groß war wie in der konventionellen Gruppe. Schlagwörter: anatomisches Käppchen, Dentalimplantat, Gingivaformer, Implantatabutment, Implantatinsertion, individueller Gingivaformer

Purpose: To examine the remodeling process of both the soft and hard tissue components of the postextraction socket around immediately loaded dental implants after tooth extraction in maxillary esthetic areas. Materials and Methods: Subjects underwent immediate placement of single implants in postextraction sockets without bone grafting, and their immediate provisionalization with custom tooth-like interim crowns were fabricated using digital diagnostic impressions and a dental milling machine. Intraoperative and 1-year follow-up layered scans of the postextraction sockets after implantation were acquired using a 3D optical system. In the short term, subjects underwent computed tomographic scans. Digital impressions for gingival contours, originally stored as STL (standard tessellation language) files, were converted to DICOM (Digital Imaging and Communications in Medicine) files with the implant shoulder working as a referral point, which were then superimposed to 3D radiologic images. The observed volumetric and linear outcomes were measured using a program known as DentaScan. The width of the alveolar crest at the level of the implant shoulder and marginal bone levels were acquired. Nonparametric tests were applied with a level of significance set at P < .01. Results: No failure was reported after a follow-up of 1 year. Little or no inflammation of the treated areas was registered, and there were practically no signs of suppuration. The areas showed a significant reduction in the overall volumes for both soft and bone tissue, with a P value < .0001 from the baseline (0.983 ± 0.172 cm3) to the 1-year survey (0.865 ± 0.156 cm3). If the soft and bone tissue changes were separately evaluated, a significant loss (with a P value < .0001) was registered for only the bone tissues (from 0.434 ± 0.075 to 0.355 ± 0.061 cm3). Moreover, changes in gingival tissue from baseline to the 1-year survey (–0.040 ± 0.067) appeared to be significantly different from the overall volume loss (–0.118 ± 0.083 cm3). A shrinkage in width (–0.5 ± 0.7 mm) was found from baseline (12.6 ± 0.6 mm) to the 1-year follow-up (12.1 ± 0.9 mm). Marginal bone levels were 0.97 ± 0.70 mm and 0.39 ± 0.78 mm, respectively, at the mesial and distal aspects of the implants. Conclusions: The present analysis suggested that immediately customized provisionalization was effective enough to prevent both volume loss and linear shrinkage at the layers of the treated areas. Moreover, the buccal aspects seemed to be the areas most affected by the loss of volume. The mean loss in width, which amounted to roughly 0.5 mm, appeared to be negligible when compared to the overall width measured before surgery. Schlagwörter: alveolar remodeling, immediate implant, intraoral digital scanning, imaging superimposition, immediate provisionalization, computerized tomography

This study aimed to calculate the 3-year dimensional change in crestal bone width when dental implants placed in postextraction sockets underwent two alternative techniques for alveolar preservation. Fresh sockets that had undergone immediate implant placement were categorized into one of two groups depending on the procedure type. For the xenogeneic biomaterial grafted (BG) group, the gaps between the metallic implant surfaces and the bony walls were filled with corticocancellous porcine bone; in the anatomical cap group, in which patients were treated with guided tissue healing (GTH), cross-linkable acrylic resin caps were immediately screwed on the implants. Absolute measurements of the alveolar width were performed on 3D images acquired before tooth extraction (thereby ensuring correct surgical treatment) and 3 years after surgery. Nonparametric statistics were performed, with the level of significance set at 1%. The results of 46 implants (placed in 36 patients) were analyzed, and 100% survival rates were reported for both groups at 3 years postsurgery. Minor swelling of treated areas was observed the first few days of healing, but neither mucositides, dehiscence events, nor suppurations occurred. At 3 years postsurgery, loss in alveolar ridge width was higher for the BG group (-1.1 ± 0.6 mm) than for the GTH group (0.0 ± 0.3 mm); moreover, these changes were significantly different (P < .0001). This clinical and radiographic data analysis suggests that the implant sites that received a xenogeneic filling material were less effective in maintaining the preoperative alveolar bone width than sites that underwent GTH with immediate implants and anatomical tooth-shaped caps.

Purpose: To examine the short-term outcomes of maxillary sinus augmentations consisting of laterally and apically displacing the palatal wall through a transcrestal approach. Materials and Methods: The maxillary sinus floor was fractured in its palatal aspect by allowing a displacement in the buccal and apical direction with a magnetoelectric system. A medial displacement of the alveolar crest in its palatal bony plate was performed at the same time. Crestal bone change was investigated using superimposed preoperative and postsurgical computed tomography scans. Clinical and radiologic outcomes over 1 year were evaluated. Results: A total of 18 implants were selected for retrospective volumetric and linear analyses. Sinus floor and alveolar bone augmentation surgery led to a significant increase in the bone volume (P = .0002) from 0.134 ± 0.060 cm3 to 0.639 ± 0.166 cm3, with an overall gain of +0.504 ± 0.139 cm3. No part of the implant apices appeared to protrude into the maxillary sinus at the 1-year follow-up. The width of the alveolar crest changed from 5.1 ± 0.5 mm to 6.5 ± 0.7 mm, with a significant increase of +1.4 ± 0.6 mm registered at 1 year. However, a marginal bone loss of 1.0 ± 0.8 mm was observed. When tooth positions were investigated, no significant differences between the two groups (premolars versus molars) were found. Conclusion: Significant and effective bone gains allowed proper placement of the dental implants but with a minimal loss of peri-implant bone volume. Schlagwörter: bone displacement, computerized tomography image, dental implants, infracture technique, maxillary sinus

The present study evaluated the 2-year changes in soft tissue width after implant placement in healed sites, using two different methodologies to obtain tissue healing: preformed and anatomical abutment caps for customized healing (test) vs conventional healing abutments (control). The null hypothesis was that there would be no difference between the test group and the control group. Patients who suffered from a single-tooth edentulous area in the premolar/molar region were included. Both the standard abutments and the preformed and anatomical abutment caps were immediately screwed on the implants. The final crown restoration was fabricated 3 months later. Primary outcomes (changes in the alveolar soft tissue ridge) and secondary outcomes (testing adverse events and measuring implant/prosthesis survival) were evaluated. Thirty-nine patients (24 women) with a mean age of 57.7 ± 7.1 years (range: 42.6 to 72.8 years) were included. Alveolar widths in both groups showed significant increases from baseline to the 3-month follow-up, with augmentations of 3.6 ± 0.7 mm for the test group and 1.1 ± 0.9 mm for the control group. The gain in soft tissue appeared to be statistically different between the two groups (P < .0001). Contrarily, any subsequent change in width from 3 months to 2 years was negligible and insignificant (< 0.33 mm for both groups). The technique described in the present study encourages the potential for alternative healing based on the guided soft tissue concept, as it either eliminated the need for second-stage surgery or it reduced step-by-step peri-implant soft tissue conditioning, obtaining a tissue contour immediately very similar to that of a final prosthesis.

Purpose: This study aimed to test the effectiveness and reliability of the alveolar ridge-splitting technique in atrophic posterior arches, investigating the middle-term volumetric and clinical outcomes. Materials and methods: Atrophic alveolar ridges in the maxillary and mandibular posterior areas were treated with the alveolar ridge-splitting/expansion technique (ARST), immediate implant placement, collagen sponges covering the defect, and healing by secondary intention. Areas were rehabilitated by fixed dental prostheses supported by dental implants. Changes in volume and width of the alveolar ridge were retrospectively calculated by comparing the x-ray tomography scans obtained before and 5 years after surgery. Report of failure in the case sheets was taken into account. Cross-sectional images were also used to assess the thickness of the labial alveolar plates at the implant shoulder. Nonparametric analyses of variance with post hoc and pair-comparison tests were performed with a level of significance of .05. Results: A total of 38 patients were retrospectively selected (23 women and 15 men). Six patients underwent ARST surgeries in both the maxilla and the mandible and were excluded from statistical analysis. Differences between 16 maxillae and 16 mandibles and between 12 single crowns and 20 fixed partial dentures (FPDs) were searched. Episodes of minor swelling occurred within the first 2 days after surgery. Neither mucositis nor flap dehiscence had been registered. The mean values of buccal cortical thickness were 2.46 ± 0.49 mm and 1.15 ± 0.33 mm, respectively, in the maxillary and mandibular areas. After 5 years of survey, maxillary increases in alveolar ridge width and volume were +4.4 ± 0.4 mm and +295 ± 45 mm³, respectively, whereas the same outcome variables (+3.5 ± 0.7 mm and +217 ± 53 mm³) measured in the mandible appeared to be significantly smaller than those in the maxilla (P < .0001). One maxillary single implant failed. Cumulative survival rates at 5 years were 100% for mandibles and 95.5% (95% CI: 86.8% to 100%) for maxillae. Conclusion: Posterior areas of the maxilla displayed a higher increase in alveolar width and volume than mandibular areas, and even if it would be premature to draw survival conclusions at this stage without any statistical support, a lower cumulative survival rate was reported for the maxillary single implants. Schlagwörter: alveolar ridge split, alveoloplasty, bone remodeling, posterior mandible, posterior maxilla, secondary intention healing

Purpose: This study aimed to report a practicable and noninvasive two-stage technique for sinus elevation and delayed implant insertion in the augmented site with residual bone height down to 3 mm or even lower. Materials and methods: The surgical technique employed a two-stage process for rehabilitation of posterior maxillary single-tooth edentulous areas, involving, in the first step, transcrestal maxillary sinus floor augmentation with a collagen sponge to fill the intrabony cavity resulting from the detachment of the sinus membrane; the second step consisted of another indirect sinus floor elevation using magnetoelectric surgery with immediate implant placement and no grafting material. Changes in bone height were evaluated by a comparison of the computed tomography scans acquired before treatment and after surgery (at 3 months and 5 years of the survey). Statistically significant differences between the times and the tooth sites were evaluated by nonparametric statistics (matched and independent), with P < .01. Results: Forty patients were retrospectively selected. The preoperative height of the available alveolar bone was 2.9 ± 0.6 mm. A significant increase in bone height (P < .01) was found for both the first and the second surgery (3.1 ± 0.6 mm and 4.4 ± 0.6 mm, respectively). The overall bone height was measured at 3 years after the first surgery (10.3 ± 0.6 mm). Measurements of the bone height ranked for tooth positions showed no significant difference between premolars and molars. None of the selected patients registered an implant failure. Conclusion: Two-stage osteotome-mediated sinus elevation appeared to be a predictable technique that enabled practitioners to increase the bone height and to obtain successful outcomes even if the amount of bone was approximately 3 mm in height. Schlagwörter: CBCT, dental implant, osteotome sinus elevation, single crown, two-step technique

Purpose: The purpose of this study was to compare success and outcomes among implants positioned either in grafted or ungrafted alveoli during 10 years of follow-up. Materials and Methods: This retrospective analysis was conducted on data of subjects who underwent tooth extraction and alveolar ridge preservation. Sites, one per patient, were ranked into three groups: postextraction ungrafted alveoli, and postextraction grafted alveoli with either synthetic magnesiumenriched hydroxyapatite or porcine bone. An absorbable collagen sheet was used to completely cover all the sockets. A secondary intention healing was sought for all procedures. Data regarding implant survival and marginal bone loss around implants were gathered until the 10-year follow up. Pairwise comparisons were performed with nonparametric tests, and statistical significance was set at .01. Results: Sixty-three subjects were included: 42 implants (19 and 23 in the magnesium-enriched hydroxyapatite and porcine bone groups, respectively) placed in grafted sites and 21 in nongrafted sites. The success rate of the grafted groups was 88.1% (CI: 78.3% to 97.9%) at the 10-year follow-up. On the other hand, in the ungrafted group, the overall success rate was 85.7% (CI: 70.8% to 100%). Peri-implant marginal bone loss at the 10-year follow-up for the magnesium-enriched hydroxyapatite group was 1.2 (0.7) mm, while for the porcine bone group, it was close to 0. The behavior of the ungrafted group appeared to be significantly different compared with both grafted groups; however, marginal bone levels ranging from 0.1 to 0.4 mm were observed from 3 to 10 years. Conclusion: A difference in terms of long-term success rates between grafted and ungrafted sites was not revealed. Bone loss was significantly higher in the magnesium-enriched hydroxyapatite grafted group compared with those in the other groups (without or with other bone substitute material). Schlagwörter: bone graft, bone substitute, soft tissue management

Ziel: Ziel war eine Untersuchung des Verlustes an Alveolarkammbreite drei Jahre nach Implantation in frische Extraktionsalveolen für zwei Gewebeheilungstechniken: konventionelle Heilung vs. Heilung mit einem CAD/CAM-gefertigten individuellen Gingivaformer. Material und Methoden: Sofortimplantate wurden in Extraktionsalveolen eingesetzt, ohne dass die Spalträume zwischen der Implantatoberfläche und den Alveolenwänden aufgefüllt wurden. Retrospektiv wurden Stichprobenimplantate (ein Implantat pro Patient) entsprechend dem Einheilungsverfahren in zwei Gruppen aufgenommen: Implantate in der konventionellen Gruppe heilten nach dem klassischen geschlossenen Verfahren mit Deckschraube ein, während in der individuellen Gruppe sofort ein CAD/CAM-gefertigter Gingivaformer auf das Implantat geschraubt wurde, der die Form des extrahierten Zahns imitierte. Die Breite des Alveolarkamms wurde auf 3-D-Röntgenbildern für die Ausgangssituation (vor der Operation) und die Situation drei Jahre postoperativ bestimmt. Die Auswertung erfolgte mittels parameterfreier Statistik bei einem Signifikanzniveau von 0,01. Ergebnisse: Insgesamt wurden 54 Implantate ausgewählt. Für die Gesamtheit der inkludierten Implantate lag die Überlebensrate nach 36 Monaten bei 100 %. Drei Jahre nach der Implantatsetzung wurde der Verlust an Knochenbreite in der konventionellen Gruppe mit 2,2 (1,1) mm und in der individuellen Gruppe mit 0,2 (0,7) mm gemessen. Die Veränderung der Knochenbreite war in der individuellen Gruppe signifikant geringer als in der konventionellen. Signifikante Unterschiede zwischen beiden Gruppen wurden auch für die einzelnen Zahnpositionen ermittelt: Der Verlust an Knochenbreite (von Schneidezahn bis Prämolar) war in der individuellen Gruppe mit Werten zwischen 0,2 und 0,4 mm zu vernachlässigen, während in der konventionellen Gruppe an allen Zahnpositionen eine umfangreiche Schrumpfung auftrat (mit Knochenverlusten im Bereich von 1,6 bis 3,0 mm). Schlussfolgerung: Der CAD/CAM-Ansatz könnte folgende Vorteile bieten: 1.) Stabilisierung der Gingivasituation und des Knochenvolumens an Sofortimplantaten, 2.) Beibehaltung des Emergenzprofils des natürlichen Zahns für die prothetische Krone und damit Vermeidung einer zahntechnischen Extrapolation des Emergenzprofils der definitiven Restauration sowie 3.) optimale prothetisch-chirurgische Planung und minimalinvasive Extraktion mit Erhalt der Integrität der Stützgewebe. Schlagwörter: Dentalimplantat, Sofortimplantation, Abutment, individueller Gingivaformer, digitale Volumentomografie