International Journal of Implant Dentistry最新文献

Introduction: This study identifies current practices, patient management concepts and innovations in alveolar ridge augmentation (ARA) in Oral and Maxillofacial Surgery (OMFS) in Germany.

Material and methods: A survey with a dynamic online questionnaire with up to 40 questions was designed to collect general and specific data on ARA, such as case numbers, imaging, surgical techniques, (bio-)materials, and case management in OMFS. After internal and external validation, 1863 OMF surgeons within the German Association for Oral and Maxillofacial Surgery (DGMKG) were invited via email to participate. Data management was anonymized and descriptively.

Results: 324 OMF surgeons participated in the study (response rate 17.39%). Most participants (60.8%) work in private practices without inpatient care. 62.03% of participants insert > 200 implants, and 28.70% perform > 200 ARA annually. About 30.86% also provide implant-based prosthetic restorations. Cone-beam computed tomography (CBCT) is the imaging method most preferred by 87.74% of participants. The most common ARA techniques are external and internal sinus lift (SL) and bone block augmentation (97.31%, 90.57%, and 73.4%, respectively). Intraoral harvested autogenous bone grafts (ABG) are most commonly used for ARA (96.63%). The oblique line is the participants' preferred donor site for ABG (93.27%). ABG and xenogeneic bone substitutes are the most frequently used graft combinations (72.73%). Platelet-rich fibrin (PRF) is used by 58.59% of participants for ARA, mostly in SL procedures (76.44%). PRF is the most common substitute used to biofunctionalize biomaterials (48.16%). Oral antibiotics are used by 86.40% pre-/intraoperatively and by 88.97% postoperatively for ARA. Most participants believe the surgical technique (94.49%) and the surgeon's experience (92.28%) are the most critical factors for ARA success. 46.32% of participants aim to perform ARA within the skeletal envelope.

Conclusion: The findings highlight current practices, patient management, and innovations in ARA in OMFS in Germany. They show standard practices and numerous variations in several aspects.

Clinical relevance: Surgical technique, experience, patient health and compliance are relevant ARA success factors. This underlies the importance of extended surgical training and careful patient selection.

Purpose: Patients with pre-existing medical conditions that impair bone integrity face challenges in dental implant success due to compromised osseointegration. This study evaluates three titanium interconnected porous architectures: the TPMS solid gyroid, TPMS sheet gyroid, and Voronoi stochastic lattice. We aim to assess manufacturability, design controllability, and cellular interactions to identify an optimal architecture that enhances cellular behavior with the potential to strengthen bone-to-implant contact.

Methods: Three porous architectures were designed and compared: the two variants of the uniform, periodic triply periodic minimal surface (TPMS) gyroid, and the random, non-uniform Voronoi stochastic lattice. The porous constructs were fabricated using selective laser melting (SLM) and evaluated using microcomputed tomography (microCT) for porosity, manufacturability, and permeability. In vitro experiments used primary bone marrow stromal cells (BMSCs) isolated from 8-week-old wild type C57BL6/J mice. These cells were seeded onto the SLM-fabricated porous architectures and evaluated for adhesion using scanning electron microscopy (SEM) and RNA extraction. Cell trajectory was profiled using fluorescent confocal microscopy.

Results: Selective laser melting (SLM) successfully fabricated all three porous architectures, with the TPMS solid gyroid exhibiting the highest manufacturing resolution, controllability, and the most uniform pore distribution. Computational fluid dynamics (CFD) analysis showed that its permeability outperformed both the TPMS sheet gyroid and stochastic Voronoi architectures. In vitro cell culturing demonstrated superior cell behavior in the TPMS solid gyroid scaffold. RNA quantification after 72 h of culture showed that cells are most adherent to the TPMS solid gyroid, demonstrating a 4-fold increase in RNA quantity compared to the fully dense (control). Additionally, cell trajectory analysis indicated enhanced cell infiltration and cellularization within the pore channels for the TPMS solid gyroid architecture.

Conclusion: This research demonstrates that inducing an interconnected porous architecture into a titanium construct enhances cellular behavior compared to a traditional dense implant. The TPMS solid gyroid architecture showed superior manufacturability, making it a promising solution to improve dental implant success in patients with compromised bone integrity.

Purpose: This study aims to investigate the distinct behaviors of single-species and dual-species biofilms formed by Streptococcus sanguinis and Aggregatibacter actinomycetemcomitans on different titanium and implant surfaces. Four types of surfaces were examined: two clinically used implant surfaces, a super-polished surface and a sand-blasted surface of grade 4 titanium.

Methods: Specimens were incubated with single- and dual-species biofilms for 24 h. Biofilm formation was determined based on the amount of total DNA extracted from the bacteria. In order to specifically determine the biofilm formation of Streptococcus sanguinis, qPCR experiments were carried out. Staining followed by fluorescence microscopy was employed to verify the efficiency of the washing steps.

Results: Biofilm formation by single- and dual-species cultures was observed on all tested implant surfaces. However, a clear influence of surface characteristics on biofilm formation could not be conclusively demonstrated. Mixed cultures of S. sanguinis and A. actinomycetemcomitans (AAC) exhibited increased biofilm formation through the enhanced DNA amount of S. sanguinis. In contrast, this effect was not observed in dual-species cultures of Staphylococcus epidermidis and S. sanguinis.

Conclusion: AAC promotes biofilm formation of S. sanguinis, highlighting the significant role of AAC in enhancing biofilm development. Conversely, a definitive conclusion regarding the correlation between titanium implant surface roughness and biofilm formation was not possible. However, our results suggest a tendency that dual-species biofilm formation may be influenced by surface structure.

Purpose: The objective of this study was to investigate the primary stability of zirconia implants using varying drilling protocols, with a focus on the impact of thread cutting on insertion torque in both mixed (D2/D3) and soft (D4) bone types. The study aimed to evaluate whether reducing thread cutting could increase insertion torque and consequently improve primary stability.

Methods: Four drilling protocols were developed, each varying in the degree of thread cutting: no thread cut, one-third thread cut, two-thirds thread cut, and full thread cut. Implants were placed into fresh porcine hip and tibia bones simulating D2/D3 and D4 bone. The protocols followed each implant system's manufacturer recommendations. Insertion torque was measured using a torque indicator, and statistical analysis was conducted with the Mann-Whitney U test, with p < 0.05 considered statistically significant.

Results: Significant differences in primary stability were observed between implant systems and drilling protocols, particularly in D4 bone. Three of the four implant systems showed improved primary stability in D4 bone when the thread cut was reduced (p < 0.05). One system achieved the recommended insertion torque with a full thread cut. In contrast, in D2/D3 bone, all implant systems required a full thread cut to remain within the manufacturer's torque guidelines.

Conclusions: Zirconia implant systems exhibit substantial variability in primary stability based on the selected drilling protocol and bone quality. Reducing thread cutting demonstrated improved stability in soft bone. However, excessive torque should be avoided to prevent mechanical failure, especially in systems with lower fracture resistance.

Background: The objective of this study was to evaluate differences in the intra-implant distance, inter-implant distance, intra-implant axis and inter-implant axis of two different intra-oral scan bodies (ISBs) which are connected to three implants in a curved line by comparing laboratory scanner (LBS) versus an intra-oral scanner (IOS).

Methods: Printed model with three internal hexagon implant analogs at the locations of 12#, 13#, and 14# was produced. Two ISBs, MIS Dentsply Sirona (MIS) and Zirkonzhan (ZZ), with different geometries (MIS trapezoid, ZZ cylindrical) were scanned one time by using LBS (master model) followed by thirty scans with IOS. After each scan a stereolithography (STL) file was produced and each IOS STL file was superimposed with the LBS STL file (master model) by using three-dimensional (3D) analysis software PolyWorks^®2020. A Kolmogorov-Smirnov test was performed followed by a Mann-Whitney test (p < 0.05).

Results: Mean errors for inter-implant distance were significantly lower for MIS compared to the ZZ (p < 0.05). In contrast, mean errors for intra-implant angle were significantly lower for ZZ compared to MIS (p < 0.05). Mean error for inter-implant angle was significantly lower for MIS compared to ZZ only between 12# to 14# and no difference was found between the other couples (p < 0.05).

Conclusions: ISB geometry influenced all four parameters: intra-implant distance, intra-implant angle, inter-implant distance and inter-implant angle. MIS ISB trapezoid geometry resulted significantly lower mean error regarding most parameters except intra-implant angle. ZZ ISB cylindrical geometry had a good impact only on the intra-implant angle.

Purpose: The aim of this study was to investigate the superimposition of CBCT data with virtual models of the oral situation directly generated using an IOS and with indirectly generated plaster models.

Methods: Two different radiopaque jaw models were first scanned using a CBCT unit. Secondly, ten scans using an IOS and ten alginate impressions were made. The alginate impressions were cast with plaster and the plaster models were digitized using a laboratory scanner. Virtual Reference models generated with an industrial scanner were superimposed with the data sets of the virtual models using both a best-fit procedure on the palate and on the teeth. Deviations in two toothless areas were statistically evaluated.

Results: The superimposition of the directly generated models with the CBCT-based datasets showed lower deviations. Lower deviations were also calculated for the best-fit based on the teeth. The lowest deviations were found for model 1 with direct modeling and superimposition over the teeth with 0.008 mm (indirect: 0.210 mm; P = 0.001) and for model 2 with 0.010 mm (indirect 0.106 mm; P = 0.002).

Conclusions: Virtual models of the oral situation generated directly using an IOS are better suited for superimposing with CBCT-based datasets than indirectly generated ones. The best-fit on the teeth is superior to that on the palate.

Purpose: This study aimed to compare the accuracy of immediate implant placement (IIP) with different implant macrogeometry using a dynamic navigation in the maxillary aesthetic zone.

Methods: Seventy-six extraction sockets in the maxillary aesthetic zone from nineteen partially edentulous models were randomly divided into four implant system groups with different macrogeometry: non-progressive and trapezoidal (NP-T), progressive and trapezoidal (P-T), progressive and V-shaped (P-V), progressive and spiral (P-S). The coronal, apical, and angular deviations of the fully guided implants with navigation were measured and compared among different groups.

Results: Significant differences were detected in coronal, coronal buccolingual, coronal depth, apical, apical buccolingual, and apical depth deviations among the four groups (p = 0.035, p = 0.001, p = 0.004, p = 0.047, p = 0.007, p = 0.004, respectively). The P-V group demonstrated minimal coronal and apical buccolingual deviations (mean ± SD: 0.06 ± 0.35 mm and 0.00 ± 0.42 mm, respectively) for IIP with the guidance of dynamic navigation.

Conclusions: With the limitation of the in vitro study, different microgeometry of implants might influence the accuracy of IIP in the maxillary aesthetic zone with dynamic navigation. Implants with progressive and V-shaped thread designs perform best in reducing buccolingual deviations.

Purpose: The aim of this study was to evaluate the marginal bone loss (MBL) over a follow-up period of up to 36 months in Immediate dental implants (IDIs), as well as the impact of various clinical variables on the MBL.

Methods: IDIs placed in two surgical phases were evaluated. Implants were classified into bone loss (BL, exposed threads), bone remodeling (BR, crestal bone at the implant margin ± 0.1 mm), and bone overlapping (BO, bone above the abutment).

Results: A total of 1,040 IDIs were inserted in 344 patients with a successful osseointegration rate of 98.9%. The average MBL at 2, 6, 12, 24, and 36 months was - 0.3 ± - 1.0 mm, - 1.1 ± -1.8 mm, - 1.4 ± - 1.8 mm, - 1.7 ± - 1.9 mm, and - 1.3 ± - 2.3 mm, respectively. In the Baseline-12-month period, 17.5% of the IDIs presented BL, 9% BR, and 73.5% BO. For the B1-12 month period, 19.8% presented BL, 10.7% BR, and 69.5% BO. Mixed regression models showed significant MBL overtime pre-loading (p < 0.0001), stabilizing at 8.5 months from implantation. Immediate mandibular implants had lower MBL (p = 0.0365). Post-loading, MBL was lower in the mandible (p = 0.0095) and positively influenced by abutment height and rotational abutments.

Conclusions: The present study supports the clinical efficacy of the IDIs placement protocol with high survival rates and acceptable MBL. It is recommended to place bone level implants slightly below the crest to ensure the platform remains at an optimal depth during the initial bone remodeling phase post-implantation.

Purpose: The aim of this study was to investigate the effect of different bone graft hydration times on bone regeneration.

Methods: Five-mm defects were created on either side of the sagittal plane in the calvaria of 40 rats. In each rat, the right and left defects were filled with allograft (Cenobone^®) and xenograft (Cerabone^®) particles, respectively, based on the grouping that was randomly assigned in the study (no hydration of bone graft, 2-minute saline hydration, 10-minute saline hydration, 30-minute saline hydration, and 2-minute blood hydration). Histological and histomorphometrical analyses were performed eight weeks after surgery. The amount of new bone formation, remaining graft, and connective tissue were analyzed using the general linear model (GLM) and Bonferroni test.

Results: There was no significant difference regarding the mean of new bone, remaining graft, and connective tissue between the xenograft samples in different hydration groups. In the allograft groups, the mean new bone formation of the no-hydration and 2-minute saline-hydrated groups was significantly lower than 30-minute saline-hydrated and blood hydrated groups (P = 0.03 and P = 0.03, respectively). Regarding the variable of the remaining graft particles, the results were almost similar.

Conclusions: The results of this study showed that, the method of bone graft hydration before it is used in treating bone lesions affects osteogenesis. Especially in the case of allograft, rehydration before usage at least for 10 min is recommended.

Purpose: The aim of this study was to investigate the performance of a novel 3D-printed cooling system for drilling templates during fully guided implant insertion.

Methods: Dental implant tunnel preparations were performed for the Straumann Bone Level implant in a 3D-printed synthetic resin model using either conventional guided or modified 3D-printed guided (with a cooling channel leading directly to the implantation site) drilling templates. Temperature measurements were performed with and without cooling at drill depths of 2, 4, 7, and 10 mm.

Results: For all drill depths and templates, cooling had a statistically significant (p < 0.001) influence on the measured mean temperature. ANOVA and Bonferroni correction revealed that there was a statistically significant (p < 0.001) difference in the cooling efficiency of the samples cooled with all the templates in comparison with that of the samples not cooled. The maximum temperature measured with the conventional template was 35.2° without cooling and 26.6 °C with cooling at depths of 2 and 10 mm, respectively. For the modified template, the maximum temperature reached 39.1 °C without cooling and 31.2 °C with cooling at depths of 10 and 2 mm, respectively.

Conclusions: Compared with the conventional cooling system, the newly developed internal cooling channel of the modified drill template did not lead to a better cooling effect.