Purpose: To evaluate the correspondence between output from a new artificial intelligence tool (AIT) and clinician evaluation regarding the immediate loading suitability of dental implants based on insertion torque curves recorded during implant placement in an in vitro test. The secondary aim was to analyze peak insertion torque (PIT) and variable torque work (VTW) values of the implants. Materials and Methods: The study was performed with four different densities of artificial bone blocks of solid rigid polyurethane without a cortical layer. Five types of implants with different macrogeometries were used. A total of 140 implants (7 implants of each type in the four polyurethane blocks) were inserted. Immediately after implant placement, the insertion torque curves were classified by the operator as suitable (S) or nonsuitable (NS) for immediate loading. The same curves were then analyzed by the new AIT, which classified them as belonging to the “YES” or “NO” class. For each implant, PIT and VTW values were also recorded. Results: The correspondence between clinician and AIT evaluation was 99.3%, with only one false negative reported by the algorithm analysis. The AIT was found to have a sensitivity of 98.95%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 97.8%. Mean PIT of the whole sample was 34.19 ± 19.43 Ncm, while mean VTW was 2,266.89 ± 1,993.73 Ncm. Statistically significant differences were found between implant systems in the whole sample and according to density of the polyurethane block. Conclusions: The AIT showed a high level of accuracy in the prediction of immediate loading suitability of dental implants based on the provided insertion torque curves. All the implants used in the in vitro test achieved good levels of primary stability, except when inserted in the least-dense polyurethane block. Clinical studies conducted with larger samples and more clinicians are necessary to confirm these results. 

Purpose: To evaluate primary stability of a new dental implant design in low-density bone sites, compare it with another implant design previously studied in the same bone density, and explore possible correlations between primary stability parameters. Materials and Methods: The study was carried out on fresh humid bovine bone classified as type III. The test group consisted of 30 DS Prime Taper implants (PT), and the control group consisted of 30 Astra Tech EV implants (EV). All the implants were inserted according to the protocol provided by the manufacturer. After placement, variable torque work (VTW), peak insertion torque (pIT), and resonance frequency analysis (RFA) were recorded. Results: Mann-Whitney test showed that the mean VTW and pIT were significantly higher in the test group PT compared to the control group EV; furthermore, statistical analysis showed that the mean RFA was slightly higher in the control group EV but without reaching statistical significance. Pearson correlation analysis showed a very strong positive correlation between pIT and VTW values in both groups; furthermore, it showed a positive correlation between pIT and RFA values and between VTW and RFA values again in both groups. Conclusion: The results showed that the novel tapered implants were able to reach good primary stability in low-density bone sites and that this was superior to parallel-walled implants when measured with VTW and pIT. Moreover, a statistically significant correlation was found between the three methods used to measure implant primary stability. Keywords: insertion torque, primary stability, resonance frequency analysis, tapered implants, variable torque work

Purpose: To provide a 1-year assessment of friction-retention abutments used to retain a single lithium disilicate (LS2) monolithic restoration. Materials and Methods: A total of 522 implants were placed to treat a mandibular or a maxillary single-tooth premolar or molar edentulous site. Three types of implants were used. The tested abutments were connected 3 months after implant placement. A single pressed LS2 monolithic restoration was cemented to a dedicated titanium cap and engaged to the abutment without the use of screws or cement. Any complications affecting the restoration or the opposing dentition, any soft tissue dimensional changes, the distance between the implant platform and the bone peak, and pocket probing depths were recorded at the time of restoration placement (T0), after 6 months of function (T1), and after 1 year of function (T2). Esthetic, functional, and biologic parameters were recorded at T0 and T2. Results: A total of 507 patients (284 women and 223 men) received a restoration at T0, and 504 reached the 1-year follow-up at T2. One restoration fractured after 10 months in function. No statistically significant differences were seen in the soft tissue measurements or in the measurements of the distance between the supporting implant platform and the bone peak. None of the restorations detached during the observation period. Conclusion: The friction retention abutment is a viable option to retain an implantsupported monolithic LS2 glass-ceramic restoration in cases of premolar or molar single-tooth edentulism.

Conical retention with antirotational features (Acuris abutment) has been recently proposed for restorations of healed single implants. The conometric abutments use the retentive force of the coping-abutment system to retain the prosthetic crown without the use of cement or screws. This retentive force must be overcome to obtain detachment of the relined provisional crown in immediate restorations. The present article describes the use of digital scanning technology to virtually plan computer-guided implant placement and restoration with conical indexed abutments in postextraction sites. Importing the scan data of both matrix and patrix abutments that are seated on the definitive cast into the computer-aided design software provides a workflow to preoperatively mill a crown that perfectly fits the abutment into the postextraction site. This technique simplifies the provisional crown relining onto the conometric indexed abutment and reduces the intraoperative time.

Purpose: To evaluate the 2-year performance of definitive implant- or tooth-supported three-unit fixed dental prostheses made of zirconia-reinforced lithium silicate placed to restore premolars and molars in clinical cases of partial edentulism. Materials and Methods: All patients received a three-unit fixed restoration made of monolithic, hot-pressed, zirconia-reinforced lithium silicate glass-ceramic. The restoration was cemented to two natural teeth or attached to two 3.5- or 4.5-mm–diameter square threaded, gritblasted, acid-etched integrated implants with a Morse taper connection. Peri-implant pocket depth and bone and soft tissue remodeling were recorded for 2 years at each follow-up visit. Esthetic, functional, and biologic United States Public Health Services (USPHS) parameters modified by the World Dental Federation study design were assessed yearly until the final follow-up appointment. At the time of placement of the definitive restorations and at the 2-year follow-up visit, the opposing dentitions were identified by type of restoration and supporting structures. Results: A total of 100 patients were consecutively enrolled in the period between June 2016 and July 2017, and 50 patients each received an implant-supported restoration (Group A) or a tooth-supported restoration (Group B). One (2%) of the 50 implant-supported prostheses fractured after 21 months of function. None of the other prostheses failed or became loose or detached. No significant differences involving probing levels or bone and soft tissue remodeling were found between the follow-up times. No cases of inflammation or infection of the mucosal cuff around the neck of the implants were recorded. The most common issue occurred immediately after placement of the prosthesis, when 3 patients (6%) from Group A and 4 patients (8%) from Group B asked for a modification of tooth shade. Conclusion: Implant-supported or tooth-supported three-unit fixed dental prostheses made of zirconia-reinforced lithium silicate can be used to successfully restore cases of posterior partial edentulism. The 2-year results of this report will be studied more in depth in ongoing long-term research.

For decades, the histologic evidence about osseointegration and the bone-implant interface has been discussed in the literature. In this review, the effectiveness of dental implants retrieved for different causes was evaluated. A literature search was performed in databases for papers about implants retrieved from humans published by the Implant Retrieval Center of the University of Chieti-Pescara, Italy. Sixty-eight articles were selected into categories based on topics. The data indicated high level of bone-toimplant contact, lamellar bone close to the surface, roughness related to an increased bone response, organized and remodeled bone after loading, and peri-implant interfaces subjected to a continuous dynamic function.

Aim: The goal of this case series was to evaluate the clinical outcome at the 2-year follow-up of immediately loaded combined screw- and conometric-retained implant-supported full-arch restorations virtually planned using digital scanning technology. Materials and methods: This series included 12 patients presenting hopeless teeth in the maxilla treated with computer-guided flapless implant placement. A total of 72 implants were inserted. All implants were immediately loaded with a complete-arch restoration supported by an intraorally welded framework. Digital scanning technology was used to virtually plan a combined screw and conometric retention of the frameworks. Clinical parameters were assessed at 1 week and at 1, 3, 6, 12, and 24 months follow-up. Results: The survival rate after 2 years was 98.6%, as one implant failed during the osseointegration period. No major prosthetic complications were observed such as issues with mobility, unscrewed abutments, disconnected conometric copings, and prosthetic fracture. Only one patient registered the chipping of a prosthesis. Conclusion: Based on the results of the present study, the use of combined screw and conometric retention for fixed immediate restorations properly planned using digital scanning technology seems to be a viable treatment alternative to screw or conometric retention alone for immediately loaded rehabilitations. Keywords: conometric retention, screw-retained, fixed dental prostheses, computer-guided surgery, computer-aided implantology, 3D optical scanning

Kürzlich wurde die schrauben- und zementfreie Retention implantatgetragener Restaurationen mithilfe einer Konus-in-Konus-Verbindung zwischen dem Abutment und einer korrespondierenden Kappe vorgeschlagen. Dieser als Konometrisches Konzept bezeichnete Ansatz dürfte zu einem Umdenken bezüglich klassischer Standards der präzisen Verbindung zwischen einzelnen Restaurationskomponenten führen, da mithilfe vorgefertigter Komponenten eine überlegene Passung zwischen dem Abutment und der Restauration erreicht wird. Hinzu kommt, dass Restaurationen dieses Typs keine Löcher aufweisen, wie sie bei verschraubtem Zahnersatz benötigt werden, und sich mit einem Kronen- bzw. Brückenentferner leicht wieder abnehmen lassen. Zudem kann der Restaurationsrand intrasulkulär platziert werden, ohne dass die Gefahr von subgingivalen Zementresten am Spalt zwischen Abutment und Gerüst besteht. Dieser Artikel fast die Grundprinzipien des neuen Konzeptes zusammen und zeigt auf, inwieweit es einen Paradigmenwechsel bei der Retention von implantatgetragenem Zahnersatz darstellen kann. Manuskripteingang: 09.10.2019; Annahme: 07.11.2019 Keywords: Implantatgetragener Zahnersatz, Implantatkrone, konometrisch, Konusverbindung, Teleskopkrone, spaltfreie Restauration

The use of the cone-in-cone connection to support definitive restorations was previously evaluated in cases involving full-acrylic resin or hybrid acrylic-resin composite prostheses. The aim of this study was to evaluate the performance of definitive fixed partial prostheses made with monolithic zirconia and supported by cone-in-cone abutments and integrated implants. Implants were placed into healed sites and fresh extraction sockets. The prostheses were placed in the posterior regions of partially edentulous patients after healing periods of 3 months. A total of 76 patients received fixed monolithic zirconia restorations splinted with cone-in-cone connections to two implants that were followed up yearly for 5 years. At each follow-up visit, peri-implant bone levels and pocket depths were recorded. Esthetic, functional, and biologic United States Public Health Services parameters modified by the World Dental Federation study design were assessed at the last follow-up appointments. The opposing dentition was categorized by type of restoration and supporting structure at the time of placement of the definitive zirconia partial restoration and at the 5-year follow-up. The treatment achieved an 88.2% success rate and a 97.4% survival rate at the 5-year follow-up. None of the prostheses became loose or detached. One fixed prosthesis (0.76%) fractured 41 months after placement. No significant difference involving peri-implant bone and probing levels between the experimental times was found. The results of this research indicated that abutment-prosthesis cone-in-cone connections were successful within the 5-year study period.

The aim of this study was to analyze the degree of mineralization around nine clinically stable titanium dental implants retrieved after 2 months to 17 years for mechanical complications from five patients. The micromorphology and microchemistry of the interface bone at the coronal and apical sides of the threads were analyzed by environmental scanning electron microscope and energydispersive X-ray spectroscopy (EDX) on histologic samples. Mineralization was investigated by atomic calcium-to-nitrogen (Ca/N), phosphorous-to-nitrogen (P/N), and calcium-to-phosphorous (Ca/P) ratio evaluation (statistical analysis by two-way analysis of variance with Student-Newman-Keuls; P .05). EDX showed higher Ca/N, P/N, and Ca/P values for the bone at the coronal side compared to the apical side of the threads in the long-term (≥ 14 years) samples. The two most significant findings were that (1) the interface bone located at the coronal side of the implant threads was generally more mineralized than the interface bone located at the apical side, and (2) the mineralization of the peri-implant bone at the interface increased over time. A higher degree of mineralization was found at 2 months in an immediately loaded implant when compared to the 2-month submerged unloaded control, likely related to the different remodeling events (coronal vs apical side of the implant threads) due to the direction of the loading forces.