Three‐Unit Prosthesis Supported by a Single Implant With Two Cantilever Extensions in the Posterior Region (T‐Bridge): Case Report With a 2‐Year Follow‐Up

To evaluate clinical, clinician- and patient-reported outcomes (PROs) of two adjacent single posterior implants immediately loaded with definitive single crowns up to 1 year. Ten patients in need of two adjacent posterior single implants were included. All implants were placed applying a fully digital workflow. Definitive screw-retained single zirconia crowns were delivered within 72 h after implant placement. Clinical parameters, patient- and clinician-reported outcomes were assessed up to 1 year of follow-up. Clinical outcomes remained stable, with no implant failures or technical and biological complications throughout the observation period. Patient satisfaction was very high at baseline (crown delivery) and remained consistently high at 6 and 12 months of follow-up. Crown insertion 3 days after implant placement was rated as an easy procedure by clinicians. Two adjacent single implants with immediate definitive restorations(<72 h) in the posterior region appear to be a viable and easy treatment option to shorten the overall treatment time and potentially enhancing patient satisfaction. However, randomized controlled trials are needed to confirm the advantages of this treatment protocol over a delayed loading approach. In selected cases, immediate implant loading with definitive restorations in the posterior region appears a valuable and straightforward option to shorten the overall treatment time.

ObjectivesThe objective of this study is to analyze the clinical and radiographic outcomes of implant‐supported fixed protheses with cantilever extensions (ISFPCs) in the partially edentulous anterior mandible.Materials and MethodsPatients who received anterior mandible implant restoration between January 2016 and December 2021 were included. Patients with two, three, or four continuous missing teeth receiving adjacent implant supported single‐unit crowns (ISSCs), ISFPCs, implant‐supported fixed protheses without cantilever extensions (ISFPNs) were divided into groups: ISSC+ISSC, ISFPC, ISSC+ISFPC, three‐unit ISFPN, ISFPC+ISFPC, or four‐unit ISFPN, respectively. We recorded and evaluated survival rates, mechanical and biological complications, peri‐implant marginal bone loss (MBL), esthetic outcomes, and patient perceptions. Statistical analysis was performed using linear mixed models (LMM).ResultsThe study included 87 patients and 152 implants. No implant loss occurred during an average follow‐up of 3.48 ± 1.85 years (range: 1–7 years). According to LMM models, prosthetic type had a statistically significant impact on MBL during follow‐up periods, in favor of the ISFPC and ISFPC+ISFPC groups (0.16 ± 0.48 mm vs. 0.51 ± 0.49 mm, p = .034; 0.22 ± 0.49 mm vs. 0.60 ± 0.62 mm, p = .043, respectively). Mechanical and biological complications were relatively low and comparable. The four‐unit ISFPC group had higher subjective esthetic scores compared with the ISSC+ISSC group (98.6 vs. 83.8, p &lt; .05), and patients in the ISFPC+ISFPC group expressed greater satisfaction with cleanability than the ISFPN group (98.8 vs. 80.6).ConclusionISFPCs offer a highly predictable treatment option in the anterior mandible, characterized by high survival rates, and comparable complication rates, peri‐implant bone stability and esthetics to adjacent ISSCs or ISFPNs.

Clinical and radiographic evaluation of implant-supported single-unit crowns with cantilever extensions: A systematic review and meta-analysis.

When extended distally due to higher loading in the posterior region, implant-supported bar-retained overdentures with cantilever bar extension exhibit greater bending moments on the implants closest to the cantilever bar and increased stresses in the overdenture components. In this study, a new abutment-bar structure connection was introduced to minimize undesired bending moments and reduce the resulting stresses by increasing the rotational mobility of the bar structure on the abutments. Copings of the bar structure were modified to have 2 spherical surfaces, sharing the same center, located at the centroid of the top surface of the coping screw head. The new connection design was applied to a 4 implant-supported mandibular overdenture to create a modified overdenture. Both the classical and modified models had bar structures with cantilever extensions in the first and second molar areas and were analyzed for deformation and stress distribution using finite element analysis, which was also conducted for both the overdenture models without cantilever bar extensions. Real-scale prototypes of both models with cantilever extensions were manufactured, assembled on implants embedded in polyurethane blocks, and subjected to fatigue testing. Both models' implants were subjected to pullout testing. The new connection design increased the rotational mobility of the bar structure, minimized the bending moment effects, and reduced the stress levels in the peri-implant bone and overdenture components, whether cantilevered or not. Our results verify the effects of rotational mobility of the bar structure on the abutments and validate the importance of the abutment-bar connection geometry as a design parameter.

Mechanical Complication Rates and Optimal Horizontal Distance of the Most Distally Positioned Implant-Supported Single Crowns in the Posterior Region: A Study with a Mean Follow-Up of 3 Years.

PURPOSEThe aim of this study was to compare the efficacies of two-implant splinting (2-IS) and single-implant restoration (1-IR) in the first and second molar regions over a mean functional loading period (FLP) of 40 months, and to propose the appropriate clinical considerations for the splinting technique.MATERIALS AND METHODSThe following clinical factors were examined in the 1-IR and 2-IS groups based on the total hospital records of the patients: sex, mean age, implant location, FLP, bone grafting, clinical crown-implant ratio, crown height space, and horizontal distance. The mechanical complications [i.e., screw loosening (SL), screw fracture, crown fracture, and repeated SL] and biological complications [i.e., peri-implant mucositis (PM) and peri-implantitis (PI)] were also evaluated for each patient. In analysis of two groups, the chi-square test and Student's t-test were used to identify the relationship between clinical factors and complication rates. The optimal cutoff value for the FLP based on complications was evaluated using receiver operating characteristics analysis.RESULTSIn total, 234 patients with 408 implants that had been placed during 2005 - 2014 were investigated. The incident rates of SL (P<.001), PM (P=.002), and PI (P=.046) differed significantly between the 1-IR and 2-IS groups. The FLP was the only meaningful clinical factor for mechanical and biological complication rates in 2-IS.CONCLUSIONThe mechanical complication rates were lower for 2-IS than for 1-IR, while the biological complication rates were higher for 2-IS. FLP of 39.80 and 46.57 months were the reference follow-up periods for preventing biological and mechanical complications, respectively.

Mechanical complications after STEMI: Another collateral damage of the COVID-19 pandemic

Background: Extend fixed dental prostheses (FDPs) with cantilever extensions used over locations with insufficient bone to avoid bone grafting. Cantilever extensions in both full-arch and short-span bridges have been documented in recent comprehensive reviews. However, cantilever FDPs have been the topic of numerous complaints of technical and mechanical issues. Therefore, this article addressed numerous variables to be analyzed in terms of implantation success rate, prosthesis success rate, minor bone loss, mechanical and technical prosthesis problems, and biological complications. Other variables from in-vitro, in-silico, and in-vivo studies were searched for and described where they were present, in addition to the loading duration of the rehabilitations, resources for reconstruction, and implant system used. Objective of study: The present literature review aims to explore the use of cantilever-extending design as a successful treatment in implant-supported restorations for posterior regions. Results: A Google Scholar operator scanned the literature and ran a hand search of the leading implantology and prosthetics journals from 2003 to July the 11th, 2023. Only articles on cantilevers for posterior implant-supported fixed restorations were considered. The outcome factors were implant and prosthetics survival, mechanics, technical, and biology issues, and bone loss on the margins. To better understand the implant-supported restoration with the cantilever extension approach and to assess its viability and dependability in the field of dental implants, this review article will focus on studies conducted over the past 20 years, beginning in 2003 to 2023. Therefore, this literature review aims to examine how the cantilever extension idea has been used in the field of dental implantology. Conclusion: Thirty papers of cantilever extensions for implant-retained FPDs were chosen. The estimated in-vitro of 4 papers (14%), in-silico of 8 papers (27%), and in-vivo studies were of 17 papers (59%). There is a suggestion that cantilever extension can be an effective therapy in implant-supported restorations for posterior regions.

BackgroundThe transvenous implantable cardioverter‐defibrillator (ICD) lead is the most common source of complications in a traditional ICD system. This investigation aims to determine the incidence, predictors, and costs associated with these complications using a large insurance database.Methods and ResultsData from the OptumLabs™ Data Warehouse, which include diagnosis, physician and procedure codes, and claims from patient hospitalizations, were analyzed. Patients with a de novo ICD or cardiac resynchronization therapy defibrillator implanted from January 1, 2003, through June 30, 2015, were included; those who did not have continuous coverage beginning 1 year before implantation were excluded, resulting in 40 837 patients followed up over an average of 2.3±2.1 years. Patients were followed up until they had the procedure or their last active date in the database. Of 20 580 device procedures, 2165 (5.3%) and 771 (1.9%) had mechanical and infectious complications, respectively. The 5‐year rate of freedom from mechanical complication was 92.0% and 89.3% for ICDs and cardiac resynchronization therapy defibrillators, respectively. Infectious complications were more likely in patients with a history of atrial fibrillation, diabetes mellitus, and renal disease, and the risk increased with subsequent device procedures. Younger age, female sex, lack of comorbidities, and implantations between 2003 and 2008 were associated with more mechanical complications.ConclusionsIncidence of mechanical and infectious complications of transvenous ICD leads over long‐term follow‐up is much higher in the real world than in clinical studies. In our study cohort, 1 of 4 transvenous ICD leads had mechanical complications when followed up to 10 years. The high rate of reintervention leads to additional complications.

PURPOSE The modified lateral-screw-retained implant prosthesis (LSP) is designed to combine the advantages of screw- and cement-retained implant prostheses. This retrospective study evaluated the mechanical and biological complication rates of implant-supported single crowns (ISSCs) inserted with the modified LSP in the posterior region, and determined how these complication rates are affected by clinical factors.MATERIALS AND METHODSMechanical complications (i.e., lateral screw loosening [LSL], abutment screw loosening, lateral screw fracture, and ceramic fracture) and biological complications (i.e., peri-implant mucositis [PM] and peri-implantitis) were identified from the patients' treatment records, clinical photographs, periapical radiographs, panoramic radiographs, and clinical indices. The correlations between complication rates and the following clinical factors were determined: gender, age, position in the jaw, placement location, functional duration, clinical crown-to-implant length ratio, crown height space, and the use of a submerged or nonsubmerged placement procedure.RESULTSMechanical and biological complications were present in 25 of 73 ISSCs with the modified LSP. LSL (n=11) and PM (n=11) were the most common complications. The incidence of mechanical complications was significantly related to gender (P=.018). The other clinical factors were not significantly associated with mechanical and biological complication rates.CONCLUSIONWithin the limitations of this study, the incidence of mechanical and biological complications in the posterior region was similar for both modified LSP and conventional implant prosthetic systems. In addition, the modified LSP is amenable to maintenance care, which facilitates the prevention and treatment of mechanical and biological complications.

Background The data on all-ceramic implant reconstructions showed a high rate of veneering fractures. The monolithic design may reduce the technical complication rate. To date, the evidence on the CAD-CAM fabrication outcomes and the clinical performance is limited to glass-ceramic implant crowns. Recently, translucent zirconia was introduced exhibiting good mechanical properties and biocompatibility. Therefore, monolithic translucent zirconia implant crowns may be a valuable option in the posterior region Aim/Hypothesis The aim of the present clinical trial was to test whether or not translucent monolithic zirconia implant crowns fabricated by means of CAD-CAM technology render similar fabrication outcomes and perform similar to porcelain-fused-to-metal implant crowns in the posterior region. Material and Methods The present study was designed as a randomized controlled clinical trial. Eighty healthy patients in need of a single implant crown in the molar region were enrolled and a narrow-diameter implant (Straumann Roxolid, Tissue Level, Standard Plus, diameter of 3.3 mm) was placed. After tissue healing, implants were restored with screw-retained crowns. Following random allocation, either a monolithic zirconia crown bonded onto a titanium base (Straumann, Variobase) or a porcelain-fused-to-metal crown (control) was inserted. Modified USPHS criteria, crown and implant survival rates, change in marginal bone level (MBL), and clinical measurements (PD, PCR, BOP, KM) were assessed after crown insertion and at the 1-year follow-up visit. Data were analyzed descriptively. For continuous outcomes, student's unpaired t-test and the Mann-Whitney rank test were applied. For ordinal outcomes, the paired Wilcoxon test was applied. The level of statistical significance was set at P < 0.05. Results At baseline, eighty patients (36 females and 44 males) with 41 test crowns (mean age 56.8 y) and 39 control crowns (mean age 54.9 y) were evaluated. Anatomical contour and color match as compared to the neighboring dentition were rated ideal in 13 and 14 patients of the test group and in 20 and 37 patients of the control group, respectively. These differences between test and control group were statistically significant. Patient satisfaction was high in both groups after crown delivery and after one year. At the 1-year follow-up, one crown in each group was lost due to loss of the implant (test, loss of osseointegration; control, implant fracture). Minor chippings occurred in the control group only (3 40). Interproximal and occlusal contacts were lost in 4 and 11 patients of the test and control groups, respectively. There were no significant differences between the groups with respect to the change in MBL and to the clinical parameters. Conclusion and clinical implications Monolithic translucent zirconia crowns bonded to titanium base abutments are a valuable option to PFM crowns for single implants in the posterior area. The anatomical contour and the color match of the test crowns were inferior to the PFM crowns. Nevertheless, patient satisfaction was high. The outcomes may be attributed to the CAD-CAM devices used. The results of this study raise the question, whether titanium-zirconia narrow-diameter implants can be recommended to support molar crowns.

Implant-supported partial dentures with cantilever extensions (ISPDCs) present significant biomechanical challenges when rehabilitating partially edentulous patients, especially in the posterior region, where higher complication rates are often reported. This systematic review aimed to evaluate the complications, survival rates, and marginal bone loss associated with ISPDCs in posterior areas. The review protocol was registered with the PROSPERO database (CRD42024606201) and was conducted in accordance with PRISMA-P guidelines. A comprehensive search was performed across 10 databases for studies published up until 28 January 2025. Out of an initial 2142 records, 11 clinical studies met the inclusion criteria. The analysis showed a low failure rate for both prostheses and implants, at 1% (95% confidence interval: 0–3%) across the studies evaluated. However, noteworthy complications arose from biological factors as well as technical issues. Complications related to the prosthesis and abutment occurred in 14% of cases (95% CI: 5–26%), while loss of retention was noted in 13% of cases (95% CI: 7–21%). These technical issues were particularly more frequent in extensions greater than 7 mm. A significant difference was observed in marginal bone loss when comparing the final and initial measurements to the cantilever (p < 0.0001), which was influenced by the study design. Factors such as the type of occlusal veneering material, study design related to biological complications, the number of implants, marginal bone loss (between adjacent and distant sites), and the retention system did not significantly affect the complication rate (p > 0.05). The certainty of evidence for all primary outcomes was rated as low due to study limitations, heterogeneity, and risk of bias. In conclusion, ISPDCs show favorable survival outcomes when supported by adequate planning and clinical monitoring, although longer extensions require more cautious case selection and prosthetic design.

A long-term retrospective and clinical follow-up study of In-Ceram Alumina FPDs

Purpose: After the introduction of concept of osteointegration, dental implantology have been successful procedure in the dental field. Recently, it has shown successful results when used to restore single tooth missing. Considering the difference in bone quality of the mandible and maxilla, and the increased occlusal force in the posterior region, the success rates in each region may be different. In this study, success rates of single implants placed in the mandibular first and second molar areas were analyzed. Materials and methods: The subjects were patients (284 patients, 308 implants) who had been operated with single implant installation from 2002 to 2009 in seven dental clinics in Daegu city. One hundred sixty eight implants were placed in the mandibular 1st molar and 140 implants were placed in the mandibular 2nd molar. They were analyzed according to implant site, age, sex, length and diameter. Results: The survival rates of single implant of this study were 97.6% in the mandibular 1st molar and 92.9% in the mandibular 2nd molar. In the mandibular 1st molar, 4 implants were failed. In the mandibular, 2nd molar, 10 implants were failed. Conclusion: The restoration of the mandibular 1st molar using single implant was found to be clinically acceptable treatment and showed higher survival rate than mandibular 2nd molar single implant. Single implant in mandibu- lar 2nd molar needs careful consideration of poor bone quality, risk of overloading and anatomical structure of the mandible. (J Korean Acad Prosthodont 2013;51:252-60)

Today there are several treatment techniques available to replace a missing tooth. Since the beginning of the 1990s, it has become increasingly common to treat individual tooth loss with dental implants. Important patient factors are survival, success, functionality, aesthetics, oral health and quality of life. The range of indications and possibilities for implant treatment has broadened compared to the originally proposed treatment indications. A variety of methods, components and materials are available today. Improvements of the implant surface have led to shorter healing periods, which has affected the overall treatment time. Methods for computer-assisted implant planning and surgical guides have been developed to improve treatment planning. Several techniques are involved in the manufacturing of implant-supported single crowns, from the traditional plaster models, wax, casting and porcelain veneering to 3D scanning, computer aided design and manufacturing. It is important that all these treatment modalities are evaluated in a systematic and scientific way to ensure that the treatment given is the best one possible according to the individual conditions that exist. The general aim of this project was to evaluate the treatment outcome between different treatment modalities for single dental implants. Study I aims to retrospectively evaluate implant survival. Patient reported outcome measures, marginal bone loss (MBL), clinical and esthetic outcomes following conventional single implant treatment. The aim of study II, a prospective randomized clinical study, was to compare the overall treatment outcome following immediate loading (IL) and delayed loading (DL) of single implants. In study III the aim was to in a vitro setting evaluate the deviation in final dental implant position after the use of surgical guides fabricated from two different desktop 3D printers using a digital workflow. For study IV the aim was to, in a non-randomized study, compare clinical and aesthetic outcomes between immediately loaded single implants placed with and without a fully guided-surgery procedure (DIL). In study I a total of 85 implants were examined after a mean follow-up time of 7.51 years. The 5-year implant survival rate was98.4% (95% CI: 96.3% - 100%), with a crown survival rate of91.8% (95% CI: 86.3%-97.3%). Overall mean MBL was -0.13 mm. Final and initial total Pink esthetic score (PES) were 9.61 and 11.49 (P&lt;.001) Mean White esthetic score (WES) was 6.48 at final follow-up. Visual analog scale (VAS) score for soft tissue and implant-supported crown aesthetics were 73.5 and 82.1 (maximum score 100). A oral health impact profile-14 (OHIP-14) 14 score of 16.11 was observed at the final follow-up. Study II and IV found implant survival rates of 100%, 96% and 90.5 % for IL, DL and DIL, respectively, after 1-year. No statistically significant differences were found for MBL, PES, WES and OHIP-14after 1-year. Statistically significant lower papilla index scores were found for the IL. Overall statistically significant improvement inPES, WES and OHIP-14 were found over time. In the DIL group a moderate correlation between aesthetics and deviation in fixture position was found. For Study III a statistically significant difference between stereolithography and direct light processing (DLP) was found fordeviation at entry point (P = .023) and the vertical implant position(P = .009). Overall lower deviations were found for the guides from the DLP printer, with the exception of deviation in horizontal implant position.The results from these studies suggest that good clinical results can be achieved with different treatment modalities for single implants. Positive advantages with immediate loading and guided surgery is primarily seen in the early faces of the treatment procedure only. Care needs to be exerted with technically complicated treatment procedures as the effect on implant survival should not be underestimated. Further studies have to be performed to evaluate guided surgery and immediate loading to identify possible factors effecting survival.