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BACKGROUND: This study aimed to assess the effect of the "cut-out rescan" strategy on the accuracy of intraoral digital scans from 25° convergent implants positioned at two distinct depths. MATERIAL AND METHODS: Two customized models were fabricated, each designated to receive two posterior converged implant fixtures: one at a depth of 1 mm and the other at a depth of 4 mm. Initially, the models were scanned as reference casts using a lab scanner. The test group was involved in scanning the 1-mm and 4-mm implant models using an intraoral scanner in the following order: (1) scanning the 1-mm (T1; n = 10) and (2) 4-mm (T4; n = 10) implant groups with scan bodies connected to both fixtures in each model; (3) cut-out rescan (COR) in the 1-mm (COR1; n = 10) and (4) 4-mm (COR4; n = 10) models, leading to 40 digital files in standard tessellation language format. The mean absolute deviation (MAD), in terms of trueness and precision, between the experimental and control scans was assessed through the alignment of their respective datasets using three-dimensional analysis software. Two-way analysis of variance (ANOVA) and Levene's tests were used to analyze the data. RESULTS: The COR4 group exhibited the highest MAD, indicative of both trueness and precision (Mean ±SD: 55.659 ±34.802). In contrast, the T1 group demonstrated the lowest MAD (Mean ±SD: 43.225 ±19.237). However, the ANOVA analysis showed no significant influence of depth (P = 0.506) or type of scan (P = 0.442) on the MAD. Precision also did not differ significantly across groups (P = 0.071). CONCLUSIONS: The cut-out rescan approach demonstrated an accuracy comparable to that of the one-time scan method. CLINICAL SIGNIFICANCE: Digital intraoral scanning provides clinicians with a range of tools to navigate challenging conditions in which conventional methods may prove difficult, such as cases involving angled adjacent implants. In these scenarios, the cut-out rescan tool serves as a valuable resource, aiding clinicians in overcoming the challenges associated with impression-making owing to the convergence of placed implants.

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OBJECTIVES: To compare miniscrew versus bone tracing registration methods on dental implant placement accuracy and time efficiency in edentulous jaws using a dynamic computer-assisted implant surgery (d-CAIS) system. METHODS: Twelve fully edentulous maxillary models were allocated into two groups: miniscrew tracing (MST) group, where registration was performed by tracing four miniscrews; and bone tracing (BT) group, where registration was conducted by tracing maxillary bone fiducial landmarks. Six implants were placed on each model using the X-Guide® d-CAIS system. Pre- and postoperative cone-beam computed tomography (CBCT) scans were superimposed to evaluate implant placement accuracy. The time required for registration and the overall surgery time were also recorded. RESULTS: Thirty-six implants were placed in each group. The MST group showed significantly lower mean angulation deviations (mean difference (MD): -3.33°; 95 % confidence interval (CI): -6.56 to -0.09); p = 0.044), 3D platform deviations (MD: -1.01 mm; 95 % CI: -1.74 to -0.29; p = 0.006), 2D platform deviations (MD: -0.97 mm; 95 % CI: -1.71 to -0.23; p = 0.010), and 3D apex deviations (MD: -1.18 mm; 95 % CI: -1.92 to -0.44; p = 0.002) versus the BT group. The overall surgery time was similar for both groups (MD: 6.10 min.; 95 % CI: -0.31 to 12.51; p = 0.06), though bone tracing required significantly more time compared with miniscrew registration (MD: 4.79 min.; 95 % CI: 2.96 to 6.62; p < 0.05). CONCLUSIONS: Registration with MST increases the accuracy of implant placement with a d-CAIS system in edentulous jaws compared with the BT method, and slightly reduces the overall surgery time. CLINICAL SIGNIFICANCE: Miniscrew tracing registration improves implant placement accuracy in comparison with bone tracing registration.

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OBJECTIVES: One stage functional jaw reconstruction is defined as the resection and reconstruction of segmental defects in conjunction with the placement of dental implants in an ideal prosthetic position and loaded with a provisional restoration, during one surgical procedure. The aim of the study is to describe clinical outcomes of patients who underwent one stage functional jaw reconstruction. METHODS: Patients who underwent one-stage functional jaw reconstruction, from January 2013 to March 2016 were recalled in 2022 and 2023. Planning and execution for the reconstruction utilized either analogue or digital techniques. Outcome parameters recorded were treatment-related outcomes at patient level, implant-related outcomes and patient-reported outcome measures. RESULTS: Eighteen patients underwent one-stage jaw reconstruction with a total of 57 implants. Four patients had maxillary and 14 had mandibular reconstructions. Ten patients underwent postoperative radiotherapy. Ten patients were planned using analogue and eight by digital planning. Three patients had partial flap necrosis, three patients had plate fractures, implant loss was seen in one patient and four patients died during the period. A functional prosthesis was provided in 16 out of the 18 patients. CONCLUSION: One-stage functional jaw reconstruction is a predictable method for providing rehabilitation with successful outcomes at 7-11 years. However, caution should be exercised when the treatment modality is carried out in patients with malignant pathologies who have undergone radiotherapy.

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OBJECTIVES: To compare the accuracy and operative time of implant placement using a dynamic computer assisted implant surgery (dCAIS) system based on a cone beam computer tomography (CBCT) image, with and without superimposing a standard tessellation language (STL) file of an intraoral scan of the patient. METHODS: Ten identical resin models simulating an upper maxilla with posterior edentulism were assigned to two groups. In the CBCT+STL group, a CBCT file and an intraoral STL file were superimposed and used for registration; in the CBCT group, registration was performed using CBCT images. Six implants were placed in each model using the Navident® dynamic navigation system. Anatomy registration was performed by tracing fiducial points on the CBCT or STL image, depending on the group. Preoperative and postoperative CBCT images were overlaid to assess implant placement accuracy. RESULTS: Sixty implants were analyzed (30 implants in each group). 3D platform deviation was significantly lower (mean difference (MD): 0.17 mm; 95 % confidence interval (CI): 0.01 to 0.23; P = 0.039) in the CBCT+STL group (mean: 0.71 mm; standard deviation (SD): 0.29) than in the CBCT group (mean: 0.88 mm; SD: 0.39). The remaining accuracy outcome variables (angular deviation MD: -0.01; platform lateral deviation MD: 0.08 mm; apex global MD: 0.01 mm; apex depth MD: 0.33 mm) and surgery time (MD: 3.383 min.) were similar in both groups (p > 0.05). CONCLUSIONS: The introduction of an intraoral scan (STL) seems to reduce deviations slightly in dental implant placement with dCAIS systems. However, the clinical repercussion of this improvement is questionable. CLINICAL SIGNIFICANCE: Superimposing an intraoral scan on the CBCT image does not seem to increase the accuracy of dCAIS systems but can be useful when radiographic artifacts are present.

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OBJECTIVE: To compare the implant-abutment connection microgap between computer-aided design and computer-aided manufacturing (CAD/CAM) milled or laser-sintered cobalt-chrome custom abutments with or without ceramic veneering and titanium stock abutments with or without crown cementation. MATERIAL AND METHODS: Six groups of six abutments each were prepared: (1) CAD/CAM cobalt-chrome custom abutments: milled, milled with ceramic veneering, laser-sintered, and laser-sintered with ceramic veneering (four groups: MIL, MIL-C, SIN, and SIN-C, respectively) and (2) titanium stock abutments with or without zirconia crown cementation (two groups: STK and STK-Z, respectively). Abutments were screwed to the implants by applying 30 Ncm torque. All 36 samples were sectioned along their long axes. The implant-abutment connection microgap was measured using scanning electron microscopy on the right and left sides of the connection at the upper, middle, and lower levels. Data were analyzed using the Kruskal-Wallis test (p < .05). RESULTS: Mean values (µm) of the microgap were 0.54 ± 0.44 (STK), 0.55 ± 0.48 (STK-Z), 1.53 ± 1.30 (MIL), 2.30 ± 2.2 (MIL-C), 1.53 ± 1.37 (SIN), and 1.87 ± 1.8 (SIN-C). Although significant differences were observed between the STK and STK-Z groups and the other groups (p < .05), none were observed between the milled and laser-sintered groups before or after ceramic veneering. The largest microgap was observed at the upper level in all groups. CONCLUSIONS: Titanium stock abutments provided a closer fit than cobalt-chrome custom abutments. Neither crown cementation nor ceramic veneering resulted in significant changes in the implant-abutment connection microgap.

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Effective treatment planning is crucial for implant-supported dental prostheses' success, requiring a thorough assessment of various factors, including bone quality, quantity, and available space. Evaluating space availability, encompassing height, width, and angulation, is imperative to ensure optimal implant positioning devoid of anatomical limitations. Adequate vertical space is essential for accommodating the implant-supported restoration while preserving proper occlusal function and esthetics. However, not all cases adhere to ideal standards, especially those featuring limited interocclusal space, as seen in scenarios of long-standing edentulous areas lacking prior prosthetic rehabilitation. Ideally, the interocclusal space should measure between 8-12 mm vertically. This case report details the management of reduced interocclusal space through the strategic placement of deeply positioned implants and the incorporation of a screw-retained fixed partial denture, effectively addressing the challenges associated with limited space.

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BACKGROUND: Focal and florid cemento-osseous dysplasia are benign fibro-osseous lesions affecting the quality and quantity of the jawbones. This study aimed to determine the viability of implant-based approaches in the affected patients. MAIN TEXT: Different scientific databases, including PubMed/MEDLINE, Scopus, Web of Science, Embase, the Cochrane Library, and Google Scholar, were searched until October 8, 2023, using a pre-determined search strategy. Two reviewers screened the retrieved reports and extracted the required information from the included studies. The eligibility criteria included English-language case reports/series or clinical trials. The JBI critical appraisal checklist for case reports was used to assess the methodological quality of the included studies. Three studies were deemed eligible to be included in this study out of the initial 202 records found. Five implants were placed in three patients, positioned in the proximity of the lesion area, without any additional treatment to remove the pathology. The mandibular posterior area was the affected site in all patients. Only one implant failed in one patient after 16 years, which was attributed to peri-implantitis and not the lesion. Other implants demonstrated successful maintenance over follow-up periods. CONCLUSIONS: Although the number of the included records was relatively low to draw firm conclusions, it seems that implant-based treatments in patients with focal/florid cemento-osseous dysplasia could be viable, considering a conservative and well-planned approach.

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AIMS: In the literature, it is still unclear if the decisions for selecting the type of implant crown-retaining system are based on scientific-based research or if the Universities' choices, Implant marketing trends, or finances could have a major influence on the private dentists' decisions. OBJECTIVES: Therefore, this study aimed to evaluate the crown-retaining system (cement- or screw-retained) used in dental schools and private dental practices. METHODS: A 13-item questionnaire was sent to Canadian dental schools (n = 10) and dental offices in London (n = 298), Canada. The questionnaire included demographic questions and questions to reveal the dentists' perspectives on prosthetic implant treatment between the two-retaining systems. Results were analyzed using descriptive statistics and multinomial logistic regression (p = 0.05). RESULTS: Twenty-four private dentists and five dental schools responded to the survey - 62.5% of private practitioners and 60% of universities reported using both systems. A trend was observed in using screw-retained systems by dentists who graduated 5-10 years ago. Straumann, Astra, and Nobel Biocare were the private practices and dental schools' preferred implant systems. The use of platform switching for all cases was selected by 54.2% of the private practitioners and 40% of the dental schools. Resin cement was the private practice's preferred cementation method; the dental schools used glass ionomer and zinc phosphate cement. The multinomial logistic regressions showed no statistical difference between the crown-retaining system chosen and the decision factors. The laboratory technician's recommendations and cost influenced the decision-making process for private dentists. For the universities, perio-restorative outcome, implant position, survival rates, institute preferences, and evidence-based research influenced the crown-retaining system's decision-making process.  CONCLUSION: The Canadian dental schools and private practice reported using both screw- and cement-retaining systems. However, there was a difference in the selection criteria as the universities showed a tendency towards a more research-based approach in their decision, while for the private practices, the technicians' recommendations and cost played a major role in the decision process. It was noted that the implant systems preconized by the Universities were observed to be used in private practices.

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The concept of bilateral cantilevers on a single central implant (T-design) for three-unit implant-supported fixed dental prostheses (ISFDPs) has not been explored nor tested. This technical hypothesis aimed to explore the feasibility of such an approach as a cost-effective alternative to conventional treatments. Careful considerations regarding implant diameter, length, ideal position, occlusal scheme, and bone remodeling are essential to ensure adequate support, stability, and prevention of complications. In this proof of concept, we present a preliminary case with this novel design to replace missing posterior teeth in a patient with narrow bone conditions. In addition, a series of planned investigations and preliminary results, including preclinical studies, are presented to illustrate our concept and its potential clinical implications. Clinically, after two-year follow-up, healthy and stable peri-implant tissues around the ISFDP exemplarily demonstrated excellent stability, functionality, and comfort, which is supported by acceptable fracture resistance data in vitro, suggesting indeed the practical potential and suitability. Thus, we claim that such a treatment modality has the at least theoretical potential to revolutionize implant dentistry by providing innovative and cost-effective treatment options for patients with partial ISFDPs in very specific cases. Of course, further research and evaluations are necessary to validate the clinical implications of this innovative hypothesis. Implementing the 3-on-1 T-bridge approach in partial ISFDPs could offer a promising alternative to traditional methods. If proven successful, this technique may lead to significant advancements in clinical practice, providing a less invasive cost-effective treatment option.

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OBJECTIVES: This study aimed to compare the effect the radiographic marker registration (RMR) and markerless tracing registration (MTR) on implant placement accuracy using a dynamic computer-assisted implant surgery system (dCAIS). Additionally, this study aimed to assess the surgical time and whether the implant location influences the accuracy of the two registration methods. METHODS: 136 dental implants were randomly allocated to the RMR or MTR group and were placed with a dCAIS in resin models. Preoperative and postoperative Cone Beam Computer Tomograms (CBCT) were overlaid and implant placement accuracy was assessed. Descriptive and multivariate analysis of the data was performed. RESULTS: Significant differences (P < 0.001) were found for all accuracy variables except angular deviation (RMR:4.30° (SD:4.37°); MTR:3.89° (SD:3.32°)). The RMR had a mean 3D platform deviation of 1.53 mm (SD:0.98 mm) and mean apex 3D deviation of 1.63 mm (SD:1.05 mm) while the MTR had lower values (0.83 mm (SD:0.67 mm) and 1.07 mm (SD:0.86 mm), respectively). In the MTR group, implant placement in the anterior mandible was more accurate (p < 0.05). Additionally, MTR did not significantly increase the surgical time compared with RMR (P = 0.489). CONCLUSIONS: MTR seems to increase the accuracy of implant placement using dCAIS in comparison with the RMR method, without increasing the surgical time. The operated area seems to be relevant and might influence the implant deviations. CLINICAL SIGNIFICANCE: Considering the limitations of this in-vitro study, MTR seems to provide a higher accuracy in implant placement using dCAIS without increasing the surgical time. Furthermore, this method does not require radiographic markers and allows re-registration during surgery.

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The aim of this study was to evaluate the accuracy of the Implant Disease Risk Assessment (IDRA) tool in predicting the occurrence of peri-implantitis in patients who have received at least one implant, with a follow-up of up to 8 years. The records of patients who received one or more implants in the periodontology or oral surgery department of Saint Joseph University of Beirut between 2014 and 2018 were collected. Parameters related to the IDRA tool were obtained and the risk level calculated. Patients were recalled to assess their peri-implant status. The association between the IDRA risk level and the incidence of peri-implantitis was estimated. Overall, 145 patients were included in the study. A statistically significant association was found between the IDRA risk levels and the incidence of peri-implantitis (P = 0.003). High risk patients had 5.2 times higher odds of developing peri-implantitis than low-to-moderate risk patients (P < 0.001). Receiver operating characteristic curve analysis demonstrated a 69% probability that IDRA can identify patients at risk of developing peri-implantitis (P = 0.003). Further analysis found the percentage bleeding on probing to be the only significant IDRA vector. Within the limitations of this study, the IDRA tool is considered potentially useful for identifying patients at risk of developing peri-implantitis. It may serve as one component of a comprehensive peri-implant assessment, pending further enhancement of its predictive precision. Moreover, this tool can be considered before implant placement and during the periodontal maintenance phase. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04888572.

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BACKGROUND: Complete tooth loss is a significant global oral health issue, particularly impacting older individuals with lower socioeconomic status. Computer-assisted technologies enhance oral healthcare access by the elderly. Despite promising in vitro reports on digital denture materials, evidence from randomized clinical trials (RCTs) is lacking to verify their performance. This cross-over RCT will investigate whether 3D-printed implant-retained mandibular overdentures (IMO) are more satisfactory for edentulous seniors than those made through traditional methods. METHODS/DESIGN: We will recruit 26 completely edentulous participants (any sex/gender) based on the following eligibility criteria: age ≥ 60 years, no tooth extraction in the past 12 months, two implants in the lower jaw, and need for new dentures in both jaws. Each participant will receive two denture pairs, either manufactured by 3D printing or traditionally, to be worn in a random order. A timeline of 3 months with each denture pair will be considered for outcome assessment (total: 6 months). Patient satisfaction with dentures will be measured by the McGill Denture Satisfaction Questionnaire. We will evaluate other patient-reported outcomes (including oral health-related quality of life) as well as clinician-assessed quality and cost. At the end of the trial, participants will choose which denture pair they wish to keep and interviewed about their experiences with the 3D-printed IMO. The quantitative and qualitative data will be incorporated through an explanatory mixed-methods strategy. A final quantitative assessment will happen after 12 months with the preferred IMO to assess the long-term performance and maintenance needs. DISCUSSION: This mixed-methods RCT will explore patient experiences with 3D-printed IMOs, aiming to assess the potential for altering clinical practice and dental public health policies. Our results will inform policies by showing whether 3D printing offers comparable outcomes at lower costs, facilitating greater access to oral care for the elderly. TRIAL REGISTRATION: ClinicalTrials.gov, NCT06155630, Registered on 04 December 2023. https://classic. CLINICALTRIALS: gov/ct2/show/NCT06155630.

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PURPOSE: The objective of this retrospective study was to evaluate the effect of the interproximal contour of single external hexagon implant restorations on the prevalence of peri-implantitis. MATERIAL AND METHODS: Records of 96 patients and 148 external hexagon (EH) implants with time in function ranging from 1 to 17 years were included in the study. The most recent clinical and radiographic data were collected from records and the prevalence of peri-implantitis was defined according to the 2017 World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions. Marginal bone level (MBL), emergence angle (EA), emergence profile (EP), and crown/implant platform horizontal ratio (CIHR) were obtained from periapical radiographs. Dichotomous variables at the patient- and implant level were compared with association tests. Mann-Whitney U-Test was performed to compare continuous quantitative values between the studied groups. Binomial logistic regression was conducted to identify risk indicators associated with the peri-implantitis event at the patient- and implant level, with the significance level set at 5% for all tests. RESULTS: Nineteen patients (19.2%) and 24 implants (16.2%) with a mean time in function of 5.0 ± 4.7 years were classified as having peri-implantitis. No statistically significant differences concerning gender, mean age, implant location in the jaw, or time in function were observed between patients with or without peri-implantitis (p > 0.05). Of 24 implants with peri-implantitis 10 (41.7%) displayed EA ≤ 30° (16.4%) while 14 (58.3%) presented EA > 30° with no statistical difference between the groups (p > 0.05). No statistically significant associations were identified between EA, EP, or CIHR and the prevalence of peri-implantitis. CONCLUSION: The findings seem to indicate that the EA, EP, and CIHR of single restorations over external hexagon implants are not associated with the presence of peri-implantitis. However, prospective studies with larger samples are required to better ascertain such an association in the long term.

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PURPOSE: To assess the complications, satisfaction, and quality of life of patients rehabilitated with delayed and immediate loading of single crowns. MATERIALS AND METHODS: An electronic search was conducted in PubMed/MEDLINE, Scopus, Web of Science, Cochrane Library, and Embase databases up to February 2023. Only prospective studies and randomized and nonrandomized clinical trials comparing immediate and delayed loading were included. For the quantitative analysis, dichotomous and consistent variables were evaluated with a 95% confidence interval. RESULTS: A total of 20 studies were evaluated. No statistically significant difference was observed between protocols: satisfaction (I2: 0%; P = .42), quality of life (I2: 0 %; P = .05), biologic complications (I2: 9%; P = .17), mechanical complications (I2: 58%; P = .84), and survival rate (I2: 0%; P = .38). The subgroup analysis showed significant differences only for marginal bone loss (MBL) when immediate implants were placed in the mandible (I2: 15%; P = .01) and posterior zone (I2: 0%; P = .001). CONCLUSIONS: Complications and patient-centered outcomes for immediate single-implant crowns were comparable to delayed loading. Scientific evidence showed no significant difference between loading protocols for survival rates. Note that several factors could interfere with the complication events, implant failures, and MBL. The subgroup analysis showed that only immediate implants placed in the posterior mandible had a higher and statistically significant mean MBL.

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PURPOSE: This study aimed to develop and evaluate a simple, non-destructive method for assessing the misfit and passivity of implant-retained prostheses frameworks. MATERIALS AND METHODS: To simulate the rehabilitation of a mandible posterior partially edentulous area using 3-unit screw-retained frameworks supported by two implants were fabricated and divided into the following five groups (n = 10 in each group): OP = one-piece framework cast in Co-Cr with the conventional method (control-group); Co-Cr frameworks sectioned and welded by laser (=LAS) or tungsten inert gas (=TIG); Co-Cr CAD-CAM = milled Co-Cr framework; Zir CAD-CAM = milled zirconia framework. The horizontal |X| and vertical |Y| misfits were measured using confocal laser scanning microscopy with one or both screws tightened. Data were analyzed by a two-way ANOVA with repeated measures and Bonferroni correction (α = 0.05). RESULTS: The greatest |X| misfit was observed in the OP group with both screws tightened (290 µm) and one screw tightened (388 and 340 µm). The conventional casting groups sectioned and welded by laser or TIG had lower mean values (235.35 µm, both screws tightened; and 275 µm, one screw tightened) than the OP framework. However, these values still exceeded those of the milled Co-Cr and zirconia frameworks (190 and 216 µm with both screws tightened). Across all reading conditions, every framework subjected to testing consistently maintained vertical |Y| misfit levels below the threshold of 53 µm; however, the milled frameworks exhibited higher vertical misfits than the frameworks obtained by the conventional cast method. CONCLUSIONS: The frameworks, whether cast and sectioned with laser welding or milled from Co-Cr, exhibit improved marginal misfit and enhanced passive fit when compared to other fabrication methods. Additionally, the use of confocal laser scanning microscopy is highly effective for passivity and misfit analysis.

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Resin coating in implants rehabilitation cannot always be aesthetic, durable and comfortable for the patient mainly due to the limited dimensions of the final structure. Intraoral welding technique and computer-aided designed prosthetic shells may be a solution. This in vitro study evaluates the capacity of load and the weakest point of implant-supported provisional prosthesis using welded titanium framework. Twelve samples were produced to simulate an implant supported fixed prosthetic bridge. Two implants (Ankylos; Dentsply Sirona Implants; Germany) were inserted inside blocks of nanoceramic material produced with a stereolithographic 3D printer. A polymethylmethacrylate (PMMA) resin shell was performed with CAD/CAM and relined on welded framework. Six samples were produced with the same procedure reducing resin thickness. The samples were subjected to fatigue test (6,500,000 cycles) using ElectroForce 3310 fatigue machine (t1); subsequently a mechanical compression test using a universal Shimadzu AGS-X 10 machine (t2). The samples were analyzed with a photographic and radiographic documentation at t0, t1 and t2. The samples survived mechanical fatigue test without evidence of failure. The radiographic and photographic evaluation revealed the fracture of resin coating after the mechanical compression test. The samples with minimal resin thickness fractured first. Adequate assessment of the resin thickness is mandatory to improve the longevity of these rehabilitations. CAD-CAM digital prosthetic design allows us to optimize the thicknesses and the prosthetic shapes, allowing us to obtain good degrees of resistance even in the presence of reduced prosthetic spaces.

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OBJECTIVES: To assess the mechanical durability of monolithic zirconia implant-supported fixed dental prostheses (iFDP) design on one implant, with a distal and a mesial extension cantilever bonded to a titanium base compared to established designs on two implants. MATERIALS AND METHODS: Roxolid Tissue level (TL), and tissue level x (TLX) implants were used to manufacture screw-retained 3-unit iFDPs (n = 60, n = 10 per group), with following configurations (X: Cantilever; I: Implant, T: Test group, C: Control group): T1: X-I-X (TL); T2: X-I-X (TLX); T3: I-I-X (TL); T4: I-I-X (TLX); C1: I-X-I (TL); C2: I-X-I (TLX). The iFDPs were thermomechanically aged and subsequently loaded until fracture using a universal testing machine. The failure load at first crack (Finitial) and at catastrophic fracture (Fmax) were measured and statistical evaluation was performed using two-way ANOVA and Tukey's post-hoc tests. RESULTS: The mean values ranged between 190 ± 73 and 510 ± 459 N for Finitial groups, and between 468 ± 76 and 1579 ± 249 N for Fmax, respectively. Regarding Finitial, neither the implant type, nor the iFDP configuration significantly influenced measured failure loads (all p > 0.05). The choice of implant type did not show any significant effect (p > 0.05), while reconstruction design significantly affected Fmax data (I-I-Xa < X-I-Xb < I-X-Ic) (p < 0.05). The mesial and distal extension groups (X-I-X) showed fractures only at the cantilever extension site, while the distal extension group (I-I-X) showed one abutment and one connector fracture at the implant/reconstruction interface. CONCLUSION: Results suggest that iFDPs with I-X-I design can be recommended regardless of tested implant type followed by the mesial and distal extension design on one implant abutment (X-I-X).

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OBJECTIVE: Evaluate the long-term outcomes of full-arch rehabilitation using immediate dental implant placement and continuous functional loading with full-fixed dental prostheses (FFDPs). MATERIALS AND METHODS: Fifty-six patients received temporary implants (n = 327) at maxillary augmentation with calvarial bone. A provisional acrylic FFDP was immediately loaded onto these implants. After 6 months, the temporary implants were replaced with definitive implants (n = 326) and immediately loaded with a second provisional FFDP (N = 55). Subsequently, a baseline radiograph was taken following a 6-month healing period. The second bridge was then substituted with a definitive FFDP. Primary outcomes included peri-implant marginal bone level (MBL) and definitive implant survival. Secondary outcomes evaluated provisional implant and prostheses survival, complications, and patient satisfaction. RESULTS: The provisional implants had a survival rate of 97.9%. One patient was excluded from further analysis due to loss of temporary implants and first FFDP. The definitive implant survival rate after 10 years was 92.2%, with a moderate but significant decrease in MBL between baseline radiography and 10 years later (-0.08 ± 0.18 vs. -0.24 ± 0.44). However, large individual variations were observed, with 65.8% of implants showing no bone loss and 9.2% showing loss ≥0.5 mm. Sinusitis was experienced by 14.3% of patients upon surgery. Patient satisfaction was high or reported no issues after protocol completion (80%). One patient lost all six definitive implants and definitive FFDP 8.2 years after implant placement. CONCLUSIONS: The described protocol can be regarded as a long-term, highly successful method for full-arch rehabilitation of atrophied maxillae while enabling continuous masticatory and speaking functionality.

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BACKGROUND: Currently, oblique placement of long implants or the use of short implants to circumvent the maxillary sinus area and provide support for fixed prostheses are viable alternatives. The purpose of this study was to compare these two treatment concepts and ascertain which one exhibits superior biomechanical characteristics. METHODS: Two different treatment concept models were constructed. The first one, LT4I, consisting of two mesial vertical implants positioned in lateral incisor regions and two distal tilted implants (45°) situated in second premolar regions of the maxilla. The second model, VS4I, includes two mesial vertical implants in lateral incisor regions and two vertically positioned short implants in second premolar regions. Numerical simulations were conducted under three loading types: firstly, oblique forces upon the molars; secondly, vertical forces upon the molars; thirdly, oblique forces upon the incisors. The maximum principal stress (σmax) and minimum principal stress (σmin) of the bone, as well as von Mises stress of the implants, were calcuated. RESULTS: Under oblique loading on the molar, higher stress values in the bone were observed in LT4I group. Under vertical loading on molar, higher stress values in the bone were also observed in LT4I group. Furthermore, little difference was found between the two groups under oblique loading on the incisor. CONCLUSION: Both treatment concepts can be applicable for edentulous individuals with moderate atrophic maxilla. Compared to tilted implants, short implants can transmit less occlusal force to the supporting tissues.

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Incomplete orthodontic therapy can lead to severe root resorption, resulting in mobile and non-restorable teeth. This clinical report presents the diagnosis, treatment planning and oral rehabilitation of a young woman with failing dentition in the anterior maxilla due to orthodontically induced root resorption. The patient's chief complaint was mobile maxillary anterior teeth 2 years after discontinuing orthodontic treatment. Radiographic and clinical evaluations revealed a missing right first premolar and left premolars and grade III mobility from the right canine to the left lateral incisor. Due to a hopeless prognosis, extraction of the maxillary anterior teeth was planned, followed by grafting procedures. Four implants were immediately placed in the fresh sockets of the canine and central sites, and a removable provisional appliance was delivered to contour the soft tissues involved. The final restorations consisted of two three-unit layered zirconia implant-supported fixed dental prostheses. Well-planned immediate implant therapy and zirconia restorations can successfully replace mobile teeth with severe root resorption caused by external surface resorption from incomplete orthodontic treatment. Combining grafting procedures during implant placement can replace hard tissue lost due to extractions, whereas provisional restorations can re-establish optimal tissue architecture in the aesthetic zone. The present case offers insight into effective strategies for treating non-compliant or uncooperative patients with failing dentition due to orthodontically induced root resorption.

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