A systematic review of the survival and complication rates of implant-supported fixed dental prostheses (FDPs) after a mean observation period of at least 5 years

Digital Workflow and Guided Surgery in Implant Therapy-Literature Review and Practical Tips to Optimize Precision

The application of digital technology in implant dentistry refines prosthetically-driven treatment planning by integrating virtual facial and intraoral models with cone-beam computed tomography (CBCT) images. This integration enables the development of more personalized treatment plans, ensures precise implant positioning, and strengthens communication between clinicians and patients, thereby reducing potential errors and risks. Computer-aided implant surgery consists of two primary approaches: static-guided surgery, which uses a physical surgical stent to guide the osteotomy based on the preoperatively planned virtual implant position, and dynamic-guided surgery, which employs an optical tracking system with a real-time monitor display for the visualization of implant osteotomy inside the alveolar bone. Each approach offers distinct advantages and poses unique clinical challenges. This paper provides an overview of the current applications and literature on digital treatment planning and computer-aided implant surgery, discussing the advantages and limitations of each approach. Clinical cases are presented to illustrate the digital workflow and highlight key considerations for implementing these methods. Currently, the use of digital workflow in implant dentistry is rising, and it is essential to strike a balance between precision and practicality. The future is promising, with generalized adoption anticipated.

Clinical effectiveness of Zirconia versus titanium dental implants in anterior region: an overview of systematic reviews

BACKGROUND

Nowadays dental implants are commonly used and to fulfil esthetic demands, zirconia has been suggested as an implant material as an alternative to titanium. Many researchers and systematic reviews are documented on it, but the results have been often inconsistent. This overview of systematic reviews aimed to report on the factors that influence the clinical effectiveness of zirconia (Zi) versus titanium (Ti) dental implants in anterior region.

METHODS

This overview of systematic reviews (Registration Number CRD42023396206) is in accordance with the Transparent Reporting of Systematic Reviews and Meta-analyses. PubMed, Cochrane, Scopus, Embase and Google Scholar databases were sourced for systematic review and meta-analyses. Joanna Briggs Institute (JBI) criteria and Measurement Tool to Assess systematic Reviews" (AMSTAR-2), evaluated the quality. The PICO-focused question of this overview of systematic reviews was "What are the various factors influencing the clinical performance of Zi versus Ti implants in the anterior area?", Evaluations were assessed by two assessors. In case there was any uncertainty or dispute among the reviewers, the work was included for further screening. Using Cohen's kappa, the inter-reviewer reliability was evaluated.

RESULTS

Six reviews were chosen from 57 suitable reviews for this data analysis. Although the survival and effectiveness rates backed titanium implants, there was no conclusive proof of marginal bone loss. Zirconium implants performed better in terms of aesthetics.

CONCLUSION

Clinical performance of zirconia could be considered at par with titanium implants in the anterior area. Titanium has exhibited greater mechanical performance but no significant difference between two recorded. In future, studies with improved design are needed to identify biological and technical factors that affect implant's efficacy.

NOVELTY AND RELEVANCE

This is the first overview of systematic reviews focusing specifically on the anterior region, evaluates both aesthetic and biomechanical performance of Zi and Ti Implants, offers detailed insight into material-specific advantages and limitations. In the present clinical scenario it addresses a critical gap by comparing the performance of Zi and Ti implants and evaluates patient-centred priorities, particularly in the highly visible anterior region.

Comparison of three implant systems under preload loss: A finite element analysis validated by digital image correlation methods

PURPOSE

This study evaluated the effects of screw preload loss on three implant systems, both in silico and in vitro.

METHODS

Three finite element analysis (FEA) models of implant restorations were created using bone-level (BL, 4.8×12 mm; BLX, 4.5×12 mm) and tissue-level (TL, 4.8×12 mm) implant systems. The screws in each group were subjected to preloads of 100 N and 200 N, with an additional 130 N load applied to the crown tops. An in vitro study of the principal strain was conducted using digital image correlation (DIC) under the same conditions as for the FEA models. The results were evaluated for von Mises stress, principal strain, and sensitivity index.

RESULTS

During loading, the highest stress levels were observed in the implants and screws. In the BL group, the screws experienced the highest von Mises stress at 466.04 MPa and 795.26 MPa in the 100 N and 200 N groups, respectively. The BLX group showed the highest von Mises stress at 439.33 MPa and 780.88 MPa in the implants in the 100 N and 200 N groups. Sensitivity analysis revealed that the screws and abutments in the TL group were significantly more affected by the preload changes.

CONCLUSIONS

The abutment in the TL group was particularly sensitive to preload changes compared with those in the BL and BLX groups. Variations in the preload significantly affect the stress distribution in implants and screws. Maintaining screw preload stability under loading is crucial in clinical practice to prevent mechanical failure.

Evaluation of impact of intraoral scanning technology and scan body design on the accuracy of maxillary complete arch digital scans: A clinical study

STATEMENT OF PROBLEM

Intraoral scanners (IOSs) can be used to digitize complete arches with multiple dental implants; however, the influence of intraoral scanning technology and scan body system selection on accuracy in maxillary complete arches remains unclear.

PURPOSE

The purpose of this clinical study was to evaluate the accuracy in the maxillary arch, encompassing both trueness and precision, of 2 distinct intraoral scanning systems and 2 diverse scan body systems in comparison with the conventional reference method.

MATERIAL AND METHODS

Two participants were recruited with 6 maxillary bone-level implants (JDEvolution Plus; JDentalCare) placed in positions corresponding to the right first molar, right canine, right central incisor, left central incisor, left canine, and left first molar. All implants had multiunit abutments (Conical Abutment Straight; JDentalCare) screwed to the implants. Definitive casts from 2 edentulous maxillary impressions were made using a conventional method. The casts were digitized to create reference models using a laboratory scanner (E3; 3Shape A/S). Two experimental groups were created based on the IOS used: the TRIOS 3 group (TR3) and the Primescan group (PS). Two subgroups were generated depending on the scan body system used to digitize the spatial position of the implants: IPD scan body (IPD) and DAS scan body (DAS). The digital implant scan discrepancies between the control group and experimental scans were calculated. The normality of the data was assessed using the Shapiro-Wilk test (α=.05). Two-way ANOVA and post hoc pairwise comparison tests were used to compare the trueness, precision, and interaction between the intraoral scanner and the scan body (α=.05) RESULTS: Statistically significant differences (P<.001) were found between the intraoral scanners tested. No significant differences were found between the IPD and DAS scan body systems (P=.649), and none were found for the interaction between the IOS and the scan body (P=.524). Significant differences were observed between the following groups: PS-IPD and TR3-IPD, PS-IPD and TR3-DAS, PS-DAS and TR3-IPD, and PS-DAS and TR3-DAS (all P<.001).

CONCLUSIONS

The combination of intraoral scanner and scan body system is crucial to improve the accuracy of digital complete arch intraoral implant scans. In the maxillary arch, the Primescan IOS obtained the highest accuracy when compared with the TRIOS 3 IOS, independently of the scan body system used.

The Effect of Repeated Closing Torque on Torque Loss and Angular Deviation: An In Vitro Study

Loosening and fracturing of the central screw are common mechanical complications after implant restoration. However, the relationship between these complications and the repetitive tightening and loosening of the central screw during the fabrication and maintenance of the implant-supported restorations remains unknown. The purpose of this study was to evaluate the torque loss after repetitive tightening and loosening of the central screws on implants with different diameters as well as the changes in the angle deviation of the central screw relative to the implant. Twenty implants were divided into 2 groups based on diameter: 3.7 mm (group A) and 4.5 mm (group B) with 10 implants in each group. Each group was subdivided into 4 subgroups: A1, A2, B1, and B2 (n = 5). A closing torque of 15 N.cm was applied to groups A1 and B1, whereas a closing torque of 35 N.cm was applied to groups A2 and B2. Reverse torque measurements were taken 10 times for each group. The angular deviation of the central screw relative to the implant was recorded, and the surface wear of the central screw was observed under a scanning electron microscope. The data were analyzed using repeated measures 2-way analysis of variance (α = 0.05). Torque loss showed a significant upward trend across all groups with increased tightening cycle (P < .05). Implant diameter significantly influenced torque loss with smaller diameters exhibiting greater torque loss (P < .05). In addition, the angular deviation of the central screw relative to the implant was not affected by different diameters (P > .05). Still, it was affected by the closing torque and the cycles of multiple tightening and loosening procedures (P < .05). Under a 35 N.cm closing torque, initial torque loss ranged from 9.12 N.cm to 10.98 N.cm. Peak torque loss occurred at the 10th cycle with 16.40 N.cm values for 3.7-mm implants and 12.42 N.cm for 4.5-mm implants. Repeated tightening and loosening procedures increased both torque loss and angular deviation. The diameter of the implant may impact the torque loss with a larger diameter showing less torque loss. To reduce the risk of potential complications, it is suggested that the number of tightening cycles for narrow-diameter implants be limited.

The influence of the superimposition procedure and type of intraoral impression on the superimposition accuracy of CBCT scans with dental impressions in implant planning: an in-vitro study

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.

Angled Screw Channel-Retained vs. Cement-Retained Implant Crowns in Nonmolar Sites: A Systematic Review and Meta-Analysis

OBJECTIVES

To evaluate the clinical, radiographic, and aesthetic outcomes of angled screw channel (ASC) retained implant crowns to cement-retained implant crowns in nonmolar sites.

METHODS

Randomized and nonrandomized trials comparing ASC-retained and cement-retained implant crowns in single nonmolar locations were found by searching electronic databases (COCHRANE, EMBASE, and MEDLINE) up to January 2025. Changes in marginal bone level were the primary outcomes, whereas periodontal parameters, aesthetic outcomes, and technical complications were the secondary outcomes. Random-effects meta-analysis was used to calculate pooled effect sizes.

RESULTS

A total of 973 studies were identified, of which four studies with 167 single nonmolar implant crowns were included. Overall meta-analysis showed that the difference in marginal bone level was in favor of the ASC group, but the difference was not statistically significant (MD -0.03; 95% CI -0.12 to 0.06; p = 0.57). The ASC group had more positive changes in pink aesthetic score than the cemented group; however, the difference between the two groups was not statistically significant (MD -0.18; 95% CI -0.88 to 0.51; p = 0.61).

CONCLUSIONS

ASC-retained implant crowns in nonmolar sites have comparable short-term clinical, radiographic, and aesthetic outcomes to cement-retained implant crowns, with less bleeding on probing expected with ASC-retained crowns.

CLINICAL SIGNIFICANCE

The superiority of ASC-retained implant crowns over cement-retained implant crowns in nonmolars was not proven. There were no significant differences between ASC-retained and cement-retained implant crowns in terms of mean changes in marginal bone levels, probing pocket depths, aesthetic outcomes, technical complications, and implant failure.

In Vitro Reliability and Stress Distribution of Wide Diameter Extra-Short Implants as Support for Single Crowns and Fixed Partial Dentures

This study evaluated the reliability, failure mode, and stress distribution of wide-diameter extra-short dental implants (ESDI) as support for single crowns (SC) and fixed partial dentures (FPD) (3:1 crown-to-implant ratio [C:I]) for rehabilitation in the posterior atrophic mandible. For that, 126 ESDI (of 5 mm length) were allocated in four groups based on diameter (Ø4 and Ø6 mm) and prostheses (SC and FPD): SC4, SC6, FPD4, and FPD6. The fatigue test was performed by step-stress accelerated life testing (n = 21/group), failure mode by fractographic analysis, and stress distribution by finite element analysis: von Mises stress (σvM), maximum shear stress (τmax), and minimum principal stress (σmin). Reliability at 200 N was higher than 84% in both SC4 and SC6, with SC6 showing significantly higher reliability at 300 N. Failure mode involved the abutment (SC4 and SC6). The missions were suspended for the FPD groups due to 100% survival at the maximum load. The σvM showed a stress reduction of about 40% at the SC6 implant when compared to SC4 and FPD6 compared to FPD4. For the abutment, a minor decrease of at least 6.72% was observed comparing SC6 to SC4 and 2.78% for the FPD6 compared to FPD4. The τmax and σmin in the cortical bone demonstrated a stress reduction of at least 38.85% for the SC6 compared to SC4 and at least 3.78% in FPD6 compared to FPD4. The σmin in the cancellous bone showed an overall reduction of at least 8.46% for SC6 compared to SC4 and for FPD6 compared to FPD4. But, for τmax, in the cancellous bone, a 19.42% higher stress was found in SC6 compared to SC4 and 27.21% in FPD6 compared to FPD4. Finally, when splinting was used, a general stress reduction was found, about 50% in both diameters in the implant and abutment. According to the limitations of this in vitro study, it is possible to conclude that both groups (SC4 and SC6) showed high reliability in clinically relevant loads for the posterior atrophic mandible, SC6 having the lowest probability of failure at 300 N, with failure restricted to the abutment. Meanwhile, FPD6 has better stress distribution.

The Decision Between Tooth Retention or Replacement with Implants: A Continuing Dilemma

The global adoption of dental implants has significantly reshaped modern dental practices, with the market projected to reach USD 16 billion by 2029. However, despite high success rates, dental implants can still be prone to complications, particularly when underlying causes of tooth loss, such as periodontal disease and bone loss, are not addressed. This paper explores the biological and mechanical considerations in the decision-making process between preserving a tooth through periodontal therapy or opting for extraction and implant placement. It also highlights the importance of a holistic approach that includes assessing the patient's oral health, periodontal status, and the biomechanical factors influencing tooth retention. Periodontal therapy has been proven to be highly effective, with both non-surgical and surgical therapies showing long-term efficacy in preserving natural teeth, especially in the presence of furcation involvement. Studies show that proper periodontal management, including regular maintenance therapy after the active therapy, significantly enhances tooth survival, even in cases of severe periodontitis. In contrast, dental implants, while effective, are not free of complications, mainly inflammatory peri-implant diseases, but also mechanical complications, which can compromise long-term outcomes. The paper reviews clinical studies on implant survival, demonstrating that periodontal therapy can sometimes offer a more cost-effective and biologically sound alternative to implant therapy, especially for teeth with severe attachment loss or furcation involvement. In conclusion, treatment decisions should be based on a comprehensive evaluation of clinical, biological, and patient-specific factors. By integrating regenerative therapies even in more compromised teeth and addressing the root causes of tooth loss, implant rehabilitation can be postponed for many years and offer a cost-effective and successful long-term treatment plan. This approach underscores the importance of individualized care in the evolving landscape of restorative dentistry and implantology.

Load-bearing capacity of screw-retained fixed dental prostheses made of monolithic zirconia on different abutment designs and abutment-free implant connection

OBJECTIVES

A new abutment-free implant connection allows for direct screwing of FDPs on implants to avoid complications caused by cement rests or screw loosening, which may affect to screw torque and load distribution. The objective of this study was to test the initial (Fi) and final failure (Ff) loads and torque changes of abutment-free monolithic zirconia CAD-CAM fixed dental prostheses (FDPs) compared to titanium FDPs on different abutment designs.

METHODS

Three-unit screw-retained FDPs (n = 50) on two implants (n = 100) were divided into groups (n = 10) based on the implant-abutment connection and material of the supra-structure: (1) abutment-free monolithic CAD-CAM zirconia FDP (Abut-free-Zr), (2) abutment-free veneered titanium FDPs (Abut-free-Ti), (3) monolithic zirconia FDPs with titanium base abutments (Zr-Ti-Base), (4) monolithic zirconia FDPs on multi-unit abutments (Zr-MU), (5) veneered titanium FDP on multi-unit abutments (Ti-MU). All specimens were subjected to thermo-mechanical aging (1'200'000 Cycles, 49 N, 1.67 Hz, 5º to 50º C, dwelling time 120 s). Torque of the screws was measured, and static loading was performed. Data were tested using ANOVA and Tukey's tests (p < 0.05).

RESULTS

After thermo-mechanical aging, all screws showed reduced torque, Ti-MU significantly more reduction compared to Abut-Free-Ti (p = 0.0021). Titanium groups showed significantly lower Fi (N) values (171.4-230 vs 1272-1358,) due to veneering porcelain fractures (p = 0.0001) and significantly higher Ff (N) (2922 -3029 N vs. 1272-1358) values than zirconia groups (p < 0.0001).

CONCLUSIONS

Three-unit abutment-free monolithic zirconia FPDs showed similar failure loads compared to other zirconia groups, while the titanium groups exhibited superior final failure loads. Different abutment designs did not seem to affect the failure loads.

CLINICAL SIGNIFICANCE

The specific design of the novel implant interface allows for the fabrication of implant supported FDPs with personalized design directly on implant level without abutments. The monolithic zirconia FDPs on abutment-free implant connection can be used with good confidence since they exhibit similar mechanical stability as monolithic zirconia FDPs on titanium-base or multi-unit abutments.

Artificial intelligence for dental implant classification and peri-implant pathology identification in 2D radiographs: A systematic review

OBJECTIVE

This systematic review aimed to summarize and evaluate the available information regarding the performance of artificial intelligence on dental implant classification and peri-implant pathology identification in 2D radiographs.

DATA SOURCES

Electronic databases (Medline, Embase, and Cochrane) were searched up to September 2024 for relevant observational studies and both randomized and controlled clinical trials. The search was limited to studies published in English from the last 7 years. Two reviewers independently conducted both study selection and data extraction. Risk of bias assessment was also performed individually by both operators using the Quality Assessment Diagnostic Tool (QUADAS-2).

STUDY SELECTION

Of the 1,465 records identified, 29 references were selected to perform qualitative analysis. The study characteristics were tabulated in a self-designed table. QUADAS-2 tool identified 10 and 15 studies to respectively have a high and an unclear risk of bias, while only four were categorized as low risk of bias. Overall, accuracy rates for dental implant classification ranged from 67 % to 99 %. Peri-implant pathology identification showed results with accuracy detection rates over 78,6 %.

CONCLUSIONS

While AI-based models, particularly convolutional neural networks, have shown high accuracy in dental implant classification and peri-implant pathology detection, several limitations must be addressed before widespread clinical application. More advanced AI techniques, such as Federated Learning should be explored to improve the generalizability and efficiency of these models in clinical practice.

CLINICAL SIGNIFICANCE

AI-based models offer can and clinicians to accurately classify unknown dental implants and enable early detection of peri-implantitis, improving patient outcomes and streamline treatment planning.

Maintenance Costs, Time, and Efforts Following Implant Therapy With Fixed Restorations Over an Observation Period of 10 Years: A Randomized Controlled Clinical Trial

OBJECTIVES

To assess the costs and efforts of maintenance therapy following implant treatment with fixed restoration over an observation period of 10 years.

MATERIAL AND METHODS

This randomized controlled clinical trial included 64 patients who were randomly assigned to receive one of two implant systems (AST or STM) and fixed restoration. Patients were included in a regular maintenance program and were examined at loading, 1, 3, 5, 8, and 10 years. Outcome measures included technical and biological complications, time, efforts, and costs to resolve them.

RESULTS

A total of 97 implants were placed in 64 patients (AST: 54, STM: 43). Patient recall rates at 5 and 10 years were 89% and 67%. In general, technical complications were resolved within one to two appointments (mean = 1.5), and biological complications required a mean of 1.3 appointments. The overall regular maintenance time for the period of 10 years amounted to 77 min per year. Technical complications occurred in 39.5% of the patients, with screw-loosening being the most common one (43.4% of all complications). The most time-consuming technical complication was abutment fracture (94 min ± 68), followed by screw fracture (84 min ± 38). The prevalence of peri-implant mucositis on the patient level was 30.2%, and it was 9.3% for peri-implantitis. The average annual maintenance costs amounted to 9% of the initial cost of the implant treatment over the period of 10 years.

CONCLUSIONS

Additional regular maintenance costs and costs due to the treatment of potential complications have to be taken into consideration when placing dental implants. The majority of technical complications could be resolved within one appointment, whereas the time needed to treat biological complications varied between one and three appointments for peri-implantitis.

A 10-year Retrospective Clinical Study to Identify Risk Indicators for Peri-Implant Bone Loss and Implant Failure

AIM

To evaluate long-term survival and success of dental implants and evaluate indicators affecting the long-term outcome.

MATERIALS AND METHODS

Implant survival, success and crestal bone loss (BL) over time were evaluated. For covariates at patient level, Kaplan-Meier estimates of implant survival were compared between groups with the log-rank test. Observed mean bone loss (MBL) was plotted as a function of time. Cumulative frequencies of BL were plotted for different post-op times. Uni- and multivariate analysis was performed. Simple linear mixed and multiple linear mixed models for BL at 1, 5 and 10 years were fitted.

RESULTS

407 patients (221 women, 186 men; mean age 64.86 years (range 28-92, SD 10.11)), with 1482 implants, responded. Absolute implant survival was 94.74%; MBL was 0.81 mm (SD 1.58, range 0.00-17.00) after an average follow-up of 10.66 years (range 10-14, SD 0.87). Implant survival was influenced on implant level by smoking, implant width and early bone loss (EBL) > 0.5 mm; on patient level by a history of periodontitis. Indicators influencing MBL after the 1st year were abutment height, type of surgery and implant width, while after 5 and 10 years of function were abutment height, EBL > 0.5 mm and smoking.

CONCLUSION

Implant survival was significantly affected by a history of periodontitis on patient level and by smoking, implant width and EBL > 0.5 mm on implant level. Late bone loss was significantly affected by abutment height, EBL > 0.5 mm and smoking.

TRIAL REGISTRATION

B670201524796.

Factors Influencing the Screw Stability of Implant-Supported Single Crowns: An In Vitro Study

The aim is to investigate the impact of retention type, implant/abutment angulation, and the presence of sealant/antimicrobial agents on screw loosening of implant-supported restorations. Fifty dental implants along with their respective abutments and screws were allocated to five groups (n = 10). The groups were categorized based on type of crown retention (screw-/cement-retained), implant/abutment angulation (0°/20°), and type of disinfectant/sealant as follows: Cem_control (cemented/0°/none), Cem_GP (cemented/0°/gutta-percha), Cem_CHX (cemented/0°/chlorhexidine), Cem_Ang (cemented/20°/none), and Screw (screwed/0°/ none). Abutment screws were tightened (20 Ncm), and CAD/CAM zirconia crowns were fabricated. Glass ionomer cement was used for crown cementation in the cemented groups. Samples were subjected to dynamic loading in a chewing simulator (1,200,000 cycles/98 N). After loading, the reverse torque values (RTVs) of the abutment screws were determined (Ncm) using an electronic screwdriver, and the reverse torque difference (RTD) was subsequently calculated. The lowest RTD was reported in group Cem_GP (-2.22 ± 1.03), whereas the highest RTD was seen in group Screw (-4.65 ± 1.79). Group Screw showed a statistically significant difference from all other groups (p < 0.05). No statistically significant difference between the cemented test groups Cem_GP, Cem_CHX, and Cem_Ang and the control group was found. Screw-retained restorations exhibited significantly greater RTD values compared to cement-retained ones. Implant/abutment angulation and the sealant/disinfectant appeared to have no notable effect on the screw stability of single-implant restorations.

In vitro cytotoxicity of dental implant cements on human gingival and mouse preosteoblast cell lines

PURPOSE

This study aims to evaluate the cytotoxicity of implant luting cements and to visualize the morphological changes in the cells.

METHODS

Seven experimental groups Cem Implant Cement (CIC), EsTemp Implant Cement (EIC), Harvard Implant Cement (HIC), MIS Crown Set Implant Cement (MCIC), Oxford Cem Implant Cement (OCIC), Premier Implant Cement (PIC), and Adhesor Carbofine (ZPC) were generated including one conventional, and six implant cements (n = 9). Specimens were applied to human fibroblast cell (HGF) and mouse pre-osteoblast cell line (MC3T3-E1) cells by direct contact and extract text methods. The extracts were prepared by sterilizing the discs under ultraviolet light for 24 h in a cell culture medium at 37°C, 5% CO, and 95% humidity. Cell lines were confluent in the cell culture module in 25 cm² and 75 cm² flasks in a carbon dioxide incubator with 5% CO and 95% humidity. Discs and extracts were placed in a 96-well plate. Cell viability was evaluated after 24 h by means of a cell proliferation assay with 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxyanilide (XTT assay).

RESULTS

Dual-cured OCIC and HIC cements comprising methacrylate and zinc oxide elicited relatively lower cytotoxicity than self-cure cements with various compositions. The OCIC revealed the highest cell viability (89%) in the extract method on the HGF cells. Immortalized MC3T3 cells showed more sensitivity to cement exposure than the primary HGF cells.

CONCLUSION

All tested cements elicited a cytotoxic effect with differences depending on cell type and cement material in extract and direct contact methods. Dual polymerized semi-permanent cement (OCIC) showed higher cell viability in the extract method.

Pull-Off Forces on Implant-Supported Single Restorations by Sticky Food: An In Vitro Study

OBJECTIVE

To investigate the pull-off forces on implant-supported restorations caused by sticky food, to understand how much retention force cemented restorations must have to withstand chewing forces without unintentional retention loss. The influence of food type, restoration design, and surface treatment were investigated.

MATERIAL AND METHODS

Monolithic implant-supported CAD/CAM zirconia crowns were fabricated and divided into groups according to their design: no (NC), flat (FC) and high cusps (HC) and subdivided according to surface roughness: rough (r) and smooth (s) (n = 10/group). NC represented the control group. The crowns were fixed in a universal testing machine opposite to each other. Four sticky foods (caramel, fruit jelly, candy strips and licorice) and a resin crown remover were tested. These were heated (36.4°C), placed between the crowns and compressed, then tensile strength tests were performed. The maximum pull-off force was recorded (Newton [N]). Statistical analysis was performed using 3-way ANOVA.

RESULTS

The highest mean pull-off force among food samples was with caramel_HC_r (12.09 ± 1.26 N), whereas the lowest was with licorice_FC_s (3.21 ± 0.15 N). For the resin crown remover, a mean pull-off force of 55.41 ± 3.87 N was measured in the HC_r group. Both food type and crown design showed a significant influence on pull-off force (p < 0.001), whereas no significant effect was reported with different surface roughnesses (p = 0.344).

CONCLUSION

This study reported pull-off forces of up to 20 N between all-ceramic restorations caused by sticky food. The clinical implication of these findings is that a cemented implant-restoration must have a minimum retention force of 20 N to withstand unintentional displacement during function.

The Modified Coronally Advanced Tunnel Technique for Coverage of Mucosal Recessions at Dental Implants

OBJECTIVES

To clinically evaluate the outcomes following surgical coverage of single peri-implant mucosal recessions in the aesthetic maxillary area by means of the modified coronally advanced tunnel (MCAT) and subepithelial connective tissue graft (SCTG).

MATERIALS AND METHODS

Eleven systemically healthy non-smoking patients (8 females) each presenting a single peri-implant mucosal recession in the anterior maxillary region were consecutively treated with MCAT in conjunction with SCTG. In all cases, the facial recession was associated with an impaired aesthetic appearance. Before reconstructive surgery and at 12 months postoperatively, clinical and aesthetic parameters were assessed. The primary outcome variable was the mean mucosal recession coverage (MRC).

RESULTS

Healing was uneventful in all cases. At 12 months, statistically significant (p < 0.05) recession coverage (MRC 94.71%) and improvement of aesthetics (pink aesthetic score) was obtained at all implants. Complete RC was obtained in 10 out of the 11 patients (90.9%). The treatment was associated with a statistically significant gain of keratinized and attached mucosa (p < 0.05).

CONCLUSION

The present results demonstrate that single peri-implant mucosal recessions in the maxillary aesthetic area can be successfully treated with MCAT and SCTG.

A Biomechanical Comparative Analysis of Abutment Screw Head Designs on Preload Stability Under Oblique Compressive Forces: An In Vitro Pilot Study

The purpose of this study was to examine the impact of abutment screw head sizes on preload stability when secured to a standard external hex implant under oblique compressive forces. Fifteen metal crowns were divided into 3 equal groups. The first group had 5 angulated cemented crowns connected to a 3-mm-tall straight hexagonal abutment with an external hex abutment screw. The second and third groups each had 5 straight cemented crowns attached to a tapered abutment with flat-slotted and internal hex abutment screws, respectively. Samples were subjected to a static cyclic load until failure. Kruskal-Wallis H, Dunn, and one-way analysis of variance with Tukey honestly significant difference tests were performed. Cemented straight crowns supported by an angled abutment connected to implants with flat-slotted and internal hex abutment screw heads failed at an average of 4.24 × 106 cycles ± 3.31 SD and 12.67 × 106 cycles ± 5.47 SD, respectively. Cemented angled crowns supported by a straight abutment connected to identical implants with an external hex abutment screw survived 18.02 × 106 cycles ± 4.49 SD. The periotest value rate of change increased at a higher rate in crowns supported by angled abutments compared with straight abutments (p < .05). No cement failure was observed. Under the experimental conditions, larger abutment screw head sizes demonstrated greater stability of the abutment-abutment screw joint interface. Based on the in vitro findings, no cement failure was observed between the cemented crown and abutment connection. Future research with standardized comparative setups and larger sample sizes is needed.

Enhancing oral function: A case report on mandibular overdenture utilization with custom-made subperiosteal implant

Subperiosteal implants, previously set aside because of complications, are now emerging again as effective treatments for severe mandibular atrophy, aided by recent improvements in digital dentistry. Traditional dentures in such cases often face challenges with support and retention, necessitating complex regenerative procedures. This paper presents a case report of a 54-year-old male patient with significant mandibular atrophy who received a custom-made subperiosteal implant, showcasing promising results. The implant was precisely designed utilizing computed tomography (CT) scans, a 3D-printed model, the selective laser melting (SLM) technique, and constructed with biocompatible Ti6Al4V material. This innovative approach offered a practical solution, resulting in high patient satisfaction and no complications over a year of use.

Four-mm-short implants in the rehabilitation of posterior atrophic jaws: A retrospective study on 212 patients with a mean follow-up of 8.02 years

OBJECTIVE

This study aimed to assess clinical efficacy of 4-mm-short implants in patients with posterior severe vertical bone atrophy in the medium- and long-term follow-up.

MATERIALS AND METHODS

Patients rehabilitated with 4-mm-short implants in the posterior atrophic jaws, with a minimum follow-up of 3 years post-loading, were included in the study. Data were collected for eligible patients, and marginal bone loss (MBL) for each implant was evaluated. The research outcomes were implant failure, MBL and complications.

RESULTS

A total of 212 patients with 496 implants were included, resulting in a mean follow-up of 8.02 ± 2.17 years. The implant survival rate was 95.36% (95% CI: 93.12%-97.04%). More implant failures were observed in the maxilla (p = .02) and fewer failures were observed in patients undergoing more number of hygienic sessions per year (p < .001). The average MBL after 1-year-loading was 0.47 mm, increasing to 0.59 mm after 10 years; after 3 years no statistically significant increase in MBL was observed. Maxillary implants showed greater bone loss than mandibular ones (p < .001). More frequent professional oral hygiene sessions per year resulted being related with reduced MBL (p < .001).

CONCLUSIONS

Four-mm-short implants showed high survival rates with an up to 10-year follow-up. Their use can offer a fixed prosthetic solution for patients with posterior vertical bone atrophy, minimizing surgical invasiveness, rehabilitative times and costs.

Evaluation of two different occlusal patterns on single posterior implant-supported crowns: A 12-month prospective study of occlusal analysis

STATEMENT OF PROBLEM

According to the concept of implant-protected occlusion, light occlusion and late contact could prevent implants from occlusal overload. However, clinical data demonstrating how light occlusion differs from normal occlusion are lacking.

PURPOSE

The purpose of this prospective clinical study was to characterize the occlusal variation of single posterior implant-supported crowns with or without light occlusion.

MATERIAL AND METHODS

Participants with a single missing posterior maxillary or mandibular molar who were to receive implant-supported zirconia ceramic crowns were enrolled. The participants were divided into a light occlusion group, in which a 12-μm articulating film could be removed from the implant-supported crown and opposing natural teeth under the intercuspal position, and a normal occlusion group, in which the articulating film could not be removed. All participants underwent occlusal examinations using the T-scan III system, answered a satisfaction questionnaire using a visual analog scale (VAS), and received regular follow-ups. The participants were evaluated at 0.5, 3, 6, and 12 months after implant-supported crown delivery. The relative occlusal force of the implant-supported crowns, mesial teeth, control teeth (corresponding natural tooth on the dentition contralateral to each implant), and the occlusal contact time of implant-supported crowns were recorded. Moreover, the asymmetry index of the occlusal force and the VAS score were calculated. Two independent-sample tests were used to compare the 2 groups. The Wilcoxon rank sum and Mann‒Whitney tests were used to compare nonnormally distributed data (α=.001).

RESULTS

Fifty study participants with a mean ±standard deviation age of 36.97 ±7.34 years (23 men and 27 women aged 20 to 50 years) were followed for 0.5 to 12 months. No obvious complications of overloading were observed in either group. The mean ±standard deviation of the relative occlusal force of implant-supported crowns in the light occlusion group (from 4.91 ±3.52% to 10.34 ±4.35%) was always lower than that in the normal occlusion group (from 10.45 ±4.32% to 18.15 ±4.80%), while the mean ±standard deviation of the occlusal contact time in the light occlusion group (from 0.38 ±0.26 seconds to 0.10 ±0.07 seconds) was significantly later than that in the normal occlusion group (from 0.12 ±0.08 seconds to 0.04 ±0.02 seconds) (P<.001). The value of the asymmetry index of occlusal force remained within the normal range (10%). The VAS score in the normal occlusion group was significantly higher than that in the light occlusion group (P<.001).

CONCLUSIONS

Providing light occlusion to reduce occlusal force and delay the contact time was not stable over time. The relative occlusal force and occlusal contact time showed a similar development trend in both groups, and no obvious signs of occlusal overloading were observed in this study. Long-term follow-up is necessary for implant-supported prostheses because of the continuous increase in occlusal force.

Treatment strategies for dental implant removal: A literature review

Dental implants have been widely used with success, but long-term usage sometimes leads to implant loss. The purpose of this review was to summarize the etiology of early and late failure requiring dental implant removal and the treatment strategies for the removal of failed implants and reimplantation. Early failures are often caused by patient-related factors, such as smoking, diabetes, radiotherapy, bone quality, and periodontitis of the remaining natural teeth. The most common cause of late failure is peri-implantitis, followed by implant fracture and implant malpositioning. Implants should be removed if they are mobile or if their superstructure cannot be maintained (e.g., implant fracture). For peri-implantitis, implant removal should be determined based on the patient's age and esthetic needs, the implant site, and the severity of bone loss. Many reports have been published on implant removal techniques. The reverse torque technique should always be the first choice because of its low invasiveness. The weighted survival rate for the replacement of failed implants is 86.3%, with a much lower survival rate after the second or subsequent implantations. Therefore, patient-specific problems, such as smoking habits and bruxism, should be checked before reimplantation and controlled to the greatest extent possible.

A New Multi-Axial Functional Stress Analysis Assessing the Longevity of a Ti-6Al-4V Dental Implant Abutment Screw

This study investigates the impact of tightening torque (preload) and the friction coefficient on stress generation and fatigue resistance of a Ti-6Al-4V abutment screw with an internal hexagonal connection under dynamic multi-axial masticatory loads in high-cycle fatigue (HCF) conditions. A three-dimensional model of the implant-abutment assembly was simulated using ANSYS Workbench 16.2 computer aided engineering software with chewing forces ranging from 300 N to 1000 N, evaluated over 1.35 × 107 cycles, simulating 15 years of service. Results indicate that the healthy range of normal to maximal mastication forces (300-550 N) preserved the screw's structural integrity, while higher loads (≥800 N) exceeded the Ti-6Al-4V alloy's yield strength, indicating a risk of plastic deformation under extreme conditions. Stress peaked near the end of the occluding phase (206.5 ms), marking a critical temporal point for fatigue accumulation. Optimizing the friction coefficient (0.5 µ) and preload management improved stress distribution, minimized fatigue damage, and ensured joint stability. Masticatory forces up to 550 N were well within the abutment screw's capacity to sustain extended service life and maintain its elastic behavior.

Microarchitectural Study of the Augmented Bone Following a Modified Ridge Splitting Technique: Histological and Micro-Computed Tomography Analyses

Objectives: The aim of this matched prospective cohort study was to examine the microarchitecture of the augmented bone following a modified alveolar ridge splitting procedure and compare it to that of native bone. Methods: In the test group, patients underwent a modified ridge split osteotomy procedure to restore the width of the posterior segment of the mandible. Patients with sufficient bone width for dental implant placement in the posterior region of the mandible following 3-month-long spontaneous healing after tooth removal were included in the control group. In both study groups, bone biopsy samples were harvested and dental implants were placed. Histomorphometry and micro-CT analysis were performed. Results: Altogether, 15 patients were included in this study (7 patients in the test group, with 14 bone core biopsies harvested, and 8 patients in the control group, with 13 bone core biopsies harvested). Percentage bone volume (BV/TV) in the micro-CT analysis (22.088 ± 8.094% and 12.075 ± 4.009% for the test and control group, respectively) showed statistically significant differences between study groups. Conclusions: Based on histological and micro-CT analyses, the modified ridge splitting procedure with autologous bone block harvested from the retromolar area results in a dental implant recipient bone microarchitecture superior to that of the extraction sockets left to heal undisturbed for a 3-month-long healing period.

Monolithic zirconia as a valid alternative to metal-ceramic for implant-supported single crowns in the posterior region: A systematic review and meta-analysis of randomized controlled trials

STATEMENT OF PROBLEM

Technical complication rates of standard metal-ceramic implant-supported posterior restorations are relatively high. Whether monolithic zirconia crowns represent a more successful alternative is unclear.

PURPOSE

The purpose of this systematic review and meta-analysis was to compare the clinical outcomes of posterior monolithic zirconia and metal-ceramic implant-supported single crowns.

MATERIAL AND METHODS

A search was conducted in MEDLINE, Scopus, Embase, Web of Science, and CENTRAL databases for randomized controlled trials up to April 2023 with a follow-up time of at least 1 year. Restoration and implant survival and failure rates, marginal bone loss (MBL), bleeding on probing (BOP), and technical complications were analyzed by 2 reviewers. Statistical analyses were conducted using the R-statistics software program. The risk of bias was assessed by the Cochrane Risk of Bias Tool 2 (RoB 2), and the certainty of evidence by the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

A total of 11 out of 2030 records were identified by title and abstract, and 4 records were included after full-text analysis. The statistical analysis revealed no significant difference in MBL (MD -0.11, 95% CI: [-0.25; 0.03]), BOP (OR 0.66, 95% CI: [0.25; 1.77]), or implant failure (OR 1.30, 95% CI: [0.24; 7.08]). Monolithic zirconia presented significantly less chipping over 1 year (OR 0.17, 95% CI: [0.03; 0.99]). The chipping rate was 0% for monolithic zirconia and 7.61% for metal-ceramic. Based on a narrative review, the restoration survival rate was 97.5% in the monolithic zirconia group and 99.1% in the metal-ceramic group.

CONCLUSIONS

Monolithic zirconia showed favorable short-term survival rates and had significantly less chipping over 1 year. Regarding MBL, BOP, and failure rates, both restoration types presented similar results at the 1-year follow-up.

Understanding immune-mediated titanium allergy to in situ orthopaedic implants: a narrative review of the current literature

INTRODUCTION

Clinical recognition of potential immune-mediated allergic responses to implanted metal devices is increasing. For orthopaedic implants, while 'pure' compounds are used in specific circumstances, the majority of components are alloys - a combination of two or more distinct metals. Titanium is found commonly in many orthopaedic devices and is often championed as a 'hypoallergenic' option or inclusion. In the absence of a relevant previously published summary on the topic, this paper explores the current state-of-understanding of titanium allergy and proposes a patient management algorithm whereby such immune reactions are clinically-suggested.

METHODS

A structured, systematic literature review was performed following PRISMA search principles to provide a contemporary summary-of-understanding in this area and to highlight clinical and knowledge deficiencies.

RESULTS

Thirty-five topic-related articles were identified, the majority reflecting small case series' or proof-of-concept studies. The general standard of scientific evidence available was poor. Justification for arthroplasty utilization of titanium as a 'hypoallergenic' option is largely extrapolated from non-orthopaedic domains.

CONCLUSIONS

Both ionic and conjugated titanium particles released from implant surfaces have the potential to trigger innate immune responses and true allergy. There exists no simple, high-sensitivity, screening test for titanium allergy. Conventional skin-patch testing is unreliable due to poor dermal penetration. Given established lymphocyte and macrophage activation pathways for allergy responses, in vitro methods using both cell-types show diagnostic promise. Surgical biopsy analysis from host-implant interfaces remains the contemporary 'gold-standard', however this represents an invasive, costly and highly-specialized approach not readily available in most settings. Further research to establish reliable/accessible diagnostic methods are indicated.

Effect of soft tissue thickness on accuracy of conventional and digital implant impression techniques

BACKGROUND

Placing implants deep sub-gingivally may affect the accuracy of implant impression techniques and the fit of final restoration.

PURPOSE

The aim of this in-vitro study was to evaluate the effect of soft tissue thickness on accuracy of conventional and digital implant impression techniques.

METHODS

Four parallel implant analogues (A, B, C, D) placed in each of two epoxy resin models representing edentulous mandible covered by flexible polyurethane material with two different thickness two mm and four mm. A total of sixty impressions performed, thirty impressions for each model divided into four groups (n = 15 per group) GI (C2mm) open tray impression with two mm implant depth, GII (C4mm) open tray impression with four mm implant depth, GIII (D2mm) digital impression with two mm implant depth, GIV (D 4 mm) digital impression with four mm implant depth. Impressions from open tray technique were poured to get stone casts while impressions from digital scanning technique were printed as three-dimensional printed casts. The six inter-implant distances between analogues were measured using Co-ordinate measuring machine, deviations compared to reference models were calculated. Data was collected, tabulated and statistically analyzed using One-way ANOVA test to detect significances between groups.

RESULTS

For conventional impressions there was significant difference between C2mm/C4mm (P < 0.001) regarding interimplant distance, while in digital impressions there was no significant difference between D2mm/D4mm AB(p = 0.110), BC(p = 0.066), CD(p = 0.710), AD(p = 0.084), AC(p = 0.067) and BD(p = 0.072). There was significant difference between conventional and digital impression techniques C2mm/D2mm, C4mm/D4mm (P < 0.001).

CONCLUSION

Within the limitations of this in-vitro study digital impressions provide more accurate outcomes with implants placed deeper subgingivally than conventional impressions.

TRIAL REGISTRATION

Retrospectively registered.

Coating Materials to Prevent Screw Loosening in Single Dental Implant Crowns: A Systematic Review

Oral rehabilitation with dental implants has resulted in high success rates. However, some complications have been described, such as the loss of the prosthetic screw. Some manufacturers sell screws with different coatings to avoid screw loosening, but even these types of screws can come loose. We aimed to investigate the screw coatings that can be applied during a dental appointment to avoid screw loosening. Following PRISMA Guidelines, we searched PubMed/Medline, Embase and Web of Science for studies published up to January 2024. All studies of single dental implant crowns, in which the prosthetic screw was coated with a lubricant and the preload and/or the removal torque value (RTV) was recorded, were analyzed. We excluded studies applying the finite element method (FEM) as well as studies without a control group. The risk of bias was assessed with a tool developed by our research group. Of the 1959 records identified, 19 were selected. Ten studies were considered to have a low risk of bias, and nine were considered to have a medium risk of bias. The coatings tested were adhesives, saliva, chlorhexidine, Vaseline, silicone gel, Polytetrafluoroethylene (PTFE) tape, blood, fluoride, Listerine® Mouthwash and normal saline. The preload, the RTV with and without cyclic loading and the percentage of RTV loss were recorded. Some coatings show promise, although there is no clear evidence that any option is superior in minimizing screw loosening.

Partial fixed dental prostheses fabricated using fiber-reinforced composite resin supported by short and extra-short implants: A case series

PURPOSE

This study aimed to evaluate the 10-year outcomes of partial fixed dental prostheses (P-FDPs) fabricated using metal-free fiber-reinforced composite (FRC) resin frameworks veneered with composite resin and supported by short and extra-short implants.

METHODS

This study included 28 patients with 38 FRC prostheses supported by 96 implants. Implant and prosthesis survival and success rates were evaluated using Kaplan-Meier analysis.

RESULTS

The 10-year implant survival and success rate, as determined by Kaplan-Meier analysis, was 96.9%, and the prosthesis survival and success rates were 94.7% and 92.0%, respectively. None of the parameters under investigation were significantly correlated with prosthetic survival or successful outcomes, but three parameters were correlated with higher peri-implant bone levels: implant placement in the mandible as opposed to the maxilla, shorter P-FDP spans, and natural teeth on the opposing arch.

CONCLUSIONS

FRC P-FDPs supported by short and extra-short implants presented high, up to 10-year, survival and success rates, when used to restore partially edentulous arches.

How far can we go? A 20-year meta-analysis of dental implant survival rates

OBJECTIVE

This meta-analysis aims to investigate the long-term survival rates of dental implants over a 20-year period, providing a practical guide for clinicians while identifying potential areas for future research.

MATERIALS AND METHODS

Data were sourced from recent publications, focusing exclusively on screw-shaped titanium implants with a rough surface. Both retrospective and prospective studies were included to ensure an adequate sample size. A systematic electronic literature search was conducted in the databases: MEDLINE (PubMed), Cochrane, and Web of Science. The risk of bias for all studies was analyzed using a tool by Hoy et al. RESULTS: Three prospective studies (n = 237 implants) revealed a mean implant survival rate of 92% (95% CI: 82% to 97%), decreasing to 78% (95% CI: 74%-82%) after imputation (n = 422 implants). A total of five retrospective studies (n = 1440 implants) showed a survival rate of 88% (95% CI: 78%-94%). Implant failure causes were multifactorial.

CONCLUSION

This review consolidates 20-year dental implant survival data, reflecting a remarkable 4 out of 5 implants success rate. It emphasizes the need for long-term follow-up care, addressing multifactorial implant failure. Prioritizing quality standards is crucial to prevent overestimating treatment effectiveness due to potential statistical errors. While dental implantology boasts reliable therapies, there is still room for improvement, and additional high-quality studies are needed, particularly to evaluate implant success.

CLINICAL RELEVANCE

Never before have the implant survival over 20 years been systematically analyzed in a meta-analysis. Although a long-term survival can be expected, follow-up is essential and shouldn't end after insertion or even after 10 years.

Influence of Connector Design on Displacement and Micromotion in Tooth-Implant Fixed Partial Dentures Using Different Lengths and Diameters: A Three-Dimensional Finite Element Study

The literature presents insufficient data evaluating the displacement and micromotion effects resulting from the combined use of tooth-implant connections in fixed partial dentures. Analyzing the biomechanical behavior of tooth-implant fixed partial denture (FPD) prothesis is vital for achieving an optimum design and successful clinical implementation. The objective of this study was to determine the relative significance of connector design on the displacement and micromotion of tooth-implant-supported fixed dental prostheses under occlusal vertical loading. A unilateral Kennedy class I mandibular model was created using a 3D reconstruction from CT scan data. Eight simulated designs of tooth-implant fixed partial dentures (FPDs) were split into two groups: Group A with rigid connectors and Group B with non-rigid connectors. The models were subjected to a uniform vertical load of 100 N. Displacement, strain, and stress were computed using finite element analysis. The materials were defined as isotropic, homogeneous, and exhibiting linear elastic properties. This study focused on assessing the maximum displacement in various components, including the bridge, mandible, dentin, cementum, periodontal ligament (PDL), and implant. Displacement values were predominantly higher in Group B (non-rigid) compared to Group A (rigid) in all measured components of the tooth-implant FPDs. Accordingly, a statistically significant difference was observed between the two groups at the FPD bridge (p value = 0.021 *), mandible (p value = 0.021 *), dentin (p value = 0.043 *), cementum (p value = 0.043 *), and PDL (p value = 0.043 *). Meanwhile, there was an insignificant increase in displacement values recorded in the distal implant (p value = 0.083). This study highlighted the importance of connector design in the overall stability and performance of the prosthesis. Notably, the 4.7 mm × 10 mm implant in Group B showed a displacement nearly 92 times higher than its rigid counterpart in Group A. Overall, the 5.7 mm × 10 mm combination of implant length and diameter showcased the best performance in both groups. The findings demonstrate that wider implants with a proportional length offer greater resistance to displacement forces. In addition, the use of rigid connection design provides superior biomechanical performance in tooth-implant fixed partial dentures and reduces the risk of micromotion with its associated complications such as ligament overstretching and implant overload, achieving predictable prognosis and enhancing the stability of the protheses.

Rehabilitation of an Atrophied Upper Maxillary Arch With an Implant-Supported Hybrid Prosthesis

In a completely edentulous situation, providing a fixed hybrid prosthesis with the support of dental implants could be one of the viable treatment options. Such type of hybrid prosthesis is fabricated by applying the heat-cured polymerized resin over the metal framework and screwing the complete assembly into the implants. The objective of this case report is to illustrate the rehabilitation of the form, function, and esthetics of an atrophied upper maxillary arch by utilizing an implant-supported hybrid prosthesis.

An Atypical Way of Restoring an Internally Mangled Implant With the Use of a Cast Post: A Case Report

Implant-supported prostheses can lead to biological or mechanical failures. The loosening of the abutment screw and its fracture are the most common technical complications. Recovery of fractured parts is quite challenging due to the unavailability of a universal standard screw retrieval kit on the market. Various techniques have been described earlier for retrieval of fractured fragments or internal thread damage, but with no optimum success and eventually leading to implant failure and removal, which causes additional surgical exposure and economic impediment. Hence, this clinical report explains the viable option for such a situation using an alternative technique and simple armamentarium available in regular clinic setups.

Prosthetic Complications of Single Screw-Retained Implant-Supported Metal-Ceramic Fixed Prostheses: A Retrospective Observational Study

Purpose

To analyze prosthetic complications of single screw-retained implant-supported metal-ceramic fixed prostheses (SSIMCFPs).

Materials and Methods

A total of 457 medical records of patients treated with implants at the University Dental Clinic of the European University of Valencia from 2016 to 2022 were reviewed. Of the 335 SSIMCFPs evaluated, 222 were included. The following data were collected from medical records: age, sex, prosthesis location, implant diameter, type of antagonist, date of prosthesis placement, type of prosthetic complications, and the date of the occurrence of complications. Statistical analysis was estimated at the patient level with a simple binary logistic regression and at the prosthesis level, a simple logistic regression with generalized estimating equation models (p  < 0.05).

Results

A total of 222 SSIMCFPs were placed in 159 patients. The prevalence of complications was 23.3% at the patient level, equivalent to 21.6% of SSIMCFPs. A total of 48 complications were collected; screw loosening was the most frequent complication (16.2%), followed by ceramic fracture (3.1%), screw fracture (1.8%), and implant fracture (0.5%). There were no cases of abutment fracture. The mean time of the loosening of the screw was 10.5 months and ceramic fractures at 6.9 months. The factors that most influenced the occurrence of prosthetic complications were posterior position (p  < 0.001), implant diameter from 3.5 to 4.8 mm (p  < 0.01), and lower arch position (p  < 0.05).

Conclusions

The most frequent complication of SSIMCFP was loosening of the screw followed by ceramic fracture. The appearance of these complications usually occurred during the first year after SSIMCFP placement. Factors related to the occurrence of complications were mandibular posterior location and implant diameter from 3.5 to 4.8 mm.

Peri-Implantitis

Peri-implantitis can affect the longevity of successfully integrated implants. Implant success is dependent on reducing the peri-implantitis risk or successfully managing peri-implantitis. Further understanding of peri-implantitis can be derived from its prevalence, microbial and diagnostic findings, existing therapies, and the effects of systemic health issues and medication. Based on published information: (1) peri-implantitis is higher in patients who have periodontitis or smoke as well as in implants with 5 years of function; (2) peri-implantitis microflora is different from periodontitis; (3) peri-implantitis risk is increased in patients with cardiovascular diseases and uncontrolled diabetes; (4) most reported peri-implantitis therapies may result in resolution, but the best peri-implantitis treatment is still to be determined; (5) more frequent peri-implant maintenance may reduce risk for peri-implantitis.

Single Dental Implant Restoration: Cemented or Screw-Retained? A Systematic Review of Multi-Factor Randomized Clinical Trials

Background: Dental implant rehabilitation has significantly advanced prosthodontics by providing a reliable, long-lasting solution for missing teeth. This systematic review compares the clinical, technical, and biological outcomes of cemented versus screw-retained single dental implant restorations based on randomized clinical trials (RCTs). Materials and Methods: This review included recent human and in vitro studies focusing on the keywords “cemented vs. screw-retained” and “dental implant”. Eight studies met the inclusion criteria, which investigated parameters, including implant survival rate, bleeding on probing (BOP), probing depth, plaque index, marginal bone loss (MBL), cytokine concentrations, mechanical complications, esthetic outcomes, patient satisfaction, treatment time, and technical failures. Results: The primary outcomes, BOP and MBL, did not statistically differ between cemented and screw-retained implants (p-values for MBL and BOP are 0.5813 and 0.8093, respectively). The reviewed studies, including RCTs, split-mouth studies, and clinical evaluations, demonstrated comparable clinical, technical, and biological outcomes between the two restoration methods. Conclusions: Screw-retained and cemented dental implant restorations exhibit similar clinical, technical, and biological outcomes. Screw-retained restorations offer advantages such as retrievability, ease of repair, and predictable passive fit, while cemented restorations provide superior esthetics. The risk of peri-implant complications due to residual cement in cemented restorations must be considered. Future research should explore long-term stability and the impact of different prosthetic protocols on peri-implant health.

Effect of hydroxyapatite nanoparticles coating of titanium surface on biofilm adhesion: An in vitro study

AIM

To evaluate the adhesion of mono and duospecies biofilm on a commercially available dental implant surface coated with hydroxyapatite nanoparticles (nanoHA).

MATERIAL AND METHODS

Titanium discs were divided into two groups: double acid-etched (AE) and AE coated with nanoHA (NanoHA). Surface characteristics evaluated were morphology, topography, and wettability. Mono and duospecies biofilms of Streptococcus sanguinis (S. sanguinis) and Candida albicans (C. albicans) were formed. Discs were exposed to fetal bovine serum (FBS) to form the pellicle. Biofilm was growth in RPMI1640 medium with 10% FBS and 10% BHI medium for 6 h. Microbial viability was evaluated using colony-forming unit and metabolic activity by a colorimetric assay of the tetrazolium salt XTT. Biofilm architecture and organization were evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM).

RESULTS

AE surface had more pores, while NanoHA had even nanoHA crystals distribution. Roughness was similar (AE: 0.59 ± 0.07 µm, NanoHA: 0.69 ± 0.18 µm), but wettability was different (AE: Θw= 81.79 ± 8.55°, NanoHA: Θw= 53.26 ± 11.86°; P = 0.01). NanoHA had lower S. sanguinis viability in monospecies biofilm (P = 0.007). Metabolic activity was similar among all biofilms. In SEM both surfaces on C. albicans biofilm show a similar distribution of hyphae in mono and duospecies biofilms. AE surface has more S. sanguinis than the NanoHA surface in the duospecies biofilm. CLSM showed a large proportion of live cells in all groups.

CONCLUSIONS

The nanoHA surface reduced the adhesion of S. sanguinis biofilm but did not alter the adhesion of C. albicans or the biofilm formed by both species.

Restoring Oral Health: Implant-Supported Full-Mouth Rehabilitation for an Edentulous Patient

Edentulism, the loss of all the natural teeth, significantly impacts a patient's functional, aesthetic, and psychological well-being. Traditional dentures often fail to provide the required stability and functionality. Implant-supported full-mouth rehabilitation has emerged as an advanced solution, leveraging strategically placed dental implants to support fixed prostheses that mimic natural teeth in appearance and function. This case report details the comprehensive treatment of a 78-year-old male patient with complete edentulism, utilizing six implants in both the maxillary and mandibular arches. Following a five-month healing period, a series of precise prosthetic procedures, including abutment-level impressions, custom tray fabrication, and implant-level impressions, were performed to ensure optimal fit and functionality. The final prostheses provided significant improvements in masticatory efficiency, speech, and overall quality of life. The report underscores the transformative potential of implant-supported rehabilitation, highlighting high success rates, patient satisfaction, and the multifaceted benefits of restoring oral function and aesthetics with advanced dental technologies.

Cost-Effectiveness Analysis of Implant-Supported Single Crown and Tooth-Supported Fixed Dental Prostheses in Türkiye

OBJECTIVES

The most cost-effective option for replacing lost teeth is not evident because there is a dearth of evidence-based information on implant-supported single crowns versus tooth-supported fixed dental prostheses. This study conducted the analysis of cost-effectiveness of implant-supported single crown and tooth-supported fixed dental prostheses from a social perspective in Türkiye.

METHODS

Costs were calculated in the analysis from a social perspective for 2021. Costs and quality-adjusted prosthesis year (QAPY) values were computed over a 20-year period in the study using the Markov model. The computed values were discounted by 5%. The results are presented as the incremental cost-effectiveness ratio. To assess the impact of uncertainty on cost-effectiveness analyses, a tornado diagram and Monte Carlo simulations were created.

RESULTS

Throughout the 20-year time horizon, tooth-supported fixed dental prostheses cost $985.58 cumulatively, whereas implant-supported single crown cost $2161.64 (US $1 = 9.22 ₺ as of 15 October 2021). The calculated incremental cost-effectiveness ratio is 1.333 per QAPY. Compared with the implant-supported single crown tooth-supported fixed dental prostheses, it offers a QAPY of 0.882 over a 20-year period, while costing an additional $1176.06.

CONCLUSIONS

These results suggest that the implant-supported single crown provided higher QAPY value but was costlier. When the research's findings are compared with the literature, it becomes clear that Türkiye has lower dental care expenses than most other nations.

Comparison of Stress and Strain Distribution Patterns in Canine Implant and Maxillary Bone in Three Occlusal Schemes Using Finite Element Analysis

OBJECTIVES

 This study aimed to compare the pattern of stress and strain distribution in canine implant and maxillary bone in the anterior group function (AGF), posterior group function (PGF), and canine guidance (CG) occlusal schemes by finite element analysis (FEA).

MATERIAL AND METHODS

 In this in vitro experimental study, a dental implant (10 × 4.1 mm) was inserted at the site of the maxillary canine in a model of the maxilla in Mimics software. The implant was scanned three-dimensionally and the data were transferred to SolidWorks software. The von Mises stress, shear stress, deformation, and strain were calculated in the AGF, PGF, and CG occlusal schemes by FEA.

STATISTICAL ANALYSIS

 Data were analyzed by ABAQUS software to calculate the stress transferred to the canine implant and maxillary bone in the three occlusal schemes.

RESULTS

 The maximum and minimum von Mises stress, elastic strain, shear stress, and deformation were noted in the AGF and PGF occlusal schemes, respectively, in all teeth.

CONCLUSION

 The PGF showed minimum von Mises stress, elastic strain, shear stress, and deformation in the canine implant and maxillary bone. Thus, it appears than the PGF is the best occlusal scheme for maxillary canine implant followed by the CG scheme.

Influence of Crown Height and Width on Marginal Bone Loss and Long-Term Stability of Dental Implants: A Systematic Review

Still, a major focus of research in implantology is how crown height and width affect marginal bone loss (MBL) and the long-term durability of dental implants. Maximizing the success of implants and lowering problems depends on an awareness of these elements. Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, this systematic review searched pertinent studies across several databases using keywords unique to databases. Studies on MBL and long-term implant stability evaluated in the review included those on crown height and width, horizontal and vertical cantilevers, and prosthesis dimensions. In the chosen studies, we found that both implant success and crestal bone loss were greatly influenced by crown height and width. Particularly in the posterior sections, horizontal cantilevers were connected to both increasing MBL and mechanical problems. Vertical cantilevers also affected MBL; however, their impacts were more obvious in circumstances with greater crown heights. Greater prosthesis widths, especially in the mandibular molar area, were linked to higher MBL. Bone density and insertion torque (IT) were the main determinants of MBL, more than the primary implant stability quotient. Early MBL was influenced by abutment height, mucosal thickness, and implant insertion depth; bone levels stabilized six months later. Short implants allow single crowns to be supported, but in some cases, a higher failure rate was seen. The success and stability of dental implants were found to be mostly dependent on crown height, width, and cantilever design. MBL and long-term stability are greatly influenced by horizontal and vertical cantilevers, which calls for careful design and planning. With specific care for bone density, IT, and early MBL stabilization, both short and standard implants can produce equivalent results. These results highlight the need for customized treatment plans to maximize implant success and lifetime.

Effect of different impression coping and scan body designs on the accuracy of conventional versus digital implant impressions: An in vitro study

OBJECTIVES

This in vitro study compared the accuracy of conventional versus digital impression techniques for angulated and straight implants using two different impression coping and scan body designs.

METHODS

Two implant systems were used: Straumann and Dentegris. Two implants were placed for each system, straight and angulated at 15 degrees mesiodistally. Conventional impressions were made using the splinted open-tray technique using narrow impression coping (NIC) and wide impression coping (WIC). The stone casts produced from the conventional impression were digitized with a lab scanner (3Shape D2000). Digital impressions were made using four intraoral scanners (IOS): 3Shape Trios 3, Medit i700, Cerec Omnicam, and Emerald Planmeca using short scanbodies (SSB) and long scanbodies (LSB). The scanning was repeated ten times to generate the Standard Tessellation Language (STL) files. The distance and angle deviations between impression copings and scanbodies were measured in reference to the master model.

RESULTS

The trueness and precision of SSB and WIC were significantly better than LSB and NIC (p<0.001). The range trueness of the platform deviation was better with SSB (37.1 to 51.9) than LSB (89.6 to 127.9 μm) and for WIC than NIC in conventional impressions (58.2 and 75.1 μm, respectively). The trueness of the angle deviation of digital scans with SSB (0.11 to 0.25 degrees) was significantly better than scans with LSB (0.31 to 0.57 degrees) and for WIC than NIC (0.21 and 0.52 degrees, respectively). The precision of the platform deviation of digital scans with SSB (12.4 to 34.5 μm) was higher than other scans and conventional impressions (42.9 to 71.4 μm). The precision of the angle deviation of Medit i700 and Trios 3 with SSB (0.17 and 0.20 degrees, respectively) was higher than other scans with SSB and conventional impressions (0.54 to 1.63 degrees).

CONCLUSIONS

Digital scans with SSB were more accurate than conventional splinted open-tray impressions. The type of impression coping and scanbody significantly affected the impression accuracy.

CLINICAL SIGNIFICANCE

The use of a short scanbody can increase the accuracy of digital impressions, and wide impression coping can increase the accuracy of conventional impressions, resulting in improved clinical outcomes.

Maintenance protocols for implant-supported dental prostheses: A scoping review

STATEMENT OF THE PROBLEM

Biological complications of implant-supported prostheses remain a concern. Therefore, standardizing hygiene protocols to promote their maintenance is important.

PURPOSE

The purpose of this scoping review was to identify available hygiene guidance for home care procedures, as well as periodicity and protocols for the professional maintenance of implant-supported prostheses.

MATERIAL AND METHODS

This study was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the study protocol was made available at: https://osf.io/5jdeh/. The search was last performed in the PubMed database on March 15, 2022 and was undertaken by 2 independent researchers. Clinical studies and reviews that evaluated home care and maintenance protocols for dental implant-supported prostheses (fixed or removable), without language restriction or year of publication, were included. A descriptive analysis was performed considering study characteristics (study design, restorative assembly, maintenance strategies, eligibility criteria, number of included studies, quality/level of evidence, and main findings).

RESULTS

The initial search yielded 3138 studies, of which 18 were included for descriptive analysis (6 critical reviews, 4 clinical trials, 3 systematic reviews, 2 guideline reports, 2 retrospective studies, and 1 transversal study). The main instrument recommended for home care was the use of a conventional toothbrush associated with triclosan-containing toothpaste in addition to interproximal aids (brushes or floss) for all types of restorations. The use of irrigation instruments was also frequently considered. For professional maintenance, almost all studies reported a positive effect of regular recalls every 3 months during the first year, followed by less regular recalls according to the motivation of the patient and home care efficacy. At each recall, the professional should evaluate the patient history, oral tissues, implant, abutments, and restorations, as well as perform professional cleaning of the prostheses with appropriate instruments so that the implants and abutments may be preserved.

CONCLUSIONS

Establishing an adequate hygiene protocol is indispensable for implant-supported restorations. To do so, the professional must guide and support the patient's home care by taking into account the patient's motivation and efficacy during the hygiene procedures. Also, for professional maintenance, the periodicity of recalls should be constant and include an evaluation of the condition of the restoration and adjacent tissues, followed by professional cleaning of prostheses, implants, and abutments, in addition to new instructions to improve patient home care.

Effect of scan body designs and internal conical angles on the 3-dimensional accuracy of implant digital scans

STATEMENT OF PROBLEM

Axial displacement is inevitable when connecting scan bodies to implants for digital scans using intraoral scanners, and axial displacement may reduce implant position accuracy in digital casts. However, studies assessing scan body type and accuracy are lacking.

PURPOSE

The purpose of this in vitro study was to assess the linear and angular displacements of implants in digital casts using 2 scan body types with or without a vertical stop to minimize the axial displacement and 2 internal conical connection implants (ICCIs) with different internal conical angles.

MATERIAL AND METHODS

Two identical reference casts were fabricated from epoxy resin by duplicating a partially edentulous mandibular dentiform. Each cast received 3 implants in the left first premolar, first molar, and second molar regions. One cast received an ICCI with a 7-degree internal conical angle (7-degree ICCI), and the other received an ICCI with an 11-degree internal conical angle (11-degree ICCI). A 10-mm polyetheretherketone (PEEK) cube was attached to the buccal area of the mandibular second premolar of each reference cast. A vertical stop was used in the experimental scan bodies to minimize the axial displacement, and conventional scan bodies were hand tightened to the implants in the reference casts. An intraoral scanner was used to fabricate 4 digital cast groups (2 implant types and 2 scan body types; each group had 10 casts). A coordinate measuring machine and digital inspection software program were used to measure the implant platform centroids (x, y, z) and projection angles (θXY, θYZ, θZX) of implant long axes in the reference and digital casts, respectively. One-way analysis of variance (ANOVA) and linear mixed model both with Tukey post hoc and 2-way ANOVA tests were performed to assess the significance of linear and angular displacements between groups (α=.05).

RESULTS

Significant differences were noted in all linear displacement variables among the 4 digital cast groups, except for Δx in the left first premolar implant. For the 7-degree ICCI, the linear displacement was statistically similar in the experimental and conventional scan bodies. However, for the 11-degree ICCIs, the experimental scan body group resulted in significantly smaller Δy, Δz, and Δd (Δd2=Δx2+Δy2+Δz2) than the conventional scan body group (P<.05). Overall, the 11-degree ICCIs demonstrated a significantly greater linear displacement than the 7-degree ICCI, regardless of the scan body type (P<.05). Significant differences between the test groups were observed for 10 of the 12 angular displacement variables (P<.05).

CONCLUSIONS

The 11-degree ICCIs demonstrated significantly greater linear displacements in Δy, Δz, and Δr than the 7-degree ICCIs. The experimental scan bodies with a vertical stop demonstrated significantly smaller linear displacements in the 11-degree ICCIs.

Tooth- and implant-related prognostic factors in treatment planning

Following a comprehensive patient examination, including the assessment of periodontal and peri-implant diseases as well as considering the patient's needs, a pretherapeutic prognosis for each tooth and implant is given. Teeth and implants with a secure pretherapeutic prognosis require simple procedures and may be regarded as secure abutments for function and with a doubtful pretherapeutic prognosis usually need a comprehensive therapy. Such teeth and implants must be brought into the category with a secure prognosis by means of additional therapy such as endodontic, restorative, and surgical procedures. Teeth and implants with a hopeless pretherapeutic prognosis should be extracted/explanted during the initial phase of cause-related therapy (i.e., infection control). For example, teeth with vertical root fracture or unrestorable caries and implants with mobility or unrestorable malposition fall into the category of hopeless units. The primary goal of periodontal and peri-implant therapy should be to arrest disease progression. The latest consensus statement highlights that periodontitis can be successfully controlled and treated teeth can be retained for life. Nevertheless, for patients with uncontrolled contributing factors, the endpoints might not always be achievable, and low disease activity may be an acceptable therapeutic goal. Similarly, the management of peri-implantitis frequently requires surgical intervention following nonsurgical therapy due to incomplete treatment outcomes. Different surgical modalities can be effective and lead to significant improvement; however, achieving complete resolution of peri-implantitis is challenging, not always predictable, and can depend on multiple baseline factors. Therefore, this review aims at summarising available evidence on the rationale for incorporating systemic, lifestyle-related, clinical, and radiographic prognostic factors into treatment planning of patients diagnosed with periodontal and peri-implant diseases.

Rehabilitation of mandibular resected patients using fixed immediately loaded corticobasal implant -supported prostheses. A case series

INTRODUCTION AND IMPORTANCE

Aliments such as congenital conditions, pathological, and iatrogenic circumstances may result in mandibular defects that can severely disturb the patients' oral health, functions (mastication, speech), aesthetics, and quality of life and present a rehabilitating challenge.

CASE PRESENTATION

we present a multidisciplinary treatment approach for three cases presented with mandibular resection as a consequence of cystic, benign, and malignant tumour eradication that were rehabilitated with immediately loaded fixed corticobasal implant-supported prostheses and a follow-up period of 5,5 and 4 years. The reported cases present with excellent implant survival, along with healthy peri-implant tissues, stable prostheses, enhanced speech, chewing ability, aesthetics, superior patient satisfaction, and improved overall self-esteem.

CLINICAL DISCUSSION

A multidisciplinary oral and maxillofacial team is mandatory for the successful rehabilitation of patients with mandibular resection and to restore soft and hard tissue loss. The reported treatment modality offers the patient immediate fixed implant-supported prostheses omitting the need for a bone grafting procedure, with optimum peri-implant tissue health, excellent biomechanical and prosthetic results, and significant improvement in function and satisfaction.

CONCLUSION

Corticobasal fixed implant-supported prostheses can be a reliable treatment modality for mandibular resection, resulting in notable enhancements in the patients' oral health, appearance, mastication, speech, and self-esteem.

Clinical Performance of 170 Frictional Morse Taper Implants: 2 Years Follow-Up

This study evaluated the clinical survival rates of 170 Morse taper implants through clinical and mechanical parameters in different therapeutic approaches such as single crowns, fixed partial prostheses, and fixed full-arch prostheses. Patients referred to the Center on Education and Research on Dental Implants from May 2017 to July 2018 with the indication for dental implant therapy, aged >18 years, without periodontal disease, recent evidence of inflammatory activity or other oral disorders, current pregnancy, uncontrolled diabetes mellitus or heavy smoking habit were included in this study. After 12 weeks of healing since the implants were placed in the mandible and after 16 weeks following implants placed in the maxilla, patients returned to the Center for prosthetic rehabilitation. After implant therapy, all patients underwent periodical, clinical, and prosthetic examinations every 6 months. Prosthetic restorations involved 109 fixed reconstructions in function. Few prosthetic complications were reported (6.55%). Twenty implants were rehabilitated with cemented prostheses; from those, 1 crown suffered a loss in retention/decementation. Of the 148 implants rehabilitated with screwed-retained prostheses, 6.76% suffered prosthetic screw loosening. The cumulative implant survival rate was 98.2%. When peri-implant tissue health was evaluated, the keratinized mucosa band appeared related to peri-implant tissue stability. Thus, Morse taper implants represented a successful procedure for implant rehabilitation, with a high cumulative implant survival rate, low prevalence of biological and prosthetic complications, and good stability of peri-implant tissues over the assessed period.

Fracture Resistance of a Bone-Level Two-Piece Zirconia Oral Implant System-The Influence of Artificial Loading and Hydrothermal Aging

Preclinical and clinical research on two-piece zirconia implants are warranted. Therefore, we evaluated the in vitro fracture resistance of such a zirconia oral implant system. The present study comprised 32 two-piece zirconia implants and abutments attached to the implants using a titanium (n = 16) or a zirconia abutment screw (n = 16). Both groups were subdivided (n = 8): group T-0 comprised implants with a titanium abutment screw and no artificial loading; group T-HL was the titanium screw group exposed to hydro-thermomechanical loading in a chewing simulator; group Z-0 was the zirconia abutment screw group with no artificial loading; and group Z-HL comprised the zirconia screw group with hydro-thermomechanical loading. Groups T-HL and Z-HL were loaded with 98 N and aged in 85 °C hot water for 107 chewing cycles. All samples were loaded to fracture. Kruskal-Wallis tests were executed to assess the loading/bending moment group differences. The significance level was established at a probability of 0.05. During the artificial loading, there was a single occurrence of an implant fracture. The mean fracture resistances measured in a universal testing machine were 749 N for group T-0, 828 N for group Z-0, 652 N for group T-HL, and 826 N for group Z-HL. The corresponding bending moments were as follows: group T-0, 411 Ncm; group Z-0, 452 Ncm; group T-HL, 356 Ncm; and group Z-HL, 456 Ncm. There were no statistically significant differences found between the experimental groups. Therefore, the conclusion was that loading and aging did not diminish the fracture resistance of the evaluated implant system.

Comparison of Four Different Dental Implant Removal Techniques in Terms of the Weight and Volume of Bone Loss

PURPOSE

Several approaches have been suggested for implant removal. However, further research is necessary to review data regarding the amount of bone removed and the duration of removal time for different procedures. This study evaluates and compares various implant removal techniques.  Materials and methods: A polyurethane block was scanned to create an implant surgical guide. Afterward, implant-guided surgery was performed on 60 simulated bone blocks. The implants were then separated into four groups and removed utilizing the counter-torque ratchet, trephine drills, burs, and piezosurgery.

RESULTS

For the weight of bone loss, there were significant differences in the median between the counter-torque ratchet technique (CTRT) and trephine (p < 0.01), CTRT and bur (p < 0.01), trephine and piezo (p < 0.01), and bur and piezo (p = 0.04). All groups, except CTRT and the piezo group, demonstrated a statistically significant difference (p < 0.01) in the procedure durations. Regarding the volume of bone loss, a statistically significant difference (p < 0.01) was found between each group.  Conclusions: CTRT showed the least amount of bone loss. On the other hand, the trephine technique was demonstrated to be the fastest. It is essential to consider the limitations and risks when choosing the approach for implant removal.

Short and Extra Short Dental Implants in Osseous Microvascular Free Flaps: A Retrospective Case Series

There is limited information regarding implant and prosthetic survival after osseous microvascular free flap (OMFF). This case series aims to describe the placement of short and extra short implants in osseous microvascular free flaps to support prostheses, and present an up to 40-month retrospective follow-up. Short and extra short dental implants were placed in six fibula free flaps (FFF) and in two microvascular deep circumflex iliac artery (DCIA) flaps. In total, 27 short and extra short dental implants have been placed into two different types of free flaps. Kaplan-Meyer (K-M) survival analyses were performed to evaluate the survival and success outcomes of implants and prostheses. Out of the eight patients reconstructed with free flap, five were rehabilitated with prostheses, one patient has a temporary prosthesis, and two patients are in the process of prosthetic rehabilitation. Twenty-seven implants were followed up for up to 40 months, and K-M analyses showed 100% implant survival probability (95% confidence interval: 100%), while the implant success probability was 91.0% (95% confidence interval: 68.6-97.7%). Short and extra short dental implants placed in OMFF presented high survival and success rates in a retrospective case series after up to 40 months.