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The aim of the present work was to evaluate six commercially available abutment screws by characterising roughness parameters, microstructure and mechanical properties. Six abutment screws from each implant system, were used. The surface roughness parameters (S a , S q , S sk , S ku , S pk , S k and S vk) were identified by an optical interferometric profiler. Microstructural observations and crystallographic analysis were performed using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectroscopy (EDX) device for elemental analysis and an X-ray diffractometer (XRD), respectively. The Martens Hardness (HM), Indentation Modulus (E IT), elastic index (η IT) and Vickers hardness (HV) of all specimens were determined by instrumented indentation testing (IIT). The results were analyzed by one-way ANOVA and Tukey multiple-comparison tests (a=0.05). EDX and XRD showed the abutment screws to be mixed α- and β-phase titanium alloys. Microstructural analysis revealed a fine homogeneous microstructure without porosity, consisting of fine dispersoid rods of β-phase embedded in a continuous α-phase matrix. Statistically significant differences were found among the mechanical properies and surface roughness parameters apart from S q , S pk and S vk. The tested abutment screws showed significant differences in the probed properties, and, thus, differences in their clinical behaviour are anticipated. [ABSTRACT FROM AUTHOR]

The removable partial denture, despite new technologies and new materials, continues to play a significant role in clinical dental practice. The purpose of the following study was to evaluate the design of new retention devices in Kennedy class II scenarios. For the study of "lamellar" retentive devices, four prosthetists were chosen. According to inclusion and exclusion criteria, prosthetists selected 16 patients (8 women and 8 men) whose upper arches had to be rehabilitated using a removable partial prosthesis. The results showed that the parameters taken into consideration, such as satisfaction, stability, aesthetics, and retention, had an average score that was higher than 3.30 (range 1–4), with an average standard deviation of 0.6225 in the four parameters, indicative that the data were relatively homogeneous and coherent. In conclusion, we can state that the skeletonized prosthesis with lamellar retentions, designed for Kennedy class II scenarios, has shown high acceptance in selected patients. [ABSTRACT FROM AUTHOR]

This study aims to assess and compare the impact of Monolithic Zirconia (MZ) and In-Ceram Zirconia (ZP) superstructures on stress distribution within implants and D2/D4 bone densities under 200 N vertical and oblique occlusal loads using three-dimensional finite element analysis via ANSYS WORKBENCH R2. The analysis employed maximum and minimum von Mises stress values. Modeling an implant (4.2 mm diameter, 10 mm length) and abutment (0.47 mm diameter), with an 8 mm diameter and 6 mm length single crown, the research identified lower von Mises stresses in D2 cancellous bone with the MZ model under vertical loading. Conversely, under oblique loading, the ZP model exhibited maximum von Mises stresses in D4 bone around the implant. This underscores the critical need to consider physical and mechanical properties, beyond mere aesthetics, for sustained implant success. The findings highlight the effect of material composition and stress distribution, emphasizing the necessity of durable and effective implant treatments. [ABSTRACT FROM AUTHOR]

This article discusses the different types of abutment-implant connections in dental implants, specifically focusing on the butt-joint and Morse Taper connections. The quality of the connection between the abutment and implant is crucial in preventing bacterial infiltration and subsequent bone loss and soft tissue infection. The Morse Taper connection, which forms a tight cold weld, is effective in preventing bacterial ingrowth and creating a stable connection. In contrast, the butt-joint connection allows bacteria to enter the implant, leading to potential complications. The article emphasizes the importance of choosing the appropriate abutment-implant connection to ensure successful implant treatment. [Extracted from the article]

The aim of this study was to evaluate the mechanical behavior of UCLA and Mini-conical abutments for implants with Tri-channel connections regarding torque loss and vertical misfit. Twenty 3-element metal-ceramic fixed partial dentures (FPD) supported by 2 implants were manufactured and divided into 2 groups (n = 10): UCLA (group 1) and Mini-conical Abutments (group 2). The evaluation of torque loss was carried out before and after mechanical cycling, while the vertical fit was evaluated throughout the different stages of manufacturing the prostheses, as well pre- and postcycling (300,000 cycles, 30 N). Statistical analyses of torque loss and vertical misfit were performed using the linear mixed effects model. Both groups showed torque loss after mechanical cycling (P <.05); however, there was no significant percentage differences between them (P =.795). Before cycling, the groups showed a significant difference in terms of vertical misfit values (P <.05); however, this difference was no long observed after cycling (P =.894). Both groups showed torque loss after the cycling test, with no significant difference (P >.05). There was no significant difference in vertical misfit after mechanical cycling; however, in group 1 (UCLA) there was accommodation of the implant-UCLA abutment interface, while group 2 (Mini-conical abutment) did not show changes in the interface with the implant after the test. Both groups behaved similarly regarding the torque loss of the prosthesis retention screws pre- and postmechanical cycling, with greater loss after the test. [ABSTRACT FROM AUTHOR]

Silane chemistry has emerged as a powerful tool for surface modification, offering a versatile means to enhance the properties of various substrates, such as dental implant abutment materials. In this study, we investigated the stability of the 3‐aminopropyldiisopropylethoxysilane (APDS) layer on yttria‐partially stabilized zirconia (Y‐TZP) surfaces after mechanical, acid, and thermal treatment in order to simulate fluctuations within the oral cavity. To accomplish that, the viability of human gingival fibroblasts on APDS‐modified surfaces after applied treatment strategies was assessed by live/dead staining. Moreover, the hydrolysis stability and enzymatic degradation resistance of crosslinked fibronectin to the APDS layer was examined by immunostaining and western blot. The results revealed that the applied modifications were not affected by the different treatment conditions and could withstand the fluctuations in the oral cavity. Furthermore, crosslinked fibronectin on silanized Y‐TZP was stable against hydrolysis over 21 days and enzymatic degradation. We thus can conclude that the proposed functionalization method has high potential to tolerate harmful effects within the oral cavity and remains unchanged on the surface. [ABSTRACT FROM AUTHOR]

Background: Dental implants can cause complications, including the loosening of the abutment screw or fracture. However, there is no standardized technique for removing broken abutment screws. This necessitates further research. Objective: This study aimed to measure heat generation during screw removal to better understand its implications for dental implant procedures. Material and methods: The experimental setup involved using synthetic bone blocks and titanium implants. An ultrasonically operated instrument tip was utilized for screw removal. Infrared thermometry was employed for accurate temperature measurement, considering factors such as emissivity and distance. Statistical analysis using linear regression and ANOVA was conducted. Results: The findings revealed an initial rapid temperature increase during the removal process, followed by a gradual decrease. The regression model demonstrated a strong correlation between time and temperature, indicating the heat generation pattern. Conclusion: Heat generation during screw removal poses risks such as tissue damage and integration issues. Clinicians should minimize heat risks through an intermittent approach. The lack of a standardized technique requires further research and caution. Understanding the generated heat optimizes implant procedures. [ABSTRACT FROM AUTHOR]

Aim: The aim of this randomized, prospective, and clinical multicenter study was to compare the overall clinical performance of two restorative options over a 5‐year period: individualized CAD/CAM abutments veneered with a hand‐layered ceramic, and prefabricated zirconium dioxide abutments veneered with press ceramic and inserted into a single edentulous gap in the anterior maxilla. Materials and Methods: Forty subjects were recruited from two universities: 20 from the University of XX and 20 from the University of XY. Each subject received an implant to restore a single edentulous gap in the maxillary anterior region (14–24 FDI). 20 patients were randomized into each Group. Group A received a one‐piece single crown produced from a prefabricated zirconia abutment with pressed ceramic and Group B received an individualized CAD/CAM zirconia abutment with a hand‐layered technique. After 5 years, the aesthetic and radiographic parameters were assessed. Results: Group A had four dropouts and one failure, resulting in a 95% survival rate and 95% success rate. Group B had two dropouts and two failures which resulted in a 90% survival rate and 90% success rate. No crestal bone level changes were observed, with a mean DIB of 0.06 mm in Group A and 0.09 mm in Group B. No statistically significant differences were present at baseline, 6 months, 1 year, 3 years, or 5 years for DIB values between time points and groups. Pink aesthetic score/white aesthetic score, Peri‐Implant and Crown Index, and Implant Crown Aesthetic Index values were stable over time at all five points for both groups. Conclusion: Both implant‐supported restorative options represent a valuable treatment option for the restoration of implant crowns in the anterior maxilla. Clinical Significance: In general, the use of ceramic abutments in the anterior zone represents a valuable treatment procedure with both standardized and CAD/CAM individualized abutments and following the recommendations from the respective manufacturer(s). [ABSTRACT FROM AUTHOR]

Objective: To analyze the influence of restoration design (partial‐coverage restoration vs. crown) and ceramic layer thickness on the performance and failure loads of CAD/CAM‐fabricated lithium disilicate (LDS) reconstructions on molars after fatigue. Materials and Methods: Seventy‐two posterior monolithic CAD/CAM‐fabricated LDS restorations (IPS e.max CAD, Ivoclar Vivadent) with different occlusal/buccal ceramic layer thicknesses (1.5/0.8, 1.0/0.6, and 0.5/0.4 mm) and restoration designs (PCR: non‐retentive full‐veneer/partial‐coverage restoration, C: crown,) were investigated and divided into six groups (n = 12, test: PCR‐1.5, PCR‐1.0, PCR‐0.5; control: C‐1.5, C‐1.0, C‐0.5). LDS restorations were adhesively bonded (Variolink Esthetic DC, Ivoclar Vivadent) to dentin‐analogue composite dies (Z100, 3M ESPE). All specimens were subjected to thermomechanical loading (1.2 million cycles, 49 N, 1.6 Hz, 5–55°C) and exposed to single load to failure testing. Failure analysis was performed with light and scanning electron microscopies. Data were statistically analyzed using ANOVA, Tukey‐Test, and t‐test (p < 0.05). Results: Eight crown samples (C‐0.5) and one PCR specimen (PCR‐0.5) revealed cracks after fatigue, resulting in an overall success rate of 87.5% (crowns: 75%, PCRs: 96.88%). Direct comparisons of PCRs versus crowns for thicknesses of 0.5 mm (p < 0.001) and 1.0 mm (p = 0.004) were significant and in favor of PCRs. Minimally invasive PCRs (0.5 and 1.0 mm) outperformed crowns with the identical ceramic thickness. No difference was detected (p = 0.276) between thickness 1.5 mm PCRs and crowns. Conclusions: Minimally invasive monolithic CAD/CAM‐fabricated posterior LDS PCRs (0.5 and 1.0 mm) resulted in superior failure load values compared to minimally invasive crowns. Minimally invasive crowns (0.5 mm) are prone to cracks after fatigue. Clinical Significance: Minimally invasive CAD/CAM‐fabricated LDS PCR restorations with a non‐retentive preparation design should be considered over single crowns for molar rehabilitation. [ABSTRACT FROM AUTHOR]

Objective: A comprehensive classification of structurally compromised teeth (SCT) was introduced. Clinical Considerations: Dental injuries or operative mismanagement undermine the structural integrity of the tooth abutment, reducing its biomechanical strength and rendering restorative procedures challenging. To standardize the overall pre‐operative evaluations and determine the biological and mechanical features, a classification of the coronal and cervical tooth defects, as well as an attentive analysis of the most apical location of the residual cervical tooth structure along the whole perimeter and the most coronal location of the bucco/lingual residual structure was presented. Considering the residual cervical structure, five possible clinical scenarios were individuated with respect to the gingival margin, gingival sulcus, supracrestal tissue attachment and bone crest (BC). The latter prevents the isolation procedures rendering the adhesive restorations unfeasible. Instead, the location of the most apical portion of residual cervical structure within subgingival/intrasulcular depth (>1.5 mm above BC) can be considered restorable. Conclusions: This classification is threefold: to enclose all the possible clinically encountered tooth defects, to identify the apical problems of SCT to appropriately manage the perio‐restorative interfaces, and to evaluate the tooth resistance capacity of SCT, as to plan and perform the most adequate biomechanical restorative approach. Clinical Significance: The present classification is proposed to provide a complete perspective of structurally compromised teeth to standardize the biologic and biomechanical evaluations during planning of restorative procedures. [ABSTRACT FROM AUTHOR]

Introduction: The pulps of healthy teeth used as abutments for Fixed Partial Dentures (FPD) undergo mechanical and thermal stresses during tooth preparation. The remaining dentin thickness, the heat produced during tooth preparation, and the permeability of dentinal tubules influence the severity of pulpal injury. Prophylactic Root Canal Therapy (RCT) could be an option to provide better outcomes for FPD treatment. Aim: To assess dentists' perception regarding the need for prophylactic RCT of abutment teeth in FPD through a questionnaire. Materials and Methods: A Questionnaire based Cross-sectional Surve was conducted among 200 dental professionals in the Indian states of Kerala and Maharashtra over a period of two months. The participants included dental professionals from private clinics, dental Institutions, and postgraduate students in these states. The Chi-square test of proportion was performed to assess significant differences between each response. Results: Total 67 out of 200 practitioners, accounting for 33.5%, recommended prophylactic RCT, while 60 (30%) practitioners disagreed with it. A total of 152 (76%) practitioners suggested clinical assessment of abutment teeth before starting the tooth preparation. Total 70 (35%) practitioners had never experienced pulpal damage in abutment teeth in their clinical practice. In contrast, 127 (63.5%) practitioners experienced pulpal damage in less than half of the total cases, and 3 (1.5%) practitioners experienced failures like pulp necrosis or irreversible pulpitis in more than half of the total cases. Conclusion: Total 33.5% of the surveyed dental practitioners recommended prophylactic endodontic treatment for abutment teeth in FPDs. Implementing precise elective RCT guidelines into dental curricula was suggested as a potential avenue to enhance decision-making and improve patient outcomes by reducing the incidence of pulpal damage beneath FPDs. [ABSTRACT FROM AUTHOR]

Purpose: This clinical study aimed to evaluate the outcomes of resin-bonded attachments (RBAs) for precision-retained removable dental prostheses (RDPs) after at least two years of clinical maintenance. Methods: Since December 1998, 205 RBAs (44 bonded to posterior teeth, 161 to anterior teeth) have been inserted in 123 patients (62 females and 61 males; mean age, 63.6 ± 9.6 years) who were recalled annually. The abutment teeth underwent a minimally invasive preparation limited to the enamel. RBAs were cast in a cobalt-chromium alloy with a minimum thickness of 0.5 mm and adhesively luted with a luting composite resin (Panavia 21 Ex or Panavia V5, Kuraray, Japan). We evaluated caries activity, plaque index, periodontal condition, and tooth vitality. The Kaplan-Meier survival curves were used to account for the reasons for failure. Results: The mean observation time of RBAs until the last recall visit was 84.5 ± 51.3 months (range, 3.6-270.6). During the observation period, 33 RBAs debonded in 27 patients (16.1%). The 10-year success rate according to the Kaplan-Meier analysis was 58.4%, which dropped to 46.2% after 15 years of observation if debonding was considered a failure. If rebonded RBAs were regarded as surviving, the 10- and 15-year survival rates would be 68.3% and 61%, respectively. Conclusions: The use of RBAs for precision-retained RDPs appears to be a promising alternative to conventionally retained RDPs. As reported in the literature, the survival rate and frequency of complications were comparable with those of conventional crown-retained attachments for RDPs. [ABSTRACT FROM AUTHOR]

Purpose: To investigate survival rates and technical and biological complications of one-piece screw-retained hybrid abutments in implant-supported single crowns (SCs). Study selection: An electronic search was performed on five databases for clinical studies involving implant-supported single hybrid abutment crowns constructed using titanium-base (Ti base) abutments, with at least 12 months of follow-up. The RoB 2, Robins-I, and JBI tools were used to assess the risk of bias for the different study types. Success, survival, and complication rates were calculated, and a meta-analysis was performed to obtain a pooled estimate. Peri-implant health parameters were extracted and analyzed. Results: 22 records (20 studies) were included in this analysis. Direct comparisons between screw-retained hybrid abutment SCs and cemented SCs showed no significant differences in the 1-year survival and success rates. For SCs using a hybrid abutment crown design, their 1-year survival rate was 100% (95% CI: 100%-100%, I2 = 0.0%, P = 0.984), and a success rate of 99% (95% CI: 97%-100%, I2 = 50.3%, P = 0.023) was calculated. No confounding variables significantly affected the estimates. The individual technical complication rate was low at 1-year follow-up. The estimated incidence of all types of complications in hybrid abutment SCs is less than 1%. Conclusions: Within the limitations of this study, implant-supported SCs using a hybrid abutment crown design showed favorable short-term clinical outcomes. Additional well-designed clinical trials with at least a 5-year observation period are required to confirm their long-term clinical performance. [ABSTRACT FROM AUTHOR]

Purpose: This systematic review aimed to evaluate the effects of implant placement sites on the biomechanical behavior of implant-assisted removable partial dentures (IARPDs) using finite element analysis (FEA). Study selection: Two reviewers independently conducted manual searches of the PubMed, Scopus, and ProQuest databases for articles investigating implant location in IARPDs using FEA, according to the 2020 Systematic Reviews and Meta-analyses statement. Studies published in English up to August 1, 2022, were included in the analysis based on the critical question. Results: Seven articles meeting the inclusion criteria were systematically reviewed. Six studies investigated mandibular Kennedy Class I and one study investigated mandibular Kennedy Class II. Implant placement reduced the displacement and stress distribution of the IARPD components, including dental implants and abutment teeth, regardless of the Kennedy Class type and dental implant placement site. Most of the included studies showed that, based on the biomechanical behavior, the molar region, rather than the premolar region, is the preferred implant placement site. None of the selected studies investigated the maxillary Kennedy Class I and II. Conclusions: Based on the FEA regarding mandibular IARPDs, we concluded that implant placement in both the premolar and molar regions improves the biomechanical behaviors of IARPD components, regardless of the Kennedy Class. Implant placement in the molar region results in more suitable biomechanical behaviors compared with implant placement in the premolar region in Kennedy Class I. No conclusion was reached for Kennedy Class II due to the lack of relevant studies. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Computerized Dentistry is the property of Quintessence Publishing Company Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article discusses the relevance of dental torque wrenches in implant dentistry and the potential influence of their use. The accuracy of measurements made by dental torque wrenches and their possible complications are explored. The article highlights the importance of using appropriate techniques and instruments for successful implant procedures. It also discusses the different methods of recording the reference scale of dental torque wrenches and the challenges that arise when the scale becomes unreadable. The authors emphasize the need for proper care and maintenance of precision instruments and suggest that the industry should develop products with extended useful life and maintained precision. [Extracted from the article]

Copyright of Quintessenz der Zahntechnik is the property of Quintessenz Verlags GmbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: The purpose of this study was to evaluate the difference in marginal bone level, technical and biological complications between screw-retained and cemented all-ceramic implant-supported crowns fabricated on zirconia abutment at different follow-up periods. Materials and Methods: Independent search was conducted in Cochrane Library, EBSCO, and PubMed/ PubMed Central/MEDLINE databases and the Google Scholar search engine for prospective studies and randomized controlled trials published between January 2014 and June 2023 evaluating the marginal bone level, technical and biological complications between screw-retained and cemented all-ceramic implant-supported crowns fabricated on zirconia abutment. Meta-analysis was conducted to assess the quantitative data on the marginal bone level and biological complications. Results: A total of eight studies were included for qualitative synthesis and six studies for quantitative synthesis. For marginal bone level, no statistically significant difference was observed (P = 0.83 and P = 0.69, respectively) during the follow-up period of 3 years and 5 years. For probing depth, the cemented group showed more amount of probing depth than the screw-retained group at a follow-up period of 3 years (P < 0.05) whereas no statistically significant difference was observed at a follow-up period of 5 years (P = 0.73). For bleeding on probing, the cemented group showed more probing depth than the screw-retained group at a follow-up period of 5 years (P = 0.10). Conclusion: The evidence suggests that the screw-retained group showed no statistically significant difference in marginal bone level, comparatively fewer biological complications, and relatively higher technical complications than the cemented group at different follow-up periods. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to assess the effectiveness and practicality of erbium lasers in the removal of ceramic restorations and appliances from natural teeth and dental implant abutments in clinical practice. Methods: A retrospective analysis was conducted, involving 29 clinical cases with a total of 52 abutments requiring the removal of various ceramic restorations. The analysis evaluated the clinical procedures performed, including the type and material of the prosthetic, the type of cement used, laser setting parameters, retrieval time, and retrieval success. Results: Out of the 52 abutments, 50 were successfully retrieved without causing any damage (>95%) using either an Er,Cr:YSGG laser (N = 6) or an Er:YAG laser (N = 46). In one case, a crown was partially sectioned to prevent any negative impact of laser irradiation on the adhesive strength between the post and tooth, and in another case, a fracture occurred during debonding. The restorations consisted of 13 lithium disilicate and 39 zirconia units, including six veneers, 38 single crowns, and three fixed partial dentures (FPDs). The retrieval time varied depending on the restoration type, material thickness, cement type, retention form/fitting of the abutment and restoration, ranging from 2.25 ±0.61 minutes for veneers, 6.89 ±8.07 minutes for crowns, to 25 ±10 minutes per abutment for FPDs. Removal of a zirconia crown required more time, 7.12±8.91 minutes, compared to a lithium disilicate crown, 5.86 ±2.41 minutes. The debonding time was influenced by the laser settings as well as materials and types of prosthesis. Conclusions: Erbium lasers present a safe and effective alternative to invasive methods for removing ceramic restorations, without causing harm to the abutment or prosthesis. Laser-assisted debonding allows for recementation of the restorations during the same appointment, making it a conservative and viable option for ceramic crown retrieval in clinical settings. [ABSTRACT FROM AUTHOR]

Background: In-vitro data from a clinically well-known lithium disilicate ceramic reference was used to assess the expected performance of resin-based materials in implant dentistry. The purpose of the study was to compare the bond strength and marginal adaptation of nano-ceramic hybrid composite crowns cemented to stock cement-retained abutments to lithium disilicate crowns. Methods: Twenty abutment analogs were embedded into auto-polymerizing acrylic resin blocks. The blocks were divided into 2 groups according to the restorative crown material. The 2 groups were divided as follows: Resin nano-ceramic group and lithium disilicate group. Abutment analogs in both groups were scanned using a laboratory scanner, and the restorations were designed, manufactured, and cemented with resin cement over the corresponding group. All samples were tested for marginal adaptation and bond strength after storage for 24 hours at 37 °C in 100% humidity. Data were collected, tabulated, and statistically analysed using the appropriate tests. Normality was checked using Shapiro Wilk test and Q-Q plots. Data were normally distributed. Variables were presented using mean, 95% Confidence Interval (CI) and standard deviation in addition to median and Inter Quartile Range (IQR). Differences between groups regarding debonding forces was assessed using independent t test. Two Way ANOVA was performed to assess the effect of material and bonding on marginal gap. All tests were two tailed and p value was set at < 0.05. Results: Marginal gap and debonding force values were significantly different according to the type of material used (P <.05). Resin nano-ceramic crowns presented lower marginal gap values before (20.80 ± 8.87 μm) and after (52.11 ± 22.92 μm) bonding than lithium disilicate crowns. The debonding force value for resin nano-ceramic crowns (284.30 ± 26.44 N) was significantly higher than that for lithium disilicate crowns (253.30 ± 33.26 N). Adhesive failure mode was detected in all the specimens in both groups. Conclusions: The type of material used for implant-supported cement-retained crowns had a statistically significant effect on marginal adaptation and bond strength. Resin nano-ceramic implant-supported cement-retained crowns had better marginal adaptation and higher bond strength than those manufactured using lithium disilicate. [ABSTRACT FROM AUTHOR]

Objectives: To compare the clinical, radiographic, and immunological outcomes between one‐piece versus two‐piece zirconia abutments supported single implant crowns in the esthetic region. Materials and Methods: The study followed a split‐mouth, double‐blind, and randomized controlled clinical design for a duration of 3 years. Twenty‐two eligible patients with 44 implants were randomly assigned to two groups: Group 1 (one‐piece zirconia abutment with zirconia base, n = 22) and Group 2 (two‐piece zirconia abutment with titanium base, n = 22). The primary outcome was the technical complication rate. Additionally, survival rates, cytokines concentrations in peri‐implant crevicular fluid (PICF), peri‐implant conditions, marginal bone loss, and pink/white esthetics score (PES/WES) were assessed as secondary outcomes. Results: Twelve of 22 patients attended the 1‐year follow‐up (due to the COVID pandemic), and 19 patients attended the 3‐year examination. Two abutments in Group 1 were fractured after 10 and 12 months in function. Additionally, one screw loosening occurred in Group 1 at 1‐year follow‐up. The 3‐year technical complication rate was significantly higher in Group 1 than that in Group 2 (15.79% vs. 0%, p <.001). The 3‐year implant survival rate was 100% in both groups. The concentration of IFN‐γ in PICF was significantly upregulated in Group 2 (p =.018). Furthermore, the IL‐6 concentration was positively correlated with BOP% (p =.020). Conclusions: Two‐piece zirconia abutments exhibited superior technical performance compared to one‐piece designs during a 3‐year follow‐up in the anterior region. However, further long‐term research is necessary to verify the immunological stability of two‐piece zirconia abutments. [ABSTRACT FROM AUTHOR]

Objective: To develop a comprehensive decision‐making tree for evaluating mid‐facial peri‐implant soft tissue dehiscence in the esthetic zone and provide a systematic approach for assessing various clinical case scenarios, determining appropriate treatment strategies, and considering factors such as the need for soft tissue augmentation, prosthetic changes, or implant removal. Clinical Considerations: This clinical decision tree illustrates numerous case scenarios with various esthetic complications around an esthetically compromised, but clinically healthy single implant and provides clinicians with possible solutions as a predictable map for horizontal and vertical soft tissue augmentation in order to manage different clinical circumstances. According to current evidence, the key to treating such esthetic complications is the use of an adequate pre‐surgical prosthetic interdisciplinary approach with proper surgical techniques in order to optimize soft tissue dimensions and create better esthetic results. This may be accomplished through a purely surgical, combination of surgical and prosthetic, or purely prosthetic approaches. Conclusions: The present report describes a series of successfully treated peri‐implant esthetic complication cases in accordance with the decision‐making tree that the authors recommend in order to achieve better long‐term esthetic outcomes. Clinical Significance: The combination of adequate pre‐surgical prosthetic interdisciplinary collaboration and proper surgical technique is critical in the optimization of sufficient soft tissue dimensions and contributes to a more highly esthetic result. This study demonstrates a clinical decision‐making tree to provide comprehensive, effective therapy of an esthetically compromised dental implant by using one of the following approaches: purely prosthetic, purely surgical, or a combination of surgical and prosthetic with or without abutment removal. [ABSTRACT FROM AUTHOR]

Objective: This 1-year prospective clinical trial was designed to assess the microbial, clinical, radiographic, and prosthetic parameters after disinfection of the implant abutment connection using Er,Cr:YSGG (erbium, chromiumdoped: yttrium, scandium, gallium, and garnet) and Nd:YAG (neodymium-doped yttrium, aluminum, garnet). Materials and methods: All the patients were divided into four groups; Group I: Nd:YAG laser, Group II: Er,Cr:YSGG laser, Group III: 0.2% chlorhexidine (CHx), and Group IV: steam disinfection. Peri-implant parameters assessed included peri-implant bleeding scores (PIBS), peri-implant plaque scores (PIPS), periimplant pocket depth (PIPD), and crestal bone loss (CBL). The peri-implant plaque samples were acquired to perform microbiological analysis to assess Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia, respectively. All measurements were completed at baseline, 6 months, and 12 months postsurgery. Multiple groups were compared with the help of the Bonferroni post-hoc adjustment test (p < 0.01). Logistic regression models were utilized to assess the association between age, oral hygiene practices (brushing and flossing), and duration of implant function. Results: At the baseline level, there were no discernible differences in the peri-implant parameters between the study groups (p > 0.05). At the 6-month (p < 0.01) and 12-month (p < 0.001) follow-ups, all four study groups demonstrated a significant improvement in PIPS and PIBS, with no significant differences between the groups at baseline (p > 0.05). Based on an intergroup comparison, Group I (Nd:YAG) showed a significant decrease in PIBS when compared with the other groups. Group II showed a considerable decrease in PIPD and enhancements in CBL when compared with Groups I, III, and IV (p < 0.01). At the 6- and 12-month follow-up periods, P. gingivalis and T. denticola reduction were found to be statistically higher in Group II, whereas P. gingivalis and T. forsythia mean log CFU/mL were found to be statistically higher in Group I. Conclusions: Nd:YAG and Er,Cr:YSGG lasers both outperformed CHx and steam disinfection in terms of clinical, peri-implant, and prosthetic results when used to clean implant abutments. [ABSTRACT FROM AUTHOR]

High translucent zirconia (HTZ) has excellent mechanical properties, biocompatibility, and good semitranslucency making it an ideal material for aesthetic anterior dental implant abutments without antibacterial properties. In the oral environment, the surface of the abutment material is susceptible to microbial adhesion and biofilm formation, which can lead to infection or peri-implantitis and even implant failure. This study aims to promote the formation of a biological seal at the implant-soft tissue interface by modifying the HTZ surface, using the load-bearing capacity of the aluminosilicate porous structure and the broad-spectrum antibacterial effect of silver nanoparticles to prevent peri-implant bacterial infection and inflammation and to improve the success rate and prolong the use of the implant. FE-SEM (field emission scanning electron microscopes), EDS (energy dispersive spectroscopy), and XPS (X-ray photoelectron spectroscopy) results showed that aluminosilicate non-vacuum sintering can form open micro- and nanoporous structures on HTZ surfaces, and that porous aluminosilicate coatings obtain a larger number, smaller size, and more uniformly shaped silver nanoparticles than smooth aluminosilicate coatings, and could be deposited deeper in the coating. The ICP-AES (inductively coupled plasma-atomic emission spectroscopy) results showed that the early silver ion release of both the smooth silver coating and the porous silver coating was obvious, the silver ion concentration released by the former was higher than that of the latter. However, the silver ion concentration released by the porous silver coating was higher than that of the smooth coating when the release slowed down. Both smooth and porous silver coatings both inhibited E. coli (Escherichia coli), S. aureus (Staphylococcus aureus), and L. acidophilus (L. acidophilus), and porous silver coatings had stronger antibacterial properties. The silver coating was successfully constructed on the surface of HTZ, through aluminium silicate sintering and silver nitrate solution impregnation. It was found that the high concentration environment of silver nitrate solution was more advantageous for nano-Ag deposition, and the non-vacuum sintered porous surface was able to obtain a larger number of nano-Ag particles with smaller sizes. The porous Ag coating exhibited superior antibacterial properties. It was suggested that the HTZ with silver coating had clinical application, and good antibacterial properties that can improve the survival rate and service life of implants. [ABSTRACT FROM AUTHOR]

This case report focuses on applying a protocol for dental implant restoration in aesthetic zones, specifically the anterior sectors. The protocol aims to achieve optimal results with minimal complexity, reducing the number of sessions and impressions required for transferring clinical information to the laboratory. The historical development of dental implantology and the evolution of dental implant restoration workflows are discussed, highlighting the significance of osseointegration and advancements in materials, surgical techniques, and prosthetic components. The case report describes rehabilitating congenitally missing lateral incisors using fibre-reinforced composite Maryland bridges for provisional restoration and Osstem TSIII (Osstem®, Seoul, South Korea) implants, zirconia abutments, and disilicate lithium crowns for definitive repair. The discussion covers essential aspects of aesthetic dental implant restoration, including materials, types of dental implants, surgical techniques for soft tissue enhancement, and prosthetic and impression techniques. The study emphasises the importance of selecting appropriate materials, employing advanced surgical procedures, and utilising accurate prosthetic and impression techniques to enhance the aesthetic outcomes of dental implant restorations. A multidisciplinary approach and patient-centred care are essential for successful aesthetic dental implant restorations. The methodology presented in this manuscript demonstrates its effectiveness in achieving optimal outcomes while minimising stress on soft tissues and improving patient comfort and satisfaction. This case report contributes to dental implant restoration, providing evidence-based techniques for achieving aesthetic and functional success. [ABSTRACT FROM AUTHOR]

(1) Background: This systematic review intends to answer the following Patient–Intervention–Comparison–Outcome (PICO) question: Do digital impression systems generate significant errors during scanning in extensive implant restorative treatments? (2) Methods: Following the PRISMA protocol and according to predefined inclusion criteria, two trained investigators searched for relevant articles in the PubMed database and related sources using a standard keyword sequence. The investigators were responsible for selecting studies and performing quality analysis. (3) Results: From 78 titles, only 9 studies were selected. An analysis of registration distortion variations was conducted for each potential influencing factor in terms of accuracy: interimplant distance, implant angulation, scanner type, and scanning body type. The results showed repeatable differences in accuracy between types of scanning technologies and techniques, and a positive correlation between interimplant distance and the amplitude of deviations detected in comparative analysis, with the highest error levels in total edentulous arch recording. There was no consensus on the error level owing to implant angulation, and statistically significant differences were found between the types of scan bodies used. (4) Conclusions: Digital impression systems generate significant errors during scanning in extensive implant restorative treatments, influenced by scanning technology, interimplant distance, and scanning body type. [ABSTRACT FROM AUTHOR]

This document provides an overview of various techniques for implant exposure and placement in dental surgery. It explains the mid-crestal incision technique, which involves making an incision slightly palatal/lingual to the crest and elevating a full-thickness flap. Another technique discussed is the U-shape exposure with a roll-in flap. The document also highlights the importance of grafting new tissue into the implant site, including the use of vascularized inter-positional periosteal connective tissue (VIP-CT) flap and connective tissue grafts. It emphasizes the need for preoperative planning, postgraduate training, and specific surgical instruments for these procedures. [Extracted from the article]

This study aimed to investigate the effect of four retention systems for implant-supported posterior crowns under compressive loading using three-dimensional finite element analysis. A morse-taper dental implant (4.1 × 10 mm) was designed with Computer Aided Design software based on non-uniform rational B-spline surfaces. According to International Organization for Standardization 14,801:2016, the implant was positioned at 3 mm above the crestal level. Then four models were designed with different crown retention systems: screw-retained (A), cement-retained (B), lateral-screw-retained (C), and modified lateral-screw-retained (D). The models were imported to the analysis software and mesh was generated based on the coincident nodes between the juxtaposed lines. For the boundary conditions, two loads (600 N) were applied (axial to the implant fixture and oblique at 30°) totaling 8 conditions according to retention design and loading. The von-Mises stress analysis showed that different retention systems modify the stress magnitude in the implant-supported posterior crown. There is a similar stress pattern in the implant threads. However, models C and D presented higher stress concentrations in the crown margin in comparison with A and B. The oblique loading highly increased the stress magnitude for all models. In the simulated conditions, part of the stress was concentrated at the lateral screw under axial loading for model C and oblique loading for model D. The results indicate a possible new failure origin for crown retained using lateral screws in comparison to conventional cement-retained or screw-retained systems.

Purpose: To conduct a systematic review to evaluate the influences of material and surface used for dental implant abutments on the proliferation of human gingival fibroblasts. Materials and Methods: The focus question of this review was: Which material/surface characteristics used for dental implant abutments influence/enhance the proliferation of human gingival fibroblasts? The Medline/PubMed, Embase, and Cochrane Library databases were searched using "gingiva," "fibroblasts," "proliferation," and "dental implant abutments" as main keywords, with AND/OR as Boolean operators. In vitro studies reporting 3 to 4 or 6 to 7 days of cell proliferation, surface hydrophilicity, and surface roughness were included. A quality assessment of the selected studies was performed using the web-based Science in Risk Assessment and Policy (SciRAP) tool. Results: The search identified 1,144 studies, and 44 were eligible for inclusion. The average reporting quality SciRAP score was 82.87 ± 10.68, and the average methodologic quality SciRAP score was 87.35 ± 10.55. Machined, polished, and coated titanium and zirconia surfaces were most commonly investigated. Several studies analyzed aluminum oxide, cobalt-chromium-molybdenum alloy, lithium disilicate, polyetheretherketone, polymer-infiltrated ceramic network, and bioglass. The best cell proliferation was observed on zirconia and on titanium harboring nanotubules or microgrooves. Ultraviolet light treatment, polydopamine, and nitride coatings also improved cell proliferation. Due to the heterogeneity of the data, no correlation could be established between cell profileration and surface hydrophilicity or roughness. However, surface roughness in the range of Ra = 15 to 145 nm and Sa = 19 to 500 nm on titanium and zirconia proved most suitable. Conclusion: Titanium surfaces with directional guidance patterning and zirconia surfaces best supported cell proliferation during the first week of cell culture. Lack of standardization in surface definitions (machined or polished), methodology, and reporting prevented analytical comparison and should be imposed in future studies. [ABSTRACT FROM AUTHOR]

Taking a conventional implant abutment-level impression with the gingival retraction technique can cause side effects such as gingival recession and bleeding. In order to overcome these problems, an impression technique using digital superimposition of the customized abutment has been newly introduced. In this technique, digital impression data and prescanned abutment data are superimposed to reproduce the abutment's location and shape on computer-aided design software. The present investigation was conducted to evaluate the clinical accuracy of the newly adapted digital superimposition impression technique by assessing the fit of fabricated prostheses. The results showed clinical efficacy of this technique, showing clinically acceptable marginal and internal fit and convenience. [ABSTRACT FROM AUTHOR]

Purpose: To assess the clinical, technical, and esthetic outcomes of directly veneered zirconia abutments cemented onto non-original titanium bases over 3 years.Materials and Methods: A total of 24 healthy patients with a single missing tooth in the maxilla or mandible (incisors, canines, or premolars) received a two-piece implant with a screw-retained veneered zirconia restoration extraorally cemented on a titanium base abutment. Baseline measurements and follow-up examinations were performed at 6 months, 1 year, and 3 years following loading. Radiographic, clinical, technical, and esthetic parameters were assessed. Wilcoxon signed rank test was used to analyze the data.Results: Mean marginal bone levels measured 0.54 ± 0.39 mm (median: 0.47 mm, range: 0.07 mm to 1.75 mm) at baseline and 0.52 ± 0.39 mm (median: 0.39 mm, range: 0.06 mm to 1.33 mm) at 3 years. Mean probing depth around the implants increased from 3.0 ± 0.6 mm at baseline to 3.8 ± 0.8 mm at 3 years (P = .001). Bleeding on probing changed from 27.1% ± 20.7% (baseline) to 51.5% ± 26.1% (3 years) (P = .001). The mean plaque control record amounted to 11.1% ± 21.2% (baseline) and 14.4% ± 13.89% (3 years) (P = .261). Two implants were lost at 3.5 and 30 months postloading due to peri-implantitis, resulting in a 91.7% implant survival rate. Patient satisfaction was high at 3 years.Conclusion: Zirconia restorations cemented onto the tested non-original titanium bases should not be recommended for daily clinical use, as they were associated with significant increases in BOP and PD values and varying marginal bone levels 3 years after placement. [ABSTRACT FROM AUTHOR]

Purpose: To compare the precision of adaptation of cobalt-chromium (Co-Cr) three-unit fixed dental prostheses (FDPs) fabricated using different techniques. Materials and Methods: A master model was prepared to receive a three-unit FDP. This model was duplicated 60 times from a silicone mold. The dies (N = 60) were scanned and divided into three groups (n = 20 each) to receive the FDPs made of pre-sintered Co-Cr (CS), laser-sintered Co-Cr (LS), or cast Co-Cr (Gi). Frameworks were layered with ceramic, and each framework was seated on its specific model. The replica technique was used to measure the marginal and internal discrepancies in the mesiodistal and buccolingual planes. Prepared silicone samples were examined with scanning electron microscopy. Obtained data were analyzed using Levene test, t test, and analysis of variance (α = .05). Results: When overall mean discrepancy values were compared, in mesiodistal planes, LS showed better adaptation than Gi (P = .025). Similar adaptation was found for CS and Gi, and for CS and LS (P = .169 and P = 1.000, respectively). In buccolingual planes, the difference in fit was not significant among the three tested groups (P > .05). In a pairwise comparison between materials, a net increase in values between points 1 and 5 was noted (P = .57). Difference in discrepancy values within points was significant. This was confirmed at abutment level on some measurement points. Within each material, at abutment level, differences were significant at several measurement locations in both the mesiodistal and buccolingual planes. Conclusion: Within the limitations of this study, three-unit Co-Cr FDPs showed similar marginal and internal discrepancy values. Presintered and laser-sintered Co-Cr alloys can be considered for three-unit FDP fabrication. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate studies with a minimum follow-up of 3 years to find the peri-implant marginal bone loss (MBL) and rate of implant failure with platform-switching (PS) and platform-matching (PM) implant-abutment connections. Materials and Methods: A systematic review and meta-analysis was done based on the preferred reporting items for systematic reviews and meta-analyses guidelines, with a focused question on population, intervention, comparison, and outcome. The Cochrane Collaboration's Risk of Bias tool was used to assess bias. Randomized controlled trials (RCTs) comparing peri-implant MBL and implant failure in patients receiving PS implants and PM implants only were included. The risk ratio (RR) of the implant-abutment connection and implant failure was calculated, and peri-implant MBL was expressed in mean differences (MD) at 95% confidence intervals (CIs). Results: Three hundred eighty-one articles were obtained after an initial literature search. Finally, nine articles were included in the study that fulfilled the inclusion criteria. Four hundred twenty-six PS and 411 PM implants were placed with 16 implant failures (8 PS and 8 PM). The implant survival rate was 98.12% for the PS group, and 98.05% for the PM group, with no statistically significant difference (P = .97). The mean peri-implant MBL with the PS implant was lower (0.33 ± 0.41 mm) compared with the PM implant (0.66 ± 0.42 mm). A significant effect of PS implants was found in reducing peri-implant MBL (MD: -0.70, 95% CI: -1.25,-0.15; P = .01) compared with PM implants. The MD of peri-implant MBL between the PS and PM implants decreases with increased follow-up: MD of 0.69 (P = .15) with follow-up of = 3 years but < 5 years, and MD of 0.62 (P = .04) with follow-up of = 5 years. Conclusion: Reduced peri-implant MBL was found with the PS concept. The peri-implant MBL decreases with an increased mismatch between the abutment and implant platform. The difference in peri-implant MBL in PS and PM implants in the maxilla was greater and favored the PS concept. Bone-level implants with single crowns or splinted prostheses better preserved the peri-implant marginal bone with the PS concept. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the clinical, radiographic, and prosthetic outcomes of a single custom CAD/CAM abutment system on implants from four manufacturers, with a mean clinical service of 4 years in a retrospective, multicenter case series study. Materials and Methods: Adult subjects (n = 142) previously restored with titanium or gold-shaded titanium nitride custom CAD/CAM abutments (Atlantis, Dentsply Sirona; n = 259) connected to implants from four different manufacturers (Dentsply Sirona Implants [AT], Biomet 3i [BM], Nobel Biocare [NB], Straumann [ST]), irrespective of implant-abutment interface, and replacing one or more teeth in any position were recalled for a single-visit examination by calibrated investigators at six university clinics. The primary outcomes evaluated included abutment success and survival; secondary outcomes included assessment of papillae fill, probing pocket depth (PD), bleeding on probing (BOP), marginal bone levels (MBLs), and patient-reported outcome measures (PROMs). Results: Two-hundred fifty-five (98.5%) abutments supported cement-retained restorations, and four (1.5%) abutments supported screw-retained restorations. Forty-two patients had 64 AT implants (25%), 31 patients had 61 BM implants (24%), 26 patients had 50 NB implants (19%), and 43 patients had 84 ST implants (32%). The overall implant-CAD/CAM abutment success rate was 92.66% (95% CI: 88.78%, 95.53%) for all implants examined, and the survival rate was 98.84% (95% CI: 96.65%, 99.76%) for all implants evaluated. The Jemt papillae index demonstrated a minimum of at least 50% to complete fill of the interproximal papillae in 65.0% of sites. PDs had a median value of 3.0 mm, and BOP was present on 19% of abutment surfaces. Mean MBL changes from the time of placement to exam were -0.24 ± 0.99 mm (-4.9 to 2.3; P = .058) for mesial sites and -0.32 ± 0.96 mm (-4.9 to 2.1; P = .000) for distal sites. PROMs expressed 93% of patients reporting good to very good masticatory function, 97% of patients reporting being satisfied or very satisfied with their esthetic outcomes, and 94% of patients indicating that they were satisfied or very satisfied with their overall implant-restorative outcomes. Conclusion: This retrospective, multicenter clinical study of FDA 510k-approved titanium CAD/CAM abutments of a single manufacturer on multiple implant systems demonstrated high levels of success and survival as well as stable peri-implant tissue outcomes, reflected by overwhelmingly positive PROMs. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to compare the clinical influence of immediate individualized CAD/CAM healing abutments and conventional healing abutments on peri-implant soft and hard tissue in shaping the emergence profile. Materials and Methods: Patients with a single maxillary incisor missing who accepted dental implantation were registered in this study. After implantation, individualized CAD/CAM healing abutments and regular prefabricated abutments were randomly inserted to shape the emergence profile. A radiograph was taken, and the pink esthetic score, papilla height, papilla proportion, and probing depth were recorded at 6 months after implant placement (T1), loading (T2, definitive restoration), and 1 year after loading (T3). Patient self-assessment scores were also evaluated through the visual analog scale. The data were analyzed statistically using the t test or repeated-measurements analysis of variance (ANOVA). Results: Twenty patients were enrolled in this study, including 9 patients using individualized abutments and 11 patients using conventional abutments. The mean total marginal bone level in the individualized abutment group was 1.53 ± 0.65 mm at implant placement, 1.10 ± 0.47 mm at loading, and 0.76 ± 0.47 mm at 1 year after loading. In contrast, the mean total marginal bone level in the conventional abutment group was 0.62 ± 0.39 mm at implant placement, 0.14 ± 0.55 mm at loading, and -0.04 ± 0.53 mm at 1 year after loading. The differences between the individualized abutment group and conventional abutment group were statistically significant for the mesial and distal marginal bone level at three time points, respectively (P = .05). Similarly, there were significant differences in probing depth, papilla height, and pink esthetic score between the two groups. Conclusion: This immediately individualized healing abutment protocol may significantly preserve the peri-implant marginal bone and soft tissue. The use of individualized CAD/CAM healing abutments for shaping the emergence profile shows better esthetic outcomes than conventional healing abutments. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this systematic review was to evaluate the influence of zirconia and titanium as abutment materials on peri-implant soft tissue color. Materials and Methods: The searched electronic databases included MEDLINE/PubMed, LILACS, Web of Science, Scopus, and LIVIVO. Two types of studies were included: randomized clinical trials (RCTs) and controlled clinical trials (CCTs) that compared zirconia (Zr) and titanium (Ti) abutments. The outcomes measured were as follows: implant crown esthetic index, visual analog scale, esthetic index, gingiva discoloration index-spectrophotometry, papilla index, recession index, and pink esthetic score. Two reviewers selected the records, assessed quality, and extracted data of included studies independently. Results: A total of 323 patients enrolled in 13 studies were included in this analysis with 11 RCTs and 2 CCTs. Due to the wide variety of methodologies used, meta-analysis was only possible for RCTs that performed spectrophotometric analysis. The use of zirconia or titanium for implant abutments does not seem to be the principal factor for influencing peri-implant soft tissue color. The meta-analysis showed no difference between zirconia and titanium abutments. Conclusion: This study does not support any better advantage of the use of zirconia in comparison to the use of titanium related to peri-implant tissue color. [ABSTRACT FROM AUTHOR]

This article evaluated the sealing capacity of single crowns made of a new zirconia (Katana STML, Kuraray Noritake) when cemented with two different cement types and two different marginal preparation types. Forty intact human anterior teeth, extracted for periodontal reasons, were used. Each sample was prepared with two margin preparations: knife-edge (KE) on one half of the tooth and chamfer (CH) on the other half. Based on the type of cement used, abutments were randomly distributed into one of two groups: Group 1 used resin cement (Panavia V5, Kuraray Noritake), and Group 2 used reinforced glass-ionomer cement (FujiCEM 2, GC). A digital workflow was utilized for crown fabrication. After the cementing procedures, samples were processed, and microleakage and scanning electron microscopic observations were made. Microleakage varied significantly depending on the type of cement combination used. Group 1 samples showed less microleakage (medians: 0.76 for CH and 0.51 for KE in Group 1, and 4.1 and 3.45 for Group 2, respectively) than Group 2 specimens; the difference was statistically significant (P < .000). KE preparation showed less microleakage than CH, although no statistically significant differences were found (P < .0558). Under microscopic observations, some samples showed internal fractures within the zirconia material. KE and CH seal the margin of zirconia crowns similarly. The resin cement system ensured better adhesion than reinforced glass-ionomer cement [ABSTRACT FROM AUTHOR]

Sandblasting materials used for dental restoration are a valuable preconditioning technique that enhances the physical properties and promotes osseointegration and cell adhesion. Triplicate groups of Ti medical grade 4 and Ti6Al4V were blasted with 16 series of various naturally occurring and synthetically produced spraying materials of controlled granulometry at three spraying durations each and two spraying pressures, and the results were tested for the determination of the surface roughness taken as an average of 80 points ±5 points for each particular series of operating parameters. SEM analysis and specific tests to see whether or not cell cultures proliferate on the treated materials were also conducted. It was found that in all cases, regardless of the spraying material or working conditions, the roughness profile achieved is a uniformly distributed one. A reduction in the blasting pressure by half led to a decrease in the roughness between 30 and 35%. The use of glass balls as blasting material led to decreased roughness and more uniformly distributed roughness values for Ti as well as for Ti6Al4V, regardless of spraying duration or applied pressure compared to other spraying materials. Blasting with olivine led to increased, as well as uniformly distributed, values, and hence the conclusion that one may control the roughness size by choosing one or another of the above materials without the need to change any other operating parameters. In the case of Ti, the achieved roughness is greater than in the case of Ti4Al6V, regardless of the blasting material; the differences are smaller the softer the sandblasting material due to the fact that Ti alloys have better mechanical properties and increased hardness compared to pure Ti. SEM analysis showed that the use of sintered hydroxyapatite as an additive to the blasting material does not necessarily lead to a substantial deposition of hydroxyapatite on the substrate materials; only traces of it were identified during the analysis. As a general conclusion, this study showed that by sandblasting Ti and Ti6Al4V with different spraying materials, one may control the surface roughness, and this technique may be an attractive method for preconditioning these materials for restorative dentistry.

Monolithic zirconia implant-supported restorations connected to titanium bases or titanium inserts are increasing in popularity due to their application in a full digital workflow. These prefabricated abutments are connected to the all-ceramic superstructure by adhesive cementation. Although limited clinical data on the outcomes of this type of restoration are available, a few laboratory studies have shown possible debonding issues. This case report presents a bonding failure of a fixed dental prosthesis supported by titanium bases after short clinical use. A treatment alternative is also proposed using the available digital dental technology. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this systematic review with meta-analysis was to compare the survival rate of single crowns supported by extra-short implants (≤ 6 mm) to those supported by conventional implants, with or without previous maxillary sinus augmentation. The proportion of failures was described according to the type of complication and follow-up periods. Materials and Methods: Randomized and prospective clinical trials were selected from six databases and gray literature. The risk of bias was evaluated by Joanna Briggs Institute Critical Appraisal Checklist, and the certainty of the evidence was analyzed with Grading of Recommendations Assessment, Development, and Evaluation. Meta-analyses were processed with RevMan and MedCalc Statistical Software. Results: Single crowns supported by extra-short implants had a similar risk of failure to those supported by conventional implants, regardless of previous maxillary sinus augmentation (P > .05). Overall failure proportion of extra-short implants was 5.19%, but it varied according to follow-up (1.18% before loading, 1.56% at 12 months, 1.20% at 24 months, 2.10% at 48 months). Biologic failure complications were 37.90% for bleeding on probing, 22.45% for peri-implantitis, and 11.29% for infection. Prosthodontics failure complications were 14.88% for abutment failures and 14.73% for prosthetic screw loosening. Considering the risk of bias, most studies were classified at moderate risk. Conclusion: The risk of failure of single crowns supported by extra-short implants is similar to those supported by conventional implants, regardless of previous maxillary sinus augmentation or follow-up period. The most frequent biologic and prosthetic complications were bleeding on probing and abutment failures, respectively. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this investigation was to assess the extent of mucosal discoloration caused by different CAD/CAM abutment materials and to determine the influence of mucosa thickness on the subsequent color, with a particular focus on titanium nitride. Materials and Methods: In a pig maxilla, a trapdoor-shaped mucosa flap was prepared unilaterally. Several CAD/CAM abutment materials were used to assess a number of clinical scenarios. Varying mucosa thicknesses were simulated by connective tissue grafts harvested at the contralateral side of the palate, resulting in layer thicknesses of 1.5, 2, and 3 mm. Titanium (Ti), zirconia (ZrO2), and titanium nitride (TiN) served as test specimens with and without ceramic veneering. Color differences (ΔE) and deviations in brightness (L), chroma (C), and hue (H) were determined spectrophotometrically, comparing the measured value of the native tissue and the results obtained with different materials at varying mucosa thicknesses. Results: All tested specimens caused a mucosa discoloration in comparison to the native tissue, diminishing with increasing mucosa thickness. The use of TiN demonstrated the least mucosa discoloration in thin soft tissue of 1.5 mm, with a mean ΔE value of 1.93 (P = .004). While ZrO2 revealed a comparable ΔE value of 2.13 (P = .022) at a tissue thickness of 1.5 mm, Ti showed the highest mucosa discoloration above the visibility threshold of ΔE = 3.1, with a mean ΔE value of 4.07 (P = .002). Ceramic veneering of the Ti samples led to a considerable reduction in soft tissue discoloration, with a resulting ΔE value of 2.2. The veneering of TiN and ZrO2 samples with porcelain, on the other hand, had no noticeable effect on the mucosa color. Conclusion: CAD/CAM abutment materials cause an adverse soft tissue color shift that decreases with increasing mucosa thickness. In thin peri-implant mucosa, titanium nitride and zirconia lead to the least discoloration. Due to their positive optical properties and mechanical superiority compared with ceramic abutments, gold-hue titanium nitride-coated CAD/CAM abutments could be a clinical alternative in cases of thin peri-implant mucosa. [ABSTRACT FROM AUTHOR]

Purpose: To assess the impact of abutment angulation on loosening torque, torque loss, and percentage of torque loss in the prosthesis and abutment screws after aging of the implant-supported prosthesis. Materials and Methods: Fifty epoxy maxillary casts with missing central, lateral, and canine teeth were used, and each cast received two implants. All casts were divided into five groups (n = 10): (1) both implants received straight abutments (0-0); (2) the central implant received a straight abutment and the canine implant received a 17.5-degree angled abutment (0-17.5); (3) the central implant received a straight abutment and the canine implant received a 35-degree angled abutment (0-35); (4) both implants received 17.5-degree angled abutments (17.5-17.5); and (5) both implants received 35-degree angled abutments (35-35). For each cast, a three-unit zirconia restoration was fabricated, and a torque meter was utilized to tighten the abutment screw (25 Ncm) and prosthesis screw (18 Ncm). The reverse torque value was recorded for each screw. All restorations were subjected to 3,500 thermal cycles between 5°C and 55°C and load cycled for 150,000 cycles with 50-N load. After the loosening torque was measured for each screw, the torque loss and percentage of torque loss were calculated. Results: There was a statistically significant difference in the torque loss of the central prosthesis screw (P < .001) and canine prosthesis screw (P < .001) between study groups. The 35-35 group showed the highest percentage of torque loss, while the 0-0 group showed the lowest value. A significant difference was found regarding the torque loss of the central abutment screw (P < .001) and canine abutment screw (P < .001). The abutment screws of the 35-35 group showed the highest percentage of torque loss, while the 0-0 groups showed the lowest percentage of torque loss. Conclusion: Screw loosening of the prosthesis and abutment screws increases with increasing abutment angulation after aging. In the same fixed prosthesis, the torque loss in the prosthesis and abutment screws was higher in canine screws employing different angled abutments. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to determine the effect of solid (one-piece) and two-piece abutments on the stress profile of narrow implants with marginal bone loss. Materials and Methods: Solid and two-piece abutments were connected to a conical internal octagon-connection implant (3.3 mm in diameter, 10 mm in length) and restored with a single crown. Three-dimensional finite element analysis was used to simulate the stress distribution in implant models with different levels of marginal bone resorption (0, 1, 2, and 3 mm). The effect of the design variables under increased bone resorption scenarios, including abutment screw length and diameter, was assessed. Static loading was applied to determine the mechanical response of the implant and cortical and trabecular bone. Results: Marginal bone resorption levels dominated the mechanical response under static loading conditions. A marginal bone loss of 3 mm significantly increased stress values in the implant vicinity and abutment screw. Both abutment designs displayed similar stress distribution in the surrounding bone, but lower stress values were observed in the implant body with two-piece abutments. The abutment screw length was more effective in the resultant stress, as the longer screws reduced the stress in the implants. Conclusion: Marginal bone resorption magnitude is the crucial parameter in biomechanics to determine the mechanical behavior. As bone loss increases, resultant stress around implants under mastication forces may lead to implant failure, regardless of abutment type. [ABSTRACT FROM AUTHOR]

The purpose of this randomized clinical study was to evaluate the efficacy of platform-switching (PS) vs platform-matching (PM) implants when paired with a newly designed marginless abutment (MA) vs a conventional abutment (CA) in maintaining peri-implant tissue stability. Marginal bone level (MBL) and probing depth were measured up to 1 year postloading. Eighty implants were inserted in 42 patients and randomly assigned to one of four groups, each with a different implant/abutment configuration: Group 1 (PM+CA), Group 2 (PM+MA), Group 3 (PS+CA), and Group 4 (PS+MA). Data were collected at implant placement (T0), abutment placement (T1), final crown placement (T2), and 1 year postloading (T3). At the 1-year follow-up, MBL was more stable in Groups 3 and 4 compared to Groups 1 and 2. These results suggest that the role played by the implant-abutment connection (PS vs PM) is more important than the type of abutment preparation (MA vs CA). [ABSTRACT FROM AUTHOR]

Purpose: To introduce a new method for labiopalatal positioning and angulation of immediately placed dental implants in the anterior maxilla with relation to the type of abutment used (straight/angled abutment). Materials and Methods: CBCT scans from the database of a private practice were searched for patients who received immediate implants in the anterior maxilla. After superimposition of the initial and postoperative scans, the incisor root angle (IRA), incisor implant angle (IIA), and the difference between these angles were measured. An assessment was then made about whether the implant position would be within the safe angle or not. Age, sex, tooth/implant site, and type of prosthetic abutment (straight/angled) were retrieved from the patients' records. Results: A total of 74 patients with 95 immediate implants altogether were selected for analysis. In regard to the type of abutment, 76 (80%) were straight, and 19 abutments (20%) were angled. Regardless of abutment type, 72 implants (75.8%) were placed within the safe angle, while 23 implants (24.2%) were placed outside it. All 19 implants with angled abutments were placed outside the safe angle. There were statistically significant associations between placement within the safe angle and type of abutment (P < .001; OR = 19), IRA (P < .001; effect size = 0.904), difference between IIA and IRA (P < .001; effect size = 1.209), and sex (P < .001; OR = 2.995). There was no statistically significant association between placement within the safe angle and IIA (P = .757, effect size = 0.063), site (P = .200; effect size = 0.184), or age (P = .387; effect size = 0.208). There was a statistically significant association between the type of abutment and the IRA (P = .001; effect size = 0.762) as well as the difference between IIA and IRA (P < .001; effect size = 1.056). Conclusions: The safe angle concept can be used as a reliable planning tool to determine the correct implant positioning for immediate implant placement in the anterior maxilla. Applying the safe angle concept will reduce the need for angled abutments for prosthetic correction. [ABSTRACT FROM AUTHOR]

The interface between a dental implant and an abutment is stabilized by two mechanical characteristics: a preload of an abutment screw and the friction between the contact surfaces of the implant and the abutment. These mechanical properties are quantitatively analyzed by using physical and mechanical formulas. The important thing is that such mechanical properties cause various biological phenomena when medical devices are inserted into human bodies. Some mechanical complications in dental implant prostheses are closely associated with biological complications. This literature review explores the mechanical complications of the implant–abutment connection and their biological effects in a titanium dental implant system, which is the system most widely used in dental clinics. Understanding the biomechanics of the implant–abutment connection helps to predict the merits and limits of zirconia dental implants, which have been recently introduced and clinically applied.

Statement of problem: The relation between cement color and abutment substrate material and the corresponding effect on the color accuracy of high-transparency pre-colored zirconia (HT-Zr) remains unclear. Purpose: This in-vitro study aimed to investigate the difference in color accuracy when the HT-Zr is bonded to different materials-based substrates with differently colored resin cement. Materials and methods: Vita A1 shade HT-Zr with 1 mm thickness was used as the testing sample. The samples were first placed on zirconia (ZR), tooth color resin (CR), and metallic (MT) abutment substrates. Subsequently, four differently colored cements (translucent (TR), bleach, opaque, and A2 shade (A2)) were used for bonding HT-Zr onto the substrate, and the non-bonded group was used as the control group (CG). There were 15 groups in total (n = 10 per group). A digital colorimeter was used to obtain Commission Internationale de l’Eclairage (CIELab) color parameters. The translucency parameter (TP00) of the substrate and sample, as well as color difference (ΔE00) and chroma (C) between the different groups were calculated. Additionally, the ΔE00 and TP00 were compared with the moderately unacceptable match of ΔE00 = 3.6. The statistical analysis was conducted using ANOVA and Tukey HSD post-hoc test (α = 0.05). Results: HT-Zr exhibited high translucency (TP00 = 11.02 ± 0.18), and the mean ΔE00 of the testing samples ranged between 2.18 ± 0.20 and 13.14 ± 0.31. The ZR-CG and MT-A2 groups showed the highest and lowest lightness separately. The CR-CG group exhibited the highest C, and the ΔE00 was lower than that of 3.6. The MT-TR group showed the lowest C and the highest ΔE00. The inter-group comparison revealed that the ΔE00 for different cement is mostly lower than the acceptable color match of 1.0; moreover, the ΔE00 for all the substrates, excluding the CG group, is higher than 3.6. Conclusions: The abutment substrate materials and the cement color should be considered with caution when using HT-Zr, with the effect of abutment substrate materials being more apparent in color accuracy. HT-Zr restorations are not recommended for discolored or bleached abutments but only for natural-colored abutments to achieve the optimal color appearance.

Background: Premature loss of primary molars can be treated with a band loop space maintainer (SM). However, fabricating a conventional band loop SM requires multiple clinical and laboratory procedures, which can potentially affect the accuracy of the SM. Moreover, the conventional SM is unable to fully restore masticatory function and maintain the vertical dimension of the edentulous space. In this current study, a fully digital workflow to fabricate a semi-rigid bridge SM made from polyetheretherketone (PEEK) has been described and evaluated for its clinical effectiveness. Methods: A total of 15 children (eight males and seven females) between the ages of 4–8 years, who experienced the premature loss of a single primary molar, were included in this study. Digital impressions were taken using the CEREC CAD/CAM chair system and imported into CAD software to design the semi-rigid bridge SM, which was fabricated using PEEK block as the maintainer material. The digital SM was tried-in and bonded to the abutment with resin cement. The edentulous space was measured immediately after bonding (T0) and 1 month (T1), 3 months (T2), and 6 months (T3) after treatment. The periodontal condition and mobility of the SM and abutment were also examined. Results: The use of digital impressions resulted in a decreased occurrence of the pharyngeal reflex. The digital semi-rigid bridge SM, fabricated with PEEK, was both convenient and aesthetically pleasing, and successfully restored the anatomy and masticatory function of the missing primary molar. None of the 15 semi-rigid bridge SMs or abutments became loose or fell off during the study, and only one child presented with gingivitis. Furthermore, the difference in the edentulous space at T0, T1, T2, and T3 was not statistically significant (all P > 0.05). Conclusions: The digital semi-rigid bridge SM fabricated with PEEK was clinically effective in maintaining the missing space and had advantages over the traditional band/crown loop SM. [ABSTRACT FROM AUTHOR]