Search

Objectives: To evaluate clasp-retained removable partial dentures (C-RPDs) with a metal framework for survival, maintenance requirements, and biologic implications. Method and materials: C-RPDs were retrospectively analyzed based on patient records. Treatment failure was defined as fracture of a framework component (metal base or connector) or loss of an abutment tooth. Other outcome variables included factors that might conceivably impact C-RPD survival (maxilla vs mandible, Kennedy classes, opposing dentitions, treatment by students vs certified dental practitioners), mobility and caries of abutment teeth (in relation to clasp designs), and maintenance requirements (relining, clasp or resin fractures). Differences were evaluated by appropriate statistical tests at the P≤.05 level. Results: A total of 612 patients (339 men, 273 women) 60.0±11.5years old at delivery were included, covering 842 C-RPDs and a mean observation period of 42.1±33.2months. Kaplan-Meier C-RPD survival was 76.2% after 5years and 49.5% after 10years. Biologic complications (ie, loss of abutment teeth) accounted for the vast majority (95.6%) of C-RPD failures, and Kaplan-Meier C-RPD survival was significantly better in the mandible (P=.015). Some clasp designs contributed significantly to caries and removal of abutment teeth (both P<.05). No other significant differences were noted. Conclusion: Tooth loss both emerges as the main cause of C-RPD failure and might be amenable to careful selection of clasp designs. Overall, better C-RPD survival should be expected in the mandible. A noncon-tributory role of Kennedy classes and opposing dentitions is tentatively suggested based on numerically heterogenous subgroups. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the esthetic outcomes based on the color differences in zirconia (Zr) of varying thickness, resin cement color, and types of titanium (Ti) implant surface treatments. Materials and Methods: Overall, 28 high-translucency monolithic zirconia (HTMZ) specimens were arranged into four groups based on Zr thickness: 1.0, 1.5, 2.0, and 2.5 mm (n = 7 per thickness). Each group was tested using two resin cement colors (clear and opaque) in combination with six surface-treated Ti groups (n = 7), including untreated titanium (UT), anodization (AN), 50-µm alumina airborne-particle abrasion followed by AN (SBAN), AN followed by 50-µm alumina airborne-particle abrasion (ANSB), 9.5% hydrofluoric acid followed by AN (HFAN), and AN followed by 9.5% hydrofluoric acid (ANHF). This created a total of 48 experimental groups, including the use of composite resin (n = 7, shade A2D) for four control groups. All specimens were measured using a spectrophotometer and subsequently compared with composite resin (control) with the corresponding Zr thickness to establish color differences. A color difference of < 2.7 was considered clinically acceptable. The data obtained were statistically analyzed using ANOVA and post hoc test (P = .05). Results: Zr thickness, resin cement color, and type of Ti implant surface treatment significantly affected the observed color differences (P < .05). When using 2.5-mm HTMZ with clear resin cement on AN, UT, SBAN, HFAN, and ANSB, the mean color differences were below the clinically acceptable values, and the 95% CIs of color differences were below the clinically acceptable values for AN, UT, and SBAN groups. Conclusions: HTMZ with a minimum thickness of 2.5 mm and clear resin cement on AN, UT, and SBAN groups potentially result in acceptable color matching with 95% CIs. [ABSTRACT FROM AUTHOR]

This study compared the survival, marginal bone loss (MBL), and prosthetic complications of 4.5-mm extra-short implants and longer implants splinted to the short implants via the restoration. A retrospective controlled cohort study was performed. The 4.5-mm extra-short group (study group; SG) included 48 consecutively placed implants. The control group (CG) included 48 implants splinted to the extra-short implants. The same surgical team treated the 39 included patients, and all implants were restored with a screw-retained fixed restoration and intermediate abutments. Immediate and conventionally loaded implants were included. All implants were in function during the follow-up period (14 ± 3.4 and 17 ± 13 months for SG and CG, respectively). No differences in technical complications were observed between the groups (one and two cases of screw loosening for SG and CG, respectively; two provisional prosthesis fractures for SG; P = .310). Marginal bone stability was similar for SG and CG at the mesial level (-0.01 ± 0.28 mm for SG vs -0.18 ± 0.72 mm for CG; P = .270) and at the distal level (0.02 ± 0.39 mm for SG vs -0.18 ± 0.68 mm for CG; P = .076). The same good clinical performance could be observed for 4.5-mm implants and longer implants under the same prosthesis. [ABSTRACT FROM AUTHOR]

Purpose: To develop the most compatible cementation protocol for ensuring minimal residual cement and optimal retention of cement-retained implant-supported fixed dental prostheses. Materials and Methods: A total of 30 custom implant abutments and zirconia crowns with bilateral wings were prepared. Three cement types were used for cementation: noneugenol resin cement (Premier Implant Cement; Group IC), dual-polymerizing self-adhesive resin cement (SmartCem2; Group SC), and zinc oxide eugenol cement (Temp-Bond; Group TB; n = 30 per group). Three cementation methods were applied for each cement type, and the samples were divided into subgroups: (1) cement was injected using a graduated syringe (ICN, SC-N, and TB-N); (2) a cementation jig made with a silicone impression material and temporary resin material was used (IC-CJ, SC-CJ, and TB-CJ); (3) 3D-printed abutments were used as replicas for cementation (IC-3DP, SC-3DP, and TB-3DP). The amount of cement injected, surface area of the residual cement, and retentive strength were measured. Kruskal-Wallis and post-hoc Mann-Whitney tests were used for statistical analyses. Results: Excess cement was not observed when cementation jig or 3D-printed replicas were used. For IC and SC subgroups, non-use of these auxiliary tools resulted in significantly higher amounts of injected cement. The retentive strength differed significantly among the IC subgroups but not among the SC subgroups. The retentive strength of subgroups TB-N and TB-CJ was significantly higher than that of subgroup TB-3DP. Conclusions: To prolong the main purpose of each cement type, a cementation jig or 3D-printed replica is highly recommended regardless of the cement type. [ABSTRACT FROM AUTHOR]

Purpose: To assess the survival of double-crown-retained implant-and-tooth-supported removable partial dentures (DCR-ITSRPDs), evaluate abutment survival, and identify first aftercare measures. Materials and Methods: The influence of various factors on the survival of the DCR-ITSRPDs and the abutments were observed in this retrospective and clinical follow-up study using the Kaplan-Meier estimate. In addition, the first-required aftercare measure for each prosthesis was evaluated. Results: In total, 47 DCR-ITSRPDs were investigated (mean observation: 4.3 ± 3.8 years; max: 14.3 years), 3 of which (6.4%) had to be replaced. The survival probability for DCR-ITSRPDs was 100% at 5 years and 75% at 10 years. A total of 297 abutments (120 natural teeth and 177 dental implants) were observed, 22 of which (7.4%; 6 teeth and 16 implants) failed. The survival probability for teeth was 90.2% at the 5- and 10-year mark; for dental implants, it was 90.4% at 5 years and 76.3% at 10 years. Conclusions: DCR-ITSRPDs are a successful and durable treatment option for patients with substantially reduced residual dentitions. Both prostheses and abutments show good survival times after 5 and 10 years in function. The patient-associated factors tested showed no influence on the survival of DCR-ITSRPDs and abutments. Peri-implant infection was the decisive factor for abutment loss; therefore, regular dental prophylaxis and examinations are of major importance. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effect of taper, length, angle, and number of vertical axial walls on the retentive strength of a cemented crown on a partially customized hybrid abutment in the esthetic zone. Materials and Methods: A total of 35 metal copings were used and divided into two groups. One group had 30 copings cemented to their corresponding 8-degree tapered abutment with lengths from 3 to 8 mm, increasing in 1-mm increments (5 copings per length). The other group had the remaining 5 copings and consisted of a standardized metal coping that matched a hexagonal abutment with 3-mm vertical axial walls and the sequential removal of 1, 2, and 3 contiguous vertical axial walls. Dislodgment tests were performed for all copings in both groups. Maximum retentive forces were measured in retentive strength (kgF), with a conversion factor of 9.807 N = 1 kgF. Results: At each tapered abutment length, the retentive strength increased proportionally and was significantly different, ranging from 31.67 ± 4.10 kgF to 67.68 ± 11.22 kgF (F [5,24] = 20.46, P < .001). An unmodified hexagonal abutment demonstrated the highest retentive strength (70.15 ± 12.97 kgF). The sequential removal of 1, 2, and 3 contiguous vertical axial walls of the hexagonal abutment resulted in retentive strength values of 59.89 ± 10.06 kgF, 57.01 ± 9.62 kgF, and 55.99 ± 9.35 kgF, respectively, with no significant difference (P > .05) in strength. Conclusions: A partially customized abutment with vertical axial walls on one side and a profile reduction on the opposite side can provide comparable retention to cemented copings at one-third the length and at one-sixth the surface area of an 8-mm abutment with an 8-degree taper. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the screw loosening and fracture resistance of different hybrid abutment crown restorations after thermomechanical aging. Materials and Methods: Restorations were produced from zirconia, lithium disilicate, and hybrid ceramics with a CAD/CAM system (n = 10). Restorations and titanium bases (Ti-bases) were cemented, and the abutment screws were torqued to 30 Ncm. They were retorqued after 10 minutes, and then the removal torque values (RTVs) were measured. After 250,000 and 500,000 cycles of thermomechanical aging were completed, the RTVs were measured again, and removal torque loss (RTL) ratios were calculated. The specimens were subjected to a fracture resistance test after 750,000 cycles of thermomechanical aging, and the load at failure was recorded as the fracture resistance (N). The results were statistically analyzed (a = .05). Results: Aging was effective on the RTVs and RTL ratios (P < .001). The highest RTV was observed before aging; however, the RTVs significantly decreased and RTL ratios significantly increased after aging (P < .05). The fracture resistance values significantly differed among the ceramic materials. All lithium disilicate and hybrid ceramic specimens showed restoration fracture and most of the zirconia specimens showed Ti-base-related failure. Conclusions: Hybrid abutment crowns made of zirconia, lithium disilicate, and hybrid ceramics can withstand the average occlusal forces in the molar region; however, the ceramic type may affect the failure type. Retightening of the abutment screws after 10 minutes following the first tightening and annually may be beneficial to prevent the adverse effects of screw loosening on the integrity of the implant-abutment connection. [ABSTRACT FROM AUTHOR]

Purpose: To examine the behavior and function of human gingival fibroblasts growing on healing abutments with or without laser-textured topography. Materials and Methods: Human primary gingival connective tissue fibroblasts were cultured on healing abutments with machined or laser-textured (Laser-Lok, BioHorizons) surfaces. Cellular and molecular responses were evaluated by a variety of tests, including cell density assay (WST-1), fluorescence microscopy, real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and detachment tests. Results: The machined surface showed monodirectional traces and scratches from milling, whereas the laser-textured surface showed a distinct morphology consisting of monodirectional mesoscale channels (15-µm pitch) and woven oblique microridges formed within the channels. There were no differences in initial fibroblast attachment, subsequent fibroblast proliferation, or collagen production between the machined and laser-textured surfaces. Fibroblasts growing on a laser-textured surface were found to spread in one direction along the mesochannels, while cells growing on machined surfaces tended to spread randomly. Fibroblasts on laser-textured surfaces were 1.8 times more resistant to detachment than those on machined surfaces. An adhesive glycoprotein (fibronectin) and transmembrane adhesion linker gene (integrin ß-1) were upregulated on laser-textured surfaces. Conclusions: The increased fibroblast retention, uniform growth, and increased transcription of cell adhesion proteins compellingly explain the enhanced tissue-level response to laser-created and hybrid-textured titanium surfaces. These results provide a cellular and molecular rationale for the tissue reaction to this unique surface; in addition, they support its extended use, from implants and healing abutments to diverse prosthetic components where enhanced soft tissue responses would be desirable. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate four decontamination strategies utilizing enzymatic agents available in most clinical settings to determine (1) the amount of biomaterial that can be removed in a group of previously used healing abutments (uHAs) and (2) the degree to which the decontaminated HAs are capable of inducing an inflammatory response in vitro compared to new HAs. Materials and Methods: In total, 50 HAs were collected following 2 to 4 weeks of intraoral use and distributed randomly into five test groups (groups A-E; n = 10 per group). Group A used enzymatic cleaner foam and an autoclave. Group B used an ultrasonic bath with enzymatic cleaner and an autoclave. Group C used a prophy jet, enzymatic cleaner foam, and an autoclave. Group D used a prophy jet, an ultrasonic bath with enzymatic cleaner, and an autoclave. Lastly, group E used a prophy jet and an autoclave. The control group consisted of 10 new and sterile HAs. Residual protein concentration was determined by a Micro BCA protein assay (Thermo Fisher Scientific), while HAs from each group were stained with Phloxine B and macroscopically examined for the presence of debris. To examine the inflammatory potential, human primary macrophages were exposed to HAs, and supernatant levels of nine cytokine and chemokine profiles were analyzed using a multiplex bead assay. Results: All test groups showed differences in the degree of visual decontamination compared to controls. Groups D and E displayed the most effective surface debris removal and reduced protein concentration, while group A was the least effective. However, compared to controls, all test groups showed high levels of inflammatory cytokine secretion via multiplex assay for up to 5 days. Conclusions: Our study found that decontamination of uHAs utilizing enzymatic cleaners failed to reestablish inert HA surfaces and prevent an inflammatory immune response in vitro. Clinicians should not reuse HAs even after attempts to decontaminate and sterilize HA surfaces. [ABSTRACT FROM AUTHOR]

Surface contaminants on customized implant abutments could trigger an inflammatory response in the peri-implant tissues. The aim of this randomized controlled study was to assess the radiographic bone changes around implants restored with customized, platform-switched abutments, with and without autoclave treatment, 12 months after definitive restoration. Dental implants were placed 1 mm subcrestally in 64 systemically healthy patients (mean age: 63.3 ± 10.0 years; 31 patients had a history of periodontitis) to replace single or multiple missing teeth. According to a randomization list, abutments were subjected to steam and autoclave sterilization (43 implants, test group) or steam cleaning alone (44 implants, control group). Periapical standardized radiographs were taken at implant placement, prosthetic abutment connection, and 12 months after definitive cement-retained restoration. All implants were clinically stable without any sign of infection at the 12-month follow-up. An average marginal bone loss of 0.25 ± 0.19 mm was found in the test group compared to 0.35 ± 0.23 mm in the control group (no statistically significant difference), while the percentage of bleeding sites was significantly higher in the control group (8.7% ± 13.1% vs 19.1% ± 19.8%; P = .035). Autoclave treatment of customized abutments seems to reduce the inflammatory response around subcrestally placed implants. [ABSTRACT FROM AUTHOR]

Following implant placement, a soft tissue barrier will form at the healing abutment connection called peri-implant mucosa. The dimension of this anatomical structure seems to play a key role in maintaining long-term peri-implant and marginal bone level stability. In its early stages, soft tissue healing is a process involving many cellular and molecular events. Enamel matrix derivative (EMD) may improve and accelerate soft tissue wound healing and inflammatory resolution. In the present split-mouth randomized clinical trial, EMD was used to influence the early phase of soft tissue healing around dental implants placed with a single-stage approach into a completely healed ridge. A total of 60 implants were placed in 30 patients (2 implants per patient, one in the test group and one in the control group). In the test sites, EMD was administered around the healing abutment before soft tissues were sutured. Soft tissue healing index (HI) and secondary endpoints (clinical, radiographic, and patientreported outcomes) were measured. Better outcomes were recorded in patients receiving EMD for all parameters. The present results support the use of EMD to improve and accelerate soft tissue wound healing around implants. [ABSTRACT FROM AUTHOR]

Purpose: To assess the clinical concept of patient treatment with fixed tooth- and implant-supported restorations in a university-based undergraduate program after 13 to 15 years. Materials and Methods: In total, 30 patients (mean age 56 years) who had received multiple tooth- and implant-supported restorations were recalled after 13 to 15 years. The clinical assessment comprised biologic and technical parameters as well as patient satisfaction. Data were analyzed descriptively, and the 13- to 15-year survival rates for tooth- and implant-supported single crowns and fixed dental prostheses (FDPs) were calculated. Results: The survival rate of tooth-supported restorations amounted to 88.3% (single crowns) and 69.6% (FDPs); in implants, it reached 100% for all types of restorations. Overall, 92.4% of all restorations were free of technical complications. The most common technical complication was chipping of the veneering ceramic (tooth-supported restorations: 5.5%; implant-supported restorations: 13% to 15.9%) regardless of the material used. For tooth-supported restorations, increased probing depth = 5 mm was the most frequent biologic complication (22.8%), followed by endodontic complications of root canal-treated teeth (14%) and loss of vitality at abutment teeth (8.2%). Peri-implantitis was diagnosed in 10.2% of implants. Conclusions: The results of this study indicate that the clinical concept implemented in the undergraduate program and performed by undergraduate students works well. The clinical outcomes are similar to those reported in the literature. In general, the majority of biologic complications occur in reconstructed teeth, whereas implant-supported restorations are more prone to technical complications. [ABSTRACT FROM AUTHOR]

In our previous test model, the abutment teeth and the model base were printed with resin and bonded with a polyether material. Some abutment teeth were fractured during the mechanical load test. Therefore, the aim was to develop and evaluate a new model under mechanical loading until fracture with zirconia FPD frameworks. At a fracture load of up to 1,636 N, neither the artificial abutment teeth nor the base model fractured. Furthermore, the artificial abutment teeth did not detach from the base model. Therefore, the model should be suitable for mechanical testing of most ceramic-based framework materials for three-unit FPDs. [ABSTRACT FROM AUTHOR]

This document is a scientific study that examines the contamination levels on dental abutments and the effectiveness of a cleaning protocol. The study finds that custom-made abutments have surface pollutants, and laboratory procedures increase the amount of pollutants. However, the cleaning protocol tested is highly effective in cleaning both titanium and zirconia abutments. The study suggests that decontaminating abutments before placement may improve tissue integration. [Extracted from the article]

Purpose: The aims of the study were to evaluate the clinical performance and the complications of combined tooth-/implant-supported three-unit fixed partial dentures (FPDs) in the posterior mandible. Materials and Methods: A total of 78 partially edentulous patients in the posterior mandible were recruited for the study (n = 26/group). Group 1 served as the control group and received two dental implants to support a three-unit FPD. Groups 2 and 3 were the experimental groups in which one implant was placed in conjunction with support from an adjacent tooth to support a three-unit FPD. Standard implants (= 8 mm) were included in Group 2, while short implants (< 8 mm) were included in Group 3. Periapical radiographs were taken for evaluation of crestal bone loss (CBL). Modified plaque index (MPI), bleeding index (BI), and sulcus depth values of the abutment teeth were recorded at the time of FPD delivery, 6 months after FPD delivery, and annually thereafter. Recorded complications included abutment tooth intrusions, cementation failures of the restorations, porcelain chipping/delamination, framework fracture, abutment screw loosening, abutment and abutment screw fracture, and implant fracture. Results: Statistically significant differences were observed between Group 1 (0.06 ± 0.17) and Group 2 (0.18 ± 0.32) and between Group 1 and Group 3 (0.17 ± 0.30) in terms of MPI (P = .05). No difference was observed between Group 2 (0.11 ± 0.34) and Group 3 (0.14 ± 0.36) or between Group 1 (0.04 ± 0.22) and Group 2 in terms of BI. There were statistically significant differences in terms of CBL between Group 1 (0.259 ± 0.05 mm) and Group 3 (0.11 ± 0.03 mm) and between Group 2 (0.03 ± 0.03 mm) and Group 3 (P = .05). The mean abutment tooth sulcus depth was 1.11 ± 0.31 mm for Group 2 and 1.20 ± 0.46 mm for Group 3. Conclusions: Within the limitations of the current study, it was concluded that combined tooth/implant-supported prostheses (CTISPs) are a predictable treatment choice in the posterior mandible. When a CTISP is planned, it is more predictable to use a short implant than a standard-length implant. [ABSTRACT FROM AUTHOR]

Purpose: This prospective study evaluated the marginal bone level and periodontal parameters 6 years after placement of a convergent transmucosal neck implant. Materials and Methods: In total, 71 implants were placed in 60 patients. Of these, 52 implants were placed with a flapless technique and with the convergent neck exposed by 1 mm (early and delayed placement), while 19 implants were placed immediately after extraction (immediate placement). At least 3 months after insertion, customized abutments were applied and provisional resin crowns were cemented, while being careful to prevent any tissue compression. After 3 weeks, definitive metal-ceramic crowns were designed with the finish line at the soft tissue level and free from any compression. The implant survival rate at 6 years, marginal bone level changes (ΔMBL, mm), and Pink Esthetic Score (PES) were evaluated. Gingival phenotype was determined before the implant surgeries (thin/thick). A three-level hierarchical model was examined with a random intercept and random slope on follow-up time at the patient level and a random intercept at the implant level. Results: In all, 57 patients with 67 implants reached the 6-year point; 3 patients (5.0%) dropped out. The implant survival rate was 100%. ΔMBL from baseline to 24 months was 0.58 mm (95% CI: 0.48, 0.68), while ΔMBL from 24 to 72 months was 0.33 mm (95% CI: 0.19, 0.47). PES improved steadily from 6 to 48 months (+0.96; 95% CI: 0.71, 1.20), with overall stability at 72 months. No correlation between MBL and PES was observed. A significant association was found between thick gingival phenotype and less MBL variation. Greater implant diameter offered more MBL stability after 3 years but resulted in lower PES values. Conclusions: The use of convergent transmucosal neck implants placed with a flapless transmucosal approach with the crown margin positioned at the gingival level preserved marginal bone and guided gingival morphology for up to 72 months. The gingival phenotype was the parameter that most affected the soft and hard tissues. In the long term, implant placement timing was not related to MBL. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate and compare the difference in retention between implant-supported restorations with and without surface modification of the implant abutments. Materials and Methods: A total of 30 patients with singletooth implants were restored with cement-retained (Multilink N, Ivoclar) restorations using titanium base abutments (Variobase, Straumann) and randomly assigned surface modifications. Group 1 used nonmodified abutments, group 2 used sandblasted abutments, and group 3 used sandblasted abutments followed by an application of metal primer. All patients were recalled for a baseline examination 6 months after crown placement. The pull-out strength and intergroup distribution of mean pull-out strength were assessed. To assess differences between the three groups, intergroup statistical comparison of continuous variables was done using one-way ANOVA with Tukey correction for multiple group comparisons. Results: The results of the intergroup mean pull-out strength distribution revealed that the distribution of mean ± SD pull-out strength in group 1, group 2, and group 3 were 220.79 ± 94.23, 488.64 ± 84.12, and 705.46 ± 112.75 Ncm, respectively. Conclusions: Sandblasting followed by the application of metal primer produced the highest retention of porcelain-fused-to-metal (PFM) crowns to titanium base abutments, followed by sandblasting alone, with the least retention being observed with no surface treatment. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the effectiveness of coating of abutments with antimicrobial agents and their influence on the physicochemical and biologic properties of the coated materials. Materials and Methods: This work was registered in Open Science Framework (osf.io/6tkcp) and followed the PRISMA protocols. A search of two independent reviewers of articles published up to October 29, 2021, was performed in the Embase, PubMed, Science Direct, and Scopus databases. Results: The databases found a total of 1,474 references. After excluding the duplicates, 1,050 remained. After reading the titles and abstracts and applying the inclusion criteria, 13 articles remained and were read in full. A total of 8 articles were included in this systematic review. Different antimicrobial agents have been used to coat abutments, including graphene oxide, polydopamine, titanium and zirconium nitride, lactoferrin, tetracycline, silver, and doxycycline with varied release times. Titanium-coated silver showed a better antimicrobial agent release time of up to 28 days. Chemical analysis confirmed the presence of antimicrobials on the surface after coating. Different pathogenic microorganisms, such as Streptococcus sanguinis, Streptococcus oralis, and Staphylococcus aureus, were inhibited when in contact with the coated surface. Conclusions: This review showed that there is still no consensus on which is the better antimicrobial agent and which coated materials have the better performance. However, the association of surface coating of abutments with antimicrobials is feasible and can benefit many patients, which can support their clinical use to favor the healing process and prevent infections that can lead to treatment failure with dental implants. [ABSTRACT FROM AUTHOR]

The article discusses the results of a study which evaluated the effectiveness and accuracy of a proposed duplication technique in terms of one- and three-dimensional discrepancies between an original abutment and polyurethane duplicates obtained through a conventional workflow in single-implant rehabilitation. Topics covered include master cast with the Giroform System, abutment duplication and the influence of duplication on crown marginal and internal adaptation.

The article "Digital Technology: A Tool for the Treatment of Implant Reintervention" in Quintessence of Dental Technology discusses a case study of nonesthetic rehabilitation of a maxillary right central incisor with an implant. The use of digital planning tools facilitated safe and efficient interdisciplinary treatment involving cosmetic surgery and prosthetic rehabilitation. The article emphasizes the importance of proper planning and the use of digital tools to ensure predictable outcomes and simplify the treatment process. [Extracted from the article]

Purpose: To determine the characteristics of dental implant transmucosal surfaces that influence soft tissue attachment and marginal bone loss (MBL). Materials and Methods: The PubMed, Embase, and Cochrane Library electronic databases were searched based on predefined PICO eligibility criteria. Data from animal studies that compared junctional epithelium and connective tissue attachment and MBL from 4 days to 72 weeks were analyzed. The risk of bias was performed with the Systematic Review Centre for Laboratory Animal Experimentation tool. A rank analysis evaluation of data was performed, and the most frequently appearing materials/surfaces for each tissue compartment were identified. Results: The search identified 3,549 studies, 28 of which were eligible for analysis, with an average risk of bias of 28% ± 10%. Machined, polished, etched, sandblasted, or coated titanium and zirconia materials/surfaces were most frequently examined. Several studies investigated lithium disilicate, polyether ether ketone (PEEK) or polyether ketone ketone (PEKK), aluminum oxide, and gold. Based on ranking and frequency of use at different time points, titanium grade IV (Ti-4) microthreads with a polished neck area most frequently supported natural tooth-like junctional epithelial attachment (= 1.5 mm), while machined Ti-4 and machined titanium grade V (Ti-5) most frequently supported connective tissue attachment (= 1.25 mm) and led to the least MBL (= 0.75 mm). Conclusions: Analyzed data suggest that Ti-4 microthreads with a polished neck area and machined Ti-4 and Ti-5 were the materials/surfaces of choice for the transmucosal part of implants. However, the extensive heterogeneity in reported studies precludes solid identification of the best materials/surfaces. [ABSTRACT FROM AUTHOR]

Purpose: This in vitro study investigated the effect of implant geometry and diameter on the rotational load fatigue performance of an implant system with an internal conical connection with microthreads. Materials and Methods: Regular (4.2 mm) and wide-diameter (4.8 mm) Astra Tech EV implants with straight (S) and conical (C) geometries were tested with their corresponding titanium abutments, comprising four test groups: 4.2-mm S (Group 1), 4.2-mm C (Group 2), 4.8-mm S (Group 3), and 4.8-mm C (Group 4). Five samples were included in each group. Customized brass implant holders and abutment holders were machined. A rotational load fatigue machine was used to apply a sinusoidally varying load to the implant-abutment interface at an angle of 45 degrees to produce an effective bending moment of 35 Ncm at a frequency of 14 Hz (air temperature: 20°C). The number of cycles to failure was recorded, with the upper limit set at 5 × 106 cycles. Results were analyzed using ANOVA. Failed samples were examined with a scanning electron microscope to evaluate the mode of failure. Results: Of the 20 total samples, 2 failed, with Groups 1 and 2 each reporting one failure. Abutment and abutment screw fracture were observed in the failed sample in Group 1, while implant and abutment screw fracture occurred in the failed sample in Group 2. All wide-diameter implants ran beyond the cut-off without failure, but abutment screw loosening was noted in one sample in Group 3. No significant difference was found between implant groups of different geometries and diameters. Damage to the abutments and the implant internal surface were noted in all failed samples. Conclusions: While no significant differences were found between the test groups, failures were observed only in the regular-diameter group. The abutment and abutment screw fractured deep within the implant, and the implant fractured below the simulated bone level. These modes of failure may pose a significant clinical challenge during retrieval of these components. [ABSTRACT FROM AUTHOR]

This study retrospectively evaluated the influence of prosthetic features on marginal bone level changes around bone-level implants with an external hex connection. A total of 100 patients with 166 implants and cemented crowns were included. Demographic and clinical data were collected. Prosthetic features were radiographically evaluated, including emergence angle (EA), emergence profile (EP), crown-implant ratio (CIR), and abutment height. Marginal bone levels were measured on intraoral radiographs taken at baseline and after at least 1 year. The correlation between prosthetic features and marginal bone loss (MBL) was then investigated. The mean follow-up time was 43.94 months. Implant length varied between 5 and 13 mm. The mean height of the abutments used was 1.55 mm. EA measured an average 30.62 degrees (± 13.20) mesially and 29.45 degrees (± 13.07) distally. The CIR was 0.99 (± 0.26). The mean MBL was 0.19 mm on the mesial side and 0.20 mm on distal side of the implants. Significant positive associations emerged between MBL and implant length (P < .005) and with EA (P < .05). A convex profile of the crown was shown to be associated with a higher distal MBL (P = .025) compared to concave and str aight profiles. [ABSTRACT FROM AUTHOR]

Purpose: To assess two types of abutment materials routinely used in daily practice--direct polymethyl methacrylate (PMMA) and a zirconia-on--Ti-base abutment--and their effects on peri-implant soft tissues and bone remodeling in a minipig model. Materials and Methods: A total of 40 implants were placed in five minipigs in a single-stage surgery. Four different types of abutment materials (n = 10 per group) were used: (1) titanium (control); (2) zirconia (control); (3) PMMA (test 1); and (4) Ti-base (zirconia bonded to a titanium framework; test 2). After 3 months of healing, the samples were collected and subjected to nondecalcified histology. The soft tissue dimensions (sulcus, junctional epithelium, and connective tissue attachment) were assessed on each abutment mesially and distally, and the distance from the implant margin to the first boneto-implant contact (BIC) was measured. Results: No statistically significant differences were found among the four groups regarding soft tissue dimensions (P = .21), and a long junctional epithelium (mean: 4.1 mm) and a short connective tissue attachment (mean: 0.3 mm) were found in the majority of abutments. In some samples, the junctional epithelium extended all the way to the bone level. The measured peri-implant bone remodeling was similar in all four groups (P = .25). Conclusions: The present findings indicate that both direct PMMA and zirconia-on-Ti-base abutments seem to allow soft tissue integration similar to that of titanium and zirconia abutments. However, clinical studies are warranted to either confirm or refute the observed findings and to further investigate the influence of different materials on mucointegration. [ABSTRACT FROM AUTHOR]

Purpose: To examine the stresses caused by different All-on-4 surgical techniques—conventional, a combination of monocortical and bicortical, bicortical, and nasal floor elevation—on the implant and the surrounding bone using 3D finite element analysis (FEA). Materials and Methods: A 3D bone model of the atrophic maxilla was created based on CT imaging of the fully edentulous adult patient. All implants used in the models were 4 mm in diameter, and the length was 13 mm in the anterior and 15 mm in the posterior. Implants were applied to four different atrophic maxillary models with the All-on-4 technique: anterior and posterior monocortical implants in the first model, anterior monocortical and posterior bicortical in the second model, anterior and posterior bicortical in the third model, and anterior and posterior bicortical with nasal floor elevation in the fourth model. Eight linear analyses were performed by applying force from both vertical and 45-degree oblique directions to the four models prepared in our study. Results: When the cortical and cancellous bone around the anterior implants was examined, it was observed that the oblique and vertical loading conditions and the stresses around the implant were similar in all models. When the posterior implants were examined, model 1 (ie, anterior and posterior monocortical implants) showed the greatest oblique compression, vertical compression, and vertical tension forces. According to the Von Mises stress (VMS) analysis results for anterior and posterior implants, higher values were observed in model 1 compared to models 3 and 4 under oblique and vertical forces. It was observed that bicortical placement of the implants reduced the stresses on the bone and implant-abutment system but had no significant effect on the stress on the bar. Conclusions: According to the results of our study, in the All-on-4 technique, bicortical placement of the implants reduced the stresses on the bone and implant when the anatomical limitations allowed. In addition, nasal floor elevation can be applied in the atrophic maxilla in appropriate indications. [ABSTRACT FROM AUTHOR]

This retrospective study evaluated the survival rate and the clinical outcome of an endosseous implant system, as well as the marginal bone level (MBL) and the impact of the machined collar neck position on crestal bone level changes up to 2 years later. A total of 96 implants were placed in 57 patients and loaded with a final restoration after at least 3 months of healing: 15 implants were immediately placed into fresh extraction sockets, and 81 were placed in healed ridges. Marginal bone loss around implants was determined radiographically at 12 to 24 months postloading. The effects on marginal bone loss of the site (mandible vs maxilla), location (anterior vs posterior), immediate vs delayed implant, smoking habit, sex, implant length and diameter, prosthesis type (screw-retained/cemented), and the machined collar position were evaluated. The implant survival rate was 98.96% at 1 year. The mean MBL decreased significantly (0.238 mm) between baseline and loading (P < .001; post hoc test) and decreased by 0.154 mm between loading and 1 year, but this was not significant (P = .085; post hoc tests). After 2 years, the mean MBL decreased significantly (0.263 mm) between baseline and loading (P < .001) and decreased by 0.111 mm between loading and 1 year and by 0.199 mm between loading and 2 years, but these were not significant (P > .05; post hoc tests). The mean bone loss after 1 and 2 years was not significantly associated with implant type or site, smoking habit, or type of implant surgery (P = .792). However, the mean bone loss was significantly associated with the type of prosthesis and was significantly greater for cemented prostheses compared to screw-retained prostheses. A supracrestal position of the machined collar (tissue level) was associated with no bone loss, while placing the collar below the alveolar crest led to bone loss over 2 years. Of the factors evaluated, marginal bone loss after 1 and 2 years was significantly associated with prosthesis type and the machined collar position. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Materials and Methods Results Conclusion Physical and digital casts are required for fixed dental prosthesis (FDP) fabrication. However, the effect of abutment tooth geometry on the accuracy of FDP casts obtained by digital and analog workflows remains unclear. This study evaluated the accuracy of obtaining dental casts for veneer and full crowns with digital and analog workflows.A typodont model of the maxilla with unprepared teeth and veneer and full crown preparations was digitalized with intraoral scanning (TRIOS 3; 3Shape), digital model (DM) group, and the digital files were exported to two additive manufacturing technologies, resulting in the groups digital light processing (DLP) (Hunter; FlashForge) and polyjet (PLJ) (Eden 500 V; Stratasys). In addition, plaster casts (PCs) were obtained with polyvinyl siloxane (Express XT; 3M ESPE) double impressions and type IV plaster (FujiRock; GC America) as a control group. The sample size per group (n = 6) was defined in the pilot study. The digitization of the typodont and experimental casts was performed with a laboratory scanner (inEos X5; Dentsply Sirona). The measurement deviation (trueness and precision) to the reference model was performed with reverse engineering software (Geomagic Control X 2018; 3D Systems). Two‐way ANOVA was used to assess the effect of manufacturing techniques and abutment tooth geometry on model accuracy (primary outcome). In addition, one‐way ANOVA was used to assess significant differences between manufacturing techniques for complete arches, including abutments and unprepared teeth (secondary outcome). Tukey post hoc tests were used to compare means among groups. All statistical analyses considered a significant level of p ≤ 0.05.Statistically significant interactions were observed between manufacturing technique and abutment tooth geometry, affecting both trueness (p < 0.001) and precision (p < 0.001). For trueness, DM exhibited the lowest RMS values (p < 0.001), PC and DLP showed no significant difference (p = 0.056), and PLJ had significantly higher values than other techniques (p < 0.001), while premolar and molar preparations displayed significantly lower discrepancies compared to other types (p < 0.002). For precision, DM had the lowest values (p < 0.001), with PC also showing low values (p < 0.001), and no significant differences were observed between DLP and PLJ (p = 0.986). Veneer, premolar, and molar crown preparations demonstrated significantly lower RMS compared to anterior crowns.The design of the abutment tooth significantly influenced the trueness and precision of FDP casts obtained by digital and analog workflow. For trueness, DM exhibited the highest accuracy, outperforming PC, DLP, and PLJ and achieving better results with premolar and molar preparations compared to anterior crowns and veneers. For precision, DM was most accurate, followed by PC, DLP, and PLJ, with veneer, premolar, and molar crowns consistently outperforming anterior crowns. [ABSTRACT FROM AUTHOR]

Background: Digital technologies have not only revolutionized workflow strategies for implant- supported fixed prostheses but also changed preferences in the choice of restoration retention. Owing to the effortlessness of developing workflows with digitalization, screw-retention has become favored for initial prostheses. However, cement retention is still indicated for cases in which abutment reuse is needed for replacing failing restorations with technical complications. Case presentation: In this case report, a modified digital workflow is described for treating an impaired occlusal relationship. A dual-scan approach for an abutment-level digital implant impression to remake a cement retained implant supported fixed restoration is defined in detail. Conclusion: Clinicians can highly benefit from the presented strategy, which offers an efficient digital workflow to simplify cement-retained abutment level impressions through the use of an intraoral scanner. Exchanging intra- and extra-orally surface scanned abutment data may become an option in complete digital model-free workflows for addressing problems related to cement-retained implant supported fixed prostheses. [ABSTRACT FROM AUTHOR]

Objectives The main purpose of this study is to evaluate the efficacy of polyetheretherketone (PEEK) as a material for prefabricated crown restorations in pediatric dentistry, particularly for restoring primary tooth structure defects. Materials and methods This study analyzed the effects of three surface treatment modalities on PEEK's surface morphology, wettability (as measured by contact angle), and shear bond strength. These treatments included alumina (Al2O3) sandblasting alone, and in conjunction with a 98% sulfuric acid pretreatment. Subsequently, an evaluation was conducted to assess the compressive and fatigue properties of self-fabricated PEEK preformed crowns, preformed metal crowns, and preformed zirconia crowns. Results Al2O3 sandblasting followed by sulfuric acid pretreatment significantly enhanced the bond strength of PEEK. PEEK crowns, when compared with stainless steel and zirconia crowns, showed similar compressive and fatigue strengths to zirconia crowns but lower than metal alternatives. Additionally, PEEK crowns required less extensive modification of dental abutments compared to zirconia crowns. Conclusions The study concludes that PEEK prefabricated crown, especially after alumina (Al2O3) sandblasting in conjunction with a 98% sulfuric acid pretreatment, exhibits improved bond strength and favorable material characteristics for use in pediatric dental restorations. Clinical relevance The findings highlight the potential of PEEK prefabricated crowns in pediatric dentistry as a viable option for the aesthetic restoration of primary teeth, offering benefits over traditional materials like stainless steel and zirconia in terms of preferable compressive and fatigue strengths and ideal reduction of dental abutments. [ABSTRACT FROM AUTHOR]

ABSTRACT Background/Aim Materials and Methods Results Conclusion The fiber splint represents an advanced treatment for traumatized dental injuries. The complete understanding of the localization of a splint on traumatized teeth remains elusive. The aim of this study was to assess the impact of the incisal/cervical positions of the fiber splint on the stress distribution of traumatized dental roots in various occlusal relationships.Three‐dimensional finite element models were generated based on a cone beam computer tomogram of a patient. The incisal and cervical splints were simulated by strips that were bonded close to the incisal/cervical labial surface of traumatic teeth. Force was loaded on the incisal ridge, incisal and cervical positions on the palatal surface of each tooth to simulate the conditions of traumatized teeth during mastication. The equivalent stress (von Mises) on the traumatic teeth and abutment teeth was calculated by Ansys software (version 2021, R1).The incisal splint effectively transferred the stress from the traumatized tooth roots to the abutment teeth when force was loaded on the incisal ridge and incisal and cervical positions on the palatal surface. Nevertheless, the reduction effect was notably diminished when the cervical splint was used. Notably, in cases of cervical splints, with a loading force on the incisal ridge, there is an increase in stress on the roots of traumatized teeth, which poses a disadvantage in the management of traumatic dental injuries.The incisal splint demonstrated a more effective transfer of stress from the roots of the traumatic teeth to the abutment teeth than the cervical splint and the raw. [ABSTRACT FROM AUTHOR]

Implant treatment is provided to individuals with normal, idealized masticatory forces and also to patients with parafunctional habits such as grinding, clenching, and bruxing. Dental erosion is a common increasing condition and is reported to affect 32 % of adults, increasing with age. This oral environment is conducive to tribocorrosion and the potential loss of materials from the implant surfaces and interfaces with prosthetic components. Although several fretting-corrosion studies have been reported, until now, no study has simulated clinically relevant micromotion. Therefore, our aim is to investigate fretting-corrosion using our new micro-fretting corrosion system, simulating clinical conditions with 5 µm motion at the implant-abutment interface under various occlusal loads and acidic exposures. We simulated four conditions in an oral environment by varying the contact load (83 N and 233 N) and pH levels (3 and 6.5). The commonly used dental implant material, Grade IV titanium, and abutment material Zirconia (ZrO 2)/ Grade IV titanium were selected as testing couple materials. Artificial saliva was employed to represent an oral environment. In addition, a standard tribocorrosion protocol was followed, and the pin was controlled to oscillate on the disk with an amplitude of 5 μ m during the mastication stage. After the testing, 3D profilometry and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) were utilized to analyze the worn surfaces. Inductively coupled plasma mass spectrometry (ICP-MS) was also used to measure the metal ion release. Energy ratios were below 0.2, indicating a fretting regime of partial slip for all groups. Open-circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) were analyzed to compare the electrochemical behavior among groups. As a result, corrosive damage was observed to be more in the Ti4- Ti4 groups than in Zr-Ti4 ones, whereas more mechanical damage was found in the Zr-Ti4 groups than in the Ti4-Ti4 groups. Possible mechanisms were proposed in the discussion to explain these findings. The results observed from this study might be helpful to clinicians with implant selection. For example, for patients with bruxism, a titanium implant paired with a titanium abutment may be preferable, while patients with GERD may benefit more from a titanium implant paired with a zirconia abutment. [Display omitted] [ABSTRACT FROM AUTHOR]

Objectives: To compare early implant placement (EP) to alveolar ridge preservation and delayed implant placement (ARP/DP) in terms of contour changes, along with clinician‐ and patient‐reported outcome measures (PROMs) until the delivery of the implant‐supported restoration. Materials and Methods: Patients with a failing single tooth in the maxilla or mandible were recruited in two centres. After tooth extraction, patients were randomly assigned (1:1) to either EP or ARP/DP. At abutment connection and crown delivery, the buccal contour changes at 3 mm below the mucosal margin (primary outcome) along with clinician‐ (ease of treatment) and patient‐reported outcomes were assessed using numeric rating scales and OHIP‐14. Results: A total of 46 patients were analysed. The mean buccal contour at abutment connection decreased by −1.2 ± 0.6 mm in group EP and −1.6 ± 0.8 mm in group ARP/DP (estimated mean difference; 0.45 [95%CI, −0.02; 0.94]; p =.061) with no significant differences between the groups. ARP/DP was consistently easier than EP across all stages of the surgery (estimated mean difference; 2.0 [95%CI, 1.3; 2.7] p <.001): during flap elevation (EP: 4.8 vs. ARP/DP: 1.6), implant placement (EP: 5.7 vs. ARP/DP: 2.2) and wound closure (EP: 3.4 vs. ARP/DP: 1.6). Both interventions improved quality of life but patients who underwent ARP/DP were significantly more satisfied at the time of crown delivery (ARP/DP: 9.6 vs. EP: 9.1, p =.02). Conclusions: EP and ARP/DP show no significant differences in buccal contour changes, aesthetics and patient‐reported outcomes. However, ARP/DP is an easier procedure at all stages of the surgery compared to EP and could therefore be the preferred therapy for less experienced clinicians. [ABSTRACT FROM AUTHOR]

Purpose: To assess how well torque‐limiting devices (TLDs) are known and used by European dentists, and their adherence to screw tightening protocols and screw loosening occurrence through a survey, including the correlation between the dental specialty‐of‐interest and the recognition, the tightening protocol used, and between the calibration and the occurrence of screw loosening. Materials and methods: A 10‐question survey was distributed to dentists to collect data on their specialty‐of‐interest, TLD usage, knowledge on TLDs, calibration, the term "preload," tightening speed, tightening protocols used, and occurrence of screw loosening. Pearson test was used for correlation analysis between the specialty‐of‐interest and the recognition‐based questions, the tightening protocol used, and between the calibration and the frequency of screw loosening. Results: Of 422 respondents, 24% calibrated their TLDs, 27% knew the term "preload," 76% selected the correct location to read on TLDs, and 6% was aware of the effect of tightening speed. The correlation between the specialty‐of‐interest and the recognition‐based questions was nonsignificant (p <.05) but was significant for used tightening protocol (p <.001). The correlation between the calibration and the occurrence of screw loosening was nonsignificant (p = 0.16). Tightening protocols' effect on screw loosening was similar, which was mostly observed less than once a year (p <.001). Conclusions: A lack in dentists' knowledge was found on calibration, the term preload, and the effect of tightening speed, which were not impacted by the dentists' specialty‐of‐interest, which affected the preferred tightening protocol. The tightening protocol and calibration did not impact the occurrence of screw loosening, which was mostly observed less than once a year. [ABSTRACT FROM AUTHOR]

AbstractPurposeMethodsResultConclusionThe study aimed to investigate the mechanical effects of the taper position in the abutment hole and the screw taper angles on the implant system and peri-implant tissue using finite element analysis.Four taper positions (L1, L2, L3, L4) in the abutment hole were established using 3D software and five screw taper angles (30°, 60°, 90°, 120°, 180°) were set.Taper position significantly affects the stresses in the implant system. The 30° and 180° angles (L4 position) showed less stress than other angles.Elevated taper position and reasonable taper angle are beneficial in reducing the stress in the implant system. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives Materials and Methods Results Conclusion Clinical Significance This study compares the restoration of single‐tooth implants with screw‐retained lithium‐disilicate hybrid‐abutment crowns and single‐tooth lithium‐disilicate crowns adhesively bonded to hybrid abutments with regard to objective clinical and subjective patient‐specific evaluation criteria over a time of observation of 3 years.Two bone‐level implants were placed in contralateral sides of the same jaw in 10 patients, each with two single‐tooth gaps. After osseointegration, implants were uncovered and an impression was taken. In accordance with the split‐mouth design, one implant in each patient was restored with a screw‐retained hybrid abutment crown and the other implant with a hybrid abutment and an adhesively bonded single‐tooth crown. The restorations were randomly allocated to the implants. Prefabricated titanium bases were used. The ceramic abutments and restorations were fabricated monolithically with pressed lithium‐disilicate ceramic. An objective evaluation (survival, technical, or biological complications, FIPS) by the practitioner and a subjective evaluation (satisfaction, OHIP) by the patient were carried out after 3, 6, 12, 24, and 36 months after restoration placement.Both restoration types showed a survival rate of 100% after 3 years of observation. No technical or biological complications occurred. No significant difference was observed between the two types of restoration neither for objective (survival, technical or biological complications, FIPS) nor subjective (satisfaction, OHIP) evaluation criteria (p > 0.05).No statistically significant differences were observed between screw‐retained and cemented pressed lithium‐disilicate restorations on bone‐level implants for both objective and subjective evaluation criteria, respectively.Monolithic hybrid‐abutment crowns (screw‐retained) and monolithic hybrid abutments with single‐tooth crowns (cemented) made of pressed lithium disilicate can be used to successfully restore single implants. [ABSTRACT FROM AUTHOR]

Background: The current trial evaluated the midfacial gingival margin changes, volumetric, radiographic and clinical alterations 1-year following immediate implant placement with customized healing abutment (IIP + CHA) either solely, or in combination with xenograft (IIP + Bonegraft) or with connective tissue grafting (IIP + CTG) at sites with thin labial bone in the esthetic zone. Methods: Thirty-nine non-restorable maxillary teeth indicated for extraction in the esthetic zone were included. Participants were randomly assigned into three equal group; IIP + Bonegraft (Control), IIP + CTG and IIP + CHA. Midfacial gingival margin changes(mm) as primary outcome, labial soft tissue contour change(mm), interdental tissue height changes and total volume(mm3) were assessed. Amount of bone labial to the implant and crestal bone level changes were also recorded. All outcomes were measured 1-year post-operative. Results: The midfacial gingival margin changes demonstrated a significant difference (P ≤ 0.05) between the groups showing -0.98, -0.74 and -1.54 mm in sites treated with IIP + Bone graft, IIP + CTG and IIP + CHA respectively after1-year. While labial soft tissue contour change (mm), total volume (mm3) and distal interdental tissue height changes (mm) revealed a significant difference after one-year between the studied groups, yet mesial interdental tissue height changes showed no difference (P > 0.05). Both IIP + Bone graft and IIP + CHA groups revealed a significant positive correlation between the total volume loss (mm3) after 1 year and mid-facial gingival margin changes (P ≤ 0.05). However, no significant correlation was observed in the IIP + CTG group (P = 0.63). CBCT measurements showed a significant difference in crestal bone changes between the three groups (P ≤ 0.05), yet, there was no significant difference regarding mean amount of bone labial to the implant(P > 0.05). Conclusions: This investigation suggests that the mere presence of CTG simultaneous with IIP in the anterior maxilla reduced the midfacial gingival margin alterations (mm), besides, CTG decreased the overall volume loss (mm3) by 5-folds compared to the other studied groups after one year. Meanwhile, using CHA alone with IIP failed to maintain the peri-implant soft tissues contour. Trial registration: The current trial was retrospectively registered at Clinical trials.gov (ID: NCT05975515, Date: 27-July-2023). [ABSTRACT FROM AUTHOR]

Background: The passive fit of 3-unit implant supported prefabricated metal screw-retained prosthesis before implant placement might be difficult. Hence, we aim to evaluate the passive fit and time efficiency of CAD/CAM 3-unit implant supported fixed prostheses that were constructed based on virtual versus those based on actual implant positions in Kennedy Class I models. Methods: A sample of 5 Kennedy class I models with thin wiry ridges were restored by 20 frameworks bilaterally, 10 based on actual (group A) and 10 based on virtual (group V) implant positions. The models were imaged using cone beam computed tomography and scanned using an intraoral scanner. The STL (Standard Tessellation Language files) and the DICOM (Digital Imaging and Communications in Medicine) files were registered on a 3D planning software. A CAD/CAM surgical guide was planned, resin printed and used for installing 6 implants bilaterally. In group V, the framework was designed based on the virtual scan bodies and virtual multi-unit abutments, while in group A intra-oral scanning of the model after attaching the scan bodies was necessary. Frameworks of both groups were milled and tested for passive fit using 8 clinical tests. McNemar and Wilcoxon signed rank tests were used to study the effect of the group on passive fit and time efficiency, respectively. The significance level was set at P ≤ 0.05. Results: No statistically significant difference was found between group V and group A frameworks regarding passive fit (p-value = 1, OR = 0.5) and time efficiency (P = 0.179, Effect size = 0.948). Conclusion: Within the limitations of this study, it can be concluded that in free end saddle cases, prefabricated CAD\CAM 3-unit implant-supported cobalt chromium screw retained prostheses can achieve an adequate passive fit. However, their fit might be negatively affected in thin ridges and they might require some adjustments. [ABSTRACT FROM AUTHOR]

Background and Objectives: The aim of this study was to evaluate the influence of abutment angulation, types, and bone quality on fatigue performance in dental implant systems. Materials and Methods: Three-dimensional models of maxillary 3-unit fixed implant-supported prostheses were analyzed. Abutments with different angles and types were used. Healthy bone (Hb) and resorbed bone (Rb) were used. Conducted on implants, a force of 150 N was applied obliquely, directed from the palatal to the buccal aspect, at a specific angle of 30 degrees. The stress distribution and fatigue performance were then evaluated considering the types of bone used and the angles of the three different abutments. The simulation aspect of the research was carried out utilizing Abaqus 2020 software. Results: In all models, fatigue strengths in healthy bone were higher than in resorbed bone. Maximum stress levels were seen in models with angled implants. In almost all models with resorbed bone, fatigue performances were slightly lower. Conclusions: Increasing the abutment angle has been shown to increase stress levels and decrease fatigue performance in the adjacent bone and along the implant–abutment interface. In general, implants applied to healthy bone were found to have a higher success rate. It has also been suggested that multiunit abutments have beneficial effects on stress distribution and fatigue performance compared to resin cemented abutments. The type or angle of abutment and the quality of the bone can lead to biomechanical changes that affect the force distribution within the bone structure surrounding the implant. Clinicians can influence the biomechanical environment of the implant site by varying the abutment angle and type to suit the condition of bone health, potentially affecting the long-term success of implant treatment. [ABSTRACT FROM AUTHOR]

Objective: The aim of this investigation was to evaluate the effect on clinical and radiological outcomes of the one‐abutment, one‐time protocol (test) versus placing the definitive abutment on the day of functional loading after having disconnected and connected three times the healing abutment during the prosthetic phase (control). Materials and methods: Forty patients with 80 implants were randomly allocated to either the test or the control group. Changes in the radiographic marginal bone levels (MBLs), clinical outcomes, prosthetic‐related outcomes, and patient‐reported outcomes measures (PROMs) were assessed and compared 6 and 12 months after functional loading. Results: Thirty‐seven patients with 74 implants were followed at 12 months. A statistically significant bone remodeling was observed in both groups following implant placement. MBLs were significantly greater in the control group at the 6‐ (−0.13 mm vs. −0.61 mm) and 12‐month visits (−0.01 mm vs. −0.53 mm). Bone loss was significantly greater in the control group from surgery to 6 and 12 months and from loading to 6 and 12 months. The abutment height was significantly greater in the test group, however, there were no significant differences in the restorative angle. Similarly, there were no statistically significant differences between groups for the measured clinical variables (probing depth, plaque, and bleeding index) and PROMs. Conclusions: Disconnecting and reconnecting the healing abutment was associated with significantly higher bone loss after 12 months, as compared to the placement of the definitive abutment at implant installation. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of the deterioration of computer aided design/computer aided manufacturing (CAD/CAM) burs during zirconia milling, on surface roughness, contact angle, and fibroblast viability. Materials and Methods: Ceramic blocks were milled and 75 ceramic disks (8 × 1.5 mm) made and allocated into three groups (n = 25): G1‐brand new 2L and 1L burs, G2‐2L bur at the end of lifetime and brand new 1L bur and G3‐both burs at the end of their lifetimes. Roughness (Ra, Rq, and Rz) was evaluated using a 3D optical profilometer, the contact angle by the sessile drop method and the cell viability of the mouse NIH/3T3 fibroblast, using the Alamar Blue assay at intervals of 24, 48, and 72 h (ISO 10993‐5). Data were analyzed by one‐way ANOVA and Kruskal–Wallis tests (p ≤ 0.05). Results: Roughness increased as the burs deteriorated and G3 (0.27 ± 0.04) presented a higher value for Ra (p < 0.001). The highest contact angle was observed in G3 (86.2 ± 2.66) when compared with G1 (63.7 ± 12.49) and G2 (75.3 ± 6.36) (p < 0.001). Alamar Blue indicated an increase in cell proliferation, with no significant differences among the groups at 24 and 72 h (p > 0.05). Conclusions: The deterioration of the burs increased the surface roughness and decreased the wettability, but did not interfere in cell viability and proliferation. Clinical Significance: The use of custom zirconia abutments represents an effective strategy for single crowns restorations. Our findings suggest that these abutments can be efficiently milled using CAD/CAM burs within their recommended lifetime. [ABSTRACT FROM AUTHOR]

Objective: Dental implants placed in adolescent patients pose a challenge to restore and maintain an esthetic outcome over longer period of follow‐up. Maxillomandibular changes throughout adulthood may lead to complications such as implant infraocclusion and interproximal contact loss. This case report describes an alternate prosthetic treatment strategy for maxillary single implant placed in an adolescent patient in the esthetic zone with inappropriate implant axis and screw hole placement. Clinical considerations: With temporary restorations, the gingiva and soft tissues were shaped to imitate the emerging profile of the contralateral side. A zirconia screw‐retained abutment was customized as a copy‐mirror from the contralateral prepared tooth to mimic the exact shape and to avoid labiolingual over contour by computer‐aided design/computer‐assisted manufacture (CAD/CAM). The porcelain laminate veneer was bonded to the zirconia abutment. Porcelain adhesive approach was used instead of traditional principles of retention and resistance form of the abutment. Conclusions: A functional and esthetic outcome was achieved and maintained, while a minimally invasive procedure was implemented to use the malplaced implant instead of explanting it. Clinical significance: The present report illustrates the prosthetic management of a malpositioned dental implant placed 20 years ago, utilizing a minimally invasive digital protocol. [ABSTRACT FROM AUTHOR]

This is the first article in a three-part series that discusses joint orthodontic–restorative care for the adult patient. Part 1 presents an overview of the clinical presentations, challenges and strategies that may be employed to treat this complex patient group. CPD/Clinical Relevance: The reader should be able to describe a care pathway, with potential associated complications, for the provision of adult orthodontic–restorative treatment. [ABSTRACT FROM AUTHOR]

Copyright of Fogorvosi Szemle is the property of Hungarian Dental Association 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.)

Background: In edentulous jaws, factors such as the number of implants, cross-arch distribution, and the angle among implants may affect the accuracy of the implant impression. This study explored factors influencing the accuracy of implant abutment-level digital impressions using stereophotogrammetry in edentulous jaws. Methods: Two standard all-on-4 and all-on-6 models of edentulous jaws were constructed in vitro. In the stereophotogrammetry group (PG), the implant digital impression was made using stereophotogrammetry and saved as an STL file. In the conventional group (CNV), the impression was made using the open-tray splint impression technique. An electronic and optical 3D measuring instrument was used to scan the standard model and the conventional plaster model to obtain STL files. Using 3D data processing software (GOM Inspect Pro, Zeiss), the distance and angle between the abutments in the CNV impression and the PG impression were measured and compared with the data from the standard model. Results: The distance deviation in the PG and the CNV was 145 ± 196 μm and 96 ± 150 μm, respectively, with a significant difference (P < 0.001). The angle deviation in the PG and the CNV was 0.82 ± 0.88° and 0.74 ± 0.62°, respectively, with no significant difference (P = 0.267). In the PG, the distance deviation was negatively correlated with the distance between implants (r = -0.145, P = 0.028) and positively correlated with the angle of implants (r = 0.205, P = 0.002). The angle deviation was negatively correlated with the distance between implants (r = -0.198, P = 0.003) and positively correlated with the angle of implants (r = 0.172, P = 0.009). In the CNV, the effect of inter-implant distance on impression accuracy was also shown by Spearman correlation analysis: r = 0.347 (P < 0.001) for distance deviation and r = -0.012 (P = 0.859) for angle deviation. The effect of inter-implant angulation on impression accuracy deviation was r = -0.026 (P = 0.698) for distance deviation and r = 0.056 (P = 0.399) for angle deviation. Conclusions: The CNV method is closer to the real value of the original model. The distance between implants and the distribution angle had a weak correlation with the accuracy of digital impressions but no significant correlation with the accuracy of traditional impressions. [ABSTRACT FROM AUTHOR]

Objective: This study assessed the effect of the anodization of titanium abutments on the color parameters and color difference of lithium disilicate (LDS) all‐ceramic crowns. Materials and Methods: In this study, 19 straight abutments were divided into two groups: anodized (n = 9) and non‐anodized control (n = 9), with one hybrid zirconia abutment as a reference. Anodization was achieved by applying 63 V energy using seven 9 V flat batteries in series, with an electrolyte solution comprising 1 g trisodium phosphate in 250 mL distilled water for 5 s, resulting in a gold‐yellow color. Abutments were then scanned, and full‐contour monolithic IPS e.max maxillary central incisor crowns were fabricated with 2 mm thickness and glazed. Reflectance was measured using a spectroradiometer, and color coordinates (L*, a*, b*, h*, and C*) were calculated using CS‐10W software. Color differences of the crowns in both groups were quantified using the CIEDE2000 (ΔE00) color difference formula and analyzed by t‐test (α = 0.05) compared to the standard sample. Results: The L*, a*, b*, and c* parameters in anodized abutments were significantly higher than those in non‐anodized abutments, while the h* parameter in anodized abutments was significantly lower than that in non‐anodized abutments (p < 0.001 for all). There was a significant difference in ΔE00 of the two groups (p = 0.043). Conclusion: Anodization of titanium abutments improved the color parameters of LDS all‐ceramic crowns and significantly decreased their ΔE compared with non‐anodized abutments. Clinical Relevance: The research findings indicate that the anodization of titanium abutments significantly impacts color parameters, leading to lighter, redder, and more color‐saturated samples compared to non‐anodized ones. This suggests that anodization can optimize color matching in dental restorations, particularly in esthetic dentistry where precise color reproduction is crucial for natural‐looking results. Implementing anodization techniques may enhance the overall esthetic outcomes of dental prosthetics, providing clinicians with a valuable tool to improve patient satisfaction and confidence in their smiles. [ABSTRACT FROM AUTHOR]

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: To compare the fit of 3D-printed titanium (Ti) and cobalt-chromium (Co-Cr) abutments with implants to computer numerical control (CNC)-milled, ready-made abutment-implant assemblies. Their clinical applicability was also evaluated by measuring removal torque values (RTVs) and percentage torque loss of abutment screws. Materials and Methods: A total of 138 abutments were included in the study: 92 abutments were fabricated with Ti and Co-Cr alloys using computerassisted design (CAD) through selective laser melting, and 46 ready-made abutments were prepared. The fit of interfaces between 90 abutments from the three groups (30 ready-made, 30 3D-printed Ti, and 30 3D-printed Co-Cr abutments) and implant assemblies was demonstrated by scanning electron microscopy (SEM) and confocal scanning laser microscopy (CSLM). After 30-Ncm torque tightening of Ti abutment screws twice within 10 minutes, the RTVs and percentage torque loss of screws of 48 abutments (16 ready-made, 16 3D-printed Ti, and 16 3D-printed Co-Cr) were evaluated after 10 minutes of thermocycling and cyclic loading. Results: The fits of 3D-printed Co-Cr abutments were not statistically different from those of ready-made abutments (P = .383), while the fit of 3D-printed Ti abutments was inadequate (P < .001). The RTVs of 3D-printed abutments after cyclic loading were significantly decreased compared with those of CNC-milled abutments (P < .001). Conclusion: The fit of interfaces between 3D-printed Co-Cr abutments and implants was adequate. The RTVs of 3D-printed Co-Cr abutments were not significantly different from those of CNC-milled abutments after 10 minutes of 30-Ncm torque tightening and thermocycling. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the peri-implant outcomes of customized healing abutments (CstHA) placed on dental implants inserted in fresh tooth extraction sockets. Materials and Methods: The study was registered on PROSPERO: CRD42022304320. A systematic search in PubMed, Scopus, and Web of Science was conducted between April 2022 and October 2022 to identify clinical studies involving immediate implant surgery associated with CstHA placement. The Joanna Briggs Institute Critical Appraisal and RoB2 tool were performed for the risk of bias analysis. Results: A total of 12 studies were included, most of them with low risk of bias. Four studies compared CstHA vs conventional healing abutments (CnvtHA), two compared CstHA vs cover screw and collagen matrix (CMa), and six were clinical case series. For the CstHA vs CnvtHA comparison, favorable results were observed for CstHA considering papilla maintenance and probing depth, yet the mean marginal bone level was statistically similar between CstHA and CnvtHA. CstHA showed advantages when compared to CMa for total bone volume, papilla height, and midfacial mucosa maintenance. Significantly less horizonal bone loss was reported when using CstHA compared with CMa. Horizontal and vertical bone loss was observed in a few (or no) sites in the case series using CstHA. Conclusions: CstHA provides favorable peri-implant response because in general it does not result in a significant loss of soft and hard tissues. [ABSTRACT FROM AUTHOR]