Assessment of a novel electrochemically deposited smart bioactive trabecular coating (SBTC®): a randomized controlled clinical trial.

OBJECTIVES: A randomized controlled clinical trial of dental implants was conducted to compare the clinical properties of a novel electrochemically deposited calcium phosphate coating to those of a common marketed surface treatment. MATERIAL AND METHODS: Forty implants of the same brand and type were placed in 20 fully edentulous participants requiring mandibular implantation. The two study groups were defined by the surface treatment of the implants. 20 implants in the control group were coated via a commercial electrochemical surface treatment that forms a mixture of brushite and hydroxyapatite, while the remaining 20 in the test group were coated with a novel electrochemical Smart Bioactive Trabecular Coating (SBTC®). A split-mouth design was employed, with each participants receiving one control implant in one mandibular side and a test implant in the other. To mitigate potential operator-handedness bias, control and test implants were randomly assigned to mandibular sides. All cases underwent digital planning, implant placement with a static surgical guide, and participants received locator-anchored full-arch dentures. The primary outcome was implant stability (measured using Osstell ISQ) assessed at insertion, loading, and then 3 months, 9 months, and 2 years post-insertion. The secondary outcome was bone level change (in millimeters) over the 2-year observation period. Oral health-related quality of life (OHRQL) was monitored using the OHIP-14 questionnaire. Complications and adverse events were recorded. RESULTS: Successful osseointegration and implant stability were achieved in all cases, allowing loading. ISQ values steadily increased throughout the observation period. While no significant differences were observed between the SBTC® and control coatings, the test group exhibited a higher ISQ gain. Bone resorption was somewhat lower in the SBTC® but not significantly so. Patients' OHRQL significantly improved after denture delivery and remained stable throughout the follow-up. No complications or adverse events were observed. CONCLUSIONS: Based on the study results, we conclude that the new surface treatment is a safe alternative to the widely used control surface, demonstrating similar osseointegrative properties and time-dependent bone level changes. Further research may explore the broader implications of these findings. TRIAL REGISTRATION: The study is registered on clinicaltrials.gov under the identifier ID: NCT06034171.

Mechanical Performance of Extensive Restorations Made with Short Fiber-Reinforced Composites without Coverage: A Systematic Review of In Vitro Studies.

In recent years, composite resin materials have been the most frequently used materials for direct restorations of posterior teeth. These materials have some clinically relevant limitations due to their lack of fracture toughness, especially when used in larger cavities with high volume factors or when utilized as direct or indirect overlays or crown restorations. Recently, short-fiber-reinforced composite materials have been used in bi-structure restorations as a dentine substituting material due to their superior mechanical properties; however, there is no scientific consensus as to whether they can be used as full restorations. The aim of our review was to examine the available literature and gather scientific evidence on this matter. Two independent authors performed a thorough literature search using PubMed and ScienceDirect up until December 2023. This study followed the PRISMA guidelines, and the risk of bias was assessed using the QUIN tool. The authors selected in vitro studies that used short-fiber-reinforced composite materials as complete restorations, with a conventional composite material as a comparison group. Out of 2079 potentially relevant articles, 16 met our inclusion criteria. All of the included studies reported that the usage of short-fiber-reinforced composites improved the restoration's load-bearing capacity. Fifteen of the included publications examined the fracture pattern, and thirteen of them reported a more favorable fracture outcome for the short-fiber-reinforced group. Only one article reported a more favorable fracture pattern for the control group; however, the difference between groups was not significant. Within the limitations of this review, the evidence suggests that short-fiber-reinforced composites can be used effectively as complete restorations to reinforce structurally compromised teeth.

Evaluation of microhardness of short fiber-reinforced composites inside the root canal after different light curing methods - An in vitro study.

OBJECTIVES: Short fiber-reinforced composite (SFRC) materials make it possible to reinforce root canal treated teeth with individualized, directly layered intraradicular posts (the Bioblock technique). The question arises, however, as to whether the photopolymerization of the material is sufficient deep within the root canal space and if it can be improved through different light-conducting options. Our study aimed to investigate the hardness of intraradicular SFRC material applied using the Bioblock technique and cured with various illumination methods, as measured through nanoindentation. MATERIALS AND METHODS: For this investigation, thirty plastic artificial teeth that had undergone root canal treatment were selected. These teeth were randomly divided into six study groups (Group 1-6; each group consisting of 5 teeth). The restoration procedures involved the use of SFRC or conventional composite materials, placed 6 mm apically from the root canal orifice. In Group 1 and 2, a conventional composite was used, whereas in Group 3-6, SFRC was employed for interradicular reinforcement (with a layered technique in Group 3 and 4 and a bulk-fill technique in Group 5 and 6). A modified light source was utilized for photopolymerization in Group 2, 4, and 6, whereas in Group 3 and 5, the polymerization light was directed through a prefabricated glass fiber posts. The control group (Group 1) utilized conventional composite material with a standard light-curing method. Following embedding and sectioning, the hardness of the composite materials was measured at 2 mm intervals within the root canal (1st, 2nd, 3rd measurements, in the coronal to apical direction). RESULTS: During the 1st measurement, light curing conducted through the glass fiber posts (Group 3 and 5) led to markedly higher hardness levels compared to the groups restored with conventional composite (control group with p = 0.002, p = 0.001, and Group 2 with p = 0.043, p = 0.034, respectively). In the 2nd measurement, only Group 5 demonstrated significantly greater hardness in comparison to the control group (p = 0.003) and Group 2 (p = 0.015). However, in the 3rd measurement, no statistically significant differences were observed among the groups. CONCLUSION: light curing through the glass fiber post provides outstanding hardness for the SFRC material in the apical layer in the root canal.

Suboptimal multisensory processing in pediatric migraine without aura: a comparative, cross-sectional study.

Alterations of sensory processing in migraine are well known. There is some evidence to suggest that multisensory processing is altered in migraine as well, but the area is underexplored, especially regarding pediatric migraine. A visual and an audiovisual version of the Rutgers Acquired Equivalence Test paradigm was administered to pediatric patients with migraine without aura (aged 7-17.5 years) and to age- and sex-matched controls. The application of audiovisual stimuli significantly facilitated associative pair learning in migraine-free children and adolescents, but not in pediatric migraine patients. The results of this study corroborate the hypothesis that multisensory processing is altered in pediatric migraine without aura.

Factors Influencing Patient Satisfaction and Loyalty as Perceived by Dentists and Their Patients.

OBJECTIVE: This study aimed to identify the key aspects of patients' dental care experience that influenced their self-perceived satisfaction and loyalty. Also examined was the agreement between patients and dentists regarding these factors. METHODS: Questionnaires were administered to 1121 patients and 77 dentists, focusing on demographic information and 15 selected items related to the patients' last dental visit. Descriptive and linear regression analyses were conducted. RESULTS: The study included participants from 41 practices. Factors significantly influencing satisfaction and loyalty included location convenience, treatment quality, trust in dentists' decisions, visit frequency satisfaction, clear treatment explanations, dentist's interest in symptoms, patient-dental personnel attachment, and dentist's knowledge of the patient and their medical records. While overall agreement between patients and dentists was high, some areas exhibited notable disagreement. CONCLUSIONS: The findings mostly align with existing literature, underscoring the importance of communication, trust, and a personal patient-dentist relationship in promoting satisfaction and loyalty. However, they also show that local, generally not reported factors might be at play, which necessitates dentists' awareness and consideration of the local context for optimal outcomes.

Oral Health of Patients Undergoing Percutaneous Coronary Intervention-A Possible Link between Periodontal Disease and In-Stent Restenosis.

Introduction: There is a well-documented association between coronary artery disease (CHD) and periodontal disease (PD) mediated by common inflammatory pathways. This association, however, has not been investigated extensively in the special context of in-stent restenosis. This study aimed to investigate the periodontal status of patients undergoing percutaneous coronary intervention (PCI) for restenotic lesions. Methods and Results: We enrolled 90 patients undergoing percutaneous coronary intervention and 90 age- and gender-matched healthy controls in the present study. All subjects received a full-mouth examination by a periodontist. Plaque index, periodontal status, and tooth loss were determined. The periodontal state was significantly worse (p < 0.0001) in the PCI group, and each periodontal stage increased the odds of belonging to the PCI group. This effect of PD was independent of diabetes mellitus, another strong risk factor for CAD. The PCI group was further divided into two subgroups: PCI for restenotic lesions (n = 39) and PCI for de novo lesions (n = 51). Baseline clinical and procedural characteristics were comparable between the two PCI subgroups. A significant (p < 0.001) association was found between the PCI subgroup and the severity of periodontal disease, with the incidence of severe PD reaching 64.1%. Conclusions: Patients undergoing PCI for in-stent restenosis exhibit more severe forms of periodontal disease not only as compared to healthy controls but also as compared to patients stented for de novo lesions. The potential causality between PD and restenosis must be studied in larger prospective studies.

Fatigue performance of endodontically treated molars reinforced with different fiber systems.

OBJECTIVE: The aim was to investigate the fatigue performance of root canal-treated (RCT) molars restored with different direct restorations utilizing discontinuous and continuous fiber-reinforced composite (FRC) systems. The impact of direct cuspal coverage was also evaluated. MATERIALS AND METHODS: One hundred and twenty intact third molars extracted for periodontal or orthodontic reasons were randomly divided into six groups (n=20). Standardized MOD, regular cavities for direct restorations were prepared in all specimens, and subsequently, root canal treatment and root canal obturation was carried out. After the endodontic treatment, the cavities were restored with different fiber-reinforced direct restorations as follows: SFC group (control), discontinuous short fiber-reinforced composite (SFC) without cuspal coverage (CC); SFC+CC group, SFC with cuspal coverage; PFRC group, transcoronal fixation with continuous polyethylene fibers without CC; PFRC+CC group, transcoronal fixation with continuous polyethylene fibers with CC; GFRC group, continuous glass FRC post without CC; and GFRC+CC, continuous glass FRC post with CC. All specimens underwent a fatigue survival test in a cyclic loading machine until fracture occurred or 40,000 cycles were completed. The Kaplan-Meier survival analysis was conducted, followed by pairwise log-rank post hoc comparisons between the individual groups (Mantel-Cox). RESULTS: The PFRC+CC group was characterized by significantly higher survival compared to all the groups (p < 0.05), except for the control group (p = 0.317). In contrast, the GFRC group showed significantly lower survival compared to all the groups (p < 0.05), except for the SFC+CC group (p = 0.118). The control group (SFC) showed statistically higher survival than the SFRC+CC group (p < 0.05) and GFRC group (p < 0.05), but it did not differ significantly from the rest of the groups in terms of survival. CONCLUSIONS: Direct restorations utilizing continuous FRC systems (in the form of polyethylene fibers or FRC post) to restore RCT molar MOD cavities performed better in terms of fatigue resistance when CC was performed compared to the same FRC restorations without CC. On the contrary, teeth restored with SFC restorations performed better without CC compared to the ones where SFC was covered. CLINICAL RELEVANCE: In the case of fiber-reinforced direct restorations for MOD cavities in RCT molars, direct CC is recommended when utilizing long continuous fibers for reinforcement, however, should be avoided when only SFC is used for their reinforcement.

Fatigue Resistance of Dissected Lower First Molars Restored with Direct Fiber-Reinforced Bridges-An In Vitro Pilot Study.

The aim of this research was to evaluate the mechanical impact of utilizing different fiber-reinforced composite (FRC) systems to reinforce inlay-retained bridges in dissected lower molars with different levels of periodontal support. A total of 24 lower first molars and 24 lower second premolars were included in this study. The distal canal of all molars received endodontic treatment. After root canal treatment, the teeth were dissected, and only the distal halves were kept. Standardized class II occluso-distal (OD) (premolars) and mesio-occlusal (MO) (dissected molars) cavities were prepared in all teeth, and premolar-molar units were created. The units were randomly distributed among four groups (n = six/group). With the aid of a transparent silicone index, direct inlay-retained composite bridges were fabricated. In Groups 1 and 2, both discontinuous (everX Flow) and continuous (everStick C&B) fibers were used for reinforcement, while in Groups 3 and 4, only discontinuous fibers (everX Flow) were used. The restored units were embedded in methacrylate resin, simulating either physiological periodontal conditions or furcation involvement. Subsequently, all units underwent fatigue survival testing in a cyclic loading machine until fracture, or a total of 40,000 cycles. Kaplan-Meyer survival analyses were conducted, followed by pairwise log-rank post hoc comparisons. Fracture patterns were evaluated visually and with scanning electron microscopy. In terms of survival, Group 2 performed significantly better than Groups 3 and 4 (p < 0.05), while there was no significant difference between the other groups. In the case of impaired periodontal support, a combination of both continuous and discontinuous short FRC systems increased the fatigue resistance of direct inlay-retained composite bridges compared to bridges that only contained short fibers. Such a difference was not found in the case of sound periodontal support between the two different bridges.

Crack propensity of different direct restorative procedures in deep MOD cavities.

OBJECTIVE: The purpose was to evaluate the crack formation associated with different direct restorative procedures of the utilized resin composites (RC) right after and 1 week later of the restoration. MATERIALS AND METHODS: Eighty intact, crack-free third molars with standard MOD cavities were included in this in vitro study and randomly divided into four groups of 20 each. After adhesive treatment, the cavities were restored either with bulk (group 1) or layered (group 2) short-fiber-reinforced resin composites (SFRC); bulk-fill RC (group 3); and layered conventional RC (control). Right after the polymerization and a week later, crack evaluation on the outer surface of the remaining cavity walls was performed with a transillumination method utilizing the D-Light Pro (GC Europe) with the "detection mode." Between- and within-groups comparisons Kruskal-Wallis and Wilcoxon tests were used, respectively. RESULTS: Post-polymerization crack evaluation showed significantly lower crack formation in SFRC groups compared to the control (p<0.001). There was no significant difference within SFRC groups and non-SFRC groups (p=1.00 and p=0.11, respectively). Within group comparison revealed significantly higher number of cracks in all groups after 1 week (p≤0.001), however, only the control group differed significantly from all the other groups (p≤0.003). CONCLUSIONS: Post-polymerization shrinkage induced further crack formation in the tooth 1 week after the restoration. SFRC was less prone to shrinkage-related crack formation during the restorative procedure; however, after 1 week, besides SFRC, bulk-fill RC also showed less prone to polymerization shrinkage-related crack formation than layered composite fillings. CLINICAL RELEVANCE: SRFC can decrease the shrinkage stress-induced crack formation in MOD cavities.

Visual consequent stimulus complexity affects performance in audiovisual associative learning.

In associative learning (AL), cues and/or outcome events are coupled together. AL is typically tested in visual learning paradigms. Recently, our group developed various AL tests based on the Rutgers Acquired Equivalence Test (RAET), both visual and audiovisual, keeping the structure and logic of RAET but with different stimuli. In this study, 55 volunteers were tested in two of our audiovisual tests, SoundFace (SF) and SoundPolygon (SP). The antecedent stimuli in both tests are sounds, and the consequent stimuli are images. The consequents in SF are cartoon faces, while in SP, they are simple geometric shapes. The aim was to test how the complexity of the applied consequent stimuli influences performance regarding the various aspects of learning the tests assess (stimulus pair learning, retrieval, and generalization of the previously learned associations to new but predictable stimulus pairs). In SP, behavioral performance was significantly poorer than in SF, and the reaction times were significantly longer, for all phases of the test. The results suggest that audiovisual associative learning is significantly influenced by the complexity of the consequent stimuli.

Fracture Resistance and Microleakage around Direct Restorations in High C-Factor Cavities.

The aim of this research was to evaluate the mechanical impact of different direct restorations in terms of fracture resistance, and subsequent fracture pattern, in occlusal high C-factor cavities. Furthermore, the adaptation of different direct restorations in the form of gap formation was also evaluated. Seventy-two intact mandibular molars were collected and randomly distributed into three groups (n = 24). Class I occlusal cavities with standardized dimensions were prepared in all specimens. After adhesive treatment, the cavities were restored with direct restorations utilizing three different materials. Group 1: layered conventional packable resin composite (Filtek Ultimate), Group 2: bulk-fill resin composite (SDR), Group 3: bulk-fill short fibre-reinforced composite (SFRC; everX Posterior) covered with packable composite occlusally. Half of the restored specimens underwent static load-to fracture testing (n = 12/group), while the rest underwent sectioning and staining for microleakage evaluation and gap formation analysis. Fracture patterns were evaluated visually among the mechanically tested specimens. The layered composite restoration (Group 1) showed significantly lower fracture resistance compared to the bulk fill groups (Group 2, p = 0.005, Group 3, p = 0.008), while there was no difference in fracture resistance between the other groups. In terms of gap formation values, the layered composite restoration (Group 1) produced significantly higher gap formation compared to the bulk-fill groups (Group 2, p = 0.000, Group 3, p = 0.000). Regarding the fracture pattern, SFRC (Group 3) produced the highest number, while SDR (Group 2) produced the lowest number of repairable fractures. The use of bulk-fill resin composite (fibre or non-fibre-reinforced) for occlusal direct restorations in high C-factor cavities showed promising achievements regarding both fracture resistance and microleakage. Furthermore, the use of short fibre-reinforced bulk-fill composite can also improve the fracture pattern of the restoration-tooth unit. Bulk-fill materials provide a simple and effective solution for restoring and reinforcing high C-factor occlusal cavities.

Aerosol Reduction of 2 Dental Extraoral Scavenger Devices In Vitro.

OBJECTIVE: Since the outbreak of SARS-CoV-2, aerosol control in the operatory has become a key safety issue in dentistry. The utilisation of extraoral scavenger devices (EOSs) is one of the various approaches to in-treatment aerosol reduction in dentistry. The use and efficacy of EOSs in dental settings, however, are still a matter of debate in the literature and there are still open questions about their proper use. Thus, research into this area is essential to inform dental practice. The objective of this study was to examine the aerosol reduction efficacy of two different EOS in vitro. METHODS: Two commercially available EOSs were tested during modeled dental treatment in a setup that previously proved to generate high aerosol load. Measurements were done in two particle size ranges: 5.6-560 nm (the full range of the spectrometer) and 60.4-392.4 nm (a range that is especially relevant to the spread of SARS-CoV-2 with aerosol). RESULTS: Both devices managed to reduce the aerosol load to a statistically significant extent as compared to the scenario when only a high-volume evacuator and a saliva ejector (and no EOS) were used. CONCLUSIONS: Within the limitations of the study, the results support the assumption that EOSs for aerosol reduction increase in-treatment safety in the dental operatory.

Multisensory stimuli enhance the effectiveness of equivalence learning in healthy children and adolescents.

It has been demonstrated earlier in healthy adult volunteers that visually and multisensory (audiovisual) guided equivalence learning are similarly effective. Thus, these processes seem to be independent of stimulus modality. The question arises as to whether this phenomenon can be observed also healthy children and adolescents. To assess this, visual and audiovisual equivalence learning was tested in 157 healthy participants younger than 18 years of age, in both a visual and an audiovisual paradigm consisting of acquisition, retrieval and generalization phases. Performance during the acquisition phase (building of associations), was significantly better in the multisensory paradigm, but there was no difference between the reaction times (RTs). Performance during the retrieval phase (where the previously learned associations are tested) was also significantly better in the multisensory paradigm, and RTs were significantly shorter. On the other hand, transfer (generalization) performance (where hitherto not learned but predictable associations are tested) was not significantly enhanced in the multisensory paradigm, while RTs were somewhat shorter. Linear regression analysis revealed that all the studied psychophysical parameters in both paradigms showed significant correlation with the age of the participants. Audiovisual stimulation enhanced acquisition and retrieval as compared to visual stimulation only, regardless of whether the subjects were above or below 12 years of age. Our results demonstrate that multisensory stimuli significantly enhance association learning and retrieval in the context of sensory guided equivalence learning in healthy children and adolescents. However, the audiovisual gain was significantly higher in the cohort below 12 years of age, which suggests that audiovisually guided equivalence learning is still in development in childhood.

Mechanical Performance of Direct Restorative Techniques Utilizing Long Fibers for "Horizontal Splinting" to Reinforce Deep MOD Cavities-An Updated Literature Review.

Excessive cavity preparation and root canal treatment leads to a weakened tooth structure with a lower resistance to fracture. Fiber reinforcement is frequently used to reinforce such teeth, and multiple fiber types and possible applications exist. Various methods for utilizing long fibers to internally splint the remaining cavity walls in the case of large mesio-occluso-distal (MOD) cavities have been proposed; however, no summary of their performance has been written up to now. Our study aims to review the available literature to evaluate and compare the mechanical performance of the different materials and methods utilized for horizontal splinting in large MOD cavities. Three independent authors performed a thorough literature search using PubMed, ScienceDirect, and Google Scholar up until January 2022. The authors selected in vitro studies that used long fibers placed horizontally in posterior teeth with large MOD cavities to reinforce these teeth. From 1683 potentially relevant articles, 11 publications met our inclusion criteria. Seven out of eleven studies showed that horizontal splinting with long fibers improved the fracture resistance of the restored teeth. Three articles showed no significant difference between the fracture resistance of the restored groups. Only one article reported a lower fracture resistance to the horizontally splinted group, compared to conventional direct composite restoration. Within the limitations of this review, evidence suggests that long fiber reinforcement could be used to improve the fracture resistance of heavily restored teeth.

Fatigue performance of endodontically treated molars restored with different dentin replacement materials.

OBJECTIVES: The aim was to investigate the fatigue performance of endodontically treated (ET) molars restored by various dentin-replacing materials and material configurations. Moreover, the impact of additional adhesive treatment with glass-ionomer cement (GIC) was evaluated. METHODS: 250 intact molars were collected and randomly distributed into ten groups (n = 25). After endodontic procedure standard Class I cavities were prepared and restored with different direct restorative techniques and dentin-replacing materials. Two-group were restored with either packable or flowable short fiber-reinforced composites (SFRCs). Two-group were restored by experimental fiber-reinforced GIC with and without adhesive treatment. Four-group were restored by conventional and resin-modified GICs with or without adhesive treatment. One-group was restored with a dual-cure composite resin and last group was restored with only conventional composite resin (control). Fatigue-survival was measured for all specimens using a cyclic-loading machine until fracture occurred or a number of 40.000 cycles were achieved. Kaplan-Meyer survival analysis was conducted, followed by pairwise log-rank post hoc comparisons. Fracture mode was then examined by means of optical microscopy and SEM. RESULTS: Group restored with flowable SFRC showed significantly higher survival (p < 0.05) compared to all of the groups, except for group restored with packable SFRC (p > 0.05). Group restored with fiber-reinforced GIC had significantly (p < 0.05) higher survival rates compared to other commercial GICs. SEM demonstrated change of the fracture line when fracture reached the SFRC layer. SIGNIFICANCE: Direct restoration of Class I in ET molars with the use of SFRCs as dentin-replacing materials demonstrated its ability to reinforce the dental structures and to increase the fatigue resistance in this specific clinical situation.

The biomechanical effect of root amputation and degree of furcation involvement on intracoronally splinted upper molar teeth - An in vitro study.

OBJECTIVES: The aim of this study was to evaluate the effect of the amount of periodontal support and the presence or absence of root amputation on the fracture resistance of intracoronally splinted maxillary molar teeth. MATERIALS AND METHODS: 48 extracted human upper first molars and 48 s premolars were included in the study. All teeth underwent standard mesio-occluso-distal (MOD) (molars) and standard occluso-distal (OD) (premolars) cavity preparation. After the preparation, all molars were root canal treated, and 48 molar-premolar units were created by intracoronal splinting. The units were randomly divided into 4 groups (Groups A-D, 12 units per group): in Groups C and D, the disto-buccal (DB) roots of the molars were amputated, while in Groups A and B, no root amputation was performed. All units were embedded in methacrylate resin at different levels: in Groups A and C, at 4 mm apically from the cemento-enamel junction (CEJ), while in Groups B and D, at 6 mm apically from the CEJ, mimicking the different stages of furcation involvement. All units were submitted first to dynamic and then to static, load-to-fracture mechanical testing. Fracture resistance values were recorded fracture mode was analysed. RESULTS: During the load-to-facture test, Groups A and B (without root amputation) were characterized by significantly higher fracture resistance values compared to Groups C and D (with root amputation) (p < 0.05). Regarding fracture mode, irreparable fracture was more frequent in Group D (with root amputation and advanced furcation involvement) than in any other group (n = 8). CONCLUSIONS: Root amputation has a negative effect on the fracture resistance of intracoronally splinted upper first molar-second premolar units with modeled furcation involvement.

Fatigue performance of endodontically treated premolars restored with direct and indirect cuspal coverage restorations utilizing fiber-reinforced cores.

OBJECTIVES: The aim of this in vitro study was to investigate the fatigue survival and fracture behavior of endodontically treated (ET) premolars restored with different types of post-core and cuspal coverage restorations. MATERIALS AND METHODS: MOD cavities were prepared on 108 extracted maxillary premolars. During the endodontic treatment, all teeth were instrumented with rotary files (ProTaper Universal) to the same apical enlargement (F2) and were obturated with a matched single cone obturation. After the endodontic procedure, the cavities were restored with different post-core and overlay restorations (n = 12/group). Three groups (A1-A3) were restored with either conventional composite core (PFC; control) or flowable short-fiber-reinforced composite (SFRC) core with/without custom-made fiber posts and without overlays. Six groups had similar post-core foundations as described above but with either direct PFC (B1-B3) or indirect CAD/CAM (C1-C3) overlays. Fatigue survival was tested for all restorations using a cyclic loading machine until fracture occurred or 50,000 cycles were completed. Kaplan-Meyer survival analysis was conducted, followed by pairwise post hoc comparisons. RESULTS: None of the restored teeth survived all 50,000. Application of flowable SFRC as luting-core material with fiber post and CAD/CAD overlays (Group C3) showed superior performance regarding fatigue survival (p < 0.05) to all the other groups. Flowable SFRC with fiber post and direct overlay (Group B3) showed superior survival compared to all other direct techniques (p < 0.05), except for the same post-core foundation but without cuspal coverage (Group A3). CONCLUSIONS: Custom-made fiber post and SFRC as post luting core material with or without cuspal coverage performed well in terms of fatigue resistance and survival when used for the restoration of ET premolars. CLINICAL RELEVANCE: The fatigue survival of direct and indirect cuspal coverage restorations in ET MOD premolars is highly dependent on whether the core build-up is fiber-reinforced or not. The combination of short and long fibers in the form of individualized post-cores seems to offer a favorable solution in this situation.

Accuracy of digitally planned, guided apicoectomy with a conventional trephine and a custom-made endodontic trephine: An in vitro comparative study.

PURPOSE: Static guided trephine apicoectomy has been developed as a less invasive and more accurate alternative to conventional freehand apicoectomy with drills. Overpenetration is a frequent issue with this procedure, which deteriorates accuracy and raises safety concerns. A safety improvement to address this problem is presented. MATERIALS AND METHODS: Guided apicoectomies were performed in porcine mandibles with either a conventional bone trephine or a custom-made endo-trephine with built-in depth control. The deviation of the apical endpoint of the trephine from the digital surgical plan was analyzed. Overpenetration frequency was recorded. RESULTS: Procedures performed with the custom trephine were significantly more accurate both along the x-axis and globally, but no significant difference was found for the y and z axes. Overpenetration frequency was 70% in the conventional trephine group versus 38% in the stop trephine group. CONCLUSION: The results indicate that the lack of physical depth control can interfere with the accuracy (and safety) of these procedures to a significant extent, as visual cues (such as the depth markings on a conventional trephine) are insufficient to prevent overpenetration. Our results show that custom-made trephines with a built-in stop offer an optimal solution for this problem.

Accuracy of half-guided implant placement with machine-driven or manual insertion: a prospective, randomized clinical study.

OBJECTIVES: To compare the accuracy of implant placement performed with either a surgical motor or a torque wrench as part of a half-guided surgical protocol. MATERIALS AND METHODS: Implant insertion with half-guided surgical protocol was utilized by surgical motor (machine-driven group) or torque wrench (manual group) in the posterior maxilla. After the healing period, accuracy comparison between planned and actual implant positions was performed based on preoperative cone beam computed tomography and postoperative digital intraoral scans. Coronal, apical, and angular deviations, insertion time, and insertion torque were evaluated. RESULTS: Forty patients were treated with 1 implant each; 20 implants were inserted with a surgical motor and 20 implants with a torque wrench. Global coronal and apical deviations were 1.20 ± 0.46 mm and 1.45 ± 0.79 mm in the machine-driven group, and 1.13 ± 0.38 mm and 1.18 ± 0.28 mm in the manual group (respectively). The mean angular deviation was 4.82 ± 2.07° in the machine-driven group and 4.11 ± 1.63° in the manual group. Mean insertion torque was 21.75 ± 9.75 Ncm in the machine-driven group, compared to 18.75 ± 7.05 Ncm in the manual group. Implant placement duration was 9.25 ± 1.86 s in the machine-driven group at a speed of 50 rpm, and 36.40 ± 8.15 s in the manual group. CONCLUSION: No significant difference was found between the two groups in terms of accuracy and mean insertion torque, while machine-driven implant placement was significantly less time-consuming. CLINICAL RELEVANCE: Optimal implant placement accuracy utilized by half-guided surgical protocol can be achieved with both machine-driven and torque wrench insertion. TRIAL REGISTRATION: ID: NCT04854239.

Fracture Behavior and Integrity of Different Direct Restorative Materials to Restore Noncarious Cervical Lesions.

The purpose of this study was to analyze the fracture resistance and marginal leakage of noncarious cervical lesion (NCCL) restorations made of different restorative materials. Eighty upper premolars were randomly divided into four groups (n = 20/group). Standardized NCCL cavity preparations were performed on the buccal surface of the teeth and then restored with four different materials. Group 1: Packable resin composite (PC); Group 2: Highly flowable resin composite (HF); Group 3: Low flowable resin composite (LF); Group 4: Resin modified glass ionomer cement (RMGIC). After restorations were completed, cyclic and static fracture behavior was evaluated using a loading testing machine. Extra restored teeth were sectioned and then stained (n = 5/group). The specimens were viewed under a stereo microscope and the percentage of microgaps at the tooth-restoration interface was calculated. All restored teeth survived after fatigue loading. There was no statistically significant (p > 0.05) difference between the tested restorations after the static loading test. NCCLs restored with highly filled flowable composite showed the least microleakage among the tested groups (p < 0.05). The investigated restorative materials are acceptable for NCCL restorations in terms of fracture resistance and microleakage.