O emprego da moldagem digital na prática odontológica - relato de caso / The use of digital molding in dental practice ­ case report

O avanço da tecnologia de digitalização de imagens e desenvolvimento de dispositivos de fresagem possibilitaram a otimização de diversos processos na Odontologia. O emprego do escaneamento intraoral e do sistema CAD-CAM (CAD - Computer Aided Design; CAM - Computer Aided Manufacturing) aprimorou a realização de reabilitações protéticas, permitindo a obtenção de peças de alta qualidade em tempo reduzido. O objetivo deste trabalho é relatar um caso de reabilitação de um incisivo central inferior a partir de escaneamento intraoral, com scanner Omnicam (DentsplySirona Charlotte, NC, EUA) e aplicação do sistema CAD-CAM.

The advancement of image digitization technology and the development of milling devices have made it possible to optimize various processes in Dentistry. The use of intraoral scanning and the CAD-CAM system (CAD - Computer Aided Design; CAM - Computer Aided Manufacturing) has improved the performance of prosthetic rehabilitations, allowing the obtaining of high quality parts in a reduced time. The objective of this work is to report a case of rehabilitation of a lower central incisor using intraoral scanning, with an Omnicam scanner (Dentsply Sirona) and application of the CAD-CAM system.

The Applications of 3D-Printing Technology in Prosthodontics: A Review of the Current Literature.

Prosthodontics has become increasingly popular because of its cosmetic attractiveness. 3D printing has revolutionized prosthodontics, enabling the creation of high-quality dental prostheses. It creates detailed restorations, such as crowns, bridges, implant-supported frameworks, surgical templates, dentures, and orthodontic models. In addition, it saves production time but faces challenges such as elevated expenses and the requirement for innovative materials and technologies. This review gives insights into the uses of 3D printing in prosthodontics, presenting how it has significantly changed clinical practices. This article discusses different materials and techniques. Additionally, it showcases the capacity of 3D printing to improve prosthodontic practice and proposes prospects for future investigation.

Opinions of Dental Technologists in Nigeria on Quality of Work Authorization for Removable Dental Prosthesis.

BACKGROUND: When fabricating a removable dental prosthesis, clear and sufficient communication between the dentist and dental laboratory technologist is crucial to ensure a successful outcome. OBJECTIVES: To evaluate the quality of communication between dentists and dental laboratories via work authorizations for the fabrication of removable prosthesis across the six geographical zones in Nigeria. MATERIALS AND METHODS: A cross-sectional descriptive study was conducted among dental technologists in Nigeria. A 22- item, online survey questionnaire was sent to all the participants through their respective states and the National Dental Technologist Association across the six geographical zones in the country. Data obtained were analyzed. Association between variables was carried out using the Chi-square test. Binary logistic regression was used to predict group membership. RESULTS: A total of 62 dental technologists participated in this study; the highest percentage of respondents, 29.1% was from South West. Only 21% of the respondents reported that they received work authorizations with adequate information to complete a denture setup most time. Also, 16.1% of the technologists received casts with adequate rest seats and guide planes prepared on the abutment teeth. Eighteen respondents (29%) stated that the authorization card does not contain all the required information. Fabrication of more than 7cast RPDs could be used to predict dental technologists who hold a positive view on the provision of quality work authorization by dentists. (P≤0.05).

CONTEXTE: Lors de la fabrication d'une prothèse dentaire amovible, une communication claire et suffisante entre le dentiste et le technologue de laboratoire dentaire est cruciale pour garantir un résultat satisfaisant. OBJECTIFS: Évaluer la qualité de la communication entre les dentistes et les laboratoires dentaires par le biais d'autorisations de travail pour la fabrication de prothèses amovibles dans les six zones géographiques du Nigeria. MATÉRIEL ET MÉTHODES: Une étude descriptive transversale a été menée auprès des prothésistes dentaires au Nigeria. Un questionnaire d'enquête en ligne de 22 questions a été envoyé à tous les participants par l'intermédiaire de leurs États respectifs et de l'Association nationale des technologues dentaires dans les six zones géographiques du pays. Les données obtenues ont été analysées. L'association entre les variables a été réalisée à l'aide du test du chi carré. La régression logistique binaire a été utilisée pour prédire l'appartenance à un groupe. RÉSULTATS: Au total, 62 technologues dentaires ont participé à cette étude ; le pourcentage le plus élevé de répondants, soit 29,1 %, provenait du Sud-Ouest. Seulement 21% des répondants ont déclaré avoir reçu des autorisations de travail avec des informations adéquates pour réaliser un montage de prothèse dentaire la plupart du temps. De plus, 16,1 % des technologues ont reçu des moulages avec des sièges de repos et des plans de guidage adéquats préparés sur les dents piliers. Dix-huit répondants (29 %) ont déclaré que la carte d'autorisation ne contenait pas toutes les informations requises. La fabrication de plus de sept prothèses dentaires de recouvrement pourrait être utilisée pour prédire les technologues dentaires qui ont une opinion positive sur la fourniture d'une autorisation de travail de qualité par les dentistes. (P≤0.05). CONCLUSIONS: La qualité de l'autorisation de travail pour la fabrication de prothèses dentaires amovibles était moins qu'adéquate dans les six zones géographiques du Nigeria. Cela laisse généralement une grande partie de la prise de décision aux technologues de laboratoire dentaire. MOTS-CLÉS: Technologue dentaire, prothèse dentaire amovible, autorisation de travail.

Clinical performance of zirconia-based tooth-supported fixed dental prostheses: a systematic review and meta-analysis.

OBJECTIVES: This study aimed to investigate the clinical performance of zirconia-based fixed dental prostheses (FDPs) in comparison to metal-ceramic (MC) FDPs. METHODS: A comprehensive search on MEDLINE (PubMed), Web of Science (Core Collection), Scopus up to June 2024 was conducted. Studies that compared the success, survival and complication rates between zirconia based FDPs and MC FDPs were eligible for inclusion. RESULTS: Thirty-one articles were identified, of which 22 were included for systematic review and 7 RCTs were included for meta-analysis. 10, 9 and 3 studies were classified to mean follow-up ≤ 5 years, 5 years < mean Follow-up ≤ 10 years, mean Follow-up >10 years, respectively. In the pooled analysis, 180 bilaminar zirconia (ZC) FDPs and 206 MC FDPs were included. ZC FDPs were significantly associated with more failures (RR=3.64, p=0.009) and more Ceramic Chipping (RR=2.92, p<0.0001) when compared to MC FDPs. Higher risks of Framework Fracture (RR=4.57, p=0.18), Loss of Retention (RR=4.79, p=0.17), Secondary Caries (RR=1.25, p=0.68), Endodontic complications (RR=1.30, p=0.74) and Marginal Integrity (RR=1.07, p=0.88) were also found in ZC FDPs when compared to those of MC FDPs, but with no statistical difference. CONCLUSION: The current evidence continues to support the preference for traditional MC FDPs over ZC FDPs. Studies indicate that ZC FDPs have higher failure rates and more complications compared to MC FDPs, with ceramic chipping being a significant concern. There is lack of long term (>10 years follow-up) evidence of the clinical performance of ZC FDPs and monolithic zirconia FDPs. CLINICAL SIGNIFICANCE: The study suggests that despite the growing popularity of zirconia, evidence shows MC FDPs may still be considered preferable to ZC FDPs.

Survival Rate, Biomechanical Complications, and Patient Satisfaction of Implant-Supported FRC Full-Arch Prostheses: A Retrospective Study with Follow up of 5 Years.

Statement of the Problem: The satisfaction of patients with dentures on implants has different points of view that become fundamental aspects for the development of research on the quality of life of these patients, the eventual biomechanical complications to which these prostheses and implants can be subjected, and design considerations for cantilever extensions. Purpose: The objective of research was to assess the implants and prosthesis survival rates, biomechanical complications relative to the length of the distal extensions (cantilevers), and the satisfaction of the patients with a fixed implant-supported full-arch fiber-reinforced composites prosthesis. Materials and Method: A retrospective clinical and radiographic cohort study was developed. Clinical records of a selected cohort were analyzed according to inclusion and exclusion criteria. Data on a patient who underwent to fixed implant-supported full-arch fiber-reinforced composites prosthesis at least of five years of function were collected. Data analysis was performed using Kaplan-Meier curves and Fisher's Exact Test. P values less than 0.05 were considered statistically significant. Results: After insertion, 1 of 29 prostheses failed, the overall prosthetic survival rate observed at 5 years was 96.5%. Of the 120 implants placed in 28 patients, only 4 patients experienced loss of an implant during the 5 years of observation; the implant survival rate throughout the observation period was 86.2%. Distal extension seems to negatively affect the prognosis of implant-supported rehabilitation. Regarding the level of satisfaction of the patient with the prosthesis, none reported being uncomfortable or dissatisfied neither with their appearance nor with the taste of food throughout the studied period. Conclusion: No relevant associations were found between the variables involved. The study found the improvement in quality of life following the installation of fixed rehabilitation on the patients. Once the potential benefits of patients are obtained, controlled clinical trials are encouraged.

Artificial neural networks development in prosthodontics - a systematic mapping review.

OBJECTIVES: This study aimed to systematically categorize the available literature and offer a comprehensive overview of artificial neural network (ANN) prediction models in prosthodontics. Specifically, the present research introduces a systematic analysis of ANN aims, data, architectures, evaluation metrics, and limitations in prosthodontics. DATA: The review included articles published until June 2024. The search terms included "prosthodontics" (and related MeSH terms), "neural networks", and "deep learning". Out of 597 identified articles, 70 reports remained after deduplication and screening (2007-2024). Of these, 33% were from 2023. Implant prosthodontics was the focus in approximately 29% of reports, and non-implant prosthodontics in 71%. SOURCES: Data were collected through electronic searches of PubMed MedLine, PubMed Central, ScienceDirect, Web of Science, and IEEE Xplore databases, along with manual searches in specific journals. STUDY SELECTION: This study focused on English-language research articles and conference proceedings detailing the development and implementation of ANN prediction models specifically designed for prosthodontics. CONCLUSIONS: This study shows how ANN models are used in implant and non-implant prosthodontics, with various types of data, architectures, and metrics used for their development and evaluation. It also reveals limitations in ANN development, particularly in the data lifecycle. CLINICAL SIGNIFICANCE: This study equips practitioners with insights, guiding them in optimizing clinical protocols through ANN integration and facilitating informed decision-making on commercially available systems. Additionally, it supports regulatory efforts, smoothing the path for AI integration in dentistry. Moreover, it sets a trajectory for future exploration, identifying untapped tools and research avenues, fostering interdisciplinary collaborations, and driving innovation in the field.

Inflammatory and adhesion profile of gingival fibroblasts to lithium disilicate ceramic surfaces.

OBJECTIVES: Lithium disilicate (LS) ceramic emerges as a compelling option for customized implant abutments. However, ensuring its safety and reliability requires clarification on key aspects, notably its impact on inflammation and potential for cell adhesion. This study delves into these considerations, examining the influence of LS ceramic on cytokine release and the transcriptional profile of human gingival fibroblasts (hGFs) in direct contact with various LS surfaces. METHODS: hGFs were cultured on LS disks featuring three distinct surfaces (unpolished, polished, and polished glaze), while titanium disks served as reference material and cells cultured directly on plates as controls. The surface of the disks was analyzed using a scanning electron microscope. The cell metabolism was analyzed by MTT test, cytokine release by MAGPIX and the expression of genes related to cell adhesion was evaluated by qPCR. RESULTS: The disks exhibited similar topography with smooth surfaces, except for the unpolished LS disks, which had an irregular surface. Contact with LS surfaces did not substantially reduce cell metabolism. Moreover, it generally decreased cytokine release compared to controls, particularly pro-inflammatory mediators like IL-1ß, IL-6, and TNF-α. Significantly increased expression of genes related to cell adhesion to LS was observed, comparable to titanium, the gold standard material for implant abutments. SIGNIFICANCE: This study unveils that LS ceramic not only fails to trigger pro-inflammatory cytokine release, but also significantly enhances gene expression associated with cell adhesion. These mechanisms are closely linked to gene pathways such as PTK2, SRC, MAPK1, and transcription factors ELK-1 and MYC. In summary, the findings underscore LS ceramic's potential as a biocompatible material for implant abutments, shedding light on its favorable inflammatory response and enhanced cell adhesion properties.

Clinical outcome of monolithic zirconia on bonded or mechanically retained prefabricated titanium-base: A 4-year retrospective study.

OBJECTIVE: To assess the clinical performance of monolithic screw-retained implant-supported zirconia crowns (MSI) bonded or mechanically retained on prefabricated Ti-bases using a complete digital workflow. METHODS: A retrospective analysis was conducted on patients who underwent single dental implant procedures between January 2017 and May 2018. Inclusion criteria were: patients over 18 years of age; implants placed in posterior sites; MSI on prefabricated Ti-base realized by using a complete digital workflow; a minimum follow-up period of 2 years. Cemented crowns and fixed dental prosthesis were excluded. Mechanical complications included: fracture of Ti-base; loss of retention; loosening of Ti-base screws. Technical complications included: fracture and debonding of monolithic zirconia. Biological complication was set strictly at a probing pocket depth of 5 mm and bleeding on probing or pus secretion. RESULTS: A total of 144 dental implants placed in 127 patients were included, 73 with a fully tapered implant system (BLX) and 71 with a conical connection system (Nobel Parallel CC). Of the 73 BLX implants, 4 experienced loosening of the Ti-base screw, while 3 Nobel Parallel CC implants experienced the same problem. In addition, 4 fractures of the Ti-base and 6 fractures of the inner surface of the monolithic zirconia were observed in the Nobel Parallel CC implants. Cumulative survival was 100 % for bonded crowns and 85 % for mechanically retained crowns. Radiographic evaluation revealed a mean CBL of 0.12 mm for the BLX and 0.13 mm for the Nobel Parallel CC implants with no statistically significant differences between the Ti-base types. There was no evidence of bleeding on probing or pus secretion. All probing pocket depths were <3 mm. CONCLUSION: The use of a prefabricated Ti-base remains a clinically acceptable choice, however, MSIs bonded to prefabricated Ti-bases had fewer mechanical and technical complications than the MSI mechanically retained to a prefabricated Ti-base.

Effect of cleaning solution on surface properties of 3D-printed denture materials.

PURPOSE: To evaluate the effect of cleaning solutions on surface properties of 3D-printed resins. MATERIALS AND METHODS: Seven different resin materials for denture base and teeth were used in the form of 280 half-disks. Samples were randomly assigned to two cleaning groups (FD, FreshDent; PO, Polydent), with daily 2- or 3-min immersion followed by water storage, repeated for 30 days. Samples were then cleaned in an ultrasonic bath with water and analyzed for surface roughness (Keyence, VHX-7000N) and hardness (Shimadzu, HMV-2 series). The pH of cleaning solutions was analyzed over 5-min and the surface morphology of specimens was analyzed via scanning electron microscopy (SEM). Statistical analysis used two-way ANOVA (α = 0.05). RESULTS: Surface roughness of base materials was significantly affected (p < 0.001), whereas roughness of teeth materials was not. As for hardness, there was a significant interaction between materials and cleaning solution for both, base (p < 0.001) and teeth (p < 0.001). For teeth materials, PO significantly increased Denture's (Dentca) hardness and decreased that of Rodin's (Pac Dent), while PO significantly increased Rodin's Base (Pac Dent) hardness. The hardness of Flexcera Ultra (Envision Tec), Glidewell (Glidewell), Lucitone (Dentsply Sirona), and NextDent (NextDent) teeth and base materials were not affected by the cleaning solution. Overall, the pH of FD averaged 7.3 and PO averaged 6.6. All the SEM images indicated surface irregularities after immersion in either FD or PO. CONCLUSIONS: One-month of storage and cyclic cleaning of 3D- printed resins did not affect surface roughness but had a significant impact on hardness. The cleaning solutions' effect was not homogeneous among materials.

Comparison of Maintenance in Different Materials for Implant Dental Prostheses.

Context: In contemporary prosthodontics, implant-supported dental prostheses are frequently utilized to restore function and esthetics for individuals who are edentulous. The prosthetic material selection has a big impact on long-term performance and maintenance needs. Methods: A retrospective review of patient files from the dental implant clinic of a tertiary care facility was done. Included were patients who had dental prosthesis supported by implants between January 2018 and December 2022. Data were gathered and examined on the prosthesis material, follow-up visits, and maintenance interventions (adjustments, repairs, and replacements). Results: Materials for 50 prostheses made of porcelain, 45 prostheses made of acrylic, 35 prostheses made of metal, and 40 prostheses made of composite were assessed. When it came to modifications and repairs, porcelain prosthesis needed less work than acrylic prostheses. Composite prostheses required the least amount of maintenance overall, whereas metal prostheses indicated a considerable demand for maintenance. Conclusion: Superior durability is provided by porcelain, frequent repairs are needed for acrylic, structural strength is provided by metal, and composite material gives promising esthetics with low maintenance requirements. These results highlight how crucial it is to take material properties into account when choosing a prosthesis to maximize long-term results and patient happiness.

In Vitro Effect of Anodization of Titanium Abutments on Color Parameters and Color Difference of Lithium Disilicate All-Ceramic Crowns.

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.

Glass Ionomer Cement Induced Angioedema: Seldom Encounter in Prosthodontic Practice-A Case Report.

Contact allergies are frequently encountered in dental practice, and their underlying causes are not readily apparent. These allergies can arise from allergic or anaphylactic responses triggered by commonly utilised dental materials in routine dental procedures or potentially result from the use of specific medications. This case presents a unique scenario involving a patient who sought prosthetic crowns following maxillary anterior teeth endodontic treatment. During the cementation of the prosthesis with glass ionomer cement, the patient unexpectedly experienced an acute allergic reaction in her upper lip. The patient received reassurance and was prescribed a 3-day course of oral corticosteroids and antihistamines, resulting in symptom relief within 24 h. This paper seeks to raise awareness among clinicians about the potential for contact allergic reactions and aims to emphasise the presentation and management of the uncommon incidence of angioedema during prosthodontic procedures.

On the suitability of photocuring-assisted DIW for manufacturing complex prosthesis from commercial dental composites.

A 3-D printing method to produce dental prostheses of complex shapes from a commercial, photocurable resin-ceramic slurry is developed and optimized. The microstructure, mechanical properties and wear behavior of the resulting material are evaluated and compared with a conventional/control sample and other ceramic-polymer dental composites. Commercial resin-ceramic dental slurries can be successfully extruded and appropriately photocured in a low cost 3-D printing system to produce cost-efficient complex dental parts that could be used in indirect restorations. The printing process does not appreciably introduce defects in the material and the 3-D printed composites exhibit mechanical properties (hardness, elastic modulus) and wear resistance comparable to the control material and analogous, conventional dental composites. The main wear mechanisms under sliding contact against a hard antagonist are plastic deformation at the asperity level and ceramic particle pull-out due to filler/matrix interfacial weakness.

Effect of cut-out rescanning protocol on the accuracy of digital impressions in convergent implants positioned at varying depths: An in vitro study.

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

Assessment of oral hygiene and quality of life in rehabilitated patients with fixed parcial dentures.

OBJECTIVE: Analyze the influence of oral hygiene guidance for the maintenance of fixed partial dentures (FPD) and the influence of this treatment on the quality of life (QL) of rehabilitated patients. MATERIAL AND METHODS: The Simplified Oral Hygiene Index (OHI-S) and Bleeding on Probing Index (BOP) methods was employed to evaluate oral hygiene (OH), and the OHIP-14 questionnaire to assessment QL. The sample consisted of 33 patients (26 females and 7 males, mean age 51.53 years) in treatment with FPD. The OH and QL assessments were conducted in temporary FPD placing session and 30 days after definitive cementation. R e s u l t s: OHI-S and BOP showed increasing results (p <0.05) comparing initial and final assessments. There was a negative correlation between OHI-S and BOP, in both periods of analysis. The OHIP-14 showed a significant result according to the Likert scale scores, with an impact reduction from 9.33 to 0.57. CONCLUSIONS: It was concluded that FPD rehabilitations need of properly oral hygiene guidance, that could be influence on oral health status. In addition, the FPD rehabilitation improved the QL of the patients.

Comparison of Aesthetic, Mechanical Outcome, and Bone Loss in Angulated Screw Channels (ASCs) and Cement-Retained Implant-Supported Prosthesis: A Case-Control Study.

Angulated-screw channels (ASCs) allow the clinician to employ screw-retained restorations in almost all cases, as the access hole can be moved away from the vestibular portion of the crown, where it would jeopardize the final esthetic result. The objective of this study was to compare screw-retained restorations employing ASCs with restorations cemented on angled abutments. In this study, 30 subjects, equally divided into two groups: group 1 (cemented restorations on angulated abutments) and group 2 (screw-retained restorations adopting ASCs), were treated and retrospectively compared after 2 years using the pink esthetic score (PES) and the white esthetic score (WES). All restorations were in use at the last follow-up, with a survival rate of 100%. Three mechanical complications were observed (2 chippings and 1 crown came loose), with a success rate of 93% in group 1 and 87% in group 2 (p > 0.05). No statistically significant differences were reported regarding the esthetic outcome; the marginal bone loss (MBL) showed better results for the screw-retained restorations, both at the distal aspect (group 1 = 0.98 mm ± 0.16; group 2 = 0.45 mm ± 0.06; p = 0.006) and at the mesial aspect (group 1 = 1.04 ± 0.27; group 2 = 0.45 ± 0.005; p < 0.001). From an esthetical perspective, screw-retained restorations with ASCs and cemented restorations on angulated abutments are both effective means of restoring implants; both have excellent esthetic outcomes, but screw-retained restorations have reduced bone loss when compared to cemented ones but are more prone to mechanical complications. Still, our results must be cautiously observed given the reduced dimension of our sample. Larger studies are needed to confirm our findings.

The mechanical complications and behavior of angulated dental implant abutment systems versus conventional abutments, a narrative review.

Background: Angulated screw channel (ASC) abutment allows off-axis dental implants to be used in dental restorations without the need for cementation. As this is a relatively new system, research on its clinical performance is limited. Objectives: To summarize the available in-vitro and in-vivo studies on the mechanical and technical issues associated with the ASC system and compare its clinical performance with that of conventional implant-supported abutments. Methods: A comprehensive literature search in PubMed, Web of Science, and ScienceDirect databases was performed, focusing on articles about angulated (angled) screw channel (ASC) systems published in English between January 2015 and November 2023. Only in-vitro and in-vivo studies were included. Results: After analyzing the recorded articles, 26 studies (11 in vivo and 15 in vitro) were included in the final discussion and review. Conclusion: Although the ASC system is still relatively new, and is presently outperformed by conventional abutment systems in terms of technical and mechanical properties, in short- and medium-term in-vivo studies, it was shown reliable for retaining single or multiple-unit implant restorations in both posterior and anterior zones. Still, further long-term clinical research is needed to fully elucidate the risk factors associated with ASC failures.

A survey for the use of torque-limiting devices among dental clinicians in Europe.

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.

Clinical and radiographic evaluation of implant-supported single-unit crowns with cantilever extensions: A systematic review and meta-analysis.

PURPOSE: The purpose of this systematic review and meta-analysis was to analyze the clinical and radiographic outcomes of patients rehabilitated using a single implant supporting a crown with a cantilever extension or two implants supporting two single crowns. METHODS: Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) 2020 guidelines, a systematic review of relevant literature published from 2000 was conducted in the Cochrane Library, Scopus, and MEDLINE databases. Moreover, a manual search was performed. A meta-analysis of the resulting data was carried out. Peri-implant marginal bone level, probing pocket depth, prevalence of technical and mechanical complications, implant survival rate, and prosthesis survival rate were assessed. RESULTS: The meta-analysis showed a non-statistically significant change in the peri-implant marginal bone level and probing pocket depth in the cantilever group and revealed a non-significant prevalence of technical complications, showing a 27% rate in the cantilever group. The analysis of the prosthesis survival rate in the cantilever group showed a mean survival rate of 99% while the comparison of the implant survival between the two groups revealed an odds ratio of 0.50. CONCLUSIONS: The use of a single implant supporting a crown with a cantilever extension does not result in lower implant survival rate if compared with two implants supporting two single crowns. Moreover, a high prosthesis survival rate was observed in the cantilever group even if the high prevalence of complications should be carefully considered by the clinician.

Application of artificial intelligence in dental crown prosthesis: a scoping review.

BACKGROUND: In recent years, artificial intelligence (AI) has made remarkable advancements and achieved significant accomplishments across the entire field of dentistry. Notably, efforts to apply AI in prosthodontics are continually progressing. This scoping review aims to present the applications and performance of AI in dental crown prostheses and related topics. METHODS: We conducted a literature search of PubMed, Scopus, Web of Science, Google Scholar, and IEEE Xplore databases from January 2010 to January 2024. The included articles addressed the application of AI in various aspects of dental crown treatment, including fabrication, assessment, and prognosis. RESULTS: The initial electronic literature search yielded 393 records, which were reduced to 315 after eliminating duplicate references. The application of inclusion criteria led to analysis of 12 eligible publications in the qualitative review. The AI-based applications included in this review were related to detection of dental crown finish line, evaluation of AI-based color matching, evaluation of crown preparation, evaluation of dental crown designed by AI, identification of a dental crown in an intraoral photo, and prediction of debonding probability. CONCLUSIONS: AI has the potential to increase efficiency in processes such as fabricating and evaluating dental crowns, with a high level of accuracy reported in most of the analyzed studies. However, a significant number of studies focused on designing crowns using AI-based software, and these studies had a small number of patients and did not always present their algorithms. Standardized protocols for reporting and evaluating AI studies are needed to increase the evidence and effectiveness.