Search

Objective To assess whether digital workflow gives better results than the conventional one in the single implant crowns, when analyzing the impression time, patient preference, time efficiency, and adjustment time. Material and methods MEDLINE, Embase, and Cochrane were searched and supplemented via hand search up to June 19, 2019. Only clinical trials assessing conventional versus digital workflows for single implant crowns were included. Impression time was evaluated using random effects meta-analysis, while patient preference, adjustment time, and time efficiency were reported descriptively. Results Among 1,334 publications identified, ten studies were included. The random effects models revealed statistically significant reduction in time in the digital impression group when compared to the conventional group by the mean meta-analysis (MD: 8.22 [95% CI: 5.48, 10.96]). Analysis from immediate digital impression versus conventional (MD: 3.84 [95% CI: 3.30, 4.39]) and regular digital impression versus conventional (MD:10.67 [95% CI: 5.70, 15.65]) showed statistically significant reduction in time on using the digital impression. Impression time in the digital process ranged between 6 min 39 s and 20 min, whereas for conventional, it was between 11.7 and 28.47 min. Patients showed greater preference for digital impression. Adjustment time in the digital process ranged between 1.96 and 14 min, whereas for conventional, it was between 3.02 and 12 min. Time efficiency in the digital process ranged between 36.8 and 185.4 min, whereas for conventional, it was between 55.6 and 332 min. Conclusion The digital workflow has demonstrated better clinical efficiency considering impression time, patient preference, and time efficiency. According to the adjustment time, different results were presented.

Objectives The aim of this research was to develop a sensor of approximation by reflectance for guided surgery with dental implants without flap detachment, and verify the effectiveness of this system. Materials and Methods Ten models of total edentulous arches were divided into two groups. Two implants of 3.5 × 11.5 mm (NeoDent) were inserted in each model; in Group 1 (G1), a stereolithographic guide NeoGuide system was used. In Group 2 (G2), the experimental approximation sensor was used for the insertion of the implants. The evaluation of the results was performed by overlapping the virtual planning images with the tomographies of the models of the implants inserted. Results There were no statistically significant differences between the guide and the sensor groups. The averages and standard deviations observed at the angulation of the guide was 4.15 (2.65 degrees) and 5.48 (2.85 degrees) at the sensor. The linear deviations at the cervical level were 0.002 (1.37) and 0.11 (1.47) mm and at the apical level 0.19 (1.28) and 0.21 (1.42) mm, respectively. Conclusions The use of a guide is important for the stabilization of the drills; the greatest challenge is to control the apical position of the implants, especially in highly reabsorbed edges. The experimental sensor can become an auxiliary tool to the stereolithographic guides; however, several difficulties must still be overcome to recommend the use of a sensor.

To evaluate the effect of blasting and bonding on abutment surface to prevent screw loosening in Morse taper connections.Twenty-eight Morse taper connection implants were divided into 4 groups: no treatment (G1), blasting (G2), bonding (G3), and blasting + bonding (G4). In groups G2 and G4, the abutments were blasted with aluminum oxide granules; in groups G3 and G4, the conical abutment region was covered with a thin layer of bond thread lock agent. In all implants, the abutment-implant joint was tightened at a torque of 35 Ncm. The specimens were submitted to the mechanical cycling, under an oblique load for 1.0 × 10 cycles. The torque was measured with a digital torque meter. Data were analyzed by the t test, one-way analysis of variance, and Tukey tests (95%).The loosening strength was significantly higher in group G4 (35.83 ± 3.02 Ncm). There was no significant difference among groups G1 (25.86 ± 1.96 Ncm), G2 (25.86 ± 3.29 Ncm), and G3 (26.14 ± 2.12 Ncm).The association of blasting and bonding on abutment surface can be used to prevent screw loosening in Morse taper implants.

Objectives: The aim of this study is to compare the mechanical characteristics of resins for 3D printers with the acrylic resins that have been used in Dentistry, according to the post-processing method. Materials and Methods: Using an SLA 3D printer (Form 2 – Formlabs, Massachusetts, USA), samples (discs) were produced with the printer’s resins, Dental SG®, Dental LT®, Clear®, and Grey®. Samples made of thermopolimerized and auto polymerized acrylic resins were produced as well (Gold Standart parameters). The Knoop Hardness (KH) tests were performed using microdurometer HMV-2 (Shimadzu, Kyoto, Japan). Results: The results showed the Dental SG resin presented the highest KH, compared with thermopolimerized acrylic resin, the Clear and Dental LT resins KH were compared with auto polymerized acrylic resin, and the non-post cured Grey resin (not for intraoral use), as well as the Dental LT resin, showed the lowest KH. Conclusions: Considering the hardness, the printer’s resins are comparable with the acrylic resins established, when the post-processing method is thoroughly followed. The absence of material’s post-processing reduce significantly the material’s hardness. Clinical relevance: Regarding the use of 3D printing in Dentistry, the development of materials adequate for the equipment, biocompatible for intraoral uses, and compatible mechanical proprieties are essential. Objetivos: O objetivo deste estudo é comparar as características mecânicas das resinas para impressoras 3D com as resinas acrílicas utilizadas em Odontologia, de acordo com o método de pós-processamento. Materiais e Métodos: Utilizando uma impressora SLA 3D (Form2 – Formlabs, Massachusetts, EUA), amostras (discos) foram produzidas com as resinas da impressora, Dental SG®, Dental LT®, Clear® e Grey®. Também foram produzidas amostras feitas de resinas acrílicas termopolimerizadas e autopolimerizadas (parâmetros Gold Standart). Os testes de dureza Knoop (KH) foram realizados usando o microdurômetro HMV-2 (Shimadzu, Kyoto, Japão). Resultados: Os resultados mostraram que a resina Dental SG apresentou o KH mais alto, em comparação com a resina acrílica termopolimerizada, as resinas Clear e Dental LT KH foram comparadas com a resina acrílica autopolimerizada e a resina Grey sem pós-cura (não para uso intraoral), assim como a resina Dental LT, apresentou o menor KH. Conclusões: Considerando a dureza, as resinas da impressora são comparáveis às resinas acrílicas, quando o método de pós-processamento é completamente seguido. A ausência do pós-processamento do material reduz significativamente a dureza do material. Relevância clínica: No que diz respeito ao uso da impressão 3D em Odontologia, o desenvolvimento de materiais adequados ao equipamento, biocompatíveis para usos intraorais e propriedades mecânicas compatíveis é essencial.

Objective The aim of this review was to update the literature with regard to the digital methods available by CEREC Chairside system to register and design the occlusion, to report their efficacy and technical innovations in the field of Restorative Dentistry. A search strategy was performed using the key-words: “virtual articulator,” or “CAD-CAM and occlusal recording,” or “CAD-CAM and occlusion register,” or “CAD-CAM and occlusal contacts,” or “CAD-CAM and prosthesis.” Material and Methods Inclusion criteria comprised studies evaluating the use of digital methods available by CEREC System for occlusal registration and design during prosthodontics treatment. PubMed and Cochrane library and reference lists were searched up to January 2016. Results The search resulted in 280 articles after removing duplicates. Subsequently, 233 records were excluded and 49 studies were selected for reading in full. Eleven articles were considered eligible for the systematic review (4 in vitro and 7 clinical studies). Conclusion Scientific evidence suggests that digital methods were accurate to register and design the occlusion of dental prostheses. Nevertheless, further clinical studies are required to establish a conclusion with regard to its accuracy in prosthodontics treatment. Clinical Significance Digital technologies allow the design of occlusal surfaces of CAD-CAM fabricated prostheses using innovative approaches. This systematic review aimed to update the literature to help dentists determine the most appropriate digital method to register and design the occlusal surface of CAD-CAM crowns. (J Esthet Restor Dent 28:208–220, 2016)

Compreender a importância de estrategias de impressao 3D e uma chave para obter aparelhos dentarios estaveis, aperfeicoados e consistentes utilizando tecnologias digitais. Este estudo tem como objetivo apresentar a influencia da inclinacao da impressao sobre a precisao do ajuste intraoral de placas de arco de cobertura total. As placas foram projetadas para dois pacientes com uso do software CAD e de uma impressora 3D SLA com diferentes inclinacoes (0, 30 e 90 graus), e o ajuste interno foi verificado na boca dos pacientes. Foi possivel verificar diferencas entre o ajuste interno das placas, com os piores resultados para placas com inclinacao de 90 graus, em­bora estudos mais detalhados sejam recomendados. DESCRITORES | Impressao tridimensional; Precisao; Medicao das dimensoes; Placa oclusal; Inclinacao da Impressao.

Digital workflow is an important tool in the development of intraoral appliances by additive manufacturing. The purpose of this article is to present a completely digital workflow that uses a free software program and a low-cost 3D printer to fabricate occlusal devices for managing temporomandibular dysfunction. Three-dimensional images were acquired of an open maxillomandibular relationship record by using a scanner. A free software program was used to design the devices, and a 3D printer was used to produce the appliances by using a biocompatible resin. An evaluation of the technique on 5 patients showed good internal fit of the 3D-printed device with a similar need for occlusal adjustment as conventionally fabricated occlusal devices.

Statement of problem Analysis of the wear coefficient (k) of the superficial and deep layers of acrylic resin teeth can help predict denture durability, but little has been published on the wear coefficient of denture teeth. Purpose The purpose of this in vitro study was to determine the k value for the superficial and deep layers of the acrylic resin teeth of 6 different brands by using the fixed-ball microabrasive wear method. Material and methods Six artificial tooth specimens of 4 commercial brands were tested: Artiplus IPN (Ar), Biotone IPN (Bi), Magister (Ma), Premium (Pr), Trilux (Tr), and SR Vivodent (Vi). Two specimens from each brand were created, one for the superficial layer and the other for the deep layer. The test was performed on fixed-ball microabrasive wear equipment set to operate at a constant normal force of 0.5 N and a rotation speed of 100 rpm. The test time periods were 5.00, 8.33, and 11.66 minutes. The characteristics of the wear craters were measured by using an optical microscope at a magnification of ×50 and Leica Microsystems software. Wear coefficient (k) values were deduced by using the Archard equation for abrasive wear, Q=k·N, and were analyzed by using 1-way analysis of variance, complemented by the Tukey HSD test (α=.05). A different analysis was used for each layer. Results The analysis of variance of the wear coefficient revealed significant differences among the groups regarding the superficial layers (P=.009). The Tukey HSD test showed that the k values for the superficial layers of Artiplus specimens were significantly lower than those of the Vivodent and Magister specimens. Conclusions One brand (Ar) presented significantly lower wear coefficient value for the surface layer. No difference in wear coefficient values was found among the tooth brands for the deep layer.

The process of tooth loss throughout life associated with severe occlusal wear may pose a challenge in the rehabilitation of partially edentulous arches. In these cases, many therapeutic procedures are necessary because each tooth must be restored to obtain the correct anatomical contour and recover the occlusal vertical dimension (OVD). A removable partial denture (RPD) with occlusal/incisal coverage, also known as an overlay RPD, is an alternative treatment option with fewer interventions, and, consequently, lower cost. This clinical report reviews the principles involved in the clinical indication for an overlay RPD, as well as the necessary planning and execution, to discuss the feasibility and clinical effectiveness of this treatment, identifying the indications, advantages, and disadvantages of this procedure through the presentation of a clinical case. The overlay RPD can be an alternative treatment for special situations involving partially edentulous arches in patients who need reestablishment of the OVD and/or realignment of the occlusal plane, and it can be used as a temporary or definitive treatment. The main advantages of this type of treatment are its simplicity, reversibility, and relatively low cost; however, further studies are needed to ensure the efficacy of this treatment option.

Statement of problem The accuracy of the virtual images used in digital dentistry is essential to the success of oral rehabilitation. Purpose The purpose of this systematic review was to estimate the mean accuracy of digital technologies used to scan facial, skeletal, and intraoral tissues. Material and methods A search strategy was applied in 4 databases and in the non–peer-reviewed literature from April through June 2017 and was updated in July 2017. Studies evaluating the dimensional accuracy of 3-dimensional images acquired by the scanning of hard and soft tissues were included. Results A total of 2093 studies were identified by the search strategy, of which 183 were initially screened for full-text reading and 34 were considered eligible for this review. The scanning of facial tissues showed deviation values ranging between 140 and 1330 μm, whereas the 3D reconstruction of the jaw bone ranged between 106 and 760 μm. The scanning of a dentate arch by intraoral and laboratorial scanners varied from 17 μm to 378 μm. For edentulous arches, the scanners showed a trueness ranging between 44.1 and 591 μm and between 19.32 and 112 μm for dental implant digital scanning. Conclusions The current digital technologies are reported to be accurate for specific applications. However, the scanning of edentulous arches still represents a challenge.

Introduction Mandibular molar uprighting is indicated when mesial inclination of the second molars occurs because of missing first molars. There are many methodologies to perform such movement. In this study, we aimed to analyze and compare the stress distributions in different molar uprighting techniques. Methods Four photoelastic models were designed to evaluate different mandibular second molar uprighting techniques: a miniscrew positioned in the retromolar region, a beta-titanium alloy cantilever spring, a beta-titanium alloy wire with a T-loop spring, and an 0.018-in stainless steel archwire with an open-coil spring between the second premolar and the second molar. Results On the miniscrew test specimen, the greatest concentration of strains was observed in the cervical zone of the distal root. The cantilever spring had many strains in the cervical zone of the mesial root. On the T-loop spring test specimen, mainly the observed strains were in the apical zone of the mesial root. The open-coil spring specimen showed fringes in the cervical zone and the apical zone of the mesial root without formation of large sequences of strains. Conclusions The miniscrew mechanical action had the least and the cantilever spring mechanical action had the greatest strain means on the roots of mandibular second molars.

The internal and marginal adaptation of a computer-aided design and computer-aided manufacturing (CAD-CAM) prosthesis relies on the quality of the 3-dimensional image. The quality of imaging systems requires evaluation.The purpose of this in vitro study was to evaluate and compare the trueness of intraoral and extraoral scanners in scanning prepared teeth.Ten acrylic resin teeth to be used as a reference dataset were prepared according to standard guidelines and scanned with an industrial computed tomography system. Data were acquired with 4 scanner devices (n=10): the Trios intraoral scanner (TIS), the D250 extraoral scanner (DES), the Cerec Bluecam intraoral scanner (CBIS), and the Cerec InEosX5 extraoral scanner (CIES). For intraoral scanners, each tooth was digitized individually. Extraoral scanning was obtained from dental casts of each prepared tooth. The discrepancy between each scan and its respective reference model was obtained by deviation analysis (μm) and volume/area difference (μm). Statistical analysis was performed using linear models for repeated measurement factors test and 1-way ANOVA (α=.05).No significant differences in deviation values were found among scanners. For CBIS and CIES, the deviation was significantly higher (P.05) for occlusal and cervical surfaces. With regard to volume differences, no statistically significant differences were found (TIS=340 ±230 μm; DES=380 ±360 μm; CBIS=780 ±770 μm; CIES=340 ±300 μm).Intraoral and extraoral scanners showed similar trueness in scanning prepared teeth. Higher discrepancies are expected to occur in the cervical region and on the occlusal surface.

Statement of problem Limited evidence is available comparing digital versus conventional impressions from the point of view of patient preference. Purpose The purpose of this systematic review was to identify and summarize the available literature related to patient-centered outcomes for digital versus conventional impression techniques. Material and methods The databases Medline, Cochrane, Science Direct, Scopus, and Embase were electronically searched and complemented by hand searches. All published papers available on the databases from 1955 to July 2016 were considered for title and abstract analysis. Results A total of 2943 articles were initially identified through database searches, of which only 5 met the inclusion criteria for qualitative analysis. Four studies comparing patient-reported outcome measures (PROMs) between conventional and digital impressions revealed that the digital technique was more comfortable and caused less anxiety and sensation of nausea. Only 1 study reported no difference between the techniques regardless of patient comfort. Two studies reported a shorter procedure for the conventional technique, whereas 3 studies reported a shorter procedure for the digital technique. Conclusions A lack of clinical studies addressing patient outcomes regarding digital prosthodontic treatments was observed among the included articles. However, current evidence suggests that patients are more likely to prefer the digital workflow than the conventional techniques.

Background Chemical modifications of the dental implant surface that improve the wettability result in a faster and better osseointegration. Purpose The aim of this randomized clinical trial was to evaluate the implant stability quotient (ISQ) of implants with similar designs, treated with 2 surfaces, sandblasted acid-etched (SAE) and hydrophilic SAE, within the initial 16 weeks of healing. Material and methods A total of 64 implants (32 SAE—control group and 32 modified SAE—test group) with the same design, length, and diameter (conical and compressive, 4.3 × 10 mm) were inserted into the posterior maxillae of 21 patients partially edentulous. The ISQ values were collected at post-surgery (T0), 1 week (T1), 2 weeks (T2), 3 weeks (T3), 5 weeks (T4), 8 weeks (T5), 12 weeks (T6), and 16 weeks (T7). Results None of the implants failed. Test group presented ISQ values higher than the control group (ANOVA—P

The aim of the present study was to perform a software-assisted radiographic assessment of the effect of platform-switching on marginal bone loss (MBL) around dental implants. Forty patients requiring a dental implant in non-grafted partially edentulous mandibles were enrolled and categorized into implants receiving a platform-matched abutment (control group) or implants with a platform-switched abutment (test group). Standardized digital periapical radiographs were taken at the time of implant placement (T0), at implant loading (T1) and 1-year after functional loading (T2). Software-assisted radiographic assessment of the MBL horizontal, vertical and area changes was performed and compared between time intervals (T1-T0, T2-T1 and T2-T0). Mean radiographic horizontal MBL (hMBL) and vertical MBL (vMBL) from implant placement to 1-year after implant loading (T2-T0) were significantly increased around platform-matched when compared to platform-switched abutments (1.04 mm vs 0.84 mm, p

Background There is no consensus on whether incisal coverage is a risk or a protective factor in preparations for ceramic veneers. Objective The aim of this systematic review and meta-analysis was to evaluate the survival rates of preparation designs for ceramic veneers with and without incisal coverage. Methods Primary clinical studies with the following characteristics were included: 1) studies related to ceramic laminate veneers and 2) prospective or retrospective studies conducted in humans. From the selected studies, the survival rates and failures rates for ceramic veneers were extracted according to preparation design, with or without incisal coverage. The Cochran Q test and the I 2 statistic were used to evaluate heterogeneity. Metaregression, meta-analysis were performed. Two reviewers searched in the MEDLINE (Pubmed) and Cochrane Central Register of Controlled Trials (Central) electronic databases, from 1977 to June 5, 2016, without language restrictions. Results Eight studies out of 1145 articles initially identified were included for risk of bias and systematic assessment. No study was identified for crystalline ceramic veneers. The estimated survival rate for laminate veneers with incisal coverage was 88% and 91% for those without incisal coverage. Incisal coverage presented an OR of 1.25. Conclusions Irrespective of the preparation designs, with or without incisal coverage, ceramic veneers showed high survival rates. As regard implications for future clinical research studies, randomized clinical studies are necessary to compare preparation designs with and without incisal coverage, and to provide clear descriptions of these preparation designs.

The digital smile design is a practical diagnosis method that can assist the clinician to visualize and measure dentogingival discrepancies. This clinical report aims to present the associated steps, from the diagnosis of the alterations diagnosis through to the final aesthetic result. A 37-years-old female patient presented as her main complaint the tooth form and colour discrepancies. Applying the digital smile design principle, the necessary measures for a harmonic smile correction could be accurately determined. The initial diagnosis led to a wax up of the master cast that was duplicated in acrylic resin directly in the mouth. This temporary restoration guided the periodontal surgery and the final pressed ceramic crown restoration. We conclude that the digital smile design concept seems to be a useful tool to achieve a satisfactory aesthetic result.