A facially driven complete-mouth rehabilitation with ultrathin CAD-CAM composite resin veneers for a patient with severe tooth wear: A minimally invasive approach.

The development of technologies that include face scanning and dental software has improved workflows in dentistry. Digital files make it possible to create a 3-dimensional virtual image of the patient that helps the clinician plan treatment and make decisions, reducing uncertainty and improving communication. This report describes the complete-mouth rehabilitation of a patient with severe tooth wear. The treatment adopted a minimal intervention approach, applying adhesive veneers in areas where the tooth structure was affected and used a computer-aided design and computer-aided manufacturing (CAD-CAM) workflow to prepare nanoceramic composite resin materials with a high filler loading.

Effect of 2% Chlorhexidine Following Acid Etching on Microtensile Bond Strength of Resin Restorations: A Meta-Analysis.

Background and Objectives: The aim of this systematic review was to examine the effect of 2% chlorhexidine following acid etching on the microtensile bond strength of resin restorations for different follow-up times. Materials and Methods: A thorough search of PubMed, Scopus, and Embase databases were conducted. In vitro experimental studies or in vivo studies published up to December 2018 with an experimental group treated with a 2% chlorhexidine solution following acid etching and a control group were included, wherein the final restoration used a resin composite in both the groups. Results: Twenty-one articles were identified for qualitative analysis and 18 for meta-analysis. The difference in the means of microtensile bond strength between the two groups was calculated for the different follow-up times. The differences were significant for 6 months (4.30 MPa; 95% CI 2.72-5.89), 12 months (8.41 MPa; 95% CI 4.93-11.88), and 2-5 years including aged and thermocycling samples (9.08 MPa; 95% CI 5.36-12.81). There were no significant differences for the type of adhesive used. A meta-regression model showed a significant effect of time on the microtensile bond strength. Conclusions: The application of a 2% chlorhexidine solution after acid etching increased the microtensile bond strength significantly for follow-up times of 6 months or more. The adhesive type had no influence.

Volumetric variation of peri-implant soft tissues in convergent collar implants and crowns using the biologically oriented preparation technique (BOPT)

Background: To evaluate the changes in the peri-implant soft tissues of convergent collar implants with biologically oriented preparation technique (BOPT) crowns, 10 months after loading. Material and Methods: A pilot study was carried out from January 2016 to October 2017 involving 14 patients with one or two implants in the posterior mandibular sector. A total of 32 convergent collar implants were placed using a non-submerged protocol. Three months later the provisional cemented crowns were fitted using the BOPT approach with the finish line 1-1.5 mm below the gingival margin, simulating coronal emergence of a natural tooth. The soft tissue changes were measured with an intraoral scanner at two different time points: a) on the day of provisionalization, before prosthetic loading; and b) 10 months later without the provisional prosthesis. The STL files were superimposed and the soft tissue changes were recorded using a color scale with measurement of the volumetric changes in mm3 Results: A mean increase in peri-implant mucosal volume of 64.7 mm3 was observed in 29 implants. The zones with the greatest increase in soft tissue volume were the papillae of implants with adjacent teeth and the peri-implant buccal margin. Three implants showed a mean decrease in soft tissue volume of -25.1 mm3. Conclusions: The fitting and design of crowns using the biologically oriented preparation technique (BOPT) over convergent collar implants affords a significant increase in peri-implant soft tissue volume both at the level of the papillae and in the buccal margin

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Remineralization effects of conventional and experimental ion-releasing materials in chemically or bacterially-induced dentin caries lesions.

OBJECTIVES: The aim of this study was to evaluate the remineralization effects of conventional and experimental ion-releasing materials on different artificial dentin carious lesions. METHODS: Forty human dentin discs were submitted to different demineralization protocols for simulated caries lesion: (D1) Shallow chemically-induced caries, (D2) deep chemically-induced caries, (D3) deep bacterially-induced caries. Each disc was divided in five parts; one of those served as baseline control. The remaining parts of each disc (n=12-16/group) were treated using the following materials: EXP, an experimental resin-based bioactive material consisting of a self-etch primer and an adhesive containing a fluoride-doped bioglass; GIC, a glass ionomer cement (Riva LC); MTA, Mineral Trioxide Aggregate (ProRoot MTA); BIO, a calcium silicate cement (Biodentine). Specimens were mounted in a dual-chamber device to simulate the exposure to pulpal pressure and oral fluids. After 3 months, mineral and mechanical gains were assessed using transverse microradiography (vol% × µm) and microhardness measurements (VHN). Characterization using confocal microscopy and transmission electron microscopy (TEM) was also performed. RESULTS: All four restorative materials induced mineral gains regardless of the protocol for caries lesion, without significant differences between materials. Microhardness significantly increased in the groups BIO and MTA, but not GIC; EXP only provided hardness gains in D3-lesions. Fluorescence and confocal microscopy confirmed these results. There was a clear "top-down" remineralization in the groups BIO and MTA, and "bottom-up" intrafibrillar collagen remineralization in EXP. SIGNIFICANCE: Mineral gains did not always translate into hardness gains. Biodentine and MTA induced evident mineral precipitation, but intra/inter-fibrillar collagen mineral infiltration was only provided by biomimetic remineralisation via the use of the experimental adhesive. Complete remineralization of caries lesions remains a challenge.

Accuracy of 4 digital scanning systems on prepared teeth digitally isolated from a complete dental arch.

STATEMENT OF PROBLEM: The accuracy of digital scanners is acceptable for scanning a complete dental arch. However, whether that accuracy is sufficient for only 1 tooth within the dental scan of a complete dental arch is unclear. PURPOSE: The purpose of this in vitro study was to evaluate and compare the accuracy of 4 intraoral scanners on a complete dental arch and on prepared teeth digitally isolated from the digital scan in terms of trueness and precision. MATERIAL AND METHODS: A model of a complete dental arch with tooth preparations was scanned 40 times with each of the 4 digital scanners. Their accuracy was evaluated by using 3-dimensional (3D) software to compare the test models with a highly accurate reference model. The data were digitally processed to isolate the prepared teeth and evaluate them in the same way. The data were statistically analyzed using the Levene test and the Tamhane's T2 test (α=.05). RESULTS: In scans of a complete dental arch, the True Definition scanner had the best accuracy values, followed by TRIOS, iTero, and Omnicam. For prepared teeth isolated from the dental arch, both True Definition and TRIOS had the best values, followed by iTero and Omnicam. CONCLUSIONS: In both long-span scans of the complete dental arch and isolated prepared teeth, the True Definition scanner had the greatest accuracy, closely followed by TRIOS.

Correction: Accuracy of four digital scanners according to scanning strategy in complete-arch impressions.

[This corrects the article DOI: 10.1371/journal.pone.0202916.].

Accuracy of four digital scanners according to scanning strategy in complete-arch impressions.

STATEMENT OF PROBLEM: Although there are specific and general digital scanning guidelines depending on the system used, it is important to have the necessary flexibility in the acquisition of three-dimensional (3D) images to adapt to any clinical situation without affecting accuracy. PURPOSE: The purpose of this in vitro study was to identify and compare the scanning strategy with the greatest accuracy, in terms of trueness and precision, of four intraoral scanners in the impression of a complete dental arch. MATERIAL AND METHODS: Four digital scanners were evaluated with a 3D measuring software, using a highly accurate reference model obtained from an industrial scanner as a comparator. Four scanning strategies were applied 10 times on a complete maxillary arch cast inside a black methacrylate box. The data were statistically analyzed using one-way analysis of variance (ANOVA) and post hoc comparisons with Tamhane T2 test. RESULTS: The trueness of the Trios and iTero system showed better results with strategy "D," Omnicam with strategy "B," and True Definition with strategy "C". In terms of precision, both iTero and True Definition showed better results with strategy "D", while Trios showed best results with strategy "A" and Omnicam with strategy "B". There were significant differences between the scanning strategies (p<0.05) with the iTero scanner, but not with the other scanners (p>0.05). CONCLUSIONS: The digital impression systems used in the experiment provided sufficient flexibility for the acquisition of 3D images without this affecting the accuracy of the scanner.

Relationship between resolution and accuracy of four intraoral scanners in complete-arch impressions.

BACKGROUND: The scanner does not measure the dental surface continually. Instead, it generates a point cloud, and these points are then joined to form the scanned object. This approximation will depend on the number of points generated (resolution), which can lead to low accuracy (trueness and precision) when fewer points are obtained. The purpose of this study is to determine the resolution of four intraoral digital imaging systems and to demonstrate the relationship between accuracy and resolution of the intraoral scanner in impressions of a complete dental arch. MATERIAL AND METHODS: A master cast of the complete maxillary arch was prepared with different dental preparations. Using four digital impression systems, the cast was scanned inside of a black methacrylate box, obtaining a total of 40 digital impressions from each scanner. The resolution was obtained by dividing the number of points of each digital impression by the total surface area of the cast. Accuracy was evaluated using a three-dimensional measurement software, using the "best alignment" method of the casts with a highly faithful reference model obtained from an industrial scanner. Pearson correlation was used for statistical analysis of the data. RESULTS: Of the intraoral scanners, Omnicam is the system with the best resolution, with 79.82 points per mm2, followed by True Definition with 54.68 points per mm2, Trios with 41.21 points per mm2, and iTero with 34.20 points per mm2. However, the study found no relationship between resolution and accuracy of the study digital impression systems (P >0.05), except for Omnicam and its precision. CONCLUSIONS: The resolution of the digital impression systems has no relationship with the accuracy they achieve in the impression of a complete dental arch. The study found that the Omnicam scanner is the system that obtains the best resolution, and that as the resolution increases, its precision increases. Key words:Trueness, precision, accuracy, resolution, intraoral scanner, digital impression.

Correction: Mechanical properties of provisional dental materials: A systematic review and meta-analysis.

[This corrects the article DOI: 10.1371/journal.pone.0193162.].

Mechanical properties of provisional dental materials: A systematic review and meta-analysis.

Provisional restorations represent an important phase during the rehabilitation process, knowledge of the mechanical properties of the available materials allows us to predict their clinical performance. At present, there is no systematic review, which supports the clinicians' criteria, in the selection of a specific material over another for a particular clinical situation. The purpose of this systematic review and meta-analysis was to assess and compare the mechanical properties of dimethacrylates and monomethacrylates used in fabricating direct provisional restorations, in terms of flexural strength, fracture toughness and hardness. This review followed the PRISMA guidelines. The searches were conducted in PubMed, Embase, Web of Science, Scopus, the New York Academy of Medicine Grey Literature Report and were complemented by hand-searching, with no limitation of time or language up to January 10, 2017. Studies that assess and compare the mechanical properties of dimethacrylate- and monomethacrylate-based provisional restoration materials were selected. A quality assessment of full-text articles were performed according to modified ARRIVE and CONSORT criteria and modified Cochrane Collaboration's tool for in vitro studies. Initially, 256 articles were identified. After removing the duplicates and applying the selection criteria, 24 articles were included in the qualitative synthesis and 7 were included in the quantitative synthesis (meta-analysis). It may be concluded that dimethacrylate-based provisional restorations presented better mechanical behavior than monomethacrylate-based ones in terms of flexural strength and hardness. Fracture toughness showed no significant differences. Within the monomethacrylate group, polymethylmethacrylate showed greater flexural strength than polyethylmethacrylate.

In vivo evaluation of three-dimensional of volumetric changes using a CAD/CAM chair-side system: Technical procedure.

An intraoral digital scanner in combination with specialized three-dimensional surface analysis software monitors volumetric changes to soft tissues or dental restorations. This technology can evaluate the success of a specific technique or medium- or long-term clinical outcomes in both clinical and research situations. This article describes how this technology was used to provide immediate chair-side data analysis without the help of specialized laboratory support. Key words:Intraoral scanner, CAD-CAM, best fit-method, surface tessellation language.

Effect of retention design of artificial teeth and implant-supported titanium CAD-CAM structures on fracture resistance.

BACKGROUND: For implant-supported hybrid prostheses, high mastication forces and reduced acrylic resin thickness over a metal substructure often cause failures arising from tooth or resin fractures. To assay fracture resistance of artificial teeth and resin in implant-supported hybrid prostheses in relation to the titanium structure and retention design supporting teeth. MATERIAL AND METHODS: 40 specimens bearing incisors were divided into four groups according to the titanium structure supporting the teeth and the type of load force applied: Group I (Control; n=10): Application of static loading to ten incisors set over a metal structure with internal retention. Group II (Control; n=10): Application of static loading to ten incisors set over a metal structure with external retention. The remaining study specimens (n=20) were subjected to 120,000 masticatory and thermal cycles in a chewing simulator. Afterwards, static loading was applied until the point of fracture using an Instron machine. Group III (Study; n=10): Application of dynamic and static loading to ten incisors set over a metal structure with internal retention. Group IV (Study; n=10): Application of dynamic and static loading to ten incisors set over a metal structure with external retention. Data obtained for the four groups was analyzed and compared, determining the type of fracture (cohesive or adhesive) using a reflected light microscope. RESULTS: Statistical analysis confirmed that there were significant differences in fracture resistance between the four groups. External retention was found to have more fracture resistance than the internal retention. CONCLUSIONS: Hybrid prostheses with titanium substructures and external retention obtained significantly better results than samples with internal retention. KEY WORDS: Chewing simulator, thermocycler, fatigue, implant-supported hybrid prosthesis, acrylic teeth, fracture, metal structure design.

Chromatic appreciation in the clinic and the laboratory.

Aesthetic requirement in dentistry is getting more and more important every day. One of its basic principles is the correct selection of colour for the restorations. Colour is a quality which is modulated by a series of factors, environmental and individual, that the clinic must know. Colour measurement by the human eye can induce to an appreciation mistake if it doesn't follow a correct protocol of light conditions and observation technique, checked by the authors, simplifying it with a practical focusing. Colour measurement instruments have appeared recently, trying to correct the problems of conventional technique.

Odontología estética: apreciacion cromática en la clínica y el laboratorio / Chromatic appreciation in the clinic and the laboratory

La demanda estética en Odontología va en aumento, una de sus bases es la correcta selección del color de las restauraciones.El color es una cualidad que se ve modulada por una serie de factores ambientales e individuales que el clínico debe conocer. La valoración ocular del color, puede inducir a error de apreciación si no se sigue un protocolo correcto de iluminación, y técnica de observación los autores lo revisan, simplificándolo con un enfoque práctico. Recientemente, han aparecido instrumentos de medición del color que intentan corregir los defectos de la técnica convencional

Aesthetic requirement in dentistry is getting more and more important every day. One of its basic principles is the correct selection of colour for the restorations. Colour is a quality which is modulated by a series of factors, environmental and individual, that the clinic must know. Colour measurement by the human eye can induce to an appreciation mistake if it doesn’t follow a correct protocol of light conditions and observation technique, checked by the authors, simplifying it with a practical focusing. Colour measurement instruments have appeared recently, trying to correct the problems of conventional technique

¿Son los adhesivos dentinarios una opción válida para el tratamiento de la sensibilidad cervical dentinaria? / Are dentin bonding systems a valid option for the treatment of Cervical Dentin Sensitivity (C. D. S.)?

El objetivo de este trabajo es evaluar la capacidad in vitro de sellar túbulos dentinarios y reducir la permeabilidad dentinaria que tienen catorce productos propuestos para el tratamiento de la sensibilidad cervical dentinaria (SCD) y evaluar el efecto que la humedad y el cepillado tienen sobre ellos. Material y método: 140 discos de dentina (obtenidos de 3º molares humanos recién extraídos) se dividen en catorce grupos de 10 discos que se montan en un sistema de perfusión basado en la máquina de Pashley que mantiene una presión positiva sobre las discos. Cada disco se graba con ácido ortofosfórico al 35% y su permeabilidad se mide en una hora, este valor se considera el de referencia (100%). Un disco queda como control y se aplica tratamiento a los otros 9, midiéndose su permeabilidad en una hora. Después se deja un disco como control, a los 8 restantes se les realiza un lavado y cepillado, viéndose su permeabilidad en una hora. Resultados: Todos los productos afectaron a la perfusión dentinaria en mayor o menor grado. El cepillado de las muestras con el producto aplicado afectó a la permeabilidad, que en todas las preparaciones aumentó en mayor o menor grado. El mejor producto fue el Seal & Protect, seguido del Amm-i-dent + Xeno III, el Clearfil SE Bond y el Amm-i-dent + Scotchbond1. Conclusiones: Todos los productos presentan mala resistencia al lavado y cepillado, lo que justifica el limitado éxito clínico de los agentes desensibilizantes. El que los cuatro mejores productos o combinaciones en cuanto a reducción de permeabilidad pertenezcan al grupo de los adhesivos dentinarios indica que estos pueden ser una alternativa válida para ser investigada y perfeccionada como tratamiento de la SCD

The aim of this study is to evaluate the “in vitro” capability of fourteen agents proposed for the treatment of cervical dentin sensibility (CDS) to seal dentine tubules, to reduce dentine permeability and to resist the effect of wetness and tooth brushing. Materials and Methods: 140 dentin discs were obtained from freshly extracted human third molars. Samples were divided into fourteen groups of 10 each and were mounted in a perfusion device based on the Pashley ´s system. Each disc was etched with 35% phosphoric acid. Permeability was measured after 1 hour, this value was considered the reference value (100%). One disc was used as a control and nine were treated with a bonding system. Permeability was measured again after 1 hour. One disc was used as a control and 8 were washed with water and subjected to simulated tooth brushing equivalent to three weeks of normal brushing. Subsequebtly, permeability was measured again. Results: All systems reduced dentinal perfusion when applied. Brushing of products produced an increase of permeability. The best results were obtained with Seal & Protect, follwed by Amm-i-dent + Xeno III, Clearfil SE Bond and Amm-i-dent+Scotchbond 1. Conclusions: All products have shown low resistance to washing and brushing. This can justify unsatisfactory clinical results in reducing dentinal sensibility. The best four products were all adhesives or a combination of these, it seems to indicate that adhesives are a good choice to be investigated and improved for the treatment of CDS

¿Son los adhesivos dentinarios una opción válida para el tratamiento de la sensibilidad cervical dentinaria? / Are dentin bonding systems a valid option for the treatment of Cervical Dentin Sensitivity (C. D. S.) ?

El objetivo de este trabajo es evaluar la capacidad in vitro de sellar túbulos dentinarios y reducir la permeabilidad dentinaria que tienen catorce productos propuestos para el tratamiento de la sensibilidad cervical dentinaria (SCD) y evaluar el efecto que la humedad y el cepillado tienen sobre ellos. Material y método: 140 discos de dentina (obtenidos de 3º molares humanos recién extraídos) se dividen en catorce grupos de 10 discos que se montan en un sistema de perfusión basado en la máquina de Pashley que mantiene una presión positiva sobre las discos. Cada disco se graba con ácido ortofosfórico al 35% y su permeabilidad se mide en una hora, este valor se considera el de referencia (100%). Un disco queda como control y se aplica tratamiento a los otros 9, midiéndose su permeabilidad en una hora. Después se deja un disco como control, a los 8 restantes se les realiza un lavado y cepillado, viéndose su permeabilidad en una hora. Resultados: Todos los productos afectaron a la perfusión dentinaria en mayor o menor grado. El cepillado de las muestras con el producto aplicado afectó a la permeabilidad, que en todas las preparaciones aumentó en mayor o menor grado. El mejor producto fue el Seal & Protect, seguido del Amm-i-dent + Xeno III, el Clearfil SE Bond y el Amm-i-dent + Scotchbond1. Conclusiones: Todos los productos presentan mala resistencia al lavado y cepillado, lo que justifica el limitado éxito clínico de los agentes desensibilizantes. El que los cuatro mejores productos o combinaciones en cuanto a reducción de permeabilidad pertenezcan al grupo de los adhesivos dentinarios indica que estos pueden ser una alternativa válida para ser investigada y perfeccionada como tratamiento de la SCD (AU)

The aim of this study is to evaluate the “in vitro” capability of fourteen agents proposed for the treatment of cervical dentin sensibility (CDS) to seal dentine tubules, to reduce dentine permeability and to resist the effect of wetness and tooth brushing. Materials and Methods: 140 dentin discs were obtained from freshly extracted human third molars. Samples were divided into fourteen groups of 10 each and were mounted in a perfusion device based on the Pashley ´s system. Each disc was etched with 35% phosphoric acid. Permeability was measured after 1 hour, this value was considered the reference value (100%). One disc was used as a control and nine were treated with a bonding system. Permeability was measured again after 1 hour. One disc was used as a control and 8 were washed with water and subjected to simulated tooth brushing equivalent to three weeks of normal brushing. Subsequebtly, permeability was measured again. Results: All systems reduced dentinal perfusion when applied. Brushing of products produced an increase of permeability. The best results were obtained with Seal & Protect, follwed by Amm-i-dent + Xeno III, Clearfil SE Bond and Amm-i-dent+Scotchbond 1. Conclusions: All products have shown low resistance to washing and brushing. This can justify unsatisfactory clinical results in reducing dentinal sensibility. The best four products were all adhesives or a combination of these, it seems to indicate that adhesives are a good choice to be investigated and improved for the treatment of CDS (AU)

Influencia de la microabrasión en la fuerza de unión a esmalte de diferentes sistemas adhesivos / Influence of air abrasion on enamel bond strength of different adhesive systems

Objetivo: Comparar la fuerza de adhesión esmalte - resina, utilizando como tratamiento acondicionador: microabrasión, grabado ácido, adhesivos autograbadores y convencionales. Material y método: Se seleccionaron setenta dientes humanos, libres de caries y restauraciones. Se fabricaron las probetas y se dividieron aleatoriamente en siete grupos. Las superficies del esmalte se trataron con: (A) Microabrasión más Prompt L-Pop, (B) discos soflex y se aplicó Prompt L-Pop, (C) Prompt L-Pop, (D) microabrasión más grabado con ácido ortofosfórico 20 segundos y adhesivo (Excite), (E) microabrasión, grabado ácido 5 segundos y Excite, (F) discos soflex, grabado ácido 20 seg. y Excite. El grupo control (G): Microabrasión y Excite. A todas las muestras se colocaron cilindros de composite y luego se sometieron a las fuerzas de cizalla en una máquina Instron. Resultados: El grupo que obtuvo la mayor fuerza de adhesión, fue el grupo A, aunque no se encontraron diferencias significativas con el grupo D. El grupo que mostró el peor comportamiento fue el grupo control (G). Conclusión: La microabrasión es un procedimiento eficaz para conseguir adhesión al esmalte por si misma, pero mejora considerablemente con la técnica de grabado ácido o el uso de los sistemas adhesivos autograbadores (AU)