Accuracy of dental models fabricated by CAD/CAM milling method and 3D printing method

The purpose of this study was to evaluate the accuracy of a dental model fabricated using the CAD/CAM milling method and the 3D printing method. materials and method: this study was conducted in sequence of the digitization of the master model using an intraoral scanner, the manufacturing of working models (milling model, Multi-jet printing model and color-jet printing model) by using the scan data of the master model, the digitization of the working model by using a laboratory scanner, the superimposition of the digital data of the master model and working models using inspection software, and 3-dimensional analysis. ten measurements per group were done by one practitioner. one-way ANOVA and Tukey's post-hoc test were performed to compare the difference between the three groups. results: the overall difference in models caused by the manufacturing method was measured as 73.05µm±9.64µm, 84.52µm±4.78µm, and 96.05µm±5.43µm in the milling group, multi-jet printing group and color-jet printing group, respectively. the difference according to the shape of the teeth, the abutment teeth among the three parts was recorded with the lowest values as 19.18±2.08µm, 77.10±7.48µm, and 56.63±4.58µm. conclusions: dental models manufactured by the CAD/CAM milling method presented superior accuracy over the models manufactured by the 3D printing method. therefore, the use of optimized CAD software and appropriate materials is crucial for the fabrication accuracy of dental models.

Digital technology in fixed implant prosthodontics.

Digital protocols are increasingly influencing prosthodontic treatment concepts. Implant-supported single-unit and short-span reconstructions will benefit mostly from the present digital trends. In these protocols, monolithic implant crowns connected to prefabricated titanium abutments, which are created based on data obtained from an intraoral scan followed by virtual design and production, without the need of a physical master cast, have to be considered in lieu of conventional manufacturing techniques for posterior implant restorations. No space for storage is needed in the complete digital workflow, and if a remake is required a replica of the original reconstruction can be produced quickly and inexpensively using rapid prototyping. The technological process is split into subtractive methods, such as milling or laser ablation, and additive processing, such as three-dimensional printing and selective laser melting. The dimensions of the supra-implant soft-tissue architecture can be calculated in advance of implant placement, according to the morphologic copy, and consequently are individualized for each patient. All these technologies have to be considered before implementing new digital dental workflows in daily routine. The correct indication and application are prerequisite and crucial for the success of the overall therapy, and, finally, for a satisfied patient. This includes a teamwork approach and equally affects the clinician, the dental assistant and the technician as well. The digitization process has the potential to change the entire dental profession. The major benefits will be reduced production costs, improvement in time efficiency and fulfilment of patients' perceptions of a modernized treatment concept.

Advancements in CAD/CAM technology: Options for practical implementation.

PURPOSE: The purpose of this review is to present a comprehensive review of the current published literature investigating the various methods and techniques for scanning, designing, and fabrication of CAD/CAM generated restorations along with detailing the new classifications of CAD/CAM technology. STUDY SELECTION: I performed a review of a PubMed using the following search terms "CAD/CAM, 3D printing, scanner, digital impression, and zirconia". The articles were screened for further relevant investigations. The search was limited to articles written in English, published from 2001 to 2015. In addition, a manual search was also conducted through articles and reference lists retrieved from the electronic search and peer-reviewed journals. RESULTS: CAD/CAM technology has advantages including digital impressions and models, and use of virtual articulators. However, the implementation of this technology is still considered expensive and requires highly trained personnel. Currently, the design software has more applications including complete dentures and removable partial denture frameworks. The accuracy of restoration fabrication can be best attained with 5 axes milling units. The 3D printing technology has been incorporated into dentistry, but does not include ceramics and is limited to polymers. In the future, optical impressions will be replaced with ultrasound impressions using ultrasonic waves, which have the capability to penetrate the gingiva non-invasively without retraction cords and not be affected by fluids. CONCLUSION: The coming trend for most practitioners will be the use of an acquisition camera attached to a computer with the appropriate software and the capability of forwarding the image to the laboratory.

Gingival displacement for impression making in fixed prosthodontics: contemporary principles, materials, and techniques.

The clinical success and longevity of indirect restorations depend on the careful and accurate completion of several procedures. One of the challenging procedures is management of the gingival tissues and gingival esthetics. The goal for management of gingival tissues and gingival esthetics is to maintain the normal appearance of healthy gingival. Achieving this goal requires optimal health before treatment and minimal trauma during treatment. The best way of optimizing health and minimizing trauma is to avoid contacting the gingiva with restorative materials.

Avaliação da rugosidade superficial com técnicas de moldagem de silicones de condensação sobre influência da desinfecção química / Evaluation of the superficial roughness of condensation silicones, using impression techniques, influenciaded by chemical disinfection

A proposta deste estudo foi avaliar a rugosidade superficial de duas técnicas de moldagem com dois silicones de condensação (Zetaplus-Zhermack e Clonage-DFL) densos e fluídos sobre a influência da desinfecção química com solução à base de clorexidina 2 por cento (aspersão por 5 minutos). Foram confeccionados 56 corpos de prova que foram divididos em 8 grupos, sendo que metade foi submetido à desinfecção com solução a base de clorexidina 2 por cento antes das leituras do teste de dureza. Os corpos de prova foram submetidos ao ensaio de rugosidade superficial com auxílio de um rugosímetro digital (modelo RP100). Para cada corpo de prova, foram realizadas três leituras em diferentes sentidos e, transformadas em valores médios e analisados através de modelo de análise da variância e as médias comparadas pelo teste de Tukey (p>0,05). Não houve diferença estatisticamente significativa quando analisado os tipos de materiais utilizados independentemente da técnica de desinfecção química e houve diferença estatisticamente significativa quando analisado a técnica e desinfecção química independentemente das outras variáveis.

Trends in elastomeric impression materials.

In the past three years more addition silicones have been supplied as hydrophilic materials and heavier viscosities have been provided in automatic mixing cartridges. Also, a polyether is now supplied in an automatic mixing system. There has been an increase in the number of products available as monophase or single viscosity systems. Both addition silicones and polyethers are available as bite registration materials.