Fit Accuracy of Removable Partial Denture Frameworks Fabricated with CAD/CAM, Rapid Prototyping, and Conventional Techniques: A Systematic Review.

OBJECTIVE: Analyzing and comparing the fit and accuracy of removable partial denture (RPDs) frameworks fabricated with CAD/CAM and rapid prototyping methods with conventional techniques. MATERIALS AND METHODS: The present systematic review was carried out according to PRISMA guidelines. The search was carried out on PubMed/MEDLINE, Cochrane collaboration, Science direct, and Scopus scientific engines using selected MeSH keywords. The articles fulfilling the predefined selection criteria based on the fit and accuracy of removable partial denture (RPD) frameworks constructed from digital workflow (CAD/CAM; rapid prototyping) and conventional techniques were included. RESULTS: Nine full-text articles comprising 6 in vitro and 3 in vivo studies were included in this review. The digital RPDs were fabricated in all articles by CAD/CAM selective laser sintering and selective laser melting techniques. The articles that have used CAD/CAM and rapid prototyping technique demonstrated better fit and accuracy as compared to the RPDs fabricated through conventional techniques. The least gaps between the framework and cast (41.677 ± 15.546 µm) were found in RPDs constructed through digital CAD/CAM systems. CONCLUSION: A better accuracy was achieved using CAD/CAM and rapid prototyping techniques. The RPD frameworks fabricated by CAD/CAM and rapid prototyping techniques had clinically acceptable fit, superior precision, and better accuracy than conventionally fabricated RPD frameworks.

The Development of Nonanatomic Denture Occlusion: Part III.

Part III of this four-part series about nonanatomic denture tooth development traces the evolution of this movement from the mid-1930s through the World War II era up to the early 1950s. By this time, the general preference for posterior denture occlusion had shifted from anatomic to nonanatomic teeth, and all the major denture tooth manufacturing companies listed at least one nonanatomic design in their inventories.

The Development of Nonanatomic Denture Occlusion: Part IV.

This fourth and final part of a four-part series concerned with the development of nonanatomic denture occlusion follows nonanatomic tooth design from the time of Victor Sears' first nonanatomic tooth patent through the end of the 20th century. Part IV concentrates on nonanatomic teeth developed during the last five decades of the 20th century. Many of the designs featured in this series exhibited genius, while others are pure nonsense. Sears claimed that a new nonanatomic tooth design appeared every 9 months on average during the first 30 years of nonanatomic tooth production. Many current nonanatomic tooth patents are further refinements of those earlier designs.

The Development of Nonanatomic Denture Occlusion: Part II.

This second part of a four-part series concerned with the development of nonanatomic denture occlusion follows nonanatomic tooth design from the time of Victor Sears' first nonanatomic tooth patent through the mid-1930s. Many of the designs featured in this series exhibit genius, while others are pure nonsense. Sears claimed that a new nonanatomic tooth design appeared every 9 months on average during the first 30 years of nonanatomic tooth production. Many current nonanatomic tooth patents are further refinements of those earlier designs. Part II reviews pioneering designs that appeared during the first dozen or so years of this paradigm shift in denture occlusion philosophy.

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.

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.

Removable partial dentures: clinical concepts.

This article provides a review of the traditional clinical concepts for the design and fabrication of removable partial dentures (RPDs). Although classic theories and rules for RPD designs have been presented and should be followed, excellent clinical care for partially edentulous patients may also be achieved with computer-aided design/computer-aided manufacturing technology and unique blended designs. These nontraditional RPD designs and fabrication methods provide for improved fit, function, and esthetics by using computer-aided design software, composite resin for contours and morphology of abutment teeth, metal support structures for long edentulous spans and collapsed occlusal vertical dimensions, and flexible, nylon thermoplastic material for metal-supported clasp assemblies.

The use of CAD/CAM in dentistry.

Computer-aided design (CAD) and computer-aided manufacturing (CAM) have become an increasingly popular part of dentistry over the past 25 years. The technology, which is used in both the dental laboratory and the dental office, can be applied to inlays, onlays, veneers, crowns, fixed partial dentures, implant abutments, and even full-mouth reconstruction. This article discusses the history of CAD/CAM in dentistry and gives an overview of how it works. It also provides information on the advantages and disadvantages, describes the main products available, discusses how to incorporate the new technology into your practice, and addresses future applications.

Treatment planning for replacing missing teeth in UK general dental practice: current trends.

The aim of this study was to examine the confidence, barriers and attitudes towards the replacement of missing teeth by general dental practitioners (GDPs). The perceived impact of the recently introduced National Health Service (NHS) contract on the provision of prosthodontic treatments was also considered. Pre-piloted postal questionnaires were mailed to 500 GDPs in Wales. Open- and closed-ended questions were utilised to establish confidence, adequacy of training and attitudes towards treatments for replacing missing teeth. Two hundred and seventeen completed questionnaires were received (response rate = 43.4%). Many respondents described themselves as 'confident' or 'very confident' in the provision of removable partial dentures (RPDs) (acrylic = 100%, metal based = 99.5%), cantilever resin-bonded bridges (94.4%) and conventional bridgework (98.6%). GDPs were 'not confident' providing fixed-fixed resin-bonded bridges (21.1%) or implants (81.4%). Financial barriers were identified to the provision of prosthodontic treatments, including comments such as "the new [National Health Service] contract does limit the treatments available". Privately funded patients were more likely to be offered a fixed bridge or implant replacement of a missing upper first molar, whereas non-privately funded patients were more likely to be offered no treatment (P < 0.01). Most respondents reported confidence at providing more routine forms of prosthodontic care such as RPDs and bridges. It appears that funding arrangements may have an impact on treatments offered to replace missing teeth, particularly under the current NHS contract.

Contemporary techniques for denture fabrication.

This article reviews the fabrication of complete dentures and presents findings of recent technological studies that have relevance to current complete denture practice. In addition, summaries of two recent randomized controlled studies demonstrate the need for more deliberate prescription of impression materials.

A review of dental CAD/CAM: current status and future perspectives from 20 years of experience.

In this article, we review the recent history of the development of dental CAD/CAM systems for the fabrication of crowns and fixed partial dentures (FPDs), based on our 20 years of experience in this field. The current status of commercial dental CAD/CAM systems developed around the world is evaluated, with particular focus on the field of ceramic crowns and FPDs. Finally, we discuss the future perspectives applicable to dental CAD/CAM. The use of dental CAD/CAM systems is promising not only in the field of crowns and FPDs but also in other fields of dentistry, even if the contribution is presently limited. CAD/CAM technology will contribute to patients' health and QOL in the aging society.

Immediate Occlusal Loading (IOL) of dental implants: predictable results through DIEM guidelines.

For years, dental implants have been loaded immediately upon implant placement with varying degrees of success. As clinicians' understanding of the biological and mechanical factors involved in immediate occlusal loading (IOL) has evolved, the success of these procedures has increased--particularly as a treatment option for the restoration of the edentulous mandible or the mandible that will be rendered edentulous during treatment. Due to increasing interest in this treatment alternative, the authors have provided a clear definition of the terminology associated with IOL and have demonstrated the DIEM Guidelines used to increase the success and predictability of such treatment. This presentation also introduces new implant components that simplify the clinical application of the immediate loading concept, enhancing its benefits and acceptance among dental patients and practices alike.

The comparison of usefulness prosthetic rehabilitation with removable and fixed suprastructures on endosseous implants.

Advanced atrophy bone in edentulous jaws is a serious problem for conventional prosthodontics. The advent of implantology, as well as guided reconstruction of bones, has opened new possibilities for conventional prosthodontic suprastructures. The turning point in implantology occurred in the sixties and was promoted by a Swedish orthopaedist Brånemark. Nowadays, implants are inserted routinely without creating any significant problems to a skillful maxillofacial surgeon. This study was performed in 73 patients who had 77 prosthodontic suprastructures (fixed suprastructures in 58 and removable in 15 patients) placed on a total of 331 implants. Three types--blade, cylindrical and screw implants, were used. Patients with both total and partial defects had typical removable and fixed suprastructures installed. All patients were followed radiologically and clinically. Pantomographic images taken at different stages of the study served to measure bone atrophy near the implants. The atrophy of bones near implants supported by removable prosthodontic suprastructures was compared with fixed suprastructures. Dental bridges were made and supported by implants and by the patient's own teeth at the same time. Removable suprastructures, however, were supported mainly by implants connected with bars or implants with ball attachments. The prothesis saddle rested on the epithelium of the oral cavity. Following location of the implants, lower and upper jaws were divided into four regions. Statistical data served to determine in which of the four regions atrophy of bones was most and least advanced taking into consideration the type of implant and type of prosthodontic suprastructure. Record was made of the region, stage and implant which underwent explantation. Radiographs taken before and after implantoprosthetic rehabilitation demonstrated that atrophy of bones did not occur in 106 cases. Six patients underwent reconstruction of bones near the implants. Statistics showed that fixed prosthodontic suprastructures are superior to removable as far as jaw rehabilitation is concerned. Atrophy of bones near implants supported by fixed suprastructures was smaller. Nevertheless, usefulness of the removable suprastructures cannot be questioned. Not only do they represent an effective solution, but are far less expensive than fixed. Statistics revealed that the best regions to install implants include the presinusal (I) and interforaminal regions (II). The least advanced atrophy of bones occurred near screw implants (0.8 mm in region I, 0.7 mm in region II, 0.3 mm in subantal region (III) and 1.3 mm in postforaminal region (IV)). On the other hand, the most advanced atrophy occurred near blade implants (1.7 mm in region III and 3.3 mm in region IV). Twelve out of 331 implants were lost (3.6%)--seven during the healing process and five after placement of suprastructures (all cylindrical), contributing to successful implantoprosthetic therapy in 96.4% of cases. One out of twelve implants was lost in the mandible and eleven in the maxilla indicating that the mandible is more suitable for implantation. On the basis of this prospective study it can be concluded that further progress in implantoprosthetics, a relatively new branch of dentistry, will open new possibilities for prosthetic therapy.

The results of a brief survey of complete denture prosthodontic techniques in predoctoral programs in North American dental schools.

A brief mail survey of North American dental schools was undertaken to ascertain the current techniques in complete denture prosthodontics regarding preliminary and final impressions, record bases, and denture teeth. Of the 64 schools surveyed, 54 responded (84%). Seventy-four percent of the respondents used only irreversible hydrocolloid (alginate) for their preliminary impressions; 15% used only modeling plastic impression compound. Eighty-one percent used only modeling plastic impression compound for border molding of the final impression tray; 7% used only polyether impression material. Forty-eight percent used only polysulfide rubber (PR) impression material for their final impression material; 4% used only polyether impression material. Only 1 school still used shellac as one of its materials for record bases. Thirty-five percent used only Triad; 35% used only acrylic resin; 24% used both of these materials. Thirteen percent of responding schools used only nonanatomic teeth. The majority (54%) used all three options (nonanatomic, semianatomic, and anatomic). Eleven percent used lingualized occlusion. As compared with a survey performed in 1985, the use of irreversible hydrocolloid as a preliminary impression material, the use of visible light-cured resins for record bases, and the use of anatomic teeth have increased. The use of plastic impression compound for border molding and PR as the final impression material has largely remained the same.

CAD/CAM in dentistry: a historical perspective and view of the future.

What can we look forward too? Lots of fun with new CAD/CAM systems that will enhance dentistry, providing quality restorations quickly. The evolution of an array of new versions of already available systems as well as altogether new systems will provide improved quality, expanded capabilities, and increasing user friendliness. And new materials will be more esthetic, wear more nearly like enamel, and strong enough for full crowns and bridges. We can also look forward to lots of change. Because of the cost of CAD/CAM systems, many clinicians are likely to collaborate by sharing a single system. Laboratories and clinicians may collaborate as well, with data being gathered in the operatory and sent to a laboratory via modem. The fabrication would then be done by the laboratory. Other changes that we cannot even predict are likely to occur in dentistry. Exciting times are here. Automation through dental CAD/CAM systems will, most certainly, change the profession. The impact of that change will only be known in the future. But as the future approaches, the systems and materials available to us will continue to evolve, improve, and enhance dentistry.