A review of CAD/CAM use in dentistry (part II): Comparison of intraoral digital scanners used in restorative dentistry

Introduction: Intraoral imaging technology has become one of the most exciting new fields in dentistry. Three-dimensional scanning of the oral cavity is used in many dental procedures such as restorative dentistry and orthodontics. To date, a number of intraoral scanners have been developed for restorative dentistry throughout the world, and many researchers and manufacturers seek the design and development of new digital devices. Only some of these devices are currently available on the market and some others are being clinically tested. All existing intraoral scanners try to overcome the drawbacks of traditional impression processes. The aim of the present article is to provide an extensive evaluation of intraoral scanners in restorative dentistry, with special attention to their assessment principles, characteristics and performance. Review report: This review article was prepared by scientific searching in electronic sources of Pubmed and ISI Web of Science in connection with articles published in English until 2014, and with these key words: intraoral scanners and digital impression. Conclusion: Over the years there have been major advances in digital scanning systems, and a variety of digital systems have been introduced that enable the dentist to select different intraoral reconstruction methods in the extraoral environment. The ultimate goal of dentists is to provide accurate and efficient dental restorations for the patient, while maintaining patient comfort during the impression process. High-resolution dental optical scanners will enable the operator to provide high-quality restorations. With digital impression techniques, the number of operators and material variables will decrease, making restoration fabrication processes more predictable and easier

The ratio of the interzygomatic width with mesiodistal width of maxillary anterior teeth

Esthetics is one of the prosthetic treatment goals. Correct selection of anterior teeth, regarding size and appearance, results in a successful treatment. The goal of the present research was to investigate the relationship between interzygomatic width and maxillary anterior teeth width in order to find a better determinant for artificial anterior teeth selection. In this study, the interzygomatic width and maxillary central incisors width and also the width of six maxillary anterior- teeth, in 71 subjects (29females and 42 males) were measured. The results showed a significant difference in maxillary anterior teeth width, comparing men and women, (P<0.05). These measurement in people under study, are less than Europeans. The interzygomatic width was also more in men than women (PO.05), which is, less than of European race. The ratio between interzygomatic and central maxillary incisor width was 15:1 which is less than 16:1 that is used in clinic. Thus, it is recommended to pay more attention to anterior teeth selection, especially in young patients

Average annual crestal bone loss of ITI implants following the first year of loading

BACKGROUND: Long term success of dental implants directly depends on marginal bone resorption. The aim of this study was to determine the annual average bone loss on the mesial and distal aspects of implants following the first year of implantation.
 METHODS: This was a descriptive analytical study of patients treated with ITI (International Team of Implantology) implants at the Dental School of Isfahan University of Medical Sciences from 1998-2002 (1377-81). A total of 15 patients with 41 implants were selected by convenience sampling method. The height of the alveolar bone was measured using panoramic radiography before and after loading with calipers to determine the average bone loss. Other information such as pocket depth, bleeding index, plaque index, gingival recession, was obtained by clinical examinations. The mean bone loss on the mesial & distal sides was analyzed by ANOVA at 0.05 level of significance.
 RESULTS: The average bone loss on the proximal sides of ITI implants obtained annually after the first year of loading was 0.084 ± 0.035 mm with slight difference on the mesial (0.092 ± 0.035) and distal (0.072 ± 0.033) sides. There was negligible difference between male and female patients. The average survival rate for thirty three months was 95.1%.
 CONCLUSION: The average bone loss on the mesial and distal sides of ITI implants compared with other studies was satisfactory. Survival and success rates were acceptable.
 KEYWORDS: Dental implants, bone resorption, survival rate, dental plaque index

An Investigation on Metallic Ion Release from Four Dental Casting Alloys

Statement of Problem: Element release from dental casting alloys into the oral environment is of clinical concern and is considered to be a potential health problem to all patients.Purpose: The aim of this study was to investigate the metallic ion release of four base metal alloys.Materials and Methods: Two Ni-Cr (Minalux and Supercast) and two Co-Cr alloys (Minalia and Wironit) were examined. Nine specimens of each type were prepared in 13×11×1.4 mm dimensions and each of the four alloys (3 specimens per group) were conditioned in artificial saliva at 37 c for one, three and seven days.The conditioning media were analyzed for element-release using Inductive CoupledPlasma Atomic Emission Spectrophotometer (ICPAES). Collected data were statistically analyzed using ANOVA and Duncan multiple range test (P< 0.05).Results: The greatest amount of element release was seen after seven days (134.9 ppb Supercast, 159.2 ppb Minalux, 197.2 ppb Minalia, and 230.2 ppb Wironit). There was a significant difference between the released elements from the alloys after the three conditioning times (p<0.001).Conclusion: Element release from the studied alloys is proportional to the conditioning time. The Ni-Cr alloys tested in this investigation were more resistant to corrosion as compared to the Co-Cr alloys in artificial saliva. Supercast had the highest corrosion resistance

An evaluation on the adherence of Candida albicans to different denture- base materials

The surface topography of denture base material is an important factor for the&quot;nadhesion of Candida albicans and other microorganisms.&quot;nPurpose: The aim of this study was to evaluate the adherence of Candida albicans to four types of denture&quot;nbase materials (Acropars acrylic resin, Meliodent acrylic resin, rough and smooth surfaces of Molloplast B).&quot;nMaterials and Methods: Seven blocks of two types of acrylic resins and ten blocks of silicone with one&quot;nrough and one smooth surface were made and incubated in a suspension of Candida albicans. After washing,&quot;nthe blocks were stained with acridine orange and examined under fluorescent microscope. For statistical&quot;nanalysis ANOVA and Duncan tests were used.&quot;nResults: It was observed that Candida adhesion to rough surfaces of acrylic resins and silicone was&quot;nsignificantly more than polished surfaces of acrylic resins and smooth silicone (PO.0001). However, no&quot;nstatistical significant difference was found between polished acrylic resins surfaces and smooth silicone.&quot;nConclusion: Significant differences in the adherence of Candida to the surfaces of different denture base&quot;nmaterials are due to differences in surface topography, chemical, physical and hydrophobic properties so it is&quot;nrecommended to minimize the roughness and irregularities of denture base

Developing a software for removable partial denture design: Part I: Data collection

Background and Aim: Proper designing of partial denture frameworks is the duty of dentists, but this task is often abdicated to technicians because of lack of time and experience. Computer assisted learning and designing can be used for both training dental students and helping dentists design proper frameworks. As the first step to prepare software for framework designing, this study evaluated the agreement on different framework designing principles, among prosthodontists of dental schools in Iran. &quot;nMaterials and Methods: A questionnaire consisting of 121 design rules was sent to 41 prosthodontists at seven dental schools in Iran .The percentage rate of agreement on results was used for data analysis. &quot;nResults: The percentage of rules accepted by more than 60% of the prosthodontists was 76.2%. It consisted 80% saddle rules, 76.2% rest rules, 78.4% clasp rules, 63.6% maxillary major connector&apos;s rules and 80.9% mandibular major connector rules. &quot;nConclusion: The percentage of accepted rules by Iranian prosthodontists was 76.2%. Maxillary major connectors had the least acceptance

An overview of application of CAD/CAM in dentistry (Part I)

Introduction: Today, new developments in the field of computer hardware and software have led to the production of advanced equipment and devices in industry, including the dental field. One of these devices is computer-aided design (CAD) and computer-aided manufacture (CAM) system. CAD/CAM systems are able to collect data and design and manufacture a wide range of dental restorations such as inlays, onlays, veneers, crowns, fixed partial dentures, orthodontic appliances and dental implant abutments. The aim of this article is to review the history of CAD/CAM, types of available CAD/CAM systems, how they function and application concepts in digital dentistry. Article description: This article was collected by scientific search in electronic resources, books, Pubmed and ISI Web of Science websites, in articles published in English until 2013, and with the following key words: history, advantages and disadvantages, an overview of the components and the performance of CAD/CAM systems in dentistry. Conclusions: In recent years, digital technology is advancing rapidly in dentistry and now it can be applied to almost any restorative situation, including full-mouth rehabilitation. Computer technology has made fabrication of restorations easier, faster, cheaper and more predictable than before. While there are many benefits for dental digital systems, it is necessary for the dental team to master their function in order to maximize their advantages for creating well-fitting restorations