Complete assessment of occlusal dynamics and establishment of a digital workflow by using target tracking with a three-dimensional facial scanner

Purpose

To introduce a new and simple digital workflow to record dynamic occlusion, and apply it to occlusal analysis and prosthetic treatment in a virtual environment.

Evaluation of a portable low-budget three-dimensional stereophotogrammetry system for nasal analysis

Background

Three-dimensional (3D) photogrammetry has reached high standards and accuracy but is mainly conducted with stationary and expensive systems. The purpose of this study was to evaluate the accuracy of a low-budget portable system with special regard to the gracile and challenging nasal region.

Digital impression and jaw relation record for the fabrication of CAD/CAM custom tray

Purpose

This article describes the protocol of a digital impression technique to make an impression and recording of the jaw relationship of edentulous patients for the fabrication of CAD/CAM custom tray using computer-aided design and manufacturing (CAD/CAM) technology.

Three-dimensional trueness analysis of ceramic crowns fabricated using a chairside computer-aided design/manufacturing system: An in vitro study

PurposeThis study analyzed the trueness of polymer-infiltrated ceramic and glass ceramic crowns manufactured using the chairside computer-aided design/manufacturing (CAD/CAM) system.MethodsThe master model designs crowns using a CAD program after acquiring a digital impression with an intraoral scanner. Vita Enamic (VE), Vita Suprinity (VS), and IPS e.max CAD (IPS) were used to manufacture 10 crowns each (total: 30 crowns), using the chairside CAD/CAM system (inLab MC XL). Trueness was evaluated by superimposing the CAD data on the scan data using a three-dimensional program. The Kruskal–Wallis H test, a nonparametric test, and the Mann–Whitney U test were performed by applying the significance level (0.05/3 = 0.016), which was adjusted by post-analysis Bonferroni testing.ResultsThere was a significant difference in the trueness between the samples (p < 0.05). However, there was no statistically significant difference in the outer surface trueness between the samples (p > 0.05).ConclusionsThese findings show that the milling accuracy of VE is better than that of VS and IPS.     

数字化口腔修复（20）--数字化全口覆盖义齿的临床应用（附病例报告）

目的：利用计算机辅助设计与制造（ computer aided design／computer aided manufacturing,CAD／CAM）技术,制作数字化的全口覆盖义齿并评价其修复效果。方法：临床病例为上下颌各残余经根管治疗和金属根帽修复的两个残根的无牙颌患者,按照传统全口义齿的临床操作完成印模,哥特式弓记录轨迹,面弓转移牙合记录,上牙合架,再经过扫描牙合架上的模型,在CAD虚拟牙合架上完成虚拟排牙和虚拟咬合运动,CAM切削基托蜡型和成品人工牙,最后将人工牙安放在切削基托蜡型咬合面的基底上。经过传统试排牙和三维数字化试排牙后,患者满意后,常规充胶,完成全口覆盖义齿制作并戴牙。结果：数字化全口覆盖义齿的固位和稳定良好,美观,能够正常行使咀嚼功能。结论：数字化全口覆盖义齿与传统的全口覆盖义齿比较,具有简单数字化排牙工艺,牙合设计精确,形成的牙合曲线完美,基托厚薄一致,患者适应期短的优点,是今后全口义齿制作的发展方向。     

A fully digital approach to replicate functional and aesthetic parameters in implant-supported full-arch rehabilitation

Purpose

The aim of this technical procedure was to use a fully digital technique (FDT) for full-arch implant support rehabilitation. The FDT was used to transfer the provisional restoration parameters to definitive restorations using intraoral scanners.

The effect of ceramic thickness and number of firings on the color of a zirconium oxide based all ceramic system fabricated using CAD/CAM technology

PURPOSE

Ceramics have a long history in fixed prosthodontics for achieving optimal esthetics and various materials have been used to improve ceramic core strength. However, there is a lack of information on how color is affected by fabrication procedure. The purpose of this study was to evaluate the effects of various dentin ceramic thicknesses and repeated firings on the color of zirconium oxide all-ceramic system (Lava™) fabricated using CAD/CAM technology.

MATERIALS AND METHODS

Thirty disc-shaped cores, 12 mm in diameter with a 1 mm thickness were fabricated from zirconium oxide based all ceramic systems (Lava™, 3M ESPE, St Paul, MN, USA) and divided into three groups (n = 10) according to veneering with dentin ceramic thicknesses: as 0.5, 1, or 1.5 mm. Repeated firings (3, 5, 7, or 9) were performed, and the color of the specimens was compared with the color after the initial firing. Color differences among ceramic specimens were measured using a spectrophotometer (VITA Easyshade, VITA Zahnfabrik, Bad Säckingen, Germany) and data were expressed in CIELAB system coordinates. A repeated measures ANOVA and Bonferroni post hoc test were used to analyze the data (n = 10, α=.05).

RESULTS

L*a*b* values of the ceramic systems were affected by the number of firings (3, 5, 7, or 9 firings) (P<.001) and ceramic thickness (0.5, 1, or 1.5 mm) (P<.001). Significant interactions were present in L*a*b* values between the number of firings and ceramic thickness (P<.001). An increase in number of firings resulted in significant increase in L* values for both 0.5 mm and 1.5 mm thicknesses (P<.01, P=.013); however it decreased for 1 mm thickness (P<.01). The a* values increased for 1 mm and 1.5 mm thicknesses (P<.01), while it decreased for 0.5 mm specimens. The b* values increased significantly for all thicknesses (P<.01, P=.022). As the dentin ceramic thickness increased, significant reductions in L* values (P<.01) were recorded. There were significant increases in both a* and b* values (P<.01) as the dentin ceramic thickness increased.

CONCLUSION

The number of firings and dentin ceramic thickness have a definite effect on the final color of all ceramic system tested. The mean ΔE value increased as the dentin ceramic thicknesses increased for zirconium-oxide based all ceramic specimens tested. However, the mean ΔE values were less than 3.7ΔE units which is rated as a match in the oral environment.     

A Digital Approach to Retrofitting a Post and Core Restoration to an Existing Crown

One problem that may arise in full‐coverage restorations is clinical crown fracture. Fracture of an endodontically treated and crowned tooth in the esthetic zone may be embarrassing to both the patient and clinician. If a completely sound margin and at least 2 mm of coronal structure remain, a fractured tooth may possibly be retreated by a repair. Several methods have been introduced to reproduce the original contour of the tooth for retrofitting an existing crown. If an existing crown is used as a template, excessive core material may remain over the margin, as loading the proper amount of core material is difficult, and making vent holes on the existing crown is not feasible. This article presents a repair technique to reuse an existing crown with computer‐aided design and computer‐aided manufacturing (CAD/CAM) technology. By using a milled poly(methylmethacrylate) matrix, the mentioned limitations are eliminated, and the original contour of the tooth can be effectively restored with minimal intervention. As an existing crown is reused, the issues of additional time and cost for repreparation, reimpression, and new crown are eliminated.     

Marginal and internal discrepancies related to margin design of ceramic crowns fabricated by a CAD/CAM system

Purpose: The aim of this study was to evaluate the marginal discrepancy (MD) and internal discrepancy (ID) of ceramic crowns manufactured by a CAD/CAM system, having different finish lines. The hypotheses tested were that the finish line type would not influence the MD or ID of the crowns, and ID would not change in different regions. Materials and Methods: Three aluminum master dies (height: 5.5 mm, Ø: 7.5 mm, conicity: 6°) with different finish lines (TC: tilted chamfer; LC: large chamfer; RS: rounded shoulder) were manufactured. Ten impressions were made from each master die using a modified parallelometer. Impressions were poured in type IV dental stone, and 30 ceramic crowns (IPS Empress CAD, Ivoclar) were subsequently milled. The crowns were fixed on their respective metallic die using a metallic fixation device. The distance between the external edges of the crown to the edge of the cervical preparation was performed at 50 points on the respective metallic die (MD analysis). With the replica technique, the ID values of each crown were further evaluated at 12 points equidistant to each other in three regions: radius (R), axial (A), and occlusal (Occl). The measurements were performed using an optical microscope (250×). The data (μm) were analyzed using ANOVA and Tukey′s test (5%). Results: The RS group (28.24 ± 11.42 μm) showed significantly lower MD values (p= 0.001) than those of TC (99.92 ± 18.32 μm) and LC (64.71 ± 25.64 μm) groups, both of which also differed statistically from one another. The ID results demonstrated significantly lower values in the LC group (183.01 ± 62.82 μm) (p= 0.0014) than those of TC (216.26 ± 83.23 μm) and RS (219.12 ± 87.24 μm) groups. ID results of TC and RS were not significantly different. Additionally, the ID results showed significant differences among the regions (p= 0.0001). The null hypotheses were rejected. Conclusion: The RS finish line produced MD values significantly lower than tilted and large chamfer, but large chamfer presented the lowest internal discrepancy values. Independent of the finish line type, internal discrepancy was the lowest in the axial region followed by radius and occlusal regions.     

Computer-assisted surgery for reconstruction of complex mandibular defects using osteomyocutaneous microvascular fibular free flaps: Use of a skin paddle-outlining guide for soft-tissue reconstruction. A technical report

Introduction

We present our pre-operative virtual planning of complex mandibular reconstruction with a microvascular fibular composite free flap and its harvesting using our novel cutaneous positioning guide based on the perforator vessels for our soft tissue reconstructive surgery.

Surgical treatment of a skeletal Class III patient using customized brackets based on the CAD/CAM virtual orthodontic system

The computer-aided design/computer-aided manufacturing (CAD/CAM) virtual orthodontic system produces customized brackets, indirect bonding jigs, and archwires based on a three-dimensional virtual setup. In surgical cases, this system helps to visualize the final occlusion during diagnosis and to efficiently plan individualized presurgical orthodontic treatments. A 20-year-old female patient with a skeletal Class III malocclusion, maxillary protrusion, and lip protrusion was successfully treated with orthognathic surgery and orthodontic treatment with maxillary first premolar extractions. The CAD/CAM system was applied for efficient treatment, with a total active treatment time of 16 months. In this case report, the applicability of the CAD/CAM virtual orthodontic system for orthognathic surgery cases is demonstrated. Suggestions are also made to overcome the limitations and to maximize the advantages of this system during orthodontic treatment of patients undergoing orthognathic surgery.     

Surgical and Prosthodontic Treatment of a Patient with Significant Trauma to the Middle and Lower Face Secondary to a Gunshot Wound: A Clinical Report

Large defects of dentofacial structures may result from trauma, disease (including neoplasms), and congenital anomalies. The location and size of the defects are related to difficulties that patients report relative to speech, mastication, swallowing, facial esthetics, and self-image. This article reports on the evaluation and treatment of a patient who suffered significant trauma to the lower and mid-face secondary to a gunshot injury. It describes the initial presentation, life-saving procedures, and subsequent bone grafts, implant placement, and prosthetic treatments required to rehabilitate the patient to a condition that closely approximated his preoperative condition. This clinical report confirms that no matter the degree of complexity involved in treating the results of significant facial trauma, successful treatment is dependent on thorough physical and radiographic examinations, development of the appropriate diagnoses, and treatment based on sound prosthodontic and surgical principles.