Fixed Rehabilitation of an ACP PDI Class III Patient

This clinical report documents the treatment of a 63-year-old Caucasian female Prosthodontic Diagnostic Index Class III patient using dental implants and a fixed prosthetic reconstruction. The treatment involved the fabrication of single crowns and fixed partial dentures retained by natural teeth in the maxillary arch. The posterior segments of the mandibular arch were rehabilitated with fixed partial dentures retained by endosseous implants.     

CAD/CAM systems,materials, and clinical guidelines for all-ceramic crowns and fixed partial dentures

Advances in dental ceramic materials and the development of computer-aided design/computer-aided manufacturing (CAD/CAM) and milling technology have facilitated the development and application of superior dental ceramics. CAD/CAM allows the use of materials that cannot be used with conventional dental processing techniques. This article reviews the main techniques and new materials used in dentistry for CAD/CAM-generated crowns and fixed partial dentures. Also covered are the clinical guidelines for using these systems.     

A comparison of fixed prostheses generated from conventional vs digitally scanned dental impressions

For many years, mechanical and laser-based scanning technology has been used with computer-aided design and computer-aided manufacturing applications in the field of dentistry, but most have been limited to the dental laboratory. For the past 20 years, only 1 intraoral scanning device has been available to the dentist for in-office use. Recently, a new kind of intraoral scanning technology was introduced to the dental market. This technology, based on a laser scanning protocol called "parallel confocal," allows the dentist to take electronic impressions intraorally. This technology is coupled with traditional laboratory protocol for the construction of fixed dental restorations, providing the dentist with an accurate and efficient system to produce high-quality fixed dental restorations of all types. In a blind study, crowns developed using this technology were preferred over crowns generated using conventional impressions and criteria of marginal fit, contacts, occlusion, and time of adjustment in nearly 70% of cases. This article introduces scanning technology including a discussion of its clinical applications and an overview of the benefits.     

Dental implants: materials and design

The use of endosseous dental implants represents one of the most rapidly expanding areas of dentistry. This article attempts to summarize the current understanding of factors affecting dental implant success. The need continues for further fundamental studies to provide a base for future improvements in the design and use of dental implants.     

Immediate placement of implants in extraction sites of maxillary impacted canines

BACKGROUND: Treatment of asymptomatic impacted maxillary canines in adults is inevitable when primary canine becomes lost through extraction or exfoliation or when the impacted tooth becomes symptomatic. Treatment alternatives include an orthodontic procedure to bring the unerupted tooth to the dental arch or prosthetic replacement of the missing tooth. The authors describe an alternative treatment that involves immediate placement of implants into extraction sockets of the teeth. CASE DESCRIPTION: A patient with bilateral palatally impacted upper canines chose to have the unerupted teeth removed and replaced with implants and crowns. Two hydroxyapatite cylindrical implants were inserted through the alveolar ridge into the extraction sites. The unfilled areas in the extraction sites, around the dental implants, were packed and covered with demineralized freeze-dried bone allograft in conjunction with a collagen membrane barrier. Six months after implantation, computed tomography revealed complete osseous fill of the extraction defects and no bone loss around the implants. The implants were uncovered, and porcelain-fused-to-metal restorations were fabricated and placed. CLINICAL IMPLICATIONS: This treatment modality avoids the need for conventional preparation of teeth as part of prosthetic reconstruction or prolonged orthodontic treatment aimed at bringing the impacted canine to the dental arch. Combining the implantation with bone augmentation preserved the alveolar bone and shortened the treatment period.     

Glass fiber-reinforced abutments for dental implants. A pilot study

Titanium abutments in dental implants shine through all-ceramic crowns and therefore limit excellent esthetic results. Prototypes of tooth-colored fiber-reinforced abutments were investigated to avoid the shining-through effect. In vitro, the fracture strength was determined after thermal cycling and mechanical loading of all-ceramic single crowns and four-unit bridges made of a fiber-reinforced composite. The suprastructures were adhesively fixed onto fiber-reinforced implant abutments and compared with those fixed on standard titanium abutments. The median of the fracture strength of the titanium-supported all-ceramic crowns was significantly higher than the median of crowns fixed onto the prototypes. But this value was still more than twice as high as the maximum loading force under oral conditions. No statistical difference was found between four-unit bridges made by fiber-reinforced composite inserted onto titanium abutments and those inserted onto fiber-reinforced abutments. Fiber-reinforced abutment prototypes for dental implants avoided the shining-through effect associated with metal abutments. Their load-bearing capacity after in vitro stress simulation was higher than the maximum oral loading force. With some improvements, the fiber-reinforced implant abutments are therefore a promising alternative to titanium abutments.     

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.     

Implant positioning when replacing the four maxillary incisors: a platform-switched treatment option

Patients do not view dental implants as an object of desire but seek a way to replace teeth that will be as cost-effective and minimally traumatic as possible. Nowadays, anterior fixed partial dentures can provide an esthetic result that is difficult to distinguish from the natural dentition. Consequently, any implant-supported prosthesis will be compared to the esthetic and functional standards set by conventional tooth-supported restorations. The restoration of the four maxillary incisors by means of an implant-supported prosthesis is one of the most challenging situations in implant dentistry. The questions of how many implants should be placed and where they should be positioned are especially important for achieving a superior end result. This article proposes and describes the placement of two platform-switched implants in the central incisor positions as a means of achieving the correct biomechanical behavior of the prosthesis, along with the best possible esthetic results.     

Anterior esthetic rehabilitation on teeth and dental implants optimized with Procera technology: a case report

With the latest developments of the Procera® system, all-ceramic crowns have become an attractive solution to provide functional and esthetic rehabilitation on teeth and dental implants. The Procera AllCeram crown and Procera Abutment embrace the concept of computer-assisted design and computer-assisted machining (CAD/CAM) and can be used together for optimal esthetic result. The purpose of this case report was to illustrate the advantages of these new components for complex anterior rehabilitation. Three natural teeth and a Procera Abutment were restored using four Procera AllCeram crowns. Treatment planning and esthetic benefits are discussed.
CLINICAL SIGNIFICANCE
For complex anterior rehabilitations, the Procera system fulfills both functional and esthetic objectives, providing a new way in the field of esthetic and restorative dentistry. Nevertheless, planning and preparation stages are decisive for successful treatment.     

Prosthodontic rehabilitation of dental implants with exposed threads: a clinical report

An unconventional technique was used to address the challenge of exposed dental implant threads. Titanium dental implants were prepared with rotary instruments to eliminate the exposed threads and to receive a fixed cementable prosthesis. The technique required fabrication of a gold casting of 2 copings connected by a round bar to fit the prepared implants and an implant-retained overdenture. This technique may be applied to other situations when multiple implants present with thread exposure and bone resorption. These include single crowns, partial fixed dental prostheses, and attachments for overdentures.     

Restorative material options for CAD/CAM restorations

Advances in adhesive dentistry and technological developments using dental computer-aided design (CAD)/computer-aided manufacturing (CAM) systems have provided alternative esthetic restorations to conventional laboratory processed restorations. Restorative materials for CAD/CAM-generated restorations must be able to withstand the rigors of the milling process, while providing clinical longevity once cemented. The esthetic restorative materials currently available for use with the Cerec System provide dentists with ceramic and polymer options for inlays, onlays, veneers, and crowns.     

短种植体和超短种植体在后牙区种植3年临床观察

目的：评价短种植体和超短种植体在后牙区种植的临床效果。方法：选择2009年10月至2010年6月在北京市中西医结合医院口腔科种植病例41例,共植入63颗Bicon种植体,其中34颗为短种植体,29颗为超短种植体,并进行单冠固定修复。通过临床观察、X线片检查评估种植体3年存留率。结果：在观察期内,63颗种植体中有3颗种植体脱落,其余60颗种植体均获得了良好骨结合,经3年临床观察及X线片检查,种植体颈部骨组织稳定,种植存留率达95．2％。其中短种植体存留率为94．1％,超短种植体存留率为96．6％。结论：在3年观察期内,短种植体和超短种植体应用于骨量不足后牙区种植临床效果良好,其存留率与传统种植体差异无统计学意义。     

Reconstruction of the edentulous maxillary arch by using prosthodontic implants

This article presented the treatment of the edentulous maxillary arch by using the Core-Vent implant system. The Core-Vent implant system can provide a suitable foundation for the support of a fixed or removable prosthesis. The results of the 17-year Branemark study as reported by Niznick indicates that "implants placed within the last 5 years of the study demonstrated a 95% success in the upper jaw and a 99% success in the lower jaw with success being defined as the maintenance of osseointegration." Niznick reported "that the clinical results achieved with the Swedish osseointegrated implants fulfill and exceed the criteria set by the 1978 Harvard Conference on dental implants (5 years success in 75%) but the implant procedure and prosthetic application lack the simplicity, versatility, and economy to serve as a viable alternative to conventional dentistry." As implant techniques become widely used, the cost of such procedures should become more affordable. Important modifications of implant systems should provide greater reliability and longevity of the restorations.     

Zirconia in fixed implant prosthodontics

Background: CAD/CAM technology in combination with zirconia ceramic has increasingly gained popularity in implant dentistry. Purpose: This narrative review presents the current knowledge on zirconia utilized as framework material for implant‐borne restorations and implant abutments, laboratory tests and developments, clinical performance, and possible future trends for implant dentistry are addressed. Material and Methods: A review of available literature from 1990 through 2010 was conducted with search terms zirconia,”“implants,”“abutment,”“crown,” and “fixed dental prosthesis” using electronic databases (PubMed) and manual searching. Results: Latest applications of zirconia in implant dentistry include implant abutments, multiple unit and full‐arch frameworks as well as custom‐made bars to support fixed and removable prostheses. High biocompatibility, low bacterial surface adhesion as well as favorable chemical properties of zirconia ceramics are reported. Zirconia stabilized with yttrium oxide exhibits high flexural strength and fracture toughness due to a transformation toughening mechanism. Preliminary clinical data confirmed the high stability of zirconia for abutments and as a framework material for implant borne crowns and fixed dental prostheses. Zirconia abutment or framework damage has rarely been encountered. However, veneering porcelain fractures are the most common technical complication in implant‐supported zirconia restorations. These porcelain veneer failures have led to concerns regarding differences in coefficient of thermal expansions between core and veneering porcelain and their respective processing techniques. Conclusion: As presently evidence of clinical long‐term data is missing, caution with regard to especially extensive implant‐borne zirconia frameworks is recommended.     

数字化口腔修复（4）-直接数字化制造

虽然口腔CAD／CAM方法依然是切削系统中的主流,但是加法制造技术也能更有效、更经济地为口腔医学提供可摘义齿支架和颅面重建的个性化固定装置。伴随更多的个性化材料的发展,修复体制造业将发生由传统的金属和陶瓷向着生物适合性的高强度聚合体、陶瓷和共熔合金方向转变。直接数字化制造将定义口腔医学的未来。数字化扫描、虚拟设计和数字化制造的进步将对传统的牙体预备,印模方法、义齿加工产生冲击。数字化的口腔技工室将经历由传统工匠向懂计算机的技师方向转变,并伴随着更先进的材料的应用,而获得高产量和高质量的回报。虽然,我们还不能够抛弃过去曾经应用于口腔医学中的常规原理,但是现在,口腔界的同仁们将为了患者去挑战和拥抱数字化口腔修复的新技术。     

A multidisciplinary treatment approach to a complicated maxillary dental trauma: a case report

This case report describes the treatment of an 18-year-old male who lost two central maxillary incisors due to dental trauma. Because of a deep overbite and serious occlusal instability, the lost teeth 11 and 21 could not be replaced by a conventional fixed prosthesis. The vertical dimension of occlusion was increased using a Hawley-type appliance over a period of 1 year. When sufficient intermaxillary space was gained the alveolar ridge was augmented with a mandibular symphysis graft. Nine months later two one-stage non-submerged implants (ITI, Straumann, Waldenburg, Switzerland) were inserted. After further soft tissue adaptation to two temporary acrylic crowns, porcelain veneers were placed on the two implants and the lateral incisors.     

Primary oral squamous cell carcinoma arising around dental osseointegrated implants mimicking peri-implantitis

Prosthodontic rehabilitation using dental implants has become a common practice in dentistry at the present time. The number of complications related to dental osseointegrated implants has increased according to the generalization of its use along the last decade. Among the most common of these complications are chronic inflammatory conditions affecting both hard and soft tissues around dental implants. Although severe complications are uncommon, in recent years several cases of oral squamous cell carcinoma adjacent to dental implants have been published. In this paper we present a new unusual case of primary oral squamous cell carcinoma arising around a dental fixed prosthesis over osseointegrated implants in a 76 male patient with no previous history of malignance and no risk factors related to oral cancer.     

Clinical performance of a newly developed spectrophotometric system on tooth color reproduction

STATEMENT OF PROBLEM: Matching a natural maxillary central incisor to a metal ceramic crown is one of the most difficult challenges in clinical dentistry due to the limitations of dental shade guides and the subjectivity of perceptual evaluation. PURPOSE: The purpose of this study was to assess the clinical effectiveness of a spectrophotometric shade-matching system on tooth color reproduction. MATERIAL AND METHODS: Two metal ceramic crowns were fabricated for a maxillary central incisor for 36 patients using 2 shade-matching techniques. The first technique was conventional visual matching using 3 shade guide systems, and the second was an instrument-based color-matching technique using a new spectrophotometric system. Color difference (DeltaE) values between the contralateral natural tooth and each of the 2 crowns were calculated in the cervical, middle, and incisal regions. The DeltaE values were compared using a Student's t test (alpha=.05). Three calibrated examiners evaluated the color match by ranking it from 1 to 10 (10 = perfect match; 1 = no match; < or =8, accepted; > or =7, rejected). McNemar's test was used to calculate the odds ratio of accepting restorations fabricated using a spectrophotometric system to conventional methods. RESULTS: Results revealed that the mean DeltaE values of crowns matched with the spectrophotometer were significantly lower than those using a conventional technique (P<.001). The odds ratio of 12.5 was calculated, indicating that conventionally matched crowns were more likely to be rejected than those matched using the spectrophotometer (P<.001). CONCLUSIONS: In this clinical study, crowns fabricated using a dedicated spectrophotometer had a significantly better color match and a lower rate of rejection due to shade mismatch compared to crowns fabricated with a conventional shade-matching method.     

Clinical performance of one‐piece zirconia dental implants: A systematic review

The aim of the present review was to evaluate the clinical and radiographic performance of one‐piece zirconia implants (O‐PZI). This review followed the PRISMA (Preferred Reporting Items for Systematic Review and Meta‐Analysis) guidelines that addressed the following focused question: What is the overall clinical and radiographic performance of O‐PZI? The MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Oral Health Group Trials Register databases were searched. Six clinical studies were included. For studies evaluating O‐PZI compared with one‐piece titanium implants, zirconia implants showed higher crestal bone loss (CBL) in both the studies. However, one study demonstrated a high failure rate compared to titanium dental implants, while one study demonstrated comparable survival rates between zirconia and titanium dental implants. For studies evaluating O‐PZI for the restoration of single crown and fixed dental prostheses, O‐PZI showed comparable bone loss and survival rates for single crowns and fixed dental prostheses. Two studies were included that compared O‐PZI with two‐piece zirconia (T‐PZI). One study showed a higher CBL and low survival rate for O‐PZI compared to T‐PZI, whereas the other study demonstrated comparable CBL and survival rates between O‐PZI and T‐PZI. It is still debatable whether O‐PZI demonstrate better clinical performance when compared with titanium implants or two‐piece design.     

Carbon-coated subperiosteal dental implants for fixed and movable prostheses.

Subperiosteal dental implants are not intended to replace conventional dentistry but provide an alternative method of treatment for the patient who cannot otherwise tolerate a dental prosthesis. Success can be achieved in the maxillae and in the mandible without the risk of serious complications. There are good prospects for a long-term favorable prognosis when appropriate surgical and prosthodontic criteria are observed.