The implant-supported milled-bar mandibular overdenture

Osseointegrated dental implants have been proven successful in the treatment of edentulism. The predictability of the implant‐supported prosthesis has also been established. Several techniques have been described for the successful restoration of the edentulous mandible: fixed‐detachable prostheses with either the original Brånemark hybrid prosthesis design or conventional implant‐supported fixed partial dentures, implant‐retained overdentures, and implant‐supported overdentures. However, in cases of advanced ridge resorption in which facial tissue support is needed from the flanges of the prosthesis or when a removable type of prosthesis is preferred by the patient, an implant‐supported prosthesis is indicated. Electric discharge machining is often used in the fabrication of the bar for an implant‐supported overdenture. This procedure is very costly and technique sensitive. An alternative procedure to fabricate a milled‐bar implant‐supported overdenture is described. This procedure is simple and uses inexpensive equipment and materials. The milled‐bar minimizes lateral and rotational displacement. The overdenture incorporates attachments that provide retention, minimizing possible movement along the path of insertion. This type of prosthesis is available to a broad patient population, especially those with advanced ridge resorption, providing an excellent result at a reduced cost.     

One clinical visit for a multiple implant restoration master cast fabrication

The making of a one-piece, long-span, implant-supported prosthesis with conventional procedures frequently has difficulties associated with the accuracy of fit. This article presents a clinical and laboratory procedure for making an accurate implant working cast that facilitates fabrication of the casting on the master cast. The procedure demonstrates the process of sectioning and rejoining of the resin between the transfer copings and then pouring the impression by first joining the analogs alone with impression plaster, sectioning it, and rejoining it again to stabilize the analogs, and finally, using dental stone to pour the impression. Clinical, radiographic, and laboratory (optical microscope) measurements for one clinical implant restoration confirm the accuracy of fit of this one prosthesis made with this procedure. Its advantage is that it can allow fabrication of the final casting on the cast, thereby eliminating the clinical time necessary to obtain repetitive solder indexes, and thus minimizing inconvenience to the patient. (J Prosthet Dent 1997;78:550-3.)     

Intrasurgical Implant Position Transfer and Interim Restoration Placement

In the esthetic zone, the placement of an interim prosthesis is an important stage in implant treatment for gingival contouring. This article presents a simple procedure for making an intraoperative implant position transfer to construct an interim prosthesis with optimal shape and emergence profile. This prosthesis, inserted at stage II surgery, guides soft tissue healing and aids in the fabrication of a definitive prosthesis with optimal gingival contours.     

Metal-ceramic screw-retained implant fixed partial denture with intraoral luted framework to improve passive fit

Passive fit of a long-span screw-retained implant prosthesis is an important criteria for the success of the restoration. This article describes a technique for fabricating a ceramometal implant fixed dental prosthesis (FDP) for a long-span partially edentulous situation by altering the conventional screw-retained design. The possibility of a passive fit is maximized by intraoral luting of the cast frame to milled abutments, and the potential framework distortion during fabrication is compensated to a major extent. Retrievability is ensured by screw retention of the prosthesis to the implants. Compared with conventional porcelain fused to metal screw-retained FDP, this prosthesis is relatively inexpensive to fabricate.     

Restoring the Edentulous Maxilla Using an Implant-Supported, Matrix-Assisted Secondary Casting

The selection of appropriate implant treatment modalities for the edentulous maxillary arch is complex. Although many patients are candidates for an implant-supported removable prosthesis, two major considerations affecting choice of treatment type are the amount of residual alveolar bone and soft tissue, and cost. A technique is described that employs a cast milled primary bar and a secondary casting constructed using a vacuum-formed 0.040-in plastic matrix. The secondary casting is intimately adapted to the primary bar and incorporates the retentive elements within it. The resulting prosthesis is less expensive than comparable designs, and retentive elements are easily replaceable. The technique is adaptable to most implant systems. The matrix-assisted secondary casting technique provides a design that is esthetic and hygienic. The prosthesis may also be easier to insert and remove than implant-supported removable prostheses that use plunger- or latch-type retention.     

The ray setting procedure: a new method for implant planning and immediate prosthesis delivery

This paper introduces a new system for planning implant positions directly on the working cast, called the ray setting procedure. It allows clinicians to obtain, on a master cast, the correct implant positions through the correction of previously planned expected positions. The device used is the Ray Set, a machine that can be used to precisely define, on the plaster working cast of the mouth, hard and soft tissue anatomy and correlate it with an articulator and computed tomographic data from the patient. This cast is used to build an individual surgical stent that perfectly matches the teeth and soft tissues as well as a provisional or definitive implant-supported prosthesis for partially or completely edentulous patients. A clinical case is presented to explain the procedure. A definitive all-ceramic cemented and screw-retained prosthesis, fabricated from a rigid material and with passive fit, was created before implant surgery and was placed with an immediate occlusal load applied a few minutes after implant placement. The prosthesis was retained with both cement and screws so as to make removal easy for accurate finishing of the margins immediately before cementation. The prosthesis was built, before implant surgery, according to the PIP method (presurgical implant prosthesis). The ray setting procedure can be used for planning immediate or delayed loading of implants.     

Implant-supported removable overdentures in the edentulous maxilla: clinical and technical aspects

PURPOSE: The aim of this article is to describe the indication criteria and the treatment planning for a maxillary implant-supported removable overdenture. Prostheses are designed according to the requirements of the bar system and the factors influencing the extension of the prosthesis base. MATERIALS AND METHODS: The decisive factors in determining whether a bar-retained overdenture prosthesis is indicated should be evaluated during the initial clinical examination and with the help of a reformatted computed tomographic (CT) scan that is performed with a radiologic template in place. Titanium markers represent the ideal location of the denture teeth in the diagnostic setup so that the implant position can be selected and the available space for the bar system can be assessed vertically and horizontally. RESULTS: For the overdenture prosthesis that is solely implant supported 6 to 8 implants are placed ideally at a distance of about 10 to 14 mm from center to center. A prefabricated bar system that allows the clips to be inserted between the implants can then be used. When the available bone restricts implant placement to adjacent tooth positions an individually milled bar that includes additional frictional pins and/or retentive elements needs to be planned. The prosthesis design, in particular its buccal and palatal flange extension, is determined during setup try-in, taking into account the patient's smile line, their need for facial support, and their phonetic requirements. CONCLUSION: The removable implant-supported overdenture offers flexibility in placing implants in either adjacent tooth positions or with greater distances between them depending on the available bone, as either conventional bar and clip systems or individually milled bars can be used. Adjustment of the buccal prosthesis flange and the palatal prosthesis base is made to fulfill the patient's requirements concerning esthetics, phonetics, comfort, and function.     

Surgical planning and prosthesis construction using computed tomography, CAD/CAM technology, and the Internet for immediate loading of dental implants

This report describes a protocol that uses computer technology and medical imaging to virtually place anterior and posterior dental implants and to construct a precise surgical template and prosthesis, which is connected at the time of implant placement. This procedure drastically reduces patient office time, surgical treatment time, and the degree of post-treatment recovery. Patients with an edentulous arch or a partially edentulous area had a denture with radiopaque markers constructed for computed tomography (CT) scans of the appropriate jaw. The CT images, having acquisition slices of 0.4 mm, are transposed in a three-dimensional image-based program for planning and strategic placement of dental implants. After virtual implant placement on the computer, the surgical treatment plan is sent to a manufacturing facility for construction of the surgical template. The manufactured surgical components and surgical template arrive on the clinical site. From the surgical template, the dental laboratory retro-engineers the master cast, articulates it with the opposing dentition based on a duplicate of the scanning denture, and creates the prosthesis. Using the surgical template, minimally invasive surgery is performed without a flap, and the prosthesis is delivered, achieving immediate functional loading to the implants. Minor occlusal adjustments are made. The total surgical treatment time required is typically between 30 and 60 minutes. Postoperative symptoms such as pain, swelling, and inflammation are dramatically reduced. CLINICAL SIGNIFICANCE: Identification of the bone in relationship to the tooth position via three-dimensional CT prior to surgery allows the clinician to precisely place implants. Computer-aided design/computer-assisted manufacture technology using the three-dimensional images allows for fabrication of the surgical template. This is a significant advancement in implant dentistry and promotes interdisciplinary approaches to patient treatment. The implant surgeon and restorative dentist can agree upon implant locations and screw access locations prior to the surgical episode.     

A technique for immediately restoring single dental implants with a CAD-CAM implant-supported crown milled from a poly(methyl methacrylate) block

This technique is used when a single dental implant is placed. A stent made of autopolymerized acrylic resin was used to transfer the implant position to the laboratory. Once the implant position was transferred, the stone cast was scanned, and a computer-aided design and computer-aided manufacturing (CAD-CAM) interim implant-supported crown was milled from a poly(methyl methacrylate) (PMMA) block. A titanium insert, in contact with the implant platform and not the PMMA material, was used to support the crown. The interim prosthesis was then placed intraorally. The soft tissues were sutured, and the interim prosthesis was left for a period of at least 3 months to confirm osseointegration and allow the soft tissue to heal. A CAD-CAM titanium impression coping was made and used for the definitive impression. The contours of the impression coping were identical to the contours of the interim restoration. The data of the digital design of the interim prosthesis were saved, and the definitive prosthesis was fabricated with contours identical to those of the interim prosthesis.     

Oral rehabilitation of a patient with bruxism and cluster implant failures in the edentulous maxilla: a clinical report

For most patients with failed dental implants, the placement of new implants is the only option that allows for retreatment with a fixed dental prosthesis. This clinical report describes the rehabilitation of a patient with a history of bruxism and cluster implant failures in the edentulous maxilla 10 years after the insertion of a milled bar overdenture. Seven failed implants were removed and simultaneous bone grafting was performed. After an 8-month healing period, 8 dental implants with new surfaces were placed. These supported a metal ceramic fixed complete denture with a metal occlusal surface. The prosthesis was retained with 3 sections of milled bars and 3 set screws. This clinical report describes the details of the treatment with an emphasis on prosthetics.     

Use of Diagnostic and Surgical Stent: A Simplified Approach for Implant Placement

Dental implantology has emerged as a practical alternative to traditional prosthodontics. Since the beginning, placement of implant in the bone to achieve a prosthetic solution that fulfils biologic, aesthetic and biomechanical requirements has been a challenge. In the past, implant site and inclination were dictated by residual bone quality. The desire for predictable prosthesis led to the development of prosthetically guided implantology. This concept establishes the correct implant position during the diagnostic stage according to planned definitive restoration. In prosthetically guided implantology where ideal placement of implant is determined by the definitive restoration, use of radiographic and surgical stent in conjunction with dental CT scan can play an important role. A stent is an appliance used for radiographic evaluation during treatment planning for implant placement and during surgical procedures to locate optimal implant placement site. The stent with dental CT scan enables the dental team to identify specific sites of prospective implant surgery and hence determines the optimal position and angulation of implant relative to occlusal load. Aided by stent the surgeon can avoid undesirable implant site preparation and minimize unnecessary osteotomy, resulting in favorable design of prosthesis, reduced surgical trauma, reduced surgical time and increased patient comfort. This case report is an insight into the method of fabrication of simple and cost effective stent for implant placement and its advantages over the other techniques of stent fabrication.     

The milled bar-retained removable bridge implant-supported prosthesis: a treatment alternative for the edentulous maxilla

Restoration of the edentulous jaw with dental implants can be achieved using either an implant-supported prosthesis, such as a fixed bridge, or an implant-retained prosthesis, such as a traditional overdenture. The implant-retained prostheses use edentulous ridges as primary stress-bearing regions, and through stress-breaking mechanisms, the implants are not loaded during function. However, the success rates of maxillary overdentures do not appear to be as good as for mandibular overdentures; this may be attributable to the adverse loading conditions, short implant length, poor quality of bone, number of implants used, flexible bar design, or poor treatment planning. Many articles have also described the numerous problems and multiple visits required in maintaining a traditional bar-retained overdenture restoration, often making it more expensive in the long term than a fixed restoration. The milled bar implant-supported prosthesis offers the benefits of both fixed and removable restorations. Its infrastructure provides the same rigidity as the fixed restoration, owing to the precise fit to the superstructure, which is removable, to promote adequate access for hygiene, yet it still provides lip support and maintains close contact with the soft tissues. These advantages enhance phonetics, esthetics, correct lip support, maintenance, and patient comfort.
CLINICAL SIGNIFICANCE
Restoring esthetics and function for the edentulous patient requires a multidiscipline approach for success. This article discusses the techniques for restoring function and esthetics for these patients, using a milled bar restoration supported and retained by dental implants.     

The Dentoalveolar Prosthesis: A Novel Approach in the Reconstruction of Hard and Soft Tissue Deficiencies

A clinical problem commonly encountered by the advanced restorative dentist is a requirement to replace missing teeth and the supporting alveolus in areas adjacent to healthy or manageable dentition. A potential solution could utilize a dentoalveolar prosthesis fabricated on two or more implants in the edentulous area. The implant substructure, or framework, may be cast, milled, or selectively laser melted from a variety of metals. A superstructure, or ceramic overlay incorporating a ceramic or composite resin gingival tissue component, is constructed to fit over the implant substructure and luted to the substructure with resin cement. This implant‐supported fixed dental prosthesis identifies a solution for the replacement of both teeth and supporting alveolar bone. It restores comfort, function, and esthetics to the patient.     

Prosthetically driven, computer-guided implant planning for the edentulous maxilla: a model study

Objectives: To analyze computer‐assisted diagnostics and virtual implant planning and to evaluate the indication for template‐guided flapless surgery and immediate loading in the rehabilitation of the edentulous maxilla. Materials and Methods: Forty patients with an edentulous maxilla were selected for this study. The three‐dimensional analysis and virtual implant planning was performed with the NobelGuide? software program (Nobel Biocare, Göteborg, Sweden). Prior to the computer tomography aesthetics and functional aspects were checked clinically. Either a well‐fitting denture or an optimized prosthetic setup was used and then converted to a radiographic template. This allowed for a computer‐guided analysis of the jaw together with the prosthesis. Accordingly, the best implant position was determined in relation to the bone structure and prospective tooth position. For all jaws, the hypothetical indication for (1) four implants with a bar overdenture and (2) six implants with a simple fixed prosthesis were planned. The planning of the optimized implant position was then analyzed as follows: the number of implants was calculated that could be placed in sufficient quantity of bone. Additional surgical procedures (guided bone regeneration, sinus floor elevation) that would be necessary due the reduced bone quality and quantity were identified. The indication of template‐guided, flapless surgery or an immediate loaded protocol was evaluated. Results: Model (a) – bar overdentures: for 28 patients (70%), all four implants could be placed in sufficient bone (total 112 implants). Thus, a full, flapless procedure could be suggested. For six patients (15%), sufficient bone was not available for any of their planned implants. The remaining six patients had exhibited a combination of sufficient or insufficient bone. Model (b) – simple fixed prosthesis: for 12 patients (30%), all six implants could be placed in sufficient bone (total 72 implants). Thus, a full, flapless procedure could be suggested. For seven patients (17%), sufficient bone was not available for any of their planned implants. The remaining 21 patients had exhibited a combination of sufficient or insufficient bone. Discussion: In the maxilla, advanced atrophy is often observed, and implant placement becomes difficult or impossible. Thus, flapless surgery or an immediate loading protocol can be performed just in a selected number of patients. Nevertheless, the use of a computer program for prosthetically driven implant planning is highly efficient and safe. The three‐dimensional view of the maxilla allows the determination of the best implant position, the optimization of the implant axis, and the definition of the best surgical and prosthetic solution for the patient. Thus, a protocol that combines a computer‐guided technique with conventional surgical procedures becomes a promising option, which needs to be further evaluated and improved.     

An Alternative Approach in Fabrication of Fixed Complete Dentures Using a Duplicate Denture

The traditional prosthetic steps in the fabrication of a fixed complete denture after implant osseointegration include final impression, verification of implant positioning in the working cast, mounting of the working cast, and mock denture wax trial insertion prior to the laboratory fabrication of the metal substructure; however, in patient scenarios of immediate loading of implants, the interim conversion prosthesis can be used to advance from the final impression to the milling of the underlying framework in one appointment. Consistency in the initial wax trial insertion, radiographic guide, and intraoral positioning of the conversion prosthesis can result in a well‐designed definitive prosthesis in less time with the use of the existing duplicate complete denture.     

Use of Implant‐Supported Custom Milled Impression Copings to Capture Soft‐Tissue Contours and Incisal Guidance

A technique is presented where a custom milled impression coping is used to replicate the clinically established anterior incisal guidance to the definitive prosthesis when multiple implants are restored in the esthetic zone. A conventional impression is initially made, then the stone cast is scanned, and a digitally designed custom screw‐retained, implant‐supported interim prosthesis is milled from a polymethylmethacrylate (PMMA) billet. This is aimed to digitally design the pontic areas, contour the gingival soft tissue, and establish an anterior incisal guidance. A custom milled impression coping (CMIC) is then fabricated. The CMIC has contours similar to the contours of the interim prosthesis and is fabricated from a PMMA billet. Titanium inserts are placed in the interim prosthesis and the CMIC. The CMIC is inserted intraorally and used for the final impression by using a custom tray and by following the open tray impression protocol. With the proposed technique, the exact contours of the digitally designed and clinically verified interim prosthesis are used to fabricate the definitive restoration.     

金沉积技术在无牙颌种植覆盖义齿修复中的临床应用

目的:探讨金沉积技术在无牙颌种植修复中的临床应用效果。方法:49例无牙颌患者,完成无牙颌覆盖义齿63个,植入种植体361个。应用金沉积技术制作双重冠和切削杆外冠。观察方法为临床检查及x线检查。修复后追踪最长44个月,最短12个月。结果:所有病例在修复后至最后一次复查未见种植体脱落。所有修复体无折断、松动或破损,修复效果良好,患者满意。结论:本研究结果提示金沉积技术用于制作种植体支持的无牙颌修复体具有良好的生物相容性,可用于种植体支持的覆盖义齿修复,近期临床效果满意。     

Clinical experience of CNC-milled titanium frameworks supported by implants in the edentulous jaw: a 3-year interim report

Background: The use of computer numeric controlled (CNC)‐milled titanium frameworks is a new technique for framework fabrication, and few clinical reports have been made on this treatment modality. Purpose: The goal of this study was to report the clinical performance of implant‐supported prostheses with CNC‐milled titanium frameworks in the edentulous jaw and to compare the results with prostheses provided with conventional cast frameworks during the first 3 years of function. Materials and Methods: A consecutive group of 126 edentulous patients were provided by random distribution with 67 prostheses with CNC‐milled titanium frameworks in 23 upper and 44 lower jaws and 62 conventional prostheses with gold‐alloy castings in 31 upper and 31 lower jaws. Radiographic 1‐year data and clinical 3‐year data were collected for both the titanium and control group. Results: One prosthesis was lost in each group owing to loss of implants, and the overall 3‐year prosthesis cumulative survival rate was 98.2% for both groups. Patients with smoking habits experienced significantly more implant failures than nonsmokers (p =.006). Few problems were observed. No metal fractures were seen in the test group, whereas two frameworks and one abutment screw fractured in the control group. Resin veneer fractures were the most common complication, with a slightly higher incidence observed in the control group. Conclusions: Computer numeric controlled‐milled titanium frameworks can be used as an alternative to conventional castings in the edentulous jaw, presenting clinical performance similar to that of conventional cast frameworks during the first 3 years of function.     

Spark erosion fixed/detachable prosthesis for the completely edentulous maxilla.

A technique is described for restoration of the completely edentulous maxilla. From six to eight root-form implants are surgically placed in the edentulous maxilla. A hybrid overdenture is constructed by use of a two-degree tapered precision milled primary bar. A cast overdenture prosthesis is constructed over this bar, and precision attachments are spark-erosion-processed to the primary and secondary prosthetic components. The technology described in this article allows for an intimate fit of the various prosthetic components. This prosthetic protocol permits maximum retention and stability of the prosthesis and solves many problems which are encountered in the oral rehabilitation of the edentulous maxilla.     

Implant-retained overdenture design for the malpositioned mandibular implants

In the rehabilitation of the edentulous mandible, implant-retained overdenture represents a viable and cost-effective treatment. Successful prosthetic integration of this treatment relies on the accurate 3-dimensional position and angulation of the implant fixtures. If these requirements are not fulfilled, implant malposition occurs and negative effects on the function, esthetics, and structural integrity of the prosthesis may follow. Implant malposition commonly results from poor planning, surgical error, inaccuracies in the radiographic/surgical template fabrication, and the instability of the template during surgery. Potential solutions for implant malposition include surgical re-treatment or prosthetic compensation in the form of an altered design of the final prosthesis. This article presents a prosthetic design of an overdenture for malpositioned implants in the anteroposterior plane. Prosthetic compensations included relocating the attachment mechanism into the bulk of the overdenture with the help of an interconnecting implant bar and a metal reinforcing framework for the overdenture.