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Purpose: The aim of this study was to evaluate the effect of a computer-aided design/computer-assisted manufacturing (CAD/CAM) guide on drilling the screw-access channel for lingually placed implants., Materials and Methods: Screw-channel drilling guides were fabricated on lingually placed implant models using CAD/CAM technology. The screw channels were prepared with guided or freehand drilling by 20 dental graduates. The accuracy of each screw channel was assessed for drilling entry point, channel volume, and angulation (α = .05)., Results: The guided drilling group showed smaller deviations than the freehand drilling group, and prosthesis position influenced the guide effect (P < .001)., Conclusion: The CAD/CAM guide facilitated the screw channel preparation of cement-retained prostheses supported by lingually placed implants.

Objective: To compare the precision of fit of full-arch implant-supported screw-retained computer-aided designed and computer-aided manufactured (CAD/CAM) titanium-fixed dental prostheses (FDP) before and after veneering. The null-hypothesis was that there is no difference in vertical microgap values between pure titanium frameworks and FDPs after porcelain firing., Materials and Methods: Five CAD/CAM titanium grade IV frameworks for a screw-retained 10-unit implant-supported reconstruction on six implants (FDI tooth positions 15, 13, 11, 21, 23, 25) were fabricated after digitizing the implant platforms and the cuspid-supporting framework resin pattern with a laser scanner (CARES(®) Scan CS2; Institut Straumann AG, Basel, Switzerland). A bonder, an opaquer, three layers of porcelain, and one layer of glaze were applied (Vita Titankeramik) and fired according to the manufacturer's preheating and fire cycle instructions at 400-800 °C. The one-screw test (implant 25 screw-retained) was applied before and after veneering of the FDPs to assess the vertical microgap between implant and framework platform with a scanning electron microscope. The mean microgap was calculated from interproximal and buccal values. Statistical comparison was performed with non-parametric tests., Results: All vertical microgaps were clinically acceptable with values <90 μm. No statistically significant pairwise difference (P = 0.98) was observed between the relative effects of vertical microgap of unveneered (median 19 μm; 95% CI 13-35 μm) and veneered FDPs (20 μm; 13-31 μm), providing support for the null-hypothesis. Analysis within the groups showed significantly different values between the five implants of the FDPs before (P = 0.044) and after veneering (P = 0.020), while a monotonous trend of increasing values from implant 23 (closest position to screw-retained implant 25) to 15 (most distant implant) could not be observed (P = 0.169, P = 0.270)., Conclusions: Full-arch CAD/CAM titanium screw-retained frameworks have a high accuracy. Porcelain firing procedure had no impact on the precision of fit of the final FDPs. All implant microgap measurements of each FDP showed clinically acceptable vertical misfit values before and after veneering. Thus, the results do not only show accurate performance of the milling and firing but show also a reproducible scanning and designing process., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The purpose of this in-vitro study was to evaluate the influence of the framework design on the durability of inlay-retained cantilever fixed dental prostheses (IR-FDPs), made from zirconia ceramic, after artificial ageing. Forty-eight caries-free human premolars were prepared as abutments for all-ceramic cantilevered IR-FDPs using six framework designs: occlusal-distal (OD) inlay, OD inlay with an oral retainer wing, OD inlay with two retainer wings, mesial-occlusal-distal (MOD) inlay, MOD inlay with an oral retainer ring, and veneer partial coping with a distal box (VB). Zirconia IR-FDPs were fabricated via computer-aided design/computer-aided manufacturing (CAD/CAM) technology. The bonding surfaces were air-abraded (50 μm alumina/0.1 MPa), and the frameworks were bonded with adhesive resin cement. Specimens were stored for 150 d in a 37°C water bath during which they were thermocycled between 5 and 55°C for 37,500 cycles; thereafter, they were exposed to 600,000 cycles of dynamic loading with a 5-kg load in a chewing simulator. All surviving specimens were loaded onto the pontic and tested until failure using a universal testing machine. The mean failure load of the groups ranged from 260.8 to 746.7 N. Statistical analysis showed that both MOD groups exhibited significantly higher failure loads compared with the other groups (i.e. the three OD groups and the VB group) and that there was no significant difference in the failure load among the OD groups and the VB group. In conclusion, zirconia IR-FDPs with a modified design exhibited promising failure modes., (© 2014 Eur J Oral Sci.)

The treatments with composite prosthesis require the completion of milling. These precision preparations in the fixed prosthesis promote the integration of removable partial denture with metallic framework in mechanical (prosthetic balance), physiological, aesthetical and psychological point of view. Their conception and realization are always subordinated to the balance principles of the removable partial denture. The precision they require need the use of a dental milling machine working along the predetermined insertion axis of the partial denture casting and require an excellent communication and a close collaboration between dentist and experienced technician of laboratory. In this paper, after a recalling about the milling (definition, description, interests), we will detail the steps to achieve clinical and laboratory needs for a rehabilitation by composite prosthesis combining milling, and it will be illustrated through a clinical case with a bilateral tooth-supported edentulous in the maxilla.

Purpose: To evaluate the load-bearing capacities of fiber-reinforced composite (FRC) fixed dental prostheses (FDP) with pontics of various materials and thicknesses., Materials and Methods: Inlay preparations for retaining FDPs were made in a polymer phantom model. Seventy-two FDPs with frameworks made of continuous unidirectional glass fibers (everStick C&B) were fabricated. Three different pontic materials were used: glass ceramics, polymer denture teeth, and composite resin. The FDPs were divided into 3 categories based on the occlusal thicknesses of the pontics (2.5 mm, 3.2 mm, and 4.0 mm). The framework's vertical positioning varied respectively. Each pontic material category contained 3 groups (n = 8/group). In group 1, pontics were fabricated conventionally with composite resin (G-ӕnial, GC) with one additional transversal fiber reinforcement. In group 2, the pontics were polymer denture teeth (Heraeus- Kulzer). Group 3 had an IPS-Empress CAD pontic (Ivoclar Vivadent) milled using a Cerec CAD/CAM unit. Groups 1 and 2 served as controls. Each FDP was statically loaded from the pontic until initial fracture (IF) and final fracture (FF). Initial-fracture data were collected from the load-deflection graph., Results: ANOVA indicated statistically significant differences between the materials and occlusal thicknesses (p < 0.001). Quadratic analysis demonstrated the highest correlation between the thickness of the pontic and IF and FF values with ceramic pontics (IF: p < 0.001; R2 = 0.880; FF: p < 0.001; R2 = 0.953)., Conclusion: By increasing the occlusal thickness of the pontic, the load-bearing capacity of the FRC FDPs may be increased. The highest load-bearing capacity was obtained with 4.0 mm thickness in the ceramic pontic. However, with thinner pontics, polymer denture teeth and composite pontics resulted in higher load-bearing values.

Unlabelled: The clinical and laboratory steps involved in rehabilitating the maxillary arch following the loss of several teeth due to periodontal disease are outlined in this case report. This article illustrates the use of a laboratory based CAD/CAM system (Sirona In-Lab) and a copy milling technique in the fabrication of a fixed-movable bridge, high strength, all-ceramic, cross-arch bridge., Clinical Relevance: Adopting a semi-fixed approach in cross-arch rehabilitation has conventionally involved the use of porcelain fused to metal (PFM) components but the demands placed by patients and clinicians have led to the development of novel techniques in order to achieve highly aesthetic and functional results.

Despite requiring dental crown preparation and possible root canal treatment, besides the difficulty of clinical and laboratory repairs, and financial burden, the association between fixed (FPD) and removable partial dentures (RPD) by means of attachments is an important alternative for oral rehabilitation, particularly when the use of dental implants and FPDs is limited or not indicated. Among the advantages of attachment-retained RPDs are the improvements in esthetics and biomechanics, as well as correction of the buccal arrangement of anterior teeth in Kennedy Class III partially edentulous arches. This article describes the treatment sequence and technique for the use of attachments in therapy combining FPD/RPD., (© 2013 by the American College of Prosthodontists.)

Many treatment options are currently available for single tooth replacement, such as metal-ceramic, all-ceramic, direct or indirect fiber-reinforced composite fixed dental prostheses (FDPs) or implants. Inlay-retained FDPs could be indicated especially when adjacent teeth have preexisting restorations and where implant placement is not possible or not indicated. In such cases, indication of both metal-ceramic and fiber-reinforced composite FDPs has certain disadvantages. This paper describes the use of all-ceramic inlay-retained FDPs with zirconia frameworks, veneered with a press-on technique. The retainer margins were made of pressed ceramic to make adhesive luting possible. In deep cavities, a full contour press-on ceramic all around the retainers increased the available surface area for the adhesive approach.

When creating optimally esthetic contemporary prosthetic restorations, clinicians should balance patient preferences and requests with functional and esthetic demands. Beyond fulfilling the treatment objectives of restoring function and optimizing esthetics, the combination of fixed and removable dental prostheses should also blend seamlessly into the oral environment. Treatment planning and proper design of the prostheses is of paramount importance, while knowledge of material science and laboratory steps is needed to guarantee successful execution of clinical procedures. This article provides methods and techniques for improvement of the esthetic outcome through the description of clinical and laboratory steps of a clinical case.

Objectives: Inlay-retained fixed partial dentures are conservative prosthetic restorations. Their failure resistance is influenced by the stress distribution that depends on the material properties as well as the loading conditions. Finite element analysis provides the ability to estimate the loading capacity by simulating the stress distribution in all-ceramic dental restorations. The null-hypothesis of this study was that tooth mobility or tooth bearing condition significantly influences the stress distribution and therefore the failure resistance of all-ceramic inlay-retained fixed dental prostheses. Therefore, the stress distribution under different loading and bearing conditions of the teeth was analyzed using the finite element method., Methods: Three different bearing conditions, one fixed and two flexible were chosen to simulate tooth mobility. The flexible models were constrained with spring elements to a virtual center of rotation. In addition, loading conditions were varied., Results: The influence of tooth mobility on the stress distribution depended on the degree of modeled tooth mobility, as well as the loading conditions. The maximum first principal stresses differed significantly in magnitude and location depending on the modeled bearing condition and the simulated load case. The maximum difference between fixed and flexible model was more than 100%., Significance: Tooth mobility and occlusal loading conditions have to be considered in finite element analyses as the simulated stress distribution is strongly influenced by these factors., (Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.)

Precision attachments have been used for many years to retain removable partial dentures (RPDs). Common reasons for a failed attachment-retained RPD are fracture of the framework, fracture of the roots or teeth, and irretrievable decrease of retention. When an RPD framework major connector has been fractured, it should be remade. This article describes a technique to remake a fractured mandibular RPD using cast round profile attachment analogs without the need for replacement of the fixed partial denture., (© 2012 by the American College of Prosthodontists.)

Objective: To improve its mechanical performance, structural optimization had been used in a previous study to obtain an alternative design for a 3-unit inlay-retained fiber-reinforced composite (FRC) dental bridge. In that study, an optimized layout of the FRC substructure had been proposed to minimize stresses in the veneering composite and interfacial stresses between the composite and substructure. The current work aimed to validate in vitro the improved fracture resistance of the optimized design., Methods: All samples for the 3-unit inlay-retained FRC dental bridge were made with glass-fibers (FibreKor) as the substructure, surrounded by a veneering composite (GC Gradia). Two different FRC substructure designs were prepared: a conventional (n=20) and an optimized design (n=21). The conventional design was a straight beam linking one proximal box to the other, while the optimized design was a curved beam following the lower outline of the pontic. All samples were loaded to 400N on a universal test machine (MTS 810) with a loading speed of 0.2mm/min. During loading, the force and displacement were recorded. Meanwhile, a two-channel acoustic emission (AE) system was used to monitor the development of cracks during loading., Results: The load-displacement curves of the two groups displayed significant differences. For the conventional design, there were numerous drops in load corresponding to local damage of the sample. For the optimized design, the load curves were much smoother. Cracks were clearly visible on the surface of the conventional group only, and the directions of those cracks were perpendicular to those of the most tensile stresses. Results from the more sensitive AE measurement also showed that the optimized design had, on average, fewer cracking events: 38 versus 2969 in the conventional design., Significance: The much lower number of AE events and smoother load-displacement curves indicated that the optimized FRC bridge design had a higher fracture resistance. It is expected that the optimized design will significantly improve the clinical performance of FRC bridges., (Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.)

The clinical use of all-ceramic crowns and fixed partial dentures has seen widespread adoption over the past few years due to their increasing durability and longevity. However, the application of inlays as an abutment design has not been as readily embraced because of their relatively high failure rates. With the use of an idealized inlay preparation design and prosthesis form which better distributes the tensile stresses, it is possible to utilize the inlay as support for an all-ceramic fixed partial denture. Utilizing a three-dimensional finite element analysis, a direct comparison of the inlay supported all-ceramic bridge against the traditional full crown supported all-ceramic bridge is made. The results demonstrate that peak stresses in the inlay bridge are around 20% higher than in the full crown supported bridge with von Mises peaking at about 730 MPa when subjected to theoretical average maximum bite force in the molar region of 700 N, which is similar to the ultimate tensile strengths of current zirconia based ceramics., (© 2011 Australian Dental Association.)

Passively retained precision attachment partial dentures have been used successfully on natural tooth abutments since the 1920s. However, the dental profession has not advocated their use with implant abutments. When used in the passive manner that has proven successful on natural tooth abutments, precision attachment cases on implant abutments can be an excellent treatment option. This type of case has been used successfully for more than 17 years and offers tremendous advantages over the conventional overdenture approach to removal restorations on implant abutments.

Currently, there are many options for single-tooth replacement: metal-ceramic, all-ceramic, direct or indirect fibre-reinforced composite fixed dental prostheses (FDPs) or implants. Inlay-retained FDPs may especially be indicated when adjacent teeth have been previously restored and when implant placement is not possible or not indicated. In such cases, both metal-ceramic and fibre-reinforced composite FDPs have certain disadvantages. In this paper, we describe the use of all-ceramic inlay-retained FDPs with zirconia frameworks, veneered using a press-on technique.

A 41-year-old man with cleft palate presented with a wide dehiscence and missing teeth. Six implants had been placed for fabrication of an overdenture, which was unsatisfactory. A bar was waxed and cast for connection to the implants; precision attachments were placed laterally for retention. A fixed partial denture was fabricated, and milled crowns were fabricated at the molar region to provide a guiding plane for insertion of a removable palatal obturator. Good swallowing and speech outcomes were achieved. This technique provided functional and esthetic benefits, enhanced oral hygiene, and improved the psychological condition of the patient.

Background and Objective: Intrusion of natural teeth is a very common and interesting problem associated with implant-assisted fixed partial prostheses. Various theories have been put forth to explain this phenomenon, most of which revolve around the philosophy of exertion of excessive forces onto the natural tooth in a combination fixed partial denture. This photoelastic study examines the current theories revolving around intrusion and evaluates whether natural tooth intrusion is a definite possibility in an implant-tooth-connected fixed partial prosthesis., Materials and Methods: A two-dimensional photoelastic method was employed for testing and analysis. Two sets of photoelastic models were fabricated, one depicting a totally tooth-supported situation and the other an implant-tooth-supported situation. A rigid type and non-rigid type of connection were also incorporated into the fixed partial denture used in the both the situations in the study. Loads were applied on the anterior and posterior abutments and the pontic regions in both sets of models and the fringe patterns were photographically recorded for analysis., Results and Conclusion: The forces were proportionately consistent with the increase in applied loads in both the situations. The use of a non-rigid connection did not show any major significance but in fact may be erroneous. The forces were considerably higher in the implant-tooth-connected situation. The results indicated that the differences in the forces exerted were not light and continuous and may not cause tooth intrusion. Natural tooth intrusion may be caused by reasons other than excessive forces and needs further investigation.

This is a case report of the restoration of a partially edentulous atrophic anterior maxilla and atrophic mandibular posterior ridges. This case report demonstrates one method for successful treatment of partial edentulism at No. 7 to 10, where interlock attachments on natural cuspids and mini dental implants support an acrylic-based screwless fixed detachable partial denture to provide lip support and masticatory function in the anterior maxilla. The presenting qualities of this case were similar to combination syndrome.

Cherubism is an early childhood disease that primarily involves the mandible and consists of painless mandibular enlargement with or without maxillary involvement and progresses rapidly over the course of several years. This clinical report describes the fabrication of maxillary fixed partial dentures and a mandibular overdenture for a 21-year-old man with cherubism.

It is now possible to provide combination fixed/removable prosthetic restorations using only 1 dental alloy, such as CoCr, a nonprecious alloy. This alloy offers clinical performance and demonstrated corrosion resistance. This clinical report demonstrates use of a single CoCr alloy for metal-ceramic fixed partial dentures in conjunction with a mandibular removable partial denture.

Statement of Problem: The clinical outcome of complete-arch fixed prostheses supported by implants and natural tooth abutments in patients with normal or reduced periodontal support has been reported by few studies, with controversial results., Purpose: The purpose of this study was to report on the implant success rate, prosthetic complications, and the occurrence of tooth intrusion, when complete-arch fixed prostheses, supported by a combination of implants and teeth, were fabricated for patients with normal and reduced periodontal support., Material and Methods: Nineteen patients with residual teeth that served as abutments were consecutively treated with combined tooth- and implant-supported complete-arch fixed prostheses and were retrospectively evaluated after a period varying from 24 to 94 months. Nine patients showed reduced periodontal support as a result of periodontal disease and treatment (RPS group), and 10 patients had normal periodontal support of the abutment teeth (more than 2/3 of periodontal support [NPS group]). Ninety implants and 72 tooth abutments were used to support 19 fixed partial dentures. Screw- and cement-retained metal-ceramic and metal-resin prostheses were fabricated with rigid and nonrigid connectors. Implant survival and success rates, occurrence of caries and tooth intrusion, and prosthetic complications were recorded. The number of teeth, implants, prosthetic units, fixed partial dentures, and nonrigid connectors were compared with a t test to assess differences between the 2 groups, while data for the occurrence of intrusions and prosthetic complications were compared with the Fisher exact test (alpha=.05)., Results: One of the 90 implants was lost (99% survival rate) over 24 to 94 months, while 3 implants showed more than 2 mm of crestal bone loss (96% success rate) over the same period. No caries were detected, but 5.6% (4/72) of the abutment teeth exhibited intrusion. Intrusion of abutment teeth was noted in 3 patients who had normal periodontal support (13% of teeth in NPS group) of the abutment teeth and was associated with nonrigid connectors. No intrusion of teeth was noted in the patients exhibiting reduced periodontal support regardless of the type of connector or when a rigid connector was used for either group. The number of intruded teeth was significantly greater in patients with intact periodontal support (P=.03)., Conclusions: Complete-arch fixed prosthesis supported by implant and tooth abutments may be associated with intrusion of teeth with intact periodontal support when nonrigid connectors are used to join the implant- and tooth-supported sections of the prostheses. However, fixed partial dentures supported by implants and teeth with reduced periodontal support were not associated with tooth intrusion, regardless of the type of connectors used.

Purpose: In a retrospective study, the radiographs of 39 patients with Applegate-Kennedy Class I or II in the posterior mandible who had been treated with screw-anchored fixed partial dentures supported by IMZ implants and natural teeth were examined for the presence of radiologically detectable peri-implant bone loss. Furthermore, the results were correlated with a mathematical model., Materials and Methods: The radiographs of the implants were digitized, and the areas of bone atrophy mesial and distal to the implants were determined semi-automatically. The data obtained were correlated with the distance between the implant and the abutment tooth. The connection between the tooth-supported crown and the implant-supported denture was made with a vertical screw-lock precision attachment. In a mathematical analysis it was assumed that the fixed partial prosthesis was a rigid beam with 3 elastically embedded supports., Results: The mean distance between the tooth and the first implant was 11.02 mm (SD: 4.24), and between the tooth and the second implant was 20.25 mm (SD: 5.16). Peri-implant bone loss significantly followed a rational function (mesial implant: P = .03, distal implant: P = .02), meaning that, as the tooth-implant distance increased, the area of atrophy became rapidly larger and then diminished gradually. Distances of 8 to 14 mm between the tooth and the first implant and of 17 to 21 mm between the tooth and the second implant were associated with a more pronounced bone loss. These results were also confirmed mathematically., Conclusion: A tooth-implant distance of 8 to 14 mm for the first implant and 17 to 21 mm for the second implant should be avoided for implant placement if prosthetic rehabilitation is planned using a fixed partial denture supported by a premolar and 2 IMZ implants in the mandible. Although this investigation was done on IMZ implants only, the results were confirmed by a mathematical model, which indicated that the observed bone loss may be the same in other types of implants placed in the same positions.

Statement of Problem: Fiber-reinforced composite inlay fixed partial dentures (FRCIFPDs) may be a reliable prosthetic solution. Clinical procedures involved in their fabrication have been defined, but little is known about their mechanical behavior., Purpose: This in vitro study used the finite element (FE) method to investigate 3-dimensional (3-D) stress and strain distribution produced in a 3-unit FRCIFPD., Material and Methods: A 3-D FE model (227,768 3-D tetrahedral elements) of a 3-unit FRCIFPD cemented onto box-shaped prepared teeth was developed. Stress and strain distribution generated by a maximum load of 196 N applied vertically or laterally to the FRCIFPD centrally, on an area of 4 +/- 0.1 mm 2 , was analyzed. The specimen used to acquire the geometry of the model was also used for mechanical compressive tests, with vertical and lateral loads, to validate the numerical model., Results: The peak values of stress, calculated on the outer and inner surfaces of the FRCIFPD, were localized in the connector areas. When a vertical load was applied, stress on the prepared teeth was concentrated at the cervical margin of the abutment preparation., Conclusion: Within the limitations of this in vitro study, the results suggest that within the FRCIFPD, stress concentrates at the connector areas, and that in the prepared teeth, peak stress is at the cervical margin of the box of the preparation.

Inlay fixed partial dentures luted by use of adhesive procedures offer a clinical alternative for the restoration of single missing posterior teeth. The introduction of ceromers and fiber-reinforced composites and the continuous improvement of adhesive systems and luting agents make this type of restoration possible, offering good aesthetic and functional results. The procedure is minimally invasive and conservative. This clinical report reviews the factors influencing the diagnosis and the clinical indications for an inlay fixed partial denture. In addition, a patient treatment is presented to illustrate the clinical procedures involved.

The oral and dental rehabilitation of patients with ectodermal dysplasia is a demanding and complex process. Close cooperation of medical and dental specialists is is mandatory. The individual age related situation and aspects of social integration have to be considered, when doing treatment planning for these patients. A major problem is the highly reduced number of teeth, the impaired development of the jaws and the dysplastic alteration of the teeth. The prosthodontic rehabilitation of a young girl with the congenital disease of ectodermal dysplasia is presented and discussed.

Purpose: This in vitro study was carried out to examine the fracture strength of metal- free posterior inlay fixed partial dentures (IFPDs). The 3-unit IFPDs were made of either a polyethylene fiber-reinforced composite, 3 glass fiber-reinforced composites, or an all-ceramic material., Materials and Methods: Eight IFPDs were fabricated of each material in accordance with the manufacturer's instructions and luted to extracted human molars with a dual-cure adhesive system. The molars were positioned in PMMA resin 10 mm apart mesiodistally. Inlay cavity preparations with enamel finishing lines were used. After thermal cycling and mechanical loading in an artificial oral environment, the cemented IFPDs were mechanically loaded until failure. Visual and radiologic examinations were done out to discern the different forms of fracture. Median and 25%/75% percentile values were calculated. Statistical analysis was performed using the Mann-Whitney U test and the Kruskal-Wallis test (p< or =0.05)., Results: With a median (and 25%/75% percentile) fracture strength of 368 N (234 N/424 N), the FibreKor/Conquest Sculpture showed significantly lower values than the Connect/BelleGlass [898 N (736 N/1033 N)], Vectris/Targis [723 N (692 N/806 N)], Everstick/Sinfony [634 N (532 N/673 N)], and Empress2 [520 N (385 N/706 N)]., Conclusions: Assuming maximum chewing forces of > or =500N in posterior areas, all systems showed sufficient fracture strength in most cases and warrant further investigation for potential clinical use., (Copyright 2002 by The American College of Prosthodontists.)

Purpose: This prospective clinical trial examined the effect on teeth and implants when rigidly or non-rigidly connected in a cross-arch model., Materials and Methods: Thirty patients received 2 implants, 1 on each side of the mandible, and were restored with 3-unit fixed partial dentures connected either rigidly or non-rigidly to an abutment tooth. Patients were followed for at least 5 years post-restoration., Results: Repeated-measures analysis revealed no significant difference in crestal bone loss at implants (rigid versus non-rigid methods). An overall significant difference (P < .001) was found comparing methods for teeth. Paired t tests revealed no significant differences in crestal bone levels for implants or teeth at the 5-year recall. Kaplan-Meier methods and the Cox proportional hazards model showed no differences between attachment methods with regard to success based on survival and bone loss criteria. During the 5-year recall period, 1 implant (rigid side) was removed. Four implants developed bone loss greater than 2 mm during the course of this trial. One tooth on the rigid side and 2 teeth on the non-rigid side had greater than 2 mm of crestal bone loss and were removed secondary to fractures. In all, 5 abutment teeth were removed, all of which had been treated with root canal therapy and fractured at the interface of the post within the tooth. There was no clear relationship of tooth fracture to attachment. Repeated-measures analysis of mobility values revealed no significant changes over the time course of this study, and paired t tests revealed no statistically significant differences between implants for mobility. Repeated-measures analysis and paired t tests for probing depth revealed no significant changes over the time course of this study. There were no significant differences in soft tissue indices for either attachment method. The percentage of patients who had measurable intrusion was 66% for the non-rigid group, and 44% for the rigid group; 25% of the non-rigid teeth had greater than 0.5 mm intrusion, compared with 12.5% for the rigid group. For the 2 time periods evaluated, there was no significant increase in intrusion over time. The non-rigid-side implant required more nonscheduled visits to treat problems than the rigid implant and the teeth., Discussion: Most patients were treated successfully with rigid or non-rigid attachment of implants to teeth., Conclusion: The high incidence of intrusion and non-scheduled patient visits suggest that alternative treatments without connecting implants to teeth may be indicated.

Statement of Problem: There are no studies that analyze the long-term durability of minimally invasive fixed partial dentures (FPDs) by comparing different methods of adhesive bonding., Purpose: This in vitro study examined the influence of cavity design and operative technique on the marginal adaptation of resin-bonded composite FPDs., Material and Methods: Slot-inlay tooth preparations with cavity margins located in enamel were prepared in 18 maxillary canines and 18 maxillary first molars designated as abutments. The specimens were divided equally into 3 experimental groups. In all groups, butt joint tooth preparations were created in canines and molars. In group 2, canines were prepared additionally with a 1.5-mm wide palatal bevel in enamel. After pretests with modification spaces of 11 and 17 mm (length), 2 missing premolars were replaced by the ceromer Targis and reinforced with the glass-fiber material Vectris. The prostheses were inserted with Tetric Ceram with use of an ultrasonic-supported, high-viscosity technique. Restorations were selectively bonded to cavity finish lines in groups 1 and 2 ("selective bonding"). In group 3, restorations were bonded totally to the whole cavity surface ("total bonding"). The restorations were stressed in a computer-controlled masticator. Marginal quality was examined with an SEM at x 200., Results: The percent area of optimal margins after thermomechanical loading between composite and enamel in each group was as follows: group 1, 86.2% +/- 12.3% for canines and 95.5% +/- 3.5% for molars; group 2, 95.3% +/- 2.1% for canines and 96.2% +/- 2.7% for molars; and group 3, 95% +/- 0.9% for canines and 86.4% +/- 3.2% for molars. The marginal quality for molars inserted with total bonding was significantly lower (P< or =.05)., Conclusion: Within the limitations of this study, the selective bonding technique for slot inlay-retained fixed partial dentures resulted in a negligible loss of marginal quality after extensive mechanical and thermal stress. The selective bonding technique is recommended for box-shaped cavity preparations.

Objective: The treatment procedures used in conjunction with two different metal-free restorative systems are illustrated on the basis of clinical examples. In addition, a report on the initial clinical findings is provided., Method and Materials: Metal-free restorative materials are opening doors to new preparation methods because of their close link to the adhesive cementation technique. As a result of the developments over the past few years, various metal-free systems that can be used to fabricate short-span fixed partial dentures (FPD) are now available. Certain guidelines, however, must be observed in the process. Because of their minimal invasiveness, inlay-retained FPDs offer an interesting solution in cases where the residual dentition exhibits low caries activity. Since the beginning of 1997, a total of 23 metal-free inlay-retained FPDs made of two different types of framework material (11 of high-strength pressed ceramic and 12 of fiber-reinforced composite) have been examined in a clinical study., Results: One inlay-retained FPD made of pressed ceramic had to be replaced because of a fracture. Because the materials have only been on the market for a short time, long-term results are not yet available., Conclusion: This type of restoration provides excellent esthetics and reduced invasiveness compared with complete crown-retained FPDs, although indications are limited by the special mechanical properties of the material.

A restorative design is introduced in preference to the implant-supported bar, clip, or ball-type removable prosthesis. It has been necessary to develop an alternative treatment approach to the placement and restoration of implants in the posterior mandible or maxilla. In an examination of the available therapeutic choices and their rationales, this treatment option offers greater function, esthetics, and comfort. Four maxillary and one mandibular arches were reconstructed with anterior implant-supported fixed bridges/splinted restorations and a precision partial denture design posteriorly, using an extracoronal universal ball attachment. These cases have demonstrated minimal maintenance up to 7 years in function.

When a tooth prepared for a crown does not comply with the general principles of retention and resistance form, and it is not possible to correct it without damage to the biologic structures of the tooth, consideration must be given to the purpose of the crown, such as whether it is a single crown, a retainer for a fixed restoration, or a retainer for a fixed removable prosthesis with precision attachments. The crown prepared with receptacles for internal attachments will undoubtedly require more retention and resistance to dislodgment than a single crown because of forces that will be applied to it through the removable portion of the restoration. The purpose of this article is to present an alternative procedure that uses the intracrown ring, which provides additional retention for the abutment crown because of the compressible ring. The compressible ring is placed in the groove prepared in the lower third of the abutment during the crown preparation.

Multiple-cantilevered pontic bridges can be a great alternative to dental implants and distal extension prostheses. Dental hygiene must be considered the most important factor in preserving the status quo of the permanent restoration. Traumatic occlusion, which can occur because of the widened periodontal space and greater mobility of a multiple-cantilever bridge, is not automatically a sign of failure. As long as the mobility of the fixed bridge does not increase and the patient can function and feel comfortable with it, a successful therapy can be concluded. If marginal periodontitis exists, destruction of the cervical ligaments, bone resorption, and apical migration of the epithelium will occur. Through loss of the supportive structures, hypermobility will increase. If the destructive factors of marginal periodontitis are not eliminated, the hypermobility can interfere with masticatory function. It is important that patients be made aware of this possibility. Regular recalls in the beginning of the maintenance program will emphasize the importance of the home-care system.

Porcelain fused to metal provides better aesthetics in fixed partial dentures than veneers with gold-resin that were used formerly. The aim of our study was to evaluate complications and primary failures of fixed metal ceramic bridge prostheses made by dental students. We studied 61 patients (32 women, 29 men, mean age 49 years, range 28-73 years) treated during years 1990-1993. Data were collected from the patient files. Altogether 82 bridges were made (mean 4.1 units, range 2-6), 221 abutments (mean 2.7, range 2-6) and 136 pontics (mean 1.6, range 1-4). Forty-seven cast cores were used in 29 bridges (mean 0.4 cores, range 1-3) and semiprecious attachments as an extra attachment in two bridges. Seven teeth were extracted due to complication and/or failure during endodontic treatment and root canal perforation during preparation. In two cases the abutment tooth was fractured by removing the old crown. Four unsuccessful bridges were remade and in seven cases the firing of porcelain was renewed. The study concludes that most common failures of fixed metal ceramic bridges made by dental students occur during root canal preparation of abutment teeth.

Statement of Problem: Controversy regarding the connection of implants to natural teeth in fixed partial dentures has emerged in response to clinical reports of intrusion of the natural teeth. Although theories have been proposed to explain this phenomenon, the cause of the intrusion remains unknown. Numerous longitudinal studies have demonstrated that teeth can be successfully connected to implants. The use of rigid connectors, or nonrigid connectors with the keyway on the implant, are described as mechanisms to prevent intrusion of the natural tooth., Purpose: This article reviews the literature that pertains to this subject and includes treatment modalities that may be helpful in preventing intrusion.

The survival rate and the reasons for failures of 130 combined fixed-removable reconstructions (CFR), incorporated in 112 patients, were assessed. Each CFR reconstruction was classified depending on its attachments: 76 reconstructions were attached with rigid, precise attachments, and constituted the rigid group; 54 reconstructions were attached with either semi-precision or individual attachments and were defined as the semi-rigid group. Of the 130 reconstructions, 41 were determined as complete successes, 39 as partial successes and 50 as failures, leading to 37 major repairs and to 13 new reconstructions. Three reconstructions failed due to technical reasons, 36 due to biological reasons and for 11 reconstructions, both categories of reasons were responsible for their failure. In total, technical reasons were counted 15 times in comparison to 73 biological reasons for those 50 failed reconstruction, with 29 fractured abutment teeth as the most common biological reason. Within the rigid group, 45 failed reconstructions were observed, whereas within the semi rigid group only 5 failures occurred, leading to an 8-year survival estimate (+/- SD) of 30.1% (+/- 6.9%) for the rigid group and 93.1% (+/- 3.9%) for the semi rigid group. Beside the attachment type, the anatomy of the partially edentulous tooth arch in form of the free-end situation and the dentate opposing jaw were identified as risk factors.

This article describes a procedure that uses the Ney MS (Minimal Space) intracoronal attachment as an interlock in a pontic. This procedure overcomes the disadvantages associated with the use of the intracoronal attachments, which are (1) excessive tooth reduction often required to place the attachment within the contour of the crown; (2) compromised embrasures, which result in oral hygiene and periodontal problems; and (3) poor esthetics.

In the posterior partially edentulous jaw, implants may be used to supplement existing natural dentition. Frequently, the maxillary sinuses and the mandibular nerve preclude the fabrication of freestanding implant-retained prostheses. However, if an implant and a natural abutment are combined, a fixed prosthesis can be fabricated, restoring the arch into the premolar area. The histories of three patients with attachments connecting implant-retained ceramotitanium crowns with crowns on natural abutments are described. A design for a rigid custom-made attachment for the Brånemark system, using standard components with a machine-duplication, spark-erosion technique, is suggested.

When the abutment teeth of a fixed partial denture are severely misaligned, insertion of the prosthesis becomes more difficult. Some of the methods traditionally recommended to overcome the problems associated with this situation are examined. One design that simplifies treatment and improves the prosthesis is suggested.

Despite careful attention, implants occasionally are placed at less than ideal angles. A combination of techniques can be implemented in the laboratory to correct malalignment. The "thread-timed impression" technique to assist with these restorations is described.

The authors have examined a precision attachment recently invented in Hungary. They are reporting about the experience gained during clinical examination of dentures made in different classes on the basis of the Fábián and Fejérdy classification of partial edentulousness.

When implants and natural teeth are combined, forces on the abutments need to be controlled so that neither the teeth nor the implants sustain excessive amounts of force. The technique described addresses reduction of potentially harmful cantilever effects in a fixed prosthesis that is facultatively removable. A nonrigid attachment is used in the implant crown. Telescopic copings are definitively cemented on the natural teeth. Provisionally cemented overcastings incorporate this nonrigid connection between the pontics and the implant crowns. The means of connection employs a semiprecision attachment in which the female connector is placed within the relatively immobile implant crown. The male connector is placed on the pontic seating into the implant crown. This relationship limits cantilever forces exerted on the natural-tooth abutment. The nonrigid connection of the tooth-supported retainer limits cantilever forces and directs occlusal loads axially in a direction along the long axis of the implant. This arrangement is acceptable as compared to the complete tooth-supported arrangement described by Shillingburg; in this situation, the implant will not migrate. Since 1986, this arrangement has been used clinically without attachment migrations, implant failure, or endodontic therapy, with only minor screw-loosening episodes.

The design and fabrication of multi-unit fixed prostheses where abutment teeth are misaligned have been difficult technical challenges for dentists and dental technicians. There have been a number of methods developed to attain a common path of insertion, including modified preparation designs, telescopic copings placed on abutments to correct alignment, adhesively retained bridge frameworks, and mechanical precision attachments between sections of a segmented prosthesis. This paper describes a method of fabricating a precision attachment on a segmented prosthesis that can be rigidly fixed after cementation. The technique involves the use of a cast tapered pin to permanently attach the prosthesis segments together. All parts can be fabricated by conventional lost-wax techniques with a minimum of instrumentation. The technique has the added advantage of being reversible should the prosthesis ever need to be separated for repair or recementation.

The implant-supported, maxillary anterior, fixed-detachable prosthesis is often fabricated with a gingival flange to enhance esthetics and phonetics. However, only the dentist can remove the prosthesis, and the esthetic labial flange invariably impedes patient access for cleaning. A two-piece, fixed-detachable prosthesis that incorporates a substructure retained with conventional set screws and a superstructure retained with precision attachments has been developed. The substructure is contoured to facilitate patient access for oral hygiene because it will be covered by the superstructure and neither esthetics nor phonetics is a concern. The superstructure is easily removed by the patient for routine cleaning and can be designed for favorable esthetics and phonetics. This article reviews and describes the procedures for fabrication of this precision attachment-retained, implant-supported prosthesis.