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A discussion of the rationale and requirements of the provisional restoration in fixed prosthetic dentistry has been presented. The imporatnce of this phase of restorative densitry and a survey of techniques for making interim restorations were gleaned from a review of the literature. A method for the fabrication of a provisional fixed partial denture using an acrylic resin interocclusal record was described and illustrated.
INTRODUCTION: The aim of this study was to examine the clinical performance of this method, and determine which temporary cement was the most appropriate. METHODS: Dental fixtures (Tiolox implants GmbH, Germany) were implanted and crown and bridgework applied in a private practice between 1998 and 2003. Copings made of pure gold or titanium were permanently cemented onto the prepared teeth. The bridges were attached with either conventional temporary cements (Zinc oxide/ calcium hydroxide based) or acrylic/urethane cement (IMProv) both to the copings and to the implant abutments. Complications were evaluated by a retrospective review in January 2006. RESULTS: A total of 47 patients (response: 81%) with 65 fixed partial dentures could be evaluated. Removal and re-attaching without damage of the dentures was undertaken for the following reasons: for follow-up examinations (n = 31), colour corrections (n = 15), cleaning of the dentures (n = 12), treatment of peri-implantitis (n = 2), repair following ceramic fractures (n = 5), implant failure (n = 1), tooth extractions (n = 2), root canal treatments (n = 2), occlusal corrections (n = 2), or in the case of abutment loosening (n = 4). Accidental detachments with conventional temporary cements occurred more frequently and more rapidly than with IMProv (15% versus 88.7% survival rate after four years). CONCLUSIONS: This method for dental implant supported fixed partial dentures is successful and efficient.
A two dimensional mathematical model was generated, representing a three unit fixed-fixed partial denture and its supporting structures. Second premolar and second molar were used as abutments with first molar as pontic. A load of 1 kg was applied to the occlusal surface of the casting. Stresses and displacement developed at various regions were analyzed with STAAD III/ISDS program. Maximum stresses were developed in the pontic and connectors with distal connector experiencing the maximum stresses. Stresses transmitted to the dentin were comparatively lower and more of compressive in nature. The underying bone experienced moderate amount of both compressive and tensile stresses but the displacement in this tissue were minimal compared to the rest.
A method for using the functionally generated-path technique to fabricate full occlusal porcelain-fused-to-metal fixed partial dentures and crowns has been described. Proper use of this technique in carefully selected patients should eliminate occlusal adjustments and the concomitant polishing and glazing that are often necessary before the restoration can be permanently cemented.
In recent years, there has been an increasing interest in fixed partial dentures (FPD) quality, expected lifetime and possible reasons for failure. This study probed the FPD success rate and the relationship among various factors and their effect on FPD failure. Patients treated by dental students under supervision and installed FPDs were examined clinically and radiographically. A total of 247 FPDs were evaluated after a mean service period of 6.3 years (ranging from 1 to 25 years) after cementation. Caries was found to be the most frequent cause of failure and non-vital abutments decreased survival rates.
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.
BACKGROUND: The authors conducted a study to examine the clinical performance of two-unit cantilevered resin-bonded fixed partial dentures (RBFPDs) that were inserted at The Prince Philip Dental Hospital, University of Hong Kong. METHODS: The authors recalled patients who had received two-unit cantilevered RBFPDs at least 24 months before the recall examination. The authors recorded the following data: patient's sex and age, operator's experience, prosthesis cementation date, endodontic treatment if performed, bone support, tooth mobility, the presence of shim-stock contacts on the abutment or pontic in intercuspal position, and the presence of aproximal axial contacts adjacent to the prosthesis. They also recorded the date of any debonding with subsequent treatment. They asked the patients qualitative questions about their prostheses. RESULTS: A total of 269 prostheses were placed in 214 patients and had a mean service life of 51.7 months +/- 19.5 months standard deviation, with a range of 13.2 to 141.6 months. Of 14 failed prostheses, 12 debonded, resulting in a success rate of 94.8 percent and clinical retention rate of 95.5 percent. No discernable rotation or drifting of the abutments was apparent in any of the prostheses. Overall patient satisfaction with RBFPDs was good, with an average assessment score of 8.5. CONCLUSIONS: The authors observed a 95.5 percent clinical retention rate of 269 two-unit RBFPDs, with no apparent drifting of the abutments. Longer-term follow-up studies are required. CLINICAL IMPLICATIONS: Two-unit RBFPDs are conservative and clinically retentive prostheses in the short to medium term.
PURPOSE: The purpose of this study was to determine the fracture resistance of three-unit fixed partial dentures (FPD) made of new core ceramics. MATERIALS AND METHODS: A base metal three-unit master FPD model with a maxillary premolar and molar abutment was made. Tooth preparation showed 0.8-mm circumferential and 1.5-mm occlusal reduction and a chamfer margin design. FPDs were constructed with a uniform 0.8-mm-thick core ceramic and a porcelain veneer layer. In-Ceram Alumina, In-Ceram Zirconia, and DC-Zirkon core ceramics were machined by a computer-aided design/manufacturing system, whereas IPS Empress 2 core ceramic was indirectly built up using the fabrication technology of waxing and heat pressing. FPDs of IPS Empress were heat pressed as complete restorations without core material. To ensure standardized dimensions, the FPDs were controlled at different points. All FPDs were cemented with ZnPO4 on the master model and loaded on a universal testing machine until failure. The failure load and mode of failure were recorded. RESULTS: The highest failure loads, exceeding 2,000 N, were associated with FPDs of DC-Zirkon. FPDs of IPS Empress and In-Ceram Alumina showed the lowest failure loads, below 1,000 N, whereas intermediate values were observed for FPDs of IPS Empress 2 and In-Ceram Zirconia. Differences in mean values were statistically significant. CONCLUSION: The high fracture resistance evaluated for FPDs made of DC-Zirkon underscores the remarkable mechanical properties of high-performance ceramic, which could be useful for highly loaded all-ceramic restorations, especially in the molar region.
PURPOSE: The aim of this in vitro study was to evaluate the marginal adaptation and retention of inlay fixed partial dentures (IFPDs) made with 1 fiber-reinforced composite and 2 different ceramic materials using quantitative scanning electron microscope analysis after thermal cycling and mechanical loading, which simulated approximately 5 years of oral service. MATERIALS AND METHODS: Eighteen IFPDs made with fiber-reinforced composite (SR Adoro/Vectris), zirconium oxide-TZP (Cercon), and magnesia partially stabilized zirconia (DC-Leolux) covered with silica-based ceramics were tested in this study. The specimens were mechanically loaded in the vestibular cusp of the pontic element in a computer-controlled masticator with 1,200,000 half-sinusoid mechanical cycles of maximum 49 N each at a frequency of 1.7 Hz. A total of 3,000 thermocycles at 5 degrees C and 55 degrees C, 2 minutes each, were performed simultaneously. The marginal adaptation was analyzed at the interface of the luting composite and the abutment inlay/onlay (CI) and at the interface of the tooth and the luting composite (TC). RESULTS: The percentages of continuous margin at the CI interface were 94.6 +/- 3.1 and 88 +/- 6.7 for Adoro/Vectris, 92.9 +/- 5 and 85.7 +/- 6.1 for Cercon, and 96.2 +/- 2.1 and 82.2 +/- 9.8 for DC-Leolux, respectively, before and after loading. The percentages of continuous margin at the TC interface were 86.7 +/- 6.7 and 62.5 +/- 16.4 for Adoro/Vectris, 93.3 +/- 3.4 and 83.2 +/- 5.9 for Cercon, and 96.1 +/- 2.4 and 75.3 +/- 7 for DC-Leolux. Statistically significant differences were found after loading between the fiber-reinforced composite and the 2 ceramic systems at the TC interface. CONCLUSION: Within the limitations of this experimental study with regard to the sample size and contacting vectors, the results showed that flexibility of the framework may play an important role in the marginal adaptation of the IFPDs. More rigid materials may transfer less stress to the margins, thus promoting a more stable adhesion to the dental tissues.
Gas-plasma-treated, woven polyethylene fabric to reinforce heavily filled composite resin was used to fabricate a direct/indirect fixed partial denture to esthetically replace a missing maxillary central incisor for a 12-year-old boy. The patient and his parents were interested in using a fixed prosthesis as an interim space-maintaining restoration, which would boost the patient's self-esteem. The technique used was an amalgamation of old concepts and new procedures that enable general dentists to expeditiously and inexpensively replace missing teeth. This relatively noninvasive and basically reversible procedure allows the patient to ponder the final restoration as he or she goes through growth, development, and maturation of the hard and soft tissues.
PURPOSE: The purpose of this review was, first, to critically evaluate published evidence on the effects of artificial crowns and fixed partial dentures (FPDs) on adjacent periodontal tissue health, and second to synthesize this evidence into meaningful summaries. Restoration qualities that contribute to inflammatory responses were identified based on strength of evidence, and variables that should be controlled in future investigations were outlined. Such information is necessary to accurately predict the prognosis of periodontal tissues adjacent to crowns or FPDs. METHODS: Clinical trial and epidemiologic evidence published in English was collected. The effects of crowns or FPDs on gingival inflammation, probing depths, and bone loss were evaluated based on accuracy of measurement, reliability of measurement, and/or appropriateness of data analysis. RESULTS: Crowns and FPDs increased the incidence of advanced gingival inflammation adjacent to restorations, particularly if restorations had intracrevicular finish line placement, poor marginal adaptation, or rough surfaces. However, because of the limitation in the accuracy and reliability of probing depth measurements, reports of greater mean probing depths of crowned teeth, which tended to be less than 1 mm greater than control teeth, should be questioned. Finally, crowns and FPDs in general did not accelerate the rate of adjacent bone loss. CONCLUSION: Clinically deficient restorations, as well as clinically acceptable restorations, can contribute to gingival inflammation. However, with the limitations of the applied methods of measurement, current evidence has not shown an increased attachment loss adjacent to crowns or FPDs. Future trials should document periodontal health before therapy and periodically after restoration insertion so that each tooth serves as its own control. In future studies, the periodontal disease history of the patient, the influence of the restoration on plaque formation, and the composition of the crevicular microflora must be recorded.
The study aimed to investigate occlusal factors in fixed partial dentures (FPDs) still in service for more than 10 years, and to assess the patients' opinions regarding oral function with these constructions. Thirty-four patients with 43 FPDs were examined clinically concerning occlusion and by means of a questionnaire on functional aspects. The most common occlusal contact pattern was group function (51% on both sides, 7% on one side) while canine protected occlusion was recorded in 16% on both sides, 7% on one side. Balanced occlusion (19%) was mainly found when the FPD occluded against a complete denture and when there were few abutments and a small amount of abutment supporting tissue. The number and intensity of the occlusal contacts were assessed by means of thin occlusal sheets (50 microns). On average, one occlusal contact was observed on each dental unit with antagonist. The average number of sheets that could be introduced between the antagonists when the patient bit hard in the intercuspal position was two without significant differences between different areas (anterior/posterior) or type of dental unit (abutment, pontics, cantilever section). In the cantilever sections there were looser contacts (more interocclusal sheets) more distally. The great majority of patients were satisfied with the function of their FPDs (mastication, phonetics, aesthetics, comfort, and hygiene). Subjective function was not significantly influenced by FPD design, occlusal factors or number of FPD units. The only significant difference observed was that patients with a small amount of supporting tissues said they had more difficulties with hard foods than the others had. Although a stable occlusion was found in all FPDs, none of the other occlusal parameters examined were related to the long-term results.
In this study, the effect on the fracture load of inlay-retained composite fixed partial dentures (FPDs) caused by reinforcing them with fiber-reinforced composite (FRC) in different positions was examined. Experimental FPDs were fabricated using Estenia/EG Fiber (Kuraray Medical). Pontic reinforcement was then performed in one of the following three ways: reinforced the central area in a single line or in double straight lines, or reinforced the bottom in a curved line. The finding was that, when the area ranging from the connector to the bottom of the pontic was reinforced with FRC in a curved line, the fracture load of the FPDs tended to become higher. In addition, the FPDs fractured mainly at the veneering composite of the connector area. Based on the results of this study, it was concluded that reinforcement using FRC is effective, and that the veneering composite in the connector area needs to have sufficient strength to prevent the fractures.
PURPOSE: The aim of the present clinical study was to analyze the long-term treatment outcome of fixed partial dentures (FPD) with cantilevers. MATERIALS AND METHODS: Ninety-two patients with 115 cantilever FPDs on 239 abutment teeth were examined. Immediately following cementation, radiographs of the abutment teeth were obtained. At the follow-up examination 5 to 16 years after cementation, the abutment teeth were clinically and radiographically evaluated. Besides the assessment of periodontal parameters and vitality testing, the presence of carious lesions of the abutment teeth, loss of retention, fracture of bridgework, and fracture of abutment teeth were also recorded. The Student's t test was used to detect differences between abutment teeth and control teeth with natural crowns as well as over time within the groups. RESULTS: Plaque scores and bleeding on probing were low at both abutment and nonabutment teeth. Mean probing pocket depth and level of the clinical attachment never exceeded 3.0 mm in both groups. The radiographic bone levels at abutments were stable within 3% over the observation period. Of the 120 initially vital abutment teeth, 12 (10%) lost vitality during the observation period; one (1%) of the 119 initially nonvital abutments showed periapical pathology. Development of secondary caries was observed at 8% of the 239 abutment teeth. In total, 8% of the abutment teeth were affected by loss of retention, which made up more than half of all technical problems. Material fractures only occurred occasionally, affecting from 1% to less than 3% of the abutment teeth. Fracture of abutment teeth amounted to 3% and was twice as frequent at abutments adjacent to cantilevers compared to abutments not adjacent to cantilevers. CONCLUSION: The most frequent biologic (caries) and technical complications (loss of retention) made up more than half of all problems recorded. These problems may be at least partially avoided by performing optimal plaque control and by strictly observing the rules for preparation of retentive FPD abutments.
OBJECTIVE: To explore a computer aided design (CAD) route for the framework of domestic fixed partial denture (FPD) and confirm the suitable method of 3-D CAD. METHODS: The working area of a dentition model was scanned with a 3-D mechanical scanner. Using the reverse engineering (RE) software, margin and border curves were extracted and several reference curves were created to ensure the dimension and location of pontic framework that was taken from the standard database. The shoulder parts of the retainers were created after axial surfaces constructed. The connecting areas, axial line and curving surface of the framework connector were finally created. RESULTS: The framework of a three-unit FPD was designed with RE technology, which showed smooth surfaces and continuous contours. CONCLUSIONS: The design route is practical. The result of this study is significant in theory and practice, which will provide a reference for establishing the computer aided design/computer aided manufacture (CAD/CAM) system of domestic FPD.
This study examined the influence of medial implant location in three-unit posterior cantilever fixed partial dentures (FPDs) on stress distribution in mandibular bone surrounding two implants. A three-dimensional finite element model that included three-unit FPD and two cylindrical-type implants (4 mm in diameter and 10 mm in length) osseointegrated in the posterior mandible, was digitized. Five different models were created according to the medial implant location between the missing second premolar and the first molar location. The distal implant was fixed at the missing second molar location. Oblique bite force of 100 N at 30 degrees buccal to the vertical direction was directed on each of three artificial teeth, respectively and simultaneously, while the lower surface of the mandible was fixed. The maximum equivalent stress in the cortical and the trabecular bone generally increased as the medial implant shifted to a distal position. Under the simultaneous bite force, relatively low maximum stresses within the cortical bone: between 55 MPa and 57 MPa, were shown in the models with the medial implant placed within the range of one implant diameter from the most medial position, while higher maximum stresses: between 64 MPa and 73 MPa, were demonstrated with more distally placed medial implants. The results suggest that reasonably low mechanical stress in the surrounding bone may be assured when the medial implant is placed in the range between the missing second premolar position and one implant diameter distal from that location.
A uncomplicated clinical procedure to enhance the retention of posterior resin-bonded fixed partial dentures was described. This method involves some modifications to the preparation and casting design and requires slightly more time and attention at the cementation stage of the prosthetic treatment.
This in vitro study was carried out in order to estimate the clinical usability of adhesively luted three-unit posterior fixed partial dentures (FPD) made of a polyethylene-fibre-reinforced-composite system (PFRC) in comparison with a glass-fibre-reinforced-composite system (GFRC). Therefore the fracture strength and marginal adaptation were examined. A total of 16 FPDs of each material combination were manufactured and adhesively luted to human molars. Before and after an artificial ageing process by thermal cycling and mechanical loading (TCML) the quality of the marginal adaptation was examined by evaluating epoxy replicas in a scanning electron microscope (SEM). After TCML the fracture strength of eight FPDs of each series was tested by mechanical loading them to failure. With the remaining eight FPDs the quality of deeper layers of the luting was examined with a dye penetration technique. The calculated median fracture strength values (25/75% percentiles) were 830 N (643/982) for the PFRC and 884 N (684/1,113) for the GFRC. The SEM analysis showed at least 80% of perfect marginal areas for both material combinations in dentine as well as in enamel before and after TCML. Looking at the cement-tooth interfaces the dye penetration technique showed statistically significant better results for the enamel finishing lines than for those in dentine. With finishing lines in dentine the two material combinations showed statistically significant differences for this interface. Fracture force results as well as marginal quality encourage further clinical investigations on both systems although the GFRC performed slightly better than the PFRC.