Post-endodontic treatment of incisors and premolars among dental practitioners in Saarland: an interactive Web-based survey.

OBJECTIVES: The aim of the present study was to evaluate the trend of dental practitioners in the federal state of Saarland in Germany in regard to restoring endodontically treated teeth using a Web-based survey. MATERIALS AND METHODS: An interactive Web-based survey instrument was developed, including seven clinical scenarios, presented by photographs of natural incisor and premolar with different types of cavities. Following a decision tree adapted to the clinical treatment, questions on different aspects of the post-endodontic treatment were asked. All 615 members of the Saarland Dental Association (SDA) were asked to participate in the survey. RESULTS: A total of 33 % completed the survey. The majority of the participants believed in the reinforcement effect of the ferrule design, as well as the post placement. The vast majority of the responding practitioners (92 %) adapted their treatment strategies to a high extent to the destruction degree of the endodontically treated tooth. Fiber-reinforced composite (FRC) posts are the most popular prefabricated post type, regardless of the cavity size and tooth localization. Significant differences between the dentists according to the degree of experience were detected only for the use of glass-ionomer cements as core buildup material. CONCLUSIONS: The predominant post-endodontic treatment strategies of German dental practitioners are only partly in agreement with the current literature. There is a clear trend toward the increasing use of metal-free post and core materials. CLINICAL SIGNIFICANCE: Although the participants showed a general adoption of modern materials and techniques, different patterns of post-endodontic treatment were revealed that were not consistent with approaches supported by the literature.

Pre-fabricated zirconium dioxide implant abutments for single-tooth replacement in the posterior region: success and failure after 3 years of function.

OBJECTIVE: Zirconia implant abutments have gained a much broader clinical use over the past few years. The aim of the present study was to assess the clinical performance of a pre-fabricated zirconium dioxide implant abutment for single-tooth replacement in the posterior region. MATERIALS AND METHODS: Forty implants of the XiVE(®) S plus screw type (DENTSPLY Friadent, Mannheim, Germany) were inserted in the posterior region of 24 patients and provided with zirconium dioxide abutments (FRIADENT(®) CERCON(®) Abutment, DENTSPLY Friadent). The following parameters were used to document the state of soft tissue: modified plaque index, modified sulcus bleeding index and pocket depth. Mesial and distal bone levels were determined on radiographs during the prosthetic treatment and at the 36-month recall. RESULTS: Thirty-seven implants could be followed up after 36 months in function. One patient wearing two abutments was lost to follow-up. One abutment exhibited a rotational misfit after 2 years in function. A further abutment showed the same failure at the 36-months recall appointment. In the remaining 36 implants the soft and hard tissue parameters were indicative of a low inflammatory status. Compared to the baseline situation, a partly significant bone apposition could be observed. Chipping of parts of the veneering ceramic was registered in 22% of the remaining implant restorations. CONCLUSIONS: The use of zirconia abutments in this study lead to mainly healthy peri-implant hard and soft tissue conditions but, considering the observed failures after 3 years in function, clinical long-term results should be awaited before recommending full zirconia implant abutments in a posterior indication.

Clinical success rates for polyether crown impressions when mixed dynamically and statically.

The purpose of this study is to compare success rates of dual-viscosity impressions for two types of mixing techniques of the polyether elastomeric impression material. Additionally, influencing parameters on the success rates should be evaluated. The expectation was that there would be no difference between the success rates for the two mixing techniques. Two centres enrolled 290 subjects (727 teeth) into the trial. Patients were randomized for the two types of mixing techniques. One step, dual-viscosity impressions were made with either statically mixed Impregum Soft tray material (SAM) or dynamically mixed Impregum Penta H DuoSoft (DMM). Low viscosity Impregum Garant L DuoSoft was used for both groups. Gingival displacement involved the use of two braided cords. Full-arch trays were used exclusively. Both critical defects and operator errors were assessed for the first impression taken by trained dentists. The primary outcome was impression success. For comparison of the two mixing techniques, the odds ratio for success and the corresponding one-sided 95% confidence interval was calculated by a logistic regression model. To account for the dependence between several teeth within one patient, the method of general estimating equations was used. The overall impression success rate was 35.4%. Both mixing techniques showed equal success rates indicated by an OR of 1.0 and a lower limit of the one-sided 95% confidence interval of 0.71. Using this result to develop the corresponding interval for the difference, it could be shown that the success rate using SAM was at most 8.2% lower than that when using DMM with a probability of 95%. Multivariate logistic regression analysis of other potential influencing factors showed position of finish line (p = 0.008, supra compared to mixed), blood coagulation disorder (p = 0.021) and the level of training of the clinician (student vs dentist, p=0.008) to have an independent influence on the success rate. Dynamic mechanical mixing and the new static mixing of polyether tray material showed nearly equal success rates in the study even though success rates were comparatively low (DMM, 35.3%; SAM, 35.4%).

Fracture behavior of straight or angulated zirconia implant abutments supporting anterior single crowns.

The aim of the study was to evaluate the influence of artificial aging on the fracture behavior of straight and angulated zirconia implant abutments (ZirDesign™; Astra Tech, Mölndal, Sweden) supporting anterior single crowns (SCs). Four different test groups (n = 8) representing anterior SCs were prepared. Groups 1 and 2 simulated a clinical situation with an ideal implant position (left central incisor) from a prosthetic point of view, which allows for the use of a straight, prefabricated zirconia abutment. Groups 3 and 4 simulated a situation with a compromised implant position, requiring an angulated (20°) abutment. OsseoSpeed™ implants (Astra Tech) 4.5 mm in diameter and 13 mm in length were used to support the abutments. The SCs (chromium cobalt alloy) were cemented with glass ionomer cement. Groups 2 and 4 were thermomechanically loaded (TCML = 1.2 × 106; 10,000 × 5°/55°) and subjected to static loading until failure. Statistical analysis of force data at the fracture site was performed using nonparametric tests. All samples tested survived TCML. Artificial aging did not lead to a significant decrease in load-bearing capacity in either the groups with straight abutments or the groups with angulated abutments. The restorations that utilized angulated abutments exhibited higher fracture loads than the restorations with straight abutments (group 1, 280.25 ± 30.45 N; group 2, 268.88 ± 38.00 N; group 3, 355.00 ± 24.71 N; group 4, 320.71 ± 78.08 N). This difference in load-bearing performance between straight and angulated abutments was statistically significant (p = 0.000) only when no artificial aging was employed. The vast majority of the abutments fractured below the implant shoulder.

Influence of artificial aging on the load-bearing capability of straight or angulated zirconia abutments in implant/tooth-supported fixed partial dentures.

PURPOSE: The aim of the study was to evaluate the influence of artificial aging on the fracture behavior of straight and angulated zirconia implant abutments used in ZirDesign (Astra Tech) implant/tooth-supported fixed partial dentures (FPDs) in the maxilla. MATERIALS AND METHODS: Four different test groups (n = 8) representing anterior implant/tooth-supported FPDs were prepared. Groups 1 and 2 simulated a clinical situation with an ideal implant position (maxillary left central incisor) from a prosthetic point of view, which allowed for the use of a straight, prefabricated zirconia abutment. Groups 3 and 4 simulated a situation with a compromised implant position that required an angulated (20-degree) abutment. OsseoSpeed implants (4.5 3 13 mm, Astra Tech) as well as metal tooth analogs (maxillary right lateral incisor) with simulated periodontal mobility were mounted in polymethyl methacrylate. The FPDs (chromium-cobalt alloy) were cemented with glass ionomer. Groups 2 and 4 were thermomechanically loaded and subjected to static loading until failure. Statistical analysis of force data at the fracture site was performed using nonparametric tests. RESULTS: All samples survived thermomechanical loading. Artificial aging did not lead to a significant decrease in load-bearing capacity in either the straight abutments or the angulated abutments. The restorations that used angulated abutments exhibited higher fracture loads than the restorations with straight abutments (group 1: 209.13 ± 39.11 N; group 2: 233.63 ± 30.68 N; group 3: 324.62 ± 108.07 N; group 4: 361.75 ± 73.82 N). This difference in load-bearing performance was statistically significant, both with and without artificial aging. All abutment fractures occurred below the implant shoulder. CONCLUSIONS: Compensation for angulated implant positions with an angulated zirconia abutment is possible without reducing the load-bearing capacity of implant/tooth-supported anterior FPDs.

[Implant-borne prosthesis for an edentulous maxilla with a large maxillectomy defect--a step-wise therapy concept]. / Implantatgetragene Versorgung eines ausgedehnten Resektionsdefektes der Maxilla. Ein mehrstufiges Therapiekonzept.

Due to the great variety of maxillectomy defects standardized restorative treatment protocols are rarely documented. For the practitioner it is from highest importance to consider the specific defect morphology and, even more important, the individual needs of affected patients. The presented case shows the planning and realization of the restoration of a maxilla with an extended resection defect following tumor surgery. Because the demanding patient remained edentulous after extraction of the residual teeth for periodontal reasons, an implant retained obturator prosthesis was inserted. Following interdisciplinary planning a treatment protocol with stepwise extraction, augmentation and implant insertion in the os zygomaticum as well as in the residual alveolar ridge was carried out, which make successive adjustment of the temporary obturator prosthesis possible. This procedure resulted in a long lasting treatment duration, but made also a sufficient temporary restoration during healing periods feasible. The definitive restoration was retained by a bar splinting four implants in the residual alveolar ridge and a special retentive anchoring abutment on two implants in the os zygomaticum.

[Implant-supported prostheses for the edentulous patient after partial maxillectomy--clinical considerations in the choice of retention elements--2 case reports]. / Implantatgestützte Restauration der zahnlosen, teilresezierten Maxilla. Klinische Uberlegungen zur Auswahl prothetischer Halteelemente--2 Kasuistiken.

The prosthetic rehabilitation of edentulous patients following hemimaxillectomy proves to be functionally unsatisfactory in many cases because of a heavily changed oral morphology and oral communication with the nasal and maxillary sinus cavities, which makes it difficult to achieve a sufficient retention and stability of the restoration using a conventional obturator denture. Using implants as anchorage increases comfort considerably for patients wearing such restorations. Due to the wide variety of the individual anatomy of the defect area and the residual parts of intact maxilla clinicians are confronted with advanced challenges according the preprosthetic planning and technical realization. Moreover, a close interdisciplinary cooperation between prosthetic dentistry and maxillofacial surgery is necessary to guarantee a successful treatment. By the means of two patients the rehabilitation with implant-borne dentures is demonstrated. Considering individual demands one patient was treated with telescopic crowns, the other with a bar system. The procedure of the prosthetic rehabilitation is presented. Aspects which arise from the specific case situations should be of special interest. In spite of the problematic initial situation the rehabilitation of the patients resulted in esthetically and functionally sufficient restorations.

Influence of fatigue testing and cementation mode on the load-bearing capability of bovine incisors restored with crowns and FRC posts.

The aim of the study was to evaluate the influence of fatigue and cementation mode on the fracture behaviour of endodontically treated bovine incisors restored with fiber-reinforced-composite (FRC) posts and crowns. Forty-eight endodontically treated incisors were restored with FRC posts, composite build-ups, and cast crowns. In 16 teeth, each of the posts were cemented conventionally with KetacCem (3M Espe) or adhesively with Panavia F (Kuraray) or RelyXUniCem (3M Espe). One-half of the specimens in each group were subjected to thermal cycling with 10,000 cycles at 5-55°C and mechanical aging, loading the specimens in 1,200,000 cycles with 50 N. Fracture resistance was determined by loading the specimens until fracture at an angle of 45°. The loading test showed that cementation mode and fatigue testing had an influence on the load bearing capability. Before fatigue testing no statistically significant differences between the different cementation modes could be detected. After fatigue testing, conventionally cemented FRC posts lead to statistically significant higher fracture loads compared to adhesively luted posts. Most specimens fractured in a favourable way, independent from the type of cementation.

Zirconium dioxide implant abutments for posterior single-tooth replacement: first results.

BACKGROUND: Prefabricated implant abutments made of zirconium dioxide (yttria-stabilized polycrystalline tetragonal zirconia; Y-TZP) have proved to be useful in the esthetically demanding anterior region and may also be useful for premolar and molar replacement because of their obvious positive impact on the health of peri-implant soft tissues. METHODS: Forty screw implants were inserted in the posterior region of 24 patients and provided with prefabricated all-ceramic abutments made of zirconium dioxide Y-TZP. Zirconia-based crowns were used as superstructures. The following parameters were used to document the state of soft tissue: the modified plaque index (mPI), sulcus fluid flow rate (SFFR), modified sulcus bleeding index (mSBI), and probing depth (PD). Additionally, implant stability was measured using an electronic mobility testing device. RESULTS: All implants (N = 40) followed up after 6 months in function were osseointegrated and showed good stability. In the presence of good oral hygiene (mPI: 0.3), the parameters SFFR (16) and mSBI (0.7) were indicative of stable and healthy soft tissue. The mean PD was highest at the distal points of measurement (2.4 mm) and was generally at a low level. Neither implant loss nor crown fractures occurred. Chipping of parts of the veneering ceramic was registered in three cases (7.5%). CONCLUSIONS: After 6 months in function, no mechanical failure was registered in any of the all-ceramic abutments. On clinical investigation, the peri-implant soft tissues were largely healthy and devoid of inflammation.

Clinical evaluation of pulpless teeth restored with conventionally cemented zirconia posts: a pilot study.

STATEMENT OF PROBLEM: Adhesive resin cements are commonly used to lute all-ceramic posts despite limited scientific data on the clinical effectiveness of using bonding agents within prepared root canals. PURPOSE: The purpose of this study was to retrospectively evaluate the clinical performance of conventionally cemented zirconia posts. Loss of retention, fracture of posts, and fracture of teeth were evaluated. MATERIAL AND METHODS: Thirty pulpless teeth in 22 patients were treated with zirconia posts. With the exception of 3 situations in which posts were inserted directly and the access openings were closed with composite resin, teeth were restored with indirectly fabricated post-and-core foundations made from zirconia posts (Cerapost or Cosmopost) combined with heat-pressed ceramic cores (IPS Empress Cosmo) and ceramic crowns (IPS Empress II). Restorations (posts and crowns) were cemented with glass-ionomer cement (KetacCem) or resin-modified glass-ionomer cement (ProTec Cem) and reevaluated, retrospectively, for failures such as loss of retention or fractures. Data were reported using descriptive statistics. RESULTS: The mean observation period was 29 months (range 8-44 months). No loss of retention or fracture of any restoration was observed. CONCLUSION: Although this study involved a relatively short observation period, there were no signs of failure of conventionally cemented zirconia posts with ceramic crowns.