Long-term behavior of double crown retained dentures with metal and metal-free secondary crowns and frameworks made of Vectris© on all-ceramic primary crowns: a prospective, randomized clinical trial up to 14 years

Zahn, Thomas; Zahn, B; Janko, S.; Weigl, Paul; Gerhardt‐Szép, Susanne; Lauer, Hans–Christoph

doi:10.1007/s00784-015-1597-y

Cited by 16 publications

(7 citation statements)

References 47 publications

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“…The existing tension will decrease as long as the limits of elasticity are exceeded anywhere in the contact area, whereas elasticity is specific for any given material. The results correspond to the statement that the retention mechanism of electroformed secondary crowns is based on adhesion, not on the wedge effect [5]. baseline-100 p = 0.000* p = 0.000* 100-200 p = 0.000* p = 0.000* 200-300 p = 0.000* p = 0.000* 300-400 p = 0.000* p = 0.000* 400-500 p = 0.000* p = 0.000* 500-600 p = 0.000* p = 0.001* 600-700 p = 0.004* p = 0.045* 700-800 p = 0.002* p = 0.004* 800-900 p = 0.157 p = 0.063 The retention of telescopic crowns in which the secondary parts are electroplated is based on the combination of capillary gap and saliva [12,13].…”

Section: Discussionsupporting

confidence: 87%

“…A cylindrical structure known as a telescopic crown is often used for double crowns and is characterized by equivalent gingival and occlusal circumference; therefore, no taper is employed [4]. Double crown systems offer more advantages than other types of attachments such as cross-arch stabilization of the abutment teeth, axial loading of the teeth, good retention, longevity, and are therefore suitable for elderly people, giving them oral comfort and self-confidence [5,6]. Commonly, double crowns are made of metal alloys, precious and non-precious, making a homogenous or heterogeneous friction pair.…”

Section: Introductionmentioning

confidence: 99%

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Retention force of overdenture retained with telescopic crowns: A comparison of polyether ether ketone and zirconia ceramic telescopic crowns

et al. 2020

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Introduction/Objective. Recently, new materials for double crowns have been introduced, such as zirconia and polyether ether ketone (PEEK). However, some characteristics of these materials, such as retentive force and duration of ?settling in phase,? have not been investigated sufficiently. During the ?settling in phase,? telescopic overdenture has not yet achieved its definitive retention force, and it can be harmful for periodontal tissue if the value is above optimal for a long period of time. The objective was to measure the in vitro overall pull-off force of telescopic crowns where primary crowns were made from zirconia ceramics and a survey of the ?settling in phase? duration. Methods. Forty zirconia primary telescopic crowns were produced on prepared canine teeth. Twenty secondary crowns were of PEEK and other 20 of zirconia with electroplated gold copings. The pull-off force measurements were conducted utilizing a dynamometer until a constant value was obtained. Results. The specimens of the PEEK group showed higher initial retentive force values. Settling in phase was finished between 800 and 900 cycles of separation for both groups. Comparing the value of the pull-off force between individual different cycles, a statistically significant reduction was recorded up to the 800th cycle, while between the 800th and the 900th cycle there was no difference. Conclusions. The settling in phase was finished between 800 and 900 cycles of separation in both groups. Final retentive force values for both tested telescopic groups were in the optimal range which is 5?9 N per one telescopic crown.

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Section: Discussionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Retention force of overdenture retained with telescopic crowns: A comparison of polyether ether ketone and zirconia ceramic telescopic crowns

et al. 2020

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“…Fitting the FRC secondary crown to the primary crown is easier than that of zirconia secondary crown because the FRC does not require a sintering process and there is no error in the sintering process. To date, secondary crowns fabricated from FRC have been used in clinical studies, 3D finite element analyses, and breaking tests [22,28], but there have been no studies in which retentive force tests and repeated insertion/removal tests were performed. The adjustment parameters during milling of the secondary crown were determined through test processing in advance.…”

Section: Discussionmentioning

confidence: 99%

“…For example, double crowns made from the combination of a zirconia primary crown and an electroformed gold secondary crown have been widely fabricated, and their performance has been demonstrated in numerous clinical reports and studies [18][19][20][21]. Zahn et al performed a prospective long-term trial, with nonmetallic secondary crowns made of composite resin reinforced with glass fibers (fiber-reinforced composite, or FRC) [22], but the glass fiber and the matrix resin were sourced separately, and manual fabrication work using a conventional working model was needed. Compared to electroformed secondary crowns, the risk of damage was significantly higher for FRC secondary crowns.…”

Section: Introductionmentioning

confidence: 99%

Retentive force of telescopic crowns combining fiber-reinforced composite and zirconia

et al. 2022

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Purpose: This study investigated changes in the retentive force of telescopic crowns fabricated by combining a zirconia primary crown and a fiber-reinforced composite (FRC) secondary crown. Methods: Primary zirconia crowns were produced with a nominal convergence angle of 0°. Forty-eight secondary crowns were milled from FRC and divided into three study groups (n=16/group) based on milling parameters and post-milling adjustment. The offset parameter used for the final milling step of the inner crown surface was adjusted for a tight initial fit in Group 1 (milling offset: +10 µm, i.e., 2 × 10 µm = 20 µm lower inner diameter compared with the CAD file of the crown) and for improved initial fit (milling offset: -10 µm, i.e., an enlargement of the inner crown diameter by 2 × 20 µm = 40 µm in relation to Group 1) in Groups 2 and 3. The inner surfaces of the secondary crowns were polished with diamond paste in Groups 1 and 2, and silicon points were used for Group 3. The retentive force was measured using a universal testing device. The secondary crown was placed on the primary crown, with the final fitting force set to a load of 100 N. This test was conducted before and after aging (10,000 insertion/removal cycles) under dry and wet conditions. A generalized linear model was used to estimate the differences in the retentive force to elucidate the effects of the milling parameters and polishing methods. Results: We realized an initial retentive force of approximately 10 N. In Groups 2 and 3, the difference was statistically significant between the dry and wet conditions before aging (P < 0.05). There was no significant difference between the dry and wet conditions after aging in any of the groups (P > 0.05). Conclusions: An adequate initial retentive force can be achieved with telescopic crowns combining zirconia and FRC.

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“…An RCT exhibited a favorable and comparable survival rate of a zirconia primary crown, compared to those of Co-Cr primary crowns [36]. Another RCT revealed that double-crown-retained RPDs with glass ceramic or glass fiber-reinforced composite material crowns have insufficient strength, resulting in a high fracture rate [59]. Therefore, when choosing ceramic materials for the fabrication of double-crownretained RPDs, high-strength zirconia ceramics should be recommended for the long-term use of a prosthesis.…”

Section: Double-crown-retained Rpdsmentioning

confidence: 99%

A systematic review of digital removable partial dentures. Part I: Clinical evidence, digital impression, and maxillomandibular relationship record

et al. 2022

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Purpose: This study comprehensively reviewed the current status of digital workflows in fabricating removable partial dentures (RPDs) using evidence from clinical trials and case reports. Study selection: We performed a systematic review of the literature on the materials and fabrication of RPDs using digital technologies published in online databases from 1980 to 2020. We selected eligible articles from the search results, retrieved information on digital RPDs from these, and conducted a qualitative analysis. We report evidence from clinical papers and case reports, digital impression-taking methods, and maxillomandibular relationship (MMR) records. Results: A case report electronically published in 2019 introduced a clasp-retained RPD fabricated via a full-digital workflow without a gypsum definitive cast. Computer-aided design and computer-aided manufacturing of double-crown-retained RPDs with nonmetal materials were described in some case reports. Intraoral scanners were used to obtain digital impressions and MMR records in the fabrication of digital RPDs, which have potential advantages for reducing the number of clinical appointments and simplifying laboratory procedures. Evidence from clinical trials is scarce; a randomized controlled trial reported higher patient satisfaction with digital clasp-retained RPDs than with conventional RPDs. Conclusions: Full-digital RPDs can be fabricated without a gypsum definitive cast. However, the indication for full-digital RPDs is limited to cases with Kennedy Class III/IV partially edentulous arches with several missing teeth. Challenges in digital impression-taking and MMR recording remain to be solved to extend these indications. More evidence from clinical trials is required to evaluate the efficacy and usefulness of digital RPDs.

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Long-term behavior of double crown retained dentures with metal and metal-free secondary crowns and frameworks made of Vectris© on all-ceramic primary crowns: a prospective, randomized clinical trial up to 14 years

Abstract: Both clinical and statistical data indicated the superiority of the restorations made with electroplated secondary crowns and metal framework. Therefore, the use of Vectris(©) cannot be recommended for the fabrication of double crown retained removable dentures as permanent restorations.

Cited by 16 publications

References 47 publications

Retention force of overdenture retained with telescopic crowns: A comparison of polyether ether ketone and zirconia ceramic telescopic crowns

Retention force of overdenture retained with telescopic crowns: A comparison of polyether ether ketone and zirconia ceramic telescopic crowns

Retentive force of telescopic crowns combining fiber-reinforced composite and zirconia

A systematic review of digital removable partial dentures. Part I: Clinical evidence, digital impression, and maxillomandibular relationship record

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