Randomized trial investigating zirconia electroplated telescopic retainers: quality of life outcomes

Double-crown-retained removable dentures: Types and clinical application

A 55-year-old man wearing maxillary and mandibular clasp-retained removable partial dentures (RPDs) sought improvement in retention, support, mastication efficiency, and esthetics. Three prosthodontic treatment options were provided to the patient, who selected maxillary and mandibular conical crown-retained removable partial dentures (CCRPDs) without strategic implants. Oral health-related quality of life (OHRQoL) and satisfaction of the patient were evaluated before treatment and 2 weeks and 1 year after inserting the CCRPDs. The patient reported better retention, support, stability, mastication efficiency, esthetics, and an improved OHRQoL after CCRPD placement than before treatment. These improvements were maintained after 1 year.

Telescopic Denture: A Treatment Option for Occlusal Rehabilitation in Partially Edentulous Patients

The rehabilitation of a patient with multiple edentulous spaces, a collapsed occlusal vertical dimension, and compromised abutment teeth is demanding. For treating such patients, various approaches have been put forth over the years, with dental implants having the best results. However, they cannot be used on all patients due to their high cost and surgical limitations. Therefore, removable dentures are still a popular option. Telescopic removable dentures rest on the natural teeth, preserving the alveolar bone while providing good stability and support for the denture. The treatment goal was to establish normal form, function, and aesthetics to uplift the psychological status and maintain occlusal harmony in the patient. In this case report, a 45-year-old female patient who presented with many missing posterior teeth and a collapse in her vertical dimension received full mouth rehabilitation. The patient requested a maxillary denture with no visible metal clasps when smiling. Consequently, a conventional mandibular removable partial denture (RPD) and a cobalt-chromium maxillary telescopic denture were selected as the appropriate treatments. The final restored occlusion and appearance met the patient's satisfaction.

Oral health-related quality of life (OHRQoL) after rehabilitation with removable partial dentures (RPDs): A systematic review and meta-analysis

OBJECTIVES

To summarise evidence on the change in oral health-related quality of life (OHRQoL) before and after rehabilitation with removable partial dentures (RPDs) amongst partially edentulous adults.

DATA

Studies assessing OHRQoL amongst patients aged ≥18 years, before and after rehabilitation with RPDs of any type and design, were included. The quality of included studies was evaluated using the Cochrane risk of bias tools. Meta-analysis was conducted using a random-effect model.

SOURCES

MEDLINE, EMBASE and CENTRAL, up to March 29, 2022.

STUDY SELECTION AND RESULTS

Thirteen studies were eligible and eight were included in the meta-analysis. The studies had moderate to serious risk of bias. There was a very low level of certainty that OHRQoL, as measured using OHIP-14, improved 3 months after RPDs were fitted (222 participants, MD: -12.0, 95% CI: -16.1, -7.9, p<0.001) and after 6 months (101 participants, MD: -10.5, 95% CI: -16.4, -4.6, p<0.001). At 12 months post-treatment, RPD rehabilitation did not result in statistically significant improvement in OHIP-14 scores (62 participants, MD: -12.7, 95% CI: -26.1, 0.6, p = 0.06). However, the assessment using OHIP-49 at 12 months showed significant improvement (87 participants, MD: -34.8, 95% CI: -41.9, -27.7, p<0.001), with low certainty of evidence.

CONCLUSIONS

Based on the limited evidence available, this review found that RPD rehabilitation appear to improve OHRQoL in the short term up to 6 months, with a very low level of certainty. The long-term effect of RPD treatment on OHRQoL after 12 months is inconclusive. There is currently insufficient evidence on the effect of RPD treatment on OHRQoL. This review highlights the need for more and better quality studies.

CLINICAL SIGNIFICANCE

Data on RPD outcomes are summarised, aiding clinicians in providing evidence-based patient-centred care that matches patients' needs and expectations. Recommendations for future research were also highlighted.

REGISTRATION

PROSPERO CRD42022328606.

Full Mouth Rehabilitation Using Telescopic Removable Prosthesis

A female, aged 55 years, was presented to the clinic concerned with her inability to function properly due to missing teeth and collapse of her vertical dimension. On examination, remaining tooth position of the upper arch was favorable for telescopic denture and remaining tooth position of the lower arch was favorable for removable prosthesis. The patient requested an aesthetic maxillary and mandibular denture with no visible metal clasps on smiling. Therefore, upper telescopic removable complete denture and lower chrome cobalt removable prostheses were suggested to the patient as conservative treatment to reestablish her occlusal vertical dimension and restore her aesthetics and function.

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

PURPOSE

This study investigated the retentive force of conical crowns combining zirconia primary and fiber-reinforced composite (FRC) secondary crowns and their changes due to aging.

METHODS

Zirconia primary crowns were produced with a convergence angle of 3°. Thirty-two secondary crowns were milled from FRC and divided into two groups (n = 16/group) based on the polishing method of the secondary crown inner surfaces: diamond paste (Group 1) and silicone points (Group 2). After fitting the secondary crowns with different fitting forces (F), loosening forces (L) were determined. Tests were repeated after an occlusal stop (OS) was added to the secondary crown and artificial aging (10,000 insertion/removal cycles). Data were compared using the Wilcoxon and Mann-Whitney U tests.

RESULTS

Crowns without an OS showed L/F ratios of 0.4586 (Group 1) and 0.4104 (Group 2). With an OS, maximum retention was not significantly affected by the polishing method and could be limited to L_max = 19.31±7.77 N (Group 1) and L_max = 16.12±5.92 N (Group 2).

CONCLUSIONS

These findings suggest that the combination of conical zirconia primary and FRC secondary crowns can obtain acceptable retentive forces that are not affected by aging if the inner surfaces are polished with diamond paste. OS generation could limit maximum retention, but should be adjusted if the target value of 10 N is not to be exceeded. With a change of the convergence angle to 4°, L/F values for crowns without an OS would be close to 1/3, which is considered ideal for conical crowns.

CLINICAL SIGNIFICANCE

The combination of zirconia primary crowns and FRC secondary crowns was found feasible to ensure the required retention for clinical use over a long time span. Furthermore, it offers an alternative to metal-based restorations while ensuring high levels of biocompatibility and esthetics.

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

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.

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

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 R PDs.

Telescopic Denture

Aim:

This article explains the concept of telescopic denture.

Procedure:

It describes the different types of telescopic attachment (or double crown), and provides an overview of the advantages and the disadvantages of this type of prosthodontic treatment.

Conclusion:

The indications and the clinical applications of telescopic denture are discussed.

Electroplated telescopic retainers with zirconia primary crowns: 3-year results from a randomized clinical trial

OBJECTIVE

The objective of the study was to investigate the clinical outcome for electroplated telescopic removable dental prostheses (E-RDPs) with zirconia primary crowns.

MATERIALS AND METHODS

Sixty E-RDPs, with primary crowns manufactured from either cobalt-chromium alloy or zirconia, were fabricated for 56 participants. Electroplating was used to produce gold copings directly on the telescopic primary crowns. These copings were bonded intra-orally to the prosthesis framework. After 36 months, prosthesis survival and number of complications were assessed. Statistical analysis was performed by the use of Kaplan-Meier modeling and the log-rank test.

RESULTS

Survival of the E-RDPs, 96.4% after 3 years, was identical in both groups. The need for aftercare was high but not significantly different: technical complications were observed for 37% and 42.9% of the prostheses for the zirconia and cobalt-chromium alloy primary crowns, respectively. Fracture of composite veneer was the most frequent complication (59.1%). The incidence of fractured abutment teeth, decementation, and endodontic problems was 7.9% in the zirconia group and 14% in the control group. The majority of abutment-level complications were treated restoratively. A significant difference was found for maximum probing depth at the abutment teeth: In the zirconia group, it decreased by 0.2 mm, whereas it increased by 0.8 mm in the control group (p = 0.04).

CONCLUSIONS

After 3 years of observation, survival of zirconia E-RDPs was favorable and comparable with that of established double-crown-retained prostheses. Further studies must clarify whether there are benefits of zirconia primary crowns for periodontal health.

CLINICAL RELEVANCE

Although these results encourage the use of zirconia primary crowns, more research is necessary to reduce the number of complications observed for secondary telescopic crowns, for example, failure of the veneer.