A randomised controlled trial of two-unit cantilevered or three-unit fixed-movable resin-bonded fixed partial dentures replacing missing molars

Zirconia single retainer fixed dental prostheses for the posterior region-A novel preparation technique and literature review

The principles of tissue preservation, minimally invasiveness and approaching different clinical situations biologically rather than surgically govern today's dentistry. Thus, different clinical scenarios require procedures that offer the dentist and the patient the possibility to choose the more invasive treatment options later in life. Subsequently, the case reported refers to a minimally invasive technique that treats single tooth edentulism using single partial retainer FDPs fabricated from monolithic zirconia. This approach is conservative, biocompatible, aesthetic, strong, rapidly obtained through CAD/CAM techniques and cost-effective.

Aesthetical and Functional Rehabilitation for an Ankylosed Maxillary Canine-A Case Report

Background: As the functional and aesthetical importance of the canine cannot be overstated, the management of a missing canine is challenging. This case report describes the treatment of an infra-occluded ankylosed maxillary canine in a patient with previously failed orthodontic treatment. Case description: A 20-year-old patient sought a second opinion for orthodontic treatment failure. The patient presented with an impacted, ankylosed, and severely infra-occluded right maxillary canine, as well as an iatrogenic clockwise cant of the maxillary occlusal plane and several root resorptions. The treatment corrected the cant of the occlusal plane while avoiding further root resorption, partially extracted the upper right canine, improved the quality and quantity of the soft tissue in the newly edentulous area, and provided a prosthetic rehabilitation using a lithium disilicate ceramic resin-bonded cantilever bridge. Conclusions: The use of a cantilevered bridge resulted in an aesthetically pleasing and minimally invasive rehabilitation. This technique is reversible, does not affect pulp vitality, and is a viable solution for rehabilitating the smiles of young patients. Clinical significance: The smile rehabilitation for an ankylosed maxillary canine, especially in the case of a previously failed orthodontic treatment, is an important clinical challenge. A minimally invasive long-term restoration with a cantilever bridge is a viable solution. Functional and aesthetically pleasant results can be achieved with a multidisciplinary approach.

Posterior two-unit cantilevered zirconia resin-bonded fixed partial dentures: A 3-year prospective single-arm clinical trial

OBJECTIVES

To evaluate the longevity of cantilevered zirconia-based resin-bonded fixed partial dentures (RBFPDs) in replacing missing posterior teeth, as well as the quality of life and patient satisfaction experienced by those receiving zirconia RBFPDs.

METHODS

A prospective single-arm uncontrolled clinical trial was conducted to replace one or more missing premolars or molars with a span of 5 to 8 mm using cantilevered zirconia RBFPDs. Thirty-six participants with 40 prostheses were recruited and underwent a 3-year clinical evaluation. The retainer designs included a minimum thickness of 0.8 mm, a minimum of 200° circumferential wraparound with an occlusal bar, and a connector dimension of 3 × 3 mm. Patient-reported outcomes, including patient satisfaction and Oral Health Impact Profile (OHIP), were assessed.

RESULTS

The average age of participants was 45.8 years, and 72.5 % were women. The success rate of the posterior zirconia RBFPDs was 76.2 %, with an estimated mean success duration of 46.1 months. The survival rate was 88.1 %, with an estimated mean survival duration of 49.4 months. Participants were highly satisfied with the treatment, achieving an average satisfaction score of 80.8 ± 11.9. Participants' total OHIP scores decreased from 52.3 to 39.6 after 3 years, indicating a significant improvement in oral health-related quality of life (P = 0.009).

CONCLUSIONS

After 3 years, a moderately high survival rate and favourable patient-reported outcomes of posterior cantilevered zirconia RBFPDs were achieved. Therefore, it can be recommended as a conservative treatment option to replace missing posterior teeth, provided that retainer design considerations are taken into account.

CLINICAL SIGNIFICANCE

Cantilevered zirconia RBFPDs for posterior teeth can serve as a conservative treatment option that is both aesthetically pleasing and biocompatible. It offers a more cost-effective alternative compared to dental implants, which are often prohibitively expensive for the majority of patients. This approach has the potential to greatly improve patient-reported outcomes.

Outcome measurements and quality of randomized controlled clinical trials of tooth-supported fixed dental prostheses: A systematic review and qualitative analysis

STATEMENT OF PROBLEM

The lack of consensus regarding a standardized set of outcome measurements and noncompliance with current reporting guidelines in clinical trials of tooth-supported fixed dental prostheses (FDPs) hamper interstudy comparability, compromise scientific evidence, and waste research effort and resources in prosthetic dentistry.

PURPOSE

The primary objective of this systematic review was to identify all primary and secondary outcome measurements assessed in randomized controlled trials (RCTs) of tooth-supported FDPs. Secondary objectives were to assess their methodological quality by using the Cochrane Collaboration's risk of bias tool (RoB, v2.0) and their reporting quality by means of a standardized 16-item CONSORT assessment tool through published reports.

MATERIAL AND METHODS

An electronic search was conducted in MEDLINE, EMBASE, and Cochrane library to identify all RCT-related articles published in the past 10 years. Differences in RoB were tested with the Pearson chi-squared test, and those in CONSORT score with the Student t test.

RESULTS

A total of 64 RCTs from 79 publications were deemed eligible. The diversity of outcome measures used in the field is apparent. Twenty percent of the included studies had a low RoB, 79% showed some concerns, and 1% had a high RoB. The mean ±standard deviation CONSORT compliance score was 22.56 ±3.17. Trials adhered to the CONSORT statement reported lower RoB than those that did not adhere (P<.001). RCTs with a low RoB reported more comprehensive adherence to CONSORT guidelines than those with some concerns (MD 4 [95% CI 1.52-6.48]; P=.004).

CONCLUSIONS

A standardized core outcome reporting set in clinical research on tooth-supported FDPs remains evident. Adherence to the CONSORT statement continues to be low, with some RoB concerns that can be improved.

Long-term clinical outcome of three-unit fixed-fixed posterior zirconia ceramic inlay-retained FDPs with a modified design

OBJECTIVES

To assess the long-term clinical outcome of posterior inlay-retained fixed dental prostheses (IRFDPs) with a modified design made from zirconia ceramic.

METHODS

In 30 patients thirty 3-unit IRFDPs were placed to replace 7 premolars (4 in the maxilla, 3 in the mandible), and 23 first molars (15 in the maxilla, 8 in the mandible). Preparations were accomplished in agreement with the general principles for ceramic inlay restorations and modified with a short retainer-wing bevel preparation within the enamel at the buccal and oral sides. The frameworks were milled from 3Y-TZP ceramic, and the pontics were veneered with feldspathic ceramic. All IRFDPs were bonded with a phosphate monomer containing luting resin after air-abrasion of the intaglio surfaces. The patients were recalled 6-12 months after placement, and then annually. Kaplan-Meier analysis was used to calculate the survival and complication rates of the IRFDPs.

RESULTS

The mean observation time was 10.6 ± 1.5 years. The 10-year cumulative survival rate was 89% with 4 failures, two of them were due to deep secondary caries with loss of retention, one due to repeated debonding with enamel fractures, and one due to generalized progressive periodontitis. The most common complication was chipping of the veneering ceramic (20.1%). Eighteen IRFDPs were free of any type of complication up to 15.4 years, which corresponds to a 10-year cumulative success rate of 70.4%.

CONCLUSION

The long-term clinical performance of modified IRFDPs made of veneered zirconia ceramics was favorable after 10 years, therefore, they represent a treatment alternative to replace posterior single missing teeth.

CLINICAL SIGNIFICANCE

Zirconia-based IRFDPs fabricated in the modified design may represent a substance-preserving alternative to conventional posterior FDPs to replace posterior single missing teeth, particularly in cases where implants cannot be placed, and when the adjacent teeth already have small restorations or defects.

Chairside posterior cantilevered fixed partial denture: Case report

The cantilevered fixed partial denture (CFPD) is gaining recognition as a sound method of replacing missing teeth in the posterior sector. The purpose of this case report is to demonstrate that this type of restoration can be performed in a single appointment. A 39-year-old patient presented herself to the dental department; she showed agenesis of the two first maxillary premolars with a totally closed mesio-distal gap and a recent loss of the 2 s maxillary premolars. This case report concerns the replacement of the upper left second premolar. The patient was treated with a mesial CFPD resting on an "onlay-like" retainer on the first molar and replacing the missing premolar with a cantilevered pontic. The dimensions of the connection's cross-section were maximized as much as possible (>20 mm2). The restoration was designed and produced using chairside CAD-CAM from a milled-reinforced glass-ceramic block (Emax CAD, Ivoclar Vivadent). The aesthetic and functional integration of the prosthesis was successful. The patient was examined at 11 months for a follow-up. At this early stage, satisfactory dental hygiene was observed, associated with a smooth prosthetic fit, no periodontal inflammation, normal probing, and no abnormal dental mobility.

Evaluation of different designs for posterior cantilever zirconia inlay-retained fixed dental prostheses in missing tooth replacement: Stage one results with 18-month follow-up assessment

OBJECTIVES

This clinical study aimed to investigate the outcomes and survival rates of different variations of inlay-retained fixed dental prostheses (IR-FDPs) composed of monolithic zirconia ceramic. The IR-FDPs with a single-retainer design were used for replacing missing mandibular second premolars. The research evaluated the effectiveness and longevity of these prostheses in clinical settings.

METHODS

A total of 30 IR-FDPs (n = 30) were placed for 27 female patients who presented with missing mandibular second premolar teeth. For this study, the mandibular first molar was chosen as a retainer for the cantilever IR-FDPs and the study involved a random assignment of participants into three distinct groups, each comprising 10 individuals (n = 10). The criterion for the grouping was the retainer design: inlay ring (IR), lingual coverage (LC), and occlusal coverage (OC). The three groups included mesial inlay box with the same dimensions (3 mm height, 3 mm width and 2 mm depth). All IR-FDPs were manufactured using monolithic high translucent 3Y zirconia and the connector area to the cantilever pontic was adjusted to dimensions of 3 × 3 mm for all designs. The restorations were bonded using adhesive resin cement. The clinical and radiographic evaluations of the restorations were conducted for a duration of 18 months, following the modified FDI (World Dental Federation) criteria.

RESULTS

The restorations were observed in stage one for a period of 18 months. Only one restoration in group LC was debonded after 10 months and re-bonded. The clinical quality of all crowns and the patient's satisfaction were high. No adverse soft tissue reactions around the crowns were observed and only one abutment in group IR was endodontically treated after 12 months.

CONCLUSIONS

Zirconia cantilever IR-FDPs offer a viable short-term treatment option for replacing missing posterior teeth, providing esthetic and functional benefits while minimizing invasiveness. Over an 18-month observation period, these prostheses have demonstrated a remarkable survival rate of 100% and a success rate of 96.6%. These findings suggest the effectiveness and reliability of zirconia cantilever IR-FDPs as a short-term solution for replacing missing posterior teeth.

CLINICAL SIGNIFICANCE

Zirconia cantilever IR-FDPs could present a practical solution for addressing posterior tooth loss, especially in cases where implant placement is not recommended and conventional fixed dental prostheses entail excessive invasiveness.

Retention durability of one-retainer versus two-retainer posterior RBFDPs after chewing simulation

The clinical use of one-retainer RBFDPs in the anterior region has shown higher survival rates compared to conventional two-retainer RBFDPs. The motivation for this study was to assess the validity of this observation when extended to the posterior region. The aim was thus to evaluate different preparation and framework designs for replacing premolars, particularly one-retainer versus two-retainer designs, on the retention of monolithic zirconia posterior RBFDPs. Extracted caries-free human premolars and third molars were embedded in auto-curing resin to create models with an edentulous space of premolar width. Abutment teeth were prepared according to these six designs (n = 8 each): one or two upper retainers with narrow rests, one or two upper retainers with wide rests, and one or two-retainers with wide rests. RBFDPs were milled from monolithic zirconia (KATANA Zirconia HT), and were adhesively bonded using Panavia V5 with corresponding primers. After thermodynamic loading, the quasi-static tensile force required for failure was determined. Failure modes were evaluated using a microscope. Survival rates after thermodynamic loading were 75% for one group (one upper-molar retainer with narrow rest), 100% for the other groups. The debonding forces ranged from 310 ± 224 N (group one upper-molar retainer with narrow rest) to 927 ± 292 N (group two upper retainers with narrow rests). Two-retainer designs failed at significantly higher tensile forces than designs with one retainer (p ≤ 0.05). There were no significant differences between upper and lower designs, or rest widths. Although RBFDPs with two retainers withstood higher debonding forces, RBFDPs with one retainer and wide rest still have a high potential for clinical treatment because of the high forces required for their debonding.

Comparison of Tensile Bond Strength of Fixed-Fixed Versus Cantilever Single- and Double-Abutted Resin-Bonded Bridges Dental Prosthesis

Resin-bonded fixed dental prostheses (RBFDP) are minimally invasive alternatives to traditional full-coverage fixed partial dentures as they rely on resin cements for retention. This study compared and evaluated the tensile bond strength of three different resin-bonded bridge designs, namely, three-unit fixed-fixed, two-unit cantilever single abutment, and three-unit cantilever double-abutted resin-bonded bridge. Furthermore, the study attempted to compare the tensile bond strengths of the Maryland and Rochette types of resin-bonded bridges. Based on the inclusion and exclusion criteria, a total of seventy-five extracted maxillary incisors were collected and later were mounted on the acrylic blocks. Three distinct resin-bonded metal frameworks were designed: three-unit fixed-fixed (n = 30), two-unit cantilever single abutment (n = 30), and a three-unit cantilever double abutment (n = 30). The main groups were further divided into two subgroups based on the retainer design such as Rochette and Maryland. The different prosthesis designs were cemented to the prepared teeth. Later, abutment preparations were made on all specimens keeping the preparation as minimally invasive and esthetic oriented. Impression of the preparations were made using polyvinyl siloxane impression material, followed by pouring cast using die stone. A U-shaped handle of 1.5 mm diameter sprue wax with a 3 mm hole in between was attached to the occlusal surface of each pattern. The wax patterns were sprued and cast in a cobalt-chromium alloy. The castings were cleaned by sandblasting, followed by finishing and polishing. Lastly, based on the study group, specimens for Rochette bridge were perforated to provide mechanical retention between resin cement and metal, whereas the remaining 15 specimens were sandblasted on the palatal side to provide mechanical retention (Maryland bridge). In order to evaluate the tensile bond strength, the specimens were subjected to tensile forces on a universal testing machine with a uniform crosshead speed. The fixed-fixed partial prosthesis proved superior to both cantilever designs, whereas the single abutment cantilever design showed the lowest tensile bond strength. Maryland bridges uniformly showed higher bond strengths across all framework designs. Within the limitations of this study, the three-unit fixed-fixed design and Maryland bridges had greater bond strengths, implying that they may demonstrate lower clinical failure than cantilever designs and Rochette bridges.

Clinical evaluation of zirconia cantilevered single-retainer resin-bonded fixed dental prostheses replacing missing canines and posterior teeth

OBJECTIVES

This clinical study evaluated the outcome and survival rate of resin-bonded fixed dental prostheses (RBFDPs) made of 3Y-TZP zirconia ceramic with a single-retainer design in the replacement of missing canines, premolars and molars.

METHODS

Twenty-one patients that were provided with twenty-seven cantilevered zirconia ceramic RBFDPs replacing maxillary or mandibular missing canines or posterior teeth were recruited from the patients' database at the University of Kiel, Germany. The preparation of the abutment teeth was minimal and limited to the enamel and consisted of a retainer wing and an occlusal rest on the abutment tooth. The restorations were observed over up to 12 years.

RESULTS

The patient age ranged from 16 to 72 years old with a mean age of 34 ± 21 years and 57% were females and 43% were males. The restorations were observed for a mean period of 53 ± 39 months with a minimum of 13 months and a maximum of 151 months of observation. No debonding for any of the restorations was detected, which amounts up to a survival rate of 100%. The development of treatable cervical caries on one abutment tooth of an elderly patient without extending to the retainer wing was the only recorded complication.

CONCLUSIONS

Zirconia ceramic single-retainer RBFDPs provide an esthetic, functional and minimally invasive treatment alternative to replace missing canines, premolar and molars with promising results due to excellent clinical outcome resulting from a survival rate of 100% and a success rate of 96.3% over a mean observation time of 53 ± 39 months.

CLINICAL SIGNIFICANCE

Zirconia ceramic single-retainer RBFDPs might be a valid minimally-invasive option for replacing missing canines and missing teeth in the posterior area especially for young patients, in whom implants are contraindicated and conventional fixed dental prostheses are too invasive.