Effects of denture adhesive on the retention of milled and heat-activated maxillary denture bases: A clinical study

Which clinical and laboratory procedures should be used to fabricate digital complete dentures? A systematic review

STATEMENT OF PROBLEM

Digital workflows for digital complete denture fabrication have a variety of clinical and laboratory procedures, but their outcomes and associated complications are currently unknown.

PURPOSE

The purpose of this systematic review was to evaluate the clinical and laboratory procedures for digital complete dentures, their outcomes, and associated complications.

MATERIAL AND METHODS

Electronic literature searches were conducted on PubMed/Medline, Embase, and Web of Science for studies published from January 2000 to September 2022 and screened by 2 independent reviewers. Information on digital complete denture procedures, materials, their outcomes, and associated complications was extracted.

RESULTS

Of 266 screened studies, 39 studies were included. While 26 assessed definitive complete dentures, 7 studies assessed denture bases, 2 assessed trial dentures, and 4 assessed the digital images only. Twenty-four studies used border molded impression technique, 3 studies used a facebow record, and 7 studies used gothic arch tracing. Only 13 studies performed trial denture placement. Twenty-one studies used milling, and 17 studies used 3D printing for denture fabrication. One study reported that the retention of maxillary denture bases fabricated from a border-molded impression (14.5 to 16.1 N) was statistically higher than the retention of those fabricated from intraoral scanning (6.2 to 6.6 N). The maximum occlusal force of digital complete denture wearers was similar across different fabrication procedures. When compared with the conventional workflow, digital complete dentures required statistically shorter clinical time with 205 to 233 minutes saved. Up to 37.5% of participants reported loss of retention and up to 31.3% required a denture remake. In general, ≥1 extra visit and 1 to 4 unscheduled follow-up visits were needed. The outcomes for patient satisfaction and oral health-related quality of life were similar between conventional, milled, and 3D printed complete dentures.

CONCLUSIONS

Making a border-molded impression is still preferred for better retention, and trial denture placement is still recommended to optimize the fabrication of definitive digital complete dentures.

Clinical performance and patient-related outcome measures of digitally fabricated complete dentures: A systematic review and meta-analysis

STATEMENT OF PROBLEM

The demand to streamline workflow while increasing patient comfort and satisfaction in the manufacturing of removable complete dentures (CDs) is growing, and computer-aided design and computer-aided manufacturing (CAD-CAM) technology has gained prominence. However, a systematic review and meta-analysis of the clinical performance and patient-related outcome measures (PROMs) of digitally fabricated complete dentures is lacking.

PURPOSE

The purpose of this systematic review and meta-analysis was to determine whether digitally fabricated CDs improve the clinical performance and PROMs compared with conventionally fabricated CDs.

MATERIAL AND METHODS

This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and was registered at the International Prospective Register of Systematic Reviews (CRD42023433909). This review aimed to address the question "Do digitally fabricated CDs improve clinical performance and PROMs compared with conventional CDs?" Two independent authors conducted electronic searches up to September 2023. Denture base retention and patient satisfaction were analyzed through the continuous outcome evaluated by mean difference and standard deviation, with 95% confidence intervals. The risk of bias in each study was assessed using the Risk of Bias In Non-randomized Studies of Interventions and the Risk of Bias based on the Cochrane risk of bias tool for randomized trials. The certainty of evidence was assessed using Grading of Recommendations, Assessment, Development and Evaluation.

RESULTS

A total of 1505 articles were found during the search, and 16 were included in this review. The main outcomes were grouped into clinical performance (retention, adaptation or fit, clinician's denture quality assessment, masticatory efficiency, and occlusal force) and PROMs (patient satisfaction, oral health related quality of life, final choice, and willingness-to-pay). In terms of denture base retention, between conventional CDs and printed CDs analyses, conventional CDs exhibited better retention (P=.02), but no significant difference was found between the conventional CDs and milled CDs (P=.20). In terms of patient satisfaction, no statistically significant difference was found between the manufacturing methods of digitally fabricated CDs (printed CD, P=.55; milled CD, P=.08).

CONCLUSIONS

Digitally fabricated CDs showed similar or better clinical performance than conventional CDs, and different types of digital manufacturing processes for complete dentures did not influence PROMs.

Clinical outcomes of milled, 3D-printed, and conventional complete dentures in edentulous patients: A systematic review and meta-analysis

PURPOSE

This systematic review aims to compare clinical outcomes of digital dentures with conventional dentures.

MATERIALS AND METHODS

This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered in Prospero. The formulated population, intervention, comparison, outcome (PICO) question was "What is the clinical outcome of digital versus conventional complete dentures (CDs) in edentulous patients?". The search strategy used three main electronic databases and an additional manual search was completed in August 2023 by following an established search strategy. Initial inclusion was based on titles and abstracts, followed by a detailed review of selected studies, and clinical studies that evaluated the clinical outcome of digital (milled or 3D-printed) versus conventional CDs were included. A qualitative analysis for clinical studies was used to assess the risk of bias. The certainty of the evidence was assessed according to the grading of recommendations, assessment, development, and evaluations (GRADE) system. In addition, a single-arm meta-analysis was performed to evaluate the retention between digital versus conventional CDs.

RESULTS

The initial search yielded a total of 947 articles, out of which 19 were selected for a comprehensive review, and six met the eligibility criteria to be included in this systematic review. The computer-aided design and computer-aided manufacturing (CAD-CAM) CDs showed increased retention, no relevant differences in oral health-related quality of life (OHRQoL), and shorter working time compared to conventional dentures. Two studies were eligible for meta-analysis; retention was significantly better among CAD-CAM fabricated dentures (standardized mean difference [SMD] 0.501) than conventional dentures. The heterogeneity between studies was high (95% CI: 0.049-0.952).

CONCLUSIONS

Clinically, both the milled and the 3D-printed CD fared better than conventional dentures in terms of retention, reduction in the number of appointments, improved patient comfort, and improved predictable maintenance of the denture. Patients' perceptions and satisfaction were independent of the digital and conventional fabricated dentures.

Fit and retention of complete denture bases: Part I - Conventional versus CAD-CAM methods: A clinical controlled crossover study

STATEMENT OF PROBLEM

Clinical evidence is sparse on whether dentures fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM) methods afford superior fit and retention when compared with those fabricated conventionally.

PURPOSE

The purpose of this clinical controlled crossover study was to evaluate the peak retention force and fit of CAD-CAM manufactured (3D printed and milled) maxillary complete denture bases and conventional heat-polymerized bases (control).

MATERIAL AND METHODS

Twenty participants with edentulous maxillary arches were recruited. Impressions were made with a border-molded custom tray, and the resulting definitive cast was scanned. The conventional base was manufactured on the definitive cast with a hook and a 45-degree platform with a central notch and 2 lateral notches. The scan of the definitive cast was used for the fabrication of a milled and a printed base. The platform and hook position on the conventional base were transferred digitally to the milled and printed bases. All bases were scanned. A traction dynamometer was orientated into the notches, and retention was evaluated in the post dam and tuberosity areas. Scans were imported into a comparison software program which matched scans to their corresponding reference and performed a 3-dimensional comparison. The Friedman and Wilcoxon tests were used to compare between groups (confidence interval: 95%, α=.05).

RESULTS

Nineteen participants with a mean ±standard deviation age of 64.1 ±14.7 years completed all clinical sessions. No significant difference in peak retention was measured between milled (MB1), printed (PB1), and conventional (CB) bases in the post dam (CB: 12.44 ±9.62 N, PB1: 16.08 ±15.28 N, MB1: 14.52 ±17.07 N) and right tuberosity area (CB: 8.99 ±7.82 N, PB1: 11.28 ±9.57 N, MB1: 11.99 ±12.10 N). In the left tuberosity area, peak retention was lower for CB (10.03 ±8.39 N) than PB1 (14.98 ±14.72 N) and MB1 (13.55 ±15.53 N; P=.05). Compared with the definitive cast, the fit of the conventional base (0.18 ±0.01 mm) was closer than the printed (0.21 ±0.03 mm) and milled bases (0.21 ±0.02 mm) (P<.001).

CONCLUSIONS

The CD bases manufactured by CAD-CAM techniques provided retention and fit similar to that of conventionally manufactured bases and can therefore be considered suitable techniques.

Comparative Evaluation of the Digital Workflow and Conventional Method in Manufacturing Complete Removal Prostheses

The aging population in developed countries has increased the number of edentulous patients and, therefore, the need for prosthetic rehabilitation to improve their quality of life. Complete dentures are the main treatment option in these cases. The use of CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) in dentistry has improved clinical protocols and outcomes, achieving a reduction in work time and economic costs for the patients. The main objective of this review was to compare the characteristics of conventional and digital dentures, attempting to determine whether the use of new technologies represents an improvement in the properties of removable complete dentures. A bibliographic review was carried out in the PubMed/MEDLINE, Cochrane Library, Scielo, and Embase databases. With the initial search, 157 articles were obtained. After applying the inclusion and exclusion criteria, 64 publications were selected for this bibliographic review. The different conclusions of the studies consulted were compared regarding fit and retention, fracture resistance, surface roughness, biocompatibility, and aesthetics, taking into account the different methods of prostheses fabrication. In general, digital prostheses have shown better mechanical properties and, consequently, better biocompatibility and aesthetics than conventional prostheses. However, the obtained results were very heterogeneous, preventing a supported conclusion.

Influence of different denture adhesives on patient-based outcomes: A crossover randomized controlled trial

STATEMENT OF PROBLEM

The influence of different denture adhesive forms on retention, stability, denture movement, and masticatory efficiency have been studied. However, studies that investigated their effect on patient-based outcomes are scarce.

PURPOSE

The purpose of this crossover randomized controlled trial was to investigate the influence of 3 different denture adhesive forms on patient satisfaction and oral health-related quality of life (OHRQoL) in edentulous individuals.

MATERIAL AND METHODS

A total of 30 edentulous participants were enrolled. They initially received conventional dentures, which they used for 3 months. They were then instructed to use 3 forms of denture adhesives (cushion, paste, and powder) for 3 months each. Patient satisfaction was assessed by using a visual analog scale (VAS), and OHRQoL was assessed by using the oral health impact profile in the edentulous adults instrument. Assessments were done 3 months after wearing the conventional dentures, then after by using each denture adhesive form for 3 months, with a 1-month washout period. The average retention duration for each form and participant preference were also evaluated. Statistical analysis was conducted by using the repeated measures ANOVA test followed by the Scheffé test for VAS scores and retention duration. The Friedman test followed by the Wilcoxon signed-rank test was used for OHRQoL scores (α=.05).

RESULTS

Irrespective of their forms, denture adhesives significantly improved patient satisfaction in most aspects (P<.001) and significantly improved OHRQoL (P<.001). VAS scores for the cushion form were significantly higher than those for the other 2 forms regarding general satisfaction, comfort, and ease of cleaning dentures and tissues. For stability and masticatory ability, the cushion and paste forms were significantly better (P<.05) than the powder form. OHRQoL scores were significantly higher (worse) for the powder form compared with the other 2 forms for the functional limitation, physical pain, and physical disability domains, with insignificant differences between the cushion and paste forms (P>.05). The powder form found the shortest retention duration and the least preference.

CONCLUSIONS

Denture adhesives significantly improved OHRQoL and almost all aspects of patient satisfaction. The cushion form provided higher satisfaction levels for most aspects, followed by paste and then powder. OHRQoL outcomes were comparable for all forms, except for the functional limitation, physical pain, and physical disability domains, which were significantly better with the cushion and paste forms. The cushion and paste forms were more retentive and more preferred by the participants than the powder form.

Influence of postpolymerization time and atmosphere on the mechanical properties, degree of conversion, and cytotoxicity of denture bases produced by digital light processing

STATEMENT OF PROBLEM

Studies on the effects of postprocessing conditions on the physical properties, degree of conversion (DC), and biocompatibility of denture bases produced by digital light processing are lacking.

PURPOSE

The purpose of this in vitro study was to evaluate the effects of the atmosphere during postpolymerization and of postpolymerization time on the flexural strength, Vickers hardness, DC, cytotoxicity, and residual monomer content of denture bases.

MATERIAL AND METHODS

Six different groups of bar- and disk-shaped specimens from the denture base resin were produced, considering 2 different atmospheres (air and nitrogen) and 3 different postpolymerization times (5, 10, and 20 minutes). To determine the physical properties, the flexural strength and Vickers hardness were measured. Fourier transform infrared spectrometry was used to calculate DC. Cytotoxicity was assessed from the effect on human gingival fibroblasts. The residual monomer content was determined by using high-performance liquid chromatography. Based on the normality test by the Shapiro-Wilk method, a nonparametric factorial analysis of variances was conducted (α=.05).

RESULTS

A significant interaction was detected between the atmosphere and postpolymerization time for hardness (P<.001) but no interaction for strength, DC, or cytotoxicity (P=.826, P=.786, and P=.563, respectively). Hardness was significantly affected by the postpolymerization time in the groups with the nitrogen atmosphere (P<.001). DC was significantly affected by the atmosphere (P=.012), whereas strength and cytotoxicity were not (P=.500 and P=.299, respectively). Cytotoxicity was significantly affected by the postpolymerization time (P<.001), but strength and DC were not (P=.482 and P=.167, respectively). Residual monomers were not detected after ≥10-minute postpolymerization time.

CONCLUSIONS

The atmosphere significantly affected hardness and DC, whereas the postpolymerization time significantly affected hardness, DC, cytotoxicity, and residual monomer content. Denture bases produced in a nitrogen atmosphere and with the 10-minute postpolymerization time showed sufficient hardness, DC, and no cytotoxicity.

CAD-CAM removable complete dentures: A systematic review and meta-analysis of trueness of fit, biocompatibility, mechanical properties, surface characteristics, color stability, time-cost analysis, clinical and patient-reported outcomes

OBJECTIVES

This review compared Computer-aided designand Computer-aided manufactured (CAD-CAM) and conventionally constructed removable complete dentures (CDs).

DATA

Seventy-three studies reporting on CAD-CAM (milled/3D-printed) CDs were included in this review. The most recent literature search was performed on 15/03/2021.

SOURCES

Two investigators searched electronic databases [PubMed (MEDLINE), Embase, CENTRAL], online search engines (Google) and research portals. Hand searches were performed to identify literature not available online.

STUDY SELECTION

Studies on CAD-CAM CDs were included if they reported on trueness of fit, biocompatibility, mechanical, surface, chemical, color , microbiological properties, time-cost analysis, and clinical outcomes. Inter-investigator reliability was assessed using kappa scores. Meta-analyses were performed on the extracted data .

RESULTS

The kappa score ranged between 0.897-1.000. Meta-analyses revealed that 3D-printed CDs were more true than conventional CDs (p = 0.039). Milled CDs had a higher flexural-strength than conventional and 3D-printed CDs (p < 0.0001). Milled CDs had a higher flexural-modulus than 3D-printed CDs (p < 0.0001). Milled CDs had a higher yield-strength than injection-molded (p = 0.004), and 3D-printed CDs (p = 0.001). Milled CDs had superior toughness (p < 0.0001) and surface roughness characteristics (p < 0.0001) than other CDs . Rapidly-prototyped CDs displayed poor color-stability compared to other CDs (p = 0.029). CAD-CAM CDs d displayed better retention than conventional CDs (p = 0.015). Conventional CDs had a higher strain at yield point than milled CDs (p < 0.0001), and had superior esthetics than 3D-printed (p < 0.0001). Fabrication of CAD-CAM CDs required less chairside time (p = 0.037) and lower overall costs (p < 0.0001) than conventional CDs.

CONCLUSIONS

This systematic review concludes that CAD-CAM CDs offer a number of improved mechanical/surface properties and are not inferior when compared to conventional CDs.

CLINICAL SIGNIFICANCE

CAD-CAM CDs should be considered for completely edentulous patients whenever possible, since this technique offers numerous advantages including better retention, mechanical and surface properties but most importantly preserves a digital record. This can be a great advantage for older adults with limited access to dental care.

Evaluation of the clinical performance of dentures manufactured by computer-aided technology and conventional techniques: A systematic review

STATEMENT OF PROBLEM

The introduction of computer-aided design and computer-aided manufacturing (CAD-CAM) technology for complete denture fabrication may have improved clinical outcomes compared with conventional techniques. However, systematic reviews comparing these techniques are lacking.

PURPOSE

The purpose of this systematic review was to identify, compare, and synthesize the outcomes of published clinical studies related to complete denture fabrication, with respect to the differences between CAD-CAM technology and conventional techniques.

MATERIAL AND METHODS

A comprehensive search of studies published up to March 16, 2020, was conducted by using the PubMed/MEDLINE, Web of Science, Cochrane Library, SciELO, and Embase databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement criteria and was registered in the International Prospective Register of Systematic Reviews (PROSPERO ID 42020202614). The population, intervention, comparison, and outcome (PICO) question was: Do CAD-CAM complete dentures have a similar functional performance to those fabricated by conventional techniques? The quality of publications was appraised by using the Critical Appraisal Skills Program (CASP) checklists.

RESULTS

Of the 1232 titles, 6 articles were selected. The studies reported better retention of digitally manufactured complete dentures without denture adhesives than that of conventional complete dentures with or without denture adhesives. Other studies reported that dentures manufactured with digital systems were better adapted to tissue surfaces, required less clinical time, were lower in cost, and provided better experience and satisfaction to patients.

CONCLUSIONS

The assessment of CAD-CAM planning and manufacturing through clinical studies is ongoing. However, preliminary results indicate better clinical performance and lower overall costs of digital complete dentures than conventional dentures.

Comparison of CAD/CAM and Conventional Denture Base Resins: A Systematic Review

At present, complete dentures (CDs) remain the only treatment available for the majority of edentulous patients. CDs are primarily fabricated using a conventional method using polymethylmethacrylate (PMMA) resin. The steps involved in PMMA polymerisation directly affect the quality of the resin prosthetic base and any error reduces retention and occlusal accuracy of CDs. Furthermore, when using the conventional technique, the residual monomer alters the resin mechanical properties and may cause mucosal reactions. Recently, computer aided design and computer aided manufacture (CAD/CAM) techniques were increasingly used to fabricate CDs by machining resin discs that have been manufactured under high pressure and temperature. This systematic review compares CAD/CAM and conventional CDs according to their mechanical, physical and chemical characteristics, as well as the clinical impact of any differences between them. A review was conducted according to the preferred reporting items for systematic reviews and meta-analyses checklist on 392 publications from both PubMed and backward research. Fifteen studies have been included. Results showed that CAD/CAM resins had globally better physical and mechanical properties than conventional resins. The use of machined resin could improve the clinical performance, maintenance and longevity of CDs. Further studies in clinical use would be required to complement these results.

Properties of Acrylic Resin For CAD/CAM: A Systematic Review and Meta-Analysis of In Vitro Studies

PURPOSE

This systematic review and meta-analysis of in vitro studies compared the prepolymerized acrylic resin used for CAD/CAM complete denture manufacturing versus the heat-polymerized acrylic resin for conventional complete dentures in terms of surface roughness, wettability, hardness and flexural strength.

MATERIALS AND METHODS

An electronic search was performed in the PubMed, Embase, LILACS and Web of Science databases, without language or date restrictions. Gray literature and manual search tools were also used. The systematic review was carried out by two researchers independently, following the inclusion criteria: in vitro studies testing the CAD/CAM acrylic resin with a control group of heat-polymerized acrylic resin which compared at least one of the four material properties above. The meta-analysis was performed separately for each property, using a random effect model.

RESULTS

Of the 914 studies found by means of search strategies, 698 were selected for the systematic review. After applying the eligibility criteria, only 17 articles were selected for the qualitative analysis in the systematic review; among these, 14 were included in the quantitative meta-analysis. The CAD/CAM prepolymerized acrylic resin in blocks had similar properties when compared to heat-polymerized acrylic resin in almost all outcome measures, with the exception of a statistically significant reduction in surface roughness.

CONCLUSIONS

Based on the findings of this systematic review and meta-analysis, equally satisfactory results can be expected from dental prosthesis manufactured by the CAD/CAM system when compared to conventional ones, with the additional potential of reducing the pigmentation and attached microorganisms due to the reduced surface roughness of the prepolymerized resin.

Removal of denture adhesives from PMMA and Polyamide denture base materials

Denture adhesives need complete removal due to their frequent replacement.

A systematic review and meta-analysis to evaluate the efficacy of denture adhesives

OBJECTIVES

This systematic review aims to investigate the efficacy of denture adhesives (DAs) for complete dentures (CDs), and to provide clinical recommendations for prosthodontists and general practitioners.

DATA/SOURCES

Electronic databases (Medline, Embase, CENTRAL) and gray literatures were searched (up to March 2020) for relevant randomized and non-randomized controlled clinical trials (RCTs and CCTs) evaluating the efficacy of DAs when applied to CDs. Primary outcomes were objectively assessed variables directly related to mastication (denture retention, maximum bite force and masticatory efficiency). Secondary outcomes included other objectively assessed variables and patient-reported outcomes.

STUDY SELECTION

Of the 1729 records identified, 39 studies (43 articles) were included in the analysis. Among them, 23 were RCTs and 16 were CCTs, with two multicenter clinical trials (1 RCT and 1 CCT). Meta-analysis results indicated that DAs provided significantly higher retention (SMD 1.34, 95 % CI: 0.89-1.79, P < 0.001) for CDs. Bite force (SMD 0.98, 95 % CI: 0.50-1.47, P < 0.001) and masticatory performance (SMD 0.72, 95 % CI: 0.23-1.22, P = 0.004) of the CD wearers were also improved after using DAs, but the effect size was relatively smaller.

CONCLUSION

Based on the results of this systematic review, it is concluded that DAs can improve denture retention, bite force and masticatory performance of CD wearers.

CLINICAL SIGNIFICANCE

This study investigated the effects of all types of DAs for CDs in terms of their effects on denture retention, masticatory performance, oral health-related quality of life and oral microorganisms for CD wearers.

Should Digital Complete Dentures Be Part of A Contemporary Prosthodontic Education?

Digital complete dentures should be incorporated into a contemporary dental school education due to factors that include the substantial increase in the number of scientific publications devoted to digital dentures, the increased number of companies producing these prostheses, and the expanded use by practitioners. These factors increased recently due to multiple advantages of digital dentures that are described. Based on positive clinical experiences with such prostheses, preclinical curriculum changes were made with examples presented of both didactic and laboratory courses that now include digital dentures. Perspectives are presented regarding online laboratory procedures where a substantial portion can be performed at home through remote instruction.