Patient-reported outcome and cost-effectiveness analysis of milled and conventionally fabricated complete dentures in a university clinic: A retrospective study

STATEMENT OF PROBLEM

The custom disk is a novel method of complete denture fabrication; however, patient-reported outcomes and fabrication costs are unknown.

PURPOSE

The purpose of this retrospective study was to evaluate general patient satisfaction with complete dentures fabricated through the custom disk method. In addition, a comparative cost-effectiveness analysis was conducted for the custom disk method and conventional removable complete dentures.

MATERIAL AND METHODS

Complete dentures were fabricated for 44 edentulous participants by using the custom disk method (n=20) or the conventional removable complete denture (n=24). General patient satisfaction was measured by using visual analog scales before and after denture fabrication and compared by using the Wilcoxon signed-rank test (α=.05); the fabrication cost for each method was investigated and compared by using the Mann-Whitney U test (α=.05). Cost-effectiveness was analyzed with the incremental cost-effectiveness ratio as incremental cost per change in general patient satisfaction for the custom disk method with respect to the conventional removable complete denture.

RESULTS

The median general patient satisfaction with the custom disk method and conventional removable complete denture after the intervention was 84.0 mm and 91.0 mm, respectively. General patient satisfaction with the custom disk method was significantly higher after the intervention (P=.002). The median labor costs for the custom disk method and conventional removable complete denture were 24 516 and 36 583 Japanese yen, respectively, and the difference was statistically significant (P<.001). The median of the total cost of the custom disk method and the conventional removable complete denture was 41 104 and 45 276 Japanese yen, respectively, and the difference was statistically significant (P=.004). The incremental cost-effectiveness ratio was -251.4.

CONCLUSIONS

The custom disk method improved general patient satisfaction. The labor and total costs of the custom disk method were significantly lower than those of the conventional removable complete denture. The incremental cost-effectiveness ratio demonstrated that the custom disk method was more cost-effective than the conventional removable complete denture.

Effect of support structures on the trueness and precision of 3D printing dentures: An in vitro study

Purpose Additive manufacturing has revolutionized the fabrication of complete dentures. However, this process involves support structure, which is a construction part that holds the specimen during printing, and may prove to be disadvantageous. Therefore, this in vitro study compared the effect of support structure reduction on various volume and area distributions of a 3D-printed denture base to determine optimal parameters based on accuracy.Methods A complete maxillary denture base construction file was used as reference. Twenty denture bases were 3D printed under four conditions (total n=80): no support structure reduction (control), palatal support structure reduction (Condition P), border support structure reduction (Condition B), and palatal and border support structure reduction (Condition PB). Printing time and resin consumption were also recorded. The intaglio surface trueness and precision of all acquired data were exported to a 3D analysis software, and the dimensional changes to the denture base were analyzed using the root-mean-square estimate (RMSE) to assess geometric accuracy and generate color map patterns. Nonparametric Kruskal-Wallis and Steel-Dwass tests (α=0.05) analyzed the accumulated data.Results Control had the lowest RMSE values for trueness and precision. Nevertheless, it demonstrated a significantly lower RMSE than that of Condition B (P=0.02) in precision. Owing to negative deviation at the palatal region, Conditions P and PB had higher retention than Control and Condition B regarding the color map pattern.Conclusions Within the limitations of this study, the reduction of palatal and border support structures showed optimal accuracy with resource and cost savings.

Effects of build orientation and bar addition on accuracy of complete denture base fabricated with digital light projection: An in vitro study

PURPOSE

We evaluated the effects of build orientation and bar addition between lingual flanges on the accuracy of mandibular denture bases fabricated using a digital light processing (DLP) device.

METHODS

Mandibular denture bases with and without a bar at the lingual flanges were virtually designed and assigned to eight build orientations. Six dentures per condition were fabricated using a DLP device with a methacrylate-based photopolymerizable monomer (Dima Print denture base) (n=96). The fabricated denture surfaces were digitized, and intaglio surfaces were obtained. These digitized surfaces were compared via superimposition using graphical software (Artec studio12 profession) to their original designed files, and root mean square estimates were obtained. The trueness of the entire and intaglio data was statistically analyzed non-parametrically.

RESULTS

The range of trueness of the entire and intaglio denture bases was 0.15-0.31 mm and 0.11-0.38 mm, respectively. The trueness at 135° and 270° for the entire denture base and that at 270° for the intaglio data without the bar were significantly lower than those for the other build orientations. The trueness at 270° was <0.15 mm irrespective of the conditions. The trueness with the bar of all build orientations, except that of 0° for intaglio data, was significantly smaller than or equal to the trueness without the bar of the corresponding build orientations.

CONCLUSIONS

Build orientation and bar addition influenced the accuracy of the complete dentures fabricated using DLP. A build orientation of 270° is recommended for fabricating a mandibular complete denture, irrespective of the bar addition.

Oral function of implant-assisted removable partial dentures with magnetic attachments using short implants: A prospective study

OBJECTIVES

This prospective study aimed to compare the oral functions of removable partial dentures (RPDs) with those of implant-assisted removable partial dentures (IARPDs) with short implants and magnetic attachments in patients with mandibular Kennedy class I and II.

MATERIAL AND METHODS

Thirty participants with mandibular Kennedy class I or II and at least three distal missing teeth were recruited. Oral functions, including mixing ability, comminuting ability, maximum bite force, and occlusal contact area, were assessed for RPDs (stage 0), IARPDs with healing caps (stage 1), and IARPDs with magnetic attachments (stage 2). The implants were loaded with occlusal force in stages 1 and 2. Finally, the data of the 27 participants who completed the evaluation at stage 2 were analyzed. The Wilcoxon signed-rank test with Bonferroni correction was used to assess the differences in the oral functions among the different stages.

RESULTS

The implant survival rate was 93.8%. There were significant differences in the comminuting ability and occlusal contact area between stages 0 and 2 (p < .001 and p = .036, respectively) and stages 1 and 2 (p = .003 and p = .015, respectively). Regarding the maximum bite force, there was a significant difference between stages 1 and 2 (p = .018). However, there was no significant difference in the mixing ability between the three stages.

CONCLUSIONS

Within the limitations of this study, it was concluded that IARPDs in the mandible with short implants and magnetic attachments may improve oral functions.

Effect of post-rinsing time and method on accuracy of denture base manufactured with stereolithography

PURPOSE

MATERIALS AND METHODS

RESULTS

CONCLUSION

Comparison of general satisfaction, oral health-related quality of life, and patient's self-assessment between mandibular single-implant overdentures and experimental removable complete dentures: A randomized crossover clinical trial

Objective Patient satisfaction with single-implant overdentures (1-IODs) is unclear. This randomized crossover trial aimed to compare the general satisfaction, oral health-related quality of life, and patients' self-assessment between mandibular 1-IODs and experimental removable complete dentures (eRCDs). Methods New mandibular RCDs were fabricated for 22 patients with edentulous mandibles. After adapting to the RCDs, one implant was inserted in the mandibular midline. The participants were then randomly classified into groups 1 and 2. Group 1 received IODs for the first 2 months, while group 2 used eRCDs with a non-loaded implant in the midline. After 2 months, the treatment was switched. Four validated, patient-reported dental outcome measures were assessed: general satisfaction, Japanese version of the Oral Health Impact Profile for edentulous subjects (OHIP EDENT-J), General Oral Health Assessment Index (GOHAI), and Patient's Denture Assessment (PDA). The assessments were performed at the end of the IOD- and eRCD- use periods. Results General satisfaction was significantly higher during the IOD period (p = 0.002). Significant differences were observed in all domains of the OHIP, except orofacial pain (p = 0.084). Further, the total score (p<0.001) and the scores of the physical (p<0.001) and psychosocial functioning (p = 0.001) domains of the GOHAI differed significantly. The total PDA score (p = 0.001) and the scores of the function (p = 0.004), lower denture (p = 0.002), esthetics and speech (p = 0.026), and importance (p = 0.009) domains were significantly higher during the IOD period than during the eRCD period. Conclusion General satisfaction, oral health-related quality of life, and patient self-assessment scores were significantly higher for 1-IODs than for eRCDs. Clinical significance Within the limitations of this study, we found that mandibular single-implant overdentures may be an efficient alternative to mandibular experimental removable complete dentures due to higher general satisfaction, oral health-related quality of life, and patient self-assessment scores of dentures.

Patient-reported outcomes of implant-assisted removable partial dentures with magnetic attachments using short implants: A prospective study

PURPOSE

Implant-assisted removable partial dentures (IARPDs) with short implants improve the oral functions of removable partial dentures (RPDs). This study aimed to compare the patient-reported outcomes of RPDs and IARPDs with short implants retained by magnetic attachments.

METHODS

We recruited 30 participants with mandibular Kennedy Class I or II and distal extension defects of three or more teeth. RPDs, IARPDs with a healing cap, and IARPDs with a magnetic attachment were evaluated across stages using patient-reported outcomes. All participants completed questionnaires (oral health-related quality of life [OHRQoL], patient general satisfaction, and patient's denture assessment [PDA]) at each stage. The OHRQoL was evaluated using the Oral Health Impact Profile-J 54 (OHIP-J 54) score. The general patient satisfaction was evaluated using a 100 mm visual analog scale. The Wilcoxon signed-rank test and Bonferroni correction were used to evaluate differences between the groups (α=0.05).

RESULTS

The OHRQoL of IARPDs was significantly higher than that of RPDs. IARPDs with a magnetic attachment had significantly better patient general satisfaction and PDA than IARPDs with a healing cap.

CONCLUSIONS

The OHRQoL, patient general satisfaction, and PDA were improved by IARPD with a short implant using a magnetic attachment.

Masticatory performances and maximum occlusal forces of immediate and conventional loaded two-implant supported overdentures retained by magnetic attachments: preliminary study of randomized controlled clinical trial

Background

The appropriate loading protocol to improve masticatory performance (MP) is still unclear in elderly patients and two-implant overdentures (2-IODs) wearers. This study aimed to compare the long-term MP and maximum occlusal force of immediate loading (IL) and conventional loading (CL) of 2-IODs retained by magnetic attachments. Nineteen edentulous patients were randomly assigned to either an IL (n=10) or CL group (n = 9). In the IL group, the implant was loaded on the same day as insertion, whereas it was loaded 3 months after insertion in the CL group. Magnetic attachments were used to retain all overdentures to the implants. MP, measured by a piece of color-changeable chewing gum and a gummy jelly test, and maximum occlusal force, measured using an occlusal force measuring device, were assessed in both groups at baseline and at 3-, 4-, and 5-year follow-ups.

Results

No significant differences were observed in the MP and the maximum occlusal force between the IL and CL groups at any time point. However, a significantly higher MP was observed at the 3-year time point in the IL group (P = 0.036). The maximum occlusal force revealed a significant correlation with MP, both with the color-changeable chewing gum and gummy jelly at 5 years.

Conclusion

After long-term observation, no significant differences in MP and maximum occlusal force were observed between the IL and CL groups. However, compared to pre-implant insertion of the complete denture, the MP in the IL group significantly improved at 3 years. Furthermore, the maximum occlusal force was significantly correlated with MP at 5 years.

Trial registration

UMIN, UMIN000009889. Registered on 28 January 2013.

Comparison of Mechanical Properties of PMMA Disks for Digitally Designed Dentures

In this study, the physical properties of a custom block manufactured using a self-polymerizing resin (Custom-block), the commercially available CAD/CAM PMMA disk (PMMA-disk), and a heat-polymerizing resin (Conventional PMMA) were evaluated via three different tests. The Custom-block was polymerized by pouring the self-polymerizing resin into a special tray, and Conventional PMMA was polymerized with a heat-curing method, according to the manufacturer’s recommended procedure. The specimens of each group were subjected to three-point bending, water sorption and solubility, and staining tests. The results showed that the materials met the requirements of the ISO standards in all tests, except for the staining tests. The highest flexural strength was exhibited by the PMMA-disk, followed by the Custom-block and the Conventional PMMA, and a significant difference was observed in the flexural strengths of all the materials (p < 0.001). The Custom-block showed a significantly higher flexural modulus and water solubility. The water sorption and discoloration of the Custom-block were significantly higher than those of the PMMA-disk, but not significantly different from those of the Conventional PMMA. In conclusion, the mechanical properties of the three materials differed depending on the manufacturing method, which considerably affected their flexural strength, flexural modulus, water sorption and solubility, and discoloration.

Effect of Printing Direction on the Accuracy of 3D-Printed Dentures Using Stereolithography Technology

This study evaluated the effects of the differences in the printing directions of stereolithography (SLA) three-dimensional (3D)-printed dentures on accuracy (trueness and precision). The maxillary denture was designed using computer-aided design (CAD) software with an STL file (master data) as the output. Three different printing directions (0°, 45°, and 90°) were used. Photopolymer resin was 3D-printed (n = 6/group). After scanning all dentures, the scanning data were saved/output as STL files (experimental data). For trueness, the experimental data were superimposed on the master data sets. For precision, the experimental data were selected from six dentures with three different printing directions and superimposed. The root mean square error (RMSE) and color map data were obtained using a deviation analysis. The averages of the RMSE values of trueness and precision at 0°, 45°, and 90° were statistically compared. The RMSE of trueness and precision were lowest at 45°, followed by 90°; the highest occurred at 0°. The RMSE of trueness and precision were significantly different among all printing directions (p < 0.05). The highest trueness and precision and the most favorable surface adaptation occurred when the printing direction was 45°; therefore, this may be the most effective direction for manufacturing SLA 3D-printed dentures.

Evaluation of dimensional accuracy and degree of polymerization of stereolithography photopolymer resin under different postpolymerization conditions: An in vitro study

STATEMENT OF PROBLEM

The appropriate postpolymerization of stereolithography (SLA) resins with the least effect on dimensional accuracy and with optimal polymerization is unclear.

PURPOSE

The purpose of this in vitro study was to investigate the dimensional accuracy and degree of polymerization of a photopolymer resin for SLA with different postpolymerizing times and temperatures.

MATERIAL AND METHODS

Sixty 1.5-mm-thick specimens were made from clear photopolymer resin with a 3D printer to simulate a maxillary complete denture. They were postpolymerized for different periods (15 and 30 minutes) at 3 different temperatures (40 °C, 60 °C, and 80 °C). Both prepolymerization and postpolymerization gap sizes for each specimen were measured at 5 different locations under a stereomicroscope. The tissue surface was scanned before and after polymerization, and the images were superimposed. The deviation was analyzed by using computer-aided design (CAD) software; root mean square estimates (RMSE) and color map data were obtained. Fourier transform infrared spectrometry was used to determine the degree of conversion (DC) of all specimens. The Kruskal-Wallis and Mann-Whitney tests were used to calculate the difference value of the gap sizes (α=.05). One-way ANOVA and the Tukey test were used for RMSE and DC (α=.05).

RESULTS

The smallest average change in gap sizes was found at 15 minutes and 40 °C, and the largest change at 30 minutes and 80 °C. The lowest RMSE was obtained at 30 minutes and 40 °C (P<.05). On the color map, a uniform deposited layer was created at 15 minutes and 40 °C and 30 minutes and 40 °C. The highest DC was found at 30 minutes and 60 °C, which differed significantly from 15 minutes and 40 °C (P<.05). The lowest degree of polymerization was found at 30 minutes and 40 °C.

CONCLUSIONS

The polymerizing temperature exerted a greater effect than polymerizing time, with lower temperatures leading to improved fit and tissue surface accuracy. The recommended parameters for SLA polymerization are 15 minutes and 40 °C. These conditions offered high dimensional accuracy, favorable surface tissue adaptation, and satisfactory DC.