Evaluation of The Effect of Thermocycling on The Trueness And The Precision of Digital Fabricated Complete Denture Bases

doi:10.21203/rs.3.rs-3601350/v1

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Research Article

Evaluation of The Effect of Thermocycling on The Trueness And The Precision of Digital Fabricated Complete Denture Bases

https://doi.org/10.21203/rs.3.rs-3601350/v1

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published 23 Aug, 2024

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Background

Many denture base materials are available nowadays in the market, with little data available regarding its dimensional stability after exposure to the oral environment.

Purpose

was to evaluate the effect of thermocycling on the trueness and precision of digital fabricated complete denture bases (CDBs) (milled and 3-dimensional (3-D) printed CDBs) and conventional CDB.

Materials and methods

Maxillary completely edentulous stone model was used and scanned for production a standard tessellation language (STL) file that was imported to a metal milling machine software to produce the metal model that was used to fabricate 30 CDBs, according to the construction technique the CDBs were divided into three groups (n = 10 each) as follows: Group 1, CAD-CAM milled CDBs; Group 2, 3-D printed CDBs; and Group 3, conventional compression molded CDBs. The CDBs of all groups were scanned after fabrication, and the different CDBs were scanned and evaluated CDBs before and after thermocycling using the superimposition technique. Data were analyzed using one-way-ANOVA, Tukey’s post hoc, and paired t tests.

Results

Before and after thermocycling there were a significant difference in the trueness between the CAD-CAM milled, 3-D printed, and conventional compression molded CDBs (P < 0.05). There was a significant difference in the precision within each type of different CDBs before and after thermocycling (P < 0.05). Conclusion: the trueness of the CAD-CAM milling system in CD fabrication is superior to that of the 3-D printing and conventional compression molding systems either before or after thermocycling. The thermocycling had significant effect on the precision of milled CAD-CAM, 3-D printed and conventional compression molded CDBs. Conventional compression molding system in complete denture construction is the most negatively affected fabrication method by thermocycling in the aspect of trueness and precision.

Additive technique

CAD-CAM

Precision

Subtractive technique

Superimposition

Thermocycling

Trueness.

Most completely edentulous patients preferred the complete dentures (CD) as a favorite option due to its least invasive and cost-effective. One of the critical features that affecting the quality of complete denture bases (CDBs) is its degree of fitness to underlying tissue structures; CDBs that fit well provide better primary comfort and lower the risk of traumatic ulcers. The most significant aspect for good retention in CDBs is tissue congruent denture fit. CDBs' retention has a great effect on masticatory efficiency and speaking ability, and thus on the patients' quality of life. As a result, one of the key goals in CDBs fabrication should be to obtain maximum tissue congruence [1, 2].

During the polymerization, cooling, and finishing operations, the polymethyl-methacrylate (PMMA) denture base deforms by 0.45 to 0.9 percent linearly. To manage the amount of polymerization shrinkage, numerous investigations of production processes, denture base materials, and clinical protocols have been made. By injecting unpolymerized acrylic resin into the mold, the pressure injection molding technique was tested to improve the dimensional accuracy of the compression molding process [3, 4].

Prior to the development of computer-aided design-computer-aided manufacturing (CAD-CAM) technology in the field of dental prosthetics, the shrinkage of the resin during polymerization prevented the correspondence between the CDBs and tissues that support dentures from being achieved. Deformities generated by this shrinkage on CDBs had a negative effect on CD retention and fit. On the other hand, the CAD-CAM system for the manufacture of CDBs is based on a subtractive method. Since CDBs are milled from fully polymerized acrylic resin pucks, they are resistant to distortion and shrinkage [5].

For the past 20 years, CAD-CAM technology has been widely employed in dentistry to create a variety of dental prosthesis because to its benefits of enhanced production and efficiency, reduced turnaround time, and improved treatment protocol accuracy [4, 6].

Recently, CD production using a CAD-CAM system has proliferated in both clinical and laboratory contexts. This broad adoption in the dental industry could be attributed to improvements in the CAD-CAM technique, which have raised the level of knowledge among dental professionals and laboratory technicians and increased their capacity to integrate elements of the digital workflow with conventional clinical and laboratory protocols [7].

The two most popular digital methods for CD creation are CAD-CAM technology, which employs the subtractive milling process, and rapid prototyping system, also known as 3-D printing, which is an additive manufacturing technique [8, 9].

CAD-CAM milled, and 3-D printed dentures are advantageous to both professionals and patients. Five appointments are normally required for CD construction, which is time-consuming for both the technician and the dentist. Digitally manufactured dentures can be delivered in as few as two sessions, which significantly reduces the amount of time needed. Patient records are digitally stored by the producing business. If a patient's denture is damaged or destroyed, a quick and accurate replacement prosthesis can be created without the need for additional clinical documentation [10, 11].

Depending on the fabrication method, there are two different kinds of CAD-CAM technologies: milling and 3-D printing. Each of these methods makes use of the intraoral scanner to record the patient's oral data. The milling technique has some drawbacks, including inevitable material loss during milling, high equipment maintenance costs, significant time waste during the production process, as well as the dependence of restoration accuracy on the size of the milling burs and the wear, tear, and brief lifetime of the milling tools [12–14]. The ability to produce several objects at once and the ability to create the needed models and prostheses with a small amount of material are advantages of 3-D printing, which relies on additive manufacturing and builds the object using the layer-by-layer process. This capability of repetitive production considerably promotes clinical efficiency. Due of these advantages, 3-D printer use in dentistry has substantially increased since their creation [15–17].

In dentistry nowadays, 3-D printing is utilized to create diagnostic models, orthodontic treatment plans, implant surgical guides, and fabricate specialized orthodontic equipment. However, the existing 3-D printing technique's value and precision are insufficient to create models for prosthesis [18–21].

The evaluation of the dimensional accuracy of the CAD-CAM milled, 3-D printed, and conventional compression molded CDBs has been reported [6]. However, this report did not compare between the effect of thermocycling on the trueness of the CAD-CAM milled, 3-D printed, and conventional compression molded CDBs. Moreover, there is limited data available in the literature regarding the effect of thermocycling on the precision of types of CDBs. Therefore, this study aimed to evaluate the effect of thermocycling on the trueness and precision of the CAD-CAM milled, 3-D printed, and conventional compression molded CDBs.

The null hypotheses of this study were that the differences in trueness between CAD-CAM milled, 3-D printed, and conventional compression molded CDBS and in the precision within each type of different CDBs before and after thermocycling would be insignificant.

A power analysis was designed to permit the application of statistical tests for the null hypothesis that there is no difference in the dimensional accuracy between the groups. By adopting an alpha level of 0.05, beta level of 0.05 (i.e., power = 95%), and effect size of 0.759 and calculations based on the results of the study by Kalberer et al. [7], the predicted sample size was 30 samples (ten samples/group). Sample size calculation was performed using G*Power, version 3.1.9.7 [8].

In total, 30 maxillary CDBs were used in this study. The CDBs were divided into three groups based on the processing technique and resin composition (n = 10 in each): Group 1 (G1), CAD-CAM milled CDBs; Group 2 (G2), 3-D printed CDBs, and Group 3 (G3), conventional compression molded heat-cured PMMA CDBs.

A ready-made maxillary stone model that was totally edentulous was employed for this study [6, 10]. The reference CAD master stone model's STL file was created by scanning the master stone model with an optical extra-oral 3-D scanner (Germany's Dentsply Sirona inEos X5).

A preview of the 3-D cast model was sent for approval after it had been virtually created using CAD software (ExoCad, Chairside Cad 2.3 Matera, Germany), and the manufacturing of the edentulous metal master cast was approved. The reference CAD model file's scan data was used to create the digital metal cast. The metal cast was created using a CAD-CAM metal milling machine (Redon Hybrid CAD-CAM metal milling machine, Turkey) and a CAD metal disc (Vsmile titanium grade 5 98*25mm universal, China). Burs of three different diameters of 2 mm, 1 mm, and 0.5 mm, respectively, were used in the milling process of the metal model. One set of milling burs were used for milling a single block to maintain the same condition during the milling process [16].

The metal master cast was then finished and polished using standard techniques. An optical extra-oral 3-D scanner was used to scan the reference CAD master metal model, and the resulting data was recorded as an STL file. During scanning procedures, a scanning spray (Telescan spray-white, Germany) was utilized to eliminate out the metal model's reflections [14].

CAD-CAM milled CDBs processing (G1)

Ten CAD-CAM milled CDBs were fabricated as following [14, 18]

The STL file of the scanned metal model was exported to the CAD software. Upon receiving the scan data, the STL file was imported into ExoCad design software, where the anatomical landmarks were automatically detected and indicated.

After approval of the virtual design preview, the designed virtual CDBs were exported to the CAM milling machine (Dentsply Sirona In Lab MC X5 laboratory milling machine, Germany). Pre-polymerized CAD-CAM PMMA acrylic pucks (AvaDent Digital Dental solutions HQ, USA) were then milled into CDBs.

The outline of the CDB was produced using a bur with a maximum diameter of 2.5 mm, while the finer details were made using a bur with a minimum diameter of 1 mm. The manufacturer's recommendations were followed, and the milling operation was set to five-axis machining to accurately produce the small details and was carried out in moist conditions to prevent overheating [15].

3-Dprinted CDBs processing (G2)

Ten 3-D printed CDBs were fabricated based on the previously described virtual design as following [9]

The designed CDBs were exported as STL files to the 3-D printer (WANHAO desktop 3-D printer, China) and printed according to Digital Light Projection (DLP) technology using photo-polymerized 3-D printed liquid (Harz Labs, Russian Federation, Moscow).

Before printing, the HarzLabs liquid was put into the supply chamber of the 3-D printer and shaken for roughly 5 minutes. The CDBs were printed at a layer thickness of 100 µ/layer with a 45° orientation. These layers were cured successively and bonded together to fabricate the desired CDB. The layers bonded to each other due to the inherent property of the material to be self-adherent. To remove any extra material, the finished printed CDBs were twice rinsed in isopropyl alcohol (99% concentration) for 3 minutes and 2 minutes, respectively. After that, for an additional 15 minutes of polymerization, they were placed in an ultraviolet (UV) light-curing box (Anycubic wash and cure light box, Shenzhen, China).

Conventional compression heat-cured CDBs processing (G3)

Ten conventional CDBs were processed using the conventional compression molding technique of heat-cured PMMA acrylic resin (Vertex-Dental BV. Headquarters the Netherlands) as described below [10].

For this group of CDBs, a specially designed stone mold was made using the reference CAD metal model. According to the manufacturer's recommendations, the heat-cured PMMA powder and liquid were mixed in a glass jar at a 3:1 polymer to monomer ratio until the dough stage was reached. The two halves of the dental flask were closed together and placed under hydraulic compression pressure, which was slowly applied on the flask for the resin dough to flow throughout the mold space.

The flask was then immersed in a thermostatic temperature-controlled water bath for curing. The PMMA was cured and polymerized in a long curing cycle according to the manufacturer’s instructions. The curing cycle involved placing the flask in water at 70°C for 9 hours. The flask was removed from the curing bath and cooled slowly for 30 minutes to room temperature. The mold was then opened, and the CDBs were removed, and excess acrylic was trimmed.

After all the CDB specimens of this study were constructed, they were finished using tungsten carbide acrylic burs (Edenta AG; Au; Switzerland) and silicon carbide papers. The specimens were further polished using rubber acrylic burs (Edenta), pumice (Shera; Lemfo ̈rde; Germany), and rouge (Dialux; Lu ̈denscheid; Germany). Only one surface was polished, while the interior surface was kept untouched to simulate the oral surfaces as much as possible [11].

Trueness evaluation

The intaglio surfaces of the thirty CDBs were scanned using an optical extra-oral 3-D scanner (Dentsply Sirona inEos X5, Germany) and stored as STL files to assess the trueness of the CDBs of various groups.

Superimposition evaluation technique was performed as described below [21]:

Surface matching software (Geomagic Control X, 3-D Systems, Canada) was used to superimpose the STL files of the scanned intaglio surfaces of the 30 dentures on the STL file of the scanned reference model with a best-fit alignment to assess the trueness and congruence of the CDs with the model. The vertical distances between the superimpositions were calculated by the software. The findings were shown as color maps, with yellow to red denoting CDB impingement on the cast, blue denoting separation between the CDB and cast, and green denoting contact between the CDB and cast. The closer the value is to 0, the more accurate and adaptive is the fabrication technique.

Precision evaluation

To evaluate the precision of the CDBs of different groups, the master cast surface was also divided in five functionally relevant sections (anterior ridge crest, posterior ridge crest, maxillary tuberosity, palatal vault, and posterior palatal seal) to evaluate the region-specific mismatches.

Thermocycling:

A thermocycling protocol simulating six months of intraoral use was applied to all specimens. The dentures were immersed alternately in deionized water at 5 and 55°C for 5000 cycles [5]. After thermocycling, the scanning and matching procedures were repeated, following the mentioned protocol.

Statistics

Data were collected and statistically analyzed using ANOVA test to determine whether significant differences existed between the means of the trueness of the tested groups, also Tukey’s post hoc (TPH) test was used for pair-wise comparisons between groups at the chosen level of probability (P < 0.05). However, the Paired t-test was employed to study the effect of thermocycling on the precision at different sites within the same group at the chosen level of probability (P < 0.05) using Statistical Product and Service Solutions, version 20 (SPSS; Inc.; IBM Corporation; NY; USA) for Windows and Graph Pad Prism, version 8 (Graph Pad Prism Company; USA).

Overall denture fit: The informative statistical analyses of the different groups (Pre- and Post-thermocycling) using one-way ANOVA are listed in Table 1.

Table 1

Means and standard deviations (mm) of the trueness of the tested groups, one-way ANOVA test, and the pairwise comparisons between tested groups (before and after thermocycling).
	Superimposition measurements	ANOVA test P-value	Tukey post hoc test
	Mean ± SD (mm)		Tukey post hoc test
	Mean ± SD (mm)		Pair-wise Comparisons	P-value
Group1 (Before thermocycling)	0.60 ± 0.023	0.0001*	Group1 vs Group2	< 0.0001*
Group 2 (Before thermocycling)	0.96 ± 0.032		Group1 vs Group3	< 0.0001*
Group 3 (Before thermocycling)	0.93 ± 0.024		Group2 vs Group3	0.046*
Group 1 (After thermocycling)	0.67 ± 0.089	0.0001*	Group1 vs Group2	< 0.0001*
Group 2 (After thermocycling)	1.06 ± 0.06		Group1 vs Group3	< 0.0001*
Group 3 (After thermocycling)	1.56 ± 0.15		Group2 vs Group3	< 0.0001*
*; Significant level at p ≤ 0.05

The one-way-ANOVA test revealed a statistically significant (P < 0.05) between the different groups before thermocycling. Whereas the means and standard deviations of the overall misfit of the tested groups before thermocycling are 0.6 ± 0.023, 0.96 ± 0.032, and 0.93 ± 0.024 for groups 1, 2, and 3 respectively. TPH test showed statistically significant differences between group1 and group2, group1 and group3, and group2 and group3 (P < 0.05), Fig. 1 (1a, 2a, & 3a).

Also, after thermocycling the one-way ANOVA revealed a statistically significant (P < 0.05) between the different groups. The means and standard deviations of the overall misfit of the tested groups are 0.67 ± 0.089, 1.06 ± 0.06, and 1.56 ± 0.15 for groups 1, 2, and 3 respectively. TPH test showed statistically significant differences between group1 and group2, group1 and group3, and group2 and group3 (P < 0.05), Fig. 1 (1b, 2b, & 3b).

Region-specific misfit: For groups 1; Paired T-test revealed statistically significance differences (P < 0.05) in the aspect of precision for the effect of thermocycling in posterior palatal seal are only, while there are not statistically significance differences (P˃0.05) in the other areas (Anterior ridge crest, posterior ridge crest, maxillary tuberosity, palatal vault, and overall) as shown in Tables 2 and Fig. 1 (1a&1b).

Table 2

Means and standard deviations (mm), and pair-wise comparisons (using Paired T test) of different regions and overall misfit in the term of precision of Group 1 (before and after thermocycling)
	Mean	Std. Deviation	95% Confidence Interval of the Difference		Paired T test
			Lower	Upper	P-value
Anterior ridge crest (Pre-thermocycling)	0.5791	0.17738	-0.27779	0.21197	0.768
Anterior ridge crest (Post-thermocycling)	0.6120	0.18746
Posterior ridge crest (Pre-thermocycling)	0.6292	0.19272	-0.26917	0.23351	0.876
Posterior ridge crest (Post-thermocycling)	0.6470	0.19818
Maxillary tuberosity (Pre-thermocycling)	0.6178	0.18924	-0.19014	0.18592	0.980
Maxillary tuberosity (Post-thermocycling)	0.6199	0.18988
Palatal vault (Pre-thermocycling)	0.5777	0.17696	-0.19017	0.13956	0.736
Palatal vault (Post-thermocycling)	0.6030	0.18471
Posterior palatal seal (Pre-thermocycling)	0.5963	0.18264	-0.49581	-0.03588	0.028*
Posterior palatal seal (Post-thermocycling)	0.8621	0.26407
Overall (Pre-thermocycling)	0.6000	0.023	-0.18091	0.04331	0.198
Overall (Post-thermocycling)	0.6688	0.08921
*; Significant level at p ≤ 0.05

While for group 2; Paired T-test revealed statistically significance differences (P < 0.05) in the aspect of precision for the effect of thermocycling in posterior palatal seal area and overall, while there is not statistically significance differences (P˃0.05) in the other areas (Anterior ridge crest, posterior ridge crest, maxillary tuberosity, and palatal vault) as shown in Tables 3 and Fig. 1 (2a&2b).

Table 3

Means and standard deviations (mm), and pair-wise comparisons (using Paired T test) of different regions and overall misfit in the term of precision of Group 2 (before and after thermocycling).
	Mean	Std. Deviation	95% Confidence Interval of the Difference		Paired T test
			Lower	Upper	P-value
Anterior ridge crest (Pre-thermocycling)	1.0025	0.27697	-0.19352	0.16770	0.875
Anterior ridge crest (Post-thermocycling)	1.0154	0.28054
Posterior ridge crest (Pre-thermocycling)	0.9421	0.26028	-0.21999	0.19014	0.873
Posterior ridge crest (Post-thermocycling)	0.9570	0.26440
Maxillary tuberosity (Pre-thermocycling)	0.9771	0.26996	-0.19611	0.16231	0.836
Maxillary tuberosity (Post-thermocycling)	0.9940	0.27463
Palatal vault (Pre-thermocycling)	0.9191	0.25392	-0.14641	0.13053	0.900
Palatal vault (Post-thermocycling)	0.9270	0.25612
Posterior palatal seal (Pre-thermocycling)	0.9593	0.26503	-0.77059	-0.17887	0.005*
Posterior palatal seal (post-thermocycling)	1.4340	0.32749
Overall (Pre-thermocycling)	0.9600	0.032	-0.19520	-0.01576	0.026*
Overall (Post-thermocycling)	1.0655	0.05977
*; Significant level at p ≤ 0.05

While in the group 3, the paired T-test revealed statistically significance difference (P < 0.05) in the aspect of precision for the effect of thermocycling in all areas (Anterior ridge crest, posterior ridge crest, maxillary tuberosity, palatal vault, posterior palatal seal, and overall) as shown in Table 4, Fig. 1 (3a&3b).

Table 4

Means and standard deviations (mm), and pair-wise comparisons (using Paired T test) of different regions and overall misfit in the term of precision of Group 3 (before and after thermocycling).
	Mean	Std. Deviation	95% Confidence Interval of the Difference		Paired T test
			Lower	Upper	P-value
Anterior ridge crest (Pre-thermocycling)	0.9428	0.29931	-0.83830	-0.44418	0.000*
Anterior ridge crest (Post-thermocycling)	1.5840	0.25720
Posterior ridge crest (Pre-thermocycling)	0.9603	0.30487	-1.04650	-0.36895	0.001*
Posterior ridge crest (Post-thermocycling)	1.6680	0.31955
Maxillary tuberosity (Pre-thermocycling)	0.8966	0.28466	-0.87940	-0.42141	0.000*
Maxillary tuberosity (Post-thermocycling)	1.5470	0.27569
Palatal vault (Pre-thermocycling)	0.9196	0.29196	-1.00088	-0.23593	0.005*
Palatal vault (Post-thermocycling)	1.5380	0.36207
Posterior palatal seal (Pre-thermocycling)	0.9308	0.29551	-0.90140	-0.21105	0.005*
Posterior palatal seal (Post-thermocycling)	1.4870	0.35389
Overall (Pre-thermocycling)	0.9300	0.024	-0.79403	-0.47557	0.000*
Overall (Post-thermocycling)	1.5648	0.15087
*; Significant level at p ≤ 0.05

In the current study one metal model was used for the construction of thirty CDBs of different groups. A metal model was used instead of stone model due to its superior resistance to temperatures during the repeating conventional compression heat curing process 10 times for construction ten CDBs of group3.

To detect the most area that affected by thermocycling and undergone the discrepancy in each type of the tested CDBs and to evaluate the region-specific mismatches the master cast surface was divided in five functionally sections (anterior ridge crest, posterior ridge crest, maxillary tuberosity, palatal vault, and posterior palatal seal).

Clinicians consider the CDBs' accuracy as one of the most important features in all prosthesis construction approaches [4]. Since the usage of PMMA in the creation of CDBs, dimensional inaccuracy due to polymerization shrinkage has been inescapable [3]. The accuracy, retention, and stabilization of dentures are impacted by polymerization shrinkage, which also has an impact on patient satisfaction and quality of life [1].

The results of the current study revealed that there was a statistically significant difference (P < 0.05) between the trueness of the different CDBs before and after thermocycling, also there were significant effect for the thermocycling on the precision within each type of the tested CDBs (P < 0.05). Hence, the null hypotheses that there would be no significant differences in the trueness between the CAD-CAM milled, 3-D printed, and conventional compression molded CDBs before and after thermocycling and no significant the effect of thermocycling on the precision within each type of CDBs were rejected.

The findings revealed that the CAD-CAM milled group's trueness was significantly higher before and after thermocycling than that of the 3-D printed and traditional compression molded groups (P < 0.05). This could be explained by the fact that the 5-axis CAD-CAM milling machine was utilized, however the 3-D printing was carried out utilizing a DLP 3-D printer with a 100-µm/layer and only 3-axis machining. Therefore, the CAD-CAM milled CDBs had greater dimensional accuracy than the 3-D printed CDBs [15]. Other possible causes that of 3-D printed CDBs is the material constitution, fabrication technique in consecutive layers, or enhanced water sorption with thermal stress [22].

Regarding the aspect of precision and region-specific misfit of the CAD-CAM milled and 3-D printed groups the posterior palatal seal was the only area that was significantly affected by thermocycling (P < 0.05), however all areas (Anterior ridge crest, posterior ridge crest, maxillary tuberosity, palatal vault, posterior palatal seal, and overall) that were tested for the conventional compression molded CDBs were significantly affected by thermocycling (P < 0.05). This may be due to the lower degree of polymerization and weak double bond conversion in addition to excessive residual monomer that were might be affected by thermal changes and water sorption that may lead to changes in the mechanical properties and dimensional accuracy [23–25], also the water absorption by the acrylic resin causing subsequent leach out of plasticizers and breakage of resin material [26].

The precision of the posterior palatal seal area in each type of the tested CDBs was the most significant affected area by the thermocycling (P < 0.05), however the anterior ridge crest, posterior ridge crest, maxillary tuberosity, and palatal vault areas had been significantly affected by thermocycling only in conventional compression molded CDBs (P < 0.05). This result verified with that of the study by Steinmassl O et al. [5].

According to the findings of our investigation, Sykora et al. [2] study stated that the fabrication methods used to create the maxillary CDs have an impact on how well the CDB fits. Depending on the measurement region, the CDs' misfit differs. This was supported by the findings of Goodacre et al. [10], who reported that in the maxillary CD fabrication at the edge of denture border, 6mm away from denture border, crest of the alveolar ridge, palate, and posterior palatal seal, the degree of misfit was less with the CAD-CAM milling method than with the molding method. Furthermore, Steinmassl et al. [5] demonstrated that the alveolar ridge and palate regions in almost all CAD-CAM manufacturing systems showed the highest degree of accurate fit, whereas the anterior and lateral, and posterior seal regions showed the highest degree of misfit. Others found that the conventional denture group's precision of fit was superior to that of the CAD/CAM milled dentures [27].

The difference in the results of the current study and the others may be due to the difference in materials used or in the methodology.

The absence of long-term water storage and oral circumstances (a wet environment) simulations, as well as the fact that neither the salivary contents nor the various beverages were simulated, are the study's weaknesses. Additionally, using various printing resins and printers may lead to differences in the output. Therefore, additional research is required to determine how wet conditions and long-term water storage affect the precision of conventional and digitally manufactured denture bases, as well as their mechanical and physical characteristics.

We draw the conclusion that the CAD-CAM milling technique used in CD production is more accurate than 3-D printing and conventional compression molding systems, both before and after thermocycling, based on this study's limits and findings. The precision of milled CAD-CAM, 3-D printed, and conventional compression molded CDBs was significantly impacted by thermocycling. In terms of trueness and precision, thermocycling has the greatest negative impact on the conventional compression molding technology used in the manufacturing of complete dentures. Additionally, among the other locations within each group, the posterior palatal seal area's dimensional accuracy is the lowest.

Acknowledgements ; Not Applicable {N/A}

Ethics approval and consent to participate ; N/A

Consent for publication; N/A

Availability of data and materials; The datasets used and/or analysed during the current study available from the corresponding author on reasonable request. Also all data generated or analysed during this study are included in this published article [and its supplementary information files].

Competing interests; The authors declare that they have no competing interests.

Funding; This study did not receive any grant from funding agencies in the public, commercial, or not-for-profit sectors.

Patient consent statement

Patient consent not applicable. No patients were treated for this work.

Data availability statement

The datasets used and/or analyzed during the current study available from the corresponding author on reasonable request.

Ethical approval statement

Not applicable.

Authorship contribution statement

Mohamed A. Helal: Conceptualization, Writing – original draft, Writing – review & editing. Ahmed A. Zeidan: Conceptualization, Writing – original draft, Writing – review & editing.

Declaration of Competing Interest

The authors declare that they have no conflict of interest.

Funding statement

This research did not receive any funding.

Darvell BW, Clark RK. The physical mechanisms of complete denture retention. Br Dent J. 2000;189(5):248–52.
Sykora O, Sutow EJ. Posterior palatal seal adaptation: Influence of processing technique, palate shape and immersion. J Oral Rehabil. 1993;20(1):19–31.
Gharechahi J, Asadzadeh N, Shahabian F, Gharechahi M. Dimensional changes of acrylic resin denture bases: Conventional versus injection-molding technique. J Dent (Tehran). 2014;11(4):398–405.
Lee S, Hong SJ, Paek J, Pae A, Kwon KR, Noh K. Comparing accuracy of denture bases fabricated by injection molding, CAD/CAM milling, and rapid prototyping method. J Adv Prosthodont. 2019;11(1):55–64.
Steinmassl O, Dumfahrt H, Grunert I, Steinmassl PA. CAD/CAM produces dentures with improved fit. Clin Oral Investig. 2018;22(8):2829–35.
Helal MA, Abd Elrahim RA, Zeidan AA. Comparison of Dimensional Changes Between CAD-CAM Milled Complete Denture Bases and 3D Printed Complete Denture Bases: An In Vitro Study. J Prosthodont. 2022;PMID:35524633. https://doi.org/10.1111/jopr.13538.
Kalberer N, Mehl A, Schimmel M, Müller F, Srinivasan M. CAD-CAM milled versus rapidly prototyped (3-D-printed) complete dentures: An in vitro evaluation of trueness. J Prosthet Dent. 2019;121(4):637–43.
Faul F, Erdfelder E, Buchner A, Lang AG. Statistical power analyses using G*Power 3.1: Tests for correlation and regression analyses. Behav Res Methods. 2009;41(4):1149–60.
Jayaraj A, Jayakrishnan SS, Shetty KP, Nillan K, Shetty RR, Govind SL. 3-D printing in dentistry: A new dimension of vision.
Goodacre BJ, Goodacre CJ, Baba NZ, Kattadiyil MT. Comparison of denture base adaptation between CAD-CAM and conventional fabrication techniques. J Prosthet Dent. 2016;116(2):249–56.
Al-Dwairi ZN, Tahboub KY, Baba NZ, Goodacre CJ. A comparison of the flexural and impact strengths and flexural modulus of CAD/CAM and conventional heat‐cured polymethyl methacrylate (PMMA). J Prosthodont. 2020;29(4):341–9.
Bidra AS, Taylor TD, Agar JR. Computer-aided technology for fabricating complete dentures: Systematic review of historical background, current status, and future perspectives. J Prosthet Dent. 2013;109(6):361–6.
Infante L, Yilmaz B, McGlumphy E, Finger I. Fabricating complete dentures with CAD/CAM technology. J Prosthet Dent. 2014;111(5):351–5.
Han W, Li Y, Zhang Y, Lv Y, Zhang Y, Hu P, Liu H, Ma Z, Shen Y. Design and fabrication of complete dentures using CAD/CAM technology. Medicine. 2017;96(1):e5435.
Jeong YG, Lee WS, Lee KB. Accuracy evaluation of dental models manufactured by CAD/CAM milling method and 3-D printing method. J Adv Prosthodont. 2018;10(3):245–51.
van Noort R. The future of dental devices is digital. Dent Mater. 2012;28(1):3–12.
Torabi K, Farjood E, Hamedani S. Rapid prototyping technologies and their applications in prosthodontics, a review of literature. J Dent (Shiraz). 2015;16(1):1–9.
Kim WT. Accuracy of dental models fabricated by CAD/CAM milling method and 3-D printing method. J Oral Res. 2018;7(4):127–33.
Yau HT, Yang TJ, Lin YK. Comparison of 3-D printing and 5-axis milling for the production of dental e-models from intra-oral scanning. Comput Aid Des Appl. 2016;13(1):32–8.
Zaharia C, Gabor A-G, Gavrilovici A, Stan AT, Idorasi L, Sinescu C, et al. Digital dentistry—3-D printing applications. J Intern Med. 2017;2(1):50–3.
Hsu CY, Yang TC, Wang TM, Lin LD. Effects of fabrication techniques on denture base adaptation: An in vitro study. J Prosthet Dent. 2020;124(6):740–7.
Helal MA, Fadl-Alah A, Baraka YM, Gad MM, Emam AM. In-vitro Comparative Evaluation for the Surface Properties and Impact Strength of CAD/CAM Milled, 3D Printed, and Polyamide Denture Base Resins. J Int Soc Prev Community Dent. 2022;12(1):126–131; https://doi.org10.4103/jispcd.JISPCD_293_21.
Al-Dwairi ZN, Tahboub KY, Baba NZ, Goodacre CJ, Özcan M. A comparison of the surface properties of CAD/CAM and conventional polymethylmethacrylate (PMMA). J Prosthodont. 2019;28(4):452–7. https://doi.org/10.1111/jopr.13033.
Prpić V, Schauperl Z, Ćatić A, Dulčić N, Čimić S. Comparison of mechanical properties of 3Dprinted, CAD/CAM, and conventional denture base materials. J Prosthodont. 2020;29(6):524–8. https://doi.org/10.1111/jopr.13175.
Degirmenci K, HayatiM,Sabak C. Effect of different denture base cleansers on surface roughness of heat polymerised acrylic materials with different curing process. OdovtosInt J Dent Sc. 2020;22(3):145–53. http://doi.org/10.15517/ijds.2020.41900.
Ozyilmaz OY, Akin C. Effect of cleansers on denture base resins’ structural properties. J Appl BiomaterFunct Mater. 2019;17(1):2280800019827797. https://doi.org/10.1177/2280800019827797.
SrinivasanM CY, Mehl A, Gjengedal H, Muller F, Schimmel M. CAD/CAM milled removable complete dentures: an in vitro evaluation of trueness. Clin Oral Investig. 2016;21(6):2007–19. https://doi.org/10.1007/s00784-016-1989-7.

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Evaluation of The Effect of Thermocycling on The Trueness And The Precision of Digital Fabricated Complete Denture Bases

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INTRODUCTION

MATERIALS AND METHODS

Trueness evaluation

Precision evaluation

Thermocycling:

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