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A Survey on the Perception of the Cause of Failure of Dental Prosthesis Manufacture by Dental Technicians
Int J Clin Prev Dent 2021;17(1):12-20
Published online March 31, 2021;  https://doi.org/10.15236/ijcpd.2021.17.1.12
© 2021 International Journal of Clinical Preventive Dentistry.

Shin Geun Oh, Kyungsook Hwang, Chungjae Lee

Department of Dental Technology and Science, Shinhan University, Uijeongbu, Korea
Correspondence to: Chungjae Lee
E-mail: best8463@hanmail.net
https://orcid.org/0000-0001-5648-0830
Received March 7, 2021; Revised March 20, 2021; Accepted March 26, 2021.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Objective: When the patient visits the dentist to install the final dental prosthesis after treatment, the final dental prosthesis if it does not fit, the patient’s satisfaction will sharply drop if the patient’s hospitalization is requested. The remanufacturing of such a dental prosthesis reduces both patient satisfaction and causes manpower, time, and economic losses. Therefore, I would like to analyze the cause of the remanufacturing of dental prosthesis, centering on dental technicians who manufacture most of the dental prosthesis through questionnaires and identify a direction in which both patients and suppliers can be satisfied.
Methods: For this study, 193 dental technicians working in Seoul and Gyeonggi-do were randomly selected. The general characteristics of the study subjects were identified, and the cause and improvement plan for the remanufacturing of the dental prosthesis were identified.
Results: The cause of the remanufacturing of dental prosthesis as per the general characteristics of dental technicians was analyzed using one-way analysis of variance and Pearson’s correlation coefficient. For manufacturing the dental prosthesis, 48% of the subjects were ‘mistakes or lack of skills by the manufacturer in the laboratory’, 25% of them were ‘deformation of an impression or material’, and ‘inaccurate information provided by dentists’; it appeared in the order of 20%.
Conclusion: Because the causes of remanufacturing of dental prosthesis are not limited to dental technicians, but are diverse in the area where dental health professionals are engaged, all dental health care professionals reduce the remanufacturing of dental prosthesis and promote smooth communication such that patients can be satisfied.
Keywords : remanufacturing, medical satisfaction, dental prosthesis, medical communication
Introduction

It is necessary to improve the quality of health care services and the interior for those facilities to hold the lead during unlimited competition of healthcare facilities in South Korea because of the ever-increasing number of dentists, oversupply of physician assistants, the incorporation of healthcare organizations, and the introduction of private health insurance [1]. Moreover, it is necessary to make an effort to increase patient satisfaction such that they can continue to visit the facilities. Among the methods to improve patient satisfaction, easing discomfort in a patient’s mouth affects patient satisfaction the most [1]. However, when the patient visits a dental clinic to have the final dental prosthesis mounted on their teeth after treatment, if they are required to revisit the clinic because it does not fit well, patient satisfaction will drastically drop [2]. Such remanufacturing of dental prostheses does reduce not only patient satisfaction but also causes human resources, time, and economic losses [2]. Therefore, remanufacturing dental prostheses reduces patient satisfaction and can cause loss of time and human resources for dentists and staff in the clinics and patients’ expenses to revisit the clinic. This study aims to identify a direction that both patients and suppliers can be satisfied and to suggest primary data on the remanufacture of dental prostheses to improve the satisfaction of patients visiting dental clinics and the quality of healthcare services by analyzing the causes of failure in manufacturing dental prostheses and ways to improve it through a survey on dental technicians who manufacture most dental prostheses.

Materials and Methods

1. Subjects

In this study, 193 dental technicians were randomly selected in Seoul, accounting for 29.1% of the total ratio, and in Gyeonggi province, accounting for 14.4% of the total ratio, out of 10,351 dental technicians nationwide. A cross-sectional study was performed with a self-administered questionnaire filled by dental technicians. Naver Form was used to receive the data. The questionnaire was distributed for November 2020, and 193 responses were received. A total of 162 questionnaires were analyzed except for 31, which had many items with no answer.

2. Questionnaire

A tool of Lee et al. [3], where a study was conducted using a self-produced tool among the previous studies on remanufacturing of dental prostheses, was used for the survey. The study data of Huh [4], Cho [5], and Huh and Shim [6] were referred to for questions about detailed technical parts. Table 1 shows the contents of the questionnaire. Those are as follows: 5 items about general information of dental technicians (sex, age, work experience, the highest education level, and working department), 5 items about dental technicians’ remanufacturing of dental prostheses (remanufacturing causes, internal matters in dental laboratories when remanufacturing happens, internal matters in dental clinics when remanufacturing happens, whether to communicate between a dental clinic and a dental laboratory when remanufacturing prostheses, and measures to reduce remanufacturing of dental prostheses), and 1 item each about the average number of monthly produced prostheses and remanufactured prostheses (used the average value gained from subjective questionnaires).

Table 1 . General information about dental technicians

ItemDivisionResponse
SexMale113 (69.0)
Female49 (31.0)
Age20s73 (45.0)
30s47 (29.0)
40s39 (24.0)
50s2 (1.0)
60s1 (1.0)
Work experience (yr)<1078 (48.0)
10-1519 (12.0)
15-2026 (16.0)
20-2537 (23.0)
>252 (1.0)
The highest education levelVocational college degree90 (56.0)
Bachelor’s degree69 (42.0)
Post-graduate degree3 (2.0)
Working departmentCrown department39 (24.0)
Denture department41 (25.0)
Ceramic department43 (26.0)
CAD/CAM department36 (23.0)
Others3 (2.0)
Total162 (100.0)

Values are presented as number (%). CAD/CAM: Computer aided design/Computer aided manufacturing.



3. Statistical analysis

Statistical analysis was performed using IBM SPSS Statistics for ver. 22.0 (IBM Co., Armonk, NY, USA). Pear-son’s chi-squared test was used to compare each general matter as per the requested manufacturing methods of the pro-sthesis. A one-way analysis of variance was performed using Duncan’s post-hoc test to analyze the association of the remanufacturing rate of dental prostheses.

Results

1. General characteristics of subjects

Table 1 shows the general information of subjects. In terms of the sex of dental technicians, males accounted for the majority, accounting for 69% of the total, while females accounted for 31%. The age of dental technicians was the highest at 45% in their 20s. Work experience was 48% for <10 years, 23% for 20-25 years, and 1% for >25 years. The highest education level, a vocational college degree was the most at 56%, bachelor’s degree at 42%, and post-graduate degree at 2%.

2. Work-related matters of subjects

Table 2 shows the average number of manufactured prostheses by each department for a month, the average number of remanufactured prostheses for a month, and the remanu-facturing rate. A Crown department manufactured 159.7 prostheses for a month on average and remanufactured 12.2 prostheses, thus showing a remanufacturing rate of 8.58%. A Denture department manufactured 119.9 prostheses on average, thus showing 6.04% as the remanufacturing rate, while a Ceramic department manufactured 152.7 prostheses and remanufactured 10.1. A Computer aided design/Computer aided manufacturing (CAD/CAM) department manufactured an average of 173.3 prostheses for a month, with the remanu-facturing rate at 6.5%.

Table 2 . The average number of manufactured and remanufactured prostheses by each department for a month and the remanufacturing rate

ItemNumber of peopleThe average number of manufactured prostheses The average number of remanufactured prostheses Remanufacturing rate*
Crown39159.7±40.112.2±16.48.58±12.06
Denture41119.9±18.87.4±5.076.04±3.8
Ceramic43152.7±41.410.1±6.26.86±3.78
CAD/CAM36173.3±157.19.9±4.66.5±2.9
Others3149.3±26.64.3±2.082.9±1.4

Values are presented as mean±standard deviation or rate(%)± standard deviation. CAD/CAM: Computer aided design/Computer aided manufacturing. *The number of remanufactured prostheses by each department for a month/ The number of manufactured prostheses by each department for a month*100.



Table 3 shows the correlation between the number of prostheses manufactured by each department for a month in dental laboratories and the remanufacturing rate. The Crown department showed a correlation between the number of prostheses manufactured for a month and the remanufacturing rate, and the remanufacturing rate decreased as the number of the manufactured prostheses increased. For Denture and Ceramic departments, there was no correlation between the number of manufactured prostheses for a month and the remanufacturing rate. The CAD/CAM department did not also show a correlation with remanufacturing rates.

Table 3 . The number of prostheses manufactured by each part in dental laboratories for a month and the remanufacturing rate

Crown RDenture RCeramic RCAD/CAM ROthers R
Crown−0.321*
Denture−0.259
Ceramic−0.212
CAD/CAM−0.328
Others0.001

R: Remanufactured prostheses, CAD/CAM: Computer aided design/ Computer aided manufacturing. By Pearson’s chi-squared test, *p< 0.05.



3. Survey on remanufacturing of dental prostheses

1) Causes of remanufacturing dental prostheses

Table 4 lists the responses to the causes of remanufacturing dental prostheses. ‘Mistakes or lack of technique by the makers in the laboratory’ was the highest percentage of the reasons for remanufacturing, 48%. ‘Deformation of impression bodies or materials’ accounted for 25%, followed by ‘incorrect information provided by the dental clinic’ by 20%, ‘deformation of the patient’s oral environment’ by 5%, ‘damaged prosthesis during delivery’ by 1%, and ‘others’ by 1%.

Table 4 . The responses to the causes of remanufacturing dental prostheses

ItemResponse
Mistakes or lack of technique by the makers in the laboratory78 (48.0)
Deformation of impression bodies or materials40 (25.0)
Incorrect information provided by the dental clinic34 (20.0)
Deformation of the patient’s oral environment8 (5.0)
Damaged prosthesis during delivery1 (1.0)
Others1 (1.0)

Values are presented as number (%).



Among the ‘incorrect information provided by the dental clinic,’ one of the causes of remanufacturing dental prostheses, 61% were ‘related to dentists,’ 30% were ‘related to dental assistants,’ 9% were ‘related to communication between a dental clinic and a dental laboratory,’ and 0% was ‘Others’ (Table 5).

Table 5 . The responses to incorrect information provided by the dental clinic

ItemResponse
Related to dentists21 (61.0)
Related to dental assistants10 (30.0)
Relatedto communication between a dental clinic and a dental laboratory3 (9.0)
Others0 (0.0)

Values are presented as number (%).



Among the ‘mistakes or lack of technique by the makers in the laboratory,’ 60% were ‘error in the judgment of the dental technicians,’ 17% were ‘lack of prosthesis manufacturing time,’ 16% were ‘lack of experience,’ and 7% in ‘Others’ (Table 6).

Table 6 . The responses to mistakes or lack of technique by the makers in the laboratory

ItemResponse
Lack of experience9 (16.0)
Error in the judgment of the dental technicians’34 (60.0)
Lack of prosthesis manufacturing time10 (17.0)
Others4 (7.0)

Values are presented as number (%).



Tables 7 show the response ranking by each department of remanufacturing causes of dental prostheses is shown in. The Crown department’s major cause of remanufacturing was ‘occlusion’ of 33%, followed by ‘fitting’ at 5%. The major remanufacturing cause in the Denture department was ‘inade-quate margin’ at 42%, while the Ceramic department showed 43% in ‘shape (appearance)’ as the primary cause. In the CAD/CAM department, the major remanufacturing cause was ‘design errors’ of 50%, followed by ‘error in model scanner overlay’ of 9%.

Table 7 . The responses by the department of remanufacturing dental prostheses (Crown, Ceramic, Denture, CAD/CAM and others)

ItemCrownCeramicDentureCAD/CAMOthers
Shape (appearance)3 (14.0)10 (43.0)
Maintenance, support2 (10.0)2 (9.0)
Occlusion7 (33.0)3 (13.0)
Margin5 (23.0)3 (13.0)
Contact2 (10.0)2 (9.0)
Fitting1 (5.0)1 (4.0)1 (100.0)
Others1 (5.0)2 (9.0)
Overextended margin6 (28.0)
Inadequate margin9 (42.0)
Polymerization shrinkage of the resin2 (10.0)
Abnormal shape of denture base2 (10.0)
Others2 (10.0)
Design errors6 (50.0)
Error in model scanner overlay1 (9.0)
Error in setting processing directions of a milling bar3 (25.0)
Diameter and condition faulty of a milling bar2 (16.0)
Fitting error0 (0.0)
Others0 (0.0)

Values are presented as number (%). CAD/CAM: Computer aided design/Computer aided manufacturing.



2) Communication between the dental clinic and the dental laboratory when remanufacturing a dental prosthesis happens

Note that 96% of subjects responded that the dental laboratory communicates with the dental clinic when remanu-facturing occurs, 3% responded that they do not, and 1% responded as others (Table 8).

Table 8 . Whether to communicate between the dental clinic and the dental laboratory when remanufacturing dental prostheses

ItemResponse
Yes156 (96.0)
No5 (3.0)
Others1 (1.0)
Total162 (100.0)

Values are presented as number (%).



3) How to reduce remanufacturing of dental prostheses

Table 9 shows the response results on how to reduce remanufacturing of dental prostheses. ‘Smooth communication between a dentist, a dental hygienist, and a dental technician’ showed the highest rate of responses, accounting for 31%, followed by ‘technique improvement of dental technicians’ at 26%, ‘sufficient time for manufacturing prostheses’ at 17%, ‘improvement in practical abilities of the dental clinic system’ at 16%, and ‘good quality of dental materials’ at 10%.

Table 9 . How to reduce remanufacturing of dental prostheses

ItemResponse
Smooth communication between a dentist, a dental hygienist, and a dental technician51 (31.0)
Sufficient time for manufacturing prostheses28 (17.0)
Good quality of dental materials16 (10.0)
Improvement in practical abilities of the dental clinic system26 (16.0)
Technique improvement of dental technicians’41 (26.0)

Values are presented as number (%).



4) Association analysis between general information of dental technicians and the remanufacturing rate

As per the general information of dental technicians, each part’s remanufacturing rates are shown in Table 10. For males, the Crown department’s remanufacturing rate was the highest with 9%, followed by the Ceramic department with 8.6%, the CAD/CAM department with 6.2%, the Denture department with 6.1%, and others with 2.1%. For females, the CAD/DAM department was the highest remanufacturing rate with 12.5%, followed by the Ceramic department with 6.7%, the Crown department with 4.5%, others with 4.4%, and the Denture department with 2.5%. In terms of the remanufacturing rate depending on work experience, when work experience was less than 10 years, the remanufacturing rate of the Crown department was the highest at 12.3%. Furthermore, when work experience was >15 years and <20 years, the remanufacturing rate of Denture department was the highest at 6.4%, and the Crown department was at 3.6%. When work experience was >20 years and <25 years, the remanufacturing rate of the CAD/CAM department was the highest at 5.7%, and when work experience was >25 years, the remanufacturing rate of the Crown department was at 1.1%, and the Denture department was at 1.0%.

Table 10 . The remanufacturing rates of each department according to general information of dental technicians

Crown RDenture RCeramic RCAD/CAM ROthers R





ResponseM±SDResponseM±SDResponseM±SDResponseM±SDResponseM±SD
Sex
Male359.0±12.6406.1±3.828.6±6.5346.2±2.222.1±0.8
Female44.5±0.812.5±0.0416.7±3.7212.5±7.614.4±0.0
p-value*0.3670.0000.2830.0000.000
Age
20s2112.7±15.3158.8±3.1248.6±4.1137.7±4.323.5±1.1
30s163.9±1.366.4±3.2184.7±1.456.6±1.511.5±0.0
40s12.2±0.0183.8±3.013.3±0.0185.7±1.6
50s11.1±0.015.2±0.0
60s11.0±0.0
p-value**0.1360.0010.0010.1930.380
Work experience
less than 10 years2212.3±15.0168.6±3.2258.6±4.0157.4±4.123.5±1.1
10-15 years94.1±1.333.9±1.825.8±1.137.5±0.6
15-20 years63.6±1.656.4±3.8154.2±0.811.5±0.0
20-25 years12.2±0.0164.0±3.213.3±0.0185.7±1.6
More than 25 years11.1±0.011.0±0.0
p-value**0.2920.0020.0020.2470.380
The highest education level
Vocational college degree225.7±4.1264.7±3.3194.3±1.0206.5±3.232.9±0.0
Bachelor’s degree1612.8±17.6148.7±3.2248.8±3.9156.8±2.5
Post-graduate degree12.3±0.011.6±0.012.7±0.0
p-value**0.1750.0020.0000.409

R: Remanufactured prostheses, M±SD: mean±standard deviation. *Calculated by an independent samples t test. **Calculated by a one-way analysis of variance.



Table 11 shows the remanufacturing rates of each part according to the causes of remanufacturing dental prostheses. In ‘mistakes or lack of technique by the makers in the laboratory,’ the remanufacturing rates were shown to be 12.5% in the Crown department, 8.5% in the Denture department, 8.0% in the Ceramic department, 8.1% in the CAD/CAM department, and 1.5% in others. In ‘deformation of impression bodies or materials,’ the rates were 3.6% in the Crown department, 3.4% in the Denture department, 5.1% in the Ceramic department, 5.6% in the CAD/CAM department, and 4.4% in others. In ‘incorrect information provided by the dental clinic,’ the rates were 4.0% in the Crown department, 4.6% in the Denture department, 9.6% in the Ceramic department, 5.9% in the CAD/CAM department, and 2.7% in others. In ‘de-formation of the patient’s oral environment,’ the remanufacturing rates were 5.5% in the Crown department, 1.7% in the Denture department, and 2.5% in the Ceramic department. In ‘damaged prostheses during delivery,’ the Ceramic department showed the remanufacturing rate at 5.1%. For ‘others,’ the remanufacturing rate of the CAD/CAM department was 2.0%.

Table 11 . The remanufacturing rates of each department as per the causes of remanufacturing dental prostheses

Crown RDenture RCeramic RCAD/CAM ROthers R





ResponseM±SDResponseM±SDResponseM±SDResponseM±SDResponseM±SD
Mistakes or lack of technique by the makers in the laboratory2112.5±15.4218.5±3.2238.0±3.6128.1±4.111.5±0.0
p-value*0.1770.0770.0310.063
Deformation of impression bodies or materials123.6±1.0113.4±1.9145.1±2.425.6±1.414.4±0.0
p-value*0.3080.0010.0120.087
Incorrect information provided by the dental clinic44.0±2.754.6±2.939.6±6.7215.9±1.612.7±0.0
p-value*0.1240.0020.0270.023
Deformation of the patient’s oral environment25.5±2.041.7±0.922.5±1.1
p-value*0.0000.0000.033
Damaged prostheses during delivery13.6±0.0
p-value*0.000
Others12.0±0.0
p-value*

R: Remanufactured prostheses, M±SD: mean±standard deviation. *Calculated by analysis of variance.



Table 12 shows the remanufacturing rates of each department according to the internal causes in the dental clinic. In ‘related to dentists,’ the Crown department’s remanufacturing rate was shown to be 1.6%, the Denture department was 3.9%, and the CAD/CAM department’s rate was 5.9%. In ‘related to dental assistants,’ the Crown department showed the rate at 6.4%, the Denture department at 2.6%, and the Ceramic department at 5.8%. In ‘related to communication between a dental clinic and a dental laboratory,’ the Ceramic department showed the remanufacturing rate at 17.3%, and the CAD/CAM department showed 7.0%. For ‘others,’ the remanufacturing rate of 2.7% was shown in the other de-partment.

Table 12 . The remanufacturing rates of each part according to internal causes in the dental clinics

Crown RDenture RCeramic RCAD/CAM ROthers R





ResponseM±SDResponseM±SDResponseM±SDResponseM±SDResponseM±SD
Related to dentists21.6±0.853.9±3.6145.9±1.5
p-value*0.0160.7680.556
Related to dental assistants26.4±0.212.6±0.025.8±1.152.0±0.9
p-value*0.0290.0790.607
Related to communication between a dental clinic anda dental laboratory117.3±0.027.0±1.6
p-value*0.361
Others12.7±0.0
p-value*

R: Remanufactured prostheses, M±SD: mean±standard deviation. *Calculated by analysis of variance.



Table 13 shows the remanufacturing rates of each part according to opinion exchange when manufacturing prostheses. In ‘mainly use prosthesis manufacturing requests only,’ the Crown department’s remanufacturing rate was 11.9%, and the CAD/CAM department showed 7.2%. In ‘exchange opinions frequently via telephone,’ the Crown department showed the rate at 4.9%, the CAD/CAM department at 5.6%, and others at 2.9%. In ‘receive prosthesis manufacturing requests, identifying a patient’s condition directly in a dental clinic,’ the Crown department showed the rate of 3.0%, the Denture department of 3.5%, the Ceramic department of 3.9%, and the CAD/CAM department of 6.2%. In ‘exchange opinions with dental assistants,’ the Crown department’s rate was 7.2%, the Denture department was 7.3%, and the Ceramic department was 5.9%.

Table 13 . The remanufacturing rates of each part according to the ways of exchanging opinions

Crown RDenture RCeramic RCAD/CAM ROthers R
ResponseM±SDResponseM±SDResponseM±SDResponseM±SDResponseM±SD
Mainly use prosthesis manufacturing requests only1511.9±18.5237.1±4.0217.3±3.0187.2±3.512.7±0.0
p-value*0.6910.0330.0040.378
Exchange opinions frequently via telephone74.9±3.473.2±1.675.5±4.095.6±1.722.9±2.0
p-value*0.3300.0570.0590.2360.953
Receive prosthesis manufacturing requests, identifying a patient’s condition directly in a dental clinic23.0±0.953.5±2.333.9±0.796.2±2.6
p-value*0.3030.0580.0420.185
Exchange opinions with dental assistants117.2±4.667.3±3.6105.9±3.4
p-value*0.4760.0410.012
No communication48.7±4.6215.3±2.8
p-value*0.5640.038

R: Remanufactured prostheses, M±SD: mean±standard deviation. *Calculated by analysis of variance.


Discussion

In this study, the causes of remanufacturing dental prostheses were analyzed with the necessity of it, predicated on the occurrence of loss of time and money in dental laboratories that comes with it, and in terms of dental clinics, significant financial loss to dental practice management because of decreased patient satisfaction, waste of human resources such as dentists and dental assistants, and expense resulting from patients’ revisiting clinics [2,7-8], through a questionnaire survey with the additional CAD/CAM department that had not been investigated in the previous studies. Compared to the previous study by Lee et al. [3], for the cause of remanufacturing dental prostheses, ‘deformation of impression bodies and materials’ was the highest in the study of Lee et al. [3], while ‘mistakes or lack of technique by the makers in the laboratory’ was the highest response in this study. It is considered that because 45% of the subjects in this study were in their twenties, who may be lack practical skills, while Lee’s study was conducted on directors of dental laboratories.

This study has demonstrated that the causes of remanu-facturing dental prostheses varied depending on the fields where dental healthcare personnel belonged, including mistakes or lack of technique by the makers in the laboratory,’ ‘deformation of impression bodies or materials,’ and ‘incor-rect information provided by the dental clinic.’ Therefore, it can support the results that the remanufacturing rate of dental prostheses should be reduced by collecting diverse opinions based on smooth communication between dental healthcare personnel as the cause of remanufacturing dental prostheses is not a single problem.

Conclusion

This study conducted a survey on dental technicians about remanufacturing of dental prostheses to identify ways to satisfy both patients and suppliers by analyzing the causes of remanufacturing dental prostheses to improve patient satis-faction in dental clinics. Moreover, 193 subjects were randomly selected among dental technicians working in Seoul and Gyeonggi province to perform the survey, and the responses from a total of 193 people were collected from November 5th, 2020, to November 27th, 2020. Except for 31 cases with many no-answers, a total of 162 questionnaires were analyzed to obtain the results of the study as follows.

1.For general characteristics of the study subjects, males accounted for the majority, accounting for 69%, and in terms of age, 45% was in their 20s, 29% in their 30s, 24% in their 40s, and 1% in their 50s and 60s. For work experience, 48% of the subjects have worked for less than 10 years, 12% for more than 10 years and less than 15 years, 16% for more than 15 less than 20 years, 23% for more than 20 less than 25 years, and 1% for more than 25 years. Regarding the highest education level, 56% were vocational college degree holders, 42% were Bachelor’s degree holders, and 2% were post-graduate degree holders.

2.The responses to the causes of remanufacturing dental prostheses demonstrated 48% in ‘mistakes or lack of technique by the makers in the laboratory’ which was the highest, 25% in ‘deformation of impression bodies or materials,’ 20% in ‘incorrect information provided by the dental clinic,’ 5% in ‘deformation of the patient’s oral environment,’ and 1% each in ‘damaged prosthesis during delivery’ and ‘others.’

3.In terms of the correlation between the number of dental prostheses manufactured in dental laboratories for a month and the remanufacturing rate of dental prostheses, only the Crown department demonstrated the negative correlation, which indicated that the remanufacturing rate decreased significantly as the number of dental prostheses manufactured by the Crown department increased.

4.Regarding the causes of remanufacturing dental prostheses in each part, the Crown department demonstrated the highest rate in ‘occlusion’ at 33%, and ‘inadequate margin’ was shown to be 42% in the Denture depart-ment. ‘Shape (appearance)’ was selected to be 43% in the Ceramic department, ‘design errors’ in the CAD/ CAM department was 50%, and ‘fitting’ in the other department was 100%.

5.To reduce remanufacturing of dental prostheses, ‘smoo-th communication between dentists-dental hygienists- dental technicians’ was first ranked at 31%, and the second-highest was ‘technique improvement of dental technicians’ at 26%. The third was ‘sufficient time for manufacturing a prosthesis’ at 17%, the fourth was ‘improvement in the practical ability of dental clinic system’ at 16%, and the fifth was ‘good quality of dental materials’ at 10%.

These results demonstrated that the causes of remanu-facturing dental prostheses vary depending on dental healthcare personnel’s fields, including ‘mistakes or lack of technique by the makers in the laboratory,’ ‘deformation of impression bodies or materials,’ and ‘incorrect information provided by the dental clinic.’ It is necessary to provide satisfying healthcare services to patients to improve patient satisfaction, reducing remanufacturing of dental prostheses by collecting diverse opinions based on smooth communication between dental healthcare personnel, which was the most possible approach with the highest rate to reduce remanufacturing.

Conflict of Interest

No potential conflict of interest relevant to this article was reported.

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