FUTURE IS NOW: IMPRESSIONS AND DIGITAL STORAGE

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Aurimas Čiočys

5th year, group 14

FUTURE IS NOW: IMPRESSIONS AND DIGITAL

STORAGE

Master’s Thesis

Supervisor Dr. Gediminas Skirbutis

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FINAL MASTER‘S THESIS IS CONDUCTED AT THE DEPARTMENT OF PROSTHODONTICS

STATEMENT OF THESIS ORIGINALITY

I confirm that the submitted Final Master‘s Thesis Future is Now: impressions and digital storage 1. Is done by myself.

2. Has not been used at another university in Lithuania or abroad.

3. I did not used any additional sources that are not listed in the Thesis, and I provide a complete list of references.

I confirm by e-mail, and the work will be signed after the end of the quarantine and emergency situation due to the COVID-19 pandemic in the republic of Lithuania.

2020/04/28 Aurimas Čiočys (signature)

CONCLUSION OF FINAL MASTER‘S THESIS ACADEMIC SUPERVISOR

ON THE DEFENSE OF THE THESIS

2020/04/28 Dr. Gediminas Skirbutis (signature)

FINAL MASTER‘S THESIS IS APPROVED AT THE DEPARTMENT

(date of approval) (name of the Department and full name of the Head of the Department) (signature)

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Final Master‘s Thesis reviewer

(full name) (signature)

Evaluation of Final Master‘s Thesis Defense Board:

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LITHUANIAN UNIVERSITY OF HEALTH SCIENCES MEDICAL ACADEMY

FACULTY OF ODONTOLOGY DEPARTMENT OF PROSTHODONTICS

FUTURE IS NOW: IMPRESSIONS AND DIGITAL STORAGE Master’s thesis

The thesis was done by student: Supervisor:

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(signature) (signature)

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(name, surname, year, group) (degree, name, surname)

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(day/month/year) (day/month/year)

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EVALUATION TABLE OF CLINICAL-EXPERIMENTAL MASTER’S THESIS

Evaluation: ………..

Reviewer: ……….

(scientific degree, name and surname)

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FUTURE IS NOW: IMPRESSIONS AND DIGITAL STORAGE

SUMMARY

Aim. To compare Lithuanian University of Health Sciences (LUHS) and Vilnius University (VU) Odontology Faculty (OF) 4th and 5th year students’ understanding and knowledge of conventional and digital impressions and to evaluate attitudes towards digital impression storage.

Materials and methods. The study was approved by the Bioethics Centre of the LUHS (BEC-OF-43). A cross-sectional study was conducted among 4th and 5th year OF students at LUHS and VU in 2019-2020. 193 students from LUHS and 44 students form VU participated in the research. A self-administered Lithuanian and English questionnaire was used. Statistical data analysis was performed using SPSS 17 version. To establish a relationship between two variables Pearson Chi-Squared test (χ2) was used. The significance level was set to <0.05.

Results. The response rate was 85.8% for LUHS and 60.3% for VU 4th_{and 5}th_{year OF students.} Results have shown that VU OF students rated their experience of using conventional impressions in university practice more positively (p=0.022). 100% of respondents did not use digital impressions in university practice and the majority of both research groups were not introduced to an intraoral scanner (IOS) and their using technique in university. There was no difference in objective knowledge self-evaluation about digital and conventional impressions between LUHS and VU groups.

Conclusion. There is no difference between LUHS and VU OF students’ understanding and knowledge about conventional and digital impressions and their using technique. Both groups had a positive attitude towards digital impression storage.

Keywords: Dental Students, Dental Impression Technique, Dental Models, Knowledge, Attitude, Lithuania

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ABBREVIATIONS

LUHS: Lithuanian University of Health Sciences VU: Vilnius University

OF: Odontology faculty IOS: Intraoral scanner

CAD/CAM: Computer-aided design and computer-aided manufacturing SPSS: Statistical Package for the Social Sciences

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INTRODUCTION

One of the most important procedure requiring accuracy, handling technique and strictly followed protocol in prosthetic dentistry is impression taking. The negative imprint taken will determine the success of the final restoration.

In the early days, 1700s, for the creation of dental impression beeswax was used as it was reasonably soft material, easy to use and impression of the oral cavity could be visible on the impression tray which was a sculpted bone or carved wooden arch. In the mid-1800s the impression tray was adapted to fit the anatomical peculiarities of the oral cavity and a similar version of metal impression trays are used nowadays. In the 20th century there was a pivotal moment for dental impression materials and techniques. The protocol of producing an impression, creation of impression trays, the concept of functional impressions and advancement in impression materials highly increased the quality and understanding of the final dental prosthetic restorations [1]. Improvement and discovery of elastic materials: synthetic elastomers (polysulphides, silicones, polyethers) and hydrocolloids (agar and alginate), slowed down as the properties of those were sufficient. However, application technique, accuracy, dimensional stability, working time, patient acceptance and oral environmental acceptance is always improving [2]. There is no superior conventional impression material which will not have any limitations, that is why improvement in this field is always undergoing.

In the late 20th_{century, as the desktop computers were more popular and the availability of modern} computer technologies were greater, the invention of digital impressions occurred. Nowadays, in the 21st_{century with the use of the intraoral scanner, the oral cavity can be scanned and the reflected} image is shown on the computers’ screen. This image can be inspected at higher magnification and the mistakes or improvements of preparation surface or margins are easier spotted and corrected. Also, the reduction of clinical steps is noted as the time is saved because there is no tray selection, material preparation, disinfection of the impressions and physical technician time to pick up the impression and pour out the cast. With the use of software, the final restoration can be planned and then milled by the technician or even at the chairside [3]. Computer-aided design and computer-aided manufacturing (CAD/CAM) gained popularity as the accuracy, working time, manufacturing time and patient satisfaction is competitive to conventional impressions. In recent years, the popularity of IOS highly increased, but the gold standard of the procedure is still known as the conventional impression technique.

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12 Over the years, dental casts and impressions are stored and archived for future treatment and to follow up treatment progress. However, it takes a lot of space so the storage cabinets or designated space needs to be introduced in the dental laboratory or dental clinic, dental casts are fragile and storage of dental casts can be time and labour consuming. Digital impressions give us the possibility to store and archive impressions more efficiently as it will not take physical space and the search of those models are more efficient with the computer software. Orthodontists started storing casts of the patients’ for follow-up reasons such as treatment planning, following up the treatment progress and as examples for future treatment [4]. However, in the department of prosthodontics casts are used for prosthesis manufacturing and rarely kept after the treatment. Intraoral photographs are more used for following the treatment progress.

The null hypotheses for this research were that there is no difference between LUHS and VU 4th and 5th year OF students in case of knowledge of conventional and digital impressions and that dentistry students from LUHS and VU will have a positive attitude towards digital impressions and digital impression storage.

AIMS

1. Compare LUHS and VU OF 4th and 5th year students’ understanding and knowledge of conventional and digital impressions.

2. Evaluate LUHS and VU OF 4th and 5th year students’ attitudes towards digital impression storage.

OBJECTIVES

1. Create a detailed questionnaire about conventional impressions, digital impressions and digital impression storage in Lithuanian and English languages.

2. Distribute and collect the data about conventional impressions, digital impressions and digital impression storage among the LUHS and VU 4th_{and 5}th_{year odontology students.}

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1. REVIEW OF LITERATURE

1.1. Digitalization in dentistry field

In the 1990s, when computer-aided design and computer-aided manufacture (CAD/CAM) was firstly used, it seemed like a revolution in the dentistry field [5]. With the increased optimization and improvement of intraoral scanners during the past decade, digitalization in the dentistry field increasingly catches more attention of the dental professionals and students [6]. As the word

“digital” is more often mentioned in the field of dentistry and the digital technology is changing the clinical practice, the dental professionals and students need to think critically and choose the most advantageous method and material for their clinical practice [7]. In a cross-sectional survey, done in Switzerland, they found out that the age of the dentist and digitalization of the dental practice has a relationship - the younger the dentist and the more recent the dental clinic was opened, the higher the grade of digitalization was seen [8]. With the late adopters of digital dentistry, the attitudes towards the digitalization were different [9]. In this study attitudes of early adopters will be compared towards the digitalization in dentistry.

1.2. Conventional versus digital impressions

The technical development of IOS’ technical abilities, parameters, ease of usage and availability led to be closely compared to conventional impression materials and methods. The most compared value of digital versus conventional impressions is the accuracy of the impression and the final restoration. The inexperienced practitioners would think that digital impressions are superior in case of accuracy because of the precision of the IOS, their digital scanning capability and the overall advancement of digitalization in the world. Therefore the differentiation between the necessities of impression needs to be made: crowns, crowns on implants, short fixed dental prostheses or full-arch impressions. Digital impressions of crowns, crowns on implants, short fixed dental prostheses nowadays can be accepted as clinically the result is acceptable [10]. However, in full-arch impressions, the results were more accurate and in favor of conventional impressions [10]. Conventional impressions are still recommended for full-arch impressions despite the advancement of technology. In a study that compared three-dimensional models in vitro, the digital impression technique was less accurate than

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14 the conventional and the results showed that it did not meet the criteria of clinical acceptance [11]. In the 2019 study, where the latest models of IOS were used, 3Shape TRIOS (3Shape, Copenhagen, Denmark) and CEREC Omnicam (Dentsply, York, Pennsylvania, United States), the conclusion was made of achieving clinical satisfying accuracy and that the intraoral digital impressions can be used for three-dimensional gingival contour in the aesthetic zone [12]. There are no currently available data or reviews of the definitive advantageous accuracy data of digital impressions versus conventional. In 2020, the review was made about the intraoral scanning and the conventional impression techniques and it stated that the more clinical trials are needed to truly grasp the advantages and disadvantages of digital technique and their use in the clinical field [13]. More technological developments and advancements are needed for the superior accuracy of digital impressions over conventional to be the gold standard of the impression taking technique [14]. Despite the questioned accuracy of the digital impressions, the comfortability and acceptance of the patient are superior of the intraoral scanning compared to conventional impressions. With the lack of usage of leaking materials and clean working space, the digital impression method is more accepted by the patients than conventional impressions [14,15]. With the patients who have a gag reflex and anxiety of dental treatment, digital impressions with an IOS are the preferred choice of the impression taking method. The second main advantage of digital impression taking technique would be the time efficiency. The procedure of taking a digital dental model takes less time [16]. However, the time taken for a full protocol of impression taking is highly dependent on operators’ experience and type of IOS in use [17].

1.3. Student experience with digital impressions

As the time taken and the quality of the final digital impression depends on the experience of the operator [17], it is interesting to see what attitude towards the digital impressions and IOS students would have, having in mind the lack of experience. The study, conducted in Switzerland, as the first-time users, students had a 76% preference of IOS, twice less first-time spent using IOS and higher overall acceptability of digital impression technique compared to conventional impressions [18].

With the rise of the market for IOS, there is an increase in different brands of IOS. In the study which used 3Shape TRIOS Colour, True Definition (3M, St. Paul, Minneapolis, United States) and CEREC AC OmniCam scanning systems, the inexperienced final-year dental students had significantly dependent results on the scanning systems used. Despite the differences in the performance of IOS

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15 systems, students had a positive result of the digital impression technique and had a high likelihood of future usage of the digital intraoral scanning systems [19].

With the positive attitude of students towards the digital impression technique, dental schools need to implement the new curriculum according to the rapidly changing world of dental digitalization. Magnified digitally scanned preparation can reveal valuable information for the students such as the chamfer lines and surface of preparation. It can become a valuable tool for enhancing education [20].

1.4. Digital dental model storage

Storage of gypsum dental models causes issues such as the storage space, price of maintenance and accurate labeling. In a study, done in 2020, from 158 orthodontists, 78.48% of respondents stated that there are problems with storage space in clinics [21]. Archiving dental records are needed for future treatment planning, following the treatment progress or in case of trauma easier way to restore the tooth. With the digital dental model archive, the problem of space availability is removed as required digital space for the three-dimensional computerized model is about 300 KB [4]. An easier search of the models via computer and never-aging model is another advantage of the digital dental models. With the increased patient acceptance of intraoral scanners [15], production of digital models can be easily achieved and therefore can be stored and used for future purposes of the dental treatment such as following up the treatment plan, planning the future treatment and as well having the information of patients’ natural teeth: their anatomy, color and occlusion.

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2. MATERIALS AND METHODS

Ethical approval was obtained in 2019-11-20, from the LUHS Bioethics department. Reference number – BEC-OF-43 (ANNEX 1). Confidentiality of respondents was ensured as the questionnaire was completely anonymous and no personal data was collected including name, surname and signature.

The questionnaire was made in two languages: Lithuanian and English. The questionnaire consisted of four parts. The first part was about the student experience and knowledge in regard to conventional and digital impression techniques. The second part was about comparing conventional and digital impression techniques. The third part was about advantages, challenges and the future of conventional and digital impression techniques. The last part was about the storage of dental models.

A cross-sectional study was conducted from December 2019 to March 2020, in LUHS, Kaunas and VU, Vilnius. The requirement to participate in the questionnaire was that participants must be 4th or 5th year OF students currently enrolled in LUHS and VU odontology program in Lithuanian or English language. Exclusion criteria were set to be non-odontology faculty students in LUHS and VU; 1st_{, 2}nd_{and 3}rd_{year odontology students.}

According to the data received, in November 2019, there were 225 4th_{and 5}th_{year odontology} students currently enrolled in LUHS and 73 4th_{and 5}th_{year odontology students in VU.}

Physical copies of the questionnaire were distributed to all 4th_{and 5}th_{year odontology students in} LUHS before, during or after the prosthodontics clinical works in the university. VU OF students received identical questionnaires but in the digital form. Digital questionnaires were uploaded to

www.apklausa.lt .

The data obtained from physical copies were entered into Statistical Package for the Social Sciences (SPSS) program, version 17. Digital questionnaire copies were transferred from the Excel data sheet to the SPSS program. Data was presented by frequency tables as percentages (%) and bar charts. Pearson Chi-Squared test (χ2) was used to compare the relationship between two categories (LUHS students and VU students). The significance level was set at p < 0.05.

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3. RESULTS

3.1. Student experience and knowledge

The questionnaires were answered by a total of 237 students from both universities. 193 students from LUHS and 44 students from VU. The response rate of LUHS OF students was 85.8% which gives a margin of error of 3% with 95% confidence level; the response rate of VU OF students was 60.3% which gives the margin of error of 9% with 95% confidence level.

Table 1. Categories of respondents

University Study year Course type Number (N) Total number (N)

LUHS 4 Lithuanian 64 193 4 International 19 5 Lithuanian 88 5 International 22 VU 4 Lithuanian 15 44 4 International 5 5 Lithuanian 18 5 International 6

193 (100%) students from LUHS and 44 (100%) students from VU used conventional impressions in university practice. Within the LUHS OF students experience ratings while using conventional impressions during university practice were: 3.1% bad, 3.1% poor, 42.5% average, 31.6% satisfactory and 19.7% good (Fig 1.). Within the VU OF students: 0% bad, 9.1% poor, 20.5% average, 45.5% satisfactory and 25% good (Fig 1.). χ2 showed that there was a statistical significant difference between LUHS and VU OF students and their experience while using conventional impressions during university practice (p=0.022).

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Fig 1. LUHS and VU OF students experience rating working with conventional impressions

All respondents, 237 (100%), had no experience working with digital impressions and IOS during university practice.

42% of students in LUHS and 39% in VU stated that they were introduced to IOS and its’ using technique in the university. There was no statistical significant differences between LUHS and VU OF students for an introduction to intraoral scanners (p=0.685).

From 193 total respondents in LUHS, 29.5% were introduced to IOS only theoretically, 2.6% - only practically, 9.8% - theoretically and practically and 58% have not been introduced to IOS in any way. In VU, 27.3% were introduced to IOS only theoretically, 2.3% - only practically, 9.1% - theoretically and practically and 61.4% have not been introduced to IOS in any way.

In LUHS, 6.7% of respondents noted that there is access to IOS which is available for students in the prosthodontics department, 53.9% said that there is no access and 39.4% marked that they have not looked into it. 9.1%, 47.7% and 43.2% were the answers of students at VU respectively. There was

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19 no significant differences between LUHS and VU Odontology faculty students in case of availability of IOS at university (p=0.717).

Obtained data about students’ self-evaluation of knowledge of conventional impressions and procedure technique in LUHS: 1% bad, 2.1% poor, 24.9% average, 39.9% satisfactory and 32.1% good. In VU: 0%, 6.8%, 15.9%, 31.8%, 45.5% respectively (Fig 2.).

Fig 2. Objective self-evaluation of students’ knowledge about conventional impressions and procedure technique

Respondents provided data about knowledge of digital impressions and procedure technique in LUHS: 34.2% bad, 36.3% poor, 20.2% average, 6.7% satisfactory and 2.6% good. In VU: 22.7%, 43.2%, 27.3%, 4.5% and 2.3% respectively (Fig 3.).

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Fig 3. Objective self-evaluation of students’ knowledge about digital impressions and procedure technique

There were no statistical significant difference between both universities of knowledge of conventional (p=0.143) and digital (p=0.551) impressions and their using technique.

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3.2. Conventional versus digital

Table 2. Students’ opinion on digital versus conventional impression techniques

Characteristic University Type Frequency (%) P-value

MORE ACCURATE LUHS Conventional 15.0 χ2=0.0001 Digital 70.0 No significant difference 15.0 VU Conventional 15.9 Digital 40.9 No significant difference 43.2 LESS-TIME CONSUMING LUHS Conventional 28.5 χ2=0.075 Digital 64.2 No significant difference 7.3 VU Conventional 27.3 Digital 54.5 No significant difference 18.2 MORE ACCEPTABLE TO THE PATIENT LUHS Conventional 1.6 χ2=0.334 Digital 94.3 No significant difference 4.1 VU Conventional 4.5 Digital 88.6 No significant difference 6.8 MORE TECHNIQUE SENSITIVE LUHS Conventional 46.6 χ2=0.001 Digital 43.5 No significant difference 9.8 VU Conventional 75.0 Digital 13.6 No significant difference 11.4

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22 The majority (70%) of LUHS participants stated that digital impressions are more accurate than conventional. 40.9% of VU participants said that digital is more accurate and 43.2% that there is no significant difference between digital and conventional impression accuracy. The p-value obtained for comparison of LUHS and VU was 0.0001 which shows us that there is a significant statistical difference between LUHS and VU participants’ answers regarding accuracy.

Digital impressions were selected by the majority of participants in LUHS and VU regarding the time taken for an impression and acceptability to the patient. There was no significant statistical difference between LUHS and VU participant answers.

The majority (75%) of VU participants stated that the conventional impression technique is more technique sensitive and 46.6% of LUHS participants agreed to it. Besides, 43.5% of LUHS participants marked that digital impressions are more technique sensitive. As the p-value of the χ2 was 0.001, it shows us that there is a significant statistical difference between LUHS and VU OF students of what they think which technique is more technique sensitive.

74.6% of the LUHS respondents stated that the time needed to scan both jaws with the intraoral scanner would be from 1 min to 10 min, 16.1% - from 10 min and more and 9.3% - up to 1 min. Alike LUHS respondents, the majority (65.9%) of VU research participants stated that it would take from 1 to 10 min to scan both jaws with an intraoral scanner. 25% - up to 1 min and 9.1% - from 10 min and more. There is a significant statistical difference between LUHS and VU students’ opinions of the time taken to scan both jaws with an IOS (p-value = 0.013).

For the question about the time taken to make an impression of both jaws with a conventional technique, the majority (52.3%) of LUHS respondents said that it would take from 10 min and more, 46.6% from LUHS stated that it would take from 1 min to 10min, and 1% said it would take up to 1 min. The majority of VU students (63.6%) said it would take from 1min to 10 min, 34.1% - from 10 min and more and 2.3% - up to 1 min. The p-value obtained was 0.084, it means that there was no significant statistical difference between LUHS and VU students’ opinion of the time taken to make an impression of both jaws using a conventional impression technique.

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3.3. Advantages, challenges and the future

Table 3. LUHS students’ opinion of the advantages of conventional impression technique

Feature Yes / No Frequency (%)

ACCURACY Yes 35.2 No 64.8 ARCHIVING Yes 4.1 No 95.9 PRICE Yes 83.9 No 16.1 PROCEDURE TIME Yes 14.0 No 86.0 PATIENT CONVENIENCE Yes 4.1 No 95.9

Table 4. VU students’ opinion of the advantages of conventional impression technique

There were no statistical significant differences in the final answers between LUHS and VU participants regarding the advantages of the conventional impression method. Both groups selected price as an advantage (Table 3 and 4).

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Table 5. LUHS students’ opinion of the advantages of digital impression technique

Table 6. VU students’ opinion of the advantages of digital impression technique

Both research groups selected accuracy, archiving and patient convenience as the advantage of the digital impression technique. Additionally, the majority of VU participants (54.5%) selected procedure time as an advantage to a digital method (Table 5 and 6).

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25 The majority (63.7%) of LUHS respondents stated that the biggest challenge for a dentist who is looking to purchase or who already purchased an IOS is the price of the device. Following, 20.2% - mastering of the device, 8.8% - accuracy errors, 4.7% - incomplete scanning capabilities and 2.6% - maintenance. The majority (72.7%) of VU respondents stated that the biggest challenge also was the price. 9.1% - mastering of the device, 9.1% - incomplete scanning capabilities, 6.8% - accuracy errors and 2.3% - maintenance.

The majority of respondents of LUHS and VU, 72% and 65.9% respectively, stated that digital impressions will be the gold standard in the future. 9.3% in LUHS marked that it will not be a standard and 18.7% had no opinion on that topic. In VU, 11.4% and 22.7% respectively. There was no significant statistical difference between the opinions of both universities (p = 0.723).

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3.4. Storage of dental models

100% of the research participants in VU stated that it is necessary to archive patients’ dental models. On the other hand, in LUHS 91.7% of respondents said that it is necessary, 2.1% that it is not a necessity and 6.2% had no opinion on that matter.

Respondents were asked in which way it is easier to archive patients’ dental models. The majority (97.4% of participants in LUHS and 95.5% in VU) stated that it is easier to archive and store the models digitally.

The majority (52.3%) of VU students stated that the most important feature of the digital dental archive is occlusion, following 25% progress of the treatment, 13.6% vertical dimension, 6.8% shape of the teeth and 2.3% colour of the teeth. 43.5% of LUHS respondents picked occlusion, 36.8% progress of the treatment, 10.9% vertical dimension, 7.3% shape of the teeth and 1.6% colour of the teeth. (Fig 4.)

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27 Respondents of both universities were asked if it would be easier for the dentist to design a treatment plan and start restorative treatment when the patient has an archived digital dental model that is made before the treatment or trauma. 92.7% of LUHS respondents stated that it would be easier, 1.6% marked “No” as an answer and 5.7% had no opinion. The majority (97.7%) students of VU said that it would be easier for a dentist and 2.3% had no opinion on that topic.

When asked about the importance of patients with good dental and oral health to have a digital dental model made and stored for the future purposes, majority of LUHS and VU respondents (75.1%, 75.0% respectively) answered it positively, 10.4% of answers in LUHS were negative and 14.5% had no opinion about it. Similar answers were obtained from VU respondents with 15.9% of no importance of having a healthy model stored and 9.1% had no opinion.

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4. DISCUSSION

There are no similar studies based on OF students’ understanding of conventional and digital

impressions and their attitude towards the digital impression storage without the intraoral scanner as the research instrument. With a combination of research results from LUHS and VU, we can say that our research had a volume of whole Lithuanian 4th and 5th odontology students as there are only those two universities in the country.

The clinical dental curriculum in universities around the world includes conventional impressions and their using technique. There was no surprise then 100% of respondents answered that they were using it in university practice. However, there was a significant difference between the experience rating of using conventional impressions between LUHS and VU (p=0.022). VU students rated their experience using conventional impressions in a more positive way than LUHS OF students. (Fig 1.) With 100% of students’ having experience with conventional impressions, compared with 0% digital experience from students and majority who stated that they were not introduced to intraoral scanners theoretically and practically, it can be stated that the objectively evaluated self-knowledge about conventional impressions and its’ procedure technique will be more positively shifted than knowledge about digital impressions. (Fig 2.) (Fig3.)

Digital dentistry is fast-changing market and new digital IOS software and hardware is updated very frequently [22]. Due to that, there is a difficulty in standardization of accuracy values, time spent for scanning, patient acceptance and technique sensitivity. LUHS and VU OF students had the same opinion about the patients’ acceptance and time spent for impression taking. Digital impressions were in favour of these categories. As the studies suggest, digital impressions are superior in case of patient acceptance [14]. LUHS and VU students had no experience with IOS so it was difficult for them to correctly guess which impression method is more advantageous. The time taken for making a digital impression is dependent on the experience of using IOS [17]. Opinions of LUHS and VU students separated when they were asked about the accuracy of two methods. 70% of LUHS students said that digital technique is more accurate than conventional and 40.9% of students from VU agreed to it. The digital impression technique clinically has the same accuracy for single crowns and small bridges. However, keeping, in fact, the broad spectrum of accurate works from conventional impressions it is still counted as the more accurate option [10]. Opinions of students from LUHS and VU about the accuracy of the impression technique were significantly different (p=0.0001) as 43.2% of students from VU stated that there is no significant difference between said techniques. Technique sensitivity

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29 of the impression taking technique is hard to define term. For the respondents, it was explained as which technique is more difficult to perform. The majority of VU students stated that the digital impression technique is more difficult, as LUHS students had split opinions – 46.6% in favour of conventional technique and 43.5% digital.

The vast majority of LUHS and VU students selected the price to be the biggest challenge for a dentist who is looking to purchase IOS. With the changing market, personal discounts and offers from IOS companies it is hard to say the exact price of the hardware and software. One fact is known that for the digital impression system initial investment is bigger [23].

Both universities had no difference in answers about the main advantage of the conventional, as the price was the chosen answer. It may also be the fact that digital impression station requires a bigger initial investment [23]. The majority of LUHS and VU students when asked about digital impression advantages picked archiving and patient convenience. This shows that without the practical use of the IOS, students of LUHS and VU can pick the advantages of the digital technique without prior experience.

The majority of LUHS and VU students stated that it is a necessity to store patients’ dental models for the future and the easier way to archive patients’ dental models would be digital. With conventional models it can be a problem, as it takes physical space, it can chip off and get lost [4]. Avoiding these disadvantages with digital models we can prolong dental cast storage time and increase the usage spectrum of it. Both groups of the research have selected occlusion and progress of the treatment, as the most important feature in the digital dental archive. Digital dental models are being used in orthodontics, for following up on the progress of the treatment [4]. As the majority of the LUHS and VU students’ stated, the digital dental model archive can have a use in prosthodontics too. As students said it would be easier for a dentist to design a treatment plan and start restorative treatment when the patient has an already archived dental model which is made before the treatment or trauma. Three quarters from both research groups (LUHS and VU) said that it is important for a patient with good dental health to make a digital dental model and archive it for the future. The advantages of it would be that the dentist will have patients’ natural sizes and shapes of the teeth, occlusion, vertical dimension and colour of the teeth. Also, digital dental model archive will last for a long time without changing its dimensions.

With the lack of knowledge and experience about digital impressions, the majority of LUHS and VU students think that digital impressions will be a gold standard in the future.

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CONFLICT OF INTERESTS

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CONCLUSIONS

1. There was no statistically significant difference between LUHS and VU OF students’ in case of understanding and self-evaluation of knowledge of conventional and digital impressions procedure technique.

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PRACTICAL RECOMMENDATIONS

I recommend that for the future studies of this kind of research, dentistry students of all academic years would be included; adjustment of the questionnaire could be done in respect of including theory questions to test students’ knowledge which would make it less objective; involve practical use of intraoral scanners for the students’ to evaluate its’ properties more accurately; include more information and questions in the questionnaire about digital storage and the use of it.

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ACKNOWLEDGEMENT

I would like to thank my supervisor Dr. Gediminas Skirbutis for his assistance and collaboration. Additionally, I would like to thank LUHS and VU OF students for participation in my research and their contribution to this study.

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6. Richert R, Goujat A, Venet L, Viguie G, Viennot S, Robinson P, Farges J, Fages M, Ducret M. Intraoral scanner technologies: a review to make a successful impression. J Healthhc Eng. 2017; 2017:8427595.

7. Neville P, van der Zande MM. Dentistry, e-health and digitalization: a critical narrative review of the dental literature on digital technologies with insights from health and technology studies. Community Dent Health. 2020; 37(1):51-58.

8. Muhlemann S, Sandrini G, Ioannidis A, Jung RE, Hammerle CHF. The use of digital technologies in dental practices in Switzerland: a cross-sectional survey. 2019; 129(9):700-707.

9. van der Zande MM, Gorter RC, Wismeijer D. Dental practicioners and a digital future: an initial exploration of barriers and incentives to adopting digital technologies. 2013; 215(11):E21.

10. Ahlholm P, Sipila K, Vallittu P, Jakonen M, Kotiranta U. Digital versus Conventional impressions in fixed prosthodontics: a review. J Prosthodont. 2018;27(1):35-41.

11. Basaki K, Alkumru H, De Souza G, Finer Y. Accuracy of digital vs conventional implant impression approach: a three-dimensional comparative in vitro analysis. Int J Oral Maxillofac Implants. 2017;32(4):792-799.

12. Wei D, Di P, Tian J, Zhao Y, Lin Y. Evaluation of intraoral digital impressions for obtaining gingival contour in the esthetic zone: accuracy outcomes. Clin Oral Investig. 2019. Original article.

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35 13. Arcuri L, Lorenzi C, Vanni A, Bianchi N, Dolci A, Arcuri C. Comparison of the accuracy of intraoral scanning and conventional impression techniques on implants: a review. J Biol Regul Homeost Agents. 2020;34(1):89-97.

14. Mangano F, Gandolfi A, Luongo G, Logozzo S. Intraoral scanners in dentistry: a review of the current literature. BMC Oral Health. 2017; 17: 149.

15. Mangano A, Beretta M, Luongo G, Mangano C, Mangano F. Conventional vs digital impressions: Acceptability, treatment comfort and stress among young orthodontic patients. Open Dent J. 2018;12:118-124.

16. Patzelt SB, Lamprinos C, Stampf S, Att W. The time efficiency of intraoral scanners: an in vitro comparative study. J Am Dent Assoc. 2014; 145(6):542-551.

17. Resende CCD, Barbosa TAQ, Moura GF, Tavares LDN, Rizzante FAP, George FM, Neves FDD, Mendonca G. Influence of operator experience, scanner type and scan size on 3D scans. J Prosthet Dent. 2020;3913(20):30016-0.

18. Zitzmann N, Kovaltschuk I, Lenherr P, Dedem P, Joda T. Dental Students’ perception of digital and conventional impression techniques: a randomized controlled trial. Journal of Dental Education. 2017;81(10):1227-1232.

19. Ahmen KE, Wang T, Li KY, Luk WK, Burrow MF. Performance and perception of dental students using three intraoral CAD/CAM scanners for full-arch scanning. J Prosthodont Res. 2019;63(2):167-172.

20. Wegner K, Michel K, Seelbach PH, Wostmann B. A questionnaire on the use of digital denture impressions in preclinical setting. Int J Comput Dent. 2017;20(2):177-192.

21. Anokhina AV, Abzalova SL. The survey of orthodontists on modern diagnosis and treatment planning of malocclusions in adults. Stomatologija 2020;99(1):61-65.

22. Mangano F, A Shibli J, Fortin T. Digital dentistry: New Materials and Techniques. Int J Dentistry. 2016:5261247.

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ANNEXES

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Annex 2: Questionnaire in Lithuanian language

ANKETA

Aš, Aurimas Čiočys, Lietuvos sveikatos mokslų universiteto odontologijos fakulteto studentas atlieku tyrimą, skirtą nustatyti “LSMU ir VU odontologijos fakultetų studentų supratimą apie įprastinius ir skaitmeninius atspaudus bei įvertinti požiūrį į skaitmeninių duomenų kaupimą”. Tyrimo duomenys bus panaudoti tik studijų tikslams. Anonimiškumas ir gautų duomenų konfidencialumas yra garantuojamas. Apklausa užtruks iki 5 minučių. Kilus neaiškumams galite susisiekti su manimi: Aurimas Čiočys, aurimas.ciocys@gmail.com, 864748088.

Ačiū, kad prisidedate prie mano tyrimo!

1. Kurio universiteto studentė (-as) jūs esate?

a) Lietuvos sveikatos mokslų universiteto b) Vilniaus universiteto 2. Kelinto kurso studentė (-as) jūs esate?

a) Ketvirto (4) b) Penkto (5)

3. Ar universitetinėje praktikoje naudojote įprastinius atspaudus? Jei taip, įvertinkite patirtį.

a) Taip b) Ne

4. Ar universitetinėje praktikoje naudojote skaitmeninius atspaudus? Jei taip, įvertinkite patirtį.

a) Taip b) Ne

5. Ar jūsų universitete buvo supažindinama su intraoraliniais skeneriais ir jų naudojimosi metodika?

a) Taip b) Ne

5.1 Jei atsakėte taip, pažymėkite kokiu būdu jūs buvote supažindinta (-as). Galite pasirinkti abu variantus.

a) Teoriškai b) Praktiškai

6. Ar jūsų universiteto odontologijos fakulteto studentai turi prieigą prie intraoralinio skenerio?

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7. Objektyviai įvertinkite savo žinias apie įprastinius atspaudus ir procedūros atlikimo metodiką.

8. Objektyviai įvertinkite savo žinias apie skaitmeninius atspaudus ir procedūros atlikimo metodiką.

9. Jūsų manymu, kuri atspaudų nuėmimo metodika yra tikslesnė?

a) Įprastinė b) Skaitmeninė c) Nėra reikšmingo

skirtumo

10. Jūsų manymu, kuri atspaudų nuėmimo metodika yra greitesnė?

skirtumo

11. Jūsų manymu, kuri atspaudų nuėmimo metodika yra priimtinesnė pacientui?

skirtumo

12. Jūsų manymu, kuri atspaudų nuėmimo metodika yra labiau techniškai reikli?

a) Įprastinė b) Skaitmeninė c) Nėra

reikšmingo skirtumo

13. Jūsų manymu, kiek laiko trunka abiejų žandikaulių skenavimas intraoraliniu skeneriu?

a) iki 1 min b) nuo 1 min iki 10 min c) nuo 10 min ir

daugiau

14. Jūsų manymu, kiek laiko trunka abiejų žandikaulių atspaudų nuėmimas įprastine metodika?

a) iki 1 min b) nuo 1 min iki 10 min c) nuo 10 min ir

daugiau

15. Kaip manote koks yra didžiausias iššūkis odontologui norinčiam įsigyti ar įsigijus intraoralinį skenerį? Pasirinkite vieną.

a) Priežiūra b) Kaina c) Prietaiso įvaldymas d) Paklaida e) Nepilnos skenavimo galimybės

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16. Ar manote, kad ateityje skaitmeniniai atspaudai taps auksiniu standartu?

a) Taip b) Ne c) Neturiu nuomonės

17. Kaip manote koks yra didžiausias įprastinių atspaudų metodikos pranašumas? Galimi keli atsakymai.

a) Tikslumas b) Archyvavimas c) Kaina d) Procedūros laikas e) Patogumas pacientui 18. Kaip manote koks yra didžiausias skaitmeninių atspaudų metodikos pranašumas? Galimi keli atsakymai.

a) Tikslumas b) Archyvavimas c) Kaina d) Procedūros laikas e) Patogumas pacientui 19. Jūsų manymu, kokiu būdu lengviau yra archyvuoti paciento dantų modelius?

a) Įprastiniu b) Skaitmeniniu

20. Jūsų manymu ar būtina archyvuoti skaitmeninius paciento dantų modelius ateičiai?

21. Jūsų manymu, kuri savybė skaitmeniniame dantų modelių archyve yra svarbiausia? Pasirinkite vieną.

a) Sąkandis b) Vertikalus aukštis c) Dantų forma d) Dantų spalva e) Gydymo eiga 22. Jūsų manymu ar odontologui yra lengviau sudaryti gydymo planą bei pradėti restauracinį gydymą, kai pacientas turi archyvuotą skaitmeninį dantų modelį, kuris yra padarytas prieš gydymą ar dantų traumą?

23. Kaip manote ar svarbu, kad pacientai turintis gerą dantų būklę pasidarytų skaitmeninį dantų modelį ir jį archyvuotų ateičiai?

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Annex 3: Questionnaire in English language.

QUESTIONNAIRE

I, Aurimas Čiočys, a student at the Lithuanian University of Health Sciences, Faculty of Dentistry, am conducting a study to determine “LUHS and VU Odontology Faculty student understanding of conventional and digital impressions and evaluate attitudes toward digital impression storage”. The research data will be used for study purposes only. Anonymity and confidentiality of the data received are guaranteed. The survey will take about 5 minutes. If you have any questions, you can contact me: Aurimas Čiočys, aurimas.ciocys@gmail.com, 864748088. Thanks for contributing to my research!

1. Which university student you are?

a) Lithuanian University of Health Sciences b) Vilniaus University 2. Which year student you are?

a) Fourth (4) b) Fifth (5)

3. Did you use conventional impressions in university practice? If yes, rate your experience.

a) Yes b) No

4. Did you use digital impressions in university practice? If yes, rate your experience.

a) Yes b) No

5. Have you been introduced with intraoral scanners and their using technique in your university?

a) Yes b) No

5.1 If yes, choose in what way you have been introduced. You can choose both answers.

a) Theoretically b) Practically

6. Does your university dental faculty students have access to intraoral scanner?

a) Yes b) No c) Have not looked into it

7. Objectively evaluate your knowledge about conventional impressions and procedure technique.

8. Objectively evaluate your knowledge about digital impressions and procedure technique.

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9. In your opinion, which impression taking technique is more accurate?

a) Conventional b) Digital c) No significant difference

10. In your opinion, which impression taking technique is taking less time?

11. In your opinion, which impression taking technique is more acceptable to the patient? a) Conventional b) Digital c) No significant difference

12. In your opinion, which impression taking technique is more technique sensitive?

13. In your opinion, how long does it take to scan BOTH jaws with an intraoral scanner?

a) up to 1 min b) from 1 min to 10 min c) from 10 min and more

14. In your opinion, how long does it take to make an impressions of BOTH jaws with a

conventional technique?

a) up to 1 min b) from 1 min to 10 min c) from 10 min and more

15. What do you think is the biggest challenge for a dentist looking to purchase or who already purchased an intraoral scanner? Select ONE answer.

a) Maintenance b) Price c) Mastering of the device d) Accuracy errors e) Incomplete scanning capabilities

16. Do you think digital impressions will become the gold standard in the future?

a) Yes b) No c) I have no opinion

17. What do you think is the greatest advantage of conventional impression technique? You can choose more than one answer.

a) Accuracy b) Archiving c) Price d) Procedure time e) Patient convenience

18. What do you think is the greatest advantage of digital impression technique? You can choose more than one answer.

a) Accuracy b) Archiving c) Price d) Procedure time e) Patient convenience

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19. In your opinion, in what way it is easier to archive patient‘s dental models?

a) Conventional b) Digital

20. Do you think it is necessary to archive patient‘s dental models for the future? a) Yes b) No c) I have no opinion

21. In your opinion, which feature is the most important in the digital dental archive? Select ONE answer.

a) Occlusion b) Vertical dimension c) Shape of the teeth d) Color of the teeth e) Progress of the treatment

22. Do you think it is easier for the dentist to design a treatment plan and start restorative treatment when the patient has an archived digital dental model that is made before the treatment or trauma?

a) Yes b) No c) I have no opinion

23. Do you think it is important for patients with good dental health to make a digital dental model and archive it for the future?

FUTURE IS NOW: IMPRESSIONS AND DIGITAL STORAGE

Aurimas Čiočys

FUTURE IS NOW: IMPRESSIONS AND DIGITAL

STORAGE

CONCLUSION OF FINAL MASTER‘S THESIS ACADEMIC SUPERVISOR

ON THE DEFENSE OF THE THESIS

FINAL MASTER‘S THESIS IS APPROVED AT THE DEPARTMENT

Final Master‘s Thesis reviewer

Evaluation of Final Master‘s Thesis Defense Board:

TABLE OF CONTENTS

FUTURE IS NOW: IMPRESSIONS AND DIGITAL STORAGE

SUMMARY

ABBREVIATIONS

INTRODUCTION

1. REVIEW OF LITERATURE

2. MATERIALS AND METHODS

3. RESULTS

4. DISCUSSION

CONCLUSIONS

PRACTICAL RECOMMENDATIONS

ACKNOWLEDGEMENT

REFERENCES

ANNEXES