Attitudes of the Students from the School of Dental Medicine in Zagreb towards CAD/CAM.

AIM: Due to fast and continuing advances in digital dental technology it is important to provide appropriate CAD/CAM education of preclinical (PS) and clinical (CS) dental students. Therefore, the aim of this study was to determine the knowledge and attitudes on CAD/CAM technology of PS and CS at the School of Dental Medicine, University of Zagreb since the obtained results can show the level of students' knowledge and possibly a need for additional education.
MATERIALS AND METHODS: This study included 216 undergraduate dental students from the School of Dental Medicine in Zagreb: 77 (35.6%) of preclinical students (PS) and 139 (64.4%) of clinical students (CS). All participants filled out the questionnaire specially designed for this study. The obtained data were statistically analyzed with a significance level of p<0.05.
RESULTS: Most of the students (182, 84.23%) heard about CAD/CAM technology at regular lectures held at the School (p<0.05). Regardless of their level of education, most of the students (204, 94.4%) did not attend any CAD/CAM course which were not held within regular lectures at the School (p<0.05). Most of PS (72, 33.3%) and most of CS (133, 61.6%) participants believe that they are not sufficiently informed about CAD/CAM technology (p<0.05).
CONCLUSION: Although most of the students (PS and CS) heard about CAD/CAM technology, it could be concluded that they are not sufficiently informed and that additional education on CAD/CAM technology is required. Also, CS students do not posses greater knowledge about CAD/CAM technology than PS students.

Introduction

Computer-aided design (CAD) and computer-aided manufacturing (CAM) is an important and irreplaceable technology in contemporary dentistry in Croatia and worldwide.. CAD/CAM technology was developed in 1960s first for aircraft and automotive industries, while the first CAD/CAM dental restoration was produced in 1980s (, ). From the first use of CAD/CAM technology in dentistry until today, each step in CAD/CAM process was technologically improved through development and improvement of three-dimensional scanning devices, accurate and simpler softwares for design, and milling machines for precise manufacturing of dental restorations (). According to Davidowitz et al. (), CAD/CAM technology was basically developed in order to ensure adequate strength of restorations, to create dental restorations with natural appearance, as well as to enable the whole manufacturing process easier and faster with finally more accurate dental restorations.

A wide range of dental materials can be used by CAD/CAM technology: dental alloys (CoCr alloys, Ti alloys), waxes, polymers, composites, and ceramics. Therefore, CAD/CAM technology has application in many fields of dentistry: restorative dentistry, prosthetic dentistry, dental implantology and orthodontics. Also, there are two ways in prosthetic dentistry how to work with the CAD/CAM technology: chairside system (manufacturing of dental restorations in a clinic) and laboratory system (manufacturing of dental restorations in dental laboratory) (-). Finally, CAD/CAM technology for dental restorations has many advantages over traditional techniques: speed, ease of use, high quality of restorations, saving time for clinician and labor as well as reducing costs (). An important disadvantage of CAD/CAM technology is its initial cost of the equipment and needed software, together with time and money needed for additional education.

Due to CAD/CAM importance in contemporary dentistry, it is important to provide appropriate education about CAD/CAM technology for preclinical and clinical dental students. Although the CAD/CAM technology was primarily developed for clinical application, the use of this technology with the aim of dental students’ education is a new concept embraced by only a few manufacturers (). In that view, in preclinical program CAD/CAM technology enables students to see the difference between their tooth preparations and optimal tooth preparations, as well as to quantify these differences. Students can also design dental restorations and send them to milling machines (). Apart from practical work, theoretical education enables them to know all other details needed for the CAD/CAM usage. If students perceive how digital and electronic technologies are valuable for their future clinical work, there will be a greater chance of their more general acceptance in every day practice (). Therefore, the aim of this study was to determine the knowledge and attitudes of preclinical and clinical dental students from the School of Dental Medicine, University of Zagreb towards CAD/CAM technology since the obtained results can serve as a guide in assessing the current curriculum as well as planning of additional education about CAD/CAM technology.

Materials and methods

This study included 216 undergraduate dental students from the School of Dental Medicine, University of Zagreb. The participants were divided into two groups according to the level of their education: first group consisted of 77 preclinical students (PS) – third year undergraduate dental students, and the second group consisted of 139 clinical students (CS) – fifth year undergraduate dental students. A total number of male participants was 32, while a total number of female participants was 184. The participants were informed about the aims of this study, and their consent for participation in study was obtained. This study was approved by the Ethics Committee of the School of Dental Medicine, University of Zagreb, Croatia.

All participants filled out the questionnaire specially designed for this study. The questionnaire consisted of two sections. In the first section, there were questions about general data of participants (age, gender, and level of education – preclinical or clinical students). The second section of questionnaire consisted of 14 questions designed to evaluate the students’ attitudes towards the CAD/CAM technology in prosthetic dentistry: 1. Have you heard about CAD/CAM? 2. Where did you hear about CAD/CAM? 3. Did you ever see any CAD/CAM restoration? 4. Did you work with CAD/CAM? 5. Did you attend any CAD/CAM course (out of regular lectures at the School? 6. Is it necessary to teach more about CAD/CAM within the regular lectures at the School? 7. Why is CAD/CAM technology useful? 8. Are you sufficiently informed about CAD/CAM technology? 9. Is digital intraoral impression obligatory in CAD/CAM fabrication of dental restoration? 10. Which materials are used in milling machines? 11. The time needed for milling a single crown? 12. Could zirconium oxide blocks have a shrinkage factor? 13. What type of CAD/CAM technology would I use? 14. I would use CAD/CAM technology for?.

The results obtained were statistically analyzed using computer software SPSS 15.0 (SPSS Inc., Chicago, Illinois, United States) by the method of descriptive statistics, χ2 test and Fisher’s exact test with a significance level of p<0.05.

Results

Total number of 216 participants was divided into two groups: 77 (35.6%) PS, and 139 (64.4%) CS. Age range of PS was from 20 to 24 years (mean age was 22 years) and the age range of CS was from 21 to 29 years of age (mean age was 23 years). According to gender, this study included 32 (14.8%) male participants, and 184 (85.2%) female participants. Among PS group, 12 (15.6%) were males while 65 (84.4%) were females. Among CS group, 20 (14.4%) were males and 119 (85.6%) were females.

The results from questionnaire are present in table 1 and table 2. A great number of participants’ answers from questionnaire were statistically significant (p<0.05). All participants (PS and CS) had heard about CAD/CAM technology. Most of them (182, 84.23%) - 60 (27.73%) PS and 122 (56.5%) CS heard about CAD/CAM technology at regular lectures at the School (p<0.05). Regardless of their level of education, most of participants (204, 94.4%) did not attend any CAD/CAM which were not organized within regular lectures at the School (p<0.05). Also, most of PS (72, 33.3%) and most of CS (133, 61.6%) participants believe that they are not sufficiently informed about CAD/CAM technology (p<0.05). Forty eight (22.3%) PS answered that they didn’t see any CAD/CAM restoration (p<0.05). Among CS group of participants, 69 (31.9%) participants saw CAD/CAM restoration and 70 (32.4%) participants did not see any CAD/CAM restoration (p<0.05). Thirty nine (18.1%) of PS and 81 (37.5%) of CS had opportunity to use intraoral scanner (p<0.05). Only 2 (1%) students (regardless of their level of education) thought that CAD/CAM technology is not useful, but the answer is not statistically significant (p>0.05). Only 15 (6.9%) PS and 42 (19.4%) CS knew that digital intraoral impression is not obligatory phase in CAD/CAM fabrication of dental restoration (p<0.05). Only 74 (34.3%) participants - 29 (13.4%) PS and 45 (20.9%) CS knew that all suggested materials could be processed in milling machines (p<0.05). Only 44 (20.7%) participants – 10 (4.6%) PS and 34 (15.7%) CS thought that zirconium oxide blocks could have a shrinkage factor (p<0.05). The minority of participants (63, 29.2%) stated that they would not use CAD/CAM technology in their future work (33, 15.3% of PS and 30, 13.9% of CS) (p<0.05). Most (186, 86.1%) of students (61, 28.3% of PS and 125, 57.8% of CS) would use CAD/CAM technology for fabrication of crowns, bridges, inlays, onlays and combination of all other prosthetic modalities (p<0.05).

Table 1

Distribution of answers from the questionnaire about students’ attitudes about CAD/CAM (questions from 1 to 8).

Preclinical dental students					Clinical dental students
Have you heard about CAD/CAM?										ALL	p value
YES	NO				YES	NO				216100%	1.000
7735,6%	00%				13964,4%	00%
Where did you hear about CAD/CAM?
a	b	c	d		a	b	c	d		216100%	0.000
6027,73%	125,6%	52,3%	00%		12256,5%	136,02%	41,85%	00%
Did you see any CAD/CAM restoration?
YES	NO				YES	NO				216%100%	0.000
2913,4%	4822,3%				6931,9%	7032,4%
Did you work with CAD/CAM?
e	f	NO			e	f	NO			216100%	0.000
00%	3918,1%	3817,6%			31,3%	8137,5%	5525,5%
Did you attend any CAD/CAM course (out of regular lectures at the Faculty)?
YES	NO				YES	NO				216100%	0,000
21%	7534,7%				104,6%	12959,7%
Is it necessary to teach more about CAD/CAM within the regular lectures at the Faculty?
g	h	YES			g	h	YES			216100%	0.929
41.9%	00%	7333.8%			104.6%	20.9%	12758.8%
Why is CAD/CAM technology useful?
i	j	k			i	j	k			216100%	0.874
2411%	5224.1%	10.5%			3616.7%	10247.2%	10.5%
Are you sufficiently informed about CAD/CAM technology?
YES	NO				YES	NO				216100%	0.000
52.3%	7233.3%				62.8%	13361.6%

a-regular lectures at School; b - at School but out of regular lectures; c-out of School; d-I did not hear; e-yes, I fabricated dental restoration; f-I used only intraoral scanner; g-no, CAD/CAM is enough involved in teaching; h-no, CAD/CAM should not be involved in teaching; i-better aesthetics and longevity of dental restoration; j-shorter fabrication time; k-CAD/CAM technology is not useful.

Table 2

Distribution of answers from the questionnaire about the students’ attitudes about CAD/CAM (questions from 9 to 14).

Preclinical dental students					Clinical dental students					ALL	p value
Is digital intraoral impression obligatory in CAD/CAM fabrication of dental restoration?
YES	NO	l			YES	NO	l
3415.7%	156.9%	2813%			8840.7%	4219.4%	94.3%			216100%	0.000
Which materials are used in milling machines?
m	n	o	p	q	m	n	o	p	q
00%	10.5%	2310.6%	2913.4%	2411.1%	10.5%	20.9%	8137.5%	4520.9%	104.6%	216100%	0.000
The time needed for milling a single crown?
≤1hour	>1hour	r			≤1hour	>1hour	r			216100%	0.137
3415.7%	125.6%	3114.4%			8740.3%	146.4%	3817.6%
Could zirconium oxide blocks have a shrinkage factor?
YES	NO	s			YES	NO	s			216100%	0.000
104.6%	146.5%	5324.5%			3415.7%	3114.4%	7434.3%
What type of CAD/CAM technology would I use?
t	u	v			t	u	v			216100%	0.000
2411%	209.3%	3315.3%			4420.4%	6530.1%	3013.9%
I would use CAD/CAM technology for?
w	x	y	z	aa	w	x	y	z	aa	216100%	0.007
104.6%	62.8%	3616.7%	00%	2511.6%	83.7%	41.9%	8539.4%	20.9%	4018.4%

l-I don’t know; m-wax; n-alloy; o-zirconium oxide; p-all listed materials; q-I don’t know; r- I don’t know; s- I don’t know; t-InLab system; u-InOffice system; v-I don’t plan to use CAD/CAM technology; w- I don’t plan to use CAD/CAM technology; x-provisional restorations; y-inlay, onlay, veneers, crowns and bridges; z-telescopic crowns and abutments; aa-combination of all prosthetic modalities.

Discussion

Digital dental technology is unavoidable in everyday clinical practice. At present, dental students are growing up in a digital world, which consequently reflects their preferences, expectations and the way of acquiring new knowledge. Students increasingly show the affinity for including digital technology into teaching and education (). Also, a rapid development of digital technology is a challenge for teachers and it requires constant adjustments and changes in the curriculum. Since the use of CAD/CAM technology is rapidly expanding, many Schools of Dental Medicine around the world have integrated it into their preclinical and clinical curriculum (-). Therefore, this study was performed with the aim to determine knowledge and attitudes about CAD/CAM technology of PS and CS at the School of Dental Medicine, University of Zagreb. The results obtained in this study can indicate if additional education of PS and CS about CAD/CAM technology is required due to the increasing popularity of CAD/CAM technology in dental clinics and laboratories in Croatia. According to the data from literature (), in 2010, there were more than 27,000 CEREC systems placed in dental medicine in over 50 countries, while about 4500 in Lab units were used in dental laboratories. Although there is a wealth of literature (-, -) about CAD/CAM technology, little is known about knowledge and awareness of CAD/CAM technology among students and dentists in the world; hence this is also the first study of this kind which was conducted in Croatia.

The study included two groups of students from the School of Dental Medicine at University of Zagreb: PS and CS group of students. PS students were the third year of undergraduate dental students while CS students were in their fifth year of undergraduate dental studies. In each group, the number of female participants was higher than the number of male participants. This difference in number of participants with regard to the gender could be explained by high and steadily rising percentage of women in European dentistry, which can also be described as the feminization of dental profession (). All the students enrolled in the School of Dental Medicine in Zagreb heard about CAD/CAM technology. Similar results were found by Popa et al. () where majority of students also heard about CAD/CAM technology as well as saw CAD/CAM system. But majority of students from study by Popa et al. () did not see any CAD/CAM restoration, which is similar to answers of PS group of participants of this study. Most of the students from the School of Dental Medicine in Zagreb heard about CAD/CAM technology at their regular lectures held at the School, and usually they did not attend any additional courses that were held out of the School. For comparison, Tran et al. () reported that dentists from the United Kingdom had undertaken only training of CAD/CAM technology by companies providing CAD/CAM systems, private courses or were taught by other CAD/CAM users, while participants did not mention CAD/CAM education at the School. Due to the fact that dental students have a higher preference for visual learning than general student population (), Illinois and Indiana University Schools of Dental Medicine incorporated CAD/CAM in their curriculum, in order to enable students to virtually design crowns using CAD techniques (, ). The authors (, , ) reported that incorporating of CAD/CAM technology in preclinical and clinical curriculum positively affects students’ attitudes regarding CAD/CAM technology. In this study, most of PS and CS students consider CAD/CAM technology useful, and many of them highlighted the shorter fabrication time as the main reason. In the study by Popa et al. () most of students stated with great enthusiasm that CAD/CAM technology represents the future of prosthetic dentistry.

Almost all of the students in the present study heard about CAD/CAM technology and have positive attitudes about it, but they also stated that were not sufficiently informed and that additional education within the regular lectures at the School is required. In most of the cases, distribution of answers from the questionnaire was similar among the PS and CS group of participants. Therefore, the minority of PS and CS participants knew that intraoral digital impression is not obligatory in CAD/CAM technology because a stone model can be scanned in laboratory (), fewer PS and CS participants stated that all suggested materials (wax, alloys, zirconium oxide) can be processed in CAD/CAM machines, and that zirconium oxide blocks can have a shrinkage factor. In a study by Popa et al. () only 19.1% of students, and in study by Kavarthapu et al. () 36.2% of students stated that all suggested materials could be processed in CAD/CAM machines. In the same study (), only 11.4% of students knew that zirconium oxide CAD/CAM blocks have shrinkage factor. According to results from present study it could be concluded that additional education of students about CAD/CAM technology is required but it cannot be concluded that CS students have greater theoretical knowledge about CAD/CAM technology than PS students. The most important fact is that students, regardless of their level of education, have positive attitudes regarding the CAD/CAM technology and that just a small number of them is not planning to use CAD/CAM technology in the future.

Conclusion

All students (PS and CS) heard about CAD/CAM technology, mostly during their regular lectures at the School. The students have positive attitudes regarding CAD/CAM, and only the minority of them will not want to use CAD/CAM technology in the future. But according to the results it could be concluded that they are not sufficiently informed about CAD/CAM and that additional education about CAD/CAM technology would be a good option. It cannot be concluded that CS students have greater knowledge about CAD/CAM technology than PS students.