Conventional vs. Digital Impression: Comfort Level, Preferences, and Acceptance of Treatment Time among Orthodontic Patients

1. INTRODUCTION

The escalated technological development and the emergence of computer-aided manufacturing have improved dental restoration accuracy and the accurate manufacturing of prosthetic models [1]. Its growth has continued to propel since the 1980s when novel study models, such as intraoral scanners, have drastically increased among orthodontists. There is a considerable increase in intraoral scanners to obtain study models among orthodontists [2]. This technological break-through in dentistry has increased the digital impression efficiency, information storage capacity, and digital image transfer from the dental office to the laboratory [3].

Despite the increasing accuracy of digital impression technology, its full integration has not yet been achieved, given the conventional impression endurance [4, 5]. The conventional impression techniques encompass hydrocolloid and elastomeric materials, such as polyvinyl siloxane and polyether. The main factors that lead to the sustainment of the conventional impression technique are its accuracy, acceptance, and inexpensiveness [6]. Reflecting upon both techniques' execution time, the impression time using contemporary technology is shorter than the conventional impression approach [6]. Mangano et al. [7] stated that digital impression reduces the patients' discomfort and saves storage and time as no pouring of the stone cast is required.

Further advantages of the digital scanning systems are the option to easily transfer digital data to the dental technician via email, avoiding impression shipping to the laboratory, which results in better communication with the laboratory [8]. Impression in adolescents is obtained for diagnosis and treatment processes in orthodontics and pediatric dentistry through habit breaker fabrication, space maintainer, etc [9]. In impression taking, a digital revolution is now apparent in dentistry. As systems in this sector advance, a total transformation of the impression-taking method, regarded as the worst experience by patients and children, may be predicted [10].

Various studies have been conducted on the accuracy of the digital models for the scanner, while very few have addressed the patients' perception of it [11]. Moreover, these studies have reported divergent results regarding the patients' preference for conventional or digital impression techniques [10, 12, 13]. Furthermore, those studies did not consider other important factors, such as patient comfort, performance, efficiency, and cost, which disrupted the preference for digital and conventional impression techniques [1, 13]. The impression material used in previous studies was used for prosthetic and implant restorations, not for orthodontic treatment.

Digital impressions provide efficiency, attain captured information indefinitely, speed, and transfer digital images between the laboratory and dental office techniques [1, 13]. Also, most patients prefer digital impressions due to their efficiency in providing a comfortable experience [14]. Several studies on the accuracy of digital impressions and intraoral scanners have been published, which give discussions on full arch scans, several teeth in a row, quadrants, and single-unit restorations [15-17]. In their research, Burzynski et al. [18] compared and contrasted patient satisfaction and time required with two intraoral scanners and traditional alginate impressions. The findings revealed that respondents who received intraoral scans preferred digital impressions, whereas those who received alginate impressions were neutral, and that efficiency differed depending on the impression method. Yilmaz et al. [19] conducted a study to determine the impact of impression technique (conventional preliminary alginate and digital scan) and operator experience (experienced in digital and conventional, experienced in conventional and inexperienced in digital, and inexperienced in conventional and digital) on impression time, satisfaction, stress levels, and operator preference. The findings demonstrated a significant interaction between the operator's impression-making experience and the impression technique on time for maxillary and mandibular arch impressions and overall time (p 0.002). The combination between operator experience and impression method significantly impacted comfort and average VAS values (p 0.016). On the other hand, this interaction did not substantially affect stress (p 0.195).

A network meta-analysis was used to find statistical evidence on overall patient preferences for digital vs. traditional impression processes and the time it took to make these impressions. The time taken for 589 patients was reported in 11 trials (278-digital; 311 conventional). The 95 percent confidence range for the pooled estimate (2.72 [0.08, 5.32]) revealed a statistically significant increase in the time required to generate digital imprints. The overall time taken in minutes for the interventions in the digital group in decreasing order was as follows: LAVA Cos (8.14[3.64,12,26] (statistically significant); I tero (4.11[-1.02,9.24]; CEREC (0.34[-4.14,4.82]) [20]. A systematic review of the validity and reliability of intraoral scanners was conducted by Aragón et al. [21] in their study; they included four articles for qualitative synthesis and found that among them, only one of the studies evaluated the time required to complete the clinical procedures as well as taking patients' opinion about the treatment procedures. Thus, the study intended to assess patients' comfort level, preferences, and acceptance of treatment time for conventional impression technique vs. digital impressions among orthodontic patients. They have been receiving clear aligner treatment. Only a few studies have compared patient preference and comfort with both impression techniques, particularly among adult patients [22-25].

2. MATERIALS AND METHODS

3. RESULTS

Before the questionnaire dissemination, its items were assessed for reliability through Cronbach Alpha coefficients. The value achieved for the 31 items was 0.967, indicating its increased reliability (Table 1).

The baseline characteristics of the participants are demonstrated in Table 2. Based on the table, it was found that the majority of the participants, 48(96%), were Saudi, whereas only 2(4%) participants were non-Saudi. The residing city for most of the participants was Riyadh 47(94%), while the remaining 3(6%) participants belonged to other cities in the country. Responses also indicate that most of the patients, 17(34%), were aged between 23- 27 years and 28-32 years 12(24%).

Concerning the gender of the participants, females constituted 29 (58%) of the sample while males were 21(42%). Most of the patients were married, 33 (66%), while only 1 (2%) was a widow. Most of the participants, 37(74%), were university students, and 35 (70%) of the participants were employed.

Table 3 presents the patients' responses regarding the treatment level based on their impression method. 17(34%) of the group 2 participants indicated that the treatment method bothered patients, whereas 12(24%) of group 1 participants agreed with the following statement (P-value: 0.426). Both groups firmly decided on the shortness of breath, respectively, with 21(42%) participants in each (P-value: 0.442) (Table 3). The feeling of being anxious was reported by 19(38%) of the group 2 participants and 21(42%) participants from group 1 (P-value: 0.274). Both groups agreed that they experienced a feeling of helplessness during their treatment, with the values of 15(26%) in patients in group 2 and 19(38%) in patients from group 1 (P-value: 0.983).

Table 3 also presents the patients' perceptions of their impression of the lower jaw. It exhibits that gag reflex was experienced majorly by group 1 participants, 20(40%), and only 17(34%) participants from group 2 had a similar experience; however, no difference in gag reflex experience was found among the two groups, which was found to be statistically non-significant (P-value: 0.088). The effect of the impression technique on breathing was neutrally reported by participants in both groups, while the comfort level was neutral for both groups. Unbiased answers were written for queasiness, where most of group 2 reported its occurrence.

Perception of the impression of the upper jaw is also depicted in Table 3. Based on the results, it was found that gag reflex was almost neutral for the participants in both the groups, 17(34%) in group 1 and 15(30%) in group 2 (P-value: 0.729). 25(50%) participants from group 2 and 18(36%) participants from group 1 did not feel queasiness (P-value: 0.106). During the upper jaw impression, participants of both groups experienced difficulty in breathing. Only 16(32%) from group 2 and 20(40%) from group 1 reported ease in breathing (P-value: 0.319). The comfort level during the treatment was found to be higher in digital impression patients 23(46%) than patients in group 119(38%) (P-value: 0.436).

4. DISCUSSION

The baseline characteristics concerning orthodontic care have depicted that most of the patients were in their early teenage [23]. A study has shown that 41% of dental clinicians use digital models as diagnostic records [26]. Simultaneously, their research emphasized the significance of “CAD/CAM – computer-aided design/computer-aided manufacturing” technology, as it gives enhanced results and abridged functioning time, from impression to framework. It serves as an opportunity for dentists to design, milling, and do ceramics restoration in a single sitting, which ultimately improves patient acceptance, attains patient satisfaction through positive feedback, and eventually augments clinical outcome and reliability. This technology has enumerated a persistent increase in practice in many fields of dentistry, such as pediatric dentistry, prosthodontics, conservative dentistry, orthodontics, etc. The ultimate bond strength to CAD/CAM material for both resin cements is eventually dependent on the method used for surface treatment, constituents of CAD/CAM or resin cements, structure of different CAD/CAM blocks and impact of surface treatment on other materials due to material based special effects [24].

However, six years have been recorded for the downward trend in casts made from conventional impressions [26]. Contemporary orthodontics are interested in knowing the patients' perceptions of conventional and digital impression procedures. The technicalities of the conventional impression are not likely to be applied to the intraoral scanners, which makes these scanners superior and more user-friendly. Results of the present study have shown that digital impression techniques are preferred by the participants in terms of their time, taste/smell, and sensitivity. These findings were consistent with the previous studies where participants preferred the digital scan and reported minor inconvenience [1, 16, 27-29].

The carryover effects occurred when the impressions were taken at the first visit. For this purpose, a washout period is needed between the appointments for at least four weeks. A similar study conducted by Burhardt et al. [23] showed an insignificant difference between the conventional and digital impressions; however, the digital methods were more favored. A study conducted by Syrek et al. [15] stated that most patients preferred alginate impression methods because it was faster and much easier. Similarly, an intraoral scanner was selected by 27% of the respondents because it was more comfortable. This aspect can be explained by the time required for average chairside time for the alginate impressions [23]. However, the present study has used polyvinyl siloxane impression (polyvinyl siloxane, 3M ESPE, Dental Products, St. Paul, MN, USA) as a conventional impression and not with alginate. The participants preferred the conventional impression procedure rather than the digital one, which was based on the patients' perceptions.

The conventional impression procedure is preferred over the digital one, for instance, Lava C.O.S. “Lava C.O.S., 3M ESPE, St. Paul, MN, USA”, being a digital impression procedure, which would require three separate scans to determine the interocclusal relationship. On the contrary, the conventional procedure would only require a single scan [23]. The heterogeneity of the involved factors makes it difficult to compare the registered chairside times with similar studies. These factors include variation in digital processing methods of acquired impression, operator’s experience, and different impression methods [17, 29]. In most cases, 3-dimensional models are acquired, such as the placement of cheek extractors or patient tutorials. The Likert scores were distributed in both directions in each impression technique, regardless of the real chairside time in minutes.

The increased level of expectation among the patients is associated with a decreased tolerance level for the time required for the conventional method rather than a new impression method. The present study has a limitation as it has not reported any relationship between larger mouth opening and better accessibility of the handpieces within the oral cavity. However, the present study has compared the conventional and digital impression methods requiring scanning power to obtain the shortest intraoral scanning time. Previous studies have contradicted the claims made by the manufacturer regarding the superiority of no-powder scanning based on arbitrary assumptions [17, 20-30]. The polyvinyl siloxane scores were high compared to the digital impressions after summing the total perceptions scores for breathing difficulty, gag reflex, uncomfortable feeling, and queasiness. However, the study has failed to directly compare its results with the previous studies due to the differentiation in the perception results by the jaw. CAD/CAM technology allows a completely digital workflow, from impression to final framework for interceptive and multi-brackets orthodontic treatments [31-33].

This study only collected data from 50 adult orthodontic patients using a convenience sampling method. The inclusion of the purposive sampling method can help recruit patients to obtain pre-clinical and didactic instructions related to conventional and digital impressions. The current study has a limitation in that it only tested patient's perceptions and preferences over a short period with a limited sample size; however, future studies are needed to evaluate further mechanical characteristics to analyze and estimate tested materials' behavior thoroughly and can be helpful if future studies extend the period to understand the comfort level, preferences, and acceptance of treatment time on a larger sample. Moreover, patient counseling over the adopted technique by the clinician could also play a significant role in selecting an appropriate technique that could be more beneficial to the patient.

CONCLUSION

The present study has compared the perceptions and patient preferences for conventional impressions vs. digital impressions among the orthodontic patients receiving polyvinyl siloxane and digital impressions. It has been shown that treatment methods bothered patients as they experienced helplessness during their treatment. An insignificant association between comfort level and treatment of the patients was found. At the same time, there was a significant impact on patients' perception of the treatment provided. It has been concluded that the digital impression technique was accepted as the preferred and effective technique, according to the subjects' perception, as compared to the conventional impression technique, and irreversible materials like “polyvinyl siloxane impressions” can be altered through a paradigm shift toward digital intraoral scanners. However, future studies need to conduct well-designed research to depict patients' experiences with digital impressions.

REFERENCES