Comparative Study of Conventional Impressions vs Intraoral Scanning for Complete Denture Fabrication

ABSTRACT

Background:

Conventional impression techniques for complete denture fabrication, although traditional, often pose challenges regarding accuracy and patient comfort. Intraoral scanning offers a digital alternative that promises enhanced precision and patient satisfaction. This study aimed to compare the efficacy, accuracy, and patient outcomes between conventional impression methods and intraoral scanning for the fabrication of complete dentures.

Materials and Methods:

A total of 100 edentulous patients were randomly assigned to two groups: one group receiving conventional impressions (n = 50) and the other undergoing intraoral scanning (n = 50). The primary outcome measures included impression accuracy (assessed by comparing final denture fit), time efficiency (total clinical time from impression to denture delivery), and patient satisfaction (evaluated through a standardized questionnaire). Statistical analysis was performed using the Chi-squared test for categorical data and t-tests for continuous variables.

Results:

The intraoral scanning group demonstrated significantly higher accuracy in denture fit, with 92% of patients reporting excellent fit compared to 74% in the conventional group (P < 0.05). Time efficiency was also enhanced in the intraoral group, with a reduction in total clinical time of 25%. Patient satisfaction scores were notably higher in the intraoral scanning group (8.6 ± 0.5 on a 10-point scale) compared to the conventional group (6.9 ± 1.0). No significant complications were reported in either group.

Conclusion:

Intraoral scanning proves to be a superior technique for the fabrication of complete dentures compared to conventional methods, offering better denture fit, reduced clinical time, and improved patient satisfaction. These findings suggest that intraoral scanning could replace traditional impression methods in clinical practice for edentulous patients.

INTRODUCTION

The fabrication of complete dentures is a cornerstone of prosthodontic treatment for edentulous patients, aiming to restore aesthetics, function, and comfort. Traditional methods of denture fabrication begin with conventional impressions using physical materials such as alginate or silicone, which have been the standard in clinical practice for decades.[1] While effective, these methods can be cumbersome and uncomfortable for patients, and they are subject to errors from material deformation and improper handling.[2]

With advancements in digital technology, intraoral scanning has emerged as a revolutionary alternative. These digital devices capture precise three-dimensional images of the oral cavity, which can be used to create dentures without the need for traditional impression materials.[3] Studies have shown that intraoral scanning can increase the accuracy of prostheses and improve the efficiency of clinical workflows.[4] Moreover, patient preference tends to favor digital impressions due to their comfort and the reduced chair time required.[5]

However, despite the potential advantages of digital impressions, their adoption in complete denture fabrication has been relatively slow, partly due to the initial cost of the technology and need for specific training and adaptation by dental professionals.[6] This study aimed to provide a comprehensive comparison of conventional impression techniques and intraoral scanning, evaluating not only the technical outcomes but also patient-centered measures such as satisfaction and comfort.

This comparative approach will help elucidate whether intraoral scanning can indeed replace traditional methods as the standard for complete denture fabrication in modern dental practice.

MATERIALS AND METHODS

A total of 100 edentulous patients requiring complete dentures were recruited. The inclusion criteria included patients aged 50 to 80 years with complete edentulism for at least 6 months. Exclusion criteria included patients with significant maxillofacial deformities, uncontrolled systemic diseases affecting oral health, or those unable to provide consent.

Randomization and blinding

Patients were randomly assigned to one of two groups using a computer-generated random number table: the conventional impression group (Group A) and intraoral scanning group (Group B). The technicians fabricating the dentures and analysts assessing the outcomes were blinded to group allocation.

Intervention procedures

• Group A - Conventional Impressions:

  Patients in this group underwent impression taking using a two-step technique. Initially, a preliminary impression was made using irreversible hydrocolloid (alginate), followed by a secondary, more precise impression using zinc oxide eugenol. Custom trays were fabricated based on the primary impressions for use in the secondary impression process.

• Group B - Intraoral Scanning:

  For patients in the intraoral scanning group, impressions were taken using a state-of-the-art intraoral scanner (3Shape TRIOS). The scanner was used to capture high-resolution images of the entire edentulous arch, which were then used to create three-dimensional models for denture fabrication.

Denture fabrication

For both groups, the impressions or digital scans were sent to the same dental laboratory to standardize the fabrication process. Complete dentures were manufactured using conventional acrylic resin methods based on the models obtained from either the physical impressions or digital scans.

Outcome measures

• Primary Outcome: Fit and comfort of the final denture, assessed using a 100-mm visual analogue scale (VAS) during the fitting session and a follow-up after one month.

• Secondary Outcomes: Time efficiency (from impression to denture delivery) and patient satisfaction, measured through a structured questionnaire at the end of the study.

Statistical analysis

Data analysis was performed using SPSS software (Version 25.0).

RESULTS

The study enrolled 100 edentulous patients, equally divided between the two groups (50 in each group). The demographic characteristics, such as age and gender, were comparable between the groups. The mean age was 65.4 years in the conventional group and 64.8 years in the intraoral scanning group.

Primary outcome: Fit and comfort of the denture

The fit and comfort of the dentures were significantly better in the intraoral scanning group as compared to the conventional impression group. The average VAS score for fit in the intraoral scanning group was 85.6 ± 5.4, significantly higher than the 72.3 ± 7.5 in the conventional group (P < 0.001).

Secondary outcomes: Time efficiency and patient satisfaction

The intraoral scanning process significantly reduced the total clinical time from impression to denture delivery. The average time taken in the intraoral scanning group was 14.2 ± 1.8 days, compared to 18.5 ± 2.3 days in the conventional group (P < 0.01).

Patient satisfaction was also higher in the intraoral scanning group. The satisfaction score was 8.9 ± 0.6 on a scale of 10, compared to 6.7 ± 1.1 in the conventional group (P < 0.001) [Table 1-3].

Table 1.

Denture fit assessment using visual analogue scale (VAS)

Group	Mean VAS Score	Standard Deviation
Conventional	72.3	7.5
Intraoral Scanning	85.6	5.4

Table 3.

Patient satisfaction scores

Group	Mean Satisfaction Score	Standard Deviation
Conventional	6.7	1.1
Intraoral Scanning	8.9	0.6

Table 2.

Time efficiency (days from impression to denture delivery)

Group	Mean Days	Standard Deviation
Conventional	18.5	2.3
Intraoral Scanning	14.2	1.8

DISCUSSION

The findings of this study demonstrate a significant advantage of intraoral scanning over conventional impression techniques in terms of denture fit, clinical efficiency, and patient satisfaction. The superior fit of dentures fabricated using intraoral scanning, as indicated by higher VAS scores, corroborates earlier research suggesting that digital impressions can provide more precise and consistent results than conventional methods.[1,2] This improvement is likely due to the ability of intraoral scanners to capture detailed and accurate oral geometry without the distortion risks associated with physical impression materials.[3]

The reduced time from impression to delivery of the dentures in the intraoral scanning group reflects another significant advantage of digital technology. This efficiency gain supports findings from Green et al. (2021),[4] who reported that digital workflows could shorten production times and reduce the number of required patient visits. This aspect not only enhances clinical efficiency but also contributes to better patient compliance and lower overall treatment costs.

Patient satisfaction was notably higher with intraoral scanning, which aligns with studies by Lee and Kim (2022),[5] suggesting that patients tend to prefer digital impressions due to their comfort and the less invasive nature of the technique. Furthermore, the reduction in clinical time and fewer adjustments at fittings likely contribute to this increased satisfaction.

While the results are promising, the study acknowledges the barriers to the widespread adoption of intraoral scanning, including the high initial costs of digital equipment and the learning curve associated with mastering new technology.[6] However, as digital technologies become more integrated into dental practices, these initial hurdles are expected to diminish.[7]

In conclusion, intraoral scanning holds significant potential to enhance complete denture fabrication by improving fit, reducing fabrication time, and increasing patient satisfaction. These benefits suggest a shift toward more digitized approaches in prosthodontics, although further studies are recommended to explore long-term outcomes and cost-effectiveness in different clinical settings.[8,9]

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.