Awareness And Knowledge Of Thermoformed And Direct 3D Printed Aligners Among Orthodontic Postgraduate Students: A Questionnaire Based Survey

Clear aligner therapy has revolutionised orthodontic treatment by providing an esthetic, comfortable, and patient-friendly alternative to conventional fixed appliances. Over the past two decades, aligners have gained widespread acceptance due to advancements in digital workflows, improved materials, and enhanced treatment predictability. ¹

Traditionally, clear aligners are fabricated using thermoforming techniques over three-dimensional (3D) printed dental models. This indirect method has been the standard approach in systems such as Align Technology’s Invisalign and other commercially available aligner systems. ² However, recent developments in digital dentistry and additive manufacturing have led to the introduction of direct 3D printed aligners, which eliminate the need for intermediate physical models and streamline the fabrication process. ³

Thermoformed aligners are widely used due to their proven clinical effectiveness, ease of fabrication, and extensive clinical validation. In contrast, direct 3D printed aligners represent an emerging innovation with potential advantages such as improved accuracy, better control over force delivery, reduced material wastage, and shorter production time. ⁴ Despite these benefits, the technology is still in its early stages, and clinical evidence regarding its efficiency and long-term outcomes remains limited.

Orthodontic postgraduate students play a crucial role in the future adoption and dissemination of new technologies in clinical practice. Their awareness, knowledge, and attitude toward evolving aligner systems can significantly influence treatment trends and patient care. However, there is a paucity of literature assessing their understanding of both thermoformed and direct 3D printed aligners.

Therefore, the present study was conducted to evaluate the awareness and knowledge of thermoformed and direct 3D printed aligners among orthodontic postgraduate students.

MATERIALS AND METHODS

Study Design

Cross-sectional questionnaire-based survey.

Study Population

Orthodontic postgraduate students from various dental institutions.

Sample Size

Total participants: 125

Inclusion Criteria

• Orthodontic postgraduate students
• Willing to participate

Exclusion Criteria

• Incomplete responses
• Undergraduate students

Questionnaire Design

A structured questionnaire consisting of:

• Clinical Experience in Aligners
• Awareness About Thermoforming Aligner
• Awareness About Direct 3D Printed Aligners 
• Bio-mechanics of Aligners
• Comparative Knowledge of aligners
• Case selection and Limitation 

Data Collection:

Data were collected via Google Forms.

Statistical Analysis:

Chi-square test analysis revealed no statistically significant association between the year of postgraduate training and aligner usage (χ² = 3.13, p = 0.209). Similarly, no significant association was observed between the year of study and awareness of direct 3D printed aligners (χ² = 2.12, p = 0.346).

However, a statistically significant association was found between the year of postgraduate training and the type of aligner system used (χ² = 21.13, p = 0.0017).

RESULTS:

Fig. 1 shows that the majority of respondents were second-year postgraduate students (45.6%), followed by first-year (36%) and third-year students (18.4%). Fig. 2 shows that Most participants (81.6%) reported using aligners in clinical practice or training, while 18.4% had no experience with aligners.

Fig. 3. Most aligner users preferred Smile Aligners (71.9%), followed by other systems (14.9%), Invisalign (8.8%), and Ormco Spark (4.4%). Fig. 4 Thermoforming was the dominant fabrication method (84%), while only 16% used direct 3D-printed aligners, indicating that conventional vacuum-forming remains the current standard

Fig. 5 shows that A strong majority (87.2%) agreed that aligner therapy should be limited to mild-to-moderate cases, indicating a preference for traditional appliances in complex cases.  Fig. 6 shows that Most practitioners had limited experience, with 77.6% treating only 1–5 cases and 19.2% having no experience, while very few (3.2%) had managed more than 5 cases.

Fig. 7   shows that the Most practitioners (89.6%) were aware of thermoforming techniques, highlighting it as a well-established concept. Additionally, Fig. 8 shows 90.4% correctly identified vacuum/pressure forming over printed models as the primary fabrication method, with only a small minority unsure or incorrect.

Fig.  9 shows that Most practitioners (87.2%) correctly identified thermoforming as the primary fabrication method for commercial aligner systems. Additionally, Fig. 10 shows that 81.6% acknowledged its limitation of causing material thickness variations, with only a small minority disagreein

Fig. 11 shows, the clinical practice, PET-G (Polyethylene terephthalate glycol) is the most widely utilized material for thermoformed aligners, favored by 87.2% (n = 109) of respondents. Polyurethane is used by a significantly smaller segment (8.8%, n = 11), while other materials such as Polypropylene represent only a marginal fraction of the total usage.

Fig.  12 & 13 shows that the survey indicates a very high level of professional awareness, with 94.4% (n = 118) of practitioners familiar with direct 3D printed aligners. The primary driver for this awareness is professional education, as 60% of respondents cited Conferences/CDE programs as their main source of information, followed by Social media (26.4%) and Scientific journals (11.2%).

Fig.  14,15, 16 & 17 shows that the technical awareness of direct printing is high, with 86.4% (n = 108) of practitioners correctly identifying the process as direct 3D printing of aligner material rather than thermoforming. While 78.4% (n = 98) reported general awareness of commercially available direct-printed systems, specific brand recognition was heavily concentrated. Among those aware, over 90% identified Graphy (and its various subsidiaries/registrations) as the primary commercial provider, highlighting its dominant position in the direct-print market.

Fig.  18 & 19 shows ,  In current clinical practice, thermoforming remains the dominant modality (84%) compared to direct 3D printing (16%). While 50.4% of practitioners agree or strongly agree that direct printing eliminates the need for physical models, a large plurality (49.6%) remains neutral on this workflow benefit. Regarding material science, 76.8% (n = 96) of respondents identified flexible biocompatible resin as their material of choice for direct fabrication, significantly outpacing standard photopolymer resins (13.6%).

Fig.  20, 21 & 22 shows   Based on the 125 responses, the vast majority of practitioners (88.8%) are familiar with the push-pull mechanism in aligner therapy. They primarily attribute push forces to the elastic deformation of aligner material (79.2%) and identify optimized attachments as the leading method (76%) for achieving pull mechanics.

In Fig. 23, 24, 25 & 26 , Based on the 125 responses, the survey highlights a clear consensus on difficult movements and the specific attachments used to manage them:

• Difficulties: Extrusion is overwhelmingly cited as the most difficult tooth movement to achieve with aligners (62.4%).
• Attachment Functions:
  • Horizontal Rectangular: Primarily used to facilitate extrusion (68%).
  • Ellipsoid: Mostly utilized for managing torque (65.6%).

Vertical Rectangular: Predominantly used to control rotation (77.7%).

The survey results indicate a strong professional preference for Direct Printed Aligners across most functional categories. Respondents overwhelmingly believe they offer better mechanical properties, superior force control, and improved cost-effectiveness while streamlining the manufacturing process. However, there is a notable trade-off, as a significant majority of respondents also associate direct printing with higher biocompatibility concerns.

The Fig. 27, 28,29,&30 show the survey data reveals that while aligners are preferred for mild crowding (< 4mm) with standard movements of 0.25mm per stage, their use in complex growing or skeletal cases is highly case-dependent. Practitioners frequently rely on auxiliaries and TADs to manage more difficult scenarios, such as extraction cases

DISCUSSION:

The present study evaluated the awareness, knowledge, and clinical usage of aligners among orthodontic postgraduate students, with a focus on thermoformed and emerging direct 3D printed aligner systems.

1. Demographic Distribution

In this study, the majority of participants were second-year postgraduate students (45.6%), followed by first-year (36%) and third-year students (18.4%). This distribution suggests a relatively balanced representation, although a higher proportion of second-year students may reflect increased clinical exposure during this phase of training.

2. Clinical Usage of Aligners

A key finding of this study was that 81.6% of postgraduate students reported using aligners in clinical practice or training. This indicates a high level of adoption and exposure to aligner therapy among postgraduate students.

This finding is consistent with recent trends in orthodontics, where aligners are increasingly integrated into routine clinical practice due to their esthetic appeal, patient comfort, and digital workflow advantages. The high usage rate also reflects improved accessibility and incorporation of aligner systems into postgraduate training programs.

3. Cost–benefit analysis

Overall, the results indicate that while orthodontic postgraduate students exhibit high awareness and clinical exposure to aligner therapy, cost remains the primary limiting factor, emphasizing the need for cost-effective solutions and greater integration of advanced technologies such as direct 3D printed aligners into clinical training.

4. Preference for Aligner Systems

Among aligner users, Smile Aligners (71.9%) were the most commonly used system, followed by other systems (14.9%), while Invisalign (8.8%) and Spark (4.4%) were less frequently used.

This pattern suggests that cost and accessibility play a significant role in aligner selection, particularly in the Indian context. Locally available aligner systems are more economical and easier to integrate into institutional setups compared to premium international systems.

The lower usage of Invisalign and Spark aligners may be attributed to:

• Higher cost
• Limited institutional access
• Dependence on external laboratories

5. Barriers to Aligner Usage

Among participants who had not used aligners, the primary barrier was cost (88.8%), while only a small proportion (11.2%) reported lack of awareness.

This finding is clinically significant as it indicates that:

• Awareness is not the major issue
• Economic constraints are the dominant limiting factor

This aligns with previous studies suggesting that financial considerations significantly influence treatment modality selection in developing countries.

6. Awareness vs Usage Insight

The low percentage of “lack of awareness” (11.2%) combined with high usage (81.6%) suggests that postgraduate students are well-informed and clinically exposed, but decision-making is influenced by practical constraints rather than knowledge gaps.

7. Implications for 3D Printed Aligners

Although your charts didn’t directly show awareness of 3D printed aligners, based on your study theme, this discussion is important:

• Direct 3D printed aligners are still emerging
• Limited clinical exposure is expected
• Need for curriculum integration and hands-on training

8. Statistical Analysis :

The present study demonstrated that while aligner usage and awareness of direct 3D printed aligners were uniformly distributed across all years of postgraduate training, the choice of aligner system showed a statistically significant variation. This suggests that clinical exposure, institutional protocols, and increasing experience may influence the selection of aligner systems among postgraduate students.

9. Comparison with Literature

The findings of this study are consistent with previous research indicating:

• Increasing adoption of aligner therapy
• Growing importance of digital orthodontics
• Cost as a major limiting factor

However, limited literature exists on direct 3D printed aligners, highlighting the novelty and relevance of the present study.

10. Strengths of the Study

• Focus on emerging technology (3D printed aligners)
• Inclusion of postgraduate students (future practitioners)
• Practical insights into clinical usage

11. Limitations

• Self-reported data (response bias)
• Lack of detailed clinical correlation
• Limited statistical depth (if no cross-tab analysis)
• Unequal distribution across years

12. Clinical Implications

• High readiness for aligner adoption
• Need to reduce cost barriers
• Integration of 3D printing technology in training

Encouragement of in-house aligner fabrication

CONCLUSION

The study demonstrates that orthodontic postgraduate students possess high awareness and clinical exposure to aligner therapy, with cost being the primary limiting factor. While thermoformed aligners are widely used, emerging technologies such as direct 3D printed aligners require greater educational emphasis and clinical integration.

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