The uses of 3-dimensional printing technology in orthodontic offices in North America

Introduction

The purpose of this study was to examine the use of orthodontic 3-dimensional (3D) printing technology in North America and to understand why orthodontists are, or are not, incorporating 3D printing technology in their practices.

Methods

A survey questionnaire was delivered on a secure online platform, RedCap (Case Western Reserve University Clinical and Translational Science Award; no. UL1TR002548). The survey consisted of 14-34 items with branching logic. The association between participant demographics and in-house 3D printing was assessed using a chi-square test of independence.

Results

A total of 518 responses were recorded. The highest number of responses came from respondents in the 36-45-year age group. Most of the respondents were practice owners; 46.9% had 3D printers in their office. Chi-square tests of independence were performed on the data to see which associations existed. The strongest statistical associations with using an in-house 3D printer are seen with patient load, practice type, years since residency, and orthodontist’s position.

Conclusions

Approximately 75% of orthodontists use 3D printing technology in some capacity in North America. Major factors that influenced orthodontists to incorporate 3D printing technology into their office were self-interest and research. Major factors that have prevented orthodontists from not incorporating 3D printing technology into their office were space for equipment/ventilation and digital workflow training deficit. Orthodontists use their 3D printers mostly to make plastic retainers from printed models. The strongest associations with using in-house 3D printers are seen in patient load, practice type, years since residency, and orthodontist position. Increasing patient load and being in private practice increases the likelihood of having a 3D printer.

Highlights

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The survey examined the office characteristics of the 3-dimensional (3D) technology.
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A 34-item survey was created to ask orthodontists about their experience with 3D printing.
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It can be concluded that about 75% of orthodontists use 3D printing technology.

Over the last several decades, technological advancements have shaped orthodontics and dentofacial orthopedics into the effective, innovative field it is today. Three-dimensional (3D) printing has exponentially grown in orthodontics, changing the way many orthodontists structure their offices and perform tooth movement. ^, With the right implementation, 3D printing technology can reduce the number of appointments, laboratory turnaround times, and laboratory fees. Software can be used to repair or modify digital models quickly before printing. Several software programs can also be used to digitally remove brackets and appliances. Thus, an orthodontist can deliver a transpalatal arch the day after an expander is removed or retainers are removed immediately after debonding. When patients lose their retainers, the printed resin models are strong enough to be reused for making replacements. Because this is an emerging advancement in this field and is still in its infancy, it is not fully known to what extent practitioners have implemented or considered making the switch from analog to digital.

In evaluating the use of 3D printing, researchers and clinicians were focused on the accuracy of 3D printed models and the workflow of fabricating clear aligners, retainers, and splints with these printed models using the conventional workflow. However, there is a lack of information on the process of how this technology is implemented and incorporated in the orthodontic office. Therefore, the purpose of this study was to address these knowledge gaps and characterize the users and uses of 3D printing in orthodontic care. The survey seeks to examine the association of demographic factors, training experiences, and office characteristics with the in-office and outsourcing of 3D technology. Furthermore, the study assessed the popularity of software applications for 3D printing.

Material and methods

Statistical analysis

A 34-item survey ( Supplementary Material ) with branching logic was created to ask practicing orthodontists about their experience with 3D printing. The survey asked whether 3D printing applications were in-office, outsourced, or not used; the rationale for why orthodontists incorporate 3D printing technology or not; what type of 3D software is used; and perceptions on the applications, uses, pitfalls, and benefits of 3D printing. In addition, survey items included the number of printers in the office, the procedures for which printers are used, and questions about their 3D laboratory. If the orthodontist does not have a 3D printer in the office, additional questions inquired why not and if they plan to include 3D printers in the future. Finally, personal and office characteristics were collected to describe the respondents and to evaluate potential associations between the use of 3D printing and demographic variables.

The study survey was developed and administered on a secure online research platform called REDCap (Case Western Reserve University Clinical and Translational Science Award; no. UL1TR002548). To reach the widest audience, the survey was distributed using 3 methods. The first method was via the American Association of Orthodontics (AAO) Partners in Research program. The AAO program randomly selected 2200 Partners in Research members to receive a survey link inviting and welcoming them to complete the questionnaire. Only a portion of the AAO membership is sampled for any survey to avoid “survey fatigue” from repeated requests to complete surveys. Respondents who were active orthodontists in the United States and Canada, including orthodontic faculty, were included in the analysis. Retired orthodontists and orthodontic residents were excluded from the study. The second method of survey distribution was through an orthodontic Facebook group called Orthodontic Pearls, with the link placed on the group’s Web site, inviting them to participate. An invitation and the REDCap survey link were provided to interested members. Finally, business cards with quick response codes linked to the REDCap survey were distributed at the American Association of Orthodontists’ in-person meeting in Miami, Florida, in 2022. Because of multiple distribution pathways, respondents were asked not to complete the survey more than once. Because of the large map of the United States included on the first page of the survey, we were confident that respondents would recognize the survey. The data for this study were collected between February 1, 2022 and June 30, 2022, from orthodontists practicing in North America.

The data were analyzed using SPSS software (version 27.0; IBM, Armonk, NY). Descriptive statistics were used to analyze the frequency of responses. Associations between participant demographics and in-office 3D printing were assessed using a chi-square test of independence. A binary logistic regression model was constructed to assess the strength of the association between independent variables and the presence of an in-office printer. Significant variables from the chi-square test were included in the model. Odds ratios and 95% confidence intervals are reported. Statistical significance was defined as P ≤0.05. This study was approved by the Case Western Reserve University Institutional Review Board.

Results

A total of 518 responses were received, and all responses were included in the data analysis. A total of 268 (51.70%) responses came from the Facebook group, followed by 182 (35.10%) responses from the in-person meeting, and 68 (13.1%) responses came from the AAO survey link. The response rate from the AAO link was very low (3%), whereas response rates from the Facebook group and in-person meeting cannot accurately be determined. The highest number of responses came from the 36-45-year age group (32.8%) and from those who have been in practice for >10 years (51.2%). Most respondents were practice owners (60.8%), working in private practice (82.6%), and practicing primarily in a suburban area (62.8%). The greatest number of respondents treat 45-60 patients daily (31.5%).

Approximately 73% of respondents use 3D printing applications in some capacity, whether in-office or outsourced. Over half (53%) of the respondents reported they had training in the use of 3D printing. The most common training method among those with training was reported as self-taught (38.4%), followed by continuing education (28.6%). Among orthodontists with an in-office printer, more than half (53%) have >2 years of experience. Respondents were most often familiar with digital light processing (35.1%).

Among all respondents, 46.9% had a 3D printer in their office; among those, 45.4% had 1 printer, whereas 54.6% had ≥2. Among the clinicians with 3D printers in their office, 57% use both in-office aligners and full-service aligners companies, 16% use only in-office aligners, 13% use only full-service companies for aligners, and 14% do not use aligners therapy. The percentage of respondents with in-office printers from each of the 3 survey methods was 50.4%, 45.1%, and 38.2% for Facebook, in-person meetings, and AAO, respectively. The difference in distribution across the methods was not statistically significant ( P = 0.064). Sprintray (Los Angeles, Calif) was the most owned printer (47.0%), followed by Formlab (Somerville, Mass) (23%) and Anycubic (London, United Kingdom) (14%). Printing models for plastic retainers was the most popular use of a 3D printer in a practitioner’s office (90.9%) ( Fig 1 ) and was also the most common application among outsourced applications for offices without an in-office printer (64.8%). Overall, the most common application of 3D printing technology was for printing in-office and outsourced retainers (81.9%), followed by printing models for in-office aligners (70.6%). The most common reason orthodontists initially incorporated 3D printers in their offices was due to self-initiated research or interest in 3D printing. Practitioners with a 3D printer were very pleased with it, as 96.3% reported it meeting their expectations.