A novel method for fabricating nasoalveolar molding appliances for infants with cleft lip and palate using 3-dimensional workflow and clear aligners



A novel method for fabricating nasoalveolar molding appliances for infants with cleft lip and palate using 3-dimensional workflow and clear aligners




American Journal of Orthodontics and Dentofacial Orthopedics, 2020-09-01, Volume 158, Issue 3, Pages 452-458, Copyright © 2020 American Association of Orthodontists


Introduction

Nasoalveolar molding (NAM) was introduced over 20 years ago as adjunctive therapy for the correction of cleft lip and palate. In the current study, we propose a new approach using a digital workflow and 3-dimensional printing to fabricate clear aligner NAM devices.

Methods

A polyvinyl siloxane (PVS) impression of an infant with a unilateral complete cleft lip and palate (UCLP) is acquired and poured, and the stone model is scanned with an intraoral scanner. The stereolithography file is digitized, and the alveolar segments are digitally segmented and moved to the desired final position. The total distance moved is divided into a sequence of 1-1.5 mm increments, creating a series of digital models. The models are 3-dimensionally printed along with button templates to allow free form positioning of the button on each model. A Vacuform machine (Taglus, Mumbai, India) was used to fabricate a 0.040-in aligner for each stage.

Results

We present 1 case that was treated successfully with this approach. Appointments for the NAM adjustments were primarily to monitor progress and counseling with less time spent adjusting the appliance. The appointment length was reduced by over 30 minutes. Benefits of the aligner are improved fit, more precise increments of activation, reduced chairside time, and potentially minimized number of visits.

Conclusions

NAM custom aligners may provide similar benefits to the traditional approach while reducing the burden of care by reducing the number of visits and appointment duration. Further studies with a sample and longitudinal observations are needed to investigate the benefits of the proposed digital approach.

Graphical abstract

Highlights

  • Nasoalveolar molding (NAM) appliances can be used in neonates with cleft lip and palate.

  • A novel method is presented for fabricating NAM appliances from clear aligners.

  • The method uses computer-aided design and computer-aided manufacturing.

  • NAM aligners are a promising approach for reducing the burden of care.

Cleft lip and/or palate is the most common craniofacial condition, with an incidence rate of about 1 in 700 births in the United States. Presurgical Infant Orthopedics (PSIO) appliances have been used since the 1950s as an adjunctive neonatal therapy for the correction of cleft lip and palate. The objective of these therapies is to help approximate the segments, with the goal of reducing the defect size, and simplifying the surgical procedure and minimize scarring. The biologic basis for the efficacy of PSIO is based on the high degree of plasticity in the cartilage of neonates because of transient high levels of estrogen and hyaluronic acid. Since their introduction, many PSIO techniques have been described in the literature. , , In the early 1990s, Grayson introduced nasoalveolar molding (NAM) therapy. Traditionally, NAM appliances are made of a removable alveolar molding plate, to which a nasal stent is added, that is worn in conjunction with lip taping. The nasal stent and the molding plate are adjusted weekly for 10-16 weeks to gradually correct the nasal and alveolar deformities until the infant is ready for surgical repair. The objectives of NAM are to approximate the lips and alveolar segments, improve the symmetry of the nasal cartilages and provide a nonsurgical elongation of the columella. ,

A recent study showed that nearly 50% of cleft centers in the United States offer NAM therapy. Despite the advantages of NAM therapy, a major concern is the considerable burden of care associated with the number of visits required, distance traveled for adjustments, visit duration, and the cost of treatment, which may reduce the likelihood of adhering to the treatment protocol.

Over the last decade, digital imaging technology, such as computer-aided design (CAD), computer-aided manufacturing (CAM), and 3-dimensional (3D) printing, has gained wide popularity in the medical field, with reports of a wide range of clinical applications that were shown to facilitate and improve clinical outcomes. , More recently, investigators have reported successful usage of 3D technologies to aid with the fabrication of NAM appliances.

In the current manuscript, we propose a novel method for using CAD and/or CAM technologies to simulate the desired movements, 3D print the models, and then fabricate a series of NAM appliances using thermoplastic clear aligners in a single step. Our goal was to reduce the burden of care, minimize clinician chair time, and facilitate the process for the clinician and the infant's family.


Material and methods

We present a new method for fabricating NAM appliances using 3D planning and 3D printing, along with clear thermoplastic aligners. The first step was acquiring a traditional impression using Sil-tech (Ivoclar Vivadent, Amherst, NY) matrix putty material in a hospital setting, to allow for rapid response by an airway team in the event of an emergency. The impression is then poured, and the stone model is scanned with an intraoral scanner. The resultant stereolithography file is imported into Ortho Insight 3D software (MotionView Software, Chattanooga, Tenn) ( Fig 1 , A ). The alveolar segments are digitally segmented and moved to the desired final position ( Fig 1 , B and C ; See Video , available at www.ajodo.org ). The segmentation is done by manually placing a point on the most anterior and most posterior points of each segment, resulting in an approximate perimeter surrounding the segment, which is then manually adjusted by the operator to ensure the inclusion of the whole segment. However, depending on the case, the operator may choose to split the greater segment further into 2 segments, if more rotational control is needed for the anterior portion of the greater segment (See Video , available at www.ajodo.org ). The final position is set by the operator, and the goal is to approximate the segments to the estimated position of the midline ( Fig 1 , B and C ; See Video , available at www.ajodo.org ). The movement, as shown in the Video (See Video , available at www.ajodo.org ), can be tailored by the operator to each case. The total distance moved was divided into a sequence of 1-1.5 mm increments, allowing us to create a sequence of digital models ( Fig 1 , D ). The total movements were divided evenly among the number of stages, as the software allows us to perform the entire movement, choose the number of stages and then automatically evenly distribute the movements over the number of stages. The increments of activation were determined by the operator on the basis of previous recommendations from the literature. Subsequently, the staged models are 3D printed ( Fig 1 , E ).

The digital workflow for designing and fabricating NAM aligners: A, the scanned model is imported into MotionView Software (MotionView Software, Chattanooga, Tenn); B, the alveolar segments are digitally segmented; C, the alveolar segments are moved into the desired final position; D, the total distance moved was divided into a sequence of 1-2 mm increments, allowing us to create a sequence of digital models; E, the staged models are 3D printed; F, a button template is 3D printed and attached to the printed model at each stage; G, a Vacuform machine is used to fabricate an 0.040-in aligner for each stage; H, the button is retained in the aligner and easily separates from the model, after which the aligner is trimmed and smoothened for comfort; I, the nose piece is added to the aligner at the desired stage with a 0.030-in orthodontic wire and Triad is added for nasal support. Triad and Assure Plus are used to adhere the nasal support wire to the aligner, with retention holes cut out for increased retention. ∗ Done at each stage. § Done at the desired stage (in the presented example, stage 6).
Fig 1
The digital workflow for designing and fabricating NAM aligners:
A, the scanned model is imported into MotionView Software (MotionView Software, Chattanooga, Tenn);
B, the alveolar segments are digitally segmented;
C, the alveolar segments are moved into the desired final position;
D, the total distance moved was divided into a sequence of 1-2 mm increments, allowing us to create a sequence of digital models;
E, the staged models are 3D printed;
F, a button template is 3D printed and attached to the printed model at each stage;
G, a Vacuform machine is used to fabricate an 0.040-in aligner for each stage;
H, the button is retained in the aligner and easily separates from the model, after which the aligner is trimmed and smoothened for comfort;
I, the nose piece is added to the aligner at the desired stage with a 0.030-in orthodontic wire and Triad is added for nasal support. Triad and Assure Plus are used to adhere the nasal support wire to the aligner, with retention holes cut out for increased retention.
Done at each stage.
§ Done at the desired stage (in the presented example, stage 6).

We used a Fused filament fabrication (FFF) printer, Monoprice Ultimaker (Monoprice, Rancho Cucamonga, Calif), with high-temperature polylactic acid filament to allow for the fabrication of NAM aligners with thermoplastic clear aligner material. When the models are printed, a button template is also printed to allow free form positioning of the button for each patient. The button is added directly to the model and attached using light cure Triad gel (Dentsply Sirona, Charlotte, NC) ( Fig 1 , F ). Once the button is placed, a Vacuform machine is used to fabricate an 0.040-in aligner (Taglus, Mumbai, India) for each stage ( Fig 1 , G ). The button is retained in the aligner and easily separates from the model, after which the aligner is trimmed and smoothened for comfort, and the edges were polished with a polishing wheel ( Fig 1 , H ). The nose piece is added to the aligner at the desired stage with a 0.030-in orthodontic wire, and Triad is added for nasal support. Triad and Assure Plus (Reliance Orthodontic Products, Itasca, Ill) are used to adhere the nasal support wire to the aligner, with retention holes cut out for increased retention ( Fig 1 , I ).

One male infant with an 8 mm left unilateral cleft lip and palate was treated with digitally designed clear aligner NAM appliances. The patient was aged 21 days at the start of treatment ( Fig 2 ). A total of 6 aligners were fabricated, and the nose piece was added to the last stage. The appliance was fabricated, as mentioned above, with most of the movement designed to target the minor segment of the alveolus because the major segment was well-aligned ( Fig 1 ; See Video , available at www.ajodo.org ). The total number of visits was 11, and the total treatment duration was 14 weeks until the cheiloplasty was performed. The Table describes the patient and treatment process. In our study, the infant's NAM treatment was simulated, and the appliances were constructed on the basis of the simulation, as described above. At the initial impression visit, taping with elastics was applied and reviewed with the parents ( Fig 2 ). Taping continued throughout treatment after delivery of the appliance, in which the tape and elastics were attached to the molding aligner ( Fig 3 ). The nose piece was added to the last aligner only, which was possible in this case because there was sufficient time between the last aligner stage and the lip repair surgery. Figure 3 illustrates the appliance in place at the final stage with the nose piece and the fit of the appliance intraorally.

Initial pictures of the infant taken at the first visit. The taping approach is shown, along with the defect size. The collapse of the nasal base is evident. The initial model shows the size of the defect (8 mm).
Fig 2
Initial pictures of the infant taken at the first visit. The taping approach is shown, along with the defect size. The collapse of the nasal base is evident. The initial model shows the size of the defect (8 mm).

Table
Description of the patient and treatment process
Parameter Description
Cleft side Left
Cleft size, mm 8
Age at starting NAM, d 21
Total number of aligners, n 6
Stage of adding nose piece, n 6
Total treatment duration, wk
Active NAM 6
Passive NAM, with only nose piece adjustment 8
Total 14
Total number of visits (including screening and impression visits) 11
Complications Mild gingival irritation at stage 5 relieved by trimming plastic

Pictures of the infant at the end of NAM aligner treatment, after 14 weeks. Taping to the appliance is shown, along with the intraoral fit of the appliance. The elevation of the nasal base is evident on the affected side. The final model shows complete closure of the defect.
Fig 3
Pictures of the infant at the end of NAM aligner treatment, after 14 weeks. Taping to the appliance is shown, along with the intraoral fit of the appliance. The elevation of the nasal base is evident on the affected side. The final model shows complete closure of the defect.


Results

Figure 3 shows the infant at the end of treatment and the final model, and the Table describes the treatment process. Figure 4 shows the initial and final models and the best-fit 3D superimposition of the models. The defect was completely closed with the 6 aligners with acceptable results. We noticed that the final model did not completely resemble the simulation because the minor segment was slightly displaced mesially. However, it is important to note that the best-fit superimposition of a nonstable alveolus of an infant may not present a very accurate representation of the movements, but rather shows an approximate evaluation of the changes that happened during treatment. Overall, the treatment process achieved the desired results, and there was no need for additional impressions ( Fig 4 ). The time required for digitally designing and fabricating the whole series of aligners ranged from 2 to 3 hours (excluding printing time). Designing the appliance, digitally, takes 15-30 minutes, and the rest of the fabrication time, which may be delegated to a technician, is focused on placing the buttons, creating the aligners, and trimming them. The initial appointment and adjustment and trimming of the appliance take approximately 30 minutes to maximize vestibular extension and review with the parents the placement and removal of the appliance and answer questions regarding NAM treatment. Try in and fit verification appointments required less than 10 minutes. The placement of the nose piece requires additional time because it needs to be adjusted to the particular child and requires approximately 30 minutes. By the end of NAM aligner treatment, the deformity of the nose was reduced, and the cleft gap was abridged, with the alveolar segments and vermillion borders almost touching, whereas an improved maxillary alveolar arch form was achieved ( Fig 3 ). 3D best-fit superimposition of the initial and final models showed that most of the movement was focused on the minor segment as planned, although the lesser segment slightly collapsed mesially, presumably because of forces exerted from the taping ( Fig 4 ).

A, The initial model. B, The predicted and/or simulated final result. C, The final model. The defect was completely closed with the 6 aligners with acceptable results. We noticed that the final model did not completely resemble the simulation because the minor segment was slightly displaced mesially. D, Initial and final models, and best-fit 3D superimposition of the models.
Fig 4
A, The initial model.
B, The predicted and/or simulated final result.
C, The final model. The defect was completely closed with the 6 aligners with acceptable results. We noticed that the final model did not completely resemble the simulation because the minor segment was slightly displaced mesially.
D, Initial and final models, and best-fit 3D superimposition of the models.

Benefits of the aligner are improved fit at each stage, transparent, visual appreciation of blanching tissue allows for verification of active vs passive fit of appliance ( Fig 3 ), more precise increments of activation, reduced time in office for patient and parents, and extended time between a visit with good compliance. With the new NAM aligner, most of the time during appointments was focused on nutrition and counseling vs actual adjustment of the appliance.


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A novel method for fabricating nasoalveolar molding appliances for infants with cleft lip and palate using 3-dimensional workflow and clear aligners Rany M. Bous , Nicholas Kochenour and Manish Valiathan American Journal of Orthodontics and Dentofacial Orthopedics, 2020-09-01, Volume 158, Issue 3, Pages 452-458, Copyright © 2020 American Association of Orthodontists Introduction Nasoalveolar molding (NAM) was introduced over 20 years ago as adjunctive therapy for the correction of cleft lip and palate. In the current study, we propose a new approach using a digital workflow and 3-dimensional printing to fabricate clear aligner NAM devices. Methods A polyvinyl siloxane (PVS) impression of an infant with a unilateral complete cleft lip and palate (UCLP) is acquired and poured, and the stone model is scanned with an intraoral scanner. The stereolithography file is digitized, and the alveolar segments are digitally segmented and moved to the desired final position. The total distance moved is divided into a sequence of 1-1.5 mm increments, creating a series of digital models. The models are 3-dimensionally printed along with button templates to allow free form positioning of the button on each model. A Vacuform machine (Taglus, Mumbai, India) was used to fabricate a 0.040-in aligner for each stage. Results We present 1 case that was treated successfully with this approach. Appointments for the NAM adjustments were primarily to monitor progress and counseling with less time spent adjusting the appliance. The appointment length was reduced by over 30 minutes. Benefits of the aligner are improved fit, more precise increments of activation, reduced chairside time, and potentially minimized number of visits. Conclusions NAM custom aligners may provide similar benefits to the traditional approach while reducing the burden of care by reducing the number of visits and appointment duration. Further studies with a sample and longitudinal observations are needed to investigate the benefits of the proposed digital approach. Graphical abstract Highlights Nasoalveolar molding (NAM) appliances can be used in neonates with cleft lip and palate. A novel method is presented for fabricating NAM appliances from clear aligners. The method uses computer-aided design and computer-aided manufacturing. NAM aligners are a promising approach for reducing the burden of care. Cleft lip and/or palate is the most common craniofacial condition, with an incidence rate of about 1 in 700 births in the United States. Presurgical Infant Orthopedics (PSIO) appliances have been used since the 1950s as an adjunctive neonatal therapy for the correction of cleft lip and palate. The objective of these therapies is to help approximate the segments, with the goal of reducing the defect size, and simplifying the surgical procedure and minimize scarring. The biologic basis for the efficacy of PSIO is based on the high degree of plasticity in the cartilage of neonates because of transient high levels of estrogen and hyaluronic acid. Since their introduction, many PSIO techniques have been described in the literature. , , In the early 1990s, Grayson introduced nasoalveolar molding (NAM) therapy. Traditionally, NAM appliances are made of a removable alveolar molding plate, to which a nasal stent is added, that is worn in conjunction with lip taping. The nasal stent and the molding plate are adjusted weekly for 10-16 weeks to gradually correct the nasal and alveolar deformities until the infant is ready for surgical repair. The objectives of NAM are to approximate the lips and alveolar segments, improve the symmetry of the nasal cartilages and provide a nonsurgical elongation of the columella. , A recent study showed that nearly 50% of cleft centers in the United States offer NAM therapy. Despite the advantages of NAM therapy, a major concern is the considerable burden of care associated with the number of visits required, distance traveled for adjustments, visit duration, and the cost of treatment, which may reduce the likelihood of adhering to the treatment protocol. Over the last decade, digital imaging technology, such as computer-aided design (CAD), computer-aided manufacturing (CAM), and 3-dimensional (3D) printing, has gained wide popularity in the medical field, with reports of a wide range of clinical applications that were shown to facilitate and improve clinical outcomes. , More recently, investigators have reported successful usage of 3D technologies to aid with the fabrication of NAM appliances. In the current manuscript, we propose a novel method for using CAD and/or CAM technologies to simulate the desired movements, 3D print the models, and then fabricate a series of NAM appliances using thermoplastic clear aligners in a single step. Our goal was to reduce the burden of care, minimize clinician chair time, and facilitate the process for the clinician and the infant's family. Material and methods We present a new method for fabricating NAM appliances using 3D planning and 3D printing, along with clear thermoplastic aligners. The first step was acquiring a traditional impression using Sil-tech (Ivoclar Vivadent, Amherst, NY) matrix putty material in a hospital setting, to allow for rapid response by an airway team in the event of an emergency. The impression is then poured, and the stone model is scanned with an intraoral scanner. The resultant stereolithography file is imported into Ortho Insight 3D software (MotionView Software, Chattanooga, Tenn) ( Fig 1 , A ). The alveolar segments are digitally segmented and moved to the desired final position ( Fig 1 , B and C ; See Video , available at www.ajodo.org ). The segmentation is done by manually placing a point on the most anterior and most posterior points of each segment, resulting in an approximate perimeter surrounding the segment, which is then manually adjusted by the operator to ensure the inclusion of the whole segment. However, depending on the case, the operator may choose to split the greater segment further into 2 segments, if more rotational control is needed for the anterior portion of the greater segment (See Video , available at www.ajodo.org ). The final position is set by the operator, and the goal is to approximate the segments to the estimated position of the midline ( Fig 1 , B and C ; See Video , available at www.ajodo.org ). The movement, as shown in the Video (See Video , available at www.ajodo.org ), can be tailored by the operator to each case. The total distance moved was divided into a sequence of 1-1.5 mm increments, allowing us to create a sequence of digital models ( Fig 1 , D ). The total movements were divided evenly among the number of stages, as the software allows us to perform the entire movement, choose the number of stages and then automatically evenly distribute the movements over the number of stages. The increments of activation were determined by the operator on the basis of previous recommendations from the literature. Subsequently, the staged models are 3D printed ( Fig 1 , E ). Fig 1 The digital workflow for designing and fabricating NAM aligners: A, the scanned model is imported into MotionView Software (MotionView Software, Chattanooga, Tenn); B, the alveolar segments are digitally segmented; C, the alveolar segments are moved into the desired final position; D, the total distance moved was divided into a sequence of 1-2 mm increments, allowing us to create a sequence of digital models; E, the staged models are 3D printed; F, a button template is 3D printed and attached to the printed model at each stage; G, a Vacuform machine is used to fabricate an 0.040-in aligner for each stage; H, the button is retained in the aligner and easily separates from the model, after which the aligner is trimmed and smoothened for comfort; I, the nose piece is added to the aligner at the desired stage with a 0.030-in orthodontic wire and Triad is added for nasal support. Triad and Assure Plus are used to adhere the nasal support wire to the aligner, with retention holes cut out for increased retention. ∗ Done at each stage. § Done at the desired stage (in the presented example, stage 6). We used a Fused filament fabrication (FFF) printer, Monoprice Ultimaker (Monoprice, Rancho Cucamonga, Calif), with high-temperature polylactic acid filament to allow for the fabrication of NAM aligners with thermoplastic clear aligner material. When the models are printed, a button template is also printed to allow free form positioning of the button for each patient. The button is added directly to the model and attached using light cure Triad gel (Dentsply Sirona, Charlotte, NC) ( Fig 1 , F ). Once the button is placed, a Vacuform machine is used to fabricate an 0.040-in aligner (Taglus, Mumbai, India) for each stage ( Fig 1 , G ). The button is retained in the aligner and easily separates from the model, after which the aligner is trimmed and smoothened for comfort, and the edges were polished with a polishing wheel ( Fig 1 , H ). The nose piece is added to the aligner at the desired stage with a 0.030-in orthodontic wire, and Triad is added for nasal support. Triad and Assure Plus (Reliance Orthodontic Products, Itasca, Ill) are used to adhere the nasal support wire to the aligner, with retention holes cut out for increased retention ( Fig 1 , I ). One male infant with an 8 mm left unilateral cleft lip and palate was treated with digitally designed clear aligner NAM appliances. The patient was aged 21 days at the start of treatment ( Fig 2 ). A total of 6 aligners were fabricated, and the nose piece was added to the last stage. The appliance was fabricated, as mentioned above, with most of the movement designed to target the minor segment of the alveolus because the major segment was well-aligned ( Fig 1 ; See Video , available at www.ajodo.org ). The total number of visits was 11, and the total treatment duration was 14 weeks until the cheiloplasty was performed. The Table describes the patient and treatment process. In our study, the infant's NAM treatment was simulated, and the appliances were constructed on the basis of the simulation, as described above. At the initial impression visit, taping with elastics was applied and reviewed with the parents ( Fig 2 ). Taping continued throughout treatment after delivery of the appliance, in which the tape and elastics were attached to the molding aligner ( Fig 3 ). The nose piece was added to the last aligner only, which was possible in this case because there was sufficient time between the last aligner stage and the lip repair surgery. Figure 3 illustrates the appliance in place at the final stage with the nose piece and the fit of the appliance intraorally. Fig 2 Initial pictures of the infant taken at the first visit. The taping approach is shown, along with the defect size. The collapse of the nasal base is evident. The initial model shows the size of the defect (8 mm). Table Description of the patient and treatment process Parameter Description Cleft side Left Cleft size, mm 8 Age at starting NAM, d 21 Total number of aligners, n 6 Stage of adding nose piece, n 6 Total treatment duration, wk Active NAM 6 Passive NAM, with only nose piece adjustment 8 Total 14 Total number of visits (including screening and impression visits) 11 Complications Mild gingival irritation at stage 5 relieved by trimming plastic Fig 3 Pictures of the infant at the end of NAM aligner treatment, after 14 weeks. Taping to the appliance is shown, along with the intraoral fit of the appliance. The elevation of the nasal base is evident on the affected side. The final model shows complete closure of the defect. Results Figure 3 shows the infant at the end of treatment and the final model, and the Table describes the treatment process. Figure 4 shows the initial and final models and the best-fit 3D superimposition of the models. The defect was completely closed with the 6 aligners with acceptable results. We noticed that the final model did not completely resemble the simulation because the minor segment was slightly displaced mesially. However, it is important to note that the best-fit superimposition of a nonstable alveolus of an infant may not present a very accurate representation of the movements, but rather shows an approximate evaluation of the changes that happened during treatment. Overall, the treatment process achieved the desired results, and there was no need for additional impressions ( Fig 4 ). The time required for digitally designing and fabricating the whole series of aligners ranged from 2 to 3 hours (excluding printing time). Designing the appliance, digitally, takes 15-30 minutes, and the rest of the fabrication time, which may be delegated to a technician, is focused on placing the buttons, creating the aligners, and trimming them. The initial appointment and adjustment and trimming of the appliance take approximately 30 minutes to maximize vestibular extension and review with the parents the placement and removal of the appliance and answer questions regarding NAM treatment. Try in and fit verification appointments required less than 10 minutes. The placement of the nose piece requires additional time because it needs to be adjusted to the particular child and requires approximately 30 minutes. By the end of NAM aligner treatment, the deformity of the nose was reduced, and the cleft gap was abridged, with the alveolar segments and vermillion borders almost touching, whereas an improved maxillary alveolar arch form was achieved ( Fig 3 ). 3D best-fit superimposition of the initial and final models showed that most of the movement was focused on the minor segment as planned, although the lesser segment slightly collapsed mesially, presumably because of forces exerted from the taping ( Fig 4 ). Fig 4 A, The initial model. B, The predicted and/or simulated final result. C, The final model. The defect was completely closed with the 6 aligners with acceptable results. We noticed that the final model did not completely resemble the simulation because the minor segment was slightly displaced mesially. D, Initial and final models, and best-fit 3D superimposition of the models. Benefits of the aligner are improved fit at each stage, transparent, visual appreciation of blanching tissue allows for verification of active vs passive fit of appliance ( Fig 3 ), more precise increments of activation, reduced time in office for patient and parents, and extended time between a visit with good compliance. With the new NAM aligner, most of the time during appointments was focused on nutrition and counseling vs actual adjustment of the appliance. Discussion Since the introduction of NAM therapy by Grayson in the early 1990s, many cleft centers have adopted NAM as a beneficial adjunctive therapy for the treatment of patients with cleft lip and palate. , However, traditional NAM techniques may impose a significant burden of care for families. , , We present a new method for using clear aligners and 3D planning for providing NAM therapy while reducing the burden of care. The treatment results were favorable and complete closure of the defect was achieved ( Fig 4 ). However, we noticed that the minor segment was displaced more mesially than the initial simulation, which can be explained by the force imposed from the tape on the minor segment. Such collapse may be less apparent with traditional NAM appliances because of the difference between the thickness of the acrylic trays and that of the aligners. Although using thicker aligners may provide superior support to the segment in the transverse dimension, we believe that overexpanding the minor segment buccally in the setup may be a better approach to compensate for this external force while maintaining the comfort and improved fit of the 0.04-in aligner trays. Digitally designing NAM appliances may offer the benefits of an improved fit and precise design of the expected movement distance and rotation angle of the alveolar segments at each stage. In addition, using clear aligners offers a superior visual appreciation of the soft tissues to assess blanching and sore spots. The authors believe that the greatest benefit of the proposed approach lies in minimizing the burden of care by reducing the visit time by approximately 20-30 minutes and the potential to reduce the number of total visits needed in half or more depending on compliance. Patients undergoing traditional NAM therapy require an average of 14 clinic visits until completion of treatment. Investigators had found that in the United States, patients travel on average over 60 miles to attend their NAM visits. , , This relatively large distance traveled weekly for appointments may impose a significant burden of care and increased costs and may affect adherence to treatment. Using NAM aligners, the clinician may be able to provide multiple NAM appliances at once and instruct the parents to change them weekly, allowing a reduction in the frequency of visits. Traditionally, NAM visits are often longer than 30 minutes and may extend beyond 90 minutes per visit. This increased visit duration and chairside time may inconvenience the family and increase the overall costs associated with NAM therapy. The ability to digitally design and fabricate the appliances ahead of time allows the clinician to minimize the visit length and have the visits more focused on evaluating the progress of treatment, counseling the family, and answering questions, rather than adjusting the appliance. The total time and cost to design and fabricate the appliance is reduced in comparison with the traditional method. Moreover, the level of clinical expertise needed may not be as critical in fabricating NAM aligners, because most of the planning and designing is made on the computer, instead of chairside. Another benefit of NAM aligners is that, if the appliance is lost or broken, a new appliance could be easily fabricated by the clinician without requiring additional impressions or model capturing. More recently, researchers have developed methods to use CAD and/or CAM technologies to engineer NAM appliances. Shen et al used a very similar approach to ours, but they used traditional acrylic to fabricate the appliance on the 3D printed models instead of using clear aligners. Fabricating clear aligners may be less time-consuming than using acrylic, and may offer the added benefits of an improved fit and visual appreciation of the soft tissues. Other researchers included digital additive and/or removal processes and 3D printing of the actual molding plate. , , , Ritschl et al compared the effectiveness of 3D NAM appliances to traditional NAM appliances and concluded that the 2 methods were equally effective. Although the approach and benefits of such approaches resemble ours in various ways, the difference is that we 3D printed the designed models and then fabricated clear aligners instead of printing the actual plate. Because 3D printed plates are not FDA approved in the United States for intraoral use in infants, we modified this approach and opted to use clear aligners to achieve a minimal fabrication time while maintaining the benefits of CAD systems. Future studies are needed to compare the 2 methods in regard to the fit of the appliance, and the benefits of the clear aligners in terms of its potentially superior ability to visualize the soft tissue. The current approach may have some limitations as well and requires further modifications before achieving its full potential. One limitation is the associated costs of software and 3D printers, which may not be readily available at all centers. Cost-benefit analyses may need to be performed to determine the cost-effectiveness of the current approach before it can be widely used. Another limitation is that the nose piece is still added manually, which may be time-consuming. To overcome this limitation, Zheng et al suggested using a split-design 3D printed NAM appliance with an independent nasal hook. However, we opted to add the nose piece only to the last aligner in this case, because we had sufficient time between the last aligner stage and the lip repair surgery. Other patients with larger defect size may necessitate the addition of the nose piece to multiple aligners to allow adequate time for nasal molding before the lip repair. Future efforts may focus on developing methods to digitally incorporate the nose piece into the digital design and fabrication of NAM aligners. In addition, the impression capturing was still done manually using Sil-tech matrix putty material in a hospital setting and then scanned. Ideally, capturing a digital intraoral scan of the infant would save more time, minimize the potential associated risks of traditional impressions, and eliminate the need to capture them in a hospital setting. Intraoral scanners and the associated software, however, are primarily designed for use in older dentulous patients with normal anatomy and possess relatively large scanning sensors, which makes it challenging to capture the maxillary anatomy of a neonate with a cleft. Future developments in intraoral scanners may provide us with smaller sensors and software more suitable for capturing the anatomy of an infant with a cleft, allowing us to digitize the process of NAM therapy fully. We used an FFF 3D printer with a high-temperature polylactic acid filament to print the staged models for aligner fabrication, which produced very acceptable results. However, we noticed minimal amounts of warping when we fabricated one of the aligners, which was caused by the heat produced from the Vacuform machine. Perhaps using stereolithography resin 3D printers would yield more predictable results, because of their higher resistance to heat in comparison with FFF printers. A limitation of this study was the lack of an objective measure of the reduction of the soft tissue lip and nasal deformities, although the figures display an improvement that can be appreciated subjectively. Chou et al have demonstrated the benefits of using 3D stereophotogrammetry to allow for objective evaluations of the results of traditional NAM therapy, a tool that could be used in future studies concerning NAM aligners. Besides the promising clinical advantages of NAM aligners, the usage of 3D technologies in NAM therapy may offer an array of additional benefits. The ability to design a virtual setup of NAM appliances may offer a more visually enhanced approach to teaching clinicians about NAM fabrication and would allow a much better understanding of the procedure, with the ability to train on virtual models. Using CAD and/or CAM offers possibilities for telemedicine and for training and guiding clinicians overseas and at remote locations, who may lack access to specialized training programs or craniofacial teams. Virtual setups would also enhance communication with the families and other practitioners, allowing them to visualize the projected final treatment outcome, and reinforcing their compliance with the therapy. Finally, fabricating NAM appliances for infants with more complex anatomies may be better managed and analyzed with CAD and/or CAM technology, and the movement of the alveolar segments can be better controlled and manipulated in 3 dimensions, allowing more precise movements. Although this methodology is promising and can produce an accurate outcome, this report is only a preliminary proof of concept. Future studies are needed to evaluate the long-term outcome of NAM aligners with large sample sizes, evaluate possible complications and pitfalls, gather feedback from parents and surgeons, and try its application in infants with bilateral cleft lip and palate. Conclusions NAM aligners may save on average 20-30 minutes per appointment and can reduce the number of total visits needed by half or more depending on compliance. The appointments become more focused on our feeding team and counseling the family, instead of the time-consuming adjustment of the traditional appliances. NAM aligners may provide similar benefits to the traditional approach while reducing the burden of care. Future longitudinal studies with a sample are needed to confirm the benefits of NAM aligners. 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