Combined use of digital imaging technologies: ortho-surgical treatment

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Article received: 20/11/2017. Accepted for publication: 20/12/2017. Address for correspondence: Laurent Petitpas – 35c impasse des Brasseries – 54700 Pont-à-Mousson E-mail:ortho@petitpas.eu


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Are digital dental impressions able to replace traditional dental impressions? This question haunts many orthodontists who are considering investing in intraoral scanners.
In my opinion, replacing the conventional procedure for taking impressions is not necessarily the most important objective.
In fact, these devices bring a much greater value to our treatments by optimizing and controlling our mechanics, while serving as a precise means of planning, previewing, and evaluating our results.
The presentation of the following complex case shows how the combination of different digital imaging technologies can be useful in difficult cases such as surgical cases.
This patient was seen for temporomandibular joint (TMJ) pain combined with limited mouth opening.
Clinical examination revealed a class II skeletal malocclusion with a very convex hyper-divergent profile combined with a mandibular lateral deviation on the right.
Cephalometric profile analysis shows maxillary proalveolia and skeletal class II. Facial cephalometric analysis revealed a convergence of gonic and occlusal planes, confirming mandibular deviation.
At this point, digital imprinting (3M True Definition Scanner) is used to refine the diagnosis, quantify asymmetries, plan treatment, and visualize objectives.
An earlier magnetic resonance imaging of the TMJ confirms what the clinical examination suggested: a bilateral irreducible meniscal dislocation.    The chosen treatment plan involves a surgical-orthodontic protocol, which begins with the wearing of a mandibular joint orthopedic repositioning gutter to provide patient relief.
The orthodontic preparation is then performed using a fixed, vestibular mandibular, and maxillary lingual technique. The digital impressions having been used again to create the lingual apparatus (Incognito Lingual Appliance System).
In addition to decompensating the malpositions due to lateral deviation, the orthodontic preparation made it possible to reposition the mandible and restore asymptomatic joint conditions. Class II intermaxillary elastics were used to maintain asymmetric joint positioning during this treatment step.
Complete assessment with a digital impression was carried out at the end of the 14-month orthodontic preparation to objectify the results of the orthodontic preparation. Significant improvement was observed. The maxillary arch is now symmetrical, the canine axes corrected, and the Wilson curve balanced.
Moreover, TMJs are now asymptomatic and function properly.
The superimposition of the digital data allows both the visualization of the orthodontically obtained modifications and previsualization of the surgical orthopedic repositioning.
The surgical procedure is planned by combining digital impressions and CbCT scans, thus making it possible to perform a bone set-up.
The surgery is then performed according to the treatment plan.
At the end of the surgery, 4 months of orthodontic finishing allowed the treatment to be completed. A new complete assessment is then conducted to compare the results.

Figure 15
Intraoral pictures after treatment. Centered medians; bilateral dental class I obtained.
Comparison with the initial markers at the start of treatment (see Figure 9).    Additional assessments were performed by combining CbCT with digital models and by superimposing CbCTs before and after surgery.
The effects of the treatment are visible and the changes in the mandible are notable.
Finally, TMJ repositioning was verified.
CoMbInED uSE oF DIgITAL IMAgIng TEChnoLogIES: orTho-SurgICAL TrEATMEnT

Figure 22
Facial changes, especially at the level of the lips. 3D modeling allows better evaluation than 2D.

Figure 23
Thermoformed gutters on PLA models.
The comparison of the two 3D examinations shows that the center of the lower lip has changed significantly and moved 13 mm above and forward with chin alignment.
The finishes were made from digital impressions. The compression gutters were made directly at the practice on models made of polylactic acid (PLA) using a 3D printer.
This clinical case perfectly illustrates the new opportunities offered by the use of digital techniques.
They are a valuable aid for diagnosis, planning, device design, and evaluation of the different treatment stages.
While there are advantages to the individual use of each technique, it is undeniable that their combined use maximizes the benefits that can be derived from it. The fused modeling of teeth, bone bases, and soft tissues results in the creation of a virtual patient.
This approach makes it possible to visualize the treatment plan at any level, both dental and cutaneous.
L. PETITPAS For the orthodontist, it facilitates the early detection of possible treatment plan errors while promoting communication with patients, which is the key to therapeutic success. In the long term, this wealth of information could lead to a better understanding of therapeutic mechanisms and their success.