Quantification of Dental Movements in Orthodontic Follow-Up: A Novel Approach Based on Registration of 3d Models of Dental Casts

Abstract

Introduction: The assessment of dental displacement achieved by orthodontic procedures is important as it allows operators to verify their clinical treatment and provide adequate adjustments. Modern 3D image acquisition and elaboration systems may represent a valid method for the three-dimensional assessment of dental movement. A novel protocol for the 3D assessment of success of orthodontic therapy is proposed, based on registration of surfaces. Methdology: Pairs of casts of the upper dental arch, taken at two different time periods during the therapy, were chosen for three patients who underwent an orthodontic treatment. Dental casts were scanned by a 3D laser scanner: for each patient, the two 3D models were then registered according to the least distance at the area including palatal rugae. The chromatic map of changes within the dental arch and the RMS (Root Mean Square) point-to-point distance between the dental profiles from the two models were obtained, and compared with the same data from a control group including five adult individuals who did not undergo orthodontic therapy. Inter-and intra-observer errors were evaluated as well. Results: The novel procedure proved to be repeatable and gave a detailed description of those dental areas most affected by orthodontic therapy: RMS values seem to be related with the weight of dental modifications and are far higher than the same parameters computed in the control group. Conclusion: Further studies are needed in order to explore the possible correlation of RMS value with clinical parameters linked to the improvement of dental function and aesthetics due to orthodontic therapy.

Soft-Tissue Facial Asymmetry Before and After Orthognathic Surgery: Application of a New 3d Protocol

“…Files can be exported and elaborated with proprietary and custom software. In particular, the Mirror® Vectra Software (Canfield Scientific, Fairfield, NJ, USA) was used in the present investigation [4]. The patient had a diagnosis of skeletal Class III dysmorphism and was a candidate for a surgical intervention of bimaxillary osteotomy.…”

“…Apart from the restoration of a sound functionality and a normal occlusion, aesthetics and facial symmetry are among the most important aspects in modern orthognathic surgery [2]. The successful attainment of an aesthetically acceptable result starts from correct skeletal and dental positions [3][4][5], but it needs a thorough evaluation of the facial soft tissues [1,2]. The external appearance of the face is also the key point for a fruitful dialogue among the surgeons, the orthodontists and the patients, allowing the best compliance especially for treatments that require several interventions, and that need a middle term follow up to show their final results [6,7].…”

Are Dental Measurements Taken on Plaster Casts Comparable to Those Taken From CBCT Images and Laser Scanned Surfaces?

“…Among the other applications, these devices can replace dental plaster casts with digital models possessing several advantages: easy storage, no necessary physical space, no damages during handling, and easy data share with other professionals [1][2][3][4][5][6][7][8][9]. CBCT, in particular, gives a 3D representation of the cranio-facial and dental structures and has already several indications in clinical routine: oral and maxillofacial surgery (orthognathic surgery, treatment of traumas and malignancies, nerve tracing in cases of third molar extraction and implant placement), endodontics (root fracture detection), orthodontics (diagnosis and treatment planning) [6,[10][11][12][13][14][15].…”