Among the innovations that have changed modern orthodontics, the introduction of new digital technologies in daily clinical practice has had a major impact, in particular the use of 3D models of dental arches. The possibility for direct 3D capture of arches using intraoral scanners has brought many clinicians closer to the digital world. The digital revolution of orthodontic practice requires both hardware components and dedicated software for the analysis of STL models and all other files generated by the digital workflow. However, there are some negative aspects, including the need for the clinician and technicians to learn how to use new software. In this context, we can distinguish two main software types: dedicated software (i.e., developed by orthodontic companies) and open-source software. Dedicated software tend to have a much more user-friendly interface, and be easier to use and more intuitive, due to being designed and developed for a non-expert user, but very high rental or purchase costs are an issue. Therefore, younger clinicians with more extensive digital skills have begun to look with increasing interest at open-source software. The aim of the present study was to present and discuss some of the best-known open-source software for analysis of 3D models and the creation of orthodontic devices: Blue Sky Plan, MeshMixer, ViewBox, and Blender.

Objectives The aim was to assess the diagnostic ability of the crown‐to‐root length ratio of the primary second molar and the position of the corresponding underlying premolar in estimating future anchoring teeth exfoliation during maxillary expansion. Setting and Sample Population Fifty‐four subjects (30 females, 24 males; 108 teeth) aged 8.2 ± 1.0 years that underwent palatal expansion. Methods The upper second premolar position of the corresponding expander anchoring primary molar was determined in relation to the ipsilateral first permanent molar half‐pulp chamber (HPC) line on panoramic radiographs. Subjective and objective (based on measurements) assessments of the crown‐to‐root length ratio of anchoring primary molars were performed. Exfoliation after the expansion was recorded over a retention period of 12 months. All the assessments were performed individually by three examiners at two 3‐week‐apart sessions, trained and calibrated before enrolment. The intra‐/inter‐examiner agreements were evaluated, and the diagnostic accuracy of the methods was calculated. Results All methods exhibited almost perfect intra‐ and at least substantial inter‐examiner agreement (Kappa >0.8 and ≥0.63, respectively). Good diagnostic accuracy was seen for the premolar position to the HPC line (0.7‐0.8), while the crown‐to‐root length ratio methods exhibited hardly sufficient accuracy. The diagnostic agreement of the methods was fair. Conclusions When primary molars are considered as anchoring teeth for maxillary expansion, the premolar position in relation to the HPC line appears to be the most valid and reliable method for predicting their stability. Despite high repeatability values, the crown‐to‐root length ratio needs a cut‐off point re‐definition to increase its predicting ability.

Summary Objectives The aim was to identify factors associated with maxillary expander loss due to anchoring deciduous molars exfoliation and assess the diagnostic accuracy of the upper second premolar cusp position as a prognostic factor for the exfoliation of its corresponding deciduous molar. Materials/methods Ninety-two subjects aged 8.4 ± 1.1 years, treated with a Haas or hyrax expander, and using the same expansion protocol and deciduous teeth as anchorage were included. The position of the upper second premolar cusp, according to the half pulp chamber (HPC) line of the ipsilateral upper first permanent molar, was assessed on pre-treatment panoramic radiographs. Results A significant association between anchoring deciduous molar exfoliation and the position of the upper second premolar cusp according to the HPC line (P = 0.002; odds ratio = 5.7) was seen, while there was no association with gender, age, treatment duration, and type of expander. The median survival time for an anchoring deciduous molar, when the underlying premolar cusp was touching/crossing the HPC line, was 13.0 (11.7; 14.2) months. The upper second premolar cusp position to the HPC line showed high accuracy (at least 76.11 per cent) and substantial repeatability (at least 0.7) as a prognostic factor for the corresponding second deciduous molar exfoliation. Limitations Applicability in the mixed dentition phase with fully erupted upper first permanent molars. Conclusions The probability of a second deciduous molar to be successfully used as maxillary expander anchorage for at least 16 months is above 94 per cent; when at baseline, the corresponding premolar cusp is apical to the HPC line.