## 4 Discussion  
This case series analyzed 10 patients who had lost lower first molars and presented mesialization of the second molar. The study objectives were to measure the changes in angulation and the prosthetic space gained as a result of miniscrew mechanics using standardized pre- and post-treatment orthopantomographs. The same radiological technique has been used in other study by [PERSON] et al. [23], the latter complemented by lateral teleradiography of the cranium in order to perform cephalometric analysis. Standardized radiographs are frequently used in dental research for a range of purposes. After scaling the radiographs, the images obtained were processed using software to take measurements of changes in the prosthetic space available and angulation, as described by [PERSON] et al. [24], [PERSON] et al. [25], [PERSON] et al. [26], and [PERSON] et al. [27; 28], who used various software functions for purposes similar to the present work. Measurements were taken using the same method in all cases. Angulation was analyzed by tracing a line along the vertical axes of the premolar and the second molar, afterwards tracing a line parallel to the premolar axis passing though the second molar furcation. To measure increases in prosthetic space, the distance between the most distal point of the premolar crown and the most mesial point on the second molar was measured. No other study in the literature has measured both angulation and prosthetic space together. All ten cases were treated by means of the same technique. A miniscrew was inserted in the retromolar area, placing a button on the mesial or the vestibular aspect of the second molar crown; the same technique has been described in several other studies [23; 29; 30; 31; 32]. The literature includes several works that describe miniscrews placed in mesial areas with the same objective as the present case series [23; 29]. Although the use of miniscrews in retromolar areas is common, soft tissue thickness and the patient's oral health must be assessed in order to select the most suitable position to ensure a successful outcome. According to the present results, the first hypothesis (H\({}_{1}\)) may be accepted, as it was found that the use of a miniscrew in the retromolar area and a mesial button on the crown straightened the second molar significantly (\(p=0.005\)). Figure 4: Prosthetic space gained in relation to reductions in angulation. In all the cases included in this clinical series, sufficient prosthetic space was gained to allow replacement of the missing molar with an implant-supported single crown. The space gained was also statistically significant (\(p=0.005\)). Although other studies do not provide actual data regarding the prosthetic space gained, they do report sufficient gains to allow replacement of the missing tooth with an implant [23; 30; 33]. Meanwhile, [PERSON] et al. [29], after straightening the mesialized tooth, closed the space by means of conventional orthodontic movement. [PERSON] et al. [23] state that treatment obtained sufficient space to replace the missing tooth although they do not specify the rehabilitation provided. The second hypothesis (H\({}_{2}\)) that miniscrews would produce enough prosthetic space to replace the first molar may also be accepted. There are many techniques for molar uprighting, such as: Australian uprighting spring, cantilever spring, prefabricated Sander spring, helical uprighting spring, NiTi coil spring, push spring appliance, or orthodontic miniscrew implants, among others [34]. Molar uprighting requires good anchorage control, and conventional treatment methods have some disadvantages: a full arch fixed appliance is necessary to minimize the extrusion of the target molar and the reciprocal movement of the anchorage units; spring designs require complex mechanics and may cause tissue irritation to the patient [35]; in addition, longer treatment time and bulky appliances are needed.