Alveolar bone changes after molar protraction in young adults with missing mandibular second premolars or first molars

Abstract

Objectives To assess the changes in alveolar bone of the mandibular second molars following molar protraction and investigate the factors associated with the alveolar bone changes. Materials and Methods Cone-beam computed tomography of 29 patients (mean age 22.0 ± 4.2 years) who had missing mandibular premolars or first molars and underwent molar protraction were reviewed. Alveolar bone level was measured as the distance from the cementoenamel junction at six points, buccal, lingual, mesiobuccal (MB), mesiolingual (ML), distobuccal (DB), and distolingual (DL), of the second molars at pretreatment (T0) and after molar protraction (T1). Factors associated with alveolar bone changes at the distal and mesial of the second molars were assessed. Results Mean alveolar bone changes ranged from −1.2 mm (bone apposition) to 0.8 mm (bone resorption). The presence of a third molar impaction at T0 (P < .001), third molar angulation at T0 (P < .001), and Nolla's stage of third molar at T0 (P = .005) were significantly associated with alveolar bone level changes distal to the second molars. Treatment duration (P = .028) was significantly associated with alveolar bone level changes mesial to the second molar. Conclusions Patients with impacted third molars, third molars at an earlier stage of development, and mesially angulated third molars at pretreatment may have less alveolar bone resorption distal to the second molars following protraction. Patients with increased treatment time may have reduced alveolar bone resorption mesial to the second molars.

Protraction of Mandibular Second Molar for Substitution of Adjacent Missing First Molar With a Mini-Implant-Anchored Albert Loop Appliance

“…molars at pretreatment may have less alveolar bone resorption distal to the second molars following protraction [20]. The patient, in this case, had a medium horizontal angle of the #48 initial state, a high Nolla stage, a young age, and the presence of large eruption dynamics, so it had more chances to erupt spontaneously and move mesially following the protraction of the second molars.…”

“…It has been proved that the younger the age, the larger the third molar Nolla stage, and the closer the mandibular third molar is to the occlusal plane, the more it tends to move proximally to the neighboring teeth [ 19 ]. Studies also indicated that patients with impacted and mesially angulated third molars at pretreatment may have less alveolar bone resorption distal to the second molars following protraction [ 20 ]. The patient, in this case, had a medium horizontal angle of the #48 initial state, a high Nolla stage, a young age, and the presence of large eruption dynamics, so it had more chances to erupt spontaneously and move mesially following the protraction of the second molars.…”

A patient with bimaxillary protrusion was treated by the extraction of four premolars and four compromised first molars: a case report

“…Therefore, compared with the anterior teeth, the posterior teeth are less susceptible to root resorption. 28 The treatment duration tends to be prolonged when molars are extracted, especially for individuals awaiting the eruption of the third molars. 22 This aspect is important and should be communicated to the patient at the start of treatment.…”

Application of surgical guide for pre-drilling for the successful placement of orthodontic mini-screws using CAD/CAM technology in two cases

“…This technique improves the quality of outcomes, makes the treatment of complex cases possible and is especially useful in less compliant or non-compliant patients (Jung, 2011; Lee et al, 2018). Using mini-screws as TAD, mandibular molar protraction was an alternative to conventional prosthetic treatment for missing second premolars or first molars (Baik et al, 2022). Distal movements of the mandibular molars were able to be accomplished by traction between lower dentition and mini-screws inserted in the mandibular buccal shelf (MBS) (Park et al, 2005) or in the retro-molar area (Poletti et al, 2013).…”