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Protraction of mandibular first and second molars in a patient congenitally missing a second premolar. (A) Before treatment. (B) Protraction using a temporary skeletal anchorage device. (C) After treatment.
Source publication
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...
Contexts in source publication
Context 1
... the mandibular first molar is an earlyerupting permanent tooth, it is easily exposed to dental caries or periodontitis, resulting in its being the most frequently missing tooth due to extraction. 1 In addition, the mandibular second premolar is one of the most frequently missing teeth congenitally. 2,3 Regardless of whether a tooth is missing due to extraction or agenesis, the excess space can be closed orthodontically by molar protraction (Figure 1). 4-8 Molar protraction can be challenging for clinicians, but with the aid of temporary anchorage devices (TADs), molars can be more easily protracted to close the space. ...
Context 2
... the mandibular first molar is an earlyerupting permanent tooth, it is easily exposed to dental caries or periodontitis, resulting in its being the most frequently missing tooth due to extraction. 1 In addition, the mandibular second premolar is one of the most frequently missing teeth congenitally. 2,3 Regardless of whether a tooth is missing due to extraction or agenesis, the excess space can be closed orthodontically by molar protraction (Figure 1). 4-8 Molar protraction can be challenging for clinicians, but with the aid of temporary anchorage devices (TADs), molars can be more easily protracted to close the space. ...
Citations
... The combination of the Albert protraction loop and mini-implant allows for more efficient protraction of the mandibular molars, avoiding mesial tipping and lingual rotation of the molars. 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. ...
Protraction of mandibular posterior teeth into edentulous regions is challenging in clinical practice. This case demonstrated a minor tooth movement of a mandibular second molar to substitute its adjacent missing first molar in a 15-year-old female. An efficient bodily movement of the mandibular second molar was achieved through a mini-implant-anchored protraction loop appliance. With this carefully designed biomechanical system, over 10-mm molar protraction was accomplished within 14 months without mesial or lingual tipping. The adjacent third molar erupted spontaneously during the protraction process and drafted mesially. Through brackets and segmented archwire after the protraction, the second and third molars were successfully protracted and good buccal interdigitation was achieved. The combination of the Albert protraction loop and mini-implant allows for more efficient protraction of the mandibular molars, avoiding mesial tipping and lingual rotation of the molars.
... 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. ...
The first molar has been reported to be the most caries prone tooth in the permanent dentition. Rarely is the extraction of the four first molars the ideal choice in orthodontic treatment, especially the extraction of four molars and four premolars. However, the extraction program presents a treatment alternative in selected cases. In the following case report, the orthodontic treatment is described a 15-year-old male patient who presented with a dentoskeletal bimaxillary protrusion, and a chief complaint of”crooked teeth”. Moreover, the patient had a skeletal Class I malocclusion with crowded dentitions, a hyperdivergent growth pattern, deviated midlines and an extremely deep Curve of Spee. A satisfactory treatment outcome was obtained by the extraction of four premolars and four compromised first molars. The mechanics involved alignment, levelling, detailing the occlusion using a straight arch wire technique followed by retention. The active treatment time was 48 months. The treatment successfully achieved a bilateral Class I relationship of the canines and the right molars, a mild Class III relationship of the left molars, a normal overjet and overbite, aligned dental midlines, optimal intercuspation and a harmonious facial profile. The occlusion remained stable during 5 years of review.
Introduction:
The alveolar bone loss (ABL) and external apical root resorption (EARR) depict the safety of mesialization of mandibular second molars into the extraction space of mandibular first molars. The aim of this study was to evaluate the ABL and EARR after closure of mandibular first molar extraction space by mesialization of second molar on extraction side (ES) as compared to the contralateral non-extraction side (NES).
Material and methods:
A retrospective cross-sectional study was carried out using the pre and posttreatment orthodontic records of young adults with complete set of permanent dentitions treated with extraction of unilateral mandibular first molar and non-extraction treatment on the contralateral side. All patients underwent mini-implant supported mesialization of second molar on ES. The ABL and EARR of second molar on ES and contralateral NES were measured on digital orthopantomograms. The ABL and EARR of second molars on ES and contralateral NES were compared using independent sample t-test.
Results:
A total of 36 subjects (14 males and 22 females) were included in the study. The mean treatment duration for molar mesialization was 28.75±8.05months. The mean crown and root movements of mandibular second molar on ES were 10.94±1.25mm and 9.04mm±1.14mm, as compared to 0.91±1.01mm and 0.77±0.83mm on contralateral NES, respectively. The mean ABL and EARR at mandibular second molar were found to be significantly greater on the ES than the contralateral NES (P<0.001 and<0.05, respectively). A total of seven patients (19.4%) experienced ABL≥1mm on ES as compared to none in the contralateral NES. EARR of>2mm of at least one root was found in seven patients (19.4%) in ES as compared to four (11%) in contralateral NES.
Conclusion:
There was small but statistically significant difference in the ABL and EARR of mesialized mandibular second molar at first molar ES as compared to the contralateral NES. For majority of patients this difference was small but few isolated cases experienced severe ABL and EARR.
Esta revisión de la literatura tuvo como objetivo mediante la recopilación de datos bibliográficos evaluar la reabsorción ósea en mesialización de molares anclado a miniimplantes con el uso de cadeneta elastómera y resorte cerrado, analizado mediante tecnología de la tomografía axial computarizada Cone Bean (CBCT) y radiografía panorámica, con la finalidad de dar a conocer al profesional ortodoncista una base bibliográfica acerca de este factor, se evaluaron variables como: la fuerza de tracción, la cantidad en milímetros de protracción y grado de reabsorción ósea, las bases de datos fue PubMed, Scopus, Chocrane, con descriptores verificados en DeCS y MeSH. Se concluye que la mesialización realizada con resorte cerrado presentó mayor grado de reabsorción ósea aunque la diferencia no fue clínicamente significativa comparada con cadeneta elastomérica, se necesita mayor evidencia clínica con el propósito de que ésta biomecánica permita suprimir en un futuro sobretratamientos protésicos y mejorar la longevidad ofreciendo un arquitectura armónica multidisciplinaria del sistema estomatognático
An increasing number of clinicians have been utilising orthodontic mini-screws as temporary anchorage devices (TAD) in their practices, but variable successful rates have been reported. Here, we introduce a practical approach to inserting mini-screws successfully. Using computer-aided design (CAD) and computer-aided manufacturing (CAM) technology, the surgical guide for pre-drilling was designed and fabricated and mini-screws were placed following pre-drilling holes in two cases. Two Ø2.0 × 10.0-mm mini-screws were inserted into the prepared holes in the mandibular buccal shelf (MBS) on both sides with a hand driver to distalise the lower molars for Class III correction. The treatment was done successfully, after 12 months of treatment in one case. Two Ø1.6 × 8.0-mm mini-screws were inserted into the prepared holes in the mandibular alveolar process in another case with congenital absence of lower right second premolar. One mini-screw was in the buccal alveolar process between the mandibular right canine and first premolar and the other in the lingual alveolar process between the mandibular right first premolar and second primary molar. The lower right molars would be protracted to close the space left after the extraction of the primary molar using the two mini-screws. The case was still in treatment.
