Lower third molar development subsequent to second molar extraction

doi:10.1016/S0889-5406(05)80440-8

American Journal of Orthodontics and Dentofacial Orthopedics

Volume 104, Issue 6, December 1993, Pages 566-574

https://doi.org/10.1016/S0889-5406(05)80440-8 Get rights and content

Development and eruption of lower third molars was examined in 63 subjects who were treated by extraction of second molars. Changes in mesiodistal and buccolingual lower third molar angulation were measured on 60° cephalograms taken before extraction and 3 or more years later. The final position of lower third molars was assessed on models at the end of the observation period by using a scoring system. All lower third molars erupted in periods ranging from 3 to 10 years after extraction. Ninety-nine percent of the third molars uprighted mesiodistally, but few became as upright as the second molars they replaced. Model analysis showed that 96% of the lower third molars erupted in good or acceptable positions.

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Cited by (44)

Surgical uprighting of mandibular second molars: A single-group retrospective cohort study
2020, American Journal of Orthodontics and Dentofacial Orthopedics
The management of impacted, unerupted, or malpositioned mandibular second molars with orthodontic therapy requires special attention in order to achieve normal anatomic positioning within the dental arch. We present a surgical approach to managing these teeth combining exposure and surgically-assisted forced eruption.
This retrospective single-group cohort study followed 260 impacted mandibular second molars. The molars were exposed and surgically uprighted. An orthodontic bracket was bonded to aid in orthodontic traction, and the wound was packed to prevent soft tissue growth over the crown of the exposed molar. Patients were followed for a minimum of 6 months after uprighting, during which the following outcomes were measured: the degree of success of the eruption one the basis of the clinical occlusal relationship to the opposing dentition, radiographic evidence of bone fill, the periodontal status of the teeth involved, and tooth vitality.
A total of 260 mandibular second molars were uprighted in 177 patients (83 female, 94 male) with an average age of 14.8 years. Outcomes showed that 255 molars (98.1%; 95% confidence interval, 96.3-99.8) were successfully uprighted. Complications included infection/abscess in 3 molars and fractured root requiring extraction in 2 molars. All remaining 255 teeth tested vital, 17 teeth had periodontal pocketing of more than 5 mm, and 235 of the teeth had occlusal contact after healing.
Surgically-assisted forced eruption with or without orthodontic forced eruption is a safe, successful, and viable approach to managing unerupted or malpositioned mandibular second molars in the adolescent population.
The management of mesially inclined/impacted mandibular permanent second molars
2020, Journal of the World Federation of Orthodontists
Mesially impacted mandibular second molars are a common occurrence in orthodontic practices, especially those using the lingual arch or lip bumper for alleviating anterior crowding. Horizontally impacted second molars, on the other hand, occur so infrequently that most practitioners have limited experience in treating such a patient. Because of this there is little consensus on the management of these cases. As opposed to vertically impacted molars that may be associated with ankylosis or other factors preventing eruption, the mesially angulated, horizontally impacted mandibular second molar usually has eruption potential, because its impaction is more commonly due to lack of space and/or abnormal eruption path. Hence, orthodontic uprighting shows the most promise and can commonly be done without extracting the third molar or surgically exposing the impacted second molar. Modern clinicians have at their disposal a myriad of biomechanical choices that can be used to successfully reposition these teeth and enable finishing with an optimal occlusion.
Second Molar Protraction and Third Molar Uprighting
2020, Temporary Anchorage Devices in Orthodontics
Recently, with the help of temporary anchorage devices, substantial mandibular second molar protraction into the missing mandibular first molar (L-6) space or retained deciduous mandibular second molars, with missing succedaneous premolar (L-E) space, has become possible. After second molar protraction, even a horizontally impacted third molar can be uprighted and used. This chapter discusses the movement of 107 impacted mandibular third molars after second molar protraction. The impacted third molar moved spontaneously, without any appliances, during second molar protraction, in multidimensional direction. Vertically, it erupted spontaneously, without using any appliances. Horizontally, it followed the second molar, in general; however, in some cases, it did not. The angular changes are various. In some cases, the angle did not change; in some cases, it was uprighted; while, in some cases, it tilted more. Alveolar bone changes of the second and third molar are variable. Second molar protraction into the space created because of missing posterior teeth will become good treatment modality, replacing implants and bridges.
Factors associated with spontaneous angular changes of impacted mandibular third molars as a result of second molar protraction
2019, American Journal of Orthodontics and Dentofacial Orthopedics
This study aimed to identify significant factors affecting the spontaneous angular changes of impacted mandibular third molars as a result of second molar protraction. Temporary skeletal anchorage devices in the missing mandibular first molar (ML-6) or missing deciduous mandibular second molar (ML-E) with missing succedaneous premolar spaces provided traction.
Forty-one mandibular third molars of 34 patients (10 male and 24 female; mean age 18.3 ± 3.7 years) that erupted after second molar protraction were included in this study. They were classified into upright (U) and tilted (T) groups. Linear and angular measurements were performed at the time of treatment initiation (T1) and of ML-6 or ML-E space closure (T2). Regression analyses were used to identify significant factors related to third molar uprighting.
Nolla stage (odds ratio [OR] 4.1), sex (OR 0.003 for male), third molar angulation at T1 (OR 1.1), missing tooth space (OR 0.006), rate of third molar eruption (OR 23.3), and rate of second molar protraction (OR 0.2) significantly affected third molar uprighting. Age, third molar angulation at T1, rate of third molar eruption, and rate of second molar protraction were significant factors for predicting third molar angulation at T2.
Available space for third molar eruption before and after second molar protraction is not associated with uprighting of erupting third molars. Older patients whose third molars are in greater Nolla stage, are in a more upright position at T1, and have a greater eruption rate have a greater chance for third molar uprighting. Alternatively, an increase in second molar protraction rate results in mesial tipping of the third molars.
In Reply
2017, Journal of Oral and Maxillofacial Surgery
The effect of first and second premolar extractions on third molars: A retrospective longitudinal study
2017, Journal of Dentistry
Citation Excerpt :
Several authors reported that most lower and upper third molars erupted successfully after the extraction of second molars [16–19]. Richardson and Richardson as well as De-la Rosa-Gay et al. also found that the less developed the third molar is at the time of second molar extraction, the higher the chances are for its eruption [17,18]. Bayram et al., Livas et al. and Halicioglu et al. investigated the effect of first molar extractions on third molar eruption [20–22].
To analyse the effect of first and second premolar extractions on eruption space for upper and lower third molars and on third molar position and angulation during orthodontic treatment.
The sample consisted of 296 patients of which 218 patients were orthodontically treated without extraction and 78 patients with extraction of first or second premolars. The eruption space for third molars was measured on pre– and posttreatment lateral cephalograms, whereas the angulation, vertical position, the relation with the mandibular canal and the mineralization status of third molars were evaluated using pre– and posttreatment panoramic radiographs. All data were statistically analyzed.
The increase in eruption space and the change in vertical position of upper and lower third molars significantly differed between patients treated with and without premolar extractions, whereas the change in angulation, relationship with the mandibular canal and mineralization status of the third molars did not significantly differ between patients treated with and without premolar extractions.
The retromolar space and the position of third molars significantly change during orthodontic treatment in growing patients. Premolar extractions have a positive influence on the eruption space and vertical position of third molars, whereas they do not influence the angular changes of third molars. Due to the retrospective character of the study, these conclusions should be carefully considered. Further prospective research is necessary for better insights into this complex topic.
This study stresses the importance of considering the possible effects of orthodontic treatment on third molars during treatment planning.

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^a: Associate Specialist Orthodontist, Orthodontic Division, School of Clinical Dentistry, Royal Victoria Hospital.

^b: Professor of Orthodontics, The Queen's University of Belfast, Orthodontic Division, School of Clinical Dentistry.

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Lower third molar development subsequent to second molar extraction

Am J Orthod Dentofac Orthop

Am J Orthod

Am J Orthod Dentofac Orthop

Am J Orthod Dentofac Orthop

Am J Orthod Dentofac Orthop

Am J Orthod Dentofac Orthop

Am J Orthod Dentofac Orthop

The eruption of lower third molars following the loss of lower second molars: a longitudinal cephalometric study

Br J Orthod

Early second permanent molar extractions in orthodontics

J Can Dent Assoc

Indications for extraction of the lower second permanent molar

Br Soc Study Orthod Trans

A consideration of the advantages of second molar extraction in orthodontics

Eur J Orthod

Third molar development following second molar extractions

J Pedod

Extraction of four second molars

Angle Orthod

Second molar removal, third molar replacement

Funct Orthod