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Spontaneous Space Closure in Patients Treated With the Early Extraction of the First Permanent Molar
abstract
This abstract is available on the publisher's site.
Access this abstract nowOBJECTIVES
To assess the success rate of spontaneous space closure after extraction of the first permanent molar (FPM) in the maxilla and the mandible, and to identify the factors that make spontaneous space closure most favorable in each.
MATERIALS AND METHODS
A retrospective records-based cohort study was conducted through a search of the database of the Public Dental Service, Stockholm County Council, Stockholm, for young adults born between 2000 and 2001, who underwent extraction of one or more FPM between 2006 and 2016. A total of 995 extracted teeth were identified, of which 203 teeth in 155 patients met the inclusion criteria.
RESULTS
Of the 203 extracted teeth, 166 (81.8%) did not receive any orthodontic treatment. The success rate for space closure in orthodontically treated patients was 91.9%. The success rate for spontaneous space closure was 84.3%. All unsuccessful spontaneous space closure in the maxilla occurred in patients older than 12 years. The dental developmental stage of the second permanent molar (SPM) had a statistically significant association with spontaneous space closure in the mandible (P < .001).
CONCLUSIONS
The success rate of spontaneous space closure was high (84.3%) and was higher in the maxilla (94.1%) than the mandible (74.1%). Age at time of extraction and dental developmental stage of the SPM were significant factors for successful spontaneous space closure in the maxilla and mandible, respectively.
Additional Info
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Spontaneous space closure in patients treated with early extraction of the first permanent molar: a retrospective cohort study using radiographs
Angle Orthod 2024 Mar 01;94(2)180-186, Y Aldahool, M Sonesson, L DimbergFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
This retrospective cohort study explored the success rate of spontaneous space closure following the extraction of the first permanent molar (FPM) in both the maxilla and mandible in patients aged between 6 and 15 years. The authors analyzed various factors associated with this success, such as the engagement of the second premolar under the roots of the primary second molar, mesial angulation of the second permanent molar (SPM), the presence of a third molar, and other secondary outcomes. The success of space closure was assessed radiographically when patients were 19 to 20 years old.
The results showed that, among patients who did not undergo orthodontic treatment, the rate of spontaneous space closure was notably high, reaching 84.3%, despite the high average age at the time of extraction (11.4 years). Closure rates were higher in the maxilla (94.1%) than in the mandible (74.1%), as previously reported in other studies.1,2 The study highlights age at the time of extraction (with a cutoff at 12 years) and the dental developmental stage of the SPM (the most favorable being Demirjian’s stages E and F) as significant factors influencing the rate of spontaneous space closure in the maxilla and mandible, respectively.
There is a lack of consensus regarding the primary factors contributing to spontaneous space closure following the early extraction of the FPM, and these factors are different for the maxilla and mandible. Some studies suggest that the optimal timing for extracting the FPM in the maxilla is before the SPM erupts and before the crown of the SPM surpasses the cementoenamel junction of the FPM.3–5 As for the mandible, it is recommended to extract the FPM when the crown of the SPM is fully formed and the furcation is visible on radiographs, typically between 8 and 10 years of age.3,4,6,7 Additionally, a mesial angulation of the SPM and the engagement of the second premolar under the roots of the primary second molar in the mandible are also considered beneficial factors.3,7,8 The presence of a third molar is considered advantageous too, particularly in the mandible.3,6,7
However, this study did not find evidence to support the idea that the engagement of the second premolar under the roots of the primary second molar, mesial angulation of the SPM, or the presence of the third molar significantly contributes to successful spontaneous space closure.
It is important to note the large sample size and the use of multilevel statistical techniques in this study. However, the inclusion of various types of radiographs, such as panoramic and intraoral periapical radiographs, taken within a maximum of 6 months before the extraction may have introduced potential confounding factors. Additionally, the lower number of failures in the maxilla precluded the application of multivariate techniques, and only bivariate analyses could be conducted. Chronological age may not be a reliable predictor owing to its poor correlation with dental age.
References