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Radiographic Evaluation of Predictors for Spontaneous Space Closure and Supereruption After the Loss of Permanent
Dane Lenaker1, Thorsten Grünheid2
1Southeast Alaska Regional Health Consortium, Juneau, Alaska, USA.
Purpose:
The purpose of this study was to evaluate pre-extraction variables associated with spontaneous space closure between the permanent second molar (PSM) and the second premolar following early extraction of the permanent first molar (PFM). Additionally, this study aimed to assess supereruption in compensated and uncompensated maxillary molars to determine if compensating extraction increases the odds of spontaneous space closure.
Methods:
A total of 134 patients aged six to 12 years with extracted PFM(s) were evaluated for spontaneous man- dibular space closure. Panoramic radiographs were reviewed to assess pre-extraction variables. Bitewing radiographs of 156 patients aged six to 13 years with previous PFM extractions were used to measure supereruption in compensated and uncompensated extractions. Both compensated and uncompensated extractions were evaluated for complete mandibular space closure.
Results:
Statistically significant predictors of space closure included extraction at age eight to 10 years (P=0.04; 95 percent confidence interval [95% CI] equals 0.08 to 0.91), permanent third molar presence (P=0.02; 95% CI equals 1.16 to 4.9), and follow-up time (P=0.001; 95% CI equals 1.16 to 1.69). The odds of uncompensated PFM super- eruption were greater than those of compensated PFM supereruption (P<0.001; 95% CI equals 1.86 to 6.92). Additional follow-up increased the odds of supereruption (P<0.001; 95% CI equals 1.08 to 1.30). Uncompensated extractions did not reduce the odds of spontaneous space closure (P=0.54; 95% CI equals 0.56 to 3.08).
Conclusions:
Permanent first molar extraction later than age 10 years is a negative predictor for spontaneous space closure, while permanent third molar presence is a positive predictor. Uncompensated maxillary PFMs do not inhibit spontaneous per- manent mandibular second molar space closure; however, uncompensated extractions are more likely to supererupt.
